JP7151859B2 - Packaging material and its manufacturing method, packaging container and lid - Google Patents

Description

TECHNICAL FIELD The present invention relates to a packaging material, a manufacturing method thereof, and a packaging container using the packaging material, particularly a packaging material that can be used in a microwave oven, a manufacturing method thereof, a packaging container, and a lid.

Packaging materials are sometimes decorated with a high-brightness metallic luster from the viewpoint of producing a sense of quality and splendor of the objects to be packaged and creating a beautiful appearance. As such decoration means, for example, forming a metal layer with a metal deposition film or a metal foil is generally performed.
However, among such packaging materials, for example, those used for packaging containers used in microwave ovens, if the surface of the packaging material is formed of the above-described metal layer, the microwave in the microwave oven is reflected on the surface of the metal layer, sparks are generated, and there is a danger that the microwave oven will malfunction or an accident will occur, and the contents in the packaging container cannot be heated sufficiently.

In response to this, for example, in Patent Document 1, by forming a glossy layer with an ink containing a high-brightness aluminum paste of a predetermined concentration, it has a high appearance and does not easily deteriorate even when heated in a microwave oven. It is stated that a package is obtained.

JP 2017-81589 A

By the way, some packaging containers such as pouches for microwave ovens are subjected to retort treatment for pressurized heat sterilization after containing contents such as food in the packaging container. In some cases, the above high temperature treatment, so-called high retort treatment, is applied. A package formed with a metallic luster layer made of a high-brightness aluminum paste as described in Patent Document 1, especially when subjected to cooking in a microwave oven after high-retort processing, is exposed to the high-brightness aluminum paste. It is difficult to say that the deterioration is sufficiently suppressed, and it cannot be said that the safety in cooking with heat in a microwave oven is sufficient.

Therefore, among packaging materials such as those used in microwave ovens, in order to create an aesthetic appearance due to metallic luster, it is necessary to form a metallic luster layer other than the above-described metallic layer or a metallic luster layer made of high-brightness aluminum paste. Other means are sought.

The present invention has been made to solve the above technical problems, and includes a packaging material capable of producing an aesthetic appearance due to metallic luster without using a metal layer or high-brightness aluminum paste, a method for manufacturing the packaging material, and the above packaging material. An object of the present invention is to provide a packaging container and a lid using a packaging material.

In the present invention, by using a pearl pigment, it is possible to obtain a packaging material that can create a beautiful appearance with a metallic luster without using a high-brightness aluminum paste, and the packaging material can be used in a microwave oven. , which was found to be superior in safety.

That is, the present invention provides the following [1] to [10].
[1] A packaging material having a configuration in which at least a plastic film, a glossy print layer and a sealant layer are laminated in this order from the outer layer side, and an adhesive layer between the glossy print layer and the sealant layer. , wherein the glossy print layer contains a pearl pigment and contains 0.0001% by mass or more and 0.01% by mass or less of carbon black (provided that the adhesive layer contains an average particle size of 20 μm or more Alternatively, those containing decorative pigments containing pigments with a particle size of 40 μm or more are excluded.).
[2] The packaging material according to [1] above, wherein the pearl pigment includes at least one selected from white pearl pigments and interference pearl pigments, and at least one selected from colored pearl pigments.
[3] The packaging material according to the above [1] or [2], which is for a microwave oven.
[4] In the method for producing a packaging material according to any one of [1] to [3] above, the glossy print layer is formed of an ink containing the pearl pigment, and the solvent contained in the ink is A method for producing a packaging material, characterized in that the boiling point at 1 atm is 150°C or less.

[5] A packaging container at least partially formed of the packaging material described in [1] or [2] above.
[6] The packaging container according to [5] above, wherein the packaging container is a pouch.
[7] A lidded container comprising a container body having an accommodating portion and a lid joined to the container body so as to seal the accommodating portion, wherein the lid is formed of the packaging material. The packaging container according to [5] above.
[8] The packaging container according to any one of [5] to [7] above, which is for a microwave oven.
[9] The packaging container according to any one of [5] to [8] above, which is a retort container.
[10] A lid made of the packaging material according to any one of [1] to [3] above.

ADVANTAGE OF THE INVENTION According to this invention, the packaging material which can produce the aesthetic appearance by metallic luster can be provided, without using a metal layer and a high-brightness aluminum paste. Moreover, the packaging material is excellent in safety even when used in a microwave oven, and can be used to form various packaging containers having a high-class appearance due to metallic luster.
Moreover, according to the manufacturing method of this invention, the said packaging material can be manufactured simply.

1 is a schematic cross-sectional view showing an example of a laminated structure of a packaging material of the present invention; FIG. FIG. 3 is a schematic cross-sectional view showing another example of the laminated structure of the packaging material of the present invention; FIG. 3 is a schematic cross-sectional view showing another example of the laminated structure of the packaging material of the present invention; It is a sectional view showing an example of a pouch for microwave ovens among packaging containers of the present invention. 1 is a top view showing an example of a lidded container among packaging containers of the present invention. FIG. FIG. 6 is a sectional view along IV-IV in FIG. 5; FIG. 3 is a schematic cross-sectional view showing another example of the laminated structure of the packaging material of the present invention; Fig. 2 is a schematic plan view showing another example of a pouch for microwave ovens among the packaging containers of the present invention. FIG. 9 is a cross-sectional view taken along line XI-XI of FIG. 8;

Hereinafter, the packaging material of the present invention, the method for producing the same, and the packaging container using the packaging material will be described in detail. Note that the notation of a numerical range of "AA to BB" in this specification means "from AA to BB".

[Packaging material]
The packaging material of the present invention comprises at least a plastic film, a glossy print layer and a sealant layer laminated in this order from the outer layer side. The glossy print layer contains a pearl pigment and contains 0.5% by mass or less of carbon black.
By forming the glossy print layer using the pearl pigment in this way, it is possible to create a beautiful appearance with a metallic luster without using a metal layer or a high-brightness aluminum paste.

The pearl pigment is a thin plate-like fine particle having a coating layer made of a high refractive index material such as titanium dioxide on the surface of scale-like fine particles of mica, and has light transmittance. Therefore, by arranging the thin plate-like fine particles in a layered manner, light is reflected multiple times, and a metallic or pearl-like luster can be produced.
As described above, pearl pigments are mainly composed of metal oxides rather than metals themselves, but they are coloring agents capable of producing a feeling of metallic luster.

Although there are several types of pearl pigments, they can be roughly classified into three types: white pearl pigments, interference pearl pigments, and colored pearl pigments.
The white pearl pigment has a coating layer of mica made of a colorless high refractive index material such as titanium dioxide, and the coating layer has a relatively small thickness of about 0.1 to 0.15 μm, and can be used for almost all wavelengths of light. appear white or silver.
The interference pearl pigment has a coating layer of mica made of a colorless high refractive index material such as titanium dioxide, and the thickness of the coating layer is greater than that of the white pearl pigment, exceeding 0.15 μm. This thickness changes the reflected and transmitted light, resulting in different interference colors. It is sometimes called an iris colored pearl.
The colored pearl pigment is a chromatic color, and the mica coating layer is made of a colored high refractive index material such as ferric oxide, the white pearl pigment is further surrounded by a colored high refractive index material such as ferric oxide, or other or coated with a colored pigment, or in which a pigment or other coloring agent is added to the mica coating layer.

