JP2023108788A - packaging bag - Google Patents

Abstract

To provide a packaging bag which is easily manufactured and easily recycled.SOLUTION: The packaging bag is formed by thermally bonding peripheral edges of a first sheet 21, a second sheet 22, a third sheet 23 and a fourth sheet 24 which are laminated. The first sheet 21, the second sheet 22, the third sheet 23 and the fourth sheet 24 are made of polyolefin-based resins, and at least one of the opposing surfaces of the first sheet 21 and the third sheet 23 and at least one of the opposing surfaces of the second sheet 22 and the fourth sheet 24 are subjected to corona treatment.SELECTED DRAWING: Figure 2

Description

The present invention relates to packaging bags.

Articles such as semiconductor products, silicon wafers, magnetic disks, etc., do not like adhesion of foreign substances such as dirt, dust, and dust. These articles are then processed inside the clean room. These articles are often used inside clean rooms. Therefore, a packaging bag having a special structure is used in order to prevent foreign substances from adhering to articles during distribution and to prevent foreign substances from entering a clean room (see, for example, Patent Document 1).

A packaging bag used for such applications has a configuration in which a release film is arranged on the surface of the packaging bag. Then, the articles are placed inside the packaging bag, sealed, and distributed. In the distribution stage, the packaging bag may be contaminated with foreign matter. Before carrying the article into the clean room, the release sheet contaminated with foreign matter is peeled off, and the packaging bag with the clean inside is carried into the clean room. By doing so, entry of foreign matter into the clean room is suppressed.

Patent No. 5151555

However, in the case of the packaging bag of Patent Document 1, since a sheet obtained by laminating a base layer made of a biaxially oriented plastic film and a sealant layer made of a polyolefin resin is used, it takes time and effort to manufacture the sheet. In addition, it is difficult to recycle because it is made of a plurality of dissimilar materials.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a packaging bag that is easy to manufacture and easy to recycle.

In order to achieve the above object, the packaging bag of the present invention thermally bonds the peripheral edges of four laminated sheets. The packaging bag has a first sheet and a second sheet facing each other, a third sheet arranged outside the first sheet, and a fourth sheet arranged outside the second sheet. The first, second, third and fourth sheets are made of polyolefin resin. At least one of the facing surfaces of the first sheet and the third sheet and at least one of the facing surfaces of the second sheet and the fourth sheet are subjected to corona treatment.

In the packaging bag configured as described above, both the facing surfaces of the first sheet and the third sheet and the facing surfaces of the second sheet and the fourth sheet are corona-treated.

The packaging bag configured as described above has an unbonded portion, which is not thermally bonded, outside the thermally bonded portion.

In the packaging bag configured as described above, an unsealing start portion is provided at the heat-bonded portion of the first sheet and the second sheet.

In the packaging bag configured as described above, the third sheet and the fourth sheet have a higher heat resistance temperature than the first sheet and the second sheet.

In the packaging bag configured as described above, the first sheet, the second sheet, the third sheet, and the fourth sheet are all made of polyethylene.

In the packaging bag configured as described above, the first sheet, the second sheet, the third sheet, and the fourth sheet are all made of polypropylene.

In the packaging bag configured as described above, the first sheet and the second sheet are made of unstretched polypropylene. The third sheet and the fourth sheet are made of oriented polypropylene.

In order to achieve the above object, the packaging bag manufacturing apparatus of the present invention comprises: a first sheet and a second sheet facing each other; a third sheet disposed outside the first sheet; It is a packaging bag manufacturing apparatus for laminating a fourth sheet arranged outside the sheets and thermally bonding the peripheral edges of the four laminated sheets. The packaging bag manufacturing apparatus includes a first roll in which the first sheet is wound in a roll shape, a second roll in which the second sheet is wound in a roll shape, and a third sheet in which the third sheet is wound in a roll shape. It has a third roll, a fourth roll around which the fourth sheet is wound, and a heat-welding section that heats and presses simultaneously the peripheral edge portions of the four sheets that are pulled out from each of the rolls and stacked. The third roll, the first roll, the second roll and the fourth roll are arranged in this order. The third sheet is wound around the third roll so that the surface facing the first sheet is corona-treated. The first sheet is wound around the first roll so that the surface facing the third sheet is corona-treated. The second sheet is wound around the second roll so that the surface facing the fourth sheet is corona-treated. The fourth sheet is wound around the fourth roll so that the surface facing the second sheet is corona-treated.

