JPH11124145A - Rectangular bottom bag with inner bottom and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rectangular bottom bag having an inner bottom part and a method of manufacturing it in which an inner bottom part is stored and fixed at a predetermined position, the inner bottom part is not displaced, its shape holding characteristic is improved and its form destruction is low. SOLUTION: This bag is comprised of a main body 1 of a rectangular bottom bag and an inner bottom 2 formed by a synthetic resin layer which can be heated and melted against a lower surface of a thick sheet and laminated on the main body or formed by a thick thermoplastic synthetic resin plate. The inner bottom 2 is stored in the main body 1 of a rectangular bottom bag and a rectangular bottom surface 10c is formed at the bag main body 1, thereafter parts of the rectangular bottom surface 10c and the inner bottom 2 are melted and adhered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

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 a three-dimensional shape is formed such 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, and when viewed from the left and right directions in FIG. 3, the lower parts of the bent gores 11 a and 11 b 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 square bottom bag with an inner bottom and a method of manufacturing the same, which is less likely to lose its shape.

[0009]

In order to achieve the above object, the construction of the present invention is a heat-sealable synthetic resin sheet in which the front part 10a and the rear part 10b are respectively depressed inward on both left and right sides thereof. The bent gore portions 11a, 11b are connected by the bent gore portions 11a, 11b, and the bottom gore portions 12, 12 of the front surface portion 10a and the rear surface portion 10b are further folded therebetween.
Whether the square bottom bag main body 1 formed by heat welding at the bottom seal line portion H1 together with each of the bottom portions 13, 13, 13, and 11 b of the base material 11 b and the synthetic resin layer 21 that can be heat welded to the lower surface side of the cardboard 20 The inner bottom 2 is made of a thick thermoplastic synthetic resin plate. The inner bottom 2 is housed in the square-bottomed bag body 1, and a square bottom surface 10c is formed in the bag body 1. And a part of the inner bottom 2 is pressurized, heated and welded by technical means.

Therefore, the square bottom bag with the inner bottom according to the present invention is non-displaceably welded and fixed to the square bottom surface 10c with the inner bottom 2 interposed through the lower surface synthetic resin layer 21 or directly in the case of a thermoplastic synthetic resin plate. It has the effect of being performed.

Next, a second aspect of the present invention relates to a synthetic resin sheet which can be welded by heating, wherein a front portion 10a and a rear portion 10b are provided.
Are connected by bent gore portions 11a and 11b which are depressed and bent inward on both left and right sides, respectively, and further, bent gores which are folded between both bottom side portions 12 and 12 of the front surface portion 10a and the rear surface portion 10b therebetween. Each of the bottom portions 13, 13, of the portions 11a, 11b,
Square bottom bag main body 1 formed by heat welding at bottom seal line portion H1 together with 13 and 13, and heat-sealable synthetic resin layer 21 laminated on the lower surface side of cardboard 20 or made of thick thermoplastic synthetic resin plate After the inner bottom 2 is housed in the square bottom bag main body 1 and the rectangular bottom surface 10c is formed in the bag main body 1, the inner bottom fixed seal parallel to the bottom seal line H1 is formed. At the line segment H2, the rectangular bottom surface 10c and the inner bottom 2 are bent to form bent gore portions 11a, 11b when forming the rectangular bottom surface 10c.
Gore bottom folds 13a, 1
In addition to 3b, a technical measure is adopted in which the lower surface of the inner bottom 2 is welded by pressurizing and heating.

Therefore, in addition to the above-described operation, the square bottom bag with bent bottoms 13a and 13b formed by bending the bottoms of the bent gores 11a and 11b inwardly has
0c, it has an effect of being welded and fixed to the lower surface of the inner bottom 2.

