JPH1148320A - Hollow double wall molding with heat insulation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a hollow double wall molding with a heat insulation material filled in the hollow part by only blow molding process. SOLUTION: The housing panel 1 being a hollow double wall molding is formed by blow molding a thermoplastic synthetic resin. At blow molding, a heat insulation material 7 containing air in the interior side is hermetically sealed into a hollow part 4 defined by the opposite front wall 2 and rear wall 3. The heat insulation material 7 having air contained in the interior side is formed into a mat by collecting synthetic fibers such as polyester fibers or the like with crimps.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a hollow double-walled molded article obtained by blow molding a thermoplastic synthetic resin,
The present invention relates to a hollow double-walled molded product having a heat insulating property in which a heat insulating material containing air is sealed in a hollow portion in a dense state.

[0002]

2. Description of the Related Art A hollow double-walled molded product obtained by blow molding a thermoplastic synthetic resin, in which a hollow portion is filled with a heat insulating material, is disclosed in JP-A-63-188030 or JP-A-Hei. -239869.

[0003]

According to the method disclosed in Japanese Patent Application Laid-Open No. 63-188030, after the blow molding, plastic granules containing an easily volatile liquid are injected into a hollow portion, and By foaming the pre-foamed and volume-reduced granules in the hollow portion, a hollow double-walled molded product having a heat insulating property filled with a foam heat insulating material in the hollow portion, the volume of the pre-foamed granules is reduced. It takes time to restore, and the manufacturing process from blow molding to obtaining the product requires a long time.

[0004] Further, Japanese Unexamined Patent Publication No. Hei 5-239869 discloses that a hollow double-walled molded product has a hollow portion.
Since it is filled with polyolefin resin particles that have been completely expanded, it is difficult to fill the foamed material into the hollow portion in the case of a thin molded product such as a panel, and the foamed material is filled after blow molding. Therefore, similarly to the above-mentioned example, a long time is required for a manufacturing process from blow molding to obtaining a product.

In view of the above, the present invention has been made to solve the above-mentioned problem. At the time of blow molding, a heat insulating material containing air is densely filled in a hollow portion between a facing front wall and a back wall. By enclosing in a state, it is possible to obtain a hollow double-walled molded product having a hollow portion filled with a heat insulating material only by a blow molding process, and a molded product in which the hollow portion is a narrow space such as a panel. Another object of the present invention is to provide a hollow double-walled molded product having heat insulation properties, which can be easily manufactured.

[0006]

In order to achieve the above object, a heat-insulating hollow double-walled product according to the present invention is provided.
A hollow double-walled molded product obtained by blow-molding a thermoplastic synthetic resin. During blow molding, a heat-insulating material containing air inside the hollow portion between the opposed front and back walls is in a dense state. It is characterized by being contained in

In the present invention, it is preferable that the heat-insulating material containing air therein is a mat made by gathering synthetic fibers such as crimped polyester fibers.

[0008]

FIG. 1 is a partially cutaway perspective view of a housing panel which is an example of a heat-insulating hollow double-walled molded product according to the present invention, and FIG. 2 shows a blow molding mode of the housing panel of FIG. FIG. 3 is a cross-sectional view before the mold clamping, and FIG. 3 is a cross-sectional view showing a state after the mold clamping from the state of FIG. 2.

In FIG. 1, a housing panel 1 has a hollow double-walled structure including a front wall 2 and a back wall 3.
A hollow portion 4 is provided between the front wall 2 and the back wall 3, and the peripheral end surfaces 5 of the front wall 2 and the back wall 3 are welded to each other and integrated. Reference numeral 6 denotes a parting line, which is a welded portion generated at a pinch-off portion of the mold during blow molding. Inside the hollow portion 4 of the housing panel 1, a heat insulating material 7 containing air therein is provided.
The space is filled densely to fill the space.

The air-containing heat insulating material 7 is made of a thermoplastic resin having heat resistance, that is, a foam made of polyethylene, polystyrene, polypropylene, polyester, or the like, or a thermosetting resin, that is, polyurethane, phenol resin, or the like. Or a synthetic fiber such as a crimped polyester fiber formed in a mat shape. As described above, since the heat insulating material 7 has a mat shape, it has a large number of air bubbles therein, and has excellent heat insulating properties. The crimp is shrinkage formed by a method such as passing synthetic fibers between heated gears.

