JPH0235648B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a heat insulating box using a plastic film as an inner box, and its purpose is to embed a part of the plastic film in a foam heat insulating material to form a foam heat insulating material. The objective is to prevent the plastic film from peeling off from the surface.

Japanese Patent Publication No. 46-15833 discloses a method for manufacturing a heat insulating box using a plastic film as an inner box. According to this method, the reason for using a plastic film is that the foamed heat insulating material and the inner mold jig do not adhere to each other. The foam insulation material itself has a smooth surface, and the abrasion phenomenon on the surface has been eliminated. The advantage is that the body itself can be manufactured at low cost. However, if the surface of the foam insulation material is formed into a smooth surface, the adhesive strength between the plastic film and the foam insulation material will be weakened, and the plastic film will peel off from the foam insulation material due to friction caused by contraction and expansion of the foam insulation material. Therefore, the manufacturing method was not sufficient to use plastic film as the inner box.

The present invention improves these drawbacks, and embodiments thereof will be described below with reference to the drawings.

1 shown in FIG. 1 is an injection port 1a and an exhaust port 1b,
1b is a metal outer box, 2 is a bag-shaped plastic film serving as an inner box, 3 is an inner mold jig, and 4 is an opening 4a, 4 corresponding to the injection port and exhaust port.
b, 4b, the plastic film overlaps itself at appropriate places on the surface facing the inner surface of the outer box 1, and a plurality of fin pieces 2a, 2a extending in the direction of the outer box are formed, and holes are formed in the fin pieces. Through holes 2b, 2b are formed. This fin piece may be formed with double-sided adhesive 5 as a core to increase its strength, as shown in FIG. It is sufficient that the inner mold jig 3 is in an upright state when the inner mold jig 3 is covered with the plastic film 2. Further, the surface of the plastic film 2 facing the inner surface of the outer box 1 is preliminarily processed to have a rough surface 2c as shown in FIG. The rough surface 2c shown in FIG. 2A is formed at the same time as the film is formed, and the rough surface 2c' shown in FIG. 2B is formed by applying a powder such as ground glass after the film is formed.

Next, I will explain the manufacturing method of the insulation box.
As shown in FIG. 1, the inner mold jig 3 is covered with a plastic film 2, and in this state it is inserted into the outer box 1 to form a predetermined gap 7 between the inner surface of the outer box 1 and the plastic film 2. After that, an outer mold jig 4 is disposed on the outer surface of the outer box 1, and both the inner mold and outer mold jigs 3 and 4 are assembled. Then, a foaming stock solution such as hard polyurethane is injected into the gap 7 from the injection port 1a. When the foaming solution is injected, the plastic film 2 comes into close contact with the outer surface of the inner mold jig 3 due to the foaming pressure caused by the foaming action of the foaming solution, and the fin pieces 2
a, 2a are buried in the growing foamed heat insulating material 8 passing through the void 7 and the through holes 2b, 2b;
The air inside is discharged from the exhaust port 1 as the foam insulation material 8 grows.
b, pushed out from 1b. After foaming is completed, by removing both the inner mold and outer mold jigs 3 and 4, the third and fourth
The insulated box shown in the figure is completed.

According to such a method, when foaming, the fin pieces 2a, 2a
can be embedded in the foam insulation material 8, and the bonding area between the plastic film 2 and the foam insulation material 8 can be increased. Moreover, after the foam insulation material 8 has solidified, this insulation material can be embedded in the tips of the fin pieces 2a, 2a. Because it is connected in one direction among the front and back, top and bottom, and left and right directions by the through holes 2b and 2b between the outer box 1 and the outside,
The fixing force of the fin pieces 2a, 2a increases, and the foam insulation material 8
Even if a frictional phenomenon occurs due to contraction and expansion of the plastic film 2, the plastic film 2 will not peel off from the foamed heat insulating material 8, and its function as an inner box will not be impaired.
In addition, since the foaming pressure applied to the fin pieces 2a, 2a during the growth of the foam insulation material 8 can be weakened by the through holes 2b, 2b, the fin pieces 2b, 2b can be reliably buried in the foam insulation material 8, and the plastic film 2
It is possible to prevent the outer peripheral surface of the fin pieces 2a, 2a from overlapping with each other.

As described above, when a plastic film is used as an inner box, the present invention can reduce the foaming pressure of the foam insulation material applied to the fin pieces, firmly embed the fin pieces in the foam insulation material, and eliminate foaming defects. Since the fin pieces are formed using the plastic film itself, the number of parts is small and processing is easy, making it possible to provide an inexpensive heat insulating box.

[Brief explanation of drawings]

The drawings show an embodiment of the method for manufacturing a heat insulating box according to the present invention, FIG. 1 is a longitudinal sectional view showing the foaming process, and FIGS. 2A and 2B are enlarged views showing different embodiments from FIG. 1A.
3 is a partially cutaway perspective view of the heat insulating box, FIG. 4 is a sectional view taken along line BB' in FIG. 3, and FIG. 5 is a perspective view of the inner box. 1...Outer box, 2...Plastic film, 2
a, 2a...fin piece, 2b, 2b...through hole, 8...
...foam insulation.

Claims (1)

[Claims] 1 A plurality of fin pieces are formed at appropriate positions on the surface facing the outer box and stand up on the outer box side, and a box-shaped plastic film with through holes formed in the fin pieces is placed on the inner surface side of the outer box. A foaming solution is poured between the plastic film and the outer box, and the foaming pressure is used to form the plastic film into the shape of an inner box, and the foam insulation is passed through the holes and the fin pieces are embedded within the foam insulation. A method of manufacturing a heat insulating box body characterized by: