JP4801104B2 - Method for producing packaging bag for maintaining freshness of fruits and vegetables and packaging bag for maintaining freshness of fruits and vegetables manufactured by the same method - Google Patents

Description

  The present invention relates to a method for producing a packaging bag suitable for maintaining the freshness of fruits and vegetables, and a packaging bag produced by the method.

  Conventionally, there is a packaging bag formed from a biaxially stretched polypropylene film (hereinafter also referred to as “OPP film”) that is excellent in economic efficiency, transparency, heat-weldability, and appearance.

  And in such a packaging bag, the gas permeability is too low, it becomes an excessively low oxygen and high carbon dioxide state, and the quality deterioration tends to proceed rapidly, so generally the upper part of the bag is left unsealed, Alternatively, it is lightly folded and taped.

  In addition, there is a type in which fine holes are formed in the packaging bag to suppress gas permeability (for example, see Patent Documents 1 and 2).

Further, as another means for improving gas permeability, a packaging bag is provided in which a polyethylene film having better gas permeability than an OPP film is used and the OPP film and the polyethylene film are bonded together in a bag shape. (For example, refer to Patent Document 3).
JP-A-2-85181 Japanese Patent Laid-Open No. 6-22686 JP 2005-112442 A

  However, if the packaging bag is not sealed, the original freshness maintaining effect is not exhibited, and there is a problem that the freshness is lowered in a very short time.

  Further, a packaging bag in which fine holes are formed after sealing is expensive because an operation step for forming fine holes is required.

  Further, as in the packaging bag described in Patent Document 3, simply by heat welding an OPP film and a polyethylene film, the strength of the welded portion is very low, so if the bag cannot be formed, or even if it can be made vegetable In some cases, it could not withstand the weight of fruits and vegetables.

  The present invention has been made in view of such circumstances, and even when fruits and vegetables are sealed, the oxygen and carbon dioxide concentrations in the bag can be maintained at suitable values by adjusting the thickness of the film. On the other hand, the manufacturing method of the packaging bag provided with the outstanding economical efficiency, transparency, heat welding property, and appearance, and the packaging bag manufactured by the same method are provided.

In order to solve the above-mentioned problem, in the method for producing a packaging bag for maintaining freshness of fruits and vegetables according to the present invention, it has a thickness of 8 to 30 μm and an oxygen permeability at 20 ° C. of 1000 to 3750 cc / m ² · day · atm. A first roll wound with a biaxially stretched polypropylene film and a laminated film having a thickness of 12 to 44 μm and an oxygen permeability at 20 ° C. of 2500 to 20000 cc / m ² · day · atm and a second roll used was the a biaxially oriented polypropylene film and the laminated film and a thermal fusing while manufacturing method of freshness packaging bag for fresh produce to bag manufacturing by welding the ends, the laminated film, low density high pressure polyethylene layer having a thickness of 10 to 30 [mu] m, is made by forming a sandwich of polypropylene layer having a thickness of 1 to 7 [mu] m, biaxially oriented polypropylene drawn from the first roll And film and the laminated film pulled out from the second roll, the overlapping step of overlapping while conveying respectively, the superposed films, while transporting in a predetermined direction, while the heat fused along a same predetermined direction seal The biaxially stretched polypropylene film melted while being thermally melted by contacting a hot blade from the biaxially stretched polypropylene film side in a direction intersecting the forming direction of the bottom formed in the bottom forming step And a bag forming step of forming a side portion by entangled with and sealing the laminated film and forming the film into a bag shape.

Further, in the method for producing a packaging bag for maintaining freshness of fruits and vegetables according to the present invention, biaxially oriented polypropylene having a thickness of 8 to 30 μm and an oxygen permeability at 20 ° C. of 1000 to 3750 cc / m ² · day · atm A first roll wound with a film, and a second roll wound with a laminated film having a thickness of 11 to 37 μm and an oxygen permeability at 20 ° C. of 2500 to 20000 cc / m ² · day · atm the used, the a biaxially oriented polypropylene film and the laminated film and a thermal fusing while the method of producing freshness retaining packaging bag for fresh produce to bag manufacturing by welding the ends, the laminated film is 10 and a low-density high-pressure polyethylene layer having a thickness of 30 .mu.m, are those having a polypropylene layer having a thickness of 1 to 7 [mu] m, the biaxially oriented polypropylene film drawn out from the first roll, from the second roll pull The stacking process of stacking the laminated film facing each other while facing each other and transporting them, and transporting the stacked films in a predetermined direction, sealing while thermally fusing along the predetermined direction In the direction intersecting the forming direction of the bottom formed in the bottom forming step and the bottom forming step, the biaxially stretched polypropylene film melted while contacting the hot blade from the biaxially stretched polypropylene film side and thermally fusing And a bag forming step of forming a side portion by entwining and sealing the laminated film, and forming the film into a bag shape.

