JP7267827B2 - Packaging bag manufacturing method and packaging bag - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a packaging bag and the packaging bag.

BACKGROUND ART In recent years, various flexible packaging bags using films or sheets made of thermoplastic resin have been proposed as materials for packaging foods, medicines, metal parts including precision instruments, and the like. Among the items enclosed in the packaging bag, there are items that are vulnerable to humidity and oxygen. When an article having such properties is enclosed, a functional material such as a desiccant, an oxygen absorber, or an anti-rust agent is enclosed in the packaging bag together with the article, depending on the purpose.

For example, particulate substances such as silica gel are commonly used as desiccants. Such granular substances are packed in a bag shape with a moisture-permeable film or a sheet made of paper, and are sealed together with the article in the packaging bag. However, in this method, when the article is taken out of the packaging bag, the desiccant often adheres to the article and is taken out together with the article. In particular, when the article is food, the user is not aware that the desiccant is attached to the food, which easily leads to accidental ingestion or accidental ingestion.

Japanese Utility Model Laid-Open No. 59-87479 JP 2016-113213 A

As in Patent Document 1, there is an example in which a storage bag containing an oxygen absorber is fixed inside a storage bag of an article so that it cannot be taken out together with the article. However, the storage bag containing the oxygen scavenger is inflated by the oxygen scavenger, and it may be difficult to evenly press the periphery of the storage bag. In addition, if the storage bag is fused strongly, the storage bag is likely to be perforated. Depending on the product, the product may be greatly shaken during the process of storage, transportation, and sale, and the adhesion of the storage bag enclosing the oxygen scavenger may come off due to the friction and impact. In addition, it may become difficult to arrange the storage bag at an appropriate position in the fusion process. If the arrangement is misaligned, the sheet of the storage bag will be damaged at the boundary line between the fused and non-fused parts due to excessive pulling of the sheet of the storage bag due to the oxygen absorber getting caught during fusion. Oxygen scavenger sometimes fell into the bag.

Attempts have also been made to form a packaging bag from a film containing zeolite as a moisture absorbing component and a film containing zeolite as a gas adsorbing component, as in Patent Document 2. In this case, since the desiccant is not attached separately, the risk of accidental ingestion is reduced. However, it is difficult to obtain a heat-sealing property with a film simply containing zeolite. If heat sealing is not sufficient, it is difficult to keep the inside of the packaging bag sufficiently airtight. For this reason, the contents enclosed in the packaging bag may become damp, and in the case of metal, rust may occur. In addition, packaging bags are required to have performance such as texture and resistance to tearing.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a packaging bag in which the functional material does not fall in the packaging bag, and which is excellent in airtightness so that the effects of the functional material are less likely to be lost, and to provide a method for manufacturing the same.

The present invention solves the above problems by the following methods. A method for manufacturing a packaging bag in which a functional material is enclosed in a bag body obtained by welding a thermoplastic resin film, wherein the porous film is formed by stretching a resin composition containing a low melting point polyolefin resin and a filler as the functional material. In the process of welding the bag body, the strip is sandwiched between the thermoplastic resin films forming the bag body, a part of the strip is welded to the bag body, and the strip is placed in the packaging bag. It is a manufacturing method of the packaging bag which carries out.

Also, the packaging bag has a bag body composed of a welded thermoplastic film and a functional material enclosed in the bag body, and the functional material is a resin composition containing a low melting point polyolefin resin and a filler. It is a strip-shaped body made of a porous film in a constructed and stretched state, and the strip-shaped body is sandwiched between thermoplastic resin films constituting a bag body and arranged in a packaging bag. .

In the manufacturing method described above, it is preferable to supply the thermoplastic film to the welding step while aligning the longitudinal direction of the strip with the longitudinal direction of the strip.

In the packaging bag and the manufacturing method described above, it is preferable that the strip has a thickness of 10 to 500 μm.

In the above-mentioned packaging bag and the above-mentioned manufacturing method, it is preferable that the belt-shaped body forms voids around the filler, and the plurality of voids are connected to form communicating holes.

According to the present invention, it is possible to provide a packaging bag in which the functional material does not drop in the packaging bag, and which is excellent in airtightness and thus has little loss of the effect of the functional material, and a method for manufacturing the same.

1 is a plan view showing one embodiment of a packaging bag of the present invention; FIG. FIG. 2 is a cross-sectional view in the AA section of FIG. 1; FIG. 4 is a schematic cross-sectional view of a strip; It is the figure which showed typically one Embodiment of the manufacturing method of a packaging bag. 5 is a schematic diagram showing a part of the process shown in FIG. 4 from above; FIG.

An embodiment of the present invention will be described below, but the technical scope of the present invention is not limited to this embodiment, and the configuration can be changed as appropriate according to the type of content to be targeted. can.

An embodiment of the packaging bag of the present invention is shown in FIGS. 1 and 2. FIG. A bag body 1 of the packaging bag is obtained by welding a thermoplastic resin film 2, as shown in FIG. The bag body 1 shown in FIG. 1 has a rectangular shape and is welded on three sides. The functional material in FIG. 1 is a band-shaped porous film made of a resin composition containing a filler, and is enclosed in the bag body 1 in a state where a part of the functional material is welded.

<Thermoplastic resin film>
The thermoplastic resin film used for the bag body is produced, for example, by molding a thermoplastic resin by a known extrusion molding method such as an inflation method or a T-die method. This thermoplastic resin film may be appropriately stretched.

Thermoplastic resins used for thermoplastic resin films include, for example, polyolefins, polyesters, polyamides, and the like. The thermoplastic resin is appropriately selected in consideration of the contents to be put into the bag body, and may be composed of not only a single layer but also multiple layers. These resins may be combined when producing a single-layer or multi-layer thermoplastic resin film. Among them, polyolefin is preferably used for at least the welding surface of the thermoplastic resin film from the viewpoints of low specific gravity, resistance to oil and the like, excellent durability, and good heat sealability. Polyolefins include high-density polyethylene, polypropylene, propylene-ethylene block copolymers, propylene-ethylene random copolymers, and the like. It is particularly preferred to use polyethylene or polypropylene.

<Functional materials>
A functional material is used to obtain a desired function within the packaging bag. For example, a hygroscopic component is added to dry the inside of the packaging bag, or a rust inhibitor is added to prevent the contents from rusting, so that the contents are preserved in an appropriate state. In addition, the porous portion itself of the porous film, which will be described later, also functions as a functional material.

In the packaging bag of this embodiment, as shown in FIG. 3, the belt-shaped body 3 as the functional material includes a low-melting polyolefin resin 31, a filler 32, and voids 33 around the filler 32 (which can be called a porous portion). there is). Examples of the low-melting-point polyolefin resin referred to here include low-density polyethylene, propylene-ethylene random copolymer, low-stereoregular polypropylene, and the like.

The low-melting-point polyethylene resin is, for example, a resin having a melting point of 80 to 125°C in the case of polyolefin mainly composed of polyethylene, and a resin having a melting point of 90 to 150°C in the case of polyolefin mainly composed of polypropylene. exemplified. In general, the low melting point polyolefin resin preferably has a melting point of 80-150°C. The resin used for the strip may have the same melting point as the resin used for the thermoplastic resin film of the bag body as long as it is within the range of the above melting point. It is preferable to use a resin having a lower melting point than the thermoplastic resin used for the main body. As will be described later, it is important to use a low-melting polyolefin resin to achieve high heat sealability. Furthermore, many of low-melting-point polyolefin resins exhibit a low melting point because they are difficult to crystallize, and are difficult to crystallize even when they are stretched. The functional material uses the filler and the voids around it to obtain its function. If the crystallization is too high, it becomes difficult for the components related to the function to pass through the resin, making it difficult to obtain the function. Become. It is preferable to use a low-melting-point polyolefin resin from the viewpoint that the crystallization is suppressed and the function is easily exhibited.

One or more fillers can be selected according to the intended purpose of the filler contained in the belt-like body that serves as the functional material. Fillers include, for example, silica, calcium oxide, calcium chloride, zeolite, molecular sieves, and other hygroscopic materials; or calcium carbonate, talc, mica, zinc carbonate, barium sulfate, titanium oxide, aluminum, and the like. An inorganic filler etc. are mentioned. An inorganic material is preferable from the viewpoint of forming voids, but an organic material may also be used. Various functional ingredients such as rust preventives, insect repellents, bactericides, and aromatics may be added and used together.

For example, the belt-like body that will be the functional material is formed by extrusion molding a resin composition containing a low-melting polyolefin resin and a filler by an inflation method, a T-die method, or the like, and then is stretched to form voids around the filler. It can be formed by forming a formed porous film and then slitting the porous film into narrow widths. The main purpose of the stretching is to create voids around the filler, to incorporate components related to the function of the functional material into the voids, and the like. In addition, since the band-shaped body is stretched, it has excellent tensile strength, is easy to handle during processing, and is less likely to break easily even if friction occurs with the contents after being placed in the packaging bag. Therefore, the risk of accidental ingestion caused by the strip being torn off into the packaging bag can be reduced. From the standpoint of making the belt-shaped body less likely to tear, it is preferable to limit the stretching to uniaxial stretching rather than stretching biaxially. By uniaxially stretching, the strip becomes easier to split in the length direction, but less likely to split in the width direction. If both longitudinal ends of the strip are welded together with the bag body, the strip will almost never fall into the packaging bag.

<Method for manufacturing packaging bag>
One embodiment of the method for manufacturing the packaging bag according to the above embodiment will be described with reference to FIGS. 4 and 5. FIG. FIG. 4 shows an example of a method of manufacturing a packaging bag having the shape shown in FIG. In FIGS. 4 and 5, reference numeral 2 denotes a roll of thermoplastic resin film, and reference numeral 3 denotes a roll of strip. In FIG. 4, the thermoplastic resin film 2, which is the constituent material of the bag body, is supplied from above and below, and the belt-shaped body 3, which is the functional material, is placed between them. there is

In FIG. 4, the longitudinal direction of the thermoplastic resin film 2 and the longitudinal direction of the strip 3 are aligned and continuously supplied to the heat sealing process. When heat-sealing the thermoplastic resin film and the strip, they do not necessarily have to be inserted in the same direction as the flow direction in the manufacturing process, but may be inserted in the direction perpendicular to the flow direction. In that case, the strip may be intermittently delivered and inserted. However, in the method of the present embodiment, since the strip is stretched, the strip is likely to be thermally shrunk. Therefore, in some cases, it is necessary to take measures to prevent the position of the belt-like body from being displaced. As shown in FIG. 4, if the longitudinal direction of the thermoplastic resin film is aligned with the longitudinal direction of the belt-like body and continuously supplied to the heat-sealing process, the position of the belt-like body with respect to the thermoplastic resin film can be maintained even with a simple apparatus. It is preferable because it is possible to reliably weld the belt-shaped body in a state in which the belt-like body is not shifted in the heat-sealing process and wrinkles are hardly generated. When the belt-like body is continuously supplied to the heat-sealing process, the belt-like body is arranged with a length extending over one side of the bag body.

FIG. 5 is a schematic view of the heat-sealing process of FIG. 4 viewed from above. The thermoplastic resin film 2 and strip 3 supplied to the heat-sealing process are welded so that a part of the strip 3 is integrated with the thermoplastic resin film 2 . The first welded portion 4 is a portion where only the thermoplastic resin film 2 is welded, and the second welded portion 5 is a portion where the thermoplastic resin film 2 and the strip 3 are welded. Both the first welded part 4 and the second welded part 5 are welded together by bringing a welding tool such as a hot plate 6 into contact therewith. After the welding is completed, the continuous bag body in which the packaging bags are continuously connected is formed. After the heat sealing process, the thermoplastic resin film 2 is cut along the broken line in the width direction in a cutting process (not shown).

