JP7047275B2 - Packaging materials and their manufacturing methods, packaging containers and lids - Google Patents

Description

The present invention relates to a packaging material and a method for producing the same, and a packaging container using the packaging material, particularly a packaging material that can be used in a microwave oven, a method for producing the same, a packaging container, and a lid.

The packaging material may be decorated with a high-brightness metallic luster from the viewpoint of producing a sense of luxury and luxury of the object to be packaged to create an aesthetic appearance. As such a decorative means, for example, forming a metal layer made of a metal vapor 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 have microwaves in the microwave oven when the surface of the packaging material is formed of the above-mentioned metal layer. Is reflected on the surface of the metal layer, causing sparks, which may lead to microwave oven failure or accident, and the contents in the packaging container cannot be sufficiently heated.

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

Japanese Unexamined Patent Publication No. 2017-81589

By the way, some packaging containers such as microwave oven pouches are subjected to retort treatment for pressure heating sterilization after the contents such as foods are stored in the packaging container, and depending on the contents, the temperature is 130 ° C. The above high temperature treatment, so-called high retort treatment, may be performed. A package having a metallic luster layer formed of a high-brightness aluminum paste as described in Patent Document 1 is a high-brightness aluminum paste, especially when it is cooked in a microwave oven after high-retort treatment. It cannot be said that the deterioration is sufficiently suppressed because a hole may be formed in the portion where the metal is used, and it cannot be said that the safety in cooking in a microwave oven is sufficient.

Therefore, among packaging materials that are used in microwave ovens, in order to give an aesthetic appearance due to metallic luster, other than forming the metallic luster layer as described above or the metallic luster layer using high-brightness aluminum paste. Other means are required.

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

According to the present invention, by using a pearl pigment, a packaging material capable of producing an aesthetic appearance due to metallic luster without using a high-brightness aluminum paste can be obtained, and the packaging material can be used even when used in a microwave oven. It is based on the finding that it is excellent in safety.

That is, the present invention provides the following [1] to [11].
[1] A packaging material having a structure in which at least a plastic film, a glossy printing layer, and a sealant layer are laminated from the outer layer side in this order, and the glossy printing layer contains a pearl pigment.
[2] The packaging material according to the above [1], wherein the pearl pigment contains one or more selected from white pearl pigments and interference pearl pigments, and one or more selected from colored pearl pigments.
[3] The packaging material according to the above [1] or [2], wherein a black background color printing layer is provided in contact with the inner layer side of the glossy printing layer.
[4] The packaging material according to any one of the above [1] to [3], which is for a microwave oven.
[5] In the method for producing the packaging material according to any one of the above [1] to [4], the glossy print layer is formed of an ink containing the pearl pigment, and the solvent contained in the ink is used. A method for producing a packaging material, characterized in that the boiling point at 1 atm is 150 ° C. or lower.

[6] A packaging container in which at least a part thereof is made of the packaging material according to any one of the above [1] to [3].
[7] The packaging container according to the above [6], wherein the packaging container is a pouch.
[8] A container with a lid including a container body having an accommodating portion and a lid body joined to the container body so as to seal the accommodating portion, and the lid body is formed of the packaging material. The packaging container according to the above [6].
[9] The packaging container according to any one of the above [6] to [8], which is for a microwave oven.
[10] The packaging container according to any one of the above [6] to [9], which is a retort container.
[11] A lid made of the packaging material according to any one of the above [1] to [4].

According to the present invention, it is possible to provide a packaging material capable of producing an aesthetic appearance due to metallic luster without using a metal layer or a high-brightness aluminum paste. Further, the packaging material is excellent in safety even when used in a microwave oven, and can be used to form various packaging containers and lids having a high-class feeling due to metallic luster.
Further, according to the manufacturing method of the present invention, the packaging material can be easily manufactured.

It is a schematic sectional drawing which shows an example of the laminated structure of the packaging material of this invention. It is the schematic sectional drawing which shows another example of the laminated structure of the packaging material of this invention. It is the schematic sectional drawing which shows another example of the laminated structure of the packaging material of this invention. It is the schematic sectional drawing which shows another example of the laminated structure of the packaging material of this invention. It is sectional drawing which shows an example of the pouch for the microwave oven in the packaging container of this invention. It is a top view which shows an example of the container with a lid among the packaging containers of this invention. FIG. 6 is a sectional view taken along line IV-IV of FIG. It is the schematic sectional drawing which shows another example of the laminated structure of the packaging material of this invention. It is a schematic plan view which shows another example of the pouch for the microwave oven in the packaging container of this invention. 9 is a cross-sectional view taken along the line XI-XI of FIG.

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

[Packaging material]
The packaging material of the present invention has at least a structure in which a plastic film, a glossy printing layer, and a sealant layer are laminated from the outer layer side in this order. The glossy print layer is characterized by containing a pearl pigment.
By forming the glossy print layer using the pearl pigment in this way, it is possible to give an aesthetic appearance due to the 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 the scale-like fine particle of mica, and has light transmittance. Therefore, by arranging the thin plate-like fine particles in a layered manner, light is multiple-reflected, and a glossy feeling like metal or pearl can be generated.
As described above, the pearl pigment is not a metal itself but mainly composed of a metal oxide, but is a colorant capable of producing a metallic luster.

There are several types of the pearl pigments, but they can be roughly classified into three types: white pearl pigments, interference pearl pigments and colored pearl pigments.
In the white pearl pigment, the coating layer of the mica is a colorless high refractive index material such as titanium dioxide, and the thickness of the coating layer is relatively small, about 0.1 to 0.15 μm, and almost all wavelengths of light are used. It looks white or silver because it reflects.
In the interference pearl pigment, the coating layer of the mica is a colorless high refractive index material such as titanium dioxide, and the thickness of the coating layer is larger than that of the white pearl pigment, which is more than 0.15 μm. Depending on this thickness, the reflected light and the transmitted light change, and various interference colors are generated. Sometimes called iridescent pearls.
The colored pearl pigment is chromatic, and the coating layer of the mica is made of a colored high refractive index material such as ferric oxide, and the periphery of the white pearl pigment is further colored high refractive index material such as ferric oxide or others. There are those coated with the colored pigments of the above, and those in which pigments and other colorants are added to the coating layer of the mica.

