WO2024070900A1

WO2024070900A1 - Decorative sheet

Info

Publication number: WO2024070900A1
Application number: PCT/JP2023/034355
Authority: WO
Inventors: 玲子桜井; 祥太西根; 亮介西垣; 昂秀齋藤
Original assignee: 大日本印刷株式会社
Priority date: 2022-09-29
Filing date: 2023-09-21
Publication date: 2024-04-04
Also published as: JP2024049531A; JP7338768B1; JP2024050426A

Abstract

Provided is a decorative sheet that can efficiently exhibit antiviral properties and can suppress deterioration of the antiviral properties over time.　The decorative sheet has a first surface and a second surface opposite to the first surface, and comprises, from the first surface toward the second surface, a protective layer, a decorative layer, and a base material in this order. The protective layer contains a binder resin and an antiviral agent. The first surface satisfies the following conditions 1 and 2. <Condition 1> Sdr, which is the developed area ratio of the interface according to ISO 25178-2:2012, is 0.500 or more. <Condition 2> The ratio RSm/Rz [wherein: RSm is the average length of the roughness curve element according to JIS B0601:2013; and Rz is the maximum height according to JIS B0601:2013] is 5.5 or less.

Description

Decorative sheet

This disclosure relates to decorative sheets.

Decorative sheets may be attached to the surfaces of articles such as interior building components such as walls, ceilings, and floors; exterior building components such as exterior walls, eaves ceilings, roofs, walls, and fences; fixtures or fittings such as window frames, doors, door frames, handrails, baseboards, moldings, and other building components; general furniture such as chests of drawers, shelves, and desks; kitchen furniture such as dining tables and sinks; surface decorative panels for cabinets and the like for home appliances and office automation equipment; and interior or exterior components for vehicles.
Decorative sheets are used for the purpose of imparting desired luster, design and texture to articles, for example.

In recent years, due to antibacterial trends and measures against various diseases such as influenza, decorative sheets are required to have antibacterial and antiviral properties in addition to the above-mentioned purposes.
Antiviral properties can be imparted, for example, by adding an antiviral agent to the protective layer located on the outermost surface of the decorative sheet. Antiviral decorative sheets have been proposed, for example, in

Patent Documents

1 and 2.

JP 2022-086989 A JP 2022-041927 A

The antiviral properties tend to increase as the amount of antiviral agent added increases. However, if the amount of antiviral agent added is increased too much, coloring due to the antiviral agent may occur and the coating properties of the protective layer may decrease.

Patent Documents

1 and 2 do not consider how to efficiently express antiviral properties.

In addition, the surface of the decorative sheet is often in contact with people's hands, feet, cleaning tools, etc. When the surface of the decorative sheet is rubbed by people's hands, feet, cleaning tools, etc., the antiviral agent may be detached from the surface of the decorative sheet, and the antiviral properties may decrease over time.

Patent Documents

1 and 2 do not consider at all the decrease in antiviral properties over time.

The objective of the present disclosure is to provide a decorative sheet that can efficiently exhibit antiviral properties and prevent the deterioration of antiviral properties over time.

In order to solve the above problems, the present disclosure provides the following decorative sheet.
A decorative sheet having a first surface and a second surface opposite to the first surface,
The decorative sheet has, from the first surface to the second surface, a protective layer, a decorative layer, and a base material in this order,
the protective layer comprises a binder resin and an antiviral agent,
The first surface of the decorative sheet satisfies the following

conditions

1 and 2.
<Condition 1>
The developed area ratio Sdr of the interface according to ISO 25178-2:2012 is 0.500 or more.
<Condition 2>
When the ratio of Rz, which is the maximum height in JIS B0601:2013, to RSm, which is the average length of the roughness curve element in JIS B0601:2013, is defined as RSm/Rz, RSm/Rz is 5.5 or less.

The present disclosure makes it possible to provide a decorative sheet that can efficiently exhibit antiviral properties and inhibit the deterioration of antiviral properties over time.

FIG. 1 is a cross-sectional view showing one embodiment of a decorative sheet of the present disclosure. FIG. 2 is a cross-sectional view showing another embodiment of the decorative sheet of the present disclosure. FIG. 1 is a schematic diagram showing a plan view of one embodiment of a decorative sheet of the present disclosure.

[Decorative sheet]
The decorative sheet of the present disclosure will be described below.

The decorative sheet of the present disclosure is
A decorative sheet having a first surface and a second surface opposite to the first surface,
The decorative sheet has, from the first surface to the second surface, a protective layer, a decorative layer, and a base material in this order,
the protective layer comprises a binder resin and an antiviral agent,
The first surface satisfies the following

conditions

The decorative sheets of the present disclosure are useful for antiviral applications.
In general, even for articles made of the same material and layer structure, the "antiviral" effect may not be correlated with the "antibacterial" and "antifungal" effects depending on various conditions. Examples of various conditions include the type of virus, the type of bacteria, the type of mold, and environmental conditions. For this reason, the decorative sheet of the present disclosure may be applicable not only to antiviral applications but also to antibacterial applications depending on the type of bacteria, environmental conditions, and the required level of antibacterial properties. Since mold is a type of fungus, the decorative sheet of the present disclosure may also be applicable to antifungal applications depending on the type of mold, environmental conditions, and the required level of antifungal properties.

1 and 2 are cross-sectional views showing an embodiment of a decorative sheet 1 of the present disclosure. Figures 1 and 2 are cross-sectional views of the decorative sheet 1 cut along a plane parallel to the thickness direction. The thickness direction of the decorative sheet 1 is the Z direction in Figures 1 and 2.
1 and 2, the decorative sheet 1 has, from the first surface to the second surface, a protective layer 4, a decorative layer 6, and a substrate 5, in this order. In Fig. 1 and Fig. 2, the upper surface is the first surface, and the lower surface is the second surface.
1 and 2, the decorative layer 6 is made up of two layers: a colored layer 6a and a pattern layer 6b.
The decorative sheet 1 in FIG. 2 has a primer layer 9 , a transparent resin layer 8 and an adhesive layer 7 in addition to a protective layer 4 , a decorative layer 6 and a substrate 5 .
1 and 2 are schematic cross-sectional views. That is, the scale of each layer constituting the decorative sheet 1 and the scale of the surface shape are schematic for ease of illustration and differ from the actual scale.
The decorative sheet of the present disclosure is not limited to the layered configuration of FIGS.

<Page 1>
The decorative sheet of the present disclosure has a first side. The first side of the decorative sheet is preferably used as the front side of the decorative sheet, which is the side that is viewed and touched by people.
In the decorative sheet of the present disclosure, the layer located on the outermost surface of the first surface side is preferably a protective layer.

The first surface of the decorative sheet must satisfy the following

conditions

Sdr can be expressed by the following formula, where A1 is the surface area of the first surface, and A0 is the area of the first surface projected onto the XY plane. It can be said that the larger Sdr is, the greater the rate of increase in the surface area of the first surface based on a smooth surface.
Sdr = (A1/A0) -1

When Sdr is large, the probability that the virus will come into contact with the antiviral agent is likely to increase. On the other hand, when Sdr is small, the probability that the virus will come into contact with the antiviral agent is likely to decrease. For this reason, when Sdr is less than 0.500 and condition 1 is not satisfied, the antiviral properties cannot be efficiently expressed. When the antiviral properties cannot be efficiently expressed, it takes a long time to bring the antiviral activity value to a predetermined value.
It is considered that even if the Sdr is less than 0.500, the antiviral properties can be improved by adding an excess amount of the antiviral agent. However, even if the antiviral agent is added in excess to a protective layer having an Sdr of less than 0.500, the antiviral properties cannot be efficiently expressed. In addition, when the antiviral agent is added in excess to the protective layer, a color due to the antiviral agent may be generated, or the coating film properties of the protective layer may be deteriorated.

The larger Sdr is, the more likely it is that the surface shape of the first surface is one in which wrinkles and other irregularities are densely arranged. When wrinkles and other irregularities are densely arranged, it becomes difficult for virus-containing sebum to penetrate into the recesses of the first surface, and there is a possibility that the antiviral properties may not be fully exhibited at the ridges and recesses of the wrinkles.
The Sdr of the first surface is preferably 0.500 or more and 1.500 or less, more preferably 0.700 or more and 1.250 or less, and further preferably 0.800 or more and 1.000 or less.

In the configuration elements shown in this specification, when multiple upper limit options and multiple lower limit options are shown, one selected from the upper limit options and one selected from the lower limit options can be combined to form an embodiment of the numerical range.
For example, in the case of the above Sdr, embodiments include numerical ranges such as 0.500 or more and 1.500 or less, 0.500 or more and 1.250 or less, 0.500 or more and 1.000 or less, 0.700 or more and 1.500 or less, 0.700 or more and 1.250 or less, 0.700 or more and 1.000 or less, 0.800 or more and 1.500 or less, 0.800 or more and 1.250 or less, and 0.800 or more and 1.000 or less.

The portions of the protective layer that are likely to come into contact with objects such as human hands and feet and cleaning tools are the convex portions of the protective layer. The greater the difference in elevation between the convex portions and concave portions of the protective layer, the less likely objects are to come into contact with the concave portions of the protective layer. Also, the narrower the interval between the convex portions and concave portions of the protective layer, the less likely objects are to come into contact with the concave portions of the protective layer.
A small RSm/Rz means that the interval between the unevenness such as wrinkles is narrow, and/or the elevation difference between the unevenness such as wrinkles is large. When RSm/Rz is small, objects are less likely to come into contact with the recesses of the protective layer, and the antiviral agent in the recesses is less likely to be released, so that the deterioration of antiviral properties over time can be easily suppressed. On the other hand, when RSm/Rz is large, objects are more likely to come into contact with the recesses of the protective layer, and the antiviral agent in the recesses is more likely to be released, so that the antiviral properties are more likely to decrease over time. Therefore, when RSm/Rz exceeds 5.5 and does not satisfy condition 2, the deterioration of antiviral properties over time cannot be suppressed.

