JP7257605B2 - Foam core material, resin sandwich panel, and method for manufacturing resin sandwich panel - Google Patents

Description

TECHNICAL FIELD The present invention relates to a foam core material, a resin sandwich panel, and a method for manufacturing a resin sandwich panel.

2. Description of the Related Art Conventionally, there has been provided a resin sandwich panel formed by sandwiching a substantially flat foamed core material between two molten resin sheets. Patent Literature 1 discloses a resin sandwich panel in which an outer peripheral space is formed on the outer periphery of a foam core material. Grid-like grooves are formed on the surface of the foamed core material to reduce air pockets when the foamed core material is sandwiched between two molten resin sheets (during mold clamping). In this way, the foam core may have a space formed on its outer periphery, and the foam core is inserted into the molten resin sheet formed in the mold cavity, so that the mold cavity formed smaller than

JP 2015-104887 A

The foam core material is supported by a robot hand or the like and inserted into the mold cavity. When the foam core is inserted into the mold cavity and pressed against the molten resin sheet, the surface of the foam core pressed against the molten resin sheet is melted and welded. Thereafter, the foam core material is removed from the support of the robot hand or the like, and clamped together with the two molten resin sheets. In this manner, the surface of the foamed core material is welded to the molten resin sheet and held in the cavity from the time the support by the robot hand or the like is released until the mold is clamped. Depending on the size, the weight of the foam core may cause misalignment. Therefore, it takes time and effort to correct the position of the foam core material, and this may lead to a decrease in production efficiency.

An object of the present invention is to provide a foam core material capable of improving production efficiency, a resin sandwich panel using the foam core material, and a method for manufacturing a resin sandwich panel.

The foam core material of the present invention is characterized in that it is formed in a flat plate shape and has projections that contact and support the inner surface of the cavity of the mold through the molten resin sheet.

A resin sandwich panel according to the present invention is characterized in that the above-described foamed core material is sandwiched between two sheets of the molten resin by welding the outer peripheral edges of the panels.

In the method of manufacturing the resin sandwich panel of the present invention, the panel is formed into a flat plate shape, and a plurality of projections are formed on one surface thereof so as to abut against the inner surface of the cavity of the first mold via the first molten resin sheet. a foam core preparation step of preparing a foam core having protrusions formed on the side surfaces of the convex portions so as to support the foam core, and a state in which the first molten resin sheet is shaped in the first mold a step of inserting the foam core material into the cavity of the first mold, and the first molten resin sheet and the second molten resin sheet using the first mold and the second mold. and a mold clamping step of welding the outer peripheral edge so as to sandwich the foamed core material.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the manufacturing method of the foam core material which can improve production efficiency, the resin sandwich panel using this foam core material, and the resin sandwich panel can be provided.

1 is a perspective view of a resin sandwich panel according to an embodiment of the present invention as viewed from above; FIG. 1 is a perspective view of a resin sandwich panel according to an embodiment of the present invention as viewed from below; FIG. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2 of the resin sandwich panel according to the embodiment of the present invention; It is the perspective view which looked at the foam core material which concerns on embodiment of this invention from the upper surface side. It is the perspective view which looked at the foam core material which concerns on embodiment of this invention from the lower surface side. 1 is a schematic diagram showing a molding apparatus for manufacturing a resin sandwich panel according to an embodiment of the present invention; FIG. FIG. 4 is a schematic diagram showing a state in which the mold of the molding apparatus for manufacturing the resin sandwich panel according to the embodiment of the present invention has adsorbed the first molten resin sheet. FIG. 4 is a schematic diagram showing a state in which a first molten resin sheet is formed in a first mold of a molding apparatus for manufacturing a resin sandwich panel according to an embodiment of the present invention; FIG. 4 is a schematic diagram showing a state in which a first molten resin sheet is shaped into a first mold of a molding apparatus for manufacturing a resin sandwich panel according to an embodiment of the present invention, and a foam core material is inserted. FIG. 3 is a schematic diagram showing a state in which the molds of the molding apparatus for manufacturing the resin sandwich panel according to the embodiment of the present invention are clamped.

