JPH0214897B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a cup-shaped container having a double structure consisting of a relatively rigid outer container and a thin-film flexible inner container. It is something.

[Prior Art] Paper containers with a synthetic resin film on the inner surface have been widely used as inexpensive containers for storing liquid materials. Containers have been manufactured and used in which a bottom wall is formed and the inner surface of the container is entirely made of polyethylene film to withstand the storage of liquid materials. Water-resistant containers have also been manufactured by adhering a polyethylene film to the inner surface of a paper top or polystyrene paper top by vacuum forming.

Furthermore, hot pack paper containers have also been devised in which a part of the synthetic resin film provided inside the body wall is peeled off from the outer paper body wall (for example, Utility Model Publication No. 162.004/1983). ).

[Problem to be solved by the invention] By the way, when the liquid to be filled is a "soft drink", for food hygiene reasons, it not only has to be heated to about 90 degrees Celsius or higher and then filled automatically, but it also has to be filled with bacteria. In order to prevent contamination, the container must be immediately sealed and a so-called hot pack treatment must be applied.

In containers that have been hot-packed in this way, not only does the volume of the filling decrease as the filling is cooled to room temperature, but also gas in the upper space (head space) inside the container, especially gas due to evaporation and liquefaction. A decrease in pressure occurs due to the contraction of the .

If a metal can is used, it will be square, but if a simple container made of paper or the like is used, the side wall of the container will inevitably deform inward due to the reduced pressure inside the container, and a decrease in product value will be avoided. Nakatsuta. Therefore, even if a paper container is made water-resistant by having a synthetic resin film adhered to the entire inside surface of the container, the conventional container cannot be used as a container for hot-packed items. It had its drawbacks.

In addition, as a hot pack container in which the inside of the container is in a reduced pressure state, there is a container in which a part of the synthetic resin film provided on the inner surface of the container body wall peels off from the paper container, reducing the internal volume of the container. Also, in the case of blanks for body walls, which are generally fan-shaped, adhesive is applied only to the necessary parts such as the periphery of the sector, and a blank is formed that has bonded parts and non-bonded parts between the body wall paper and the synthetic resin film. However, since it is difficult to process at high speed, it is difficult to improve the production efficiency of containers.

SUMMARY OF THE INVENTION The present invention aims to eliminate the above-mentioned drawbacks and to provide a method for manufacturing a container that can easily mass-produce hot pack containers comprising a shape-retaining outer container and a deformable inner container.

[Means for Solving the Problems] The present invention involves forming an outer container with air permeability at least at the bottom using a relatively rigid material such as paper base paper or polystyrene paper. Adhesive is applied to the upper surface and the lower part of the inner surface of the body wall, and then the outer container is placed in a mold, and the opening of the outer container is covered with a synthetic resin film, and vacuum molded. The synthetic resin film is stretched along the inside of the outer container by creating a negative pressure in the mold, thereby forming a thin-film flexible inner container made of synthetic resin to be inserted into the outer container. The outer container and the inner container are integrated with the adhesive applied to the outer container.

[Function] The manufacturing method according to the present invention uses a container made of paper or the like, and after applying an adhesive to remove the bottom and lower part of the body wall of the container, an inner container made of synthetic resin is formed by vacuum forming or the like. Since it is molded, it is possible to easily mass-produce a double-walled container, and since the inside of the container is made of synthetic resin, the container can withstand filling with liquid.

Furthermore, in this method, since the adhesive is applied so as to exclude the upper surface of the bottom of the outer container and the lower part of the inner surface of the body wall, the adhesion between the inner container and the outer container is limited to the container mouth and its vicinity. Therefore, since the inner container is made of a thin flexible synthetic resin, the lower part of the body wall and the bottom of the inner container can be separated from the outer container, and the lower part of the body wall and the bottom can be easily deformed. Therefore, it is possible to easily manufacture a double container in which the internal volume of the container can be changed without changing the external shape of the container.

[Embodiment] As shown in FIG. 1, an embodiment of the present invention is made of polystyrene paper, which has a mouth edge 21, a trunk wall 22, and a bottom 23 integrated, and has minute through holes 24 in the bottom 23. A pot-shaped container 11 with adhesive 25 applied from the outside of the mouth rim 21 to the upper part of the body wall 22 is placed in the lower mold 31 of the vacuum forming apparatus 30 as shown in FIG. Insert. After placing the polyethylene film 26 above the container 11 and heating it to a desired temperature, as shown in FIG. Next, negative pressure is applied to the lower mold 31, and the upper side of the bottom of the container is brought into a negative pressure state through the through hole 24 of the bottom 23, and the polyethylene film 26 is spread over the entire inside of the container as shown in FIG. A thin-film flexible inner container 14 is formed, and a polystyrene outer container 13 and a thin-film flexible inner container 1 are formed.
A double structure container 11 consisting of 4 is created.