An excessively small RSm/Rz means that the intervals between the irregularities such as wrinkles are excessively narrow, and/or the elevation difference between the irregularities such as wrinkles is excessively large. If the intervals between the irregularities such as wrinkles are excessively narrow, sebum containing viruses may not easily enter the recesses of the first surface, and the recesses may not be able to fully exhibit antiviral properties. If the elevation difference between the irregularities such as wrinkles is excessively large, cleaning tools such as cloths may be torn during cleaning.
The RSm/Rz of the first surface is preferably 3.0 or greater and 5.5 or less, more preferably 3.5 or greater and 5.3 or less, and even more preferably 4.0 or greater and 5.2 or less.

The first surface of the decorative sheet preferably has an Rz of 4.5 μm or more and 8.5 μm or less, more preferably 5.0 μm or more and 8.0 μm or less, and even more preferably 5.5 μm or more and 7.5 μm or less.
By setting Rz to 4.5 μm or more, condition 2 can be more easily satisfied, and therefore deterioration of antiviral properties over time can be more easily suppressed. By setting Rz to 8.5 μm or less, tearing of cleaning tools such as cloth during cleaning can be more easily suppressed.

The first surface of the decorative sheet preferably has an RSm of 20.0 μm or more and 50.0 μm or less, more preferably 22.0 μm or more and 45.0 μm or less, and even more preferably 25.0 μm or more and 40.0 μm or less.
By setting RSm to 20.0 μm or more, sebum containing viruses can easily penetrate into the recesses of the first surface, making it easier to more efficiently express antiviral properties. By setting RSm to 50.0 μm or less, it becomes easier to satisfy condition 2, making it easier to more easily suppress deterioration of antiviral properties over time.

The first surface of the decorative sheet preferably has an arithmetic mean roughness Ra according to JIS B0601:2013 of 0.6 μm or more and 1.5 μm or less, more preferably 0.7 μm or more and 1.3 μm or less, and even more preferably 0.8 μm or more and 1.1 μm or less.
By making the Ra at least 0.6 μm, the matte property of the decorative sheet can be easily improved. By making the Ra at most 1.5 μm, the decorative sheet can be more easily prevented from appearing whitish, which can reduce the design quality of the decorative sheet.

<Surface shape measurement method>
In this specification, the surface profile such as Sdr, RSm, Rz, and Ra is measured by a laser microscope. In measuring the surface profile using a laser microscope, the measurement area is 203.6 μm long × 271.5 μm wide. In measuring with the laser microscope, the objective lens is set to 50x.
In this specification, the values of the surface shape such as Sdr, RSm, Rz and Ra are the average values of the measurements at one arbitrary point on the surface shape of the decorative sheet and the other arbitrary eight points, for a total of nine points. The arbitrary nine points may be distant from each other, or may be close to or in contact with each other.
The value of Sdr in one measurement area is calculated from the entire measurement area. The values of RSm, Rz and Ra in one area are the average values of the measured values of a total of 15 cross sections obtained by measuring 8 cross sections in the vertical direction and 7 cross sections in the horizontal direction on the measurement screen corresponding to the measurement area. The intervals between the cross sections in the vertical and horizontal directions may be appropriately set within a range that does not become too narrow. The cutoff value for calculating RSm, Rz and Ra is 0.8 mm.
An example of a laser microscope capable of measuring the surface shape is a shape analysis laser microscope ("VK-X150 (control unit)/VK-X160 (measurement unit)", manufactured by Keyence Corporation).

<Layer structure>
The decorative sheet of the present disclosure has, from the first surface to the second surface, a protective layer, a decorative layer, and a substrate, in that order. The layer located on the outermost surface of the first surface side of the decorative sheet is preferably a protective layer.
The decorative sheet of the present disclosure may have layers other than the protective layer, the decorative layer, and the substrate. Examples of the layers other than the protective layer, the decorative layer, and the substrate include a primer layer, a transparent resin layer, and an adhesive layer. Examples of the laminated structure of the decorative sheet include the following (1) and (2).
(1) A configuration having a protective layer, a decorative layer, and a base material in this order from the first surface to the second surface.
(2) A configuration having, from the first surface to the second surface, a protective layer, a primer layer, a transparent resin layer, an adhesive layer, a decorative layer, and a substrate in this order.

Protective Layer
The protective layer contains a binder resin and an antiviral agent.
The protective layer in the decorative sheet of the present disclosure is preferably located on the outermost surface on the first surface side. The protective layer, for example, has a role of protecting the decorative layer and the substrate. In addition, the protective layer contains an antiviral agent, and thereby has a role of imparting antiviral properties to the decorative sheet.
The protective layer is preferably present on the entire surface of the decorative sheet when the decorative sheet is viewed in plan.

In order to make it easier to set Sdr within the above-mentioned range, the protective layer preferably has a surface shape in which the unevenness is densely arranged and the inclination angle of the unevenness is large. In order to make it easier to set RSm/Rz within the above-mentioned range, the protective layer preferably has a surface shape in which RSm is small and/or Rz is large. For this reason, the surface shape of the protective layer is preferably an uneven shape formed by wrinkles.
However, even if the surface shape of the protective layer has an uneven shape constituted by wrinkles, it is not necessarily possible to make Sdr and RSm/Rz within the above-mentioned range. In order to easily make Sdr and RSm/Rz within the above-mentioned range, it is important to increase the wrinkle density and the wrinkle elevation difference. In order to increase the wrinkle density and the wrinkle elevation difference by the method A2 described later, it is important that the curable resin composition forming the protective layer contains a predetermined polyfunctional monomer described later. However, if the elevation difference of the wrinkles is increased, the base of the convex portion may widen, so that RSm becomes large and RSm/Rz may not become small. Therefore, in order to easily make RSm/Rz within the above-mentioned range, it is important that the curable resin composition forming the protective layer contains a predetermined polyfunctional monomer described later, and the blending ratio of the polyfunctional monomer and the polyfunctional oligomer is a predetermined blending ratio described later.
In addition, a conventional general-purpose protective layer contains a binder resin and a matting agent, and forms an uneven shape based on the particle shape of the matting agent. Since it is difficult to form a dense uneven shape with a large inclination angle in a conventional general-purpose protective layer, it is difficult to set Sdr and RSm/Rz in the above-mentioned ranges.

A protective layer having Sdr and RSm/Rz in the above-mentioned ranges can be produced, for example, by the following method A1 or A2. In the case of the following method A2, it is important to adjust the blending of the binder resin composition and to control the wavelength when curing the binder resin composition.
A1: A surface shape in which Sdr and RSm/Rz are in the above range is created by simulation. A mold is created by etching or cutting the surface of the base material of the mold, such as a metal, so that the shape created by simulation is reflected. A protective layer can be obtained by pouring a composition for forming a protective layer into the mold and removing the composition from the mold. Alternatively, a protective layer can be obtained by applying a composition for forming a protective layer onto a substrate, pressing the mold against the substrate to form a shape, and peeling off the mold.
A2: A protective layer can be obtained by applying a composition for forming a protective layer, which contains a binder resin composition, an antiviral agent, and a wrinkle formation stabilizer, onto a substrate or a decorative layer, and curing the composition.

As an example of the wrinkles, there is a configuration shown in FIG.
Fig. 3 shows that the surface of the first side of the decorative sheet 1 has irregular wrinkles in a plan view. Fig. 3 also shows that the irregular wrinkles are configured by a plurality of convex portions 3 formed by a plurality of curved linear protrusions, and a concave portion 2 formed by being surrounded by the plurality of protrusions (the plurality of convex portions 3). Fig. 3 also shows that at least a portion of the curved plurality of convex portions 3 is formed by a meandering linear protrusion, and the meandering concave portion 2 is formed so as to be surrounded by the meandering linear protrusions.
In order to prevent interference and enhance a natural texture, it is preferable that the wrinkles are irregular in plan view. In addition, irregular wrinkles can suppress the reflected light from being biased toward a specific angle, making it easier to enhance the matte finish.

Here, "curved" means that there is one or more portions where the extension direction of the continuous linear protrusions 3 is reversed from one side to the other side in a plan view. Examples of portions where the extension direction is reversed from one side to the other side include, for example, a form in which, when the width of the plan view shape of the linear protrusions 3 is regarded as 0 and the linear protrusions 3 are approximated by a continuous curve, the continuous curve has an inflection point. In addition, examples of portions where the extension direction is reversed from one side to the other side include, for example, a form in which, when the width of the plan view shape of the linear protrusions 3 is ignored and the linear protrusions 3 are approximated by a straight line, the linear protrusions 3 have a portion that is approximated by a V-shaped folded line or two sides sandwiching one vertex of a triangle.
Moreover, "meandering" means that there are at least two or more portions where the extension direction of the continuous linear protrusions 3 is reversed from one side to the other side in a plan view (hereinafter also referred to as "reversed portions"), and when proceeding in the extension direction of the linear protrusions 3, there are portions where the extension direction of the linear protrusions 3 is reversed alternately in the opposite directions at two adjacent portions. For example, when the width of the plan view shape of the linear protrusions 3 is ignored and approximated by a continuous curve, examples of the shape include a form having a portion approximated by the Roman letter "S". Furthermore, when the width of the plan view shape of the linear protrusions 3 is ignored and approximated by a straight line, examples of the shape include a form having a portion approximated by the Roman letter "W".

In this specification, irregular means that the shape has a certain rule, and the shape is not patterned according to a certain rule. A typical example of a shape that is not irregular (regular shape) is a shape arranged with a certain periodicity in a specific direction, such as a so-called "lenticular lens" in which a plurality of cylindrical unit lenses are arranged adjacent to each other in a direction perpendicular to the longitudinal direction. Therefore, the irregular wrinkles in this embodiment include the shape of a single protrusion itself being irregular, not formed according to a certain rule such as periodicity, the shape of a plurality of convex parts formed by a plurality of protrusion parts being irregular, not formed and arranged according to a certain rule, and the shape of a concave part surrounded by such a plurality of protrusion parts being irregular.
The convex portions and concave portions that make up the irregular wrinkles may be irregular in any one of the shape of a single protrusion (single convex portion), the shape and arrangement of each of multiple protrusions (multiple protrusions), and the shape of a concave portion surrounded by multiple protrusions, but it is preferable that all of them are irregular.

