Packaging film

Abstract

To reduce an amount of plastic used in a case of printing a design on a packaging film using a vapor-deposited film.SOLUTION: A packaging film includes: a vapor-deposited film including a substrate layer and a vapor-deposited layer provided on one surface of the substrate layer; and a design layer provided on a surface of the vapor-deposited film on the vapor-deposited layer side. A surface of the substrate layer opposite to the vapor-deposited layer has heat sealability. The design layer includes an anchor coat layer, a printed layer, and a top coat layer sequentially from the vapor-deposited film side. The printed layer is formed by printing through use of ink. The anchor coat layer contains an acrylic resin or an urethane resin and is formed by using an aqueous anchor coat agent containing an acrylic resin or an urethane resin.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a packaging film. [Background technology]

[0002] Vapor-deposited films such as aluminum vapor-deposited films are sometimes used as packaging films for foods such as snacks, instant noodles, and frozen foods (see, for example, Patent Documents 1 and 2). Vapor-deposited films are excellent in barrier properties against oxygen and water vapor, light-blocking properties, and design properties (metallic luster). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Jikko No. 61-2036 [Patent Document 2] Japanese Patent Application Publication No. 7-125133 Summary of the Invention [Problem to be solved by the invention]

[0004] When a design is applied to a package using a vapor-deposited film having a heat-seal layer, it is common to prepare a laminated film by laminating a film to which a design has been applied in advance by printing or the like onto the vapor-deposited layer side of the vapor-deposited film, and then use the laminated film to prepare a package (see Patent Documents 1 and 2). When applying a design to a vapor-deposited film without laminating a film with a pre-designed design, the base layer (resin layer) side of the vapor-deposited film is heat-sealed when the packaging bag is made, so printing is done on the vapor-deposited layer side, but printing on the surface of the vapor-deposited layer side (vapor-deposited surface) is difficult. For vapor-deposited layers such as metal vapor-deposited layers, it is difficult to obtain adhesion to the vapor-deposited surface with inks used in general gravure printing, and also, it is difficult to print on the vapor-deposited surface with organic solvents. layer In addition, the alkaline nature of water-based inks can cause problems such as poor adhesion between the ink and the film (substrate). layer There is a risk of corrosion of materials (such as aluminum).

[0005] Examples of films to which designs can be applied include PET (biaxially oriented polyethylene terephthalate), OPP (biaxially oriented polypropylene), etc. Examples of laminated films obtained by laminating a film to which a design has been applied onto an aluminum vapor-deposited film via an adhesive such as dry lamination include PET (printed) / vapor-deposited CPP (unoriented polypropylene) and OPP (printed) / vapor-deposited CPP.

[0006] Thus, in order to impart a design to a packaging film using a vapor-deposited film, it was necessary to separately laminate a film to which a design had been imparted. However, due to environmental considerations, there is a demand to reduce the amount of plastic used (reduce CO2 emissions).

[0007] An object of the present invention is to reduce the amount of plastic used when printing designs on packaging films that use vapor-deposited films. [Means for solving the problem]

[0008] The packaging film of the present invention comprises: a vapor-deposited film including a substrate layer and a vapor-deposited layer provided on one surface of the substrate layer; and a design layer provided on the vapor-deposited layer side of the vapor-deposited film. The surface of the substrate layer opposite to the vapor deposition layer has heat sealability. The design layer includes, in order from the vapor-deposited film side, an anchor coat layer, a print layer, and a top coat layer. The print layer is formed by printing with ink. The anchor coat layer contains an acrylic resin or a urethane resin, and is formed using a water-based anchor coat agent containing an acrylic resin or a urethane resin. [Effects of the Invention]

[0009] According to the present invention, when a design is printed on a packaging film using a vapor-deposited film, the amount of plastic used can be reduced. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing a packaging film according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings, in which the same or common parts are designated by the same reference numerals.

[0012] <Packaging film> Referring to FIG. 1, a packaging film 1 of this embodiment includes a vapor-deposited film 2 and a design layer 3. The packaging film 1 of this embodiment is a film used as a material for packaging (bags, etc.) for food, etc. Details of the packaging film 1 will be described below.

