Mold apparatus for sandwich molded body and method for manufacturing sandwich molded body

Abstract

To provide a mold assembly for a sandwich molded article, that molds an accurately molded sandwich molded article in which heat resistance is ensured, and a method for molding the sandwich molded article using the mold assembly for a sandwich molded article.SOLUTION: A mold assembly for a sandwich molded article comprises: a cavity portion in which the sandwich molded article is formed; a primary gate for supplying a skin material that constitutes a skin layer to the cavity portion; a secondary gate for supplying a core material that constitutes a core layer to the cavity portion; and an overflow portion from which the surplus skin material and the core material are discharged during injection molding. The overflow portion is a space formed along an edge portion of the cavity portion.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to, for example, a mold device for a sandwich molded body used to mold a sandwich molded body forming an automotive outer panel or the like, and a sandwich molded body using the mold device for the sandwich molded body. Manufacture of It relates to a method.

Background Art

[0002] In recent years, from the viewpoint of weight reduction, resin outer panels have been used as automotive outer panels such as bumpers and fenders instead of conventional metal outer panels. As a member for forming such a resin outer panel, a sandwich molded body made of different materials for an intermediate core layer and skin layers sandwiching the core layer from the front and back is known (for example, see Patent Document 1). In the above-mentioned sandwich molded body, an example is known in which a polypropylene resin excellent in appearance is used for the skin layer, and a composite material of polypropylene excellent in mechanical properties and glass fiber or carbon fiber is used for the core layer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when sandwich molding a complicated shape such as a sliding door, various problems occur. For example, when the above-mentioned sandwich molded body is injection molded, as shown in FIG. 10, a skin material for forming a skin layer may accumulate at the four corner portions and the central portion of the sliding door, forming a skin material accumulation 104. In this case, warpage occurs in the panel constituting the sliding door, deteriorating the molding dimensional accuracy, or problems such as deformation of the panel during in-line painting occur because heat resistance cannot be ensured due to insufficient filling of the core material.

[0005] In addition, a core material overflow 106 that forms a core material may occur in the welded portion. In this case, problems such as the fibers protruding from the outer plate, resulting in a rough surface roughness and deterioration of the outer plate quality, may occur.

[0006] An object of the present invention is to provide a sandwich molding die device for molding a sandwich molded body that is accurately molded and has heat resistance ensured, and a sandwich molded body using the sandwich molding die device. Manufacture of The method is to provide.

Means for Solving the Problems

[0007] The sandwich molding die device of the present invention is A sandwich molding die device having a die for injection molding a sandwich molded body formed of different resin materials for a core layer located in the middle and skin layers sandwiching the core layer from the front and back, The die is A cavity portion where the sandwich molded body is formed, A primary gate for supplying a skin material constituting the skin layer to the cavity portion, A secondary gate for supplying a core material constituting the core layer to the cavity portion, An overflow portion where the excess skin material and the core material are discharged during injection molding And The overflow portion is a space formed along the edge of the cavity portion.

[0008] In this way, by forming an overflow portion along the edge of the cavity portion, the die is opened at a specific timing, the resin material is discharged to the overflow portion, and the core material is spread to the end of the cavity portion, so that the filling rate of the core material can be increased. For this reason, it is possible to prevent a situation where the panel warps and the molding dimensional accuracy deteriorates, or the panel deforms because heat resistance cannot be ensured due to insufficient filling of the core material. Therefore, a sandwich molded body that is accurately molded and has heat resistance ensured can be molded.

[0009] In addition, the mold device for a sandwich molded body of the present invention is characterized in that a blocking portion for blocking the cavity portion and the overflow portion is formed between the cavity portion and the overflow portion in a state where the mold is closed. Thus, by providing the blocking portion, it is possible to clearly distinguish the main body and the surplus portion for the sandwich molded body after the completion of the sandwich molded body.

[0010] In addition, the mold device for a sandwich molded body of the present invention is characterized in that the overflow portion includes an outer overflow portion that surrounds most of the outer periphery of the cavity portion and an inner overflow portion that is surrounded by the inner periphery of the cavity portion.

