JP2022130084A - Packaging material excellent in straight cutting property, and package - Google Patents

Abstract

To provide a packaging material excellent in straight cutting property, and a package using the packaging material.SOLUTION: This packaging material has an outer layer, an intermediate layer, and a sealant layer laminated in this order, where at least one of the intermediate layer and the sealant layer has a notch lag of 1 mm or less of a film to be measured by the below-mentioned measuring method. <MEASURING METHOD> A sample is prepared by cutting out a film into a rectangle 150 mm in the MD direction, and 50 mm in the TD direction, and by forming a notch at the midpoint of one of two sides in the TD direction, and a Trouser test is executed at a test speed of 200 mm/min according to JIS K 7128-1 to decide the distance between a cutting position on the side where a notch is not formed, out of two sides in the TD direction, a midpoint as a film notch lag.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD The present invention relates to a packaging material having excellent straight cutting properties by appropriately combining films used for the packaging material. The present invention also relates to a package using the packaging material.

Flexible packaging, which is a package using laminated film, is lighter than metal cans, so transportation costs and environmental impact are small. volume can be reduced. In addition, by changing the film structure of flexible packaging, it is possible to easily provide barrier properties against air and water vapor, and to provide light-shielding properties.

Conventional soft packaging does not move straight when opened by hand, and the front and back of the package may be cut diagonally in different directions. As a result, a large force is required to cut off a part of the package when the package is opened, and the problem is that the contents of the package scatter. Therefore, it is important to provide the package with good openability. Tools such as scissors can be used as a method of cutting the package straight, but this is not preferable depending on the contents because the contents adhere to the tool.

As a method for imparting straight cuttability to the package, there is, for example, a method using a uniaxially stretched sealant film (Patent Document 1). and is not suitable for practical use. There is also a method of imparting straight cuttability by laser processing (Patent Document 2), but it is difficult to put into practical use because of the use of special ink and laser processing, which makes the package expensive.

Japanese Patent No. 6351259 JP 2020-55633 A

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and an object of the present invention is to provide a packaging material excellent in straight cutting property and a package using the packaging material.

One aspect of the present invention for solving the above problems is a packaging material in which an outer layer, an intermediate layer, and a sealant layer are laminated in this order, and at least one of the intermediate layer and the sealant layer is measured by the following measurement method. A packaging material having a film notch displacement of 1 mm or less.
<Measurement method>
Cut the film into a rectangle with an MD direction of 150 mm and a TD direction of 50 mm, create a sample with a notch formed at the midpoint of one of the two sides in the TD direction, and test at a test speed of 200 mm / min according to JIS K 7128-1. A trouser test is carried out, and the distance between the cutting position on the side where no notch is formed and the midpoint of the two sides in the TD direction is defined as "film notch deviation".

ADVANTAGE OF THE INVENTION According to this invention, the package body using the packaging material excellent in straight cutability and the said packaging material can be obtained.

Explanatory drawing of a test piece used for straight cutting property evaluation of film Explanatory drawing of a test piece after a film straight cutting property evaluation test Explanatory drawing of a test piece used for straight cutability evaluation of packaging material Explanatory drawing of the test piece after the straight cutting property evaluation test of the packaging material Explanatory drawing of samples used for hand-opening evaluation of packages

Next, the packaging material of the present invention will be described in detail. The packaging material comprises an outer layer, an intermediate layer and a sealant layer in that order.

[Film combination]
At least one of the intermediate layer and the sealant layer is made of a film having a straight cutting property, which will be described later. That is, the combination of the outer layer, the intermediate layer and the sealant layer does not satisfy the following requirements (a) and (b).
(a) The outer layer is a film having straight cutting properties, the intermediate layer is a film having no straight cutting properties, and the sealant layer is a film having no straight cutting properties.
(b) The outer layer is a film that does not have straight cutting properties, the intermediate layer is a film that does not have straight cutting properties, and the sealant layer is a film that does not have straight cutting properties.

[Straight cutability of film]
FIG. 1 is an explanatory diagram of a test piece used for evaluation of film straight cutability, and FIG. 2 is an explanatory diagram of a test piece after straight cutability evaluation test of film. The straight cutting property of a film indicates the property of being cut straight when torn. In the present specification, straight cutability is determined by the value of "film notch deviation" measured by the following method.