The pearl pigment used in the present invention may be any of the above types, but from the viewpoint of obtaining a pearl coating color that gives a high-grade feeling even when viewed from all directions with higher brightness, a white pearl pigment and an interference pearl. It is preferable to include one or more selected from the pigments and one or more selected from the colored pearl pigments. White pearl pigment is preferable as one or more selected from white pearl pigment and interference pearl pigment, and as one or more selected from colored pearl pigment, the coating layer of the mica is colored with ferric oxide or the like. Those made of a high refractive index material and those in which the periphery of the white pearl pigment is coated with a colored high refractive index material are preferable.
In this case, in particular, in order to obtain a deep golden luster even when viewed from all directions, the colored pearl pigment is a colored pearl pigment in which the periphery of the white pearl pigment is coated with ferric oxide or a coating layer of a mica. It is preferable to use a colored pearl pigment in which ferric oxide is used, and further, it is more preferable to use a white pearl pigment as one or more selected from the white pearl pigment and the interfering pearl pigment.

When one or more (A) selected from white pearl pigments and interfering pearl pigments and one or more (B) selected from colored pearl pigments 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. The average particle size in the present specification means the average value of the major axis of any 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 further preferably 60 to 80% by mass of the total solid content of the glossy print layer. ..
In addition to the pearl pigment, the glossy print layer may contain other coloring components, but since the coloring component lowers the brightness, the coloring components other than the pearl pigment in the glossy printing layer may be contained. The content is preferably 0.5% by mass or less.

The method for forming the glossy print layer containing the pearl pigment is not particularly limited, but it can usually be formed by an ink containing the pearl pigment by the printing method of the print layer described later. In addition to the pearl pigment, the ink contains a vehicle made of a binder resin or a solvent.

As the solvent, a solvent used for ordinary pigment ink can be applied. For example, an alcohol solvent such as methanol, ethanol, normal propanol, isopropanol and propylene glycol monomethyl ether, and a ketone such as acetone, methyl ethyl ketone and methyl isobutyl ketone can be applied. System solvents, ester solvents such as methyl acetate, ethyl acetate and normal propyl acetate, aliphatic hydrocarbon solvents such as normal hexane, normal heptane and normal octane, alicyclic hydrocarbons such as cyclohexane, methylcyclohexane and cycloheptane. Examples include solvents, aromatic solvents such as toluene and xylene, mineral spirits and the like. These may be used alone or in combination of two or more.
Of these, it is preferable that no aromatic solvent is contained from the viewpoint of the working environment at the time of printing, food hygiene, and the like.

Further, in general, in aluminum paste, the solvent contains mineral spirit, but the mineral spirit has a high boiling point of 162 to 192 ° C. at 1 atm, and even when heat-dried after printing, it is also possible. It is difficult to completely volatilize and remove it, and even a small residual amount may cause the manufactured packaging material to give off a solvent odor. It is not desirable for the packaging material to generate such a solvent odor, and it is particularly required that the packaging material does not generate a solvent odor as much as possible when the object to be packaged by the packaging material is food.
Therefore, as the solvent used for the ink containing the pearl pigment, it is not preferable to use a solvent having a high boiling point such as mineral spirit, and the boiling point at 1 atm is preferably 150 ° C. or lower, more preferably 130 ° C. Below, it is more preferably 120 ° C. or lower.

As described above, the packaging material does not use the metal itself as the printing layer, unlike the metal layer and the high-brightness aluminum paste, so that it can be safely used in a microwave oven. That is, it can be suitably used for a microwave oven.

(Laminated structure)
FIGS. 1 to 4 show an outline of the laminated structure of the packaging material of the present invention in the thickness direction. In FIGS. 1 to 4, 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 printing layer 3a, and the sealant layer 4 from the outer layer side in this order, and may include other layers as constituent layers.
For example, as shown in FIGS. 1 to 4, an intermediate base material layer 5 laminated on both sides thereof via an adhesive layer 6 may be provided between the glossy printing layer 3a and the sealant layer 4. Further, as shown in FIG. 2, the pattern printing layer 3b may be provided on the outer layer side of the glossy printing layer 3a, or as shown in FIG. 4, the pattern printing layer 3b is provided in parallel with the glossy printing layer 3a. You may be doing it. Further, as shown in FIG. 3, the black background color printing layer 3c may be provided in contact with the inner layer side of the glossy printing layer 3a. Further, as shown in FIG. 4, the white background color printing layer 3d may be provided on the inner layer side of the glossy printing layer 3a. Although not shown, the white background color printing layer 3d may be provided on the inner layer side of the glossy printing layer 3a of FIGS. 1 to 3.
Further, a gas barrier layer (not shown) may be formed between the plastic film 2 and the glossy printing layer 3a or between the glossy printing layer 3a and the sealant layer 4.
Specifically, the following laminated configurations can be exemplified in order from the outer layer side. In addition, "/" means the boundary of each layer.
(1) Plastic film / Glossy printing layer / Intermediate base material layer / Sealant layer (2) Plastic film / Gas barrier layer / Glossy printing layer / Sealant layer (3) Plastic film / Gas barrier layer / Glossy printing layer / Intermediate base material layer / Sealant layer (4) Plastic film / glossy printing layer / gas barrier layer / intermediate base material layer / sealant layer From the viewpoint of making the glossy printing layer 3a visible from the outside, it is formed on the outer layer side of the glossy printing layer 3a. The layer shall have light transmission.
Hereinafter, each layer will be described.

<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 light-transmitting material so that the glossy printing layer 3a can be visually recognized from the outside.
Specifically, for example, a polyolefin resin such as polyethylene (PE) or polypropylene (PP), a cyclic polyolefin resin, a polystyrene resin, an acrylonitrile-styrene copolymer (AS) resin, and an acrylonitrile-butadiene-styrene are used. Polymer (ABS) resin, poly (meth) acrylic resin, polycarbonate resin, polyvinyl alcohol resin, ethylene-vinyl alcohol copolymer (EVOH), ethylene-vinyl ester copolymer saponified product, polyethylene terephthalate (PET) Polybutylene terephthalate (PBT), polyester resin such as polyethylene naphthalate (PEN), polyamide resin such as various nylons (Ny), polyurethane resin, acetal resin, cellulose resin, polyvinylidene chloride resin (PVDC) ) Etc. can be mentioned. Among these, polyolefin-based resins are preferable from the viewpoint of versatility, and polyester-based resins and polyamide-based resins are preferable from the viewpoint of heat resistance and strength.
The plastic film may be uniaxially stretched or biaxially stretched. Further, it may be a composite film in which two or more of the above resin films are laminated. Further, the plastic film may be formed by an inflation method or a melt extrusion coating method.