[0013] [Vapor-deposited film] The vapor-deposited film 2 includes a base layer 21 and a vapor-deposited layer 22 provided on one surface of the base layer 21 .

[0014] (deposited layer) The vapor-deposited layer 22 of the vapor-deposited film 2 is a layer formed by vapor-depositing a metal, metal oxide, or the like onto the base layer 21.

[0015] Although various metals can be used as the metal, aluminum is preferably used because it is inexpensive, can provide a metallic design with its metallic luster, and also provides light-blocking properties. That is, the vapor-deposited film 2 is preferably a film on which aluminum is vapor-deposited (aluminum vapor-deposited film). Examples of metal oxides include versatile aluminum oxide (AlOx), silicon oxide (SiOx), etc. In addition to these, various organic compounds, inorganic compounds, etc. can also be used as the material for the deposition layer 22.

[0016] The deposition method is not particularly limited, but examples thereof include vacuum deposition, which is a physical deposition method, and CVD (chemical vapor deposition), which is a chemical deposition method.

[0017] The thickness of the vapor deposition layer 22 is not particularly limited as long as it can exhibit the desired properties such as light blocking, moisture resistance, and gas barrier properties, but is preferably 5 to 100 nm, and more preferably 20 to 70 nm in the case of aluminum vapor deposition.

[0018] (base material layer) The base layer 21 is made of, for example, a resin film. The resin used as the material for the resin film is preferably a thermoplastic resin. The resin film may be stretched or unstretched. Stretched resin films have excellent dimensional stability and rigidity.

[0019] The surface of the base layer 21 opposite to the vapor deposition layer 22 has heat sealability. By heat-sealing the deposited film 2 with the base layer 21 side (opposite to the deposited layer 22) facing each other as the heat-sealing surface, a packaging bag or the like can be produced using the packaging film 1 of this embodiment. For this reason, it is preferable that the base layer 21 of the vapor-deposited film 2 be made of a heat-sealable sealant film (single layer or multiple layers obtained by co-extrusion). In this case, the processing step of laminating a separate sealant film or heat-sealing agent is unnecessary, and the number of films to be laminated can be reduced, which simplifies the manufacturing process, reduces the cost of film materials, and enables the overall thickness of the laminated film to be reduced.

[0020] Examples of heat-sealable vapor-deposited films 2 (where the base layer 21 is composed of a sealant film) include aluminum-deposited non-oriented polypropylene (VMCPP), heat-sealable aluminum-deposited biaxially oriented polypropylene (VMOPP), aluminum-deposited linear low-density polyethylene (VMLLDPE), aluminum-deposited high-density polyethylene (VMHDPE), and aluminum-deposited low-density polyethylene (VMLDPE). That is, examples of materials for the base layer 21 having heat sealability include resins that can be used as sealant films, such as polypropylene (PP), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and low-density polyethylene (LDPE).

[0021] If the base layer 21 of the vapor-deposited film 2 has poor heat-sealability on the surface opposite to the vapor-deposited layer 22, a separate sealant layer may be laminated thereon. Examples of materials that can be used to form the sealant layer include single-layer or multi-layer films or extrusion laminates (extrusion coatings) made of ethylene copolymers such as unoriented polypropylene (CPP), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), low-density polyethylene (LDPE), and ethylene-vinyl acetate copolymer (EVA), as well as layers coated with a solution or emulsion of a heat-sealable resin such as a polyethylene copolymer. When such a sealant layer is present, the combination of materials for the vapor-deposited film 2 / sealant layer in the packaging film 1 may be, for example, VMPET (aluminum-deposited PET) / LDPE (low-density PE).

[0022] However, from the viewpoint of reducing the amount of plastic used, it is preferable that the base layer 21 is a sealant film having heat sealing properties, and it is preferable not to provide a separate sealant layer. When the base layer 21 has heat-sealing properties, examples of the material for the vapor-deposited film 2 in the packaging film 1 include VMCPP (aluminum-deposited CPP).

[0023] The thickness of the base layer 21 is not particularly limited, but is preferably 10 to 200 μm, and more preferably 40 to 150 μm. If the thickness of the base layer 21 (deposited film 2) is too thin, the sealing strength, rigidity, moisture resistance, etc. of the packaging film 1 may be insufficient, and if the thickness is too thick, there is a risk that the suitability for processing such as printing may be poor. From the viewpoint of reducing the amount of plastic used, it is preferable that the thickness of the vapor-deposited film 2 (substrate layer 21) be as thin as possible.