The convex and concave portions in the uneven shape can be defined based on the median value of the height distribution in the uneven shape, with regions with heights exceeding this median value being convex portions, and regions with heights equal to or less than this median value being concave portions. For example, by utilizing the density difference (i.e., brightness difference) of an image having a density corresponding to the surface height of the protective layer of this embodiment, the darkest part of the density distribution image can be set to gradation 255, and the lightest part of the density distribution image can be set to gradation 0 (the median density value corresponding to the median height is 127). Then, for gradations 0 to 255, a binarization process can be performed to classify gradations 0 to 127 as concave portions and gradations 128 to 255 as convex portions.

- Binder resin -
In order to improve the scratch resistance of the protective layer, the binder resin preferably contains a cured product of a resin composition containing a curable resin, and more preferably contains a cured product of a resin composition containing an ionizing radiation curable resin.
Examples of the curable resin include thermosetting resins and ionizing radiation curable resins. Among them, ionizing radiation curable resins are preferred because they enhance the scratch resistance of the protective layer and also facilitate the formation of wrinkles.

The ionizing radiation curable resin is a resin having an ionizing radiation curable functional group, and the ionizing radiation curable functional group is a group that crosslinks and cures by irradiation with ionizing radiation, and preferable examples thereof include functional groups having an ethylenic double bond, such as a (meth)acryloyl group, a vinyl group, and an allyl group. In this specification, the (meth)acryloyl group refers to an acryloyl group or a methcroyl group. In addition, in this specification, the (meth)acrylate refers to an acrylate or a methacrylate.
In addition, ionizing radiation refers to electromagnetic waves or charged particle beams that have an energy quantum capable of polymerizing and/or crosslinking molecules. Usually, ultraviolet rays (UV) or electron beams (EB) are used, but other examples include electromagnetic waves such as X-rays and γ-rays, and charged particle beams such as α-rays and ion beams.

Examples of the ionizing radiation curable resin include electron beam curable resins and ultraviolet ray curable resins. Among these, ultraviolet ray curable resins, which are easy to form wrinkles, are preferred.
The ionizing radiation curable resin may be one or more selected from polymerizable monomers and polymerizable oligomers.

As the polymerizable monomer, a (meth)acrylate monomer having a radically polymerizable unsaturated group in the molecule is preferable, and among them, a polyfunctional (meth)acrylate monomer is preferable. Here, "(meth)acrylate" means "acrylate or methacrylate".
The polyfunctional (meth)acrylate monomer includes a (meth)acrylate monomer having two or more ionizing radiation-curable functional groups in the molecule, and having at least a (meth)acryloyl group as the functional group.

In order to make it easier to obtain the above surface shape, the number of functional groups of the polyfunctional (meth)acrylate monomer is preferably 2 or more and 4 or less, more preferably 2 or more and 3 or less, and even more preferably 2. The polyfunctional (meth)acrylate may be used alone or in combination of multiple types.

In order to make it easier to set Sdr and RSm/Rz within the above range, the polyfunctional (meth)acrylate monomer is preferably one having a certain distance between the (meth)acryloyl group and the (meth)acryloyl group. As the polyfunctional (meth)acrylate monomer having a certain distance between the (meth)acryloyl group and the (meth)acryloyl group, at least one monomer selected from the group consisting of an alkylene oxide-modified polyfunctional (meth)acrylate monomer and a caprolactone-modified polyfunctional (meth)acrylate monomer can be mentioned. These monomers can easily form wrinkles at a high density when cured because the modified site in the molecule is easy to move. The caprolactone-modified polyfunctional (meth)acrylate monomer is more likely to form wrinkles at a high density when cured than the alkylene oxide-modified polyfunctional (meth)acrylate monomer.
The total proportion of the alkylene oxide-modified polyfunctional (meth)acrylate monomer and the caprolactone-modified polyfunctional (meth)acrylate monomer relative to the total amount of the polyfunctional (meth)acrylate monomer is preferably 50 mass % or more, more preferably 60 mass % or more, and even more preferably 70 mass % or more.

The alkylene oxide-modified polyfunctional (meth)acrylate monomer has a unit represented by (-R ₁ -O-) _n in the polyfunctional (meth)acrylate monomer.
In the above unit, R ₁ represents a linear or branched alkylene group. R ₁ preferably has 2 to 4 carbon atoms, more preferably 2 to 3 carbon atoms, and even more preferably 2 carbon atoms.
In the above unit, n represents the average number of moles of alkylene oxide added. The average number of moles added is preferably 2 or more and 9 or less, more preferably 3 or more and 6 or less. By making the average number of moles added 2 or more, it is possible to easily form wrinkles at a high density during curing. By making the average number of moles added 9 or less, it is possible to easily suppress the deterioration of the scratch resistance of the protective layer.

The caprolactone-modified polyfunctional (meth)acrylate monomer has a structural unit [-C(=O)-(CH ₂ ) ₅ -O-] formed by ring-opening ε-caprolactone in the polyfunctional (meth)acrylate monomer.
The modified monomer preferably has 1 to 6, more preferably 2 to 4, of the above-mentioned open ring structures in the molecule. When the modified monomer has two or more of the above-mentioned open ring structures, the individual open ring structures may be connected to each other in the molecule, or may be located at separate positions in the molecule. By having one or more open ring structures, it is possible to easily form wrinkles at a high density during curing. By having 6 or less open ring structures, it is possible to easily suppress the deterioration of the scratch resistance of the protective layer.

The polyfunctional (meth)acrylate monomer preferably contains a polyfunctional glycerin (meth)acrylate monomer. By containing the polyfunctional glycerin (meth)acrylate monomer, the flexibility of the protective layer can be increased, and the scratch resistance of the decorative sheet can be easily increased. Examples of the polyfunctional glycerin (meth)acrylate monomer include glycerin di(meth)acrylate and glycerin tri(meth)acrylate.
For this reason, the polyfunctional (meth)acrylate monomer preferably contains the following (A) and (B).
(A) at least one monomer selected from the group consisting of an alkylene oxide-modified multifunctional (meth)acrylate monomer and a caprolactone-modified multifunctional (meth)acrylate monomer; (B) a multifunctional glycerin (meth)acrylate monomer;

The mixing ratio of (A) to (B) is preferably 10:1 to 1:1 by mass, and more preferably 5:1 to 2:1.

The ionizing radiation curable resin preferably uses a polymerizable monomer such as a polyfunctional (meth)acrylate monomer in combination with a polymerizable oligomer such as a polyfunctional (meth)acrylate oligomer. By using a polymerizable monomer in combination with a polymerizable oligomer, it is possible to easily adjust Sdr and RSm/Rz to be within the above ranges.
Polymerizable oligomers are less likely to form wrinkles than polymerizable monomers. For this reason, it is believed that the use of a polymerizable monomer and a polymerizable oligomer in combination reduces the number of wrinkle starting points. When the number of wrinkle starting points is reduced, the elevation difference between individual wrinkles tends to increase. For this reason, the use of a polymerizable monomer and a polymerizable oligomer in combination makes it easier to increase Rz and to satisfy condition 2. However, if the amount of polymerizable oligomer is increased too much, the number of wrinkle starting points is reduced and it becomes difficult to increase the surface area, making it difficult to satisfy condition 1. For this reason, the mass ratio of the polymerizable monomer to the polymerizable oligomer is preferably 5:5 to 9:1, and more preferably 6:4 to 8:2.

The polymerizable oligomer may, for example, be an oligomer having two or more ionizing radiation-curable functional groups in the molecule.
Examples of the polyfunctional (meth)acrylate oligomer include a urethane (meth)acrylate oligomer, an epoxy (meth)acrylate oligomer, a polyester (meth)acrylate oligomer, a polyether (meth)acrylate oligomer, a polycarbonate (meth)acrylate oligomer, and an acrylic (meth)acrylate oligomer.
Further, examples of the polymerizable oligomer include highly hydrophobic polybutadiene (meth)acrylate oligomers having (meth)acrylate groups in the side chains of polybutadiene oligomers, silicone (meth)acrylate oligomers having polysiloxane bonds in the main chains, aminoplast resin (meth)acrylate oligomers obtained by modifying aminoplast resins having many reactive groups in a small molecule, and oligomers having cationically polymerizable functional groups in the molecule, such as novolac type epoxy resins, bisphenol type epoxy resins, aliphatic vinyl ethers, and aromatic vinyl ethers.

The polymerizable oligomers may be used alone or in combination of two or more kinds.
Among the polymerizable oligomers, polyfunctional (meth)acrylate oligomers having two or more (meth)acryloyl groups in the molecule are preferred.
The polyfunctional (meth)acrylate oligomer is preferably a urethane (meth)acrylate oligomer, an epoxy (meth)acrylate oligomer, a polyester (meth)acrylate oligomer, a polyether (meth)acrylate oligomer, a polycarbonate (meth)acrylate oligomer, or an acrylic (meth)acrylate oligomer, more preferably a urethane (meth)acrylate oligomer or a polycarbonate (meth)acrylate oligomer, and even more preferably a urethane (meth)acrylate oligomer.

The lower limit of the number of functional groups of the polymerizable oligomer is preferably 2 or more, and the upper limit is preferably 8 or less, more preferably 6 or less, and even more preferably 4 or less. When the number of functional groups of the polymerizable oligomer is within the above range, it is easy to obtain the above-mentioned shape and to improve the strength of the decorative sheet.
The weight average molecular weight of the polymerizable oligomer is preferably 1,500 to 7,500, more preferably 1,700 to 5,000, and even more preferably 2,000 to 4,500. Here, the weight average molecular weight is an average molecular weight measured by GPC analysis and converted into standard polystyrene. When the weight average molecular weight of the polymerizable oligomer is within the above range, it is easy to obtain the above shape and to improve the strength of the decorative sheet.

When the ionizing radiation curable resin is an ultraviolet curable resin, it is preferable that the composition for forming the protective layer contains additives such as a photopolymerization initiator and a photopolymerization accelerator.

-Antiviral agent-
The antiviral agent may be an inorganic antiviral agent or an organic antiviral agent. The antiviral agent may be used alone or in combination of two or more kinds.