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

The thickness of the plastic film 2 is not particularly limited and can be appropriately set depending on the intended use of the packaging material 1, but it is usually 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 printing layer 3a containing a pearl pigment between the plastic film 2 and the sealant layer 4. The glossy printing layer 3a gives an aesthetic appearance due to the metallic luster.
The glossy print layer 3a may be formed over the entire surface of the packaging material 1 as shown in FIGS. 1 to 3, or may be formed only on a part of the surface of the packaging material 1 as shown in FIG. It may have been done. Further, as shown in FIG. 2, the pattern printing layer 3b may be provided on a part of the outer layer side of the glossy printing layer 3a formed over the entire surface of the packaging material 1. Further, as shown in FIG. 4, the glossy printing layer 3a and the pattern printing layer 3b may be provided in parallel in the same plane of the packaging material 1.
Further, the glossy print layer 3a may form a pattern such as a character, a figure, a symbol, a pattern, or a pattern.

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 sufficiently impressing the metallic luster.

The glossy print layer 3a, and the pattern print layer 3b, the black background color print layer 3c, and the white background color print layer 3d (hereinafter, these may be collectively referred to as a “print layer”) described later are, for example, plastic. It can be formed on the film 2 or the sealant layer 4 by a known printing method such as a gravure printing method, an offset printing method, a letterpress printing method, or a silk screen printing method using a known ink.
The printing layer is preferably formed by back printing on the surface of the plastic film 2 or the gas barrier layer on the inner layer side. Alternatively, even if it is formed by printing on the surface of the intermediate base material layer 5 or the sealant layer 4 on the outer layer side and then adhering it to the plastic film 2 or the gas barrier layer via an adhesive layer. good. Further, the packaging material 1 may be printed on the entire surface or partially printed.

The ink of the printing layer usually contains a vehicle made of a binder resin or a solvent as a main component, and a colorant such as a dye or a pigment is added and mixed with the ink (the glossy printing layer 3a is the above-mentioned pearl pigment). Is included as an essential ingredient). The colorant of the printing layer may be used alone 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, and the like. 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 Resin, unsaturated polyester resin, thermosetting poly (meth) acrylic resin, melamine resin, urea resin, polyurethane resin, phenol resin, xylene resin, maleic acid resin, nitrocellulose, ethylcellulose, acetylbutyl Fiber element resins such as cellulose and ethyloxyethyl cellulose, rubber resins such as rubber chloride and cyclized rubber, petroleum resins, natural resins such as rosin and casein, oils and fats such as flaxseed oil and soybean oil, and solvents Can be mentioned. These may be used alone 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.
Further, if necessary, for example, a light stabilizer such as a filler, a stabilizer, a plasticizer, an antioxidant, an ultraviolet absorber, a dispersant, a thickener, a desiccant, a lubricant, an antistatic agent, a cross-linking agent, etc. Any of the additives can be added.

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

The pattern printing layer 3b may be any printing layer formed in a color that can be distinguished from the glossy printing layer 3a, and is a broad concept including, for example, characters, figures, symbols, patterns, patterns, solid printing, and the like. Examples of the colorant for the pattern printing layer 3b include general-purpose dyes and pigments (for example, chrome yellow, titanium yellow, valve pattern, cadmium red, ultramarine, cobalt blue and other inorganic pigments, quinacridone red, isoindolinone yellow, phthalocyanine blue and the like. Organic pigments) can be used.
The thickness of the pattern printing layer 3b is not particularly limited, and is preferably about 1.5 to 5 μm, more preferably 1.5 to 3 μm.

<Black background color printing layer>
From the viewpoint of imparting depth and a profound feeling to the metallic luster of the pearl pigment, it is preferable that the black background color printing layer 3c is provided in contact with the inner layer side of the glossy printing layer 3a as shown in FIG.
The black background color printing layer 3c shall have an L ^* a ^* b ^* color system L ^* value of 20 or less according to the International Commission on Illumination (CIE) standard measured in accordance with JIS Z8781-4: 2013. It is preferably 10 or less, and more preferably 10 or less.

The black background color printing layer 3c may be formed on the entire surface of the portion having the glossy printing layer 3a, or may be formed only on a part of the portion having the glossy printing layer 3a. When the black background color printing layer 3c is formed on the entire surface of the portion having the glossy printing layer 3a, it is possible to impart depth and a profound feeling to the metallic luster on the entire surface of the glossy printing layer 3a. Further, when the black background color printing layer is formed in a part of the portion having the glossy printing layer 3a, it is possible to impart a change in metallic luster in the plane. The black background color printing is preferably a single color solid printing.

The thickness of the black background color printing layer 3c may be such that the metallic luster of the glossy printing layer 3a due to the pearl pigment can be emphasized, and is not particularly limited, and is preferably about 1.5 to 5 μm. , More preferably 1.5 to 3 μm.

The method for forming the black background color printing layer 3c is not particularly limited, but it can be formed by printing with an ink using a black dye, a pigment, or the like as a colorant by the above-mentioned printing method. As the black colorant, it is preferable to use a black pigment from the viewpoint of developing a stable black color as the ground color.
As the black pigment used for the black background color printing layer 3c, a black pigment having near-infrared ray reflectivity or near-infrared ray transmission is preferable. Examples of the black pigment having near-infrared reflectivity include a composite oxide in which manganese is essential and containing at least one metal element other than manganese, and examples of the black pigment having near-infrared transparency include azomethinazo. Pigments, perylene-based pigments and the like can be mentioned.

Since the composite oxide has near-infrared reflection characteristics, the packaging material 1 provided with the black background color printing layer can also have the heat-retaining characteristics of the object to be packaged.
The metal element other than manganese contained in the composite oxide may be one kind alone or a combination of two or more kinds. Metallic elements other than manganese contained in the composite oxide include, for example, Group 2 elements such as calcium and barium; Group 3 elements such as yttrium, lanthanum, placeodim and neodym; Group 4 elements such as titanium and zirconium; Group 13 elements such as boron, aluminum, gallium, and indium; metal elements such as Group 15 elements such as antimony and bismuth can be mentioned. Among these, Group 2 elements, Group 4 elements, and Group 15 elements are preferable, calcium, titanium, and bismuth are more preferable, and calcium and titanium are even more preferable. Particularly preferred specific examples of the composite oxide include composite oxides containing manganese, calcium and titanium.
The structure of the composite oxide is not particularly limited, but is preferably a perovskite structure, an orthorhombic structure, a hexagonal structure, or the like, and is preferably a perovskite structure, from the viewpoint of a stable structure and its color development. Is even more preferable.
Manganese-based composite oxides are described, for example, in WO2016 / 125906A1.

The azomethine azo pigment has a diazonium group which is a reaction compound of tetrachlorophthalimide and aminoaniline.
The perylene-based pigment is a pigment having a structure in which two oxygen atoms constituting the six-membered ring of the perylenetetracarboxylic dianhydride are removed, and examples thereof include perylene black.

