Packaging material and package

Abstract

To provide a packaging material which can be easily manufactured and is volume-reduced while satisfying required performance of a practical level, and a package.SOLUTION: A packaging material contains a polypropylene unstretched film of 15-70 μm thickness, an aluminum layer vapor-deposited on the polypropylene unstretched film, and a coat layer of 0.1-10 μm thickness on the aluminum layer.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a packaging material, particularly a packaging material used to package confectionery, and to a package made from said packaging material. [Background technology]

[0002] Gas barrier films are used as packaging materials for confectionery, etc. For example, Patent Document 1 discloses a structure of polyethylene terephthalate (PET) film / printing layer / adhesive layer / aluminum vapor deposition layer / polyethylene (PE) film, and Patent Document 2 discloses a structure of PET / aluminum vapor deposition layer / gas barrier coating layer / sealant layer (resin film). Both structures utilize two or more types of resin film.

[0003] However, these technologies require the use of two or more types of film, which requires complicated processes such as dry lamination or extrusion lamination.In addition, the use of two or more types of film and materials with high specific gravity such as PET and polyamide makes it difficult to reduce the volume of packaging materials.

[0004] When attempting to use a film having an aluminum vapor deposition layer as a packaging material by itself, it is not easy to heat seal the surfaces of the aluminum vapor deposition layer together, and since the aluminum vapor deposition layer easily falls off, it is not easy to use it in a configuration in which the aluminum vapor deposition layer is positioned as the outer layer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-52282 [Patent Document 2] Japanese Patent Application Publication No. 2020-49942 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a packaging material and a package that can be easily produced and that has a reduced volume while satisfying the required performance at a practical level. [Means for solving the problem]

[0007] The present inventors have conducted extensive research into the layer structure of packaging materials and have found that the above-mentioned problems can be solved by devising the layer structure, thereby completing the present invention.

[0008] That is, the present invention (1) is a packaging material having an unstretched polypropylene film having a thickness of 15 to 70 μm, an aluminum layer vapor-deposited on the unstretched polypropylene film, and a coating layer having a thickness of 0.1 to 10 μm on the aluminum layer.

[0009] The present invention (2) is the packaging material according to the present invention (1), wherein the coating layer is an anchor coating layer, a print coating layer or an overcoat layer.

[0010] The present invention (3) is the packaging material according to the present invention (2), which has the print coat layer on the anchor coat layer or the aluminum vapor-deposited layer.

[0011] The present invention (4) is the packaging material according to the present invention (3), which has the overcoat layer on the print coat layer.

[0012] The present invention (5) is the packaging material according to any one of the present inventions (1) to (4), wherein the unstretched polypropylene film is composed of three or more layers of polypropylene film.

[0013] The present invention (6) is a packaged body obtained by sealing the polypropylene layers of the unstretched polypropylene film of the packaging material according to any one of the present inventions (1) to (5) and processing it into a bag shape. [Effects of the Invention]

[0014] According to the present invention, it is possible to easily produce a packaging material and a package that are reduced in volume while still satisfying the required performance at a practical level. DETAILED DESCRIPTION OF THE INVENTION

[0015] <<Packaging materials>> The packaging material of the present invention is characterized by having an unstretched polypropylene film having a thickness of 15 to 70 μm, an aluminum layer vapor-deposited on the unstretched polypropylene film, and a coating layer having a thickness of 0.1 to 10 μm on the aluminum layer.

[0016] <Unstretched polypropylene film> The unstretched polypropylene film is an unstretched film made of polypropylene that has heat-sealing properties. The polypropylene constituting the unstretched polypropylene film may be copolymerized with not only propylene monomer but also other polymerizable monomers. The film may be a single layer, but is preferably a multi-layer film having three or more layers. When the film has three or more layers, it is sufficient that at least one layer is composed of polypropylene, and all layers do not need to be composed of the same polymer. For example, the film may have a layer containing the above-mentioned polypropylene copolymer or a polymer other than polypropylene. However, the layer that will become the innermost layer when processed into a package must have heat-sealing properties. The melting point of the polypropylene constituting the innermost layer is preferably lower than the melting points of the polypropylenes constituting the other layers.

