JP6811917B2 - Resin packaging bag - Google Patents

Description

The present invention relates to a resin packaging bag, and more particularly to a resin packaging bag having a top opening, left and right gussets, and a seal bottom sealed or sealed by a heat seal wire. is there.

Resin-made gusseted packaging bags used for packaging food in food departments of large-scale commercial facilities and food retail stores are widely used in practical use. This type of bag is not limited to food packaging applications, but also transiently stores household garbage, used paper diapers, garbage bags for disposing of pet feces, or water-soaked clothing and articles. It is used for multiple purposes, such as a storage bag for storing food.

In such a resin packaging bag, a continuous tube-shaped resin film manufactured by an inflation method or the like or a laminated continuous sheet-shaped resin film is heat-sealed by a heat-sealing device and cut into a single bag size. Manufactured by

As the heat sealing device, an elevating type heat sealing device that is intermittently operated and a rotary heat sealing device that is continuously operated are known. As described in Japanese Patent Application Laid-Open No. 2003-33981, the elevating heat-sealing device includes a movable sealer that moves up and down intermittently, and the movable sealer descends onto a resin film in a stationary state to form a resin. The bottom of the film is locally heated and melted to fuse and form the linear bottom seal of the bag. As described in JP-A-2008-56261, JP-A-2008-265812, etc., the rotary heat-sealing device is provided with a rotary roll equipped with a heat-sealing bar, and is used for a resin film that is continuously conveyed. It is configured to bring the heat seal bar on the rotating roll into contact. The ridge of the heat seal bar that extends linearly in the direction of the axis of the rotating roll locally heats and melts the bottom part of the resin film, and puts a linear seal parallel to the rotation center axis of the rotating roll on the bottom part of the bag. Fuse and form.

FIG. 11A is a perspective view showing the configuration of a conventional resin packaging bag manufactured by such a heat sealing device. 11 (B) and 11 (C) are a plan view and a bottom view schematically showing the shape or outline of the top opening and the bottom of the resin packaging bag shown in FIG. 11 (A).

The resin packaging bag 1 made of a resin film has a top opening 2, a seal bottom 3, and a gusset portion 4. A straight linear welded portion or fused portion 6 (hereinafter referred to as "linear fused portion 6") extending over the entire width W of the bag 1 is formed on the seal bottom portion 3 by a heat sealing device (not shown). Will be done. Since the resin packaging bag 1 has a four-layer structure in the gusset portion 4 (width W1) and a two-layer structure in the central band 8 (width W2) between the gusset portions 4, the linear fused portion 6 has a four-layer structure. The four layers of film are fused in the gusset portions 4 (width W1) on both sides, and the two layers of film are fused in the central band 8 (width W2). That is, the linear fusion portion 6 changes from the fusion of the four-layer film to the fusion of the two-layer film at the intersection portion K between the inner folded edge 5 and the linear fusion portion 6. In such a linear fused portion 6, the seal is likely to be damaged at the intersection portion K where the number of film layers changes. This is due to the fact that the external force acting on the bag 1 due to the opening / closing operation of the bag 1 and the load or pressure of the contents act intensively on the intersection portion K as shown by the arrows N and M. It is considered that this is because the fusion of the intersection portion K tends to be incomplete due to the change in the number of film layers, and therefore the intersection portion K tends to be weakened.

Therefore, the present inventors have tried to manufacture the bag so that the inner folded edges 5 of the left and right gusset portions 4 are arranged substantially on the center line of the bag and the left and right inner folded edges 5 are in contact with each other. Since the bag having such a structure has substantially no central band 8 (two-layer film portion), a linear seal for fusing the four-layer film is formed over the entire width of the bag. However, in a bag provided with such a linear fused portion 6, fusion is likely to be insufficient at a portion where the inner folded edges 5 are in contact with each other, that is, at the position of the center line of the bag. Therefore, the center of the linear seal is formed. The part is easily damaged.

FIG. 12A is a perspective view showing the configuration of a conventional resin packaging bag intended to prevent damage to the seal at the intersection portion K. 12 (B) and 12 (C) are a plan view and a bottom view schematically showing a top opening and a bottom of the resin packaging bag shown in FIG. 12 (A).

