JP7800126B2 - Laminated Sheet - Google Patents

Description

This disclosure relates to a laminated sheet.

In recent years, there have been outbreaks of pandemic viruses, such as the novel coronavirus (COVID-19) and avian influenza. As a countermeasure, progress has been made in the development of materials that can inactivate viruses. Furthermore, building materials used in everyday living spaces are also being required to have the same virus inactivation properties.

For example, Patent Document 1 discloses an antiviral vinyl chloride resin wallpaper comprising a polyvinyl chloride resin layer containing a polyvinyl chloride resin formed by mixing a paste vinyl chloride resin and a suspension vinyl chloride resin, and a sulfonic acid surfactant. Patent Document 2 also discloses an antiviral wallpaper having a substrate, a resin layer, and a surface treatment layer, in that order, in which the surface treatment layer contains a resin for the surface treatment layer and a photocatalyst.

Patent Document 3 discloses a decorative sheet having a colored thermoplastic resin layer, a design layer, a transparent thermoplastic resin layer, and a surface protective layer, at least in this order. It further discloses that the surface protective layer contains an antiviral additive in which the active ingredient is supported on an inorganic material. Patent Document 4 discloses a decorative sheet having a surface protective layer provided on a base sheet. It further discloses that the surface protective layer contains an antiviral agent containing a quaternary ammonium salt as an active ingredient.

Patent No. 6182386 Patent No. 6137716 Patent No. 6892031 Patent No. 6888726

As mentioned above, Patent Documents 3 and 4 disclose the addition of an antiviral agent to the surface protective layer. By adding an antiviral agent to the surface protective layer, for example, if a virus adheres to the surface protective layer, the virus is effectively inactivated.

Patent Document 4 discloses an antiviral agent containing a quaternary ammonium salt. However, antiviral agents containing quaternary ammonium salts have low heat resistance. Therefore, for example, when a heat treatment is performed during the production of a laminated sheet, the antiviral agent may decompose, and discoloration due to this decomposition may occur.

The present disclosure was made in consideration of the above-mentioned circumstances, and aims to provide a laminate sheet having a surface protective layer that combines antiviral properties and heat resistance.

The present disclosure provides a laminate sheet for use in building materials, the laminate sheet having a base layer and a surface protective layer, the surface protective layer containing a resin component, a cationic polymer-based antiviral agent A, and a silver-based or silver-zinc-based antiviral agent B.

The present disclosure has the effect of providing a laminate sheet having a surface protective layer that is both antiviral and heat resistant.

1 is a schematic cross-sectional view illustrating a laminate sheet according to the present disclosure. 1 is a schematic cross-sectional view illustrating a laminate sheet according to the present disclosure. 1 is a schematic cross-sectional view illustrating a laminate sheet according to the present disclosure.

Embodiments are described below with reference to the drawings. However, this disclosure can be implemented in many different forms and should not be limited to the description of the embodiments exemplified below. Furthermore, to clarify the explanation, the drawings may show the width, thickness, and shape of each part more schematically than the actual form, but this is merely an example and should not be interpreted as limiting.

In this specification, when describing the arrangement of another component on a certain component, the terms "above" or "below" are used, unless otherwise specified, to include both the case where another component is placed directly above or below the component so as to be in contact with the component, and the case where another component is placed above or below the component with another component interposed between them. Furthermore, in this specification, when describing the arrangement of another component on the surface of a certain component, the term "on the surface" is used, unless otherwise specified, to include both the case where another component is placed directly above or below the component so as to be in contact with the component, and the case where another component is placed above or below the component with another component interposed between them.

The laminate sheet of the present disclosure will be described in detail below. Figure 1 is a schematic cross-sectional view illustrating an example of a laminate sheet of the present disclosure. The laminate sheet 10 shown in Figure 1 has a substrate layer 1 and a surface protective layer 2. The surface protective layer 2 contains a resin component, a cationic polymer-based antiviral agent A, and a silver-based or silver-zinc-based antiviral agent B.

Figure 2 is a schematic cross-sectional view illustrating a laminate sheet according to the present disclosure, showing a layer structure suitable for, for example, a wall decorative sheet (wallpaper). The laminate sheet 10 shown in Figure 2 has, in the thickness direction _DT , a substrate layer 1, a foamed resin layer 3, a decorative layer 4, a film layer 5, and a surface protective layer 2, in this order. Figure 3 is a schematic cross-sectional view illustrating a laminate sheet according to the present disclosure, showing a layer structure suitable for, for example, a floor decorative sheet. The laminate sheet 10 shown in Figure 3 has, in the thickness direction _DT , a substrate layer 1, a decorative layer 4, a film layer 5, a primer layer 6, and a surface protective layer 2, in this order.

According to the present disclosure, by using antiviral agent A and antiviral agent B, a laminate sheet is obtained having a surface protective layer that combines antiviral properties and heat resistance. As mentioned above, Patent Document 4 discloses an antiviral agent containing a quaternary ammonium salt. However, antiviral agents containing quaternary ammonium salts have low heat resistance. Therefore, for example, if a heat treatment is performed during the production of a laminate sheet, the antiviral agent may decompose, and discoloration due to this decomposition may occur. In particular, in the case of decorative wall sheets and decorative floor sheets described below, which are often subjected to heat treatment during production, a surface protective layer that is less susceptible to deterioration due to heat treatment is required.

In contrast, the present disclosure uses a cationic polymer-based antiviral agent A. Cationic polymer-based antiviral agents have cationic functional groups, such as quaternary ammonium bases, incorporated into the polymer structure, making them highly heat-resistant. Therefore, even if heat treatment is performed during the production of the laminate sheet, for example, decomposition of the antiviral agent can be suppressed.

Furthermore, for example, when a cationic polymer-based antiviral agent A is used and discoloration due to decomposition of the antiviral agent A is sufficiently suppressed, the amount of antiviral agent A used is limited, and a surface protective layer with good antiviral properties may not be obtained. In contrast, for example, when a cationic polymer-based antiviral agent A is used and good antiviral properties are desired, the amount of antiviral agent A used is large, and a surface protective layer in which discoloration due to decomposition of the antiviral agent A is not sufficiently suppressed may not be obtained. Thus, when a cationic polymer-based antiviral agent A is used, although heat resistance can be improved compared to conventional antiviral agents containing quaternary ammonium salts (antiviral agents that are not polymer-based), it is difficult to obtain a laminate sheet having a surface protective layer that combines antiviral properties and heat resistance.

In the present disclosure, in addition to a cationic polymer-based antiviral agent A, a silver-based or silver-zinc-based antiviral agent B is used. Because antiviral agent B is an inorganic antiviral agent, it has even higher heat resistance than antiviral agent A. By using antiviral agents A and B in combination, better antiviral properties can be obtained while limiting the amount of antiviral agent A used (i.e., while suppressing discoloration due to decomposition of antiviral agent A) compared to using antiviral agent A alone. In this way, using antiviral agents A and B results in a laminate sheet having a surface protective layer that combines antiviral properties and heat resistance.

Furthermore, while silver- or silver-zinc-based antiviral agents B have higher light resistance (less susceptible to discoloration due to light) than, for example, copper- or silver-copper-based antiviral agents, they have lower light resistance than cationic polymer-based antiviral agents A. For example, when antiviral agent B is used and attempts are made to sufficiently suppress discoloration due to light, the amount of antiviral agent B used is limited, and a surface protective layer with good antiviral properties may not be obtained. In contrast, when antiviral agent B is used and attempts are made to achieve good antiviral properties, the amount of antiviral agent B used is large, and a surface protective layer that sufficiently suppresses discoloration due to light may not be obtained. As such, focusing on antiviral agent B makes it difficult to obtain a laminate sheet with a surface protective layer that combines antiviral properties and light resistance. In the present disclosure, by using antiviral agents A and B in combination, good antiviral properties can be obtained while limiting the amount of antiviral agent B used (i.e., suppressing discoloration due to light) compared to using antiviral agent B alone. Based on these considerations, by using antiviral agent A and antiviral agent B in combination, it is possible to achieve both antiviral properties and light resistance, as well as both antiviral properties and heat resistance, i.e., it is possible to achieve both antiviral properties, heat resistance, and light resistance.

1. Surface Protective Layer The surface protective layer in the present disclosure contains a resin component, a cationic polymer-based antiviral agent A, and a silver-based or silver-zinc-based antiviral agent B. Furthermore, as shown in FIG. 1 , laminate sheet 10 may have surface protective layer 2 as the outermost layer.

(1) Antiviral agent A
The antiviral agent A in the present disclosure is a cationic polymer-based antiviral agent. The surface protective layer may contain only one type of antiviral agent A, or may contain two or more types. The cationic polymer refers to a polymer having a cationic functional group. Examples of the cationic functional group include a quaternary ammonium base and a quaternary phosphonium base. The cationic polymer usually has a cationic functional group in at least one of the main chain and the side chain. The cationic polymer may have a cationic functional group in the main chain but not in the side chain. Alternatively, the cationic polymer may have a cationic functional group in the side chain but not in the main chain. Alternatively, the cationic polymer may have a cationic functional group in the main chain and not in the side chain.

It is preferable that antiviral agent A has a quaternary ammonium base as the cationic functional group. This is because it has excellent antiviral properties. When antiviral agent A has a quaternary ammonium base in its main chain, it may have a structural unit represented by the following (1):

In the above (1), R ¹ to R ⁴ are each independently a functional group containing at least carbon. The number of carbon atoms in ^{R 1} and R ² is, for example, 1 to 10, or optionally 1 to 5. ^{R 1} and R ² are each, for example, an alkylene group. At least one of R ¹ and R ² may have a quaternary ammonium base. The number of carbon atoms in ^{R 3} and R ⁴ is, for example, 1 to 10, or optionally 1 to 5. R ³ and R ⁴ are, for example, a hydrocarbon group. The hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. Furthermore, hydrogen (H) in the hydrocarbon group may be substituted with another element or a functional group. The antiviral agent A preferably has the structural unit represented by the above (1) as the main component of its main chain. This is because the heat resistance of the antiviral agent A is improved.

Antiviral agent A may have a structural unit represented by the following (2):

In the above (2), R ¹¹ is an alkyl group or hydroxyalkyl group having 1 to 4 carbon atoms, or an alkenyl group having 2 to 4 carbon atoms, and the four R ¹¹ may be the same or different. R ¹² is an alkylene group having 2 to 10 carbon atoms. R ¹³ is a heteroalkylene group having 2 to 6 carbon atoms, or a heteroalkylene group having a hydroxyl group. ^{A −} is an anion.

Examples of alkyl groups having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, isopropyl, and n-butyl. Examples of hydroxyalkyl groups having 1 to 4 carbon atoms include hydroxymethyl, hydroxyethyl, hydroxypropyl, 1-methyl-1-hydroxyethyl, and 1-methyl-2-hydroxyethyl. Examples of alkenyl groups having 2 to 4 carbon atoms include vinyl and allyl. The alkylene group having 2 to 10 carbon atoms may be a linear alkylene group or a branched alkylene group. Examples of alkylene groups include ethylene, propylene, trimethylene, tetramethylene, hexamethylene, 2-ethylhexamethylene, octamethylene, and decamethylene. A heteroalkylene group having 2 to 6 carbon atoms or a heteroalkylene group having a hydroxyl group preferably has at least one of oxygen and sulfur as a heteroatom. Examples of such heteroalkylene groups include a methyleneoxymethylene group, a methyleneoxyethylene group, an ethyleneoxyethylene group, an ethyleneoxymethyleneoxyethylene group, a methylenethiomethylene group, a methylenethioethylene group, and an ethylenethioethylene group. Examples of heteroalkylene groups having a hydroxyl group include a 1-hydroxy-3-oxapentylene group and a 1,4-dihydroxy-2-oxabutylene group. Examples of the anion represented by ^A- include anions derived from mono- or polycarboxylic acids such as formic acid, acetic acid, propionic acid, gluconic acid, lactic acid, fumaric acid, maleic acid, adipic acid, and tartaric acid, acidic phosphate ester anions, alkyl sulfate ester anions, halogen anions, phosphate anions, sulfate anions, and nitrate anions. It is preferable that the antiviral agent A has the structural unit represented by (2) above as the main component of its main chain.

When antiviral agent A has a quaternary ammonium base in a side chain, antiviral agent A may have a structural unit having a side chain represented by the following (3):

In the above (3), R ³¹ to R ³⁴ are each independently a functional group containing at least carbon. The number of carbon atoms in R ³¹ is, for example, 1 or more and 10 or less, and may be 1 or more and 5 or less. R ³¹ is, for example, an alkylene group. The number of carbon atoms in R ³² to R ³⁴ is, for example, 1 or more and 10 or less, and may be 1 or more and 5 or less. R ³² to R ³⁴ are, for example, a hydrocarbon group. The hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. Furthermore, hydrogen (H) in the hydrocarbon group may be substituted with another element or a functional group.

