WO2023145640A1 - Light-shielding laminate - Google Patents

Abstract

Provided is a light-shielding laminate with which it is possible to improve the shielding properties from light from the outside of the light-shielding laminate, and improve the aesthetic appearance of a light-shielding laminate.　The light-shielding laminate 10 includes a substrate 11, a shielding layer 13 on the substrate 11, and a light-shielding layer 12 located between the substrate 11 and the shielding layer 13 or on the opposite side of the substrate 11 from the shielding layer 13 The light-shielding layer 12 includes aluminum and titanium oxide As the shielding layer 13, for example, a white ink layer can be used.

Description

Light-shielding laminate

The present disclosure relates to a light shielding laminate.

Conventionally, the outer surface of a container for storing articles such as various foods and drinks, chemical products, cosmetics, and pharmaceuticals is exposed to light from the outside of the container from the viewpoint of protecting the quality of the contents and extending the storage period. A light-shielding laminate is sometimes attached for the purpose of blocking penetration into the interior of the container.

For example, Patent Document 1 discloses a light-shielding laminate comprising at least a pattern printed layer made of printing ink, a shielding layer, a transparent substrate layer, and a light-shielding layer, wherein the shielding layer is a single layer made of white ink. Alternatively, it is a printed layer having two or more layers, the white ink has a mass blending ratio of the white pigment and the binder resin of white pigment: binder resin = 4 to 5: 1 to 0.8, and the shielding layer is positioned on one side of the substrate layer, the light shielding layer is positioned on the opposite side of the shielding layer across the substrate layer, and the substrate layer is made of a heat-shrinkable film, After heat shrinking, in the part of the laminate where the pattern printed layer is not provided, the lightness L* value of the L*a*b* color system measured from the side opposite to the side of the base layer provided with the light shielding layer is 82 or more. A light-shielding laminate is described.

Japanese Patent No. 6620526

As in the light-shielding laminate described in Patent Document 1, in the conventional light-shielding laminate, the light-shielding layer containing aluminum particles is generally formed from the outside of the light-shielding laminate (outside the container) to the shielding layer and the substrate. It is provided to prevent light transmitted through the material layer from reaching the inside (inside the container).

However, in the conventional light-shielding laminate, due to the silvery tint of the light-shielding layer containing aluminum particles, the appearance of the light-shielding laminate becomes dark, and the appearance of the light-shielding laminate is impaired. something happened. In addition, for example, in a beverage containing vitamins, light in the visible light range (light with a wavelength of about 380 nm to 780 nm, hereinafter simply referred to as "light") is emitted from the outside of the container containing the beverage. Since the vitamins in the beverage are destroyed when they reach the beverage inside, it is sometimes important for the light-shielding laminate attached to the container to have a light-shielding property against the light.

According to embodiments disclosed herein, comprising a substrate, a shielding layer on the substrate, and a light shielding layer located between the substrate and the shielding layer or on the opposite side of the substrate from the shielding layer. , the light-shielding layer can provide a light-shielding laminate containing aluminum and titanium oxide.

According to the embodiments disclosed herein, a light-shielding laminate is provided that can improve the light-shielding property of the light-shielding laminate from the outside of the light-shielding laminate and improve the appearance of the light-shielding laminate. can do.

1 is a schematic cross-sectional view of an example of a light-shielding laminate according to Embodiment 1. FIG. 4 is a schematic cross-sectional view of another example of the light-shielding laminate according to Embodiment 1. FIG. FIG. 4 is a schematic side view of an example of a cylindrical light-shielding laminate. 1 is a schematic cross-sectional view of an example of a cylindrical light-shielding laminate described in Patent Document 1. FIG. FIG. 3 is a schematic cross-sectional view of another example of the cylindrical light-shielding laminate described in Patent Document 1; 1 is a schematic cross-sectional view of an example of a cylindrical light-shielding laminate according to Embodiment 1. FIG. FIG. 5 is a schematic cross-sectional view of an example of a light-shielding laminate according to Embodiment 2; FIG. 5 is a schematic cross-sectional view of a modification of the light-shielding laminate according to Embodiment 2; FIG. 8 is a schematic cross-sectional view of another example of the light-shielding laminate according to Embodiment 2; FIG. 10 is a schematic cross-sectional view of another modification of the light-shielding laminate according to Embodiment 2; FIG. 4 is a schematic cross-sectional view of light-shielding laminates of Experimental Examples 2 to 10. FIG. 4 shows the measurement results of the total light transmittance [%] for light with a wavelength of 250 nm or more and 800 nm or less for each of the light-shielding laminates of Experimental Examples 1 to 11. FIG.

The embodiment will be described below. In the drawings used for describing the embodiments, the same reference numerals denote the same or corresponding parts.

[Embodiment 1]
<Light-shielding laminate>
FIG. 1 shows a schematic cross-sectional view of an example of the light-shielding laminate according to Embodiment 1. As shown in FIG. As shown in FIG. 1, the light-shielding laminate 10 according to Embodiment 1 includes a substrate 11, a light-shielding layer 12 on the surface 11a of the substrate 11, a shielding layer 13 on the light-shielding layer 12, and a shielding layer 13 and an upper design printing layer 14 . In the light-shielding laminate 10 according to Embodiment 1, the light-shielding layer 12 and the shielding layer 13 are positioned on the same side of the substrate 11 .

In this specification, “the light-shielding layer 12 and the light-shielding layer 13 are positioned on the same side of the substrate 11” means that the light-shielding layer 12 and the light-shielding layer 12 and the light-shielding layer 13 are positioned on at least one of the front surface 11a and the back surface 11b of the substrate 11 on the same side. This means that both shielding layers 13 are located. In addition, in the light-shielding laminate 10 according to Embodiment 1, the light-shielding layer 12 is positioned between the base material 11 and the shielding layer 13 .

Further, the light-shielding laminate 10 according to Embodiment 1 further includes a surface protective layer 17 covering the shielding layer 13 and the design printed layer 14 on the shielding layer 13 . Further, the light-shielding laminate 10 according to Embodiment 1 further includes a slipperiness imparting layer 16 on the back surface 11b of the base material 11 .

<Base material>
The substrate 11 is a substrate containing a resin having a front surface 11 a and a back surface 11 b and capable of supporting the light shielding layer 12 and the shielding layer 13 .