FIG. 12 shows a resin packaging bag 1 having a structure in which a concave or U-shaped deformed portion 7 protruding downward is formed at an intersection portion K. The deformed portion 7 functions to relieve stress concentration at the intersection portion K and prevent damage to the linear fused portions 6 (6a, 6b, 6c) at the intersection portion K. A resin packaging bag having this seal structure is described in Registered Utility Model No. 3072321 (Patent Document 4).

FIG. 13A is a perspective view showing a resin packaging bag having another configuration intended to prevent damage to the seal at the intersection portion K. 13 (B) and 13 (C) are a plan view and a bottom view schematically showing a top opening and a bottom of the resin packaging bag shown in FIG. 13 (A).

FIG. 13 shows a resin packaging bag 1 in which the only deformed portion 7 is formed in the central portion of the linear fused portion 6. The deformed portion 7 is curved so as to bulge downward from the straight portion of the linear fused portion 6. The intersection portion K between the inner folded edge 5 and the linear fused portion 6 is located at the curved portion of the deformed portion 7. A resin packaging bag having this seal structure is described in Japanese Patent No. 5400746 (Patent Document 5) and Japanese Patent No. 5567705 (Patent Document 6) according to the application of the applicant.

Japanese Unexamined Patent Publication No. 2003-33981 Japanese Unexamined Patent Publication No. 2008-56261 Japanese Unexamined Patent Publication No. 2008-265812 Registered Utility Model No. 3072321 Japanese Patent No. 5400746 Japanese Patent No. 5567705

However, as shown in Registered Utility Model No. 3072321 (Patent Document 4), when a plurality of deformed portions 7 (FIG. 12) separated in the width direction of the bag 1 are formed in the linear fused portion 6 (FIG. 12). The heat seal bar must be brought into contact with the resin film portions forming the respective deformed portions 7 at a uniform pressure, and the resin films of the left and right deformed portions 7 must be heated at a uniform temperature. However, it is relatively difficult to heat the resin films of the separated deformed portions 7 at a uniform pressure and a uniform temperature.

On the other hand, as described in Japanese Patent No. 5400746 (Patent Document 5) and Japanese Patent No. 5567705 (Patent Document 6), the only deformed portion 7 (FIG. 13) is provided in the central portion in the linear fusion portion 6 (Patent Document 6). According to the seal structure formed in FIG. 13), such a manufacturing problem can be solved. However, the seal structure of this form has a relatively large gusset size (width W1) as shown in FIG. 13, and therefore a bag having a relatively small width size (width W2) in the central band 8 (two-layer film portion). Is applicable, but it cannot be applied to a bag in which the gusset size (width W1) is relatively small and therefore the width W2 of the central band 8 is set relatively large.

The present invention has been made in view of such circumstances, and an object of the present invention is a resin in which the gusset size (W1) is set relatively small and the width of the central band (W2) is set relatively large. In the packaging bag, prevent damage to the film welded part at the part (K) where the number of film layers changes, and prevent excessive load from being applied to the film welded part when opening and closing the bag and storing the contents. It is in.

The present invention is manufactured by heat-sealing (heat welding) and cutting a continuous tubular resin film (semi-transparent polyethylene film, etc.) manufactured by the inflation method in order to achieve the above object, and is manufactured by opening the top (2). ), Left and right gussets (4), and a front-view rectangular contour resin packaging bag (1) having a seal bottom (3) sealed or sealed by a heat seal wire, and has a total width (W). Is 100 to 300 mm, the total height (H) is 250 to 450 mm, the width of the gusset (W1) is 10 to 50 mm, and the width of the central band (W2) is set to 0.6 to 0.9 x total width (W). In the resin packaging bag (1)
The heat seal wire consists of an arcuate fused portion (10) that is generally curved so as to bulge toward the bottom edge (1a) of the bag and extends over the entire width (W) of the bag.
The arcuate fusion portion has an arcuate shape centered on the center of curvature located above the top opening.
The central portion (α) of the arcuate fused portion closest to the bottom edge is positioned at a position separated by a dimension (H1) of 5 mm or more and 15 mm or less from the bottom edge, and is positioned at the side edge (1b) of the bag. The side end portion (β) of the arcuate fused portion that is located and is the farthest from the bottom edge is positioned at a position separated from the bottom edge by a dimension (H2) of 10 mm or more and 25 mm or less, and is relative to the bottom edge. The dimensional difference (ΔH) of each separation distance between the central portion and the side end portion is set to a dimension of 3 mm or more and 20 mm or less.
Provided is a resin packaging bag characterized in that the intersection angle (θ') between the inner folded edge (5) of the gusset portion and the arc-shaped fused portion is set within the range of 80 to 87 degrees. To do.

