JP2000318748A - Air-permeable bag and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily degas from a slit by providing an air-permeable bag formed with the slit between opposite plastic films at a non-heat-sealed portion of dotted heat-sealed portions. SOLUTION: A square-shaped heat-sealable plastic film 11 and a plastic film 12 are overlaid, and both side ends are glued at side end heat-sealed portions to provide a cylinder. Dotted heat-sealed portions comprising heat-sealed portions 3a and a non-heat-sealed portions 3b are provided for gluing in parallel to an opening end in the vicinity of the opening end on a lower side of the cylinder, and slits 4 are formed between the films 11, 12 at the non-heat sealed portions 3b on the dotted heat-sealed portions. Air sealed in a bag when filling contents is degassed mainly from the slits 4 formed between the films 11, 12 on the non-heat-sealed portions 3b of the dotted heat-sealed portions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a breathable bag which can be used as a rice bag or the like and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, in a gas-permeable rice bag or the like made of a plastic film, a dashed heat-bonded portion consisting of a heat-bonded portion and a non-heat-bonded portion is formed in the vicinity of two opposing sides to provide air permeability. In general, the configuration is such that the components are made to be in contact with each other. However, in the case of the air-permeable bag having this configuration, if the length of the non-heat-bonded portion of the dashed-shaped heat-bonded portion is reduced, the air permeability becomes worse. The disadvantage is that the content leaks out of the non-heat-bonded area, which makes it difficult to quickly deaerate the air enclosed inside the bag when filling with rice or other content. was there.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a breathable bag which has good air permeability and does not leak contents, and a method for producing the same.

[0004]

Means for Solving the Problems In the vicinity of one opening end of a cylindrical body made of a plastic film having thermal bonding properties, a broken line-shaped thermal bonding portion comprising a thermal bonding portion and a non-thermal bonding portion parallel to the opening end. Is formed in the air-permeable bag having a configuration in which a gap is formed between the opposing plastic films in the non-heat-bonded portion of the dashed heat-bonded portion, thereby reducing the length of the non-heat-bonded portion. Even so, since a gap is formed between the opposing plastic films in the non-thermally bonded portion, the air can be easily degassed from the gap and the contents do not leak.

[0005] In the above-mentioned breathable bag, the gap is formed by providing a broken-line-shaped thermal bonding portion such that the non-thermal bonding portion faces the projection in a state where the intermittent projection is formed in the plastic film. With such a configuration, a gap can be easily formed between the opposing plastic films in the non-thermally bonded portion.

[0006] In the above-mentioned breathable bag, the plastic film near the other open end has an intermittent protruding portion having a fixed length in a direction perpendicular to the open end in parallel with the open end. By filling the contents,
A dashed thermal bonding portion is formed so that the non-thermal bonding portion faces the formed protrusion, and a gap can be formed between the opposing plastic films in the non-thermal bonding portion. The air-permeable bag can be easily deaerated from the bag.

[0007] A step of feeding out two continuous plastic films having thermal adhesiveness, and forming a protruding portion which is intermittently arranged on one of the plastic films in a direction perpendicular to the flow direction and has a fixed length in the flow direction, Forming the male and female hot presses at a constant interval in the flow direction, and laminating the other plastic film and one of the plastic films to form side-end heat-bonded portions at both ends in the flow direction. A step of forming a cylindrical shape, and using a hot plate for thermal bonding having a concave portion in a direction perpendicular to the flow direction, the two plastic films are formed such that the concave portion faces the protruding portion formed on one plastic film. A step of forming a dashed heat bonding portion composed of a non-heat bonding portion and a heat bonding portion having a gap between the plastic films by heat bonding; By manufacturing by a manufacturing method comprising a step of cutting a continuous cylindrical film in the vicinity of the attachment portion, excellent degassing properties are provided in which a gap is formed between the opposing plastic films in the non-heat-bonded portion of the dashed heat-bonded portion. A breathable bag can be easily manufactured.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a plan view showing a first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along a line II of FIG. 1, FIG. 3 is a plan view showing a second embodiment of the present invention, and FIG. II sectional views, FIG. 5, FIG. 6, FIG. 7, FIG. 8, and FIG. 9 are views showing a method of forming a gap between the plastic films in the non-thermally bonded portion of the dashed lined thermal bonded portion. Plastic film, 2a, 2b are side end thermal bonding parts, 3 is broken line thermal bonding part,
3a is a heat-bonded portion, 3b is a non-heat-bonded portion, 4 is a gap, 5 is a protruding portion, 6a is a forming female die, 6b is a forming male die, 7 is a hot bonding hot plate, 7a is a convex portion, 7b Denotes a concave portion, and 8 denotes a thermal bonding base plate.

