JP4954396B2 - Method for forming easy-opening means and method for manufacturing pouch with easy-opening means formed - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming easy-opening means for forming easy-opening means on a bag and a method for manufacturing a pouch having easy-opening means formed by the method .
[0002]
[Prior art]
A bag body such as a refill pouch may be provided with a notch as an easy-opening means so that it can be easily opened by hand without using a tool such as scissors. Examples of the shape of the notch include an I shape, a base shape, a U shape, and a V shape. Such a notch is formed using a blade shape having a desired shape.
[0003]
[Problems to be solved by the invention]
However, when the notch is formed by using the blade mold, punching waste is generated and adheres to the bag, and it takes time to remove it. Further, there is a problem that punching scraps adhere to the blade mold, and the work of polishing the blade mold and the management of the blade mold are complicated, resulting in a decrease in workability.
In addition, as an easy-opening means, an opening assist line formed by scratching the opening direction or providing a perforation may be provided. When the opening assisting line and the notch are used in combination, the opening assisting line and the notch forming position may be separated from each other because they are formed in separate steps. If the end portion of the opening assist line and the notch forming position are separated from each other, the tear opening line may not be split along the opening assist line. In such a case, the effect of combining the notch and the opening assist line is not exhibited, and there is a problem that the tear strength in the opening means cannot be stably lowered.
[0004]
The present invention has been made in view of the above circumstances, and even when a method for forming easy-opening means that does not use a blade mold, and even when a notch and an opening assisting line are provided, each can be separated. It is an object of the present invention to provide a method for forming no easy opening means and a method for manufacturing a pouch provided with easy opening means by this method.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to solve the above-mentioned problems, the present inventors have, for example, a resin layer and a laser that are difficult to absorb a laser, such as a laminate composed of a polyolefin resin layer and a resin layer other than a polyolefin resin. In a bag body using a laminate composed of a resin layer that is easy to absorb, conventionally, the laser light passes through a resin having a low absorption rate in the wavelength region of the laser light, such as a polyolefin resin, for example. Contrary to the common knowledge that a polyolefin resin layer cannot be cut with a laser beam, the inventors have obtained the knowledge that a notch can be formed by cutting with a laser beam.
The reason why the notch can be formed by cutting with laser light is not clear, but heat generation caused by laser light slightly absorbed by the polyolefin resin layer and other than polyolefin resin laminated on the polyolefin resin layer It is considered that the polyolefin resin is melted in cooperation with the heat propagated by the heat generated in the resin layer. In addition, since the notch exists in the seal portion and is located at the end of the bag body, the melted polyolefin resin is the surface of the groove formed by volatilization of the resin other than the polyolefin resin by the laser beam. It is thought that it volatilizes not only from the end but also from the end of the seal part. In this way, the scratch formed at the end of the seal portion functions as a notch.
[0006]
That is, in the method of forming easy-opening means of the present invention, the laminate of the bag body in which a laminate comprising a resin layer that hardly absorbs a laser and a resin layer that easily absorbs a laser is used at least in a portion where a notch is formed. The surface of the resin layer is irradiated with a laser to form a shallow groove in the resin layer that easily absorbs the laser, and then the laser is irradiated while reciprocatingly scanning on the groove to form the resin layer that easily absorbs the laser. It is characterized by having a notch forming step of forming a notch by deepening a groove on the resin layer which is difficult to absorb the laser exposed below .
Here, the “resin layer that hardly absorbs laser” refers to a resin layer that does not scratch or evaporate on the surface of the film even when irradiated with laser under the following conditions. The conditions are a carbon dioxide laser with a frequency of 4 to 6 kHz and a scan speed of 600 to 1000 mm / sec. Further, the “resin layer that easily absorbs laser” refers to a resin layer that is scratched or evaporated on the surface of the film when irradiated with laser under the following conditions. The conditions are a carbon dioxide laser with a frequency of 4 to 4.5 kHz and a scan speed of 700 to 800 mm / sec. As such a bag, for example, a laminate in which the resin layer that hardly absorbs the laser is a polyolefin resin layer single film and the resin layer that easily absorbs the laser is a resin layer other than the polyolefin resin is used. Can be mentioned. Furthermore, as the polyolefin resin, polypropylene (PP), polyethylene (PE), ethylene-vinyl acetate copolymer (EVA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl acrylate copolymer (EMA) ), And examples of the resin other than the polyolefin-based resin include nylon, polyethylene terephthalate (PET), and ethylene-vinyl alcohol copolymer (EVOH).