[0011] Thus, by surrounding most of the outer periphery of the cavity portion with the outer overflow portion, the core material can be spread over the entire periphery of the cavity portion. Further, by forming the inner overflow portion on the inner periphery of the cavity portion, even when there is an opening such as a window portion in the panel, it can be molded with high precision.

[0012] In addition, the mold device for a sandwich molded body of the present invention includes an opening / closing control portion for opening and closing the mold, and the opening / closing control portion is any one of a hydraulic cylinder, an air cylinder, and an electric control portion. Thus, it is possible to apply a plurality of types of devices to the opening / closing control portion.

[0013] In addition, the mold device for a sandwich molded body of the present invention is characterized in that the sandwich molded body after mold release is a panel used for an automobile outer panel. That is, the mold device for a sandwich molded body of the present invention is suitably used for molding an automobile outer panel.

[0014] In addition, the method for molding a sandwich molded body of the present invention A method for forming a sandwich molded body using the above-described mold apparatus for a sandwich molded body, a first opening step of opening the mold, a closing step of closing the mold after the first opening step, a second opening step of opening the mold again after the closing step, a cooling step of cooling the mold after the second opening step comprising: wherein the first opening step, the closing step, and the second opening step are performed during injection of the resin material, and the cooling step is performed after injection of the resin material. Thus, by repeating the opening and closing of the mold during injection of the resin material, the resin material can be accurately discharged to the overflow portion, and the core material can be surely spread to the end of the cavity portion.

[0015] Further, the method for forming a sandwich molded body of the present invention is characterized in that both the first opening step and the second opening step are performed while the core material is being injected into the cavity portion. Thus, by opening the mold when the core material is being injected, the core material can be more surely spread to the end of the cavity portion.

[0016] Further, the method for forming a sandwich molded body of the present invention is characterized in that the core material injected during a period overlapping with the first opening step is injected from the first secondary gate, and the core material injected during a period overlapping with the second opening step is injected from the second secondary gate. Thus, by opening the mold each time the core material is injected from each secondary gate, the core material can be more surely spread to the end of the cavity portion.

[0017] Further, the method for forming a sandwich molded body of the present invention is characterized in that the first opening step is performed in overlapping with a pressurizing step of applying a holding pressure to the mold. As a result, the fibers contained in the core material are more uniformly dispersed, and deformation of the obtained sandwich molded body can be suppressed.

Advantages of the Invention

[0018] According to the present invention, there are provided a mold device for a sandwich molded body that molds a sandwich molded body that is accurately molded and has heat resistance ensured, and a sandwich molded body using the mold device for a sandwich molded body. Manufacture of A method can be provided.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1(a) is a schematic view of the cavity 20 of a mold apparatus for a sandwich molded body (hereinafter abbreviated as a mold apparatus) according to an embodiment, viewed from the front, and FIG. 1(b) is a mold 4 portion of the A-A cross section shown in FIG. 1(a). Further, FIG. 2 is a schematic view of the mold apparatus 2 shown in FIG. 1(a) viewed from the side.

[0021] The mold apparatus 2 is an apparatus used for molding a sandwich molded body 30 (see FIG. 9) made of different resin materials for a core layer located in the middle and skin layers sandwiching the core layer from the front and back. As shown in FIGS. 1 and 2, a mold 4 having a rectangular planar shape, a first resin unit (not shown) for supplying a skin material 32 (see FIG. 4), which is a first resin material constituting the skin layer, to the mold 4, a second resin unit (not shown) for supplying a core material 34 (see FIG. 4), which is a second resin material constituting the core layer, to the mold 4, a first nozzle 8 that is a flow path for the skin material 32, a second nozzle 10 that is a flow path for the core material 34, a hydraulic cylinder (not shown) that is an opening / closing control unit for opening and closing the mold 4, and a control sensor 12 (see FIG. 5) for controlling the opening degree of the mold 4.

[0022] Note that primary gates 8a and 8b, which are supply ports for the skin material 32, are respectively provided at the tips of the first nozzle 8, and secondary gates 10a and 10b, which are supply ports for the core material 34, are respectively provided at the tips of the second nozzle 10.

[0023] And, as shown in FIG. 1(b), the mold 4 includes a fixed mold 4a and a movable mold 4b. Further, in the mold 4, a cavity 20 in which the sandwich molded body 30 is formed, a film gate 22 that is an inlet for the resin material into the cavity 20, and an overflow portion 24 for discharging excess resin materials (skin material 32, core material 34) from the cavity 20 during injection molding are formed.

