JPH02180176A - Heat-insulating box made of plastic form and its manufacture - Google Patents

Abstract

PURPOSE:To reduce transportation cost, improve appearance and obtain necessary strength with heat-insulating capacity by a method wherein a box is made of hollow side walls and bottom walls and formed in a foldable shape while the wall hollow part of the shape is filled with a heat-insulating material made of plastic foam. CONSTITUTION:To manufacture a box B from a developed pattern, F, after a connecting piece 13 of an front outer side wall 3a is adhered to a left side wall 5a to assemble in a parallelopipe, both front and back inner side plates 3b,4b are folded inward, stop pieces 14 on both sides are adhered to right and left outer side plates 5b,6b and double side walls 3,4 having thickness approximately equal to narrow width of an interval piece 10 are formed. Then, both right and left inner plates 5b,6b are folded inward, both flaps 3d,6d are overlaid and pasted, and right and left side walls 5,6 having a hollow part 21 are assembled. With a box placed upside down, that is, a bottom facing upward, in a state that bottom flaps 3c,4c,5c,6c opened, foaming agent is poured into the hollow parts 20,21 of the side walls 3,4,5,6 then blown flatly against a joint part of bottom upper flaps 3d,4d, the bottom lower flaps 3c,4c,5c,6c are overlaid and to have them secured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a plastic foam tray heating box suitable for transporting articles while keeping them cool or warm, and a method for manufacturing the same.

[Conventional technology]

Traditionally, plastic foam insulation boxes are mainly made of Styrofoam, with the body and lid integrally molded, and are lightweight and have excellent insulation properties, making them ideal for transporting fresh fish, fresh vegetables, fresh fruits, etc. is used very often.

For its manufacture, upper and lower molds are used in a plastic factory, and a plastic liquid is injected together with a foaming agent between the upper and lower molds to perform foam molding.

The heat insulating properties of plastic foam are highest at a certain density range, and the heat insulating properties tend to decrease as the density increases or decreases beyond that range. By the way, Figure 1 shows the relationship between the thermal conductivity and density of hard urethane foam, and it shows that the density is about 35 kg/rn.
'The insulation property shows the highest value.

[Problem to be solved by the invention]

Conventional plastic foam insulation boxes are manufactured at a factory, so they must be transported from the factory to the site of use, but this involves transporting the empty box, which is especially bulky between the body and the lid. However, it is inevitable that transportation costs will be high, and as a result, factories will be located near consumption areas, resulting in higher production costs.

In addition, since the bare skin of the plastic foam is exposed on the outer surface, it is rough and lacks beauty, and since ink does not adhere to it, it is not possible to enhance the appearance by printing.

Furthermore, as mentioned above, plastic foam.

Although plastic foam has an optimal density range for insulation, it is difficult to obtain the best insulation ability with a single plastic foam because the density range is limited due to the need to obtain appropriate strength in relation to this density. There were also problems.

In view of the above-mentioned circumstances, this invention was developed by assembling on-site foaming, which reduces transportation costs from the factory to the site, improves the beauty of the product due to the appropriate printing quality, and provides the best results. The object of the present invention is to provide a heat insulating box made of plastic foam that provides the necessary strength with heat insulating properties, and a method for manufacturing the same.

[Means to solve the problem]

To achieve the above object, the insulating box of the present invention has a body formed of hollow side walls and a bottom wall that can be folded flat, and the hollow part of the wall of the body is filled with a plastic foam insulation material. It is.

In addition, the manufacturing method for the insulation box involves configuring the prototype of the body, which will become the skin layer of the body, so that hollow side walls and bottom walls are formed, transporting the body in a flat folded state to the site, and placing the body in the gA field. As the figure is assembled, plastic is foamed and injected into the hollow part of the wall.

[For production]

According to the insulating box configured as described above, the body can be folded flat, so transportation cost can be reduced by transporting it to the site of use in the folded state. Because it is the material of the figure,
By using a material to which ink easily adheres, it is possible to print on the outer surface in an attractive manner.