The average particle size of the black pigment used in the black background color printing layer 3c is preferably 0.1 μm or more, more preferably 0.2 μm or more, from the viewpoint of enhancing the absorbability in the visible light region. Is. The upper limit of the average primary particle size of the black pigment is not particularly limited, but is preferably 3.0 μm or less, more preferably 2.0 μm or less, still more preferably 1.0 μm or less.
The average primary particle size of the black pigment is determined as the mass average value d50 in the particle size distribution measurement by the laser optical diffraction method.

The content of the black pigment in the black background color printing layer 3c is 10 to 50 mass by mass of the total solid content constituting the black background color printing layer 3c from the viewpoint of enhancing the metallic luster and the balance of the coating film strength. %, More preferably 15 to 45% by mass, still more preferably 20 to 40% by mass.

As the black pigment used for the black background color printing layer 3c, it is also possible to use a general-purpose black pigment such as carbon black or titanium black. However, in general-purpose black pigments such as carbon black and titanium black, when the packaging material 1 is for a microwave oven, the portion where carbon black, titanium black or the like is present is locally overheated by the microwave oven. This may cause holes in the packaging material. Therefore, it is necessary to take care to suppress the content of general-purpose black pigments such as carbon black and titanium black when they are used for microwave ovens.

<White background color printing layer>
As shown in FIG. 4, the packaging material of the present invention preferably has a white background color printing layer 3d on the inner layer side of the glossy printing layer 3a. By forming the white background color printing layer 3d, the appearance of the packaged object can be improved depending on the type of the packaged object and the like. When the above-mentioned black background color printing layer 3c is provided, it is preferable to form the white background color printing layer 3d on the inner layer side of the black background color printing layer 3c. The white background color printing layer 3d is preferably formed by single color solid printing.
The white background color printing layer 3d may be formed only on a part of the surface of the packaging material, but as shown in FIG. 4, from the viewpoint of facilitating the effect of improving the appearance of the packaged object, as shown in FIG. It is preferable to form it over the entire surface of the packaging material 1.

As the colorant for the white background color printing layer 3d, a general-purpose white pigment can be used. In addition, in order to adjust the tint of the white background color printing layer 3d, a dye or pigment other than the white pigment may be used as the colorant.
The thickness of the white background color printing layer 3d is not particularly limited, and is preferably about 1.5 to 5 μm, more preferably 1.5 to 3 μm.

<Sealant layer>
In the sealant layer 4, the surface on the inner layer side comes into direct contact with the packaged object and plays a role of protecting the packaged object. In particular, when the packaging material 1 forms a packaging container for a liquid material, it is preferable that the material is such that the liquid material does not permeate, and the innermost layer of the sealant layer 4 is pouched or the like. It is preferable that it has a heat-sealing property.

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

When the packaging material is used for a microwave oven or a retort container, the sealant layer is preferably composed of a resin having excellent heat resistance, specifically, a PP homopolymer, an ethylene-propylene block copolymer, or an ethylene-propylene. A PP resin such as a random copolymer is preferable.
It is preferable to use the PP resin properly according to the purpose. Specifically, an ethylene-propylene block copolymer is preferable when cold resistance is important (for example, packaging material for frozen foods), and an ethylene-propylene random copolymer is important when transparency is important. Combined is preferable, and PP homopolymer is preferable when heat resistance is important. Further, in the case of a container provided with an automatic ventilation mechanism, an ethylene-propylene block copolymer is preferable from the viewpoint of facilitating vapor release due to a decrease in sealing strength at high temperatures.

Further, when the lid of the container with a lid is formed by the packaging material 1, the sealant layer 4 preferably has an easy peel property. The easy peeling property is, for example, that when the sealant layer 4 of the packaging material 1 of the lid of the container with a lid is joined to the container body, the lid is easily peeled off from the container body when the container with the lid is opened. Say. The sealant layer having easy peeling property uses two or more kinds of resins, and one resin (resin having good adhesion to the container body) and another resin (adhesion to the container body is not good). It can be formed by mixing one resin and an incompatible resin). Such a resin cannot be unequivocally stated because it differs depending on the material of the container. For example, when the container is made of PP, it is one resin (resin having good adhesion to the container body) and PP. A sealant layer is formed from a resin obtained by mixing one or more of PE, polybutene, and polystyrene, which are other resins (resins that do not have good adhesion to the container body and are incompatible with the above resin). By doing so, it is possible to impart easy peeling property to the container made of PP.
The sealant layer 4 may be configured as a multilayer structure, and easy peeling property may be imparted only to the side of the sealant layer 4 to be 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, the type and properties of the packaged object, and the like, but is usually preferably about 10 to 200 μm. Further, in the case of a pouch (particularly, a retort pouch), the thickness of the sealant layer 4 is more preferably 20 to 150 μm, still 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 to 80 μm, still more preferably 20 to 60 μm.

<Gas barrier layer>
The 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 the permeation of oxygen, water vapor, etc. between the object to be packaged by the packaging material 1 and the external environment of the packaging material 1. Further, it may be provided with 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 a plurality of two or more layers.
When the gas barrier layer is formed on the outer layer side of the glossy print layer 3a, it is made of a light-transmitting material so that the glossy print layer 3a can be visually recognized from the appearance, like the plastic film 2.

The gas barrier layer can be formed as a thin-film deposition film or a coating film by a known method. The surface forming the gas barrier layer may be surface-treated in advance 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 and the like, glow discharge treatment, oxidant treatment, application of an anchor coat agent and the like.

[Embedded film]
Examples of the vapor deposition film as an example of the gas barrier layer include silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), and boron (. B), titanium (Ti), lead (Pb), zirconium (Zr), yttrium (Y) and other inorganic substances or oxides thereof can be formed. 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. Inorganic oxides are preferred.
Examples of the method for forming the vapor deposition film include vacuum vapor deposition, sputtering, physical vapor deposition (PVD) such as ion plating, and chemical vapor deposition (CVD) such as plasma chemical vapor deposition, thermochemical vapor deposition, and photochemical vapor deposition. Law etc. can be mentioned.

The film thickness of the thin-film film varies depending on the forming material, the required gas barrier performance, and the like, but is usually preferably about 5 to 200 nm, more preferably 5 to 150 nm, and further preferably 10 to 100 nm. In the case of an inorganic oxide such as a silicon oxide or an aluminum oxide, it is preferably about 5 to 100 nm, more preferably 5 to 50 nm, and even more preferably 10 to 30 nm.

