JP2023125717A - Laminate film for packaging bag, packaging bag, package for transportation, and method for manufacturing laminate film for packaging bag - Google Patents

Abstract

To provide a laminate film for a packaging bag which can suppress generation of pin holes in the laminate film for the packaging bag, a packaging bag, a package for transportation, and a method for manufacturing the laminate film for the packaging bag.SOLUTION: There is provided a laminate film for a packaging bag in which a protective layer formed of a material having a melting heat quantity of 100 mJ/mg or less at 110-175°C, a base material layer and a sealant layer are stacked in this order. The protective layer is preferably arranged on an outermost surface of the laminate film for the packaging bag. Visible light transmittance in a thickness direction of the laminate film for the packaging bag is preferably 50% or more.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a laminate film for packaging bags, a packaging bag, a package for transportation, and a method for manufacturing a laminate film for packaging bags.

According to Patent Document 1, packaging bags generally have a technical problem in that pinholes tend to occur during the distribution process, especially when the contents are fluid, are for low-temperature storage, or have a large capacity. It had This document discloses a pinhole-resistant laminated film for packaging bags, which is characterized in that the inner layer of a stretched nylon film is provided with a heat-adhesive layer, and the outer layer is laminated with a protective layer made of a polyolefin film. The company says that by adopting it for bags, it will be able to solve the above technical issues.

Note that Patent Document 2 describes a method for producing polypropylene resin for industrial use such as automobile parts, and in particular, as one method for confirming the mechanical strength of polypropylene resin, the heat of fusion of the produced resin is measured. .

Japanese Patent Application Publication No. 8-323937 Japanese Patent Application Publication No. 8-81594

Traditionally, packaging bags have been subject to various loads such as twisting, impact, and friction during bag making and filling, transportation, etc., which has caused pinholes to form in the packaging bag laminate film that makes up the packaging bag. There was a problem that sometimes

If pinholes or the like occur in the laminate film for packaging bags, it will lead to loss of contents. Furthermore, if pinholes or other damage occurs in the laminate film for packaging bags during transportation, it may be necessary to discard the entire product being transported.

On the other hand, Patent Document 1 discloses laminating a protective layer made of a polyolefin film on the outer layer in order to suppress the occurrence of such pinholes.

However, there is a need to further suppress the occurrence of pinholes in the laminate film for packaging bags.

That is, the present invention provides a laminate film for packaging bags, a packaging bag, a package for transportation, and such a laminate film for packaging bags, which can suppress the occurrence of pinholes in the laminate film for packaging bags. The purpose is to provide a manufacturing method for.

The present inventor has discovered that the above object can be achieved by the following means:
《Aspect 1》
A laminate film for packaging bags, comprising a protective layer, a base layer, and a sealant layer made of a material having a heat of fusion of 100 mJ/mg or less at 110° C. to 175° C., which are laminated in this order.
《Aspect 2》
The laminate film for a packaging bag according to aspect 1, wherein the protective layer is disposed on the outermost surface.
《Aspect 3》
The laminate film for packaging bags according to aspect 1 or 2, having a visible light transmittance in the thickness direction of 50% or more.
《Aspect 4》
The laminate film for packaging bags according to any one of aspects 1 to 3, wherein the protective layer has a thickness of 10 μm to 40 μm.
《Aspect 5》
The laminate film for packaging bags according to any one of aspects 1 to 4, wherein the material having a heat of fusion of 100 mJ/mg or less at 110° C. to 175° C. contains polypropylene.
《Aspect 6》
A packaging bag, at least a portion of which is composed of the laminate film for packaging bags according to any one of aspects 1 to 5.
《Aspect 7》
The packaging bag according to aspect 6, which is pillow-shaped.
《Aspect 8》
The packaging bag according to aspect 6 or 7, wherein the length in the longitudinal direction is 300 mm or more and the length in the width direction is 150 mm or more.
《Aspect 9》
The packaging bag according to any one of aspects 6 to 8, wherein the inside is filled with contents.
《Aspect 10》
The packaging bag according to aspect 9, wherein the contents contain a liquid.
《Aspect 11》
The packaging bag according to aspect 9 or 10, wherein the weight of the contents is 1 kg or more.
《Aspect 12》
A transportation package, in which the packaging bags according to any one of aspects 9 to 11 are stacked on top of each other and packed in cardboard.
《Aspect 13》
A method for producing a laminate film for packaging bags according to any one of aspects 1 to 5, comprising:
Heat-treating and modifying a protective layer precursor having a heat of fusion of more than 100 mJ/mg at 110° C. to 175° C. to obtain a protective layer having a heat of fusion of 100 mJ/mg or less at 110° C. to 175° C.;
A method for producing a laminate film for packaging bags, comprising:

