JP6888399B2 - Paper container and its manufacturing method - Google Patents

Description

The present invention relates to a paper container, and more particularly to a polygonal paper container in which one blank is folded along a fold ruled line and a flange portion is formed in an opening, and a method for manufacturing the same.

Since paper containers can be used for contents containing water by providing water-resistant thermoplastic resin layers on the front and back surfaces of paper, paper containers of various shapes have been used for a wide range of purposes in recent years. Has been done.

Above all, as a paper container for storing frozen foods, ice cream, etc., a blank with a water-resistant thermoplastic resin layer on the front and back sides of the paper is folded along the crease line to form a tray or cup. The molded paper container can have a structure in which the end face of the paper is not exposed in the range from the bottom to the top of the container, so even if the contents melt, leakage from the bottom of the container is unlikely to occur. It has characteristics.

On the other hand, in these paper containers, it is necessary to form a flange portion in order to attach the lid, but there is a problem that the contents leak out around the flange portion. One of them is that a small hole is formed at the base of the flange portion at the corner where the side plate and the side plate intersect, which may cause leakage. The second problem is that the lid is incompletely sealed and leakage occurs due to a step in the paper at the overlapping portion of the edge pieces for forming the flange portion.

The tray container blank described in Patent Document 1 is a blank for creating a tray having a rectangular bottom surface for use for the above purposes, and is used at the base of a flange for sealing a lid. This is an attempt to solve the problem that small holes (pinholes) are likely to be formed.

In the tray container blank described in Patent Document 1, it is intended to prevent the occurrence of pinholes by providing small protrusions on the tongue piece extending from the edge piece for forming the flange portion. ..

The flanged paper container described in Patent Document 2 and the blank used for the flanged paper container are intended to prevent pinholes from being generated at the base of the flange portion as in Patent Document 1, and are provided at the corners of the container. This problem is to be solved by forming a substantially octagonal flange portion by providing a corner cut portion bent in a Z shape.

Both the tray container blank described in Patent Document 1 and the flanged paper container described in Patent Document 2 are effective in preventing pinholes that are likely to occur at the base of the flange portion of the paper container. However, it did not provide a solution to the defective lid seal caused by the step of the paper at the flange portion.

Japanese Unexamined Patent Publication No. 2000-255546 Japanese Unexamined Patent Publication No. 2014-5033

The problem to be solved by the present invention is that in a paper container formed by bending one blank into a tray shape or a cup shape and having a flange portion at the opening, there is a step on the flange portion due to overlapping of paper. However, it proposes a paper container in which the contents are less likely to leak and a method for manufacturing the same.

As a means for solving the above problems, in the invention according to claim 1, one blank made of a laminate having a water-resistant thermoplastic resin layer on the front and back surfaces of paper is bent along a crease line. A paper container composed of a molded paper container body and a lid heat-sealed on the flange portion of the paper container body. The flange portion has an overlapping portion of the laminated body, and the flange portion is heat-sealed. A linear recess is formed in the lid and the flange portion across the end face of the laminated body in the overlapping portion, and the depth of the linear recess changes in the length direction. It is a characteristic paper container.

In the paper container according to the present invention, a linear recess that crosses the end face of the laminated body is provided in the overlapping portion of the laminated body existing in the flange portion, so that a lid sealing failure occurs due to a step in the overlapping portion. It became difficult to do.

Further, in the invention according to claim 2 , two or more linear recesses crossing the end face of the laminated body in the overlapping portion are formed in parallel on the lid and the flange portion that are heat-sealed on the flange portion. The paper container according to claim 1 , wherein the paper container is made of the same.

The invention according to claim 3 is a paper container body formed by bending a blank made of a laminate having a water-resistant thermoplastic resin layer on the front and back surfaces of the paper along a crease line, and the paper. In the method for manufacturing a paper container including a lid heat-sealed on the flange portion of the container body, when the lid is heat-sealed on the flange portion of the paper container body, the end face of the laminate in the overlapping portion of the laminate existing in the flange portion. A method of heat-sealing using a seal bar provided with a linear protrusion at a position crossing the paper container, wherein the height of the linear protrusion changes in the length direction. It is a manufacturing method.