[Gas barrier coating film]
As an example of the gas barrier coating film as an example of the gas barrier layer, for example, the general formula R ¹ _n M (OR ² ) _m (in the formula, R ¹ and R ² are organic groups having 1 to 8 carbon atoms, and M is a metal atom. N represents an integer of 0 or more, m represents an integer of 1 or more, and n + m is the atomic value of M), and at least one alkoxide, a polyvinyl alcohol-based resin and / or ethylene-vinyl. A coating solution obtained by polycondensing the alcohol copolymer by the sol-gel method in the presence of a sol-gel method catalyst, acid, water and an organic solvent is applied, and the temperature is 0 to 300 ° C. It can be formed by heat treatment for .05 to 60 minutes.
The coating method can be, for example, a roll coating such as a gravure roll coater, a spray coating, a spin coating, dipping, a brush, a bar coating, an applicator or the like. The dry film thickness of the coating film is preferably about 0.01 to 30 μm, more preferably 0.05 to 20 μm, and further preferably 0.1 to 10 μm by one or a plurality of coatings.
The gas barrier coating film is preferably formed on the surface of the vapor deposition film from the viewpoint of improving the gas barrier property.

Considering the specific configuration of the gas barrier layer, as the packaging material of the present invention, the following laminated configurations (1') to (4') can be exemplified in order from the outer layer side. In addition, "/" means the boundary of each layer.
(1') Plastic film / vapor deposition film / glossy printing layer / sealant layer (2') Plastic film / vapor deposition film / gas barrier coating film / glossy printing layer / sealant layer (3') plastic film / glossy printing layer / vapor deposition film / Intermediate base material layer / Sealant layer (4') Plastic film / Glossy printing layer / Gas barrier coating film / Vapor deposition film / Intermediate base material 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 processing suitability, changing the texture of the packaging material, and using it as a base material for forming another layer. It is a layer provided accordingly. Examples of the constituent material of the intermediate base material layer include a plastic film and paper.
In the case of a plastic film, the same one as the above-mentioned plastic film 2 formed on the outer layer side of the glossy print layer 3a can be used.
In the case of paper, characteristics such as shapeability, bending resistance, and rigidity can be imparted to the packaging material 1, for example, high-size bleached or unbleached kraft paper, pure white roll paper, paperboard, and various types. Processed paper, etc. can be used. The basis weight of the paper is usually preferably about 50 to 600 g / m ² , more preferably 60 to 500 g / m ² , and further preferably 70 to 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 it is used for paper containers such as paper cups and liquid paper containers, it is preferably 200 g / m ² or more.

When the packaging material 1 is used for 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 a plastic film exemplified as a plastic film 2 for a packaging material for a microwave oven and a retort container, and paper.

<Adhesive layer>
In the packaging material 1, each constituent 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 dry laminating adhesive.
Examples of the dry laminating adhesive include polyvinyl acetate adhesives, polyacrylic acid ester adhesives, cyanoacrylate adhesives, ethylene copolymer adhesives, cellulose adhesives, polyester adhesives, and polyamide adhesives. Adhesives, polyimide adhesives, amino resin adhesives such as urea resin and melamine resin, phenol resin adhesives, epoxy adhesives, polyurethane adhesives (for example, cured products of polyols and isocyanate compounds), reactions Examples thereof include mold (meth) acrylic acid-based adhesives, rubber-based adhesives made of chloroprene rubber, nitrile rubber, styrene-butadiene rubber, etc., silicone-based adhesives, alkali metal silicates, inorganic adhesives made of low-melting point glass, and the like.

<Thermal softening resin layer>
As shown in FIG. 8, the packaging material 1 may have the heat-softening resin layer 7 in a part of the region between the plastic film 2 and the sealant layer 4.
As shown in FIG. 8, the heat-softening resin layer 7 is formed in a part near the edge of the packaging material 1, and the heat-softening resin layer 7 has a predetermined strength in a temperature environment of room temperature or lower. However, because it is composed 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 rises, a part of the sealant layer 4 is destroyed and the heat softening resin is used. A part of the layer 7 can be separated from the interface or coagulated and broken to allow steam to escape. Details will be described in the second embodiment of the automatic ventilation mechanism described later.

As the heat-softening resin 7, that is, a resin having a predetermined strength in a temperature environment of room temperature or lower, but whose strength decreases in a high temperature environment, a resin having a melting point of 60 to 110 ° C., preferably 60 to 90 ° C. is used. Can be 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 preferable. As the resin containing polyamide, nitrocellulose cotton and polyethylene wax, MWOP varnish (softening point 105 ° C.) manufactured by DIC Graphics Corporation can be used.

The thickness of the heat-softening resin layer 7 is preferably 1 to 5 μm. By setting the thickness of the heat-softening resin layer 7 to 1 μm or more, the heat-softening resin layer 7 and the sealant layer 4 can be easily destroyed when heated in a microwave oven. Further, by setting the thickness of the heat-softening resin layer 7 to 5 μm or less, it is possible to prevent a part of the packaging material from being raised and the portion from being stretched when the film-shaped packaging material is wound into a roll shape.

[Packaging container]
The packaging container of the present invention is at least partially formed of the packaging material.
By being formed of the packaging material, a high-quality packaging container due to metallic luster can be obtained even if the metal itself is not used.
The packaging material may be applied to a desired portion to which a feeling of luxury due to metallic luster is desired, and the packaging material may be used even if the entire packaging container is formed of the packaging material or only a part of the packaging material is used. You may.
When the packaging material is processed by heat sealing, the packaging material on which the metallic gloss layer formed by the high-brightness aluminum paste is formed is for microwave ovens because the distance of the aluminum particles in the high-brightness aluminum paste is close at the time of heat sealing. In the packaging material of, the risk of sparks due to microwaves in the microwave oven increases. On the other hand, the packaging material of the present invention does not cause such a danger even when heat-sealed.

The type and use of the packaging container of the present invention are not particularly limited, but can impress the purchaser with a sense of luxury when selling the contents contained in the packaging container. Yes, for example, it can be suitably used for food containers, cosmetic containers, and the like.
Examples of the packaging container include a pouch, a container with a lid, a cup, a tray, and the like. These packaging containers include the packaging material as a part. That is, the packaging container may be made of a packaging material containing paper as the intermediate base material layer 5.
Specific examples of the shape of the pouch include the shape of a pouch for a microwave oven as shown in FIG. 5 described later. The pouch may be a retort container (a container that has been sterilized at high temperature and high pressure), and may be a container other than a packaging container for a microwave oven or a retort container.
Further, as a specific shape of the container with a lid, the container body having a storage portion and a lid body joined to the container body so as to seal the storage portion are provided, and the lid body is provided. 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 for a microwave oven or a retort container, it is preferable that the packaging material constituting the container has a laminated structure according to any one of (1) to (4) described above.
At this time, as the plastic film 2, it is preferable to use a single polyester film, a single polyamide film such as nylon, and a composite film containing one or more of the polyester film and the polyamide film.
At this time, 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 the polyester film and the polyamide film, and paper is used. Is preferable.
At this time, as the sealant layer 4, a PP resin such as a propylene homopolymer, an ethylene-propylene block copolymer, or an ethylene-propylene random copolymer, or HDPE is preferable.

