JP7849985B2 - Apparatus and method for manufacturing packaging bags - Google Patents

Description

This invention relates to a manufacturing apparatus and method for packaging bags.

In conventional packaging bags, the composite film used for the body and bottom components has a layer of heat-adhesive resin (sealant), such as polyethylene (PE), laminated on the inner surface, and a base material, such as polyethylene terephthalate (PET), which has higher heat resistance than the sealant, laminated on the outer surface. When heat-bonding the body components together, or between the body and bottom components, the sealant is melted to join the inner surfaces of the composite film. However, packaging bags containing different types of resins present a problem in that they are difficult to recycle as plastic containers and packaging.

Patent Document 1 addresses the challenge of stably manufacturing packaging bags with high dimensional accuracy, even when using inexpensive polyethylene resin film that is prone to thermoplastic deformation as the base film. It proposes interposing a protective film between the base film and the sealing member and then heat-sealing them.

Patent No. 4536457

In recent years, monomaterial packaging using a single resin has been advocated to facilitate recycling. However, when forming packaging bags such as standing pouches from a film made of a single resin, adhesion (blocking) can occur where the outer surfaces of the films overlap when joining (sealing) the inner surfaces of the films. When blocking occurs, it can be difficult to open the overlapping films when filling the packaging bag with contents. To suppress blocking, joining the films at a lower processing temperature increases processing time, leading to decreased productivity.

Paragraph 0023 of Patent Document 1 discloses inserting a cooling plate to prevent welding on the side where the bottom film is folded. However, using a cooling plate through which cooling water flows may increase costs and complicate management.

This invention has been made in view of the above circumstances, and aims to provide a packaging bag manufacturing apparatus and manufacturing method that can achieve blocking prevention at a lower cost and facilitate production management.

To solve the aforementioned problems, the present invention provides a packaging bag manufacturing apparatus having a folded portion between the main surfaces of the body, wherein the apparatus comprises: a conveying means for conveying the packaging film forming the body in the longitudinal direction; a joining means for joining the main surface of the body and the folded portion by heat welding; and a blocking prevention member inserted inside the folded portion in at least the section of the packaging film in the longitudinal direction including the joining means, wherein the blocking prevention member is a molded resin body.

The body portion is formed by sandwiching a folded film, which is folded in half along a fold line, between body films that form the main surface of the body portion, and the manufacturing apparatus may include an insertion means for inserting the folded film between the body films.
The blocking prevention member may remain stationary in the longitudinal direction while the packaging film is being transported in the longitudinal direction.
The blocking prevention member may be a film or sheet made of a resin selected from polyester resins, polyamide resins, and fluororesins.
The downstream side of the joining means may be provided with a sealing means for sealing the periphery of the packaging bag, and the blocking prevention member may be positioned upstream of the sealing means.

Furthermore, the present invention provides a method for manufacturing a packaging bag having a folded portion between the main surfaces of the body, comprising: a conveying step of conveying the packaging film forming the body in the longitudinal direction; and a joining step of joining the main surface of the body and the folded portion by heat welding; wherein a blocking prevention member is inserted inside the folded portion in at least the section of the packaging film in the longitudinal direction that includes the location where the joining step is performed, and the blocking prevention member is a molded resin body.

The body portion is formed by sandwiching a folded film, which is folded in half along a fold line, between body films that form the main surface of the body portion, and the method may include an insertion step of inserting the folded film between the body films prior to the joining step.
The packaging film is a laminated film having a sealant and a substrate, and the difference in melting points between the sealant and the substrate of the packaging film may be 0 to 100°C.
The folded portion may have a polyethylene-based resin on its outer surface.
The packaging film may be a laminated film having a sealant and a substrate made of polyethylene resin.
The packaging film is a laminated film having a sealant and a substrate, and the sealant and substrate of the packaging film may be the same type of resin belonging to any one selected from polyethylene (PE), ethylene-vinyl acetate copolymer (EVA), and polypropylene (PP).

According to the present invention, it is possible to provide a manufacturing apparatus and method for packaging bags that can achieve blocking prevention at a lower cost and facilitate production management.

This is a perspective view illustrating an apparatus for manufacturing packaging bags according to an embodiment. This is a cross-sectional view illustrating an anti-blocking member inserted into the folded portion. This is a cross-sectional view illustrating the structure of the bottom of a packaging bag. This is a cross-sectional view showing an example where the folded portion is formed from one of the main surfaces of the body. This is a cross-sectional view showing an example where the folded portion is continuous with both main surfaces of the body.

The present invention will be described below with reference to the drawings, based on preferred embodiments.
Figure 1 is a perspective view illustrating a packaging bag manufacturing apparatus according to an embodiment. Figure 2 is a cross-sectional view illustrating a blocking prevention member inserted into the folding portion. Figure 3 is a cross-sectional view illustrating the structure of the bottom of the packaging bag. In the following description, the packaging bag manufacturing apparatus (bag making machine) may be simply referred to as the manufacturing apparatus 10.