According to the present invention, a laminate film for packaging bags, a packaging bag, a package for transportation, and such a laminate film for packaging bags can suppress the occurrence of pinholes in the laminate film for packaging bags. A manufacturing method can be provided.

FIG. 1 is a schematic diagram of a laminate film 1 for packaging bags according to a first embodiment of the present invention. FIG. 2 is a schematic diagram of the packaging bag 2 according to the first embodiment of the present invention. FIG. 3 is a sectional view taken along line A-A' in FIG. FIG. 4 is a schematic diagram of the transport package 3 according to the first embodiment of the present invention.

Embodiments of the present invention will be described in detail below. Note that the present invention is not limited to the following embodiments, but can be implemented with various modifications within the scope of the gist of the disclosure.

《Laminated film for packaging bags》
The laminate film for packaging bags of the present invention includes a protective layer made of a material having a heat of fusion of 100 mJ/mg or less at 110° C. to 175° C., a base material layer, and a sealant layer, which are laminated in this order.

The laminate film for packaging bags of the present invention has a protective layer made of a material having a heat of fusion of 100 mJ/mg or less at 110°C to 175°C. The occurrence of pinholes during manufacturing, transportation, storage, etc. can be suppressed.

The occurrence of pinholes in the laminate film for packaging bags is caused by, for example, but not limited to, friction between the laminate film for packaging bags and the manufacturing machine during the manufacturing of packaging bags, transportation, storage, and display. This can occur due to various mechanical effects, such as impact and friction caused by collisions between packaging bags and the cardboard boxes used to pack packaging bags.

A protective layer made of a material with a heat of fusion of 100 mJ/mg or less at 110°C to 175°C has significantly low crystallinity and is therefore soft and prone to pinholes caused by various mechanical effects, including but not limited to these. is less likely to occur.

Therefore, packaging bags using the laminate film for packaging bags of the present invention, which has a protective layer made of a material with a heat of fusion of 100 mJ/mg or less at 110°C to 175°C, cannot be destroyed due to pinholes, etc. is less likely to occur.

FIG. 1 is a schematic diagram of a laminate film 1 for packaging bags according to a first embodiment of the present invention. Moreover, FIG. 2 is a schematic diagram of the packaging bag 2 according to the first embodiment of the present invention. Note that FIGS. 1 and 2 are not intended to limit the present invention.

As shown in FIG. 1, the laminate film 1 for packaging bags according to the first embodiment of the present invention includes a protective layer 11 made of a material having a heat of fusion of 100 mJ/mg or less at 110° C. to 175° C., and a base material layer. 12 and sealant layer 13 are laminated in this order. Further, the protective layer 11 and the base material layer 12 are bonded to each other by an adhesive layer 14a. Similarly, the base material layer 12 and the sealant layer 13 are bonded to each other by an adhesive layer 14b.

For example, by bonding one or more laminate films 1 for packaging bags according to the first embodiment of the present invention and their sealant layers 13 together by heat fusion to form a bag shape, as shown in FIG. A packaging bag 2 like this can be formed.

In such a packaging bag 2, the protective layer 11 forms the outermost surface of the packaging bag 2, and the sealant layer 13 forms the innermost surface of the packaging bag 2. Since the protective layer 11 forms the outermost surface of the packaging bag 2, the packaging bag 2 is easily protected from various mechanical effects such as impact and friction.

In addition, since the laminate film for packaging bags of the present invention can suppress the occurrence of pinholes, etc., it is particularly preferable to apply it to packaging bags for transportation.

Packaging bags for transportation may be required to have high visibility so that the contents can be checked from the outside. Therefore, it is particularly preferable that the laminate film for packaging bags of the present invention has a visible light transmittance of 50% or more in the thickness direction.