More specifically, in the case of a microwave oven or a retort container, it is preferable that the packaging material constituting the packaging container has a laminated structure according to any one of the following (A1) to (A12). In addition, "/" means the boundary of each layer. Further, in (A1) to (A12), PET and Ny are preferably stretched films.
(A1) PET / glossy printing layer / Ny / ethylene-propylene block copolymer (A2) PET / gas barrier layer / glossy printing layer / Ny / ethylene-propylene block copolymer (A3) PET / glossy printing 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) co-extruded stretched film (PET / Ny / PET) PET / glossy print layer / PET / ethylene-propylene block copolymer (PET / ethylene-propylene block copolymer (PET / Ny / PET) A8) Co-extruded stretched film (PET / Ny / PET) / gas barrier layer / glossy printing layer / PET / ethylene-propylene block copolymer (A9) co-extruded stretched film (PET / Ny / PET) / glossy printing 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 printing layer / gas barrier layer / Ny / ethylene-propylene block copolymer

In the case of a packaging container for a microwave oven, the ethylene-propylene block copolymer which is the sealant layer of (A1) to (A12) can be made of a polyethylene resin such as LDPE, LLDPE, MDPE, HDPE.
In the case of adopting the configuration of the automatic ventilation mechanism of the second embodiment described later in the packaging container for a microwave oven, the above-mentioned heat-softening resin is partially formed between the plastic film 2 and the sealant layer 4. The layer 7 may be formed.

(Pouch)
FIG. 5 shows an example of a pouch for a microwave oven, which is an embodiment of the packaging container of the present invention. The pouch 10 shown in FIG. 5 is a standing type microwave oven pouch formed by heat-sealing the body portion 11 and the bottom portion 12. As shown in FIG. 5, the body portion 11 includes a pair of main surface sheets 13 composed of a front main surface sheet 13a and a back main surface sheet 13b arranged so as to face each other, and a pair of superposed main surfaces. The vicinity of the side edge 14 of the sheet 13 is heat-sealed with each other. A bottom sheet 16 forming a bottom portion 12 is arranged between the lower edges 15 of the pair of main surface sheets 13.
Then, an accommodation space 17 for accommodating the contents is formed in the area surrounded by the pair of main surface sheets 13 and the bottom surface sheet 16. The bottom sheet 16 is bent in a convex shape toward the accommodation space 17, and the vicinity of the peripheral edge thereof is heat-sealed together with the lower portion of the overlapping main surface sheets 13. By holding the shape of the lower ends of the pair of main surface sheets 13 by the bottom sheet 16, the pouch 10 is given independence and can be made into a standing type pouch.
The pouch 10 has an opening 19 formed between the front main surface sheet 13a and the upper edge 18 of the back main surface sheet 13b, and the contents can be accommodated from the opening 19. After accommodating the contents, it can be sealed by heat-sealing the vicinity of the upper edge 18 where the opening 19 is formed. When the contents are taken out from the pouch 10, the vicinity of the upper edge 18 is torn from the notch 23 and opened.

The front main surface sheet 13a, the back main surface sheet 13b, and the bottom surface sheet 16 of the pouch 10 can be formed of the packaging material 1. All of these sheets may be formed of the packaging material 1 having the glossy printing layer 3a containing the pearl pigment, or even if only one of the sheets for which metallic luster is required is formed of the packaging material 1. good. In FIG. 5, it is shown that the front surface sheet 13a is formed by the packaging material 1 having a laminated structure as shown in FIG. 2 so as to have the glossy printing layer 3a and the pattern printing layer 3b.
As the sheet other than the sheet in which the packaging material 1 is used, for example, a sheet in which the glossy printing layer 3a containing a pearl pigment is not formed, a sheet in which the packaging material 1 is not formed, or the like can be used.

<Automatic ventilation mechanism>
When the packaging container is for a microwave oven, when the pressure inside the pouch rises due to the steam generated by cooking the food, etc., which is the contents, the steam in the storage space is automatically released to the outside and the pouch bursts. It is preferable to have an automatic steaming mechanism for preventing the above. The automatic ventilation mechanism is preferably formed in the vicinity of the peripheral edge of the container.

A first embodiment of the automatic ventilation mechanism will be described with reference to FIG. The microwave oven pouch 10 shown in FIG. 5 has a first unsealed region 21 that is not heat-sealed in the vicinity of the side edge 14 near the upper side of the pouch. The first unsealed region 21 reaches the side edge 14 and has an opening 22. Further, the first unsealed area 21 projects toward the accommodation space 17. Further, the heat seal portion 25 overhangs the accommodation space 17 side so as to surround the first unsealed region 21 overhanging the accommodation space 17, forming the overhanging portion 25a. More specifically, the first unsealed region 21 and the accommodation space 17 are separated from each other, and the overhanging portion 25a is formed so as to be continuously connected to the heat sealing portion 25 that seals the pouch.
In the microwave oven pouch 10 shown in FIG. 5, the automatic ventilation mechanism 20 is provided by the heat-sealed portion (overhanging portion 25a) overhanging the opening 22, the first unsealed region 21, and the accommodation space 17 as described above. It is formed. Specifically, when the pressure inside the container rises due to heating, the overhanging portion 25a of the heat-sealing portion 25 receives a strong load and peels off first, so that the accommodation space 17 and the first not yet are used. It communicates with the seal region 21 and allows steam to escape to the outside.
Further details of the automatic ventilation mechanism as shown in FIG. 5 are described in JP-A-2015-120550, JP-A-2016-74457, and JP-A-2016-74458.

In the pouch 10 shown in FIG. 5, the second unsealed region 23 is formed on the side edge 14 opposite to the first unsealed region 21. The second unsealed region 23 is formed from the viewpoint of improving the yield of forming the opening 22 of the first unsealed region 21 when a plurality of pouches 10 are continuously formed and then cut one by one. It does not necessarily have to be formed.

