JP7574601B2 - Metallic gloss prints - Google Patents

Description

The present invention relates to a printed matter having a metallic gloss layer containing metal flakes.

Such printed matter is described, for example, in Patent Document 1.

However, this print has high anti-glare properties, and as a result, the light reflection intensity in the specular reflection direction is reduced while the light reflection intensity in other reflective and diffuse directions is increased to provide a uniform light intensity overall. As a result, even when viewed from the specular reflection direction, the perceived brightness is low.

JP 2016-88095 A

Therefore, the present invention aims to provide a printed matter having a metallic luster layer containing metal flakes, which has a high sense of brilliance when observed from a specular reflection direction.

That is, the invention described in claim 1 is a printed matter comprising a metallic luster layer containing metal flakes provided on a substrate, and a surface protective layer provided on the outermost surface of the side having this metallic luster layer, wherein the value of X calculated according to the following formula (1) using the arithmetic mean roughness (Ra _0.08 ) of the surface of this surface protective layer when the cutoff value is 0.08 mm, the arithmetic mean roughness (Ra _0.25 ) of the surface of the surface protective layer when the cutoff value is 0.25 mm, and the arithmetic mean roughness (Ra _0.8 ) of the surface of the surface protective layer when the cutoff value is 0.8 mm is within the range of 2.0 to 4.0, and Ra _0.08 is 0.10 μm or more .

X=(Ra _0.8 - Ra _0.25 )/(Ra _0.25 - Ra _0.08 ) (1)
The invention described in claim 2 is the metallic gloss printed matter described in claim 1, characterized in that an anchor coat layer having a thickness of 1.0 to 3.0 μm is provided between the substrate and the metallic gloss layer. It is.

According to the present invention, even though the printed matter has a metallic gloss layer containing metal flakes, the light reflection intensity in the regular reflection direction is high, and therefore, when observed from this direction, a high sense of brightness can be observed.

FIG. 1 is a cross-sectional view of a specific example of a metallic gloss printed matter of the present invention.

Specific examples of the present invention will now be described with reference to the accompanying drawings. Figure 1 is a cross-sectional view of a specific example of a metallic gloss printed matter of the present invention.

As can be seen from Fig. 1, the present invention relates to a metallic gloss printed matter 10 comprising a metallic gloss layer 13 containing metal flakes provided on a substrate 11, and a surface protective layer 14 provided on the outermost surface on the side having the metallic gloss layer. In this example, an anchor coat layer 12 is provided between the substrate 11 and the metallic gloss layer 13. Other layers may be provided between the metallic gloss layer 13 and the surface protective layer 14, but when the printed matter 10 is observed from the surface protective layer 14 side, the metallic gloss layer 13 must be visible. An example of a layer provided between the metallic gloss layer 13 and the surface protective layer 14 is a partially printed picture print layer.

The printed matter of the present invention has a value of X calculated according to the following formula (1) for the surface of the surface protective layer 14 in the range of 2.0 to 4.0.

X=(Ra _0.8 - Ra _0.25 )/(Ra _0.25 - Ra _0.08 ) (1)
In this case, Ra _0.8 means the arithmetic mean roughness of the surface of the surface protective layer when the cutoff value is 0.08 mm. The arithmetic mean roughness Ra _0.8 is determined according to JIS B0601:2001. Similarly, Ra _0.25 means the arithmetic mean roughness of the surface of the surface protection layer when the cutoff value is 0.25 _mm . It means the arithmetic mean roughness of the surface of the surface protection layer when the surface roughness is set to 0.8 mm.

The cutoff value is a value that indicates the degree to which the waviness component (low frequency component) is cut from a cross-sectional curve that is composed of a roughness component (high frequency component) and a waviness component (low frequency component). In other words, the cutoff value is a value that indicates the fineness of the filter that cuts the waviness component (low frequency component). More specifically, when the cutoff value is large, the filter is coarse, so large waviness (low frequency component) among the waviness components is cut, but small waviness is not cut. In other words, when the cutoff value is large, the value includes the waviness component (low frequency component). On the other hand, when the cutoff value is small, the filter is fine, so most of the waviness component (low frequency component) is cut. In other words, when the cutoff value is small, the value includes almost no waviness component (low frequency component) and accurately reflects the roughness component (high frequency component).

For this reason, when the cutoff value is set to 0.08 mm, both the low frequency components and the medium frequency components are cut off as waviness, and the measured Ra of _0.08 reflects the high frequency components.

Furthermore, when the cutoff value is set to 0.25 mm, the low frequency components are cut off as waviness, so that the measured Ra of _0.25 reflects both the mid-frequency components and the high-frequency components.

Furthermore, when the cutoff value is set to 0.8 mm, the lower frequency components are cut off as waviness, but the relatively low frequency components, medium frequency components and high frequency components are reflected in Ra _0.8 .

For this reason, the numerator (Ra _0.8 - Ra _0.25 ) in formula (1) is a value reflecting the relatively low frequency components, while the denominator (Ra _0.25 - _{Ra 0.08} ) is a value reflecting the mid frequency components. Therefore, the value of X calculated according to formula (1) means the ratio of the value reflecting the relatively low frequency components to the value reflecting the mid frequency components of the surface unevenness of surface protection layer 14.

The reflected light in the regular reflection direction is caused by the relatively low frequency components of the surface irregularities of the surface protection layer 14, and the scattered reflected light that scatters around is caused by the mid and high frequency components of the irregularities, so a large value of X means that the light reflection intensity in the regular reflection direction is high. Therefore, when observed from this regular reflection direction, a high sense of brightness can be observed.

As described later, for the surface of the metallic luster layer 13, when considering an arithmetic mean roughness Ra _0.08 with a cutoff value of 0.08 mm, an arithmetic mean roughness Ra _0.25 with a cutoff value of 0.25 mm, an arithmetic mean roughness Ra _0.8 with a cutoff value of 0.8 mm, and a numerical value X calculated from these Ra _0.08 , Ra _0.25 , and Ra _0.8 according to formula (1), the metallic luster layer 13 is formed so that the numerical value X is in the range of 2.0 to 4.0, and then the surface protective layer 14 is formed so as to follow the surface irregularities of the metallic luster layer 13, it is possible to configure the surface of the surface protective layer 14 so that the value of X is also in the range of 2.0 to 4.0.

As the substrate 11, paper or plastic film can be used. Examples of paper include fine paper, medium-quality paper, coated paper, synthetic paper, impregnated paper, laminated paper, coated paper for printing, coated paper for recording, etc. Examples of plastic films include polyester film, polypropylene film, polystyrene film, nylon film, polycarbonate film, polyacrylonitrile film, polyimide film, etc. In addition, a multi-layered film in which films or papers of these various materials are laminated may be used, and further, a film provided with a vapor deposition layer or a printing layer may be used as the substrate film.

Next, by interposing an anchor coat layer 12 between the substrate 11 and the metallic luster layer 13, the light reflection intensity in the regular reflection direction can be increased. For this purpose, it is desirable for the anchor coat layer 12 to have a thickness of 1.0 to 3.0 μm. As can be seen by comparing the examples and comparative examples described below, if the anchor coat layer 12 is thicker than this, the value X represented by formula (1) becomes smaller, and therefore the light reflection intensity in the regular reflection direction cannot be increased.

The anchor coat layer 12 can be formed by applying an ionizing radiation curable resin composition and curing it by irradiating it with ionizing radiation.

The ionizing radiation curable resin composition is a composition containing a compound having an ionizing radiation curable functional group (hereinafter also referred to as "ionizing radiation curable compound"). Examples of the ionizing radiation curable functional group include ethylenically unsaturated bond groups such as (meth)acryloyl groups, vinyl groups, and allyl groups, as well as epoxy groups and oxetanyl groups. As the ionizing radiation curable compound, a compound having an ethylenically unsaturated bond group is preferred, a compound having two or more ethylenically unsaturated bond groups is more preferred, and among these, a polyfunctional (meth)acrylate-based compound having two or more ethylenically unsaturated bond groups is even more preferred. As the polyfunctional (meth)acrylate-based compound, either a monomer or an oligomer can be used, but a monomer is preferred from the viewpoint of improving scratch resistance and penetration resistance due to a high crosslinking density.

Ionizing radiation refers to electromagnetic waves or charged particle beams that have an energy quantum capable of polymerizing or crosslinking molecules. Usually, ultraviolet rays (UV) or electron beams (EB) are used, but other types of radiation, such as electromagnetic waves like X-rays and gamma rays, alpha rays, and charged particle beams like ion beams can also be used.

When the ionizing radiation curable compound is an ultraviolet ray curable compound, the ionizing radiation curable composition (ultraviolet ray curable resin composition) preferably contains a photopolymerization initiator. Examples include cetophenone, benzophenone, α-hydroxyalkylphenone, Michler's ketone, benzoin, benzyl methyl ketal, benzoyl benzoate, α-acyloxime ester, thioxanthones, etc.

Next, the metallic gloss layer 13 can be formed by mixing metal flakes, a resin binder, and other additives in a solvent to form a paint, and then applying this paint.

Materials for the metal flakes include metals and alloys such as aluminum, gold, silver, brass, titanium, chromium, nickel, nickel-chromium, and stainless steel.

The average length of the metal flakes is preferably 5.0 to 30 μm, and more preferably 8.0 to 20 μm. The average thickness of the metal flakes is preferably 0.10 μm or less, and more preferably 0.08 μm or less.

Such metal flakes can be produced, for example, by vacuum-depositing the metal or alloy onto a plastic film to form a thin metal film, peeling it off from the plastic film, and then crushing and stirring the peeled thin metal film.

Examples of resin binders include thermoplastic resins and thermosetting resins such as polyester resin, urethane resin, epoxy resin, melamine resin, alkyd resin, phenol resin, acrylic resin, and cellulose resin. In addition, a cured product of an ultraviolet-curable resin composition may be used as the resin binder.

