JPH05178355A - Bag made of synthetic resin sheet and manufacture thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] When both ends of the gusset are expanded, the expansion is not restricted by the welded parts, and the manufacturing is easy. [Composition] In a bag made of a synthetic resin sheet in which synthetic resin sheets are folded in two and superposed, and both side edges of the superposed sheet are joined by a welding portion, a town having a V-shaped cross section is provided at the folded-back portion serving as a bottom portion. A bent portion having a W-shaped cross section is formed, and the outer edges of the corners of the respective gussets, which are formed by obliquely cutting the corners on both sides, are joined to each other by welding, and the gussets are independent of each other. It is characterized in that it is configured to spread.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin sheet bag which can be used as a small bag such as a futon cover and an improvement in its manufacturing method.

[0002]

2. Description of the Related Art As shown in FIG. 6, a conventional method of manufacturing a synthetic resin bag is such that a synthetic resin sheet 61 is folded back and overlapped with each other, and the folded back sheet is bent into a W-shaped cross section. 62 was formed, and then, as shown in FIG. 7, both sides of the folded sheet 61 were linearly joined at the welded portion 63 including the folded portion.

However, according to such a manufacturing method, when a thick product is put at the bottom of the manufactured bag, the spread of both ends of the gusset is restricted by the welding portions 63, so that the space at the bottom of the bag is limited. There was a problem that could not be fully utilized. Therefore, as shown in FIG.
The sheet portion 82 which is the bottom of the bag of 1 is cut in advance,
Next, as shown in FIG. 9, a method of joining two sheets 83 and 84 at a welded portion 85 has been proposed.

However, such a method has a problem in that a complicated cutting process is added and the welding work is complicated, resulting in an increase in manufacturing cost.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to restrict the spread at the welded part when both ends of the gusset are expanded. It is an object of the present invention to provide a synthetic resin bag and a manufacturing method thereof, which is free from the above and is easy to manufacture.

[0006]

A synthetic resin bag according to claim 1, wherein the synthetic resin sheet is folded in two and superposed, and both side edges of the superposed sheet are joined by welding portions. In the above, the bent portion having a W-shaped cross section in which the gusset portion having a V-shaped cross section is formed is formed in the folded-back portion serving as a bottom portion, and the outer edge of the corner portion of each gusset portion is cut diagonally on both sides. Are welded to each other and the respective gussets are independently expanded.

According to a second aspect of the present invention, there is provided a method of manufacturing a synthetic resin sheet bag, wherein synthetic resin sheets are folded back and overlapped with each other, and the sheet at the folded back portion is formed into a W-shaped cross section such that the V-shaped cross section is continuous. Along with folding, the sheets of this gusset are overlapped, then a release paper is interposed between these gussets from the outside, then the corners of both ends of each gusset are welded diagonally, and the folded sheet Both sides are welded, and the corners at both ends of each gusset are cut along the outer edge of the weld.

[0008]

According to the synthetic resin sheet bag product of claim 1 of the present invention, when the bag product is expanded for storage, as shown in FIG. 5, the welded portions of the side edges of the bag and the welded portions of the gusset portion are reversed. It spreads out in a Y shape, and the diagonal cut portion is located on the side surface of the bottom portion of the bag. That is, since both ends of the gusset are cut obliquely and are connected by the welded portions, there is no room for wrinkles when the bottom is expanded, and the space at the bottom can be effectively used.

According to the method of manufacturing a synthetic resin sheet bag according to the second aspect, since the release paper is interposed between the gussets, when the corners at both ends of each gusset are obliquely welded,
Even if the gussets are overlapped and welded, the gussets are not joined to each other.

[0010]

EXAMPLES A synthetic resin bag and a method for producing the same according to the present invention will be described below with reference to the illustrated examples. 1 to 4 show a manufacturing process of the bag 1 made of a synthetic resin sheet. First, the synthetic resin sheet 1 is folded back by an automatic folding machine, and the sheet at the folded back portion is bent into a W-shaped cross section so that the gusset portions 2 having a V-shaped cross section are continuous (FIG. 1). Stack the two sheets (Fig. 2).

