JP6816665B2 - Packaging material - Google Patents

Description

The present invention relates to a packaging material comprising a paper base material and a biaxially stretched resin film adhered to the paper base material.

A packaging material for multi-pack is known as a packaging material for grouping a plurality of individual packages into one. For example, the multi-pack paper described in Patent Document 1 is applied to individual packages of refrigerated products and individual packages of frozen products, and is sealed in a state in which a plurality of individual packages are bundled. In this multi-pack paper, the content of rosin sizing agent, the content of polyamide polyamine epichlorohydrin resin, and the content of emulsion sizing agent in the pulp raw material are set to values suitable for increasing the tear strength at the time of wetting. There is.

On the other hand, in addition to obtaining tear strength when wet, the above-mentioned packaging material for multi-packs is also required to have hand-cutting property that can be easily opened by tearing by hand. For example, in the packaging material described in Patent Document 2, in order to suppress changes in physical properties due to humidity, a resin layer containing an olefin resin containing no cyclic structure as a main component and two resins containing a cyclic olefin resin as a main component are used. The resin layer of the packaging material is formed as a multilayer body sandwiched between the layers. Then, for the purpose of improving the hand-cutting property, the packaging material is formed as a laminate of the resin layer of the multilayer body and the paper base material.

JP-A-2002-285500 International Publication WO2014 / 207950

However, in order to obtain hand-cutting property, the toughness of the resin layer is high, and even in the case of a laminate of the resin layer and the paper base material, there is still room for improvement in improving the hand-cutting property. There is. Although reducing the thickness of the resin layer is effective in improving the hand-cutting property, it makes the resin layer easy to stretch and makes it difficult to obtain the strength of the packaging material. Such improvement in hand-cutting property is not limited to packaging materials for multi-packs that bundle packages of frozen products and packages of refrigerated products, but is also a problem common to packaging materials applied to various packages.
An object of the present invention is to provide a packaging material capable of improving hand-cutting property.

The packaging material for solving the above problems is a packaging material comprising a paper base material and a biaxially stretched resin film adhered to the paper base material, and the paper base material is JIS P8113: 2006. The tensile strength in the conforming orientation direction is 15 N / 10 mm or more and 60 N / 10 mm or less, the biaxially stretched resin film has holes on the surface and the inside, and the tensile strength according to JIS P8113: 2006 is 15 N. The tear strength is 100 mN / mm or less when it is 10 mm or more and 60 N / 10 mm or less and no cut is made by the Ermendorf type tear tester method of JIS P8116: 2000.
According to the above-mentioned packaging material, since there are holes on the surface and the inside of the biaxially stretched resin film, it is possible to improve the hand-cutting property of the packaging material.

The tensile strength of the paper base material is 15 N / 10 mm or more and 60 N / 10 mm or less in the orientation direction of the paper base material, which is a range suitable for obtaining hand-cutting property. The tensile strength of the biaxially stretched resin film is also 15 N / 10 mm or more and 60 N / 10 mm or less, which is about the same as that of the paper base material. In a biaxially stretched resin film having holes on the surface and inside, the elongation due to pulling tends to be larger than that in a configuration without such holes. In this respect, in the case of the above-mentioned packaging material, the tensile strength of the biaxially stretched resin film is about the same as that of the paper base material, so that the decrease in hand-cutting property due to the biaxially stretched resin film being easily stretched is suppressed. Be done.

The tear strength of the biaxially stretched resin film formed by stretching or the like is smaller than the tear strength of the paper base material. Therefore, it is almost impossible to measure the tear strength of the biaxially stretched resin film by the JIS P8116: 2000 Ermendorf type tear tester method used for testing the tear strength of a paper substrate. On the other hand, the excessively large tear strength of the biaxially stretched resin film is a major obstacle to improving the hand-cutting property of the packaging material even if the biaxially stretched resin film satisfies the above-mentioned tensile strength. .. In this regard, in the case of the above-mentioned packaging material, the tensile strength of the biaxially stretched resin film is 100 mN / mm or less when no cut is made by the Ermendorf type tear tester method of JIS P8116: 2000, and therefore the tensile strength. By setting both the tear strength and the tear strength, it is possible to more reliably improve the hand-cutting property.