The visible light transmittance in the thickness direction may be 50% or more and less than 100%. The visible light transmittance in the thickness direction may be 50% or more, 60% or more, 70% or more, or 80% or more, and less than 100%, 95% or less, 90% or less, or 85% or less. good.

Note that the visible light transmittance in the thickness direction can be measured in accordance with JIS K 7361.

<Protective layer>
The protective layer of the laminate film for packaging bags of the present invention is made of a material having a heat of fusion of 100 mJ/mg or less at 110°C to 175°C.

A material having such a heat of fusion has low crystallinity and is flexible, so pinholes are less likely to occur due to friction or impact.

From the viewpoint of protecting the other layers of the laminate film for packaging bags, the protective layer is particularly preferably disposed on the outermost surface of the laminate film for packaging bags.

Further, the thickness of the protective layer is preferably 10 μm to 40 μm. When the thickness of the protective layer is 10 μm or more, the strength of the protective layer is high, and pinholes are less likely to occur due to friction or impact. On the other hand, when the thickness of the protective layer is 40 μm or less, the flexibility of the laminate film for packaging bags can be increased. Since the packaging bag is deformed by being filled with contents, it is advantageous that the packaging bag laminate film constituting the packaging bag has a suitably high flexibility.

The thickness of the protective layer may be 10 μm or more, 15 μm or more, 20 μm or more, or 25 μm or more, and may be 40 μm or less, 35 μm or less, 30 μm or less, or 25 μm or less.

The material constituting the protective layer is not particularly limited as long as it has a heat of fusion of 100 mJ/mg or less at 110° C. to 175° C. Such a material may be, for example, an organic resin, specifically a thermoplastic resin, more specifically a polyolefin, provided that the heat of fusion is 100 mJ/mg or less.

From the viewpoint of bending resistance, it is particularly preferable that the material constituting the protective layer contains polypropylene having a heat of fusion of 100 mJ/mg or less at 110° C. to 175° C. The protective layer is preferably a layer made of polypropylene having a heat of fusion of 100 mJ/mg or less at 110° C. to 175° C. The protective layer may further contain components other than polypropylene.

The material having a heat of fusion of 100 mJ/mg or less at 110° C. to 175° C. may be, for example, a commercially available polypropylene sheet having such a heat of fusion. Note that commercially available polypropylene sheets may further contain components other than polypropylene. In addition, a material having a heat of fusion of 100 mJ/mg or less at 110°C to 175°C, for example a polypropylene sheet having such a heat of fusion, is a material that does not have such a heat of fusion, for example a material that does not have such a heat of fusion. It can be obtained by subjecting a polypropylene sheet to the heat treatment described in the following <<Method for producing laminate film for packaging bags>>.

In addition, the heat of fusion can be measured by input compensation DSC as the heat of fusion (transition heat) of a sample adjusted in a standard state, in accordance with JIS K 7122:1987 ("Method for measuring heat of transition of plastics"). .

<Base material layer>
Examples of the base material layer include polyolefins such as polyethylene (PE), polyesters such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polyamides such as 6-nylon and 6,6-nylon, and polystyrene (PS). , or vinyl chloride (PVC).

The base layer may be constructed using a stretched material. This stretching may be uniaxial or biaxial stretching.

The thickness of the base material layer is not particularly limited, but in order to provide sufficient strength to the resulting packaging bag, it can be, for example, 7 μm or more, preferably 10 μm or more. Further, when it is assumed that the packaging bag is to be opened by tearing it open, the thickness can be set to 50 μm or less, and preferably 30 μm or less, in order to provide cuttability.

The thickness of the base layer may be 7 μm or more, 10 μm or more, 20 μm or more, or 25 μm or more, and may be 50 μm or less, 40 μm or less, 35 μm or less, or 30 μm or less.

<Sealant layer>
The sealant layer may be, for example, a thermoplastic resin such as low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), polypropylene (PP), ethylene-acetic acid. Vinyl copolymers, ionomer resins, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid alkyl ester copolymers, ethylene-propylene copolymers (EPM), polymethylpentene, polybutene, etc. Materials can be listed.

The thickness of the sealant layer can be, for example, 20 μm or more or 30 μm or more, and can be, for example, 80 μm or less or 70 μm or less.