Examples of the resin contained in the base material 11 include polyester-based resins (polyethylene terephthalate, polyethylene naphthalate, polylactic acid, etc.), polystyrene-based resins (polystyrene, styrene-butadiene copolymer, etc.), polyolefin-based resins (polyethylene, polypropylene, etc.). etc.), polyvinyl chloride-based resin, polyamide-based resin (nylon, etc.), aramid-based resin, polyimide-based resin, polyphenylene sulfide-based resin, acrylic resin, or the like can be used. The base material 11 may contain one type of these resins, or may contain two or more types thereof.

The base material 11 may be, for example, a heat-shrinkable plastic film (shrink film). When the substrate 11 is a shrink film, the light-shielding laminate 10 can be used, for example, as a shrink label that can be attached to the outer surface of a container or as an overwrap package. Also, the base material 11 may be, for example, a transparent plastic film or an opaque white film.

The substrate 11 may be a monolayer film consisting of one layer, or may be a multilayer film consisting of two or more layers. Also, the thickness of the base material 11 can be, for example, 5 μm or more and 150 μm or less, preferably 5 μm or more and 120 μm or less, and more preferably 5 μm or more and 100 μm or less. When the base material 11 is a multilayer film, each film constituting the base material 11 may contain different resins.

<Shielding layer>
The shielding layer 13 is a layer made of one or more layers of printing ink for the purpose of shielding the tint of the light shielding layer 12 when the light shielding laminate 10 is viewed from the outside. The thickness of the shielding layer 13 can be, for example, 0.5 μm or more and 10 μm or less.

As the shielding layer 13, for example, a white ink layer containing a white pigment and a binder resin can be used. As the white pigment, for example, titanium oxide, calcium carbonate, magnesium carbonate, or a mixture of two or more of these can be used. The binder resin for the white ink layer forming the shielding layer 13 includes, for example, acrylic resin, urethane resin, acrylic-urethane resin, cellulose resin (nitrocellulose resin, cellulose acetate butyrate resin, cellulose acetate propionate resin, etc.), or these. can be used. As the binder resin for the white ink layer that constitutes the shielding layer 13, a binder resin made of urethane resin and acrylic resin can be particularly used.

The white pigment content in the shielding layer 13 can be, for example, 60% by weight or more and 80% by weight or less of the white ink layer constituting the shielding layer 13 . When the content of the white pigment in the shielding layer 13 is 60% by weight or more of the white ink layer, the shielding property of the shielding layer 13 tends to be improved. When the content of the white pigment in the shielding layer 13 is 80% by weight or less of the white ink layer, there is a tendency that adhesion, scratch resistance and rubbing resistance can be maintained. Further, when there is no problem with adhesion, scratch resistance and rubbing resistance, the higher the white density, the more the label design looks good. % or less.

<Design printing layer>
The design printing layer 14 is a layer made of printing ink for the purpose of applying decorations such as letters, symbols, figures or patterns to the outer surface of the light-shielding laminate 10 . The thickness of the design printed layer 14 can be, for example, 0.1 μm or more and 10 μm or less. The design printed layer 14 may be composed of a single layer, or may be composed of multiple layers.

<Light shielding layer>
The purpose of the light shielding layer 12 is to prevent the light from reaching the inside of the container in which the light shielding laminate 10 is mounted by reflecting the light transmitted through the shielding layer 13 from the outside of the light shielding laminate 10. It is a layer made of printing ink. The thickness of the light shielding layer 12 can be, for example, 0.05 μm or more and 10 μm or less. In this specification, "from the outside of the light-shielding laminate 10" means the outside of the light-shielding laminate 10 on the side where the shielding layer 13 on the surface 11a of the substrate 11 is formed.

The light shielding layer 12 is a layer containing aluminum and titanium oxide. As aluminum, for example, spherical aluminum particles, scale-like (flake-like) aluminum flakes, or thin film-like aluminum flakes can be used. As titanium oxide, for example, rutile-type titanium oxide having an average particle size of about 0.27 μm can be used. Moreover, the light shielding layer 12 may further contain carbon black.

The light shielding layer 12 may further contain a binder resin. The binder resin contained in the light shielding layer 12 includes, for example, acrylic resin, urethane resin, acrylic-urethane resin, vinyl chloride vinyl acetate copolymer, cellulose resin (nitrocellulose resin, cellulose acetate butyrate resin, cellulose acetate propionate resin). etc.) or a mixed resin thereof can be used. As the binder resin contained in the layers forming the light shielding layer 12, for example, a binder resin made of urethane resin and cellulose resin can be used.

<Surface protective layer>
The surface protective layer 17 is a layer for protecting the shielding layer 13 or the design printed layer 14 from external damage or the like. As the surface protective layer 17, a layer made of overprint varnish, for example, can be used. The surface protective layer 17 may be colorless and transparent, colored and transparent, glossy, matte, or a multilayer thereof.

<Slippery layer>
The slipperiness imparting layer 16 is intended to improve the slipperiness of the light-shielding laminate 10 on the outer surface of the container to which the light-shielding laminate 10 is attached when the light-shielding laminate 10 is attached to the outer surface of the container. It is a layer provided for the purpose. When the slipperiness imparting layer 16 is provided on the back surface 11b of the substrate 11, the slipperiness imparting layer 16 is positioned on the opposite side of the substrate 11 to the side where the shielding layer 13 is positioned.

For example, a white ink layer containing a white pigment and a binder resin can be used as the slipperiness imparting layer 16 . As the white pigment for the white ink layer that constitutes the slipperiness imparting layer 16, for example, the same white pigment as that for the white ink layer that constitutes the shielding layer 13 can be used. As the binder resin for the white ink layer forming the slipperiness imparting layer 16, for example, the same binder resin as that for the white ink layer forming the shielding layer 13 can be used.

The content of the white pigment in the white ink layer forming the slipperiness imparting layer 16 can be, for example, 80% by weight or less of the white ink layer forming the slipperiness imparting layer 16 . In order to give the lubricity imparting layer 16 a shielding function, the content of the white pigment in the white ink layer constituting the lubricity imparting layer 16 is, for example, 60% of the white ink layer constituting the lubricity imparting layer 16. % by weight or more. As the lubricity-imparting layer 16, in addition to a white ink layer containing a white pigment and a binder resin, for example, a pigment-free layer such as an inner surface varnish (medium) can also be used.