[0024] [Design layer] The design layer 3 is provided on the surface of the vapor-deposited film 2 on the vapor-deposited layer 22 side. The design layer 3 includes, in order from the vapor-deposited film 2 side, an anchor coat layer 31 (in contact with the vapor-deposited layer 22), a printing layer 32 (in contact with the anchor coat layer 31), and a top coat layer 33. The top coat layer 33 only needs to be provided on the side of the printed layer 32 opposite the deposited film 2, and may be in contact with the printed layer 32 or may not be in direct contact with it via another coating layer.

[0025] (Anchor coat layer) The anchor coat layer 31 has the function of increasing the adhesion of the printed layer 32 formed thereon using ink. Furthermore, although the vapor deposition layer 22 (aluminum vapor deposition layer, etc.) is vulnerable to alkaline water-based ink (it can be eroded by dissolution, etc.), the anchor coat layer 31 also has the function of protecting the vapor deposition layer 22 from alkaline water-based ink, etc.

[0026] The anchor coat layer 31 contains an acrylic resin or a urethane resin. The anchor coat layer 31 is formed using an aqueous anchor coat agent containing an acrylic resin or a urethane resin. The aqueous anchor coat agent is a coating liquid obtained by dissolving an acrylic resin or a urethane resin in an aqueous solvent or dispersing it as an emulsion or dispersion. Examples of aqueous anchor coating agents include those commercially available from Sakata Inx Corporation, Toyo Ink Co., Ltd., and the like (for example, "Aqua Anchor Varnish" from Toyo Ink Co., Ltd.).

[0027] In this specification, an aqueous solvent is a solvent (solvent) containing water as the main component (a component accounting for 50% by mass or more of the total). The aqueous solvent may contain components other than water, such as alcohol (e.g., isopropyl alcohol), but from an environmental perspective, it is preferable that the content of organic solvents is low. The proportion of water in the aqueous solvent is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 95% by mass or more. The aqueous solvent may also be water only, without any other components. When the aqueous solvent contains alcohol, the alcohol content is preferably 10% or less, and more preferably 5% or less.

[0028] The pH of the anchor coating agent is preferably lower than the pH of the printing ink (water-based ink) described below, more preferably pH 6.5 to 8.0. In this case, the anchor coating layer 31 can prevent the deposition layer 22 from being corroded by the alkaline water-based ink.

[0029] The anchor coating agent is preferably one that is primarily composed of an aqueous emulsion, with at least 50%, preferably at least 70%, of the resin component being emulsion. In this case, it is possible to prepare an aqueous anchor coating agent containing an acrylic resin or urethane resin without using an alkali agent or by using a small amount of alkali agent, and the pH of the anchor coating agent can be adjusted to a neutral range lower than the pH of the aqueous ink.

[0030] The thickness of the anchor coat layer is not particularly limited, but is about 0.1 to 10 μm, and preferably 0.1 to 2 μm.

[0031] The method for forming the anchor coat layer 31 is not particularly limited, but flexographic printing, gravure printing, or the like can be used, as with the printing layer 32 described below. Alternatively, the anchor coat layer 31 may be formed by applying a liquid (coating liquid) containing the constituent materials to the surface of the vapor deposition layer 22 or the printing layer 32 using a roll coater or the like, and then drying the liquid.

[0032] The anchor coat layer 31 may be formed so as to cover the entire surface of the vapor deposition layer used as the packaging film, but it is sufficient that it is formed at least in the area where the printed layer is to be provided.

[0033] (Printing layer) The print layer 32 is a layer containing a coloring material and the like that forms the design to be applied to the packaging film 1. The printed layer 32 can be formed in a single color or in multiple colors by printing using ink containing a coloring material in a position and area according to the design.

