JP2023173134A - Laminate and packaging bag - Google Patents

Abstract

To provide a laminate that has high recycling suitability and has an increased ability to be cut in a plurality of directions, and a packaging bag that is made from the laminate.SOLUTION: A laminate includes a substrate layer including biaxially stretched polypropylene, a vapor deposition layer at least one of metal and inorganic oxide, and a sealant layer including polypropylene. In the laminate, the total mass of the biaxially stretched polypropylene and the polypropylene is 90 mass% or more. The thickness of the substrate layer constitutes 45% or more of the total thickness of the laminate.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a laminate and a packaging bag.

A laminate is known that includes a biaxially oriented PET (polyethylene terephthalate) film with excellent heat resistance and toughness as a base film, and a polyolefin film such as polyethylene or polypropylene as a sealant layer (see, for example, Patent Document 1). .

Japanese Patent Application Publication No. 2017-178357

As the plastic waste issue draws attention around the world, demand for environmentally friendly packaging materials is increasing to help realize a recycling-oriented society. Regarding packaging materials, many global companies have set goals and are implementing various measures for better plastic resource circulation. Furthermore, in the United States, recycling routes for PE (polyethylene) from recovery to reuse are beginning to be established, and recycling efforts based on monomaterials (single material) are accelerating worldwide. That is, even in packaging laminates, which have conventionally achieved higher performance by combining various different materials, there is a growing demand for monomaterials. For example, a laminate in which the mass ratio of a single resin material in the laminate is 90% by mass or more can be said to be a monomaterial laminate (a laminate mainly composed of a single resin material).

From the viewpoint of recycling suitability, the use of laminates mainly composed of polyolefins is being considered. A packaging bag using such a laminate may be made easier to open by, for example, half-cutting, perforation, laser processing, or the like. However, half-cut processing and perforation processing may deteriorate the gas barrier properties of the laminate. Furthermore, since polyolefin is difficult to absorb laser (particularly CO ₂ laser), there is a problem in the suitability of laser processing of packaging bags using the above-mentioned laminate. For this reason, a laminate mainly composed of polyolefin is required to have an aspect that can improve cuttability while maintaining gas barrier properties.

An object of one aspect of the present disclosure is to provide a laminate that has high recyclability and can improve cuttability in multiple directions while maintaining gas barrier properties, and a packaging bag made from the laminate.

A laminate according to one aspect of the present disclosure includes a base layer containing biaxially oriented polypropylene, a vapor deposition layer containing at least one of a metal and an inorganic oxide, and a sealant layer containing polypropylene. The ratio of the total mass of the axially oriented polypropylene and polypropylene is 90% by mass or more, and the ratio of the thickness of the base material layer to the thickness of the laminate is 45% or more.

According to the above-mentioned laminate, since the ratio of the total mass of biaxially oriented polypropylene and polypropylene in the laminate is 90% by mass or more, the laminate can be highly recyclable. In addition, the ratio of the thickness of the base material layer containing biaxially oriented polypropylene to the thickness of the laminate is 45% or more. Thereby, the cuttability of the laminate can be improved without performing processing to impart ease of opening to the laminate. Therefore, damage to the deposited layer due to the processing does not occur, so that the cuttability of the laminate in multiple directions can be improved while maintaining the gas barrier properties of the laminate.

The laminate further includes an anchor coat layer located between the base material layer and the vapor deposition layer, the anchor coat layer contains a resin having a polar group, and the base material layer and the anchor coat layer are coextruded layers. But that's fine. In this case, the presence of the anchor coat layer makes it difficult for the vapor deposited layer to peel off, so deterioration of the gas barrier properties of the laminate due to the peeling is less likely to occur. In addition, since the anchor coat layer contains a resin having a polar group, the resin is likely to crystallize. When such an anchor coat layer and a base material layer are coextruded layers, the cuttability of the laminate is less likely to be inhibited by the anchor coat layer.

A laminate according to another aspect of the present disclosure includes a base layer containing biaxially oriented polypropylene, a resin layer containing biaxially oriented polypropylene, and a laminate located on the resin layer and containing at least one of a metal and an inorganic oxide. an intermediate layer having a vapor-deposited layer containing polypropylene, and a sealant layer containing polypropylene, wherein the proportion of the total mass of biaxially oriented polypropylene and polypropylene in the laminate is 90% by mass or more, and The ratio of the total thickness of the material layer and the resin layer is 45% or more.

According to the above-mentioned laminate, since the ratio of the total mass of biaxially oriented polypropylene and polypropylene in the laminate is 90% by mass or more, the laminate can be highly recyclable. In addition, the ratio of the total thickness of the base layer containing biaxially oriented polypropylene and the resin layer to the thickness of the laminate is 45% or more. Thereby, the cuttability of the laminate can be improved without performing processing to impart ease of opening to the laminate. Therefore, damage to the deposited layer due to the processing does not occur, so that the cuttability of the laminate in multiple directions can be improved while maintaining the gas barrier properties of the laminate.

The intermediate layer further includes an anchor coat layer located between the resin layer and the vapor deposition layer, the anchor coat layer contains a resin having a polar group, and the resin layer and the anchor coat layer may be coextruded layers. In this case, the presence of the anchor coat layer makes it difficult for the vapor deposited layer to peel off, so deterioration of the gas barrier properties of the laminate due to the peeling is less likely to occur. In addition, since the anchor coat layer contains a resin having a polar group, the resin is likely to crystallize. Since such an anchor coat layer and a resin layer are coextruded layers, the cuttability of the laminate is less likely to be inhibited by the anchor coat layer.

The adhesive layer may further include an adhesive layer located between the base material layer and the sealant layer and containing a urethane resin. In this case, while maintaining cuttability, peeling between the base material layer and the sealant layer becomes less likely to occur.

The tear strength in the width direction of the laminate measured according to the trousers tear method described in JIS K 7128-1:1998 may be 5.0 N or less.

The tear strength of the laminate in the machine direction measured according to the trousers tear method described in JIS K 7128-1:1998 may be 5.0 N or less.

The packaging bag according to one aspect of the present disclosure may be a bag made of a laminate. Further, the packaging bag may be a pillow packaging bag. In these cases, the packaging bag can be easily torn in multiple directions.