[Film notch deviation measurement]
It has a rectangle with 150 mm in the MD direction and 50 mm in the TD direction. As 12, a test piece 10 is prepared on which a straight line 13 connecting the midpoints 11 and 12 is drawn. Using this test piece 10, a trouser test is performed at a test speed of 200 mm/min according to JIS K7128-1.

In the test piece 20 obtained by performing the trouser test, when the intersection of the tear curve generated by the trouser test and the side on which the middle point 11 is provided is the intersection 14, the middle point 11 and the line segment with the intersection 14 as the end point The length of 15 is defined as "film notch deviation". Although the point 14 is shown on the left side of the middle point 11 in FIG. 2, the intersection point 14 may occur on the right side of 11 in actual tearing. In this case, as in FIG. 2, the length of the line segment 15 whose endpoints are the midpoint 11 and the intersection 14 is defined as "film notch deviation".

A film having a notch deviation of 1 mm or less on the test piece 20 measured by the above method is defined as a film having straight cutting properties. A film having a notch displacement of more than 1 mm or having a tear line that bends greatly and is torn at the side in the MD direction is defined as a film that does not have straight cutting properties.

[Outer layer, intermediate layer]
The films used for the outer layer and the intermediate layer must be selected according to the required properties of the packaging material, and polyolefin films, polyester films and polyamide films are particularly preferred. A plurality of materials may be mixed and used in order to impart straight cuttability. A specific example is shown. Mixture of propylene homopolymer and ethylene-propylene random copolymer, mixture of propylene homopolymer and ethylene-propylene rubber, mixture of propylene homopolymer, ethylene-propylene random copolymer and ethylene-propylene rubber as polyolefin film, propylene homopolymer and polyethylene, a mixture of ethylene-propylene copolymer and polyethylene, and the like. As polyester films, mixtures of polyethylene terephthalate and polybutylene terephthalate, mixtures of polyethylene terephthalate and acid-modified polyethylene terephthalate, mixtures of polyethylene terephthalate and acid-modified polybutylene terephthalate, and mixtures of polybutylene terephthalate and acid-modified polyethylene terephthalate Mixtures, mixtures of polybutylene terephthalate and acid-modified polybutylene terephthalate, mixtures of polyethylene terephthalate and polyarylates, mixtures of polybutylene terephthalate and polyarylates, and the like may be used. A mixture of 6-nylon and 6,6-nylon as a polyamide film, a mixture of 6-nylon and 6,12-nylon, a mixture of 6-nylon and poly-meta-xylene adipamide, 6,6-nylon and 6,12- Mixtures of nylon, 6,6-nylon and polymetaxylene adipamide, 6,12-nylon and polymetaxylene adipamide, and the like may be used.

The thickness of the film used for the outer layer or the intermediate layer is not particularly limited, but if the thickness is too small, pinhole resistance, impact resistance, heat resistance and stiffness are impaired, which is not preferable. If the thickness is too large, it is not preferable because it results in excessive packaging and an increase in cost. A polyolefin film having a thickness of 10 to 40 μm, a polyester film having a thickness of 10 to 30 μm, and a polyamide film having a thickness of 10 to 30 μm are preferably used.

The films used for the outer layer and the intermediate layer may be laminated with functional layers. Examples of lamination of functional layers include a method of vapor-depositing aluminum, alumina (AlOx), and silica (SiOx) using a physical vapor deposition method (PVD method), a chemical vapor deposition method (CVD method), or the like. , polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, and other gas barrier resins are applied by a wet process.

[Sealant layer]
A thermoplastic resin is preferably used for the sealant layer from the viewpoint of heat-sealing suitability, and a polyethylene-based unstretched film or a polypropylene-based unstretched film is particularly preferable because the temperature at which the heat-sealing property is exhibited is low. Further, in order to obtain straight cuttability, a method of mixing other materials or a method of uniaxial stretching may be used as long as the heat-sealing property is not impaired. As an example, a mixture of polyethylene and a cyclic olefin copolymer, a mixture of polypropylene and a cyclic olefin copolymer, a mixture of polyethylene and ethylene-vinyl alcohol copolymer, a mixture of polyethylene and polyamide, a mixture of polypropylene and polyamide, etc. may be used. Also, a film made of polyolefin alone or a mixture of the above may be uniaxially stretched and used.