Next, according to the invention of claim 3, as the first step, the long cylindrical member 10A1 is formed of a heat-sealable synthetic resin, and as the second step, the long cylindrical member 10A1 is attached to the front part. 10a and the rear surface portion 10b form a two-layered flat shape, and the left and right side portions thereof are bent inwardly and bent to form bent gore portions 11a and 11b, and the front surface portion 10a and the rear surface portion 10b are formed. A flat long bag material 10A2 is formed so as to be a four-layered shape including two bent portions 11a and 11b on both left and right sides. As a third step, the long bag material 10A2 is formed at a predetermined interval. The bottom seal line portion H1 is pressurized and heated 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, the inside of the square bottom bag body 1 is formed. The heat-sealable sheet on the lower surface of the cardboard 20. A resin layer 21 is laminated, 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 body 1, and as the fifth step, the three-dimensional The formed square bottom bag body 1 is returned to a flat body such that the front portion 10a and the rear surface portion 10b are two-layered and the left and right sides are four-layered including the bent gore portions 11a and 11b. Square bottom 10c is inner bottom 2
At the same time, it is bent so as to overlap with the front surface portion 10a or the rear surface portion 10b and flattened again. 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. When the rectangular bottom surface 10c is formed, the bottom of the bent gore portions 11a and 11b is folded inward together with the gore bottom folded portions 13a and 13b to be welded to the lower surface of the inner bottom 2 by heating under pressure. Technical measures taken.

Therefore, the method for producing a square bottom bag with an inner bottom according to the present invention has the function of forming the conventionally known square bottom bag body 1 in the third step from the first step of the conventional method. 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.

[0015]

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The square bottom bag with an inner bottom according to the present invention includes a square bottom bag main body 1 and an inner bottom 2.

The above-mentioned square-bottomed bag main body 1 is a conventionally known synthetic resin sheet which can be heated and welded. A bent gore portion is formed by bending the front surface portion 10a and the rear surface portion 10b inward on both left and right sides, respectively. 11a and 11b, and the front part 1
0a and the back surface portion 10b, the bottom portions 12, 12 of the bent gore portions 11a, 11b into which the bottom portions 12, 12 are folded.
13, 13, and 13 are heated and welded at the bottom seal line portion H1.

Polyethylene is most typically used as the heat-sealable synthetic resin sheet, and polyethylene can be easily manufactured into a long tubular body having a predetermined thickness and a predetermined width by an inflation method. What is necessary is just to use what was shape | molded in a cylindrical shape, it is sufficient to flatten a cylindrical shape, to indent a predetermined width | variety on both sides inward, and to bend it into two folds, and to form bent gore parts 11a and 11b. However, it goes without saying that a sheet-shaped synthetic resin sheet may be used, and both ends thereof may be welded into a cylindrical shape.

The front portion 10a and the rear portion 10b
When both the bottom sides 12 and 12 of the bent gore parts 11a and 11b are heated and welded together with the bottom sides 13, 13, 13, and 13 of the bent gore parts 11a and 11b between the bottom seal line parts H1, the bent gore parts 11a and 11b are bent. It is well known that the width of the square bottom bag is equal to the thickness of the square bottom bag, in other words, the square bottom bag main body 1 having the width in the lateral direction of the square bottom surface 10c of the square bottom bag described later.

When welding at the bottom seal line portion H1, the gore bottom oblique seal lines H3, H3, H shown in FIG.
3 and H3, one side surface of each of the concave and folded portions of the bent gore portions 11a and 11b is welded to the front surface portion 10a or the rear surface portion 10b which overlaps each one surface in FIG. 2 (this portion). Is a front part 10a, a rear part 10b, and both bent gore parts 11
a, 11b, but the four pieces are not welded together, but the left and right half surfaces of the bent gore part 11a and the two-piece overlap part such as the front face part 10a are respectively welded. It is. ), The gore seal lines H3, H3, H3, H3
It is also a conventionally known technique that a guide can be easily formed to form a desired accurate rectangular bottom surface 10c.

It is also conventionally known that the inner bottom is housed in the above-mentioned square bottom bag body 1. Conventionally, thick paper is used for the inner bottom. Either a layer formed by laminating a synthetic resin layer 21 that can be welded on the lower surface side or a thick thermoplastic synthetic resin plate 2a is used.

The inner bottom 2 in which the synthetic resin layer 21 which can be welded by heat is laminated on the lower surface side of the cardboard 20 is used so that the inner bottom 2 and the lower surface of the cardboard 20 can be welded by a conventional pressure and heat welding apparatus. The lamination of the synthetic resin layer 21 may be performed by a conventionally known laminating method or the like.