Examples of organic antiviral agents include the following (1) to (3). These organic antiviral agents are preferably present in the protective layer in the form of particles.
(1) Antiviral Agents Containing Imidazole Compounds (2) Antiviral Agents Containing Styrene Polymer Derivative Compounds and Unsaturated Carboxylic Acid Derivative Compounds (3) Antiviral Agents Containing Styrene Resins

(1) Antiviral Agent Containing Imidazole Compound Imidazole compounds are compounds containing an imidazole skeleton as a structural unit of the molecule. In the present disclosure, among various imidazole compounds, it is preferable to use one that maintains the particle shape in the protective layer. As imidazole compounds that easily maintain the particle shape, those that are difficult to dissolve in water and organic solvents are preferable, and examples thereof include methyl benzimidazol-2-ylcarbamate (also known as carbendazim) and polymerized imidazole compounds.
However, care should be taken because even methyl benzimidazol-2-yl carbamate (also known as carbendazim) and polymerized imidazole compounds may dissolve in certain solvents. For example, it is preferable to use methyl ethyl ketone, ethyl acetate, etc. as a solvent for methyl benzimidazol-2-yl carbamate (also known as carbendazim).

(2) Antiviral Agent Comprising a Styrene Polymer Derivative Compound and an Unsaturated Carboxylic Acid Derivative Compound In the present disclosure, the "antiviral agent comprising a styrene polymer derivative compound and an unsaturated carboxylic acid derivative compound" may be an "antiviral agent comprising a styrene polymer derivative compound and an unsaturated carboxylic acid derivative compound", or may be a "mixture of an antiviral agent comprising a styrene polymer derivative compound and an antiviral agent comprising an unsaturated carboxylic acid derivative compound", or may be a combination thereof.
The components of the styrene polymer derivative compound and the unsaturated carboxylic acid derivative compound preferably have at least one structure selected from the group consisting of styrene, sodium sulfonate, acrylic acid, maleic acid, and fumaric acid, and more preferably have both at least one structure of styrene and sodium sulfonate, and at least one structure selected from the group consisting of acrylic acid, maleic acid, and fumaric acid.

The content ratio of the styrene polymer derivative compound and the unsaturated carboxylic acid derivative compound in the antiviral agent is not limited, but the mass ratio is preferably 30:70 to 70:30, and more preferably 40:60 to 60:40. By setting the mass ratio in the above range, it is possible to easily exert antiviral properties against both enveloped and non-enveloped viruses. Note that, when exerting antiviral properties only against enveloped viruses, it is sufficient to contain only the styrene polymer derivative compound.

The reason why an antiviral agent containing a styrene polymer derivative compound and an unsaturated carboxylic acid derivative compound exhibits antiviral activity is thought to be as follows, although it is not limited to the mechanism speculated below.
Influenza viruses invade host cells by binding to sugar chain receptors (the sugar chain ends in neuraminic acid) on the surface of the host cells, but since the copolymer containing styrene sulfonate has an ionic group similar to that of neuraminic acid, it is believed that it binds to the virus instead of the host cell, captures the virus, and prevents the virus from binding to the host cell receptor, thereby exerting an antiviral effect. In addition, the unsaturated carboxylic acid derivative compound generates a hydroxyl group (OH-) when it comes into contact with moisture, and the hydroxyl group is believed to exert an antiviral effect.

(3) Antiviral Agent Containing Styrene Resin The antiviral agent containing a styrene resin is an antiviral agent that does not contain the unsaturated carboxylic acid derivative compound.

Inorganic antiviral agents include antiviral agents that support or contain metal ions on a carrier.
The metal ion is preferably any one of silver, zinc and copper, and more preferably silver.
As the carrier, inorganic compounds such as zeolite, apatite, glass, molybdenum, zirconium phosphate and titanium phosphate are preferred.

Zeolite is an aluminosilicate of alkali metals or alkaline earth metals, and both natural and synthetic zeolites can be used. Zeolites are also classified according to their crystal structure into A-type, faujasite type (X-type, Y-type), mordenite type, clinoptilolite type, etc., and any of these can be used.

Apatite is a general term for minerals having a composition represented by the following general formula.
_M10 ( _ZO4 ₎ _3X2
In the above formula, M represents Ca, Ba, Mg, Na, K, Fe, Al, etc., Z represents P, S, Si, As, etc., and X represents F, Cl, O, OH, etc. Representative examples that fall into the above formula include fluorapatite " _Ca10 ( _PO4 ) _6F2 " and _{hydroxyapatite} " _Ca10 ( _PO4 ) ₆ (OH) ₂ ".

Examples of the glass include soda glass, borosilicate glass, lead glass, aluminosilicate glass, borate glass, and phosphate glass.
Zirconium phosphate includes hexagonal zirconium phosphate.

The method for supporting or containing metal ions on a carrier may be appropriately selected from among commonly used methods. Here, "containing metal ions" means that metal ions or a substance capable of generating metal ions is held in a carrier in some form. In addition, "a substance capable of generating metal ions" means a substance that generates metal ions due to an external factor or a factor over time, such as a substance that generates metal ions by dissolving in water or the like.
Specific examples of the supported or infused form include a method of supporting by physical or chemical adsorption, a method of supporting by ion exchange, a method of supporting by a binder, a method of infusing a silver compound into a support, a method of supporting or infusing a silver compound by forming a thin layer on the surface of a support by a thin film forming method such as vapor deposition, dissolution-precipitation reaction, or sputtering, a method of ion exchanging a metal oxide such as glass at high temperature, etc. Among the above-mentioned forms, the method of supporting by ion exchange is preferred.

The antiviral agent is preferably in a particulate form to improve processability and to facilitate stabilization of the antiviral effect. There are no particular limitations on the particle shape, and examples of the particle shape include spheres, ellipsoids, polyhedrons, and scales.

In order to easily prevent the antiviral agent from being embedded in the protective layer, the average particle size of the antiviral agent is preferably 1 μm or more and 10 μm or less, more preferably 2 μm or more and 9 μm or less, and even more preferably 3 μm or more and 7 μm or less.
By making the average particle size 1 μm or more, the stability of the composition for forming the protective layer can be easily improved.
By setting the average particle size to 10 μm or less, it is possible to easily prevent the antiviral agent from protruding from the surface of the protective layer, which makes it possible to easily prevent deterioration of the appearance of the decorative sheet and to easily prevent wear on the members of the coating device, such as the coating roll and doctor blade.
In this specification, the average particle size of the antiviral agent and the wrinkle formation stabilizer means the value determined as the volume average value d50 by a laser diffraction method.

With regard to the content of the antiviral agent in the protective layer, the lower limit relative to 100 parts by mass of the binder resin is preferably 0.5 parts by mass or more, more preferably 1.0 part by mass or more, and more preferably 2.0 parts by mass or more, and the upper limit is preferably 20.0 parts by mass or less, more preferably 15.0 parts by mass or less, more preferably 10.0 parts by mass or less, more preferably 7.5 parts by mass or less, and more preferably 5.0 parts by mass or less.
By setting the content of the antiviral agent to 0.5 parts by mass or more, it is possible to easily exhibit the desired antiviral performance.
By setting the content of the antiviral agent to 20.0 parts by mass or less, it is possible to easily suppress the deterioration of the scratch resistance of the protective layer, and also to easily suppress the wear of the coating device components such as the coating roll and doctor blade. In addition, since the antiviral agent is not dissolved in the resin and is in a dispersed state, excessive addition of the antiviral agent causes the protective layer to become cloudy. By setting the addition amount as described above, it is possible to prepare a sheet that maintains the appearance of the decorative layer located under the protective layer.

- Wrinkle formation stabilizer -
When the protective layer is formed by the above-mentioned method A2, the composition for forming the protective layer preferably contains a wrinkle formation stabilizer.
The wrinkle formation stabilizer can stabilize the formation of irregular wrinkles on the surface of the protective layer.

As the wrinkle formation stabilizer, for example, organic particles or inorganic particles can be used.
Examples of organic substances constituting the organic particles include polymethyl methacrylate, acrylic-styrene copolymer resin, melamine resin, polycarbonate, polystyrene, polyvinyl chloride resin, benzoguanamine-melamine-formaldehyde condensate, silicone, fluorine-based resin, and polyester-based resin.
Examples of inorganic substances constituting the inorganic particles include silica, alumina, calcium carbonate, aluminosilicate, and barium sulfate. Among these, silica, which has excellent transparency, is preferred.
Among the above-mentioned wrinkle formation stabilizers, silica is preferred.
The shape of the wrinkle formation stabilizer may be spherical, polyhedral, scaly, irregular, or the like.

The wrinkle formation stabilizer is preferably one in which the ratio d/t, which is the ratio of the average particle diameter d of the wrinkle formation stabilizer to the thickness t of the protective layer, is 0.10 or more and 0.80 or less, more preferably 0.12 or more and 0.70 or less, and even more preferably 0.15 or more and 0.60 or less.
The preferred range of the average particle diameter d of the wrinkle formation stabilizer depends on the thickness t of the protective layer, but is preferably 1.0 μm or more and 15.0 μm or less, more preferably 1.5 μm or more and 10.0 μm or less, and even more preferably 2.0 μm or more and 9.0 μm or less.

The wrinkle formation stabilizer preferably contains two types of wrinkle formation stabilizers with different average particle diameters. When the average particle diameter of the wrinkle formation stabilizer with the larger average particle diameter is d1 and the average particle diameter of the wrinkle formation stabilizer with the smaller average particle diameter is d2, d1/d2 is preferably 1.5 to 4.0, more preferably 2.0 to 3.5, and even more preferably 2.5 to 3.0. Both d1/t and d2/t are preferably 0.10 to 0.80.
The content ratio of the wrinkle formation stabilizer having a larger average particle size to the wrinkle formation stabilizer having a smaller average particle size, on a mass basis, is preferably 1:3 to 3:1, and more preferably 1:2 to 2:1.
As described above, by including two types of wrinkle formation stabilizers with different average particle diameters, wrinkles are stably formed in the protective layer, making it easier to satisfy

conditions

1 and 2. The reason for this is believed to be that the wrinkle formation stabilizer with the larger average particle diameter becomes the starting point of wrinkles, and further, the wrinkle formation stabilizer with the smaller average particle diameter finely disperses and stabilizes the wrinkles that are formed with the wrinkle formation stabilizer with the larger average particle diameter as the starting point.

