Bag-making method, bag-making device

Abstract

To provide a bag-making method capable of suppressing sticking of a content.SOLUTION: The bag-making method comprises a coating step, a drying step, and a heat-sealing step. In the coating step, a film rewound from a raw fabric roll is coated with a dispersion liquid, and the dispersion liquid includes a dispersion medium, and repellent particles dispersed in the dispersion medium. In the drying step, the dispersion medium is evaporated to dry the film. In the heat-sealing step, the film is heat-sealed to be formed into a bag shape after the drying step.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a bag-making method and a bag-making apparatus.

Background Art

[0002] Patent Document 1 discloses a bag-making method including a step of forming a film into a bag shape by heat-sealing the film unwound from a raw material roll.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the bag produced by the method of Patent Document 1, the contents are likely to adhere to the inner surface of the bag. For this reason, a bag-making method capable of suppressing the adhesion of the contents is desired.

[0005] The present invention has been made in view of such circumstances, and provides a bag-making method capable of suppressing the adhesion of the contents.

Means for Solving the Problems

[0006] According to the present invention, there is provided a bag-making method including a coating step, a drying step, and a heat-sealing step. In the coating step, a dispersion liquid is applied to the film unwound from the raw material roll. The dispersion liquid includes a dispersion medium and water-repellent particles dispersed in the dispersion medium. In the drying step, the dispersion medium is evaporated to dry the film. In the heat-sealing step, after the drying step, the film is heat-sealed to form the film into a bag shape.

[0007] In the present invention, a dispersion containing water-repellent particles is applied to a film, and after the film is dried, heat sealing is performed to form a bag. Since the water-repellent particles adhere to the inner surface of the bag manufactured in such a manner, the adhesion of the contents is suppressed.

[0008] Hereinafter, various embodiments of the present invention will be exemplified. The embodiments shown below can be combined with each other. Preferably, it is the bag-making method described above, and in the coating step, the dispersion is applied to the film with tension applied thereto. Preferably, it is the bag-making method described above, and in the heat-sealing step, the heat sealing is performed intermittently, and in the coating step, tension is constantly applied to the film by tension rollers and feed rollers provided before and after the position where the dispersion is applied. Preferably, it is the bag-making method described above, and the coating is performed by spraying. Preferably, it is the bag-making method described above, and the heat sealing includes a horizontal seal in a direction perpendicular to the longitudinal direction of the film, and in the coating step, the dispersion is not applied to the film in the region where the horizontal seal is performed. Preferably, it is the bag-making method described above, and the heat sealing includes a longitudinal seal in a direction along the longitudinal direction of the film, and in the coating step, the dispersion is not applied to the film in the region where the longitudinal seal is performed. Preferably, it is the bag-making method described above, and in the coating step, the dispersion is applied to one surface of the film, and in the drying step, the film is guided via a guide roller, and the guide roller is arranged so as not to contact the one surface. Preferably, it is the bag-making method described above, and the coating is performed by passing the film through an immersion tank containing the dispersion. Preferably, it is the bag-making method described above, and the drying step is performed while pulling up the film from the immersion tank. Preferably, the bag-making method described above, wherein the dispersion contains resin beads dispersed in the dispersion medium, is a bag-making method. Preferably, the bag-making method described above, wherein the coating step includes first and second coating steps. In the first coating step, a first dispersion is applied to the film, and in the second coating step, a second dispersion is applied to the film. The first dispersion contains a first dispersion medium and the resin beads dispersed in the first dispersion medium, and the second dispersion contains a second dispersion medium and the water-repellent particles dispersed in the second dispersion medium. The first and second coating steps are separate steps, and this is a bag-making method. Preferably, the bag-making method described above, wherein the second coating step is performed after the first coating step, is a bag-making method. Preferably, the bag-making method described above, wherein the drying step is performed in the same drying section after each of the first coating step and the second coating step, is a bag-making method. Preferably, the bag-making method described above, wherein the film has an uneven shape before the coating step, is a bag-making method. Preferably, a bag-making apparatus includes a coating section, a drying section, and a heat-sealing section. In the coating section, a dispersion is applied to a film unwound from a raw material roll. The dispersion contains a dispersion medium and water-repellent particles dispersed in the dispersion medium. In the drying section, the dispersion medium is evaporated to dry the film. In the heat-sealing section, after the drying step, the film is heat-sealed to form the film into a bag shape, and this is a bag-making apparatus.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described. Various characteristic matters shown in the following embodiments can be combined with each other. Also, an invention can be established independently for each characteristic.