The paper container according to the present invention has a paper container body formed by bending a blank made of a laminate having a water-resistant thermoplastic resin layer on the front and back surfaces of the paper along a fold ruled line, and thus contains water. However, even if the contents are stored, it is basically difficult for the contents to leak from the bottom and side surfaces.

Further, in the overlapping portion of the laminated body inevitably generated in the flange portion, the linear recess provided so as to cross the end face of the laminated body causes a defective lid seal due to a step in the flange portion caused by the end face of the laminated body. Since it exerts a preventive effect, it is less likely that a defective lid seal will occur.

When the linear recess has a depth that changes in the length direction as in the invention of claim 2, by arranging the recess in accordance with the step position of the laminated body, the recess is arranged. The leakage prevention effect can be maximized while minimizing damage to the flange and lid.

As in the invention of claim 3, two or more linear recesses crossing the end face of the laminated body in the overlapping portion are formed in parallel on the lid and the flange portion that are heat-sealed on the flange portion. In the case, the effect of preventing leakage due to poor sealing at the stepped portion is more reliable than in the case of one.

In addition, in the arrangement of two or more linear recesses, by bringing one inside closer to the base portion of the flange portion inside the flange portion, it is possible to exert an effect on pinhole countermeasures at the base portion of the flange portion. It becomes.

According to the method for manufacturing a paper container according to claim 4, when the contents are stored in the paper container body and the lid is heat-sealed, only a linear convex portion is provided at a predetermined position of the seal bar. With the simple equipment of, it is possible to manufacture a paper container without a defective lid seal.

FIG. 1 is a perspective explanatory view showing an embodiment of a paper container according to the present invention. FIG. 2 is a perspective explanatory view showing a state in which the lid of the paper container shown in FIG. 1 is removed. FIG. 3 is a schematic plan view showing a blank of the paper container main body of the paper container shown in FIG. FIG. 4 is a partially enlarged view of an overlapping portion of the laminated body in the flange portion of one embodiment of the paper container according to the present invention. FIG. 5 is a partially enlarged schematic view of an overlapping portion of the laminated body in the flange portion of another embodiment of the paper container according to the present invention. FIG. 6 is a schematic plan view showing an embodiment of a seal bar used in the method for manufacturing a paper container according to the present invention. 7 (a) is an enlarged view of part A of FIG. 6, FIG. 7 (b) shows a schematic side view, and FIG. 7 (c) shows a schematic elevation view. FIG. 8 is a schematic plan view showing another embodiment of the seal bar used in the method for manufacturing a paper container according to the present invention. 9 (a) is an enlarged view of a portion B of FIG. 8, FIG. 9 (b) shows a schematic side view, and FIG. 9 (c) shows a schematic elevation view.

Hereinafter, the paper container according to the present invention and the manufacturing method thereof will be described in detail with reference to the drawings. FIG. 1 is a perspective explanatory view showing an embodiment of the paper container 1 according to the present invention, and FIG. 2 is a perspective explanatory view showing a state in which the lid 3 of the paper container 1 shown in FIG. 1 is removed. is there. Further, FIG. 3 is a schematic plan view showing a blank 10 of the paper container main body 2 of the paper container 1 shown in FIG.

The paper container 1 according to the present invention includes a paper container main body 2 formed by bending a blank 10 made of a laminate having a water-resistant thermoplastic resin layer on the front and back surfaces of the paper along a crease line, and a paper container. It is a paper container including a lid 3 that is heat-sealed on the flange portion 4 of the main body 2. The flange portion 4 has an overlapping portion 5 of the laminated body, and the lid 3 and the flange portion 4 that are heat-sealed on the flange portion 4 are formed with a linear recess 7 that crosses the end surface 6 of the laminated body in the overlapping portion 5. It is a paper container characterized by being made.