Next, an embodiment of the present invention will be described based on the drawings. The resin sandwich panel 10 shown in FIGS. 1 and 2, which is formed in a substantially square flat plate shape, is a pallet on which cargo or the like is placed and transported together with the cargo by a forklift. As shown in FIG. 3, the resin sandwich panel 10 is formed by sandwiching and welding a foam core material 20 between two molten resin sheets, a first molten resin sheet 11 and a second molten resin sheet 12 . A plurality of protrusions 11a are formed on the first molten resin sheet 11 on the lower side of the resin sandwich panel 10 in FIG.

In the present embodiment, as shown in FIG. 2, a total of nine protrusions 11a are formed in three rows and three columns. The height of each convex portion 11a is formed to be the same. Each convex portion 11a is formed in a substantially truncated quadrangular pyramid shape. A chamfered surface 11a2 having a C-chamfer shape is formed at a connecting portion of the adjacent side surfaces 11a1 of each convex portion 11a (that is, a portion corresponding to the oblique side of the truncated quadrangular pyramid). Further, the convex portions 11a (for example, the convex portions 111) at the four corners are formed with chamfered portions 11a3 formed so that the top portions of the resin sandwich panel 10 on the corner side are scraped off. As for the size of the plurality of protrusions 11a (the size of the area of the upper surface and the lower surface), the protrusions 11a at the four corners (for example, the protrusions 111) are formed relatively large, and then the four protrusions 11a between the protrusions 11a at the four corners are formed. The portion 11a (for example, the convex portion 112) is large, and the central convex portion 11a is formed to be the smallest.

A predetermined interval is provided between the adjacent convex portions 11a, and the forks of a forklift can be inserted into the convex portions 11a. Further, on the surface of the first molten resin sheet 11, recesses 11b are formed between adjacent protrusions 11a (for example, protrusions 111 and 112) around the outer periphery. The recessed portion 11b serves as a gripping portion of the resin sandwich panel 10. As shown in FIG.

Further, four holes 11c are formed around the central protrusion 11a. The hole portion 11c is a hole formed corresponding to the through hole 23 of the foamed core material 20, which will be described later, and is used for air release during mold clamping. In addition, the hole 11c does not penetrate.

Further, as shown in FIG. 1, the surface of the second molten resin sheet 12 opposite to the first molten resin sheet 11 is a continuous flat surface. In addition, a parting line PL, along which the first molten resin sheet 11 and the second molten resin sheet 12 are aligned, is annularly formed on the outer periphery of the resin sandwich panel 10 .

The foam core material 20 inside the resin sandwich panel 10 is shown in FIGS. The foam core 20 shown in FIGS. 4 and 5 is the foam core 20 before molding (the foam core 20 after molding is in contact with the first molten resin sheet 11 and the second molten resin sheet 12). The portions to be welded are melted to form welded portions (for example, welded portions 20b2, 21e, and 21f) (see FIG. 3)).

The first surface 20a, which is one surface of the foamed core material 20 formed in a substantially flat plate shape, corresponds to the first molten resin sheet 11 of the resin sandwich panel 10, and the second surface 20b, which is the other surface, is the second molten resin. Corresponds to sheet 12 . The foam core material 20 is made of resin to which a foaming agent is added. Examples of the resin forming the foam core material 20 include polyolefins (eg, polypropylene, high-density polyethylene) that are homopolymers or copolymers of olefins such as ethylene, propylene, butene, isoprenepentene, and methylpentene, polyamides, and polystyrenes. , polyvinyl chloride, polyacrylonitrile, acrylic derivatives such as ethylene-ethyl acrylate copolymers, polycarbonates, vinyl acetate copolymers such as ethylene-vinyl acetate copolymers, ionomers, terpolymers such as ethylene-propylene-dienes, Acrylonitrile-styrene copolymer, ABS resin, polyphenylene oxide, polyacetal, phenol resin, polymethacrylimide, polyetherimide and the like. In addition, these may be used individually by 1 type, or may be used in mixture of 2 or more types. In particular, by using the same material for the foam core member 20, the first molten resin sheet 11, and the second molten resin sheet 12, they can be bonded by thermal welding without using a solvent or the like. The foam core material 20 may contain additives, and the additives include inorganic fillers such as silica, mica, talc, calcium carbonate, glass fiber, carbon fiber, plasticizers, stabilizers, colorants, Examples include antistatic agents, flame retardants, foaming agents, and the like.