For the sealant layer, in order to impart properties other than straight cutting properties, a plurality of materials may be mixed and used as long as the heat sealing properties and straight cutting properties are not impaired. For example, a mixture of polypropylene, ethylene propylene rubber and cyclic olefin copolymer, a mixture of polypropylene, cyclic olefin copolymer and calcium oxide, a mixture of polypropylene, ethylene propylene rubber, cyclic olefin copolymer and calcium oxide, a mixture of polyethylene, cyclic olefin copolymer and calcium oxide. , a mixture of polyethylene, a cyclic olefin copolymer and zinc oxide, a mixture of polypropylene, a cyclic olefin copolymer and zinc oxide, a mixture of polypropylene, ethylene propylene rubber, a cyclic olefin copolymer and zinc oxide, and the like.

The thickness of the sealant layer is not particularly limited, but if the thickness is too small, the seal strength, bag breakage resistance, stiffness, and heat resistance will be impaired. Unfavorable because it increases A sealant layer having a thickness of 30 to 150 μm is preferably used.

The film used in the present invention may be subjected to a surface modification treatment in order to improve suitability for subsequent processes. For example, in order to improve the printability when using a single film or to improve the lamination aptitude when using a laminate, it is possible to apply a surface modification treatment to the surface that comes into contact with other substrates. For surface modification, it is possible to suitably use a method that expresses functional groups by oxidizing the film surface, such as corona discharge treatment, plasma treatment, flame treatment, etc., and modification by a wet process such as coating of an easy-adhesion layer. is.

The laminated structure of the packaging material of the present invention must be appropriately selected according to the required properties of the packaging material, such as the size and impact resistance that can accommodate the weight of the contents to be packaged, and the visibility of the contents. A typical structure is PET/ONy/CPP, PET/ONy/PE, ONy/PET/CPP, ONy/PET/PE, OPP/PET/CPP, ONy/ONy in the order of outer layer/intermediate layer/sealant layer. /PE, PET/PET/CPP, but not limited to the above representative configurations.

The usual dry lamination method, in which each layer is laminated using an adhesive, can be suitably used as the manufacturing method for the packaging material, but if necessary, a non-solvent lamination method that does not use a solvent or a method that directly extrusion laminates each layer can also be adopted. can do Although the type of adhesive used in the dry lamination method and the non-solvent lamination method is not particularly limited, polyether adhesives, polyester adhesives and polyurethane adhesives are preferably used. The laminating resin used for extrusion lamination is not particularly limited, but polyethylene, ethylene methacrylic acid copolymer, ionomer, ethylene vinyl acetate copolymer, ethylene acrylic acid copolymer, and ethylene ethyl acrylate copolymer can be used. It is preferably used. In addition, in order to increase the adhesive strength in extrusion lamination, an adhesion aid called an anchor coat may be applied and used.

FIG. 3 is an explanatory diagram of a test piece used for evaluating the straight cutting property of the packaging material, and FIG. 4 is an explanatory diagram of the test piece after the straight cutting property evaluation test of the packaging material. The straight cutting property of a packaging material indicates the property of being cut straight when torn. In this specification, the straight cutability of the packaging material is determined by the value of "notch displacement of the packaging material" measured by the following method.

[Straight cutability of packaging material]
It has a rectangle with 63 mm in the MD direction and 75 mm in the TD direction. As 32, a test piece 30 with a straight line 33 connecting the midpoints 31 and 32 is drawn. Using the test piece 30, the Elmendorf test is performed. The test is conducted according to JIS K 7128-2.

In the test piece 40 obtained by performing the Elmendorf test, when the intersection of the tear curve generated by the Elmendorf test and the side on which the midpoint 31 is provided is set to the intersection 34, a line segment 35 having the point 31 and the intersection 34 as the endpoints The length of is defined as "packaging material notch deviation".

A packing material having straight cutability is defined as a packing material having a notch deviation of 1 mm or less on the test piece 40 measured by the above method. A film in which the notch displacement of the test piece 40 is greater than 1 mm or the tear line is greatly bent and the tear ends at the MD direction side is used as a packaging material that does not have straight cutting properties.

By using a film having straight cutability for at least one of the intermediate layer and the sealant layer of the packaging material, a packaging material having straight cutability can be obtained.

The packaging material according to the present embodiment uses the sealant layer as a sealing material, and can be used for packaging such as flat bags, three-sided bags, folding bags, gusseted bags, standing pouches, pouches with spouts, and pouches with beaks. The form of bag making is not particularly limited. In addition, in order to improve the openability of the package, a method of making a notch, a method of performing laser processing, and a method of laminating a film to assist tearing may be used.