Preferably, the arcuate fused portion extends symmetrically with respect to the bag central axis (CL), the tangent of the arc-shaped (gamma) is arcuate fused portion positioned on the center axis of the bag of the bottom (alpha) is parallel to the bag bottom (1a), said arcuate normal (eta) coincides with the central axis of the bag at the bottom of the arc-shaped fused portion.

According to the above configuration of the present invention, the heat seal wire is curved in an arc shape so as to bulge toward the bottom edge side, so that when the bag is filled with a fluid or fluid, the shape is close to a sphere. As a result of the swelling, the load or pressure of the contents of the bag or the internal fluid is dispersed, and the load or pressure acts on the entire heat seal wire relatively evenly or uniformly. According to the bag breaking strength test of the present inventors, the resin packaging bag in which the heat seal wire is curved in this way is 1.5 times or more as much as the resin packaging bag having a straight straight heat seal wire. Demonstrate the bag breaking strength of. This reduces the stress acting on the film welded part in the part (K) where the number of film layers changes due to the dispersion, homogenization or equalization of the load or pressure acting on the heat seal wire, or this part ( It is considered that this is because the stress concentration of K) could be avoided.

Preferably, the width W1 of the gusset portion is set in the range of 0.025 to 0.125 × W, and the width W2 of the central band is set in the range of 75 to 250 mm.

The present invention is also a resin packaging bag manufacturing apparatus for manufacturing a resin packaging bag having the above configuration.
A heat seal roll (11) and a film bearing roll (12) that rotate synchronously around the parallel rotation center axis (X, Y),
It has a running path (15) of a resin film formed between the heat seal roll and the film bearing roll.
A heat seal bar (20) is attached to the outer peripheral portion of the heat seal roll, and the heat seal bar has an arcuate ridge (21) that is pressed against the resin film during rotation. , Has a contour that matches the arc-shaped fusion splicer (10), and is covered with a heat-resistant mold release sheet that constitutes a heat flow suppressing material or a heat flow adjusting material.
The film bearing roll provides a resin packaging bag manufacturing apparatus characterized by having a heat-resistant resin coating layer (14) that is elastically deformable.

The present invention is further a method for manufacturing a resin packaging bag for manufacturing a resin packaging bag having the above configuration.
The heat seal roll (11) and the film bearing roll (12) of the rotary heat seal device that rotates synchronously around the parallel rotation center axis (X, Y) are arranged in parallel, and the arcuate fusion portion (10) An arcuate ridge (21) having a contour corresponding to the above is provided on the heat seal bar (20) of the heat seal roll.
The ridge was covered with a heat-resistant mold release sheet constituting a heat flow suppressing material or a heat flow adjusting material, and the outer peripheral surface of the film bearing roll was covered with a heat-resistant resin coating layer (14) that was elastically deformable. Using a heat seal device,
A flat tube (T) of the resin film forming the gusset for the gusset (4) is passed through the resin film running path (15) between the heat seal roll and the film bearing roll.
Made of a resin characterized by synchronously rotating the heat seal roll and the film support roll, pressing the ridge against the flat tube, heating and pressurizing the flat tube, and heat welding the resin film. Provided is a method for manufacturing a packaging bag.

