JP2023031191A - shrink film and container - Google Patents

Abstract

To provide a shrink film having high light-shielding properties and good appearance.SOLUTION: A shrink film 1 includes: a substrate 10 that shrinks when heated; a design layer 20 formed on the first surface 10a of the substrate 10; a gloss layer 30 formed on the design layer 20 and having a metallic luster; a white layer 40 formed on the gloss layer 30; and a black layer 50 formed on the white layer 40.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a shrink film, and more particularly to a light-shielding shrink film that shields contents. Reference is also made to the container to which this shrink film is attached.

Shrink films made of synthetic resin are known as means for easily applying patterns, letters, etc. to containers. When the shrink film is placed around the container and heated, the shrink film shrinks and adheres to the outer surface of the container.

When the contents to be stored in a container deteriorate due to light, they are stored in a light-shielding container. limit the

If the laminate to be the shrink film has a light-shielding property, the light-shielding property can be imparted even to a transparent container by attaching it.
Patent Document 1 describes a heat-shrinkable film imparted with a light-shielding property as a related prior art. A shielding layer made of white ink is provided on one side of the heat-shrinkable film, and a shielding layer containing an aluminum pigment is provided on the opposite side.

Japanese Patent No. 6620526

When the heat-shrinkable film described in Patent Literature 1 is attached to a container, a design layer is formed on the shielding layer with the shielding layer side facing the outer surface and having patterns, characters, and the like.
Therefore, there is a possibility that patterns and characters may be damaged during the distribution process after manufacturing, or the light-shielding property may be deteriorated. In addition, since the design layer is printed on the outside of the heat-shrinkable film, the color tone reproducibility may be lowered.
Furthermore, it is necessary to select a film having both sides corona-treated in order to apply ink to both sides of the heat-shrinkable film, which narrows the choices of film materials.

An object of the present invention is to provide a shrink film having a high light-shielding property and a good appearance.

A first aspect of the present invention includes a substrate that shrinks when heated, a design layer formed on the first surface of the substrate, a gloss layer having metallic luster formed on the design layer, and a gloss layer on the gloss layer. and a black layer formed on the white layer.

A second aspect of the present invention is a container having the shrink film according to the first aspect attached on the outer surface in a shrunk state.

The shrink film according to the present invention has a high light-shielding property and hardly causes damage to patterns, characters, and the like.

1 is a schematic cross-sectional view showing the layer structure of a shrink film according to one embodiment of the present invention; FIG. It is a graph which shows the result of having examined the usefulness of the layered structure which concerns on this invention.

One embodiment of the present invention will be described with reference to FIG.
FIG. 1 is a schematic cross-sectional view showing the layer structure of a shrink film 1 according to this embodiment. The shrink film 1 includes a base material 10 made of synthetic resin, and a design layer 20, a gloss layer 30, a white layer 40, and a black layer 50 which are sequentially formed on the base material 10. FIG.
The design layer 20, the glossy layer 30, the white layer 40, and the black layer 50 are all formed on the first surface 10a side of the substrate 10, and the printed layer is not formed on the opposite second surface 10b side. not

The substrate 10 may be any material as long as it shrinks when heated, and a stretched film can be suitably used. Examples of materials for the base material 10 include polystyrene, polyethylene terephthalate, polyolefin, polypropylene, and acrylic resin. The thermal contraction rate of the base material 10 can be appropriately set in consideration of the applied container and the like.
The substrate 10 may be colorless and transparent, or may be colored as long as the design layer 20 can be visually recognized from the second surface 10b side. The thickness of the base material 10 can also be appropriately set, and can be, for example, about 10 to 70 μm.

The design layer 20 is a layer formed by single-color or multi-color printing, and presents an appearance in which characters, figures, patterns, etc. are used singly or in combination. The mode of the design layer 20 can be appropriately set according to the contents of the container to which the shrink film 1 is attached, and is not particularly limited.
The design layer 20 does not have to be formed on the entire surface of the substrate 10 . On the first surface 10 a , the base material 10 is exposed on the portion where the design layer 20 is not formed, and the glossy layer 30 is formed on the exposed base material 10 .

The glossy layer 30 is a layer having metallic luster, and exhibits light shielding properties by reflecting light incident from the second surface 10b side. Furthermore, the appearance of the attached container can be enhanced by giving it a metallic luster.
The glossy layer 30 can be formed by printing an ink containing metal powder or flakes. Aluminum is preferred as the metal, but other metals may be used. When aluminum is used, the glossy layer 30 exhibits a silver color.

The white layer 40 can be formed by printing white ink over the entire surface. The white layer 40 may be pure white, or may contain pigments of other colors to the extent that the white-based appearance of the layer as a whole is not significantly impaired.
Examples of the white pigment contained in the white ink include titanium oxide, calcium carbonate, magnesium carbonate, and the like, and these can be used alone or in combination.

The black layer 50 can be formed by printing black ink over the entire surface. The black layer 50 may be pure black, or may contain other color pigments to the extent that the overall black appearance of the layer is not significantly impaired.

In the shrink film 1 of the present embodiment having the above configuration, the design layer 20 is formed on the first surface 10a of the base material 10, and then the glossy layer 30, the white layer 40, and the black layer 50 are sequentially printed over the entire surface. can be formed by Various known methods can be used for printing, and gravure printing, offset printing, letterpress printing, silk screen printing, transfer printing and the like can be exemplified.