According to one aspect of the present disclosure, it is possible to provide a laminate that has high recyclability and can improve cuttability in multiple directions while maintaining gas barrier properties, and a packaging bag made from the laminate.

FIG. 1(a) is a schematic plan view of a laminate according to one embodiment, and FIG. 1(b) is a schematic cross-sectional view showing the laminate according to one embodiment. FIG. 2 is a schematic front view of an example of a packaging bag. FIG. 3(a) is a schematic front view showing another example of the packaging bag, and FIG. 3(b) is a sectional view taken along line IIIb-IIIb in FIG. 3(a). FIG. 4 is a schematic cross-sectional view showing a laminate according to a first modification. FIG. 5 is a schematic cross-sectional view showing a laminate according to a second modification. FIG. 6(a) is a schematic plan view showing the sample, and FIG. 6(b) is a schematic plan view showing the sample after the trousers tear test.

Hereinafter, preferred embodiments of the present disclosure will be described in detail, with reference to the drawings as the case may be. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant explanations will be omitted. Furthermore, the dimensional ratios in the drawings are not limited to the ratios shown.

<Laminated body>
FIG. 1(a) is a schematic plan view of a laminate according to one embodiment, and FIG. 1(b) is a schematic cross-sectional view showing the laminate according to one embodiment. A laminate 1 shown in FIGS. 1(a) and 1(b) is a sheet-like packaging material used for manufacturing packaging bags, for example, and includes a base material 10, a sealant layer 20, and an adhesive layer 30. . The base material 10 and the sealant layer 20 are bonded together with an adhesive layer 30. In the laminate 1, a base material 10, an adhesive layer 30, and a sealant layer 20 are laminated in this order. In this embodiment, the base material 10, the adhesive layer 30, and the sealant layer 20 each contain polypropylene. Hereinafter, the direction MD shown in FIG. 1(a) will be taken as the flow direction (longitudinal direction) of the laminate 1, and the direction TD will be taken as the width direction (short direction) of the laminate 1. Further, a direction perpendicular to both the directions MD and TD is defined as the lamination direction of the members included in the laminate 1.

In one embodiment, the laminate 1 is a member realized as a monomaterial. In this specification, when a laminate is formed from substantially a single material (monomaterial), it can be considered that the laminate has been made into a monomaterial. When the mass ratio of a specific material contained in a laminate is 90% by mass or more, the laminate is considered to be substantially formed from a single material (monomaterial). In this embodiment, the proportion of the total mass of polypropylene in the laminate 1 is 90% by mass or more. From the viewpoint of achieving a higher degree of monomaterialization of the laminate 1, the mass ratio of polypropylene contained in the laminate 1 may be 92.5% by mass or more, or 95% by mass or more.

<Base material 10>
The base material 10 is a layered member that functions as a support in the laminate 1 and includes a base material layer 11, an anchor coat layer 12, and a vapor deposition layer 13. In the base material 10, a base material layer 11, an anchor coat layer 12, and a vapor deposition layer 13 are laminated in this order. Therefore, the anchor coat layer 12 is located between the base material layer 11 and the vapor deposition layer 13. The proportion of the total mass of polypropylene in the base material 10 is 90% by mass or more. Therefore, the base material 10 can be said to be a member that has been realized as a monomaterial.

Base material layer 11 contains polypropylene. The base layer 11 may contain or be made of a polypropylene film. The polypropylene film may be an acid-modified polypropylene film obtained by graft-modifying polypropylene using an unsaturated carboxylic acid, an acid anhydride of an unsaturated carboxylic acid, an ester of an unsaturated carboxylic acid, or the like. Further, as the polypropylene, polypropylene resins such as homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, propylene-α-olefin copolymer, etc. can be used.

Various additives such as a flame retardant, a slip agent, an anti-blocking agent, an antioxidant, a light stabilizer, a tackifier, and an antistatic agent may be added to the polypropylene film constituting the base layer 11.

The polypropylene film constituting the base layer 11 is a biaxially stretched film that is stretched in the direction MD and the direction TD. Therefore, the base material layer 11 includes biaxially oriented polypropylene (OPP), which is a type of polypropylene. In this case, the laminate 1 can be easily cut along the direction MD and the laminate 1 can be easily cut along the direction TD. In addition, it is possible to prevent the base material layer 11 from being thermally fused in the heat sealing process during bag manufacturing. Furthermore, the laminate 1 and packaging bags formed from the laminate 1 can be suitably used in applications where retort processing and boiling processing are performed.

From the viewpoint of cuttability of the laminate 1, the thickness ratio of the base layer 11 (OPP thickness ratio) is 45% or more of the thickness of the laminate 1. The ratio may be 48% or more, or 50% or more. The thickness of the base material layer 11 is, for example, 10 μm or more and 200 μm or less, from the viewpoint of material reduction to reduce environmental load, and from the viewpoint of obtaining excellent heat resistance, impact resistance, and excellent gas barrier properties. The thickness of the material layer 11 may be, for example, 20 μm or more, 25 μm or more, 30 μm or more, 40 μm or more, 100 μm or less, 60 μm or less, or 50 μm or less. Alternatively, the mass ratio (OPP mass ratio) of the base material layer 11 in the laminate 1 may be 45% by mass or more, 48% by mass or more, or 50% by mass or more.

The laminated surface of the base material layer 11 may be subjected to various pretreatments such as corona treatment, plasma treatment, flame treatment, etc., or may be provided with a coating layer such as an easy-adhesion layer, as long as the barrier performance is not impaired.

Anchor coat layer 12 is a portion having a surface on which vapor deposition layer 13 is provided. By providing the anchor coat layer 12, two effects can be obtained: improved adhesion between the base layer 11 and the vapor deposited layer 13, and improved smoothness of the surface of the base layer 11. In addition, by improving the smoothness, it becomes easier to form the vapor deposition layer 13 uniformly without defects, and it becomes easier to exhibit high barrier properties. Anchor coat layer 12 can be formed using, for example, an anchor coat agent.

Examples of the anchor coating agent include polyester polyurethane resins, polyether polyurethane resins, and the like. As the anchor coating agent, polyester-based polyurethane resin is preferable from the viewpoint of heat resistance and interlayer adhesive strength. From the viewpoint of cuttability of the anchor coat layer 12, etc., the resin contained in the anchor coat agent may be a resin having a polar group.