The content of the wrinkle formation stabilizer is preferably 0.5 parts by mass or more, more preferably 1.0 parts by mass or more, and even more preferably 3.0 parts by mass or more, and the upper limit is preferably 15.0 parts by mass or less, more preferably 10.0 parts by mass or less, and even more preferably 7.0 parts by mass or less, relative to 100 parts by mass of the binder resin.

The thickness t of the protective layer is not particularly limited, but when the protective layer is formed by the above-mentioned method A2, it is preferable that the thickness t is in the range such that d/t falls within the above-mentioned range.
In an embodiment of the thickness t of the protective layer, the lower limit is 1 μm or more, preferably 2 μm or more, more preferably 3 μm or more, even more preferably 4 μm or more, and still more preferably 5 μm or more, and the upper limit is preferably 100 μm or less, more preferably 50 μm or less, even more preferably 30 μm or less, and still more preferably 20 μm or less.
In this specification, the thickness of each layer constituting the decorative sheet, such as a protective layer, is determined by measuring the thickness at 20 points on an image of a cross section of the decorative sheet taken with a scanning electron microscope (SEM), and averaging the values at 20 points.

The protective layer may contain additives such as antioxidants, light stabilizers, UV absorbers, anti-wear agents, and surface conditioners to the extent that they do not impair the effects of the present disclosure.

Decorative Layer
The decorative sheet of the present disclosure has a decorative layer to improve design. The decorative layer is a layer provided between the substrate and the protective layer. In addition, when the decorative sheet has a transparent resin layer described later, the laminated structure of the decorative sheet is preferably in the order of the protective layer, the transparent resin layer, the decorative layer, and the substrate.

The decorative layer may be, for example, a colored layer covering the entire surface, or a pattern layer formed by printing various patterns using ink and a printing machine. Here, the "colored layer covering the entire surface" is also called a "solid colored layer" and is a layer indicated by "6a" in Figures 1 and 2, and the "pattern layer" is indicated by "6b" in Figures 1 and 2. As shown in Figures 1 and 2, the decorative layer may be a combination of a solid colored layer and a pattern layer.
The decorative layer may also be a thin metal film.

Patterns for the pattern layer include wood grain patterns such as tree rings and vessel grooves on the surface of a wooden board, stone grain patterns on the surface of stone slabs such as marble and granite, fabric grain patterns on the surface of fabric, leather grain patterns on the surface of leather, geometric patterns, letters, and figures, and may be combinations of these.

The ink used for the decorative layer is a suitable mixture of a binder resin, a colorant such as a pigment or dye, an extender pigment, a solvent, a stabilizer, a plasticizer, a catalyst, a hardener, an ultraviolet absorber, a light stabilizer, etc.
The binder resin of the decorative layer is not particularly limited, and examples thereof include urethane resin, acrylic polyol resin, acrylic resin, ester resin, amide resin, butyral resin, styrene resin, urethane-acrylic copolymer, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-acrylic copolymer resin, chlorinated propylene resin, nitrocellulose resin, cellulose acetate resin, etc. In addition, various types of resins can be used, such as one-component curing resins and two-component curing resins accompanied by a curing agent such as an isocyanate compound.

As the colorant, a pigment having excellent hiding power and weather resistance is preferable. The pigment may be the same as those exemplified as the pigments that can be used for the substrate.
The content of the colorant is preferably 5 parts by mass or more and 90 parts by mass or less, more preferably 15 parts by mass or more and 80 parts by mass or less, and even more preferably 30 parts by mass or more and 70 parts by mass or less, relative to 100 parts by mass of the resin constituting the decorative layer.

The decorative layer may contain additives such as weather resistance agents, such as ultraviolet absorbers and light stabilizers, and colorants.
The thickness of the decorative layer may be appropriately selected according to the desired pattern, but in order to improve the design, it is preferably 0.5 μm to 20 μm, more preferably 1 μm to 10 μm, and even more preferably 2 μm to 5 μm. When it is necessary to conceal the color and appearance of the adherend, the thickness of the decorative layer is preferably 1.5 μm or more, although it depends on the type and content of the colorant contained.

"Base material"
Examples of materials constituting the substrate include paper, nonwoven fabric, woven fabric, and resin.

Examples of the paper base material include kraft paper, titanium paper, linter paper, parchment paper, glassine paper, parchment paper, resin-impregnated paper, tissue paper, and Japanese paper.
Examples of fibers constituting the nonwoven or woven fabric substrate include at least one type selected from inorganic fibers made of inorganic materials such as glass, alumina, silica, and carbon; and organic fibers made of synthetic resins such as polyester resin, acrylic resin, polyethylene, and polypropylene.

Examples of resin substrates include polyolefin resins such as polypropylene, polyethylene, polyolefin thermoplastic elastomers, and ionomers; polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), ethylene glycol-terephthalic acid-isophthalic acid copolymers, and polyester thermoplastic elastomers; acrylic resins such as polymethyl (meth)acrylate, polybutyl (meth)acrylate, and methyl (meth)acrylate-butyl (meth)acrylate copolymers; polyester resins; polycarbonate resins; acrylonitrile-butadiene-styrene resins; and vinyl chloride resins.

The substrate may contain additives such as colorants, flame retardants, antioxidants, lubricants, foaming agents, antioxidants, UV absorbers, and light stabilizers.

The substrate may be a single type of substrate, or a composite substrate made by layering two or more types of substrates.

The thickness of the substrate is not particularly limited and may be appropriately determined depending on the desired performance.
In the case of a resin substrate, the lower limit of the thickness is preferably 20 μm or more, more preferably 40 μm or more, and the upper limit is preferably 300 μm or less, more preferably 200 μm or less, and further preferably 100 μm or less.
In the case of a paper base material, the basis weight is preferably from 20 g/m ² to 150 g/m ² , and more preferably from 30 g/m ² to 100 g/m ² .

The substrate may be subjected to a surface treatment such as physical surface treatment such as oxidation or roughening, or chemical surface treatment, on one or both sides in order to enhance adhesion with the protective layer, etc. Also, an easy-adhesion layer may be provided between the substrate and the protective layer.

Other Layers
The decorative sheet of the present disclosure may have layers other than the protective layer, decorative layer, and substrate. Examples of layers other than the protective layer, decorative layer, and substrate include a primer layer, a transparent resin layer, and an adhesive layer.
The decorative sheet 1 in FIG. 2 has, from the first surface to the second surface, a protective layer 4, a primer layer 9, a transparent resin layer 8, an adhesive layer 7, a decorative layer 6, and a substrate 5 in this order.

(Primer layer)
The primer layer is formed, for example, to improve interlayer adhesion.
The primer layer may be formed, for example, between the protective layer and the decorative layer, between the decorative layer and the substrate, or between the transparent resin layer and the protective layer.

The primer layer is mainly composed of a binder resin, and may contain additives such as ultraviolet absorbers and light stabilizers as necessary.

Preferred examples of the binder resin include urethane resin, acrylic polyol resin, acrylic resin, ester resin, amide resin, butyral resin, styrene resin, urethane-acrylic copolymer, polycarbonate-based urethane-acrylic copolymer (urethane-acrylic copolymer derived from a polymer (polycarbonate polyol) having a carbonate bond in the polymer main chain and having two or more hydroxyl groups at the terminal and side chain), vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-acrylic copolymer resin, chlorinated propylene resin, nitrocellulose resin (nitrocellulose), and cellulose acetate resin. These may be used alone or in combination of two or more kinds.
The binder resin may be a resin obtained by adding a curing agent such as an isocyanate-based curing agent or an epoxy-based curing agent to the resin and crosslinking and curing it. Among these, a polyol-based resin such as an acrylic polyol resin is preferably crosslinked and cured with an isocyanate-based curing agent, and an acrylic polyol resin is more preferably crosslinked and cured with an isocyanate-based curing agent.

The thickness of the primer layer is preferably 0.1 μm or more and 10 μm or less, more preferably 1 μm or more and 8 μm or less, and even more preferably 2 μm or more and 6 μm or less.

(Transparent Resin Layer)
The transparent resin layer is formed in order to increase the strength of the decorative sheet and to protect the decorative layer. In order to protect the decorative layer, the transparent resin layer is preferably formed between the decorative layer and the protective layer.

The resins constituting the transparent resin layer include polyolefin resins, polyester resins, polycarbonate resins, acrylonitrile-butadiene-styrene resins (hereinafter also referred to as "ABS resins"), acrylic resins, vinyl chloride resins, etc., of which polyolefin resins and vinyl chloride resins are preferred from the standpoint of suitability for post-processing, etc. Furthermore, two or more of these various resins may be laminated or mixed for use.

The transparent resin layer only needs to be transparent enough to allow the decorative layer to be visually recognized, and may be colorless transparent, colored transparent, or translucent. In other words, in this specification, "transparent" means colorless transparent, colored transparent, and translucent.

The transparent resin layer may contain additives such as weather resistance agents, including ultraviolet absorbers and light stabilizers, and colorants.
Considering protection of the decorative layer, suitability for post-processing, and the like, the thickness of the transparent resin layer is preferably from 20 μm to 150 μm, more preferably from 40 μm to 120 μm, and even more preferably from 60 μm to 100 μm.

(Adhesive Layer)
When the decorative sheet of the present disclosure has a substrate and a transparent resin layer, an adhesive layer may be provided between the substrate and the transparent resin layer in order to improve adhesion between the two layers.
The positional relationship between the adhesive layer and the decorative layer is not particularly limited, and specifically, the adhesive layer may have a decorative layer, an adhesive layer, and a transparent resin layer in this order from the side closest to the substrate, or the adhesive layer, a decorative layer, and a transparent resin layer in this order from the side closest to the substrate.