Further, a second embodiment of the automatic ventilation mechanism will be described with reference to FIGS. 8 to 10.
The pouch 10 shown in FIG. 9 is an edge portion of the packaging material shown in FIG. 8 (a packaging material between the plastic film 2 and the sealant layer 4 having a heat-softening resin layer 7 in a part near the edge portion). The surrounding area is heat-sealed to form a pouch. Further, FIG. 10 is a cross-sectional view of the heat-sealed portion 25 around the edge portion of the pouch 10 of FIG. 9 in XI-XI.
As shown in FIG. 9, the heat-softening resin layer 7 is formed from the inner edge to the outer edge of the heat-sealed portion 25 that seals the pouch in at least a part of the region of the heat-sealed portion 25 of the pouch 10. You will need it. The strength of the heat-softening resin layer 7 provided at such a position decreases as the heat-softening resin layer 7 is heated in a microwave oven to a high temperature.
As shown in FIG. 10, in the heat-sealed portion 25 of the pouch 10, the heat-softening resin layer 7 is heated by 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, a part of the sealant layer 4 is destroyed and a part of the heat-softening resin layer 7 is peeled off or aggregated and destroyed starting from an arbitrary portion A of the sealant layer 4 near the inner edge of the heat-sealed portion 25. (The broken line B shows a virtual line in which the sealant layer 4 is broken and the heat-softening resin layer 7 is interfacially peeled or aggregated and broken.) As a result, air or steam escapes from the fractured portion, and the internal pressure of the pouch 10 can be reduced.
The automatic ventilation mechanism of the second embodiment can also be applied to a container with a lid, which will be described later.

As the packaging material constituting the container provided with the second embodiment of the automatic ventilation mechanism, it is preferable to select a resin that easily disintegrates as the resin constituting the sealant layer. Specifically, LLDPE is preferable. Further, the packaging material constituting the container provided with the second embodiment of the automatic ventilation mechanism preferably has a laminated structure according to any one of the following (B1) to (B6). In addition, "/" means the boundary of each layer. Further, in (B1) to (B6), PET and Ny are preferably stretched films.
(B1) PET / glossy printing layer / heat-softening resin layer / LLDPE
(B2) PET / gas barrier layer / glossy printing layer / heat-softening resin layer / LLDPE
(B3) PET / glossy printing layer / gas barrier layer / heat-softening resin layer / LLDPE
(B4) Ny / glossy printing layer / heat-softening resin layer / LLDPE
(B5) Ny / gas barrier layer / glossy printing layer / heat-softening resin layer / LLDPE
(B6) Ny / glossy printing layer / gas barrier layer / heat-softening resin layer / LLDPE

(Container with lid)
6 and 7 show an example of an embodiment of the container with a lid of the present invention. FIG. 6 is a top view, and FIG. 7 is a sectional view taken along line IV-IV of FIG. The container with a lid 30 shown in FIGS. 6 and 7 includes a container body 32 in which the storage portion 31 is formed, and a lid 33 joined to the container body 32 so as to seal the storage portion 31 of the container body 32. ing. In FIG. 6, the shape of the container body 32 is substantially rectangular, but is not particularly limited. Further, 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 molding.
Further, since the material of the container body 32 is to be joined to the lid 33, it is usually a thermoplastic resin such as PP or PET, and particularly in the case of a container with a lid for a microwave oven. PP is preferably used from the viewpoint of heat resistance and the like.

It is preferable that the lid 33 of the container with a lid 30 is formed of the packaging material 1. According to such a lid 30, the packaging material 1 having the glossy printing layer 3a containing a pearl pigment can give an aesthetic appearance to the container with a lid 30, and the contents contained in the container 30 with a lid. The high-class feeling of the object can be impressed from the appearance of the container with a lid 30. In addition, in FIG. 6, it is shown that the lid 33 is formed by the packaging material 1 having a laminated structure as shown in FIG. 2 so as to have the glossy printing layer 3a and the pattern printing layer 3b.

The lid 33 has an easy peel property as described in the above description of the sealant layer 4 of the packaging material 1 from the viewpoint of peeling from the container body 32 to facilitate opening of the container 30 with a lid. Is preferable.
Specifically, the lid 33 and the container body 32 are joined by the joining line 35 of the flange portion 34 of the container body 32. The joining line 35 may be formed by, for example, a heat seal between the lid 33 and the flange portion 34, or may be formed by a separate component such as an adhesive layer.

When the container with a lid 30 is used for a microwave oven, the container with a lid is attached when the pressure inside the container with a lid increases due to steam generated by cooking food or the like contained in the container body 32. It is preferable to have an automatic ventilation mechanism (third embodiment of the automatic ventilation mechanism) that automatically releases the steam in the container 30 to the outside and prevents the container 30 with a lid from bursting.
For example, the flange portion 34 has a protrusion 34a protruding toward the center of the container body 32, and the joining line 35 is also formed to protrude toward the center of the container along the protrusion 34a. It has a line 35a. Since the joining line 35 is formed in such a form, it becomes easy to peel off from the protruding line 35a of the joining line 35 as the pressure inside the container 30 with a lid rises due to heating, and the container body 32 The accommodating portion 31 and the outside can be communicated with each other, and the steam in the container with a lid 30 can be released to the outside.
In the container with a lid 30 shown in FIGS. 6 and 7, the protruding portions 34a are formed on the opposite long sides of the flange portions 34, respectively, but the two protruding portions 34a are not necessarily formed. You may.

Further, as the lid 33 constituting the container with a lid 30, the packaging material shown in FIG. 8 (between the plastic film 2 and the sealant layer 4 and having a heat-softening resin layer 7 in a part near the edge portion is provided. By using the packaging material), steam can be released when heated in a microwave oven for the same reason as described in the second embodiment of the automatic ventilation mechanism described above.

(Cover)
The lid of the present invention is formed of the above-mentioned packaging material of the present invention.
The packaging material constituting the lid preferably has a laminated structure according to any one of (1) to (4) described above.
When the lid is used for a microwave oven or as a retort container, the plastic film 2 uses a single polyester film, a single polyamide film such as nylon, or a composite film containing one or more of a polyester film and a polyamide film. Is preferable.
When the lid is used for a microwave oven or as a retort container, the intermediate base material layer 5 includes a single polyester film, a single polyamide film such as nylon, and a composite film containing one or more of a polyester film and a polyamide film. , And any of the papers are preferred.
When the lid is used for a microwave oven or a retort container, it is preferable to use a film made of a resin having both heat resistance and easy peeling property as the sealant layer 4. Such a film differs depending on the type of container, but when the container is a PP-based resin which is a general-purpose resin, a film made of a mixture of PP and one or more selected from PE, polybutene and polystyrene may be used. preferable. The sealant layer 4 may be configured as a multilayer structure, and easy peeling property may be imparted only to the side of the sealant layer to be joined to the container body (the innermost layer in the packaging material).