As the foaming agent in this embodiment, any of physical foaming agents, chemical foaming agents, and mixtures thereof may be used. As physical blowing agents, inorganic physical blowing agents such as air, carbon dioxide gas, nitrogen gas, and water, organic physical blowing agents such as butane, pentane, hexane, dichloromethane, and dichloroethane, and supercritical fluids thereof are used. be able to. As the supercritical fluid, it is preferable to use carbon dioxide, nitrogen, or the like. Nitrogen has a critical temperature of 149.1 ° C. and a critical pressure of 3.4 MPa or more, and carbon dioxide has a critical temperature of 31 ° C. and a critical pressure of 7. .4 MPa or more.

As shown in FIG. 5, a convex portion 21 is formed on the first surface 20a. Since the convex portion 11a of the resin sandwich panel 10 described above is formed by the first molten resin sheet 11 being in close contact with the convex portion 21 of the foam core material 20, the convex portion 21 of the foam core material 20 is It is formed in substantially the same shape as the protrusion 11 a of the resin sandwich panel 10 . That is, the convex portion 21 of the foam core member 20 is formed in a substantially truncated quadrangular pyramid shape having side surfaces 21a and chamfered surfaces 21b (the convex portion 21 at the four corners is further chamfered 21c). The projections 21 of the foam core 20 have the same size and number as the projections 11 a of the resin sandwich panel 10 . However, as shown in FIG. 3, the eight convex portions 11a (for example, convex portions 211 and 212) arranged on the outer peripheral portion of the foam core material 20 have the outer side surfaces 21a that are inclined surfaces that are continuous at the same angle. (In the resin sandwich panel 10, an annular peripheral inclined surface 13 with different angles is formed). In this embodiment, the outer side surface 21a is formed as a continuous inclined surface at the same angle as an example of a preferred embodiment, but the inclined surface may be formed so that the angle of the inclined surface is slightly different depending on the part. Moreover, it is preferable that the size of the protrusions 21 of the foam core 20 is such that a gap 28 (see enlarged view A of FIG. 3) is formed between the protrusions 21 of the resin sandwich panel 10 and the protrusions 11a of the resin sandwich panel 10. be.

A protrusion 25 is formed on the side surface 21 a of the protrusion 21 of the foam core material 20 . A plurality of projecting portions 25 formed on each projecting portion 21 are projections that contact and support the inner surface of the cavity of the mold through the first molten resin sheet 11, as will be described later. The protrusion 25 is formed in a tapered shape with an inclined surface rising toward the base of the protrusion 21 . The protrusion 25 is formed with a width sufficiently narrower than the width of the side surface 21a on which it is formed. Protrusions 25 are formed on all four side surfaces 21a of the central protrusion 21, and protrusions 25 are formed on the inner surface (that is, other than the outer surface) of the side surfaces 21a of the other protrusions 21 formed on the edge side. A portion 25 is formed.

Further, recesses 22 are formed between adjacent protrusions 21 (for example, protrusions 211 and 212) around the outer periphery. The recess 11 b of the resin sandwich panel 10 described above is formed corresponding to the recess 22 .