The pearl pigment used in the present invention may be of any of the types described above. However, from the viewpoint of obtaining a pearl paint color that has a higher brightness and imparts a sense of luxury when viewed from all directions, white pearl pigments and interference pearl pigments are preferred. It is preferable that one or more selected from pigments and one or more selected from colored pearl pigments are included. At least one selected from white pearl pigments and interference pearl pigments is preferably a white pearl pigment, and at least one selected from colored pearl pigments is a coating layer of mica with a color such as ferric oxide. A high refractive index material and a white pearl pigment coated with a colored high refractive index material are preferred.
In this case, in particular, in order to obtain a feeling of deep golden luster when viewed from all directions, as the colored pearl pigment, a coating layer of colored pearl pigment or mica in which the periphery of a white pearl pigment is coated with ferric oxide is used. is ferric oxide, and it is more preferable to use a white pearl pigment as one or more selected from white pearl pigments and interference pearl pigments.

When one or more selected from white pearl pigments and interference pearl pigments (A) and one or more selected from colored pearl pigments (B) are used in combination, the mass ratio of A:B is 1. : 0.2 to 1:20, more preferably 1:0.5 to 1:15, still more preferably 1:1 to 1:10.

The particle size of the pearl pigment is not particularly limited, and the average particle size is preferably 5 to 60 μm, more preferably 5 to 30 μm. In addition, the average particle size in this specification refers to the average particle size of the major axis of arbitrary 20 particles observed with an optical microscope.

The content of the pearl pigment in the glossy print layer is preferably 30 to 90% by mass, more preferably 50 to 85% by mass, and still more preferably 60 to 80% by mass of the total solid content of the glossy print layer. .

The glossy print layer contains 0.5% by mass or less of carbon black as a coloring component. The content of carbon black is preferably 0.1% by mass or less, more preferably 0.01% by mass or less. The black color of carbon black is jet black, and the addition of a small amount of carbon black suppresses the complementary color transmitted through the pearl pigment from reflecting on the inner layer side of the glossy print layer, so that a deep pearl coating color can be obtained. If the amount of carbon black contained in the glossy print layer exceeds 0.5% by mass, the blackness will be too strong, making it difficult to obtain a luxurious chromatic pearl coating color. Further, if the carbon black content is 0.5% by mass or less, when the packaging material is for a microwave oven, the portion where the carbon black is present is locally heated by the microwaves of the microwave oven. It is possible to suppress the opening of holes in the packaging material. The lower limit of the carbon black content in the glossy print layer is preferably 0.0001% by mass or more from the viewpoint of easily obtaining a deep pearl coating color.
Carbon black may be contained as a colorant component of the colored pearl pigment, but is preferably contained as a solid content in the glossy print layer separately from the pearl pigment.
Coloring components other than the pearl pigment contained in the glossy print layer reduce the brightness, so the content of the coloring component other than the pearl pigment in the glossy print layer is 0.5% by mass or less. preferable.

Although the method for forming the glossy print layer containing the pearl pigment is not particularly limited, it can usually be formed with an ink containing the pearl pigment by the printing method for the print layer described below. The ink contains a vehicle comprising a binder resin and a solvent in addition to the pearl pigment.

As the solvent, solvents used in ordinary pigment inks can be applied. Examples include alcohol solvents such as methanol, ethanol, normal propanol, isopropanol, and propylene glycol monomethyl ether, and ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. ester solvents such as methyl acetate, ethyl acetate, and normal propyl acetate; aliphatic hydrocarbon solvents such as normal hexane, normal heptane, and normal octane; and alicyclic hydrocarbon solvents such as cyclohexane, methylcyclohexane, and cycloheptane. Examples include solvents, aromatic solvents such as toluene and xylene, and mineral spirits. These may be used individually by 1 type, or may use 2 or more types together.
Among these, from the viewpoint of the working environment during printing, food hygiene, etc., it is preferable not to contain aromatic solvents.

In general, aluminum paste contains mineral spirit as a solvent. Mineral spirit has a high boiling point of 162 to 192 ° C. at 1 atmosphere, and even when heat drying is performed after printing, It is difficult to completely volatilize and remove, and even a small residual amount may cause the manufactured packaging material to have a solvent odor. It is not desirable for the packaging material to generate such a solvent odor, and particularly when the object to be packaged in the packaging material is food, it is required to suppress the solvent odor as much as possible.
For this reason, it is not preferable to use a solvent with a high boiling point such as mineral spirit as the solvent used for the ink containing the pearl pigment. 120° C. or less, more preferably 120° C. or less.

As described above, the packaging material can be safely used even in a microwave oven because the printed layer does not contain a metal layer or a high-brightness aluminum paste or the like. That is, it can be suitably used for microwave ovens.

(Laminate structure)
1 to 3 show an outline of the laminated structure in the thickness direction of the packaging material of the present invention. 1 to 3, the upper side is the outer layer side and the lower side is the inner layer side. The packaging material 1 may include at least the plastic film 2, the glossy print layer 3a, and the sealant layer 4, which are laminated in this order from the outer layer side, and may include other layers as constituent layers.
For example, as shown in FIGS. 1 to 3, an intermediate substrate layer 5 may be laminated between the glossy print layer 3a and the sealant layer 4 with an adhesive layer 6 interposed on both sides. Further, as shown in FIG. 2, the pattern printed layer 3b may be provided on the outer layer side of the glossy printed layer 3a, and as shown in FIG. You may have Further, as shown in FIG. 3, a white base color printed layer 3d may be provided on the inner layer side of the glossy printed layer 3a. Although not shown, the inner layer side of the glossy print layer 3a in FIG. 1 or 2 may have a white ground color print layer 3d.
A gas barrier layer (not shown) may be formed between the plastic film 2 and the glossy print layer 3 a and between the glossy print layer 3 a and the sealant layer 4 .

Specifically, the following laminated structures can be exemplified in order from the outer layer side. In addition, "/" means the boundary of each layer.
(1) Plastic film/glossy print layer/intermediate substrate layer/sealant layer (2) Plastic film/gas barrier layer/glossy print layer/sealant layer (3) Plastic film/gas barrier layer/glossy print layer/intermediate substrate layer/ Sealant layer (4) Plastic film/glossy print layer/gas barrier layer/intermediate substrate layer/sealant layer From the viewpoint of making the glossy print layer 3a visible from the outside, it is formed on the outer layer side of the glossy print layer 3a. The layer shall be optically transparent.
Each layer will be described below.