[0011] 1. First Embodiment The bag-making apparatus 1 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 2. The bag-making apparatus 1 includes a raw film roll 12, guide rollers 3a to 3k, a tension roller 4, feed rollers 5a to 5c, a dancer roller 6, a spray mechanism (an example of a “coating section”) 7, a drying chamber (an example of a “drying section”) 8, a cooling chamber 9, a film processing mechanism 10, and a heat seal section 11. By the bag-making apparatus 1, a bag-making method according to an embodiment of the present invention can be implemented.

[0012] <Raw film roll 12> The raw film roll 12 is a roll around which the film 2 is wound. The film 2 is unwound from the raw film roll 12 by the force with which the feed roller 5a feeds out the film 2. The shaft 12a on which the raw film roll 12 is mounted may be rotationally driven to feed out the film 2.

[0013] <Film 2> The film 2 only needs to have a heat-sealing layer and be capable of heat-sealing between films. Examples of the film 2 include a single-layer film made of a thermoplastic resin having heat-sealing properties, sheets, and multilayer films in which a thermoplastic resin having heat-sealing properties is laminated with other thermoplastic resins or the like. Further, examples of materials having good heat-sealing properties include known olefin resins such as low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, polypropylene, propylene-ethylene copolymer, ethylene-vinyl acetate copolymer, and olefin resins graft-modified with an ethylenic unsaturated carboxylic acid or its anhydride; polyamide or copolyamide resins having a relatively low melting point or low softening point; polyester or copolyester resins; polycarbonate resins; and the like. In addition, various barrier films can be used as other plastic materials to be laminated. When using a laminated film, it is preferable to thermally weld the heat-sealing thermoplastic resin layers having good heat-sealing properties, such as resins with a low melting point, with each other on the inner surface side.

[0014] <Guide rollers 3a to 3c, tension roller 4> Between the raw material roll 12 and the feed roller 5a, guide rollers 3a, tension roller 4, guide rollers 3b, and 3c are arranged in this order. The guide rollers are provided to suppress the meandering, wrinkles, slack, etc. of the film 2, and the number and installation location are set as appropriate.

[0015] The tension roller 4 is configured to apply tension to the film 2. Specifically, the tension roller 4 is constantly biased toward the film 2 by a biasing means such as its own weight or a spring.

[0016] <Spray mechanism 7> The spray mechanism 7 is disposed between the tension roller 4 and the feed roller 5a. Since the tension rollers 4 and the feed roller 5a provided before and after the spray mechanism 7 constantly apply tension to the film 2, in the spray mechanism 7, the dispersion liquid 13 (details will be described later) is sprayed (an example of "coating") onto the film 2 in a state where tension is applied to the film 2 (coating step). If the dispersion liquid 13 is applied in a state where the film 2 is slack, the dispersion liquid 13 may be unevenly applied. However, in the present embodiment, since the dispersion liquid 13 is applied to the film 2 in a state where tension is applied to the film 2, the dispersion liquid 13 can be uniformly applied.

[0017] The region where the spray mechanism 7 applies the dispersion liquid 13 is not particularly limited, and it may be applied to the entire surface of the film 2 or to a partial region. If the dispersion liquid 13 is applied to the region where the longitudinal seal or the transverse seal is performed, the seal strength may decrease. Therefore, it is preferable not to apply the dispersion liquid 13 to the region where the longitudinal seal is performed and the region where the transverse seal is performed. The longitudinal seal is a heat seal in the direction along the longitudinal direction of the film, and the transverse seal is a heat seal in the direction perpendicular to the longitudinal direction of the film.

[0018] In the present embodiment, as shown in FIG. 2B, by covering the regions near both ends of the film 2 with the cover 14, the dispersion liquid 13 is not applied to the region where the longitudinal seal is performed. Further, by moving the film 2 in the longitudinal direction with the spraying of the dispersion liquid stopped, the dispersion liquid 13 is not applied to the region where the transverse seal is performed.

[0019] For this reason, on one surface of the film 2 after passing through the spray mechanism 7, a coated region 2a where the dispersion liquid 13 is applied, a non-coated region 2b including the region where the longitudinal seal is performed, and a non-coated region 2c including the region where the transverse seal is performed are formed. The dispersion liquid 13 is not applied to the other surface of the film 2, and the entire surface is a non-coated region.