The antiviral agent A may be a cationic olefin resin. The cationic olefin resin has an olefin such as ethylene or propylene in its structural skeleton. The antiviral agent A may also be a cationic urethane resin or a cationic amine resin. The antiviral agent A may also have a synthetic polymer such as an olefin in its structural skeleton, or may have a natural polymer such as chitin or chitosan in its skeletal structure. The antiviral agent A may also be water-soluble. The antiviral agent A may also be in an emulsion state.

The weight-average molecular weight (Mw) of antiviral agent A is not particularly limited, but is, for example, 10,000 or more, and may be 30,000 or more. If the weight-average molecular weight is too small, antiviral agent A may not exhibit good heat resistance. On the other hand, the weight-average molecular weight (Mw) of antiviral agent A may be, for example, 1,000,000 or less, and may be 800,000 or less. If the weight-average molecular weight is too large, antiviral agent A may not exhibit good antiviral properties. The weight-average molecular weight in this disclosure can be determined as a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

Specific examples of antiviral agent A include Amorden D-CL50 (manufactured by Yamato Chemical Industry Co., Ltd.), Biocide Neo (manufactured by Taisho Technos Co., Ltd.), Nikkanon RB (manufactured by Nicca Chemical Co., Ltd.), FC-V20S (manufactured by Fuji Chemical Industry Co., Ltd.), Marukaside CP (manufactured by Osaka Kasei Co., Ltd.), and Arrowbase (manufactured by Unitika Co., Ltd.).

The content of antiviral agent A is, for example, 0.1 parts by mass or more, or may be 0.5 parts by mass or more, 1 part by mass or more, 3 parts by mass or more, or 5 parts by mass or more, per 100 parts by mass of the resin component. If the content of antiviral agent A is too low, good antiviral properties may not be exhibited. On the other hand, the content of antiviral agent A may be, for example, 15 parts by mass or less, or may be 12 parts by mass or less, per 100 parts by mass of the resin component. If the content of antiviral agent A is too high, the contamination resistance of the surface protective layer may be reduced.

The total content of antiviral agent A and antiviral agent B is, for example, 1 part by mass or more, or may be 3 parts by mass or more, 5 parts by mass or more, or 7 parts by mass or more, per 100 parts by mass of the resin component. If the total content of antiviral agent A and antiviral agent B is too low, good antiviral properties may not be exhibited. On the other hand, the total content of antiviral agent A and antiviral agent B may be, for example, 20 parts by mass or less, or may be 15 parts by mass or less, per 100 parts by mass of the resin component. If the total content of antiviral agent A and antiviral agent B is too high, the contamination resistance of the surface protective layer may be reduced.

The mass ratio (A/B) of antiviral agent A to antiviral agent B is, for example, 0.05 or more, and may be 0.1 or more, or even 0.5 or more. On the other hand, the mass ratio (A/B) is, for example, 10 or less, and may be 5 or less.

(2) Antiviral agent B
The antiviral agent B in the present disclosure is a silver-based or silver-zinc-based antiviral agent. The surface protective layer may contain only one type of antiviral agent B, or may contain two or more types. For example, the surface protective layer may contain a silver-based antiviral agent and a silver-zinc-based antiviral agent. Furthermore, a silver-based antiviral agent is typically an antiviral agent having only silver as the active ingredient. On the other hand, a silver-zinc-based antiviral agent is typically an antiviral agent having at least silver and zinc as active ingredients, and may be an antiviral agent having only silver and zinc as active ingredients. The antiviral agent B typically has a carrier and metal ions (silver ions, zinc ions) supported on or contained in the carrier.

The carrier for antiviral agent B may be an inorganic material or an organic material. Examples of inorganic materials include glass, apatite, zeolite, zirconium phosphate, and titanium phosphate. Discoloration can be particularly suppressed when glass or apatite is used. Examples of glass include soda glass, borosilicate glass, lead glass, aluminosilicate glass, borate glass, and phosphate glass.

Apatite is a general term for minerals having a composition represented by the following general formula:
M ₁₀ (ZO ₄ ) ₃ X ₂
In the above formula, M is at least one of Ca, Ba, Mg, Na, K, Fe, and Al, Z is at least one of P, S, Si, and As, and X is at least one of F, Cl, O, and OH. Specific examples of apatite include fluorapatite ( _Ca10 ( _PO4 ) _6F2 ) and hydroxyapatite ( _Ca10 ( _PO4 ) ₆ (OH) _{2 )} .

Examples of organic materials include resins. Examples of resins include copolymers of styrenes or α-olefins with (meth)acrylic acid, and polyacetal resins.

Antiviral agent B typically comprises a carrier and an active ingredient (metal ion) supported on or contained in the carrier. Here, "the active ingredient is contained in the carrier" means that the active ingredient or a substance capable of generating the active ingredient is held within the carrier. Furthermore, "a substance capable of generating an active ingredient" refers to a substance that generates an active ingredient due to external factors or factors over time, such as a substance that generates an active ingredient upon dissolving in water. Examples of substances capable of generating an active ingredient include elemental metals, metal alloys, inorganic salts, oxides, and hydroxides.

The active ingredient or a substance capable of generating an active ingredient (hereinafter referred to as the active ingredient, etc.) may be supported on or contained in a carrier by physical or chemical adsorption. The active ingredient may also be supported on or contained in a carrier by an ion exchange reaction. The substance capable of generating an active ingredient may also be supported on or contained in a carrier by a binder.

The amount of the active ingredient in antiviral agent B is, for example, 0.1 parts by mass or more and 30 parts by mass or less, or alternatively 0.5 parts by mass or more and 25 parts by mass or less, or 1 part by mass or more and 20 parts by mass or less, per 100 parts by mass of carrier.

Preferably, the antiviral agent B is, for example, in the form of particles. Examples of the particle shape of the antiviral agent B include spheres, ellipsoids, polyhedrons, and scales. The average particle diameter of the antiviral agent B is, for example, 0.5 μm or more and 10 μm or less, and may be 1.0 μm or more and 5.0 μm or less. The average particle diameter in the present disclosure is the cumulative 50% value (D ₅₀ , median diameter) in particle size distribution measurement by laser light diffraction method.