The adhesive layer can be made of, for example, an adhesive such as a urethane adhesive, an acrylic adhesive, an epoxy adhesive, a rubber adhesive, etc. Among these adhesives, a urethane adhesive is preferred in terms of adhesive strength.
Examples of urethane-based adhesives include adhesives that utilize two-component curing urethane resins that contain various polyol compounds, such as polyether polyols, polyester polyols, and acrylic polyols, and a curing agent, such as an isocyanate compound.

The thickness of the adhesive layer is preferably 0.1 μm or more and 30 μm or less, more preferably 1 μm or more and 15 μm or less, and even more preferably 2 μm or more and 10 μm or less, in order to efficiently obtain the desired adhesive strength.

<Optical properties>
The decorative sheet of the present disclosure has a decorative layer. When the decorative sheet has high transparency, the design of the decorative layer may be reduced by an object located behind the decorative sheet. To prevent this, the decorative sheet of the present disclosure may use a non-transparent material as the substrate. For this reason, the decorative sheet of the present disclosure has a total light transmittance according to JIS K7361-1:1997 of preferably 20% or less, more preferably 15% or less, and even more preferably 10% or less.
In this specification, the total light transmittance of a decorative sheet is the average value of measurements taken at any ten points.

The decorative sheet of the present disclosure preferably has a 60 degree specular gloss according to JIS Z8741:1997 of 1.0 or more and 20.0 or less, more preferably 1.0 or more and 10.0 or less, and even more preferably 1.0 or more and 5.0 or less, of the first surface.
The decorative sheet of the present disclosure preferably has an 85 degree specular gloss according to JIS Z8741:1997 of the first surface of 7.0 or more and 25.0 or less, more preferably 7.5 or more and 23.0 or less, and even more preferably 8.0 or more and 20.0 or less.
By setting the 60° specular gloss and 85° specular gloss to a predetermined value or less, the matte property of the decorative sheet can be easily improved. By setting the 60° specular gloss and 85° specular gloss to a predetermined value or more, problems caused by too large Sdr and problems caused by too small RSm/Rz can be easily suppressed.
In this specification, the 60 degree specular gloss and the 85 degree specular gloss are the average values of measurements taken at 10 points.

[Method of manufacturing decorative sheet]
A first method for producing a decorative sheet according to the present disclosure comprises a decorative layer forming step of providing a decorative layer on a substrate, and a protective layer forming step on the decorative layer.
The steps of forming the protective layer include the above-mentioned steps A1 and A2. The above-mentioned step A2 will be described in more detail below.

The protective layer can be formed, for example, by applying a composition for forming a protective layer, which contains a binder resin composition, an antiviral agent, and a wrinkle formation stabilizer, onto the decorative layer, and curing the composition.
After the composition for forming the protective layer is applied, it is preferable to cure the binder resin composition by irradiating it with light having a wavelength of at least 100 nm or more and 380 nm or less.

In the manufacturing method of the decorative sheet disclosed herein, when forming the protective layer, it is important to irradiate the composition that forms the protective layer with ultraviolet light having a short wavelength of at least 100 nm or more and 380 nm or less. By irradiating the composition with ultraviolet light having a short wavelength and curing it, irregular wrinkles can be formed on the surface of the protective layer.

The details of the mechanism by which wrinkles form on the surface of a protective layer when the composition for forming the protective layer is irradiated with such low-wavelength ultraviolet light are unknown, but it is presumed to be due to the following mechanism.

When a coating layer of a protective layer-forming composition applied to a specified thickness is irradiated with low-wavelength ultraviolet light, the energy of the ultraviolet light penetrates only the surface portion and does not reach the layers below, so only the surface portion of the composition containing the curable resin begins to harden. As a result, only the surface undergoes hardening shrinkage, which is thought to be the cause of the formation of irregular wrinkles. In this way, it is thought that the formation of irregular wrinkles occurs when the protective layer-forming composition is hardened only in a certain thickness direction from the surface due to irradiation with low-wavelength ultraviolet light.

Furthermore, in the comparative examples described below, Comparative Examples 4 and 5, which do not contain a wrinkle formation stabilizer, the formation of irregular wrinkles is unstable. For this reason, in order to stably form irregular wrinkles, it is essential that a wrinkle formation stabilizer is included.

In the manufacturing method disclosed herein, the composition for forming the protective layer is irradiated with light having a wavelength of at least 100 nm or more and 380 nm or less. As a result of this irradiation, as described above, the energy of the ultraviolet light penetrates only the surface portion, and the energy does not reach the layers below, so that only the surface portion of the composition containing the curable resin begins to harden. As a result, curing shrinkage occurs only on the surface, and irregular wrinkles are stably formed. Then, curing progresses from the surface-nearby portion, where curing progresses slowly, to the deep portion away in the depth direction, and the layer of the composition containing the curable resin becomes a cured product. In order to promote the progress of curing to the deep portion, it is preferable to perform another irradiation process after irradiation with light having a wavelength of at least 100 nm and no more than 380 nm, as described below.

As the light having a wavelength of at least 100 nm or more and 380 nm or less, for example, a rare gas such as Ar, Kr, Xe, Ne, a halogenated rare gas such as F, Cl, I, Br, or a mixed gas thereof is preferably used, such as an excited dimer formed by discharging the gas, i.e., an excimer, which is an "excimer light" including light in the ultraviolet wavelength region. As the wavelength of the excimer light and the excimer serving as the light source, for example, light having a wavelength of 126 nm radiated from the excimer of _Ar2 (hereinafter, abbreviated as "126 nm ( _Ar2 )"), 146 nm ( _Kr2 ), 157 nm ( _F2 ), 172 nm ( _Xe2 ), 193 nm (ArF), 222 nm (KrCl), 247 nm (KrF), 308 nm (XeCl), 351 nm (XeF), and the like can be preferably used. As the excimer light, either spontaneous emission light or laser light with high coherence due to stimulated emission can be used, but the use of spontaneous emission light is usually sufficient. Discharge lamps that emit light (ultraviolet rays) are also called "excimer lamps".
Excimer light has a single wavelength peak and is characterized by a narrower half-width wavelength than ordinary ultraviolet light (e.g., ultraviolet light emitted from metal halide lamps, mercury lamps, etc.). By using such excimer light, the formation of irregular wrinkles is stabilized.

In order to stabilize the formation of irregular wrinkles, the wavelength is preferably 120 nm or more, more preferably 140 nm or more, even more preferably 150 nm or more, and even more preferably 155 nm or more, with the upper limit being preferably 320 nm or less, more preferably 300 nm or less, even more preferably 250 nm or less, even more preferably 200 nm or less, and most preferably 172 nm (Xe ₂ ). Thus, in the present disclosure, in order to stably form wrinkles, it is preferable to use light with a shorter wavelength, and it can be said that medium wavelength ultraviolet light (wavelength: 280 to 320 nm) and short wavelength ultraviolet light (wavelength: 280 nm or less) are more preferable, and short wavelength ultraviolet light is even more preferable.

In the present disclosure, the integrated light amount of the above wavelength light is preferably 1 mJ/cm ² or more, more preferably 10 mJ/cm ² or more, even more preferably 30 mJ/cm ² or more, and even more preferably 50 mJ/cm ² or more in order to stabilize the formation of irregular wrinkles. There is no particular limit to the upper limit, and in consideration of reducing the number of lamps required for irradiation of the wavelength light and improving productivity such as improving production efficiency, it is preferably 1,000 mJ/cm ² or less, more preferably 500 mJ/cm ² or less, and even more preferably 300 mJ/cm ² or less. For the same reason, the ultraviolet light output density is preferably 0.001 W/cm 2 or more, more preferably 0.01 W/cm 2 or more, and even more preferably 0.03 W/cm 2, and the upper limit is preferably 10 W/cm 2 or less, more preferably 5 W/cm 2 or less, and even more preferably 3 W/cm 2 or less.
In addition, the oxygen concentration during irradiation with light of the above wavelengths is preferably lower, and is preferably 1,000 ppm or less, more preferably 750 ppm or less, even more preferably 500 ppm or less, and even more preferably 300 ppm or less.

In the protective layer forming step in the decorative sheet manufacturing method of the present disclosure, in addition to the above-mentioned irradiation with light having a wavelength of at least 100 nm or more and 380 nm or less, other treatments that contribute to curing the composition for forming the protective layer may be carried out.
For example, in order to stabilize the formation of irregular wrinkles due to the difference in the degree of progress of curing between the surface portion and the deep portion distant from the surface in the depth direction and to promote the progress of curing to the deep portion, for example, the composition for forming the protective layer may be pre-cured as a whole by irradiating with light having a wavelength of more than 380 nm, preferably light having a wavelength of about 385 nm to 400 nm, and then irradiated with light having a wavelength of 100 nm to 380 nm or less, or after irradiation with light having a wavelength of 100 nm to 380 nm, post-curing may be performed to further cure the composition containing the curable resin. Regarding pre-curing and post-curing, the necessity of their adoption may be appropriately determined depending on the desired properties required for the protective layer. In addition, although the above-mentioned wavelength light belongs to ultraviolet rays, it is also possible to use other ionizing radiations other than ultraviolet rays, such as electron beams. For example, in post-curing, electron beams may be preferably used from the viewpoint of improving the surface properties of the protective layer.

In the manufacturing method disclosed herein, the protective layer can be formed by irradiating a coating layer (uncured resin layer) in which a composition for forming the protective layer has been applied by a known method such as an inkjet method, gravure printing method, bar coating method, roll coating method, reverse roll coating method, or comma coating method, with light having a wavelength of at least 100 nm or more and 380 nm or less.

