JP3007321B2 - Packaging bag - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging bag, and more particularly to a packaging bag in which a heat-sealed portion does not tear when opened when an article is put in the bag.

[0002]

2. Description of the Related Art Conventionally, polypropylene (PP) films have been generally used as packaging bags for clothes, foods, etc. because of their excellent transparency and strength.

[0003] When a packaging bag is formed from a resin film, there is a bag in which the bottom is folded and both sides are heat-welded by fusing to form a bag, and the upper end is an opening.

On the other hand, in a handbag made of a cast polypropylene film (hereinafter, referred to as CPP) and a biaxially stretched polypropylene film (hereinafter, referred to as OPP), which is formed into a two-layer film, a finger is provided on an upper portion of the main body of the bag for easy holding. The two-layer film itself is extremely thin, and a separate reinforcing sheet is used to reinforce the handpiece provided on one film because the two-layer film itself is extremely thin. The two pieces that are stuck together are used.

Although there are various methods of laminating the reinforcing sheet, laminating different kinds of materials requires a laminating step in a bag-making process, resulting in a high cost. In order to solve the above-mentioned drawback, a suitable length of the bag body upper part in which the packaging bag is formed in advance is folded inward to form a reinforcing sheet,
There is a configuration in which a hole is provided as a hand-held portion in which a doubled portion is reinforced by sealing its end.

[0006]

However, in the case of a packaging bag in which both sides of the bag are heat-sealed by fusing as described above, when the opening is widened when the articles are put in, it is shown in FIG. As described above, there is a problem that the welded portion C at the end of the opening b of the bag a is torn, and the bag often becomes unusable.

On the other hand, in the case where the opening is folded back to form a four-layer structure, a two-layer film having a CPP having a high sealing strength on the inside and an OPP having a low sealing strength on the outside is used as described above. If it is folded, it will be good in appearance, but if the folded parts are combined at the time of welding to form a bag, the thickness will be four layers in the upper and lower layers in plan view, and since the folded parts are inside each other, the CPP is wrapped in the OPP. As a result, only OPP is welded and the strength is low,
There was a problem that it was easy to tear.

[0008] Further, if the fold is made outward, the CPPs are welded to each other to increase the welding strength. However, the welding by fusing on both sides easily breaks because the folded end (upper end of the bag) of the film becomes round. As in the case of the bag, there is a problem that the side portion is also torn when the opening portion is vigorously opened.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to provide a packaging bag in which a heat-sealed portion does not tear at the time of opening.

[0010] In a bag in which the upper end by the end portions on both sides are folded back a bag bottom made of synthetic resin film has is thermally welded is formed in a bag shape by blowing is opening, opening the opening of the A notch recess is formed in the edge at a position separated from the left and right side end portions by a required distance.

That is, the present invention relates to a bag body formed of a cast polypropylene film and a biaxially stretched polypropylene film, wherein the bottom portion of the two-layer film is folded back and both ends are thermally welded by fusing to form a bag-like body. A handbag provided near the opening of the bag body, and the left and right ends are heat-welded by fusing when forming the bag, and the width portion is sealed to the bag body to form an integral reinforcing portion together with the bag body. Wherein the cast polypropylene film side of the two-layer film constituting the bag body is located inside the bag body, and the reinforcing portion extends from the opening of the bag body. And a notch recess formed at a position at a required distance from each of the left and right side edges at the opening edge of the opening.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 1 is a perspective view of an embodiment of the packaging bag 1 according to the present invention, in which the opening 3 is partially cut away with the opening 3 facing upward. The material is, for example, a two-layer structure in which CPP 20 μ and OPP 30 μ are superposed. It is a film.

The bag 1 is formed of the belt-shaped two-layer film.
The planes are oriented so that they overlap each other inside, so that the OPP plane is outside.

The longitudinal direction is blown at a predetermined interval which is the width of one bag, and the left and right ends are heat-welded to form a seal portion A, and the bent portion becomes the lower bottom portion 2. The upper part is a bag 1 having an opening 3.

At the opening edge of the opening 3 of the bag 1, a substantially semicircular cutout 4 is formed at a position separated from the left and right side ends by a required distance. The required distance in which the notch 4 is provided is preferably substantially equal to the diameter 4a of the notch 4, but can be appropriately selected according to the size of the opening width of the bag 1. It may be provided closer to the center than the distance.