The average particle diameter of the antiviral agent B is D _B , and the thickness of the surface protective layer is T. _{D B} /T may be 1 or less, or may be greater than 1. When _{D B} /T is 1 or less, it is possible to prevent the antiviral agent B from protruding from the surface of the surface protective layer. D _B /T may be 0.8 or less, or may be 0.6 or less. On the other hand, D _B /T is, for example, 0.1 or more.

Specific examples of antiviral agent B include Novalon IV-1000 (manufactured by Toagosei), Amteclean Z (manufactured by Amtec), and Zeomic (manufactured by Sinanen Zeomic).

The content of antiviral agent B is, for example, 0.1 parts by mass or more, or may be 0.5 parts by mass or more, 1 part by mass or more, 3 parts by mass or more, or 5 parts by mass or more, per 100 parts by mass of the resin component. If the content of antiviral agent B is too low, good antiviral properties may not be exhibited. On the other hand, the content of antiviral agent B may be, for example, 15 parts by mass or less, or may be 12 parts by mass or less, per 100 parts by mass of the resin component. If the content of antiviral agent B is too high, the contamination resistance of the surface protective layer may be reduced.

(3) Resin Component The surface protective layer contains a resin component. The resin component mainly functions as a binder resin. The surface protective layer preferably contains, as the resin component, at least one of a resin composition and a cured product thereof. The cured product may be a cured product obtained by curing a curable resin composition with ionizing radiation, or a cured product obtained by curing a curable resin composition with heat.

Examples of curable resin compositions include ionizing radiation-curable resin compositions and thermosetting resin compositions. From the standpoints of scratch resistance and production efficiency, ionizing radiation-curable resin compositions are preferred. That is, the surface protection layer preferably contains a cured product of an ionizing radiation-curable resin composition as the resin component.

Specific examples of the ionizing radiation curable resin composition include an electron beam curable resin composition and an ultraviolet ray curable resin composition. Among these, an electron beam curable resin composition has advantages such as less odor and less discoloration because it does not require a polymerization initiator.

An ionizing radiation-curable resin composition is a composition containing a compound having an ionizing radiation-curable functional group (hereinafter also referred to as an "ionizing radiation-curable compound"). The ionizing radiation-curable functional group is a group that crosslinks and cures upon exposure to ionizing radiation. Specific examples include functional groups having an ethylenic double bond, such as a (meth)acryloyl group, a vinyl group, or an allyl group. Other specific examples of ionizing radiation-curable functional groups include an epoxy group and an oxetanyl group. In this specification, a (meth)acryloyl group refers to an acryloyl group or a methcroyl group. In this specification, a (meth)acrylate refers to an acrylate or a methacrylate. Ionizing radiation refers to electromagnetic waves or charged particle beams that have an energy quantum capable of polymerizing or crosslinking molecules. Specific examples of ionizing radiation include ultraviolet (UV) radiation and electron beams (EB). Other specific examples of ionizing radiation include electromagnetic waves such as X-rays and gamma rays, and charged particle beams such as alpha rays and ion beams.

The ionizing radiation-curable resin composition may contain only one type of ionizing radiation-curable compound, or may contain two or more types. There are no particular restrictions on the type of ionizing radiation-curable compound, and known polymerizable monomers and known polymerizable oligomers (polymerizable prepolymers) can be used.

The ionizing radiation-curable compound preferably contains a compound having two or more ethylenically unsaturated bond groups. In particular, the ionizing radiation-curable compound preferably contains a polyfunctional (meth)acrylate compound having two or more ethylenically unsaturated bond groups. The polyfunctional (meth)acrylate compound may be a monomer or an oligomer.

The polyfunctional (meth)acrylate compound may be a difunctional (meth)acrylate monomer or a trifunctional or higher functional (meth)acrylate monomer. Examples of difunctional (meth)acrylate monomers include ethylene glycol di(meth)acrylate, bisphenol A tetraethoxydiacrylate, bisphenol A tetrapropoxydiacrylate, and 1,6-hexanediol diacrylate. Examples of trifunctional or higher functional (meth)acrylate monomers include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and isocyanuric acid-modified tri(meth)acrylate.

Examples of polyfunctional (meth)acrylate oligomers include acrylate polymers such as urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and polyether (meth)acrylate.

Urethane (meth)acrylates can be obtained, for example, by reacting a polyhydric alcohol and an organic diisocyanate with a hydroxy (meth)acrylate. Epoxy (meth)acrylates can be obtained, for example, by reacting an epoxy resin with (meth)acrylic acid. During this reaction, at least one of a polybasic acid and a phenol may also be used. Epoxy resins may be bifunctional, trifunctional, or higher. Examples of epoxy resins include aromatic epoxy resins, alicyclic epoxy resins, and aliphatic epoxy resins.

The ionizing radiation curable compound may contain silicone (meth)acrylate. The use of silicone (meth)acrylate improves the contamination resistance of the surface protective layer. Examples of silicone (meth)acrylate include silicone oil containing polysiloxane. The silicone (meth)acrylate may be a modified silicone oil in which a (meth)acrylic group is introduced at the end of polysiloxane. The content of silicone (meth)acrylate is, for example, 1 part by mass or more and 7 parts by mass or less, or may be 2 parts by mass or more and 5 parts by mass or less, per 100 parts by mass of the ionizing radiation curable compound (excluding silicone (meth)acrylate).

When the ionizing radiation-curable compound is an ultraviolet-curable compound, the ionizing radiation-curable resin composition preferably contains additives such as a photopolymerization initiator and a photopolymerization accelerator. Examples of photopolymerization initiators include acetophenone, benzophenone, α-hydroxyalkylphenone, Michler's ketone, benzoin, benzil dimethyl ketal, benzoyl benzoate, α-acyloxime ester, and thioxanthone. Examples of photopolymerization accelerators include p-dimethylaminobenzoic acid isoamyl ester and p-dimethylaminobenzoic acid ethyl ester.

On the other hand, a thermosetting resin composition is a composition that contains at least a thermosetting resin. This resin composition cures when heated. Examples of thermosetting resins include acrylic resins, urethane resins, phenolic resins, urea melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins. Thermosetting resin compositions may contain additives such as curing agents and curing catalysts, as needed.

(4) Additives The surface protective layer may further contain at least one of an antioxidant, a light stabilizer, and an ultraviolet absorber as an additive. Examples of antioxidants include phenol-based antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants. Among these, phosphorus-based antioxidants can effectively suppress discoloration of the surface protective layer due to light. Examples of light stabilizers include hindered amine compounds. Hindered amine compounds typically have a structure containing a 2,2,6,6-tetramethylpiperidine skeleton in the molecule. Examples of hindered amine compounds include NH-type hindered amine compounds, NR-type hindered amine compounds, and NOR-type hindered amine compounds. Examples of ultraviolet absorbers include benzotriazole-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, and triazine-based ultraviolet absorbers.

(5) Surface Protective Layer The surface protective layer in the present disclosure contains at least a resin component, a cationic polymer-based antiviral agent A, and a silver-based or silver-zinc-based antiviral agent B. The thickness of the surface protective layer is not particularly limited, but may be, for example, 1.0 μm or more and 20 μm or less, or may be 1.5 μm or more and 15 μm or less, or may be 2.0 μm or more and 10 μm or less.

One method for forming the surface protective layer is to apply a mixture containing a resin component, a cationic polymer-based antiviral agent A, and a silver-based or silver-zinc-based antiviral agent B to the surface of the base layer, dry it, and harden it. Alternatively, the mixture may be applied to the surface of a substrate having releasability, dried, and hardened to form a surface protective layer, which may then be transferred onto the base layer.

2. Substrate Layer The substrate layer in the present disclosure is a layer that supports the surface protective layer. Examples of constituent materials of the substrate layer include fibrous materials, resins, metals, and non-metallic inorganic materials. The substrate layer may be a single layer or a laminate of two or more layers. In the latter case, the substrate layer may have two or more layers made of the same type of constituent material, or two or more layers made of different types of constituent material.

Fiber materials used in the base layer include, for example, tissue paper, kraft paper, fine paper, Japanese paper, titanium paper, linter paper, parchment paper, paraffin paper, parchment paper, glassine paper, wallpaper backing paper, paperboard, and plasterboard base paper. The above-mentioned paper may be general paper or flame-retardant paper. Flame-retardant paper is general paper containing a flame retardant. Examples of flame retardants include nitrogen compounds such as urea and ammonium compounds, hydroxides (preferably hydrates) such as magnesium hydroxide and aluminum hydroxide, and self-extinguishing flame retardants containing phosphorus or halogen elements. In particular, compounds containing water of crystallization, such as magnesium hydroxide, can be flame-retarded by the heat of vaporization of the water of crystallization during combustion and decomposition.

Other examples of fibrous materials include woven fabrics and nonwoven fabrics. Fibers used in woven fabrics or nonwoven fabrics include, for example, resin fibers (e.g., polyester resin fibers, acrylic resin fibers), natural fibers (e.g., silk, cotton, linen), glass fibers, and carbon fibers. Furthermore, when a fibrous material is used for the base layer, resins such as acrylic resins, styrene butadiene rubber, melamine resins, and urethane resins may be added (by impregnation with resin after papermaking, or by filling with resin during papermaking). Furthermore, the base layer may be wallpaper roll, in which a resin layer such as a vinyl chloride resin layer, an olefin resin layer, or an acrylic resin layer is laminated on the surface of wallpaper backing paper.

Resins used in the base layer include, for example, synthetic resins and natural resins. Examples of synthetic resins include thermoplastic resins. Examples of thermoplastic resins include olefin-based resins such as polyethylene, polypropylene, polymethylpentene, ionomers, and olefin-based thermoplastic elastomers; vinyl chloride-based resins such as polyvinyl chloride, polyvinylidene chloride, and vinyl chloride-vinyl acetate copolymers; polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, ethylene glycol-terephthalic acid-isophthalic acid copolymers, and polyester-based thermoplastic elastomers; acrylic resins such as polymethyl (meth)acrylate, polyethyl (meth)acrylate, polybutyl (meth)acrylate, and methyl (meth)acrylate-butyl (meth)acrylate copolymers; polyamide-based resins such as nylon 6 and nylon 66; cellulose-based resins such as cellulose triacetate, cellophane, and celluloid; and styrene-based resins such as polystyrene, acrylonitrile-styrene copolymers, and acrylonitrile-butadiene-styrene copolymers (ABD). Other examples of thermoplastic resins include polyvinyl alcohol, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polycarbonate resin, polyarylate resin, and polyimide resin. Examples of natural resins include natural rubber, pine resin, and amber.

Examples of metals used for the substrate layer include aluminum, aluminum alloys (e.g., duralumin), iron, iron alloys (e.g., carbon steel, stainless steel), copper, copper alloys (e.g., brass, bronze), gold, silver, chromium, nickel, cobalt, tin, and titanium. The metal surface may also be plated.

Non-metallic inorganic materials used in the base layer include, for example, non-ceramic ceramic materials such as cement, ALC (lightweight aerated concrete), gypsum, calcium silicate, and wood chip cement; ceramic ceramic materials such as porcelain, earthenware, glass, and enamel; and natural stones such as limestone (including marble), granite, and andesite.

The substrate layer may contain additives such as flame retardants, inorganic agents, dry strength agents, wet strength agents, colorants, sizing agents, and fixing agents, as needed. The substrate layer may also be surface-treated, for example, to improve adhesion. Examples of surface treatments include oxidation and roughening. Examples of oxidation methods include corona discharge treatment, chromium oxidation treatment, flame treatment, hot air treatment, and ozone-ultraviolet treatment. Examples of roughening methods include sandblasting and solvent treatment.

The substrate layer may be, for example, in the form of a sheet. The thickness of the substrate layer is not particularly limited, but may be, for example, 10 μm or more and 300 μm or less. The basis weight of the substrate layer is not particularly limited, but may be, for example, 50 g/m ² or more and 300 g/m ² or less, and may be, for example, 60 g/m ² or more and 160 g/m ² or less.

3. Laminate Sheet The laminate sheet of the present disclosure has at least a substrate layer and a surface protective layer. The laminate sheet may have only the substrate layer and the surface protective layer, or may have other layers in addition to the substrate layer and the surface protective layer. Examples of other layers include a foamed resin layer, a non-foamed resin layer, a decorative layer, a primer layer, a film layer, and an adhesive layer.

Examples of the layer structure of the laminated sheet include the layer structures shown below.
(1) Substrate layer / foamed resin layer / surface protective layer (2) Substrate layer / foamed resin layer / primer layer / surface protective layer (3) Substrate layer / foamed resin layer / decorative layer / surface protective layer (4) Substrate layer / foamed resin layer / decorative layer / primer layer / surface protective layer (5) Substrate layer / foamed resin layer / adhesive layer / film layer / surface protective layer (6) Substrate layer / foamed resin layer / adhesive layer / decorative layer / film layer / surface protective layer (7) Substrate layer / foamed resin layer / decorative layer / adhesive layer / film layer / surface protective layer (8) Substrate layer / foamed resin layer / film layer / primer layer / surface protective layer (9) Substrate layer / foamed resin layer / adhesive layer / film layer / primer layer / surface protective layer (10) Substrate layer / foamed resin layer / adhesive layer / decorative layer / film layer / primer layer / surface protective layer (11) Substrate layer / foamed resin layer/decorative layer/adhesive layer/film layer/primer layer/surface protective layer (12) substrate layer/surface protective layer (13) substrate layer/primer layer/surface protective layer (14) substrate layer/decorative layer/surface protective layer (15) substrate layer/decorative layer/primer layer/surface protective layer (16) substrate layer/adhesive layer/film layer/surface protective layer (17) substrate layer/adhesive layer/decorative layer/film layer/surface protective layer (18) substrate layer/decorative layer/adhesive layer/film layer/surface protective layer (19) substrate layer/film layer/primer layer/surface protective layer (20) substrate layer/adhesive layer/film layer/primer layer/surface protective layer (21) substrate layer/adhesive layer/decorative layer/film layer/primer layer/surface protective layer (22) substrate layer/decorative layer/adhesive layer/film layer/primer layer/surface protective layer

The "/" above indicates the relative positional relationship of each layer; for example, "A/B/C" means that A, B, and C are arranged in that order along the thickness direction. Furthermore, for example, when written as "A/B," A and B may be arranged so that they are in direct contact with each other, or may be arranged via another layer. Furthermore, as exemplified in (1) to (11) above, when the laminate sheet has a foamed resin layer, a non-foamed resin layer may be arranged on one or both sides of the foamed resin layer.

(1) Foamed Resin Layer The laminate sheet may have a foamed resin layer between the substrate layer and the surface protective layer. Providing a foamed resin layer improves the design and texture of the laminate sheet. In particular, when the laminate sheet is used as a decorative wall sheet (wallpaper), it is preferable that the laminate sheet has a foamed resin layer. On the other hand, the laminate sheet may not have a foamed resin layer. Furthermore, the laminate sheet in the present disclosure may be a sheet before the foamed resin layer is formed. In this case, the laminate sheet has a foaming agent-containing resin layer, which will be described later.

The foamed resin layer contains a resin. The foamed resin layer may contain a cured product of the above-mentioned resin. Examples of the above-mentioned resin include thermoplastic resins. Examples of thermoplastic resins include polyvinyl chloride resins, olefin resins, polystyrene resins, acrylonitrile-butadiene-styrene copolymers (ABS resins), acrylonitrile-styrene copolymers, nylon, polyacetal resins, acrylic resins, polycarbonate resins, polyester resins, polyvinyl acetate resins, polyvinyl alcohol resins, and polyurethane resins.

The foamed resin layer preferably contains an olefin-based resin. Examples of olefin-based resins include polyolefins, olefin vinyl ester copolymers, olefin-unsaturated carboxylic acid copolymers, and olefin-unsaturated carboxylic acid ester copolymers.

Examples of polyolefins include polyethylene (PE) and polypropylene (PP), with PE being preferred. Examples of PE include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), and linear low-density polyethylene (LLDPE).

Olefin-vinyl ester copolymers are copolymers containing olefins and vinyl esters as monomer components, and may be binary, ternary, or higher copolymers. Examples of the olefins include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, and 1-dodecene. Examples of the vinyl esters include vinyl acetate, vinyl caproate, vinyl propionate, vinyl caprylate, vinyl laurate, and vinyl stearate.

Specific examples of olefin vinyl ester copolymers include ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl caproate copolymer, ethylene-vinyl propionate copolymer, ethylene-vinyl caprylate copolymer, ethylene-vinyl laurate copolymer, and ethylene-vinyl stearate copolymer.

Olefin-unsaturated carboxylic acid copolymers are copolymers containing an olefin and an unsaturated carboxylic acid as monomer components, and may be binary, ternary, or higher copolymers. Examples of the olefins include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, and 1-dodecene. Examples of the unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, and fumaric acid.

Specific examples of olefin-unsaturated carboxylic acid copolymers include ethylene-acrylic acid copolymer (EAA) and ethylene-methacrylic acid copolymer (EMAA).

Examples of olefin unsaturated carboxylic acid ester copolymers include ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl methacrylate copolymer (EMMA), and ethylene-ethyl methacrylate copolymer (EEMA).

The foamed resin layer may contain an inorganic filler. The addition of an inorganic filler improves flame retardancy. Examples of inorganic fillers include calcium carbonate, aluminum hydroxide, magnesium hydroxide, antimony trioxide, zinc borate, molybdenum compounds, and titanium dioxide. The content of the inorganic filler is, for example, 30 parts by mass or more and 150 parts by mass or less, or may be 40 parts by mass or more and 100 parts by mass or less, relative to 100 parts by mass of the resin constituting the foamed resin layer. The average particle diameter ( _D50 ) of the inorganic filler is, for example, 5 μm or more and 25 μm or less, or may be 5 μm or more and 15 μm or less.

The foamed resin layer has air bubbles inside. The air bubbles may be closed or open. The foamed resin layer may also contain a mixture of closed and open cells. The air bubbles are formed by the foaming of the foaming agent contained in the foaming agent-containing resin layer, and there are no particular restrictions on the number, size, density, or shape of the bubbles.

The foamed resin layer may contain additives such as pigments, antioxidants, light stabilizers, crosslinking agents, crosslinking aids, foaming aids, insect repellents, preservatives, antibacterial agents, diluents, deodorizers, and plasticizers, as needed. The foamed resin layer may also contain unfoamed foaming agents. The thickness of the foamed resin layer may be, for example, 350 μm or more and 1500 μm or less, or 500 μm or more and 1200 μm or less.

The method for forming the foamed resin layer is not particularly limited, but examples include heating and foaming a foaming-agent-containing resin layer containing a resin and a foaming agent to form a foamed resin layer. Examples of foaming agents include organic thermally decomposable foaming agents. Examples of organic thermally decomposable foaming agents include azo-based foaming agents such as azodicarbonamide (ADCA) and azobisformamide, and hydrazide-based foaming agents such as oxybenzenesulfonylhydrazide (OBSH) and paratoluenesulfonylhydrazide. Other examples of foaming agents include inorganic foaming agents such as sodium bicarbonate. The foaming agent may also be a microcapsule-type foaming agent. Examples of methods for forming the foaming-agent-containing resin layer include extrusion film formation using an extruder such as a T-die extruder.