[0020] <Dispersion liquid 13> Dispersion liquid 13 contains a dispersion medium, resin beads, and water-repellent particles. After applying such a dispersion liquid 13 and evaporating the dispersion medium in the drying process, an uneven shape is formed on the surface of film 2 by the resin beads, and a structure in which the water-repellent particles adhere to the uneven surface is obtained. When such a structure is formed on the inner surface of the bag to be manufactured, the physical action due to the uneven shape and the chemical action due to the water-repellent particles make it difficult for the contents to adhere.

[0021] Dispersion liquid 13 contains a dispersion medium, resin beads, and water-repellent particles. The dispersion medium may be any liquid capable of dispersing the resin beads and the water-repellent particles, and examples include water and alcohol (e.g., ethanol).

[0022] · Resin beads By attaching the resin beads to film 2, better abrasion resistance and the like can be imparted to the packaging material.

[0023] As the resin beads, for example, beads of resin components (or organic polymer components) such as acrylic resins, urethane resins, melamine resins, amino resins, epoxy resins, polyethylene resins, polystyrene resins, polypropylene resins, polyester resins, cellulose resins, vinyl chloride resins, polyvinyl alcohol, ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, ethylene-ethyl acrylate copolymers, polyacrylonitrile, polybutyl methacrylate, polyacrylate esters, polymethyl methacrylate, polyamides, etc. can be preferably used.

[0024] The shape of the resin beads is not limited, and it may be, for example, spherical, ellipsoidal of revolution, irregular, teardrop-shaped, flat, hollow, porous, etc.

[0025] The average particle size of the resin beads is not particularly limited, and can be appropriately set, for example, in the range of 1 to 50 μm, preferably 1 to 30 μm. However, in relation to actively utilizing the gaps between the resin beads, it is preferable that the average particle size of the resin beads is larger than the average primary particle diameter of the water-repellent particles.

[0026] It is desirable that the melting point of the resin beads is lower than that of the heat-sealing layer, and more preferably 160°C or lower. By adopting resin beads with such a melting point, the adhesion of the resin beads to the heat-sealing layer is improved, and the abrasion resistance and non-adhesiveness can be more effectively maintained. From this perspective, the material of the resin beads is preferably a polyolefin-based resin, and for example, at least one of a polyethylene-based resin, a polypropylene resin, a polybutene resin, etc. can be suitably used.

[0027] Even when the melting point of the resin beads is higher than that of the heat-sealing layer, if a heat-sealing layer with a low melting point is adopted, the adhesion between the resin beads and the heat-sealing layer will be improved, and the abrasion resistance and non-adhesiveness can be effectively maintained in the same way as above. That is, by welding a part of the resin beads and a part of the surface of the heat-sealing layer, the resin beads are firmly fixed on the heat-seal, and the abrasion resistance and non-adhesiveness can be more effectively maintained by the synergistic effect with the water-repellent particles adhering to the gap and the surface.

[0028] The average particle diameter of the resin beads can be measured by a laser diffraction particle size distribution analyzer. However, when it is difficult to measure by a laser diffraction particle size distribution analyzer, observe with a microscope, for example, observe (or take a photo) with a scanning electron microscope, etc. When the particle shape is spherical, take its diameter, and when it is non-spherical, take the average value of the longest diameter and the shortest diameter as the diameter, and take the average of the diameters of 20 arbitrarily selected particles observed by a scanning electron microscope, etc. as the average particle diameter.

[0029] The adhesion amount of the resin beads in the packaging material of the present invention can be appropriately changed according to the type, average particle diameter, etc. of the resin beads, but it is usually preferably about 1.0 to 10.0 g / m 2 and more preferably about 2.0 to 4.0 g / m 2 is even more preferable.

[0030] · Water-repellent particles As the water-repellent particles, those having hydrophobicity are not particularly limited, and specifically, oxide fine particles having hydrophobicity or the like can be used. Further, those hydrophobized by surface treatment may also be used. For example, hydrophilic oxide fine particles can be surface-treated with a silane coupling agent or the like to use fine particles having a hydrophobic surface state.

