JP2019182508A - Bag body for holding freshness and manufacturing method thereof - Google Patents

Abstract

To provide a bag body for holding freshness with very little in-flow of oxygen from the outside of the bag body which can hold freshness of contents for a long period, and a manufacturing method thereof, etc.SOLUTION: According to this invention, in a bag body for holding freshness 100 which is formed by a film 1, the bag body comprises a band-like connection region 6 in which two end portions 1a, 1b of the film are superposed and connected, and of which the width is from 5 mm to 15 mm, and the connection region has a plurality of supersonic connection portions 8 with the two end portions of the film connected mutually, and non-connection portions 10 which are arranged between the adjoining supersonic connection portions and where the superposed end portions of the film are not connected mutually, and the non-connection portion forms a non-straight air passage which communicates an inside space of the bag body and the outside of the bag body, and a width W of the air passage is 0.2 mm≤W≤3 mm, and a length L is 20 mm≤L≤50 mm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a freshness-keeping bag and a method for producing the same, and more specifically, a freshness-holding bag that can suppress a decrease in freshness of foods and fresh flowers that generate carbon dioxide during storage by respiration or fermentation, and It relates to the manufacturing method.

  A bag that can store foods that generate carbon dioxide by breathing or fermentation, such as vegetables, fruits, fresh flowers, coffee beans, processed foods, etc. while maintaining freshness, or fresh flowers can be stored for a long time There is an increasing need for bags.

  The bag body for storing foods and the like for a long period of time requires two contradictory functions of discharging carbon dioxide and water vapor generated inside and preventing inflow of oxygen from the outside. This is because if the discharge of carbon dioxide or water vapor is insufficient, the internal pressure may increase and the bag may be damaged, and if the inflow of oxygen is not prevented, the freshness of the contents will decrease due to oxidation.

  To meet such needs, non-joint portions arranged in stripes are provided in the heat seal portion of the bag body, and the fruit and vegetable packaging product (bag body) that uses this non-joint portion as a flow path that communicates with the outside of the bag body. ) Has been proposed (Patent Document 1). In this bag body, the non-joining part (flow path) has a straight (that is, elongated rectangular) planar shape having a width of 0.1 to 5 mm and a length of 1 to 20 mm.

  In this bag body, the flow path maintains the inside of the bag body in a state where the oxygen concentration is low and the carbon dioxide concentration is high, and the freshness of the fruits and vegetables inside is maintained. In this bag, the freshness of the contents can be maintained for a certain period of time. However, since the length of the flow path is relatively short, the flow of oxygen from the outside is relatively large, and the freshness of fruits and vegetables is maintained over a long period of time. It was difficult.

  In order to cope with this problem, a packaged product in which a vent hole having a width of 3 mm or more extending obliquely is provided in the center seal portion has been proposed (Patent Document 2). According to this configuration, the length of the ventilation path can be increased.

Japanese Patent No. 3259166 Japanese Patent No. 6052729

  However, in the configuration of the cited document 2, since the width of the passage opening (flow path) is relatively wide as 3 mm or more, dew condensation is likely to occur in the ventilation opening (vent passage). As a result, there is a problem that the internal space of the vent is blocked by moisture generated by condensation, the air flow in the vent is blocked, and the freshness cannot be sufficiently maintained.

  Further, in both configurations of Patent Document 1 and Patent Document 2, since the air passage is configured to extend linearly at the seal portion, there is a problem that the strength of the seal portion in the direction in which the air passage extends extends. there were.

  Further, in both configurations of Patent Document 1 and Patent Document 2, since the air passage is formed by heat sealing, there is a problem that it is difficult to accurately control the width and shape of the air passage to be formed.

  The present invention has been made in view of the above points, and has a very low oxygen inflow from the outside of the bag body, and can maintain the freshness of the contents for a long period of time, a manufacturing method thereof, and the like. The purpose is to provide.

  Another object of the present invention is to provide a freshness-keeping bag body in which a decrease in strength at a portion where an air passage is formed is suppressed, a manufacturing method thereof, and the like.