And when forming a notch in a bag body, it is preferable to further irradiate a laser to the said bag body, and to have the opening auxiliary line formation process which forms the opening auxiliary line continuous to the said notch. The resin layer other than the polyolefin resin is preferably a polyester resin layer and / or a polyamide resin layer. Moreover, the manufacturing method of the pouch of this invention forms an easy opening means by the formation method of the easy opening means mentioned above.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
One embodiment of the method for forming easy-opening means of the present invention will be described with reference to FIGS.
The present embodiment is a method of forming an easy-opening means comprising a notch and an opening assist line in a refilling pouch, and the refilling pouch used has a shape as shown in FIG. It is what you have. As shown in FIG. 2, the spout 2 of the refilling pouch 1 is a seal portion 3a, 3b whose end edge is thermally welded, and an unsealed portion 4 is between the seal portions 3a, 3b.
The sheet used for the refilling pouch has an outer layer made of a nylon (6-nylon) layer having a thickness of 25 μm as a base resin layer that easily absorbs a laser, and a thickness of 150 μm as a sealant resin layer that hardly absorbs a laser. It is a laminated body with the inner layer which consists of a linear low density polyethylene (LLDPE) layer.
[0008]
In the method for forming easy-opening means of the present embodiment, the laser 5 is irradiated from the surface of the sealing portion 3a of the spout 2 of the refilling pouch 1 while scanning the surface several times to form a linear notch. A notch forming step, an opening assisting line forming step of irradiating the unsealed portion 4 from the surface while scanning the unsealed portion 4 once or a plurality of times to form an opening assisting line continuous with the notch, and the other of the spout 2 A laser 5 is irradiated from the surface while scanning the surface 3a a plurality of times, and a notch forming step for forming a linear notch continuous with the opening assist line is continuously performed.
The laser 5 used is a carbon dioxide gas laser. The carbon dioxide laser can easily melt polyamide resins such as nylon and polyester resins such as polyethylene terephthalate. On the other hand, polyolefin resins such as linear low-density polyethylene and polypropylene are difficult to absorb a carbon dioxide laser, but as described above, the laser transmittance is not 100%, so they absorb energy, generate heat, and are cut. be able to.
[0009]
Hereinafter, the embodiment will be described in more detail with reference to FIG.
First, as shown in FIG. 3a, the surface of the refilling pouch is irradiated from the extreme end of the surface of the seal portion 3a while scanning the laser 5 in one direction. When the laser 5 is irradiated in this way, the nylon layer is melted by the energy of the laser 5 and evaporated to form a shallow groove.
Next, as shown in FIG. 3b, the scanning direction of the laser 5 is reversed before the entire seal portion 3a is scanned.
[0010]
Next, the laser 5 is irradiated while scanning toward the outermost end of the seal portion 3a, and the laser 5 is irradiated onto the groove formed as described above to increase the depth of the groove. Then, as shown in FIG. 3c, when the end of the seal portion 3a is reached again, the scanning direction of the laser 5 is reversed. At a relatively early stage of the process so far (usually one laser scan), the nylon layer is cut and an LLDPE layer that is hardly melted by the laser 5 is exposed.
In this way, laser irradiation is performed while reciprocally scanning to deepen the groove on the exposed LLDPE layer little by little. At this time, the LLDPE layer is decomposed and vaporized by heat generated when the nylon layer is melted and heat generated by laser irradiation. However, it is considered that the LLDPE layer is also decomposed and vaporized from the end of the seal portion 3a. Therefore, the notch is formed from the end of the seal portion 3a and gradually grows. Finally, a linear notch having a predetermined length is formed.
[0011]
Subsequently, as shown in FIG. 3d, the remaining part of the seal part and the unsealed part 4 are irradiated with laser while scanning the laser 5 in the same direction as the scanning direction of the laser 5 described above, thereby assisting in opening. Form a line. Normally, this scanning is sufficient once in one direction, but scanning may be performed a plurality of times within a range where the opening assist line becomes too deep and the strength of the sheet of the unsealed portion 4 is not insufficient.