Although the thickness of the anchor coat layer 12 is not particularly limited, it is significantly smaller than that of the base layer 11. The thickness of the anchor coat layer 12 is, for example, preferably in the range of 0.01 to 5 μm, more preferably in the range of 0.03 to 3 μm, particularly preferably in the range of 0.05 to 2 μm. preferable. When the thickness of the anchor coat layer 12 is at least the above lower limit, more sufficient interlayer adhesive strength tends to be obtained. On the other hand, when the thickness of the anchor coat layer 12 is less than or equal to the above upper limit, desired gas barrier properties tend to be easily exhibited.

As a method for coating the anchor coat layer 12 on the base material layer 11, any known coating method can be used without particular limitation, such as a dipping method; a spray, a coater, a printing machine, a brush, etc. There are several methods. In addition, the types of coaters and printing machines used in these methods and their coating methods include gravure coaters such as direct gravure method, reverse gravure method, kiss reverse gravure method, and offset gravure method, reverse roll coater, and microgravure. Examples include a coater, a chamber doctor coater, an air knife coater, a dip coater, a bar coater, a comma coater, and a die coater.

The coating amount of the anchor coat layer 12 is preferably 0.01 to 5 g/m ² , and preferably 0.03 to 3 g/m ² in mass per 1 m ² after coating and drying the anchor coating agent. It is more preferable that When the mass per 1 m ² after coating and drying the anchor coating agent is above the above lower limit, film formation tends to be sufficient, while when it is below the above upper limit, it is sufficiently easy to dry and the solvent is removed. It tends to be difficult to remain.

Methods for drying the anchor coat layer 12 are not particularly limited, but include natural drying, drying in an oven set at a predetermined temperature, and a dryer attached to the coater, such as an arch dryer, a floating dryer, and a drum dryer. , a method using an infrared dryer, etc. Further, the drying conditions can be appropriately selected depending on the drying method. For example, in the case of drying in an oven, it is preferable to dry at a temperature of 60 to 100° C. for about 1 second to 2 minutes.

As the anchor coat layer 12, a polyvinyl alcohol resin can be used instead of the polyurethane resin described above. The polyvinyl alcohol resin may be any resin having a vinyl alcohol unit formed by saponifying a vinyl ester unit, and examples thereof include polyvinyl alcohol (PVA) and ethylene-vinyl alcohol copolymer (EVOH).

As PVA, for example, vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, and vinyl versatate can be polymerized alone. , followed by saponified resins. The PVA may be a copolymerized or post-modified modified PVA. Modified PVA can be obtained, for example, by copolymerizing a vinyl ester and an unsaturated monomer copolymerizable with the vinyl ester, followed by saponification. Examples of unsaturated monomers copolymerizable with vinyl ester include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, and α-octadecene; 3-buten-1-ol, 4-pentyn-1-ol , 5-hexen-1-ol, etc.; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, undecylenic acid; acrylonitrile, methacrylonitrile, etc. Nitriles; amides such as diacetone acrylamide, acrylamide, and methacrylamide; olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid, and methallyl sulfonic acid; alkyl vinyl ethers, dimethylallyl vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinyl ethylene Vinyl compounds such as carbonate, 2,2-dialkyl-4-vinyl-1,3-dioquinrane, glycerin monoallyl ether, 3,4-diacetoxy-1-butene; vinylidene chloride, 1,4-diacetoxy-2-butene, Examples include vinylene carbonate.

The degree of polymerization of PVA is preferably 300 to 3,000. If the degree of polymerization is less than 300, the barrier properties tend to deteriorate, and if it exceeds 3000, the viscosity is too high and the coating suitability tends to deteriorate. The degree of saponification of PVA is preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 99 mol% or more. Moreover, the degree of saponification of PVA may be 100 mol% or less, or 99.9 mol% or less. The degree of polymerization and saponification of PVA can be measured according to the method described in JIS K 6726 (1994).

EVOH is generally a copolymer of ethylene and acid vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, and vinyl versatate. Obtained by saponifying the union.

The degree of polymerization of EVOH is preferably 300 to 3,000. If the degree of polymerization is less than 300, the barrier properties tend to deteriorate, and if it exceeds 3000, the viscosity is too high and the coating suitability tends to deteriorate. The degree of saponification of the vinyl ester component of EVOH is preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 99 mol% or more. Further, the degree of saponification of EVOH may be 100 mol% or less, or 99.9 mol% or less. The degree of saponification of EVOH is determined by nuclear magnetic resonance (1H-NMR) measurement from the peak area of hydrogen atoms contained in the vinyl ester structure and the peak area of hydrogen atoms contained in the vinyl alcohol structure.

The ethylene unit content of EVOH is 10 mol% or more, more preferably 15 mol% or more, even more preferably 20 mol% or more, and particularly preferably 25 mol% or more. Further, the ethylene unit content of EVOH is preferably 65 mol% or less, more preferably 55 mol% or less, and even more preferably 50 mol% or less. When the ethylene unit content is 10 mol % or more, gas barrier properties or dimensional stability under high humidity can be maintained favorably. On the other hand, when the ethylene unit content is 65 mol% or less, gas barrier properties can be improved. The ethylene unit content of EVOH can be determined by NMR method.

When a polyvinyl alcohol resin is used as the anchor coat layer 12, methods for forming the anchor coat layer 12 include coating using a polyvinyl alcohol resin solution, multilayer extrusion, and the like. In this embodiment, the base material layer 11 and the anchor coat layer 12 are coextruded layers.