Furthermore, the manufacturing method of the packaging bag for maintaining freshness of fruits and vegetables according to the present invention has the following features.

(1) In the bottom portion forming step, 3 seals while fusing at a temperature of 40 to 400 ° C., in the bag forming process, the seal to Rukoto while fusing at a temperature of 3 60-420 ° C..

(2) In the bottom forming step, the tension of the biaxially stretched polypropylene film drawn from the first roll is larger than the tension of the laminated film drawn from the second roll.

Moreover, in the packaging bag for freshness preservation of fruits and vegetables concerning the present invention, it decided to manufacture with the manufacturing method of the packaging bag given in any 1 paragraph of Claims 1-7.

The method for producing a freshness-keeping packaging bag according to claim 1, wherein the biaxially oriented polypropylene has a thickness of 8 to 30 µm and an oxygen permeability at 20 ° C of 1000 to 3750 cc / m ² · day · atm. A first roll wound with a film, and a second roll wound with a laminated film having a thickness of 12 to 44 μm and an oxygen permeability at 20 ° C. of 2500 to 20000 cc / m ² · day · atm the used, the a biaxially oriented polypropylene film and the laminated film and a thermal fusing while the method of producing freshness retaining packaging bag for fresh produce to bag manufacturing by welding the ends, the laminated film is 10 the low density high pressure polyethylene layer having a thickness of 30 .mu.m, is made by forming a sandwich of polypropylene layer having a thickness of 1 to 7 [mu] m, and biaxially oriented polypropylene film drawn out from the first roll, the second of The stacking step of stacking the laminated films drawn from the rolls while transporting each, the bottom forming step of sealing while transporting the stacked films in a predetermined direction and thermally fusing along the predetermined direction, In a direction crossing the forming direction of the bottom formed in the bottom forming step, a hot blade is brought into contact from the biaxially stretched polypropylene film side , and the biaxially stretched polypropylene film melted while thermally fusing is entangled with the laminated film. Forming a side portion by sealing, and forming a bag into a bag shape, so that one side is an OPP film having economic efficiency, transparency, thermal weldability and appearance, and the other side Can be a laminated film having a polyethylene film with good gas permeability, and even if the packaging bag is sealed, the freshness of the fruits and vegetables stored in it can be maintained. One possible can be produced packaging bag capable.

The front Symbol biaxially oriented polypropylene film has a thickness of 8 to 30 m, the laminated film is sandwiched and a low-density high-pressure polyethylene layer having a thickness of 13～18Myuemu, the same low density high pressure polyethylene layer sandwiched Since the two polypropylene layers having a thickness of 1 to 7 μm are laminated to a thickness of 17 to 32 μm, the oxygen permeability of the manufactured packaging bag can be set to an appropriate state. The biaxially stretched polypropylene film has an oxygen permeability at 20 ° C. of 1000 to 3750 cc / m ² · day · atm, and the laminated film has an oxygen permeability at 20 ° C. of 2500 to 20000 cc / m ² · day · atm. Therefore, the oxygen permeability of the manufactured packaging bag can be set to an appropriate state.

Moreover, in the manufacturing method of the packaging bag for freshness preservation of fruit and vegetables of Claim 2 , it has a thickness of 8-30 micrometers, and the oxygen permeability in 20 degreeC is 1000-3750cc / m < ² > * day * atm. A first roll wound with a stretched polypropylene film, and a second roll wound with a laminated film having a thickness of 11 to 37 μm and an oxygen permeability at 20 ° C. of 2500 to 20000 cc / m ² · day · atm using a roll, wherein a biaxially oriented polypropylene film and the laminated film and a thermal fusing while the method of producing freshness retaining packaging bag for fresh produce that the end bag manufacturing by welding together, the laminated film , and a low-density high-pressure polyethylene layer having a thickness of 10 to 30 [mu] m, are those having a polypropylene layer having a thickness of 1 to 7 [mu] m, the the first biaxially oriented polypropylene film drawn out from the roll, the second From the roll The stacked layer film is pulled out with the polypropylene layer facing each other and stacked while being transported, and the stacked film is transported in a predetermined direction and sealed while being thermally fused along the predetermined direction. In the direction intersecting the forming direction of the bottom formed in the bottom forming step and the bottom forming step, the biaxially stretched polypropylene film melted while contacting the hot blade from the biaxially stretched polypropylene film side and thermally fusing It is decided to have a bag forming step that forms a side part by entangled and sealed with a laminated film, and makes the film into a bag shape, so that one side is economical, transparent, heat weldable, and attractive. OPP film provided, and the other side can be a laminated film having a polyethylene film with good gas permeability, and can be laminated even if the packaging bag is sealed By changing the thickness of Irumu, it is possible to produce a packaging bag having a gas permeability which can maintain the freshness of the housing and the fruits or vegetables inside.

