JPH0857947A - Manufacture of foamed resin vessel - Google Patents

Abstract

PURPOSE: To obtain a foamed resin vessel of a low stacking height merely by opening a vacuum guide passage for sucking and fixing a foamed sheet in a conventional mold. CONSTITUTION: In the case of manufacturing a vessel having a sidewall provided at the periphery at an obtuse angle to a bottom surface in a molding space 6 formed between a female mold 4 and a male mold 5 after a synthetic resin foamed sheet 1 is thermally plasticized, the sheet 1 is fixed by vacuum in a nonmolding part 7 between the space 6 and the space 6 of the female mold 4 and between the space 6 and the end of the female mold, and then the mold 5 is engaged within the mold 4 and molded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a foamed resin container, and more particularly to a method for producing a so-called low-stacked foamed resin container which has a low stacking height when a large number are stacked. .

[0002]

2. Description of the Related Art Today, a polystyrene foam sheet press-molded is widely used as a container for storing foods and the like.

[0003]

However, as shown in FIG. 4, the conventional foamed resin container has a larger thickness than the non-foamed plastic container, the paper container, and the like, and the bottom portion of the container 11 has a large thickness. 12 and the side wall 13 have the same thickness. Since such foamed resin containers are usually transported, stored and used in a stacked state, the stacking height becomes extremely large and the number of stacked units per unit space volume becomes smaller, resulting in transport efficiency and storage efficiency. Is low, and it is necessary to refill and stack containers frequently when using,
It includes the problem of poor workability.

In order to solve such a problem, Japanese Patent Publication No. 63-63
Japanese Patent No. 65491 discloses a method of reducing the side wall thickness by limiting the side wall thickness of the container to the maximum free foam thickness achieved by in-mold foaming at the mold surface. ing. However, in this method, the conventional mold cannot be used, and the mold must be newly recreated, which is extremely expensive.

The present invention provides a low-stack container made of foamed resin by reducing the thickness of the side wall using a conventional mold.

[0006]

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have found that, during molding, a foam sheet is formed between the molding spaces of female molds and between the molding space and female edge. By fixing the non-molding part between and with vacuum, by closing both molds, and further by fixing the foamed sheet to the bottom forming part of the male mold with vacuum, by closing both molds, The present invention has been completed by finding that the side wall of the container can be made thin and a low-stack container can be obtained.

That is, according to the first aspect of the present invention, after heat-plasticizing a synthetic resin foam sheet, the synthetic resin foam sheet is provided at an obtuse angle with respect to a bottom surface in a molding space defined between a female mold and a male mold. In manufacturing a container having a side wall, after the foamed sheet is vacuum-fixed to a non-molding portion between the molding space of the female mold and between the molding space and the edge of the female mold, A second aspect of the present invention is a method for producing a foamed resin container, which comprises molding the male mold by fitting the male mold into a female mold. In manufacturing a container having a side wall formed at an obtuse angle with respect to the bottom surface in a molding space defined between the mold and the mold, the foam sheet is provided between the molding space of the female mold and the molding space. After fixing by vacuum to the non-molding part between the molding space and the female mold edge, the male mold bottom forming part The foamed sheet was fixed by a vacuum, thereafter, it is an each content a method for manufacturing a female mating allowed to foam the resin vessel.

[0008]

The container side wall portion is obtained by fixing the foamed sheet in a non-molding portion between the molding space of the female mold and the molding space and between the molding space and the edge of the female mold with a vacuum and fitting the foamed sheet with the male mold. Since the foamed sheet of the portion corresponding to is molded in an expanded state, a container having a small side wall thickness can be obtained. Further, when fitting with the male mold, the foamed sheet fixed in vacuum to the non-molded portion of the female mold is further fixed in vacuum to the container bottom forming portion of the male mold and fitted into the female mold, thereby foaming. The part of the sheet corresponding to the bottom of the container does not extend while being fixed, and only the part corresponding to the side wall of the foamed sheet is molded in an expanded state, so that the side wall of the container is more reliably thinned. Is obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings showing the embodiments. FIG. 1 shows a manufacturing apparatus used in the present invention.
First, the synthetic resin foam sheet 1 is heated and plasticized by the heating device 2. The heat-plasticized foam sheet 1 is introduced into the molding device 3.

The molding device 3 comprises a female die 4 and a male die 5,
The female die 4 has a molding space 6 and guides a vacuum to a non-molding portion (a portion corresponding to a burr or a groove of a molded product) 7 between adjacent molding spaces and between the molding space and the edge of the female mold. The passage 8 is drilled.