According to another preferred embodiment of the invention,
A freshness-keeping bag formed of a film,
A belt-like joining region having a width of 5 mm or more and 15 mm or less, wherein the two ends of the film are overlapped and joined;
The bonding region is disposed between a plurality of ultrasonic bonding portions in which two ends of the film are bonded to each other and the adjacent ultrasonic bonding portions, and the ends of the superimposed films are bonded to each other. And non-joined parts,
The non-joining portion constitutes a non-linear air passage that communicates the internal space of the bag body and the outside of the bag body,
The air passage has a width W of 0.2 mm ≦ W ≦ 3 mm, and a length L of 20 mm ≦ L ≦ 50 mm.
A freshness-maintaining bag body is provided.

According to such a configuration,
Since the air passage has a width W of 0.2 mm ≦ W ≦ 3 mm and a length L of 20 mm ≦ L ≦ 50 mm, the oxygen dioxide generated in the bag body is suppressed while suppressing the entry of oxygen through the air passage. Carbon and water vapor can be quickly discharged outside through the air passage.
In addition, since the air passage is non-linear, a decrease in strength of the joining region due to the air passage constituted by the non-joining portion is suppressed.

According to another preferred embodiment of the invention,
The film has an oxygen barrier layer.

According to another preferred embodiment of the invention,
The film has a thickness of 20 μm or more and 100 μm or less.

According to another aspect of the invention,
A bag-like freshness-keeping bag formed of a film, having a belt-like joining region having a width of 5 mm or more and 15 mm or less in which two ends of the film are overlapped and joined, and the joining region is A plurality of joints in which the two ends of the film are joined to each other, and a non-joint part in which the ends of the overlapped films arranged between the adjacent joints are not joined to each other. The non-joining portion constitutes a non-linear air passage that communicates the internal space of the bag body with the outside of the bag body, and the air passage has a width W of 0.2 mm ≦ W ≦ 3 mm. There is a method for producing a freshness-maintaining bag body having a length L of 20 mm ≦ L ≦ 50 mm,
Forming the joint by ultrasonic welding,
The manufacturing method of the bag body for freshness maintenance characterized by this is provided.

  According to such a configuration, since the joint portion is formed by ultrasonic welding, it is possible to accurately control the width and shape of the air passage constituted by the non-joint portion located between the adjacent weld portions. Become. As a result, it is possible to form an air passage having a dimension and shape that enables ventilation suitable for the contents to be stored.

  According to another aspect of the present invention, there is provided a bag manufacturing cylinder used for manufacturing the freshness maintaining bag.

  ADVANTAGE OF THE INVENTION According to this invention, the inflow of oxygen from the outside of a bag body is very little, and the freshness maintenance bag body which can maintain the freshness of the contents for a long period of time, its manufacturing method, etc. are provided.

  Furthermore, according to the present invention, there are provided a freshness-keeping bag body in which a decrease in strength in a portion where an air passage is formed is suppressed, a manufacturing method thereof, and the like.

It is a typical top view of bag 100 of a preferred embodiment of the present invention. It is typical sectional drawing along the II-II line of FIG. It is typical sectional drawing along the III-III line of FIG. It is typical drawing which shows the modification of the ventilation path comprised by a non-joining part. It is typical drawing which shows the modification of the ventilation path comprised by a non-joining part. It is typical drawing which shows the modification of the ventilation path comprised by a non-joining part. It is typical drawing which shows the modification of the ventilation path comprised by a non-joining part. It is typical drawing which shows the modification of the ventilation path comprised by a non-joining part. It is typical drawing which shows the modification of the ventilation path comprised by a non-joining part. It is a typical top view of the modification of a bag. It is drawing which shows typically the structure of the welding apparatus used by manufacture of a bag body. It is a typical perspective view which shows the external appearance of the welding horn of the welding apparatus of FIG. It is drawing which shows typically the bag body manufacture of embodiment of this invention. It is drawing which shows typically the bag body manufacture of embodiment of this invention. It is drawing which shows typically the cylindrical body for manufacturing the bag body of this invention.