According to the manufacturing apparatus and manufacturing method having such a configuration, the resin packaging bag can be continuously manufactured, and the productivity of the resin packaging bag can be improved. Further, according to the manufacturing apparatus and manufacturing method according to the present invention, the number of film layers is suppressed or adjusted by a heat-resistant mold release sheet to suppress or adjust the heat flow generated at the time of heat transfer contact between the ridge and the resin film. It is possible to surely prevent the occurrence of pinholes and the like in the portion (K) where the value changes.

According to the resin packaging bag of the present invention, in the resin packaging bag in which the gusset size (W1) is set relatively small and the width of the central band (W2) is set relatively large, the portion where the number of film layers changes ( In addition to preventing damage to the film welded portion in K), it is possible to prevent an excessive load from being applied to the film welded portion when opening and closing the bag and when storing the contents, and the strength of the broken bag can be relatively greatly increased.

Further, according to the resin packaging bag manufacturing apparatus and manufacturing method according to the present invention, such a resin packaging bag can be continuously manufactured, and the productivity of the resin packaging bag can be improved. It is possible to reliably prevent the occurrence of pinholes or the like in the portion (K) where the number of film layers changes.

FIG. 1 (A) is a perspective view of a resin packaging bag according to a preferred embodiment of the present invention, and FIGS. 1 (B) and 1 (C) show a top opening and a bottom of the resin packaging bag. Alternatively, it is a plan view and a bottom view which roughly show the outline. FIG. 2 is a front view of the resin packaging bag shown in FIG. FIG. 3 is a side view of the resin packaging bag shown in FIG. FIG. 4 (A) is an enlarged plan view of the resin packaging bag, and FIG. 4 (B) is an enlarged front view of the bottom region of the resin packaging bag. 5 (A) is a cross-sectional view taken along the line AA of FIG. 2, and FIG. 5 (B) is an enlarged view of a portion BB'of FIG. 5 (A). FIG. 6 is a plan view showing a state in which the top opening of the resin packaging bag is widened. FIG. 7 is a vertical sectional view and a partially enlarged sectional view showing the configuration of the rotary heat sealing device. FIG. 8 is a vertical sectional view and a partially enlarged sectional view showing the configuration of the heat seal bar. FIG. 9 is a front view of the heat seal bar shown in FIG. 10 (A) and 10 (B) are conceptual perspective views and vertical cross-sectional views for explaining a test method for a bag breaking strength test of a resin packaging bag. FIG. 11 (A) is a perspective view showing the configuration of a conventional resin packaging bag provided with a linear linear fusion zone extending straight, and FIGS. 11 (B) and 11 (C) are FIGS. 11 (C). It is a top view and the bottom view which roughly show the form or outline of the top opening and the bottom part of the resin packaging bag shown in (A). 12 (A) is a perspective view showing the configuration of a conventional resin packaging bag in which a pair of left and right deformed portions are formed in a linear linear fused portion, and FIGS. 12 (B) and 12 (C) are views. 12 is a plan view and a bottom view schematically showing a top opening and a bottom of the resin packaging bag shown in FIG. 12A. 13 (A) is a perspective view showing the configuration of a conventional resin packaging bag in which a single deformed portion is formed in the central portion of a linear linear fused portion, and FIGS. 13 (B) and 13 (C). ) Is a plan view and a bottom view schematically showing the top opening and the bottom of the resin packaging bag shown in FIG. 13 (A).

Hereinafter, the resin packaging bag according to the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1A is a perspective view of a resin packaging bag according to a preferred embodiment of the present invention. 1B and 1C are a plan view and a bottom view schematically showing the shape or outline of the top opening and the bottom of the resin packaging bag. 2 and 3 are a front view and a side view of the resin packaging bag shown in FIG. FIG. 4A is a plan view of the resin packaging bag, and FIG. 4B is an enlarged front view of the bottom region of the resin packaging bag. 5 (A) is a cross-sectional view taken along the line AA of FIG. 2, and FIG. 5 (B) is an enlarged view of a portion BB'of FIG. 5 (A). FIG. 6 is a plan view showing a state in which the top opening of the resin packaging bag is widened.

The resin packaging bag 1 is made of a resin film such as a translucent polyethylene film, and has a top opening 2, a seal bottom 3, and a gusset portion 4. On the bottom 3 of the seal, an arc-shaped heat-welded portion or a fused portion 10 (hereinafter, referred to as “arc-shaped fused portion 10”) extending over the entire width W of the bag 1 is provided as a heat sealing device (FIGS. 7 to 7 to 7). It is formed by FIG. 9). The resin packaging bag 1 has a four-layer structure in the left and right gusset portions 4 (width W1), and has a two-layer structure in the central band 8 (width W2) between the gusset portions 4. The width W1 of the gusset portion 4 is considerably smaller than the width W2 of the central band 8, and therefore the inner folded edges 5 of the left and right gusset portions 4 are relatively far apart from each other. Since the dimension W1 of the gusset portion 4 is much smaller than that of the resin packaging bag (FIG. 13), the top opening 2 has a relatively small width or depth dimension as shown in FIGS. 1B and 6. It can only extend to a flat contour opening.

In the present embodiment, the total width W of the resin packaging bag 1 (hereinafter referred to as “bag 1”) is in the range of 100 to 300 mm (for example, 210 mm), and the width W2 of the central band 8 is 75 to 250 mm (hereinafter referred to as “bag 1”). For example, it is set in the range of 160 mm) or 0.6 to 0.9 × W (for example, 0.75 × W), and the width W1 of the gusset portion 4 is 10 to 50 mm (for example, 25 mm) or It is set in the range of 0.05 to 0.125 × W (for example, 0.11 × W). Further, the total height H (FIG. 2) of the bag 1 is set in the range of 250 to 450 mm (for example, 330 mm). For example, the dimensions of each part of the bag 1 are set to the total width W = 210 mm, W2 = 25 mm, W1 = 160 mm, and H = 330 mm.

As shown in FIG. 2, the arcuate fused portion 10 formed on the bottom portion 3 of the seal extends over the entire width of the bag 1 and is curved so as to bulge downward as a whole. The arcuate fused portion 10 is curved with a predetermined radius of curvature about a center of curvature (not shown) located on the center line CL of the bag in the upper region of the top opening 2.

As shown in FIG. 4 (B), the arcuate fused portion 10 extends symmetrically with respect to the center line CL of the bag. The lowermost center α of the arc-shaped fused portion 10 is located on the center line CL and is separated from the bottom edge 1a of the bag 1 by the dimension H1. The tangent line γ of the arcuate fused portion 10 at the lowermost center α is parallel to the lower edge 1a. The normal line η of the arcuate fused portion 10 at the lowermost center α coincides with the center line CL.

The uppermost side end β of the arcuate fused portion 10 located on the side edge 1b of the bag 1 is separated from the lower edge 1a by the dimension H2. The arcuate fused portion 10 intersects the inner folded edge 5 at the intersection portion K. The inclination angle θ of the arc-shaped fused portion 10 at the intersection portion K corresponds to the curvature of the arc-shaped fused portion 10. The inclination angle θ is set to an angle in the range of 3 to 15 degrees (preferably 3 to 10 degrees), for example, 4 degrees or 5 degrees, and the intersection angle θ between the inner folded edge 5 and the arcuate fusion portion is θ. 'Is set to an angle in the range of 75-87 degrees (preferably 80-87 degrees), for example 85 degrees or 86 degrees. In the present embodiment, the dimension H1 is set in the range of 5 to 15 mm (for example, 12 mm), and the dimension H2 is set in the range of 10 to 25 mm (for example, 20 mm). The difference ΔH (= H2-H1) between the dimensions H1 and H2 is set to 3 to 20 mm, for example, 8 mm.

7A and 7B are a vertical sectional view and a partially enlarged sectional view showing a configuration of a rotary heat sealing device, and FIGS. 8 and 9 are a vertical sectional view, a partially enlarged front view and a front view of the heat sealing bar.

The bag 1 having the above configuration can be continuously manufactured by using a rotary heat sealing device. As shown in FIG. 7, the heat seal device is composed of a heat seal roll 11 arranged on the upper side and a film bearing roll 12 arranged on the lower side. The heat seal roll 11 is rotationally driven in the rotation direction Q about the rotation center axis X. The film bearing roll 12 is rotationally driven in the rotation direction Q'around the rotation center axis Y parallel to the rotation center axis X of the heat seal roll 11. A resin film flat tube T with a gusset manufactured by an inflation method or the like runs on the film bearing roll 12 in the arrow V direction in the traveling path 15 between the heat seal roll 11 and the film bearing roll 12.

