JP7437110B2 - Metal-like packaging materials and packaging containers - Google Patents

Description

The present invention relates to a metallic packaging material and a packaging container using the same.

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 a means for imparting metallic luster, for example, it is generally practiced to form a metal layer such as a metal vapor deposition film or metal foil on a base material.
In addition, in order to eliminate the drawbacks (cost, microwave resistance) of metal layers such as metal vapor deposited films and metal foils, a glossy layer is formed with an ink containing aluminum paste at a predetermined concentration as a means of imparting metallic luster. A means has also been proposed (Patent Document 1).

On the other hand, in order to reduce the gloss of the surface of the packaging material and improve the feel of the packaging material, a packaging material in which a matte layer is formed on the surface has been proposed (Patent Document 2).

JP 2017-81589 Publication Japanese Patent Application Publication No. 2004-345136

Packaging materials equipped with a metallic luster layer such as a metallic deposited film, a metallic foil, and a lustrous layer formed from the aluminum paste of Patent Document 1 can all produce an aesthetic appearance due to the metallic luster and can improve the design. However, packaging materials provided with a metallic luster layer have too strong a metallic luster and give a dull impression, and are therefore not preferred in some cases.

In order to solve this problem, it is possible to form a matte layer as described in Patent Document 2 on the surface of a packaging material provided with a metallic luster layer to soften the metallic luster.
However, when a packaging material is made by forming a matte layer on the surface of a packaging material with a metallic luster layer, when the surface is rubbed with a finger or the like, traces of the abrasion become extremely noticeable, and there are cases where the design quality is significantly reduced. It was seen here and there.

In order to solve the above problems, the present invention aims to provide a metal-like packaging material that does not leave noticeable traces of scratches even when the surface is scratched and can suppress deterioration in design, and a packaging container using the same. purpose.

That is, the present invention provides the following [1] to [2].
[1] Comprising a matte layer, a transparent base material, a metallic luster layer, and a sealant layer in this order from the outer layer side, the surface of the matte layer measured at a cutoff value of 0.8 mm in accordance with JIS B0601:1994. A metallic packaging material in which the maximum height Ry and the arithmetic mean roughness Ra of the surface of the mat layer measured at a cutoff value of 0.8 mm in accordance with JIS B0601:1994 satisfy the relationship of the following formula (1). .
5.0≦Ry/Ra≦8.5 (1)
[2] A packaging container formed of the metallic packaging material according to [1] above.

Even when the surface of the metal-like packaging material of the present invention and the packaging container using the same are scratched, traces of scratches are not noticeable, and deterioration in design can be suppressed.

1 is a schematic cross-sectional view showing an embodiment of a metallic packaging material of the present invention. It is a schematic sectional view showing other embodiments of the metal-like packaging material of the present invention.

Hereinafter, the metal-like packaging material of the present invention and the packaging container using the same will be explained. 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."

[Metallic packaging material]
The metallic packaging material of the present invention has a matte layer, a transparent base material, a metallic luster layer, and a sealant layer in this order from the outer layer side, and is measured at a cutoff value of 0.8 mm in accordance with JIS B0601:1994. The relationship between the maximum height Ry of the mat layer surface and the arithmetic mean roughness Ra of the mat layer surface measured at a cutoff value of 0.8 mm in accordance with JIS B0601:1994 is expressed by the following formula (1). It is something that satisfies.
5.0≦Ry/Ra≦8.5 (1)

FIGS. 1 and 2 are schematic cross-sectional views showing examples of the laminated structure of the metallic packaging material 10 of the present invention.
In FIGS. 1 and 2, the upper side is the outer layer side (front side), and the lower side is the inner layer side (back side). The metallic packaging material 10 of the present invention has a matte layer 20, a transparent base material 30, a metallic luster layer 40, and a sealant layer 50 in this order, as shown in FIGS. 1 and 2.
Moreover, in FIG. 1, the matte layer 20 and the metallic gloss layer 40 are formed on the entire surface of the packaging material, but in FIG. 2, the matte layer 20 and the metallic luster layer 40 are formed on a part of the packaging material.

The laminated structure of the metallic packaging material 10 may include other layers as constituent layers.
For example, the metallic packaging material 10 shown in FIGS. 1 and 2 includes a pattern layer 60.

<Surface shape>
The metallic packaging material of the present invention has a maximum height Ry of the mat layer surface measured with a cutoff value of 0.8 mm in accordance with JIS B0601:1994, and a cutoff value of 0.8 mm in accordance with JIS B0601:1994. It is necessary that the arithmetic mean roughness Ra of the surface of the matte layer measured in 1 satisfies the relationship of the following formula (1).
5.0≦Ry/Ra≦8.5 (1)

The arithmetic mean roughness Ra is a parameter indicating the average of the absolute values in the height direction in the reference length. On the other hand, the maximum height Ry is a parameter indicating the sum of the maximum value of the peak height of the contour curve at the reference length and the maximum value of the valley depth of the contour curve at the reference length.
Therefore, it can be said that "Ry/Ra" in equation (1) indicates the degree of protrusion of the highest convex portion with respect to the average roughness of the mat layer within the reference length.

If Ry/Ra is less than 5.0, the degree of protrusion of the highest convex portion is insufficient, and when the surface of the mat layer is rubbed with fingers, etc., the fingers are likely to come into contact with the surface of the mat layer. The area of the layer surface that is rubbed increases. Further, normally, the protruding parts of the mat layer are formed of particles and are not easily damaged, but the non-protruding parts are formed of a binder resin that is softer than the particles and therefore tend to be easily damaged. Therefore, when Ry/Ra is less than 5.0, fingers and the like tend to come into contact with the soft binder resin, and are easily damaged when the mat layer surface is rubbed.
On the other hand, if Ry/Ra exceeds 8.5, it means that the arithmetic mean roughness Ra is small (≒ roughness is insufficient in areas other than the highest altitude) and/or the maximum height Ry is large. It means. Therefore, if Ry/Ra exceeds 8.5, a finger or the like that has climbed over the highest convex part may easily come into contact with the surface of the mat layer that is insufficiently rough, and in that case, the surface of the mat layer may be scratched. The area covered will increase. In addition, if Ry/Ra exceeds 8.5, the load from a contact object such as a finger may tend to concentrate on the highest convex part, and in that case, the convex part may easily fall off. The surface of the mat layer becomes easily damaged.