Next, the release paper B is placed between these gussets 2.
Intervene. Next, the folded sheet 4 is welded by high frequency welding means (not shown) (FIG. 4). That is, the folded sheet 4 is inserted between both electrodes of the high frequency welding means with the release paper B interposed. Then, the corner portions 3 at both ends of each town portion 2 are obliquely welded at an angle of 45 degrees to join the corner portions 3 to each other at the oblique welding portion 2A, and the base end portions of the both side portions 41 of the folded sheet 4 are joined together. These base ends are welded and joined at the side welded portions 4A.

At the same time, the base end portion at the lower end of the gusset portion 2 is also welded, and these base end portions are joined at the bottom end welded portion 2B. In addition, when welding these, the oblique welding portion 2A,
The outer peripheral portions of the folded sheet 4 are removed by fusing the outer edges of the lower end welded portion 2B and the side welded portion 4A. Note that the outer peripheral portion of the folded sheet 4 may be formed later by using a cutter or the like. Further, the welding means is not limited to one using high frequency.

The bag made of synthetic resin sheet thus manufactured has the following structure. That is, a bent portion 2A having a W-shaped cross section in which a gusset portion 2 having a V-shaped cross section is continuous is formed on the bottom portion 11 of the bag 1, and the corner portions 3 on both sides of the gusset portion 2 are obliquely cut. An oblique welded portion 2A is formed at the edge of the obliquely cut portion, and a lower end welded portion 2B is formed at the lower end of the gusset portion 2, and the bag 1
Side welded portions 4A are formed on both side edges of the.

Therefore, when a bag having a large thickness is put in the bag A, the bottom portion 11 has an inverted Y-shape with the side welded portion 4A of the bag 1 and the diagonal welded portion 2A of the gusset portion 2 as shown in FIG. The welded part of the bag 1 is formed, and the diagonal cut 12 is formed in the bag 1
Will be located on the side surface of the bottom portion 11 of the.

[0015]

According to the bag made of synthetic resin sheet according to the first aspect of the present invention, both ends of the gusset portion are cut obliquely and are connected by the welded portion. Therefore, when the bottom portion is expanded, The spread is not restricted by the welded portion, and the bottom space can be effectively used.

According to the method of manufacturing a synthetic resin sheet bag according to the second aspect, since the release paper is interposed between the gussets, when the corners at both ends of each gusset are obliquely welded,
Since the town portions can be overlapped and welded, the production efficiency can be improved and the production cost can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing one step of a method for producing a bag made of a synthetic resin sheet according to the present invention.

FIG. 2 is a perspective view showing one step of a method for producing a bag made of a synthetic resin sheet according to the present invention.

FIG. 3 is a perspective view showing one step of a method for producing a synthetic resin sheet bag product according to the present invention.

FIG. 4 is a perspective view of the synthetic resin sheet bag product of the present invention.

FIG. 5 is a perspective view showing a state in which a storage item is put into the bag made of the synthetic resin sheet of the present invention and expanded.

FIG. 6 is a perspective view showing a manufacturing process of a conventional bag made of a synthetic resin sheet.

FIG. 7 is a perspective view showing a conventional synthetic resin sheet bag product.

FIG. 8 is a perspective view showing a manufacturing process of another conventional bag made of a synthetic resin sheet.

FIG. 9 is a perspective view showing another conventional synthetic resin sheet bag product.

[Explanation of symbols]

 1 bag 2 town part 3 corner part 2A diagonal welding part 4B side welding part

Claims (2)

[Claims] 1. A synthetic resin sheet bag product in which synthetic resin sheets are folded in two and superposed, and both side edges of the superposed sheets are joined by welding portions. Forming a bent portion having a W-shaped cross section in which the corner portions on both sides are obliquely cut, the outer edges of the corner portions of the respective town portions are joined by welding portions to form the respective town portions. A bag made of a synthetic resin sheet, characterized in that it is configured to be expanded independently. 2. A synthetic resin sheet is folded back and overlapped, and the sheet at the folded back portion is bent into a W-shaped cross section so that the gusset portions having a V-shaped cross section are continuous, and the sheets at this gusset portion are overlapped, Next, release paper is interposed between these gussets from the outside, and then the corners at both ends of each gusset are obliquely welded together, and both sides of the folded sheet are welded together so that the corners at both ends of each gusset are welded together. A method for manufacturing a bag made of a synthetic resin sheet, characterized in that the portion is cut along the outer edge of the welded portion.