The welding position is arbitrarily selected according to the desired bag shape. For example, side seals, two-side seals, three-side seals, four-side seals, pillow seals, gusset seals, palm-to-arm seals, standing pouches, etc., can be formed into various forms of packaging bags depending on the application.

It is preferable that the strip is inserted in a direction parallel to one side of the thermoplastic resin film in the formed packaging bag. By inserting it in a direction parallel to one side of the thermoplastic resin film, friction with the contents to be enclosed is reduced, and breakage and fall of the strip can be prevented. Although FIG. 1 shows a bag shape with three sides welded together, the upper side is welded after the contents are put in, and finally used as a four-sided sealed package.

The position of the strip in the packaging bag is arbitrarily selected. Since it is a position that does not hinder the opening of the packaging bag and does not hinder the filling of the contents, it is preferable that the belt-shaped body is arranged along the side corresponding to the bottom of the packaging bag as shown in FIG. In particular, when the strip is uniaxially stretched in the longitudinal direction, the longitudinal ends of the strip are welded to the thermoplastic film forming the bag body as shown in FIG. It is less likely to be damaged by an external force from the packaging bag, and there is almost no possibility that the strip will be torn off into the packaging bag.

Welding methods include known methods such as hot plate, hot air, ultrasonic waves, and impulse sealer. An appropriate welding tool may be used according to each technique. For example, hot plate welding, in which heating can be performed with strong pressure, is preferable because high heat sealability and airtightness can be obtained.

In the packaging bag of this embodiment, since the low-melting point polyolefin resin is used for the strip, there is no need to apply welding at a significantly high temperature. The higher the welding temperature, the higher the solubility of the resin, which is advantageous for welding.

One of them is thermal deterioration of thermoplastic resin films. It is generally known that films made of thermoplastic resins are degraded by exposure to high temperatures. A packaging bag formed by welding has a considerable possibility that the welded portion of the film deteriorates and the packaging bag is damaged therefrom.

The second is that a phenomenon called polyballs is likely to occur. When a plurality of layers are integrated by welding, the melted resin protrudes and adheres between the layers at the boundary between the welded portion and the non-welded portion. This is called a plastic ball, and there is a risk that it will be the starting point and cause bag breakage. If the plastic balls come off inside the packaging bag due to friction with the contents of the packaging bag, there is a risk of contamination or accidental ingestion in the case of food applications. This phenomenon is particularly likely to occur when heating while applying pressure.

The third is that the components related to the functionality of the strip are likely to be thermally decomposed. When volatile substances are contained by exposure to high temperature, the components are likely to volatilize, come out to the surface to be welded and intervene in the bonding surface, making it difficult to obtain high adhesive strength.

In the packaging bag of the present embodiment, since the low-melting point polyolefin resin is used for the strip, the probability of occurrence of each of the above problems is reduced.

Normally, the amount of heat required for welding is insufficient to sandwich more between the thermoplastic resin films that form the bag body, and it is necessary to set the temperature higher than that for welding the thermoplastic resin films. If high-temperature welding is not performed, problems such as insufficient heat-sealability and airtightness usually arise. However, in the packaging bag of this embodiment, the problem can be solved by using a porous film made of a low-melting polyolefin resin for the strip. At the time of welding, the thermoplastic resin is in a melted state and has high fluidity. When pressure is further applied by the hot plate 6 in this state, the melted resin enters the porous portion of the belt-shaped body, and the belt-shaped body is strongly welded, and the airtightness of the packaging bag is improved. Since the thicknesses of the first welded portion 4 and the second welded portion 5 are different, a gap is likely to occur at the boundary between the first welded portion 4 and the second welded portion 5. fill in

Welding is performed on a portion of the strip. This is to take advantage of the porous nature of the strip. The porous portion 33 of the belt-like body in FIG. 3 has the function of taking in the component to be removed from the packaging bag into the porous portion or releasing the component carried in the porous portion. If welding is performed, the porous portion is blocked by the dissolved resin as described above, and loses its function as a porous portion. In order to take advantage of the porous characteristics, it is necessary that the portion where the belt-shaped body is not welded is arranged inside the packaging bag.