In the packaging material, the ratio of the maximum value of the tear strength to the minimum value of the tear strength is 1 in two directions orthogonal to each other including the orientation direction in the in-plane direction of the biaxially stretched resin film. It may be 0.0 or more and 1.2 or less.

According to the above packaging material, since the variation in the tear strength of the biaxially stretched resin film is suppressed, it is possible to suppress the variation in the hand-cutting property due to the variation in the tear strength of the biaxially stretched resin film. As a result, when using the packaging material, it is possible to reduce the restriction of separately presenting the user in the direction in which the hand-cutting property can be obtained.

In the packaging material, the maximum value may be the tear strength in the orientation direction, and the minimum value may be the tear strength in the direction orthogonal to the orientation direction.
The tear strength of the paper substrate in the orientation direction tends to be smaller than the tear strength in the direction orthogonal to the orientation direction. In this respect, according to the above-mentioned packaging material, the direction showing the minimum value in the tear strength of the biaxially stretched resin film and the direction showing the relatively large tear strength in the paper base material coincide with each other. It is also possible to increase the uniformity of tear strength in the whole. As a result, when using the packaging material, it is possible to reduce the restriction of separately presenting the user in the direction in which the hand-cutting property can be obtained.

In the packaging material, the biaxially stretched resin film has a tensile strength of 15 N / 10 mm or more and 30 N / 10 mm or less according to JIS P8113: 2006 in the orientation direction, and JIS P8113 in a direction orthogonal to the orientation direction. : The tensile strength according to 2006 may be 40 N / 10 mm or more and 60 N / 10 mm or less.

The tensile strength of the paper substrate in the orientation direction is greater than the tensile strength in the direction orthogonal to the orientation direction. In this respect, according to the above-mentioned packaging material, the direction showing a relatively small tensile strength in the biaxially stretched resin film coincides with the direction showing a relatively large tensile strength in the paper base material. It is also possible to increase the uniformity of tensile strength in the entire packaging material. As a result, when using the packaging material, it is possible to reduce the restriction of separately presenting the user in the direction in which the hand-cutting property can be obtained.
In the packaging material, the basis weight of the paper base material may be 85 g / m ² or less.
According to the above-mentioned packaging material, it is possible to suppress the difficulty in obtaining hand-cutting property due to the excessively large basis weight of the paper base material.

The cross-sectional view which shows the cross-sectional structure in one Embodiment of a packaging material.

Hereinafter, an embodiment of the packaging material will be described with reference to FIG. The packaging material includes a resin film 11, an adhesive layer 12, and a paper base material 13 sandwiched between the resin film 11 and the adhesive layer 12.

The resin film 11 includes a pore-containing film 11A and an intermediate layer 11B.
The pore-containing film 11A is a biaxially stretched resin film containing polypropylene-based resin, polyester-based resin, or the like as a main component. The polypropylene-based resin is, for example, a propylene homopolymer, a propylene-ethylene copolymer, a propylene-ethylene-butene copolymer, or the like. Polyester-based resins include polyethylene terephthalate and polyethylene naphthalate.

The pore-containing film 11A has a plurality of pores 11H in which particles 11P are contained on the surface and the inside of the pore-containing film 11A. The thickness of the pore-containing film 11A is, for example, 40 μm or more and 200 μm or less. The diameter of the particles 11P existing in the pores 11H is, for example, 0.1 μm or more and 10 μm or less, and preferably 0.1 μm or more and 2.0 μm or less.