[0017] The unstretched polypropylene film can be produced by methods such as extrusion using a T-die or inflation. When the unstretched polypropylene film has a multilayer structure, it can be produced by a known method such as multilayer co-extrusion using two or more resins. The thickness of the unstretched polypropylene film is 15 to 70 μm, but preferably 20 to 50 μm. If it is less than 15 μm, the rigidity of the substrate is insufficient. If it exceeds 70 μm, the temperature difference between the sealed layer and the outermost layer during heat sealing becomes large, and the amount of heat applied to the outermost layer increases, resulting in significant deformation of the edge of the sealed portion and making the sealed portion more likely to tear, which is undesirable.

[0018] <Aluminum layer> The aluminum layer is a layer formed directly on an unstretched polypropylene film and provides gas barrier properties, water vapor barrier properties, and light-shielding properties. The method for forming the aluminum layer is not particularly limited, and examples include physical vapor deposition methods such as vacuum deposition, sputtering, and ion plating, and plasma chemical vapor deposition. The thickness of the aluminum layer is preferably 5 nm to 300 nm, and more preferably 10 to 100 nm. If the thickness is less than 5 nm, it is difficult to obtain a uniform film and the gas barrier properties tend to be insufficient. If the thickness exceeds 300 nm, cracks tend to occur in the vapor-deposited layer due to external factors such as bending and tension during processing.

[0019] <Coating layer> The coating layer is not a film like a molded product, but a layer formed by coating. Examples of coating layers include an anchor coating layer formed for adhesion to the aluminum layer, a printed coating layer formed to impart design to the packaging material, and an overcoat layer formed to protect the entire non-heat-sealed surface of the packaging material and to facilitate peeling from the seal bar during heat sealing. These coating layers as a whole prevent and protect the aluminum layer from cracking, shedding, and corrosion. It is not necessary to form all three of these layers; at least one coating layer is sufficient. The various coating layers mentioned above can be, for example, polyester-based resins, polyamide-based resins, polyurethane-based resins, epoxy-based resins, phenol-based resins, acrylic-based resins, polyvinyl acetate-based resins, polyvinyl chloride-based resins, vinyl chloride-vinyl acetate copolymers, polyolefin-based resins such as polyethylene or polypropylene, or copolymers or modified resins, or resin compositions containing cellulose-based resins as the main vehicle component.

[0020] The anchor coat layer is not particularly limited, and can be formed using a commercially available coating agent that has adhesive properties to the aluminum layer. Specific coating agents include, for example, acrylic resins, urethane resins, polyester resins, etc., and coating agents containing other resins, fillers, other components, etc. as needed. While there are no particular limitations on the resins, aqueous polymers containing acrylic resins as the main component are preferred.

[0021] The overcoat layer is not particularly limited and can be formed using a commercially available coating agent having abrasion resistance, etc. Specific coating agents include, for example, acrylic resins, vinyl chloride-vinyl acetate copolymers, etc., and coating agents containing other resins, fillers, other components, etc. as needed. The resins mentioned above are not particularly limited, but oil-based polymers are preferred.

[0022] The printing coating layer is not particularly limited and can be formed using a coating agent including commercially available ink or paint. Printing ink mainly contains pigment, solvent, binder, additives, etc. Specific coating agents include, for example, acrylic resin, polyurethane resin, epoxy resin, etc., and coating agents containing other resins, fillers, other components, etc. as needed.

[0023] The thickness of the coating layer is preferably 0.1 to 10 μm, more preferably 0.5 to 8 μm, and even more preferably 1.5 to 5 μm. If the thickness is less than 0.1 μm, it is difficult to obtain a uniform film, and if the thickness exceeds 10 μm, it is difficult to dry sufficiently in the process, which is not preferable. When the coating layer is formed from multiple layers, the thickness of each coating layer is preferably 0.2 to 3 μm.

[0024] The method for forming the coating layer is not particularly limited, and examples thereof include spray coating, offset printing, screen printing, flexographic printing, dip coating, roll coating, bar coating, spin coating, casting, die coating, blade coating, gravure coating, curtain coating, doctor coating, slit coating, etc. Among these, gravure coating is preferred because it is capable of coating a thin film of a low-viscosity resin.

[0025] In the present invention, it is preferable to form the coating layer by applying the above-mentioned coating layer onto an unstretched polypropylene resin film having an aluminum vapor-deposited layer by the above-mentioned known coating method, followed by drying.