<Plastic film>
The plastic film 2 plays a role as a base material on the outer layer side of the packaging material 1, and is made of a material having optical transparency so that the glossy printed layer 3a can be visually recognized from the outside.
Specifically, for example, polyolefin resins such as polyethylene (PE) and polypropylene (PP), cyclic polyolefin resins, polystyrene resins, acrylonitrile-styrene copolymer (AS) resins, acrylonitrile-butadiene-styrene copolymers Polymer (ABS) resin, poly(meth)acrylic resin, polycarbonate resin, polyvinyl alcohol resin, ethylene-vinyl alcohol copolymer (EVOH), saponified ethylene-vinyl ester copolymer, polyethylene terephthalate (PET) Polybutylene terephthalate (PBT), polyester resins such as polyethylene naphthalate (PEN), polyamide resins such as nylon (Ny), polyurethane resins, acetal resins, cellulose resins, polyvinylidene chloride resins (PVDC ) and the like. Among these, polyolefin-based resins are preferred from the viewpoint of versatility, and polyester-based resins and polyamide-based resins are preferred from the viewpoint of heat resistance, strength, and the like.
The plastic film may be uniaxially or biaxially oriented. Also, a composite film in which two or more of the above resin films are laminated may be used.

When the packaging material is used as a microwave oven or a retort container, the plastic film preferably has excellent heat resistance. Polyester-based resins, polyamide-based resins, and the like are examples of resins that constitute plastic films having excellent heat resistance.
Specific examples of plastic films for packaging materials for microwave ovens and retort containers include single polyester films, single polyamide films such as nylon, and composite films containing one or more of polyester films and polyamide films. Examples of the composite film include a coextruded stretched film composed of PET/Ny/PET and PET/Ny from the outer layer side. As the composite film, it is also preferable to combine one or more of polyester film and polyamide film with one or more of ethylene-vinyl alcohol copolymer film and polyvinylidene chloride film.

The thickness of the plastic film 2 is not particularly limited, and can be appropriately set according to the use of the packaging material 1. Generally, it is preferably about 5 to 50 μm, more preferably 10 to 40 μm. More preferably, it is 12 to 25 μm.

<Glossy print layer>
The packaging material of the present invention has a glossy printed layer 3a containing a pearl pigment between the plastic film 2 and the sealant layer 4. As shown in FIG. This glossy print layer 3a creates a beautiful appearance with metallic luster.
The glossy print layer 3a may be formed over the entire surface of the packaging material 1 as shown in FIG. may have been Further, as shown in FIG. 2, the glossy printed layer 3a formed over the entire surface of the packaging material 1 may have a pattern printed layer 3b on a part of the outer layer side. Moreover, as shown in FIG. 3, the packaging material 1 may have a glossy printed layer 3a and a pattern printed layer 3b arranged side by side in the same plane.
Also, pictures such as letters, figures, symbols, designs, and patterns may be formed on the glossy print layer 3a.

The thickness of the glossy print layer 3a is preferably 1 to 10 μm, more preferably 1.5 to 5 μm, from the viewpoint of giving a sufficient impression of metallic luster.

The glossy print layer 3a, and the picture print layer 3b and the white ground color print layer 3d (hereinafter collectively referred to as the "print layer"), which will be described later, are, for example, the plastic film 2, the sealant layer 4, and the like. can be formed thereon by a known printing method such as a gravure printing method, an offset printing method, a letterpress printing method, a silk screen printing method, or the like, using a known ink.
The printed layer is preferably formed by reverse printing on the inner layer side surface of the plastic film 2 or the gas barrier layer. Alternatively, it may be formed by surface printing on the surface of the outer layer side of the intermediate substrate layer 5 or the sealant layer 4 and then bonding it to the plastic film 2 or the gas barrier layer via an adhesive layer. good. Further, the packaging material 1 may be printed entirely or partially.

The ink for the printing layer is usually mainly composed of a vehicle composed of a binder resin and a solvent, and a coloring agent such as a dye or a pigment is added and mixed (the glossy printing layer 3a uses the above-described pearl pigment as an essential ingredient). The colorants for the printed layer may be used singly or in combination of two or more.
Examples of the vehicle include polyolefin resins such as polyethylene resins and chlorinated polypropylene resins, poly(meth)acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate copolymers, Polystyrene resin, styrene-butadiene copolymer, vinylidene fluoride resin, polyvinyl alcohol resin, polyvinyl acetal resin, polyvinyl butyral resin, polybutadiene resin, polyester resin, polyamide resin, alkyd resin, epoxy resin Resins, unsaturated polyester resins, thermosetting poly(meth)acrylic resins, melamine resins, urea resins, polyurethane resins, phenolic resins, xylene resins, maleic acid resins, nitrocellulose, ethyl cellulose, acetylbutyl Fiber resins such as cellulose and ethyloxyethyl cellulose, rubber resins such as chlorinated rubber and cyclized rubber, petroleum resins, natural resins such as rosin and casein, oils and fats such as linseed oil and soybean oil, and solvents mentioned. These may be used singly or in combination of two or more. As the solvent, it is preferable to use the same solvent as that used for the ink containing the pearl pigment described above.
Furthermore, if necessary, for example, light stabilizers such as fillers, stabilizers, plasticizers, antioxidants, ultraviolet absorbers, dispersants, thickeners, desiccants, lubricants, antistatic agents, cross-linking agents, etc. can be added.

<Pattern printing layer>
The packaging material of the present invention may have a pattern printed layer 3b between the plastic film 2 and the sealant layer 4. FIG. The pattern printed layer 3b can be formed, for example, on the outer layer side of the glossy printed layer 3a (Fig. 2), or can be formed in parallel with the glossy printed layer 3a in the same plane of the packaging material 1 (Fig. 3).

The pattern printed layer 3b may be a printed layer formed with a color distinguishable from the gloss printed layer 3a, and is a broad concept including, for example, letters, figures, symbols, designs, patterns, solid printing, and the like. As a coloring agent for the pattern printed layer 3b, general-purpose dyes and pigments (for example, inorganic pigments such as yellow lead, titanium yellow, red iron oxide, cadmium red, ultramarine, cobalt blue, quinacridone red, isoindolinone yellow, phthalocyanine blue, etc. organic pigments) can be used.
The thickness of the pattern printed layer 3b is not particularly limited, and is preferably about 1.5 to 5 μm, more preferably 1.5 to 3 μm.

