JPS599422B2 - Composite container and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite container made of a combination of resin and paperboard, and a method for manufacturing the same.

In general, containers made of a combination of resin (plastic) and paperboard can be filled with liquids, powders, viscous substances, and bulk materials, and in particular, heating filling, which was said to be difficult with conventional paper containers, is also possible due to the material composition. is possible.

However, since the edge of the paper is not exposed on the inner surface of the container, there is no need for special edge treatment to prevent the contents from penetrating, and since the sealing surface is injection molded, the shape is stable and strong. It has the characteristic that a seal can be obtained.

To manufacture such a container, first print a base paper, then laminate the surface, then punch out a blank to match the shape of the container, feed it to an injection mold, and sandwich it between a male die and a female die. The plastic is then injected into a mold cavity consisting of a blank and a metal mold to be molded, and then the mold is opened to take out the product.

To explain this for a cylindrical container as shown in Figures 1, 2, and 3, the blank 1 is a semicircular body piece connected to a circular bottom piece 2 via a connecting part 3, as shown in Figure 2. It consists of 4.

As shown in FIG. 3, the blank 1 described above is formed by printing on a laminated paper 12 made of, for example, paperboard 8, polyethylene 9, At foil 10, and polypropylene 11, coating it with polypropylene, and then punching it out. The punched blank is fitted into a mold and then injection molded to obtain a finished product as shown in FIG.

In FIG. 1, reference numeral 5 indicates the plastic part of the seal between the bottom piece 2 and body piece 4, 6 indicates the plastic part of the seal between the body pieces 4, and 7 indicates the plastic part of the mouth edge. By the way, in a container in which the blank is inserted between the molds and the blanks are integrally molded using injection resin, if the blank is made to have a high barrier structure and the contents are heated and sealed, the container can be stored for a long time at room temperature. It becomes possible.

However, in this case, deformation of the container due to thermal contraction of the contents and air after cooling becomes a problem. The present invention attempts to absorb this heat shrinkage through the special shape of the bottom of the container.

That is, the bottom of the container is bulged outward in advance in a spherical shape, and when it contracts, it dents inward and contracts, thereby preventing the other parts of the container from deforming.

A detailed explanation will be given below based on the embodiments shown in FIGS. 4 to 13.

In the present invention, as described above, the bottom of the container is shaped to bulge outward in advance into a spherical shape. However, if the bottom of the container is made to have a simple bulged shape as shown in FIG. The resin tends to flow to the outside of the container, resulting in poor appearance of the container and poor performance.

That is, in order to obtain a container shaped as shown in FIG. 8, the circular bottom piece 2 of the blank 1 must be warped inward as shown in FIG. 9.

However, in order to form a sealing portion 5 between the bottom piece 2 and the body piece 4, a resin flow path consisting of a ring-shaped and stepped notch 15 is formed around the top of the male mold 13. Moreover, since the end portion 2a of the bottom piece 2 is not in close contact with the female mold 14, the resin flows toward the outside of the bottom piece 2 during injection molding.

Furthermore, if the end 2a of the bottom piece 2 is in close contact with the notch 15, the end 2a of the bottom piece 2 may be exposed from the seal portion 5, which is unfavorable in terms of performance. Therefore, the present invention has been devised so that when the pressure inside the container is reduced due to heat shrinkage, the portion of the bottom that had bulged outwards is recessed inward, and the above-mentioned molding problems do not occur. .

That is, as shown in FIG. 4, the center part of the male mold 13 is spherically bulged outward c, but the peripheral part connected to the notch 15 is provided with an inwardly inclined part d, and the female mold The portions corresponding to 14 and the like were formed in the same shape, and the portion corresponding to the notch 15 of the male die 13 was formed as the flat portion e.

When the mold is formed as described above and the blank 1 is inserted into the female mold 14 using the male mold 13, the end portion 2a of the bottom piece 2 is bent outward and pushed into the inner surface of the female mold 14 by the elasticity of the paper, as shown in FIG. Since the resin is in close contact with the resin flow path 15, the resin will not flow out to the outside of the bottom piece 2, and the end 2a of the bottom part 2 will not protrude from the surface of the notch 15.

Therefore, it is possible to eliminate molding defects caused by bulging the center portion outward.

By using the mold as described above, a molded product as shown in FIG. 6 can be obtained. When the pressure inside the container is reduced, a state as shown in FIG. 7 occurs. The above-mentioned molding is the 10th method regardless of the shape of the container.
As shown in FIG. 11, only the central portion may be bulged into a spherical shape.

Furthermore, when molding is performed as in the present invention, the resin contracts in the circumferential direction at the overlapping part of the resin and paper, that is, the sealing part 5, as shown in FIGS. 12 and 13, so that the spherical shape is further promoted. I will be working in

In this case the radial shrinkage is negligible. In addition, from the outer surface to the inner surface, the blanks are polypropylene, paper, polyethylene, At (aluminum), polypropylene or polyethylene, paper, polyethylene, Atl.
Polyethylene, paper, or laminated paper such as polyethylene is used.

In any case, the present invention provides a container in which blanks are inserted between molds and the blanks are bonded and molded using injection resin, in which the blanks are bulged outward in a spherical shape,
Furthermore, the peripheral part is formed sequentially from the edge toward the center, to the flat part, and then to the part inclined toward the inside of the container, and a method for manufacturing the composite container using a mold having such a shape. When the container shrinks after heating and filling the contents, the spherical bulge formed at the bottom of the container dents inward to prevent the container from deforming as much as possible. It does not flow outward from the resin path and therefore does not impair its appearance.

Furthermore, since the blank end line is not exposed from the seal portion, the performance is not degraded.

[Brief explanation of the drawing]

Figure 1 is a slope view of the composite container. Figure 2 is a developed view of the blank. FIG. 3 is a cross-sectional view of the blank. FIG. 4 is a sectional view of the molded container of the present invention. FIG. 5 is a partial sectional view of the male mold of the present invention. FIG. 6 is a partial sectional view of a container produced using the mold of the present invention. FIG. 7 is a cross-sectional view of the container shown above after being deflated. FIG. 8 is a partial cross-sectional view of one container.
FIG. 9 is a partial cross-sectional view of the male mold for the same container. 10th,
FIG. 11 is a bottom view of a container according to another different embodiment of the present invention. Figures 12 and 13 show a partially cutaway plan view and a partially cutaway side view of the container in its deflated state. 1...Blank, 2...Bottom piece, 4...Body piece, 13.
...Male mold, 14...Female mold, c...
...Bulging part, d...Slanted part, e...
Plane part.

Claims (1)

[Claims] 1. In a container in which blanks are inserted between molds and the blanks are bonded and molded using an injection resin, the bottom part is bulged outward in a spherical shape in a certain range in the center, and furthermore, in the peripheral part. A composite container is formed by sequentially forming a flat part from the edge toward the center, followed by a part inclined toward the inside of the container. 2 A method in which a male mold is used to insert a blank into a female mold, the mold is clamped, and then resin is injected into the clamped mold to join the joints of the blanks with resin. A male mold is used to bulge outward in a spherical shape, and the peripheral part is inclined toward the inside of the container from the edge connected to the ring-shaped notch that becomes the resin flow path. The parts corresponding to the spherical bulge and the inclined part are formed in the same shape, and the part corresponding to the notch of the male mold is formed into a flat part, and resin is injected between the two molds. A method of manufacturing a composite container.