The pore-containing film 11A is formed by stretching an unstretched sheet.
The unstretched sheet is formed by extruding a resin containing particles 11P for generating pores 11H from an extrusion machine and quenching the resin sheet extruded from the extrusion machine with a cooling roll. The unstretched sheet fed at a temperature equal to or higher than the glass transition point is subjected to longitudinal stretching, which is stretching in the feeding direction of the unstretched sheet, and transverse stretching, which is stretching in the direction orthogonal to the feeding direction, that is, that is, Biaxial stretching is applied sequentially. As a result, the pore-containing film 11A is formed from the unstretched sheet.

In the unstretched sheet containing the particles 11P for generating the pores 11H, the particles 11P are separated from the resin component at the time of successive biaxial stretching, whereby the pores 11H inside the particles 11P are generated. The particles 11P for generating the pores 11H are composed of components that are insoluble in the resin components constituting the unstretched sheet. The particles 11P for generating the pores 11H may be inorganic particles or organic particles. The components constituting the inorganic particles are, for example, titanium dioxide, silicon dioxide, barium sulfate, hydrous magnesium silicate, and aluminum silicate. The organic particles are, for example, polyacrylate, polyacrylic rate, polycarbonate, polystyrene, polypropylene.

The pore-containing film 11A satisfies the following [Condition 1] and [Condition 2].
[Condition 1] The tensile strength is 15 N / 10 mm or more and 60 N / 10 mm or less.
[Condition 2] The tear strength is 100 mN / mm or less.
The tensile strength is a value according to JIS P8113: 2006. The tear strength is a value obtained from a seamless test piece without performing a step of making a cut in the test piece by the Elmendorf type tear tester method of JIS P8116: 2000.

The pore-containing film 11A preferably satisfies the following [Condition 3] to [Condition 5].
[Condition 3] The ratio of the maximum value to the minimum value of the tear strength is 1.0 or more and 1.2 or less.
[Condition 4] The direction showing the maximum value of the tear strength is the orientation direction of the fibers on the paper base material 13.
[Condition 5] The direction showing the minimum value of the tear strength is the direction orthogonal to the orientation direction of the paper base material 13.
Either one of the tear strength in the orientation direction and the tear strength in the direction orthogonal to the orientation direction of the pore-containing film 11A is the maximum value of the tear strength, and the other is the minimum value of the tear strength.

The intermediate layer 11B is a layer for adhering the pore-containing film 11A and the paper base material 13. The intermediate layer 11B is composed of, for example, a resin coated on the pore-containing film 11A and an adhesive coated on the pore-containing film 11A. The intermediate layer 11B adheres the pore-containing film 11A and the paper base material 13 by, for example, pressure bonding between the pore-containing film 11A and the paper base material 13.

The method of adhering the pore-containing film 11A and the paper base material 13 is, for example, dry lamination, wet lamination, or non-solvent in which the pore-containing film 11A or the paper base material 13 is bonded by applying an adhesive. It is possible to use lamination. As a method of adhering the pore-containing film 11A and the paper base material 13, it is also possible to use a heat laminate in which the pore-containing film 11A and the paper base material 13 are bonded by thermocompression bonding of a heating roll. When the pore-containing film 11A and the paper base material 13 can be adhered to each other by direct pressure bonding between the pore-containing film 11A and the paper base material 13, the resin film 11 omits the intermediate layer 11B. It is possible, and the resin film 11 may be composed of only the pore-containing film 11A.

The paper base material 13 includes, for example, high-quality paper, medium-quality paper, high-quality coated paper, medium-quality coated paper, high-quality lightweight coated paper, medium-quality lightweight coated paper, white paperboard, yellow paperboard, colored paperboard, and cardboard base paper. For example, paper. At least one surface of the paper substrate 13 may be hydrophobized by a hydrophobizing agent. The paper base material 13 is formed by making a paper material containing pulp with a paper machine or hand-making. The pulp may be any non-wood pulp such as hardwood or coniferous wood pulp, cannabis, flax, kenaf, western hemp, mania hemp, sisal hemp.