<Underlayer>
FIG. 2 shows a schematic cross-sectional view of another example of the light-shielding laminate 10 according to Embodiment 1. As shown in FIG. The light-shielding laminate 10 according to Embodiment 1 shown in FIG. 2 is characterized by further including an alkali-soluble base layer 15 between the substrate 11 and the light-shielding layer 12 . The base layer 15 is formed by removing the light-shielding layer 12 and the shielding layer from the light-shielding layered body 10 by, for example, recovering the light-shielding layered body 10 from a used container and immersing the light-shielding layered body 10 in an alkaline solution. 13 and the like can be removed, and the base material 11 can be separated and recovered from the light-shielding laminate 10 according to Embodiment 1 for recycling or the like. In addition, in the light-shielding laminate 10 according to Embodiment 1, since the layers such as the light-shielding layer 12 and the light-shielding layer 13 are positioned on the same side of the substrate 11, there is a gap between the substrate 11 and the light-shielding layer 12. There is an advantage that it is sufficient to provide the alkali-soluble underlayer 15 only at one location.

Further, without using the base layer 15, for example, the light-shielding layer 12 and the shielding layer 13 on the base material 11 are removed only by physical force on the light-shielding laminate 10 according to Embodiment 1, and the base material 11 is removed. When separating and recovering, the layers such as the light shielding layer 12 and the shielding layer 13 are positioned on the same side of the substrate 11, so that the substrate 11 can be separated and recovered from the light shielding laminate 10 according to Embodiment 1. It also has the advantage of facilitating

Examples of the alkali-soluble base layer 15 include a base layer 15 containing an alkali-soluble resin. As the alkali-soluble resin, for example, resins having the following (1) to (4) can be used.
(1) contains a first resin that is an acrylic acid copolymer resin having a first glass transition temperature T1;
(2) contains a second resin that is an acrylic acid copolymer resin having a second glass transition temperature T2 lower than T1;
(3) the apparent acid value of the underlayer 15 is 40 mgKOH/g or more and 150 mgKOH/g or less;
(4) The total amount of the first resin and the second resin contained in the base layer 15 accounts for 50 to 95% by mass of the base layer 15 as a whole.

A resin having the above (1) to (4) has good alkali solubility. Therefore, by providing the base layer 15 containing an alkali-soluble resin between the substrate 11 and the light-shielding layer 12, the light-shielding laminate 10 according to the first embodiment can As the base layer 15 is desorbed with alkali, the layer on the base material 11 is also desorbed from the light-shielding laminate 10 according to the first embodiment.

As shown in (1) and (2) above, the first resin and the second resin are acrylic acid copolymer resins, respectively. An acrylic acid copolymer resin is a resin containing acrylic acid and/or methacrylic acid as a main repeating unit and a copolymerizable monomer copolymerizable with acrylic acid and/or methacrylic acid. The acrylic acid copolymer resin preferably has a total proportion of acrylic acid and/or methacrylic acid and copolymer monomers in the resin of 60 mol % or more.

Regarding (1) and (2) above, T1, which is the Tg of the first resin, is preferably 90°C or higher, and particularly preferably 100°C or higher. The upper limit of T1 can be, for example, about 120° C. from the physical properties of the acrylic acid copolymer resin. T2, which is the Tg of the second resin, is preferably less than 80°C, particularly preferably 65°C or less. The lower limit of T2 can be, for example, about 30° C. from the viewpoint of ease of handling. T1 and T2 preferably have a difference of, for example, 20° C. or more, and particularly preferably have a difference of 40° C. or more. This is because in this case, the printability of the base layer 15 can be improved.

Regarding (3) above, the apparent acid value of the underlayer 15 means the acid value of the mixed resin composed of two or more resins contained in the underlayer 15 . The apparent acid value of the underlayer 15 can be adjusted by controlling the acid values of the first resin and the second resin.

Regarding (3) above, the apparent acid value of the underlayer 15 is more preferably 50 mgKOH/g or more and 130 mgKOH/g or less, and particularly preferably 55 gKOH/g or more and 125 mgKOH/g or less. In these cases, it is possible to particularly improve the alkali solubility and printability of the underlayer 15 .

Regarding (4) above, it is preferable that the total amount of the first resin and the second resin in the base layer 15 accounts for 70% by mass or more and 95% by mass or less of the entire base layer 15 . In these cases, it is possible to particularly improve the alkali solubility and printability of the underlayer 15 . From the viewpoint of improving the synergistic effect by containing two types of resins, the first resin and the second resin, the ratio of the content of the first resin to the content of the second resin (relatively large content The ratio of resin content/relatively small resin content) is preferably 3 or less.

For example, various analysis techniques can be used to confirm that the underlayer 15 contains an alkali-soluble resin. For example, by nuclear magnetic resonance (NMR), gas chromatography mass spectrometry (GCMS), pyrolysis gas chromatography (pyrolysis GCMS), or the like, the acrylic acid copolymer resin exists in the underlayer 15 at a specific content. can be confirmed. Also, the acid value of the underlying layer 15 can be confirmed by, for example, titrating the underlying layer 15 . Also, the Mm of the first resin and the Mm of the second resin can be confirmed by gel permeation chromatography (GPC), for example.

The above-mentioned first resin and second resin are preferably methacrylic acid-methyl methacrylic acid copolymer (hereinafter also referred to as "MM copolymer"). In this case, it is possible to remarkably improve both the alkali solubility and printability of the underlayer 15 .

The base layer 15 may contain other components in addition to the first resin and the second resin. Other preferred ingredients include cellulose derivatives. When the underlayer 15 contains a cellulose derivative, it is possible to improve the blocking resistance, adhesion, etc. of the underlayer 15 .

The content of the cellulose derivative in the underlying layer 15 is preferably 1% by mass or more and 20% by mass or less of the total mass of the underlying layer 15 . In this case, the blocking resistance and printability of the underlying layer 15 can be improved.

In addition, the underlayer 15 may contain, for example, a vinyl chloride-vinyl acetate copolymer (hereinafter also referred to as "VV copolymer") as another preferred component. Including the VV copolymer in the underlayer 15 makes it possible to further improve the adhesion between the substrate 101 and the underlayer 15 .