Since the paper container 1 according to the present invention has a paper container main body 2 formed by bending a blank 10 made of a laminate having a water-resistant thermoplastic resin layer on the front and back surfaces of the paper along a fold ruled line.
There is no exposed end face of the paper below the flange portion 4. Therefore, even when the contents containing water are stored, the contents do not leak from the paper container body.

FIG. 3 is a schematic plan view showing a blank 10 of the paper container main body of the paper container shown in FIG. FIG. 3 is a view of the laminated body constituting the blank from the surface side (the side that becomes the outside of the container), and the dotted line in the figure shows the mountain fold ruled line and the alternate long and short dash line shows the valley fold ruled line.

In the blank 10, two side plates 12 and two second side plates 13 are connected to each other with a bottom plate 11 as a center via a mountain fold ruled line. Between the side plate 12 and the second side plate 13, an inverted triangular folded joint plate 18 and a second folded joint plate 19 are connected in series to form a blank having one connection as a whole.

The four corner portions of the paper container are overlapped so as to cover the folding joint plate 18 on the outside of the second folding joint plate 19, and the whole is adhered to the outside of the second side surface plate 13. This forms the lower part of the container body.
The flange portion 4 is formed by connecting the edge piece 14, the second edge piece 15, and the joint edge piece 20 extending from the side plate 12, the second side plate 13, and the folding joint plate 18, respectively. As for the vertical relationship, the joint edge piece 20 is folded under the second edge piece 15, and the second tongue piece 17 of the second edge piece 15 is adhered on the tongue piece 16 of the edge piece 14.

As a result, the end face 6 of the laminated body, which is the end face of the second tongue piece 17, is exposed at the four corners. Since this step corresponds to the thickness of the laminated body, normally, when the lid 3 is heat-sealed to the container body 2, even if a considerable pressure is applied with a seal bar to seal the lid 3, a gap is rarely created. In some cases, it remained.

In the paper container 1 according to the present invention, a linear recess 7 is formed in the overlapping portion 5 of the laminated body existing in the flange portion 4 so as to cross the end surface 6 of the laminated body, whereby this gap is formed. Was able to be suppressed almost completely.

FIG. 4 is a partially enlarged view of the overlapping portion 5 of the laminated body in the flange portion 4 of the embodiment of the paper container 1 according to the present invention. FIG. 4 shows a state in which the lid 3 is removed for easy understanding. The flange portion 4 has an overlapping portion 5 of the laminated body, and the lid and the flange portion that are heat-sealed on the flange portion are formed with a linear recess 7 that crosses the end surface 6 of the laminated body in the overlapping portion 5. There is.

In the example of this figure, the second tongue piece 17 extending to the second edge piece 15 overlaps the tongue piece 16 extending to the edge piece 14, and the end face 6 is exposed. The linear recess 7 is provided so as to cross the end surface 6 of the laminated body.

Even if a gap is created along the step based on the end surface 6 of the laminated body when the lid is sealed, the presence of the linear recess 7 blocks the gap and prevents the gap from reaching the outside of the paper container.

The size of the linear recess 7 is preferably about 0.5 mm to 1.5 mm in width, about 5 mm to 10 mm in length, and about 0.2 mm to 1 mm in depth, and the shape may be linear or curved. ..

As a method of forming the linear recess 7, as shown in FIG. 6, linear protrusions 31 are provided at four corners of the seal bar 30 for heat-sealing the lid 3, and the same as usual. The method of heat sealing is the simplest and most efficient.

FIG. 7 is an explanatory view of the linear protrusion 31. 7 (a) is an enlarged view of part A of FIG. 6, FIG. 7 (b) shows a schematic side view, and FIG. 7 (c) shows a schematic elevation view. In this example, the linear protrusion 31 has a trapezoidal cross section and a flat upper surface. The dimensions of the linear protrusion 31 are, for example, about 1.5 mm in width, 9 mm in length, and 1 mm in height.