The foamed sheet 1 introduced into the molding apparatus is sucked and fixed on the surface of the non-molded portion 7 by drawing a vacuum through the vacuum guide 8 while being in contact with the surface of the female mold 4.
Next, the male mold 5 is fitted to the female mold 4 to confine the foam sheet 1 in the molding space defined by both molds to form a container in the shape of the molding space.

At this time, the foamed sheet 1 has the non-molded portion 7
Since it is placed and fixed by suction, the foamed sheet of the portion corresponding to the side wall of the container is molded in a stretched state,
As a result, as shown in FIG. 3, a container 13 having a side wall 13 thinner than the bottom 12 is obtained.

FIG. 2 shows another example of the manufacturing apparatus used in the present invention, in which the container bottom portion forming portion 9 of the male die 5 is also provided with a vacuum conduit 10. In order to manufacture a container using the above apparatus, first, the foamed sheet 1 is heated and plasticized by the heating device 2, then introduced into the molding device 3, and vacuumed through the vacuum passage 8 while being in contact with the surface of the female mold 4. 1 to the position where the foamed sheet 1 is sucked and fixed to the surface of the non-molded portion 7.
It is similar to the case of.

Next, the male die 5 is fitted to the female die. At this time, the container bottom molding portion 9 of the male die 5 is brought into contact with the foamed sheet 1 sucked and fixed to the female die 4 to form a vacuum. The foam sheet 1 is suction-fixed to the surface of the container bottom molding portion 9 by drawing a vacuum through the guide channel 10.

In the state as described above, the male die 5 is fitted to the female die 4, and the foamed sheet 1 is placed in the molding space defined by the two dies.
To form a container in the shape of the molding space.

In this case, since the foamed sheet 1 is suction-fixed to the non-molding portion 7 of the female mold 4 and also to the container-bottom molding portion 9 of the male mold 5, it can be moved freely. The foamed sheet 1 of the portion corresponding to the side wall is formed in an expanded state. Thus, as shown in FIG. 3, the side wall 1
A container 11 in which 3 is thinner than the bottom 12 is obtained.

As the synthetic resin foam sheet used in the present invention, a polystyrene resin foam sheet is preferable from the viewpoint of good moldability and appropriate rigidity. As the polystyrene resin foam sheet, a foam polystyrene sheet, a foam sheet of a copolymer resin with butadiene mainly containing styrene, methyl methacrylate, etc., a foam sheet of a mixed resin of polystyrene and polyphenylene ether, and a polystyrene resin foam sheet thereof. A film made of polystyrene, high-impact polystyrene, polyethylene or the like on one side or both sides, or a composite sheet in which a film made of a gas or moisture barrier ethylene-vinyl alcohol copolymer, vinylidene chloride, polyester, polyamide or the like is laminated. To be

[0018]

As described above, according to the present invention, a low-stack foamed resin container can be economically and economically provided by simply forming a vacuum conduit for suction fixing a foamed sheet in a conventional mold. It can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of an apparatus used in the present invention.

FIG. 2 is a schematic view showing another example of the apparatus used in the present invention.

FIG. 3 is a cross-sectional view of a foamed resin container obtained by the manufacturing method of the present invention.

FIG. 4 is a cross-sectional view of a conventional foamed resin container.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Synthetic resin foamed sheet 2 Heating device 3 Molding device 4 Female mold 5 Male mold 6 Molding space 7 Female non-molding part 8 Vacuum conduit 9 Male container bottom molding part 10 Vacuum conduit

Claims (3)

[Claims] 1. A container having a side wall formed at an obtuse angle with respect to a bottom surface in a molding space defined between a female mold and a male mold after heat-plasticizing a synthetic resin foam sheet. In doing so, after fixing the foam sheet to the non-molding portion between the molding space of the female mold and the molding space and between the molding space and the female mold edge by vacuum, the male mold is placed in the female mold. A method for producing a foamed resin container, characterized in that: 2. A container having a side wall formed at an obtuse angle with respect to a bottom surface in a molding space defined between a female mold and a male mold after heat-plasticizing a synthetic resin foam sheet. In doing so, after fixing the foamed sheet to the non-molded portion between the molding space of the female mold and the molding space and between the molding space and the female mold edge by vacuum, further on the bottom forming portion of the male mold. The manufacturing method according to claim 1, wherein the foamed sheet is fixed by vacuum and then fitted with a female mold. 3. The method according to claim 1, wherein the synthetic resin foam is a polystyrene resin foam sheet.