  Hereinafter, the structure of the bag body 100 of preferable embodiment of this invention is demonstrated in detail along drawing. FIG. 1 is a schematic plan view of a bag body 100 according to a preferred embodiment of the present invention. 2 is a cross-sectional view taken along line II-II in FIG. 1, and FIG. 3 is a cross-sectional view taken along line III-III in FIG. In the present application, the ratio of dimensions of each element is not accurately shown in the drawings for the sake of clarity.

  In this embodiment, the bag body 100 is a bag body having a rectangular planar shape for storing food such as coffee. The size of the bag body 100 of this embodiment is 20 cm × 40 cm, but the present invention is not limited to this size.

  The bag body 100 of this embodiment is composed of the film 1. The film used in the bag body 100 is preferably an amorphous polymer film. Specific examples include films of polystyrene, acrylic resin, vinyl chloride, polycarbonate, styrene acrylonitrile copolymer, and the like.

  The film 1 may be a laminated film in which a plurality of films made of different materials are laminated. Examples of the laminated film include a laminated film in which a polystyrene film is laminated inside a polyester, polyethylene, or polypropylene film.

  As the film 1, a film obtained by laminating an oxygen barrier film and another film can also be used. As the oxygen barrier film, a known film such as a film made of a polymer containing vinyl alcohol or vinylidene chloride as a constituent component, a polymer film on which any of silica, alumina, and aluminum is deposited, a metal foil layer, and the like can be used. A laminated film in which polystyrene is laminated inside the oxygen barrier film can be used as the film of the present invention.

  The film 1 may be transparent or opaque. When the contents are deteriorated by sunlight, it is preferable to use an opaque packaging film. Moreover, the film which printed on the surface in order to improve the designability may be used.

  The thickness of the film 1 is preferably 10 to 300 μm, more preferably 15 to 200 μm, and still more preferably 20 to 100 μm. This is because if the thickness of the film is less than 10 μm, the strength of the bag may be insufficient, and if it exceeds 300 μm, it may be disadvantageous in terms of cost.

  The bag body 100 has a shape in which a horizontally long rectangular film 1 is folded in two along a center line extending in the vertical direction. The upper and lower ends of the bag body 100 are completely sealed by a top seal 2 and a bottom seal 4 formed by heat sealing. These seals 2 and 4 may be formed by other methods such as adhesion with an adhesive or sealing with a tape. In addition, the top seal portion can be formed using a fastener that can be opened and closed. Further, the top seal may be initially formed without filling the bag body 100 with the top seal without providing the top seal.

  Further, one side end (left end in FIG. 1) of the bag body 100 on which the both side end portions 1a and 1b of the film 1 are overlapped is a belt-like shape extending over the entire length of the overlapping portion of the side end portions 1a and 1b of the film 1. It is joined and closed by the joining region 6. In the bag body 100, the joining region 6 serves as a side seal portion.

  In the bag body 100 of this embodiment, the band-shaped joining region 6 is set to have a width of 5 mm or more and 15 mm or less. The width of the band-shaped joining region 6 is more preferably 6 mm or more and 13 mm or less, and further preferably 8 mm or more and 11 mm or less.

  When the width of the bonding region 6 is less than 5 mm, there may be problems such as insufficient strength of the bonded portion and difficulty in securing the length of the air passage. In addition, when the width of the bonding region 6 exceeds 15 mm, there may be problems such as non-uniform bonding and difficulty in keeping the width of the air passage constant.

  In the band-shaped bonding region 6, a plurality of ultrasonic fusion bonding portions (ultrasonic bonding portions) 8 each having a thick V-shaped shape are arranged at predetermined intervals in the longitudinal direction. Each ultrasonic fusion part 8 is a part in which both side ends 1a and 1b of the film 1 are joined and integrated by ultrasonic fusion, and both side ends 1a and 1b of the film 1 are connected to each other as will be described later. These are formed by fusing them with an ultrasonic fusing device (FIGS. 1 and 2).

  Between the adjacent ultrasonic fusion parts 8 and 8, it is set as the non-joining part 10 in which the side edge parts 1a and 1b of the laminated | stacked film 1 are not joined (fused). As described above, since each ultrasonic fusion part 8 has a V-shape, as shown in FIG. 1, the non-bonding part 10 between adjacent ultrasonic fusion parts 8 is also present. It has a V shape.