The vapor deposition layer 13 is a layer exhibiting gas barrier properties against water vapor and oxygen, and contains at least one of a metal and an inorganic oxide. The vapor deposition layer 13 may have a single layer structure or a laminated structure. For this reason, the vapor deposition layer 13 includes at least one of a metal vapor deposition layer and an inorganic oxide layer. When the vapor deposition layer 13 includes a metal vapor deposition layer, examples of the metal contained in the metal vapor deposition layer include aluminum, stainless steel, and the like. When the vapor deposition layer 13 includes an inorganic oxide layer, examples of the inorganic oxide contained in the inorganic oxide layer include aluminum oxide, silicon oxide, magnesium oxide, and tin oxide. From the viewpoint of transparency and barrier properties, the inorganic oxide may be selected from the group consisting of aluminum oxide, silicon oxide, and magnesium oxide. Further, from the viewpoint of excellent tensile stretchability during processing, it is preferable that the inorganic oxide layer is a layer using silicon oxide. By using an inorganic oxide layer, high barrier properties can be obtained with a very thin layer that does not affect the recyclability of the vapor deposited layer 13.

The thickness of the vapor deposited layer 13 is preferably 10 nm or more and 50 nm or less. When the thickness of the vapor deposited layer 13 is 10 nm or more, sufficient water vapor barrier properties can be obtained. Moreover, when the thickness of the vapor deposited layer 13 is 50 nm or less, generation of cracks due to deformation due to internal stress of the vapor deposited layer 13 can be suppressed, and deterioration of water vapor barrier properties can be suppressed. It should be noted that if the thickness of the vapor deposited layer 13 exceeds 50 nm, the cost tends to increase due to an increase in the amount of material used, a longer film formation time, etc., which is not preferable from an economical point of view. From the same viewpoint as above, the thickness of the vapor deposition layer 13 is more preferably 20 nm or more and 40 nm or less.

The vapor deposition layer 13 can be formed, for example, by vacuum film formation. In vacuum film formation, a physical vapor deposition method or a chemical vapor deposition method can be used. Examples of the physical vapor deposition method include, but are not limited to, a vacuum evaporation method, a sputtering method, an ion plating method, and the like. Examples of the chemical vapor deposition method include, but are not limited to, a thermal CVD method, a plasma CVD method, a photo CVD method, and the like.

The above vacuum film formation methods include resistance heating vacuum evaporation, EB (Electron Beam) heating vacuum evaporation, induction heating vacuum evaporation, sputtering, reactive sputtering, dual magnetron sputtering, and plasma chemical vapor deposition. (PECVD method) etc. are particularly preferably used. However, in terms of productivity, the vacuum deposition method is currently the best. As a heating means for the vacuum evaporation method, it is preferable to use one of an electron beam heating method, a resistance heating method, and an induction heating method.

<Sealant layer 20>
The sealant layer 20 is a layer that provides sealing properties by heat sealing or the like in the laminate 1, and contains polypropylene. Sealant layer 20 may include or consist of a polypropylene film. The polypropylene film constituting the sealant layer 20 is preferably a non-stretched film from the viewpoint of improving sealing performance by heat sealing. For this reason, the sealant layer 20 includes unstretched polypropylene (CPP). Various additives such as a flame retardant, a slip agent, an anti-blocking agent, an antioxidant, a light stabilizer, a tackifier, and an antistatic agent may be added to the polypropylene film constituting the sealant layer 20.

The thickness of the sealant layer 20 is determined by the use of the laminate 1, the thickness of the base layer 11, and the like. The thickness of the sealant layer 20 is, for example, 20 μm or more and 100 μm or less. The thickness of the sealant layer 20 may be 25 μm or more, 30 μm or more, 40 μm or more, 80 μm or less, 60 μm or less, or 50 μm or less.

<Adhesive layer 30>
In the laminate 1, a base material 10 and a sealant layer 20 are laminated with an adhesive layer 30 interposed therebetween. The adhesive layer 30 includes an adhesive such as a dry laminating adhesive, a non-solvent laminating adhesive, or a barrier adhesive. The adhesive may include, for example, polyester-isocyanate resin, urethane resin, polyether resin, and the like. From the viewpoint of cuttability, heat resistance, etc. of the laminate 1, the adhesive layer 30 may contain urethane resin. The adhesive layer 30 does not need to contain chlorine. In this case, it is possible to suppress the adhesive forming the adhesive layer 30, the coloring of the recycled resin, etc., and the generation of odor due to heat treatment. From the viewpoint of environmental considerations, the adhesive layer 30 may be formed of a biomass material and may not contain a solvent.

<Tear strength of laminate 1>
In this embodiment, the tear strength of the laminate 1 is measured according to the trousers tear method described in JIS K 7128-1:1998. The tear strength of the laminate 1 in the direction MD and the tear strength of the laminate 1 in the direction TD according to the trousers tear method are each 5.0 N or less. When the tear strength is 5.0 N or less and the OPP thickness ratio is 45% or more of the thickness of the laminate 1, when the laminate 1 is torn in the directions MD and TD, the sealant layer 20 Elongation, peeling (delamination) between the base material 10 and the sealant layer 20, etc. are less likely to occur. Therefore, when tearing the packaging bag that is the bag-made product of the laminate 1, the packaging bag can be easily torn along multiple directions.

The laminate 1 may further include a printed layer. The printing layer may be provided between the base material 10 and the adhesive layer 30, or may be provided on the surface of the base material 10 opposite to the adhesive layer 30. The printed layer does not need to contain chlorine from the viewpoint of suppressing coloring and generation of odor when the printed layer is remelted. The printing layer may be formed from a biomass material from the viewpoint of environmental consideration.

<Packaging bag>
Below, an example of a packaging bag that is a bag-made product of the laminate 1 will be described with reference to FIGS. 2 and 3. FIG. 2 is a schematic plan view of an example of a packaging bag. The packaging bag 100 shown in FIG. 2 is formed into a bag shape by, for example, sealing the ends of the laminate 1 which is folded in two so as to sandwich the contents therebetween.

The packaging bag 100 is a three-sided bag having a main body part 101 in which the contents are stored, a seal part 102 located at the end of the main body part 101, and a bent part 103 where the laminate 1 is bent. The shape of the main body portion 101 is not particularly limited, and has a rectangular shape when viewed from a predetermined direction, for example. At least a portion of the outer surface of the main body portion 101 may be printed. For example, the main body portion 101 may contain a specific gas such as nitrogen in addition to the contents. The seal portion 102 is a portion where a portion of the sealant layer 20 included in the laminate 1 and another portion are bonded together. In the seal portion 102, a portion of the sealant layer 20 included in the laminate 1 and another portion are in close contact with each other. The seal portion 102 is formed, for example, by heating and compressing (that is, heat-sealing) a part of the sealant layer 20 and another part of the laminate 1, but is not limited thereto. For example, the seal portion 102 may be formed by cold sealing or the like. In the packaging bag 100, the bent portion 103 constitutes one side of the main body 101, and the seal portion 102 constitutes the remaining three sides of the main body 101. Both ends of the bent portion 103 and the seal portion 102 overlap.