The decorative sheet of the present disclosure can be used for the following applications (1) to (12).
(1) Surface materials for interior parts such as walls, floors, and ceilings of buildings such as houses, offices, stores, hospitals, and clinics.
(2) Surface materials for exterior parts such as exterior walls, roofs, eaves ceilings, door pockets, etc. of buildings such as houses, offices, stores, hospitals, and clinics.
(3) Surface materials for building fixtures such as windows, window frames, doors, and door frames (interior or exterior parts); surface materials for accessories of building fixtures (handles, etc.); surface materials for building fixtures.
(4) Surface materials for construction components such as handrails, waist walls, moldings, thresholds, lintels, and top boards.
(5) Surface materials for outdoor (exterior) parts such as fences, gates, drying rack pillars and handrails.
(6) Surface materials for furniture such as chests of drawers, desks, chairs, cupboards, kitchen sinks, etc.; surface materials for furniture accessories (handles, etc.); surface materials for furniture fixtures.
(7) Surface materials for the housings of various home electrical appliances such as television receivers, radio receivers, refrigerators, microwave ovens, washing machines, electric fans, air conditioners, telephones, etc.; surface materials for accessories of home electrical appliances (handles, switches, etc.); surface materials for fixtures of home electrical appliances.
(8) Surface materials for office equipment such as various computing devices such as electronic copiers, facsimiles, printers, and personal computers; surface materials for the housings of various office equipment such as ATM devices at financial institutions such as banks and post offices; surface materials for accessories of various office equipment (keyboards, etc.); surface materials for tools of various office equipment.
(9) Surface materials for the interior or exterior parts (walls, floors, ceilings, handrails, supports, control panels, levers, handles, steering wheels, and other control equipment) of vehicles such as automobiles, railway cars, ships, and aircraft.
(10) Partitions in various buildings; shielding panels or curtains to prevent droplet infection of viruses at counters and accounting counters of stores, offices, government offices, etc.; or surface materials thereof.
(11) Business forms such as slips; bankbooks; cards such as cash cards, credit cards, and point cards of financial institutions; or the surface materials thereof.
(12) Glass, resin, etc. bottles; metal cans; resin soft packaging materials such as resin retort containers; packaging materials such as various tubes; or surface materials thereof.

[Decorative materials]
The decorative member of the present disclosure is formed by attaching the above-mentioned decorative sheet of the present disclosure onto an article.
Examples of the article include the articles exemplified for use as decorative sheets.

The present disclosure includes the following [1] to [12].
[1] A decorative sheet having a first surface and a second surface opposite to the first surface,
The decorative sheet has, from the first surface to the second surface, a protective layer, a decorative layer, and a base material in this order,
the protective layer comprises a binder resin and an antiviral agent,
The first surface of the decorative sheet satisfies the following

conditions

1 and 2.
<Condition 1>
The developed area ratio Sdr of the interface according to ISO 25178-2:2012 is 0.500 or more.
<Condition 2>
When the ratio of Rz, which is the maximum height in JIS B0601:2013, to RSm, which is the average length of the roughness curve element in JIS B0601:2013, is defined as RSm/Rz, RSm/Rz is 5.5 or less.
[2] The decorative sheet according to [1], wherein, in Condition 1, Sdr is 0.500 or more and 1.500 or less.
[3] The decorative sheet according to [1] or [2], wherein, in condition 2, RSm/Rz is 3.0 or more and 5.5 or less.
[4] The decorative sheet according to any one of [1] to [3], wherein the first surface has a maximum height Rz according to JIS B0601:2013 of 4.5 μm or more and 8.5 μm or less.
[5] The decorative sheet according to any one of [1] to [4], wherein the first surface has a roughness curve element average length RSm according to JIS B0601:2013 of 20.0 μm or more and 50.0 μm or less.
[6] The decorative sheet according to any one of [1] to [5], wherein the first surface has an arithmetic average roughness Ra according to JIS B0601:2013 of 0.6 μm or more and 1.5 μm or less.
[7] The decorative sheet according to any one of [1] to [6], wherein the decorative sheet has a protective layer on the entire surface thereof when viewed in plan.
[8] The decorative sheet according to any one of [1] to [7], comprising 0.5 parts by mass or more and 20.0 parts by mass or less of the antiviral agent per 100 parts by mass of the binder resin.
[9] The decorative sheet according to any one of [1] to [8], wherein the binder resin comprises a cured product of a resin composition containing a curable resin.
[10] The decorative sheet according to any one of [1] to [9], wherein the layer located on the outermost surface of the first surface side is the protective layer.
[11] The decorative sheet according to any one of [1] to [10], wherein the 60 degree specular gloss of the first surface according to JIS Z8741:1997 is 1.0 or more and 20.0 or less, and the 85 degree specular gloss of the first surface according to JIS Z8741:1997 is 7.0 or more and 25.0 or less.
[12] The decorative sheet according to any one of [1] to [11], having a total light transmittance according to JIS K7361-1:1997 of 20% or less.

Next, the present disclosure will be explained in more detail using examples, but the present disclosure is not limited to these examples.

1. Measurement and Evaluation 1-1. Measurement of Surface Shape The surface shape (Sdr, RSm, Rz and Ra) of the first side of the decorative sheets obtained in the Examples and Comparative Examples was measured using a laser microscope. A total of nine points were measured, including one arbitrary point on the surface shape of the decorative sheet and eight adjacent points, and the average value of the measurements at the nine points was taken as the surface shape (Sdr, RSm, Rz and Ra) of each decorative sheet. The measurement area at one point was 203.6 μm long x 271.5 μm wide.
The Sdr value of one measurement area was calculated from the entire measurement area. The RSm, Rz and Ra values of one area were the average values of the measured values of a total of 15 cross sections obtained by measuring 8 cross sections in the vertical direction and 7 cross sections in the horizontal direction on the measurement screen corresponding to the measurement area. The cutoff value for calculating RSm, Rz and Ra was 0.8 mm.
The measurement device used was a shape analysis laser microscope ("VK-X150 (control unit)/VK-X160 (measurement unit)", manufactured by Keyence Corporation).
<Measurement conditions>
・Objective lens: 50x ・Laser wavelength: 658nm
Measurement mode: Surface shape mode Measurement pitch: 0.13 μm
Measurement quality: High speed mode

1-2. Specular Gloss The 60 degree specular gloss and 85 degree specular gloss of the first surface of the decorative sheets obtained in the Examples and Comparative Examples were measured. Measurements were taken at 10 random locations on each decorative sheet, and the averages of the 10 locations were taken as the 0 degree specular gloss and 85 degree specular gloss of each decorative sheet. A gloss meter ("Microgloss (model name)", manufactured by BYK Gardner) was used as the measuring device.

1-3. Initial antiviral properties The antiviral activity value of the decorative sheets obtained in the Examples and Comparative Examples was measured by the following method. For each decorative sheet, the "predetermined time" described below was gradually increased, and the antiviral activity value was measured every hour and evaluated according to the following criteria. The antiviral activity value was measured against influenza viruses.
<Method for measuring antiviral activity value>
For the decorative sheet and the untreated product, prepare a 5 cm square test piece. Drop 0.4 ml of virus liquid onto the test piece and cover it with a 4 cm square film (in the case of a decorative sheet, drop the virus liquid onto the protective layer side). Leave this test piece for a "predetermined time" in an environment of 25°C and 90% RH. After leaving it, wash out and recover the virus liquid dropped onto the test piece, and measure the virus infectivity. Calculate the antiviral activity value using the following formula (1).
R = Ut - At (1)
R: Antiviral activity value Ut: Average common logarithm of viral infectivity (PFU/cm ² ) of untreated products after standing for 24 hours At: Average common logarithm of viral infectivity (PFU/cm ² ) of decorative sheets after standing for 24 hours <Evaluation criteria>
A: The time required for the antiviral activity value to reach 2.0 was within 10 hours.
B: The time required for the antiviral activity value to reach 2.0 was more than 10 hours and less than 15 hours.
B-: The time required for the antiviral activity value to reach 2.0 was more than 15 hours and less than 20 hours.
C: Time required for the antiviral activity value to reach 2.0 was more than 20 hours.

1-4. Antiviral stability over time (1)
The first surface of the decorative sheets obtained in the Examples and Comparative Examples was abraded under the following conditions (however, those with a rating of "C" in 1-3 were excluded from the evaluation). For the decorative sheets after abrasion, the time until the antiviral activity value reached 2.0 was measured in the same manner as in 1-3. The difference between the time in 1-4 and the time in 1-3 was calculated and evaluated according to the following criteria.
<Evaluation criteria>
A: The difference is within 5 hours.
B: The difference is more than 5 hours and less than 10 hours.
B-: The difference is more than 10 hours and less than 15 hours.
C: The difference is more than 15 hours.
<Wear conditions>
Wear material: Gauze (Kawamoto Sangyo Co., Ltd.)
Wear load: 100g
Wear count: 1000 round trips

1-5. Antiviral stability over time (2)
The first surface of the decorative sheet obtained in the examples was abraded under the following conditions. The antiviral activity value of the abraded decorative sheet was measured in the same manner as in 1-3 (however, the "predetermined time" was fixed at 24 hours). Those having an antiviral activity value of 2.0 or more after 24 hours were rated "A", and those having an antiviral activity value of less than 2.0 after 24 hours were rated "C". The antiviral activity value was measured for influenza virus. Those having an antiviral activity value of 2.0 or more after 24 hours meet the requirements of ISO 21702 and can be said to have good antiviral properties.
<Wear conditions>
Wear material: Gauze (Kawamoto Sangyo Co., Ltd.)
Wear load: 100g
Wear count: 1000 round trips

1-6. Breaking of wiper After the test in 1-4 above, the condition of the gauze was visually evaluated. The gauze was rated as "A" when it was not broken due to the surface unevenness of the decorative sheet, "B" when only a small part of the gauze was broken, and "C" when most of the gauze was broken.

[Example 1]
A corona discharge-treated polypropylene sheet (thickness: 60 μm) was used as the substrate, and a printing ink (binder resin: two-component curing acrylic-urethane resin) was applied by gravure printing to one side of the substrate to provide a decorative layer (thickness: 3 μm) consisting of a colored layer and a pattern layer.
Next, a 3 μm-thick adhesive layer made of a urethane resin adhesive was formed on the decorative layer, and further, a polypropylene resin was hot-melt extruded on the adhesive layer using a T-die extruder to form a transparent resin layer with a thickness of 80 μm. Next, a resin composition containing a two-component curing acrylic-urethane resin was applied on the transparent resin layer to provide a primer layer (thickness: 2 μm).
Next, the following composition 1 for forming a protective layer was applied to the entire surface of the primer layer by a gravure method so that the thickness after drying and curing would be 5 μm.
Next, ultraviolet light was irradiated from the protective layer side using a UV irradiation device composed of LEDs (wavelength: 395 nm, ultraviolet light amount: 6 W/cm ² ), and further ultraviolet light was irradiated using an excimer light irradiation device (wavelength: 172 nm (Xe ₂ ), ultraviolet light output density: 1 W/cm 2 , accumulated light amount: 10 to 100 mJ/cm ² , nitrogen atmosphere (oxygen concentration 200 ppm or less)), and further ultraviolet light was irradiated using a high-pressure mercury lamp (ultraviolet light output density: 200 W/cm 2 ) to form a protective layer.
The above steps produced the decorative sheet of Example 1. The decorative sheet of Example 1 had, from the first surface to the second surface, a protective layer, a primer layer, a transparent resin layer, an adhesive layer, a decorative layer, and a substrate, in this order.