As described above, by satisfying formula (1), it is possible to reduce the contact area of a finger or the like to the surface of the mat layer, and to suppress damage to the surface of the mat layer.
When the matte layer surface is rubbed with fingers etc., if the matte layer is deformed due to pressure, the matte layer surface is damaged, or dirt such as sebum adheres to the matte layer surface, the optical properties of the matte layer at the scratched location may be Characteristics change. In packaging materials that simply have a matte layer, changes in the optical properties of the matte layer are not so noticeable. However, in packaging materials that have a matte layer on a metallic gloss layer, if the optical properties of the matte layer at the scratched area change, the appearance of the metallic gloss layer changes greatly between the scratched area and the non-rubbed area. The traces are extremely noticeable and the design quality is significantly reduced.
In the metal-like packaging material of the present invention, since the matte layer satisfies formula (1), when the surface of the matte layer is rubbed with a finger etc., the change in optical properties as described above can be suppressed. However, the deterioration of the design can be suppressed without noticeable scratch marks. That is, the combination of the metallic luster layer and the matte layer satisfying formula (1) in the metallic packaging material of the present invention can be said to be an extremely useful combination.

Note that by satisfying formula (1), it is possible to reduce the contact area of a finger or the like to the surface of the mat layer, thereby making it difficult for stains such as fingerprints to adhere. In addition, when formula (1) is satisfied, even if dirt such as fingerprints adheres to the mat layer, the adhered dirt does not penetrate into the details of the mat layer surface and gathers near the highest convex part, and the dirt Since the amount of adhesion is small, it is easy to remove adhering dirt.

In formula (1), Ry/Ra is preferably 5.5 or more and 8.0 or less, more preferably 6.0 or more and 7.5 or less.
In this specification, Ry, Ra, and S are average values measured at a total of 50 locations, 25 locations in the machine direction (MD) and 25 locations in the direction perpendicular to the MD direction (TD) on the surface of the mat layer.

In addition, as a means for improving the scratch resistance of the surface of the matte layer, the following means (A) and (B) are generally considered.
(A) Increase the crosslinking density of the binder resin in the matte layer to increase the hardness of the matte layer.
(B) A slip agent is added to the mat layer to make the surface of the mat layer slippery.
However, in the case of the method (A), cracks tend to occur in the mat layer during processing and distribution. In particular, when the packaging material is a soft packaging material, if the mat layer is too hard, the mat layer is likely to crack when wrinkles occur in the packaging material.
Furthermore, in the case of the method (B), when producing the packaging material (particularly when winding it up), the slip agent is transferred to the surface of the mat layer, making it difficult to form into a pouch.
Therefore, it is extremely important in the field of packaging materials to improve the abrasion resistance of the mat layer surface by using the structure of the present invention without adopting the general means such as (A) and (B) above. It can be said to be useful.

It is preferable that the arithmetic mean roughness Ra of the surface of the mat layer satisfies the relationship of the following formula (2).
0.30μm≦Ra≦1.00μm (2)

By setting Ra of the surface of the mat layer to 0.30 μm or more, the texture of the metallic packaging material can be easily improved. Further, by setting Ra of the surface of the matte layer to 0.30 μm or more, the metallic luster of the metallic luster layer that is visually recognized through the matte layer is weakened, and a calm design can be easily achieved. In addition, by setting the Ra of the surface of the matte layer to 0.30 μm or more, when the matte layer is partially formed (particularly in the part with the metallic luster layer, the part with the matte layer and the part with the matte layer) (when forming a matte layer with or without a matte layer), it is possible to easily improve the contrast in design depending on the presence or absence of a matte layer.
Further, by setting Ra of the surface of the mat layer to 1.00 μm or less, it is possible to easily suppress deterioration in design due to whitening of the surface of the metallic packaging material. Further, by setting Ra of the surface of the matte layer to 1.00 μm or less, it is possible to easily suppress the loss of the metallic luster of the metallic luster layer that is visually recognized through the matte layer.
Ra of the mat layer surface is more preferably 0.50 μm or more and 0.90 μm or less, and even more preferably 0.60 μm or more and 0.80 μm or less.

Ry on the surface of the mat layer is preferably 3.00 μm or more and 7.00 μm or less, more preferably 4.00 μm or more and 5.50 μm or less.

Further, the local peak spacing S on the surface of the mat layer measured at a cutoff value of 0.8 mm in accordance with JIS B0601:1994 is preferably 18 μm or more, more preferably 20 μm or more, and 22 μm or more. It is even more preferable that there be.
By setting S on the surface of the mat layer to 18 μm or more, it becomes difficult for dirt to enter into the fine irregularities, making it easier to improve dirt removability.
The upper limit of S on the surface of the matte layer is not particularly limited, but the upper limit is preferably 50 μm, more preferably 40 μm, and even more preferably 30 μm.

<Matt layer>
The matte layer is formed on at least a portion of the outer layer side of the transparent base material.
Further, the matte layer is preferably formed at a position where the matte layer overlaps at least a portion of the area having the metallic luster layer when the metallic packaging material is viewed from above. By arranging the matte layer so as to overlap with at least a portion of the location having the metallic luster layer in the planar direction, the effects of the present invention can be significantly exhibited.
Note that the matte layer may be arranged so as to overlap in the planar direction all the areas having the metallic luster layer, but from the viewpoint of expressing the contrast of metallic luster depending on the presence or absence of the matte layer, It is preferable to arrange it so that it overlaps with a part of.