[0034] The method for forming the printed layer 32 (the method for printing ink onto the anchor coat layer 31) is not particularly limited, and flexographic printing, gravure printing, letterpress printing, offset printing, etc. can be used. It is preferable to form the printing layer 32 using flexographic printing. For example, if the base layer 21 is a stretchy film such as a non-stretched film, the film is pulled during gravure printing, which may cause the film to stretch and reduce printing accuracy. Center drum flexographic printing is a relief printing method in which a film is wrapped around a drum and a flexible rubber or resin plate is used, and because the film is less likely to stretch, more accurate printing is possible.

[0035] The ink (printing ink) used to form the printed layer 32 is preferably a water-based ink. In recent years, environmental considerations have led to calls for a reduction in the amount of organic solvents used (especially VOCs (volatile organic compounds)). If the printed layer 32 is formed using a water-based ink that does not use organic solvents, the amount of organic solvent used can be reduced. In addition, the need for VOC combustion treatment can be reduced, which also leads to a reduction in CO2 emissions.

[0036] The water-based ink contains a colorant and a water-based solvent, and may further contain a vehicle component, auxiliary components, and the like. The print layer 32 can also be formed using oil-based ink, the solvent of which is an oil-based solvent (organic solvent).

[0037] Colorants are materials (components) used to color printing inks. Dyes or pigments (organic or inorganic) are used as colorants. Examples of inorganic pigments include titanium oxide, red iron oxide, and extender pigments. The aqueous solvent is the same as that of the anchor coating agent described above.

[0038] The vehicle component has the function of transferring and fixing the colorant in the ink to the printed material. The vehicle component may also have the function of improving the dispersibility of the colorant and improving the physical properties of the printed layer 32 (the coating film formed by printing the ink). As the vehicle component, various natural resins and synthetic resins can be used. The water-based ink preferably contains a vehicle component as the main component (a component that accounts for 50% by mass or more of the total).

[0039] The water-based ink preferably contains an alkali-soluble resin as the main component of the vehicle. An alkali-soluble resin is a resin that can be made water-soluble by neutralizing it with an alkali component. The alkali-soluble resin has, for example, a carboxyl group (-COOH), and can be made water-soluble by neutralizing the carboxyl group with an alkali component. The alkali-soluble resin has excellent pigment dispersibility.

[0040] Water-based inks can be prepared by dissolving alkali-soluble resins in water with volatile alkali agents such as ammonia or ethanolamine. The volatile alkali agent evaporates as the water-based ink dries (evaporates). Prints made from dried water-based ink (alkali-soluble resins) are water-resistant because they do not dissolve in neutral or acidic water.

[0041] Thus, aqueous inks obtained by solubilizing resins and the like in aqueous solvents are often alkaline, and alkaline aqueous inks have a pH of, for example, 8.5 to 9.5.

[0042] The water-based ink may be a water-based emulsion, but it is preferable that the ink contains a coloring pigment and is based mainly on an alkali-soluble resin, which is easy to adjust.

[0043] Examples of auxiliary components include silicon-based antifoaming agents, polyethylene wax as a lubricant, pigment dispersants, surfactants (leveling agents), and the like.

[0044] The thickness of the printing layer is not particularly limited, but is preferably 0.3 to 10 μm.

[0045] (Top coat layer) The topcoat layer 33 has strength, abrasion resistance, slipperiness, etc. to protect the printed layer 32 . The top coat layer 33 preferably has transparency. The top coat layer 33 may have a glossy finish or a matte finish. In addition, it is preferable that the top coat layer 33 has heat resistance to heat sealing.

[0046] By providing the topcoat layer 33, it is possible to protect the printed layer 32 and the vapor deposition layer 22 in the portion where the printed layer 32 is not present and the vapor deposition surface is exposed.

[0047] The coating agent for the topcoat layer 33 is not particularly limited, but examples include OP (overprint) varnish. OP varnish is a transparent, translucent, or matte varnish applied to the surface of a printed layer, such as letters or a design. Unlike printing ink, it does not contain color pigments and can protect the printed surface. Varnish is a liquid paint made by dissolving or dispersing natural or synthetic resins in a solvent, and contains added abrasion-resistant materials and lubricants. Furthermore, as mentioned above, varnishes have heat resistance to heat sealing, and in particular, some varnishes are made of curable polyurethane resins, polyester resins, polyamide resins, acrylic resins, etc., such as polyester-based polyurethanes, which are applied with a curing agent to minimize the impact on the printed layer, vapor-deposited layer, and base layer even when in contact with a heated heat-sealing tool.