The content of the VV copolymer in the underlayer 15 is preferably 5 to 20% by mass, particularly preferably 9 to 12% by mass, of the total mass of the underlayer 15. In these cases, the adhesion and printability of the underlying layer 15 can be improved.

<Method for producing light-shielding laminate>
The light-shielding laminate 10 according to Embodiment 1 can be manufactured, for example, as follows. First, a step of preparing the base material 11 is performed. The substrate 11 is formed by, for example, extruding (T-die method, inflation method, tubular method, etc.) or calendering method to form a film, and if necessary, the film is further stretched. can be prepared by applying

Next, a step of forming the light shielding layer 12 on the surface 11a of the base material 11 is performed. The step of forming the light shielding layer 12 can be carried out, for example, by printing the ink for forming the light shielding layer 12 on the substrate 11 and then drying it.

As the ink for forming the light shielding layer 12, for example, a resin composition containing a binder resin, aluminum, titanium oxide, and a solvent can be used.

Further, when the alkali-soluble base layer 15 is provided between the base material 11 and the light shielding layer 12, the step of forming the light shielding layer 12 on the surface 11a of the base material 11 is performed on the surface 11a of the base material 11. A step of forming the underlying layer 15 and a step of forming the light shielding layer 12 on the underlying layer 15 may be included.

The step of forming the base layer 15 on the surface 11a of the base material 11 can be carried out, for example, by printing alkali-soluble ink for forming the base layer 15 on the surface 11a of the base material 11 and then drying it.

The step of forming the light shielding layer 12 on the base layer 15 can be performed, for example, by printing the ink for forming the light shielding layer 12 on the base layer 15 and then drying it.

Next, a step of forming the shielding layer 13 on the shielding layer 12 is performed. The step of forming the shielding layer 13 can be performed, for example, by printing ink for forming the shielding layer 13 on the shielding layer 12 and then drying the ink.

As the ink for forming the shielding layer 13, for example, a resin composition containing a binder resin, a white pigment, and a solvent can be used.

After that, the step of forming the design layer 14 on the shielding layer 13 is performed. The step of forming the design layer 14 can be carried out, for example, by printing the ink for forming the design layer 14 on the shielding layer 13 and then drying it.

When the light-shielding laminate 10 according to Embodiment 1 further includes other layers such as the surface protective layer 17 and/or the slipperiness imparting layer 16, for example, after printing the ink for forming these layers, These other layers can be formed by drying or the like. Through the steps described above, the light-shielding laminate 10 according to the first embodiment can be manufactured.

<Effect>
Since the light-shielding layer 12 of the light-shielding laminate 10 according to Embodiment 1 contains aluminum and titanium oxide, compared to a conventional light-shielding laminate in which the light-shielding layer 12 contains only aluminum as a light-shielding substance, The light shielding property of the light shielding laminate 10 from the outside can be improved. In addition, since the light-shielding layer 12 of the light-shielding laminate 10 according to Embodiment 1 contains aluminum and titanium oxide, the light-shielding layer 12 contains only aluminum as a light-shielding substance. As a result, the color of the light shielding layer 12 becomes bright, and the color of the light shielding layer 13 thereon also appears bright, so that the appearance of the light shielding laminate 10 can be made beautiful. According to Embodiment 1, due to the effect of the combination of the light shielding layer 12 and the shielding layer 13, it is possible to exhibit a high degree of whiteness (high L* value) while providing sufficient light shielding properties, so design printing is performed from the surface side. When the layer 14 is visually recognized, a beautiful color can be exhibited as a whole.

Compared to a conventional light-shielding laminate in which the light-shielding layer 12 contains only aluminum as a light-shielding substance, the light-shielding property of the light-shielding laminate 10 from the outside is further improved, and the appearance of the light-shielding laminate 10 is improved. From the viewpoint of making the light shielding layer 12 beautiful, the weight of aluminum is preferably 7% or more and 41% or less, and more preferably 7% or more and 23% or less, when the total weight of the light shielding layer 12 is 100%. It is more preferably 7% or more and 20% or less, and particularly preferably 7% or more and 13% or less.

Compared to a conventional light-shielding laminate in which the light-shielding layer 12 contains only aluminum as a light-shielding substance, the light-shielding property of the light-shielding laminate 10 from the outside is further improved, and the appearance of the light-shielding laminate 10 is improved. From the viewpoint of making it look beautiful, the volume occupied by aluminum is preferably 6% or more and 28% or less, and more preferably 6% or more and 17% or less, when the total volume of the light shielding layer 12 is 100%. It is more preferably 6% or more and 15% or less, and particularly preferably 6% or more and 11% or less.

Compared to a conventional light-shielding laminate in which the light-shielding layer 12 contains only aluminum as a light-shielding substance, the light-shielding property of the light-shielding laminate 10 from the outside is further improved, and the appearance of the light-shielding laminate 10 is improved. From the viewpoint of making the light-shielding layer 12 look beautiful, the weight of titanium oxide is preferably 24% or more and 68% or less, and more preferably 48% or more and 68% or less when the total weight of the light shielding layer 12 is 100%. is more preferably 52% or more and 68% or less, and particularly preferably 61% or more and 68% or less.

Compared to a conventional light-shielding laminate in which the light-shielding layer 12 contains only aluminum as a light-shielding substance, the light-shielding property of the light-shielding laminate 10 from the outside is further improved, and the appearance of the light-shielding laminate 10 is improved. From the viewpoint of making it beautiful, the volume occupied by titanium oxide is preferably 10% or more and 38% or less, and 23% or more and 38% or less, when the total volume of the light shielding layer 12 is 100%. is more preferably 26% or more and 38% or less, and particularly preferably 32% or more and 38% or less.

Compared to a conventional light-shielding laminate in which the light-shielding layer 12 contains only aluminum as a light-shielding substance, the light-shielding property of the light-shielding laminate 10 from the outside is further improved, and the appearance of the light-shielding laminate 10 is improved. From the viewpoint of making it beautiful, the ratio of the weight of titanium oxide to the weight of aluminum in the light shielding layer 12 ((weight of titanium oxide)/(weight of aluminum)) should be 0.59 or more and 9.71 or less. is preferably 2.09 or more and 9.71 or less, more preferably 2.6 or more and 9.71 or less, and particularly preferably 4.69 or more and 9.71 or less.