The matte layer may be formed without containing particles by, for example, pouring resin into a mold, but from the viewpoint of scratch resistance, one containing a binder resin and particles is preferable.

<<particles>>
As the particles, one or more types selected from organic particles and inorganic particles can be used.
Examples of organic particles include particles made of polymethyl methacrylate, polyacrylic-styrene copolymer, melamine resin, polycarbonate, polystyrene, polyvinyl chloride, benzoguanamine-melamine-formaldehyde condensate, silicone, fluorine resin, polyester resin, etc. Can be mentioned.
Examples of the inorganic particles include particles made of silica, alumina, antimony, zirconia, titania, and the like.
Among these, inorganic particles are preferred because they tend to improve scratch resistance. Also, among the inorganic particles, silica is preferred because it easily suppresses whitening of the matte layer.

The inorganic particles are preferably inorganic particles whose surfaces have been subjected to hydrophobization treatment. By hydrophobicizing the surface of the inorganic particles, aggregation of the inorganic particles can be suppressed within the mat layer, making it easier to satisfy the above formula (1). Furthermore, when particles agglomerate within the mat layer, voids are created between the particles, and these voids disappear during rubbing, which can make scratch marks more noticeable. However, by suppressing particle aggregation, , this phenomenon can be suppressed.
Note that inorganic particles whose surfaces have been subjected to hydrophobization treatment have a reaction product between a functional group on the surface of the inorganic particles and a surface treatment agent on the surface of the inorganic particles. Examples of functional groups on the surface of inorganic particles include silanol groups of silica particles.

Surface treatment agents include trimethylsilyl chloride, dimethyldichlorosilane, trimethylsilyltrifluoromethanesulfonate, chloromethyltrimethylsilane, hexamethyldisilazane, triethylsilane, triethylsilyl chloride, triisopropylsilyl chloride, t-butyldimethylsilane, t-butyl Examples include one or more selected from dimethylsilyl chloride, octylsilane, hexadecylsilane, allyltrimethylsilane, trimethylvinylsilane, aminosilane, methacrylsilane, polydimethylsiloxane, and the like.

The average particle diameter of the particles is preferably 0.1 to 15.0 μm, more preferably 1.0 to 10.0 μm, even more preferably 2.0 to 7.5 μm, and even more preferably 2.7 μm. It is even more preferable that the thickness is 5.0 μm.
In this specification, the average particle diameter of particles is measured as a mass average value d50 in particle size distribution measurement using a laser light diffraction method.

Moreover, it is preferable that the particles include two types of particles having different average particle diameters. That is, it is preferable that the matte layer contains a binder resin and two types of particles having different average particle diameters.
By including two types of particles with different average particle diameters, it is possible to impart an appropriate Ra to the particles with a small average particle diameter, while also imparting an appropriate Ry to the particles with a large average particle diameter, and the formula ( 1) can be easily satisfied.
Note that three or more types of particles may be included as long as the effects of the present invention are not impaired.

Of the two types of particles having different average particle diameters, the particles with the larger average particle diameter are preferably inorganic particles from the viewpoint of scratch resistance, and more preferably silica from the viewpoint of suppressing whitening of the matte layer. Further, both of the two types of particles having different average particle diameters are preferably inorganic particles, and more preferably silica.
Further, it is preferable that at least one of the two types of particles having different average particle diameters is an inorganic particle whose surface has been subjected to a hydrophobization treatment, and it is more preferable that both of them are inorganic particles whose surfaces have been subjected to a hydrophobization treatment.

Among the two types of particles with different average particle diameters, when the average particle diameter of the particle with the larger average particle diameter is D ₁ and the average thickness of the matte layer is T, 2.0≦D ₁ /T≦5. It is preferable that the relationship of 0 is satisfied.
By setting D ₁ /T to 2.0 or more and 5.0 or less, formula (1) can be easily satisfied. Further, by setting D ₁ /T to 5.0 or less, it is possible to suppress particles having a large particle size from falling off.
D ₁ /T is more preferably 2.2 or more and 4.0 or less, and even more preferably 2.5 or more and 3.5 or less.

Furthermore, when the average particle diameter of the particle with the smaller average particle diameter is set as D ₂ among two types of particles with different average particle diameters, it is possible to satisfy the relationship 0.9≦D ₂ /T≦2.0. preferable.
By setting D ₂ /T to 0.9 or more and 2.0 or less, formulas (1) and (2) can be easily satisfied. D ₂ /T is more preferably 1.0 or more and 1.8 or less, and even more preferably 1.3 or more and 1.7 or less.

Further, the difference in particle size (D ₁ - _{D 2} ) between particles with a large average particle size and particles with a small average particle size is preferably 2.0 μm or more and 5.0 μm or less, and 2.2 μm or more and 4. It is more preferably 0 μm or less, and even more preferably 2.5 μm or more and 3.5 μm or less.

The content of particles in the mat layer is preferably 1 to 100 parts by weight, more preferably 3 to 50 parts by weight, and preferably 5 to 20 parts by weight based on 100 parts by weight of the binder resin. More preferred.
By setting the content of particles to 1 part by mass or more, it is possible to easily improve the design property based on the matte feel. Further, by controlling the content of particles to 100 parts by mass or less, it is possible to easily improve the binding properties of particles in the mat layer.

When the particles include two types of particles with different average particle sizes, the mass ratio of particles with a large average particle size and particles with a small average particle size is preferably 80:20: to 20:80, and 70 :30 to 30:70 is more preferable, and even more preferably 60:40 to 40:60.
By using two types of particles with different average particle diameters in the above mass ratio, formulas (1) and (2) can be easily satisfied.