As described above, the packaging material according to the present embodiment includes an outer layer, an intermediate layer, and a sealant layer in this order, and at least one of the intermediate layer and the sealant layer uses a film having straight cutting properties. Excellent in nature. Moreover, the packaging material according to the present embodiment can be sealed with a sealant layer to form a packaging bag.

Examples of the present invention will be described in detail below, but the present invention is not limited only to the following examples.

Materials for each layer used in the examples will be described. Two types of films were prepared for the outer layer. As the polyester film A, "PC12" manufactured by Unitika Ltd. was used. This film was mainly composed of polyethylene terephthalate, and had a thickness of 12 μm and a notch deviation of 0.8 mm. As the polyester film B, "PET12" manufactured by Unitika Ltd. was used. This film was mainly composed of polyethylene terephthalate, had a thickness of 12 μm, and had a notch deviation of 18.4 mm. Two types of films were prepared for the intermediate layer. As the polyamide film A, "NCBC15" manufactured by Unitika Ltd. was used. This film was a film containing nylon as a main component, and had a thickness of 15 μm and a notch deviation of 0.9 mm. As the polyamide film B, "ONBC15" manufactured by Unitika Ltd. was used. This film was a film containing nylon as a main component, and had a thickness of 15 μm and a notch deviation of 11.1 mm. Two types of films used for the sealant layer were prepared. As the polypropylene film A, "DC061" manufactured by Toyobo Co., Ltd. was used. This film was a film containing polypropylene and an ethylene-propylene copolymer, and had a thickness of 60 μm and a notch deviation of 0.4 mm. As the polypropylene film B, "ZK207" manufactured by Toray Advanced Film Co., Ltd. was used. This film was a film containing polypropylene and an ethylene-propylene copolymer, and had a thickness of 60 μm and a notch deviation of the film of 1.1 mm.

A packaging material was obtained by laminating each layer by a dry lamination method. A commercially available polyurethane adhesive was used as the adhesive. Specifically, 47.6 parts by mass of Takelac A-626 (manufactured by Mitsui Chemicals, Inc.) for polyol, 6.0 parts by mass of Takenate A-50 (manufactured by Mitsui Chemicals, Inc.) for polyisocyanate, solid content concentration adjustment Therefore, an adhesive mixed with 46.4 parts by mass of NC401 solvent (manufactured by Toyo Ink Co., Ltd.), which is an ethyl acetate solvent, was used. After drying the solvent, the adhesive was applied so that the coating amount was 3 g/m 2 , dried, and the layers were laminated in order. After completion of dry lamination, the adhesive was cured by aging in an environment of 50° C. for 4 days to obtain packaging materials of Examples 1-6 and Comparative Examples 1-2.

(Example 1)
A packaging material was used in which polyester film A, polyamide film A, and polypropylene film A were laminated in this order.

(Example 2)
A packaging material in which polyester film A, polyamide film A, and polypropylene film B were laminated in this order was used.

(Example 3)
A packaging material was used in which polyester film B, polyamide film A, and polypropylene film A were laminated in this order.

(Example 4)
A packaging material was used in which polyester film B, polyamide film A, and polypropylene film B were laminated in this order.

(Example 5)
A packaging material was used in which polyester film A, polyamide film B, and polypropylene film A were laminated in this order.

(Example 6)
A packaging material was used in which polyester film B, polyamide film B, and polypropylene film A were laminated in this order.

(Comparative example 1)
A packaging material in which polyester film A, polyamide film B, and polypropylene film B were laminated in this order was used.

(Comparative example 2)
A packaging material was used in which polyester film B, polyamide film B, and polypropylene film B were laminated in this order.

The packaging materials prepared in Examples 1-6 and Comparative Examples 1-2 were evaluated as follows.

[Evaluation of straight cutability of packaging material]
Each of the packaging materials produced in Examples 1 to 6 and Comparative Examples 1 and 2 was evaluated for straight cutability.

Using a rectangular test piece of 63 mm in the MD direction and 75 mm in the TD direction, the Elmendorf test was performed with an Elmendorf tear tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.) to measure the notch displacement of the packaging material. The test was conducted according to JIS K 7128-2. When the notch deviation of the packaging material was 1 mm or less, it was judged to have good straight cutting performance (O), and when it was more than 1 mm, it was judged to have poor straight cutting performance (x).