A first embodiment of the present invention is as shown in FIGS. As shown in FIG. 1, the plastic film 11 and the plastic film 12 each having a quadrangular heat-adhesive property are superimposed on each other, and both ends are bonded together at the side end heat-bonded portions 2a and 2b as shown in FIG. A heat-bonded portion 3a and a non-heat-bonded portion 3b near the lower open end of the tubular body and parallel to the open end.
A dashed heat bonding portion 3 is formed and adhered, and the plastic film 11 is formed at the non-thermal bonding portion 3b of the dashed heat bonding portion 3.
And a plastic film 12 with a gap 4 formed therebetween. In the first embodiment, after filling the contents,
A linear thermal bonding portion is formed in the vicinity of the upper open end, or an intermittent linear thermal bonding portion is formed and sealed, and the air sealed in the bag when filling the contents is The air is mainly degassed through the gap 4 formed between the plastic film 11 and the plastic film 12 in the non-thermal bonding portion 3b of the dashed heat bonding portion 3.

As shown in FIG. 2, the cross-sectional shape of the dashed heat-bonded portion 3 of the first embodiment is the intermittently formed heat-bonded portion.
3a, non-thermally bonded portion between adjacent thermally bonded portions 3a
In FIG. 3B, the plastic film 11 is in a state of protruding upward, and the gap 4 is formed between the plastic film 11 and the plastic film 12. It is preferable that the length of the non-thermally bonded portion 3b is 4 to 6 mm, and the height of the gap 4 between the plastic films 11 and 12 is 0.5 to 3 mm. If the length of the non-thermally-bonded portion 3b is further increased, the contents may leak out. In the first embodiment, the length of the heat-bonded portion 3a is about twice as long as the length of the non-heat-bonded portion 3b. May be longer. In that case, the number of non-thermally bonded portions 3b formed in the dashed heat-bonded portion 3 is reduced, but degassing is improved by dispersing the non-thermally bonded portions 3b in the left-right direction of the bag and forming a plurality of non-thermally bonded portions. can do.

A second embodiment of the present invention is as shown in FIGS. 3 and 4 and is basically the same as the first embodiment, except that a plastic film near the upper open end of the cylindrical body is provided. 11, an intermittent projection 5 having a certain length in the vertical direction.
Are formed in a state of being arranged in parallel with the opening end. In the second embodiment, after filling the contents into the bag, the portion where the protrusion 5 is formed is parallel to the opening end as shown in FIG.
As shown in FIG. 5, a heat bonding hot plate 7 having a convex portion 7a and a concave portion 7b in a pressing portion is used so that the concave portion 7b of the heat bonding hot plate 7 faces the protrusion 5 of the plastic film 11. By performing the thermal bonding, a gap can be formed between the plastic films in the non-thermal bonding portion of the dashed heat bonding portion.
As described above, after filling the contents, a dashed heat bonding portion is also formed in the vicinity of the upper opening end to form a gap in the non-heat bonding portion. This makes it possible to obtain a very excellent air-permeable bag.

As shown in FIG. 4, the plastic film 11 and the plastic film 12 overlap each other in the cross-sectional shape of the portion where the protrusion 5 is formed in the plastic film 11 according to the second embodiment.
The protrusions 5 are intermittently formed at regular intervals on the reference numeral 11, the adjacent protrusions 5 are flat, and the plastic film 12 is in a flat state. The interval between the adjacent protrusions 5 is formed so as to correspond to the interval between the adjacent non-adhesion portions in the dashed heat bonding portion to be formed, and the length of the projection 5 is about twice the length of the flat portion. It is length. After filling the air-permeable bag of the second embodiment with the contents, a dashed heat bonding portion is formed so that the non-heat bonding portion of the dashed heat bonding portion corresponds to the portion where the protrusion 5 is formed. Thereby, a gap can be formed between the opposing plastic films 11 and 12 in the non-thermally bonded portion, so that the air enclosed therein can be quickly degassed. Further, since the length of the protruding portion 5 is about twice the length of the flat portion, when forming the non-thermally-bonded portion of the broken-line-shaped thermal bonding portion corresponding to the protruding portion 5, the protruding portion 5 is not formed. Even if a slight shift occurs in the left-right direction position of the thermal bonding portion, a gap can be formed in the non-thermal bonding portion.

To produce the breathable bag of the first embodiment,
At intervals equal to the vertical length of the bag in the direction perpendicular to the flow of the roll-shaped plastic film 11 having thermal adhesiveness,
As shown in FIG. 5, the plastic film 11 is hot-pressed with the female mold for molding 6a and the male mold for molding 6b to form intermittent protrusions 5 on the plastic film 11. The state in which the intermittent protrusions 5 are formed on the plastic film 11 is as shown in FIG. As shown in FIG. 7, a plastic film 11 having intermittent protrusions 5 formed on a flat plastic film 12 is superimposed, and heat-sealed side ends are formed at both ends in the flow direction to form a cylindrical shape. And
Next, as shown in FIG. 8, the plastic film 11 on which the protruding portions 5 are formed and the flat plastic film 12 are formed by the heat bonding hot plate 7 having the convex portions 7a and the concave portions 7b. As shown in FIG. 9, by pressing and applying heat between the heat bonding hot plate 7 and the heat bonding base plate 8 so that the concave portions 7 b correspond to the protruding portions 5, the dashed heat bonding portions 3 are formed. A gap 4 can be formed between the opposing plastic films 11 and 12 in the non-thermally bonded portion 3b. The continuous tubular body is cut in the vicinity of the dashed heat bonding portion 3 to obtain the breathable bag of the first embodiment.

The air permeable bag of the second embodiment is also manufactured by basically the same process as that of the first embodiment, but the flow of the plastic film 11 having a roll-like heat-adhesive property is reduced. At intervals equal to the vertical length of the bag in the perpendicular direction, as shown in FIG. 5, when forming the intermittent protrusions 5 on the plastic film 11 with the forming female die 6a and the forming male die 6b, The protrusions 5 intermittently arranged in the direction perpendicular to the flow are formed at two locations adjacent to each other in the flow direction. Next, as shown in FIG.
The plastic film 11 having the intermittent protrusions 5 formed thereon is overlapped, and only one side of the intermittent protrusions 5 formed adjacent to each other in the flow direction is provided with a heat bonding hot plate. 7 is pressed and heat-bonded between the hot-bonding hot plate 7 and the hot-bonding base plate 8 so that the concave portions 7b of the 7 correspond to the protruding portions 5. After the gap 4 is formed between the opposing plastic films 11 and 12, by cutting between two intermittent protrusions 5 adjacent in the flow direction, the breathable bag of the second embodiment can be manufactured.

Plastic film 1 having thermal adhesion
As the structure of 1,12, a laminate of a biaxially stretched plastic film excellent in strength and a heat-adhesive resin such as a polyolefin resin is generally used. As the biaxially stretched plastic film, biaxially stretched polyethylene terephthalate, biaxially stretched nylon, biaxially stretched polypropylene and the like are used, and as the polyolefin resin, low density polyethylene, medium density polyethylene, linear low density polyethylene, ethylene-acetic acid are used. Vinyl copolymers, ethylene-α olefin copolymers and the like are used. Instead of using a biaxially stretched plastic film, a laminate of linear low-density polyethylene and linear low-density polyethylene, a laminate of undrawn polypropylene and linear low-density polyethylene, or the like can also be used. In the case of this configuration, the elongation of the laminated film is large, so that the drop strength is excellent and the workability is excellent. In any case, since the plastic film is used as a breathable bag for packing 5 to 10 kg of rice or the like, a plastic film having excellent strength is preferable.

[0016]

According to the present invention, there is provided a bag in which a dashed heat-bonding portion is formed in the vicinity of one open end of a cylindrical body made of a plastic film having a heat-adhesive property and parallel to the opening end. It consists of a heat-bonded part and a non-heat-bonded part, and a gap is formed between the plastic films facing each other in the non-heat-bonded part. Since a gap is formed between the plastic films to be formed, the bag can be easily degassed through the gap, and the length of the non-heat-bonded portion is small so that the bag does not leak out of the contents. Can be. In the above-mentioned breathable bag, in the state where the intermittent protrusion is formed on one of the plastic films, by providing a dashed heat-bonding portion so that the non-heat-bonding portion faces the protrusion, the non-heat-bonding portion is formed. A gap can be easily formed between the opposing plastic films. In the above-described breathable bag, the plastic film in the vicinity of the other open end has a structure in which an intermittent protrusion having a certain length in a direction perpendicular to the open end is formed in parallel with the open end. After the object is filled, a gap can be formed between the opposed plastic films in the non-heat-bonded portion by thermally bonding in a broken line shape so that the non-heat-bonded portion faces the protruding portion. It can be a breathable bag that can be degassed. A step of feeding out two continuous plastic films having thermal adhesiveness, and forming a protrusion having a constant length in the flow direction while being intermittently arranged in a direction perpendicular to the flow direction on one of the plastic films, A step of forming at regular intervals in the flow direction by a female hot press, and laminating the other plastic film and one of the plastic films to form side end thermal bonding portions at both ends in the flow direction to form a cylinder The process of
By using a hot plate for thermal bonding having a concave portion in a direction perpendicular to the flow direction, the two plastic films are thermally bonded so that the concave portion is opposed to the protrusion formed on one plastic film. A process of forming a dashed heat-bonded portion consisting of a non-heat-bonded portion and a heat-bonded portion having a gap between the films, and a step of cutting a continuous tubular film near the dashed-line heat-bonded portion; In this way, it is possible to easily produce a breathable bag having excellent deaeration properties in which a gap is formed between the opposing plastic films in the non-heat-bonded portion of the dashed heat-bonded portion.

[Brief description of the drawings]

FIG. 1 is a plan view showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II in FIG.

FIG. 3 is a plan view showing a second embodiment of the present invention.

FIG. 4 is a sectional view taken along the line II-II in FIG.

FIG. 5 is a view showing a method of forming a gap between plastic films in a non-heat-bonded portion of a dashed heat-bonded portion.

FIG. 6 is a diagram showing a method of forming a gap between plastic films in a non-heat-bonded portion of a dashed heat-bonded portion.

FIG. 7 is a diagram showing a method of forming a gap between plastic films in a non-heat-bonded portion of a dashed heat-bonded portion.

FIG. 8 is a diagram showing a method of forming a gap between plastic films in a non-heat-bonded portion of a dashed heat-bonded portion.

FIG. 9 is a diagram showing a method of forming a gap between plastic films in a non-heat-bonded portion of a dashed heat-bonded portion.

[Explanation of symbols]

 11, 12 Plastic film 2a, 2b Side thermal bonding part 3 Dotted thermal bonding part 3a Thermal bonding part 3b Non-thermal bonding part 4 Gap 5 Projecting part 6a Female mold for molding 6b Male mold for molding 7 Hot plate for thermal bonding 7a Convex part 7b Concave part 8 Base plate for thermal bonding

Claims (4)

[Claims] 1. A dashed heat-bonded portion comprising a heat-bonded portion and a non-heat-bonded portion is formed near one open end of a tubular body made of a plastic film having heat-adhesiveness and parallel to the open end. A breathable bag, wherein a gap is formed between the plastic films facing each other in the non-heat-bonded portion of the broken-line-shaped heat-bonded portion. 2. The gap is formed by providing the broken-line-shaped thermal bonding portion such that the non-thermal bonding portion faces the projection in a state where an intermittent projection is formed in the plastic film. The breathable bag according to claim 1, wherein 3. The plastic film in the vicinity of the other open end is provided with an intermittent projecting portion having a predetermined length in a direction perpendicular to the open end and parallel to the open end. The breathable bag according to claim 1 or 2, wherein 4. A step of feeding two continuous plastic films having thermal adhesiveness, wherein one of the plastic films is intermittently arranged in a direction perpendicular to the flow direction and has a constant length in the flow direction. Forming a part at regular intervals in the flow direction by hot pressing of male and female molds, and laminating the other of the plastic films and the one plastic film and bonding the side ends to both ends in the flow direction. Forming a portion into a cylindrical shape, and forming the concave portion in the one plastic film using a hot bonding hot plate having a concave portion in a direction orthogonal to the flow direction and a flat plate hot bonding hot plate. The two plastic films are thermally bonded so as to face the projected portion, so that a non-thermally bonded portion and a thermally bonded portion having a gap between the plastic films can be formed. A method of manufacturing a breathable bag, comprising: a step of forming a dashed heat-bonded portion; and a step of cutting the continuous tubular film in the vicinity of the dashed heat-bonded portion.