The thickness of the matte layer is preferably 1.0 to 10.0 μm, more preferably 1.2 to 5.0 μm, and even more preferably 1.5 to 2.5 μm.
By setting the thickness of the matte layer to 1.0 μm or more, it is possible to improve the binding properties of the particles and easily improve the scratch resistance. Moreover, by setting the thickness of the matte layer to 10.0 μm or less, it is possible to suppress the visibility of the metallic luster layer and the pattern layer from decreasing.

<<Binder resin>>
As the binder resin for the mat layer, general-purpose thermoplastic resins and curable resins can be used, and curable resins are preferred from the viewpoint of scratch resistance. Examples of the curable resin include ionizing radiation curable resins and thermosetting resins. Ionizing radiation-curable resins can harden the matte layer and improve scratch resistance, but if the matte layer is made too hard, the matte layer is likely to crack during processing or distribution, so thermosetting resins is preferred. In particular, when the transparent base material is flexible such as plastic film or transparent paper, if the mat layer is too hard, the mat layer is likely to crack when wrinkles occur in the packaging material. It is preferable to use a curable resin.

As the thermosetting resin, it is preferable to use a two-component curing resin from the viewpoint of enabling the coating liquid to be used for a long time. As the two-component curable resin, a two-component curable resin of polyol and isocyanate is preferred.

Examples of polyols include acrylic polyols, polyester polyols, epoxy polyols, etc. Among these, acrylic polyols are preferred. Examples of acrylic polyols include vinyl chloride-modified acrylic polyol, vinyl chloride-vinyl acetate-modified acrylic polyol, chlorinated polyolefin-modified acrylic polyol, methyl (meth)acrylate-2-hydroxyethyl (meth)acrylate copolymer, and octyl (meth)acrylate. -Ethylhexyl (meth)acrylate-2-hydroxyethyl (meth)acrylate copolymer, methyl (meth)acrylate-butyl (meth)acrylate-2-hydroxyethyl (meth)acrylate-styrene copolymer, etc. Among these, vinyl chloride modified acrylic polyol is preferred.

Furthermore, known compounds can be used as the isocyanate. For example, aromatic isocyanates such as 2,4-tolylene diisocyanate (abbreviation: TDI), naphthalene diisocyanate, and 4,4'-diphenylmethane diisocyanate; 1,6-hexamethylene diisocyanate (abbreviation: HMDI), isophorone diisocyanate (abbreviation: IPDI) ), methylene diisocyanate (abbreviation: MDI), xylylene diisocyanate (abbreviation: XDI), hydrogenated tolylene diisocyanate; aliphatic or alicyclic isocyanate such as hydrogenated diphenylmethane diisocyanate. Also included are adducts or multimers of these isocyanates, such as TDI adducts of trimethylpropane and TDI trimers.

The matte layer may contain stabilizers, plasticizers, antioxidants, light stabilizers such as ultraviolet absorbers, dispersants, thickeners, desiccants, antistatic agents, etc., to the extent that they do not impede the effects of the present invention. Optional additives can be added.
As described above, when the mat layer contains a slip agent, the slip agent is transferred to the surface of the mat layer during production of the packaging material (particularly during winding), making it difficult to form into a pouch. For this reason, it is preferable that the mat layer does not substantially contain a slip agent. "Substantially free" means that the total solid content of the matte layer is 1% by mass or less, preferably 0.1% by mass or less, more preferably 0.01% by mass or less, and even more preferably 0% by mass. %.

The matte layer can be formed on the transparent substrate, for example, by printing using a matte layer ink containing a binder resin, particles, and the like. Examples of printing methods include gravure printing, offset printing, letterpress printing, and silk screen printing. Among these, gravure printing is preferred.

<Transparent base material>
The transparent base material is made of a light-transmitting material so that the metallic luster layer can be visually recognized from the outer layer side. For example, examples of the light-transmissive base material include plastic films, transparent papers, etc., and among them, plastic films are preferably used.

The thickness of the transparent base material is not particularly limited and can be set appropriately depending on the use of the metallic packaging material, but it is usually preferably about 5 to 50 μm, more preferably 8 to 40 μm. , more preferably 10 to 25 μm

The transparent base material preferably has a total light transmittance of 85% or more, more preferably 90% or more according to JIS K7361-1:1997. Further, the transparent base material preferably has a haze of JIS K7136:2000 of 1.0% or less, more preferably 0.5% or less, and even more preferably 0.3% or less.

Specific examples of plastic film materials include polyolefin resins such as polyethylene (PE) and polypropylene (PP), cyclic polyolefin resins, polystyrene resins, acrylonitrile-styrene copolymer (AS) resins, and acrylonitrile. - Butadiene-styrene copolymer (ABS) resin, poly(meth)acrylic resin, polycarbonate resin, polyvinyl alcohol resin, ethylene-vinyl alcohol copolymer (EVOH), saponified ethylene-vinyl ester copolymer, Polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN), polyamide resins such as various nylons (Ny), polyurethane resins, acetal resins, cellulose resins, polychloride Examples include vinylidene resin (PVDC). Among these, polyolefin resins are preferred from the viewpoint of versatility, and polyester resins and polyamide resins are preferred from the viewpoints of heat resistance, strength, etc.
The plastic film may be uniaxially stretched or biaxially stretched. Alternatively, it may be a composite film in which films of two or more of the above resins are laminated. The plastic film may also be formed by an inflation method or alternatively by a melt extrusion coating method.

When the metal-like packaging material is used for microwave ovens or retort containers, it is preferable that the plastic film has excellent heat resistance. Examples of resins constituting the plastic film with excellent heat resistance include polyester resins and polyamide resins.
Specific examples of plastic films for metal-like packaging materials for microwave ovens and retort containers include single polyester films, single polyamide films such as nylon, and composite films containing one or more of polyester films and polyamide films. Examples of the composite film include a coextruded stretched film 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 of a polyester film and a polyamide film with one or more of an ethylene-vinyl alcohol copolymer film and a polyvinylidene chloride film.