The second surface 20b of the foam core material 20 is formed into a flat surface. Grooves 20b1 are formed in a grid pattern on the second surface 20b. On the other hand, four through holes 23 are formed in four directions around the central projection 21 . The through hole 23 is formed so that the hole diameter is reduced in several steps from the first surface 20a to the second surface 20b. The through hole 23 on the second surface 20b side is positioned at the intersection of the grooves 20b1 (see enlarged view B in FIG. 4). Further, the through-hole 23 on the first surface 20a side is formed with grooves 21d radially communicating with the through-hole 23 and branched to communicate with the protrusions 21 and the recesses 22 as well.

The resin sandwich panel 10 is formed by a molding device 60 shown in FIG. The molding device 60 has a known configuration. In the molding apparatus 60, two resin supply apparatuses 61 for molding molten resin sheets are arranged facing each other (a first resin supply apparatus 61A and a second resin supply apparatus 61B). A molten resin sheet 12 is formed. Molds 80 (first mold 81 and second mold 82 ) are arranged below the resin supply device 61 .

The resin supply device 61 includes a hopper 65 serving as a resin material supply port, and an extruder 66 that melts and kneads the material supplied from the hopper 65 by a screw that is connected to a hydraulic motor 68 and disposed inside. be provided. The extruder 66 is connected to an accumulator 70 having a plunger 72 , and the melted and kneaded resin material is sent from the extruder 66 to the accumulator 70 . The resin material is pressurized by the accumulator 70 and sent to the T-die 71, the die slit of the T-die 71 is opened at an appropriate timing, and the resin material is sent out by the roller 79 to form the first molten resin sheet 11 and the second molten resin sheet 11. A resin sheet 12 is formed.

The resin material charged into the hopper 65 is a thermoplastic resin such as polyolefin that is formed into pellets. Polyolefins include low density polyethylene, linear low density polyethylene, high density polyethylene, polypropylene, ethylene-propylene copolymers and mixtures thereof. Additives such as glass fibers, talc, and pigments may also be added to these.

In the cavity 81a of the first mold 81 of the mold 80, a plurality of recesses 81a1 are formed for forming the projections 11a of the resin sandwich panel 10 described above. A mold frame 83 is formed around the outer circumference of the first mold 81 . The formwork 83 moves toward the first molten resin sheet 11 and adsorbs the first molten resin sheet 11 . On the other hand, the first mold 81 is provided with a mold frame 83 and a vacuum pump (not shown) for decompressing the space in the first molten resin sheet 11 and the cavity 81 a of the first mold 81 .

Next, a method for manufacturing the resin sandwich panel 10 will be described with reference to FIGS.
Foam core material preparation step: The aforementioned foam core material 20 is prepared.
Material supply step: The first molten resin sheet 11 and the second molten resin sheet 12 are extruded from the first resin supply device 61A and the second resin supply device 61B, respectively (see FIG. 6). The first molten resin sheet 11 and the second molten resin sheet 12 are supplied between the molds 80 (between the first mold 81 and the second mold 82). The first molten resin sheet 11 and the second molten resin sheet 12 do not need to be molded at the same time, and the second molten resin sheet 12 may be molded immediately before the mold clamping step, which will be described later.

Shaping step: The mold 83 is moved toward the first molten resin sheet 11 and brought into contact with the sheet surface of the first molten resin sheet 11 (see FIG. 7). Then, the mold frame 83 and the first mold 81 are brought relatively close to each other, and the pressure in the space formed by the first molten resin sheet 11, the cavity 81a, and the mold frame 83 is reduced to move the first molten resin sheet 11 into the cavity. 81a (see FIG. 8).

Foam core inserting step: Between the material supply step and the shaping step, the foam core 20 supported by a robot hand or the like (not shown) is positioned outside the first molten resin sheet 11 so as to face the cavity 81a. (See Figure 8). Then, the foam core 20 is inserted into the cavity 81a of the first mold 81 while the first molten resin sheet 11 is formed in the first mold 81 (see FIG. 9). The foamed core 20 made of a foamed material melts at a portion in contact with the first molten resin sheet 11 in a high temperature state to form a welded portion where the foamed core 20 and the first molten resin sheet 11 are welded and connected. (For example, welded portions 21e and 21f (see FIG. 3)) are formed.

