JPH06255657A - Self-sustainable square bag and production thereof - Google Patents

Abstract

PURPOSE:To provide a square bag and the production method thereof, which keeps well a self-sustained function and seals securely the contents. CONSTITUTION:Diagonal heat-adhesive belts 6a, b, c, d are formed at the underside of four corners defined by respective folds 5a, b, c, d at both sides of a 64 body 1. A bottom adhesion part 7 is formed so that the front face 3 and the rear face 4 are stuck to each other through the through holes 8 at the bottom of respective folds. A second heat adhesion part 10 getting in contact with the diagonal heat adhesion part and the bottom adhesion part are provided together with the diagonal neat adhesion part when forming it, in the distance 9 between the inside start point of the diagonal heat adhesion parts 6a, b, c, d and the through hole 8, in order to secure the sealing near the through holes by sealing again with heat the second adhesion part on forming the bottom adhesion part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-supporting square bag capable of reliably sealing contents while maintaining good self-supporting property of the bag, and a method for manufacturing the same.

[0002]

2. Description of the Related Art A so-called gusset type square bag in which both sides of a tubular body made of a film or sheet-like material whose inner surface is a heat-adhesive material is folded and slanted below the four corners formed by the folding parts. There is known a self-supporting square bag in which a band-shaped heat-bonding portion is provided, and the bottom portion of the tubular body including the folding portion is heat-bonded integrally in a band-shape to form a bottom bonding portion.

In such a square bag, a through hole or a notch is previously formed in the bottom portion forming each folding portion in the bag manufacturing process,
The bottom adhering portion is heat-bonded in the horizontal direction including the folding portions so that the front surface portion and the rear surface portion are adhered to each other at the bottom portion of the cylindrical body through the through holes or notches. Is known to form (see Japanese Utility Model Publication No. 57-3789). Since the front and rear surfaces of the square bag are adhered to each other at the bottom, the bottom is easily bent in one direction integrally, and when the contents are filled, it is self-supporting vertically and does not easily fall over sideways. It has the advantage that it is performed reliably.

[0004]

In the bag making process of the above-mentioned square bag, through holes or notches are formed at predetermined positions on the bottom part of each folding part, and the folding parts are formed by mutual folding. Although the positions are controlled so that the perforated positions are properly set within the bottom adhesive portion, the positions are not necessarily constant in a continuous bag-making process, and may be slightly displaced. That is, the through hole or notch (8) of the square bag (1) obtained as shown in FIG.
It may be formed at a position that extends off the edge.
In such a case, due to the weight of the contents filled in the bag, the sealing in the vicinity of the folded portion top (6e) of the obliquely formed band-shaped heat-bonded portion (6) is impaired ( Since the load of the contents is particularly applied to the vicinity of the top of the folding part, the seal at the part is easily damaged), and the contents containing water pass through the sealing part and reach the through hole or the cut (8) part, There is an inconvenience of causing leakage or leakage from the through hole or cut. An object of the present invention is to provide a self-supporting square bag capable of reliably sealing the contents while maintaining the self-supporting property of the bag without causing such inconvenience and a manufacturing method thereof.

[0005]

The present invention has been accomplished in order to achieve the above object. That is, the present invention folds both sides of a tubular body made of a film or sheet-shaped material whose inner surface is a heat-adhesive material, and forms band-shaped oblique heat-bonded portions below the four corners formed by the folded portions. At the same time, the tubular body including each of the folding portions is bonded so that the front surface portion and the rear surface portion are adhered to each other at the bottom portion of the cylindrical body through the through holes or notches formed in the bottom portions of the folding portions. In a self-supporting square bag having a bottom adhesive portion formed by heat-adhering the bottom portion thereof, from the inside starting point of the oblique heat adhesive portion to the position of the through hole or cut along the bottom adhesive portion. The self-standing square bag is characterized in that a second heat-bonding portion that is in contact with the oblique heat-bonding portion and the bottom heat-bonding portion is provided.