<White base color printing layer>
As shown in FIG. 3, the packaging material of the present invention preferably has a white base color printed layer 3d on the inner layer side of the glossy printed layer 3a. By forming the white ground color printed layer 3d, the appearance of the packaged item can be improved depending on the type of the packaged item.
When such a white ground color print layer 3d is provided in contact with the inner layer side of the glossy print layer 3a, usually, the transmitted light of the pearl pigment (complementary color of the reflected light of the pearl pigment) is reflected by the white ground color print layer 3d. In the present invention, since the gloss print layer 3a contains a small amount of carbon black, the reflection of the light transmitted through the pearl pigment by the white base color print layer 3d is suppressed. It is possible to achieve both the metallic luster of the packaging material 1 and the appearance when viewed from the inner layer side.
The white ground color printed layer 3d may be formed only on a part of the surface of the packaging material. It is preferable to form it over the entire surface of the packaging material 1 . The white ground color printed layer 3d is preferably formed by single-color solid printing.

A general-purpose white pigment can be used as a coloring agent for the white base color printed layer 3d. In addition, in order to adjust the color of the white base color printed layer 3d, a dye or pigment other than the white pigment may be used as the coloring agent.
The thickness of the white ground color printed layer 3d is not particularly limited, and is preferably about 1.5 to 5 μm, more preferably 1.5 to 3 μm.

<Sealant layer>
The surface of the sealant layer 4 on the inner layer side comes into direct contact with the object to be packaged, and plays a role of protecting the object to be packaged. In particular, when the packaging material 1 forms a packaging container for a liquid, it is preferably made of a material that does not allow the liquid to permeate. It preferably has heat sealability.

Examples of materials constituting the sealant layer 4 include low-density PE (LDPE), linear low-density PE (LLDPE), medium-density PE (MDPE), high-density PE (HDPE), and ethylene-vinyl acetate copolymer. , PP homopolymers, ethylene-propylene block copolymers, ethylene-propylene block copolymers and other polyolefin resins, and the like, and one or more of these resins can be used. The sealant layer 4 may be composed of a single layer or multiple layers of two or more layers. From the viewpoint of suppressing shrinkage during heat sealing, the sealant layer 4 is preferably a non-stretched film made of the resin described above.

When the packaging material is used as a microwave oven or a retort container, the sealant layer is preferably made of a resin having excellent heat resistance. Specifically, PP homopolymer, ethylene-propylene block copolymer, ethylene-propylene. PP-based resins such as random copolymers are preferred.
It is preferable to use the PP-based resin properly depending on the purpose. Specifically, when emphasizing cold resistance (for example, packaging materials for frozen foods), ethylene-propylene block copolymers are preferable, and when emphasizing transparency, ethylene-propylene random copolymers A coalescence is preferable, and a PP homopolymer is preferable when heat resistance is emphasized. Further, in the case of a container equipped with an automatic vaporization mechanism, an ethylene-propylene block copolymer is preferable from the viewpoint of facilitating the escape of vapor due to a decrease in sealing strength at high temperatures.

Moreover, when the lid of a lidded container is formed from the packaging material 1, the sealant layer 4 preferably has an easy peel property. For example, when the sealant layer 4 of the packaging material 1 of the lid of the lidded container is joined to the container body, the lid is easily peeled off from the container body when the lidded container is opened. say characteristics. The sealant layer having easy peelability uses two or more resins, one resin (resin having good adhesion to the container body) and another resin (not having good adhesion to the container body). It can be formed by mixing one resin and an incompatible resin). Such a resin varies depending on the material of the container, so it cannot be generalized. , Another resin (a resin that does not have good adhesion to the container body and is incompatible with the first resin) PE, polybutene, and polystyrene. Form a sealant layer from a resin mixed with one or more. By doing so, easy peelability can be imparted to the PP container.
The sealant layer 4 may have a multi-layer structure, and the easy peel property may be imparted only to the side of the sealant layer 4 that is joined to the container body (the innermost layer in the packaging material).

The thickness of the sealant layer 4 is not particularly limited, and is appropriately set according to the use of the packaging material 1 and the type and properties of the object to be packaged, but it is usually preferably about 10 to 200 μm. In the case of pouches (especially retort pouches), the thickness of sealant layer 4 is more preferably 20 to 150 μm, and even more preferably 30 to 100 μm. In the case of a container with a lid, the thickness of the sealant layer 4 is more preferably 15-80 μm, more preferably 20-60 μm.

<Gas barrier layer>
A gas barrier layer can be provided between the plastic film 2 and the sealant layer 4, if necessary. The gas barrier layer plays a role of blocking permeation of oxygen, water vapor, and the like between an object to be packaged by the packaging material 1 and the external environment of the packaging material 1 . In addition, it may also have a light-shielding property that blocks the transmission of visible light, ultraviolet rays, and the like. The gas barrier layer may be composed of only one layer, or may be composed of two or more layers.
When the gas barrier layer is formed on the outer layer side of the glossy print layer 3a, like the plastic film 2, it is made of a material having optical transparency so that the glossy print layer 3a can be visually recognized from the outside.

The gas barrier layer can be formed as a vapor deposition film or a coating film by a known method. The surface on which the gas barrier layer is to be formed may be previously surface-treated from the viewpoint of improving the adhesion of the gas barrier layer. Examples of the surface treatment include corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas, nitrogen gas, glow discharge treatment, oxidant treatment, application of an anchor coating agent, and the like.

[Deposition film]
Examples of vapor deposition films that are examples of gas barrier layers include silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron ( B), inorganic substances such as titanium (Ti), lead (Pb), zirconium (Zr), yttrium (Y), or oxides thereof. Among these, when the packaging material is for a microwave oven, silicon oxide, aluminum oxide, magnesium oxide, etc. are used from the viewpoint of enabling the food to be packaged to be sufficiently heated by the microwave of the microwave oven. is preferred.
Examples of methods for forming a deposited film include physical vapor deposition (PVD) methods such as vacuum deposition, sputtering, and ion plating, and chemical vapor deposition (CVD) methods such as plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition. law, etc.

The film thickness of the deposited film varies depending on the forming material, the required gas barrier performance, etc., but is generally preferably about 5 to 200 nm, more preferably 5 to 150 nm, further preferably 10 to 100 nm. In the case of inorganic oxides such as silicon oxides and aluminum oxides, the thickness is preferably about 5 to 100 nm, more preferably 5 to 50 nm, still more preferably 10 to 30 nm.

[Gas barrier coating film]
^A gas barrier _coating film, which is an example of ^a _gas ^barrier layer, may be represented by the general ^formula : n is an integer of 0 or more, m is an integer of 1 or more, and n+m is the valence of M.) and at least one or more alkoxides represented by ), a polyvinyl alcohol resin and/or ethylene-vinyl A coating solution obtained by polycondensing an alcohol copolymer by a sol-gel method in the presence of a sol-gel method catalyst, acid, water and an organic solvent is applied, and the temperature is reduced to 0 at 50 to 300 ° C. It can be formed by heat treatment for 0.05 to 60 minutes.
Examples of the coating method include roll coating such as a gravure roll coater, spray coating, spin coating, dipping, brush coating, bar coating, and coating means such as an applicator. It is preferable that the dry film thickness of the coated film is about 0.01 to 30 μm, more preferably 0.05 to 20 μm, and still more preferably 0.1 to 10 μm by coating once or multiple times.
From the viewpoint of improving gas barrier properties, the gas barrier coating film is preferably formed on the surface of the deposited film.

