JPH0360663B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a synthetic resin foam molded product for packaging, and it is an industrial method for manufacturing a foam molded product in which characters, figures, or patterns are embodied on the outer peripheral surface of the packaging molded product itself. The purpose is to provide this information advantageously.

Conventionally, when packaging the contents of sewing machines, outboard motors, etc. using this type of synthetic resin foam for packaging, after packaging, the outer periphery of the foam was further printed with letters, figures, or patterns such as cardboard or paper. Usually, packaging products are covered with a film or sheet to improve the appearance, advertising, or product image of the packaged product. However, in this case, it is very time-consuming and the cost of auxiliary materials such as cardboard is also high.

The present invention solves the above-mentioned drawbacks all at once, and performs initial foaming by filling pre-expanded beads made of synthetic resin such as polystyrene or polyolefin into a single mold consisting of a fixed part and a moving part. After performing molding to form concave or convex portions having the same shape as desired characters, figures, or patterns on the surface of the molded product, the moving part of the single mold is opened to create a gap that fits the concave or convex portions. Next, the gap is filled with beads having a different expansion ratio or color from the first time, and the movable part mold is returned to its original position, and two-layer molding is performed in the second foam molding to produce a foam molded product. The object of the present invention is to provide a method for producing a synthetic resin foam molded product for packaging, which is characterized by embodying characters, figures, or patterns on itself.

Two-layer molding as referred to in the present invention means that a mold is first filled with pre-foamed beads using a mold in which concave or convex portions corresponding to desired characters, figures, or patterns are provided in desired parts of the fixed part of the mold. After the first heat forming,
The moving part in the mold is opened to create a desired gap, and the gap is filled with pre-foamed beads having a different expansion ratio, color, etc. from the initial one. At this time, the size of the gap caused by opening the mold is smaller than the depth of the concave or convex part formed at the first time, or even if it is larger, the gap formed between the upper end of the concave or convex part, the mold, and the edge. The gap must be such that the beads will not leak out. Next, the movable part mold is returned to its original position, the mold is tightened, and a second molding is performed by normal heating or by heating only one side. In this way, desired characters, figures, or patterns are realized on the foamed molded product itself, so that it appears to be embossed. In particular, it is preferable to use beads with a lower foaming degree than those used for the first filling as the second filling beads, as they have a particularly beautiful appearance and are strong.

As mentioned above, the synthetic resin foam molded product for packaging, which is formed by two-layer molding using the manufacturing method of the invention, clearly embodies characters, figures, or patterns on its surface.
The appearance is beautiful enough, so like traditional foam,
This invention has great practical value since it is not necessary to further cover the outer peripheral surface with cardboard paper or the like printed with letters, figures, patterns, etc., and the foamed molded product can be used as it is as a packaging material. Note that the foamed molded product produced according to the present invention may be further packed and packaged with other paper, tape, etc. before use.

As the pre-foamed beads, polystyrene-based or polyolefin-based synthetic resin pre-beads are preferably used.

Examples will be specifically described below with reference to FIG. 2.

Example 1 Figure 2 shows the "mold structure" used for producing the molded object of the present application, the attachment of the feeder of the foamed beads, and "cross-sectional views of the product molded object" 1 and 2 manufactured with this mold, and also In the "implementation process" of molding, it is a diagram showing a method of feeding high foam beads and low foam beads from a feeder in the order of 1 → 2 → 3 and a heat molding method. The "mold" for the "product sectional views" 1 and 2 in FIG. 2 will be explained. In the case of mold structure 1, a feeder is attached to the convex part of the product on the fixed part side of the mold, which consists of a fixed part and a moving part, and one of the feeders is attached to a high magnification bead (hereinafter referred to as a polystyrene-based spare) of the molded product body. (using foam beads). In the figure, the top feeder is set for the main body of the molded product. The two feeders below are low magnification bead introduction feeders for two layers. In the case of "mold structure" 2, it is set at the top of the mold fixing part side as a feeder for the molded product body. That is, it is a high magnification bead introduction feeder. The other three feeders are set in the recesses. This is a feeder for introducing low-magnification products. A two-layer molded product using a combination of these 1 and 2 can also be molded.

Next, "molding execution steps" 1, 2, and 3 in FIG. 2 will be explained. 1, the mold consisting of a fixed part and a moving part is tightened, and high-magnification beads are introduced from the A feeder. During this time, feeders B, C, and D will stop. After completion of introduction, heat for a short time or set pressure to 0.2~
Temporary welding is performed using ^{approximately} 0.5Kg/cm2. If the beads are temporarily fused to the extent that they do not collapse, they will be in a state similar to a rubber-like elastic body inside the mold, so they will not bulge or pop out when the mold is opened in step 2.

The mold is opened while pressing the rubber-like elastic body against the movable mold with an eject air, and the gap between the fixed mold and the elastic body is opened so that the distance between the molds becomes constant. In addition,
In order to be able to adjust this interval depending on the purpose, different types of beads or low magnification products are blown into the feeders B, C, and D to fill them when they are stopped at a fixed position set by a limit switch or timer. If the mold is tightened in step 3, the elastic material of the high-magnification product in the mold will be pushed into the mold and will not come out from inside the mold, and will be physically fused with the introduced foreign beads. Become. When the mold clamping is completed, the conventional heating and cooling process is automatically carried out, and a molded product with a color tone pattern obtained by two-layer molding can be taken out.

The synthetic resin foam molded product obtained by two-layer molding as described above has a simple molding process, clearly shows a figure or pattern, has a beautiful appearance, and has practical value as a packaging product. It becomes an expensive molded product.

[Brief explanation of drawings]

FIG. 1 is a perspective view of one example of the present invention, in which two double-layered foam molded products are used in combination. FIG. 2 shows a cross-sectional view of the product, a cross-sectional view of the mold structure, and an explanatory cross-sectional view of the molding process diagram.
1, 2, and 3 of the molding process diagram are explanations of the diagrams (below)
Do it in the following order: 1, 2, 3. A, B, C, D
is the feeder of each location.

Claims (1)

[Claims] 1. Perform initial foam molding by filling pre-expanded beads of synthetic resin such as polystyrene or polyolefin into a single mold consisting of a fixed part and a moving part, and form desired characters and figures on the surface of the molded product. Alternatively, after forming a concave or convex portion having the same shape as the pattern, open the moving part of the single mold to create a gap that fits the concave or convex portion, and then fill the gap with the initial foaming ratio, color, etc. Filled with different beads,
Synthetic resin foam molding for packaging, characterized in that the movable part mold is returned to its original position and two-layer molding is performed by a second foam molding, thereby embodying characters, figures, or patterns on the foam molded product itself. method of manufacturing the product.