  The inner end of the non-joining portion 10 opens into the internal space of the bag body 100, and the outer end of the non-joining portion 10 opens into the external space of the bag body 100. As a result, the air passage 10 constituted by the non-joining portion 10 becomes a V-shaped (that is, non-linear) air passage having a constant width that communicates the internal space of the bag body 100 with the outside (see FIG. 1 and FIG. 1). FIG. 3).

  As a result, in the bag body 100 of the present embodiment, the V-shaped air passages 10 that are oriented in the same direction are formed at regular intervals in the side seal portion.

  In the bag body 100 of the present embodiment, the width W of the non-joining portion (ventilation path) 10 is set to 0.2 mm or more and 3 mm or less. The width W of the air passage 10 is more preferably from 0.3 mm to 2.5 mm, and more preferably from 0.5 mm to 2.0 mm.

  By setting the width W of the air passage 10 to 0.2 mm or more and 3.0 mm or less, both the discharge of carbon dioxide and water vapor generated inside the bag body 100 and the prevention of oxygen intrusion from the outside of the bag body 100 are achieved. Is possible. Further, when the bag body 100 is moved, the gas hardly flows inside the air passage 10 and oxygen hardly enters from the outside.

  In the bag body 100 of this embodiment, the length L of the air passage 10 is set to 20 mm or more and 50 mm or less. The length L of the air passage 10 indicates a length along the central axis of the air passage 10 from the inner end to the outer end of the air passage 10.

  The length L of the air passage 10 is more preferably 22 mm or greater and 45 mm or less, and even more preferably 25 mm or greater and 40 mm or less.

  In the bag body 100 of the present embodiment, the length L of the air passage 10 is set to 20 mm or more and 50 mm or less, thereby releasing carbon dioxide and water vapor generated inside the bag body 100 and oxygen from the outside of the bag body 100. Both intrusion prevention.

  Further, in the bag body 100 of the present embodiment, the ratio L / W between the length L and the width W of the ventilation path 10 is set to 10 or more and 200 or less. When the ratio L / W of the length L to the width W is less than 10, the storage stability of the contents is remarkably deteriorated, and when this ratio exceeds 200, moisture is condensed inside the air passage and the carbon oxide This is because the discharge may be insufficient.

  The ratio L / W of the length L to the width W of the air passage 10 is more preferably 15 or more and 150 or less, and further preferably 20 or more and 100 or less.

  Furthermore, in the bag body 100 of this embodiment, the space | interval of the ventilation path 10 is set to 1 mm or more and 100 mm or less. By setting the interval between the air passages 10 to 1 mm, the accurate shape of the air passage 10 can be secured. Moreover, the required number of ventilation paths 10 can be provided by setting it as 30 mm or less.

  The interval of the air passage 10 is more preferably 2 mm or more and 50 mm or less, and further preferably 3 mm or more and 15 mm or less.

  In the bag body 100 of the present embodiment, the number of air passages 10 formed in the bag body 100 is set to 1 or more, preferably 3 to 100, and more preferably 5 to 75.

  In particular, when storing fruits and vegetables that generate a relatively large amount of carbon dioxide during storage, the number of air passages is set to 3 or more and 100 or less, more preferably 5 or more and 75 or less. This is preferable because it is possible to prevent the carbon dioxide from being insufficiently blocked by water.

4 to 9 are schematic drawings showing modified examples of the shape of the non-linear air passage 10.
The air passage of the present invention is formed by a plurality of bent straight portions such as an inverted “h” -shaped air passage 104 as shown in FIG. 4 and a “W” -like air passage 105 as shown in FIG. It may be a configured air passage.

  The air passage of the present invention may be an inclined “W” -shaped air passage 106 as shown in FIG. Furthermore, the air passage of the present invention may be air passages 107, 108, and 109 having a shape in which a plurality of curved portions as shown in FIGS.

  Furthermore, the air passage of the present invention is not limited to the above specific example, and includes other broken lines, curved shapes, and combinations of these.

