JP3044487U - Packaging bag - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] An object is to provide a packaging bag in which the sealing strength does not decrease. SOLUTION: A bag main body 1 in which a bottom portion and left and right ends of a two-layer film composed of a cast polypropylene film and a biaxially oriented polypropylene film are formed in a bag shape by fusing, and a bag main body 1 is provided in the vicinity of an opening 3 thereof and left and right by fusing. In a packaging bag having a horizontally elongated hole 5 in a reinforcing portion 4 whose end is heat-welded and whose width portion is integrated with the bag body 1 by a seal 6, cast polypropylene among the two-layer films constituting the bag body 1. The film sides are arranged inside the bag, and the reinforcing portion 4 is formed by forming the cast polypropylene film portion outside in the opening 3 of the bag body 1.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a packaging bag, and more particularly to a packaging bag suitable for carrying by hand.

[0002]

[Prior art]

 Conventionally, polypropylene (PP) film has been widely used as a packaging bag for clothes, foods, etc. because of its excellent transparency and strength.

However, in a handbag bag made by laminating a cast polypropylene film (hereinafter, referred to as CPP) and a biaxially stretched polypropylene film (hereinafter, referred to as OPP) into a two-layer film, a finger is placed on the upper portion of the bag body so that it can be easily held. A handheld part is provided with a horizontal hole that is large enough to accommodate a single hand. The handbag part is a separate layer to strengthen the handbag part provided in one film because the 2-layer film itself is extremely thin. A reinforced sheet is used to make two sheets.

There are various methods for bonding the reinforcing sheet, but if different materials are bonded together, a bonding step is required before bag making, which is disadvantageous in that the cost is high.

[0005]

[Problems to be solved by the device]

 Therefore, in the case of a film with good heat-sealing property, in order to eliminate the above-mentioned drawbacks, a suitable length of the upper part of the bag body where the packaging bag is formed is folded back inward to form a reinforcing sheet, and its end is sealed. In some cases, a hole is provided as a handbag part by strengthening the doubled part.

[0006] However, in the case of a two-layer film of CPP and OPP, it may be good to fold it inward as described above, but if the folds are joined together when welding to form a bag, it will be seen in a plan view. However, since the thickness of the upper and lower layers is four and the folded portions are inside each other, the CPP is wrapped in the OPP, and as a result, only the OPP is welded, resulting in low strength and easy tearing.

[0007]

[Means for Solving the Problems]

 An object of the present invention is to provide a packaging bag whose seal strength does not decrease in order to solve the above problems.

That is, the invention according to claim 1 is a bag main body formed into a bag shape by folding back the bottom part of a two-layer film made of a cast polypropylene film and a biaxially stretched polypropylene film and heat-sealing the left and right ends by fusing. And a reinforcing portion which is provided in the vicinity of the opening of the bag main body, the left and right ends are heat-welded by fusing when the bag main body is formed, and the width portion is sealed by the bag main body. In the packaging bag having a hole for carrying a bag formed together with the bag body, the two layers of the film constituting the bag body are made so that the cast polypropylene film sides are inside each other, and The portion is formed by folding back the cast polypropylene film portion at the opening of the bag body.

According to a second aspect of the present invention, in the device according to the first aspect, the bottom portion of the bag body is a square bottom, and in the third aspect, the bag body and the reinforcing portion are provided. It is characterized in that the longitudinal seal is a discontinuous point or a discontinuous line.

[0010]

[Embodiment of the invention]

 Hereinafter, the present invention will be described with reference to embodiments shown in the drawings. FIG. 1 shows a front view of the packaging bag according to the present invention with the opening 3 facing forward. The material is a two-layer film in which CPP 30 μ and OPP 20 μ are superposed.

The bag body 1 is formed of the strip-shaped two-layer film, and when the upper and lower sides in the longitudinal direction of the bag body 1 are folded in two, the CPP surfaces are oriented so as to overlap each other inside. Therefore, the OPP surface is on the outside thereof.

Then, the longitudinal direction is melted and cut at a predetermined interval which is the width of one bag, and the left and right side end portions thereof are heat-welded, so that the folded portion becomes the lower bottom portion 2 and the upper portion has the opening portion 3. The bag body 1 is obtained.

The reinforcing portion 4 extending outward from the opening 3 in FIG. 1 is folded back so that the CPP 30 μ portion is on the outside as shown in the enlarged XX section of the detail in FIG. At that time, the CPP surfaces directly contact each other at their side edges, so that the adhesion becomes strong, but when they are folded back inward, the contact is welded between the OPP surfaces, so that strong adhesion cannot be obtained.

At this time, both ends of the reinforcing portion 4 are simultaneously adhered by heat welding when the left and right end films where the width of the bag body 1 is formed are melted.

The reinforcing portion 4 thus obtained is provided with the bag body 1 and the laterally long hole 5 for carrying, which is sufficiently practical for carrying.

Further, in the case of sealing by welding the CPP 30 μ surface and the OPP 20 μ surface, the pressing force of the heater is strengthened and the seal strength is increased by making the seal portion 6 a discontinuous point or a discontinuous line as shown in FIG. Even if it is used as a bag for carrying, it will not crack from here.

Although the bottom portion 2 has a trapezoidal shape in FIG. 1, when the bag body 1 is filled with an object, the bottom portion 2 has a square bottom as shown in FIG.

Next, the same experiment was performed on the above-described experimental example of the present invention for Comparative Examples 1 and 2 as described below, and the method and the result are shown.

Comparative Example 1 A packaging bag similar to that of the embodiment of the present invention except that the same two-layer film as that of the embodiment is used and the upper and lower films of the opening are respectively folded back inward to form a handbag (reinforcing portion). made. This is because the sealing strength of the reinforcing portion B is weak because the OPPs are welded to each other, and it is easy to tear at this portion, so that it cannot be practically used as a packaging bag.

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

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

[0022]

[Table 1]

[0023]

[Effect of the invention]

 Since the present invention is configured as described above, the following effects can be obtained. 1) A packaging bag can be manufactured from one type of film. 2) The strength of the left and right seal parts can be increased by folding the CPP outward. 3) Strength can be improved by making the seal between the bag body and the folded-back reinforcing portion discontinuous.

[Brief description of the drawings]

FIG. 1 is an external view of an embodiment of a packaging bag according to the present invention.

FIG. 2 is an enlarged sectional view taken along line XX of FIG.

FIG. 3 is a perspective view of the packaging bag of FIG. 1 unfolded and viewed from the bottom.

[Explanation of symbols]

 1 Bag body 2 Bottom part 3 Opening part 4 Reinforcing part 5 Hole 6 Seal part

Claims (3)

[Utility model registration claims] 1. A bag main body formed into a bag shape by folding back the bottom portion of a two-layer film composed of a cast polypropylene film and a biaxially oriented polypropylene film and heat-welding the left and right ends by fusing, and an opening of the bag body. The left and right ends are heat-welded by fusing when the bag body is formed, and the width part is sealed and integrated with the bag body when the bag body is formed. In the packaging bag having the hole for carrying a bag, the cast polypropylene film side of the two-layer film constituting the bag body is located inside the bag, and the reinforcing portion extends from the opening of the bag body. A packaging bag, characterized in that it is formed by folding back the cast polypropylene film portion provided on the outside. 2. The packaging bag according to claim 1, wherein the bottom of the bag body is a square bottom. 3. The packaging bag according to claim 1, wherein the longitudinal seal between the bag body and the reinforcing portion is a discontinuous point or a discontinuous line.