The paper base material 13 satisfies the following [Condition 6].
[Condition 6] The tensile strength is 15 N / 10 mm or more and 60 N / 10 mm or less. The tensile strength is a value in the orientation direction according to JIS P8113: 2006.
The paper base material 13 preferably satisfies the following [Condition 7].
[Condition 7] The basis weight is 85 g / m ² or less.

The adhesive layer 12 has a function of adhering to the application target of the packaging material and the paper base material 13. For the adhesive layer 12, for example, various adhesives such as natural type, synthetic type, pressure sensitive type and solvent volatile type can be used.

The packaging material may further include a coating layer on the surface of the pore-containing film 11A, which is the surface of the packaging material. The coating composition may be an inorganic pigment or an organic pigment. Inorganic pigments include clay pigments, calcium carbonate, titanium dioxide, aluminum hydroxide, satin white, magnesium carbonate, calcium sulfate, zinc oxide, silicic acid, silicate, barium sulfate and the like. Organic pigments include styrene-based plastic pigments and urea-based plastic pigments. Since the pore-containing film 11A can enhance the acceptability of inorganic pigments and organic pigments as compared with the film not provided with pores 11H, it is also possible to improve the printability of the packaging material.

[Example 1]
Next, the packaging material of Example 1 will be described below.
As the pore-containing film 11A, a biaxially stretched polypropylene film (product name: STS50, manufactured by Yupo Corporation) having particles contained therein on the surface and inside was used. Further, as the paper base material 13, high-quality paper having a basis weight of 40 g / m ² was prepared.

A molten low-density polyethylene (Mirason 11P (registered trademark), manufactured by Mitsui Chemicals, Inc.) is extruded from a slit die between the air-containing pore film 11A and the paper base material 13, and air-containing through the intermediate layer 11B. The pore film 11A and the paper base material 13 were laminated to obtain the packaging material of Example 1. The thickness of the film-formed intermediate layer 11B was 15 μm.

Next, an adhesive (product name: Oliveine (registered trademark) BPW6166) was applied to a polyethylene laminate release paper (Sepack (registered trademark), manufactured by Oji Tac Co., Ltd.) so that the coating amount after drying was 17 g / m ² . (Made by Toyo Came Co., Ltd.) was applied and dried. As a result, a transfer body, which is a laminate of the release paper and the adhesive layer 12, was formed.

Then, the packaging material and the transfer body were bonded together with a press roll so that the paper base material 13 of the packaging material and the adhesive layer 12 of the transfer body faced each other, whereby the packaging material of Example 1 was provided. A wrapping material for sticking was formed.

[Example 2]
Next, the packaging material of Example 2 will be described below.
The paper base material 13 of Example 1 was changed to high-quality paper having a basis weight of 55 g / m ² , and the other configurations were the same as those of Example 1, and the packaging material of Example 2 and the wrapping for sticking were applied. The material was formed.

[Example 3]
Next, the packaging material of Example 3 will be described below.
As the pore-containing film 11A, a biaxially stretched polypropylene resin film (product name: STS50, manufactured by Yupo Corporation) having particles contained therein on the surface and inside was used. A dry laminating adhesive (AD (registered trademark) 900, manufactured by Toyo Morton Co., Ltd.) is applied to one side of the biaxially stretched polypropylene resin film so that the coating amount after drying is 18 g / m ^2. , The intermediate layer 11B of Example 3 was formed.

Next, high-quality paper having a basis weight of 40 g / m ² is laminated on the coated surface made of the dry laminating adhesive to obtain the paper base material 13, and the biaxially stretched polypropylene film and the paper base material 13 Formed the packaging material of Example 3 sandwiching the dry laminating adhesive. Then, the packaging material and the transfer body are pasted with a press roll so that the paper base material 13 of the packaging material in Example 3 and the adhesive layer 12 of the same transfer body as the transfer body used in Example 1 face each other. Together, it formed the patch-on packaging material of Example 3.