<Other layers>
The laminate film for packaging bags of the present invention may optionally have other layers in addition to the above layers. Examples of other layers include, but are not limited to, adhesive layers and barrier layers.

The adhesive layer is disposed between layers constituting a laminate film for packaging bags, for example, a protective layer and a base layer, and/or a base layer and a sealant layer in order to adhere them to each other. It can be a layer of adhesive.

As the adhesive used for the adhesive layer, those commonly used for manufacturing packaging bags can be used.

The barrier layer is a layer that has the function of suppressing the entry of gas (particularly oxygen), moisture, and/or light from the outside world and protecting the contents.

Examples of the barrier layer include layers of aluminum, alumina, silica, polyvinylidene chloride, and polyvinyl alcohol. Note that when an aluminum layer is used as a barrier layer, there is a possibility that the visibility from the outside to the inside of the packaging bag will be impaired, but the laminate film for packaging bags is suitable for packaging bags where visibility is not required. It is also possible to apply to

The barrier layer may be used as an independent film or foil in the production of the laminate film for packaging bags used in the present invention, or it may be preformed in a layered state on one or both sides of a suitable base layer. The supplied laminated material may be used as is.

The thickness of the barrier layer may be, for example, 1 μm or more, 3 μm or more, or 5 μm or more, and 10 μm or less, or 8 μm or less when the barrier layer is provided as a separate film or foil. . When the barrier layer is provided as a layer formed on a base material layer, the thickness may be, for example, 1 nm or more, 3 nm or more, or 5 nm or more, and 500 nm or less, 300 nm or less, or 200 nm or less.

《Packaging bag》
The packaging bag of the present invention is composed of the laminate film for packaging bags of the present invention.

Since the packaging bag of the present invention is constituted by the laminate film for packaging bags of the present invention, the occurrence of pinholes etc. due to various mechanical effects such as impact and friction is suppressed.

FIG. 2 is a schematic diagram of the packaging bag 2 according to the first embodiment of the present invention. Further, FIG. 3 is a sectional view taken along line A-A' in FIG. Note that FIGS. 2 and 3 are not intended to limit the present invention.

As shown in FIGS. 2 and 3, the packaging bag 2 according to the first embodiment of the present invention has a structure in which two laminate films 1 for packaging bags according to the first embodiment of the present invention are bonded together. There is. In the packaging bag 2, the sealant layers 13 of the laminate film 1 for packaging bags are heat-sealed to each other at the edge 21 to form a bag shape. The storage portion 22 of the packaging bag 2 stores the contents. Note that in FIG. 3, the adhesive layers 14a and 14b are omitted for simplification.

The packaging bag of the present invention is particularly suitable as a packaging bag for transportation from the viewpoint that the occurrence of pinholes and the like due to various mechanical effects such as impact and friction is suppressed.

<Shape, dimensions, etc.>
The shape of the packaging bag of the present invention is not particularly limited as long as it can accommodate the contents, and may be, for example, a three-sided bag, a four-sided bag, or a pillow-shaped bag.

When the packaging bag of the present invention is a packaging bag for transportation, for example, it is assumed that the packaging bag is filled with contents and transported by being arranged in a cardboard box or a container so as to be stacked on top of each other. . In this case, from the viewpoint of suppressing the occurrence of pinholes and the like due to the packaging bags coming into contact with each other and rubbing, it is preferable that the portion where the packaging bags overlap each other is a flat surface of the packaging bag, that is, a portion other than the end portions. From this point of view, it is particularly preferable that the packaging bag of the present invention has a pillow shape.

The dimensions of the packaging bag of the present invention are not particularly limited, but for example, in the case of a three-sided bag, a four-sided bag, or a pillow shape, the length in the longitudinal direction may be 300 mm or more and the length in the width direction may be 150 mm or more. .

The length of the packaging bag of the present invention in the longitudinal direction may be 300 mm or more, 400 mm or more, 500 mm or more, or 600 mm or more. Moreover, the length in the longitudinal direction may be 1000 mm or less, 900 mm or less, or 800 mm or less.

<Contents>
In the packaging bag of the present invention, the inside thereof, that is, the accommodating portion thereof, can be filled with contents.

The contents are not particularly limited, and may be, for example, a fluid, a powder, a granule, or a combination thereof. The fluid may be a gas, liquid, sol, gel, or slurry.