Compared to a conventional light-shielding laminate in which the light-shielding layer 12 contains only aluminum as a light-shielding substance, the light-shielding property of the light-shielding laminate 10 from the outside is further improved, and the appearance of the light-shielding laminate 10 is improved. From the viewpoint of making it beautiful, the ratio of the volume of titanium oxide to the volume of aluminum in the light shielding layer 12 ((volume of titanium oxide)/(volume of aluminum)) should be 0.36 or more and 6.3 or less. is preferably 1.35 or more and 6.3 or less, more preferably 1.73 or more and 6.3 or less, and particularly preferably 2.91 or more and 6.3 or less.
As another example of the configuration of the light-shielding laminate 10 according to Embodiment 1, the shielding layer 13 is laminated on the back side of the base material 11, and the shielding layer 13 and the design printed layer are laminated on the front side of the base material 11. 14 may be laminated in this order, and an inner surface protective layer (for example, white or transparent) may be laminated on the outermost layer on the back side. The inner surface protective layer may have slipperiness. As still another example, a shielding layer 13 and a light shielding layer 12 are laminated in this order from the substrate 11 side on the back surface side of the substrate 11, and a design printing including a white base layer is provided on the surface side of the substrate 1. The layer 14 may be laminated, and an inner surface protective layer (for example, white or transparent) may be laminated on the outermost layer on the back side. When the design printing layer 14 has a white base layer, it can be more beautiful. Here, the white base layer is a layer of the design layer 14 that is arranged closest to the substrate 11 side, is often solidly coated, and can also have shielding properties.

The light-shielding laminate 10 according to Embodiment 1 has the following advantages over the light-shielding laminate described in Patent Document 1.

When the light-shielding laminate described in Patent Document 1 is attached to a container, for example, as shown in the schematic side view of FIG. and the second end vicinity region 10b, which is the other end vicinity region, are positioned so as to overlap each other, and the base material 11 of the first end vicinity region 10a and The light-shielding laminate described in Patent Document 1 is formed in a cylindrical shape by joining the base material 11 in the second end vicinity region 10b at the sealing portion 10c by, for example, thermal bonding, solvent bonding, or the like.

However, in the light-shielding laminate described in Patent Document 1, for example, as shown in the schematic cross-sectional view of FIG. From the gap (region S1) between the shielding layer 13 and the first end vicinity region 10a, the silvery color of the light shielding layer 12 is visible in a linear shape along the axial direction. This impairs the beauty of the appearance of the laminate. In particular, since the light-shielding layer 12 of the light-shielding laminate described in Patent Document 1 contains only aluminum as the light-shielding substance, this tendency is remarkable. In addition, when such a cylindrical light-shielding laminate is thermally shrunk, the base material 11 in the second end vicinity region 10b is less regulated by the container, so it shrinks more than the other portions. . With this large shrinkage, the light-shielding layer 12 and the slipperiness imparting layer 16 in the first end vicinity region 10a contacting the second end vicinity region 10b contract in the contraction direction of the base material 11 in the second end vicinity region 10b. As a result, cracks may occur in the silver ink layer forming the light shielding layer 12 in the first end vicinity region 10a.

Further, for example, as shown in the schematic cross-sectional view of FIG. 5, the shielding layer 13 in the first end vicinity region 10a and the shielding layer in the second end vicinity region 10b of the light-shielding laminate described in Patent Document 1 13 (region S1), the light shielding layer 12 is positioned so as not to protrude from the shielding layer 13 in the second end vicinity region 10b. In this case, since the shielding layer 12 does not exist in the region S2, which is wider than the region S1, the light shielding property of the light shielding laminate described in Patent Document 1 from the outside is deteriorated.

On the other hand, when the light-shielding laminate 10 according to Embodiment 1 is formed in a cylindrical shape like the light-shielding laminate described in Patent Document 1, for example, as shown in the schematic cross-sectional view of FIG. Since the light shielding layer 12 can be positioned so as not to protrude from the shielding layer 13 in the end vicinity region 10b, the shielding layer 13 in the first end vicinity region 10a and the shielding layer 13 in the second end vicinity region 10b 13 (region S1), the silver color of the light shielding layer 12 in the first end vicinity region 10a cannot be seen. Therefore, the appearance of the light-shielding laminate 10 according to Embodiment 1 tends not to be impaired as compared with the light-shielding laminate described in Patent Document 1.

When the light-shielding laminate 10 according to Embodiment 1 is attached to a container, the light-shielding layer 12 is preferably provided in 50% or more of the area of the light-shielding laminate 10, and is provided in 80% or more. More preferably, it is provided in 90% or more. In this case, the contents of the container can be suitably protected from external light by the light shielding layer 12 . Moreover, when the light-shielding laminate 10 is attached to a container, the shielding layer 13 preferably covers the entire light-shielding layer 12 . In this case, the appearance of the light-shielding laminate 10 according to Embodiment 1 can be made more beautiful.

The light-shielding laminate 10 according to Embodiment 1 can be used, for example, with water, juice, green tea, black tea, oolong tea, coffee, barley tea, matcha green tea, pu-erh tea, Japanese sake, mirin, ponzu sauce, vinegar, oil, vitamin-containing beverages, and specific beverages. Health drinks, nutritional supplements, milk, dairy drinks, lactic acid bacteria drinks, yogurt, beer, whiskey, brandy, rum, red wine, white wine, rosé wine, cocktails, soy sauce, sauces, dipping sauces, sauces, dashi, dressings , mayonnaise, lotion, milky lotion, toner, shampoo, rinse, liquid medicine, or liquid chemical. In particular, it can be suitably used for products that have contents that need to be shielded from light in order to maintain taste, function, etc., and that require appeal to consumers and the like.

In particular, by attaching the light-shielding laminate 10 according to Embodiment 1 to the entire container such as a plastic bottle or a glass bottle, it has excellent light-shielding properties in the visible light region and the ultraviolet light region, and also has a good appearance. We can provide excellent containers.

[Embodiment 2]
FIG. 7A shows a schematic cross-sectional view of an example of the light-shielding laminate 10 according to Embodiment 2. As shown in FIG. The light-shielding laminate 10 according to Embodiment 2 does not have the light-shielding layer 12 on the surface 11a of the base material 11, but the base material 11 on the side opposite to the side where the shielding layer 13 of the base material 11 is located. A light shielding layer 12 is provided on the rear surface 11b of the.