[0031] More specifically, as the oxide fine particles, at least one of silica (silicon dioxide), alumina, titania, etc. can be preferably used. Among these, hydrophobic silica fine particles can be preferably used. In particular, hydrophobic silica fine particles having a trimethylsilyl group on the surface are preferable in terms of obtaining more excellent non-adhesiveness. Examples of commercially available products corresponding to this include the above-mentioned "AEROSIL R812", "AEROSIL R812S" (both manufactured by Evonik Degussa Co., Ltd.), etc.

[0032] The adhesion amount (weight after drying) of the water-repellent particles adhered to the surface of the packaging material is not limited, but is usually preferably 0.01 to 10 g / m 2 and more preferably 0.2 to 1.5 g / m 2 and most preferably 0.2 to 1 g / m 2 By setting within the above range, more excellent non-adhesiveness can be obtained over a long period of time, and it is more advantageous also in terms of suppressing the dropout of the water-repellent particles and cost. The water-repellent particles adhered to the surface of the packaging material preferably form a porous layer having a three-dimensional network structure, and its thickness is preferably about 0.1 to 5 μm, and more preferably about 0.2 to 2.5 μm. By adhering in such a porous layer state, the layer can contain a large amount of air and can exhibit more excellent non-adhesiveness.

[0033] The average primary particle diameter of the water-repellent particles is preferably about 3 nm to 20 μm, more preferably 3 to 100 nm, and most preferably 5 to 50 nm. In the present invention, the measurement of the average primary particle diameter can be carried out with a scanning electron microscope (SEM, FE-SEM). When the resolution of the scanning electron microscope is low, other electron microscopes such as a transmission electron microscope may be used in combination. Specifically, when the particle shape is spherical, its diameter is used, and when it is non-spherical, the average value of the longest diameter and the shortest diameter is regarded as the diameter, and the average of the diameters of 20 arbitrarily selected particles observed with a scanning electron microscope or the like is taken as the average primary particle diameter.

[0034] <Feed roller 5a> The feed roller 5a has a function of moving the film 2 along the longitudinal direction by being rotationally driven while gripping the film 2 with a pair of rollers. The feed roller 5a adjusts the feed speed so that the passing speed of the film 2 in the coating process becomes constant. This enables uniform coating of the dispersion liquid 13.

[0035] In the present embodiment, as shown in FIG. 2C, the feed roller 5a includes a left feed roller 5a1 and a right feed roller 5a2. The left feed roller 5a1 is composed of a pair of rollers 5a1u and 5a1b. The right feed roller 5a2 is composed of a pair of rollers 5a2u and 5a2b. The left feed roller 5a1 and the right feed roller 5a2 are each configured to grip the non-coated region 2b. According to such a configuration, since the feed roller 5a does not contact the coated region 2a, adhesion of the dispersion liquid 13 to the feed roller 5a is suppressed. Note that the roller 5a1b and the roller 5a2b may be connected to form one roller. Since the entire lower surface of the film 2 is a non-coated region, even if configured in such a manner, the dispersion liquid 13 does not adhere to the roller.

[0036] <Drying chamber 8> The inside of the drying chamber 8 is at a high temperature. By passing the film 2 through the inside of the drying chamber 8, the dispersion medium is evaporated to dry the film (drying process). As a result, the resin beads and the water-repellent particles can be attached to the film 2. The drying process may be performed, for example, by irradiating the film 2 with heat rays using a heater to heat the film 2 without using the drying chamber 8.

[0037] The drying temperature may be any temperature at which the dispersion medium can be evaporated, but is preferably a temperature equal to or higher than the melting point of the resin beads. In this case, the resin beads are firmly fused to the film 2. Further, the drying temperature is preferably set to a temperature at which the heat-sealing layer substantially maintains its original shape and the resin beads are welded to the surface of the heat-sealing layer. More specifically, it is preferable to heat to a temperature lower than the melting point of the heat-sealing layer and equal to or higher than the melting point of the resin beads. In particular, it is preferably 130 to 200 °C. The drying temperature is preferably, for example, 130 to 200 °C.

[0038] In the drying chamber 8, the film 2 is guided along the wall surface of the drying chamber 8 via the guide rollers 3d to 3f. By guiding the film 2 along the wall surface, the time for which the film 2 stays in the drying chamber 8 is prolonged, and drying can proceed more sufficiently. The guide rollers 3d to 3f are arranged so as not to contact the surface of the film 2 on which the dispersion liquid 13 is applied (that is, they are arranged to contact the surface opposite to the surface having the coating region 2a). For this reason, adhesion of the dispersion liquid 13 to the guide rollers 3d to 3f is suppressed.

