JP7415118B2 - How to sort packaging materials, packaging materials and retort containers - Google Patents

Description

The present invention relates to a method for sorting packaging materials, packaging materials, and retort containers.

Packaging materials are sometimes decorated with high-brightness metallic luster in order to create a sense of luxury and luxury for the packaged item and create an aesthetic appearance. As such a decoration means, for example, forming a metal layer such as a metal vapor deposition film or metal foil is generally performed.

However, packaging materials using metal layers have a problem of increased cost. In addition, among the metal layers, metal vapor-deposited films cannot be manufactured in-line with other layers that make up the packaging material, resulting in poor manufacturing efficiency, and among the metal layers, metal foils are difficult to handle. There is a problem.
Furthermore, when packaging materials using a metal layer are heated in a microwave oven, the microwaves in the microwave may reflect off the surface of the metal layer, creating sparks, which may cause damage to the microwave or an accident. However, there is also the problem that the contents inside the packaging container cannot be sufficiently heated.

For this reason, for example, Patent Document 1 proposes a packaging material in which a glossy layer is formed with an ink containing a high-brightness aluminum paste at a predetermined concentration instead of a metal layer.

JP 2017-81589 Publication

However, with the packaging material disclosed in Patent Document 1, which has a metallic luster without using a metal layer, there have been cases where it has been pointed out that the appearance changes during the distribution process of the packaging material, although the number of occurrences is small. .

The present invention has been made to solve the above technical problems, and provides a packaging that can create an aesthetic appearance with metallic luster without using a metal layer, and can suppress changes in appearance during the distribution process. The purpose is to provide a method for selecting materials.
Further, the present invention provides a packaging material that can produce an aesthetic appearance due to metallic luster without using a metal layer and suppresses changes in appearance during the distribution process, and a packaging container using the packaging material. With the goal.

As a result of intensive investigation into the causes of changes in the appearance of packaging materials during the distribution process, the present inventors found that when the strength of the retort treatment for pressurized and heat sterilization is increased than usual (specifically, It has been found that the appearance of packaging materials changes when subjected to retort treatment at high temperatures of 130° C. or higher. The present inventors conducted further studies and completed the present invention.

That is, the present invention provides the following [1] to [3].
[1] A method for sorting a packaging material having a structure in which at least a plastic film, a printing layer, and a sealant layer are laminated in this order from the outer layer side, the printing layer being a glossy printing layer containing a glitter pigment. In the case where d ₁ is the angle indicating 1/2 of the intensity of the reflected light in the specular reflection direction of the packaging material measured under measurement condition 1 below, A method for sorting packaging materials, in which a passing line is one that satisfies the following formula (1), where _d2 is an angle that indicates 1/2 the intensity of reflected light in the reflection direction.
|(d ₁ - d ₂ )/d ₁ |×100 ≦ 8.0% (1)
<Measurement conditions 1>
A black plate is bonded to the surface of the packaging material on the sealant layer side via a transparent adhesive layer to produce sample A in which the packaging material, the transparent adhesive layer, and the black plate are laminated. Visible light rays inclined at 45 degrees from the normal direction of the sample A are incident on the surface of the packaging material side of the sample A, and the specular reflection direction of the incident light is set to 0 degrees of the reference angle, and the reference angle is set as the center. The intensity of the reflected light is measured every 0.1 degree within a range of ±15.0 degrees.
<Measurement conditions 2>
The packaging material is subjected to batch retort treatment at 135° C. for 30 minutes using a hot water shower type retort device to obtain a retort-treated packaging material. A black plate is bonded to the surface of the sealant layer side of the packaging material to be retorted via a transparent adhesive layer to produce sample B in which the packaging material to be retorted, the transparent adhesive layer, and the black plate are laminated. A visible light beam tilted by 45 degrees from the normal direction of the sample B is incident on the surface of the sample B on the side of the packaging material to be retorted, and the standard angle is set to 0 degrees with the direction of specular reflection of the incident light being 0 degrees. The intensity of the reflected light is measured every 0.1 degree within a range of ±15.0 degrees from the center.

[2] A packaging material having a structure in which at least a plastic film, a printing layer, and a sealant layer are laminated in this order from the outer layer side, the printing layer having a glossy printing layer containing a glitter pigment, The angle indicating 1/2 of the intensity of reflection in the specular reflection direction of the packaging material measured under measurement condition 1 above is d ₁ , and the angle indicating the intensity of reflection in the specular reflection direction of the packaging material measured under measurement condition 2 above is A packaging material that satisfies the following formula (1), where _d2 is the angle that indicates 1/2 of the strength.
|(d ₁ - d ₂ )/d ₁ |×100 ≦ 8.0% (1)
[3] A retort container at least partially formed of the packaging material described in [2] above.

According to the present invention, it is possible to provide a method for sorting packaging materials that can produce an aesthetic appearance due to metallic luster without using a metal layer, and can suppress changes in appearance during the distribution process. Further, according to the present invention, there is provided a packaging material that can produce an aesthetic appearance due to metallic luster without using a metal layer and that suppresses changes in appearance during the distribution process, and a packaging container using the packaging material. can be provided.

FIG. 1 is a schematic cross-sectional view showing an example of the laminated structure of the packaging material of the present invention. FIG. 1 is a schematic cross-sectional view showing an example of the laminated structure of the packaging material of the present invention. FIG. 1 is a schematic cross-sectional view showing an example of the laminated structure of the packaging material of the present invention. FIG. 1 is a schematic cross-sectional view showing an example of the laminated structure of the packaging material of the present invention. It is a sectional view showing an example of the pouch for microwave ovens among the packaging containers of the present invention. It is a top view showing an example of a container with a lid among packaging containers of the present invention. 7 is a sectional view taken along line IV-IV in FIG. 6. FIG. It is a figure explaining the measuring method of the intensity of the reflected light of a packaging material. 3 is an intensity distribution diagram of reflected light of the packaging material of Example 1. FIG. 3 is an intensity distribution diagram of reflected light of the packaging material of Comparative Example 1. FIG. 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 schematic plan view which shows another example of the pouch for microwave ovens of the packaging containers of this invention. 13 is a sectional view taken along line XI-XI in FIG. 12. FIG.

Hereinafter, the packaging material of the present invention, and the packaging container and lid using the packaging material will be described in detail. Note that the numerical range notation "AA to BB" in this specification means "more than or equal to AA and less than or equal to BB." Further, hereinafter, the "intensity of reflected light" may be referred to as "reflection intensity."

[How to sort packaging materials]
The method for sorting packaging materials of the present invention is a method for sorting packaging materials having a structure in which at least a plastic film, a printed layer, and a sealant layer are laminated in this order from the outer layer side, and the printed layer has a glittering layer. In the case of having a glossy printing layer containing a pigment, d ₁ is the angle indicating 1/2 of the intensity of the reflected light in the specular reflection direction of the packaging material measured under measurement condition 1 below, and under measurement condition 2 below. When the angle indicating 1/2 of the measured reflection intensity in the specular reflection direction of the packaging material is defined as _d2 , the passing line is defined as one that satisfies the following formula (1).
|(d ₁ - d ₂ )/d ₁ |×100 ≦ 8.0% (1)

<Measurement conditions 1>
A black plate is bonded to the surface of the packaging material on the sealant layer side via a transparent adhesive layer to produce sample A in which the packaging material, the transparent adhesive layer, and the black plate are laminated. Visible light rays inclined at 45 degrees from the normal direction of the sample A are incident on the surface of the packaging material side of the sample A, and the specular reflection direction of the incident light is set to 0 degrees of the reference angle, and the reference angle is set as the center. The intensity of the reflected light is measured every 0.1 degree within a range of ±15.0 degrees.
<Measurement conditions 2>
The packaging material is subjected to batch retort treatment at 135° C. for 30 minutes using a hot water shower type retort device to obtain a retort-treated packaging material. A black plate is bonded to the surface of the sealant layer side of the packaging material to be retorted via a transparent adhesive layer to produce sample B in which the packaging material to be retorted, the transparent adhesive layer, and the black plate are laminated. A visible light beam tilted by 45 degrees from the normal direction of the sample B is incident on the surface of the sample B on the side of the packaging material to be retorted, and the standard angle is set to 0 degrees with the direction of specular reflection of the incident light being 0 degrees. The intensity of the reflected light is measured every 0.1 degree within a range of ±15.0 degrees from the center.

In the packaging material sorting method of the present invention, when the printing layer has a glossy printing layer containing a glittering pigment, the packaging material has a reflection intensity of 1/2 of the reflection intensity in the specular reflection direction of the packaging material measured under the measurement condition 1 above. The above formula (1) is satisfied when the angle indicating the intensity is d ₁ and the angle indicating the reflection intensity of 1/2 of the reflection intensity in the specular reflection direction of the packaging material measured under measurement condition 2 is d ₂ . Packaging materials are recognized as passing the line and are sorted.
Each measurement condition and equation (1) will be explained below.

<<Measurement conditions>>
FIG. 8 is a diagram illustrating a method for measuring the reflection intensity of a packaging material.
In order to measure the reflection intensity of a packaging material, first, a sample 100 is prepared in which a black plate 50 is bonded to the surface of the packaging material 1 on the sealant layer 4 side with a transparent adhesive layer 40 interposed therebetween. Next, visible light rays inclined at 45 degrees from the normal direction of the sample 100 are incident on the surface of the sample 100 on the packaging material 1 side. A solid arrow in FIG. 8 indicates incident light. Then, using the regular reflection direction of the incident light (the direction of the broken line arrow in Figure 8) as a reference angle, the intensity of the reflected light was measured at every 0.1 degree within a range of ±15.0 degrees around the reference angle. do. Note that the plus direction means a direction moving away from the incident light, and the minus direction means a direction approaching the incident light.