<Composition 1 for forming protective layer>
Multifunctional urethane acrylate oligomer A 30 parts by mass (average number of functional groups: 3, weight average molecular weight: 2400)
50 parts by weight of polyfunctional acrylate monomer A (polyethylene glycol diacrylate, "Light Acrylate 4EG-A" manufactured by Kyoeisha Chemical Co., Ltd.)
・20 parts by mass of polyfunctional acrylate monomer B (glycerin diacrylate, "Aronix M-920" manufactured by Toagosei)
Wrinkle formation stabilizer A 3.0 parts by mass (silica particles, average particle size: 8 μm)
Wrinkle formation stabilizer B 3.0 parts by mass (silica particles, average particle size: 3 μm)
Antiviral agent: 3 parts by mass (antiviral agent containing the following particles A1 and A2 in a mass ratio of 1:1, average particle diameter 5 μm)
(Particle A1: Particles containing a styrene polymer derivative compound, polystyrene sulfonic acid derivative manufactured by Shima Trading Co., Ltd., product name "VERSA-TL3")
(Particles A2: Particles containing an unsaturated carboxylic acid derivative compound, particles formed by drying BYK's solvent-based unsaturated polycarboxylic acid polymer (trade name "BYK-P104"))
Phosphine oxide photopolymerization initiator 0.8 parts by mass (IGM Resin's "Omnirad TPO-L")

[Example 2]
The decorative sheet of Example 2 was obtained in the same manner as in Example 1, except that the polyfunctional urethane acrylate oligomer A contained in the composition 1 for forming the protective layer in Example 1 was changed to a polyfunctional urethane acrylate oligomer B (average number of functional groups: 3, weight average molecular weight: 4400) and the coating amount was changed to 15 μm.

[Example 3]
A decorative sheet of Example 3 was obtained in the same manner as in Example 1, except that the composition 1 for forming a protective layer in Example 1 was changed to the composition 2 for forming a protective layer described below.

<Composition 2 for forming protective layer>
Multifunctional urethane acrylate oligomer B 30 parts by mass (average number of functional groups: 3, weight average molecular weight: 4400)
30 parts by weight of polyfunctional acrylate monomer A (polyethylene glycol diacrylate, "Light Acrylate 4EG-A" manufactured by Kyoeisha Chemical Co., Ltd.)
Polyfunctional acrylate monomer C 20 parts by mass (monomer having a structural unit obtained by ring-opening ε-caprolactone, "KAYARAD HX-220" manufactured by Nippon Kayaku)
・20 parts by mass of polyfunctional acrylate monomer B (glycerin diacrylate, "Aronix M-920" manufactured by Toagosei)
Wrinkle formation stabilizer A 3.0 parts by mass (silica particles, average particle size: 8 μm)
Wrinkle formation stabilizer B 3.0 parts by mass (silica particles, average particle size: 3 μm)
Antiviral agent: 3 parts by mass (antiviral agent containing the particles A1 and the particles A2 in a mass ratio of 1:1, average particle diameter 5 μm)
Phosphine oxide photopolymerization initiator 0.8 parts by mass (IGM Resins'"OmniradTPO-L")

[Example 4]
A decorative sheet of Example 4 was obtained in the same manner as in Example 1, except that the wrinkle formation stabilizer A was changed from silica having an average particle size of 8 μm to alumina having an average particle size of 10 μm.

[Comparative Examples 1 to 3]
In Examples 1 to 3, after the composition for forming the protective layer was applied, the decorative sheets of Comparative Examples 1 to 3 were obtained in the same manner as in Examples 1 to 3, except that the ultraviolet light was not irradiated from a UV irradiation device composed of LEDs and an excimer light irradiation device, but only ultraviolet light was irradiated from a high-pressure mercury lamp.

[Comparative Example 4]
A decorative sheet of Comparative Example 4 was obtained in the same manner as in Example 1, except that the composition 1 for forming a protective layer in Example 1 was changed to the composition 3 for forming a protective layer described below.

<Composition 3 for forming protective layer>
Multifunctional urethane acrylate oligomer C 40 parts by mass (average number of functional groups: 7, weight average molecular weight: 1590)
Acrylic acid 10 parts by mass Polyfunctional acrylate monomer D 15 parts by mass (dipropylene glycol diacrylate, "DPGDA" manufactured by Daicel Allnex)
Polyfunctional acrylate monomer E 10 parts by mass (propylene oxide modified neopentyl glycol diacrylate, Daicel Allnex "EBECRYL 145")
Polyfunctional acrylate monomer F 20 parts by mass (propylene oxide modified tetraglycerin acrylate, BASF "PO9105")
Antiviral agent: 3 parts by mass (antiviral agent containing the particles A1 and the particles A2 in a mass ratio of 1:1, average particle diameter 5 μm)
Phosphine oxide photopolymerization initiator 0.8 parts by mass (IGM Resins'"OmniradTPO-L")

[Comparative Example 5]
A decorative sheet of Comparative Example 5 was obtained in the same manner as in Example 1, except that the composition 1 for forming a protective layer in Example 1 was changed to the composition 4 for forming a protective layer described below.

<Composition 4 for forming protective layer>
Multifunctional urethane acrylate oligomer D 40 parts by mass (average number of functional groups: 6, weight average molecular weight: 855)
・25 parts by mass of polyfunctional acrylate monomer E (propylene oxide modified neopentyl glycol diacrylate, Daicel Allnex "EBECRYL 145")
35 parts by mass of polyfunctional acrylate monomer G (hexanediol diacrylate, "Viscoat #230" manufactured by Osaka Organic Chemical Industry Co., Ltd.)
Antiviral agent: 3 parts by mass (antiviral agent containing the particles A1 and the particles A2 in a mass ratio of 1:1, average particle diameter 5 μm)
Phosphine oxide photopolymerization initiator 0.8 parts by mass (IGM Resins'"OmniradTPO-L")

[Comparative Example 6]
A decorative sheet of Comparative Example 6 was obtained in the same manner as in Example 1, except that the polyfunctional acrylate monomers A and B in Example 1 were changed to the following polyfunctional acrylate monomers G and H.
Polyfunctional acrylate monomer G 35 parts Polyfunctional acrylate monomer H 25 parts
(Polyethylene glycol diacrylate, Kyoeisha Chemical's "Light Acrylate 3EG-A")

[Comparative Example 7]
A decorative sheet of Comparative Example 7 was obtained in the same manner as in Example 1, except that the multifunctional urethane acrylate oligomer A, the multifunctional acrylate monomer A, and the multifunctional acrylate monomer B in Example 1 were changed to the following multifunctional acrylate oligomer B, the multifunctional acrylate monomers E and G.
Polyfunctional urethane acrylate oligomer B 40 parts Polyfunctional acrylic monomer E 25 parts Polyfunctional acrylic monomer G 35 parts

The results in Table 1 confirm that the decorative sheet of the present disclosure can efficiently exhibit antiviral properties and inhibit the deterioration of antiviral properties over time.

1: Decorative sheet 2: Concave portion 3: Convex portion (protrusion portion)
4: Protective layer 5: Base material 6: Decorative layer 6a: Colored layer 6b: Design layer 7: Adhesive layer 8: Transparent resin layer 9: Primer layer

Claims

A decorative sheet having a first surface and a second surface opposite to the first surface,
The decorative sheet has, from the first surface to the second surface, a protective layer, a decorative layer, and a base material in this order,
the protective layer comprises a binder resin and an antiviral agent,
The first surface of the decorative sheet satisfies the following conditions 1 and 2.
<Condition 1>
The developed area ratio Sdr of the interface according to ISO 25178-2:2012 is 0.500 or more.
<Condition 2>
When the ratio of Rz, which is the maximum height in JIS B0601:2013, to RSm, which is the average length of the roughness curve element in JIS B0601:2013, is defined as RSm/Rz, RSm/Rz is 5.5 or less.
The decorative sheet according to claim 1, wherein, in condition 1, Sdr is 0.500 or more and 1.500 or less.
The decorative sheet according to claim 1, wherein RSm/Rz is 3.0 or more and 5.5 or less under condition 2.
The decorative sheet according to claim 1, wherein the first surface has a maximum height Rz according to JIS B0601:2013 of 4.5 μm or more and 8.5 μm or less.
The decorative sheet according to claim 1, wherein the first surface has a roughness curve element average length RSm according to JIS B0601:2013 of 20.0 μm or more and 50.0 μm or less.
The decorative sheet according to claim 1, wherein the first surface has an arithmetic mean roughness Ra according to JIS B0601:2013 of 0.6 μm or more and 1.5 μm or less.
The decorative sheet according to claim 1, having a protective layer on the entire surface of the decorative sheet when viewed in plan.
The decorative sheet according to claim 1, comprising 0.5 parts by mass or more and 20.0 parts by mass or less of the antiviral agent per 100 parts by mass of the binder resin.
The decorative sheet according to claim 1, wherein the binder resin comprises a cured product of a resin composition containing a curable resin.
The decorative sheet according to claim 1, wherein the layer located on the outermost surface of the first surface side is the protective layer.
The decorative sheet according to claim 1, wherein the 60-degree specular gloss of the first surface according to JIS Z8741:1997 is 1.0 or more and 20.0 or less, and the 85-degree specular gloss of the first surface according to JIS Z8741:1997 is 7.0 or more and 25.0 or less.
The decorative sheet according to claim 1, having a total light transmittance according to JIS K7361-1:1997 of 20% or less.