[0039] <Cooling chamber 9> The film 2 from the drying chamber 8 is guided to the cooling chamber 9 by the guide rollers 3g, 3h. In the cooling chamber 9, the film 2 that has become hot in the drying chamber 8 is cooled. In the cooling chamber 9, the film 2 may be cooled to such an extent that there is no inconvenience in subsequent processes. The cooling chamber 9 can be omitted if not required.

[0040] <Feed roller 5b> The film 2 from the cooling chamber 9 is guided to the feed roller 5b by the guide roller 3i. The feed roller 5b has a function of moving the film 2 along the longitudinal direction by being rotationally driven while gripping the film 2 with a pair of rollers. By providing the feed roller 5b on the downstream side of the drying chamber 8, it becomes easier to adjust the drying conditions. The feed roller 5b continuously feeds the film 2 at a constant speed.

[0041] One of the feed rollers 5a and 5b can be omitted. When omitting one, it is preferable to omit the feed roller 5a.

[0042] When the film 2 comes into contact with the feed roller 5b, since the film 2 is already dry at this time, the feed roller 5b may have a structure that contacts the coating area 2a. In this case, since the feed roller 5b can contact the entire width direction of the film 2 to feed the film 2, the feeding of the film 2 can be stably performed.

[0043] <Dancer roller 6, film processing mechanism 10, heat seal part 11, feed roller 5c> Between the feed roller 5b and the feed roller 5c, a dancer roller 6, guide rollers 3j and 3k are provided. Between the guide rollers 3j and 3k, a film processing mechanism 10 and a heat seal part 11 are provided.

[0044] The film processing mechanism 10 processes the film 2 so that a desired bag can be obtained by heat sealing. The processing here means folding, cutting, etc. of the film. Also, in the film processing mechanism 10, the film 2 is stacked to form a laminated film 2d so that the parts where heat sealing is performed become multiple layers. The types of bags are not limited and can be any of two-sided bags, three-sided bags, three-sided bags with a chuck, clasp bags, gusset bags, bottom gusset bags, stand bags, stand chuck bags, four-sided column flat bottom gusset bags, side seal bags, bottom seal bags, etc.

[0045] In the heat seal part 11, heat sealing is performed on the laminated film 2d to form a bag-shaped, heat-sealed film 2e (heat sealing process). Heat sealing can be performed by pressing a seal bar heated to a temperature at which the heat seal layer can be melted against the film 2 stacked in multiple layers. The heat sealing can include a horizontal seal in a direction perpendicular to the longitudinal direction of the film 2 and a vertical seal in a direction along the longitudinal direction of the film 2. The horizontal seal and the vertical seal can be performed in either order.

[0046] The heat seal part 11 may include a filling part for filling the contents. In this case, for example, a vertical bag-making and filling machine is preferable. After heat sealing is performed so that a bag that is open only at the top is formed, the contents are filled, and then the top of the contents is heat-sealed to seal the contents.

[0047] In the present embodiment, it is assumed that bag-making is for refill pouches or industrial pouches, rather than small bags (less than 100 mL). The content volume is, for example, 250 ml, 300 ml, 500 ml, 1 L, 2 L, 5 L, 10 L, 15 L, 20 L, etc. Therefore, in order to increase the seal strength, intermittent drive sealing is performed instead of continuous sealing.

[0048] In intermittent drive heat sealing, the seal bar is pressed against the laminated film 2d with the laminated film 2d stopped. Therefore, since the seal bar can be pressed for a time sufficient to obtain the required strength, the seal strength can be increased.

[0049] In intermittent drive heat sealing, the heat-sealed film 2e can be manufactured by repeating the process of feeding the laminated film 2d by a predetermined length and the heat sealing process.

[0050] When filling the contents, the steps of feeding the laminated film 2d by a predetermined length, the first heat-sealing step, the contents filling step, and the second heat-sealing step are repeated. In the first heat-sealing step, heat-sealing is performed so as to form a bag that is open only at the top. In the second heat-sealing step, the top of the contents is heat-sealed to seal the contents.