According to the packaging bag of the present invention, it is possible to provide a packaging bag that is easy to manufacture and easy to recycle.

1 is a front view of one embodiment of a packaging bag according to the present invention; FIG. FIG. 2 is a schematic cross-sectional view of the packaging bag shown in FIG. 1; FIG. 4 is a front view showing a state in which the outer packaging is removed from the packaging bag; 1 is a schematic layout diagram of a packaging bag manufacturing apparatus; FIG. FIG. 10 is a schematic layout diagram of another example of the packaging bag manufacturing apparatus;

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of one embodiment of a packaging bag according to the present invention. 2 is a schematic cross-sectional view of the packaging bag shown in FIG. 1. FIG. FIG. 3 is a front view showing a state in which the exterior part 102 is removed from the packaging bag. As shown in FIG. 1, the packaging bag 100 is a rectangular bag, and is a four-sided seal pouch with four sides thermally bonded. In FIG. 1, the heat-bonded portion 11 is hatched with lanes. Also, the article Wh is indicated by a dashed line. The packaging bag 100 accommodates, for example, semiconductor products, silicon wafers, magnetic disks, and other articles that need to be prevented from being contaminated with dust or other foreign matter. The packaging bag 100 is used for transporting these articles.

The packaging bag 100 is formed by laminating and thermally bonding four sheets made of resin. The packaging bag 100 includes a first sheet 21 and a second sheet 22 arranged to face each other, a third sheet 23 arranged on the opposite side of the second sheet 22 with the first sheet 21 interposed therebetween, and the second sheet 22. and a fourth sheet 24 arranged on the side opposite to the first sheet 21 with the . The packaging bag 100 has a third sheet 23, a first sheet 21, a second sheet 22 and a fourth sheet 24 laminated in this order.

The packaging bag 100 has a bag body 101 having a housing space 10 surrounded by a first sheet 21 and a second sheet 22 and an exterior portion 102 made up of a third sheet 23 and a fourth sheet 24 .

The packaging bag 100 has an accommodation space 10 , a heat-bonded portion 11 , a notch portion 12 and a turn-over start portion 13 . The heat-bonded portion 11 is formed by heat-bonding adjacent sheets. The details of thermal adhesion will be described later. The accommodation space 10 is an area surrounded by the thermally bonded portion 11 between the first sheet 21 and the second sheet 22 .

In the packaging bag 100 according to this embodiment, the first sheet 21, the second sheet 22, the third sheet 23 and the fourth sheet 24 all have the same configuration. Therefore, the first sheet 21, the second sheet 22, the third sheet 23 and the fourth sheet 24 are made of polyolefin resin. By forming each sheet with a polyolefin-based resin, adjacent sheets can be heat-bonded by applying heat and pressure to each other.

As shown in FIG. 2, the outer surface of the first sheet 21 facing the third sheet 23 is a corona-treated surface 211 . Similarly, the outer surface of the second sheet 22 facing the fourth sheet 24 is a corona-treated surface 221 .

In addition, the inner surface of the third sheet 23 facing the first sheet 21 is a treated surface 231 that is subjected to corona treatment. Further, the inner surface of the fourth sheet 24 facing the second sheet 22 is a corona-treated surface 241 .

That is, as shown in FIG. 2, the inner surface 212 of the first sheet 21 and the inner surface 222 of the second sheet 22 which are not corona-treated face each other in the stacking direction. In addition, the treated surface 211 of the first sheet 21 and the treated surface 231 of the third sheet 23, and the treated surface 221 of the second sheet 22 and the treated surface 241 of the fourth sheet 24, which are corona-treated, are opposite.

After stacking the third sheet 23, the first sheet 21, the second sheet 22 and the fourth sheet 24 in this order, the peripheral edges of the third sheet 23 and the fourth sheet 24 are heated and pressurized from the outside. As described above, the first sheet 21, the second sheet 22, the third sheet 23 and the fourth sheet 24 are made of polyolefin resin. Therefore, the third sheet 23 , the first sheet 21 , the second sheet 22 and the fourth sheet 24 are heat-pressed and heat-bonded to form the heat-bonded portion 11 .

In the packaging bag 100, the article Wh is placed between the first sheet 21 and the second sheet 22, and the four sides are heat-sealed. Thereby, the article Wh is accommodated in the accommodation space 10, and the accommodation space 10 is sealed.

