JP7346945B2 - Laminate for packaging materials - Google Patents

Description

The present invention is for producing packaging bags used in the medical and pharmaceutical fields for storing soft bags filled with medicinal solutions such as infusions, and packaging materials for vacuum packaging and degassing packaging of electronic components and industrial products. The present invention relates to a laminate.

In recent years, efforts have been made to reduce the volume of packaging materials in response to environmental issues. The same is true in the field of flexible packaging, which mainly uses plastic films, but as a result of volume reduction and thinner layers, puncture strength tends to be insufficient, especially when the contents are heavy and solid. During transportation, depending on the shape of the contents, the packaging material may be pierced or pinholes may occur, impairing the shelf life of the contents, and there is a need for improvements in packaging materials.

Conventionally, packaging materials for pharmaceuticals such as infusion bags have been made from composite films made by sequentially laminating stretched polypropylene film, stretched nylon film, aluminum foil, and linear low-density polyethylene resin to provide pinhole resistance. It was configured.

However, packaging bags made of packaging materials using such composite films are expensive, and during the transportation process, packaging bags rub against each other and cardboard, and vibrations at bent parts and rubbing against protrusions of the contents occur. There has been a problem in that pinholes are likely to occur due to complex factors such as.

In addition, a structure consisting of a biaxially oriented polypropylene (OPP) layer/a barrier layer such as polyvinyl alcohol (PVA)/a linear low density polyethylene (L-LDPE) layer, or a structure consisting of a biaxially oriented nylon (ONy) layer/PVA etc. Barrier laminate materials having a barrier layer/low-density polyethylene (LDPE) structure have been widely used for packaging bags, but the prevention of pinholes has been insufficient.

In order to prevent the occurrence of pinholes in the outer packaging bag of an infusion bag package, a method of double-wrapping the outer packaging bag, as seen in food packaging, has also been adopted. However, the shape of the bag is simply double packaging with a three-sided seal bag, or a double bag packaging method in which two layers of film are stacked and the infusion bag is stored as a three-sided seal bag, and then the top opening of the outer packaging bag is sealed. However, at present, it is not possible to completely prevent pinholes from being generated on the film surface near the bottom seal portion of the outer packaging bag due to rocking on either or both of the outer layer side and the inner layer side.

In addition, methods have been proposed for storing and fixing the contents of the infusion bag depending on the size and shape of the outer packaging bag of the infusion bag package, but this method requires adjustment of the bag making machine for each infusion bag to be stored. There was a problem that the bag-making process became complicated, leading to a decrease in production efficiency.

Patent Document 2 proposes a packaging material for packaging contents that is hard and has protrusions. This packaging material is a laminate of a base material layer, a linear low density polyethylene (L-LDPE) resin layer, a gas barrier layer, and a sealant layer. Examples of the gas barrier layer include a vapor-deposited polyester film on which an inorganic substance (aluminum metal, aluminum oxide, or silicon oxide) is vapor-deposited, a vapor-deposited nylon film, a vinylidene chloride film, an ethylene/vinyl alcohol film, an aluminum foil, and the like. However, the material used for the gas barrier layer does not have sufficient oxygen barrier properties. Furthermore, the above configuration does not provide sufficient pinhole resistance.

Further, Patent Document 3 discloses a vacuum packaging material including aluminum foil and a plastic film on which an inorganic compound is vapor-deposited. Plastic films coated with inorganic compounds are used to maintain barrier properties even when cracks or pinholes occur in aluminum foil. However, since this packaging material uses aluminum foil, it has insufficient pinhole resistance due to bending and the like. Furthermore, plastic films coated with inorganic compounds are generally prone to cracks and pinholes.

Japanese Patent Application Publication No. 8-216325 Japanese Patent Application Publication No. 2005-119063 Japanese Patent Application Publication No. 2006-036272

The present invention has been made in view of the above-mentioned problems, and has been made in view of the above-mentioned problems regarding packaging materials used for medical packaging bags such as infusion bags. An object of the present invention is to provide a laminate for packaging material that has excellent properties and pinhole resistance and can be produced at a relatively low cost.

As a means for solving the above problems, the invention according to claim 1 of the present invention provides a laminate for packaging material formed by sequentially laminating a base material layer, a barrier layer, and a sealant layer, comprising:
The base layer is a biaxially oriented polypropylene film,
The barrier layer consists of a biaxially stretched polyester film and a barrier treatment layer,
The base layer and the barrier layer are in close contact with each other via a first laminate layer made of an extruded laminate layer,
The barrier layer and the sealant layer are in close contact with each other via a second laminate layer,
The sealant layer is composed of two or more sealant layers including at least a first sealant layer and a second sealant layer,
The first sealant layer in contact with the second laminate layer is made of linear low-density polyethylene (L-LDPE) with a density of 0.91 to 0.94, and has a higher molecular weight than the sealant layers after the second sealant layer. , the sealant layers after the second sealant layer are made of linear low-density polyethylene (L-LDPE) with a density of 0.91 to 0.94, and have higher low-temperature sealing properties than the first sealant layer,
A laminate for packaging material, characterized in that the adhesion strength between the base layer and the barrier layer via the extruded laminate layer is 1.0 N/15 mm or more and 5.0 N/15 mm or less. be.
Here, the adhesion strength is measured using a 15 mm wide sample under conditions of a tensile speed of 300 mm/min and 90 degree peeling.

In the invention according to claim 2 , the first laminate layer and the second laminate layer are both made of extruded laminate layers,
The laminate for packaging material according to claim 1 , wherein the resin constituting the extruded laminate layer is a resin whose main material is low-density polyethylene.

In the invention according to claim 3 , the first laminate layer and the second laminate layer are both made of extruded laminate layers,
The laminate for packaging material according to claim 1 or 2 , wherein the stiffness after all the layers are laminated is 0.35N or less.
Here, the stiffness is determined by making a loop using a sample with a width of 15 mm and a length of 100 mm, and measuring the repulsion strength when pushed with a loop stiffness tester at a pushing length of 10 mm.

According to the present invention, a packaging material laminate can be obtained that has excellent puncture strength, barrier properties, bending resistance, and pinhole resistance, and can be produced at a relatively low cost. Therefore, it is possible to obtain a packaging material that is highly resistant to vibrations during the transportation process, and that pinholes are less likely to occur when packaging bags rub against each other or against cardboard, or when the vibrations of bent parts rub against the protrusions of the contents. can.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic cross-sectional view which illustrates the laminated body for packaging materials of 1st Embodiment based on the laminated body for packaging materials of this invention. FIG. 2 is a schematic cross-sectional view illustrating a laminate for packaging material according to a second embodiment of the laminate for packaging material of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, the laminated body for packaging materials based on embodiment of this invention is demonstrated using drawings. Identical components are given the same reference numerals unless there is a reason for convenience. In each drawing, the thickness and proportions of components may be exaggerated for ease of viewing, and the number of components may be reduced. Further, the present invention is not limited to the following embodiments as they are, and can be embodied through appropriate combinations and modifications without departing from the spirit.

FIG. 1 is a schematic cross-sectional view illustrating a laminate 10 for packaging materials according to a first embodiment of the laminate for packaging materials of the present invention. The packaging material laminate 10 is a laminate in which a base material layer 11, a barrier layer 12, and a sealant layer 13 are laminated in this order. The base material layer 11 is made of biaxially oriented polypropylene, and the barrier layer 12 is composed of a biaxially oriented polyester film 12a and a barrier treatment layer 12b, and the base material layer 11 and barrier layer 12 are formed using an extrusion lamination method. They are in close contact with each other through an extruded laminate layer (first laminate layer) 14. Further, the barrier layer 12 and the sealant layer 13 are in close contact with each other via the second laminate layer 15.
In addition, when bag making processing is performed, the base material layer 11 side becomes the outer layer side, and the sealant layer 13 side becomes the inner layer side.

Further, in the packaging material laminate 10 of the first embodiment, the adhesion strength between the base material layer 11 and the barrier layer 12 via the extruded laminate layer 14 is 1.0 N/15 mm or more and 5.0 N/15 mm or less. It is characterized by Here, the adhesion strength was measured using a sample with a width of 15 mm at a tensile speed of 300 mm/min and under the conditions of 90 degree peeling.

