JP3681707B2 - Easy-cleavable film, method for producing the same, and bag - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an easily tearable film used for packaging foods, pharmaceuticals and the like, a method for producing the film, and a bag for packaging foods, pharmaceuticals and the like.
[0002]
[Prior art]
A bag made of a polymer sheet material is sometimes used as a packaging material for packaging foods such as liquid soup and powdered soup, and powdered pharmaceuticals. Because the polymer sheet material has high tear strength, it can prevent leakage and scattering of contents due to breakage of the bag during storage and transportation, but it cannot be easily torn when opening the bag. There's a problem.
Therefore, for the purpose of facilitating the tearing of the bag body, easy opening means such as notches and a large number of scratches may be formed in the seal portion at the edge of the bag body. When such an easy-opening means is formed, the tearing strength is reduced and the tearability is improved, so that the bag can be easily opened from any position. Therefore, depending on the direction of the force at the time of tearing, the tearing may not be reliably performed in a predetermined direction. In such a case, the opening formed by the tearing may be smaller than a predetermined size, which may cause problems when taking out the contents of the bag.
[0003]
Then, the method which can cut | disconnect a bag body reliably to a predetermined direction from arbitrary positions is examined.
For example, in Japanese Patent No. 2716352, through-holes or non-through-holes having a specific average opening diameter are heat-fusible on one side of a porous film made of polyester, nylon or oriented polypropylene having a specific density. An easily tearable film in which a polymer film is laminated has been proposed. And it is supposed that the bag body produced from this easily tearable film can cut | disconnect a bag body reliably in a predetermined direction from arbitrary positions.
[0004]
[Problems to be solved by the invention]
However, in the easily tearable film described in Japanese Patent No. 2716352, it can be surely torn in a predetermined direction from an arbitrary position. However, since a through hole or a non-through hole is formed on the entire exposed film surface, When the fusible polymer film is broken, the contents may leak through the through hole or the non-through hole. In addition, since a through-hole or non-through-hole is formed in a film that has an excellent gas barrier property, the gas permeability of oxygen, water vapor, etc. increases, and the contents of the bag may be altered. It was.
In addition, if through holes or non-through holes are formed in the exposed film surface layer, the surface layer becomes uneven, and the surface of the delivery roll and the film are in uniform contact when the film is delivered by a delivery roll or the like. Otherwise, the film may meander and be sent out. When such meandering occurs, the film is displaced from a predetermined position, and when filling and packaging using this film, the filling and packaging may be defective or the productivity of filling and packaging may be reduced.
[0005]
The present invention has been made in view of the above circumstances, and can easily cut in a predetermined direction from an arbitrary position, and also maintains easy gas barrier properties and has high productivity in filling and packaging. An object of the present invention is to provide an adhesive film, a method for producing the same, and a bag formed from the easily tearable film.
[0006]
[Means for Solving the Problems]
As a result of studies to solve the above problems, the present inventors have invented the following easily tearable film and a method for producing the film.
That is, the easy-cleavable film of the present invention has a base material, an intermediate layer formed on the base material by extrusion-laminating polyethylene, and an easy-cut film formed on the intermediate layer. A tearable film, wherein the intermediate layer has a number of through holes and / or non-through holes.
When a large number of through holes and / or non-through holes are formed in the intermediate layer of the film having a base material, an intermediate layer, and a sealant layer, the through holes and non-through holes are formed when the film is torn from the edge portion Therefore, the tearability is improved, and it is possible to surely cut in a predetermined direction from an arbitrary position.
Moreover, although the through-hole and / or the non-through-hole are formed in the intermediate layer, since it is not necessary to provide a thin portion or hole in the base material, the gas barrier property does not deteriorate.
Moreover, since the sealant layer is formed on the intermediate layer that forms the through holes and / or the non-through holes, the surface layer of the easy-cleavable film finally obtained is smooth, and the film is fed by a delivery roll or the like. When doing so, the surface of the delivery roll and the film can be in uniform contact. Therefore, the film does not meander and are sent out, and when filling and packaging after delivery, the film does not deviate from a predetermined position and does not cause defects in the filling and packaging, thereby improving the productivity of filling and packaging.