FIG. 3(a) is a schematic front view showing another example of the packaging bag, and FIG. 3(b) is a sectional view taken along line IIIb-IIIb in FIG. 3(a). The packaging bag 100A shown in FIGS. 3(a) and 3(b) is a pillow packaging bag that is a folded body of the laminate 1. The pillow packaging bag can be formed using, for example, a known pillow packaging and filling machine. In this case, after bending the laminate 1 with the sealant layer 20 (see FIG. 1) located inside using the packaging and filling machine described above, a part of the sealant layer 20 and another part are separated. By adhering, a packaging bag 100A, which is a pillow packaging bag, is formed. The packaging bag 100A includes a main body 110 having a cylindrical shape and a flange portion 111. Hereinafter, the direction perpendicular to the axial direction of the main body 110 will be referred to as the width direction of the main body 110. Before bending the laminate 1, the axial direction corresponds to one of the directions MD and TD of the laminate 1, and the width direction corresponds to the other of the directions MD and TD of the laminate 1. In this embodiment, the axial direction corresponds to the direction MD, and the width direction corresponds to the direction TD.

The main body 110 is formed by rolling the laminate 1 along the width direction. Both ends 112 of the main body 110 in the axial direction are sealed with a sealant layer 20. From the viewpoint of accommodating the contents, the dimension of the main body 110 along the axial direction is, for example, 80% or more of the dimension of the laminate 1 along the axial direction. From the viewpoint of sealability of both ends 112, the dimension of the main body 110 along the axial direction is, for example, 90% or less of the dimension of the laminate 1 along the axial direction.

The flange portion 111 is a portion provided when the packaging bag 100A is formed, and extends along the axial direction and protrudes from the main body 110. The flange portion 111 extends from one end of the packaging bag 100A to the other end in the axial direction. As shown in FIG. 3(b), the flange portion 111 corresponds to a portion where a pair of ends of the sealant layer 20 in the width direction are bonded together when the laminate 1 is expanded. When the laminate 1 is expanded, the dimension of the flange portion 111 along the width direction is, for example, 2% or more and 5% or less of the dimension of the laminate 1 along the width direction. In this case, the flange portion 111 can be bonded together satisfactorily while ensuring the volume of the packaging bag 100A. The pair of ends are bonded together at the same time as both ends 112 of the main body 110 are sealed.

According to the laminate 1 according to the present embodiment described above, the total mass of polypropylene in the laminate 1, specifically the sum of the biaxially oriented polypropylene contained in the base material 10 and the polypropylene contained in the sealant layer 20. Since the mass ratio is 90% by mass or more, the recyclability of the laminate 1 can be increased. In addition, the ratio of the thickness of the base material layer 11 containing biaxially oriented polypropylene to the thickness of the laminate 1 is 45% or more. Thereby, the cuttability of the laminate 1 can be improved without performing processing to impart ease of opening to the laminate 1. Therefore, damage to the vapor deposited layer 13 due to the processing does not occur, so that the cuttability of the laminate 1 in multiple directions can be improved while maintaining the gas barrier properties of the laminate 1. Therefore, for example, the packaging bags 100, 100A, which are bags made of the laminate 1, can be easily torn from multiple directions without perforating them. Therefore, by using the laminate 1, it is possible to manufacture packaging bags 100, 100A that can improve cutability in multiple directions while maintaining sealing performance.

In the present embodiment, the laminate 1 includes an anchor coat layer 12 located between a base layer 11 and a vapor deposition layer 13, and the anchor coat layer 12 contains a resin having a polar group, and the base layer 11 and Anchor coat layer 12 is a coextrusion layer. For this reason, the existence of the anchor coat layer 12 makes it difficult for the vapor deposited layer 13 to peel off, so that deterioration of the gas barrier properties of the laminate 1 due to the peeling becomes difficult to occur. In addition, since the anchor coat layer 12 contains a resin having a polar group, the resin is likely to crystallize. Since the anchor coat layer 12 and the base material layer 11 are coextruded layers, the cuttability of the laminate 1 by the anchor coat layer 12 is less likely to be inhibited.

In this embodiment, the laminate 1 includes an adhesive layer 30 located between the base material layer 11 and the sealant layer 20 and containing a urethane resin. For this reason, peeling between the base layer 11 and the sealant layer 20 is less likely to occur while maintaining cuttability.

Next, a modification of the above embodiment will be described with reference to FIGS. 4 and 5. In the following, descriptions that overlap with the above embodiments will be omitted, and portions that are different from the above embodiments will be described. That is, within the technically possible range, the description of the above embodiment may be appropriately used in the modification.

FIG. 4 is a schematic cross-sectional view showing a laminate according to a first modification. As shown in FIG. 4, the laminate 1A includes a base layer 11, a sealant layer 20, adhesive layers 30A and 30B, and an intermediate layer 40. The base material layer 11 and the intermediate layer 40 are bonded together with an adhesive layer 30A. Further, the sealant layer 20 and the intermediate layer 40 are bonded together with an adhesive layer 30B. In the laminate 1A, the base material layer 11, the adhesive layer 30A, the intermediate layer 40, the adhesive layer 30B, and the sealant layer 20 are laminated in this order. In the first modification, each of the base layer 11, the sealant layer 20, and the intermediate layer 40 contains polypropylene. The mass ratio of polypropylene contained in the laminate 1A may be 90% by mass or more.

By including the intermediate layer 40 in the laminate 1A, deformation during bag making can be further reduced compared to the laminate of the above embodiment. The intermediate layer 40 includes a resin layer 41, an anchor coat layer 42, and a vapor deposition layer 43. In the intermediate layer 40, a resin layer 41, an anchor coat layer 42, and a vapor deposition layer 43 are laminated in this order. Therefore, the anchor coat layer 42 is located between the resin layer 41 and the vapor deposition layer 43. In the stacking direction, the vapor deposition layer 43 of the intermediate layer 40 is closest to the sealant layer 20 . In the first modification, the vapor deposition layer 43 contacts the adhesive layer 30B, and the resin layer 41 contacts the adhesive layer 30A. The proportion of the total mass of polypropylene in the intermediate layer 40 is 90% by mass or more. Therefore, the intermediate layer 40 can be said to be a member that has been realized as a monomaterial.