The front Symbol biaxially oriented polypropylene film has a thickness of 8 to 30 m, the laminated film, and a low-density high-pressure polyethylene layer having a thickness of 10 to 30 [mu] m, and a polypropylene layer having a thickness of 1~7μm laminated, because that you are the thickness of 11～37Myuemu, be housed vegetables and fruits and vegetables can exhibit a sufficient strength, moreover, it is possible to manufacture a highly gas-permeable packaging bag.

The oxygen permeability at 20 ° C. before Symbol biaxially oriented polypropylene film is ^{1000~3750cc / m 2 · day · atm} , an oxygen permeability at 20 ° C. of the laminated film 2500~20000cc / m ² · day · Since it is assumed to be atm, the oxygen permeability of the manufactured packaging bag can be set to an appropriate state.

In the manufacturing method of the fruits or vegetables Freshness packaging bag according to claim 3, in the bottom portion forming step, 3 seals while fusing at a temperature of 40 to 400 ° C., in the bag forming process, 3 60-420 Since sealing is performed while fusing at a temperature of ° C., an OPP film and a laminated film having different melting points can be welded without distortion.

Moreover, in the manufacturing method of the packaging bag for freshness preservation of fruit and vegetables of Claim 4 , in the bottom part formation process, the tension | tensile_strength of the unstretched polypropylene film pulled out from the 2nd roll is the laminated | multilayer film pulled out from the 1st roll. Since the tension is smaller than the tension, the OPP film and the laminated film having different melting points can be further welded without distortion.

Moreover, in the packaging bag for freshness preservation of fruit and vegetables of Claim 5 , since it manufactures with the manufacturing method of the packaging bag for freshness maintenance of fruit and vegetables of any one of Claims 1-4 , a packaging bag is sealed. Even so, the packaging bag can maintain the freshness of the fruits and vegetables stored therein.

  In the manufacturing method of the packaging bag which concerns on this invention, using the 1st roll which wound the biaxially stretched polypropylene film, and the 2nd roll which wound the laminated film, a biaxially stretched polypropylene film, the said laminated film, In the manufacturing method of a packaging bag for making a bag while heat-treating, the laminated film has a three-layer resin layer formed by sandwiching a low-density high-pressure polyethylene layer with a polypropylene layer, and is drawn from a first roll. The biaxially stretched polypropylene film and the laminated film drawn from the second roll are stacked while being transported, and the stacked films are heat-treated along the predetermined direction while transporting the stacked films in a predetermined direction. Heat treatment in a direction crossing the forming direction of the bottom formed in the bottom forming step and the bottom forming step of sealing while sealing While sealing to form a side, and a bag forming step of the film a bag shape.

  That is, in the present invention, the OPP film wound around the first roll and the laminated film wound around the second roll are transported and overlapped with each other with different tensions. Crossing the bottom forming process in which the film is transported in a predetermined direction and the heated hot blade is brought into contact with the predetermined direction and sealed while thermally fusing, and the forming direction of the bottom formed in the bottom forming process A hot blade heated in the direction, sealed while thermally fusing to form a side part, and a side part forming step for making the film into a bag shape, and transporting and storing the formed packaging bag on a conveyor Like to do.

  Therefore, an OPP film having a different melting point and a laminated film can be heat-sealed into a bag shape, and a packaging bag capable of maintaining the freshness of fruits and vegetables stored therein even when the packaging bag is sealed. It can be manufactured continuously in a series of process flows.

  Here, the laminated film is also referred to as a co-pressing film, and may be one in which a low-density high-pressure polyethylene layer is formed in a sandwich shape with a polypropylene layer, or may have a low-density high-pressure polyethylene layer and a polypropylene layer. .