The heat seal roll 11 incorporates a heat source for heat seal (not shown). A pair of heat seal bars 20 are mounted on the outer peripheral portion of the heat seal roll 11. The heat seal bars 20 are symmetrically arranged with an angular interval of 180 degrees. The film bearing roll 12 has a structure in which the outer peripheral surface of the roll body 13 is coated with an elastic heat-resistant resin coating layer 14. The heat seal roll 11 and the film bearing roll 12 rotate synchronously in a direction corresponding to the traveling direction (arrow V direction) of the flat tube T.

The arcuate ridge portion 21 shown in FIGS. 8 and 9 is projected from the tip surface 23 of the heat seal bar 20. The heat seal bar 20 extends parallel to the rotation center axis X of the heat seal roll 11. As shown in FIG. 9, the ridge portion 21 on the heat seal bar 20 has a contour or shape corresponding to the arcuate fusion portion 10. In the partially enlarged view of FIG. 8, the center line CL'of the ridge portion 21 is shown. The center line CL'is orthogonal to the rotation center axis X. The ridge portion 21 has a cross-sectional shape that is symmetrical in the front-rear direction in the tangential direction of the rotation direction Q with respect to the center line CL', and the tip portion of the ridge portion 21 has a front-rear curved portion 22 having a predetermined radius of curvature. Has an overall curved contour. The tip surface between the curved portions 22 is formed on a flat or gently curved surface. The width W3 of the tip portion of the ridge portion 21 is set within the range of 1 to 3 mm.

A heat-resistant mold release sheet 30 (hereinafter, referred to as “sheet 30”) constituting a heat flow suppressing material or a heat flow adjusting material is attached to the projecting portion 21. The sheet 30 is, for example, a sheet material having a thickness of about 0.1 mm and made of a glass cloth impregnated with a fluororesin. The sheet 30 is attached to the ridge portion 21 by a mounting bracket or the like (not shown) and covers the ridge portion 21.

At the time of manufacturing the bag 1, the flat tube T having the gusset (folded) formed for the gusset portion 4 travels in the traveling path 15 between the heat seal roll 11 and the film bearing roll 12 in the arrow direction V. The heat seal roll 11 and the film bearing roll 12 rotate in the Q and Q'directions, respectively. As shown enlarged in FIG. 7, the ridge portion 21 of the heat seal bar 20 is pressed against the flat tube, and the flat tube T is heated and pressurized to heat-weld the resin film. While the ridge portion 21 is pressed against the flat tube, the heat-resistant resin coating layer 14 of the film bearing roll 12 is elastically deformed, so that the resin film is uniformly subjected to an appropriate pressure from the ridge portion 21. It is heated by.

An arcuate fused portion 10 extending over the entire width of the flat tube T is formed in the flat tube T that has passed through the nip region (running path 15) between the heat seal roll 11 and the film bearing roll 12. The flat tube T is cut to the length dimension of the bag 1 by a cutting device (not shown), and thus the bag 1 shown in FIGS. 1 to 6 is manufactured.

The present inventors have formed a bag 1 (Example) manufactured in this manner and a bag 1 (Comparative Example) in which a linear fused portion 6 (FIG. 11) extending straight over the entire width W of the bag is formed. Was manufactured, and a bag breaking strength test was carried out to compare the strengths of both. The only difference between the bags 1 of the examples and the comparative examples is that the bag 1 of the examples has an arcuate fusion section 10 and the bag 1 of the comparative example has a linear linear fusion section 6. Both were manufactured under exactly the same materials, dimensions and conditions, except in this respect. The widths W1, W2, and W3 of the bags 1 of Examples and Comparative Examples were set to about 210 mm, about 160 mm, and about 25 mm, and the height H was set to about 330 mm. The dimensions H1 and H2 of the arc-shaped fused portion 10 were set to about 13 mm and about 19 mm, and the dimensional difference ΔH was set to about 6 mm.