In measurement condition 1, as the packaging material constituting sample A, a packaging material that has not been subjected to retort treatment or high retort treatment is used. In measurement condition 2, as the packaging material constituting sample B, a packaging material subjected to high retort processing is used. Note that the packaging material used for Sample A and Sample B may be one cut out from a packaging container. For example, a pouch may be made using a packaging material, the pouch may be subjected to high-retort treatment, and then the packaging material may be cut out and used as the packaging material constituting sample B.

The transparent adhesive layer 40 of the sample 100 may have a refractive index difference of 0.05 or less between the refractive index of the adherend 10 and the black plate 50, preferably 0.05 or less. It is 00. In this specification, the refractive index means the refractive index at a wavelength of 589 nm.
There is no particular restriction on the device for measuring the reflection intensity, and a general-purpose variable angle photometer (goniophotometer) can be used. In the present invention, a variable-angle photometer manufactured by Murakami Color Research Institute Co., Ltd., product number GP-200 (inclination angle within the luminous flux within 0.5 degrees) is used, and the scale of the receiving aperture is "4", and the scale of the luminous aperture is The scale was set to "3".

The high retort treatment under measurement condition 2 is performed using a batch type hot water shower type retort device at a hot water temperature of 135° C. for 30 minutes. Further conditions for the high retort treatment preferably follow the conditions in the examples.

<<Formula (1)>>
The light reflected by a packaging material having a glossy print layer containing a glittering pigment has a strong intensity in the direction of specular reflection, and thus develops a metallic luster. Furthermore, with normal attentiveness, humans do not recognize differences in intensity (brightness) in the range of the maximum intensity to 1/2 of the maximum intensity. Therefore, the range from the maximum intensity to 1/2 of the maximum intensity can be said to be an important angular range for humans to perceive a metallic luster. Therefore, it can be said that equation (1) indicates the rate of change in the angular range, which is important for humans to perceive a metallic luster, before and after high-retort processing.

If "|(d ₁ - d ₂ )/d ₁ | , which means that it becomes significantly narrower.
Therefore, if a packaging material that does not satisfy formula (1) is subjected to high-retort treatment, the design will change to a design that is not intended by the manufacturer. In addition, even if packaging materials that do not satisfy formula (1) have the same metallic luster (same appearance) at the time of manufacture, there are differences between those that have been subjected to high retort treatment during the distribution process and those that have not been subjected to high retort treatment. Since the metallic luster will be different, it may cause problems in product management or may give a sense of discomfort to consumers when the two are displayed side by side.
Therefore, by selecting packaging materials that satisfy formula (1) as a passing line, it is possible to suppress changes in the metallic luster of the packaging materials (changes in appearance) during the distribution process, and to improve the design quality. It becomes possible to stably supply packaging materials with a stabilized level of

Furthermore, when metal scales are used as the glitter pigment, the fact that formula (1) is not satisfied indicates that the arrangement of the metal scales within the glossy printing layer may change due to high retort treatment. For example, if the absolute value of equation (1) is removed and "((d ₁ - d ₂ )/d ₁ ) x 100" becomes smaller than -8.0%, the arrangement of the metal scales is disturbed by the high retort treatment, This indicates that the spacing between the metal scales may become narrower. If the distance between the metal scales becomes narrow, sparks may occur when heated in a microwave oven, or holes may occur due to localized overheating.
Therefore, by selecting the packaging materials that satisfy formula (1) as a passing line, it is possible to prevent sparks from occurring or holes caused by localized overheating when heating in a microwave oven after high-retort treatment. This makes it possible to stably supply packaging materials with excellent safety.
That is, the method for sorting packaging materials of the present invention is also useful as a method for sorting packaging materials for microwave ovens.

"|(d ₁ - d ₂ )/d ₁ |×100" in formula (1) is preferably 6.0% or less, more preferably 4.0% or less.

FIG. 9 is a reflection intensity distribution diagram of the packaging material of Example 1, where the solid line shows the reflection intensity before the high retort treatment and the dotted line shows the reflection intensity after the high retort treatment. Moreover, FIG. 10 is a reflection intensity distribution diagram of the packaging material of Comparative Example 1, where the solid line shows the reflection intensity before the high retort treatment and the dotted line shows the reflection intensity after the high retort treatment. However, in FIGS. 9 and 10, the reflection intensity at each angle is standardized by setting the reflection intensity at the reference angle to 100.
From the comparison between Figures 9 and 10, it can be seen that the packaging material of Comparative Example 1 has a change in reflection intensity before and after high retort treatment, whereas the packaging material of Example 1 has a change in reflection intensity before and after high retort treatment. It can be confirmed that the intensity has hardly changed. Note that the value of "|(d ₁ - d ₂ )/d ₁ |×100" is 3.4% in Example 1 and 12.5% in Comparative Example 1.

The packaging material sorting method of the present invention is preferably applied to packaging materials that have excellent metallic luster and have a _d1 of 2.0 degrees or less. This is because the stability of the design is important in packaging materials that exhibit such a high level of metallic luster. d ₁ is more preferably 1.8 degrees or less, still more preferably 1.7 degrees or less.
Note that if _d1 is too small, the reflected light may feel dazzling. Therefore, _d1 is preferably 1.0 degrees or more, more preferably 1.2 degrees or more.

In this specification, d ₁ and d ₂ are "α1", which is the positive angle at which the intensity of the reflected light at the reference angle first reaches 1/2 or less, When the angle in the negative direction that first reaches an intensity of 1/2 or less is "α2", the angle is calculated by the formula "(α1+|α2|)/2".

In the packaging material sorting method of the present invention, an angle indicating 1/20 of the intensity of reflected light in the specular direction of the packaging material measured under measurement condition 1 above is d ₃ , and the packaging material measured under measurement condition 2 above. It is preferable that the pass line satisfies the following formula (2), where _d4 is an angle that indicates an intensity of 1/20 of the intensity of the reflected light in the regular reflection direction.
|(d ₃ - _{d 4} )/d ₃ |×100 ≦ 15.0% (2)

When a human observes a visual object from the specular reflection direction, it is possible to detect brightness up to 1/20 of the reflection intensity at the reference angle. Therefore, the effect of the present invention can be further enhanced by setting the passing line to be one that satisfies the above formula (2).

"|(d ₃ - d ₄ )/d ₃ |×100" in formula (2) is preferably 12.0% or less, more preferably 10.0% or less, and 8.0% It is more preferable that it is the following.

In this specification, d ₃ and d ₄ are "η1", the angle in the positive direction at which the intensity of the reflected light first reaches 1/20 or less of the intensity of the reflected light at the reference angle; When the angle in the negative direction that first reaches an intensity of 1/20 or less is "η2", the angle is calculated by the formula "(η1+|η2|)/2".

Examples of the glitter pigment in the glossy printing layer include metal scales and pearl pigments.
The metal scales and pearl pigment will be described in the embodiment of the packaging material of the present invention, which will be described later. The plastic film, printing layer, and sealant layer that constitute the packaging material will also be described in the embodiment of the packaging material of the present invention, which will be described later.

[Packaging material]
The packaging material of the present invention is a packaging material having a structure in which at least a plastic film, a printing layer, and a sealant layer are laminated in this order from the outer layer side, and the printing layer is a glossy printing layer containing a glitter pigment. , and d 1 is an angle indicating 1/2 of the reflection intensity in the specular reflection direction of the packaging material measured under measurement condition 1 below, and d ₁ is the angle in the specular reflection direction of the packaging material measured under measurement condition 2 below. The following formula (1) is satisfied, where _d2 is an angle indicating 1/2 of the intensity of the reflected light.
|1-( _d2 / _d1 )|×100 ≦ 8.0% (1)

<Measurement conditions 1>
A black plate is bonded to the surface of the packaging material on the sealant layer side via a transparent adhesive layer to produce sample A in which the packaging material, the transparent adhesive layer, and the black plate are laminated. Visible light rays inclined at 45 degrees from the normal direction of the sample A are incident on the surface of the packaging material side of the sample A, and the specular reflection direction of the incident light is set to 0 degrees of the reference angle, and the reference angle is set as the center. The intensity of the reflected light is measured every 0.1 degree within a range of ±15.0 degrees.
<Measurement conditions 2>
The packaging material is subjected to batch retort treatment at 135° C. for 30 minutes using a hot water shower type retort device to obtain a retort-treated packaging material. A black plate is bonded to the surface of the sealant layer side of the packaging material to be retorted via a transparent adhesive layer to produce sample B in which the packaging material to be retorted, the transparent adhesive layer, and the black plate are laminated. A visible light beam tilted by 45 degrees from the normal direction of the sample B is incident on the surface of the sample B on the side of the packaging material to be retorted, and the standard angle is set to 0 degrees with the direction of specular reflection of the incident light being 0 degrees. The intensity of the reflected light is measured every 0.1 degree within a range of ±15.0 degrees from the center.

The details of measurement conditions 1 and 2 are the same as the packaging material sorting method of the present invention described above.
Further, the embodiment of formula (1), the embodiment of _d1 , the technical objection of formula (1), and the technical objection of _d1 are the same as the packaging material sorting method of the present invention described above. be.