Considering the specific structure of the gas barrier layer, the packaging material of the present invention can be exemplified by the following lamination structures (1′) to (4′) in order from the outer layer side. In addition, "/" means the boundary of each layer.
(1′) Plastic film/deposited film/glossy print layer/sealant layer (2′) Plastic film/deposited film/gas barrier coating film/glossy print layer/sealant layer (3′) Plastic film/glossy print layer/deposited film /Intermediate substrate layer/sealant layer (4') plastic film/glossy print layer/gas barrier coating film/deposited film/intermediate substrate layer/sealant layer

<Intermediate base material layer>
The intermediate base material layer 5 is necessary for the purpose of improving the strength of the packaging material 1, improving the processability, changing the texture of the packaging material, or using it as a base material for forming other layers. It is a layer provided accordingly. Examples of the constituent material of the intermediate base material layer include plastic films and paper.
In the case of a plastic film, the same one as the plastic film 2 described above formed on the outer layer side of the glossy print layer 3a can be used.
In the case of paper, the packaging material 1 can be imparted with properties such as formability, bending resistance, and rigidity. processed paper or the like can be used. The basis weight of the paper is preferably about 50-600 g/m ² , more preferably 60-500 g/m ² , still more preferably 70-450 g/m ² . When the packaging material 1 is used for flexible packaging, it is preferably less than 150 g/m ² , and when used for paper containers such as paper cups and paper containers for liquids, it is preferably 200 g/m ² or more.

When the packaging material 1 is used as a microwave oven or a retort container, the intermediate base material layer 5 preferably has excellent heat resistance. Specific examples of the intermediate base material layer 5 having excellent heat resistance include the plastic film exemplified as the plastic film 2 of the packaging material for microwave ovens and retort containers, and paper.

<Adhesive layer>
In the packaging material 1, each component layer may be laminated via an adhesive layer 6 from the viewpoint of improving the bonding strength between the layers. The adhesive layer 6 can be formed by a method using a known adhesive for dry lamination.
Examples of dry laminate adhesives include polyvinyl acetate adhesives, polyacrylate adhesives, cyanoacrylate adhesives, ethylene copolymer adhesives, cellulose adhesives, polyester adhesives, and polyamide adhesives. Adhesives, polyimide adhesives, amino resin adhesives such as urea resins and melamine resins, phenol resin adhesives, epoxy adhesives, polyurethane adhesives (for example, cured products of polyols and isocyanate compounds), reactions Examples include (meth)acrylic acid-based adhesives, rubber-based adhesives such as chloroprene rubber, nitrile rubber, and styrene-butadiene rubber, silicone-based adhesives, and inorganic adhesives such as alkali metal silicate and low-melting glass.

<Thermosoftening resin layer>
The packaging material 1 may have a heat-softening resin layer 7 in a partial region between the plastic film 2 and the sealant layer 4, as shown in FIG.
As shown in FIG. 7, the thermosoftening resin layer 7 is formed in a part near the edge of the packaging material 1, and the thermosoftening resin layer 7 has a predetermined strength in a temperature environment below room temperature. However, since it is made of a resin whose strength decreases in a high temperature environment, when it is heated in a microwave oven and the pressure inside the packaging container increases, part of the sealant layer 4 is destroyed and the heat softening resin A portion of layer 7 may interfacially delaminate or cohesively fail, allowing vapor to escape. Details will be described in a second embodiment of the automatic vaporization mechanism, which will be described later.

As the thermosoftening resin 7, that is, a resin that has a predetermined strength in a temperature environment below room temperature but whose strength decreases in a high temperature environment, a resin with a melting point of 60 to 110°C, preferably 60 to 90°C is used. mentioned. Specific examples thereof include ethylene-vinyl acetate copolymer resin, polyamide, nitrocellulose and polyethylene wax, and a mixed resin of polyamide, nitrocellulose and polyethylene wax is preferred. As the resin containing polyamide, nitrocellulose and polyethylene wax, MWOP varnish (softening point: 105° C.) manufactured by DIC Graphics Corporation can be used.

The thickness of the thermosoftening resin layer 7 is preferably 1 to 5 μm. By setting the thickness of the thermosoftening resin layer 7 to 1 μm or more, the thermosoftening resin layer 7 and the sealant layer 4 can be easily destroyed when heated in a microwave oven. In addition, by setting the thickness of the thermosoftening resin layer 7 to 5 μm or less, it is possible to suppress the expansion of a part of the packaging material caused by swelling when the film-like packaging material is wound into a roll.

[Packaging container]
At least a part of the packaging container of the present invention is formed of the packaging material.
By using the packaging material described above, a packaging container with a high-class appearance due to its metallic luster can be obtained without using metal itself.
The packaging material may be applied to a desired portion where it is desired to impart a high-class feeling with metallic luster. may
In addition, when the packaging material is heat-sealed, the packaging material with the metallic luster layer formed by the high-brightness aluminum paste is not suitable for microwave ovens because the aluminum particles in the high-brightness aluminum paste are close to each other when heat-sealed. In the packaging material of (1), the risk of sparks caused by microwaves in the microwave oven increases. In contrast, the packaging material of the present invention does not cause such a risk even when heat-sealed.

The type and use of the packaging container of the present invention are not particularly limited, but when selling the contents housed in the packaging container, it is possible to impress the purchaser with the high-class feeling of the contents. For example, it can be suitably used for food containers, cosmetic containers, and the like.
Examples of the shape of the packaging container include pouches and containers with lids, as well as cups and trays. These packaging containers partially contain the packaging material. That is, the packaging container may be formed of a packaging material containing paper as the intermediate base material layer 5 .
A specific shape of the pouch is, for example, the shape of a pouch for a microwave oven as shown in FIG. 5, which will be described later. The pouch may be a retort container (a container sterilized at high temperature and high pressure), or may be a packaging container for a microwave oven or a container other than a retort container.
Further, as a specific shape of the container with a lid, it has a configuration including a container body having an accommodating portion and a lid joined to the container body so as to seal the accommodating portion. is formed of the packaging material.
The packaging container can be suitably used for a microwave oven. The packaging container can also be used as a retort container.

When the packaging container is a container for a microwave oven or a retort container, the packaging material constituting the container preferably has a laminated structure of any one of (1) to (4) described above.
In this case, as the plastic film 2, it is preferable to use a single polyester film, a single polyamide film such as nylon, or a composite film containing at least one of a polyester film and a polyamide film.
In this case, as the intermediate base material layer 5, any one of a single polyester film, a single polyamide film such as nylon, a composite film containing one or more of a polyester film and a polyamide film, and paper may be used. is preferred.
In this case, the sealant layer 4 is preferably made of PP-based resin such as propylene homopolymer, ethylene-propylene block copolymer, ethylene-propylene random copolymer, or HDPE.