10 (A) and 10 (B) are conceptual perspective views and vertical cross-sectional views for explaining a test method for a bag breaking strength test.

FIG. 10 shows the bag 1 according to the embodiment. The present inventors fill the inner region 1c of the bag 1 with air (atmosphere), close the top opening 2 with a binding tool such as a string or a rubber band or a tightening tool 40, and then inflate into a tense state with the sealed air. The bag 1 was pressed by the loading surface λ from above and below with a load F, the load F was gradually increased, and the load F at the time when the arcuate fusion portion 10 was damaged was measured as the bag breaking load. FIG. 10 shows the bag 1 of the present embodiment having the arc-shaped fusion section 10, but the present inventors have shown the bag 1 of the comparative example provided with the linear linear fusion section 6 (FIG. 10). The same test was carried out for 11), and the crushing load (load F) was measured by the same test method.

In this bag breaking strength test, in the bag 1 (FIG. 11) of the comparative example provided with the linear linear fusion section 6, the bag breaking load was only about 4 kg, whereas the arc-shaped fusion was performed. In the bag 1 of the present embodiment provided with the part 10, the bag breaking load was about 7 kg. Therefore, it has been found that the bag breaking strength of the bag 1 can be significantly increased by adopting the arc-shaped fused portion 10.

Further, the present inventor manufactured the bags 1 of the above-described example and the comparative example with the sheet 30 removed from the ridge portion 21, and carried out the same bag-breaking strength test. The bag 1 of the example weighed about 7 kg, and the bag 1 of the comparative example weighed about 4 kg. Therefore, it is considered that the increase in the bag breaking strength is not directly related to the presence or absence of the sheet 30 but is due to the difference in the form of the heat seal wire.

On the other hand, if the bag 1 of the above embodiment is manufactured with the sheet 30 removed from the ridge portion 21, pinholes are likely to occur at the intersection portion K, and the sheet 30 is attached to the ridge portion 21 to generate pinholes. It was found that the problem was solved by performing heat sealing. Therefore, when the arc-shaped fused portion 10 is formed in the bag 1, it is desirable to perform heat sealing with the sheet 30 attached to the ridge portion 21.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various modifications or modifications can be made within the scope of the present invention described in the claims. It goes without saying that it is possible.

For example, the radius of curvature of the arc-shaped fused portion 10, the dimensions of each portion, the dimensions of each portion of the ridge portion 21, the shape of each portion, and the like can be appropriately redesigned according to the dimensions and shape of the bag 1.

The present invention has a top opening, left and right gussets, and a seal bottom sealed or sealed by a heat seal wire, the gusset size (W1) is set relatively small, and the width of the central band (W2). Is preferably applied to a resin packaging bag in which the value is set relatively large. According to the present invention, it is possible to prevent the film welded portion from being damaged in the portion (K) where the number of film layers changes, and to prevent an excessive load from being applied to the film welded portion when opening and closing the bag or storing the contents. However, this is extremely advantageous in practical use because the bag breaking strength can be increased relatively remarkably.

Further, the present invention is applied to a resin packaging bag manufacturing apparatus and a manufacturing method for continuously manufacturing such a resin packaging bag. According to the present invention, the productivity of the resin packaging bag can be improved, and pinholes and the like can be reliably prevented from occurring in the portion (K) where the number of film layers changes.

1 Resin packaging bag
1a Bottom edge 1b Side edge 1c Internal area of bag 2 Top opening
3 Seal bottom
4 gusset part
5 Inner folded edge
8 Central band 10 Arc-shaped fusion part (arc-shaped heat welding part or fusion part)
11 Heat seal roll 12 Film support roll 15 Runway 20 Heat seal bar 21 Protruding part 30 Heat-resistant mold release sheet α Center bottom β Top side end γ Tangent η Normal θ Inclined angle λ Loading surface CL, CL' Center line H Overall height H1, H2 Height dimension ΔH Height dimension difference K Intersection part T Resin film flat tube with gusset W Overall width of bag W1, W2, W3 Width X, Y Rotation center axis