[0048] The solvent for the varnish may be an oil-based solvent (organic solvent), but from the viewpoint of reducing the amount of organic solvent used, it is preferable that it is an aqueous solvent, i.e., the varnish is preferably an aqueous varnish.

[0049] The thickness of the topcoat layer 33 is not particularly limited, but is about 0.1 to 10 μm, and preferably 0.5 to 8 μm.

[0050] The method for forming the top coat layer 33 is not particularly limited, but similar to the anchor coat layer 31 described above, the top coat layer 33 can be formed by a printing method such as flexographic printing or gravure printing, or by applying and drying a coating liquid using a roll coater or the like.

[0051] It is preferable that the anchor coat layer 31, the printing layer 32, and the top coat layer 33 are formed by the same method. In this case, the anchor coat layer 31, the printing layer 32, and the top coat layer 33 can be formed using a single manufacturing facility, which allows for simplification and efficiency of the manufacturing process.

[0052] (packaging) The packaging film 1 can be used for packaging processing or bag-making processing (production of packaging bags). During packaging processing or bag-making processing, the surfaces of the packaging film 1 opposite to the vapor-deposited layer 22 of the vapor-deposited film 2 (the substrate layer 21 side) are placed face to face, and a heated heat seal bar or the like is pressed against the top coat side (the outermost surface of the packaging film) to heat seal the two surfaces. For example, by stacking two sheets of packaging film 1 with the base layer 21 side facing each other and heat-sealing the edges of three of the four sides of the packaging film 1, a packaging bag can be produced with the remaining side open. In addition, when the base material layer 21 has heat-sealing properties, the base material layers 21 can be heat-sealed together to produce packaging materials such as packaging bags and pillow packaging that are sealed on three sides or four sides.

[0053] The present invention is not limited to the above-described embodiment, and can be modified in various ways. Two or more embodiments selected from the various embodiments described above may be combined as appropriate, or at least one configuration (part of a configuration) selected from the various embodiments described above may be replaced with part of a configuration of another embodiment.

[0054] <Summary> The following will exemplify the above-described embodiments of the present invention.

[0055] (1) a vapor-deposited film including a substrate layer and a vapor-deposited layer provided on one surface of the substrate layer; a design layer provided on the vapor-deposited layer side of the vapor-deposited film, the surface of the substrate layer opposite to the vapor deposition layer has heat sealability; the design layer includes, in order from the vapor-deposited film side, an anchor coat layer, a printing layer, and a top coat layer; the printed layer is formed by printing with ink, The anchor coat layer contains an acrylic resin or a urethane resin and is formed using an aqueous anchor coat agent containing an acrylic resin or a urethane resin. Packaging film.

[0056] (2) The packaging film according to (1), wherein the ink is a water-based ink.

[0057] (3) The packaging film according to (2), wherein the water-based ink is alkaline and the pH of the anchor coating agent is lower than the pH of the water-based ink.

[0058] (4) The packaging film according to (2), wherein the top coat layer is formed using a water-based varnish. [Explanation of symbols]

[0059] 1. Packaging film 2. Vapor-deposited film 21 Base material layer 22 Deposited layer 3 Design Layer 31 Anchor coat layer 32 Printing layer 33 Topcoat layer

Claims

1. a vapor-deposited film including a substrate layer and a vapor-deposited layer provided on one surface of the substrate layer; a design layer provided on the vapor-deposited layer side of the vapor-deposited film, the surface of the substrate layer opposite to the vapor deposition layer has heat sealability; the design layer includes, in order from the vapor-deposited film side, an anchor coat layer, a printing layer, and a top coat layer; the printed layer is formed by printing with ink, The anchor coat layer contains an acrylic resin or a urethane resin and is formed using an aqueous anchor coat agent containing an acrylic resin or a urethane resin. Packaging film.

2. 2. The packaging film according to claim 1, wherein the ink is a water-based ink.

3. 3. The packaging film according to claim 2, wherein the aqueous ink is alkaline, and the pH of the anchor coating agent is lower than the pH of the aqueous ink.

4. The packaging film according to claim 2 , wherein the top coat layer is formed using a water-based varnish.

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