  In other words, a packaging for forming a bag while heat-treating the biaxially stretched polypropylene film and the laminated film using a first roll wound with the biaxially stretched polypropylene film and a second roll wound with the laminated film. In the bag manufacturing method, the laminated film has a low-density high-pressure polyethylene layer and a polypropylene layer and is composed of two resin layers. The biaxially stretched polypropylene film drawn from the first roll has a second The polypropylene film surface of the laminated film drawn out from the roll is opposed to each other and stacked while being transported, and the stacked films are transported in a predetermined direction while being heat-treated along the predetermined direction. The bottom forming step for sealing and the heat treatment in the direction intersecting the forming direction of the bottom formed in the bottom forming step Sealed to form the sides, and the bag forming step of the bag-shaped film, may be a manufacturing method of the packaging bag with. In this case, the polypropylene film of the laminated film drawn out from the second roll is made to face the biaxially stretched polypropylene film drawn out from the first roll.

  If the laminated film is a low-density high-pressure polyethylene layer formed in a sandwich with a polypropylene layer, the polyethylene layer can be firmly reinforced, so a packaging bag that can withstand relatively heavy vegetables and fruits and vegetables. Can be manufactured.

  Further, as a feature of the packaging bag according to the present invention, since the laminated film is a co-pressed film composed of a low-density high-pressure polyethylene layer and a polypropylene layer, the tensile fracture elongation is very high, relatively heavy vegetables, fruits and vegetables, etc. Even if it inserts, since tension | tensile_strength spreads over the wide range of a bag and force does not concentrate on welding parts, such as a bottom part and a side part of a packaging bag, the intensity | strength of a packaging bag can be improved.

  In addition, when the laminated film has a two-layer structure of a low-density high-pressure polyethylene layer and a polypropylene layer, oxygen and carbon dioxide can be efficiently transmitted while reinforcing the polyethylene layer. A packaging bag that can maintain the freshness of fruits and vegetables for a relatively long time can be manufactured.

  In addition, here, when the heated hot blade is brought into contact with the stacked films and thermally melted, the film having a low melting point is thermally fused while the thermal blade is brought into contact with the film from the side having a high melting point and thermally melted. More specifically, it may be blown by contacting a hot blade from the side of the OPP film having a high melting point.

  According to such a thermal fusing method, biaxially stretched polypropylene (hereinafter referred to as OPP) melted at the end of the OPP film at the moment of fusing with a hot blade, is also blown with the hot blade. Since the ends of the laminated film can be entangled, the ends of the stacked films can be welded together without distortion, and the strength of the welded portion can be made sufficient.

  The temperature of the hot blade is such that the film wound on the first roll and the film wound on the second roll are superposed and thermally fused to form a bag, and the first roll and the first roll When the roll of 2 is an OPP film, the temperature is lower than the temperature when the laminated film is thermally fused with a hot blade, and the first roll and the second roll are laminated films. It is preferable to set the temperature higher than the temperature at which the film is thermally fused with a hot blade.

  More specifically, by setting the temperature to 340 to 400 ° C. in the bottom portion forming step and 360 to 420 ° C. in the side portion forming step, the packaging portion is efficiently packaged while keeping the welded portion obtained by thermally fusing the stacked films. Can be manufactured.

  In the bottom forming step, the tension of the laminated film drawn from the second roll is adjusted to be smaller than the tension of the biaxially stretched polypropylene film drawn from the first roll.

  Since this laminated film has the property that it is easier to stretch than the OPP film, if a tension equivalent to that of the OPP film is applied to the laminated film, shrinkage occurs when released from the tension, and the produced packaging bag becomes It will be warped.

  Therefore, by making the tension applied to the laminated film in advance smaller than that of the OPP film, the shrinkage of the laminated film that occurs when released from the tension can be made equivalent to that of the OPP film. Can be prevented.

Further, it is desirable that the OPP film and the laminated film can transmit a predetermined amount of oxygen. That is, for OPP films, the oxygen permeability at 20 ° C. is 1000 to 3750 cc / m ² · day · atm, more preferably 1200 to 1800 cc / m ² · day · atm, and for laminated films, 20 ° C. It is preferable that the oxygen permeation rate is 2500 to 20000 cc / m ² · day · atm, more preferably 4000 to 15000 cc / m ² · day · atm.

