JPS628301B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a packaging box made of a thermoplastic soft synthetic resin sheet.

Generally, boxes made of soft synthetic resin sheets are used to package hairbrushes, electric razors, toothbrushes, etc., but conventionally, in order to manufacture packaging boxes made of soft synthetic resin sheets, The left and right side plates and the bottom plate that make up the sides and bottom of the box body are integrally connected to the front plate that makes up the surface of the body, and these both side plates and the bottom plate are connected to the front plate that makes up the front surface of the box body, and these side plates and the bottom plate are connected to the front plate that makes up the front surface of the box body. Heat sealing is performed against the

However, with this method, the heat seal line protrudes around the completed packaging box, resulting in an unsightly appearance, and the heat seal line is hard and sharp, making it difficult to touch. It's bad.

Therefore, the box manufactured as described above,
It may be possible to turn the box upside down so that the heat-sealed line is located inside the box, but since there is a risk of the box being torn at the heat-sealed line, it requires a considerable amount of effort to turn the box over. This significantly increases manufacturing costs, and furthermore, when the box is turned over, there are no corners at the heat-sealed lines, further deteriorating the appearance.

The present invention provides a method to solve this problem.

In order to achieve this object, the present invention provides a packaging box made of a thermoplastic soft synthetic resin sheet, which includes a top sheet forming the front surface of the box, and a back sheet forming the back surface of the box. An intermediate product is obtained by overlapping the two sheets and heat-sealing them together at the three side edges, which are the left and right sides and the bottom of the box.Then, this intermediate product is molded into a core mold. The heat-sealing line in the intermediate product is fitted onto the core mold so that the heat-sealing wire is positioned on the side surface of the core mold, and the heat-sealing wire in the intermediate product is inserted into the core mold by a heating outer mold facing the side surface of the core mold. It is constructed so that it is sandwiched between the two and heated and press-molded.

Embodiments of the present invention will be described below with reference to the drawings. 1 is a packaging box made of soft vinyl chloride, the front plate 2 and the back plate 2 are formed to have a width h ₁ , and both the front and back plates 2, 2 are By bending the left and right side parts 3, 3 and the bottom part 4 at approximately right angles, the side parts 3, 3 with a width _h2 , and the width
The bottom part 4 of h ₃ is integrally formed, 5, 5 is the inner lid with width h ₂ and length l ₁ , and 6, 6 are the above-mentioned top plate 2 back plate 2.
A hanging part that also serves as an outer lid is integrally extended from the upper end of the lid, and both hanging parts 6, 6 can be opened and closed by a pair of fasteners 7 such as hooks.

Next, the method of manufacturing this box 1 will be described step by step. 2', 2' are front and back sheets made of soft vinyl chloride, and these two sheets 2' are placed between the two sheets 2', 2'.
2' is a release sheet 8 made of polypropylene, polyethylene, etc., which is not thermally welded, and is shifted to one side and sandwiched between the two sheets 2' and 2'. This is thermally cut by upper and lower dies (not shown) and punched into an intermediate product 1' of the box 1. The intermediate product 1' has a symmetrical shape on the front and back, and both the front and back sheets 2', 2' are heat-sealed 14 at the time of thermal cutting along the U-shape of the symbol (ABOCD), and the front and back sheets are sealed 14 at the part where the release sheet 8 is inserted. Both sheets 2', 2' are not welded together. Further, the area surrounded by the symbol (ABOCD) in the intermediate product 1' is approximately half the width (h ₂ /2) of the left and right side surfaces 3, 3 on the left and right sides of the top plate 2 or back plate 2 of the box 1, and the top plate. Or, it has a planar shape with approximately half the width (h ₃ /2) of the bottom part 4 developed at the lower end of the back plate, and the tongue pieces 5', 5', 5',
5' is formed to have a width h ₄ slightly wider than approximately half the width of the inner lid 5 in the box body 1, and the tongue pieces 6', 6' correspond to the hanging parts 6, 6 which also serve as the outer lid in the box body 1. 9 and 9' shown by two-dot chain lines are fold lines along which the sheet can be bent.

Next, by peeling off both tongue pieces 6', 6' for the hanging parts 6, 6 on the front and back sides of the intermediate product 1' and peeling off the release sheet 8 from between them, the opening 10 in the box body 1 is formed.
It is possible to open the area where .