Furthermore, in the packaging material of the present invention, an angle d ₃ indicating an intensity of 1/20 of the intensity of the reflected light in the specular reflection direction of the packaging material measured under measurement condition 1 above, It is preferable that the following formula (2) be satisfied, where _d4 is an angle that indicates an intensity that is 1/20 of the intensity of reflected light in the specular reflection direction.
|(d ₃ - _{d 4} )/d ₃ |×100 ≦ 15.0% (2)

The embodiment of formula (2) and the technical objection to formula (2) are the same as the packaging material sorting method of the present invention described above.

<Laminated structure>
1 to 4 schematically show the laminated structure in the thickness direction of the packaging material of the present invention. 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 only needs to have at least the plastic film 2, the glossy print layer 3a, and the sealant layer 4 laminated in this order from the outer layer side, and may also include other layers as constituent layers.
For example, as shown in FIGS. 1 to 4, an intermediate base material layer 5 may be provided between the glossy printing layer 3a and the sealant layer 4, which is laminated on both sides with an adhesive layer 6 interposed therebetween. Further, as shown in FIG. 2, a pattern printing layer 3b may be provided on the outer layer side of the glossy printing layer 3a, or as shown in FIG. 4, a pattern printing layer 3b may be provided in parallel with the glossy printing layer 3a. You may do so. Further, as shown in FIG. 3, a black background 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, a white background color printing layer 3d may be provided on the inner layer side of the glossy printing layer 3a. Although not shown, a white background printing layer 3d may be provided on the inner layer side of the glossy print layer 3a in FIGS. 1 to 3. Also, between the plastic film 2 and the glossy print layer 3a, A gas barrier layer (not shown) may be formed between the layer 3a and the sealant layer 4.
Specifically, the packaging material of the present invention can be exemplified by the following laminated structure in order from the outer layer side. Note that "/" means the boundary between 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 print layer/Gas barrier layer/Intermediate base material layer/Sealant layer Note that from the viewpoint of making the Glossy print layer 3 visible from the outside, it is formed on the outer layer side than the Glossy print layer 3a. The layer to be used shall have light transmittance.

<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 print 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, and acrylonitrile-butadiene-styrene copolymer resins. 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) Polyester resins such as polybutylene terephthalate (PBT) and polyethylene naphthalate (PEN), polyamide resins such as various nylons (Ny), polyurethane resins, acetal resins, cellulose resins, polyvinylidene chloride resins (PVDC) ) etc. The plastic film may be uniaxially stretched or biaxially stretched. Alternatively, it may be a composite film in which two or more of the above resin films are laminated. These plastic films may be formed by an inflation method or a melt extrusion coating method.

The plastic film preferably has excellent heat resistance from the viewpoint of heating in a microwave oven and retort processing. Examples of resins constituting the plastic film having excellent heat resistance include polyester resins and polyamide resins.
Specific examples of plastic films with excellent heat resistance 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 having a structure of PET/Ny/PET and PET/Ny from the outer layer side. Further, as the composite film, it is also preferable to combine one or more types of polyester film and polyamide film with one or more types of ethylene-vinyl alcohol copolymer film and polyvinylidene chloride film.

The thickness of the plastic film 2 is not particularly limited and can be set appropriately depending on the 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 printing layer>
The packaging material of the present invention has a glossy printing layer containing a glitter pigment between the plastic film and the sealant layer.
The glossy printing layer 3a may be provided on the entire surface of the packaging material, as shown in FIGS. 1 to 3, or may be provided only on a part of the packaging material, as shown in FIG. Further, as shown in FIG. 2, a pattern printing layer 3b may be provided on a part of the outer layer side of the glossy printing layer 3a. Further, as shown in FIG. 4, a glossy print layer 3a and a pattern print layer 3b may be provided in parallel at the same position in the thickness direction of the packaging material.
Furthermore, pictures such as letters, figures, symbols, patterns, patterns, etc. may be formed using the glossy printing layer 3a.

Examples of bright pigments include pearl pigments and metal scales.
Among these, pearl pigments are preferred because they can be easily made into ink without using a high boiling point solvent such as mineral spirits. Further, pearl pigments are preferable because they can easily impart microwave resistance and are less likely to change shape etc. even during high-retort treatment, making it easier to satisfy formulas (1) and (2).
To be more specific about microwave resistance, when the packaging material is processed by heat sealing, if the glitter pigment is made of metal scales, the distance between the metal scales tends to get closer to each other during heat sealing, making it difficult to package for microwave ovens. In materials, the risk of sparks caused by microwaves in microwave ovens increases. On the other hand, in the case of pearl pigments, even if the distance between the pearl pigments is close to each other during heat sealing, the above-mentioned danger does not occur during heating in a microwave oven.

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 a scale-like fine particle of mica, and has light transmittance. For this reason, 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.
In this way, although pearl pigments are mainly composed of metal oxides rather than metals themselves, they are colorants that can produce a metallic luster.

There are several types of pearl pigments, and they can be roughly divided into three types: white pearl pigments, interference pearl pigments, and colored pearl pigments.
In white pearl pigments, the mica coating layer is made of 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, so it is sensitive to almost all wavelengths of light. Because it reflects light, it appears white or silver.
In the interference pearl pigment, the mica coating layer 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, exceeding 0.15 μm. Depending on the thickness, reflected light and transmitted light change, producing various interference colors. Sometimes called iris-colored pearls.
Colored pearl pigments are chromatic, and the mica coating layer is made of a colored high refractive index material such as ferric oxide, and the white pearl pigment is further surrounded by a colored high refractive index material such as ferric oxide or other material. These include those coated with colored pigments, and those coated with a mica coating layer containing pigments and other coloring agents.

The pearl pigment may be any of the above types, but is selected from white pearl pigments and interference pearl pigments from the viewpoint of obtaining a pearl coating color that has higher brightness and gives a luxurious look when viewed from all directions. It is preferable that the pigment contains at least one kind selected from colored pearl pigments and one or more kinds selected from colored pearl pigments. The one or more types selected from white pearl pigments and interference pearl pigments are preferably white pearl pigments, and the one or more types selected from colored pearl pigments include colored pigments such as ferric oxide, etc. It is preferable to use a high refractive index material or to coat a white pearl pigment with a colored high refractive index material.
In this case, in particular, in order to obtain a deep golden luster when viewed from all directions, use a colored pearl pigment or mica coating layer around a white pearl pigment with ferric oxide. It is preferable to use a colored pearl pigment in which 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 using a combination of one or more selected from white pearl pigments and interference pearl pigments (A) and one or more selected from colored pearl pigments (B), A:B is the mass ratio, The ratio is preferably 1:0.2 to 1:20, more preferably 1:0.5 to 1:15, even 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 diameter in this specification shall mean the average value of the long diameter of arbitrary 20 particles observed with an optical microscope.

The content of the pearl pigment in the glossy printing layer is preferably 40% by mass or more and 90% by mass or less of the total solid content of the glossy printing layer, more preferably 50% by mass or more and 85% by mass or less, and even more preferably 60% by mass or less. It is not less than 80% by mass and not more than 80% by mass.
Even when added in such a large amount, pearl pigments are suitable in that they can suppress the generation of sparks and local overheating during heating in a microwave oven. Furthermore, by adding a large amount of the pearl pigment as described above, it is possible to make it difficult for the pearl pigment to flow during high-retort processing, making it easier to satisfy formulas (1) and (2).

Examples of the material of the metal scales include metals and alloys such as aluminum, gold, silver, brass, titanium, chromium, nickel, nickel-chromium, and stainless steel.
Metal scales can be obtained by, for example, (i) peeling off a metal thin film obtained by vacuum-depositing the metal or alloy onto a plastic film from the plastic film, and crushing and stirring the peeled metal thin film; (ii) using the metal or alloy mentioned above. The powder can be obtained by mixing the powder with a solvent and spreading and/or pulverizing the powder using a media stirring mill, a ball mill, an attritor, etc.

When using metal scales as the glittering pigment, the metal scales are preferably manufactured by the method (i) above from the viewpoint of easily satisfying formulas (1) and (2).
On the other hand, the metal scales produced by the method (ii) above are disadvantageous materials from the viewpoint of satisfying formulas (1) and (2). To explain this point in detail, the metal scales produced by the method (ii) above are made into a scale shape by stretching the metal powder, so wrinkles are likely to occur on the surface of the metal scales, and the metal scales are Strain has accumulated. Then, when the metal scales produced by the method (ii) above are subjected to high heat during high-retort treatment, the strain is released and the wrinkles generated on the surface are restored, resulting in a change in shape. Therefore, in the metal scales manufactured by the method (ii) above, the intensity distribution of reflected light is likely to change due to high retort treatment. In other words, the metal scales manufactured by the method (ii) above are difficult to satisfy formulas (1) and (2).

The metal scales preferably have an average length of 1 to 50 μm, more preferably 2 to 30 μm, and even more preferably 5 to 20 μm.
By setting the average length to 1 μm or more, agglomeration can be easily suppressed, and by setting the average length to 50 μm or less, when metal scales are tilted in the glossy printing layer, they are difficult to come into contact with other metal scales. can.

The metal scales preferably have an average thickness of 0.01 to 5 μm, more preferably 0.02 to 3 μm, and even more preferably 0.05 to 1 μm.
By setting the average thickness to 0.01 μm or more, it is easy to improve handleability and metallic luster, and by setting the average thickness to 5 μm or less, the metal scales are inclined in the glossy printing layer, thereby narrowing the interval between the metal scales. can be suppressed.
Further, the metal scales preferably have an aspect ratio defined by [average length/average thickness] of 50 to 500, more preferably 60 to 450, and even more preferably 70 to 400. .