The resin layer 41 contains polypropylene. The polypropylene film constituting the resin layer 41 is a biaxially stretched film that is stretched in the direction MD and the direction TD, similarly to the base material layer 11. Therefore, the resin layer 41 includes biaxially oriented polypropylene, which is a type of polypropylene. In the first modification, the directions MD and TD of the resin layer 41 and the directions MD and TD of the base material layer 11 correspond to each other. In this case, it is possible to more easily cut the laminate 1A along the direction MD and cut the laminate 1A along the direction TD. The anchor coat layer 42 is a layer that exhibits the same function as the anchor coat layer 12 of the first embodiment, and is a portion having a surface on which a vapor deposition layer 43 is provided. The vapor deposition layer 43 is a layer that exhibits the same function as the vapor deposition layer 13 of the first embodiment, is a layer that exhibits gas barrier properties against water vapor and oxygen, and contains at least one of a metal and an inorganic oxide.

From the viewpoint of ease of cutting the laminate 1A, the ratio of the total thickness of the base material layer 11 and the resin layer 41 (OPP thickness ratio) is 45% or more of the thickness of the laminate 1A. The ratio may be 48% or more, or 50% or more. Alternatively, the ratio of the total mass of the base material layer 11 and the resin layer 41 in the laminate 1A (OPP mass ratio) may be 45% by mass or more, 48% by mass or more, or 50% by mass or more.

The thickness of the intermediate layer 40 is not particularly limited, but may be the same as the thickness of the base layer 11, and the ratio of the thicknesses of these layers (thickness of the base layer 11/thickness of the intermediate layer 40) may be 1.00 or more, 1.25 or more, or 1.50 or more. The base material layer 11 is a portion that comes into direct contact with or is close to the heat seal bar during heat sealing, and is a portion that is particularly exposed to heat among the layers of the laminate, so that it is likely to undergo thermal contraction during heat sealing. Therefore, by making the base layer 11 thicker than the intermediate layer 40, thermal shrinkage of the base layer 11 can be suppressed.

FIG. 5 is a schematic cross-sectional view showing a laminate according to a second modification. As shown in FIG. 5, the laminate 1B includes a base layer 11, a sealant layer 20, adhesive layers 30A and 30B, and an intermediate layer 40A. In the intermediate layer 40A, the order of stacking the resin layer 41, the anchor coat layer 42, and the vapor deposition layer 43 is different from that of the intermediate layer 40 of the first modification. Specifically, the vapor deposition layer 43 of the intermediate layer 40A is closest to the base material layer 11 in the stacking direction. In the first modification, the vapor deposition layer 43 contacts the adhesive layer 30A, and the resin layer 41 contacts the adhesive layer 30B.

In each of the first modified example and the second modified example described above, the same effects as those of the above embodiment are exhibited.

The self-supporting packaging bag according to one aspect of the present disclosure is, for example, as described in [1] to [9] below, and these have been explained in detail based on the above embodiment and the above modification.
[1] A base layer containing biaxially oriented polypropylene,
a vapor deposited layer containing at least one of a metal and an inorganic oxide;
a sealant layer containing polypropylene;
A laminate comprising:
The ratio of the total mass of biaxially oriented polypropylene and polypropylene in the laminate is 90% by mass or more,
The ratio of the thickness of the base material layer to the thickness of the laminate is 45% or more,
laminate.
[2] Further comprising an anchor coat layer located between the base material layer and the vapor deposition layer,
The anchor coat layer contains a resin having a polar group,
The laminate according to [1], wherein the base layer and the anchor coat layer are coextruded layers.
[3] A base material layer containing biaxially oriented polypropylene,
an intermediate layer having a resin layer containing biaxially oriented polypropylene, and a vapor deposition layer located on the resin layer and containing at least one of a metal and an inorganic oxide;
a sealant layer containing polypropylene;
A laminate comprising:
The ratio of the total mass of biaxially oriented polypropylene and polypropylene in the laminate is 90% by mass or more,
Of the thickness of the laminate, the ratio of the total thickness of the base layer and the resin layer is 45% or more,
laminate.
[4] The intermediate layer further includes an anchor coat layer located between the resin layer and the vapor deposition layer,
The anchor coat layer contains a resin having a polar group,
The laminate according to [3], wherein the resin layer and the anchor coat layer are coextruded layers.
[5] The laminate according to any one of [1] to [4], further comprising an adhesive layer located between the base material layer and the sealant layer and containing a urethane resin.
[6] The tear strength of the laminate in the width direction, measured according to the trousers tear method described in JIS K 7128-1:1998, is 5.0 N or less, [1] to [5]. The laminate according to any one of the above.
[7] The tear strength of the laminate in the machine direction, measured according to the trousers tear method described in JIS K 7128-1:1998, is 5.0 N or less, [1] to [6]. The laminate according to any one of the above.
[8] A packaging bag made of the laminate according to any one of [1] to [7].
[9] The packaging bag according to [8], which is a pillow packaging bag.

However, one aspect of the present invention is not limited to the above embodiment, the above modification, and [1] to [9] above. One aspect of the present invention can be further modified without departing from the gist thereof.

In the above embodiment and each of the above modifications, the proportion of the total mass of polypropylene in the laminate may be 90% by mass or more. For this reason, for example, in the laminate, the mass ratio of polypropylene in one of the base layer and the resin layer may be less than 90% by mass.

In the above embodiments, the base material includes the anchor coat layer and the vapor deposition layer, but is not limited thereto. For example, a vapor deposition layer may be provided on the sealant layer. In this case, an anchor coat layer may be provided between the sealant layer and the vapor deposition layer. At this time, the sealant layer and the anchor coat layer may be coextruded layers. Alternatively, the anchor coat layer and the vapor deposition layer may be included in the base material, and the vapor deposition layer may be provided on the sealant layer. Furthermore, in each of the above modifications, the intermediate layer includes an anchor coat layer and a vapor deposited layer, but is not limited thereto. For example, a vapor deposition layer may be provided on the base material layer, or a vapor deposition layer may be provided on the sealant layer.

The present disclosure will be explained in more detail with reference to the following examples, but the present disclosure is not limited to these examples.

(Example 1)
As a base material layer, a biaxially stretched polypropylene film (manufactured by Mitsui Chemicals Tohcello Co., Ltd., "A-OP (registered trademark), BH") with a thickness of 30 μm was prepared. Further, as a sealant layer, a 25 μm thick unstretched polypropylene film (“VM-OPP, 2703” manufactured by Toray Film Processing Co., Ltd.) provided with a vapor deposition layer was prepared.

Next, a mixture of urethane adhesive (DIC Graphics Co., Ltd., "Dick Dry LX-500") and curing agent (DIC Graphics Co., Ltd., "KW-75") is applied onto the vapor deposited layer of the sealant layer. The solution was coated at a speed of 100 mm/s using a bar coater (bar No. 5, wet film thickness: 11.43 g/m ² ). Subsequently, the mixed solution was dried at 60° C. for 1 minute. Subsequently, the base material layer was laminated on the sealant layer using a hand laminator under the conditions of nip thickness: 0.3 MPa, nip temperature: 60° C., and speed: 1 m/min. Then, the laminate of the base layer and the sealant layer was allowed to stand at 40° C. for 72 hours to produce a laminate with a thickness of about 55 μm. The content of polypropylene in the obtained laminate was 90% by mass or more. In addition, the nip roll of the hand laminator used a metal roll (upper side) and a rubber roll (lower side).

(Example 2)
A biaxially stretched polypropylene film (manufactured by Toyobo Co., Ltd., "Pyrene (registered trademark), P2171") with a thickness of 20 μm was prepared as a base material layer. Further, as an intermediate layer, a 15 μm thick biaxially stretched polypropylene film (manufactured by Max Specialty Films, trade name: M15SL6) on which a vapor deposition layer was provided was prepared. In addition, an unstretched polypropylene film (manufactured by Mitsui Chemicals Tohcello Co., Ltd., "GLC") with a thickness of 40 μm was prepared as a sealant layer.

Next, a urethane adhesive (DIC Graphics Co., Ltd., "Dick Dry LX-500") and a curing agent (DIC Graphics Co., Ltd., "DIC Dry LX-500") and a curing agent (DIC Graphics Co., Ltd., A mixed solution of "KW-75") was applied at a speed of 100 mm/s using a bar coater (bar No. 5, wet film thickness: 11.43 g/m ² ). Subsequently, the mixed solution was dried at 60° C. for 1 minute. Subsequently, the base material layer, intermediate layer, and sealant layer were laminated on each other using a hand laminator under the conditions of nip thickness: 0.3 MPa, nip temperature: 60° C., and speed: 1 m/min. Then, the laminate of the base layer, intermediate layer, and sealant layer was allowed to stand at 40° C. for 72 hours to produce a laminate with a thickness of about 75 μm. The content of polypropylene in the obtained laminate was 90% by mass or more. In addition, the nip roll of the hand laminator used a metal roll (upper side) and a rubber roll (lower side).

(Example 3)
A film with a thickness of about 85 μm was prepared in the same manner as in Example 2, except that a biaxially stretched polypropylene film (manufactured by Toyobo Co., Ltd., “Pyrene (registered trademark), P2171”) with a thickness of 30 μm was prepared as the base material layer. A laminate was manufactured. The content of polypropylene in the obtained laminate was 90% by mass or more.

(Comparative example 1)
A biaxially stretched polypropylene film with a thickness of 20 μm (manufactured by Mitsui Chemicals Tohcello Co., Ltd., "A-OP (registered trademark), BH") was prepared as the base material layer, and a vapor deposition layer was provided as the sealant layer. A laminate with a thickness of about 45 μm was produced in the same manner as in Example 1, except that a 25 μm thick unstretched polypropylene film (manufactured by Toray Film Processing Co., Ltd., “VM-OPP, 2703”) was prepared. . The content of polypropylene in the obtained laminate was 90% by mass or more.

(Comparative example 2)
A biaxially stretched polypropylene film (manufactured by Mitsui Chemicals Tohcello Co., Ltd., "A-OP (registered trademark), BH") with a thickness of 30 μm was prepared as the base material layer, and a vapor deposition layer was provided as the sealant layer. A laminate with a thickness of about 70 μm was produced in the same manner as in Example 1, except that a 40 μm thick unstretched polypropylene film (manufactured by Toray Film Processing Co., Ltd., “VM-OPP, 2703”) was prepared. . The content of polypropylene in the obtained laminate was 90% by mass or more.

(Comparative example 3)
The same procedure as in Example 1 was carried out, except that a 40 μm thick unstretched polypropylene film (manufactured by Reiko Co., Ltd., "Sunmirror (registered trademark), CP-VR") on which a vapor deposition layer was provided was prepared as the sealant layer. A laminate having a thickness of approximately 70 μm was manufactured using this method. The content of polypropylene in the obtained laminate was 90% by mass or more.

(Comparative example 4)
As a base material layer, polyamide (manufactured by Ube Industries, Ltd., polyamide 6, melting point: 220°C), adhesive resin (manufactured by Mitsui Chemicals, Inc., "ADMER QF500", maleic anhydride modified polypropylene), and polypropylene (Japan Polypropylene) were used. Co., Ltd., "Novatec FL203D" (melting point: 160°C) was coextruded, and then stretched 5 times in the longitudinal direction (MD direction) and 10 times in the transverse direction (TD direction) using a sequential biaxial stretching device. , a multilayer base material with a thickness of 21 μm, comprising a surface resin layer (0.4 μm) made of polyamide, an adhesive resin layer (1 μm) made of adhesive resin, and a polypropylene resin layer (19.6 μm) made of polypropylene. prepared. In addition, a 30 μm thick unstretched polypropylene film (manufactured by Mitsui Chemicals Tohcello Co., Ltd., "CPS") was bonded to a polyurethane adhesive (manufactured by Mitsui Chemicals, Inc., "Takelac A-969V/Takenate A-5" (composition ratio 3/1). )) and then allowed to stand at 40° C. for 24 hours to produce a laminate with a thickness of about 51 μm. The content of polypropylene in the obtained laminate was 90% by mass or more.