Then, the intermediate product 1' is placed in a tip core mold 12 whose tip is semicircular and whose circumferential surface 11 has a thickness _h3 , with its heat-sealed wire 14 positioned on the circumferential surface 11 of the tip core mold 12. It is fitted in this way (see Figure 5). The tip core mold 12 is pressed against the tip outer mold 13 having a semicircular concave peripheral surface 15 corresponding to the semicircular portion of the tip core mold 12, and the tip outer mold 13 is heated to below the softening point of the vinyl chloride resin. Then, the heat seal line 14 in the region (BOC) sandwiched between the tip core mold 12 and the tip outer mold 13 is crushed and formed into a flat shape, and the width of the tip core mold 12 is _h3
A U-shaped bottom part 4 corresponding to the seventh part can be formed.
(see figure).

After the tip core mold 12 is extracted from the intermediate product 1', a circumferential surface 17,1 having a width _h2 corresponding to each inner width of the left and right side surfaces 3,3 of the box body 1 is replaced.
7 is inserted through the opening of the intermediate product 1', and the areas (AB) and Heat seal wire 14,1 shown as (CD)
4, and heated upper and lower outer molds 1.
The side core mold 16 is placed between the upper and lower circumferential surfaces 17, 18 facing each other, and the side core mold 16 is held together with the intermediate product 1' by the upper and lower outer molds 18, 18. By pressing and clamping, the heat-sealing lines 14, 14 are crushed and become flat, and the side portions 3, 3 of the box body 1 having a width _h2 are formed between the heat-sealing lines 14, 14. (See Figure 11). At this time, the left and right tongue pieces 5' for the inner lid 5,
5', 5', 5' overlap each other slightly in dimension e (see Fig. 12), so the upper and lower outer molds 18, 1
8 and the side core mold 16, the inner lids 5, 5 can be formed by welding in that state.

In addition, as the release sheet 8, for example, a nylon sheet or a cellophane sheet, which cannot be thermally cut at the same time when the front and back sheets 2' and 2' are thermally cut, may be used. Since only the intermediate product can be pulled out, the work of turning over the tongue pieces 6', 6', etc. can be omitted. In addition, it is also possible to simultaneously press the outer mold at the tip and the upper and lower sides of the outer mold on the three circumferential surfaces of the core mold, and at this time, if the core mold is made into a split mold so that it can be expanded and contracted,
The core mold is easy to take out, and the shape of the side surface of the box body 1 can be made arbitrarily.

In summary, according to the present invention, the front and back sheets made of soft thermoplastic synthetic resin are overlapped, and the three side edges of the sheets corresponding to the left and right sides and the bottom of the finished box are heat-sealed at the same time. The above-mentioned sheets were heat-sealed and punched to become an intermediate product of the box body, and this intermediate product was fitted into a core mold so that the heat seal line in this intermediate product was located on the peripheral surface of the core mold. When the outer mold and the core mold are sandwiched together and heated, the heat-sealed line is crushed flat, and at the same time, the heat-sealed line is sandwiched and the appropriate width is formed on the side and bottom parts of the box. The heat-sealing line does not protrude outward from the box, and the box looks good, and the sides of the box are smooth and feel good to the touch. In addition, it is possible to eliminate the hassle of turning the intermediate product inside out after heat sealing as in the past, so there is no risk of breaking the heat seal line during manufacturing, reducing manufacturing costs. Appropriate patterns can also be applied to the sides of the box by heating and pressing.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a perspective view of a completed box, Fig. 2 is a sectional view of the box in a closed state indicated by the line - in Fig. 1, and Fig. 3 is a manufacturing method. Fig. 4 is a sectional view taken along the line - - in Fig. 3, Fig. 5 is a sectional view showing the second step of the manufacturing method, and Fig. 6 is a state in which the bottom of the box is molded. 7 is a cross-sectional view taken along the line - in FIG. 6, FIG. 8 is a cross-sectional view showing the third step of the manufacturing method, FIG. 9 is a cross-sectional view taken along the line - in FIG. 8, and FIG. 8 is a cross-sectional view taken along the line XII of FIG.
It is a sectional view taken along the line XII. 1...Packaging box body, 2', 2'...Front and back sheets, 1'
...Intermediate product, 14...Heat sealing wire, 8...Release sheet, 12...Tip core mold, 11...Surrounding surface, 13...Tip outer mold, 16...Side core mold, 17, 17...Surrounding surface, 1
8, 18...lateral external mold.

Claims (1)

[Claims] 1. In a packaging box made of a thermoplastic soft synthetic resin sheet, a top sheet forming the front surface of the box and a back sheet forming the back surface of the box are overlapped, and both sheets are combined with the An intermediate product is obtained by heat-sealing the left and right sides and three side edges of the bottom of the box, and then the heat-sealed line of the intermediate product is applied to the core mold. is fitted so as to be positioned on the side surface of the core mold, and the heat-sealing wire in the intermediate product is sandwiched between the core mold and the heated outer diameter facing the side surface of the core mold, and heated and press-molded. A method for manufacturing a packaging box, characterized by: