JP4797671B2 - Easy tear packaging material and easy-open packaging bag using the same - Google Patents

Description

  The present invention relates to a packaging bag for subdividing products of various types and shapes such as foods, medicines, small items, liquids, powders, pastes, solids, and the like, and a packaging material used for the packaging bag.

  Sheets with a laminated structure of resin and other materials such as resin and aluminum foil, paper, etc. are lightweight and have excellent airtightness, high strength and convenient handling, and particularly require an adhesive to seal However, since it is sufficient to simply heat-seal it, it is used in packaging bags that divide products of various types and shapes such as foods, medicines, small items, liquids, powders, pastes, solids, and the like.

  The packaging materials for these small packaging bags are tough, but once scratched, the scratches tend to propagate. Therefore, the wound of the packaging material is scratched in one place in advance, and this is used as the tear. When pulled, it can be opened easily with the finger. Therefore, a notch that is a notch or a V-shaped notch is provided in advance at the edge of the packaging material at the welded site (see Patent Document 1).

Various other easy-open packaging bags have been proposed. For example, Patent Document 2 discloses an easy-peel packaging bag that is opened using a non-sealed portion as a clue. Patent Document 3 discloses a packaging form in which a disinfectant solution and a cotton swab in an amount necessary for one disinfection operation are stored in a bag-like sealed body.
Japanese Unexamined Patent Publication No. 7-96949 JP 2002-225934 A Utility Model Registration No. 2557914

  However, as disclosed in Patent Documents 1 to 3, when opening from a notch or the like, these packaging bags have a problem that the advantages of the material are tear resistance when opened and are difficult to break. Another problem is that the welded sealant resists tearing and is difficult to tear. Therefore, it may take time to open the packaging bag. Moreover, it may be opened suddenly by applying a large force and the inclusions may be spilled.

  Then, the further device for improving the openability of a packaging bag is required. This requires improving the packaging material to improve tear resistance.

  An object of the present invention is to provide an easily tearable packaging material that can be easily torn by improving tear resistance. Another object of the present invention is to provide an easy-open packaging bag using the easy-tearable packaging material.

In order to achieve the above object, the easily tearable packaging material of the present invention is a laminated packaging material having a heat-adhesive resin layer as the innermost layer.
Concavities and convexities comprising a plurality of concave portions and a plurality of convex portions are formed on the surface of the thermal adhesive resin layer, and the thickness of the thermal adhesive resin layer in the concave portions is the thickness of the thermal adhesive resin layer in the convex portions. 60% or less.

  According to this configuration, the easily tearable packaging material is torn along the recesses of the heat-adhesive resin layer.

  In order to obtain sufficient sealing strength in the easy tearing packaging material, it is preferable that the thickness of the heat-adhesive resin layer in the convex portion is 10 μm or more. Moreover, it is preferable from the viewpoint of suppressing the material cost of the thermoadhesive resin layer that the thickness of the thermoadhesive resin layer in the convex portion is 50 μm or less. Therefore, the thickness of the heat adhesive resin layer is preferably 10 μm or more and 50 μm or less.

  Further, in the above easy tearing packaging material, if the unevenness is formed at least in a portion to be opened, the unsealing property is secured.

  In the above easy tearing packaging material, the concave and convex portions can adopt a lattice shape in which concave portions intersect. According to this configuration, the packaging material is easily torn along the recess.

  In the above easy tear packaging material, the packaging material preferably has an aluminum layer. According to this configuration, the aluminum layer becomes a barrier layer, and the gas barrier property is improved.

  The easy-open packaging bag of the present invention is a bag made from the above easy-tear packaging material.

  According to the present invention, since the packaging material is torn along the concave portion of the heat-adhesive resin layer, that is, the thin portion of the heat-adhesive resin layer, an easily tearable packaging material with low tear resistance can be obtained. it can. Moreover, if this easily tearable packaging material is used, an easily openable packaging bag can be obtained.

  1 is a schematic cross-sectional view of the packaging material of the present invention, and FIG. 2 is a schematic plan view of the inner surface side of the packaging material of FIG. The packaging material 10 has a laminated structure, and a base material layer 11, a barrier layer 12, and a sealant layer (thermal adhesive resin layer) 13 are laminated in order from the outer layer to the inner layer.

  As the base material layer 11, various synthetic resin films such as polyethylene (PE), polypropylene, polyethylene terephthalate (PET), and nylon can be used as a single layer or laminated. Printing (not shown) and anchors (not shown) are usually applied to the back surface of the base material layer 11. The barrier layer 12 is a layer for improving gas barrier properties, and a metal such as aluminum can be used. This metal can be vapor deposited on a metal foil or the substrate layer 11.

  The sealant layer 13 is a layer that is welded during bag making, and the sealant layers 13 are welded together by means such as thermocompression bonding or ultrasonic welding to form a sealed bag. The sealant layer 13 is not particularly limited as long as it is a resin having thermal adhesiveness, but a resin having extrusion suitability is preferably used because it can be easily laminated using a T-die extruder. Examples of the resin having extrudability include low density polyethylene, linear low density polyethylene, ethylene acrylic acid, ethylene methacrylic acid (EMAA), ethylene vinyl alcohol, and polypropylene. The sealant layer 13 may be a resin film. In this case, the sealant layer 13 can be bonded to the barrier layer 12 using an adhesive.

  On the surface of the sealant layer 13, irregularities including a plurality of concave portions 13 a and a plurality of convex portions 13 b are formed. As shown in FIG. 2, the unevenness has a lattice shape in which the recesses 13a intersect. When the sealant layer 13 is laminated by a T-die extruder, the irregularities can be formed by providing irregularities on the chill roll. Moreover, what is necessary is just to use the resin film in which the unevenness | corrugation was formed previously, when using a resin film as the sealant layer 13. FIG. Moreover, even when a chill roll without unevenness or a resin film without unevenness is used, it is embossed with a jacket roll having unevenness in the subsequent process, or a mold with unevenness is pressed after pressing a heated plate. Thus, irregularities can be formed on the surface of the sealant layer 13.

  In the present invention, the unevenness of the sealant layer 13 is provided in order to realize easy tearability of the packaging material 10. If the packaging material 10 has easy tearability, an easily openable bag is obtained when it is formed into a packaging bag to be described later. Here, in order to realize easy tearability, the relationship between the thickness of the concave portion 13a of the sealant layer 13 and the thickness of the convex portion 13b is important.

  Generally, the thinner the sealant layer, the smaller the tear resistance and the better the tearability. However, if the sealant layer becomes thin, when the sealant layers are sealed together, sufficient seal strength cannot be obtained, or the seal part may come off. When the sealant layer is formed by extrusion, if the amount of extrusion is small, the amount of heat is insufficient and sufficient laminate strength cannot be obtained. Further, when an additive such as a slip agent is contained, the amount of the additive is reduced, and the effect of the additive may not be obtained. Further, if the total thickness of the packaging material is reduced by making the sealant layer thin, the waist is weak, so that wrinkles are easily formed, the design and texture are deteriorated, and filling suitability of the inclusions may not be obtained.

  As a result of consideration based on these, when the thickness of the convex portion 13b is less than 10 μm, the amount of the resin of the sealant layer 13 is too small, and there is a problem that sufficient seal strength cannot be obtained as described above. On the other hand, when the thickness of the convex portion 13b exceeds 50 μm, the amount of resin in the sealant layer 13 increases, which increases the cost, which is not realistic. Moreover, when the thickness of the recessed part 13a exceeds 60% of the thickness of the convex part 13b, since the difference of the thickness of the recessed part 13a and the convex part 13b is small, the effect which forms an unevenness | corrugation is hardly acquired.

  Accordingly, in the sealant layer 13, the thickness of the convex portion 13b is preferably 10 to 50 μm, and the thickness of the concave portion 13a is preferably 60% or less of the thickness of the convex portion 13b. More preferably, the thickness of the concave portion 13a is 50% or less of the thickness of the convex portion 13b.

  The packaging material 10 in which the sealant layer 13 in the above range is laminated has low tear resistance of the sealant layer 13 and is excellent in tearability. Furthermore, it has sufficient sealing strength when sealing the sealants together. This is probably because the packaging material 10 is easily torn along the recess 13a, so that the same easy tearability as when a thin sealant layer was employed was obtained. On the other hand, since the seal strength is determined by the resin amount of the sealant layer 13, it is considered that sufficient seal strength was obtained by maintaining the resin amount by sufficiently thickening the convex portion 13b. In addition to these, if the difference in unevenness of the sealant layer 13 is large, the slipperiness of the uneven surface is stabilized, so that post-processing suitability such as bag making is excellent.

  Examples of the packaging material 10 include a packaging material for a chemical-impregnated cotton packaging bag containing absorbent cotton impregnated with alcohol for disinfection, and the structure thereof is 12 μm as a base material layer 11 as shown in FIG. A thick PET 11a is laminated outside, a 15 μm thick PE 11b is laminated inside, a 7 μm thick aluminum foil is used as the barrier layer 12, and EMAA is laminated as a sealant layer 13 by a T-die extruder. In addition, the thickness of the recessed part 13a of the sealant layer 13 is 10 micrometers, and the thickness of the convex part 13b is 25 micrometers.

  In order to examine the tearability of this example, tear resistance was measured in accordance with Japanese Industrial Standard (JIS) P8116. As a comparative example to be compared with the example, a sample was used in which the thickness of the concave portion of the sealant layer was 23 μm, the thickness of the convex portion was 25 μm, and the other layer configuration was the same as in the example. For the measurement of tear resistance, an Elemendorf tester was used, and 16 samples were stacked and measured. Samples were prepared as normal and those immersed in ethanol for 30 minutes, and the flow direction and width direction of each sample were measured. A sample collected along the direction of travel in the extrusion process of laminating the sealant layer is called a sample in the flow direction, and a sample taken along the direction perpendicular to the flow direction is called a sample in the width direction. Table 1 shows the measurement results.

  As can be seen from Table 1, there is almost no difference between the flow direction and the width direction in the examples and comparative examples. And it turns out that an Example has a tear resistance smaller than a comparative example both after a normal state and ethanol immersion. In both the examples and comparative examples, the tear resistance is greater after immersion in ethanol than in the normal state, but is significantly greater in the comparative examples.

  In this example, since the inclusion is absorbent cotton impregnated with alcohol for disinfection, it is preferable to evaluate the measurement results after ethanol immersion in Table 1 in preference to normal conditions because it is in line with actual use. After immersion in ethanol, the tear resistance of the example is much lower than the tear resistance of the comparative example, and easy tearability is realized in the example. In the normal state, the tear resistance of the example is lower than that of the comparative example. From these results, it can be said that when the difference in the unevenness of the sealant layer 13 is increased, easy tearability can be obtained.

  In addition to the above embodiments, several configurations are illustrated. For example, when used as a packaging material for powdered beverages, 12 μm thick PET is laminated on the outside as the base material layer 11, 15 μm thick PE is laminated on the inside, 7 μm thick aluminum foil is used as the barrier layer 12, and the sealant layer 13 As a laminate, PE laminated with a T-die extruder can be used. In addition, the thickness of the recessed part 13a of the sealant layer 13 is 15 micrometers, and the thickness of the convex part 13b is 35 micrometers.

  In addition, for example, when used as a packaging material for kaya or powder soup for instant food, 20 μm-thick uniaxially stretched polypropylene, 12 μm-thick PET, and 15 μm-thick PE are laminated in order from the outside as the base layer 11 to form the barrier layer 12. A 7 μm thick aluminum foil and PE laminated with a T-die extruder can be used as the sealant layer 13. In addition, the thickness of the recessed part 13a of the sealant layer 13 is 8 micrometers, and the thickness of the convex part 13b is 20 micrometers.

  Also, for example, when used as a packaging material for instant food liquid soup, 15 μm thick stretched nylon is used as a base material layer 11 having a barrier layer function, and PE is laminated as a sealant layer 13 by a T-die extruder. Can be used. In addition, the thickness of the recessed part 13a of the sealant layer 13 is 30 micrometers, and the thickness of the convex part 13b is 50 micrometers.

  Next, the case where the sealant layer 13 having unevenness is laminated using a T-die extruder will be described in detail. FIG. 3 is a schematic diagram of a main part of a T-die extruder. In the figure, 10 'is a film in which a base material layer 11 and a barrier layer 12 are laminated, 13' is a heat-adhesive resin that becomes a sealant layer 13, 20 is a chill roll, 21 is a rubber roll, and 22 is an extrusion part of a T-die extruder. It is.

  As shown in FIG. 3, the film 10 ′ is supplied between the rolls nipped by the chill roll 20 and the rubber roll 21, and the molten thermoadhesive resin 13 ′ supplied from the extrusion unit 22 is laminated to produce the packaging material 10. Is done. At this time, since the heat-adhesive resin 13 ′ is supplied to the chill roll side, it is molded along the surface shape of the chill roll, and is cooled and solidified.

  4 is a front view of the chill roll, and FIG. 5 is an enlarged view of the chill roll surface of FIG. This chill roll 20 forms the grid-shaped irregularities shown in FIGS. 1 and 2. As shown in FIG. 5, the surface of the chill roll 20 has a lattice shape including a concave portion 20 a of a regular quadrangular pyramid and a protruding portion 20 b that intersects. For example, when producing the packaging material 10 of the above-described embodiment, the length L of one side of the recess 20a is 200 μm, and the plate depth is 70 μm.

  Next, bag making of the packaging material 10 will be described. The produced packaging material 10 is made using a known automatic bag making and filling device and the like, and is filled with inclusions, and a packaging bag 30 as shown in FIG. 6 is produced. The packaging bag 30 of FIG. 6 is a three-side seal type sealing bag in which the sealant layers 13 are welded to each other, and an opening notch 32 is formed at the end of the seal portion 31.

  When the packaging bag 30 is opened from the notch 32, the sealing portion 31 is first torn, and then the portion of the packaging material 10 alone that is not sealed is torn straight. When the packaging material 10 itself is torn, it is torn along the recess 13a of the sealant layer 13, so that the tear resistance of the sealant layer 13 is small and can be opened quickly.

  In addition, in the packaging bag 30, the unevenness | corrugation of the sealant layer 13 should just be formed in the opening planned part at least. The portion to be opened is a portion where the packaging material 10 will be torn when it is opened from the notch 32, and may be a region having a slight width above and below the notch 32. For example, it can be set as the area | region 33 enclosed with the broken line of FIG.

  The shape of the packaging bag is not particularly limited, and other than the above three-side seal type, a pillow type or a four-side seal type may be used. Moreover, there is no limitation in the means for opening, and means other than said notch 32 may be employ | adopted.

  In the above embodiment, the unevenness of the sealant layer 13 has been described by taking the lattice shape as an example, but the shape is not limited to this shape. For example, it is good also as an uneven | corrugated shape as shown in FIG. In FIG. 7, it is an uneven | corrugated shape which consists of the convex-shaped recessed part 13c and the other convex part 13d. Thereby, at the time of tearing of the packaging material 10, it is torn so that it may transmit between the recessed parts 13c like the arrow in a figure. Therefore, an easily tearable packaging material is obtained as in the above embodiment, and a packaging bag using the packaging material also has an easy opening property.

  By making a bag, the packaging material of the present invention can be effectively used as a packaging bag for subdividing products of various types and shapes such as foods, medicines, small items, liquids, powders, pastes, solids, and the like.

It is a schematic cross section of the packaging material of the present invention. It is a plane schematic diagram by the side of the inner surface of the packaging material of FIG. It is a principal part schematic diagram of a T-die extruder. It is a front view of the chill roll of the present invention. It is an enlarged view of the chill roll surface of FIG. It is a plane schematic diagram of the packaging bag of this invention. It is a plane schematic diagram by the inner surface side of the packaging material of the other form of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Packaging material 13 Thermal adhesive resin layer 13a, 13c Concave part 13b, 13d Convex part 30 Packaging bag

Claims (5)

In a packaging material with a laminated structure having a heat-adhesive resin layer as the innermost layer,
The surface of the thermoadhesive resin layer is formed with irregularities comprising a plurality of C-shaped concave portions and other convex portions, and the thickness of the thermal adhesive resin layer in the concave portions is the thermal bonding in the convex portions. An easily tearable packaging material characterized by being 60% or less of the thickness of the conductive resin layer.   The easily tearable packaging material according to claim 1, wherein a thickness of the heat-adhesive resin layer in the convex portion is 10 μm or more and 50 μm or less.   The easily tearable packaging material according to claim 1 or 2, wherein the unevenness is formed at least in a portion to be opened. The easily tearable packaging material according to any one of claims 1 to 3, wherein the packaging material has an aluminum layer. An easily openable packaging bag made from the easily tearable packaging material according to any one of claims 1 to 4.

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