JPS6366745B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing liquid leakage from the top of a liquid storage paper box (hereinafter sometimes simply referred to as a paper box).

Traditionally, liquid storage paper boxes made of paperboard coated with thermoplastic synthetic resin or laminated with thermoplastic films on both sides have been used as containers for milk, juice, etc., and recently they have been used as containers for alcoholic beverages (e.g. Japanese sake). It is also used as a container.
However, some of these paper boxes are not completely heat-sealed, and as shown in the end surface of FIG.
The liquid that leaks out may leak out through the gap 7 shown in Figure 3C, especially if the liquid is alcoholic beverages, it does not contain glue-like substances such as casein contained in milk and the surface tension is low. Since it is small, it has the disadvantage that it tends to leak if a gap 6 is created.

The present inventors conducted research to solve the above-mentioned drawbacks, and as a result, as shown in the developed view of FIG. The upper ends of the upper pieces 2 and 4 have symmetrical heights with the center as the border, and when the paper box is assembled, the outer upper pieces 1 and 3 are folded together as shown in the cross-sectional view in Figure 3C. Since the upper ends of the inserted inner upper piece 4 are lined up at the same height, even if heat sealing is applied, the upper ends of the inner upper piece 4, the outer upper piece 3, and the glue margin piece 5
It was discovered that if a gap 7 exists between the inner surface of the glue strip 5 and a gap 6 is generated at the free end of the adhesive strip 5, liquid will leak through the path shown by the arrow in Figure 3A. However, if the upper ends of the inner upper pieces 4 and 5, which are folded inside the outer upper pieces 1 and 3 and are directly heat-sealed, are not lined up, the gap 7
They completed the present invention by discovering that it is possible to make the size very small or even eliminate it.

That is, the present invention has two outer upper pieces that are arranged in a row alternately in the horizontal direction via fold lines, and that form the outermost surface of the top when the paper box is completed, and two outer upper pieces that are folded inside the outer upper pieces and heated. Two inner upper pieces to be sealed, and an inner upper piece that is connected to one side edge of the four connected upper pieces through a fold line and heat-sealed along the other side edge. The upper end of the paper material for a liquid storage paper box is heat-sealed to form a liquid storage paper box, which has a thermoplastic synthetic resin layer on both the front and back sides, and a glue margin piece that is folded between the outer upper pieces and heat-sealed. When forming the top, the number of sheets of paper constituting the heat-sealed portion of the top of the liquid storage paper box is determined by heat-sealing the width of 1 mm in the area where the glue strip exists and adjacent to the free end of the glue strip.
The central part of the paper box that can be formed above is reduced one by one from the bottom to the top along the height direction until there are only two outer upper pieces, and the heat seal width of each number of pieces is at least 1 mm or more. The present invention provides a method for preventing liquid leakage from the top of a liquid storage paper box, which is characterized in that liquid leakage from the top is prevented by using the following method.

Hereinafter, the method for preventing liquid leakage at the top of a liquid storage paper box according to the present invention will be further explained based on the drawings. FIG. 4 is a developed view of an embodiment of the upper part of a liquid storage paper box that implements the liquid storage paper box top part leak prevention method according to the present invention, and FIG. 5A is a completed liquid storage paper box in FIG. 4. FIG. 5B is an enlarged front view of the upper part of the screen, and FIG.
Fig. 7 is a developed view corresponding to Fig. 4 of another embodiment of the upper part of a liquid storage paper box for carrying out the method for preventing liquid leakage at the top of the liquid storage paper box according to the present invention, and Fig. 8 is a developed view corresponding to Fig. 4. FIG. 8 is an end view of the body of the liquid storage paper box in FIG. 7 when completed; In the drawing, 1 and 3 are outer upper pieces that form the outermost surface of the top when the paper box is completed, and 2 and 4 are laterally connected alternately to the outer upper pieces 1 and 3 through fold lines, and when the paper box is assembled. The inner upper piece is folded and heat-sealed between the outer upper pieces 1 and 3, and 5 is the four upper pieces 1, 2, which are connected laterally through the fold line.
The four upper pieces 3 and 4 are connected to each other via a fold line on one side edge, and are heat-sealed along the other side edge of the four upper pieces that are connected in a horizontal direction. It is a glue margin piece that is folded and heat-sealed between pieces 1 and 3, and there are four upper pieces 1,
2, 3, 4 and the upper end of the adhesive strip 5, as shown in FIG. Then, adjacent to the free end of the glue allowance piece 5, the width of the heat-sealed paper box can be formed by 1 mm or more, and the width is reduced one by one from the bottom to the top along the height direction until only the outer upper pieces 1 and 3 remain. It is sufficient that the heat-sealing width is at least 1 mm or more for each number of sheets, as illustrated in FIGS. 4, 6, and 7. Here, heat seal width is 1mm.
The above limitation is due to the fact that if the heat seal width is less than 1 mm, the heat seal area of each directly heat sealed surface will be too small and the heat seal strength will be weak and there is a possibility that the heat seal part will peel off. This is due to the fact that the heat sealing performance may not be exhibited due to the large amount of heat sealing, and the possibility that the difference in level between the paper materials becomes large, resulting in a gap.