[0026] Specific layer configurations of the packaging material of the present invention include the following: Here, PPF means unstretched polypropylene film, AL layer means aluminum layer, AC layer means anchor coat layer, PR layer means print coat layer, and OC layer means overcoat layer. (1) PPF / AL layer / / OC layer (3 layers) (2) PPF / AL layer / PR layer / OC layer (4 layers) (3) PPF / AL layer / AC layer / PR layer (4 layers) (4) PPF / AL layer / AC layer / PR layer / OC layer (5 layers)

[0027] <<Packaging>> The packaging material of the present invention is characterized in that the polypropylene of the unstretched polypropylene film of the packaging material of the present invention is sealed together and processed into a bag shape. The packaging material of the present invention can be used for food applications such as sweets and toiletries, and is particularly suitable for use as packaging in cartons.

[0028] A specific example of a method for producing a package includes the following steps. (1) Supply the contents onto the film (2) Form the film into a cylindrical shape and seal the ends of the film. (3) Seal the film at the bottom of the package. (4) Seal the film that will become the top of the package. (5) Cut each seal and separate the packages.

[0029] As the sealing method, known methods can be used, such as heat sealing, ultrasonic sealing, sealing using an adhesive, etc. For example, by heat sealing such as heat fusing together the polypropylene of an unstretched polypropylene film having an aluminum vapor deposition layer, it is possible to prepare packages in the form of pillow packaging, three-side sealing, four-side sealing, gusset type, etc.

[0030] In heat sealing, the polypropylene of the packaging material, unstretched polypropylene film, is overlapped and heated to melt and bond the contacting surfaces of the films into a bag. Pressure conditions for heat sealing include, for example, a sealing temperature of 120 to 170°C, a sealing pressure of 0.05 to 0.3 MPa, and a sealing time of 0.3 to 3 seconds.

[0031] The seal strength of the package obtained by heat-sealing the packaging material is preferably 7 N / 15 mm or more, more preferably 10 N / 15 mm or more. There is no particular upper limit to the seal strength. The seal strength is measured by cutting a 15 mm wide piece perpendicular to the heat-sealed portion and using a tensile tester at a pulling speed of 300 mm / min and a 180-degree peel angle. [Example]

[0032] The present invention will be described below with reference to examples, but is not limited to these examples. Hereinafter, "parts" and "%" mean "parts by mass" and "% by mass", respectively, unless otherwise specified.

[0033] Example 1 The unstretched polypropylene film used was a 40 μm-thick, three-layered polypropylene film (F77, manufactured by AIC Tech Co., Ltd.) with an aluminum vapor-deposited layer on one surface. The aluminum vapor-deposited layer surface was coated with a water-based anchor coating agent (Z319VM Anchor Varnish, manufactured by Toyo Ink Co., Ltd.) primarily composed of acrylic resin by gravure roll coating, and then heat-treated at 75°C for 10 seconds.

[0034] Next, a printing coating layer (Lio Alpha S, manufactured by Toyo Ink Co., Ltd.) was formed on the surface of the anchor coating agent layer by gravure roll coating, and then heat-treated at 75°C for 10 seconds. The thickness of the anchor coating layer in the dried state was adjusted to 0.8 µm, and the printing coating layer was adjusted to 1.0 µm, to produce a barrier laminate film.

[0035] Example 2 An oil-based overprint varnish (Z309 Gloss OP Varnish, manufactured by Toyo Ink Co., Ltd.) containing a vinyl chloride-vinyl acetate copolymer as its main component was coated on the printed coating layer surface of the barrier laminate film described in Example 1 by gravure roll coating, and then the coating was heated at 75°C for 10 seconds to a dry thickness of 1.5 µm, thereby producing a barrier laminate film on which an overprint varnish layer was formed.

[0036] Example 3 A barrier laminate film of Example 3 was produced in the same manner as in Example 2, except that the thickness of the printed coating layer in a dry state was 5.0 μm.

[0037] Example 4 A barrier laminate film of Example 4 was produced in the same manner as in Example 2, except that the anchor coat layer was not coated.

[0038] Example 5 A barrier laminate film of Example 5 was produced in the same manner as in Example 1, except that a 30 μm aluminum-deposited polypropylene unstretched film (F66, manufactured by AIC Tech Co., Ltd.) was used instead of the 40 μm aluminum-deposited polypropylene unstretched film in Example 1.