In addition, since the plastic is injected into the body and foamed on-site, it is possible to select the appropriate foaming density depending on the items to be stored in the box.

Since it is reinforced by the body, the appropriate density of the plastic foam provides the highest degree of insulation.

Further, according to the method for manufacturing a heat insulation box configured as described above, the heat insulation box can be effectively manufactured.

Note that examples of the material for the body include paper, plastic, metal, and the like.

The structure and manufacturing method of the present invention can also be applied to the lid, but even if it is a completed structure, it is close to flat and can be stacked and transported relatively compactly.
We do not particularly care about its structure.

〔Example〕

Next, an embodiment of this invention will be described based on the drawings.

The stage heating box consists of body B and iL. Figures 2 to 4 show an example of body figure 1 and figure 2 assembled using relatively thin cardboard.
are assembled using a single unfolding mold F, but since they have the same assembly structure, illustration of the unfolding mold in figure 2 is omitted.

The deployable type F has both front and rear side plates 3a, 4a and left and right outer plates 5.
a, 6a are arranged laterally, and bottom lower flaps 3c, 4C15C16C are protruded from the lower ends of each. In addition, inner plates 3b, 4b, 5 are provided at the upper end via folded spacing pieces 10.
b, 6b are provided protrudingly, and the protruding dimension h2 is the outer plate 3a,
It is formed to be slightly shorter than the height dimension h1 of 4a, 5a, and 6a.

Furthermore, bottom upper flaps 3d, 4d, 5d, and 6d are protruded from the inner plates 3b, 4b, 5b, and 6b, one of which
The front and rear bottom upper flaps 3d, 4d are provided with notches 11.11 on both sides of the tip, and a hooking piece 12.13 is provided protruding from the tip. In addition, the left and right bottom upper flaps 5d and 6d are 5
It is formed to cover the entire bottom of the box.

A connecting piece 13 that is glued to the inside of the left outer plate 5a is provided at the end of the front and rear outer plates 3a, and a stopper that is glued to the inner surfaces of the left and right outer plates 5a and 5b is provided on both ends of the front and rear inner plates 3b and 4b. The piece 14.14 is provided protrudingly.

Among the engaging pieces 12 and 13, the front engaging piece 12 is provided with r<J-shaped notches 17a, 17a on both left and right sides of the central part, thereby forming the central part as a male piece 15,
The rear hooking piece 13 is provided with a female notch 16 in the center into which the male piece 15 is inserted, and its side edges 17b, 17b are formed in a "<" shape opposite to the notch 17a of the male piece 15. be. This allows the hooks of both hooking pieces 12 and 13 to be joined together.

When manufacturing the body B from the development type F above.

First, after assembling the connecting piece 13 of the anterolateral plate 3a to the left outer plate 5a into a rectangular tube shape by gluing it, the front and rear inner side plates 3b and 4b are folded inward, and the retaining pieces 14.1 on both sides are assembled.
4 to the left and right outer plates 5b, 6b, a double side wall 3.4 having a thickness equal to the width of the spacing piece 10 is formed. This side wall hollow 20 is held in place by the width of this spacing piece 10 and by the fastening of the stop pieces 14,14. Also, the two bottom upper flaps 3d and 4d are connected by the hooks of the hooks 12 and 13.

Next, the left and right side walls 5.6 having the hollow portion 21 are assembled by folding the left and right circumferential inner plates 5b, 6b inward, overlapping the flaps 5d, 6d, and gluing them together. Also, this stabilizes the bottom internally, so next time, as shown in Figure 3, turn the box upside down, with the bottom facing up, and open the lower bottom flaps 3c, 4c, 5c, and 6c. In this state, the foaming gun G injects the plastic together with the foaming agent.

For this injection operation, first the hollow part 20.21 of the side wall 3.4.56 is injected, and then the bottom upper flap 3d, 4
Spray it evenly onto the combination d, cover it with the lower bottom flaps 3c, 4c, 5c, and 6c, and fix the overlapped flaps with adhesive.