The base material layer 11 is preferably a biaxially oriented polypropylene film for reasons such as heat resistance during sealing during filling, stiffness of the film itself, and puncture resistance. A thickness of about 30 to 60 μm can be suitably used. If necessary, a printed layer (not shown) on which characters, pictures, etc. are applied can be provided on the inside or outside of the base layer 11.

The barrier layer 12 is a layer that provides gas barrier properties, and is made by adding a barrier treatment layer 12b to a biaxially stretched polyester film 12a. As the barrier treatment layer 12b, aluminum vapor deposition or a thin film layer of transparent metal oxide such as silica or alumina can be suitably used. The thickness of the biaxially stretched polyester film is preferably about 12 μm.

In addition to the above-mentioned layer, a gas barrier protective layer (not shown) may be further coated as the barrier treatment layer 12b in order to prevent the barrier layer from cracking due to rubbing during lamination processing or bending of the laminate. . The gas barrier protective layer is mainly composed of metal oxides, etc., and is composed of Si(OR ¹ ) ₄ and R ² Si(OR ³ ) ₃ (R ¹ and R ³ are CH ₃ , C ₂ H ₅ , C ₂ H ₄ OCH ₃ Heat-drying of a thin film consisting of a silicon compound represented by a hydrolyzable group such as ( ^R2 is an organic functional group) or its hydrolyzate, and a gas barrier coating solution whose main components are a water-soluble polymer having a hydroxyl group. It is a film. The thickness of the gas barrier protective layer is preferably 0.1 to 100 μm, more preferably 0.1 to 3 μm.

The base material layer 11 and the barrier layer 12 are in close contact with each other via an extrusion laminate layer (first laminate layer) 14 formed using an extrusion lamination method. The extrusion lamination method is a method in which molten polyethylene or polypropylene is sandwiched as an extruded resin layer between a pair of plastic films (in this application, the base layer 11 and the biaxially stretched polyester film 12a) and the films are bonded together by hydrogen bonding.

The adhesion strength of plastic films depends on the thickness and temperature of the extruded resin layer, the formation of a very thin anchor coat (AC) layer, which is a very thin adhesive or adhesion aid, on at least one of the pair of plastic films, and the thickness of the anchor coat (AC) layer, which is a very thin adhesive or adhesion aid, and the thickness of the extruded resin layer. can be adjusted by performing corona treatment under various conditions. In the present application, by these methods, the adhesion strength between the base material layer 11 and the barrier layer 12 is improved by adhesion between the easily adhesive extruded resin layer made of plastic resin mainly made of polyethylene and the easily adhesively treated biaxially stretched polyester film 12a. , adjust the adhesion strength to 1.0 to 5.0N/15mm.

When the adhesion strength is 5.0 N/15 mm or less, the interlayers are likely to float due to transport vibrations, especially at the bent part of the film, and each layer becomes thinner, resulting in lower stiffness, which improves the shape followability of the film, and Tears and pinholes are less likely to occur. Further, if the interlayer adhesion strength is less than 1.0 N/15 mm, the film tends to be excessively lifted, and the seal strength is extremely deteriorated due to triangular peeling at the sealed portion after bag making. Therefore, the adhesion strength between the base layer 11 and the barrier layer 12 is preferably in the range of 1.0 to 5.0 N/15 mm.

The sealant layer 13 is a layer that provides heat-sealing properties, as well as bending resistance and puncture resistance, and can be made of a polyolefin resin mainly composed of low-density polyethylene. Linear low-density polyethylene resin (L -LDPE) can be suitably used.

FIG. 2 is a schematic cross-sectional view illustrating a laminate 20 for packaging materials according to a second embodiment of the laminate for packaging materials of the present invention. In the packaging material laminate 20, the sealant layer 13 is composed of at least two sealant layers, and the first sealant layer 13a on the outer layer side in contact with the second laminate layer 15 has a density of 0.91 to 0.94. It is made of linear low density polyethylene (L-LDPE) and has a higher molecular weight than the sealant layers after the second sealant layer 13b, and the sealant layers after the second sealant layer 13b have a density of 0.91 to 0.94. It is characterized by being made of linear low-density polyethylene (L-LDPE) and having higher low-temperature sealing properties than the first sealant layer 13a. That is, good sealing strength is exhibited even under low temperature conditions during bag manufacturing, sealing failure of packaging bags is less likely to occur, and transportation durability is also improved.