The average length and average thickness of the metal scales are the average values of 20 metal scales. Note that the length and thickness of each metal scale can be measured by using a laser interference type three-dimensional shape analyzer while the metal scales are scattered on a smooth base material. The length of an individual metal scale means the maximum diameter when observing an individual metal scale from a plane in any direction, and the thickness of an individual metal scale means the maximum diameter when an individual metal scale is observed from a cross-sectional direction. Means maximum thickness. Note that the maximum diameter of each metal scale when observed from a plane in any direction is intended to unify the direction in which the maximum diameter of each metal scale is measured. For example, if the X-axis direction on the screen where the measurement results of the three-dimensional shape analyzer are image-processed is set to an arbitrary direction (measurement direction), the maximum diameter shall be measured in a direction parallel to the X-axis. Even if the maximum diameter exists in a direction that is not parallel to the X axis, it is not considered the maximum diameter.
As a laser interference type three-dimensional shape analysis device, for example, there is a product name “Shape Analysis Laser Microscope VK-X Series” manufactured by Keyence Corporation.

The content of metal scales in the glossy print layer is 3% by mass or more and less than 40% by mass of the total solid content of the glossy print layer, from the viewpoint of suppressing the generation of sparks and local overheating when heated in a microwave oven. The content is preferably 10% by mass or more and 30% by mass or less.

The glossy printing layer preferably contains 0.5% by mass or less of a black pigment.
By including a small amount of black pigment in the glossy print layer, the black pigment absorbs the light that is not reflected by the glitter pigment present near the surface layer, and suppresses diffuse reflection on the inner layer side than the glossy print layer. It is possible to improve the metallic luster.
In particular, when the glittering pigment is a pearl pigment, by including a small amount of black pigment in the glossy printing layer, the complementary color that has passed through the pearlescent pigment is suppressed from being reflected on the inner layer side of the glossy printing layer. It is possible to obtain a pearlescent color.

The content of carbon black in the glossy printing layer is preferably 0.5% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.01% by mass or less. Further, the lower limit of the carbon black content in the glossy printing layer is preferably 0.0001% by mass or more from the viewpoint of making it easier to obtain a deep pearl coating color.

Examples of the black pigment include carbon black and titanium black. Further, a black pigment having near-infrared reflective property or near-infrared transparent property, which will be described later, can also be used.

The average primary particle diameter of the black pigment is preferably 0.1 μm or more, more preferably 0.2 μm or more, from the viewpoint of increasing absorption in the visible light region. Although the upper limit of the average primary particle diameter of the black pigment is not particularly limited, it is preferably 3.0 μm or less, more preferably 2.0 μm or less, and still more preferably 1.0 μm or less.
The average primary particle diameter of the black pigment is determined as the mass average value d50 in particle size distribution measurement using a laser light diffraction method.

It is preferable that the glossy printing layer contains a coloring agent other than a black pigment in order to improve the design.
Coloring agents include general-purpose dyes and pigments (e.g., inorganic pigments such as yellow lead, titanium yellow, Bengara, cadmium red, ultramarine blue, and cobalt blue, and organic pigments or dyes such as quinacridone red, isoindolinone yellow, and phthalocyanine blue). ) can be used.

The content of the colorant is preferably 10 to 70 parts by mass, more preferably 20 to 60 parts by mass, and even more preferably 30 to 50 parts by mass, based on 100 parts by mass of metal scales. .

The glossy printing layer preferably contains inorganic particles (hereinafter sometimes referred to as "inorganic fine particles") having an average primary particle diameter of 1 to 100 nm.
By containing inorganic fine particles in the glossy print layer, it is possible to make it difficult for the glitter pigment to flow within the glossy print layer during high-retort processing, making it easier to satisfy formulas (1) and (2). . In particular, inorganic fine particles are effective when the glittering pigment is metal scales.
The average primary particle diameter of the inorganic fine particles is more preferably 2 to 50 nm, and even more preferably 5 to 30 nm. The average primary particle diameter of the inorganic fine particles is determined as the mass average value d50 in particle size distribution measurement using a laser light diffraction method.

The content of inorganic fine particles in the glossy printing layer is preferably 10 to 70 parts by weight, more preferably 15 to 50 parts by weight, and 20 to 35 parts by weight based on 100 parts by weight of the glitter pigment. It is more preferable that

Examples of the inorganic fine particles include silica, alumina, zirconia, and titania. Among these, silica is preferred because of its excellent transparency. Further, since silica and alumina have excellent insulating properties, they are preferable in that they can improve microwave resistance.

The thickness of the glossy printing layer is preferably 1 to 10 μm, more preferably 1.5 to 5 μm, from the viewpoint of sufficiently impressing metallic luster.

The glossy printing layer 3a, the pattern printing layer 3b, the black background printing layer 3c, and the white background printing layer 3d (hereinafter, these may be collectively referred to as "printing layers") are made of, for example, a plastic film. 2, the sealant layer 4, etc., 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 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 base material 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. . Furthermore, the packaging material 1 may be printed entirely or partially.

The ink of the printing layer usually has a vehicle consisting of a binder resin and a solvent as its main component, and a coloring agent such as a dye or pigment is added to this and mixed with it (the glossy printing layer 3a requires a glittering pigment. (included as an ingredient). The coloring agent for the printing layer may be used alone or in combination of two or more.

Examples of binder resins include polyolefin resins such as polyethylene resins and chlorinated polypropylene resins, poly(meth)acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, and 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 resins, unsaturated polyester resins, thermosetting poly(meth)acrylic resins, melamine resins, urea resins, polyurethane resins, phenolic resins, xylene resins, maleic acid resins, nitrocellulose, ethylcellulose, acetyl Examples include cellulose resins such as butyl cellulose and ethyloxyethyl cellulose, rubber resins such as chlorinated rubber and cyclized rubber, petroleum resins, and natural resins such as rosin and casein.

In addition, the binder resin of the glossy printing layer should have a melting point of 130°C or higher, from the viewpoint of suppressing the flow of the glitter pigment in the glossy printing layer during high retort and making it easier to satisfy formulas (1) and (2). Something is preferable.
The melting point of the binder resin of the glossy printing layer is more preferably 140°C or higher, and even more preferably 150°C or higher.
In addition, in this specification, a resin with a melting point of AA°C or higher includes not only a resin whose melting point is observed at AA°C or higher, but also a resin whose melting point is not observed at a temperature lower than AA°C or higher than AA°C. shall be held.

The printing layer forming ink may further contain fillers, stabilizers, plasticizers, antioxidants, light stabilizers such as ultraviolet absorbers, dispersants, thickeners, desiccants, lubricants, Any additives such as antistatic agents and crosslinking agents can be added.

As the solvent contained in the ink of the printing layer, solvents used in ordinary pigment inks can be used, such as methanol, ethanol, normal propanol, isopropanol, alcohol solvents such as propylene glycol monomethyl ether, acetone and methyl ethyl ketone. , ketone solvents such as methyl isobutyl ketone, ester solvents such as methyl acetate, ethyl acetate, n-propyl acetate, aliphatic hydrocarbon solvents such as n-hexane, n-heptane, and n-octane, cyclohexane, methylcyclohexane, cycloheptane, etc. Examples include alicyclic hydrocarbon solvents, aromatic solvents such as toluene and xylene, and mineral spirits. These may be used alone or in combination of two or more.
Among these, from the viewpoint of the working environment during printing, food hygiene, etc., it is preferable that aromatic solvents are not included.

In general, ink containing metal scales such as aluminum paste contains mineral spirit as a solvent, but mineral spirit has a high boiling point of 162 to 192 degrees Celsius at 1 atm, and is heated and dried after printing. Even when solvents are applied, it is difficult to completely volatilize and remove them, and even if there is only a small amount remaining, the manufactured packaging material may develop a solvent odor. It is undesirable for the packaging material to generate such a solvent odor, and in particular, when the object to be packaged by the packaging material is food, it is required that the packaging material not generate the solvent odor as much as possible.
For this reason, it is not preferable to use a high boiling point solvent such as mineral spirits as the solvent used in the ink forming the printing layer, and it is preferable that the boiling point at 1 atm is 150°C or less, more preferably 130°C or less. The temperature is preferably 120°C or lower, more preferably 120°C or lower.

<Picture printing 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 it can be formed in parallel with the glossy printing layer 3a at the same position in the thickness direction of the packaging material ( Figure 4).

The pattern printing layer 3b may be any printing layer formed of a color that can be distinguished from the glossy printing layer 3a, and is a broad concept that includes characters, figures, symbols, designs, patterns, solid printing, and the like. The coloring agent for the pattern printing layer 3b may be a general-purpose dye or pigment (for example, inorganic pigments such as yellow lead, titanium yellow, Bengara, cadmium red, ultramarine blue, cobalt blue, etc., quinacridone red, isoindolinone yellow, phthalocyanine blue, etc.). organic pigments or dyes) can be used.
The thickness of the pattern printing layer is not particularly limited, and is preferably about 1.5 to 5 μm, more preferably 1.5 to 3 μm.