[0007]
The easy-cleavable film manufacturing method of the present invention includes a first laminating step for laminating a base material and an intermediate layer, and a hole for forming a through hole and / or a non-through hole in the intermediate layer after the first laminating step. And a second laminating step of laminating a sealant layer on a surface of the intermediate layer on which the base material is not laminated after the hole forming step, and the first laminating step is performed on the base material. An intermediate layer made of polyethylene is formed by an extrusion laminating method.
According to such a manufacturing method, lamination of each layer and formation of a through hole and / or a non-through hole can be continuously performed, which is efficient.
[0008]
Moreover, in the manufacturing method of the easily-cleavable film of this invention, it is preferable to form the said through-hole and / or a non-through-hole by a drilling in the said hole formation process.
When the through hole and / or the non-through hole is formed by drilling, not only the formation of the through hole and / or the non-through hole is efficient, but the shape of the through hole and / or the non-through hole is not disturbed, Since the direction of tearing is stable, an easily tearable film with better tearability can be provided.
[0009]
In addition, since the bag of the present invention is formed from the above-described easily-cleavable film, when opening the bag, it can be surely torn in a predetermined direction from any position. The gas barrier property is also maintained and the contents of the bag are not altered.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
First, one embodiment of the easily tearable film of the present invention will be described with reference to a cross-sectional view of the easily tearable film 1a shown in FIG.
The easy-cleavable film 1 a of this embodiment includes a base material 11, an intermediate layer 12, and a sealant layer 13, and through holes 14 are formed in the intermediate layer 12.
[0011]
The substrate 11 is not particularly limited as long as it has a high mechanical strength and has a gas barrier property such as oxygen and water vapor, and examples thereof include polyamide such as nylon, polyester, and oriented polypropylene. Among these, polyamide is preferable because of its high mechanical strength and excellent gas barrier properties. In this example, the base material 11 is formed of a single layer, but may be formed of multiple layers made of a plurality of different materials.
The thickness of the substrate 11 is preferably 10 to 30 μm. If the thickness is less than 10 μm, the strength of the easily-cleavable film 1a finally obtained is weakened and may be torn even at times other than opening. Moreover, gas barrier property falls and possibility that the content packaged with this easily tearable film 1a will change in quality arises. On the other hand, when it exceeds 30 μm, the rigidity of the easy-cleavable film 1a finally obtained is increased, and the handleability may be deteriorated. Also, the cost increases.
[0012]
The intermediate layer 12 is a layer disposed between the base material 11 and the sealant layer 13, and a plurality of through holes 14 are formed in the intermediate layer 12.
The material used for the intermediate layer 12, polyethylene and the like, among, formed ease of through holes 14, preferably low-density polyethylene ease of laminate with the substrate 11.
The thickness of the intermediate layer 12 is preferably 10 to 30 μm. If it is less than 10 μm, there is a possibility that the effect of improving the tearability due to the formation of the through hole 14 is not sufficiently exhibited. On the other hand, if it exceeds 30 μm, the cost increases and the easy tearability may not be sufficiently improved. In addition, the intermediate layer 12 is a single layer in this example, but may be formed of multiple layers made of a plurality of different materials as long as it is polyethylene .
[0013]
Although the outer diameter of the through-hole 14 formed here can be set as appropriate, it is preferably 0.5 to 100 μm. When the outer diameter is less than 0.5 μm, the tearability of the easy-cleavable film 1a obtained cannot be sufficiently improved, and as a result, there is a case where it is not possible to reliably tear in a predetermined direction from any position. Arise. On the other hand, if it exceeds 100 μm, the direction of the tear may not be stable and may not tear in the desired direction. If the outer diameter is large, depending on the method for producing the easily tearable film 1a, an adhesive used when the sealant layer 13 is bonded to the intermediate layer 12 or a heat-softened sealant layer 13 may penetrate this penetration layer. There is a possibility of entering the hole 14 and closing the through hole 14.
Moreover, the formation density of the through-holes 14 can be appropriately set according to the outer diameter thereof, but is preferably 1000 to 5000 pieces / cm ² . If the formation density is less than 1000 pieces / cm ² , the tearability of the easily tearable film 1a obtained may not be sufficiently improved. On the other hand, if it exceeds 5000 pieces / cm ² , the strength of the intermediate layer 12 may be reduced, or the outer diameter of the through hole 14 needs to be reduced in order to prevent such strength reduction.
[0014]
The sealant layer 13 is formed on the intermediate layer 12, and is the outermost layer in the easily tearable film 1a of this example.
The material used for the sealant layer 13 is not particularly limited as long as it covers the intermediate layer 12 and functions as a sealant, and examples thereof include polyolefins such as polyethylene and polypropylene. Among these, low density polyethylene is preferable from the viewpoint of easy lamination with the intermediate layer 12.
The thickness of the sealant layer 13 is preferably 20 to 50 μm. If it is less than 20 μm, the strength when the easily tearable film 1a obtained is used as a packaging material is lowered. On the other hand, when the thickness exceeds 50 μm, the extrusion laminating method may not be adopted when the sealant layer 13 is laminated on the intermediate layer 12. The sealant layer 13 in this example is a single layer, but may be a multilayer made of a plurality of different materials.
[0015]
Each of the base material 11, the intermediate layer 12, and the sealant layer 13 may be blended with additives such as an antioxidant, a dye, a pigment, a stabilizer, a filler, and an antistatic agent as necessary. .
[0016]
In such an easy-cleavable film 1a, a large number of through holes 14 are formed in the intermediate layer 12, and when the easy-cleavable film 1a is torn from its edge, it is cut along the through-holes 14. Therefore, the tearability is improved, and it is possible to surely tear from an arbitrary position in a predetermined direction.
Moreover, since the through-hole 14 is formed in the intermediate layer 12, and it is not necessary to make the thickness of the base material 11 partly thin or to form a hole, the gas barrier property of the base material 11 is provided. The easy-cleavable film 1a finally obtained also has gas barrier properties.
Moreover, since the sealant layer 13 is formed on the intermediate layer 12 in which the through-holes 14 are formed, the surface layer of the easily tearable film 1a finally obtained is smooth, and the easily tearable film 1a is delivered. When feeding by a roll or the like, the meandering of the film due to non-uniform contact between the roll surface of the delivery roll and the film does not occur. For this reason, when filling and packaging after delivery, the product does not shift from a predetermined position or cause a defect in the filling and packaging, and the productivity of the filling and packaging is not affected.
[0017]
In addition, an easily tearable film is not limited to embodiment mentioned above. For example, as shown in FIG. 2, a through hole 14 may be formed in the intermediate layer 12, and a non-through hole 15 communicating with the through hole 14 may be formed in the base material 11. In the production of the easy-cleavable film 1b of such a form, as will be described in detail later, a needle or the like used for punching the intermediate layer 12 penetrates the intermediate layer 12 and further reaches the base material 11. However, since it is not necessary to strictly control the depth of the drilling, the formation of the through hole 14 is easy and efficient. However, even in this case, it is preferable that the depth of the non-through hole 15 formed in the base material 11 is a level that does not affect the gas barrier property of the base material 11.
Moreover, as long as it forms in the depth which can improve the tearability of an easily tearable film, the hole formed in the intermediate | middle layer 12 may be the non-through-hole 16 as shown in FIG. Thus, even in the case of the easy-cleavable film 1c in which the hole is the non-through hole 16, it is not necessary to make the depth of the hole exactly match the thickness of the intermediate layer 12, so that the non-through hole 16 can be easily formed. And become efficient.
[0018]
Next, an embodiment of a method for producing the easily tearable film 1a of FIG. 1 will be described with reference to FIGS. Here, FIG. 4 is a diagram schematically showing the overall configuration of the easily tearable film manufacturing apparatus used in the method of manufacturing the easily tearable film 1a of FIG. 1, and FIG. 3 is an enlarged view of a punching means 24. FIG.