The compounding ratio of the resin binder to the metal flakes is preferably 55:45 to 30:70 by mass solids ratio, and more preferably 50:50 to 35:65. By using 45 or more metal flakes to 55 resin binders, it becomes easier to obtain a sufficient metallic luster, and by using 70 or less metal flakes to 30 resin binders, it becomes easier to improve the printability of the metallic luster layer and the processability of the printed matter.

Other additives include, for example, colorants such as titanium oxide, zinc oxide, carbon black, iron oxide, iron yellow, ultramarine blue, metallic pigments, and pearl pigments. In addition, additives such as defoamers and thickeners can be added in the usual manner.

Also, ethanol, isopropyl alcohol, ethyl acetate, normal propyl acetate, etc. can be used as the solvent.

The thickness of the metallic gloss layer 13 is preferably 0.15 to 1.5 μm, and more preferably 0.20 to 1.0 μm.

The coating method can be a known coating method such as gravure coating, roll coating, or die coating.

It is desirable that the surface unevenness of the metallic gloss layer 13 thus formed is configured so that the numerical value X is in the range of 2.0 to 4.0. Then, by forming a surface protection layer 14 on the metallic gloss layer 13 that follows the surface unevenness of the metallic gloss layer 13, the surface unevenness of the surface protection layer 14 is also configured so that the value of X calculated according to formula (1) is in the range of 2.0 to 4.0.

Next, the surface protective layer 14 is located on the outermost surface of the printed matter 10, and improves its scratch resistance and weather resistance. In addition, the unevenness of the surface of the surface protective layer 14 controls the reflection direction of light incident on the printed matter 10, and increases the light reflection intensity in the regular reflection direction. Therefore, as described above, by forming the surface protective layer 14 following the metallic gloss layer 13 having surface unevenness with a numerical value X in the range of 2.0 to 4.0, the value of X on the surface can also be in the range of 2.0 to 4.0.

The surface protection layer 14 can be formed by applying a thermoplastic resin, a thermosetting resin, or an ultraviolet-curing resin, and then carrying out a required drying process, a heat curing process, or an ultraviolet ray irradiation process.

As the thermoplastic resin or thermosetting resin, acrylic resin, urethane resin, polyester resin, etc. can be used. As the ultraviolet-curable resin, a monomer having an ethylenically unsaturated bond group such as a (meth)acryloyl group, a vinyl group, or an allyl group, mixed with an additive such as a photopolymerization initiator or a photopolymerization accelerator can be used.

The surface protection layer 14 can be applied by known application methods such as gravure coating, roll coating, and die coating.

Example 1
Paper was used as the substrate 11, and an anchor coat layer 12, a metallic luster layer 13, and a surface protective layer 14 were applied thereon in this order to produce a metallic luster printed matter 10. The thickness of the anchor coat layer 12 was 2.2 μm. The surface of the surface protective layer of this printed matter 10 had an Ra of _0.8 of 0.39, an Ra of _0.25 of 0.18, an Ra of _0.08 of 0.10, and an X value of 2.63.

(Examples 2 to 3, Comparative Examples 1 to 4)
Metallic gloss printed matter 10 was produced in the same manner as in Example 1, except for changing the thickness of the anchor coat layer 12. The thickness of the anchor coat layer 12 of these metallic gloss printed matter 10, and the Ra _0.8 , Ra _0.25 , Ra _0.08 and X values of the surface of the surface protective layer are shown in Table 1.

When the printed matter of Examples 1 to 3 and Comparative Examples 1 to 4 was picked up and observed from various angles, the printed matter of Comparative Examples 1 to 4 did not change in brightness even when the observation angle was changed, and showed a uniform and stable metallic luster from any angle, whereas the printed matter of Examples 1 to 3 changed in brightness depending on the observation angle. When observed from the direction of regular reflection, a metallic luster with a particularly strong brightness was observed.

10: Metallic gloss print 11: Base material 12: Anchor coat layer 13: Metallic gloss layer 14: Surface protection layer

Claims (4)

A printed matter comprising a substrate having a metallic luster layer containing metal flakes and a surface protective layer on the outermost surface of the metallic luster layer side, wherein the value of X calculated according to the following formula (1) using the arithmetic mean roughness (Ra _0.08 ) of the surface of the surface protective layer when the cutoff value is set to 0.08 mm, the arithmetic mean roughness (Ra _0.25 ) of the surface of the surface protective layer when the cutoff value is set to 0.25 mm, and the arithmetic mean roughness (Ra _0.8 ) of the surface of the surface protective layer when the cutoff value is set to 0.8 mm is within a range of 2.0 to 4.0,
The Ra _0.08 is 0.10 μm or more;
Metallic gloss print.
X=(Ra _0.8 - Ra _0.25 )/(Ra _0.25 - Ra _0.08 ) (1) The Ra _0.8 is 0.47 μm or more,
The metallic gloss printed matter according to claim 1. The Ra _0.25 is 0.21 μm or more,
3. The metallic gloss printed matter according to claim 1 or 2. The metallic gloss printed matter according to claim 1, characterized in that it has an anchor coat layer having a thickness of 1.0 to 3.0 μm between the substrate and the metallic gloss layer.

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