That is, an example of the light-shielding laminate 10 according to Embodiment 2 includes, as shown in FIG. and a light-shielding layer 12 on the back surface 11 b of the base material 11 and a slipping layer 16 on the light-shielding layer 12 .
The light shielding layer 12 of the light shielding laminate 10 according to Embodiment 2 also contains aluminum and titanium oxide. Therefore, in the light-shielding laminate 10 according to Embodiment 2 as well, compared to a conventional light-shielding laminate in which the light-shielding layer 12 contains only aluminum as a light-shielding substance (for example, the light-shielding laminate described in Patent Document 1), The light shielding property of the light shielding laminate 10 from the outside can be improved. In addition, since the light-shielding layer 12 of the light-shielding laminate 10 according to the second embodiment contains aluminum and titanium oxide, the color of the light-shielding layer 13 becomes bright, and the light-shielding layer 12 contains only aluminum as a light-shielding substance. The appearance of the light-shielding laminate 10 can be made beautiful as compared with a conventional light-shielding laminate (for example, the light-shielding laminate described in Patent Document 1) containing.

FIG. 7B shows a schematic cross-sectional view of a modification of the light-shielding laminate according to Embodiment 2. As shown in FIG. The light-shielding laminate 10 according to this modification is characterized by having a shielding layer 13 on the back surface 11b of the substrate 11 in addition to the shielding layer 13 on the surface 11a of the substrate 11. The configuration is similar.
Here, the shielding layer 13 on the front side is provided by printing and drying, for example, NT Hiramic (NF) 701 White (manufactured by Dainichiseika Co., Ltd.). The shielding layer 13 on the front side preferably has a white pigment content of 60 to 95% by weight, more preferably 75 to 90% by weight, based on the entire layer. The shielding layer 13 on the front side may contain solid wax, but when color printing is repeated, the shielding layer on the front side preferably does not contain solid wax from the viewpoint of design.
On the other hand, the shielding layer 13 on the back side is provided by printing and drying, for example, NT Hiramic (NF) 701 White (manufactured by Dainichiseika Co., Ltd.). The back shielding layer 13 preferably has a white pigment content of 60 to 95% by weight, more preferably 75 to 90% by weight, based on the entire layer.

FIG. 8A shows a schematic cross-sectional view of another example of the light-shielding laminate 10 according to Embodiment 2. FIG. Another example of the light-shielding laminate 10 according to Embodiment 2 shown in FIG. It is characterized by having

Also in the light-shielding laminate 10 according to Embodiment 2 shown in FIG. The light shielding layer 12 and the shielding layer 13 on the substrate 11 can be removed from 10, and the substrate 11 can be separated and recovered from the light shielding laminate 10 according to Embodiment 2 for recycling or the like.

The light-shielding laminate 10 according to Embodiment 2 can be manufactured, for example, as follows.

First, the step of preparing the base material 11 is performed, and then the step of forming the shielding layer 13 on the surface 11a of the base material 11 is performed. When the base layer 15 is provided between the base material 11 and the shielding layer 13, the step of forming the shielding layer 13 on the surface 11a of the base material 11 includes forming the base layer 15 on the surface 11a of the base material 11. and forming the shielding layer 13 on the underlying layer 15 .

Further, a step of forming the light shielding layer 12 on the rear surface 11b of the base material 11 is performed. When the base layer 15 is provided between the base material 11 and the light shielding layer 12, the step of forming the light shielding layer 12 on the back surface 11b of the base material 11 includes forming the base layer 15 on the back surface 11b of the base material 11. and a step of forming the light shielding layer 12 on the underlying layer 15 .
After that, a step of forming a design layer 14 on the shielding layer 13 is performed. Further, when the light-shielding laminate 10 according to Embodiment 2 further includes other layers such as the surface protective layer 17 and/or the slipperiness imparting layer 16, for example, ink for forming these layers is printed. These other layers can be formed, such as by drying after coating. Through the steps described above, the light-shielding laminate 10 according to Embodiment 2 can be manufactured.

FIG. 8B shows a schematic cross-sectional view of another modification of the light-shielding laminate according to Embodiment 2. As shown in FIG. The light-shielding laminate 10 according to this modification includes the shielding layer 13 on the surface 11a of the base material 11 with the base layer 15 interposed therebetween. A shielding layer 13 is also provided on the back surface 11b with an underlying layer 15 interposed therebetween, and other configurations are the same.
Here, the shielding layer 13 on the front side is provided by printing and drying, for example, NT Hiramic (NF) 701 White (manufactured by Dainichiseika Co., Ltd.). The shielding layer 13 on the front side preferably has a white pigment content of 60 to 95% by weight, more preferably 75 to 90% by weight, based on the entire layer. The shielding layer 13 on the front side may contain solid wax, but when color printing is repeated, the shielding layer on the front side preferably does not contain solid wax from the viewpoint of design.
On the other hand, the shielding layer 13 on the back side is provided by printing and drying, for example, NT Hiramic (NF) 701 White (manufactured by Dainichiseika Co., Ltd.). The back shielding layer 13 preferably has a white pigment content of 60 to 95% by weight, more preferably 75 to 90% by weight, based on the entire layer.

Since the description of the second embodiment other than the above is the same as that of the first embodiment, the description will not be repeated.
If two shielding layers 13 are provided on the front and back sides of the base material 11 as in the two modifications of the second embodiment, the brightness from the front side of the label can be increased, and the properties of the milky white label can be improved. In addition, it is possible to prevent the light-shielding laminate 10 from curling to one side during heat shrinkage or label storage. This is because printing is balanced by providing two shielding layers 13 on the front and back sides of the substrate 11, so that curling in one direction is prevented.
Furthermore, the two shielding layers 13 provided on the front and back sides of the substrate 11 may have the same or different concentrations of white pigment. When the density of the white pigment of the shielding layer 13 is the same on the front and back sides, the density may be low or high. The modified example of Embodiment 2 has two shielding layers 24 on both sides of the base material, so that it is possible to suppress poor ink drying. By setting the density of the white pigment in both the shielding layers 13 provided on the front and back surfaces to be high, the light shielding laminate 10 with relatively high brightness can be obtained. If the front and back have different white densities, the visual impression can be changed even if the degree of shielding is the same. For example, when the surface white is low density and the back surface white is high density, the printability of the design layer to be overlaid thereon is improved, and a light-shielding laminate with excellent design can be obtained. In addition, when the surface white is high-concrete and the back-surface white is low-concrete, the brightness of the surface can be increased and the anti-curling property can be further improved. Here, high-concentration refers to a white pigment content of 75 to 95% by weight with respect to the entire layer of the shielding layer 13, and low-concentration refers to a white pigment content of 60% to 75% by weight with respect to the entire layer. means less than