[0024] Here, the cavity 20 is supplied with the skin material 32 by the primary gates 8a and 8b from both ends thereof, and is supplied with the core material 34 by the secondary gates 10a and 10b. Further, the overflow portion 24 is formed along the edge of the cavity portion 20. The overflow portion 24 includes an outer overflow portion 24a that surrounds most of the outer periphery of the cavity portion 20 (the portion other than the film gate 22), and an inner overflow portion 24b that surrounds the outer periphery of the window portion 23 formed in the cavity portion 20 (surrounded by the inner periphery of the cavity portion 20 in the window portion 23).

[0025] Also, between the overflow portion 24 and the cavity portion 20, a blocking portion 18 that blocks the overflow portion 24 and the cavity portion 20 when the mold 4 is closed is formed. Specifically, between the outer overflow portion 24a and the cavity portion 20, a first blocking portion 18a protruding from the fixed mold 4a is formed on the outer overflow portion 24a side, and a second blocking portion 18b protruding from the movable mold 4b is formed on the cavity portion 20 side. Similarly, between the inner overflow portion 24b and the cavity portion 20, a first blocking portion 18a protruding from the fixed mold 4a is formed on the inner overflow portion 24b side, and a second blocking portion 18b protruding from the movable mold 4b is formed on the cavity portion 20 side.

[0026] Next, a method of molding a sandwich molded body 30 (see FIG. 9) using the mold apparatus 2 will be described with reference to the table shown in FIG. 3 by taking as an example the case of manufacturing a panel constituting a sliding door among automotive outer panels. First, as shown in FIG. 1(b), the movable mold 4b, which is movable, is moved in the direction of the fixed mold 4a to close the mold 4. Next, the primary gate 8a of the mold 4 is opened by a gate opening / closing portion (not shown), and when the skin material 32 that becomes the surface layer of the sandwich molded body 30 is injected into the first nozzle 8 by the first resin unit, the skin material 32 is supplied from the primary gate 8a to the cavity portion 20 as shown in FIG. 4(a). Here, as shown in FIG. 3, with the start of molding when the skin material 32 is first injected as the reference time, the skin material 32 continues to be injected from the primary gate 8a for 3 seconds from the reference time.

[0027] Next, two seconds after the reference time, the secondary gate 10a of the mold 4 is opened by the gate opening / closing unit, and when the core material 34 that becomes the intermediate layer of the sandwich molded body 30 is injected into the second nozzle 10 by the second resin unit, the core material 34 is supplied from the secondary gate 10a to the cavity 20. The core material 34 also continues to be injected from the secondary gate 10a for three seconds from the reference time.

[0028] Here, the supply of the core material 34 from the secondary gate 10a is performed in a state where a holding pressure is applied to the mold 4 by an injection cylinder (not shown). That is, the application of the holding pressure starts two seconds after the reference time and continues for three seconds. By such pressurization, the uniformity of the distribution of the fibers contained in the core material 34 is enhanced.

[0029] As a result, as shown in FIG. 4(a), the skin material 32 and the core material 34 are filled in the portion constituting the upper part of the slide door (the side where the window portion 23 is located). Three seconds after the reference time, the injection of the skin material 32 by the first resin unit is stopped, and the primary gate 8a is closed by the gate opening / closing unit. Also, as shown in FIG. 4(b), the movable mold 4b is moved by a hydraulic cylinder (not shown) to open the mold 4 (first opening step). As a result, the cavity 20 is expanded, and the surplus skin material 32 and core material 34 are discharged to the overflow portion 24.

[0030] In addition, when the mold 4 is in the open state, the distance T between the fixed mold 4a and the movable mold 4b is preferably 0.3 mm or more and 1.0 mm or less, and more preferably 0.4 or more and 0.7 mm or less.

[0031] The state where the mold 4 is open is held for 2.5 seconds, and 4.5 seconds after the reference time, as shown in FIG. 3(c), the movable mold 4b is moved toward the fixed mold 4a side by a hydraulic cylinder to close the mold 4 (closing step).