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

When the configuration of the second embodiment of the automatic ventilation mechanism described above is adopted for the lid, the heat-softening resin layer 7 described above is formed in a part between the plastic film 2 and the sealant layer 4. Just do it.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

[Making packaging materials]
(Example 1)
From the outer layer side, a packaging material sample laminated in the order of plastic film / vapor deposition film / gas barrier coating film / glossy printing layer / white background color printing layer / adhesive layer / intermediate base material layer / adhesive layer / sealant layer is prepared. bottom. The structure of each layer is as follows.
-Plastic film: PET (thickness 12 μm)
-Gas barrier layer: A corona discharge treatment was applied to one surface of the plastic film, and then a thin-film silicon oxide film having a thickness of 10 nm was formed. Further, after plasma treatment with a mixed gas of oxygen and argon, a coating liquid containing ethyl silicate and polyvinyl alcohol as main components was applied with a gravure roll coater to form a coating film having a dry film thickness of 300 nm.
-Glossy printing layer: The following golden ink 1 for a glossy printing layer was gravure-printed on a part of the surface of the gas barrier layer and dried to form a glossy printing layer having a dry film thickness of 3 μm.
-White background color printing layer: Further, a white pigment ink was gravure-printed and dried on the entire surface above the glossy printing layer to form a white background color printing layer having a dry film thickness of 3 μm.
-Intermediate base material layer: PET (thickness 15 μm) was bonded to the surface of the printed layer by a dry laminating method using a polyurethane adhesive.
-Sealant layer: CPP (ethylene-propylene block copolymer single layer film, thickness 70 μm) was bonded to the surface of the intermediate base material layer by a dry laminating 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 coating layer of mica is ferric oxide, average particle size 15 μm): 20 parts by mass ・ Anti-settling agent (fine particle silica) ): 0.1 part by mass ・ Binder resin (polyurethane resin): 10 parts by mass ・ Solvent (mixed solvent of propylene glycol monomethyl ether, normal propyl acetate, ethyl acetate, isopropanol): 60 parts by mass

(Example 2)
In the printing layer of Example 1, instead of the white background color printing layer, the following black background color printing layer ink is gravure-printed on the glossy printing layer and dried, and black background color printing with a dry film thickness of 2 μm is performed. A layer was formed, and a packaging material sample was prepared in the same manner as in Example 1 except for the above.
<Ink for black background printing layer>
-Binder resin (acrylic urethane resin): 15 parts by mass-Black pigment (composite oxide containing manganese, calcium and titanium as metal elements, "MPT-370", manufactured by Ishihara Sangyo Co., Ltd., average primary particle diameter 0.8 μm ): 5 parts by mass ・ Solvent (mixed solvent of methyl ethyl ketone, ethyl acetate, butyl acetate and isopropanol): 80 parts by mass

(Comparative Example 1)
In Example 1, a packaging material sample was prepared in the same manner as in Example 1 except that the glossy print layer was configured as shown below.
-Glossy printing layer: The following golden ink 2 for glossy printing layer (high-brightness aluminum paste) was gravure-printed on the surface of the gas barrier layer and dried to form a glossy printing layer having a dry thickness of 3 μm.

<Gold ink 2 for glossy print layer>
・ Aluminum scales: 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 (mixed solvent of propylene glycol monomethyl ether, normal propyl acetate, ethyl acetate, isopropanol): 70 parts by mass

When the surface of the outer layer of each packaging material produced in the above Examples and Comparative Examples was visually observed, the glossy printing layer made of pearl pigment (Example 1) was similar to the glossy printing layer made of high-brightness aluminum paste (Comparative Example 1). A golden metallic luster was observed. Further, in the case of forming the black background color printing layer (Example 2), the metallic luster due to the golden pearl coating color deeper than that of Example 1 was recognized in the glossy printing layer.
In the packaging material sample of Comparative Example 1, a slight solvent odor, which was considered to be caused by the mineral spirit, was observed.

[Evaluation of retort pouch]
(Example 3)
Using the packaging material sample prepared in Example 1, a pouch 10 as shown in FIG. 5 was prepared and sealed.

(Comparative Example 2)
Using the packaging material sample prepared in Comparative Example 1, a pouch 10 as shown in FIG. 5 was prepared and sealed.

Twenty points of each pouch prepared 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 3. On the other hand, in the retort pouch of Comparative Example 2, 7 out of 20 points had holes in the portion where the glossy print layer was formed.
From this, it is said that the retort pouch produced by the packaging material of the present invention can be safely applied to cooking in a microwave oven even when the high retort pouch treatment is performed at 130 ° C. or higher. I can say.

1 Packaging material 2 Plastic film 3a Glossy printing layer 3b Picture printing layer 3c Black background color printing layer 3d White background color printing layer 4 Sealant layer 5 Intermediate base material layer 6 Adhesive layer 7 Heat-softening resin layer 10 Pouch 11 Body 12 Bottom 13 Main surface sheet 14 Side edge 15 Lower edge 16 Bottom sheet 17 Storage space 18 Upper edge 19 Opening 20 Automatic ventilation mechanism 21 1st unsealed area 22 Opening 23 2nd unsealed area 24 Notch 25 Heat-sealed part 30 With lid Container 31 Storage part 32 Container body 33 Lid 34 Flange part 35 Joining line

Claims (8)

At least, the packaging material has a structure in which the plastic film, the glossy printing layer and the sealant layer are laminated from the outer layer side in this order, and the glossy printing layer contains a pearl pigment and is formed on the inner layer of the glossy printing layer. A packaging material for microwave ovens that has a white background color printing layer in contact with it. The packaging material according to claim 1, wherein the pearl pigment contains one or more selected from white pearl pigments and interference pearl pigments, and one or more selected from colored pearl pigments. In the method for manufacturing the packaging material according to claim 1 or 2 .
The glossy printing layer is formed of an ink containing the pearl pigment, and the boiling point of the solvent contained in the ink at 1 atm at 1 atm is 150 ° C. or lower, which is a method for producing a packaging material. A packaging container in which at least a part thereof is made of the packaging material according to claim 1 or 2 . The packaging container according to claim 4 , wherein the packaging container is a pouch. A container with a lid including a container body having an accommodating portion and a lid body joined to the container body so as to seal the accommodating portion, wherein the lid body is formed of the packaging material. Item 4. The packaging container according to Item 4. The packaging container according to any one of claims 4 to 6 , which is a retort container. A lid made of the packaging material according to claim 1 or 2 .

Images