[Example 4]
Next, the packaging material of Example 1 will be described below.
A second intermediate layer (thickness: 15 μm) is formed by extruding molten low-density polyethylene (Mirason 11P (registered trademark), manufactured by Mitsui Chemicals, Inc.) from a slit die on the surface of the packaging material of Example 1 on the paper substrate 13 side. A film was formed. Further, the surface of the second intermediate layer was subjected to corona treatment online to obtain the packaging material of Example 4.
Then, the packaging material and the transfer body are bonded together by a press roll so that the second intermediate layer of the packaging material and the adhesive layer 12 of the same transfer body as the transfer body used in Example 1 face each other, thereby. , A sticking-wearing packaging material provided with the packaging material of Example 4 was formed.
[Comparative Example 1]
Next, the packaging material of Comparative Example 1 will be described below.
The paper base material 13 of Example 1 was changed to high-quality paper having a basis weight of 90 g / m ² , and the other configurations were the same as those of Example 1, and the packaging material of Comparative Example 1 and the wrapping for sticking were applied. The material was formed.

[Comparative Example 2]
Next, the packaging material of Comparative Example 1 will be described below.
As the pore-containing film 11A, a biaxially stretched polypropylene resin film (product name: SGS60, manufactured by Yupo Corporation) having particles inside and on the surface was used, and other configurations were compared in the same manner as in Example 1. The packaging material of Example 2 and the pasting and wearing packaging material were formed. The pore-containing film 11A of Comparative Example 2 has a tensile strength larger than that of the pore-containing film 11A of each example, and has a tear strength larger than that of the pore-containing film 11A of each example.

[Comparative Example 3]
Next, the packaging material of Comparative Example 1 will be described below.
As the pore-containing film 11A, a biaxially stretched polypropylene resin film (product name: P2161-20, manufactured by Toyobo Co., Ltd.) having particles contained therein on the surface and inside was used, and other configurations were the same as in Example 1. The wrapping material of Comparative Example 2 and the wrapping material for sticking were formed. The pore-containing film 11A of Comparative Example 2 also has a higher tensile strength than the pore-containing film 11A of each example, and also has a higher tear strength than the pore-containing film 11A of each example.

[Comparative Example 4]
As the packaging material of Comparative Example 4, a biaxially stretched polypropylene resin film (product name: STS50, manufactured by Yupo Corporation) having particles inside and on the surface was used. Then, the biaxially stretched polypropylene resin film and the transfer body are bonded to each other with a press roll so that the packaging material of Comparative Example 4 and the adhesive layer of the transfer body in Example 1 face each other, whereby Comparative Example The pasting and wearing packaging material of 4 was formed.

[Evaluation]
Physical property value evaluation and hand-cutting aptitude evaluation were performed for each of Examples 1 to 3 and Comparative Examples 1 to 4 described above. The physical property values evaluated in the physical property value evaluation are the tensile strength of the paper base material, the tensile strength of the pore-containing film, the tear strength of the pore-containing film, the elongation rate of the pore-containing film, and the packaging material based on the following conditions. The tear strength of the packaging material and the elongation rate of the packaging material. In the following, the orientation direction of the fibers on the paper substrate is the orientation direction Df, and the direction orthogonal to the orientation direction Df is the orthogonal direction Dv.

[Tensile strength]
Rectangular test pieces were collected from the above Examples 1 to 3 and Comparative Examples 1 to 4, and the tensile strength was measured by a method according to JIS P8113: 2006. In addition, the elongation rate was calculated as the ratio of the length of the test piece when it was broken to the length of the test piece before the tensile load was applied. Table 1 shows the tensile strength of the paper base material, the tensile strength of the pore-containing film, and the elongation rate of the pore-containing film of Examples 1 to 3 and Comparative Examples 1 to 4. Table 2 shows the elongation rate of the packaging material.
Specimen length: 150 mm
Distance between chucks: 100 mm
Specimen width: 15 mm
Measuring equipment: Autograph (manufactured by Shimadzu Corporation)
Measurement direction: Orientation direction Df and orthogonal direction Dv

[Tear test]
The tear strength of the biaxially stretched resin film is usually smaller than the tear strength of the paper base material 13. Therefore, it is almost impossible to measure the tear strength of a biaxially stretched resin film by the Ermendorf type tear tester method of JIS P8116: 2000 used for testing the tear strength of a paper substrate 13. On the other hand, the excessively high tear strength of the biaxially stretched resin film is a major obstacle to improving the hand-cutting property of the packaging material even if the pore-containing film 11A satisfies [Condition 1]. ..