The corona-treated surface has the property that the bonding strength of the thermally bonded portion 11 is lower than that of the untreated surface. When four sheets are laminated, the facing surfaces of the third sheet 23 and the first sheet 21 are both subjected to corona treatment. In addition, the facing surfaces of the second sheet 22 and the fourth sheet 24 are both subjected to corona treatment. Therefore, the second adhesive portion 112 between the first sheet 21 and the third sheet 23 and the second adhesive portion 112 between the second sheet 22 and the fourth sheet 24 are the first adhesive portions between the first sheet 21 and the second sheet 22 . The adhesive strength is lower than that of the adhesive portion 111 . That is, the third sheet 23 and the fourth sheet 24 can be easily separated from the bag body 101 (see FIG. 3).

The turn-over starting portion 13 is provided at the lower end portion in FIG. 1, that is, outside the heat-bonded portion 11 when viewed from the stacking direction. In the turning start portion 13, the third sheet 23 and the first sheet 21 are not bonded. Also, the fourth sheet 24 and the second sheet 22 are not adhered. In addition, in the packaging bag 100 according to the present embodiment, neither the first sheet 21 nor the second sheet 22 is adhered.

With this configuration, the third sheet 23 and the first sheet 21 can be individually gripped at the turning start portion 13 . In this state, the third sheet 23 is moved away from the first sheet 21 and the second sheet 22 in the stacking direction. As described above, since the second adhesive portion 112 has a lower adhesive strength than the first adhesive portion 111, the separation between the first sheet 21 and the second sheet 22 is suppressed while the third sheet 23 is attached to the first sheet. 21 can be peeled off. Similarly, the fourth sheet 24 and the second sheet 22 can be individually gripped at the turning start portion 13 . Thereby, the fourth sheet 24 can be peeled off from the second sheet 22 .

In the packaging bag 100 of this embodiment, the outer surface of the first sheet 21 is the treated surface 211 and the inner surface of the third sheet 23 is the treated surface 231 . However, it is not limited to this, and at least one of them may be subjected to corona treatment. In other words, either one of the outer surface of the first sheet 21 and the inner surface of the third sheet 23 may be a corona-treated surface. Similarly, either one of the outer surface of the second sheet 22 and the inner surface of the fourth sheet 24 may be a corona-treated surface.

The notch portion 12 is provided, for example, on the opposite side of the turn-over starting portion 13 of the heat-bonded portion 11 . That is, in the packaging bag 100 according to the present embodiment, they are provided on the left and right sides of the upper portion of the heat-bonded portion 11 . The notch portion 12 is a V-shaped notch. Note that the shape of the notch portion 12 is not limited to the V-shape, and may be an I-shape, a U-shape, or a home plate shape. The packaging bag 100 is torn from the notch portion 12 and opened. That is, the notch portion 12 is an opening start portion. The notch portion 12 may be formed on all the sheets, or when the bag body 101 is opened after the exterior portion 102 is peeled off, the notch portion 12 may be formed only on the first sheet 21 and the second sheet 22. good.

Next, an apparatus and method for manufacturing the packaging bag 100 will be described with reference to the drawings. FIG. 4 is a schematic layout diagram of the packaging bag manufacturing apparatus 300. As shown in FIG. A packaging bag manufacturing apparatus 300 includes a first roll 31 , a second roll 32 , a third roll 33 , a fourth roll 34 , a table 35 , a cutter 36 , and a heat-sealing portion 37 .

In the packaging bag manufacturing apparatus 300, the third roll 33, the first roll 31, the second roll 32 and the fourth roll 34 are arranged in order from the top. The first roll 31 has a structure in which the first sheet 21 is wound around the shaft 311 . In the first roll 31, the first sheet 21 is wound around the shaft 311 so that the treated surface 211 faces outward. The first roll 31 pulls out the first sheet 21 from above the shaft 311 toward the table 35 .

The second roll 32 has a structure in which the second sheet 22 is wound around the shaft 321 . In the second roll 32, the second sheet 22 is wound around the shaft 321 so that the treated surface 221 faces inside. The second roll 32 is arranged below the first roll 31 , and the second sheet 22 is pulled out from above the shaft 321 toward the table 35 .