[0019]
The easily tearable film manufacturing apparatus of this example includes an intermediate layer extruder 22 that forms an intermediate layer 12 on the base material 11 fed from the base material 21 by an extrusion laminating method, and the intermediate layer 12 and the base material 11. Are pressed from both sides, punching means 24 for punching the intermediate layer 12 from the exposed surface side, and sealant layer extrusion for forming the sealant layer 13 on the punched intermediate layer 12 by extrusion lamination. A roll press 27a, 27b that presses the laminated body of the base material 11, the intermediate layer 12, and the sealant layer 13 from both sides, and a winding that winds up the easily tearable film 1a thus obtained. And a roll 28.
[0020]
When manufacturing the easy-cleavable film 1a using this manufacturing apparatus, first, the base material 11 is sent out from the base material 21, and the intermediate layer 12 made of polyethylene is used for the intermediate layer on the base material 11. A first laminating process is performed in which the base material 11 and the intermediate layer 12 are pressed and laminated with a roll press composed of two rolls 23a and 23b.
Next, a hole forming step is performed in which the intermediate layer 12 is drilled using the punching means 24 to form the through holes 14 from the side of the intermediate layer 12 where the base material 11 is not bonded.
Next, the material forming the sealant layer 13 is extruded and laminated into a film shape by the sealant layer extruder 26 on the surface of the intermediate layer 12 where the substrate 11 is not bonded, and then the substrate 11 and the intermediate layer 12 are laminated. And a sealant layer 13 are subjected to a second laminating step of pressing the laminate from both sides with a roll press composed of two rolls 27a and 27b.
In this way, an easily tearable film 1 a composed of the base material 11, the intermediate layer 12, and the sealant layer 13 is formed, and this is wound up by the winding roll 28.
[0021]
Here, when the through hole 14 is formed in the intermediate layer 12, a punching means 24 as shown in an enlarged view in FIG. 5 is used. The perforating means 24 includes a perforating roller 32 having a heated needle 31 on the outer peripheral surface and a roller 33 that supports the film being perforated from below, and the perforating roller 32 and the roller 33 rotate in opposite directions. The film in which the intermediate layer 12 is laminated on the base material 11 passes between them. At this time, the through hole 14 can be formed in the intermediate layer 12 by disposing the intermediate layer 12 on the perforation roller 32 side and disposing the base material 11 on the roller 33 side.
The temperature of the needle 31 when drilling is not particularly limited, and may be set according to the material of the intermediate layer 12, the temperature of the intermediate layer 12 at that time, and the like. That is, when the intermediate layer 12 has residual heat derived from the first laminating step, the needle 31 does not necessarily have to be heated, and may be at room temperature. Such a method is preferable because it is not necessary to heat the needle 31 and is efficient, and it is easy to form the through-hole 14 having a certain size. On the other hand, if the heating temperature of the needle 31 is too high, a region melted by the needle 31 is widened, and the through hole 14 larger than the outer diameter of the target hole may be formed.
Moreover, the through-hole 14 is formed in the intermediate | middle layer 12 like FIG. 1, and the easily tearable film 1a of the form by which the non-through-hole connected with this through-hole 14 is not formed in the base material 11 is formed When doing so, it is necessary to control the depth when the needle 13 perforates according to the thickness of the intermediate layer 12.
[0022]
In the second laminating step, it is preferable to adjust the pressures of the roll presses 27a and 27b and the laminating speed so that the sealant layer 13 is not softened and pushed into the through holes 14.
[0023]
In the manufacturing method of such an easily tearable film 1a, a first laminating step of laminating the base material 11 and the intermediate layer 12, and then a hole forming step of forming the through hole 14 in the intermediate layer 12, Next, since it has a second laminating step of laminating the sealant layer 13 on the surface of the intermediate layer 12 on which the base material 11 is not bonded, the laminating of the layers 11, 12, 13 and the formation of the through holes Is continuous and efficient.