[0012]
Subsequently, the laser 5 is scanned continuously up to the end of the other seal portion 3b. When scanning to the extreme end of the seal portion 3b, the scanning direction is reversed as shown in FIG. 3E, and the previously formed groove is irradiated with the laser 5. Then, as shown in FIG. 3f, the scanning direction of the laser 5 is reversed before the entire seal portion 3b is scanned.
Thus, by irradiating the laser while reciprocally scanning with the seal portion 3b, the depth of the groove is increased, and finally a notch having a linear shape is formed.
[0013]
In the above-described embodiment, the laser is not particularly limited as long as a notch is formed by the seal portions 3a and 3b and an opening assist line can be formed by the unsealed portion 4, but the output of the laser 5 may be 3 to 100W. preferable. If it is less than 3 W, it may take a long time to form the notch, and if it exceeds 100 W, the laser device may be expensive.
[0014]
The number of times the laser 5 is reciprocated at the seal portion is arbitrary, but it is preferably set to 3 to 10 times according to the output of the laser and the bag making speed. If the notch is set to be formed less than 3 times, the laser output must be increased, so that a part of the polyolefin-based resin layer of the unsealed portion 4 evaporates, and the sheet strength may be reduced. If the setting is made so that the notch is formed more than 10 times, the laser output must be lowered, so that the opening assist line may not be formed depending on the laser output.
Further, the scanning speed of the laser 5 may be determined as appropriate in consideration of the output of the laser.
[0015]
There is no particular limitation on the method for producing the laminate of the nylon layer and the linear low-density polyethylene layer in the above-described embodiment, for example, wet lamination method, dry lamination method, solventless dry lamination method, extrusion lamination method. The co-extrusion lamination method can be mentioned.
Further, the thickness of the LLDPE layer is not particularly limited, and may be a range usually used for a packaging bag. Usually, the thickness of the LLDPE layer used for a packaging bag is about 10-200 micrometers. Similarly, the thickness of the nylon layer is about 10 to 30 μm.
[0016]
The viscosity of the filling liquid filled in the refilling pouch is 1000 cP or less, preferably 500 cP or less, and more preferably 250 cP or less.
[0017]
In the above-described embodiment, the laser 5 is radiated while reciprocally scanning the seal portions 3a and 3b to form a linear notch, and the laser 5 is applied to the unsealed portion 4. Irradiation is performed while scanning in one direction once or a plurality of times to continuously perform an opening assist line forming step for forming an opening assist line, and a notch and an opening assist line are continuously formed. Therefore, a blade mold is not used for forming the notch, and punching waste does not adhere to the bag body or the blade mold.
In addition, since the end of the opening assisting line coincides with the formation position of the notch and the notch and the opening assisting line are not separated from each other, when the spout 2 is cut and opened, the opening is opened from the notch along the opening assisting line. And the tear strength of the easy-opening means can be stably lowered.
[0018]
In the above-described embodiment, as the resin layer other than the polyolefin-based resin such as the low-density polyethylene resin, a nylon layer which is a kind of polyamide-based resin is used. Excellent toughness, flex resistance, puncture resistance, impact resistance, wear resistance, cold resistance, heat resistance, chemical resistance, etc.
[0019]
In the above-described embodiment, the laser 5 is irradiated only from one direction from the front surface, but may be irradiated from two directions of the front surface and the back surface. In that case, one laser light source may be divided using a mirror or a prism, or a position sensor such as a CCD camera or a photoelectric tube may be provided so that the laser irradiation positions on the front surface and the back surface do not shift. preferable.
Further, in the above-described embodiment, the notch is formed in the order of the notch forming step, the opening assisting line forming step, and the notch forming step, and the sealing portions 3a and 3b at both ends of the spout are formed. The line forming process may be performed continuously, and a notch may be formed only at the seal part at one end of the spout, or the notch forming process may be performed continuously after the opening assist line forming process to seal one of the spouts. You may form a notch only in a part.
[0020]
In the above-described embodiment, the refilling pouch 1 has a shape as shown in FIG. 1, but the present invention is not limited thereto. Further, the direction of the opening assist line is not particularly limited. For example, in a bag body having a rectangular side surface, an opening assist line may be provided so as to cut out the corners of the rectangle. An opening assist line may be provided so as to cut off the upper part.