[0051] Incidentally, the feed roller 5c has a function of moving the formed bag film 2e, the laminated film 2d connected thereto, and the film 2 along the longitudinal direction by being rotationally driven while gripping the formed bag film 2e with a pair of rollers. The feed roller 5b feeds the film 2 at a constant speed, and the feed roller 5c intermittently operates to feed the formed bag film 2e in accordance with the seal time and the filling time.

[0052] The feed roller 5b continues to operate even while the feed roller 5c is stopped. At this time, the dancer roller 6 is driven to move between the positions 6a and 6b in order to prevent the film 2 from sagging. Specifically, immediately after the feed roller 5c stops, the dancer roller 6 is disposed at the position 6b, and thereafter, the dancer roller 6 gradually moves toward the position 6a in synchronization with the feeding of the film 2 by the feed roller 5b. By moving the dancer roller 6 in this way, the occurrence of slack in the film 2 is suppressed.

[0053] Also, when the feed roller 5c is rotationally driven, the dancer roller 6 moves to the position 6b. As a result, the feeding of the film 2 by the feed roller 5c becomes smooth. Although it is also possible to use a tension roller instead of the dancer roller 6, the dancer roller 6 has an advantage that it can move actively from the position 6a to the position 6b, so that the feeding of the film can be made smoother than that of the tension roller.

[0054] The formed bag film 2e is cut as needed on the downstream side of the feed roller 5c so that individual bags are formed.

[0055] 2. Second Embodiment Referring to FIG. 3, a second embodiment of the present invention will be described. This embodiment is similar to the first embodiment, and the main difference lies in the configuration of the drying chamber 8. Hereinafter, the description will focus on the differences.

[0056] In this embodiment, guide rollers 3u and 3v are arranged non-parallelly in the drying chamber 8. The film 2 is guided so as to be spirally wound around the guide rollers 3u and 3v. According to such a configuration, the time for which the film 2 stays in the drying chamber 8 can be lengthened, and the film 2 can be effectively dried.

[0057] 3. Third Embodiment Referring to FIG. 4, a third embodiment of the present invention will be described. This embodiment is similar to the first embodiment, and the main differences lie in the configurations of the spray mechanism and the drying chamber. Hereinafter, the description will focus on the differences.

[0058] In this embodiment, first and second spray mechanisms (an example of the "coating section") 7a and 7b are provided. The first spray mechanism 7a applies the first dispersion liquid 13a (first coating step). The second spray mechanism 7b applies the second dispersion liquid 13b (second coating step). The first and second coating steps are separate steps, and the second coating step is performed after the first coating step. The first dispersion liquid 13a contains a first dispersion medium and resin beads dispersed in the first dispersion medium. The second dispersion liquid 13b contains a second dispersion medium and water-repellent particles dispersed in the second dispersion medium. The first and second dispersion media may be the same or different. The dispersion medium, resin beads, and water-repellent particles are as described in the first embodiment.

[0059] In the first coating step, the film 2 coated with the first dispersion liquid 13a is introduced into the drying chamber 8 and dried. The second dispersion liquid 13b is applied to the film 2 led out from the drying chamber 8 in the second coating step, and this film 2 is introduced into the drying chamber 8 again and dried. Thus, in the present embodiment, the drying after the first coating step and the drying after the second coating step are performed in the same drying chamber 8. Therefore, the equipment cost can be reduced.

[0060] In addition, since the resin beads contained in the first dispersion liquid 13a are subjected to two drying steps, the resin beads are likely to be welded to the film 2.

[0061] The film 2 is guided by the guide rollers 3b to 3f and 3l to 3p. The arrangement and number of the guide rollers can be changed as appropriate.

[0062] 4. Fourth Embodiment The fourth embodiment of the present invention will be described with reference to FIG. 5. This embodiment is similar to the first embodiment, and the main difference is the configuration of the coating portion. Hereinafter, the description will focus on the differences.

[0063] The bag-making apparatus 1 of this embodiment includes an immersion tank (an example of the "coating portion") 17. The same dispersion liquid 13 as in the first embodiment is contained in the immersion tank 17, and the dispersion liquid 13 can be applied to the film 2 by passing the film 2 through the immersion tank 17.

[0064] In the method of this embodiment, since the dispersion liquid 13 is applied to the entire surfaces of both sides of the film 2, the rollers cannot be arranged so that the rollers do not contact the coated surfaces.