As described above, in the packaging material laminate 20 of the second embodiment, the outer layer side has a high molecular weight and low density first sealant layer 13a with a density of 0.91 to 0.94, and the inner layer side has low-temperature sealing properties. At least two sealant layers are laminated, each consisting of a low-density second sealant layer 13b with a high density of 0.91 to 0.94, so even if the inner layer is rubbed and damaged, the outer layer is resistant to bending and abrasion. , resulting in a laminate with high bending resistance and pinhole resistance.

In both the packaging material laminate 10 of the first embodiment and the packaging material laminate 20 of the second embodiment, the method of laminating the second laminate layer 15 in which the barrier layer 12 and the sealant layer 13 are laminated is particularly limited. For example, it is preferable to use a dry lamination method using a two-component reactive polyester resin adhesive or an extrusion lamination method in which low-density polyethylene is sandwiched as an extruded resin layer, similar to the lamination of the base layer 11 and barrier layer 12. can be used.

Both the packaging material laminate 10 of the first embodiment and the packaging material laminate 20 of the second embodiment have a stiffness of 0.35 N or less when measured using a loop stiffness tester. It is preferable. Here, stiffness is determined by making a loop using a sample with a width of 15 mm and a length of 100 mm, and measuring the repulsion strength with a loop stiffness tester when this loop is pushed in by 10 mm (pushing length is 10 mm). More preferably, the stiffness is in the range of 0.25N to 0.35N.

If the stiffness is too high, the bag will bend without following the shape of the bag when it is filled with contents, so a large load will be applied to the bent part during transportation, etc., resulting in tears and pinholes in the film that makes up the laminate. is more likely to occur. On the other hand, if the film constituting the laminate is too thin and the stiffness is too low, the followability against bending and transport vibrations will improve, but the strength against tension and puncture will become weak.

The packaging material laminate 10 of the first embodiment of the present invention or the packaging material laminate 20 of the second embodiment is slit into desired dimensions and made into a packaging bag. The shape of the bag is arbitrary, such as a two-sided sealed bag, a three-sided sealed bag, a four-sided sealed bag, etc. For example, an infusion bag for medical institutions is placed in the finished packaging bag and packaged. Alternatively, a gas absorbent such as an oxygen absorbent or a carbon dioxide absorbent may be enclosed and packaged.

The above-mentioned packaging bag uses a polyester film that has been subjected to barrier treatment as a barrier layer, and the adhesion strength between the base material layer and the barrier layer is selected within a suitable range, so it is easy to use during transportation, etc. Even after a long period of storage, pinholes and puncture wounds are unlikely to appear on the packaging bag, and the gas barrier properties are also resistant to deterioration, so it can withstand long-term storage.

The present invention will be described in more detail below based on Examples and Comparative Examples, but the scope of the present invention is not limited to the following Examples without departing from the gist of the present invention.

<Example 1>
As the base material layer 11, a biaxially oriented polypropylene (OPP) film with a thickness of 50 μm was prepared. As the barrier layer 12, a 12 μm thick PET film (a type of biaxially stretched polyester film 12a) is coated with an aluminum vapor deposited layer of about 70 nm as a barrier treatment layer 12b, and a gas barrier protective layer made of SiO ₂ and polyvinyl alcohol is further formed. A coated film was prepared. Next, the base material layer 11 and the PET film 12a side of the barrier layer 12 are brought into close contact with each other by an extrusion lamination method using a low density polyethylene resin having a density of 0.91 as an extruded resin layer, thereby producing a composite film (1). did. The thickness of the extruded resin layer was 15 μm.

As the sealant layer 13, a single-layer linear low-density polyethylene (L-LDPE) film (thickness: 60 μm) was prepared. Next, the barrier treated layer 12b side of the barrier layer 12 of the composite film (1) and the sealant layer 13 are coated with a two-component reactive polyester resin adhesive at 2 to 3 g/m ² on the barrier treated layer 12b side. (solid content) was coated and bonded to the sealant layer 13 by a dry lamination method to produce the laminate of the first embodiment shown in FIG. 1, which was the laminate of Example 1.