(2) Non-foamed resin layer The laminate sheet may have a non-foamed resin layer between the substrate layer and the surface protective layer. The non-foamed resin layer is a layer that does not contain bubbles caused by foaming of a foaming agent. When the laminate sheet has a foamed resin layer, the non-foamed resin layer may be disposed on the surface of the foamed resin layer facing the substrate layer, or on the surface of the foamed resin layer facing the surface protective layer. On the other hand, the laminate sheet does not have to have a non-foamed resin layer.

Here, the non-foamed resin layer disposed on the surface of the foamed resin layer facing the substrate layer is referred to as non-foamed resin layer A. The provision of non-foamed resin layer A improves the adhesion between the foamed resin layer and the substrate layer. Non-foamed resin layer A contains a resin and may contain a cured product of the resin. Details of non-foamed resin layer A are the same as those described above in "(1) Foamed Resin Layer" except for the use of a foaming agent, and therefore will not be repeated here. Non-foamed resin layer A and the foamed resin layer may contain the same type of resin or different types of resin. The thickness of non-foamed resin layer A is, for example, 5 μm or more and 50 μm or less.

The non-foamed resin layer disposed on the surface of the foamed resin layer facing the surface protection layer is referred to as non-foamed resin layer B. The provision of non-foamed resin layer B can, for example, improve the design of the decorative layer or the scratch resistance of the foamed resin layer. Non-foamed resin layer B contains a resin and may contain a cured product of the resin. Details of non-foamed resin layer B are the same as those described above in "(1) Foamed Resin Layer" except for the use of a foaming agent, and therefore will not be repeated here. Non-foamed resin layer B and the foamed resin layer may contain the same type of resin or different types of resin. The thickness of non-foamed resin layer B is, for example, 5 μm or more and 10 μm or less. The laminate sheet may have both non-foamed resin layer A and non-foamed resin layer B.

Examples of methods for forming the non-foamed resin layer include extrusion film formation using an extruder such as a T-die extruder.

(3) Decorative Layer The laminate sheet may have a decorative layer between the base layer and the surface protective layer. Providing a decorative layer improves the design of the laminate sheet. On the other hand, the laminate sheet does not have to have a decorative layer. When the laminate sheet has a foamed resin layer, the decorative layer is preferably disposed between the foamed resin layer and the surface protective layer. When the laminate sheet has a non-foamed resin layer, the decorative layer is preferably disposed between the non-foamed resin layer and the surface protective layer. The laminate sheet may also have a decorative layer on the surface of the surface protective layer opposite to the base layer. When the laminate sheet is viewed in plan in the thickness direction, the decorative layer may be disposed on the entire surface of the laminate sheet, or may be disposed on a part of the laminate sheet.

Examples of decorative layers include solid layers (layers coated with ink) and pattern layers (layers printed with ink). Examples of patterns in pattern layers include wood grain, stone grain, sand grain, tiled patterns, brickwork patterns, fabric patterns, leather-striped patterns, geometric shapes, letters, symbols, abstract patterns, and floral patterns.

The decorative layer typically contains a colorant and a binder resin. Examples of colorants include inorganic pigments such as carbon black (ink), iron black, titanium white, antimony white, yellow lead, titanium yellow, red iron oxide, cadmium red, ultramarine blue, and cobalt blue; organic pigments (including dyes) such as quinacridone red, isoindolinone yellow, nickel azo complex, phthalocyanine blue, and azomethine azo black; metal pigments such as aluminum and brass; and pearl pigments such as titanium dioxide-coated mica and basic lead carbonate.

Examples of binder resins include urethane-based resins, acrylic polyol-based resins, acrylic resins, ester-based resins, amide-based resins, butyral-based resins, styrene-based resins, urethane-acrylic copolymers, vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-acrylic copolymers, chlorinated propylene-based resins, nitrocellulose-based resins, and cellulose acetate-based resins.

The decorative layer may contain additives such as UV absorbers, light stabilizers, curing agents, plasticizers, and catalysts as needed. The thickness of the decorative layer is, for example, 0.5 μm or more and 20 μm or less, or 1 μm or more and 10 μm or less, or 2 μm or more and 5 μm or less. The decorative layer may be formed, for example, by applying an ink containing a colorant, binder resin, and solvent, followed by drying.

(4) Primer Layer The laminate sheet may have a primer layer on the surface of the surface protective layer facing the substrate layer. By providing the primer layer, the adhesion between the substrate layer and the surface protective layer is improved, and for example, a decrease in interlayer adhesion upon exposure to ultraviolet light can be suppressed. Furthermore, by providing the primer layer, the scratch resistance of the surface protective layer is improved. Furthermore, the laminate sheet may have a primer layer (rear primer layer) on the surface of the substrate layer opposite the surface protective layer.

The primer layer contains at least a binder resin. Examples of binder resins include urethane-based resins, acrylic polyol-based resins, acrylic resins, ester-based resins, amide-based resins, butyral-based resins, styrene-based resins, urethane-acrylic copolymers, polycarbonate-based urethane-acrylic copolymers, vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-acrylic copolymers, chlorinated propylene-based resins, nitrocellulose-based resins, and cellulose acetate-based resins. The primer layer may contain only one type of resin, or two or more types.

The primer layer may contain a cured binder resin. Examples of curing agents include isocyanate-based curing agents and epoxy-based curing agents. The cured binder resin is preferably a cured product obtained by crosslinking and curing a polyol resin, such as an acrylic polyol resin, with an isocyanate-based curing agent.

The primer layer may further contain at least one of an ultraviolet absorber and a light stabilizer. Conventional ultraviolet absorbers and light stabilizers can be used. The thickness of the primer layer is, for example, 0.01 μm or more and 10 μm or less, or 0.7 μm or more and 8 μm or less, or 1 μm or more and 6 μm or less. The primer layer may be formed, for example, by applying a resin composition containing a binder resin and a solvent, followed by drying. A curing treatment may be performed as necessary.