The third roll 33 has a structure in which the third sheet 23 is wound around a shaft 331 . In the third roll 33, the third sheet 23 is wound around the shaft 331 so that the treated surface 231 faces inside. The third roll 33 is arranged above the first roll 31 , and the third sheet 23 is pulled out from above the shaft 331 toward the table 35 .

The fourth roll 34 has a structure in which the fourth sheet 24 is wound around the shaft 341 . In the fourth roll 34, the fourth sheet 24 is wound around the shaft 341 so that the treated surface 241 faces outside. The fourth roll 34 is arranged below the second roll 32 , and the fourth sheet 24 is pulled out from above the shaft 341 toward the table 35 .

A sheet delivered from each roll is guided to a table 35 by rollers 301 . A fourth sheet 24, a second sheet 22, a first sheet 21 and a third sheet 23 are stacked on the table 35 in this order from bottom to top. Each sheet is placed on the table 35 so that the top and bottom surfaces are the same as when pulled from each roll.

That is, the upper surface of the first sheet 21 is the processing surface 211 , and the lower surface of the second sheet 22 is the processing surface 221 . Further, the third sheet 23 has a treated surface 231 on the lower surface, and the fourth sheet 24 has a treated surface 241 on the upper surface. As a result, the first sheet 21 and the second sheet 22 are arranged with their untreated surfaces, which have not been subjected to corona treatment, facing each other. The first sheet 21 and the third sheet 23, and the second sheet 22 and the fourth sheet 24 are arranged so that the treated surfaces face each other.

The cutter 36 cuts the first sheet 21 , the second sheet 22 , the third sheet 23 and the fourth sheet 24 . In the packaging bag manufacturing apparatus 300, after stacking four sheets, all the sheets are cut together. However, the configuration of the cutter 36 is not limited to this. For example, the configuration may be such that the sheet pulled out from each roll is individually cut. The cutter can widely adopt a configuration that can cut the sheet accurately and reliably.

A table 35 is a table for placing a sheet. The table 35 has positioning portions 351 that contact and position the sides of the first sheet 21, the second sheet 22, the third sheet 23, and the fourth sheet 24, for example. It should be noted that the positioning portion 351 may be omitted in the case where each sheet can be positioned by another method. When all the sheets are placed on the table 35 , the article Wh is placed between the first sheet 21 and the second sheet 22 .

The heat-bonded portion 37 heats and presses from the outside of the positioned sheets in the stacking direction, in other words, from the outside of the third sheet 23 and the fourth sheet 24 to form the heat-bonded portion 11 . A portion of the thermal welding portion 37 that presses the sheet from below is arranged on the table 35 , and a portion that presses the sheet from above is configured to be able to approach and separate from the table 35 .

In the packaging bag manufacturing apparatus 300 , the article Wh is arranged between the first sheet 21 and the second sheet 22 before being heat-sealed by the heat-sealing section 37 . In this state, the article Wh is hermetically sealed in the storage space 10 by heat-sealing the four sides. Then, in the packaging bag manufacturing apparatus 300 , the cutter 36 is used to form the notch portion 12 in the heat-bonded portion 11 .

In the packaging bag manufacturing apparatus 300, work is performed in a clean room so that foreign substances such as dirt, dust, and dust do not adhere to the articles Wh. Even when the prepared packaging bag 100 is taken out of the clean room, the articles Wh do not come into contact with the outside air. Therefore, it is possible to prevent foreign substances such as dirt, dust, and dust floating in the outside air from adhering to the articles Wh.

The articles Wh are housed in the housing space 10 of the packaging bag 100 and hermetically sealed in the clean room after manufacturing. The article Wh is used, for example, by being incorporated inside a device. Even the manufacturing process for incorporating the article Wh into the equipment is often carried out in a clean room in order to suppress adhesion of foreign matter.

Then, the packaging bag 100 containing the article Wh is taken out from the clean room used for manufacturing and transported to the clean room used for manufacturing the equipment. In other words, the outer surface of the exterior part 102 of the packaging bag 100 comes into contact with the outside air when being transported between different clean rooms. That is, foreign matter such as dirt, dust, and dirt adheres to the outer surface of the exterior portion 102 of the packaging bag 100 during transportation. Further, since the outer surfaces of the first sheet 21 and the second sheet 22 are covered with the third sheet 23 and the fourth sheet 24, adhesion of foreign matter such as dirt, dust, and dust is prevented. That is, the outer surfaces of the first sheet 21 and the second sheet 22 are not contaminated with foreign substances such as dirt, dust, dust, etc. In other words, they are in a clean state.