[0032] Five seconds after the reference time, the pressurization of the holding pressure is stopped, and the injection of the core material 34 by the second resin unit is stopped. The secondary gate 10a is closed by the gate opening / closing unit. At the same time, the primary gate 8b is opened, and the skin material 32 is supplied to the cavity 20, and the skin material 32 continues to be injected for 3 seconds. Eight seconds after the reference time, the injection of the skin material 32 by the first resin unit is stopped, and the primary gate 8b is closed by the gate opening / closing unit.

[0033] At the same time, the secondary gate 10b is opened, and the core material 34 is supplied to the cavity 20 and continues to be injected for 3 seconds. During this time, nine seconds after the reference time, as shown in FIG. 3(b), the mold 4 is opened again (second opening step), and the surplus skin material 32 and core material 34 are discharged to the overflow portion 24. The state in which the mold 4 is opened is held for 2.5 seconds, and 10.5 seconds after the reference time, the mold 4 is closed again as shown in FIG. 3(c).

[0034] Here, FIG. 5 is a cross-sectional view of the mold apparatus 2 viewed from above during the supply of the core material 34, and FIG. 6 is an enlarged view of the portion within the circle shown in FIG. 5 after the supply of the core material 34 is completed. As described above, by opening the mold 4 during the injection molding of the core material 34 to temporarily expand the space of the cavity 20, as shown in FIGS. 5 and 6, the core material 34 can be spread to the end of the cavity 20, and the filling rate of the core material 34 can be increased.

[0035] Note that FIG. 7 is a cross-sectional view of the mold apparatus 2 viewed from above when the resin material is supplied to the cavity 20 without opening the mold 4 as in the conventional case, and FIG. 8 is an enlarged view of the portion within the circle shown in FIG. 7. In this case, as shown in FIGS. 7 and 8, the core material 34 cannot be spread to the end of the cavity 20.

[0036] Eleven seconds after the reference time, the injection of the core material 34 by the second resin unit is stopped, and the secondary gate 10b is closed by the gate opening / closing unit. At the same time, a cooling device (not shown) operates to cool the mold 4 for 20 seconds (cooling step). Note that the cooling time is preferably 10 seconds or more and 30 seconds or less.

[0037] When the skin material 32 and the core material 34 in the cavity 20 are cured by cooling, a sandwich molded body 30 in which both are integrated is formed. Further, when the movable mold 4b is moved and the mold 4 is opened, the sandwich molded body 30 is released as a panel.

[0038] According to the invention according to this embodiment, an overflow portion 24 is formed along the edge of the cavity 20, and by opening the mold 4 at a specific timing, the resin material is discharged to the overflow portion 24 to spread the core material 34 to the end of the cavity 20, and the filling rate of the core material 34 can be increased. For this reason, it is possible to prevent a situation in which the panel is warped and the molding dimensional accuracy deteriorates, or the panel is deformed because heat resistance cannot be ensured due to insufficient filling of the core material 34. In addition, since it is difficult for the core material 34 to overflow at the weld portion (see FIG. 10), it is possible to prevent deterioration of the quality of the panel, such as fibers protruding on the panel and the surface roughness becoming rough. Therefore, it is possible to mold the sandwich molded body 30 that is accurately molded and has heat resistance ensured.

[0039] Further, by surrounding most of the outer periphery of the cavity 20 with the outer overflow portion 24a, the core material 34 can be spread over the entire periphery of the cavity 20. Further, by forming the inner overflow portion 24b on the inner periphery of the cavity 20, even when there is an opening such as a window portion 23 in the panel, it can be accurately molded.

[0040] Further, by repeating the opening and closing of the mold 4 during the injection molding of the resin material, the resin material can be accurately discharged to the overflow portion 24, and the core material 34 can be surely spread to the end of the cavity 20.

[0041] Further, by opening the mold 4 when the core material 34 is being injected, the core material 34 can be more surely spread to the end of the cavity 20. Further, by opening the mold 4 each time the core material 34 is injected from each of the secondary gates 10a and 10b, the core material 34 can be more surely spread to the end of the cavity 20.

[0042] Also, by executing the first opening process in overlap with the pressurization process, the fibers contained in the core material 34 can be more uniformly dispersed, and deformation of the obtained sandwich molded body 30 can be suppressed.