<Black background printing layer>
When the glittering pigment is a pearl pigment, from the viewpoint of imparting depth and solidity to the metallic luster caused by the pearl pigment, as shown in FIG. is preferably provided.
The black background printing layer preferably has an L ^* value of 20 or less in the L ^* a ^* b ^* color system of the Commission Internationale de l'Eclairage (CIE) standard, measured in accordance with JIS Z8781-4:2013. , more preferably 10 or less.
The black background printing layer may be formed on the entire surface of the area having the glossy print layer, or may be formed only on a part of the area having the glossy print layer. When the black background printing layer is formed on the entire surface of the area having the glossy printing layer, the above-mentioned effect can be obtained on the entire surface of the glossy printing layer. Further, when a black background color printing layer is formed in a part of the area having the glossy printing layer, a change in metallic gloss can be imparted within the surface. The black background printing is preferably monochrome solid printing.

The thickness of the black background printing layer may be as long as it can highlight the metallic luster of the glossy printing layer 3a due to the pearl pigment, and is not particularly limited, and is preferably about 1.5 to 5 μm. More preferably, it is 1.5 to 3 μm.

The method for forming the black background printing layer is not particularly limited, but it can be formed by printing using the above-described printing method with ink using a black dye, pigment, or the like as a coloring agent. As the black coloring agent, it is preferable to use a black pigment from the viewpoint of developing a stable black background color.
The black pigment of the black background printing layer is preferably a black pigment that has near-infrared reflectivity or near-infrared transmittance. Examples of black pigments that reflect near-infrared rays include composite oxides containing manganese as an essential component and at least one metal element other than manganese; examples of black pigments that transmit near-infrared rays include azomethine azo. Examples include pigments, perylene pigments, and the like.

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

Azomethine azo pigments have a diazonium group that is a reaction compound of tetrachlorophthalimide and aminoaniline.
Perylene pigments are pigments having a structure in which two oxygen atoms constituting the six-membered ring of perylenetetracarboxylic dianhydride have been removed, and examples include perylene black.

The average particle size of the black pigment in the black background printing layer can be in the same range as the average particle size of the black pigment in the glossy printing layer.

The content of the black pigment in the black background printing layer is 10 to 50% by mass of the total solids constituting the black background printing layer, from the viewpoint of highlighting the metallic luster and the balance of coating film strength. The amount is preferably from 15 to 45% by weight, and even more preferably from 20 to 40% by weight.

As the black pigment for the black background printing layer, it is also possible to use a general-purpose black pigment such as carbon black or titanium black. However, with general-purpose black pigments such as carbon black and titanium black, if the packaging material 1 is for use in microwave ovens, the portion where carbon black, titanium black, etc. are present will be locally overheated by the microwaves of the microwave oven. This may cause holes in the packaging material. For this reason, when using general-purpose black pigments such as carbon black and titanium black for microwave ovens, care must be taken to suppress the content.

<White background printing layer>
As shown in FIG. 4, the packaging material of the present invention preferably has a white background printed layer 3d on the inner layer side of the glossy printed layer 3a. By forming the white background color printing layer, the appearance of the packaged item can be improved depending on the type of the packaged item. In addition, when having the above-mentioned black background color printed layer, it is preferable to form a white background color printed layer on the inner layer side than the black background color printed layer. The white background color printing layer is preferably formed by monochrome solid printing.

The white background color printing layer may be formed only on a part of the surface of the packaging material, but from the viewpoint of facilitating the above-mentioned effect, it may be formed on the entire surface of the packaging material as shown in FIG. It is preferable to form. As the coloring agent for the white background printing layer, a general-purpose white pigment can be used. Note that in order to adjust the color of the white background printing layer, dyes and pigments other than white pigments may be used as the coloring agent.
The thickness of the white background printing layer is not particularly limited, and is preferably about 1.5 to 5 μm, more preferably 1.5 to 3 μm.

<Sealant layer>
The inner layer side of the sealant layer 4 comes into direct contact with the packaged item and plays a role in protecting the packaged item. In particular, when the packaging material 1 is used to form a packaging container for a liquid, the sealant layer 4 is preferably made of a material that does not allow the liquid to penetrate. Further, it is preferable that the innermost layer of the sealant layer 4 has heat sealability for forming a pouch.

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. , propylene homopolymer, ethylene-propylene block copolymer, ethylene-propylene random copolymer, and other polyolefin resins, and one or more of these resins can be used. The sealant layer 4 may be composed of a single layer or a multilayer of two or more layers. Note that the sealant layer is preferably an unstretched film made of the resin described above in order to suppress shrinkage during heat sealing.

In order to improve heat resistance from the viewpoint of heating in a microwave oven and retort processing, the sealant layer is preferably composed of a resin with excellent heat resistance. Specifically, the sealant layer is made of a resin having excellent heat resistance. Propylene-based resins such as polymers, ethylene-propylene random copolymers, and HDPE are preferred.
Moreover, it is preferable to use the propylene-based resin properly depending on the purpose. Specifically, ethylene-propylene block copolymers are preferable when cold resistance is important (for example, packaging materials for frozen foods), and ethylene-propylene random copolymers are preferable when transparency is important. If sexiness is important, propylene homopolymer is preferred. Furthermore, in the case of a container equipped with an automatic steaming mechanism, ethylene-propylene block copolymers are preferred from the viewpoint that the seal strength decreases at high temperatures, making it easier to release steam.

Furthermore, when the packaging material 1 forms a lid of a container with a lid, the sealant layer 4 preferably has easy-peel properties.
Easy peel property refers to the property that, for example, when the sealant layer 4 of the packaging material 1 of the lid of a lidded container is bonded to the container body, the lid is easily peeled off from the container body when the lidded container is opened. say.
A sealant layer having easy peel properties is made of two or more resins, one resin (resin that has good adhesion to the container body) and another resin (resin that does not have good adhesion to the container body, and It can be formed by mixing one resin and an incompatible resin. Such resins differ depending on the material of the container, so it cannot be generalized, but if the container is made of PP, one resin (a resin with good adhesion to the container body), PP, and the other resin. By forming a sealant layer from a resin mixed with one or more selected from PE, polybutene, and polystyrene, which are resins (resins that do not have good adhesion to the container body and are incompatible with the first resin), Easy peelability can be imparted to PP containers.
Note that the sealant layer may have a multilayer structure, and easy peelability 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).

The thickness of the sealant layer 4 is not particularly limited, and is appropriately set depending on the use of the packaging material 1 and the type and properties of the packaged item, but it 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, and even more preferably 30 to 100 μm. Further, in the case of a container with a lid, the thickness of the sealant layer 4 is more preferably 15 to 80 μm, and still more preferably 20 to 60 μm.

<Gas barrier layer>
A gas barrier layer can be provided anywhere 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. Furthermore, it may also provide light-shielding properties that block 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, it is made of a light-transmitting material, similar to the plastic film 2, so that the glossy print layer 3a can be visually recognized from the outside.

The gas barrier layer can be formed as a vapor deposited film or a coated film by a known method. Note that the surface on which the gas barrier layer is to be formed may be subjected to a surface treatment 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, etc., glow discharge treatment, oxidizing agent treatment, and application of an anchor coating agent.

[Vapor deposited film]
Examples of vapor deposited films that are examples of gas barrier layers 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), or other inorganic materials or oxides thereof. Among these, when the packaging material is for use in a microwave oven, silicon oxide, aluminum oxide, magnesium oxide, etc. are used to ensure that the packaged food, etc. can be sufficiently heated in the microwave. Inorganic oxides are preferred.
Methods for forming the deposited film include, for example, physical vapor deposition (PVD) methods such as vacuum evaporation, sputtering, and ion plating, and chemical vapor deposition (CVD) methods such as plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition. Laws etc.

The thickness of the deposited film varies depending on the forming material, required gas barrier performance, etc., but is usually preferably about 5 to 200 nm, more preferably 5 to 150 nm, and even more preferably 10 to 100 nm. In the case of inorganic oxides such as silicon oxide and aluminum oxide, the thickness is preferably about 5 to 100 nm, more preferably 5 to 50 nm, and 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, has the general formula R ¹ _n M (OR ² ) _m (wherein R ¹ and R ² are organic groups having 1 to 8 carbon atoms, and M is a metal atom). n is an integer of 0 or more, m is an integer of 1 or more, and n+m is the valence of M.) at least one alkoxide represented by A coating solution obtained by polycondensing an alcohol copolymer by a sol-gel method in the presence of a sol-gel catalyst, an acid, water, and an organic solvent is applied, and the coating solution is heated at 50 to 300°C to 0. It can be formed by heat treatment for 0.05 to 60 minutes.
The coating method may be, for example, roll coating such as a gravure roll coater, spray coating, spin coating, dipping, brush coating, bar coating, applicator, or other coating means. The dry thickness of the coating film is preferably about 0.01 to 30 μm, more preferably 0.05 to 20 μm, and even more preferably 0.1 to 10 μm after one or more applications.
The gas barrier coating film is preferably formed on the surface of the deposited film from the viewpoint of improving gas barrier properties.

Considering the specific structure of the gas barrier layer, the following laminated structures (1') to (4') can be exemplified as the packaging material of the present invention in order from the outer layer side. Note that "/" means the boundary between each layer.
(1') Plastic film/deposited film/glossy print layer/sealant layer (2') Plastic film/deposited film/gas barrier coating film/gloss print layer/sealant layer (3') Plastic film/gloss print layer/deposited film / Intermediate base material layer / Sealant layer (4') Plastic film / Glossy printing layer / Gas barrier coating film / Vapor deposited film / Intermediate base material layer / Sealant layer

<Intermediate base material layer>
The intermediate base material layer may be used as necessary to improve the strength and processability of the packaging material 1, to change the texture of the packaging material, or to be used as a base material for forming other layers. This is a layer provided by Examples of the constituent material of the intermediate base layer include plastic film and paper.
In the case of a plastic film, the same one as the above-mentioned plastic film 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 given properties such as shapeability, bending resistance, and rigidity, such as high-size bleached or unbleached kraft paper, pure white roll paper, paperboard, etc. 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 even more preferably 70 to 450 g/m ² . When the packaging material 1 is used for soft 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.