As shown in Figure 1, the manufacturing apparatus 10 of this embodiment can manufacture a packaging bag 4 having a bottom portion 4a with a folded portion 3 formed between the main surfaces of the body. As will be described in detail later, the blocking prevention member 21 of the manufacturing apparatus 10 is inserted inside the folded portion 3, as shown in Figure 2. The packaging bag 4 has a folded portion 3, folded along a fold line 3c, between the main surfaces 2 of the body.

As shown in Figure 3, at the bottom 4a of the packaging bag 4, a folded portion 3 is formed between the pair of main surfaces 2 by a fold line 3c. The packaging bag 4 in the illustrated example is a standing pouch. In this case, the folded portion 3 is the bottom film of the packaging bag 4.

In the manufacturing apparatus 10 shown in Figure 1, the main surface 2 of the body and the folded portion 3 are formed from separate films. In this case, the main surface 2 of the body is also called the body film, and the folded portion 3 is also called the folded film. In the following explanation, the films forming the main surface 2 of the body and the folded portion 3 are sometimes collectively referred to as packaging films 2 and 3. Packaging films 2 and 3 are films supplied to the manufacturing apparatus 10 as materials for the packaging bag 4.

The packaging films 2 and 3 may each be laminated films having at least sealants 2a and 3a and base materials 2b and 3b, or at least one of the packaging films 2 and 3 may be a single-layer film. The packaging films 2 and 3 may also be resin films mainly composed of polyethylene resin. For example, the base materials 2b and 3b and the sealants 2a and 3a may be polyethylene resin or the like.

When packaging films 2 and 3 have sealants 2a and 3a, the folded portion 3 is joined to the main surface 2 at the bottom 4a of the packaging bag 4 by heat-sealing the sealants 2a and 3a facing each other. Similarly, at the sides 4b of the packaging bag 4, the pair of main surfaces 2 are sealed together by heat-sealing the sealants 2a facing each other. If packaging films 2 and 3 are single-layer films, it does not matter which side is facing each other during heat-sealing.

In the manufacturing apparatus 10 shown in Figure 1, the main surface 2 of the body is arranged in a manner that connects to the longitudinal direction 5. In Figure 1, the longitudinal direction 5 of the main surface 2 is the left-right direction. When the body of the packaging bag 4 has a pair of main surfaces 2, the pair of main surfaces 2 can be formed from the same raw film roll 1.

The base film 1 has approximately twice the width of the main surface 2, and is cut to approximately half its width by the bifoliation means 12 to form a pair of main surfaces 2. Although not specifically shown, the base film 1 is supplied from a reel wound in a roll shape. Furthermore, the pair of main surfaces 2 may each be formed from different base films 1.

In the biplane formation mechanism 12, a pair of main surfaces 2 are conveyed with a gap between them in the vertical direction, and then the upper and lower main surfaces 2 are positioned to overlap using the alignment roll 12a. The main surface 2 downstream of the biplane formation mechanism 12 is intermittently driven by the conveying mechanisms 13 and 18.

The illustrated manufacturing apparatus 10 comprises a first conveying means 13 installed upstream of the joining means 15, and a second conveying means 18 installed downstream of the sealing means 16. Examples of conveying means 13 and 18 include devices that drive the main surface 2 by clamping it between rolls, and devices that intermittently move a gripping tool clamping the main surface 2 over a certain distance using an air cylinder or the like.

The joining means 15 is a device that heat-seals the bottom 4a of the packaging bag 4 by heating with a heater 15a and then cooling with a cooling unit 15b. Similarly, the sealing means 16 is a device that heat-seals both sides 4b of the packaging bag 4 by heating with a heater 16a and then cooling with a cooling unit 16b.

In the section including the joining means 15 and the sealing means 16, the packaging films 2 and 3 are intermittently driven by the conveying means 13 and 18. This allows for a temporary halt in the feeding of the packaging films 2 and 3 when the heaters 15a and 16a heat them, and when the cooling units 15b and 16b cool them. The feed rate (pitch) of the intermittently fed packaging films 2 and 3 may be adjusted according to the dimensions of the packaging bag 4.

Examples of heaters 15a and 16a include devices having molds such as heating plates. Examples of cooling units 15b and 16b include devices having molds such as cooling plates. These molds may be placed on both sides of the overlapping packaging films 2 and 3. When heating or cooling the packaging films 2 and 3 using the molds, the packaging films 2 and 3 may be pressed. Temporarily stopping the feeding of the packaging films 2 and 3 during heat sealing can stabilize dimensional accuracy.

Similar to bag-making and filling machines using flat bags, it is also possible to heat-seal the bottom 4a and sides 4b of the packaging bag 4 while continuously transporting the packaging films 2 and 3. As a mold for heating or cooling the packaging films 2 and 3 during continuous transport, a roll with pressing sections for the packaging films 2 and 3 formed at predetermined intervals in the circumferential direction can be used.