By using a film having oxygen permeability such as these, a packaging bag that can keep the freshness of vegetables and fruits good can be made. In addition, by making the oxygen permeability of the laminated film in the range of 4000-15000cc / m ² · day · atm, make packaging bags that can keep freshness for many fruits and vegetables Can do it.

  In addition, since the thickness of the film affects the processability when making a packaging bag, it is 8 to 30 μm, preferably 10 to 25 μm, more preferably 15 to 25 μm, and low-density high-pressure polyethylene for an OPP film. It is 12 to 44 μm for a laminated film with a three-layer structure in which layers are sandwiched with polypropylene layers, and 11 to 37 μm for a laminated film with a two-layer structure having a low-density high-pressure polyethylene layer and a polypropylene layer. good.

  In particular, the thickness of each layer constituting the laminated film is preferably 10 to 30 μm for the low-density high-pressure polyethylene layer and 1 to 7 μm for the polypropylene layer.

  By using a film having such a thickness, a packaging bag that can maintain good freshness of vegetables and fruits can be produced.

  In addition, because fruits and vegetables such as vegetables and fruits have different breathing rates and deterioration rates depending on the variety, harvest time, production area, distribution conditions, storage conditions, and sales conditions, for example, the thickness of the film can be reduced for vegetable packaging bags and fruits. You may make it change with a packaging bag.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a flow showing a manufacturing process of an embodiment according to the present invention. In the method for manufacturing a packaging bag according to the present invention, the tension adjusting step (step S1), the overlapping step (step S2), the bottom portion forming step (step S3), the side portion forming step (step S4), the conveying step (step S5), Bag making is performed through six processes including a storage process (step S6).

  FIG. 2 is an explanatory view schematically showing a bag making machine A for producing a packaging bag according to the present invention. The bag making machine A is provided with a first roll 11 wound with an OPP film 19 and a second roll 12 wound with a laminated film 20, and the OPP film 19 drawn from the rolls 11 and 12, The laminated bag 20 is superposed and thermally melted to produce the packaging bag 18 in a so-called two-fold process. In the following, description will be given in order along the flow shown in FIG. The laminated film used here has a thickness of 25 μm in which a low-density high-pressure polyethylene layer having a thickness of 15 μm is formed in a sandwich shape with a polypropylene layer having a thickness of 5 μm.

[Tension adjustment process]
First, in the tension adjustment step, a predetermined tension is applied to the OPP film 19 and the laminated film 20 drawn from the rolls 11 and 12, so that the bag 18 is not warped when the bag is made ( Step S1).

  The OPP film 19 pulled out from the first roll 11 includes a first guide roller 30, a second guide roller 31, and a first tension roller 13 disposed below the first and second guide rollers 30, 31. , Respectively.

  The first tension roller 13 is a moving pulley-like roller that can move in the vertical direction. The tension of the first tension roller 13 is pushed downward by a tension adjusting device (not shown) to apply tension to the OPP film 19. I try to put it on.

  On the other hand, similarly to the first roll, the laminated film 20 drawn from the second roll 12 is below the third guide roller 32, the fourth guide roller 33, and the third and fourth guide rollers 32, 33. Are respectively wound around the second tension roller 14 disposed on the belt.

  The second tension roller 14 is also a moving pulley-like roller that is movable in the vertical direction. By pressing the shaft of the second tension roller 14 downward by a tension adjusting device (not shown), the laminated film 20 The tension is applied to the.

  Here, the tension applied to the laminated film 20 by the second tension roller is about one half of the tension applied to the OPP film by the first tension roller 13. However, it is a matter of course that these tensions are appropriately adjusted according to the temperature of the film and the humidity during production.

  Thereby, the difference in shrinkage caused by the difference in the film material is corrected to prevent warping of the packaging bag after bag making.

  Each tension roller 13, 14 can weaken the tension applied to each film 19, 20 by moving the shaft upward.

  In this embodiment, the tension is adjusted by one guide roller and one tension roller for one film, but the present invention is not limited to this, and the buffer area of the film during the flow operation Therefore, more guide rollers and a plurality of tension rollers may be provided.

[Stacking process]
Next, the OPP film 19 and the laminated film 20 that have undergone the tension adjusting step are conveyed to the overlapping step. In this overlapping step, the films are overlapped with each other while maintaining the tension applied thereto to form a double film 21. (Step S2).