Furthermore, it is preferable that the porous portion of the belt-like body has a plurality of continuous voids to form communicating pores. In order to more effectively exhibit the function of the porous portion in the non-welded portion, it is advantageous to disperse and stretch the filler to the extent that communicating pores are formed.

For example, when a material having a hygroscopic effect is used as the filler, more moisture in the packaging bag can be absorbed through the communication holes. Not only is the total amount of moisture absorbed large, but the initial moisture absorption speed is high when there are communicating holes. Since the initial moisture absorption rate is high, the humidity inside the packaging bag can be removed before the contents absorb moisture, and the contents can be stored in a dry state.

It is thought that the function of the packaging bag improves as the amount of the filler compounded increases. Here, if there is a communicating hole, the component can also be supported in the communicating hole, so it is possible to blend the filler in an amount exceeding the resin saturation amount. If the filler is a volatile component, the effect of the component slowly released through the communicating holes will last for a long period of time when the belt-shaped body carrying a large amount of the component in the communicating holes is enclosed in the packaging bag. is preferable.

In order to achieve better heat-sealability and airtightness in the packaging bag, the thickness of the strip is preferably 10 to 500 μm. It can be said that a thicker thickness is more advantageous in order to obtain functionality in the functional material. However, if the thickness is too large, it may become difficult for heat to pass through, making welding difficult. In particular, a gap may occur at the boundary between the first welded portion 4 and the second welded portion 5 . Molten resin tends to protrude, and plastic balls may occur. As described above, the packaging bag of this embodiment utilizes the porous function. Therefore, even with a relatively thin thickness, high functionality is exhibited. In addition, by using a porous material, even if pressure is applied during welding, the resin will flow in such a way as to fill the voids, making it less likely to become a plastic ball.

Since the resin that fills the porous portion is the thermoplastic resin film of the welded portion and the band-shaped resin, if there are too many porous portions, it may be difficult to fill all of them with the resin. The ratio of the porous portion is preferably in the range of 20 to 60% per belt-like body enclosed in the packaging bag. In order to achieve this range, the thickness of the strip is preferably 10 to 500 μm. More preferably, it is 50 to 300 μm.

Since the ratio of the porous portion depends on the ratio of the filler contained in the strip, it is preferable to add the filler to the extent that it occupies 20 mass % or more of the mass of the strip. More preferably, it ranges from 40 to 70 mass % of the mass of the strip. By adding the filler within this range, the plurality of voids formed by the stretching can be easily connected.

After the heat-sealing process, the contents are packed before or after the cutting process, and after the contents are packed, one side of the opening is closed to form a package.

The contents to be packed in the packaging bag are not particularly limited, and can be used for packing and wrapping foods, medicines, electronic parts, precision machines, recording materials, and the like.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited only to the following examples.

[Example 1]
(Thermoplastic resin film A)
A commercially available OPP film roll having a thickness of 50 μm was prepared and used as a thermoplastic film A.
(Strip A)
A propylene-ethylene random copolymer (density of 0.900 g/cm ³ , melting point of 135° C.) of 60% by mass and silica (particle size of 3.7 μm) of 40% by mass were mixed to prepare a film using an inflation method. . After the film was shredded, it was uniaxially stretched and annealed, and wound up to obtain a strip A having a width of 15 mm. The thickness of strip A was 110 μm.

(Manufacturing method of packaging bag)
As shown in FIGS. 4 and 5, the strip A is sandwiched between two thermoplastic resin films A with their ends aligned, and supplied to packaging bag manufacturing equipment. In this state, three sides are welded to produce a continuous bag. After that, each bag body was separated in a cutting step to obtain a packaging bag A of the present invention.