Claims (6)

Manufactured by heat-sealing and cutting a continuous tubular resin film produced by the inflation method, it was sealed or sealed by a top opening (2), left and right gussets (4), and a heat-sealing wire. A resin packaging bag (1) having a front view rectangular contour having a seal bottom (3), having an overall width (W) of 100 to 300 mm , an overall height (H) of 250 to 450 mm, and a gusset portion width (W1). In the resin packaging bag (1) in which the width (W2) of the central band is set to 0.6 to 0.9 × the total width (W) of 10 to 50 mm , respectively.
The heat seal wire consists of an arcuate fused portion (10) that is generally curved so as to bulge toward the bottom edge (1a) of the bag and extends over the entire width (W) of the bag.
The arcuate fusion portion has an arcuate shape centered on the center of curvature located above the top opening.
The central portion (α) of the arcuate fused portion closest to the bottom edge is positioned at a position separated by a dimension (H1) of 5 mm or more and 15 mm or less from the bottom edge, and is positioned at the side edge (1b) of the bag. The side end portion (β) of the arcuate fusion portion located and farthest from the bottom edge is positioned at a position separated from the bottom edge by a dimension (H2) of 10 mm or more and 25 mm or less, and is relative to the bottom edge. The dimensional difference (ΔH) of each separation distance between the central portion and the side end portion is set to a dimension of 3 mm or more and 20 mm or less.
A resin packaging bag characterized in that the intersection angle (θ') between the inner folded edge (5) of the gusset portion and the arc-shaped fused portion is set within the range of 80 to 87 degrees . The arc-shaped fusion portion extends symmetrically with respect to the central axis (CL) of the bag, and the arc-shaped tangent line (γ) is the lowermost portion of the arc-shaped fusion portion located on the central axis of the bag. The first aspect of claim 1 , wherein the arc-shaped normal line (η) is parallel to the bottom edge (1a) of the bag at (α) and coincides with the central axis of the bag at the lowermost portion. Resin packaging bag. The resin packaging bag according to claim 1 or 2, wherein the width (W1) of the gusset portion is set to 0.025 to 0.125 × total width (W) . The resin packaging bag according to any one of claims 1 to 3, wherein the resin packaging bag has a central band width (W2) set to 75 to 250 mm . A device for manufacturing a resin packaging bag for manufacturing the resin packaging bag according to any one of claims 1 to 4 .
A heat seal roll (11) and a film bearing roll (12) that rotate synchronously around the parallel rotation center axis (X, Y),
It has a running path (15) of a resin film formed between the heat seal roll and the film bearing roll.
A heat seal bar (20) is attached to the outer peripheral portion of the heat seal roll, and the heat seal bar has an arcuate ridge (21) that is pressed against the resin film during rotation. , Has a contour that matches the arc-shaped fusion splicer (10), and is covered with a heat-resistant mold release sheet that constitutes a heat flow suppressing material or a heat flow adjusting material.
The film bearing roll is a resin packaging bag manufacturing apparatus characterized by having a heat-resistant resin coating layer (14) that is elastically deformable. A method for manufacturing a resin packaging bag for manufacturing the resin packaging bag according to any one of claims 1 to 4 .
The heat seal roll (11) and the film bearing roll (12) of the rotary heat seal device that rotates synchronously around the parallel rotation center axis (X, Y) are arranged in parallel, and the arcuate fusion portion (10) An arcuate ridge (21) having a contour matching the above is provided on the heat seal bar (20) of the heat seal roll.
The ridge was covered with a heat-resistant mold release sheet constituting a heat flow suppressing material or a heat flow adjusting material, and the outer peripheral surface of the film bearing roll was covered with an elastically deformable heat-resistant resin coating layer (14). Using a heat seal device,
A flat tube (T) of the resin film forming the gusset for the gusset (4) is passed through the resin film running path (15) between the heat seal roll and the film bearing roll.
Made of a resin characterized by synchronously rotating the heat seal roll and the film support roll, pressing the ridge against the flat tube, heating and pressurizing the flat tube, and heat welding the resin film. How to make a packaging bag.

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