  That is, the OPP film 19 that has passed through the second guide roller 31 is wound around the fifth guide roller 34, the laminated film 20 that has passed through the fourth guide roller 33 is wound around the sixth guide roller 35, and the other film is applied to one film. Are brought into contact with each other to form a double film 21.

  Note that the laminated film 20 used in this embodiment is a low-density high-pressure polyethylene layer formed in a sandwich with a polypropylene layer, so when the double film 21 is formed, the laminated film 20 facing the OPP film 19 is used. The layer is naturally a polypropylene layer, but even when the laminated film 20 has a two-layer structure of a low-density high-pressure polyethylene layer and a polypropylene layer, the layer of the laminated film 20 facing the OPP film 19 is a polypropylene layer. Is preferred.

  That is, when the laminated film 20 has a two-layer structure of a low-density high-pressure polyethylene layer and a polypropylene layer, the double film 21 is formed with the polypropylene layer facing the OPP film 19.

  By doing in this way, a welding part with high intensity | strength can be formed in the bottom part formation process (step S3) and the side part formation process (step S4) mentioned later.

  A seventh guide roller 36 and a pressing roller 37 are disposed downstream of the fourth guide roller 33 and the sixth guide roller 35, and a gap between the seventh guide roller 36 and the pressing roller 37 is provided. By sandwiching the double film 21, the tension of the film is maintained.

  Therefore, the double film 21 can be formed while maintaining the tension applied to each film in the tension adjusting step.

[Bottom forming process]
Next, a bottom portion forming step is performed in which the substantially central portion in the width direction of the double film 21 formed in the overlapping step is continuously melted to form the bottom portion 41 (step S3).

  FIG. 3 shows a state in which the double film 21 in the bottom forming step is viewed from the front, and the temperature is set at approximately 340 to 400 ° C. at the substantially central portion in the width direction of the double film 21 indicated by reference numeral B in the drawing. At the same time, the bottom forming hot blade 15 was brought into contact and melted, and at the same time, the end of the OPP film 19 and the end of the laminated film 20 were welded along the length direction of the double film 21. A bottom 41 is formed. In FIG. 3, white arrows indicate the direction in which the double film 21 flows.

  Here, the bottom forming hot blade 15 may be anything that is generally used as a hot blade for bag making, and is particularly limited as long as the end portion can be welded while cutting the double film 21. It is not something.

(Side formation process)
Next, the double film 21 having the bottom 41 formed in the bottom forming step is heat-cut in the width direction to form a side portion to form a bag (step S4).

  In this side portion forming step, as shown in FIG. 2, a side portion forming hot blade 16 that can be moved up and down at predetermined time intervals on the upper portion of a roll conveyor 17 in which a plurality of rolls are arranged in parallel. The double film 21 that has undergone the bottom forming process is passed through the gap between the roll conveyor 17 and the side forming hot blade 16, and the side forming hot blade 16 is moved up and down at a predetermined time interval. When the sheet is moved downward, the double film 21 is brought into contact with the double film 21 to be melted and melted to form a side portion 42 in a direction intersecting with the bottom portion 41 as shown by a broken line in FIG. I am doing so. In addition, the white arrow in FIG. 4 indicates the direction in which the double film 21 flows.

  The time interval of the vertical movement of the side forming hot blade 16 can be adjusted as appropriate according to the size of the packaging bag 18 to be manufactured.By increasing the time interval of the vertical movement, the internal volume is increased. By shortening the time interval, the packaging bag 18 having a small internal volume can be manufactured.

  Here, the side forming hot blade 16 is brought into contact from the film side having the high melting point of the double film 21, that is, from the OPP film 19 side in this embodiment. Moreover, the laminated film 20 is disposed with the polypropylene layer facing the OPP film 19.

  That is, first, the OPP film 19 having a high melting point is melted and cut, and the melted OPP film 19 is entangled with a laminated film 20 in which a low-density high-pressure polyethylene layer is formed in a sandwich shape with a polypropylene layer. As shown in the enlarged cross-sectional view of the welded portion of the side portion 42, the seal ball 43 is formed on the side portion 42. Therefore, when the seal balls 43 are cooled and solidified, the side portions 42 having sufficient strength can be formed while the packaging bag 18 is composed of the OPP film 19 and the laminated film 20 having different melting points. In the figure, reference numeral 22 indicates a polypropylene layer (CCP), and reference numeral 23 indicates a low-density high-pressure polyethylene layer. For convenience of explanation, the thickness of each layer is exaggerated and is not necessarily accurate.