Therefore, rectangular test pieces were collected from the above Examples 1 to 3 and Comparative Examples 1 to 4, and JIS P8116: 2000 was used as the tear strength of the pore-containing film and the tear strength of the packaging material. The tear strength when no cut was made was measured by the Ermendorf type tear tester method. Table 1 shows the tear strength of the pore-containing films of Examples 1 to 3 and Comparative Examples 1 to 4, and Table 2 shows the tear strength of the packaging material.
Specimen length: 63 mm
Specimen width: 50 mm
Specimen fixed length: 5 mm
Measuring equipment: Elemendorff tear tester (manufactured by Tozai Seiki Co., Ltd.)
Measurement direction: Orientation direction Df and orthogonal direction Dv

[Hand-cut evaluation]
Whether or not it is possible to collect rectangular test pieces from the above Examples 1 to 3 and Comparative Examples 1 to 4 and tear the test pieces by hand is determined by the orientation direction Df and the orthogonal direction Dv. Was evaluated separately. Table 2 shows the results of the hand-cut evaluation of the packaging material. The test pieces that could be easily torn by hand in both the orientation direction Df and the orthogonal direction Dv are marked with “◯”. Further, for at least one of the orientation direction Df and the orthogonal direction Dv, the one that can be torn by hand but the tear length does not reach the total length of the test piece, the one that can be torn by hand but the test piece can be torn, and the one that can be torn by hand Those that could not be done, these test pieces were marked with an "x".
Specimen length: 50 mm
Specimen width: 50 mm
[Reworkability evaluation]
Test pieces of 50 mm × 50 mm were collected from Examples 1 to 3 and Comparative Examples 1 to 4 above, and an adhesive layer of each test piece was attached to a commercially available PET film having a thickness of 100 μm. A load of 2 kg is applied in one round trip to crimp them. The adhesive layer of each test piece and the PET film were peeled off by hand after 10 minutes, and the state of each test piece was visually confirmed. In Table 2, test pieces that are found to be peeled off cleanly even when peeled off at a very high speed and have excellent reworkability are indicated by “◎” marks. In addition, the test pieces that are found to be peeled off cleanly when peeled off at a normal speed and have no problem in practical use are indicated by "○". In addition, the test piece that did not peel off cleanly and the test piece remained on the PET film and was found to have a problem in practical use is indicated by an “x” mark.

As shown in Table 1, in Examples 1 to 4 and Comparative Examples 2 and 3, it was confirmed that the tensile strength of the paper substrate was 15 N / 10 mm or more and 60 N / 10 mm or less. On the other hand, in the paper base material of Comparative Example 1, a high tensile strength of 72 N / 10 mm was observed.

In Examples 1 to 4 and Comparative Examples 1, 3 and 4, it was confirmed that the tensile strength of the pore-containing film 11A satisfied [Condition 1]. On the other hand, in the pore-containing film 11A of Comparative Example 2, a tensile strength larger than other levels was observed in both the orientation direction Df and the orthogonal direction Dv, and in particular, the orthogonal direction Dv does not satisfy [Condition 1]. A tensile strength of 98 N / 10 mm was observed.