When the packaging bag 100 is carried into a clean room for manufacturing equipment, the exterior part 102, that is, the third sheet 23 and the fourth sheet 24 are peeled off. Since the packaging bag 100 has the opening part 13, the third sheet 23 and the fourth sheet 24 can be pinched. Then, the third sheet 23 and the fourth sheet 24 are pulled outward.

In the packaging bag 100, the second bonded portion 112 between the third sheet 23 and the first sheet 21 and the second bonded portion 112 between the fourth sheet 24 and the second sheet 22 are bonded to the first sheet 21 and the second sheet 22. bonding strength is weaker than that of the first bonding portion 111 of . Therefore, the third sheet 23 and the fourth sheet 24 can be easily peeled off from the bag body 101 without damaging the bag body 101, that is, without peeling off the first adhesive portion 111. In other words, in the packaging bag 100 , the exterior part 102 contaminated with dirt, dust, and foreign matter such as dust can be separated from the bag body 101 . Thereby, the first sheet 21 and the second sheet 22 whose outer surfaces are kept clean, that is, the bag body 101 can be exposed.

When the packaging bag 100 is used, the third sheet 23 and the fourth sheet 24 are peeled off immediately before carrying into a clean room for manufacturing equipment. As a result, only the bag body 101 formed of the first sheet 21 and the second sheet 22, which is not contaminated with foreign substances such as dust, dirt, dust, etc., can be carried into a clean room for manufacturing equipment. As a result, adhesion of foreign matter such as dirt, dust, and dust to the articles Wh can be suppressed, and entry of foreign matter into the clean room can also be suppressed. Then, in a clean room for manufacturing equipment, the bag body 101 is opened by tearing starting from the notch portion 12, and the article Wh accommodated inside the accommodation space 10 is taken out.

By using the packaging bag 100 described above, even when the article Wh manufactured in the clean room is taken out of the clean room to be transported to another clean room, foreign matter such as dirt, dust, dust, etc. can suppress the adhesion of In addition, entry of foreign matter such as dirt, dust, and dust into the clean room can be suppressed. In addition, in the packaging bag 100, the first sheet 21, the second sheet 22, the third sheet 23, and the fourth sheet 24 are made of polyolefin resin, so that they can be bonded by one heat bonding. . Therefore, recycling of the packaging bag 100 is easy. The manufacturing process of the sheet can be simplified as compared with the case of using a sheet formed by laminating a plurality of layers.

As described above, the packaging bag 100 is opened by tearing the bag body 101 after the third sheet 23 and the fourth sheet 24 have been peeled off. Therefore, the notch portion 12 may be formed only in the first sheet 21 and the second sheet 22 . However, in the packaging bag manufacturing apparatus 300 according to the present embodiment, the notch portion 12 is formed after manufacturing the packaging bag 100 . Therefore, notch portions 12 are formed in all of first sheet 21 , second sheet 22 , third sheet 23 and fourth sheet 24 .

Note that the packaging bag manufacturing apparatus 300 employs a method of manufacturing the packaging bag 100 by cutting the sheets with the cutter 36, arranging them, and thermally adhering them, but is not limited to this. For example, the cutter 36 may be used to cut after the four sides of the heat-bonded portion 11 are formed. When the cutter 36 cuts the stacked sheets, three sides are cut above the heat-bonded portion 11 . Also, the remaining one side is cut outside the heat-bonded portion 11 . By doing so, the turning start portion 13 can be formed.

By doing so, it is not necessary to position the table 35 accurately. Therefore, the configuration of the packaging bag manufacturing apparatus 300 can be simplified.

Further, when the laminated sheets are thermally bonded, three sides of the four thermally bonded portions 11 or two opposite sides are bonded, and the article Wh is attached to the bag body 101 via the non-bonded portions. You may arrange it. By doing so, since the article Wh is not arranged at the time of the initial thermal adhesion, it is possible to suppress the displacement of the sheet due to the arrangement of the article Wh. In addition, by leaving two opposing sides bonded, for example, a plurality of articles Wh can be accommodated in the bag body 101 from two directions. In this case, the turn-over starting portion 13 may be formed in the vicinity of the portion thermally bonded in advance, or may be formed in the vicinity of the portion thermally bonded later.