<Example 2>
The same composite film as the composite film (1) produced in Example 1 was prepared as the composite film consisting of the base material layer 11 and the barrier layer 12. As the sealant layer 13, the first sealant layer 13a on the outer layer side (composite film (1) side) is made of L-LDPE with a density of 0.92, and the second sealant layer 13b on the inner layer side is made of L-LDPE with a density of 0.91. They were laminated at a film thickness ratio of 1:2 to create a two-layer sealant layer with a total thickness of 60 μm.

Next, the barrier treated layer 12b side of the barrier layer 12 of the composite film (1) and the first sealant layer 13a of the two sealant layers 13 were dry laminated under the same conditions as in Example 1. They were bonded together to produce a laminate of the second embodiment shown in FIG. 2, which was a laminate of Example 2.

<Comparative example 1>
As the base material layer 11, a biaxially oriented polypropylene (OPP) film with a thickness of 30 μm was prepared. As the barrier layer 12, a film was prepared by attaching a 6 μm thick aluminum foil to a 25 μm thick stretched nylon film as the barrier treatment layer 12b. Next, the base material layer 11 and the stretched nylon film side of the barrier layer 12 are brought into close contact with each other by an extrusion lamination method using a low-density polyethylene resin and an anchor coat (1.0 g/m ² ), and the composite film (2 ) was created. The thickness of the extruded resin layer was 15 μm.

As the sealant layer 13, a single-layer linear low-density polyethylene (L-LDPE) film (thickness: 50 μm) was prepared. Next, the aluminum foil side of the barrier layer 12 of the composite film (2) and the sealant layer 13 were bonded together by a dry lamination method under the same conditions as in Example 1 to obtain a laminate of Comparative Example 1.

<Comparative example 2>
The same base material layer 11 as in Comparative Example 1 was prepared, and as the barrier layer 12, the composite film (1) produced in Example 1 without forming a gas barrier protective layer was used, and these were dry laminated. A composite film (3) was produced by laminating the two sheets together. As the sealant layer 13, a two-layer sealant layer having a total thickness of 60 μm was prepared in the same manner as in Example 2. The composite film (3) and the sealant layer 13 were bonded together by a dry lamination method under the same conditions as in Example 1 to obtain a laminate of Comparative Example 2.

<Comparative example 3>
The same base material layer 11 as in Comparative Example 1 was prepared, and the same barrier layer 12 as in Example 1 was prepared, and these were bonded together by dry lamination to produce a composite film (4). As the sealant layer 13, a single-layer linear low-density polyethylene (L-LDPE) film (thickness: 60 μm) with a density of 0.925 was prepared. Next, the composite film (4) and the sealant layer 13 made of a single layer of L-LDPE film with a density of 0.925 were laminated together by the same dry lamination method as in Example 1 to form the laminate of Comparative Example 3. And so.

The layer structures of the laminates of Examples 1 and 2 and Comparative Examples 1 to 3 produced above are briefly summarized in Table 1.

[Evaluation method]
(Adhesion strength)
A sample was cut to a width of 15 mm, and the adhesion strength between the base layer and the barrier layer was measured under conditions of a tensile speed of 300 mm/min and 90 degree peeling.

(Koshi strength)
A loop was made using a sample cut to a width of 15 mm and a length of 100 mm, and the repulsion strength when pressed was measured using a loop stiffness tester.

(Piercing strength)
A needle with a diameter of 1 mm and a tip of 0.5 R was pierced into the test material laminate at a speed of 50 mm per minute, and the maximum strength until penetration was measured. Measurements were made from two directions: from the base material layer side and from the sealant layer side.

(Oxygen barrier property)
A 1000 mL infusion bag was put into the contents as a packaging bag and subjected to a transportation vibration test (JIS Z0232 standard, 90 minutes), and then measured using the MOCON method in accordance with JIS K7126 in an environment with a temperature of 30°C and humidity of 70%. .

(Bending resistance)
An A4 size laminated film was run on a gelboflex tester at 5°C/2000 times and 5°C/3000 times (severe conditions). The number of holes generated was counted.