Further, when the first laminating step and the second laminating step are performed by the extrusion laminating method as shown in FIG. 4, the easily tearable film 1a can be easily formed by simply incorporating the hole forming step into the conventional extrusion laminating step. It can be manufactured and is very efficient.
Further, when the hole forming step is performed by drilling, not only the formation of the through-holes 14 is efficient, but also the hole shape is not disturbed and the direction of the tear is stabilized. A tearable film 1a can be provided.
[0024]
Further, for the easily tearable films 1b and 1c in the form of FIGS. 2 and 3, the production apparatus shown in FIG. 4 is used in the same manner as in the case of producing the easily tearable film 1a in the form of FIG. Thus, it can be manufactured by adjusting the depth when the needle 13 is perforated.
[0025]
As a method for producing easily switching tearable films 1a, 1b, and 1c, without being limited to the aforementioned method, for example, it may be performed second laminating step Ri by the heat lamination method or a dry lamination method. Also, in the hole forming step, the through hole 14 is formed by forming an intermediate layer having a reduced tensile breaking strength by blending a filler, for example, by blending a filler, and by extending the hole. The method of doing etc. may be used.
[0026]
There is no restriction | limiting in particular in the use of the easily cuttable film 1a, 1b, 1c obtained in this way, Although it can use suitably for the various uses by which the improvement of cutability is calculated | required, this easily cuttable film 1a, 1b, 1c By forming the bag body by a method such as heat sealing the edge, the tearability when opening the bag body is excellent, and the gas barrier property is maintained and the contents are altered. In particular, it is possible to provide a bag suitable as a packaging bag for foods and pharmaceuticals.
[0027]
【The invention's effect】
As described above, the easy-cleavable film of the present invention can be reliably torn in a predetermined direction from an arbitrary position, maintains a gas barrier property, and is excellent in productivity at the time of filling and packaging. A bag formed from such an easily tearable film not only has excellent tearability, but also maintains gas barrier properties and does not alter the contents. Useful as a bag. Moreover, according to the production method of the present invention, the excellent easily tearable film as described above can be produced very efficiently.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of an easily tearable film of the present invention.
FIG. 2 is a cross-sectional view showing another embodiment of the easily tearable film of the present invention.
FIG. 3 is a cross-sectional view showing still another embodiment of the easy-cleavable film of the present invention.
FIG. 4 is a diagram schematically showing an example of the overall configuration of an easily tearable film manufacturing apparatus used in the method of manufacturing an easily tearable film of the present invention.
5 is an enlarged view of a punching means in the easy-cleavable film manufacturing apparatus of FIG. 4. FIG.
[Explanation of symbols]
1a, 1b, 1c ... easily tearable film,
11 ... Base material, 12 ... Intermediate layer, 13 ... Sealant layer,
14 ... through hole, 15, 16 ... non-through hole

Claims (6)

An easily tearable film having a base material, an intermediate layer formed on the base material by extrusion-laminating polyethylene , and a sealant layer formed on the intermediate layer,
The easily tearable film, wherein a number of through holes and / or non-through holes are formed in the intermediate layer.   The easily tearable film according to claim 1, wherein when the through hole is formed in the intermediate layer, the base material is formed with a non-through hole communicating with the through hole. A first laminating step of laminating the base material and the intermediate layer; a hole forming step of forming through holes and / or non-through holes in the intermediate layer after the first laminating step; and A second laminating step of laminating a sealant layer on the surface on which the base material is not laminated,
In the first laminating step, an intermediate layer made of polyethylene is formed on a base material by an extrusion laminating method. The said hole formation process forms the said through-hole and / or a non-through-hole by perforation, The manufacturing method of the easily tearable film of Claim 3 characterized by the above-mentioned. 5. The easy cutting according to claim 3, wherein the second laminating step is to form a sealant layer on the surface of the intermediate layer on which the base material is not laminated by an extrusion laminating method. A method for producing a tearable film. A bag formed from the easy-cleavable film according to claim 1 .

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