[0039] Example 6 A barrier laminate film of Example 6 was produced in the same manner as in Example 4, except that a 30 μm aluminum-deposited polypropylene unstretched film (F66, manufactured by AIC Tech Co., Ltd.) was used instead of the 40 μm aluminum-deposited polypropylene unstretched film in Example 4.

[0040] Example 7 A barrier laminate film of Example 7 was produced in the same manner as in Example 1, except that a 25 μm aluminum-deposited polypropylene unstretched film (F77, manufactured by AIC Tech Co., Ltd.) was used instead of the 40 μm aluminum-deposited polypropylene unstretched film in Example 1.

[0041] Example 8 A barrier laminate film of Example 8 was produced in the same manner as in Example 4, except that a 25 μm aluminum-deposited polypropylene unstretched film (F77, manufactured by AIC Tech Co., Ltd.) was used instead of the 40 μm aluminum-deposited polypropylene unstretched film in Example 4.

[0042] Comparative Example 1 A 40 μm aluminum-deposited unstretched polypropylene film (F77, manufactured by AIC Tech Co., Ltd.) was used as is without coating.

[0043] Reference example 1 The laminate was fabricated by laminating the vapor-deposited surface of a 25 μm aluminum-deposited unstretched polypropylene film (F77, manufactured by AIC Tech Co., Ltd.) and a 12 μm PET film (H100C, manufactured by Mitsubishi Chemical Corporation) using the dry lamination method.

[0044] The packaging materials of Examples, Comparative Examples, and Reference Examples were evaluated by the following methods. Table 1 shows the layer structure and the evaluation results.

[0045] <Seal strength> Using a heat sealer (TP-701-B manufactured by Tester Sangyo Co., Ltd.), the seal was made with a heat plate adjusted to the specified temperature for 1 second at a sealing pressure of 1 kg / cm. 2 A 15 mm wide piece was cut out perpendicular to the heat-sealed portion, and the seal strength was measured using a tensile tester at a pulling speed of 300 mm / min and 180-degree peeling.

[0046] <Heat resistance> When heat sealing was performed at 150°C, if there was no adhesion to the heated hot plate or melting of the heated part, it was marked as ◯, and if there was, it was marked as x.

[0047] <Wear resistance> Using a flat surface abrasion tester (manufactured by Daiei Scientific Instruments Manufacturing Co., Ltd., PA-300A), steel wool was attached to the abrasion element, and an abrasion test was performed in which the abrasion element was moved back and forth 30 times with a 500 g weight placed on it.The extent to which the aluminum vapor deposition layer had worn away from the test area was visually observed and evaluated according to the following criteria. If the worn area is 90% or more: × If the wear area is between 10% and 90%: YES If the worn area is less than 10%:

[0048] <Packaging material weight ratio> The calculation was made assuming that the weight of the packaging material in Reference Example 1 was 100%. The specific gravity of the PP film was 0.9, and the specific gravity of the PET film was 1.34.

[0049] [Table 1]

[0050] As shown in Examples 1 to 8, by providing a coating layer on the aluminum layer, it was possible to achieve both heat resistance and abrasion resistance. In addition, it was possible to achieve a greater weight reduction than the conventional packaging material produced by laminating PP and PET films as shown in Reference Example 1. When no coating layer was provided, the heat resistance and abrasion resistance were inferior as shown in Comparative Example 1.

Claims

1. an unstretched polypropylene film having a thickness of 15 to 70 μm; an aluminum layer vapor-deposited on the unstretched polypropylene film; and The packaging material has a coating layer having a thickness of 0.1 to 10 μm on the aluminum layer.

2. 2. The packaging material according to claim 1, wherein the coating layer is an anchor coating layer, a printing coating layer, or an overcoat layer.

3. The packaging material according to claim 2, wherein the printing coat layer is disposed on the anchor coat layer or the aluminum vapor deposition layer.

4. 4. The packaging material according to claim 3, further comprising an overcoat layer on the print coat layer.

5. 3. The packaging material according to claim 1, wherein the unstretched polypropylene film is composed of three or more layers of polypropylene film.

6. A packaged body obtained by sealing the polypropylene layers of the unstretched polypropylene film of the packaging material according to claim 1 or 2 together and processing it into a bag shape.

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