Now, the body B is constructed in which the hollow part 20.21 of the side wall 3.4.5.6 and the hollow part 22 of the bottom wall 7 are continuously filled with the plastic foam insulation material g. Insert the rectangular cylindrical engagement plate 9 made by folding a corrugated board into quarters,
By inserting the lid into it, body B is covered with a lid.

Polyurethane was used as the plastic to be injected.

Polyurethane foam has a high closed cell ratio and
Because each bubble can be filled with a gas such as carbon dioxide or Freon gas, which has a lower thermal conductivity than ordinary air, it exhibits extremely excellent heat and cold retention properties.

In addition to its heat-insulating properties, it also has self-adhesive properties that allow it to bond to other materials without adhesives, as well as excellent water and chemical resistance.

Regarding self-adhesiveness, it can be strongly adhered to paper, metal plywood, etc. by directly foaming on the surface, so it can be assembled very strongly.

Regarding water resistance, if the insulation material absorbs water or air, the insulation effect will decrease, but since it has a closed cell structure, it has strong resistance to water and water vapor infiltration, and the insulation effect will hardly change.

Further, as shown in FIG. 1, in the case of hard urethane foam, the thermal conductivity becomes minimum when the density is between 30 and 40 kg/rn', so the filling was performed so that the density falls within this range. However, due to the reinforcement of the cardboard material in body style 1 and style 2,
It showed the same high strength as the high-density case in terms of compressive strength and bursting strength.

Further, from the corrugated board factory to the site of use, the containers can be stacked and transported in large quantities in the unfolded form F shown in FIG.

When it is disposed of as a used product, it is incinerated, but since the combustion of the plastic foam is suppressed by the cardboard, the incinerator is not damaged by high heat compared to when the entire product is made of plastic foam.

By printing a pattern on the outer surface of body 1 and 2 in the expanded state F, it was possible to greatly improve the appearance of the outer surface of the heat insulating box with the pattern (not shown).

In this case, the outer surface of the cardboard can be laminated with a plastic film.

By printing on the film, it is also possible to display designs with excellent cosmetic properties.

[Other Examples]

FIG. 5 shows another embodiment, in which body figure 1 and figure 2 are formed hollow by foldable flexible plastic film, injection holes 25 are partially provided, and injection holes 25 By injecting and foaming plastic foam into the hollow portions 20 and 22, the inside is filled with the heat insulating material 8.

〔Effect of the invention〕

As explained above, according to the present invention, the body is manufactured in a foldable manner at the factory and transported to the site of use in the folded state, which is suitable for mass transportation and has good transportation economy, reducing freight costs. Even with plastic foam rings, the appearance can be enhanced by printing on the body. Furthermore, since it is reinforced depending on the person's body shape, it is easy to obtain the necessary strength, and it is possible to select the appropriate foam density without any problems in terms of strength. It has a positive effect.

Furthermore, since the amount of plastic foam material is relatively small, no harmful gas is generated even when incinerated, and the incineration part is not damaged much.

[Brief explanation of the drawing]

Fig. 1 is a reference diagram showing the relationship between thermal conductivity and density of hard urethane foam in a table, Figs. 2 to 4 show an embodiment of the present invention, and Fig. FIG. 3 is a perspective view showing the procedure for injection foaming of plastic foam, and FIG. 4 is a partially cutaway perspective view of the heat insulating box. FIG. 5 is a longitudinal sectional view showing another embodiment.

Claims (1)

[Scope of Claims] 1) A plastic foam product comprising a hollow side wall and a bottom wall to form a body that can be folded flat, and a hollow part of the wall of the body is filled with a plastic foam heat insulating material. insulation box. 2) Construct the prototype of the body that will become the cortical members of the body so that hollow side walls and bottom walls are created, transport the body in a flat folded state to the site, assemble the body at the site, and remove the hollow walls. A method for manufacturing a plastic multi-tiered heating box, characterized by injecting plastic into the part while foaming it.