When the bag 1 is to be opened with the force f by providing such a cutout recess 4, the force f is applied to the vertex 5 of the seal portion A if the cutout recess 4 is not present. The seal is peeled from the bottom to the bottom. However, the provision of the notch recesses 4 allows the point of action of the force f to shift from the vertex 5 of the seal portion to the deepest portion of the notch recesses 4, 4. A vertex 5 of A is no longer hung, and the problem of tearing from here is eliminated. FIG. 2 and FIG.
3 shows details of the present invention, and folds both ends of the reinforcing portion 6 extending outward from the opening 3 in FIG. 1 so that the CPP portion is on the outside as shown in an enlarged sectional view in FIG. It is returned and becomes a strong bond by welding between the CCP surfaces during welding.

At this time, when both end faces of the reinforcing portion 6 are blown off from the left and right films where the width of the bag 1 is formed, they are simultaneously bonded by heat welding to form a seal portion B.

The reinforcing portion 6 thus obtained has a bag 1
A horizontally long hole 7 for a handbag is provided through the through hole, so that it can sufficiently withstand practical use as a handbag.

In the case of sealing by welding between the CPP surface and the OPP surface, the pressing force of the heater is increased by making the seal portion C a discontinuous point or a discontinuous line as shown in FIG. Even if it is used as a carrying bag, it will not crack from here.

However, since the uppermost portion 8 of the seal portion B is slightly lower than the vertex 9 like the both ends of the bag 1 shown in FIG. The point coincides with the uppermost portion 8, which increases the risk of tearing.

In order to avoid this, it is desirable to cut the upper part of the bag 1 at the line EE, but if this is done, the number of manufacturing steps will be increased and the cost will be increased.

[0023] It is therefore desirable this that the point of application of force f applied to the bottom of the cutout recess 4 when is a cutout recess 4 of a depth such that the lower side of the top 8.

Next, similar experiments were performed on the above-described experimental examples of the present invention with respect to Comparative Examples 1 and 2 as described below.

COMPARATIVE EXAMPLE 1 Using the same two-layer film as in the embodiment, the upper and lower films of the opening are folded inward, respectively, and a hand-held portion (reinforcing portion).
To form a packaging bag similar to that of the above embodiment. This is because the sealing strength of the reinforcing portion B is weak because the OPPs are heat-welded to each other, and the portion is easily torn at this portion, resulting in that it cannot be practically used as a packaging bag.

Comparative Example 2 A packaging bag similar to that of the embodiment was prepared except that the sealing width of the sealing portion C was a continuous line of 2 mm.

Therefore, for the above embodiment and Comparative Examples 1 and 2, the adhesive strength of each of the seal portions A, B, and C (see FIG. 2 ) was measured at a constant speed using a test piece having a width of 15 mm and a length of 100 mm centered on the seal portion. It was measured with a mold tensile tester. The measurement results are shown in the following table.

[0028]

[Table 1]

[0029]

According to the present invention, the following effects can be obtained by the structure described above.

[0030] 1) CPP can increase the strength of the seal portion of the right and left ends by being returned folded outwardly to. 2) it is possible to improve the sealing strength by the discontinuous seal between reinforcing portion folded and bag body. 3) occurs during opening by providing the cutout recess at the opening edge of the opening portion can be prevented cracking of the Tei was sealed portion.

[Brief description of the drawings]

Shows the FIG. 1 embodiment of the opening of the onset packaging bag according to the light
Some of the perspective view.

[2] the same, plan view showing the overall shape of an embodiment of a packaging bag.

FIG. 3 is an enlarged sectional view of an opening of the packaging bag of FIG. 2;

FIG. 4 is an explanatory view showing a conventional problem.

[Explanation of Signs] 1 bag 2 bottom 3 opening 4 notch recess 4a required distance 6 reinforcing part 7 hole A, B, C each seal part

Claims (1)

(57) [Claims] 1. A bag body formed of a cast polypropylene film and a biaxially stretched polypropylene film, the bottom of which is folded back and both ends are thermally welded by fusing to form a bag. It is provided near the opening, and when forming the bag body, the left and right ends are thermally welded by fusing and the width portion is sealed to the bag body, and the carrying hole drilled together with the bag body in the integrated reinforcing portion is formed. In the two-layer film constituting the bag body, the cast polypropylene film side is located inside the bag body, and the reinforcing portion is such that the cast polypropylene film portion extending from the opening of the bag body is located outside. A packaging bag formed by folding back and forming a cutout recess at a position at a required distance from each of left and right side edges at an opening edge of the opening.