Incidentally, since the synthetic resin layer 21 is not laminated on the upper surface side of the cardboard 20, it is not welded to the square bottom bag main body 1. Further, as the thick thermoplastic synthetic resin plate, a polyethylene plate or the like can be used, and the thickness thereof is obtained by pressing a seal pressing tool having a heat source from the outside of a rectangular bottom surface 10c described below, which overlaps the lower surface side of the inner bottom 2. At the time, square bottom 1
0c is welded to the lower surface side of the inner bottom 2, but the heat of this seal presser is not transmitted to the upper surface side of the inner bottom 2 as much as the square bottom bag body 1 overlapping thereover is welded. Choose one.

After the inner bottom 2 is housed in the square bottom bag body 1 and a rectangular bottom surface 10c is formed in the bag body 1, a part of the square bottom surface 10c and the inner bottom 2 is pressurized and heated. And welded. The welding between the square bottom surface 10c and the inner bottom 2 can be performed by using a conventionally known pressure-heating type welding device called a heat sealer, and a seal pressing tool (heat bar) having a heat source is attached to the outside of the square bottom surface 10c. It may be welded by pressing against the inner bottom 2 from the side.

Next, in the invention of "Claim 2", the same square bottom bag body 1 and inner bottom 2 are used as in "Claim 1". After storing and forming the square bottom surface 10c in the bag body 1, the square bottom surface 10c and the inner bottom 2 are connected to each other by the inner bottom fixed seal line H2 parallel to the bottom seal line portion H1. It is formed by pressurizing and heating the lower surface of the inner bottom 2 together with the gore bottom folded portions 13a and 13b in which the bottoms of the bent gore portions 11a and 11b are folded inward.

That is, the inner bottom fixed seal line segment H2
Extends over the entire length of the rectangular bottom surface 10c in the longitudinal direction. At both end portions, the gore bottom folded portions 13a and 13b in which the bottoms of the bent gore portions 11a and 11b are folded inward are also formed along with the square bottom surface 10c. 2 to be integrally welded. Since the gore bottom folded portions 13a and 13b have a two-ply triangular tongue shape as shown in FIG. 3, the trigonal tongue and the square bottom face 10c as shown in the lower left portion of FIG. The three sheets are integrally welded to the lower surface of the inner bottom 2 at a time.

Next, in the method of the present invention according to claim 3, as the first step, a long cylindrical material 10A made of a heat-sealable synthetic resin is used.
Form one. As described above, the continuous tubular body 10A1 may be formed by molding a continuous tubular body in advance by an inflation method, or by welding both ends of the long synthetic resin sheet in the short direction. It may be.

In the second step, the long cylindrical member 1 is used.
The front part 10a and the rear part 10b are formed by forming the front part 10a and the rear part 10b into a flat shape in which the front part 10a and the rear part 10b are overlapped with each other, and bending the left and right side parts inwardly to form bent gore parts 11a and 11b. The flat long bag material 10A2 is formed so that the surface portion 10b and the left and right sides thereof are four-layered including the bent gore portions 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 cylindrical material 10A1 wound in a roll shape while being rewound. Can be performed by a conventionally known method.

Next, as a third step, the long bag material 10A2 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.
1 is intermittently transferred, and at the time of transfer, a seal pressing tool and cutting teeth are provided to cross the long cylindrical member 10A1, and the long cylindrical member 1A is provided.
The seal pressing tool and the cutting teeth may be intermittently operated in conjunction with the transfer distance of 0A1.

The first to third steps are the same as those of the conventional method for manufacturing a square bottom bag, but in the present invention, in the fourth step, the lower surface of the cardboard 20 is placed in the 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.

The inner bottom 2 is stored by hand in the present embodiment because an appropriate device has not been developed at present. In this case, the cost is not particularly increased as compared with the conventional method since the operation is performed manually.

As 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. This flattening operation is the same as the conventional operation. Flattening reduces the volume and is convenient for transportation and storage, so 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, since the square-bottomed bag main body 1 has been returned to the flat state as shown in FIG. 4 in the fifth step, 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.

[0035]

According to 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 heated and welded 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.