[0065] Therefore, in the present embodiment, a feed roller 5f is arranged on the downstream side of the drying chamber 8, and the film 2 is configured to be pulled up from the immersion tank 17 by the feed roller 5f. Since the feed roller 5f contacts the film 2 after the film 2 is dried, the dispersion liquid 13 does not adhere to the feed roller 5f. By pulling up the film 2 at a constant speed by the feed roller 5f, the dispersion liquid 13 is uniformly applied to the film 2.

[0066] On the upstream side of the immersion tank 17, feed rollers 5d and 5e are provided, and a guide roller 3s is provided between the feed rollers 5d and 5e. The functions of the feed rollers 5d to 5f are the same as those of the feed roller 5a.

[0067] The feed roller 5d pulls out the film 2 from the raw film roll 12 and sags the film 2 between the feed roller 5d and the guide roller 3s. This facilitates the adjustment of the feeding speed of the film 2 by the feed roller 5e.

[0068] The feed roller 5e is preferably arranged such that the film feeding side of the film 2 is located above the immersion tank 17. In this case, the film 2 fed out from the feed roller 5e smoothly enters the immersion tank 17.

[0069] The feeding speed of the film 2 by the feed roller 5e is preferably equal to or higher than the feeding speed of the film 2 by the feed roller 5f, and more preferably, the feeding speeds of the film 2 by the feed rollers 5e and 5f are equal.

[0070] The present embodiment can also be implemented with the following modification examples.

[0071] · Modification Example 1 In Modification Example 1, the feed roller 5d is not provided, and the film 2 is unwound from the raw film roll 12 by rotationally driving the shaft 12a. The film 2 is sagged between the raw film roll 12 and the guide roller 3s.

[0072] · Modification Example 2 In Modification 2, the feed roller 5d and the guide roller 3s are not provided, and the film 2 is unwound from the raw film roll 12 only by the feeding force of the feed roller 5e.

[0073] ·Modification 3 In Modification 3, instead of the immersion tank 17, a mist chamber filled with mist is prepared by atomizing the dispersion liquid 13, and the film 2 is passed through the mist chamber to attach the mist of the dispersion liquid 13 to the film 2, thereby applying the dispersion liquid 13 to the film 2. The mist chamber is preferably under positive pressure.

[0074] 5. Fifth Embodiment The fifth embodiment of the present invention will be described. This embodiment is similar to the first embodiment, and the main differences are the differences in the dispersion liquid 13 and the film 2. Hereinafter, the description will focus on the differences.

[0075] In this embodiment, the film 2 has an uneven shape at the time before the coating step. For example, the uneven shape can be formed on the film 2 by forming the film 2 using a raw material resin containing particles capable of forming the uneven shape. Such particles are preferably larger than the above-mentioned water-repellent particles and do not melt under the molding conditions when manufacturing the film 2, and examples thereof include inorganic particles such as silica.

[0076] When the film 2 has an uneven shape, as the dispersion liquid 13, one containing no resin beads and containing a dispersion medium and water-repellent particles can be used. This is because the uneven shape has already been formed on the film 2.

[0077] 6. Others The coating method when applying the dispersion liquid 13 is not limited to the above, and for example, any known methods such as roll coating, gravure coating, bar coating, doctor blade coating, comma coater, and brush coating can be adopted. When applying the water-repellent particles to the uneven surface, coating by spray or immersion tank is more preferable than roll coating. This is because it is easier to attach the water-repellent particles to the details of the concave portions.

[0078] Examples of the contents include foods, beverages, pharmaceuticals, cosmetics, chemicals, etc., such as jelly confectionery, pudding, yogurt, liquid detergent, toothpaste, curry roux, syrup, petrolatum, mayonnaise, ketchup, sauce, dressing, fats and oils, butter, margarine, flower paste, chocolate, jam, liquid eggs, cheese, facial cleansing cream, facial cleansing foam, etc. Further, the properties of the contents vary, including solids, semi-solids, liquids, viscous substances, gel-like substances, etc. Moreover, the contents may be any of oil-based, water-based, or amphoteric. When the contents are oil-based, it is preferable to use water-repellent particles that also have oil-repellent properties. The contents may contain solids.

[0079] The specifications of the bag-making device 1 can be set as appropriate, and the number and arrangement of various components constituting the bag-making device 1 can be set as appropriate.

