JP3202184B2 - Manufacturing method of square bottom bag with inner bottom - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a square bottom bag with an inner bottom.

Heretofore, bags using a heat-weldable synthetic resin sheet of polyethylene or the like have been widely used because of their simple manufacturing. As the bag made of a synthetic resin sheet that can be welded by heating, a bag provided with a bent gore portion that is previously bent inward on both left and right sides, which is called a square bottom bag, is also widely used.

The heat-weldable synthetic resin sheet made of a square bottom bag will be described with reference to the attached FIG. 3 showing an embodiment of the present invention. The rear surface portion 10b is connected by bent gore portions 11a, 11b which are depressed and bent inward on both left and right sides thereof, and further, both bottom sides 12, 12 of the front surface portion 10a and the rear surface portion 10b are folded therebetween. Bend gore part 11
A and 11b are heat-welded together with the bottom portions 13, 13, 13, 13 (see FIG. 2) at the bottom seal line portion H1 (see FIG. 1).

[0004] Therefore, this square bottom bag is connected to the front part 10.
When the three-dimensional shape is formed so that the a and the rear surface portion 10b are separated from each other by a predetermined distance, as shown in FIG. 3, a substantially rectangular parallelepiped shape having a rectangular bottom surface 10c is provided. . In addition, when forming into a substantially rectangular parallelepiped shape having the rectangular bottom surface 10c as described above, the bent gore portions 11a, 11b
At the bottom, there are formed gore bottom folded portions 13a and 13b which are folded inside in a triangular shape.

When the inner bottom 2 also shown in FIG. 3 is housed in the above-mentioned heat-sealable synthetic resin sheet square bottom bag, the shape retention is further improved. At present, it is often used.

However, this kind of conventional square bottom bag with an inner bottom has a problem that the inner bottom 2 may be moved from a predetermined location and the purpose of the inner bottom may not be achieved.

[0007] Further, it has been pointed out that, in the above-mentioned conventional square bottom bag with an inner bottom, as shown in Fig. 3, the bottom side of the bag falls away from the inner bottom 2 and the appearance is deteriorated. In addition,
In FIG. 3, the entire bottom of the bag is shown to hang below the inner bottom 2. However, when the inner bottom 2 is stored in a predetermined place, the bottom tends to be pressed against the lower surface of the inner bottom 2. However, since there are many layers of cloth on the left and right sides of the bottom of FIG. 3, the cloth on the lowermost side cannot be prevented from hanging down. When viewed from the left and right directions in FIG. However, there is a problem that a triangular hanging portion is formed on the rim and the appearance is deteriorated.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a structure in which the inner bottom is stored and fixed in a predetermined position in advance, and the inner bottom is not displaced. It is an object of the present invention to provide a method for manufacturing a square bottom bag with an inner bottom that has a small shape collapse by improving the shape.

[0009]

In order to achieve the above object, the present invention comprises, as a first step, forming a long cylindrical member 10A1 of a heat-sealable synthetic resin, and as a second step, forming the long cylindrical member 10A1. The cylindrical member 10A1 has a flat shape in which a front surface portion 10a and a rear surface portion 10b are overlapped with each other, and the left and right sides are bent inward to form bent gore portions 11a and 11b. A flat long bag material 10A2 is formed in such a manner that the upper and lower surfaces 10b are overlapped with each other and the left and right sides thereof are folded into a four-layer shape including the bent gore portions 11a and 11b.
As a third step, the long bag material 10A2 is welded under pressure and heat at predetermined intervals at the bottom seal line portion H1, and cut along a cutting line C1 parallel to the bottom seal line portion H1 to form the square bottom bag body 1. In the fourth step, a synthetic resin layer 21 which can be heat-welded to the lower surface side of the cardboard 20 in the square bottom bag body 1 in the fourth step.
Or the inner bottom 2 made of a thick thermoplastic synthetic resin plate is three-dimensionally housed so as to form a square bottom surface 10c in the square bottom bag main body 1, and as the fifth step, the three-dimensional corners are formed. The bottom bag body 1 is returned to a flat body such that the front portion 10a and the rear surface portion 10b are in a two-layered shape and the left and right sides are four-layered including the bent gore portions 11a and 11b.
The rectangular bottom surface 10c is folded together with the inner bottom 2 so as to overlap the front surface portion 10a or the rear surface portion 10b and flattened again. As a sixth step, the rectangular bottom surface line H2 parallel to the bottom seal line portion H1 is formed into a square shape. When forming the rectangular bottom surface 10c, the bottom surface 10c and the inner bottom 2 are bent to form bent gore portions 11a, 11b.
gore bottom folded part 13a with the bottom of b folded inside,
Along with 13b, a technical measure is taken to weld the lower surface of the inner bottom 2 by pressurizing and heating.