The contents may be water, food, or other materials. The water may be, for example, drinking water. The food may be, for example, a soft drink such as juice or tea; a seasoning such as sugar, salt, pepper, soy sauce, sauce, or dressing; a retort food such as retort curry; cereal, flour, or bread crumbs. Other materials may include, for example, chemicals such as soap solutions, shampoo solutions, or detergents; feed for livestock; construction materials such as gravel, sand, or lime; or agricultural materials such as agricultural chemicals or compost. However, there is no particular limitation.

However, the packaging bag of the present invention is particularly useful when the bag contains a fluid, particularly a liquid, which is particularly susceptible to spillage of the contents and contamination of the surrounding area due to the occurrence of pinholes.

The content filled in the packaging bag of the present invention may be 1 kg or more and 100 kg or less, depending on the size of the packaging bag and the strength of the laminate film for packaging bags constituting the packaging bag.

The content filled in the packaging bag of the present invention may be 1 kg or more, 2 kg or more, 5 kg or more, or 10 kg or more, and may be 100 kg or less, 50 kg or less, 40 kg or less, or 20 kg or less.

Packaging bags filled with contents of 1 kg or more are heavy, so they are subject to various mechanical effects such as impact and friction due to collisions between the packaging bags and the cardboard etc. in which the packaging bags are packed. The packaging bag is prone to pinholes, etc. Therefore, the packaging bag of the present invention is particularly effectively applied to packaging bags filled with such heavy contents.

《Transportation packaging》
In the transport package of the present invention, the packaging bags of the present invention filled with contents are stacked on top of each other and packed in corrugated cardboard.

The transport package of the present invention is packed with the packaging bag of the present invention containing contents. Therefore, during transportation, the packaging bags are less likely to be destroyed by various mechanical effects such as impact and friction due to collisions between the packaging bags and the cardboard boxes in which the packaging bags are packed. Therefore, the contents can be safely transported.

FIG. 4 is a schematic diagram of the transport package 3 according to the first embodiment of the present invention. Note that FIG. 4 is not intended to limit the present invention.

As shown in FIG. 4, the transport package 3 according to the first embodiment of the present invention includes two packaging bags 2' each containing contents stacked on top of each other and packed in a cardboard box 31. Note that FIG. 4 is shown as a cross-sectional view of the transport package 3 having a rectangular parallelepiped shape.

In general, in the transportation package 3 as shown in FIG. 4, parts of the packaging bags 2' containing the contents are in contact with each other due to the start, stop, deceleration, acceleration, etc. of the transportation vehicle during transportation. In the area where the packaging bag 2' containing the contents is in contact with the cardboard 31, the surface of the packaging bag 2' containing the contents is susceptible to various mechanical effects such as impact and friction.

The transport package 3 according to the first embodiment of the present invention employs a packaging bag 2' containing contents, which is unlikely to be destroyed by various mechanical actions such as these, so that the contents are can be transported safely.

《Method for manufacturing laminate film for packaging bags》
The laminate film for packaging bags of the present invention can, for example, combine the protective layer, base material layer, sealant layer, and optional other layers in the above-mentioned <<laminate film for packaging bags>> with at least the protective layer, the base material layer, and a sealant layer can be formed by laminating them in this order.

The layers can be bonded together by a known method, such as by bonding the layers together using an adhesive layer using a dry lamination method, for example.

Even if the material sheet used for the protective layer, that is, the protective layer precursor, has a heat of fusion of more than 100 mJ/mg at 110°C to 175°C, the protective layer precursor may be heat-treated, thereby reducing the temperature at 110°C to 175°C. A protective layer precursor having a heat of fusion of more than 100 mJ/mg at 110° C. to 175° C. can be modified into a protective layer having a heat of fusion of 100 mJ/mg or less at 110° C. to 175° C.

Therefore, the laminate film for packaging bags of the present invention can be obtained by heat-treating a material sheet having a heat of fusion of more than 100 mJ/mg at 110° C. to 175° C., that is, a protective layer precursor, and thereby having a heat of fusion of more than 100 mJ/mg. A protective layer precursor is modified to form a protective layer having a heat of fusion of 100 mJ/mg or less, and then a protective layer, a base material layer, and optionally a sealant layer are laminated in this order to produce a laminated layer for packaging bags. can form a body film.