  Moreover, in the bag body 100 of the said embodiment, although the strip | belt-shaped joining area | region 6 which has the ultrasonic fusion part (ultrasonic joining part) 8 was provided in the side seal part, the ultrasonic fusion part (ultrasonic wave) The band-shaped joining region 6 having the joining part) 8 may be formed in a seal part other than the side seal part, for example, the top seal 2 and the bottom seal 4.

  For example, in the bag 200 sealed with the center seal portion 20 as shown in FIG. 10, the center seal portion 20 is not connected to the above-described ultrasonic fusion portion (ultrasonic bonding portion) 8. It is good also as a strip | belt-shaped joining area | region which has a junction part (air passage).

  Furthermore, although the bag body 100 of the said embodiment was comprised by accumulating the both ends of one film, it may be comprised using the some film.

  Next, the manufacturing method of the bag body 100 of the embodiment of the present invention will be described. The manufacturing method of this embodiment forms the said bag body etc. by joining two side edge part 1a, 1b of the rectangular-shaped film 1 partially by the ultrasonic welding method.

  In the manufacturing method of this embodiment, first, a horizontally long rectangular film 1 constituting the bag body 100 is prepared. Next, the film 1 is folded in two along a center line extending in the vertical direction, and both side end portions 1a and 1b are overlapped.

  Next, at least the two side ends 1a and 1b of the superposed film 1 are heated to a predetermined temperature (30 to 75 degrees Celsius). Heating is preferably performed by a method such as a heating roll or infrared heating.

  Next, the heated film is neutralized. Since the heated film has a low elastic modulus and becomes supple, it is easily charged due to an increase in the contact area when it comes into contact with an object such as a transport roll. In order to eliminate this electrification, it is preferable to perform static elimination before ultrasonic welding.

  Specifically, neutralization is performed using an ion wind, a neutralization brush, or the like. The neutralization is preferably performed so that the surface potential of the film after neutralization is 1 kv or less. The surface potential can be measured, for example, with a surface potential meter MODEL341B manufactured by Trek Japan. By performing the static elimination, the adhesion of dust due to such charging is suppressed.

  The surface potential of the film after static elimination is preferably 1 kV or less in absolute value from the viewpoint of preventing dust. The surface potential can be measured, for example, with a surface potential meter MODEL341B manufactured by Trek Japan.

  Next, the upper and lower ends of both side end portions 1a and 1b of the overlapped film are joined by heat sealing or the like, and the both end portions 1a and 1b of the overlapped film are temporarily fastened so that the relative positions are not shifted. By this temporary fastening, the relative position shift of the both end portions 1a and 1b of the superimposed film is prevented.

  Next, a joining part is provided by forming a plurality of linear ultrasonic fusion parts 8 at predetermined intervals on both side edges 1a and 1b of the film 1 by ultrasonic welding.

FIG. 11 is a drawing schematically showing the configuration of a welding apparatus 300 used in the ultrasonic welding method.
As shown in FIG. 11, the welding apparatus 300 includes an ultrasonic oscillator 302 that converts commercial electricity of 50 Hz or 60 Hz into a high-frequency signal of about 15 to 70 KHz, and a converter 304 that converts this signal into mechanical vibration. A booster 306 that amplifies the mechanical vibration, a horn 308 that transmits the amplified vibration to the object to be welded (film 1), and a seat 310 that sandwiches the film 1 between the horn 308 and the horn 308. . It is preferable that the receptacle 310 can control the temperature.

  The welding apparatus 300 of this embodiment is a rotary type welding apparatus in which the horn 308 has a disk shape as shown in FIG. A plurality of V-shaped protrusions 308 b corresponding to the shape of the ultrasonic fusion part 8 of the bag body 100 are continuously formed on the outer peripheral surface 308 a of the disk-shaped horn 308 at a predetermined interval.

  In the welding operation using the rotary type welding apparatus 300, the linear ultrasonic fusion part 8 is continuously formed at the side end parts 1a and 1b of the film. Specifically, the disk-shaped horn 308 is rotated in a state where the side end portions 1a and 1b of the overlapped film are sandwiched between the horn 308 and the receiving seat 310, and the side end of the long film As shown in FIG. 13, the bonding region 6 having a plurality of ultrasonic fusion portions 8 is continuously formed in the portions 1 a and 1 b.