Therefore, the method for producing a square bottom bag with an inner bottom according to the present invention has the effect of forming the conventionally known square bottom bag body 1 in the third step from the conventionally known first step. The inner bottom 2 accommodated in the fourth step is formed by laminating a heat-sealable synthetic resin layer 21 on the lower surface side of the cardboard 20 or using a thick thermoplastic synthetic resin plate. In the sixth step, an effect of welding to the square bottom surface 10c is exhibited, and in the fifth step, flattening is performed. Therefore, in the sixth step, an effect capable of being welded by a conventional thermocompression bonding apparatus is exhibited.

[0011]

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the method of the present invention, as a first step, a long tubular member is formed of a synthetic resin which can be welded by heating. This long tubular material may be formed into a continuous tubular body in advance by an inflation method, or may be formed into a long tubular shape by welding both ends in the short direction of a synthetic resin sheet of a long sheet. Things.

In the second step, the long cylindrical member is formed into a flat shape in which a front portion 10a and a rear surface portion 10b are overlapped with each other, and both right and left sides are bent inward to be bent. 11a and 11b to form the front portion 10a
The flat and long bag material 10A1 is formed so that two sheets are overlapped with the rear face part 10b, and the left and right sides thereof are four sheets including the bent gore parts 11a and 11b.

The bent gore portions 11a and 11b are formed by appropriately folding a predetermined width inward by a guide plate or the like during the transfer of the long tubular material wound in a roll shape while rewinding the material. This can be performed by a conventionally known method.

Next, as a third step, the long bag material 10A1 is pressure-heated and welded at a predetermined interval at a bottom seal line H1, and cut along a cutting line C1 parallel to the bottom seal line H1. A square bottom bag body 1 is formed. Pressing and heating welding at the bottom seal line portion H1 and cutting at the cutting line C1 can also be performed by a conventionally known device and method. The long cylindrical material is intermittently transferred, and when the transfer is stopped, the long cylindrical material 10A1 is stopped. A seal press tool and cutting teeth are provided to cross the long cylindrical member 10.
The seal pressing tool and the cutting teeth may be intermittently operated in conjunction with the intermittent transfer distance of A1.

The above-mentioned first to third steps are the same as the conventional manufacturing method using a square bottom bag, but in the present invention, in the fourth step, the lower surface of the cardboard 20 is placed in the aforementioned square bottom bag body 1. A heat-weldable synthetic resin layer 21 is laminated on the side, or the inner bottom 2 made of a thick thermoplastic synthetic resin plate 2a is three-dimensionally housed in the square bottom bag main body 1 so as to form a square bottom surface 10c. It is done.

At present, the inner bottom 2 is stored by hand in the present embodiment because no suitable device has been developed. In this case, the cost is not particularly increased as compared with the conventional method since the operation is performed manually.

In a fifth step, the three-dimensional square-bottomed bag body 1 is formed by stacking four front and rear portions 10a and 10b on both left and right sides including bent gore portions 11a and 11b. While returning to the flat body so that it becomes a shape,
The rectangular bottom surface 10c is folded together with the inner bottom 2 so as to overlap the front surface portion 10a or the rear surface portion 10b, and flattened again. That is, as shown most clearly in FIG. 4, the rectangular bottom surface 10c is further overlapped with the overlapped front surface portion 10a and rear surface portion 10b. The work to return to flattening is the same as before, and since flattening reduces the volume and is convenient for transportation and storage, it is usually traded as a product in this flattened state. is there.

Further, in the present invention, as a sixth step, the square bottom surface 10c and the inner bottom 2 are formed by the inner bottom fixed seal line H2 parallel to the bottom seal line portion H1 to form the square bottom surface 10c. At this time, the bottoms of the bent gores 11a and 11b are folded inward and the gore bottom bent portions 13a and 13b are welded together by pressing and heating to the lower surface of the inner bottom 2.