In manufacturing the above-mentioned square bag, the second thermal bonding portion is first provided together with the oblique thermal bonding portion when the oblique thermal bonding portion is formed, and then the bottom bonding is performed. By heat-sealing the second heat-bonded portion again when forming the portion, the second heat-bonded portion is firmly sealed,
The second heat-bonded portion can be reliably sealed without an extra step.

[0007]

In the self-supporting square bag according to the present invention, the slanted heat-bonded portion is provided between the inner starting point of the slanted heat-bonded portion and the position of the through hole or cut along the bottom-bonded portion. Since the second heat-bonding portion that is in contact with the bottom-bonding portion is provided, even if the seal near the top of the folded portion of the oblique heat-bonding portion is damaged and the content passes through this seal portion, the content remains It is blocked by the second heat-bonding portion and does not reach the through hole or the cut portion, and therefore does not leak or leak from the through hole or the cut portion.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a perspective view of an embodiment of a square bag according to the present invention, FIG. 2 is a front view of another embodiment, FIG. 3 is a plan view showing a shape of a heating plate 21, and FIG. 4 is a shape of a heating plate 22. It is a top view shown.

The bag body 1 is made of a film or sheet material whose inner surface is a heat-adhesive material such as polyethylene.
The back seal portion 2 overlaps and adheres to form a tubular body. Both sides of the front surface portion 3 and the rear surface portion 4 are folded, respectively, and below the four corners formed by the folding portions 5a, 5b, 5c, 5d, a strip-shaped heat extending approximately 45 ° diagonally from the top of the folding portion. Adhesive parts 6a, 6b, 6c, 6d
Are formed. The bottom part of the tubular body is heat-bonded in the horizontal direction including the folding parts to form the bottom bonding part 7,
Since the through holes or the cuts 8 are formed in the bottoms of the respective folding parts 5a, 5b, 5c, 5d, the bottom face of the tubular body is bonded to the front face part 3 and the rear face part 4 at the bottom. The adhesive portion 7 is formed. Reference numeral 13 is a side seal portion.

One of the features of the present invention is provided in the interval 9 from the starting point of the inside of the oblique thermal adhesive portions 6a, 6b, 6c, 6d to the position of the through hole or cut 8 along the bottom adhesive portion 7. A second heat-bonding portion 10 is provided. This second heat bonding portion 10
Are provided at a total of four locations so as to contact both the oblique heat-bonding portions 6a, 6b, 6c, 6d and the bottom bonding portion 7. In FIG. 1, the non-sealing portion 11 is left and formed in a strip shape in the vertical direction, but as shown in FIG. 2, the non-sealing portion may be provided so as to have a triangular shape without leaving the non-sealing portion. However, in any case, the second heat-bonding portion 10 has the oblique heat-bonding portion 6a,
It is important to form in the range from the inner starting point of 6b, 6c, 6d to the position of the through hole or notch 8 along the bottom adhesive portion 7. By sealing the entire area beyond the position of the through hole or notch 8 to the non-sealing portion 12 shown in FIG. 2, for example, the rigidity of the boundary portion with the bottom adhesive portion 7 increases,
When the contents are filled, the bottom adhesive portion 7 is less likely to bend and the self-supporting property of the bag is deteriorated. Therefore, the self-supporting property is maintained in a good range and the sealing is effective.