Furthermore, as shown in FIGS. 6 and 7, the inner upper pieces 3 that are not folded together with the glue allowance pieces 5 are also folded outward one by one from the bottom to the top along the height direction within a certain range from the edge of the paper box. It is preferable to reduce the heat sealing width until only upper pieces 1 and 3 are left, and to have a heat seal width of at least 1 mm for each number of pieces, and also to avoid the presence of a liquid with low surface tension and strong penetrating power, and a thermoplastic synthetic resin. In order to avoid contact with the edges of the blank paper material, the free end of the glue strip 5 is covered with a tape 9 coated with thermoplastic synthetic resin as shown in FIG. 5
It is more preferable to have a structure in which a part of the paper box can be folded back, and to heat-seal the box by folding it back as shown in FIG. 8, since the liquid will soak into the paper material, weakening the paper box and preventing the liquid from leaking.

In the present invention, only an embodiment having a gable top-shaped top as shown in FIG. This method can also be applied to paper boxes for storing liquids.

If the method for preventing liquid leakage at the top of a liquid storage paper box according to the present invention as described above is carried out, the upper end of the inner upper piece folded inside the outer upper piece and the upper end of the glue margin piece can be aligned at the same height. The large gap 7 that existed in the past as shown in Figure 3C becomes very small or even completely closed and disappears, as shown by 8 in Figure 5B. It is a liquid with a small surface tension such as
Even if a gap 6 occurs at the free end of the paper, the liquid content will not leak out, and the size of the paper material used is almost the same as that of conventional paper, so its industrial value is great. It's a big one.

[Brief explanation of drawings]

Figure 1 is a perspective view of the top of a gable-top liquid storage paper box, Figure 2 is a developed view of the upper part of a conventional liquid storage paper box, and Figure 3A is the completed liquid storage paper box in Figure 2. An enlarged front view of the upper part, FIG. 3B is an end view taken along the Y-Y line in FIG. 3A, FIG. 3C is a sectional view taken along the Z-Z line in FIG. 3A, and FIG. 4 is a liquid storage according to the present invention. FIG. 5A is an enlarged front view of the upper part of the liquid storage paper box when the liquid storage paper box is completed in FIG. 4; Figure B is Figure 5A
The cross-sectional view taken along the line X-X in FIG. 6, and FIG. 7 respectively correspond to FIG. A developed view corresponding to example Fig. 4,
FIG. 8 is an end view of the body of the liquid storage paper box in FIG. 7 when completed. 1, 3...Outer top piece, 2, 4...Inner top piece, 5...Upper glue piece, 6, 7, 8...Gap, 9
……tape.

Claims (1)

[Claims] 1. Two outer upper pieces that are alternately connected in the horizontal direction via fold lines and form the outermost surface of the top when the paper box is completed, and an inner side that is folded inside the outer upper pieces and heat-sealed. The two upper pieces are connected to one side of the four connected upper pieces through a fold line, and are heat-sealed along the other side edge to form an inner upper piece and an outer upper piece. The liquid storage paper box paper material has a thermoplastic synthetic resin layer on both the front and back sides, and is made of a glue margin that is folded in between and heat sealed.The upper end of the paper material is heat-sealed to form the top of the liquid storage paper box. In this case, the number of sheets of paper constituting the heat-sealed part at the top of the paper box for liquid storage is determined by determining the number of sheets of paper that constitutes the heat-sealing part at the top of the paper box for liquid storage in the area where the adhesive strip exists and the center side of the paper box where a heat-seal width of 1 mm or more can be formed adjacent to the free end of the adhesive strip. The liquid from the top is reduced one by one from the bottom to the top along the height direction until there are only two outer upper pieces left, and the heat seal width of each piece is at least 1 mm. A method for preventing liquid leakage at the top of a liquid storage paper box, characterized by preventing leakage.