Mold clamping step: The second molten resin sheet 12 is positioned outside the foam core 20 (in other words, the second molten resin sheet is positioned between the cavity 82a of the second mold 82 and the foam core 20). 12), the first mold 81 and the second mold 82 (cavity 82a ) are brought relatively close to each other, and the mold is clamped until the annular pinch-off portions 81b and 82b come into contact with each other. In this manner, the first molten resin sheet 11 and the second molten resin sheet 12 are welded along the pinch-off portions 81b and 82b of the outer periphery so as to sandwich the foam core material 20 therebetween. At the portion where the foam core 20 and the second molten resin sheet 12 are in contact with each other, the foam core 20 is melted to form a welded portion 20b2 (see FIG. 3).

Here, in the step of inserting the foamed core material, the foamed core material 20 is melted by contacting the flat surface of the upper surface of the convex part 21a with the first molten resin sheet 11, thereby forming the welded part 21f and forming the first mold. 81 (cavity 81a). Then, in particular, a part of the projecting portion 25 (welding portion 21e in FIG. 3) of the side surface 21a located on the lower side (lower side in FIG. 6 etc.) with respect to the first mold 81a in the convex portion 21a is first melted. By coming into contact with the resin sheet 11, the foam core 20 is supported in contact with the inner surface of the cavity 81a. That is, conventionally, when the foam core material 20 is large, it may be displaced downward with respect to the first molten resin sheet 11 due to its own weight. Since it is supported by the portion 25, it is less likely that the foam core material 20 will be displaced due to its own weight. In this way, there is no need to correct the positional deviation of the foam core material 20, so the production efficiency of the resin sandwich panel 10 is improved. Furthermore, since the protrusion 25 is tapered, the amount of interference between the protrusion 25 and the first molten resin sheet 11 gradually increases when the foam core 20 is inserted. Therefore, it is possible to obtain a sufficient amount of interference while reducing problems such as the protrusion 25 breaking the first molten resin sheet 11 . In addition, as shown in the enlarged view A of FIG. 3, a gap 28 is formed above the protrusion 25 in FIG.

Also, the protrusion 25 is formed to have a sufficiently narrow width. Here, when the amount of interference between the side surface 21a of the convex portion 21 and the first molten resin sheet 11 is increased without providing the protrusion 25, the resistance between the foam core 20 and the first molten resin sheet 11 increases. This may cause the first molten resin sheet 11 to be displaced or torn, wrinkles to form on the surface of the first molten resin sheet 11 after molding, and the foam core 20 to be insufficiently inserted. . Therefore, even when the foam core 20 is inserted into the first mold 81, the first molten resin sheet 11 is less likely to break due to the protrusions 25 having a sufficiently narrow width.

Further, as shown in FIG. 3 , an outer peripheral space 16 is formed around the outer periphery of the foam core material 20 . The outer peripheral space 16 communicates with the grooves 21d and 20b1 on the flat plate surfaces (the first surface 20a and the second surface 20b) of the foam core material 20. As shown in FIG. Therefore, in the step of inserting the foam core material and the mold clamping step, the gap between the first molten resin sheet 11 and the first surface 20a of the foam core material 20 and between the second molten resin sheet 12 and the second surface of the foam core material 20 20 b can be released to the outer peripheral space 16 . Further, the first mold 81 is formed with a flow passage (not shown) for releasing air to the outside of the cavity 81a through the hole portion 11c. This flow path can also reduce air pockets.

Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments and can be implemented in various forms. For example, the protrusions 25 may be formed on a surface (for example, the lower surface) that can support the weight of the foam core 20 during molding. Moreover, although the projecting portion 25 is formed on the side surface 21a of the projecting portion 21, it can also be formed on the outer edge surface 26 (see FIG. 5) of the foam core member 20. FIG. Therefore, the projections 25 can be formed even on the flat foam core 20 on both sides where the projections 21 are not formed. In particular, when the protruding portion 25 is provided on the outer edge surface 26, it is preferable to form it only in a direction (for example, vertical direction) in which the weight of the foam core 20 can be supported during molding. If the projecting portion 25 is provided in a direction (for example, horizontal direction) in which the weight of the foam core material 20 cannot be supported, the projecting portion 25 may be caught on the molten resin sheet. Then, since the mold 83 may not be able to hold the molten resin sheet strongly, the molten resin sheet may be displaced together with the foam core material 20 . Further, the foam core member 20 of the present embodiment, which is formed in point symmetry, has a plurality of projections 25 to eliminate directionality when it is inserted into the first mold 81 . Moreover, although the protrusion 25 is formed in a tapered shape in the present embodiment, it is not limited to this, and the protrusion 25 can be formed in various shapes. In addition, although the projecting portion 25 is formed to have the same width, it is not limited to this, and can be formed so as to widen toward the base end portion, for example.

REFERENCE SIGNS LIST 10 resin sandwich panel 11 molten resin sheet 11 first molten resin sheet 11a convex portion 11a1 side surface 11a2 chamfered surface 11a3 chamfered portion 11b concave portion 11c hole 12 second molten resin sheet 16 outer peripheral space portion 20 foam core material 20a first Surface 20b Second surface 20b1 Groove portions 20b2, 21e, 21f Welding portion 21 Protruding portion 21a Side surface 21b Chamfered surface 21c Chamfered portion 21d Groove portion 22 Concave portion 23 Through hole 25 Protruding portion 26 Outer edge surface 28 Gap 60 Molding device 61 Resin supply device 61A First resin supply device 61B Second resin supply device 65 Hopper 66 Extruder 68 Hydraulic motor 70 Accumulator 71 T die 72 Plunger 79 Roller 80 Mold 81 First mold 81a, 82a Cavity 81a1 Concave portion 82 Second mold 81b, 82b Pinch-off portion 83 Formwork 111 Projection 112 Projection 211 Projection 212 Projection

Claims (6)

It is formed in the shape of a flat plate, and on one side , a convex portion having a plurality of flat side surfaces is formed, and through the molten resin sheet , it abuts against the flat inner surface of the mold cavity corresponding to the plurality of flat side surfaces. A foam core material characterized in that a protrusion that contacts and supports is formed on the side surface of the protrusion, and the protrusion is formed with a width sufficiently narrower than that of the side surface. 2. The foam core material according to claim 1, wherein the protrusion is tapered. 3. The foam core material according to claim 1, wherein a plurality of said convex portions are provided on said one surface. A sandwich panel made of resin, wherein the foamed core material according to any one of claims 1 to 3 is sandwiched between two molten resin sheets with their outer peripheral edges welded. 5. The resin sandwich panel according to claim 4, further comprising an outer peripheral space formed on the periphery of the foam core so as to communicate with the grid-shaped grooves formed on the flat plate surface of the foam core. . It is formed in a flat plate shape, and on one side , a plurality of convex portions having a plurality of flat side surfaces are formed, and a flat first mold corresponding to the plurality of flat side surfaces is formed via the first molten resin sheet. a foam core material preparation step of preparing a foam core material provided with protrusions formed on the side surfaces of each of the protrusions so as to abut against and support the inner surface of the cavity and having a width sufficiently narrower than that of the side surfaces; ,
a foam core material inserting step of inserting the foam core material into the cavity of the first mold in a state where the first molten resin sheet is shaped in the first mold;
a mold clamping step of welding the outer peripheral edge of the foam core material between the first molten resin sheet and the second molten resin sheet using the first mold and the second mold;
A method for manufacturing a resin sandwich panel, comprising:

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