<Metallic luster layer>
Examples of the metallic luster layer include metal layers such as metal vapor deposited films and metal foils, as well as layers printed using ink containing glitter pigments (hereinafter sometimes referred to as "glitter printed layer"). can be mentioned. Examples of bright pigments include pearl pigments and metal scales.
When the metallic packaging material is used as a packaging material for a microwave oven, the metallic luster layer is preferably a glitter printing layer. Among the glittering printed layers, when giving priority to metallic luster, it is preferable to use a layer printed using ink containing metallic scales (metallic scale layer), and when giving priority to microwave resistance. In this case, a layer (pearl layer) printed using ink containing a pearl pigment is preferable.
When the metallic packaging material is used as a packaging material other than for microwave ovens, the metallic luster layer is preferably a metal layer from the viewpoint of imparting high metallic luster and from the viewpoint of gas barrier properties.

The metal vapor deposition film is made of inorganic materials such as aluminum (Al), magnesium (Mg), tin (Sn), titanium (Ti), lead (Pb), zirconium (Zr), yttrium (Y), or one of these oxides. Using the above as raw materials, it is formed by 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, thermochemical vapor deposition, and photochemical vapor deposition. be able to.
The metal vapor deposited film may be formed on the transparent base material, but it may also be formed by first forming the metal vapor deposit film on the intermediate base material and bonding it to the transparent base material. The thickness of the metal vapor deposited film is usually about 5 to 500 nm.
Examples of the metal foil include aluminum. The thickness of the metal foil is usually about 4 to 12 μm.

Examples of pearl pigments include white pearl pigments, interference pearl pigments, and colored pearl pigments.
A white pearl pigment is obtained by covering a scale-like base material such as mica, aluminum, or glass with a coating layer made of a colorless high refractive index material such as titanium dioxide, and the thickness of the coating layer is 0.1 to 0. It is relatively small at about 15 μm and reflects almost all wavelengths of light, so it appears white or silver.
In the interference pearl pigment, the 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 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 colored material. There are those coated with pigments, and those with pigments and other coloring agents added to the coating layer.

The particle size of the pearl pigment is not particularly limited, and the average length is preferably 5 to 60 μm, more preferably 5 to 30 μm.
The average length of the pearl pigment and the average length of the metal scales are the average lengths of any 20 particles (pearl pigments or metal scales) observed using an optical microscope or an electron microscope from the plane direction of the metallic packaging material. It is required as. Note that the length of one pearl pigment and metal scale means the maximum length of one pearl pigment and metal scale in the plane direction.
The content of the pearl pigment in the glitter print layer is preferably 40 to 90% by mass of the total solid content of the glitter print layer, from the viewpoint of increasing coating strength while imparting a sufficient metallic luster. More preferably 50 to 85% by weight, still more preferably 60 to 80% by weight.

Examples of metal scales include metals and alloys such as aluminum, gold, silver, brass, titanium, chromium, nickel, nickel-chromium, and stainless steel.
Metal scales include, for example, those obtained by vacuum-depositing the metal or alloy on a plastic film, peeling the metal thin film from the plastic film, crushing and stirring the peeled metal thin film, or powder of the metal or alloy. and a solvent, and spread and/or crush the powder using a media stirring mill, ball mill, attritor, etc., or those whose surfaces are coated with a resin can be used. can.

From the viewpoint of uniform dispersibility in the glitter printing layer, the metal scales preferably have an average length of 1 to 50 μm, more preferably 2 to 30 μm, and still more preferably 5 to 20 μm. In addition, from the viewpoint of ease of handling and obtaining high metallic luster, the average thickness is preferably 0.01 to 5 μm, more preferably 0.02 to 3 μm, and even more preferably 0.05 to 1 μm. Further, the aspect ratio (average length/average thickness) of the metal scales is preferably 15 to 500.
The average thickness of the metal scales and pearl pigments is determined as the average value of 20 arbitrary particles (pearl pigments or metal scales) obtained by observing the cross section of the metallic packaging material using an optical microscope or an electron microscope. The thickness of one pearl pigment or metal scale is determined by dividing the cross-sectional image of one pearl pigment or metal scale into five regions of equal length in the length direction, and calculating the thickness of the central part of each region ( t ₁ , t ₂ , t ₃ , t ₄ , t ₅ ) and mean the average of t ₁ to t ₅ .

The content of metal scales in the glitter print layer is 3% by mass or more and less than 40% by mass of the total solid content of the glitter print layer, from the viewpoint of imparting sufficient metallic luster and good microwave resistance. It is preferably 10 to 30% by mass, more preferably 10 to 30% by mass.

Examples of the binder resin for the glitter printing layer include polyolefin resins such as polyethylene resins and chlorinated polypropylene resins, poly(meth)acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, and vinyl chloride resins. Vinyl acetate copolymer, polystyrene resin, styrene-butadiene copolymer, vinylidene fluoride resin, polyvinyl alcohol resin, polyvinyl acetal resin, polyvinyl butyral resin, polybutadiene resin, polyester resin, polyamide resin, Alkyd resin, epoxy resin, unsaturated polyester resin, thermosetting poly(meth)acrylic resin, melamine resin, urea resin, polyurethane resin, phenolic resin, xylene resin, maleic acid resin, nitro resin Examples include cellulose resins such as cellulose, ethyl cellulose, acetyl butyl cellulose, and ethyloxyethyl cellulose, rubber resins such as chlorinated rubber and cyclized rubber, petroleum resins, natural resins such as rosin, and casein. These may be used alone or in combination of two or more.

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

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

<Sealant layer>
As shown in FIGS. 1 and 2, a sealant layer 50 is laminated on the inner layer side of the metallic packaging material.
The sealant layer is formed as the innermost layer of the metal-like packaging material, and the surface of the inner layer comes into contact with the packaged item to protect the packaged item. In particular, the sealant layer is used when the metal-like packaging material is used for packaging containers for liquids. When formed, the sealant layer preferably has permeation resistance to liquid substances. Further, when the airtight container is formed of a metallic packaging material, it is preferable that the sealant layer is heat-sealed to ensure airtightness. The sealant layer may be a single layer or may be a multilayer of two or more layers.