In order to improve heat resistance from the viewpoint of heating in a microwave oven or retort treatment, it is preferable that the intermediate base material layer has excellent heat resistance. Specific examples of the intermediate base material layer having excellent heat resistance include the plastic films exemplified as plastic films for packaging materials for microwave ovens and retort containers, and paper.

<Adhesive layer>
In the packaging material 1, each constituent layer may be laminated with an adhesive layer 6 interposed therebetween from the viewpoint of improving the bonding strength between each layer. The adhesive layer can be formed by a method using a known dry laminating adhesive.
Examples of adhesives for dry lamination include polyvinyl acetate adhesives, polyacrylic ester 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, phenolic resin adhesives, epoxy adhesives, polyurethane adhesives (for example, cured products of polyols and isocyanate compounds), reactions Examples include (meth)acrylic acid adhesives, rubber adhesives such as chloroprene rubber, nitrile rubber, and styrene-butadiene rubber, silicone adhesives, and inorganic adhesives such as alkali metal silicates and low-melting glass.

<Thermosoftening resin layer>
As shown in FIG. 11, the packaging material 1 may have a thermosoftening resin layer 7 in a part of the area between the plastic film and the sealant layer.
As shown in FIG. 11, the thermosoftening resin layer 7 is formed in a part near the edge of the packaging material 1, and the thermosoftening resin layer has a predetermined strength in a temperature environment below room temperature. By being composed of a resin that loses a certain level of strength in a high-temperature environment, when heated in a microwave oven and the pressure inside the packaging container increases, part of the sealant layer breaks and the heat-softening resin A portion of the layer may undergo interfacial delamination or cohesive failure, allowing steam to escape. The details will be explained in the second embodiment of the automatic steaming mechanism.

Thermoplastic resins, that is, resins that have a specified strength in a temperature environment below room temperature but whose specified strength decreases in a high temperature environment, have a melting point of 60 to 110°C, preferably 60 to 90°C. Examples of resins include ethylene-vinyl acetate copolymer resins, polyamides, nitrified cotton, and polyethylene wax, and mixed resins of polyamide, nitrated cotton, and polyethylene wax are preferred. As the resin containing polyamide, nitrified cotton, and polyethylene wax, MWOP varnish (softening point: 105° C.) manufactured by DIC Graphics Corporation can be used.

The thickness of the thermosoftening resin layer is preferably 1 to 5 μm. By setting the thickness of the heat-softening resin layer to 1 μm or more, the heat-softening resin layer and the sealant layer can be easily destroyed when heated in a microwave oven. Further, by setting the thickness of the thermosoftening resin layer to 5 μm or less, when the film-like packaging material is rolled up, it is possible to suppress the formation of a bulge in a part and the stretching of the packaging material in that part.

[Packaging container]
The packaging container of the present invention is at least partially formed of the packaging material.
By forming the container with the above-mentioned packaging material, a packaging container with a high-class feel due to its metallic luster can be obtained even if metal itself is not used.
The packaging material may be applied to a desired area to give a sense of luxury due to metallic luster, and even if the entire packaging container is formed of the packaging material, or alternatively, the packaging material may be used only for a part of the packaging container. You can.

The type and use of the packaging container of the present invention are not particularly limited, but when selling the contents contained in the packaging container, the packaging container can impress the purchaser with the luxury of the contents. For example, it can be suitably used for food containers, cosmetic containers, etc.
Examples of packaging containers include pouches and containers with lids, as well as cups and trays. These packaging containers partially include the above-mentioned packaging material. That is, these packaging containers may be formed of a packaging material containing paper as an intermediate base material layer.
The specific shape of the pouch includes, for example, the shape of a microwave oven pouch shown in FIG. 5, which will be described later. Note that the pouch may be a retort container (a container sterilized at high temperature and high pressure), and may also be a packaging container for a microwave oven or a container other than a retort container.
A specific shape of the container with a lid includes a container main body having a storage part, and a lid body joined to the container body so as to seal the storage part, and the lid body Examples include those made of packaging material.
The packaging container can be suitably used in a microwave oven as described above. Moreover, the packaging container can also be used as a retort container. Of course, the packaging container can also be used as a retort container for microwave ovens.

When the packaging container is a microwave oven container or a retort container, the packaging material constituting the container preferably has a laminated structure of any one of (1) to (4) above.
In this case, as the plastic film, it is preferable to use a single polyester film, a single polyamide film such as nylon, or a composite film containing one or more types of polyester film and polyamide film.
In this case, as the intermediate base material, it is preferable to use a single polyester film, a single polyamide film such as nylon, a composite film containing one or more types of polyester film and polyamide film, and paper.
Further, in this case, as the sealant layer, propylene-based resins such as propylene homopolymer, ethylene-propylene block copolymer, ethylene-propylene random copolymer, etc., and HDPE are preferable.
More specifically, in the case of a retort container or a microwave oven container, the packaging material constituting the container preferably has a laminated structure of any one of the following (A1) to (A12). Note that "/" means the boundary between each layer. Furthermore, 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 printing layer/PET/ethylene-propylene block copolymer (A5) PET/gas barrier layer/glossy printing layer/PET/ethylene-propylene block copolymer ( A6) PET/glossy printing layer/gas barrier layer/PET/ethylene-propylene block copolymer (A7) Coextruded stretched film (PET/Ny/PET) PET/glossy printing layer/PET/ethylene-propylene block copolymer ( A8) Coextruded stretched film (PET/Ny/PET)/Gas barrier layer/Glossy printing layer/PET/Ethylene-propylene block copolymer (A9) Coextruded stretched film (PET/Ny/PET)/Glossy printed layer/Gas barrier Layer/PET/ethylene-propylene block copolymer (A10) PBT/glossy printing layer/Ny/ethylene-propylene block copolymer (A11) PBT/gas barrier layer/glossy printing layer/Ny/ethylene-propylene block copolymer (A12) PBT/glossy printing layer/gas barrier layer/Ny/ethylene-propylene block copolymer

In the case of a microwave oven container, the ethylene-propylene block copolymer that is the sealant layer (A1) to (A12) above may be a polyethylene resin such as LDPE, LLDPE, MDPE, or HDPE.
In addition, when adopting the structure of the automatic steaming mechanism of the second embodiment described later in a container for a microwave oven, the above-mentioned heat-softening resin layer must be formed in a part between the plastic film and the sealant layer. Bye.

(pouch)
FIG. 5 shows an example of a pouch that is an embodiment of the packaging container of the present invention. The pouch 10 shown in FIG. 5 is for use in a microwave oven, and is a standing type pouch formed by heat-sealing a body part 11 and a bottom part 12. As shown in FIG. 5, the body 11 includes a pair of main sheets 13 consisting of a front main sheet 13a and a back main sheet 13b arranged opposite to each other, and a pair of overlapping main surfaces. The vicinity of side edges 14 of the sheets 13 are heat-sealed to each other. A bottom sheet 16 forming the bottom portion 12 is arranged between the lower edges 15 of the pair of main sheets 13.
Then, a storage space 17 for accommodating the contents is formed in a region surrounded by the pair of main sheet 13 and bottom sheet 16. The bottom sheet 16 is bent into a convex shape toward the accommodation space 17, and the vicinity of its periphery is heat-sealed together with the lower part of the overlapping main sheet 13. Since the bottom sheet 16 maintains the shape of the lower ends of the pair of main sheets 13, the pouch 10 is given independence and can be made into a standing pouch.
In the pouch 10 of FIG. 5, an opening 19 is formed between the upper edge 18 of the front main surface sheet 13a and the back main surface sheet 13b, and the contents can be accommodated through the opening 19. After storing the contents, the packaging container can be sealed by heat-sealing the vicinity of the upper edge 18 where the opening 19 is formed. When taking out the contents from the pouch 10, the pouch 10 is opened by tearing the vicinity of the upper edge 18 from the notch 23.

The front main sheet 13a, the back main sheet 13b, and the bottom sheet 16 of this 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 pearl pigments, or only one sheet requiring metallic luster may be formed of the packaging material 1. good. FIG. 5 shows that the front main surface sheet 13a is formed of the packaging material 1 having a laminated structure as shown in FIG. 2, and has a glossy print layer 3a and a pattern print layer 3b.
Note that the sheet other than the sheet in which the packaging material 1 is used may be, for example, a sheet in which the glossy print layer 3a containing pearl pigment is not formed in the packaging material 1, or a sheet that does not include a print layer.

(Automatic steaming mechanism)
If the container is for use in a microwave oven, when the pressure inside the pouch increases due to steam generated from cooking the food, etc. inside, the steam inside the storage space is automatically released to the outside to prevent the pouch from bursting. It is preferable to have an automatic steaming mechanism. 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 shown in FIG. 5 has a first unsealed area 21 that is not heat sealed near the side edge 14 on the upper side of the container (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 side. Further, the heat seal portion 25 extends toward the accommodation space 17 so as to surround the first unsealed region 21 extending toward the accommodation space 17, forming an overhang portion 25a. More specifically, the first unsealed region 21 and the accommodation space 17 are separated from each other, and a projecting portion 25a is formed so as to be connected to a heat sealing portion 25 for sealing the pouch. .
In the microwave oven pouch shown in FIG. 5, an automatic steaming mechanism 20 is formed by the opening 22, the first unsealed area 21, and the heat-sealed part (projection part 25a) projecting toward the housing space 17 as described above. has been done. Specifically, when the pressure inside the container increases due to heating, the overhanging portion 25a of the heat seal portion 25 receives a strong load, and the overhanging region 25 peels off first. The space 17 and the first unsealed area 21 communicate with each other, allowing steam to escape to the outside.
Further details of the automatic steaming mechanism of the type shown in FIG. 5 are described in JP 2015-120550A, JP 2016-74457A, and JP 2016-74458A.