[Evaluation results]
Table 2 shows the evaluation results of adhesion strength, stiffness strength, puncture strength, and oxygen barrier property, and Table 3 shows the evaluation results of bending resistance.

As shown in Tables 2 and 3, the base material layer and barrier layer were extrusion laminated with the layer structure of the present invention as in Examples 1 and 2, and the adhesion strength was 1.0 to 3.0 N/15 mm. By setting a lower limit and an upper limit, the puncture strength was equivalent to that of the aluminum foil laminated packaging material of Comparative Example 1, and the pinhole resistance was also excellent. Note that the difference in adhesion strength between Example 1 and Example 2 is within the range of variation between lots. On the other hand, in the configurations of Comparative Examples 2 and 3 in which the adhesion strength was greater than 3.0 N/15 mm, the bending resistance during severe tests was particularly poor, and the resistance to seepage and pinholes was poor.

In the layer structure of the present invention as in Examples 1 and 2, there is an upper limit to the adhesion strength of 3.0N/15mm, but by suppressing the adhesion strength to a suitable range in this way, the force applied to the film during bending can be reduced. is thought to be dispersed, making it difficult to tear. Adhesion strength can be ensured by a second laminate layer that laminates the sealant layer.

In addition, in the layer structure of the present invention as in Examples 1 and 2, instead of using a biaxially stretched nylon film or aluminum foil as in Comparative Example 1, a PET film coated with aluminum is used, which provides high barrier properties and prevents deterioration. It becomes a packaging material that is difficult to clean, and can be produced at a relatively low cost.

Furthermore, by setting the stiffness to 0.35N or less, the rigidity is lower (softer) and less likely to tear, resulting in high bending resistance and less occurrence of pinholes. We were able to create a laminate for packaging materials that maintains strength and good barrier properties.

The laminate for packaging materials of the present invention can be applied not only to packaging bags for medical infusion bags, but also to products that undergo vacuum packaging or deaeration packaging, such as electronic components and industrial products.

10... First embodiment of the laminate for packaging materials of the present invention 20... Second embodiment of the laminate for packaging materials of the present invention 11... Base material layer 12... ... Barrier layer 12a ... Biaxially stretched polyester film 12b ... Barrier treatment layer 13 ... Sealant layer 13a ... First sealant layer 13b ... Second sealant layer 14 ...Extrusion laminate layer (first laminate layer)
15...Second laminate layer

Claims (3)

A laminate for packaging material formed by sequentially laminating a base material layer, a barrier layer, and a sealant layer,
The base layer is a biaxially stretched polypropylene film,
The barrier layer consists of a biaxially stretched polyester film and a barrier treatment layer,
The base layer and the barrier layer are in close contact with each other via a first laminate layer made of an extruded laminate layer,
The barrier layer and the sealant layer are in close contact with each other via a second laminate layer,
The sealant layer is composed of two or more sealant layers including at least a first sealant layer and a second sealant layer,
The first sealant layer in contact with the second laminate layer is made of linear low-density polyethylene (L-LDPE) with a density of 0.91 to 0.94, and has a higher molecular weight than the sealant layers after the second sealant layer. , the sealant layers after the second sealant layer are made of linear low-density polyethylene (L-LDPE) with a density of 0.91 to 0.94, and have higher low-temperature sealing properties than the first sealant layer,
Adhesion strength between the base layer and the barrier layer via the extruded laminate layer is 1.0 N/15 mm or more and 5.0 N/15 mm or less,
A laminate for packaging material characterized by:
Here, the adhesion strength is measured using a 15 mm wide sample under conditions of a tensile speed of 300 mm/min and 90 degree peeling. The first laminate layer and the second laminate layer are both made of extruded laminate layers,
The resin forming the extruded laminate layer is a resin whose main material is low-density polyethylene.
The laminate for packaging material according to claim 1 , characterized in that: The first laminate layer and the second laminate layer are both made of extruded laminate layers,
The stiffness after laminating all layers is 0.35N or less,
The laminate for packaging material according to claim 1 or 2 , characterized in that:
Here, the stiffness is determined by making a loop using a sample with a width of 15 mm and a length of 100 mm, and measuring the repulsion strength when pushed with a loop stiffness tester at a pushing length of 10 mm.

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