More specifically, in the case of a microwave oven or a retort container, the packaging material constituting the packaging container preferably has any one of the following laminated structures (A1) to (A12). In addition, "/" means the boundary of each layer. In (A1) to (A12), PET and Ny are preferably stretched films.
(A1) PET/glossy print layer/Ny/ethylene-propylene block copolymer (A2) PET/gas barrier layer/glossy print layer/Ny/ethylene-propylene block copolymer (A3) PET/glossy print layer/gas barrier layer /Ny/ethylene-propylene block copolymer (A4) PET/glossy print layer/PET/ethylene-propylene block copolymer (A5) PET/gas barrier layer/glossy print layer/PET/ethylene-propylene block copolymer ( A6) PET/glossy print layer/gas barrier layer/PET/ethylene-propylene block copolymer (A7) Coextruded stretched film (PET/Ny/PET) PET/glossy print layer/PET/ethylene-propylene block copolymer ( A8) Coextruded stretched film (PET/Ny/PET)/gas barrier layer/glossy print layer/PET/ethylene-propylene block copolymer (A9) Coextruded stretched film (PET/Ny/PET)/glossy print layer/gas barrier Layer/PET/ethylene-propylene block copolymer (A10) PBT/glossy print layer/Ny/ethylene-propylene block copolymer (A11) PBT/gas barrier layer/glossy print layer/Ny/ethylene-propylene block copolymer (A12) PBT/glossy print layer/gas barrier layer/Ny/ethylene-propylene block copolymer

In the case of packaging containers for microwave ovens, the ethylene-propylene block copolymer, which is the sealant layer (A1) to (A12), may be a polyethylene-based resin such as LDPE, LLDPE, MDPE, and HDPE.
In addition, in the packaging container for microwave ovens, when adopting the configuration of the automatic vaporization mechanism of the second embodiment described later, a part between the plastic film 2 and the sealant layer 4 is the above-described thermosoftening resin Layer 7 may be formed.

(pouch)
FIG. 4 shows an example of a pouch for microwave ovens, which is an embodiment of the packaging container of the present invention. The pouch 10 shown in FIG. 4 is a standing-type microwave oven pouch formed by heat-sealing a body portion 11 and a bottom portion 12 . As shown in FIG. 4, the body portion 11 includes a pair of main sheets 13 composed of a front main sheet 13a and a back main sheet 13b, which are arranged to face each other. The sheets 13 are heat-sealed to each other near the side edges 14 . A bottom sheet 16 forming the bottom 12 is arranged between the lower edges 15 of the pair of main sheets 13 .
A storage space 17 for storing contents is formed in a region surrounded by the pair of main sheet 13 and bottom sheet 16 . The bottom sheet 16 is bent in a convex shape toward the accommodation space 17 side, and the vicinity of the peripheral edge thereof is heat-sealed together with the overlapping lower part of the main sheet 13 . Since the bottom sheet 16 retains the shape of the lower ends of the pair of main sheets 13, the pouch 10 can be made self-supporting and can be a standing pouch.
The pouch 10 has an opening 19 formed between the upper edges 18 of the front main sheet 13a and the back main sheet 13b, and contents can be stored through the opening 19. As shown in FIG. After containing the contents, the vicinity of the upper edge 18 where the opening 19 is formed can be heat-sealed for sealing. When taking out the contents from the pouch 10, it is opened by tearing the vicinity of the upper edge 18 from the notch 23. - 特許庁

The front main sheet 13 a , back main sheet 13 b and bottom sheet 16 of the pouch 10 can be formed from the packaging material 1 . All of these sheets may be formed of the packaging material 1 having the glossy print layer 3a containing the pearl pigment, or only one of the sheets requiring metallic luster may be formed of the packaging material 1. good. FIG. 5 shows that the front main sheet 13a is formed so as to have a glossy print layer 3a and a pattern print layer 3b in the packaging material 1 having a laminated structure as shown in FIG.
Sheets other than the sheet for which the packaging material 1 is used may be, for example, the packaging material 1 in which the glossy printed layer 3a containing the pearl pigment is not formed, or the printed layer is not included.

<Automatic steaming mechanism>
If the packaging container is for a microwave oven, when the pressure inside the pouch rises due to the steam generated by cooking the contents such as food, the steam inside the containing space will automatically escape to the outside, causing the pouch to burst. It is preferable to have an automatic vaporization mechanism to prevent The automatic steaming mechanism is preferably formed near the periphery of the container.

A first embodiment of the automatic steaming mechanism will be described with reference to FIG. The microwave pouch 10 shown in FIG. 4 has a first unsealed region 21 that is not heat-sealed near the upper side edge 14 of the pouch. The first unsealed area 21 has an opening 22 down to the side edge 14 . Also, the first unsealed area 21 protrudes toward the housing space 17 . Further, the heat-sealed portion 25 protrudes toward the housing space 17 so as to surround the first unsealed region 21 that protrudes toward the housing space 17, forming a projecting portion 25a. More specifically, the first unsealed region 21 and the accommodation space 17 are separated from each other, and an overhanging portion 25a is formed so as to be continuous with the heat-sealing portion 25 that seals the pouch.
The pouch 10 for microwave oven shown in FIG. formed. Specifically, when the pressure inside the container rises due to heating, the protrusion 25a of the heat-sealed portion 25 receives a strong load and peels off first. It communicates with the seal area 21 to allow steam to escape to the outside.
Further details of the automatic vaporization mechanism of the form as shown in FIG.

In the pouch 10 shown in FIG. 4, a second unsealed area 23 is formed on the side edge 14 opposite to the first unsealed area 21 . The second unsealed area 23 is formed from the viewpoint of improving the yield of forming the openings 22 of the first unsealed area 21 when cutting the pouches 10 one by one after forming the pouches 10 continuously. and does not necessarily have to be formed.

A second embodiment of the automatic vaporization mechanism will be described with reference to FIGS. 7-9.
The pouch 10 shown in FIG. 8 is the edge portion of the packaging material shown in FIG. The periphery is heat-sealed to form a pouch. 9 is a cross-sectional view of the heat-sealed portion 25 around the edge of the pouch 10 of FIG. 8 taken along line XI-XI.
As shown in FIG. 8, the thermosoftening resin layer 7 is formed over at least a part of the heat-sealed portion 25 of the pouch 10 from the inner edge to the outer edge of the heat-sealed portion 25 that seals the pouch. become necessary. The strength of the thermosoftening resin layer 7 provided at such a position is lowered by being heated in a microwave oven to a high temperature.
As shown in FIG. 9, in the heat-sealed portion 25 of the pouch 10, the thermosoftening resin layer 7 is heated in a microwave oven or the like, and the internal pressure is increased by the expansion of the air in the packaging container 10 and the steam generated from the contents. When it rises, part of the sealant layer 4 breaks, and part of the heat-softening resin layer 7 undergoes interfacial peeling or cohesive failure starting from an arbitrary point A of the sealant layer 4 near the inner edge of the heat-sealed portion 25 as a starting point. (A broken line B indicates an imaginary line where the sealant layer 4 breaks and the thermosoftening resin layer 7 undergoes interfacial peeling or cohesive failure.). As a result, air or steam escapes from the broken portion, and the internal pressure of the pouch 10 can be reduced without causing the contents to scatter.
Note that the automatic steaming mechanism of the second embodiment can also be applied to a container with a lid, which will be described later.