In manufacturing the above-mentioned square bag, it is possible to continuously manufacture the bag using a known manufacturing apparatus, but it is particularly advantageous to manufacture it by the following method. First, both ends of a long film or sheet material whose inner surface is a heat-adhesive material are overlapped and adhered to each other to form a tubular body, and the tubular body is transparent at the bottom positions forming the folding parts on both sides. Make holes or cuts. Then fold both sides. Then, band-shaped oblique thermal bonding portions are formed by pressing the heating plate below the four corners formed by the folding portions. When forming this oblique thermal bonding part, a second thermal bonding part is provided together with the oblique thermal bonding part. The heating plate 21 used at that time is shown in FIG.
It is preferable to use one having a shape corresponding to the oblique thermal bonding portion and the second thermal bonding portion as shown in the plan view.
Reference numeral 21a is a portion corresponding to the oblique heat-bonding portion, and 21b is a portion corresponding to the second heat-bonding portion. Reference numeral 21c is a temporary seal portion corresponding to the bottom adhesive portion. After that, the bottom bonding portion is formed by pressing the heating plate, and at this time, the second heat bonding portion is heat-sealed again. As a result, the bottom bonding portion is formed in a form in which the front surface portion 3 and the rear surface portion 4 are bonded to each other. The heating plate 22 used at this time preferably has a shape corresponding to the bottom adhesive portion and the second thermal adhesive portion as shown in FIG. Reference numeral 22a is a portion corresponding to the second heat-bonding portion, and can be slid laterally with respect to the portion 22b corresponding to the bottom bonding portion. Further, the bottom adhesive portion is cut into a bag. By such a method, the second heat-bonded portion is heat-sealed and firmly sealed again, and the second heat-bonded portion can be reliably sealed without an extra step.

[0012]

EFFECTS OF THE INVENTION According to the square bag of the present invention, when the position of the through hole or the cut of the square bag is formed so as to be out of the bottom adhesive portion and shifted, the top of the folded portion of the oblique heat adhesive portion is formed. Even if the seal in the vicinity is damaged, the contents are blocked by the second heat-bonding portion and do not reach the through hole or the cut portion, so that it is surely prevented from leaching and leaking from the through hole or the cut portion. Moreover, since the second heat-bonding portion is stopped within the range up to the position of the through hole or the notch along the bottom bonding portion, the bag can be held without lowering the self-supporting property of the bag when filling the contents. .

Further, in manufacturing the above-mentioned square bag, the second thermal bonding portion is first provided together with the diagonal thermal bonding portion when forming the diagonal thermal bonding portion, and then the bottom bonding portion is provided. When the second heat-bonded portion is heat-sealed again during the formation, the second heat-bonded portion is firmly sealed, so that the reliability of the seal can be improved without an extra step.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of a square bag according to the present invention.

FIG. 2 is a front view of another embodiment.

FIG. 3 is a plan view showing the shape of a heating plate 21.

FIG. 4 is a plan view showing the shape of a heating plate 22.

FIG. 5 is a front view illustrating an example using a conventional square bag.

[Explanation of symbols]

 1 bag body 2 back seal part 3 front face part 4 rear face part 5a, 5b, 5c, 5d folding part 6a, 6b, 6c, 6d oblique heat bonding part 7 bottom bonding part 8 through hole or notch 10 second heat bonding part 21,22 heating plate

Claims (2)

[Claims] 1. A tubular body made of a film or sheet material having an inner surface made of a heat-adhesive material is folded at both sides, and band-shaped oblique heat-bonded portions are formed below four corners formed by the folding portions. At the same time, in order to bond the front surface portion and the rear surface portion to each other at the bottom portion of the tubular body through the through holes or notches formed in the bottom portion of each folding portion, the tubular body including the folding portions is formed. In a self-supporting square bag in which the bottom portion is heat-bonded to form the bottom adhesive portion, from the inside starting point of the oblique heat adhesive portion to the position of the through hole or cut along the bottom adhesive portion, A self-supporting square bag having a second heat-bonding portion in contact with the oblique heat-bonding portion and the bottom heat-bonding portion. 2. The second thermal bonding portion is provided together with the oblique thermal bonding portion when the oblique thermal bonding portion is first formed,
The method for producing a self-supporting square bag according to claim 1, wherein the second heat-bonding portion is heat-sealed again when the bottom-bonding portion is formed.