[Evaluation of cutting performance by hand]
FIG. 5 is an explanatory diagram of a sample used for evaluating the unsealability of the package by hand. Each of the packaging materials produced in Examples 1 to 6 and Comparative Examples 1 and 2 was evaluated for cutability by hand. The packaging material is heat-sealed at 200 ° C., 0.15 MPa, a seal width of 5 mm for 1 second to prepare a three-sided bag, 600 mL of water is added, and one unsealed side is heat-sealed under the same conditions, and the inner size is 200 mm. A sample 50 of ×200 mm was produced. A linear notch 52 was made in the seal portion 51 of the sample 50 so that it could be torn in the MD direction, and the sample was torn open by hand. When the tear lines were aligned on the front and back of the sample when opened, it was judged to be cut easily by hand (○), and when the tear lines were not aligned on the front and back of the sample, it was judged to be poorly cut by hand (×).

Table 1 shows the results of the above evaluations for each layer combination of Examples 1-6 and Comparative Examples 1-2, and Examples 1-6 and Comparative Examples 1-2.

In Examples 1 to 6, a film having excellent straight cutting property was used for at least one of the intermediate layer and the sealant layer. Met.

In Comparative Example 1, a film having straight cuttability was used for the outer layer, but since films not having straight cuttability were used for both the intermediate layer and the sealant layer, the straight cuttability of the packaging material was poor. The packaging body was inferior in the hand-opening property.

In Comparative Example 2, films having no straight cuttability were used for all of the outer layer, the intermediate layer, and the sealant layer, so that the straight cuttability of the packaging material was poor, and the packaging body was also inferior in hand-openability. .

Since the sealant layer is thicker than the outer layer and the intermediate layer, it has a greater effect on tear behavior than the other layers. Therefore, in Examples 1, 3, 5, and 6, by using a film having straight cutting property for the sealant layer, the straight cutting property of the packaging material was improved. Further, in Examples 1 to 4, a film having a straight cutting property was used for the intermediate layer, which is the layer adjacent to the sealant layer. As a result, the straight cuttability of the intermediate layer assists the straight cuttability of the sealant layer when the packaging material is torn, thereby improving the straight cuttability of the packaging material.

In Comparative Example 1, a film having straight cuttability was used only for the outer layer, but since the outer layer was not adjacent to the sealant layer and could not assist the straight cuttability of the sealant layer, the straight cuttability of the packaging material was not improved. .

INDUSTRIAL APPLICABILITY The present invention is useful for packaging materials and packages.

10 Test piece 11 Middle point 12 Middle point 13 Straight line 14 Intersection 15 Line segment 20 Test piece 30 Test piece 31 Middle point 32 Middle point 33 Straight line 34 Intersection 35 Line segment 40 Test piece 50 Sample 51 Seal portion 52 Notch

Claims (7)

A packaging material in which an outer layer, an intermediate layer, and a sealant layer are laminated in this order,
A packaging material in which at least one of the intermediate layer and the sealant layer has a film notch deviation of 1 mm or less as measured by the following measuring method.
<Measurement method>
Cut the film into a rectangle with an MD direction of 150 mm and a TD direction of 50 mm, create a sample with a notch formed at the midpoint of one of the two sides in the TD direction, and test at a test speed of 200 mm / min according to JIS K 7128-1. A trouser test is carried out, and the distance between the cutting position on the side where no notch is formed and the midpoint of the two sides in the TD direction is defined as "film notch deviation". 2. The packaging material according to claim 1, wherein any one of polyolefin film, polyester film and polyamide film is used for said outer layer and said intermediate layer. 2. The packaging material according to claim 1, wherein the outer layer is a polyester film and the intermediate layer is a polyamide film. The packaging material according to any one of claims 1 to 3, wherein a polyolefin film is used for the sealant layer. The packaging material according to any one of claims 1 to 3, wherein a polypropylene film is used for the sealant layer. The packaging material according to any one of claims 1 to 5, wherein the notch deviation of the packaging material measured by the following measuring method is 1 mm or less.
<Measurement method>
The packaging material was cut into a rectangle with an MD direction of 63 mm and a TD direction of 75 mm, a sample was formed with a notch at the midpoint of one of the two sides in the TD direction, and an Elmendorf test was performed according to JIS K 7128-2, Of the two sides in the TD direction, the distance between the cutting position on the side on which no notch is formed and the midpoint is defined as the "notch displacement of the packaging material". A package using the packaging material according to any one of claims 1 to 6.

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