Although not specifically shown in the illustrations, it is also possible to heat-seal the top of the packaging bag 4 to form a spout or the like. Two or more types of sealing means 16 may be provided to heat-seal the periphery of the packaging bag 4 before it is separated from the packaging films 2 and 3. These sealing means 16 may be positioned downstream of the joining means 15.

The packaging bag 4, with its bottom 4a and sides 4b heat-sealed, is separated from the packaging film 2 and 3 by a cutting means 17. The cutting means 17 is not particularly limited, but an example is a guillotine cutter. If a spout or the like is formed at the top of the packaging bag 4, the area around the spout or the like may be trimmed. In the illustrated example, the packaging bags 4 are separated from the packaging film 2 and 3 one by one. Although not specifically shown, it is also possible to separate the packaging bags 4 from the packaging film 2 and 3 while they remain connected by cutting the packaging film 2 and 3 in the width direction 6 each time several packaging bags 4 pass through the cutting means 17.

The manufacturing apparatus 10 of this embodiment includes an insertion means 14 for inserting the folded portion 3 as a separate film between a pair of main surfaces 2. When the pair of main surfaces 2 overlap from above and below, the folded portion 3 is inserted between these main surfaces 2. The folded portion 3 may be conveyed along the longitudinal direction 5 from a position upstream of the point where the main surfaces 2 overlap.

The insertion means 14 may supply a tape-like film 3d without fold lines 3c from a reel wound in a roll shape. In this case, the folded portion 3 with fold lines 3c is formed by folding the tape-like film 3d into a V-shape using a molding plate or the like (not shown).

A roll member 13a is installed at the point where the folded portion 3 is inserted between the main surfaces 2. The roll member 13a grips the main surfaces 2 approaching from above and below the folded portion 3, changing the transport direction of the main surfaces 2 to the longitudinal direction 5. Between the roll member 13a and the cutting means 17, the folded portion 3 is transported overlapping the main surfaces 2 and connected to the longitudinal direction 5.

The alignment rolls 12a deflect the conveying direction so that the front-to-back and left-to-right positions of the upper and lower main surfaces 2 are precisely aligned. These alignment rolls 12a are movable in the vertical direction (the direction of overlapping the main surfaces 2) and in the width direction 6 of the main surfaces 2 by a servo motor (not shown). In Figure 1, the width direction 6 of the main surfaces 2 is from front to back.

The operation of the servo motor that moves the alignment roll 12a is controlled by optical sensors (not shown) that detect the pitch printing pattern and the positions of both ends in the width direction 6 of the main surface 2, respectively, and by control means (not shown) that detect the positional displacement of the main surface 2 based on the output values of these optical sensors. For example, a photocell or a CCD camera can be used as the optical sensor.

The bifloating mechanism 12 may include a buffer mechanism 11 that forms a variable-amount buffer on the main surface 2. The buffer mechanism 11 can absorb delays or excesses in the feed of the main surface 2 that occur when converting the continuous feed upstream to the intermittent feed downstream. Upstream of the buffer mechanism 11, the main surface 2, including the raw film 1, is supplied via continuous feed. Although not specifically shown, the buffer mechanism 11 can be omitted when the main surface 2, including the raw film 1, is supplied via intermittent feed.

In the illustrated example of the manufacturing apparatus 10, for the sake of simplifying the illustration, an insertion means 14 is installed to insert the folded portion 3 into one side of the width direction 6 of the main surface 2 (the front side in Figure 1). Furthermore, a blocking prevention member 21 is inserted inside the folded portion 3.

When packaging bags 4 are arranged in two rows in the width direction 6 (double-sided cutting), insertion means 14 are positioned on both sides of the width direction 6, and the folded portions 3 are inserted on both sides of the width direction 6 of the main surface 2. When double-sided cutting is performed, blocking prevention members 21 and joining means 15 are installed on both sides of the width direction 6. Furthermore, when separating the two rows of manufactured packaging bags 4, a cutter (not shown) is provided to cut the main surface 2 along the longitudinal direction 5 at the center of the width direction 6.

Before overlapping the folded portion 3 with the main surface 2, punch holes (not shown) are formed through the folded portion 3 using the punching means 14a. This allows the pair of main surfaces 2 to face each other through the punch holes in the folded portion 3, enabling heat welding. It is preferable that the punching means 14a forms the punch holes after the fold line 3c is formed in the folded portion 3. This suppresses misalignment of the punch holes, which are positioned symmetrically across the fold line 3c.

In the manufacturing apparatus 10 of this embodiment, as shown in Figure 2, when joining the folded portion 3 to the main surface 2 by heat welding using the joining means 15, the blocking prevention member 21 is inserted inside the folded portion 3, which is folded in half along the fold line 3c. This interposes the blocking prevention member 21 between the overlapping outer surfaces of the folded portion 3, preventing adhesion (blocking).