<Modification>
FIG. 5 is a schematic layout diagram of another example of the packaging bag manufacturing apparatus 300A. A packaging bag manufacturing apparatus 300A shown in FIG. 5 is different from the packaging bag manufacturing apparatus 300 in the direction in which the sheets of the first roll 31 and the fourth roll 34 are pulled out. Other points of the packaging bag manufacturing apparatus 300A are the same as the packaging bag manufacturing apparatus 300 of the packaging bag manufacturing apparatus 300A. Therefore, portions of the packaging bag manufacturing apparatus 300A that are substantially the same as those of the packaging bag manufacturing apparatus 300 are denoted by the same reference numerals, and detailed descriptions of the same portions are omitted.

As shown in FIG. 5 , the first roll 31 of the packaging bag manufacturing apparatus 300</b>A is arranged so that the first sheet 21 is pulled out from below the shaft 311 . Also, the fourth roll 34 is arranged so that the fourth sheet 24 is pulled out from below the shaft 341 .

That is, the third sheet 23 is wound around the third roll 33 so that the surface facing the first sheet 21 is the corona-treated surface 231 . The first sheet 21 is wound around the first roll 31 such that the surface facing the third sheet 23 is a corona-treated surface 211 . The second sheet 22 is wound around the second roll 32 such that the surface facing the fourth sheet 24 is a corona-treated surface 221 . The fourth sheet 24 is wound around the fourth roll 34 so that the surface facing the second sheet 22 is a corona-treated surface 241 .

By configuring in this way, it is possible to wind and form the sheet with the treated surface facing inward on all the rolls. For example, when the first sheet 21, the second sheet 22, the third sheet 23, and the fourth sheet 24 all have the same configuration, one type of roll can be used. As a result, the labor and time required to manufacture the packaging bag 100 can be reduced. In addition, it is possible to suppress the occurrence of defective products because it is less likely that the rolls will be attached incorrectly.

In this embodiment, the first sheet 21 of the first roll 31 is pulled out from below the shaft 311 and the fourth sheet 24 of the fourth roll 34 is pulled out from below the shaft 341 so that the surface to be processed is inside the rolls. pulled out.

However, it is not limited to this. The first sheet 21 of the first roll 31 is pulled out from above the shaft 311, the second sheet 22 of the second roll 32 is pulled out from below the shaft 321, and the third roll 33 The third sheet 23 of the roll 34 may be pulled out from below the shaft 331 and the fourth sheet 24 of the fourth roll 34 may be pulled out from above the shaft 341 . The direction in which the sheet is pulled out with respect to the shaft of each roll may be determined by the direction of the corona-treated surface of each sheet, or may be determined by the layout of the manufacturing apparatus.

<Example>
A specific example of the packaging bag according to the present invention will be described. As described above, the first sheet 21, the second sheet 22, the third sheet 23, and the fourth sheet 24 forming the packaging bag 100 are all made of polyolefin resin. The details of the resin forming the first sheet 21, the second sheet 22, the third sheet 23, and the fourth sheet 24 will be described.

The first sheet 21, the second sheet 22, the third sheet 23, and the fourth sheet 24 may all be made of polyethylene (PE) or polypropylene (PP).

Although the first sheet 21, the second sheet 22, the third sheet 23, and the fourth sheet 24 of the packaging bag 100 are made of the same material, they may have different heat resistance temperatures, in other words, different melting points. The packaging bag 100 is thermally bonded by applying heat and pressure from the outside in the stacking direction. Therefore, in the heat-bonded portion 11, the outside is hotter than the inside. For this reason, the third sheet 23 and the fourth sheet 24 arranged outside may have a higher heat resistance temperature than the first sheet 21 and the second sheet 22 arranged inside.

As such a configuration, for example, the first sheet 21 and the second sheet 22 are made of unstretched polypropylene (CPP), and the third sheet 23 and the fourth sheet 24, which are arranged on the outside, have a higher heat resistance than CPP. Oriented polypropylene (OPP) with a high T may also be used. By doing so, both the first bonding portion 111 and the second bonding portion 112 of the thermal bonding portion 11 can be firmly bonded together. As a method for changing the heat-resistant temperature, the difference in heat-resistant temperature depending on the presence or absence of stretching as described above may be used, or the difference in heat-resistant temperature depending on the grade may be used.