[Comparative Example 1]
A packaging bag X was obtained in the same manner as in Example 1, except that the strip A was not used.

[Example 2]
(Thermoplastic film B)
A roll of commercially available polyethylene film having a thickness of 60 μm was prepared and used as a thermoplastic film B.

(Band B)
A mixture of 30% by mass of linear low-density polyethylene (density: 0.932 g/cm ³ , melting point: 123° C.), 60% by mass of calcium carbonate (average particle size: 5 μm), and 10% by mass of an organic amine antirust agent. was made into a film by the T-die method. The resulting film was cut into strips, stretched, annealed, and wound up to obtain a strip B having a width of 17 mm. The thickness of the strip B was 160 µm.

A packaging bag B was obtained by making a bag in the same manner as in Example 1 using the strip B and the thermoplastic resin film B thus obtained.

[Comparative Example 2]
A packaging bag Y was obtained in the same manner as in Example 2, except that instead of the thermoplastic film B, a roll of a commercially available vaporizable rust preventive film was used, and the strip B was not used.

The packaging bag A and the packaging bag X were each filled with fried sweets made of vegetables as contents. Only the packaging bag X was packed with "AGELESS DRY" (registered trademark) (manufactured by Mitsubishi Gas Chemical Company, Inc.) as a package-type desiccant contained in a small bag. This was hermetically sealed to form a package. Each package was stored in a dark place at 25° C. for 7 days. After that, the package was opened, and the flavor of the contents was confirmed. The flavor of the fried confectionery in the packaging bag A was comparable to that of the fried confectionery in the packaging bag X. When taking out the fried sweets from the packaging bag X, the package-type desiccant material came out together with the fried sweets. On the other hand, when taking out the fried snacks from the packaging bag A, only the fried snacks could be taken out because the strip was fixed to the packaging bag.

Metal pieces were enclosed as contents in the packaging bag B and the packaging bag Y, respectively. This was sealed and used as a package. Each package was stored in a dark place at 25° C. for 14 days. After 7 days and 14 days from the start of storage, the package was opened, and the contents were visually observed to check for the presence of rust.

1 bag body 2 thermoplastic resin film 3 strip 31 low-melting point polyolefin resin 32 filler 33 void 4 first welded portion 5 second welded portion 6 hot plate

Claims (5)

A method for manufacturing a packaging bag in which a functional material is enclosed in a bag body obtained by welding a thermoplastic resin film,
Using a strip made of a porous film obtained by stretching a resin composition containing a low melting point polyolefin resin and a filler as a functional material,
In the welding process of the bag body, the belt-shaped body is sandwiched between the thermoplastic resin films forming the bag body, a part of the belt-shaped body is welded to the bag body, and the belt-shaped body is arranged in the packaging bag ,
The low melting point polyolefin resin has a lower melting point than the thermoplastic resin forming the bag body,
The method for manufacturing a packaging bag , wherein the porous film has voids around the filler . 2. The method of manufacturing a packaging bag according to claim 1, wherein the thermoplastic film is supplied to the welding step with the longitudinal direction of the strip being aligned with the longitudinal direction of the strip. The method for manufacturing a packaging bag according to claim 1 or 2, wherein the strip has a thickness of 10 to 500 µm. 4. The method of manufacturing a packaging bag according to any one of claims 1 to 3, wherein the strip forms voids around the filler, and the plurality of voids are connected to form communicating holes. A packaging bag having a bag body composed of a welded thermoplastic film and a functional material enclosed in the bag body,
The functional material is a belt-like body made of a stretched porous film made of a resin composition containing a low melting point polyolefin resin and a filler,
The belt-shaped body is sandwiched between thermoplastic resin films that constitute the bag body, and is arranged in the packaging bag ,
The low melting point polyolefin resin has a lower melting point than the thermoplastic resin forming the bag body,
The packaging bag , wherein the porous film has voids around the filler .

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