JPS608984Y2 - Mold for foam molding of box-shaped objects - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a mold for molding a box-like object made of foamed resin.

Containers made of foamed resin are used for a variety of purposes because they are lightweight and have excellent insulation properties, but on the other hand, they are extremely brittle, so it is difficult to stack many containers when storing items. When piled up, the side wall tends to break due to the load, which is a drawback.

The present invention was devised in view of the above, and is an object of the present invention to provide a foam molding mold that can easily form a container having a strong side wall.

Hereinafter, embodiments of the present invention will be explained in detail based on the drawings. In FIGS. 1 and 2, 1 is a female mold in the shape of a rectangular box, and 2 is a small male mold in the same shape. Then, the male mold 2 is separably fitted inside the female mold 1, thereby forming a box-shaped molding having a horizontal bottom chamber 3a and a vertical side chamber 3bv3c continuous to the periphery between the two. It forms chamber 3.

Filling ports 4, 4 for filling the raw material into the molding chamber 3 are formed in the bottom surface 1a of the female mold 1. The molding chamber 3 is formed so as to be biased towards the opposite end of the molding chamber 3 so as to be located in the side chamber portions 3b, 3b of the molding chamber 3, respectively.

The filling ports 4, 4 do not necessarily need to be completely opened above the side chambers 3b, 3b, and may be formed in a state that slightly extends over the bottom side portion 3a as shown.

When molding a container using the mold, first, particulate raw material resin (foamed polystyrene) is blown and filled with high-pressure air into the molding chamber 3 through the filling ports 4, 4.

This raw material resin has been pre-foamed in advance, and as a result, each particle has an apparent lower density, but not only does the pre-expansion rate of each particle vary considerably in size, but also the density of each particle itself. Since there are differences in size and weight, the raw material resin contains various particles having different weights and sizes.

Thus, such raw material resin flows into the filling port 4 together with high-pressure air.
, 4, the air is mainly blown into the side chamber 3.
b, 3b and circulates to the adjacent side chambers 3c, 3c, then rises and flows into the bottom chamber 3a, and along with this, the raw material resin is first blown directly into the side chambers 3b, 3b. Each side chamber part 3c, 3c is filled, and then the bottom chamber part 3
filled in a.

At this time, among the particles blown into the side chambers 3b and 3b, particles having a large density and being heavy are hardly swept away by the air flow that ascends the side chambers 3b and 3c and flows into the bottom chamber 3a. 3C, but the particles that have a small density and are lightweight mainly flow into the bottom chamber 3a riding on the air flow. Therefore, the packing density of particles in the side chamber 3bt3c is equal to that of the bottom chamber 3a. It will be higher than that.

When filling the raw material, a crack 5 may be provided between the female mold 1 and the male mold 2 in the side chamber 3 bv 3 c to release air, but in the mold described above, the raw material is directly poured into several chambers. Since the material is blown into the side chambers 3b, 3b, the filling of the raw material into the side chambers can be carried out very smoothly even if no racking is provided, and even if racking is provided, very small cracking is sufficient. Accordingly, it is possible to save the raw materials to be filled.

Next, when the filling of the raw resin is completed, the raw resin is heated and foamed by passing steam through the molding chamber 3 to form a box-shaped container that matches the shape of the molding chamber 3.

The container 6 (FIG. 3) molded in this way is taken out by separating the female mold 1 and the male mold 2.
The density of the side walls 6a, 6b is particularly high, and therefore the strength of the side walls 6a, 6b is much greater than in a container molded by a conventional mold.

Conventionally, this type of foam molding mold is commonly used.
As shown in Fig. 4, the raw material filling port 11°11 is
The raw material is temporarily placed in the molding chamber 12 at an intermediate position on the bottom surface of the molding chamber 12.
After being blown into the bottom chamber 12a of the surrounding side chamber 12b
, 12c, the side chambers 12b, 12c tend to become blind spots during filling due to air flow, and therefore, the side chambers 12b, 12c are filled with a higher density than the bottom chamber 12a. Although it was difficult to fill the raw material, the mold of the present invention described above has an extremely simple structure in which the raw material filling port is simply provided on the side chamber of the molding chamber, so that the raw material can be filled in the side chamber. The packing density can be made higher than that of the bottom chamber, thereby making it possible to easily mold a foamed resin container with a strong side wall.

[Brief explanation of drawings]

FIG. 3 is a perspective view of a container molded by the mold of the present invention, and FIG. 4 is a conventional mold. FIG. 2 is a plan view similar to FIG. 1...Female type, 1a...Bottom surface, 2...
...Male mold, 3...Molding chamber, 3a...
Bottom chamber part, 3a, 3c... Side chamber part, 4...
・Filling port.

Claims (1)

[Scope of utility model registration request] By fitting a small male mold of the same shape into the inside of a box-shaped female mold, a box-shaped molding chamber having a bottom chamber and a side chamber around the bottom chamber is formed between the two; A mold for foam molding a box-shaped object, characterized in that a filling port for filling raw materials into the molding chamber is formed on a side chamber of the molding chamber on the bottom surface of the male mold.