  Furthermore, the film in which the side end portions 1a and 1b are joined in the joining region 6 and formed into a cylindrical shape is formed with a top seal 2 and a bottom seal 4 to form a bag body 100 (FIG. 14). The top seal 2 is generally formed after the contents are accommodated in the bag body 100.

  Next, the cylindrical body 400 used for manufacturing the bag body 100 of the embodiment will be described. FIG. 15 is a schematic front view of the bag cylinder 400 of the present embodiment.

  As shown in FIG. 15, the cylindrical body 400 for bag according to the present embodiment is obtained by folding a long film 401 in the width direction along the longitudinal center line and overlapping both end portions. The overlapping both end portions are joined by a joining region 406 similar to that of the bag body 100 of the first embodiment.

  In the joint region 406, joint portions 408 and non-linear air passages 410 similar to those of the bag body 100 of the first embodiment are alternately formed.

  As shown by a dotted line in FIG. 15, this elongated bag body 400 is cut in the horizontal direction, and the upper and lower ends are sealed by a bottom seal portion and a top seal portion, and the bag body 100 of the first embodiment is It uses as a similar form.

  The present invention is not limited to the above-described embodiment, and various changes and modifications can be made within the scope of the technical idea described in the claims.

  Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1
A styrene acrylonitrile copolymer film having a length of 40 cm, a width of 40 cm, and a thickness of 20 μm was used as the film. Both surfaces of the film were neutralized using a fan type static eliminator KD-410 manufactured by Kasuga Electric Co., Ltd. The surface potential of the film after neutralization was set to −1 to +1 kV.

  Thereafter, using an ultrasonic fusion apparatus provided with a disk-shaped horn, a joint portion having a width of 10 mm as shown in FIG. 1 was formed. The oscillation frequency of the horn was 20 KHz, the vibration amplitude was 15 μm, the pressing pressure was 250 N, and the joining time was 0.2 seconds.

  The shape of the air passage is the shape shown in FIG. 7, the interval between the air passages is 10 mm, the width of the air passage is 0.8 mm, the width L of the air passage is 24 mm, and L / W is 30. The interval between the air passages was 12 mm. Next, a bottom seal portion was formed by heat sealing.

  When the air passage of the bag body thus manufactured was visually observed, there was no foreign matter in the air passage portion, and the width of the air passage was constant.

  150 g of commercially available leek was put into this bag, and a top seal part was formed by heat sealing to obtain a bag. When this bag was stored at 15 ° C. for 14 days, there was no change in the appearance of the leek of the contents, and it was edible.

(Example 2)
The film material is changed to a stretched polypropylene / unstretched polypropylene (20 μm / 30 μm) laminated film, the shape of the air passage is the “W” shape of FIG. 5, the air passage width is 1.2 mm, and the air passage width L is 30 mm. , L / W25, and the interval between the ventilation paths was set to Example 2 under the same conditions as Example 1 except that the distance was 6 mm.

  150 g of commercially available leek was put into this freshness-keeping bag body, and a top seal portion was formed by heat sealing to obtain a bag body. When this bag was stored at 15 ° C. for 14 days, there was no change in the appearance of the leek of the contents, and it was edible.

(Example 3)
As the film, an aluminum-deposited polyethylene terephthalate / unstretched polypropylene (16 μm / 30 μm, laminated so that the aluminum-deposited surface and the unstretched polypropylene are in contact) was used, and the unstretched polypropylene surfaces were ultrasonically welded to each other.

  The air passage was the air passage shown in FIG. 9, and the width and length of the air passage were 1.5 mm and 40 mm, respectively, and L / W 26.7. Moreover, the space | interval between ventilation paths was 25 mm.

Example 3 was carried out in the same manner as Example 2 except for the above. When the air passage of the obtained freshness-keeping bag body was visually observed, there was no foreign matter in the air passage portion, and the width of the air passage was constant. Moreover, there was no film shift at the stripe-shaped joint and the appearance was good.
When commercially available leek was put into this bag and stored at 15 ° C. for 14 days, the leek of the contents had no apparent change and was edible.