[0080] In the bag-making device 1, the advantages of applying the dispersion liquid and drying the film are as follows. · Relatively inexpensive films can be used. · Limitations on film configuration (layer configuration, thickness, etc.) are eliminated. · With a single raw film roll, it becomes possible to manufacture both products with the dispersion liquid applied and those without the application. For example, when filling the contents, as the contents change, it is possible to select whether to apply or not, so there is no need to replace the raw film roll.

Explanation of Reference Numerals

[0081] 1: Bag-making device 2: Film 2a: Coating area 2b: Non-coating area 2c: Non-coating area 2d: Laminated film 2e: Film 3a~3v: Guide roller 4: Tension roller 5a~5f: Feeding roller 6: Dancer roller 7: Spray mechanism 7a: First spray mechanism 7b: Second spray mechanism 8: Drying chamber 9: Cooling chamber 10: Film processing mechanism 11: Heat seal part 12: Base fabric roll 12a: Shaft 13: Dispersion liquid 13a: First dispersion liquid 13b: Second dispersion liquid 14: Cover 17: Immersion tank

Claims

1. A bag-making method comprising a coating step, a drying step, and a heat-sealing step, wherein: In the coating step, a dispersion is applied to the film unwound from the raw roll around which the film having a heat-sealing layer is wound; The dispersion contains a dispersion medium and water-repellent particles dispersed in the dispersion medium; In the drying step, the dispersion medium is evaporated to dry the film; In the heat-sealing step, after the drying step, the film is heat-sealed to form the film into a bag shape; Between after the drying step and before the heat-sealing step, the film is not wound up in a roll shape, and at the time of heat-sealing the film, the heat-sealing portion of the film is connected to the raw roll; The coating is performed by passing the film through an immersion tank containing the dispersion; The drying step is performed while pulling up the film from the immersion tank by a first feed roller; The first feed roller is configured to move the film along the longitudinal direction by being rotationally driven while gripping the film with a pair of rollers; The first feed roller is disposed vertically above the immersion tank; The drying step is performed in a drying chamber disposed between the first feed roller and the immersion tank; The film is in a slack state in the immersion tank; A bag-making method, wherein no roller contacting the film is provided between the immersion tank and the first feed roller.

2. The method according to Claim 1, wherein: Upstream of the immersion tank, a second feed roller, a guide roller, and a third feed roller are provided in this order from the immersion tank side; Each of the second and third feed rollers is configured to move the film along the longitudinal direction by being rotationally driven while gripping the film with a pair of rollers; The film is in a slack state between the guide roller and the third feed roller.

3. The method according to Claim 2, wherein: The third feed roller pulls out the film from the raw roll.

4. The method according to Claim 2 or Claim 3, wherein: The feeding speed of the film by the second feed roller is equal to or higher than the feeding speed of the film by the first feed roller.

5. The method according to Claim 4, wherein: A method in which the film feeding speed by the second feeding roller is equal to the film feeding speed by the first feeding roller.

6. The method according to any one of Claims 2 to 5, wherein the second feeding roller is arranged such that the film feeding side is located vertically above the dipping tank.

7. The method according to any one of Claims 1 to 6, wherein in the coating step, the dispersion liquid is applied to the entire surfaces of both sides of the film.

8. The method according to any one of Claims 1 to 7, wherein the first feeding roller contacts the film after the film is dried.

9. The method according to any one of Claims 1 to 8, wherein the first feeding roller pulls up the film at a constant speed.

10. A bag-making method according to any one of Claims 1 to 9, wherein the dispersion liquid contains resin beads dispersed in the dispersion medium.

11. A bag-making method according to any one of Claims 1 to 9, wherein the coating step includes a first and a second coating step, in the first coating step, a first dispersion liquid is applied to the film, in the second coating step, a second dispersion liquid is applied to the film, the first dispersion liquid contains a first dispersion medium and resin beads dispersed in the first dispersion medium, the second dispersion liquid contains a second dispersion medium and the water-repellent particles dispersed in the second dispersion medium, and the first and second coating steps are separate steps.

12. A bag-making method according to Claim 11, wherein the second coating step is performed after the first coating step.

13. A bag-making method according to Claim 11 or Claim 12, wherein the drying step is performed in the same drying section after each of the first coating step and the second coating step.

14. A bag-making method according to any one of Claims 1 to 11, wherein the film has an uneven shape at a point before the coating step.

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