The total thickness of the sealant layer is not particularly limited, and is appropriately set depending on the use of the metallic packaging material and the type and properties of the packaged object, but it is usually preferably about 10 to 200 μm. . When a pouch (particularly a retort pouch) is formed from a metallic packaging material, the thickness of the sealant layer is more preferably 20 to 150 μm, and even more preferably 30 to 100 μm. Further, when the lid is formed of a metallic packaging material, the total thickness of the sealant layer is more preferably 15 to 80 μm, and even more preferably 20 to 60 μm.

Examples of materials constituting the sealant layer include low density PE (LDPE), linear low density PE (LLDPE), medium density PE (MDPE), high density PE (HDPE), ethylene-vinyl acetate copolymer, Examples include polyolefin resins such as propylene homopolymer, ethylene-propylene block copolymer, and ethylene-propylene random copolymer, and one or more of these resins can be used.

The sealant layer is preferably an unstretched film made of the resin described above from the viewpoint of suppressing shrinkage during heat sealing.
In addition, from the viewpoint of heat resistance during microwave heating and retort processing, the sealant layer is made of, for example, PP resin such as propylene homopolymer, ethylene-propylene block copolymer, ethylene-propylene random copolymer, HDPE, etc. It is preferable to use a resin having excellent heat resistance. It is preferable to use different PP resins depending on the purpose; for example, if freezing resistance is important, use ethylene-propylene block copolymer, or if transparency is important, use ethylene-propylene random copolymer. Furthermore, when heat resistance is important, a propylene homopolymer is preferred. In addition, when a packaging container equipped with an automatic steaming mechanism for microwave ovens is formed using metal-like packaging materials, the sealing strength of the sealant layer decreases at high temperatures, and from the viewpoint of making it easier for steam to escape from the packaging container. Ethylene-propylene block copolymers are preferred.

Further, when the lid is formed of a metallic packaging material, it is preferable that the sealant layer has easy-peel properties. Easy-peel property is, for example, a property of a lid that is joined to the container body so as to seal the accommodating portion of the container body that it is easy to peel off when the lid is peeled from the container body and opened. be.
The sealant layer having easy-peel properties can be formed using two or more resins, specifically, one resin that has good adhesion to the container body and one resin that has good adhesion to the container body. It can be formed by mixing another resin that is not compatible with the first resin and is incompatible with the first resin. For example, when the container body is made of polypropylene, the sealant layer is preferably formed of a mixed resin of a polypropylene homopolymer as the first resin and another resin such as polyethylene, polybutene, or polystyrene. In addition, when the sealant layer has a multilayer structure, it is sufficient that only the innermost layer of the sealant layer, which is joined to the container body, has easy-peel properties.

<Other layers>
The metallic packaging material of the present invention may have layers other than the above-mentioned matte layer, transparent base material, metal reflective layer, and sealant layer.

<<Picture layer>>
The metallic packaging material 10 may further include a pattern layer 60, as shown in FIGS. 1 and 2.
In order to improve the visibility of the pattern, the pattern layer 60 is located on the outer side of the metallic gloss layer 40 in the thickness direction of the metallic packaging material 10, as shown in FIG. 1, or as shown in FIG. As shown, it is preferable to form it at the same position as the metallic luster layer 40 in the thickness direction of the metallic packaging material 10.

The metallic reflective layer that is visible through the pattern layer has a reduced metallic luster. Therefore, if the pattern layer is located on the outer layer side of the metal reflective layer in the thickness direction of the metal-like packaging material, when the metal-like packaging material is viewed from above, the pattern layer overlaps all the areas where the metal reflective layer is located. It is preferable to avoid this.

The picture layer is a broad concept that includes, for example, characters (product name, product display, quality display, etc.), figures, photographs, symbols, patterns, patterns, and the like. The pattern layer may be composed of one layer, or may be composed of two or more layers.
The total thickness of the pattern layer is not particularly limited, but it is usually preferably about 1 to 10 μm, more preferably 1.5 to 5 μm.

The pattern layer is usually formed by printing using an ink containing a vehicle consisting of a binder resin and a solvent as a main component, to which a coloring agent such as a dye or a pigment is mixed. Examples of printing methods include gravure printing, offset printing, letterpress printing, and silk screen printing. Among these, gravure printing is preferred.

Coloring agents for the pattern layer include general-purpose dyes and pigments (for example, yellow lead, titanium yellow, Bengara, cadmium red, ultramarine blue, cobalt blue, carbon black, titanium black, calcium carbonate, lead white, zinc white, titanium white). (inorganic pigments such as quinacridone red, isoindolinone yellow, phthalocyanine blue, etc.) can be used.

<<Clear layer>>
A clear layer may be provided on a portion of the matte layer. Such a configuration is preferable because a difference in gloss occurs between a portion having a clear layer and a portion not having a clear layer, and the design can be improved.
The thickness of the clear layer is preferably about 0.5 to 15 μm, more preferably 1 to 10 μm, and still more preferably 2 to 7 μm.

The clear layer can be formed by coating the surface of the matte layer with, for example, gloss varnish (OP varnish). Such partial coating can be performed, for example, by gravure printing, offset printing, letterpress printing, flexo printing, silk screen printing. Among these, gravure printing and flexographic printing are preferred.