If the material forming the outer surface of the folded portion 3, for example, the base material 3b, is a resin with a relatively low melting point, such as a polyethylene resin, then when heated by the heater 15a of the joining means 15, at least a portion of the base material 3b on the outer surface may melt or soften, resulting in adhesion. When the folded portion 3 is cooled by the cooling unit 15b, the adhesion of the folded portion 3 is reduced, but adhesion may persist in the section from the heater 15a to the cooling unit 15b. In the manufacturing apparatus 10 of this embodiment, a blocking prevention member 21 is inserted at the location where the outer surfaces of the folded portions 3 overlap, thereby suppressing adhesion between the outer surfaces of the folded portions 3.

The blocking prevention member 21 is positioned in the longitudinal direction of the packaging films 2 and 3, at least in the section including the joining means 15. In this embodiment, the blocking prevention member 21 is a molded resin body. This allows for blocking prevention of the folded portion 3 at a lower cost than a cooling plate through which cooling water flows, and simplifies production management.

The blocking prevention member 21 is preferably formed from a resin such as a polyester resin, polyamide resin, or fluororesin. Examples of polyester resins include polyethylene terephthalate (PET). Examples of polyamide resins include nylon (Ny). Examples of fluororesins include polytetrafluoroethylene (PTFE). The blocking prevention member 21 is preferably formed from a resin with a higher melting point than the resin used in the folded portion 3, and also preferably from a resin with a higher melting point than the resin used in the main surface 2.

The blocking prevention member 21 may be a sheet obtained by coating or impregnating a separate substrate with the high-melting-point resin mentioned above. For example, using glass cloth or inorganic fiber material as the substrate for the blocking prevention member 21 can increase the strength of the sheet and reduce the frequency of replacement of the blocking prevention member 21.

While it is conceivable to use a metal anti-blocking member 21, a metal plate would be too thick, and a metal foil would have low mechanical strength. By using a resin molded body as the anti-blocking member 21, sufficient strength and durability can be achieved even with a small thickness. Furthermore, even if the resin anti-blocking member 21 comes into contact with the packaging films 2 and 3, it is less likely to damage them.

The thickness of the blocking prevention member 21 is not particularly limited, but may be any appropriate thickness such as a resin film, resin sheet, or resin board, for example, about 10 μm to 1 mm. If the blocking prevention member 21 is a film or sheet, insertion into the folded portion 3 becomes easier, which is preferable. Furthermore, if the blocking prevention member 21 is thin, gaps are less likely to form around the fold line 3c of the folded portion 3, which can suppress wrinkles in the packaging films 2 and 3.

As a countermeasure against blocking in the joining means 15, it is conceivable to provide a heat-resistant material or coating layer on the outer surface of the folded portion 3, but this would require changing the material of the packaging bag 4, increasing costs. If the blocking prevention member 21 is provided in the manufacturing apparatus 10, there is no need to implement countermeasures on the packaging film 2 and 3 side, thus simplifying quality control.

While the folded portion 3 is being transported overlapping with the main surface 2, the blocking prevention member 21 may remain stationary in the longitudinal direction 5. If the blocking prevention member 21 is formed from a resin with a higher melting point than the folded portion 3, the folded portion 3 is less likely to weld to the blocking prevention member 21, allowing the folded portion 3 to be transported smoothly along the surface of the blocking prevention member 21.

In the illustrated example, the blocking prevention member 21 is supported by a support member 22 such as a bar or plate, constituting the blocking prevention means 20. It is preferable that the support member 22 is positioned in a portion of the longitudinal direction 5 of the blocking prevention member 21. In the locations where the heater 15a and cooling section 15b of the joining means 15 are positioned, it is preferable that only the blocking prevention member 21 is inserted between the folded sections 3, without the support member 22 being positioned.

To suppress wrinkles in the blocking prevention member 21, support members 22 may be placed at both ends of the blocking prevention member 21 and pulled in the longitudinal direction 5 to apply tension to the blocking prevention member 21. If the support members 22 do not move in the longitudinal direction 5, the blocking prevention member 21 may be fixed to the support members 22 while being pulled so that tension is applied.

The support member 22 can be moved in the width direction 6 by a driving means (not shown) such as a cylinder or ball screw. During the manufacturing process of the packaging bag 4 (while the manufacturing apparatus 10 is running), the blocking prevention member 21 does not need to be moved in the longitudinal direction 5, but the folded portion 3 may be pressed in the direction in which the fold line 3c protrudes.

When placing the packaging films 2 and 3 onto the manufacturing apparatus 10 before starting the manufacturing process for the packaging bag 4, the blocking prevention member 21 may be inserted into a predetermined position relative to the folding portion 3. Furthermore, for example, during maintenance work such as inspection and cleaning of the joining means 15, the blocking prevention member 21 may be retracted from the position of the joining means 15.