The refill pouch 1 uses a laminate composed of a base resin layer made of 6-nylon that easily absorbs a laser and a sealant resin layer made of LLDPE that hardly absorbs a laser. Not. For example, instead of 6-nylon, 6,6-nylon, 12-nylon, MXD-6 nylon, and polyamide resins other than nylon may be used for the base resin layer that easily absorbs laser, or polyethylene. Polyester resins such as terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN) may be used. Further, a plurality of these resins may be laminated or mixed.
[0021]
In addition, when polyethylene terephthalate (PET) is used instead of nylon, there is no difference from a normal packaging bag, and the thickness of the PET layer is about 10 to 40 μm. Even when a plurality of layers of nylon or PET are used as the resin other than the polyolefin-based resin, these resins can be easily cut with a laser and can be cut with a normal laser. If the laser output is insufficient, the number of scans may be increased.
[0022]
In addition, other polyolefin resins may be used instead of the LLDPE layer for the sealant resin layer that hardly absorbs laser. The other polyolefin-based resin is a layer made of a resin obtained by homopolymerizing an olefinic structural unit such as ethylene or propylene or copolymerizing with another structural unit, for example, other low density polyethylene, Medium density polyethylene, high density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), ethylene-methacrylic acid copolymer (EMMA), ethylene-methyl acrylate copolymer (EMA) And ethylene-ethyl acrylate copolymer (EEA).
Note that when polypropylene (PP) is used instead of LLDPE, the number of scans and the laser output may be adjusted in the same manner as LLDPE. And the thickness of PP layer does not differ from a normal packaging bag, and is about 10-150 micrometers.
In the present invention, the resin type is selected according to the required quality such as the type of the pouch contents and the appearance as a product, and the thickness is determined. In addition, the laminate used in the present invention includes a resin layer that easily absorbs laser, a gas barrier resin layer such as an ethylene / vinyl alcohol copolymer, an acrylic resin, and a vinylidene chloride resin, a metal oxide vapor deposition layer, and a printing layer. The layer which can provide the function of may be included.
[0023]
Also, the type of laser is not limited to a carbon dioxide laser, and a gas laser other than a carbon dioxide laser, a solid-state laser such as a YAG laser, and a semiconductor laser can be used as appropriate depending on the material used for the pouch.
[0024]
【Effect of the invention】
According to the method for forming easy-opening means of the present invention, since the blade mold is not used for forming the notch, the workability of forming the notch is improved. In addition, since the end of the opening assisting line and the formation position of the notch can be made to coincide with each other, when the spout is cut and opened, it can be easily opened along the opening assisting line from the notch. The tear strength of the opening means can be stably lowered.
Further, the pouch of the present invention has a stable and low tear strength of the easy-opening means, so that it does not bother the opening.
[Brief description of the drawings]
FIG. 1 is a top view of a refilling pouch used in an embodiment according to a method for forming easy-opening means of the present invention.
2 is a cross-sectional view taken along line AA of the refilling pouch shown in FIG. 1. FIG.
FIG. 3 is a cross-sectional view illustrating an embodiment according to a method for forming easy-opening means of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pouch for refill 2 Spout 3a, 3b Seal part 4 Unseal part 5 Laser

Claims (5)

At least the part where the notch is formed absorbs the laser by irradiating the surface of the laminated body of the bag body using a laminated body composed of a resin layer that hardly absorbs laser and a resin layer that easily absorbs laser. After forming a shallow groove in the resin layer that is easy to be radiated, a laser beam is irradiated while scanning back and forth on the groove, and the resin layer that is exposed under the resin layer that easily absorbs the laser is difficult to absorb the laser A method for forming easy-opening means, comprising a step of forming a notch by deepening the upper groove little by little . The bag body is a laminate formed of a polyolefin resin layer that is a resin layer that hardly absorbs the laser and a resin layer other than a polyolefin resin that is a resin layer that easily absorbs the laser , at least in a portion where a notch is formed. The method for forming easy-opening means according to claim 1 , wherein the bag is a bag body. The method for forming easy-opening means according to claim 2 , wherein the resin layer other than the polyolefin-based resin is a polyester-based resin layer and / or a polyamide-based resin layer. The easy-opening means according to any one of claims 1 to 3 , further comprising an opening assisting line forming step of forming an opening assisting line continuous to the notch by further irradiating the bag with a laser. Forming method. An easy-opening means is formed by the easy-opening means forming method according to any one of claims 1 to 4 .

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