<Production of light-shielding laminates of Experimental Examples 1 to 11>
Light-shielding laminates 10 of Experimental Examples 2 to 10 having the cross section shown in FIG. 9 were produced. First, as the ink for forming the light-shielding layer, a silver ink (trade name: NT Hiramic (trade name: NT Hiramic ( NF) 120 silver) and a predetermined amount of titanium oxide (trade name: JR707, average particle size: 0.27 μm, crystal form: rutile type, specific gravity: 4.2). ) 701 White) and then diluted with a solvent as appropriate to prepare samples in which the blending amounts of aluminum flakes and titanium oxide were changed in each of Experimental Examples 2 to 10.

Next, a PET film, which is a shrink film with a thickness of 30 μm, was prepared as the base material 11 . Next, the light shielding layer 12 was formed by printing the light shielding layer forming ink on the surface 11a of the base material 11 and drying it.

Next, a shielding layer 13 was formed by performing a step of printing and drying shielding layer forming ink (white ink (trade name: NT Hiramic (NF) 701 white)) on the shielding layer 12 . As described above, light-shielding laminates 10 of Experimental Examples 2 to 10 were produced.

Further, the light-shielding properties of Experimental Example 1 were obtained in the same manner as in Experimental Examples 2 to 10, except that only silver ink (trade name: NT Hiramic (NF) 120 silver) was used as the ink for forming the light-shielding layer 12. A laminate 10 was produced. Further, a light-shielding laminate 10 of Experimental Example 11 was produced in the same manner as in Experimental Examples 2 to 10, except that only white ink was used as the light-shielding layer forming ink for forming the light-shielding layer 12 .

The light-shielding laminates 10 of Experimental Examples 1 to 11 were prepared so that the weight ratio [%] of the constituent components of the light-shielding layer 12 was the value shown in the columns of Experimental Examples 1 to 11 in Table 1 below, and the light-shielding The layer 12 was manufactured so that the volume ratios [%] of the constituent components of the layer 12 were the values shown in the columns of Experimental Examples 1 to 11 in Table 2 below. Experimental Examples 2 to 10 are examples, and Experimental Examples 1 and 11 are comparative examples.

The numerical values in the column of aluminum flakes, the column of titanium oxide, and the column of binder resin in Table 1 each mean the weight ratio [%] of each component when the total weight of the light shielding layer 12 is 100 [%]. are doing.
Further, the numerical values in the column of weight of titanium oxide/weight of aluminum flakes in Table 1 are the ratio of the weight of titanium oxide to the weight of aluminum in the light shielding layer 12 ((weight of titanium oxide)/(weight of aluminum flakes)). means

In addition, the numerical values in the column of aluminum flakes, the column of titanium oxide, and the column of binder resin in Table 2 mean the volume ratio [%] of each component when the total volume of the light shielding layer 12 is 100 [%]. are doing. Further, the numerical values in the column of volume of titanium oxide/volume of aluminum flakes in Table 2 are the ratio of the volume of titanium oxide to the volume of aluminum in the light shielding layer 12 ((volume of titanium oxide)/(volume of aluminum flakes)). means

<Method for evaluating light shielding properties of light shielding laminates of Experimental Examples 1 to 11>
The total light transmittance [%] for light with a wavelength of 250 nm or more and 800 nm or less was measured for each of the light-shielding laminates of Experimental Examples 1 to 11 produced as described above. The results are shown in FIG. The horizontal axis of FIG. 10 indicates the wavelength of light [nm], and the vertical axis of FIG. 10 indicates the total light transmittance [%]. For the total light transmittance, light was incident from the shielding layer 13 side of the light-shielding laminates 10 of Experimental Examples 1 to 11, and the amount of light passing through the substrate 11 was measured based on JIS K 7375:2008. The smaller the value of the total light transmittance [%] shown in FIG. 10, the better the light shielding properties.

<Method for evaluating aesthetic appearance of light-shielding laminates of Experimental Examples 1 to 11>
The L* value of the L*a*b* color system was calculated based on JIS Z 8781-4 for the shielding layer 13 of each of the light-shielding laminates of Experimental Examples 1 to 11 produced as described above. I asked. Table 3 shows the results.

The larger the L* value in Table 3, the brighter the color of the shielding layer 13 of the light-shielding laminate, and the higher the appearance of the light-shielding laminate.

<Evaluation results of the light-shielding laminates of Experimental Examples 1 to 11>
As shown in FIG. 10, the light-shielding laminates of Experimental Examples 2 to 10 had a lower total light transmittance for light with a wavelength of about 380 nm to 780 nm than the light-shielding laminate of Experimental Example 11. Therefore, from this result, it can be seen that the light-shielding laminates of Experimental Examples 2 to 10 have a light-shielding property against light with a wavelength of about 380 nm to 780 nm. was confirmed to be superior to Further, as shown in FIG. 10, although the light shielding property of the white ink layer alone is low (Experimental Example 11), the light shielding property can be greatly improved by adding a small amount of aluminum flakes to the white ink layer. (Experimental Examples 9-10) was also confirmed.

Also, as shown in Table 3, the L* values of the light-shielding laminates of Experimental Examples 2 to 10 were larger than the L* values of the light-shielding laminate of Experimental Example 1. Therefore, from this result, the light-shielding laminates of Experimental Examples 2 to 10 containing aluminum flakes and titanium oxide were compared with the light-shielding laminate of Experimental Example 1 containing only aluminum flakes as the light-shielding substance of the light-shielding layer 12. It has been confirmed that the appearance is more beautiful than the other.