[0043] In addition, in the above-described embodiment, the case where the opening / closing control unit is a hydraulic cylinder is exemplified. However, instead of the hydraulic cylinder, an air cylinder or an electric control unit may be used as the opening / closing control unit.

[0044] Also, in the above-described embodiment, the table shown in FIG. 3 is an example, and the injection time of the resin material and the opening time of the overflow portion 24 do not necessarily have to be exactly these times, and various changes can be made without departing from the object of the present invention.

[0045] Also, in the sandwich molded body 30 in the above-described embodiment, an automotive outer panel having the window portion 23 is exemplified. However, of course, the present invention is also applicable when manufacturing the sandwich molded body 30 that does not have the window portion 23.

[0046] Also, in the above-described embodiment, the skin material 32 contains a propylene-based resin. Examples of the propylene-based resin include a propylene homopolymer, and a copolymer of propylene and at least one selected from ethylene and an α-olefin having 4 or more carbon atoms. The copolymer may be a propylene-based random copolymer or a propylene-based block copolymer.

[0047] Examples of α-olefins having 4 or more carbon atoms include α-olefins having 4 to 20 carbon atoms such as 1-butene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 2-ethyl-1-butene, 2,3-dimethyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3,3-dimethyl-1-butene, 1-heptene, methyl-1-hexene, dimethyl-1-pentene, ethyl-1-pentene, trimethyl-1-butene, methylethyl-1-butene, 1-octene, methyl-1-pentene, ethyl-1-hexene, dimethyl-1-hexene, propyl-1-heptene, methylethyl-1-heptene, trimethyl-1-pentene, propyl-1-pentene, diethyl-1-butene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, etc. Among these, 1-butene, 1-pentene, 1-hexene, and 1-octene are preferred.

[0048] As the propylene-based resin, a propylene homopolymer and a propylene-based block copolymer are preferred. The propylene-based block copolymer is also called impact polypropylene and is usually a mixture of a polypropylene homopolymer and a propylene-ethylene copolymer.

[0049] The propylene-based resin may contain a propylene-based resin modified with an unsaturated carboxylic acid such as maleic anhydride, fumaric acid, (meth)acrylic acid or a derivative thereof. In such a modified propylene-based resin, the content ratio of the unsaturated carboxylic acid or its derivative is preferably 0.01 to 10% by mass.

[0050] The core material 34 contains a fiber-reinforced propylene-based resin. The fiber-reinforced propylene-based resin imparts excellent heat resistance and mechanical strength to the molded body of the present embodiment. Examples of the propylene-based resin in the fiber-reinforced propylene-based resin include the propylene-based resins described in the explanation of the skin material 32. However, the propylene-based resin contained in the fiber-reinforced propylene-based resin and the propylene-based resin contained in the skin material 32 may be the same resin or different resins. Also, part or all of the propylene-based resin may be a recycled material.

[0051] Examples of the fiber in the fiber-reinforced propylene-based resin include glass fiber; carbon fiber; metal fibers such as aluminum fiber, aluminum alloy fiber, copper fiber, brass fiber, steel fiber, stainless steel fiber, and titanium fiber; natural fibers such as cotton fiber, silk fiber, wood fiber, and cellulose fiber; ceramic fibers such as silicon carbide fiber, silicon nitride fiber, alumina fiber, and zirconia fiber; and synthetic fibers made of synthetic resins such as wholly aromatic polyamide (aramid), wholly aromatic polyester, wholly aromatic polyester amide, wholly aromatic polyether, wholly aromatic polycarbonate, wholly aromatic polyazomethine, polyphenylene sulfide, poly(paraphenylene benzobisoxazole), poly(paraphenylene benzobisthiazole), polybenzimidazole, polyether ether ketone, polyamide imide, polyimide, polytetrafluoroethylene, polyvinyl alcohol, polyolefin, polyarylate, and fluoropolymer. Examples of the glass fiber include filamentous fibers obtained by melt spinning glass such as E glass, C glass, S glass, and alkali-resistant glass. Among the fibers, glass fiber and carbon fiber are preferred from the viewpoints of rigidity and heat resistance.