In addition, heat treatment for the protective layer precursor is performed by first laminating the protective layer precursor, base material layer, and optional sealant layer in this order to form a laminate film precursor for packaging bags, and then The laminate film precursor may be heat treated to form a laminate film for packaging bags.

For example, when the protective layer precursor is a material with a heat of fusion of more than 100 mJ/mg at 110°C to 175°C, the heat treatment is performed at a temperature of 50°C to 100°C for 12 to 120 hours. This can be done by heating.

The heating temperature in the heat treatment may be 50°C or higher, 55°C or higher, 60°C or higher, or 65°C or higher, and may be 100°C or lower, 95°C or lower, 90°C or lower, or 85°C or lower.

The heat treatment time may be 12 hours or more, 15 hours or more, 18 hours or more, or 24 hours or more, and may be 120 hours or less, 100 hours or less, 80 hours or less, or 60 hours or less.

《Examples 1 to 4 and Comparative Example 1》
<Comparative example 1>
A polypropylene sheet A (thickness 20 μm) with a heat of fusion of 103.5 mJ/mg at 110° C. to 175° C. as a protective layer, a nylon sheet (thickness 15 μm) as a base layer, and a low-density polyethylene film (as a sealant layer) A laminate film for packaging bags of Comparative Example 1 was prepared by dry laminating the films (with a thickness of 70 μm) using a dry laminating adhesive in this order and aging them at 40°C for 96 hours. .

Using the laminate film for packaging bags of Comparative Example 1, a pillow-shaped packaging bag with a length of 380 mm and a width of 200 mm was produced, and the packaging bag of Comparative Example 1 was obtained. Specifically, the laminate film for a packaging bag was sealed by heat fusion so that the sealant layers faced each other to form a cylinder. Next, a seal was applied in a direction perpendicular to the sealed portion of the cylindrical molded body.

The inside of the packaging bag of Comparative Example 1, that is, the storage part, was filled with 2 kg of water and sealed to obtain a packaging bag filled with the contents of Comparative Example 1.

Note that the static friction coefficient of polypropylene sheet A was 0.13.

Table 1 shows the configuration of the packaging bag.

<Example 1>
Polypropylene sheet A (thickness 20 μm), which was used as the protective layer in Comparative Example 1 and had a heat of fusion of 103.5 mJ/mg at 110°C to 175°C, was heat-treated at 80°C for 24 hours to determine the heat of fusion of the polypropylene sheet. After lowering the nylon sheet (thickness: 15 μm) as a base material layer and a low-density polyethylene film (thickness: 70 μm) as a sealant layer in this order in the same manner as in Example 1, dry lamination was prepared. They were bonded together by a dry lamination method using an adhesive and aged for 96 hours at 40° C. to obtain a laminate film for packaging bags. The heat of fusion of the heat-treated polypropylene sheet A' at 110°C to 175°C was determined to be 92.8 mJ/mg by a method based on JIS K 7122:1987 ("Method for measuring heat of transition of plastics"). Met. A packaging bag filled with the contents of Example 1 was produced in the same manner as Comparative Example 1 except that the above heat treatment was performed.

Note that the static friction coefficient of the polypropylene sheet A' was 0.12.

Table 1 shows the configuration of the packaging bag.

<Example 2>
The contents of Example 2 were filled in the same manner as Comparative Example 1 except that polypropylene sheet B (thickness 20 μm) having a heat of fusion of 84.0 mJ/mg at 110° C. to 175° C. was used as the protective layer. A packaging bag was produced.

Note that the static friction coefficient of polypropylene sheet B was 0.17.

Table 1 shows the configuration of the packaging bag.

<Example 3>
The contents of Example 2 were filled in the same manner as Comparative Example 1 except that polypropylene sheet C (thickness 25 μm) having a heat of fusion of 84.7 mJ/mg at 110° C. to 175° C. was used as the protective layer. A packaging bag was produced.

Note that the static friction coefficient of polypropylene sheet C was 0.21.

Table 1 shows the configuration of the packaging bag.

<Example 4>
The contents of Example 2 were filled in the same manner as Comparative Example 1 except that polypropylene sheet D (thickness 20 μm) having a heat of fusion of 99.2 mJ/mg at 110° C. to 175° C. was used as the protective layer. A packaging bag was produced.