Therefore, the polyethylene film 26 is attached to the container 11.
As shown in FIG. 3, the film 27 is reliably adhered to the outer container 13 in the areas to which the adhesive 25 is applied, such as the mouth edge 21 and required parts of the body wall 22, and in other areas, that is, the body wall 22. Lower part 29 of the inner surface
The portion of the bottom portion 23 facing the upper surface has a simply attached structure.

When applying a hot pack to the container 11 manufactured in this manner, it is filled with a liquid material heated to about 90° C. and sterilized, leaving a head space, and immediately sealed. The filled liquid then cools and contracts.
In addition, when the steam in the head space liquefies, the inside of the container inevitably becomes a reduced pressure state. The portion 28 attached to the lower portion 29 is easily peeled off from the inner surface of the barrel wall of the outer container and accommodates the reduced pressure due to cooling of its internal volume, as shown in FIG. Therefore, the reduction in gas-liquid volume due to cooling after filling with the high-temperature filling liquid has no effect on the outer container. Therefore, even if a hot pack is applied to the double-walled container produced as described above, there is an advantage that the outer shape is not impaired and the product value is not reduced.

In another embodiment of the present invention, the outer container 13 of the container 12 shown in FIG. After applying the adhesive 25 from the outside of the curled portion 21 to the upper part of the body wall 22, a polyethylene film is stretched in the same manner as in the first embodiment to form a thin film inside the paper outer container 13. A flexible inner container 14 is created. When applying a hot pack to this paper double-structured container 12, since the outer container 13 is made of base paper with high air permeability, the lower part 29 and bottom part 23 of the body wall 22 to which the polyethylene film is not adhered are ,
The outside air permeates between the inner surface of the outer container 13 and the outer surface of the inner container 14, and as shown in FIG. , thereby preventing deformation of the outer container.

[Effects of the Invention] The method for manufacturing a double container according to the present invention includes forming an outer container with air permeability at least at the bottom using a relatively rigid material, and then forming an outer container with air permeability at least at the bottom of the container. Adhesive is applied so as to remove the lower part of the inner surface of the body wall, and then the outer container is covered with a synthetic resin film, and a thin film flexible inner container made of synthetic resin is inserted into the outer container by vacuum forming or the like. This is a method for manufacturing a double-structure container for a hot pack, in which both containers are formed in the outer container and the two containers are integrated with the adhesive applied to the outer container. It is easy to mass-produce a double-walled container with a container, and since the adhesive is applied except for the upper surface of the bottom of the outer container and the lower part of the inner surface of the body wall, the opening of the outer container and the vicinity of the mouth can be easily mass-produced. To provide a simple container for a hot pack, which is formed by an inner container whose bottom and lower part of the body wall are easily deformed, and an outer container which has shape retention, by integrating the inner container and the outer container only by the inner surface of the body wall. It can be easily manufactured.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a double-structure container for hot packs manufactured according to the present invention, and FIGS. 2 and 3 are cross-sectional views showing the procedure for producing the container shown in FIG. FIG. 4 is a cross-sectional view of the case where the container is subjected to a hot pack to reduce the volume of the inner container, and FIG. 5 is a cross-sectional view of a double-structured container for hot packs made of an outer container made of paper with high air permeability. 11=Polystyrene paper container, 12=Paper container, 13=Outer container, 14=Inner container, 21
= mouth edge, 22 = body wall, 23 = bottom, 24 = through hole, 25 = adhesive, 26 = polyethylene film, 27 = adhesive film, 28 = adhered film, 29 = adhesive on inner surface Body wall portion not coated, 30=vacuum forming device, 31=lower mold, 32=
Upper type, 33 = plug assist.

Claims (1)

[Claims] 1. After forming an outer container with air permeability at least at the bottom using a relatively rigid material such as base paper or polystyrene paper, at least the upper side of the bottom and the lower part of the inner side of the body wall of the container are formed. Then, after placing the outer container in a mold, the mouth of the outer container is covered with a synthetic resin film, and negative pressure is created in the mold to remove the synthetic resin. A resin film is stretched along the inside of the outer container to form a thin-film flexible inner container made of synthetic resin to be inserted into the outer container, and the adhesive is applied to the outer container. A method for manufacturing a double-structured container for a hot pack, characterized in that the outer container and the inner container are integrated by bonding the inner container to the outer container at a portion excluding the bottom and the lower part of the body wall.