(Comparative example 5)
A laminate with a thickness of about 105 μm was produced in the same manner as in Example 3, except that a 60 μm thick unstretched polypropylene film (manufactured by Mitsui Chemicals Tohcello Co., Ltd., “GLC”) was prepared as the sealant layer. . The content of polypropylene in the obtained laminate was 90% by mass or more.

(Tear strength of laminate)
From each of Examples 1 to 3 and Comparative Examples 1 to 5, samples S1 and S2 (long side 150 mm, short side 50 mm) having a rectangular shape in plan view as shown in FIG. 6(a) were prepared. In sample S1, the longitudinal direction corresponds to the flow direction of the laminate, and the lateral direction corresponds to the width direction of the laminate. In sample S2, the longitudinal direction corresponds to the width direction of the laminate, and the lateral direction corresponds to the flow direction of the laminate. Each of the samples S1 and S2 is provided with a notch having a length of 75 mm along the longitudinal direction. As shown in FIG. 6(b), the cut C extends in the longitudinal direction from the center of one short side to the starting point SP, which is the center of the samples S1 and S2.

Next, samples S1 and S2 of Examples 1 to 3 and Comparative Examples 1 to 5 were tested using a tensile tester (Tensilon Universal Testing Machine, "RTF-1250" manufactured by A&D Co., Ltd.). The tear strength was measured using a test speed of 200 mm/min. The tear strengths measured in each of Examples 1 to 3 are shown in Table 1 below, and the tear strengths measured in each of Comparative Examples 1 to 5 are shown in Table 2 below. In each of Tables 1 and 2 below, the measured tear strength of sample S1 corresponds to the tear strength in the machine direction, and the measured result of the tear strength of sample S2 corresponds to the tear strength in the width direction. Note that "-" in Table 2 below means that the tear strength could not be measured due to occurrence of delamination of the sample, elongation of the sealant of the sample, etc.

In addition, the distance between the end point EP of the fracture line formed on each sample after the tear strength measurement and the base point BP, which is the center of the other short side of each sample, is measured, and based on the distance, the samples S1, The straight-line cutting properties of S2 were evaluated. It can be determined that the shorter the distance, the higher the cuttability of the laminate. The evaluation results of straight-line cutability in each of Examples 1 to 3 are shown in Table 1 below, and the evaluation results of straight-line cutability in each of Comparative Examples 1 to 5 are shown in Table 2 below. In addition, when the above distance is 5 mm or less, the straight line cutability is evaluated as "A", and when the above distance is 10 mm or less, the straight line cutability is evaluated as "B", and due to the occurrence of delamination etc. If the sample was not torn, straight cutability was rated "F". Note that even in cases where the evaluation was "B", delamination and the like sometimes occurred. In Tables 1 and 2 below, "Y" is indicated when delamination occurs, and "N" is indicated when delamination does not occur. The presence or absence of sealant elongation and the presence or absence of an intermediate layer are similarly indicated.

In Examples 1 to 3 described above, neither delamination nor sealant elongation occurred in either the width direction or the machine direction, and the samples S1 and S2 were torn. In addition, both samples S1 and S2 had straight cutability of A or B, and tear strength of 1.2N or less. On the other hand, in all of Comparative Examples 1 to 5, tear strength could not be measured because delamination and sealant elongation occurred in sample S2 (ie, in the width direction). In addition, in Comparative Examples 2 to 5, the tear strength of sample S1 (ie, in the machine direction) was measured, but delamination and sealant elongation occurred. Furthermore, in Comparative Example 2, the tear strength of sample S1 exceeded 5.0N.

DESCRIPTION OF SYMBOLS 1, 1A, 1B... Laminate, 10... Base material, 11... Base material layer, 12, 42... Anchor coat layer, 13, 43... Vapor deposition layer, 20... Sealant layer, 30, 30A, 30B... Adhesive layer, 40 , 40A... intermediate layer, 41... resin layer, 100, 100A... packaging bag.

Claims (9)

a base material layer containing biaxially oriented polypropylene;
a vapor deposited layer containing at least one of a metal and an inorganic oxide;
a sealant layer containing polypropylene;
A laminate comprising:
The ratio of the total mass of biaxially oriented polypropylene and polypropylene in the laminate is 90% by mass or more,
The ratio of the thickness of the base material layer to the thickness of the laminate is 45% or more,
laminate. further comprising an anchor coat layer located between the base layer and the vapor deposition layer,
The anchor coat layer contains a resin having a polar group,
The laminate according to claim 1, wherein the base layer and the anchor coat layer are coextruded layers. a base material layer containing biaxially oriented polypropylene;
an intermediate layer having a resin layer containing biaxially oriented polypropylene, and a vapor deposition layer located on the resin layer and containing at least one of a metal and an inorganic oxide;
a sealant layer containing polypropylene;
A laminate comprising:
The ratio of the total mass of biaxially oriented polypropylene and polypropylene in the laminate is 90% by mass or more,
Of the thickness of the laminate, the ratio of the total thickness of the base layer and the resin layer is 45% or more,
laminate. The intermediate layer further includes an anchor coat layer located between the resin layer and the vapor deposition layer,
The anchor coat layer contains a resin having a polar group,
The laminate according to claim 3, wherein the resin layer and the anchor coat layer are coextruded layers. The laminate according to any one of claims 1 to 4, further comprising an adhesive layer located between the base material layer and the sealant layer and containing a urethane resin. According to any one of claims 1 to 4, the tear strength in the width direction of the laminate is 5.0 N or less, as measured in accordance with the trousers tear method described in JIS K 7128-1:1998. The laminate described. According to any one of claims 1 to 4, the laminate has a tear strength in the machine direction of 5.0 N or less, as measured in accordance with the trousers tear method described in JIS K 7128-1:1998. The laminate described. A packaging bag, which is a bag made of the laminate according to any one of claims 1 to 4. The packaging bag according to claim 8, which is a pillow packaging bag.

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