In the container 10 shown in FIG. 5, 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 in the first unsealed area 21 when a plurality of retort containers 10 are continuously formed and then cut into pieces one by one. It does not necessarily have to be formed.

A second embodiment of the automatic steaming mechanism will be described with reference to FIGS. 11 to 13.
The packaging container (pouch) 10 shown in FIG. 12 has an edge of the packaging material shown in FIG. It is made into a pouch by heat-sealing the area around it. 13 is a sectional view taken along line XI-XI of the heat-sealed portion 25 around the edge of the packaging container 10 in FIG. 12.
As shown in FIG. 12, the heat-softening resin layer 7 is formed in at least a part of the heat-sealed portion 25 of the packaging container 10, extending from the inner edge to the outer edge of the heat-sealed portion 25 for sealing the pouch. It is necessary that the The heat-softening resin layer 7 provided at such a position is heated in a microwave oven to a high temperature, thereby reducing its strength.
As shown in FIG. 13, when the heat-softening resin layer 7 is heated in a microwave oven or the like and the internal pressure increases due to the expansion of the air in the packaging container 10 or the water vapor contained in the contents, the thermoplastic resin layer 7 is A part of the sealant layer 4 is destroyed, and a 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 (the broken line with symbol B indicates the sealant (The figure shows a virtual line where the layer 4 breaks and a virtual line where the thermoplastic resin layer 7 shows interfacial peeling or cohesive failure.) As a result, air and water vapor escape from the broken portion, and the internal pressure of the packaging container 10 can be reduced.
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 constituting the container equipped with the second embodiment of the automatic steaming mechanism, it is preferable to select a resin that is easily disintegrated as the resin constituting the sealant layer. Specifically, LLDPE is preferred. Further, it is preferable that the packaging material constituting the container equipped with the second embodiment of the automatic steaming mechanism has a laminated structure of any one of the following (B1) to (B6). Note that "/" means the boundary between each layer. Furthermore, in (B1) to (B6), PET and Ny are preferably stretched films.

(B1) PET/glossy printing layer/thermosoftening resin layer/LLDPE
(B2) PET/gas barrier layer/glossy printing layer/thermosoftening resin layer/LLDPE
(B3) PET/glossy printing layer/gas barrier layer/thermosoftening resin layer/LLDPE
(B4) Ny/Glossy printing layer/Thermosoftening resin layer/LLDPE
(B5) Ny/gas barrier layer/glossy printing layer/thermosoftening resin layer/LLDPE
(B6) Ny/Glossy printing layer/Gas barrier layer/Thermosoftening resin layer/LLDPE

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

It is preferable that the lid body 33 of this lidded container 30 is formed of the packaging material 1 of the present invention. According to such a lid body 30, it is possible to create a beautiful appearance due to metallic luster, and it is also possible to provide a container with a lid that suppresses glare from reflected light under sunlight. Note that FIG. 6 shows that the lid 33 is formed of the packaging material 1 having a laminated structure as shown in FIG. 2, and has a glossy print layer 3a and a pattern print layer 3b.

The lid 33 has easy-peel properties, as described in the description of the sealant layer 4 of the packaging material 1 above, from the viewpoint of making it easier to peel off the lidded container 30 from the container body 32 and open the lidded container 30. It is preferable.
Specifically, the lid 33 and the container body 32 are joined at a joining line 35 of the flange portion 34 of the container body 32. For example, the joining line 35 may be formed by heat sealing the lid 33 and the flange portion 34, or may be formed from a separate component such as an adhesive layer.

When the lidded container 30 is used in a microwave oven, when the pressure inside the lidded container 30 increases due to steam generated by cooking the food contained in the container body 32, the lidded container 30 It is preferable to include an automatic steaming mechanism (a third embodiment of the automatic steaming mechanism) that automatically releases the steam inside the container 30 to the outside and prevents the lidded container 30 from bursting.
For example, the flange portion 34 has a protrusion 34a that protrudes toward the center of the container body 32, and the joining line 35 also has a protrusion formed in a convex shape toward the center of the container along this protrusion 34a. It has a line 35a. By forming the joining line 35 in such a form, as the pressure inside the lidded container 30 increases due to heating, the joining line 35 is likely to peel off from the protruding line 35a, and the container body 32 accommodating part 31 and the outside can be communicated with each other, and the steam inside the lidded container 30 can be released to the outside.
In the lidded container 30 shown in FIGS. 6 and 7, the protrusions 34a are formed on the opposing long sides of the flange portion 34, but two protrusions 34a are not necessarily formed. You can.

In addition, as the lid body 33 constituting the lidded container 30, a packaging material shown in FIG. 11 (a packaging material having a heat-softening resin layer in a part near the edge between the plastic film and the sealant layer) By using this, steam can be released when heated in a microwave oven for the same reason as explained in the second embodiment of the automatic steaming mechanism described above.

<Lid body>
The lid of the present invention is formed from the packaging material of the present invention described above.

It is preferable that the packaging material constituting the lid body has a laminated structure of any one of the above-mentioned (1) to (4).
In addition, when the lid is used for a microwave oven or a retort container, the plastic film may be a single polyester film, a single polyamide film such as nylon, or a composite film containing one or more types of polyester film and polyamide film. preferable.
In addition, when the lid is used for a microwave oven or a retort container, the intermediate base material layer may include a single polyester film, a single polyamide film such as nylon, a composite film containing one or more types of polyester film and polyamide film, and , it is preferable to use paper.
Further, 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 peelability as the sealant layer. Such a film varies depending on the type of container, but if the container is made of propylene resin, which is a general-purpose resin, it is preferable to use a film made of a resin mixed with PP and one or more types selected from PE, polybutene, and polystyrene. . Note that the sealant layer may have a multilayer structure, and easy peelability 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 constituting the lid preferably has one of the following laminated structures (C1) to (C11). Note that "/" means the boundary between each layer. Furthermore, in (C1) to (C11), PET and Ny are preferably stretched films.
(C1) PET/Glossy print layer/Ny/Sealant layer with easy peel properties (C2) PET/Gas barrier layer/Gloss print layer/Ny/Sealant layer with easy peel properties (C3) PET/Gloss print layer/ Gas barrier layer/Ny/Sealant layer with easy peel properties (C4) PET/Glossy printing layer/PET/Sealant layer with easy peel properties (C5) PET/Gas barrier layer/Glossy print layer/PET/Easy peel properties Sealant layer (C6) PET/Glossy printing 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 printing layer/Ny/Sealant layer with easy peel properties (C9) Ny/Glossy print layer/Gas barrier layer/Ny/Sealant layer with easy peel properties (C10) Ny/Glossy print layer/EVOH/ Sealant layer with easy peel properties (C11) Ny/EVOH/Glossy printing layer/Sealant layer with easy peel properties

In addition, when employ|adopting the structure of 2nd embodiment of the automatic vaporization mechanism mentioned above to a lid body, what is necessary is just to form the thermoplastic resin layer mentioned above in a part between a plastic film and a sealant layer.

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

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

<Golden ink 1 for glossy printing layer>
・White pearl pigment 10 parts by mass (average particle size 15 μm)
・Colored pearl pigment 20 parts by mass (colored pearl pigment whose mica coating layer is ferric oxide, average particle size 15 μm)
・Carbon black 0.001 part by mass ・Inorganic fine particles 0.1 part by mass (silica, average primary particle diameter: 20 nm)
・Binder resin 10 parts by mass (polyurethane resin, melting point 140°C)
・Solvent 1 60 parts by mass (mixed solvent of propylene glycol monomethyl ether, n-propyl acetate, ethyl acetate, and isopropanol)

[Example 2]
A packaging material was obtained in the same manner as in Example 1, except that the golden ink 1 for glossy printing layers was changed to the following golden ink 2 for glossy printing layers.

<Golden ink 2 for glossy printing layer>
・7 parts by mass of aluminum scales (non-leafing type metal scales manufactured by the method (i) in the main text of the specification)
(Average length 4μm, average thickness 0.04μm, aspect ratio 100)
・Organic yellow pigment 3 parts by mass ・Inorganic fine particles 2 parts by mass (silica, average primary particle diameter: 20 nm)
・Binder resin 20 parts by mass (polyurethane resin, melting point 140°C)
・Solvent 1 70 parts by mass (mixed solvent of propylene glycol monomethyl ether, n-propyl acetate, ethyl acetate, and isopropanol)
・Solvent 2 (mineral spirit) 7 parts by mass

[Comparative example 1]
A packaging material was obtained in the same manner as in Example 1, except that Golden Ink 1 for Glossy Print Layer was changed to Golden Ink 3 for Glossy Print Layer below.