In Examples 1 to 4 and Comparative Examples 1 and 4, it was confirmed that the tear strength of the pore-containing film 11A satisfied [Condition 2] to [Condition 4]. On the other hand, in the pore-containing film 11A of Comparative Examples 2 and 3, a tear strength larger than that of other levels was observed, and in particular, in both directions of Comparative Example 2 and the orthogonal direction Dv of Comparative Example 3, [Condition 2]. A tear strength of more than 100 mN / 10 mm was observed, which did not satisfy the above requirements.

In any of Examples 1 to 4 and Comparative Examples 1 to 4, it was found that the elongation rate of the pore-containing film 11A was larger in the orientation direction Df than in the orthogonal direction Dv. Of all the levels, Examples 1 to 4 and Comparative Examples 1, 2 and 4 were found to have a smaller elongation rate than Comparative Example 3.

As shown in Table 2, the tear strength of the packaging materials of Examples 1 to 4 was found to be smaller than that of any of the comparative examples in both the orientation direction Df and the orthogonal direction Dv, and [Condition 1]. It was confirmed that good hand-cutting property can be obtained by satisfying [Condition 4].

On the other hand, the packaging materials of Comparative Examples 1 and 2 have an elongation rate similar to that of Examples 1 to 4, but have a tear strength higher than that of Examples 1 to 4, and as a result, good hand-cutting property is obtained. It was found that it could not be obtained. Further, the packaging material of Comparative Example 3 has a elongation rate larger than that of Examples 1 to 4 and a tear strength larger than that of Examples 1 to 4 in the orientation direction Df, and as a result, a good hand is obtained. It was found that the cutability could not be obtained. Further, the packaging material of Comparative Example 4 has a tear strength smaller than that of Examples 1 to 4, but has a much larger elongation rate than that of Examples 1 to 4, and as a result, good hand-cutting property is obtained. It was found that it could not be obtained.
In all of Examples 1 to 4 and Comparative Examples 1 to 4, reworkability without any problem in practical use was observed. In particular, with respect to Example 4 and Comparative Example 4, it was confirmed that the PET film was peeled off cleanly even when peeled off at a very high speed, and the reworkability was very excellent.

As described above, according to the above embodiment, the effects described below can be obtained.
(1) Since the pores 11H are present on the surface and the inside of the pore-containing film 11A, it is possible to improve the hand-cutting property of the packaging material.

(2) The tensile strength of the paper base material 13 is 15 N / 10 mm or more and 60 N / 10 mm or less in the orientation direction of the paper base material 13. The tensile strength of the pore-containing film 11A is also 15 N / 10 mm or more and 60 N / 10 mm or less, like the paper base material 13. Therefore, it is possible to suppress a decrease in hand-cutting property due to the tendency of the pore-containing film 11A to stretch.

(3) The tear strength when no cut is made by the Elmendorf type tear tester method of JIS P8116: 2000 is 100 mN / mm or less in the pore-containing film 11A. That is, since both [Condition 1] regarding the tensile strength and [Condition 2] regarding the tear strength are satisfied, it is possible to more reliably improve the hand-cutting property.

(4) When the ratio of the maximum value to the minimum value of the tear strength in the in-plane direction of the pore-containing film 11A is 1.0 or more and 1.2 or less, the tear strength of the pore-containing film 11A varies. Is suppressed. That is, if the configuration satisfies the above [Condition 3], it is possible to suppress variations in hand-cutting property due to variations in tear strength of the pore-containing film 11A. As a result, when using the packaging material, it is possible to reduce the restriction of separately presenting the user in the direction in which the hand-cutting property can be obtained.

(5) In the in-plane direction of the pore-containing film 11A, the direction showing the maximum value of the tear strength is the orientation direction in the paper base material 13, and the direction showing the minimum value in the tear direction is the paper base material 13. Is the direction orthogonal to the orientation direction of. That is, if the configuration satisfies [Condition 4] and [Condition 5], the direction showing the minimum value of the tear strength of the pore-containing film 11A and the direction showing a relatively large tear strength in the paper substrate 13. Therefore, it is possible to improve the uniformity of the tear strength in the entire packaging material. This also makes it possible to reduce the restriction that the user is separately presented with the direction in which the hand-cutting property can be obtained when the packaging material is used.