Further, in addition to the above-described effects, the invention of claim 2 provides the rectangular bottom surface 10c and the inner bottom 2 with the rectangular bottom surface 10c.
When forming the c, the bottoms of the bent gore portions 11a and 11b are folded inward together with the gore bottom folded portions 13a and 13b.
Since the lower surface of the inner bottom 2 is pressed and heated and welded, the gore bottom folded portions 13a and 13b are welded and fixed to the lower surface of the inner bottom 2 together with the square bottom surface 10c, and both sides of the square bottom surface 10c hang downward. The present invention can provide a square bottom bag with an inner bottom that does not have a good appearance.

The method according to the third aspect of the present invention relates to a method of laminating a synthetic resin layer 21 capable of heat welding the inner bottom 2 on the lower surface side,
A point made of a thick thermoplastic synthetic resin plate is used.
a, 13b, except that they are welded by pressurizing and heating to the lower surface of the inner bottom 2 so that conventional methods for producing each bottom bag can be used.
It is possible to provide a method of manufacturing a square bottom bag with an inner bottom without a significant increase in manufacturing cost.

In the method of the present invention, the bag body 1 is returned to the flattened state in the fifth step, so that in the sixth step, the above-mentioned welding can be carried out 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 according to 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 cut off in FIG. 3;

FIG. 5 is a vertical cross-sectional view of a bottom part 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 surface 10A1 Long tubular material 10A2 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 (3)

[Claims] 1. A synthetic resin sheet which can be welded by heating, wherein a front part (10a) and a rear part (10b) are bent inwardly and depressed inward on both left and right sides thereof.
b), and the front part (10a) and the rear part (1)
0b) and the bottom portions (13, 1) of the bent gore portions (11a, 11b) between which both bottom portions (12, 12) are folded.
3, 13 and 13) and a square bottom bag body (1) formed by heat welding at the bottom seal line (H1), and a synthetic resin layer (2) heat weldable on the lower surface side of the cardboard (20).
1) or an inner bottom (2) made of a thick thermoplastic synthetic resin plate. The inner bottom (2) is housed in the square bottom bag body (1), and the bag body ( 1) A square bottom bag with an inner bottom formed by forming a rectangular bottom surface (10c) on the rectangular bottom surface (10c) and welding a part of the rectangular bottom surface (10c) and the inner bottom (2) by heating under pressure. 2. A heat-weldable synthetic resin sheet, wherein a front part (10a) and a rear part (10b) are bent inwardly on both left and right sides thereof so as to be bent inward.
b), and the front part (10a) and the rear part (1)
0b) and the bottom portions (13, 1) of the bent gore portions (11a, 11b) between which both bottom portions (12, 12) are folded.
3, 13 and 13) and a square bottom bag body (1) formed by heat welding at the bottom seal line (H1), and a synthetic resin layer (2) heat weldable on the lower surface side of the cardboard (20).
1) or an inner bottom (2) made of a thick thermoplastic synthetic resin plate. The inner bottom (2) is housed in the square bottom bag body (1), and the bag body ( After the square bottom surface (10c) is formed in 1), the square bottom surface (10c) and the inner bottom (2) are separated by the inner bottom fixed seal line (H2) parallel to the bottom seal line portion (H1). When forming the square bottom surface (10c), the bent gore portion (11
A square bottom bag with an inner bottom, which is heated and welded to the lower surface of the inner bottom (2) together with the gore bottom folded portions (13a, 13b) with the bottoms of the a and 11b) folded inside. 3. As a first step, a long tubular member (10A1) is formed of a heat-sealable synthetic resin, and in a second step, the long tubular member (10A1) is attached to a front part (10a) and a rear part. (10b) are formed into a two-layered flat shape, and the left and right side portions are bent inwardly to form bent gore portions (11a, 11b), and the front surface portion (10a) and the rear surface portion (11a) are formed. 10b) to form a flat and long bag material (10A2) so that the left and right sides thereof are four-layered including the bent gores (11a, 11b). The shakubag material (10A2) is pressure-heated and welded at predetermined intervals at the bottom seal line (H1), and a cutting line (C) parallel to the bottom seal line (H1).
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.