The positions of both ends of the blocking prevention member 21 are not particularly limited, but it is preferable that the upstream end of the blocking prevention member 21 be downstream of the drilling means 14a. The blocking prevention member 21 may also be positioned where it is sandwiched between the roll member 13a, or it may be positioned downstream of the roll member 13a. It is preferable that the downstream end of the blocking prevention member 21 be upstream of the sealing means 16.

If the blocking prevention member 21 is positioned upstream of the sealing means 16, the main surface 2, including the area where punch holes are formed in the folded portion 3 by the perforating means 14a, may be heat-welded when the sealing means 16 seals the side portion 4b of the packaging bag 4. Although not specifically shown, a notch or the like may be provided in a part of the blocking prevention member 21, and the area where punch holes are formed in the folded portion 3 may be heat-welded by the joining means 15.

If the material forming the outer layer in the thickness direction of the main surface 2, such as the base material 2b, is a resin with a relatively low melting point, such as a polyethylene resin, then when heated by the heater 16a of the sealing means 16, at least a portion of the base material 2b of the main surface 2 may melt or soften, resulting in adhesion. While the adhesion of the main surface 2 decreases when cooled by the cooling section 16b, adhesion may persist in the section between the heater 16a and the cooling section 16b. It is preferable to implement adhesion prevention measures at least in the area where the main surface 2 contacts the heater 16a.

The means for preventing adhesion to the main surface 2 in the sealing means 16 is not particularly limited, and known configurations may be adopted. For example, as described in Patent Document 1, a molded body such as a film or sheet may be placed between the heater 16a of the sealing means 16 and the main surface 2. The material of the means for preventing adhesion to the main surface 2 is not particularly limited, but examples include resins such as polyester resins, polyamide resins, and fluororesins.

As shown in Figure 4, the folded portion 3 may be formed by folding it from one of the main surfaces 2 of the body. Alternatively, as shown in Figure 5, the folded portion 3 may be continuous with both main surfaces 2 of the body and formed by folding the same film.

The manufacturing apparatus 10 of this embodiment is suitable for manufacturing packaging bags 4 made of a single material (monomaterial) mainly composed of polyethylene resin. In this case, the packaging films 2 and 3 used in the manufacture of the packaging bags 4 are films mainly composed of polyolefin resin. The packaging films 2 and 3 may also be laminated films having two or more polyolefin resin layers.

The polyolefin resin used in packaging films 2 and 3 is not particularly limited as long as it is a copolymer mainly composed of olefins, but examples include polyethylene resins and polypropylene resins. The packaging films 2 and 3 may also be laminated films having sealants 2a and 3a and base materials 2b and 3b made of polyethylene resin.

The polyethylene resin used in packaging films 2 and 3 may be a homopolymer of ethylene or a copolymer mainly composed of ethylene. Examples of monomers other than ethylene (comonomers) include one or more α-olefins such as 1-butene, 1-hexene, and 1-octene, cyclic olefins such as norbornene, and vinyl monomers such as vinyl acetate, vinyl chloride, and acrylic acid. The polyethylene resin may also be an ethylene-vinyl acetate copolymer (EVA), and if a monomer having an ester group, such as vinyl acetate, is copolymerized, some of the ester groups may be saponified, resulting in a copolymer containing vinyl alcohol.

The proportion of ethylene in the constituent monomers of the polyethylene resin is preferably 50% by weight or more, and may be, for example, 80 to 100% by weight. The ethylene or comonomer may be a compound derived from fossil resources such as petroleum, or a compound derived from biomass such as plants. The resin contained in the polyethylene resin layer may consist solely of polyethylene resin.

The polypropylene resin used in packaging films 2 and 3 may be a homopolymer of propylene (homoPP), or a random copolymer (randomPP) or block copolymer (blockPP) of propylene-ethylene copolymer, etc. Examples of monomers other than propylene (comonomers) include one or more α-olefins such as ethylene, 1-butene, 1-hexene, and 1-octene, and vinyl monomers such as vinyl acetate, vinyl chloride, and acrylic acid. When comonomers are used in the polypropylene resin, there may be one or more comonomers.

The proportion of propylene in the constituent monomers of the polypropylene resin is preferably 50% by weight or more, and may be, for example, 80 to 100% by weight. The propylene or comonomer may be a compound derived from fossil resources such as petroleum, or a compound derived from biomass such as plants. The resin contained in the polypropylene resin layer may consist solely of polypropylene resin.

The polyolefin resins used in the sealants 2a, 3a, and base materials 2b, 3b of the packaging films 2 and 3 may contain additives other than the resin itself. The additives are not particularly limited, but examples include antioxidants, lubricants, antiblocking agents, flame retardants, UV absorbers, light stabilizers, antistatic agents, colorants, and crosslinking agents. The additives may be components compatible with the resin or components incompatible with the resin.