The thickness of the inner first sheet 21 and the second sheet 22 may be different from the thickness of the outer third sheet 23 and the fourth sheet 24 . For example, by making the thickness of the third sheet 23 and the fourth sheet 24 thicker than the thickness of the first sheet 21 and the second sheet 22, it is possible to prevent the packaging bag 100 from being damaged by an external member during transportation. . Moreover, by making the thickness of the first sheet 21 and the second sheet 22 thicker than the thickness of the third sheet 23 and the fourth sheet 24, it is possible to suppress the bag body 101 from being damaged by expansion due to the pressure difference.

When using the packaging bag manufacturing apparatus 300, the packaging bag 100 is a four-sided seal pouch. Note that the packaging bag 100 is not limited to a four-sided seal pouch. For example, when a packaging bag manufacturing apparatus is configured to manufacture by folding a sheet, it is also possible to make a three-sided seal pouch.

Although the embodiment of the present invention has been described above, the present invention is not limited to this content. Various modifications can be made to the embodiments of the present invention without departing from the spirit of the invention.

INDUSTRIAL APPLICABILITY The packaging bag of the present invention can be used as a bag for transporting articles such as semiconductor products, silicon wafers, magnetic disks, etc., which should not be mixed with foreign substances.

REFERENCE SIGNS LIST 100 packaging bag 101 bag main body 102 exterior portion 10 accommodation space 11 heat bonding portion 111 first bonding portion 112 second bonding portion 12 notch portion 13 turning start portion 21 first sheet 211 treated surface 212 inner surface 22 second sheet 221 treated surface 222 inner surface 23 third sheet 231 treated surface 24 fourth sheet 241 treated surface 300 manufacturing apparatus 300A manufacturing apparatus 301 roller 31 first roll 311 shaft 32 second roll 321 shaft 33 third roll 331 shaft 34 fourth roll 341 shaft 35 table 36 Cutter 351 Positioning part 37 Thermal welding part Wh Article

Claims (9)

A packaging bag in which the peripheral edges of four laminated sheets are thermally bonded,
a first sheet and a second sheet arranged to face each other;
a third sheet arranged outside the first sheet;
a fourth sheet arranged outside the second sheet;
The first sheet, the second sheet, the third sheet and the fourth sheet are formed of a polyolefin resin,
A packaging bag, wherein at least one of the facing surfaces of the first sheet and the third sheet and at least one of the facing surfaces of the second sheet and the fourth sheet are subjected to corona treatment. 2. The packaging bag according to claim 1, wherein both opposing surfaces of said first sheet and said third sheet and both opposing surfaces of said second sheet and said fourth sheet are corona-treated. 3. The packaging bag according to claim 1, which has an unbonded portion that is not thermally bonded outside the thermally bonded portion. 4. The packaging bag according to claim 3, wherein an unsealing start portion is provided at the heat-bonded portion of the first sheet and the second sheet. The packaging bag according to any one of claims 1 to 3, wherein the third sheet and the fourth sheet have a higher heat resistance temperature than the first sheet and the second sheet. The packaging bag according to any one of claims 1 to 5, wherein the first sheet, the second sheet, the third sheet and the fourth sheet are all made of polyethylene. The packaging bag according to any one of claims 1 to 5, wherein the first sheet, the second sheet, the third sheet and the fourth sheet are all made of polypropylene. The first sheet and the second sheet are formed of unstretched polypropylene,
8. The packaging bag according to claim 7, wherein said third sheet and said fourth sheet are made of oriented polypropylene. a first sheet and a second sheet facing each other, a third sheet disposed outside the first sheet, and a fourth sheet disposed outside the second sheet; A packaging bag manufacturing apparatus for thermally bonding the peripheral edges of four sheets,
a first roll around which the first sheet is wound;
a second roll around which the second sheet is wound;
a third roll around which the third sheet is wound;
a fourth roll around which the fourth sheet is wound;
a heat welding unit that simultaneously heats and presses the peripheral edges of the four sheets that are pulled out from each of the rolls and stacked,
The third roll, the first roll, the second roll and the fourth roll are arranged in this order,
The third sheet is wound around the third roll so that the surface facing the first sheet is a corona-treated surface,
The first sheet is wound around the first roll so that the surface facing the third sheet is a corona-treated surface,
The second sheet is wound around the second roll so that the surface facing the fourth sheet is a corona-treated surface,
The apparatus for manufacturing a packaging bag, wherein the fourth sheet is wound around the fourth roll so that the surface facing the second sheet is corona-treated.

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