As the gloss varnish, either water-based varnish or oil-based varnish can be used.
As the water-based varnish, for example, one in which a resin component such as poly(meth)acrylic resin or (meth)acrylic-styrene copolymer is dissolved or dispersed in water and a small amount of volatile organic solvent can be used. . Examples of the volatile solvent include alcohols such as methanol, ethanol, normal propanol, isopropanol, and propylene glycol monomethyl ether, acetone, methyl ethyl ketone, and ethyl acetate.
As an oil-based varnish, for example, a resin component such as a polyurethane resin, vinyl chloride-vinyl acetate copolymer, poly(meth)acrylic resin, or chlorinated polypropylene resin is dissolved or dispersed in a volatile organic solvent. can be used. Examples of volatile solvents include methyl ethyl ketone, toluene, ethanol, and isopropanol.
Additives such as lubricants and surfactants can be added to the water-based varnish and the oil-based varnish, if necessary. The resin component in the water-based varnish and the oil-based varnish is preferably 40 to 85% by mass.

＜＜Base color printing layer＞＞
The background color printing layer is formed as necessary from the viewpoint of blocking the transmission of light from the outer layer side to the packaged object and adjusting the color tone. The background color printing layer is preferably formed between the metallic gloss layer and the sealant layer.
The background color printing layer can be formed using the same method as the pattern layer described above.
The ground color printing layer may be formed on the entire inner layer side of the metallic gloss layer, or may be formed on a part of the inner layer side of the metallic gloss layer. The total thickness of the background color printing layer is preferably about 1.5 to 5 μm, more preferably 1.5 to 3 μm.

The background color printing layer preferably includes at least one of a black background color layer and a white background color layer. Further, from the viewpoint of printing efficiency, etc., it is preferable that the ground color printing layer is a single color solid printing. Note that the ground color printing layer visible from the outer layer side of the portion not having the metallic luster layer or the pattern layer may be visually recognized as characters, figures, symbols, designs, patterns, etc.

<<Intermediate base material>>
The intermediate base material can be provided between the transparent base material and the sealant layer, for example.
The intermediate base material is provided as necessary to improve the strength and processing suitability of the metallic packaging material, and as a base material for forming other layers (metal deposited layer as a metallic luster layer, gas barrier layer, etc.). It will be done.
Examples of the intermediate base material include a plastic film. Specifically, the same material as the transparent base material can be used as the constituent material of the plastic film as the intermediate base material.

The thickness of the intermediate base material is preferably about 1 to 50 μm, more preferably 2 to 40 μm, and even more preferably 3 to 30 μm.

<<Gas barrier layer>>
When the metallic luster layer is a glitter print layer, it preferably has a gas barrier layer.
The gas barrier layer is preferably formed between the transparent base material and the sealant layer, and more preferably between the metallic luster layer and the sealant layer.

The gas barrier layer blocks the permeation of oxygen, water vapor, etc. between the object to be packaged by the metal-like packaging material and the external environment of the metal-like packaging material. Furthermore, it may also provide a light-shielding property that blocks transmission of visible light, ultraviolet rays, and the like. The gas barrier layer may be composed of one layer or may be composed of two or more layers. The gas barrier layer can be made of a known material, such as aluminum foil or a plastic film (intermediate base material) with a vapor deposited film or a coating film formed on the surface. When forming a coating film, it is preferably formed on the surface of the deposited film from the viewpoint of improving gas barrier properties.
Note that the surface of the plastic film may be subjected to a surface treatment in advance from the viewpoint of improving the adhesion of a vapor deposited film or a coating film. 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.

The vapor deposited film can be formed of, for example, inorganic substances such as silicon, aluminum, magnesium, calcium, potassium, tin, sodium, boron, titanium, lead, zirconium, and yttrium, or oxides thereof.
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 film 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.

The coating film may be formed by, for example, 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, M is a metal atom, and n is 0 or more. An integer, m represents an integer of 1 or more, and n+m is the valence of M.), and a polyvinyl alcohol resin and/or an ethylene-vinyl alcohol copolymer, - Coating solution obtained by polycondensation by sol-gel method in the presence of gel method catalyst, acid, water and organic solvent is applied and heat treated at 50-300°C for 0.05-60 minutes. It can be formed by
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.

<<Adhesive layer>>
Each constituent layer of the metal-like packaging material may be laminated with an adhesive layer interposed therebetween from the viewpoint of improving the bonding strength between each layer.
The thickness of each adhesive layer is preferably about 0.01 to 20 μm, more preferably 0.05 to 15 μm, and still more preferably 0.1 to 10 μm.

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 polyol and isocyanate), reactive type 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.

[Packaging container]
The packaging container of the present invention is formed from the metal-like packaging material of the present invention described above.
Examples of packaging containers include pouches and containers with lids, as well as cups and trays.
In the case of a container with a lid, the container body may be formed of the metal-like packaging material of the invention, or the lid, which is joined to the container body so as to seal the accommodating portion of the container body, may be formed of the metal-like packaging material of the invention. It may be formed by

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 metal-like packaging material [Example 1]
On a part of the inner layer side (back surface) of a transparent substrate (biaxially stretched PET film, thickness 15 μm), a pattern layer ink having the following formulation was back printed by gravure printing to form a pattern layer with a thickness of 1.0 μm.
Next, a matte layer ink having the following formulation was gravure printed on the entire outer layer side (surface) of the transparent substrate to form a matte layer with a thickness of 2.0 μm.
Next, vapor-deposited PET with an aluminum vapor-deposited film on one side of a PET film having a thickness of 12 μm is prepared, and the surface of the vapor-deposited PET with the aluminum vapor-deposited film and a pattern layer of a transparent base material on which a matte layer and a pattern layer are formed are prepared. A laminate was obtained by bonding the side surfaces together with a dry laminating adhesive (polyurethane adhesive).
Next, the 12 μm thick PET film side of the laminate and the sealant layer (100 μm thick polyethylene film (manufactured by Dai Nippon Printing Co., Ltd., trade name DP-402)) were bonded together using a dry laminating adhesive (polyurethane). The metal-like packaging material of Example 1 was obtained.
The laminated structure of the obtained metallic packaging material from the outer layer side is: matte layer (thickness 2.0 μm)/transparent base material (thickness 15 μm)/partial pattern layer (thickness 1.0 μm)/adhesive layer. (thickness: 3.0 μm)/metallic gloss layer (aluminum vapor deposited with a thickness of 50 nm)/plastic film layer (PET with a thickness of 12 μm)/adhesive layer (3.0 μm)/sealant layer (100 μm).