[0052] The fiber may be subjected to surface treatment such as coupling agent treatment, surfactant treatment, ultraviolet irradiation treatment, electron beam irradiation treatment, and plasma irradiation treatment, if necessary. Examples of the coupling agent include amino group-containing alkoxysilanes such as γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane, and their hydrolyzates.

[0053] The fiber may be a short fiber or a long fiber, but long fibers are preferred because of the excellent physical properties of the resulting molded body, and short fibers are preferred from the viewpoint of fluidity during molding. Further, a mixed fiber of short fibers and long fibers can also be used. The short fiber may be a chopped fiber (cut fiber)-like short fiber or a pulp-like short fiber having fibrils.

Explanation of symbols

[0054] 2 Mold device 4 Mold 4a Fixed mold 4b Movable mold 8 Nozzle 8a, 8b Primary gate 10 Nozzle 10a, 10b Secondary gate 12 Control sensor 18 Shut-off part 18a First shut-off part 18b Second shut-off part 20 Cavity part 22 Film gate 23 Window part 24 Overflow part 24a Outer overflow part 24b Inner overflow part 30 Sandwich molded body 32 Skin material 34 Core material 104 Skin material reservoir 106 Core material overflow

Claims

1. A mold for injection molding a sandwich molded body made of different resin materials for a core layer located in the middle and skin layers sandwiching the core layer from the front and back, and an opening / closing control unit for controlling the opening and closing operation of the mold. The mold for a sandwich molded body has: The mold has: A cavity where the sandwich molded body is formed, A primary gate for supplying a skin material that constitutes the skin layer to the cavity, A secondary gate for supplying a core material that constitutes the core layer to the cavity, An overflow portion that is a space formed along the edge of the cavity and where excess skin material and core material are discharged during injection molding, and is provided with: The opening / closing control unit, while the core material is being injected into the cavity, opens the mold to shift from a closed state where the overflow portion and the cavity are blocked to an open state where the overflow portion and the cavity communicate, a first opening operation, after the first opening operation, closes the mold to shift from the open state to the closed state, a closing operation, and controls the opening and closing operation of the mold so as to perform the above operations. A mold device for a sandwich molded body is characterized by this.

2. The mold device for a sandwich molded body according to claim 1, further comprising a cooling unit for cooling the mold, wherein the cooling unit cools the mold after the closing operation is completed and the core material is injected into the cavity.

3. The mold device for a sandwich molded body according to claim 1 or 2, characterized in that a blocking portion for blocking the cavity and the overflow portion is formed between the cavity and the overflow portion in a state where the mold is closed.

4. The mold device for a sandwich molded body according to any one of claims 1 to 3, characterized in that the overflow portion includes an outer overflow portion surrounding most of the outer periphery of the cavity and an inner overflow portion surrounded by the inner periphery of the cavity.

5. The mold device for a sandwich molded body according to any one of claims 1 to 4, characterized in that the opening / closing control unit is any one of a hydraulic cylinder, an air cylinder, and an electric control unit.

6. The sandwich molded body after demolding is a panel used for an automobile outer panel. The mold device for a sandwich molded body according to any one of claims 1 to 5 is characterized by this. A method for manufacturing a sandwich molded body using a mold apparatus for a sandwich molded body having a mold for injection molding a sandwich molded body made of different resin materials for a core layer located in the middle and skin layers sandwiching the core layer from the front and back, wherein the mold has a cavity portion in which the sandwich molded body is formed, a primary gate for supplying a skin material constituting the skin layer to the cavity portion, a secondary gate for supplying a core material constituting the core layer to the cavity portion, an overflow portion which is a space formed along the edge of the cavity portion and from which excess of the skin material and the core material are discharged during injection molding and is provided with a first opening step of opening the mold during injection of the core material into the cavity portion to shift from a closed state in which the overflow portion and the cavity portion are blocked to an open state in which the overflow portion and the cavity portion communicate with each other, a closing step of closing the mold to shift from the open state to the closed state during injection of the core material into the cavity portion after the first opening step characterized by including A method for manufacturing a sandwich molded body according to claim 7, further comprising a cooling step of cooling the mold after the closing step is completed and the core material is injected into the cavity portion.

9. The method for manufacturing a sandwich molded body according to claim 7 or 8, wherein the first opening step is executed in overlapping with a pressurizing step of applying a holding pressure to the mold.

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