Further, as shown in Table 3, the L* values of the light-shielding laminates of Experimental Examples 5 to 10 are larger than the L* values of the light-shielding laminates of Experimental Examples 2-4, and the light-shielding properties of Experimental Examples 7-10. The L* value of the laminate is greater than the L* value of the light-shielding laminates of Experimental Examples 5 and 6, and the L* value of the light-shielding laminates of Experimental Examples 9-10 is the same as that of the light-shielding laminates of Experimental Examples 7-8. was larger than the L* value of Therefore, from this result, the light-shielding laminates of Experimental Examples 5-10 have higher appearance than the light-shielding laminates of Experimental Examples 2-4, and the light-shielding laminates of Experimental Examples 5-6. Compared to the light-shielding laminates of Experimental Examples 7-10, the appearance is higher, and the light-shielding laminates of Experimental Examples 9-10 are more beautiful than the light-shielding laminates of Experimental Examples 7-8. It was confirmed that the beauty was high.

In addition, from the comparison of the evaluation results of the light shielding properties and appearance of the light shielding laminates of Experimental Examples 1 to 11 shown in FIG. 10 and Table 3, the light shielding ability of the light shielding laminate 10 from outside was further improved In addition, from the viewpoint of making the appearance of the light-shielding laminate 10 more beautiful, the weight of aluminum should be 7% or more and 41% or less when the total weight of the light-shielding layer 12 is 100%. It was confirmed that the content is preferably 7% or more and 23% or less, more preferably 7% or more and 20% or less, and particularly preferably 7% or more and 13% or less.

In addition, from the comparison of the evaluation results of the light shielding properties and appearance of the light shielding laminates of Experimental Examples 1 to 11 shown in FIG. 10 and Table 3, the light shielding ability of the light shielding laminate 10 from outside was further improved In addition, from the viewpoint of making the appearance of the light-shielding laminate 10 more beautiful, the volume occupied by aluminum is preferably 6% or more and 28% or less when the total volume of the light-shielding layer 12 is taken as 100%. It was confirmed that the content is preferably 6% or more and 17% or less, more preferably 6% or more and 15% or less, and particularly preferably 6% or more and 11% or less.

In addition, from the comparison of the evaluation results of the light shielding properties and appearance of the light shielding laminates of Experimental Examples 1 to 11 shown in FIG. 10 and Table 3, the light shielding ability of the light shielding laminate 10 from outside was further improved In addition, from the viewpoint of making the appearance of the light-shielding laminate 10 more beautiful, the weight of titanium oxide should be 24% or more and 68% or less when the total weight of the light-shielding layer 12 is 100%. is preferred, 48% or more and 68% or less is more preferred, 52% or more and 68% or less is even more preferred, and 61% or more and 68% or less is particularly preferred.

In addition, from the comparison of the evaluation results of the light shielding properties and appearance of the light shielding laminates of Experimental Examples 1 to 11 shown in FIG. 10 and Table 3, the light shielding ability of the light shielding laminate 10 from outside was further improved In addition, from the viewpoint of making the appearance of the light-shielding laminate 10 more beautiful, the volume occupied by titanium oxide should be 10% or more and 38% or less when the total volume of the light-shielding layer 12 is 100%. is preferred, 23% or more and 38% or less is more preferred, 26% or more and 38% or less is even more preferred, and 32% or more and 68% or less is particularly preferred.

In addition, from the comparison of the evaluation results of the light shielding properties and appearance of the light shielding laminates of Experimental Examples 1 to 11 shown in FIG. 10 and Table 3, the light shielding ability of the light shielding laminate 10 from outside was further improved In addition, from the viewpoint of making the appearance of the light-shielding laminate 10 more beautiful, the ratio of the weight of titanium oxide to the weight of aluminum in the light-shielding layer 12 ((weight of titanium oxide)/(weight of aluminum)) is , preferably from 0.59 to 9.71, more preferably from 2.09 to 9.71, even more preferably from 2.6 to 9.71, and from 4.69 to 9 It was confirmed that it is particularly preferable to be 0.71 or less.

In addition, from the comparison of the evaluation results of the light shielding properties and appearance of the light shielding laminates of Experimental Examples 1 to 11 shown in FIG. 10 and Table 3, the light shielding ability of the light shielding laminate 10 from outside was further improved In addition, from the viewpoint of making the appearance of the light-shielding laminate 10 more beautiful, the ratio of the volume of titanium oxide to the volume of aluminum in the light-shielding layer 12 ((volume of titanium oxide)/(volume of aluminum)) is , preferably from 0.36 to 6.3, more preferably from 1.35 to 6.3, even more preferably from 1.73 to 6.3, and from 2.91 to 6 It was confirmed that it is particularly preferable to be 0.3 or less.

The L* value of the light-shielding laminates 10 of Experimental Examples 2 to 10 having the cross section shown in FIG. 10 is preferably 80 or more, more preferably 82 or more, from the viewpoint of improving beauty. It is preferably 85 or more, and more preferably 85 or more.

Although the embodiments and experimental examples have been described as above, it is planned from the beginning to appropriately combine the configurations of the above-described embodiments and experimental examples.

The embodiments and experimental examples disclosed this time should be considered illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning of equivalents of the scope of the claims.

10 Light-shielding laminate 10a First end vicinity region 10b Second end vicinity region 10c Seal portion 11 Base material 11a Front surface 11b Back surface 12 Light shielding layer 13 Shielding layer 14 Design layer 15 base layer, 16 slipping layer, 17 surface protective layer.

Claims (6)

1. a substrate;
   a shielding layer on the substrate;
   a light shielding layer located between the substrate and the shielding layer or on the opposite side of the substrate from the shielding layer;
   A light-shielding laminate, wherein the light-shielding layer contains aluminum and titanium oxide.
2. When the total weight of the light shielding layer is 100%, the weight of the aluminum is 7% or more and 41% or less, and the weight of the titanium oxide is 24% when the total weight of the light shielding layer is 100%. 68% or more, or the ratio of the weight of the titanium oxide to the weight of the aluminum in the light shielding layer ((weight of the titanium oxide)/(weight of the aluminum)) is 0.59 or more and 9.71 or less The light-shielding laminate according to claim 1, comprising:
3. The light-shielding laminate according to claim 1 or 2, wherein the light-shielding laminate is cylindrical.
4. The light-shielding laminate according to any one of claims 1 to 3, wherein the shielding layer is a white ink layer.
5. The light-shielding laminate according to any one of claims 1 to 4, wherein the shielding layer is provided on both front and back sides of the base material.
6. Alkali-soluble 6. The light-shielding laminate according to any one of claims 1 to 5, further comprising an underlying layer containing a resin of .

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