As the packaging material that constitutes the container having the second embodiment of the automatic steaming mechanism, it is preferable to select a resin that easily collapses as the resin that constitutes the sealant layer. Specifically, LLDPE is preferred. Moreover, the packaging material constituting the container equipped with the second embodiment of the automatic steaming mechanism preferably has any one of the following laminated structures (B1) to (B6). In addition, "/" means the boundary of each layer. In (B1) to (B6), PET and Ny are preferably stretched films.
(B1) PET/glossy print layer/thermosoftening resin layer/LLDPE
(B2) PET/gas barrier layer/glossy print layer/thermosoftening resin layer/LLDPE
(B3) PET/glossy print layer/gas barrier layer/thermosoftening resin layer/LLDPE
(B4) Ny/glossy print layer/thermosoftening resin layer/LLDPE
(B5) Ny/gas barrier layer/glossy print layer/thermosoftening resin layer/LLDPE
(B6) Ny/glossy print layer/gas barrier layer/thermosoftening resin layer/LLDPE

(Container with lid)
5 and 6 show an example of an embodiment of the lidded container of the present invention. 5 is a top view, and FIG. 6 is a cross-sectional view taken along line IV--IV of FIG. A lidded container 30 shown in FIGS. 5 and 6 includes a container body 32 having an accommodating portion 31 formed therein, and a lid body 33 joined to the container main body 32 so as to seal the accommodating portion 31 of the container body 32. ing. In FIG. 5, the shape of the container body 32 is substantially rectangular, but is not particularly limited. The container body 32 is not particularly limited in its molding method, and may be, for example, a tray molded by injection molding or a container formed by deep drawing.
In addition, since the material of the container body 32 is to be joined to the lid 33, it is usually thermoplastic resin such as PP or PET. From the viewpoint of heat resistance and the like, PP is preferably used.

It is preferable that the lid 33 of the lidded container 30 is formed of the packaging material 1 . According to such a lid 30, the packaging material 1 having the glossy print layer 3a containing the pearl pigment can give the lidded container 30 a beautiful appearance, and the content contained in the lidded container 30 The appearance of the lidded container 30 can give an impression of luxury of the product. In addition, FIG. 6 shows that the lid 33 is formed so as to have the glossy printed layer 3a and the picture printed layer 3b in the packaging material 1 having a laminated structure as shown in FIG.

The lid 33 has an easy peel property, as described in the description of the sealant layer 4 of the packaging material 1, from the viewpoint of facilitating the opening of the lidded container 30 by being peeled off from the container body 32. is preferred.
Specifically, the lid 33 and the container body 32 are joined together at a joint line 35 of the flange portion 34 of the container body 32 . The joining line 35 may be formed, for example, by heat-sealing the lid 33 and the flange portion 34, or may be formed by a separate component such as an adhesive layer.

When the lidded container 30 is used for a microwave oven, when the pressure in the lidded container 30 rises due to the steam generated by cooking the food or the like, which is the content contained in the container body 32, the lidded container 30 is heated. It is preferable to have an automatic vaporization mechanism (third embodiment of the automatic vaporization mechanism) that automatically releases the steam in the container 30 to the outside to prevent the lidded container 30 from bursting.
For example, the flange portion 34 has a protruding portion 34a that protrudes toward the center of the container body 32, and along this protruding portion 34a, the joint line 35 also protrudes toward the center of the container. It has a line 35a. Since the joint line 35 is formed in such a form, it becomes easier for the joint line 35 to separate from the protruding line 35 a of the joint line 35 as the pressure inside the lidded container 30 increases due to heating. The storage portion 31 can be communicated with the outside, and the steam in the lidded container 30 can be released to the outside.
In the lidded container 30 shown in FIGS. 5 and 6, the projecting portions 34a are formed on the opposite long sides of the flange portion 34, but two projecting portions 34a are not necessarily formed. may

Moreover, as the lid body 33 constituting the lidded container 30, the packaging material shown in FIG. By using the packaging material, steam can escape when heated in a microwave oven for the same reason as explained in the second embodiment of the automatic steaming mechanism.

(Lid body)
The lid of the present invention is formed of the packaging material of the present invention described above.
The packaging material that constitutes the lid preferably has a laminated structure of any one of (1) to (4) described above.
Further, when the lid is used as a microwave oven or a retort container, the plastic film 2 may be a single polyester film, a single polyamide film such as nylon, or a composite film containing at least one of a polyester film and a polyamide film. is preferred.
Further, when the lid is used as a microwave oven or a retort container, the intermediate base material layer 5 may be a single polyester film, a single polyamide film such as nylon, or a composite film containing at least one of a polyester film and a polyamide film. , and paper.
Moreover, when the lid body is used as a microwave oven or a retort container, it is preferable to use a resin film having both heat resistance and easy peelability as the sealant layer 4 . Such a film varies depending on the type of container, but if the container is a general-purpose PP-based resin, it is possible to use a film made of a resin in which PP is mixed with one or more selected from PE, polybutene and polystyrene. preferable. The sealant layer 4 may have a multi-layer structure, and the easy peel property may be imparted only to the side of the sealant layer that is joined to the container body (the innermost layer in the packaging material).

More specifically, the packaging material that constitutes the lid preferably has a laminated structure of any one of the following (C1) to (C11). In addition, "/" means the boundary of each layer. In (C1) to (C11), PET and Ny are preferably stretched films.
(C1) PET/glossy print layer/Ny/easy peelable sealant layer (C2) PET/gas barrier layer/glossy print layer/Ny/easy peelable sealant layer (C3) PET/glossy print layer/ Gas barrier layer/Ny/Easy peel sealant layer (C4) PET/Glossy print layer/PET/Easy peel sealant layer (C5) PET/Gas barrier layer/Glossy print layer/PET/Easy peel Sealant layer provided (C6) PET/glossy print layer/gas barrier layer/PET/sealant layer with easy peelability (C7) Ny/glossy print layer/Ny/sealant layer with easy peelability (C8) Ny/ Gas barrier layer/glossy print layer/Ny/easy peelable sealant layer (C9) Ny/glossy print layer/gas barrier layer/Ny/easy peelable sealant layer (C10) Ny/glossy print layer/EVOH/ Sealant layer with easy peelability (C11) Ny/EVOH/glossy print layer/sealant layer with easy peelability

In addition, when adopting the configuration of the second embodiment of the above-described automatic vaporization mechanism for the lid body, the above-described heat-softening resin layer 7 is formed in a part between the plastic film 2 and the sealant layer 4. Just do it.