(6) The pore-containing film 11A has a tensile strength of 15 N / 10 mm or more and 30 N / 10 mm or less in the orientation direction according to JIS P8113: 2006, and conforms to JIS P8113: 2006 in the direction orthogonal to the orientation direction. The tensile strength is 40 N / 10 mm or more and 60 N / 10 mm or less. The tensile strength of the paper base material 13 in the orientation direction is usually larger than the tensile strength in the direction orthogonal to the orientation direction. In this respect, according to the above configuration, the direction showing a relatively small tensile strength in the pore-containing film 11A and the direction showing a relatively large tensile strength in the paper substrate 13 coincide with each other. It is also possible to increase the uniformity of tensile strength in the entire packaging material. This also makes it possible to reduce the restriction that the user is separately presented with the direction in which the hand-cutting property can be obtained when the packaging material is used.

(7) Compared with the case where the packaging material is composed of only the paper base material 13, since the pore-containing film 11A is further provided, the dependence of the paper base material 13 on the strength required for the packaging material can be suppressed. Since the packaging material separately provides the strength of the pore-containing film 11A, even if the paper base material 13 absorbs water, the decrease in strength of the packaging material can be suppressed. As a result, it is suitable as a packaging material for multi-packs that bundles individual packages of refrigerated products and individual packages of frozen products.

(8) If the basis weight of the paper base material 13 is 85 g / m ² or less, it may be difficult to obtain hand-cutting property due to the excessively large basis weight of the paper base material 13. It can be suppressed.

(9) The pore-containing film 11A has pores 11H on the surface and inside. Since the pore-containing film 11A constitutes the surface of the packaging material, it is possible to enhance the acceptability of inorganic pigments and organic pigments on the surface of the packaging material. Therefore, it is possible to improve the printability of the packaging material.

The above embodiment can also be modified and implemented as follows.
-The pore-containing film 11A may be subjected to various surface treatments such as corona treatment, plasma treatment, and chromic acid treatment on the surface of the pore-containing film 11A for the purpose of improving printability. It is possible. It is also possible to omit these various surface treatments when sufficient printability is obtained due to the effect according to (9) above.

11 ... Resin film, 11A ... Pore-containing film, 11B ... Intermediate layer, 11H ... Pore, 11P ... Particles, 12 ... Adhesive layer, 13 ... Paper substrate.

Claims (5)

Paper substrate and
A biaxially stretched resin film adhered to the paper substrate and
It is a packaging material equipped with
The paper base material is
The tensile strength of the fiber in the orientation direction according to JIS P8113: 2006 is 15 N / 10 mm or more and 60 N / 10 mm or less.
The biaxially stretched resin film is
It has holes on the surface and inside, and the tensile strength according to JIS P8113: 2006 is 15N / 10mm or more and 60N / 10mm or less, and
A packaging material having a tear strength of 100 mN / mm or less when no cut is made by the Elmendorf type tear tester method of JIS P8116: 2000. Among the in-plane directions of the biaxially stretched resin film, the ratio of the maximum value of the tear strength to the minimum value of the tear strength is 1.0 or more in two directions orthogonal to each other including the orientation direction. 2. The packaging material according to claim 1, which is 2 or less. The maximum value is the tear strength in the orientation direction.
The packaging material according to claim 2, wherein the minimum value is the tear strength in a direction orthogonal to the orientation direction. The biaxially stretched resin film is
The tensile strength according to JIS P8113: 2006 in the orientation direction is 15 N / 10 mm or more and 30 N / 10 mm or less.
The packaging material according to any one of claims 1 to 3, wherein the tensile strength according to JIS P8113: 2006 in the direction orthogonal to the orientation direction is 40 N / 10 mm or more and 60 N / 10 mm or less. The packaging material according to any one of claims 1 to 4, wherein the basis weight of the paper base material is 85 g / m ² or less.

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