  Further, even when the laminated film 20 has a two-layer structure having a low-density high-pressure polyethylene layer and a polypropylene layer, similarly, as shown in FIG. 5B, an enlarged cross-sectional view of the welded portion of the side portion 42. As shown, the seal ball 43 is formed on the side portion 42. Therefore, when the seal balls 43 are cooled and solidified, the side portions 42 having sufficient strength can be formed while the packaging bag 18 is composed of the OPP film 19 and the laminated film 20 having different melting points.

  If the laminated film 20 having a low melting point is first brought into contact with the side forming hot blade 16, excessive heat is applied to the laminated film 20 at the fusing part, as shown in FIG. 5 (c). Further, there is a possibility that a cracking phenomenon occurs in the root portion of the seal ball 43, and a blocking phenomenon occurs in which the strength of the side portion 42 becomes extremely weak.

  If this blocking phenomenon occurs, a hole is formed in the packaging bag 18 from the crack 44 where the film has become thin, or tearing occurs when fruits and vegetables are stored in the packaging bag 18, which is not preferable.

  Therefore, in order to prevent the blocking phenomenon, it is preferable that the side forming hot blade 16 is first brought into contact with the OPP film 19 having a high melting point.

  The temperature of the side forming hot blade 16 is adjusted to 360 to 420 ° C. Accordingly, the seal balls 43 that can maintain sufficient strength can be formed on the side portions 42, and the packaging bag 18 can be efficiently manufactured.

[Conveyance process]
Next, a transporting process is performed in which the packaging bag 18 formed in the side part forming process is placed on the roll conveyor 17 and transported to the storage part 6 provided at the terminal part of the roll conveyor 17 (step S5). ).

  Incidentally, in the side part forming step, the laminated film 20 side of the double film 21 is faced down, and the side part forming hot blade 16 is brought into contact with the OPP film side without having to invert the formed packaging bag 18, Since it can be transported as it is by the roll conveyor 17 in this transport process, the labor required for reversal can be reduced, and the production cost can be reduced.

[Storage process]
And the storage process which piles up the packaging bag 18 sent through the conveyance process and stores it in the storage part 6 is performed (step S6).

  In this storage step, the packaging bag 18 may be stored in the storage unit 6 manually, or a bundle of the packaging bags 18 may be mechanically formed and stored in the storage unit 6.

  As shown in FIG. 6, the packaging bag 18 stored in this manner is composed of an OPP film 19 and a laminated film 20, and has a welded bottom portion 41 and side portions 42 and 42, and an opening 45 formed in the upper portion. And a bag body.

  As described above, according to the present invention, even if fruits and vegetables are sealed, the oxygen and carbon dioxide concentrations in the bag can be maintained at suitable values, while excellent economic efficiency and It is possible to provide a method for manufacturing a packaging bag having transparency, heat-weldability, and appearance, and a packaging bag manufactured by the method.

  Finally, the description of each embodiment described above is an example of the present invention, and the present invention is not limited to the above-described embodiment. For this reason, it is a matter of course that various modifications can be made in accordance with the design and the like as long as they do not depart from the technical idea according to the present invention other than the embodiments described above. That is, the manufacturing method of the packaging bag 18 according to the present embodiment and the packaging bag 18 manufactured by the method have been described so far with reference to the drawings, but can be appropriately changed without departing from the concept of the present invention. Needless to say.

  For example, in this embodiment, the bottom portion 41 is formed by fusing the substantially central portion in the width direction of the double film 21, and the side forming hot blade 16 contacts the double film 21 once in the subsequent side portion forming step. Although the manufacturing method by what is called two picking which can obtain the two packaging bags 18 by this was demonstrated, it is not limited to this, It can apply also to the manufacturing method by one picking.

  Further, in the bottom forming step, the bottom forming hot blade 15 is continuously brought into contact with the double film 21 to form the bottom 41. However, the present invention is not limited to this, and is similar to the side forming hot blade 16. The bottom 41 may be formed by heat welding using the above method.

  Further, the packaging bag 18 manufactured in the present embodiment is a substantially rectangular bag body, but is not limited to this, and the substantially trapezoidal bag body and the side portion 42 also serve as the bottom portion 41. It may be triangular. As an example, the packaging bag 18 having these shapes may be provided with a plurality of side-forming hot blades 16 in a substantially eight-letter shape, or by changing the angle with respect to the flow direction of the double film 21. Can be manufactured.