At least a portion of the polyolefin resin used in packaging films 2 and 3 may include recycled resin. The recycled resin may be a chemically recycled resin, obtained by decomposing used resin into monomers such as ethylene and propylene, and then repolymerizing it. It may also be a mechanically recycled resin, obtained by regenerating used resin as a polymer through processes such as crushing and sorting. A mixture of recycled resin and new resin may also be used in the manufacture of packaging films 2 and 3.

The sealants 2a and 3a are arranged as the innermost layer on the inner surfaces of the packaging films 2 and 3. The sealant 2a on the main surface 2 can be used for joining the main surfaces 2 together, and for joining the main surfaces 2 to the folded portion 3. The sealant 3a on the folded portion 3 can be used for joining the main surface 2 to the folded portion 3.

The sealants 2a and 3a are preferably formed from polyethylene-based resins. Specific examples of materials for forming the sealants 2a and 3a include, for example, relatively low-density polyethylene-based resins such as linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE), and polypropylene-based resins.

The material forming sealants 2a and 3a may be a single polyolefin resin or a blend of two or more polyolefin resins. The resin contained in sealants 2a and 3a may be a polyolefin resin only, a polyethylene resin only, or a polypropylene resin only. The thickness of sealants 2a and 3a is not particularly limited, but for example, it may be approximately 60 to 180 μm.

The sealants 2a and 3a of the packaging films 2 and 3 may be single-layer sealant films or multi-layer sealant films. Multi-layer sealant films can be formed by laminating two or more layers of film-like sealant resin using methods such as co-extrusion, extrusion lamination, sandwich lamination, or heat lamination.

The base materials 2b and 3b are laminated on the outside in the thickness direction of the packaging film 2 and 3, beyond the sealants 2a and 3a. The base materials 2b and 3b may also be the outermost layers of the packaging film 2 and 3. Preferably, the base materials 2b and 3b can reinforce the mechanical strength of the packaging film 2 and 3 when the packaging film 2 and 3 are transported and used in the length direction. Compared to conventional laminates using PET film or the like as the base material, using packaging films 2 and 3 with polyethylene resin as the base materials 2b and 3b improves recyclability.

Specific examples of materials forming the base materials 2b and 3b include, for example, polyethylene resins with relatively low density such as linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE), as well as polyethylene resins with relatively high density such as medium-density polyethylene (MDPE) and high-density polyethylene (HDPE), and polypropylene resins.

The base materials 2b and 3b may be uniaxially or biaxially stretched resin layers, or unstretched resin layers. The material forming base materials 2b and 3b may be a single polyolefin resin, or a blend of two or more polyolefin resins. The resin contained in base materials 2b and 3b may be solely a polyolefin resin, solely a polyethylene resin, or solely a polypropylene resin. The thickness of base materials 2b and 3b is not particularly limited, but for example, it may be approximately 10 to 50 μm.

In conventional bag-making machines, the difference in melting points between the sealant and the base material is large (the melting point of the base material is significantly higher than that of the sealant). However, according to this embodiment, even when the difference in melting points between the sealants 2a, 3a and the base materials 2b, 3b of the packaging films 2, 3 is small (the melting points of the base materials 2b, 3b are lower than conventional methods), blocking prevention can be achieved. The melting points of the base materials 2b, 3b may be higher than or equal to those of the sealants 2a, 3a, or they may be similar. The difference in melting points between the sealants 2a, 3a and the base materials 2b, 3b may be within the range of 0 to 100°C or within the range of 25 to 55°C.

The packaging films 2 and 3 may have polyolefin resin layers in addition to the sealants 2a and 3a and the substrates 2b and 3b. For example, a polyolefin resin layer may be laminated on the outside of the substrates 2b and 3b. Alternatively, a polyolefin resin layer may be laminated between the sealants 2a and 3a and the substrates 2b and 3b. These polyolefin resin layers may be formed from stretched resin or from unstretched resin.

The proportion of sealants 2a and 3a relative to the thickness of packaging films 2 and 3 is preferably 50% or more, and may be around 60%, 70%, 80%, 90%, 95%, or an intermediate value. The proportion of the total thickness of the polyolefin resin layers (sealants 2a, 3a, base materials 2b, 3b, etc.) relative to the thickness of packaging films 2 and 3 is preferably 50% or more, and may be around 60%, 70%, 80%, 90%, 95%, 99%, or an intermediate value.

The sealants 2a and 3a and the substrates 2b and 3b may be laminated with an adhesive layer (not shown) in between. The adhesive layer may be formed from an adhesive or from an anchor coating agent. The material forming the adhesive layer is not particularly limited, but examples include urethane compounds, epoxy compounds, isocyanate compounds, polyethyleneimine, and organotitanium compounds such as titanium alkoxide. The thickness of the adhesive layer can be, for example, about 0.1 to 10 μm, about 1 to 6 μm, or about 3 to 4 μm. The adhesive layer may contain resin or it may be a resin-free adhesive layer.