The details of the constituent materials of each layer and the ink formulation are shown below.
<Ink for pattern layer>
・Organic red pigment: 3 parts by mass ・Anti-settling agent (fine particle silica): 2 parts by mass ・Binder resin (polyurethane resin): 20 parts by mass ・Solvent 1 (mineral spirit): 7 parts by mass ・Solvent 2 (propylene glycol) Mixed solvent of monomethyl ether, n-propyl acetate, ethyl acetate, isopropanol): 70 parts by mass

<Ink for matte layer>
・Hydrophobized silica particles (average particle size 3.0 μm): 6 parts by mass ・Hydrophobized silica particles (average particle size 6.0 μm): 6 parts by mass ・Binder resin (two-component curing polyurethane of polyol and isocyanate) Resin): 100 parts by mass / Solvent (n-propyl acetate, ethyl acetate): Appropriate amount

[Examples 2 to 5], [Comparative Examples 1 to 4]
Example 2 was carried out in the same manner as in Example 1, except that the average particle diameter of the silica particles in the matte layer ink, the content of silica particles in the matte layer, and the thickness of the matte layer were changed to the conditions shown in Table 1. -5 and Comparative Examples 1 to 4 were obtained.

2. Measurement and evaluation 2-1. Surface shape The surface roughness of the outer layer side (surface) of the mat layer of each packaging material produced in Examples and Comparative Examples was measured according to JIS B0601:1994 under the following conditions, and the roughness was measured at a cutoff value of 0.8 mm. The arithmetic mean roughness Ra, maximum height Ry, and average local peak spacing S were measured. Measurements were made at a total of 50 locations, 25 locations in the flow direction (MD) and 25 locations in the direction perpendicular to the MD direction (TD), and the average values of the 50 locations were calculated as Ra, Ry, and It was set as S. The results are shown in Table 1.
<Measurement conditions>
・Measuring equipment: Surface roughness measuring machine, “Surfcom 130A” manufactured by Tokyo Seimitsu Co., Ltd.
・Reference length: Roughness curve cutoff value λc = 0.8mm
・Measurement speed: 0.15mm/s
・Measurement range: 400μm

2-2. Scratch Resistance When the outer layer side (surface) of the matte layer of each of the packaging materials produced in Examples and Comparative Examples was lightly scratched with a fingernail, whether or not traces of scratching were noticeable was visually evaluated based on the following criteria.
A: The scratch marks were not noticeable and the design was maintained.
C: Scratch marks were formed on the matte layer, and as a result, the appearance of the metallic luster layer was different between the scratched areas and the non-rubbed areas, resulting in a decrease in design.

2-3. Dirt (fingerprint) adhesion When touching the outer layer side (surface) of the matte layer of each packaging material produced in Examples and Comparative Examples with the pad of your finger, visually check whether fingerprints are noticeable according to the following criteria. It was evaluated by
A: Fingerprints are not noticeable.
C: The attached fingerprints are clearly visible.

2-4. Stain Removal Property A commercially available shampoo stock solution was dropped onto the outer layer side (surface) of the matte layer of each of the packaging materials produced in Examples and Comparative Examples, and then washed with running water for 10 seconds. The surface condition of the matte layer after washing was visually confirmed and evaluated according to the following criteria.
A: Shampoo has been removed from the matte layer.
C: Shampoo undiluted solution remains on the fine irregularities of the matte layer.

From the results shown in Table 1, it can be confirmed that even when the surface of the metallic packaging materials of Examples 1 to 5 is scratched, the scratch marks are not noticeable and deterioration in design can be suppressed. Furthermore, it can be confirmed that the metal-like packaging materials of Examples 1 to 5 have excellent dirt adhesion and removability.

10: Metallic packaging material 20: Matte layer 30: Transparent base material 40: Metallic gloss layer 50: Sealant layer 60: Pattern layer

Claims (8)

It has a matte layer, a transparent base material, a metallic luster layer and a sealant layer in this order from the outer layer side,
The mat layer has a single layer structure,
The matte layer includes a binder resin and two types of particles having different average particle sizes, and the average particle size of the two types of particles is 0.1 μm or more and 15.0 μm or less,
The maximum height Ry of the mat layer surface measured with a cutoff value of 0.8 mm in accordance with JIS B0601:1994, and the maximum height Ry of the mat layer surface measured with a cutoff value of 0.8 mm in accordance with JIS B0601:1994. A metallic packaging material whose arithmetic mean roughness Ra satisfies the relationship of formula (1) below, and whose Ra is 0.30 μm or more and 1.00 μm or less.
5.0≦Ry/Ra≦8.5 (1) The metallic packaging material according to claim 1, wherein Ry is 3.00 μm or more and 7.00 μm or less. The metal-like packaging material according to claim 1 or 2 , wherein among the two types of particles having different average particle sizes, the particles having a larger average particle size are inorganic particles. The metallic packaging material according to claim 3 , wherein the inorganic particles are silica. Among the two types of particles having different average particle diameters, when the average particle diameter of the particle with the larger average particle diameter is D ₁ and the average thickness of the matte layer is T, 2.0≦D ₁ /T≦5. The metallic packaging material according to any one of claims 1 to 4 , which satisfies the relationship of .0. The metal tone according to any one of claims 1 to 5 , wherein a local peak interval S on the surface of the matte layer measured at a cutoff value of 0.8 mm in accordance with JIS B0601:1994 is 20 μm or more and 30 μm or less. packaging material. The metallic packaging material according to any one of claims 1 to 6 , further comprising a pattern layer. A packaging container formed from the metallic packaging material according to any one of claims 1 to 7 .