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited by these examples.

[Production of packaging material]
(Example 1)
A packaging material sample was prepared in which plastic film/vapor-deposited film/gas barrier coating film/glossy print layer/white base color print layer/adhesive layer/intermediate substrate layer/adhesive layer/sealant layer were laminated in this order from the outer layer side. did. The structure of each layer is as follows.
・Plastic film: PET (thickness 12 μm)
Gas barrier layer: One surface of the plastic film was subjected to corona discharge treatment, and then a silicon oxide deposition film having a thickness of 10 nm was formed. Furthermore, after plasma treatment with a mixed gas of oxygen and argon, a coating solution containing ethyl silicate and polyvinyl alcohol as main components was applied with a gravure roll coater to form a gas barrier coating film with a dry film thickness of 300 nm. did.
Glossy print layer: The following gold ink 1 for glossy print layer was gravure printed on the entire surface of the gas barrier layer and dried to form a glossy print layer having a dry film thickness of 3 μm.
- White base color print layer: Further, a white pigment ink was gravure printed on the entire surface of the glossy print layer and dried to form a white base color print layer having a dry film thickness of 3 µm.
Intermediate base material layer: Stretched Ny (thickness: 15 µm) was attached to the surface of the white background printed layer by a dry lamination method using a polyurethane adhesive.
Sealant layer: A CPP (single-layer film of ethylene-propylene block copolymer, thickness 70 µm) was adhered to the surface of the intermediate substrate layer by a dry lamination method using a polyurethane adhesive.

<Gold ink 1 for glossy print layer>
・White pearl pigment (average particle size 15 μm): 10 parts by mass ・Colored pearl pigment (colored pearl pigment whose mica coating layer is ferric oxide, average particle size 15 μm): 20 parts by mass ・Carbon black: 0.001 Parts by mass ・Anti-settling agent (fine particle silica): 0.1 parts by mass ・Binder resin (polyurethane resin): 10 parts by mass ・Solvent (propylene glycol monomethyl ether, normal propyl acetate, ethyl acetate, isopropanol mixed solvent): 60 part by mass

(Comparative example 1)
In Example 1, a packaging material sample was produced in the same manner as in Example 1 except that the printed layer had the following configuration.
- Print layer: On the surface of the gas barrier layer, the following gold ink 2 for glossy print layer (high-brightness aluminum paste) was gravure-printed and dried to form a glossy print layer having a dry thickness of 3 µm.

<Gold ink 2 for glossy print layer>
・Aluminum flakes: 7 parts by mass ・Organic yellow pigment: 3 parts by mass ・Anti-settling agent (fine particle silica): 2 parts by mass ・Binder resin (polyurethane resin): 20 parts by mass ・Solvent 1 (mineral spirit): 7 parts by mass Part Solvent 2 (propylene glycol monomethyl ether, normal propyl acetate, ethyl acetate, mixed solvent of isopropanol): 70 parts by mass

(Comparative example 2)
A packaging material sample was prepared in the same manner as in Example 1 except that the gold ink 3 for a glossy print layer containing no carbon black was used in the gold ink 1 for a glossy print layer of Example 1.

When the outer layer surface of each packaging material prepared in the above Examples and Comparative Examples was visually observed, the glossy printed layer made of pearl pigment (Example 1) was equivalent to the glossy printed layer made of high-brightness aluminum paste (Comparative Example 1). A golden metallic luster was observed. In addition, when ink 3 for glossy print layer containing no carbon black was used (Comparative Example 2), the glossy print layer did not have metallic luster due to a sufficiently deep gold pearl coating color.
In addition, the packaging material sample of Comparative Example 1 had a slight solvent odor that was considered to be caused by mineral spirits.

[Evaluation of Retort Pouch]
(Example 2)
Using the packaging material sample produced in Example 1, a pouch 10 as shown in FIG. 4 was produced and sealed.

(Comparative Example 3)
Using the packaging material sample produced in Comparative Example 1, a pouch 10 as shown in FIG. 4 was produced and sealed.

Twenty pouches produced in the above Examples and Comparative Examples were retorted at 135° C. for 30 minutes, and then heated in a microwave oven at 600 W for 2 minutes.
As a result, no change was observed in any of the 20 points of the retort pouch of Example 2. On the other hand, with respect to the retort pouches of Comparative Example 3, 7 points out of 20 showed holes at the portion where the glossy print layer was formed.
From this, it can be concluded that the retort pouch made from the packaging material of the present invention can be safely applied to cooking with heat in a microwave oven, etc., even when subjected to high retort pouch processing at 130°C or higher. I can say

REFERENCE SIGNS LIST 1 packaging material 2 plastic film 3a glossy print layer 3b picture print layer 3d white ground color print layer 4 sealant layer 5 intermediate base material layer 6 adhesive layer 7 thermosoftening resin layer 10 pouch 11 trunk section 12 bottom section 13 main surface sheet 14 Side edge 15 Lower edge 16 Bottom sheet 17 Storage space 18 Upper edge 19 Opening 20 Automatic vaporization mechanism 21 First unsealed area 22 Opening 23 Second unsealed area 24 Notch 25 Heat-sealed portion 30 Container with lid 31 Storage portion 32 Container Body 33 Lid 34 Flange 35 Joint line

Claims (10)

A packaging material having a configuration in which at least a plastic film, a glossy print layer and a sealant layer are laminated in this order from the outer layer side,
A packaging material comprising an adhesive layer between the glossy print layer and the sealant layer, wherein the glossy print layer contains a pearl pigment, and 0.0001% by mass or more and 0.01% by mass or less of carbon black. (However, the adhesive layer does not include a decorative pigment containing a pigment having an average particle size of 20 µm or more or a particle size of 40 µm or more). 2. The packaging material according to claim 1, wherein said pearl pigment includes one or more selected from white pearl pigments and interference pearl pigments, and one or more selected from colored pearl pigments. The packaging material according to claim 1 or 2, which is for a microwave oven. In the method for producing the packaging material according to any one of claims 1 to 3,
A method for producing a packaging material, wherein the glossy print layer is formed of an ink containing the pearl pigment, and a solvent contained in the ink has a boiling point of 150° C. or less at 1 atm. A packaging container at least partly formed of the packaging material according to claim 1 or 2. 6. The packaging container according to claim 5, wherein said packaging container is a pouch. A lidded container comprising a container body having an accommodating portion and a lid joined to the container body so as to seal the accommodating portion, wherein the lid is formed of the packaging material. 6. The packaging container according to item 5. The packaging container according to any one of claims 5 to 7, which is for a microwave oven. The packaging container according to any one of claims 5 to 8, which is a retort container. A lid made of the packaging material according to any one of claims 1 to 3.

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