The housing panel 1 shown in FIG. 1 is blow-molded in the manner shown in FIGS. As shown in FIG. 2, a heat insulating material 7 is arranged between a pair of molds 8, 8, and two sheet-like parisons 10, 10 are pushed from an extrusion head 9 so that the heat insulating material 7 is sandwiched therebetween. Extrude between eight. Then
As shown in FIG. 3, the housings 1 are formed by clamping the molds 8, 8, and introducing a pressurized fluid into the closed parisons 10, 10 to perform blow molding. Then, the heat insulating material 7 is densely filled in the hollow portion 4 so as to fill the hollow portion 4. The parison extruded from the extrusion head 9 may be flat or cylindrical depending on the shape of the molded product.

As shown in FIG. 2, the heat insulating material 7 is disposed between the molds 8 by suspending the suspension member 11 from the extrusion head 9. The suspension member 11 is a thin plate made of the same resin as the parisons 10, 10, or a string-shaped piece of cloth or the like.

If the heat insulating material 7 containing air therein has a volume slightly larger than the volume of the hollow portion 4 in a non-pressurized state, the hollow portion 4 of the blow molded housing panel 1 can be formed.
The heat insulating material 7 can be completely filled without any gaps. Further, by changing the amount of air contained in the heat insulating material 7, even when the shape of the molded product is not monotonous, the heat insulating material conforms well to the shape in the hollow portion of the molded product at the time of blow molding. The heat insulating material 7 can be filled.

Since the housing panel 1 according to the present invention is manufactured only by the blow molding process, there is no need for a separate process of filling the hollow portion with the foam material unlike the conventional molded product. For this reason, according to the present invention, the molding cycle of the housing panel 1 can be shortened.

The housing panel 1 according to the present invention has a hollow portion 4 in which synthetic fibers such as polyester fibers having crimps are gathered and densely filled with a mat-like heat insulating material 7 having a large number of air bubbles therein. Therefore, the convection of air in the hollow portion 4 is suppressed, and the heat insulation effect from the outside is large.
Further, since the heat insulating material 7 is enclosed in the hollow portion 4 and is in a mat shape having a large number of air bubbles,
Inside, the wave energy from the outside can be effectively attenuated, and the housing panel 1 is excellent in sound insulation.

In the present invention, if the heat insulating material 7 is made of the same resin as the housing panel 1, it becomes possible to pelletize the housing panel 1 when disposing of it.
Easy to recycle. In the present invention, as the heat insulating material 7, a waste material of a foamed foam material such as polyurethane, a mat for a mattress, a cushion material for a vehicle seat, or a mat formed by crimping synthetic fibers can be used.

[0017]

According to the present invention, during blow molding, a heat insulating material containing air therein is tightly sealed in a hollow portion between the facing front wall and back wall, so that the heat insulating material is filled in the hollow portion. Can be obtained only by the blow molding process, and even a molded product having a narrow hollow space such as a panel can be easily manufactured. A hollow double-walled molded product having heat insulation properties can be obtained.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of a housing panel as an example of a hollow double-walled molded product having heat insulating properties according to the present invention.

FIG. 2 is a cross-sectional view of the housing panel of FIG.

FIG. 3 is a cross-sectional view showing a state after mold clamping from the state of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing panel 2 Front wall 3 Back wall 4 Hollow part 5 Peripheral end surface 6 Parting line 7 Insulation material 8,8 A pair of dies 9 Extrusion head 10,10 Sheet-shaped parison 11 Hanging member

Claims (2)

[Claims] 1. A hollow double-walled molded product obtained by blow-molding a thermoplastic synthetic resin, wherein air is contained in a hollow portion between a facing front wall and a back wall during blow molding. A hollow double-walled molded article having heat insulating properties, wherein the heat insulating material is sealed in a dense state. 2. The heat insulating hollow double wall according to claim 1, wherein the heat-insulating material containing air therein is formed by matting synthetic fibers such as polyester fibers having crimps. Molding.