Example 4
The width and length of the air passage were 1.0 mm and 80 mm, respectively, and the value of L / W was 80.0. Moreover, it was set as Example 4 on the same conditions as Example 3 except the point which set the space | interval between ventilation paths to 80 mm. When the air passage of the obtained freshness-keeping bag body was visually observed, there was no foreign matter in the air passage portion, and the width of the air passage was constant. Moreover, there was no film shift at the stripe-shaped joint and the appearance was good. When commercially available leek was put into this bag and stored at 15 ° C. for 14 days, the leek of the contents had no apparent change and was edible.

(Example 5)
Instead of forming the top seal part by heat sealing, a fastener was attached to this part so that it could be opened and closed. Other than that, Example 5 was used under the same conditions as Example 1. When the air passage of the obtained freshness-keeping bag body was visually observed, there was no foreign matter in the air passage portion, and the width of the air passage was constant. Moreover, there was no film shift at the stripe-shaped joint and the appearance was good. When commercially available leek was put into this bag and stored at 15 ° C. for 14 days, the leek of the contents had no apparent change and was edible.

(Example 6)
Using the same film as in Example 2, a bag body was manufactured by the following method.
First, static electricity was removed from both sides of a 200 cm long and 40 cm wide film using a fan type static eliminator KD-410 manufactured by Kasuga Electric Co., Ltd. The surface potential of the film after neutralization was set to −1 to +1 kV. Next, both ends were ultrasonically welded in the same manner as in Example 2 to obtain a cylindrical bag body.

  The bag body was cut to a length of 500 mm, and the upper end and the lower end were heat sealed to obtain four freshness maintaining bags.

100: bag body 1: film 2: top seal 4: bottom seal 6: joining region 8: ultrasonic fusion part (joining part)
10: Non-joining part (air passage)

Next, a joining part is provided by forming a plurality of ultrasonic fusion parts 8 at predetermined intervals on both side edges 1a and 1b of the film 1 by ultrasonic welding.

Claims (8)

A freshness-keeping bag formed of a film,
A belt-like joining region having a width of 5 mm or more and 15 mm or less, wherein the two ends of the film are overlapped and joined;
The bonding region is disposed between a plurality of ultrasonic bonding portions in which two ends of the film are bonded to each other and the adjacent ultrasonic bonding portions, and the ends of the superimposed films are bonded to each other. And non-joined parts,
The non-joining portion constitutes a non-linear air passage that communicates the internal space of the bag body and the outside of the bag body,
The air passage has a width W of 0.2 mm ≦ W ≦ 3 mm, and a length L of 20 mm ≦ L ≦ 50 mm.
A bag for maintaining freshness. The film has an oxygen barrier layer;
The freshness-keeping bag body according to claim 1. The film has a thickness of 20 μm or more and 100 μm or less.
The freshness-keeping bag body according to claim 1 or 2. A bag-like freshness-keeping bag formed of a film, having a belt-like joining region having a width of 5 mm or more and 15 mm or less in which two ends of the film are overlapped and joined, and the joining region is A plurality of joints in which the two ends of the film are joined to each other, and a non-joint part in which the ends of the overlapped films arranged between the adjacent joints are not joined to each other. The non-joining portion constitutes a non-linear air passage that communicates the internal space of the bag body with the outside of the bag body, and the air passage has a width W of 0.2 mm ≦ W ≦ 3 mm. There is a method for producing a freshness-maintaining bag body having a length L of 20 mm ≦ L ≦ 50 mm,
Forming the joint by ultrasonic welding,
The manufacturing method of the bag body for freshness maintenance characterized by the above-mentioned. The step of forming the joint is a step of continuously forming the joint on the film while rotating a disk-shaped ultrasonic welding horn with respect to the film.
The manufacturing method of the bag body for freshness maintenance of Claim 4. An oxygen barrier film is used as the film,
The manufacturing method of the bag body for freshness maintenance of Claim 4 or 5. The film has a thickness of 20 μm or more and 100 μm or less.
The manufacturing method of the bag body for a freshness maintenance of any one of Claims 4 thru | or 6.   A cylinder for manufacturing a bag used for manufacturing the bag for maintaining freshness according to any one of claims 1 to 3.

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