<Golden ink 3 for glossy printing layer>
- 7 parts by mass of aluminum scales (non-leafing type metal scales manufactured by the method (ii) in the main text of the specification)
(Average length 20μm, average thickness 0.1μm, aspect ratio 200)
・Organic yellow pigment 3 parts by mass ・Inorganic fine particles 2 parts by mass (silica, average primary particle diameter: 20 nm)
・Binder resin 20 parts by mass (polyurethane resin, melting point 140°C)
・Solvent 1 70 parts by mass (mixed solvent of propylene glycol monomethyl ether, n-propyl acetate, ethyl acetate, and isopropanol)
・Solvent 2 (mineral spirit) 7 parts by mass

2. Preparation of sample 2-1. Sample A
A black plate was attached to the CPP side surface of the packaging materials of Examples 1 to 2 and Comparative Example 1 via a transparent adhesive layer, and the packaging materials of Examples 1 to 2 and Comparative Example 1, the transparent adhesive layer and Sample A was prepared in which black plates were laminated. Sample A used was one in which the refractive index difference between CPP, transparent adhesive, and black plate was within 0.05.

2-2. Sample B
A pouch having the structure shown in FIG. 5 was prepared using the packaging materials of Examples 1 and 2 and Comparative Example 1, and the pouch was sealed. The produced pouches were subjected to retort treatment (high retort treatment) at 135° C. for 30 minutes using a batch-type hot water spray sterilization tester manufactured by Hisaka Seisakusho Co., Ltd. The specifications of the test machine are shown below. In addition, a packaging material was cut out from the retort-treated pouch, and a black plate was attached to the CPP side surface of the cut-out packaging material via a transparent adhesive layer. Sample B was prepared in which a packaging material, a transparent adhesive layer, and a black plate were laminated. Sample B used was one in which the refractive index difference between CPP, transparent adhesive, and black plate was within 0.05.

<Specifications of hot water spray type sterilization tester>
・Processing amount: 20kg
・Maximum working pressure: 0.5MPa
・Maximum operating temperature: 140℃
・Wetted parts material: SUS316
・Sterilization tank dimensions: Inner diameter = 600mm, straight body part = 735mm
・Effective liquid volume: 20L
・Heating method: Hot water spray Heating/cooling method: Spray cooling ・Pressure control: Constant pressure, aeration method ・Processing mechanism: Stationary type ・Temperature raising capacity: 20 to 130℃ 11 minutes ・Temperature distribution in the tank: Within ±0.5℃・Equipment dimensions: W1,330 x L2,130 x H1,800mm
・Device weight: 1,600kg
・Utility: Steam = 150kg/h, Cooling water = 360L/1 time (2m ³ /h), Equipment power = 5.4kW

3. Measurement Set the sample prepared in 2-1 and 2-2 above in a variable-angle photometer (product number GP-200 manufactured by Murakami Color Research Institute, Inc. angle within 0.5 degrees), and Visible light rays tilted 45 degrees from the normal direction are incident on the surface of the packaging material side of the sample, and the specular reflection direction of the incident light is set as the reference angle of 0 degrees, and the range is ±15.0 degrees around the reference angle. The intensity of the reflected light was measured every 0.1 degree. At the time of measurement, the scale of the light receiving diaphragm was set to "4" and the scale of the light flux diaphragm was set to "3".
Based on the obtained reflection intensity for each angle, d ₁ (degrees), |(d ₁ - d ₂ )/d ₁ |×100 in equation (1), |(d ₃ - d ₄ in equation (2)) )/d ₃ |×100 was calculated.

4. Evaluation 4-1. Aesthetic appearance due to metallic luster The packaging materials of Examples 1 to 2 and Comparative Example 1 (packaging materials before high retort treatment) were observed from the plastic film side under indoor fluorescent lighting, and the aesthetic appearance due to metallic luster was evaluated. 20 test subjects evaluated the samples, giving 3 points for good aesthetic appearance due to metallic luster, 2 points for fair appearance, and 1 point for inferior aesthetic appearance due to metallic luster, and calculating the average score. The results are shown in Table 1.
<Evaluation criteria>
A: Average score is 2.5 or more B: Average score is 1.5 or more and less than 2.5 C: Average score is less than 1.5

4-2. Change in metallic luster (change in appearance)
Sample A and Sample B were observed from the plastic film side under indoor fluorescent light illumination, and the difference in metallic luster between the two samples was evaluated. 20 subjects evaluated the results, giving 3 points for those who did not feel a difference in the metallic luster between the two samples, 2 points for those who could not tell, and 1 point for those who felt a difference in the metallic luster between the two samples. The average score was calculated. The results are shown in Table 1.
<Evaluation criteria>
A: Average score is 2.5 or more B: Average score is 1.5 or more and less than 2.5 C: Average score is less than 1.5

From the results in Table 1, by selecting packaging materials that satisfy formula (1), it is possible to create an aesthetic appearance with metallic luster without using a metal layer, and to suppress changes in appearance during the distribution process. We can confirm that we can provide packaging materials.
In addition, in the packaging material of Comparative Example 1, the wrinkles on the surface of the metal scales were restored by the high retort treatment, the reflection intensity diffused over a wide angle decreased, and the reflection intensity near the specular reflection direction increased, so that the formula (1 ) is considered not to have been satisfied.

1 Packaging material 2 Plastic film 3a Glossy printing layer 3b Pattern printing layer 3c Black background printing layer 3d White background printing layer 4 Sealant layer 5 Intermediate base material layer 6 Adhesive layer 7 Thermosoftening resin layer 10 Packaging container 11 Body part 12 Bottom 13 Main sheet 14 Side edge 15 Lower edge 16 Bottom sheet 17 Accommodation space 18 Upper edge 19 Opening 20 Automatic vaporization mechanism 21 First unsealed area 22 Opening 23 Second unsealed area 24 Notch 25 Heat seal part 25a Output portion 30 Container with lid 31 Storage portion 32 Container body 33 Lid 34 Flange portion 35 Joining line 100 Sample

Claims (5)

A method for sorting packaging materials having a configuration in which at least a plastic film, a printing layer, and a sealant layer are laminated in this order from the outer layer side,
In the case where the printing layer has a glossy printing layer containing a glitter pigment, the angle indicating 1/2 the intensity of the reflected light in the specular reflection direction of the packaging material measured under the following measurement conditions 1 is d ₁ , When the angle indicating 1/2 of the intensity of the reflected light in the specular reflection direction of the packaging material measured under measurement condition 2 below is defined as _d2 , the passing line is defined as the one that satisfies the following formula (1). , How to sort packaging materials.
|(d ₁ - d ₂ )/d ₁ |×100 ≦ 8.0% (1)
<Measurement conditions 1>
A black plate is bonded to the surface of the packaging material on the sealant layer side via a transparent adhesive layer to produce sample A in which the packaging material, the transparent adhesive layer, and the black plate are laminated. Visible light rays inclined at 45 degrees from the normal direction of the sample A are incident on the surface of the packaging material side of the sample A, and the specular reflection direction of the incident light is set to 0 degrees of the reference angle, and the reference angle is set as the center. The intensity of the reflected light is measured every 0.1 degree within a range of ±15.0 degrees.
<Measurement conditions 2>
The packaging material is subjected to batch retort treatment at 135° C. for 30 minutes using a hot water shower type retort device to obtain a retort-treated packaging material. A black plate is bonded to the surface of the sealant layer side of the packaging material to be retorted via a transparent adhesive layer to produce sample B in which the packaging material to be retorted, the transparent adhesive layer, and the black plate are laminated. Visible light rays inclined at 45 degrees from the normal direction of the sample B are incident on the surface of the sample B on the side of the packaging material to be retorted, and the standard angle is set to 0 degrees, with the direction of specular reflection of the incident light being 0 degrees. The intensity of the reflected light is measured every 0.1 degree within a range of ±15.0 degrees from the center. The method for sorting packaging materials according to claim 1, wherein the packaging material is a microwave oven packaging material. A packaging material having a configuration in which at least a plastic film, a printing layer, and a sealant layer are laminated in this order from the outer layer side,
having a gas barrier layer between the plastic film and the printing layer,
The printing layer has a glossy printing layer containing metal scales,
d ₁ is the angle indicating 1/2 of the intensity of the reflection intensity in the specular reflection direction of the packaging material measured under measurement condition 1 below, and A packaging material that satisfies the following formula (1), where _d2 is the angle that indicates 1/2 of the strength.
3. 6 % ≦ | (d ₁ - d ₂ )/d ₁ | × 100 ≦ 8.0% (1)
<Measurement conditions 1>
A black plate is bonded to the surface of the packaging material on the sealant layer side via a transparent adhesive layer to produce sample A in which the packaging material, the transparent adhesive layer, and the black plate are laminated. A visible light beam tilted by 45 degrees from the normal direction of the sample A is incident on the surface of the packaging material side of the sample A, and the direction of specular reflection of the incident light is set to 0 degrees of the reference angle, and the reference angle is set as the center. The intensity of the reflected light is measured every 0.1 degree within a range of ±15.0 degrees.
<Measurement conditions 2>
A packaging material to be retorted is obtained by retorting the packaging material at 135° C. for 30 minutes in a batch-type hot water shower type retort device. A black plate is bonded to the surface of the sealant layer side of the packaging material to be retorted via a transparent adhesive layer to produce sample B in which the packaging material to be retorted, the transparent adhesive layer, and the black plate are laminated. Visible light rays inclined at 45 degrees from the normal direction of the sample B are incident on the surface of the sample B on the side of the packaging material to be retorted, and the standard angle is set to 0 degrees, with the direction of specular reflection of the incident light being 0 degrees. The intensity of the reflected light is measured every 0.1 degree within a range of ±15.0 degrees from the center. A retort container at least partially formed of the packaging material according to claim 3. The retort container according to claim 4, which is for use in a microwave oven.