FIG. 8 is a schematic plan view showing another embodiment of the seal bar 30 used in the method for manufacturing a paper container according to the present invention. 9 (a) is an enlarged view of a portion B of FIG. 8, FIG. 9 (b) shows a schematic side view, and FIG. 9 (c) shows a schematic elevation view. In this example, the linear protrusion 31 is characterized in that the height changes in the length direction to form a taper.

When the lid is sealed using such a seal bar, it is possible to form a paper container having a linear recess whose depth changes in the length direction. By doing so, since the concave portion can be formed along the step of the laminated body without difficulty, the seal of the portion without the step is not adversely affected, and more stable sealing is possible. It also has the effect of shortening the sealing time.

As for the taper of the linear protrusion 31, a normal laminated body having a thickness of about 400 μm and about 10: 1 is appropriate. Good results can be obtained by changing the paper thickness to about 2: 1 when the paper thickness is thicker than this and about 15: 1 when the paper thickness is thinner.

FIG. 5 is a partially enlarged schematic view of the overlapping portion 5 of the laminated body in the flange portion 4 of another embodiment of the paper container 1 according to the present invention. In this example, the lid 3 and the flange portion 4 that are heat-sealed to the flange portion 4 are formed with two linear recesses 7 that cross the end surface 6 of the laminated body in the overlapping portion 5 in parallel. It is a feature.

As described above, the presence of two or more linear recesses 7 makes the effect of blocking the gap generated in the stepped portion due to the end surface 6 of the laminated body more perfect. Further, although not shown in particular, by providing the inner one of the plurality of pieces near the base of the flange portion, the effect of crushing the pinholes that tend to occur at the base of the flange portion can be expected.

The paper used for the paper container according to the present invention includes ^{paperboard of about 400 to 850 g / m 2 of} Manila cardboard, white ball, and chip ball, double-sided card paper, back white cardboard, ivory paper, and basis weight 160 to 600 g /. A carton base paper, a cup base paper, etc. of about m ^{2 can be used.}

As the water-resistant thermoplastic resin layer provided on both sides of the paper, polyolefins such as low-density polyethylene resin (LDPE), high-density polyethylene resin (HDPE), linear low-density polyethylene resin (LLDPE), and polypropylene resin (PP) are provided. A based resin, a polyester resin such as unstretched polyethylene terephthalate resin (PET), a polyamide resin such as unstretched nylon, and the like can be used.

1 ... Paper container 2 ... Paper container body 3 ... Lid 4 ... Flange part 5 ... Overlapping part 6 ... End face 7 of laminated body ... Linear recess 10 ... Blank 11 ... Bottom plate 12 ... Side plate 13 ... Second side plate 14 ... Edge piece 15 ... Second edge piece 16 ... Tongue piece 17 ... Second tongue piece 18 ... Folded joint plate 19 ... Second folded joint plate 20 ... Joint edge piece 30 ... Seal bar 31 ... Linear protrusion

Claims (3)

A paper container body formed by bending a blank made of a laminate having a water-resistant thermoplastic resin layer on the front and back surfaces of the paper along a crease line, and a lid heat-sealed on the flange portion of the paper container body. In a paper container made of, the flange portion has an overlapping portion of the laminated body, and the lid heat-sealed on the flange portion and the flange portion cross the end face of the laminated body in the overlapping portion. A paper container in which a linear recess is formed, and the depth of the linear recess changes in the length direction. Claim 1 is characterized in that two or more linear recesses that cross the end faces of the laminated body in the overlapping portion are formed in parallel on the lid that is heat-sealed on the flange portion and the flange portion. The paper container described in. A paper container body formed by bending a blank made of a laminate having a water-resistant thermoplastic resin layer on the front and back surfaces of the paper along a crease line, and a lid heat-sealed on the flange portion of the paper container body. In the method for manufacturing a paper container composed of the above, when the lid is heat-sealed on the flange portion of the paper container body, a linear protrusion is provided at a position crossing the end face of the laminate in the overlapping portion of the laminate existing in the flange portion. A method for manufacturing a paper container, which is a method of heat-sealing using a seal bar, wherein the linear protrusions change in height in the length direction.

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