The sealants 2a and 3a and the substrates 2b and 3b may be laminated with an extruded resin layer (not shown) in between. The material of the extruded resin is not particularly limited, but examples include adhesive resins, polyethylene resins, polypropylene resins, and polyolefin resins. The thickness of the extruded resin layer is not particularly limited, but examples include approximately 3 to 30 μm, 5 to 25 μm, and 7 to 20 μm.

A printed layer (not shown) may be present at one or more locations on the outer surfaces of the sealants 2a and 3a, the inner surfaces of the substrates 2b and 3b, or the outer surfaces of the substrates 2b and 3b. The printed layer can be formed by printing ink in a solid or patterned manner using printing methods such as gravure printing, letterpress printing, offset printing, screen printing, or inkjet printing. The thickness of the printed layer is not particularly limited, but is typically around 0.5 to 10 μm. The printed layer may be formed over the entire surface of the packaging films 2 and 3, or on a portion of the surface of the packaging films 2 and 3. Two or more printed layers may be superimposed.

The ink used to form the printed layer may contain colorants such as pigments and dyes, and a binder. The binder is not particularly limited, but examples include polyamide, polyurethane, polyester, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, acrylic polymer, polybutadiene, and cyclocompound rubber. The ink may also contain solvents such as water, organic solvents, and vegetable oils. After printing, the ink can be dried by solvent evaporation or ink curing. Heating or ultraviolet irradiation may be used to accelerate ink drying. The printed layer may contain resin, or it may be a resin-free printed layer.

The packaging films 2 and 3 may have layers of dissimilar materials (not shown) other than the resin layer, such as adhesive layers, vapor-deposited layers, printed layers, and coated layers. Examples of dissimilar materials include metals such as aluminum, and inorganic compounds such as silica and alumina. The printed layer, coated layer, and adhesive layer may contain resins other than polyolefin resins as materials for inks, paints, adhesives, etc. The method for forming the packaging films 2 and 3 is not particularly limited, but examples include dry lamination, extrusion lamination, heat lamination, co-extrusion, and coating. Different methods may be used to laminate each layer.

For monomaterial container packaging using specific resins, it is preferable that the total weight of the specific resins is 80% or more by weight of the total weight of the packaging films 2 and 3, and the total weight of materials other than the specific resins is 20% or less by weight. More preferably, the total weight of the specific resins is 90% or more by weight, and the total weight of materials other than the specific resins is 10% or less by weight. Examples of specific resins include polyolefin resins, polyethylene resins, or polypropylene resins. The packaging films 2 and 3 may use two or more resins that fall under the category of specific resins.

It is preferable that the sealants 2a, 3a and base materials 2b, 3b of the packaging films 2, 3 are made of the same type of resin. This same type of resin may be a combination of resins where the most abundant monomer (e.g., ethylene for PE, propylene for PP) is common, or a combination of resins where two monomers with high proportions (e.g., ethylene for EVA and vinyl acetate) are common. It is preferable to use a resin belonging to one of the following categories (PE, EVA, or PP) for both the sealants 2a, 3a and base materials 2b, 3b. For example, a combination of resins belonging to the same resin species (e.g., PE) but with different densities, etc., is also acceptable, such as HDPE for base materials 2b, 3b and LDPE, LLDPE for sealants 2a, 3a.

The use of packaging bag 4 is not particularly limited, including disposable, refill, storage, and storage of goods, but it is especially suitable for refilling the main container with contents once or multiple times. In this case, the main container can be made durable for long-term use, and the packaging of the refill container can be simplified. Furthermore, recycling becomes easier when disposing of the refill container after the contents have been used up.

It is preferable that the opening or tearing portion of the packaging bag 4 is formed in the packaging film 2 and 3. The opening or tearing portion may have a structure processed in the thickness direction of the packaging film 2 and 3, such as a perforation, notch, or half-cut groove; it may have a shape on the surface of the packaging film 2 and 3 that suggests opening or tearing, such as a thinly protruding spout; or it may be indicated by arrows, lines, dots, etc., printed on it. Cutting the packaging bag 4 is not limited to cutting at the opening point; it may be done at any desired location. For example, it is possible to cut between or around the packaging bags 4 in areas formed by connecting multiple packaging bags 4, or in areas formed by attaching tags or display parts around the packaging bag 4.

The dimensions of the packaging bag 4 are not particularly limited, but for example, when used as a refillable container, the height in the vertical direction is approximately 100 to 500 mm, the width in the horizontal direction is approximately 70 to 300 mm, and the filling volume is approximately 100 ^cm³ to 5000 ^cm³ . The contents may be in the form of fluids such as liquids, powders, or granules, or solids such as articles. The types of contents are not particularly limited, but may include detergents, chemicals, cosmetics, pharmaceuticals, beverages, seasonings, inks, paints, fuels, etc.

Although the present invention has been described above based on preferred embodiments, the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention. Modifications include the addition, substitution, omission, and other changes to the constituent elements.

Although not specifically shown in the illustrations, the folded portion 3 may be positioned on the side or top of the packaging bag 4. For example, when manufacturing a horizontal gusset bag using a manufacturing apparatus 10 equipped with a blocking prevention member 21, the folded portions 3 are inserted on both sides of the width direction 6 of the main surface 2 of the body, and the longitudinal direction 5 is set in the vertical direction of the packaging bag 4. A blocking prevention member 21 is positioned at each of the folded portions 3.

For example, as shown in Figure 8 of Japanese Patent Publication No. 4381724, folded portions 3, 3 may be sandwiched on both the left and right sides of a pair of main surfaces 2, 2. Alternatively, as shown in Figure 9 of the same publication, the pair of main surfaces 2, 2 and the folded portions 3, 3 on both sides may be formed from a single tube, and the folded portions 3, 3 may be folded and overlapped with the main surfaces 2, 2.

1... Raw film roll, 2... Main surface of the body, 2a... Sealant for the main surface, 2b... Base material for the main surface, 3... Folded portion, 3a... Sealant for the folded portion, 3b... Base material for the folded portion, 3c... Fold line, 3d... Tape-shaped film, 4... Packaging bag, 4a... Bottom of the packaging bag, 4b... Side of the packaging bag, 5... Longitudinal direction, 6... Width direction, 10... Packaging bag manufacturing apparatus, 11... Buffer means, 12... Bi-folding means, 12a... Joining roll, 13... First conveying means, 13a... Roll member, 14... Insertion means, 14a... Perforation means, 15... Joining means, 15a... Heater for the joining means, 15b... Cooling part for the joining means, 16... Sealing means, 16a... Heater for the sealing means, 16b... Cooling part for the sealing means, 17... Cutting means, 18... Second conveying means, 20... Blocking prevention means, 21... Blocking prevention member, 22... Support member.

Claims (10)

A packaging bag manufacturing apparatus having a folded portion, which is folded along a fold line, between the main surfaces of the body,
A conveying means for conveying the packaging film forming the body in the longitudinal direction,
A joining means for joining the main surface of the body and the folded portion by heat welding,
The packaging film comprises, in the longitudinal direction, at least in the section including the joining means, a blocking prevention member inserted inside the folded portion,
A packaging bag manufacturing apparatus characterized in that, while the packaging film is conveyed in the longitudinal direction, the blocking prevention member is stopped relative to the longitudinal direction, and the blocking prevention member is a molded resin body, a resin film, a resin sheet, or a resin board with a thickness of 10 μm to 1 mm . The body portion is formed by sandwiching a folded film, which is folded in half along a fold line, between the body films that form the main surface of the body portion.
The manufacturing apparatus for packaging bags according to claim 1, characterized in that it comprises an insertion means for inserting the folded film between the body films. The packaging bag manufacturing apparatus according to claim 1 or 2 , characterized in that the blocking prevention member is a film or sheet made of a resin selected from polyester resin, polyamide resin, and fluororesin. A packaging bag manufacturing apparatus according to any one of claims 1 to 3 , wherein a sealing means for sealing the periphery of the packaging bag is provided downstream of the joining means, and the blocking prevention member is arranged upstream of the sealing means. A method for manufacturing a packaging bag having a folded portion, which is folded along a fold line, between the main surfaces of the body,
A conveying step for conveying the packaging film forming the body in the longitudinal direction,
The process includes a joining step of joining the main surface of the body and the folded portion by heat welding,
In the longitudinal direction of the packaging film, in a section including at least the location where the joining process is performed, a blocking prevention member is inserted inside the folded portion.
A method for manufacturing a packaging bag, characterized in that the blocking prevention member is stopped relative to the longitudinal direction while the packaging film is conveyed in the longitudinal direction, and the blocking prevention member is a molded resin body, a resin film, a resin sheet, or a resin board with a thickness of 10 μm to 1 mm . The body portion is formed by sandwiching a folded film, which is folded in half along a fold line, between the body films that form the main surface of the body portion.
The method for manufacturing a packaging bag according to claim 5 , characterized in that, prior to the joining step, it includes an insertion step of inserting the folded film between the body films. The method for manufacturing a packaging bag according to claim 5 or 6 , characterized in that the packaging film is a laminated film having a sealant and a substrate, and the difference in melting points between the sealant and the substrate of the packaging film is 0 to 100°C. A method for manufacturing a packaging bag according to any one of claims 5 to 7 , characterized in that the folded portion has a polyethylene resin on its outer surface. The method for manufacturing a packaging bag according to any one of claims 5 to 8 , characterized in that the packaging film is a laminated film having a sealant and a base material made of polyethylene resin. A method for manufacturing a packaging bag according to any one of claims 5 to 9, characterized in that the packaging film is a laminated film having a sealant and a substrate, and the sealant and the substrate of the packaging film are the same type of resin belonging to one selected from polyethylene ( PE ), ethylene-vinyl acetate copolymer (EVA), and polypropylene (PP).