That is, in the fifth step, the square-bottomed bag body 1 has been returned to the flat state as shown in FIG. 4, so that a fixing member is appropriately arranged on the left side of FIG. The tip of a well-known seal press is connected to the inner bottom fixed seal line segment H2.
The square bottom bag main body 1 may be pressed and heated so as to be fitted to the part so as to be sandwiched between the main body 1 and the fixing member.

[0020]

According to the method of the present invention as described above, it is possible to provide a square bottom bag with an inner bottom in which the inner bottom 2 is fixed so as not to be displaced.

In order to fix the inner bottom 2, a synthetic resin layer 21 which can be welded by heat is laminated on the lower surface side, or the inner bottom 2 made of a thick thermoplastic synthetic resin plate is used. The present invention can provide a square bottom bag with an inner bottom that can be easily and securely fixed by a conventional heating method. In particular, according to the method of the present invention, the synthetic resin layer 21 capable of heat welding the inner bottom 2 to the lower surface side
Or using a thick thermoplastic synthetic resin plate, and welding the rectangular bottom surface 10c and the inner bottom 2 to the lower surface of the inner bottom 2 together with the gore bottom folded portions 13a and 13b by pressing and heating. Except for this point, the conventional method of manufacturing each bottom bag can be used, so that it is possible to provide a method of manufacturing a square bottom bag with an inner bottom without a large increase in manufacturing cost.

In the method of the present invention, since the bag body 1 is returned to the flattened state in the fifth step, in the sixth step, the above-mentioned welding can be performed by a conventionally known simple thermocompression bonding apparatus. It is possible to provide a method for manufacturing a square bottom bag capable of manufacturing a square bottom bag with an inner bottom having high commercial value simply by increasing only one step.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view of a square bottom bag obtained by the method of the present invention.

FIG. 2 is a perspective view of a main part of a manufacturing process illustrating the method of the present invention.

FIG. 3 is a perspective view of a main part in the middle of manufacturing after cutting in FIG. 2;

FIG. 4 is a perspective view of a main part in the middle of manufacturing after the inner bottom is housed in FIG.

FIG. 5 is a longitudinal sectional view of a bottom piece of the square bottom bag of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Square bottom bag main body 2 Inner bottom 10a Front part 10b Rear part 10c Square bottom 10A1 Flat long bag material 11a Folded gore part 11b Folded gore part 12 Bottom part 13 Bottom part 13a Gore bottom folded part 13b Gore bottom folded part 20 Cardboard 21 Synthetic resin layer C1 Cutting line H1 Bottom seal line H2 Inner bottom fixed seal line

Claims (1)

(57) [Claims] In a first step, a long tubular material (10A1) is formed from a heat-sealable synthetic resin, and in a second step, the long tubular material is formed by a front part (10a) and a rear part (10b). And the left and right sides are bent inwardly to form bent gore portions (11a, 11b), and the front surface portion (10a) and the rear surface portion (10b) are formed. Is formed into a two-ply shape, and a flat long bag material (10A1) is formed so as to form a four-ply shape including the bent gore portions (11a, 11b) on both left and right sides. (10A1) is pressed and heated and welded at a bottom seal line (H1) at a predetermined interval, and a cutting line (C) parallel to the bottom seal line (H1) is formed.
Cut in 1) to form a square bottom bag body (1), and in a fourth step, a cardboard (20) is placed in the square bottom bag body (1).
A heat-weldable synthetic resin layer (21) is laminated on the lower surface side of the inner surface, or an inner bottom (2) made of a thick thermoplastic synthetic resin plate
Is stored in a three-dimensional manner so as to form a square bottom surface (10c) in the square bottom bag body (1). As a fifth step, the three-dimensional square bottom bag body (1) is
The front part (10a) and the rear part (10b) are overlapped with each other, and the left and right sides thereof are returned to a flat body so as to form four sheets including the bent gore parts (11a, 11b). 10c) is folded together with the inner bottom (2) so as to overlap the front surface (10a) or the rear surface (10b) and flattened again. As a sixth step, the inner bottom is fixed parallel to the bottom seal line (H1). With seal line (H2), square bottom (10c)
And the inner bottom (2) together with the gore bottom folded portions (13a, 13b) into which the bottoms of the bent gore portions (11a, 11b) are folded inward when forming the rectangular bottom surface (10c). 2) A method for producing a square-bottomed bag with an inner bottom, which is welded by applying pressure and heat to the lower surface.