When the completed shrink film 1 is adhered to form a cylindrical shape with the first surface 10a side inside, and is placed around the body of the container and heated, the base material 10 shrinks and adheres to the container, resulting in the formation of the container. Can be mounted on an exterior surface. In this state, the second surface 10b of the shrink film constitutes the outermost surface of the container, and the design, display, etc. of the design layer 20 can be visually recognized through the substrate 10. FIG.

Although the shrink film 1 is in close contact with the container, it is not joined, so it can move relative to the container. The metal powder and metal flakes contained in the glossy layer 30 are easily peeled off by friction caused by relative movement. Also, when the shrink film 1 is thermally shrunk, the metal powder and metal flakes contained in the glossy layer 30 may peel off.
In the shrink film 1 of the present embodiment, the white layer 40 and the black layer 50 formed on the glossy layer 30 suitably protect the glossy layer 30, thereby suppressing such peeling. As a result, the light-shielding property exhibited by the glossy layer can be maintained satisfactorily for a long period of time.

Due to its structure, it is difficult for the glossy layer 30 to completely reflect incident light, and part of the incident light is transmitted through the glossy layer 30 .
Since the shrink film 1 has the black layer 50 on the glossy layer 30, most of the light transmitted through the glossy layer 30 is absorbed by the black layer 50 and does not reach the container. As a result, the shrink film exhibits high light shielding properties as a whole.

The inventors paid attention to the synergistic effect of the gloss layer and the black layer described above, and first examined a configuration in which the black layer was provided directly on the gloss layer. As a result, it was found that while the expected light-shielding property was obtained, the appearance of the glossy layer when viewed from the second surface 10b side was dull.
Since the gloss layer 30 is formed on the design layer 20 , it also functions as a ground color for the design displayed by the design layer 20 . Therefore, there was concern that the appearance of the container to which the shrink film 1 was attached could not be kept sufficiently good due to the dull appearance of the glossy layer.

The inventors solved this by providing a white layer between the gloss layer and the black layer. That is, by forming the white layer 40 on the glossy layer 30 and forming the black layer 50 thereon, the generation of dullness due to the black layer 50 is suppressed, and the gloss layer 30 when viewed from the side of the second surface 10b. I managed to keep it looking good.
Furthermore, since part of the light transmitted through the glossy layer 30 is reflected by the white layer 40 before reaching the black layer 50, the effect of further improving the light shielding property is also obtained compared to the structure without the white layer. . The inventors also tried a shrink film in which only a white layer was formed on the glossy layer, but the light-shielding property was insufficient and the desired performance was not satisfied.

As described above, the shrink film according to the present embodiment has a good appearance while having a high light-shielding property, and is suitable for use in enhancing the design while imparting a light-shielding property to a container.
Furthermore, since the design layer 20 is not provided on the second surface 10b side, it does not come into contact with or rub against surrounding articles during the distribution process or the like, so that its appearance is favorably maintained.

The usefulness of the layer structure according to this case will be explained with reference to data.
Samples 1 and 2 shown below were prepared.
(Sample 1)
Base material: transparent resin film (thickness 50 μm)
Glossy layer: full-surface printing of ink containing aluminum (thickness less than 1 μm)
White layer: white ink (SVF (K-19) series, manufactured by Dainichiseika Kogyo Co., Ltd.) full-surface printing (thickness less than 1 μm)
Black layer: full-surface printing of black ink (SVF (K-19) series, manufactured by Dainichiseika Kogyo Co., Ltd.) (thickness less than 1 μm)
(Sample 2)
Having the same configuration as Sample 1, except that it does not have a black layer

Using Samples 1 and 2, the light transmittance in the wavelength range of 200 nm to 1100 nm was measured according to JIS K 7105. Two measurements were performed for each sample, and the results of plotting the average values are shown in FIG.
Looking at FIG. 2, in the ultraviolet region with a wavelength of 380 nm or less, there is no significant difference in the light shielding properties between Sample 1 and Sample 2. exhibits sufficient light shielding properties even in the visible light region with a wavelength of about 380 nm to 780 nm.
The shrink film according to the present invention can be expected to favorably suppress deterioration of contents by applying it to packaging, even for contents that are damaged not only by ultraviolet light but also by visible light.

Although one embodiment of the present invention has been described, the specific configuration is not limited to this embodiment, and modifications and combinations of configurations are also included within the scope of the present invention.

For example, the method for forming the glossy layer is not limited to the above-described method, and may be formed by vapor deposition or the like.

The contents of the container to which the shrink film according to the present invention is attached are not particularly limited, and can be widely applied to foods, medicines, various materials, etc., as long as they benefit from light shielding.

1 shrink film 10 base material 10a first surface 20 design layer 30 glossy layer 40 white layer 50 black layer

Claims (3)

a base material that shrinks when heated;
a design layer formed on the first surface of the substrate;
a gloss layer formed on the design layer and having a metallic luster;
a white layer formed on the glossy layer;
a black layer formed on the white layer;
comprising a
shrink film. wherein the glossy layer is silver
The shrink film of Claim 1. The shrink film of claim 1 or 2 is attached on the outer surface in a shrunk state.
container.

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