Note that the static friction coefficient of polypropylene sheet D was 0.26.

Table 1 shows the configuration of the packaging bag.

<Vibration test>
Two packaging bags of each example filled with the contents were stacked on top of each other in a cardboard box with a depth of 293 mm, a width of 176 mm, and a height of 118 mm, and the bags were packed to obtain a transportation package. More specifically, they were arranged and packed as shown in FIG. Three transport packages were prepared for each.

The transport package was stored at 5°C or lower for 24 hours or more, and a transport test was performed using a transport packaging machine BF-100UT manufactured by Idex (Test conditions: gravitational acceleration 3.5G, 5 minute sweep (10Hz to 40Hz) The test was carried out 4 times for a total of 20 minutes (equivalent to 1000 km).

As a result of the vibration test, those in which no liquid leakage occurred in any of the three transportation packages were rated as "acceptable," and those in which liquid leakage occurred in any of the three transportation packages were rated as "unacceptable."

The results are shown in Table 1.

<result>
Table 1 is a table showing the configuration of the packaging bag of each example and the results of the vibration test.

As shown in Table 1, the packaging bag of Comparative Example 1 in which the protective layer had a heat of fusion of 103.5 mJ/mg at 110° C. to 175° C. leaked in the vibration test. On the other hand, in Examples 1 to 3, the heat of fusion of the protective layer at 110°C to 175°C was 92.8 mJ/mg, 84.0 mJ/mg, 84.7 mJ/mg, and 99.2 mJ/mg, respectively. No liquid leakage occurred in any of the packaging bags No. 4 in the vibration test. This result shows that the packaging bags of Examples 1 to 4 have high resistance to the occurrence of pinholes.

Table 1 shows that although the static friction coefficients of the protective layers of Examples 1 to 4 are equal to or larger than the static friction coefficient of the protective layer of Comparative Example 1, that is, the static friction coefficients of the protective layers of Examples 1 to 4 are In the packaging bag, although the force generated by friction is equal to or greater than that of the packaging bag of Comparative Example 1, the packaging bags of Examples 1 to 4 have high resistance to the occurrence of pinholes. be understood.

1 Laminated film for packaging bags 11 Protective layer 12 Base material layer 13 Sealant layer 14a and b Adhesive layer 2 Packaging bag 2' Packaging bag with contents 21 Edge 22 Storage part 3 Transport packaging 31 Cardboard

Claims (13)

A laminate film for packaging bags, comprising a protective layer, a base layer, and a sealant layer made of a material having a heat of fusion of 100 mJ/mg or less at 110° C. to 175° C., which are laminated in this order. The laminate film for a packaging bag according to claim 1, wherein the protective layer is disposed on the outermost surface. The laminate film for packaging bags according to claim 1 or 2, wherein the visible light transmittance in the thickness direction is 50% or more. The laminate film for packaging bags according to any one of claims 1 to 3, wherein the protective layer has a thickness of 10 μm to 40 μm. The laminate film for packaging bags according to any one of claims 1 to 4, wherein the material having a heat of fusion of 100 mJ/mg or less at 110° C. to 175° C. contains polypropylene. A packaging bag, at least a part of which is composed of the laminate film for packaging bags according to any one of claims 1 to 5. The packaging bag according to claim 6, which is pillow-shaped. The packaging bag according to claim 6 or 7, wherein the length in the longitudinal direction is 300 mm or more and the length in the width direction is 150 mm or more. The packaging bag according to any one of claims 6 to 8, wherein the inside is filled with contents. The packaging bag according to claim 9, wherein the contents contain a liquid. The packaging bag according to claim 9 or 10, wherein the weight of the contents is 1 kg or more. A transport package comprising a plurality of packaging bags according to any one of claims 9 to 11 stacked on top of each other and packed in corrugated cardboard. A method for producing a laminate film for packaging bags according to any one of claims 1 to 5, comprising:
Heat-treating and modifying a protective layer precursor having a heat of fusion of more than 100 mJ/mg at 110° C. to 175° C. to obtain a protective layer having a heat of fusion of 100 mJ/mg or less at 110° C. to 175° C.;
A method for producing a laminate film for packaging bags, comprising:

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