  In addition, the thickness of the OPP film and laminated film can be changed according to the variety of vegetables and fruits stored in the packaging bag, the production area, the harvest time, etc. Because the breathing rate differs from winter, the film thickness is changed between a summer packaging bag for storing vegetables harvested in summer and a winter packaging bag for storing vegetables harvested in winter. You may do it.

It is the flow which showed the process of the manufacturing method of the packaging bag which concerns on this invention. It is explanatory drawing which showed the bag making machine for manufacturing the packaging bag which concerns on this invention. It is explanatory drawing which showed the double film in a bottom part formation process. It is explanatory drawing which showed the double film in a side part formation process. It is an expanded sectional view of the side part formed in the side part formation process. It is explanatory drawing which shows the packaging bag manufactured with the manufacturing method of the packaging bag which concerns on this invention.

Explanation of symbols

11 First roll
12 Second roll
18 Packaging bag
19 Biaxially oriented polypropylene film
20 Laminated film
S2 Overlay process
S3 Bottom forming process
S4 Side forming process

Claims (5)

A first roll wound with a biaxially stretched polypropylene film having a thickness of 8 to 30 μm and an oxygen permeability at 20 ° C. of 1000 to 3750 cc / m ² · day · atm, and a thickness of 12 to 44 μm and oxygen permeability at 20 ° C. is used and a second roll wound laminated film is ^{2500~20000cc / m 2 · day · atm} , and the laminated film and the biaxially oriented polypropylene film was thermally fused while a method for producing freshness retaining packaging bag for fresh produce to bag manufacturing by welding the ends,
The laminated film is a low-density high-pressure polyethylene layer having a thickness of 10 to 30 μm formed as a sandwich with a polypropylene layer having a thickness of 1 to 7 μm ,
A biaxially oriented polypropylene film drawn out from the first roll, and a laminated film drawn from said second roll, the overlapping step of overlapping while conveying respectively,
A bottom forming step of sealing the film while transporting the stacked films in a predetermined direction while thermally fusing along the predetermined direction;
In a direction crossing the forming direction of the bottom formed in the bottom forming step, a hot blade is brought into contact with the biaxially stretched polypropylene film side and the melted biaxially stretched polypropylene film is entangled with the laminated film. a bag forming step of sealing to form a side to the film a bag shape Te,
A method for producing a packaging bag for maintaining freshness of fruits and vegetables . A first roll wound with a biaxially stretched polypropylene film having a thickness of 8 to 30 μm and an oxygen permeability at 20 ° C. of 1000 to 3750 cc / m ² · day · atm, and a thickness of 11 to 37 μm and oxygen permeability at 20 ° C. is used and a second roll wound laminated film is ^{2500~20000cc / m 2 · day · atm} , and the laminated film and the biaxially oriented polypropylene film was thermally fused while a method for producing freshness retaining packaging bag for fresh produce to bag manufacturing by welding the ends,
The laminated film has a low-density high-pressure polyethylene layer having a thickness of 10 to 30 μm and a polypropylene layer having a thickness of 1 to 7 μm .
The biaxially oriented polypropylene film drawn out from the first roll, so as to oppose the surface of the polypropylene layer of the laminate film drawn from said second roll, the overlapping step of overlapping while conveying respectively,
A bottom forming step of sealing the film while transporting the stacked films in a predetermined direction while thermally fusing along the predetermined direction;
In a direction crossing the forming direction of the bottom formed in the bottom forming step, a hot blade is brought into contact with the biaxially stretched polypropylene film side and the melted biaxially stretched polypropylene film is entangled with the laminated film. a bag forming step of sealing to form a side to the film a bag shape Te,
A method for producing a packaging bag for maintaining freshness of fruits and vegetables . In the bottom portion forming step, the ends are welded while fusing at a temperature of 3 40 to 400 ° C.,
In the bag forming process, 3 60-420 claim 1 or claim 2 method of manufacturing fruit and vegetable freshness packaging bag according to the ends while fusing at a temperature of ℃ characterized welded to Rukoto. And in the bottom portion forming step, the tension of the biaxially oriented polypropylene film drawn out from the first roll, claim 1 any one of being greater than the tension of the laminate film pulled out from the second roll The manufacturing method of the packaging bag for freshness preservation of fruit and vegetables as described in 2. A freshness-keeping packaging bag for fruits and vegetables produced by the method for producing a freshness-keeping packaging bag for fruits and vegetables according to any one of claims 1 to 4 .

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