(5) Film Layer The laminate sheet may have a film layer between the substrate layer and the surface protective layer. Providing a film layer improves the strength of the laminate sheet. In particular, when the laminate sheet is used as a decorative floor sheet, it is preferable that the laminate sheet have a film layer. This is because decorative floor sheets are required to have high strength. When the laminate sheet has a primer layer, it is preferable that the film layer be disposed between the substrate layer and the primer layer. Furthermore, when the laminate sheet has a decorative layer, it is preferable that the film layer be disposed between the decorative layer and the surface protective layer. This is because the film layer can effectively protect the decorative layer.

The film layer may be transparent, translucent, or opaque. The film layer may be colored or uncolored. If the laminate sheet has a decorative layer, it is preferable that the film layer have transparency that allows the decorative layer to be identified.

The film layer contains a resin. Examples of such resins include olefin-based resins, methacrylic resins, polyvinyl alcohol-based resins, and fluorine-based resins. The resins may be acid-modified. Examples of olefin-based resins include polyolefins and olefin copolymers. Examples of polyolefins include polyethylene, polypropylene, polybutene, polybutadiene, and polyisoprene, with polyethylene being preferred.

The olefin copolymer is not particularly limited, but an ethylene copolymer containing ethylene is preferred. Examples of ethylene copolymers include ethylene-α,β-unsaturated carboxylic acid ester copolymers. Examples of ethylene-α,β-unsaturated carboxylic acid ester copolymers include ethylene-methacrylic acid copolymer (EMAA).

The thickness of the film layer is, for example, 3 μm or more and 25 μm or less, and may be 5 μm or more and 20 μm or less. The film layer can be formed, for example, by extrusion using an extruder such as a T-die extruder. Alternatively, the film layer may be prepared in advance and then thermally laminated with other layers. If necessary, a curing process may be performed.

(6) Adhesive Layer The laminate sheet may have an adhesive layer. The position of the adhesive layer is not particularly limited. When the laminate sheet has a foamed resin layer, the adhesive layer may be disposed on the surface of the foamed resin layer opposite the substrate layer. When the laminate sheet has a non-foamed resin layer B, the adhesive layer may be disposed on the surface of the non-foamed resin layer B opposite the substrate layer. When the laminate sheet has a film layer, the adhesive layer may be disposed between the substrate layer and the film layer. When the laminate sheet has a decorative layer, the adhesive layer may be disposed on the surface of the decorative layer opposite the substrate layer. When the substrate layer is a laminate of two or more layers, an adhesive layer may be disposed between each layer constituting the substrate layer. The laminate sheet may also have an adhesive layer on the surface of the substrate layer opposite the surface protective layer. In this case, the laminate sheet may have a peelable separator layer on the surface of the adhesive layer opposite the substrate layer.

The adhesive layer contains a resin. Examples of such resins include ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), ethylene-(meth)acrylic acid copolymer (EMAA), acrylic resins, styrene resins, polyester resins, urethane resins, chlorinated polyolefin resins, vinyl chloride-vinyl acetate copolymer resins, polyvinyl butyral resins, alkyd resins, petroleum resins, ketone resins, epoxy resins, melamine resins, fluorine-based resins, silicone resins, cellulose derivatives, and rubber resins.

The thickness of the adhesive layer is, for example, 0.1 μm or more and 10 μm or less. The adhesive layer can be formed, for example, by applying a resin composition containing a resin and a solvent, followed by drying.

(7) Laminate Sheet The laminate sheet according to the present disclosure includes at least a base layer and a surface protective layer. As described above, the laminate sheet may further include other layers such as a foamed resin layer, a non-foamed resin layer, a decorative layer, a primer layer, a film layer, and an adhesive layer.

The laminate sheet may have an embossed pattern on the outermost surface of the surface protection layer, relative to the base layer. In particular, it is preferable that the embossed pattern be located on the surface of the surface protection layer opposite the base layer. Because the surface protection layer of the present disclosure has good heat resistance, the laminate sheet will have good antiviral properties even after heat treatment to form an embossed pattern. Examples of embossed patterns include wood grain vascular grooves, stone slab surface irregularities, cloth surface texture, matte finish, sand grain, hairline, and linear grooves.

One method for forming an embossed pattern is to heat the laminated sheet and press it with an embossing plate. The heating temperature for the laminated sheet is, for example, 80°C or higher and 260°C or lower, or may be 85°C or higher and 200°C or lower, or 100°C or higher and 180°C or lower.

The laminate sheet in this disclosure is typically a decorative sheet, and is generally used as a building material. Specific examples include (1) to (5) below.

(1) Surface materials for interior walls, floors, ceilings, etc. of buildings such as houses, offices, stores, hospitals, clinics, etc. (2) Surface materials for exterior walls, roofs, eaves ceilings, door pockets, etc. of buildings such as houses, offices, stores, hospitals, clinics, etc. (3) Surface materials for fixtures such as windows, window frames, doors, door frames, etc. (4) Surface materials for fixtures such as handrails, waist walls, moldings, thresholds, lintels, and cappings (5) Surface materials for outdoor (exterior) parts such as fences, gates, drying rack pillars, and handrails

The laminate sheet in the present disclosure may be a transfer sheet. For example, if the laminate sheet has the decorative layer described above, the laminate sheet may be a transfer sheet for transferring the decorative layer. The laminate sheet may also be a transfer sheet for transferring the surface protection layer. As described above, the laminate sheet may also have an adhesive layer as appropriate depending on its intended use.

The present disclosure also provides a method for manufacturing a laminate sheet having a base layer and a surface protective layer, the method comprising: a precursor sheet manufacturing step of forming a precursor sheet by forming the surface protective layer containing a resin component, a cationic polymer-based antiviral agent A, and a silver-based or silver-zinc-based antiviral agent B on one surface of the base layer; and a heat treatment step of heat-treating the precursor sheet. The heat treatment step can be any step of heat-treating a precursor sheet for a laminate sheet. For example, the heating step is a step of foaming a foaming-agent-containing resin layer. Another example of the heating step is a step of forming an embossed pattern.

This disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical concept described in the claims of this disclosure and exhibits similar effects is encompassed within the technical scope of this disclosure.

[Example 1]
(Preparation of resin composition containing a foaming agent)
The following materials were melt-kneaded to obtain a resin composition containing a foaming agent.
Resin: EMAA "N1560: manufactured by DuPont-Mitsui Polychemicals Co., Ltd."... 100 parts by weight Inorganic filler: Titanium dioxide "CR58-2: manufactured by Ishihara Sangyo Kaisha, Ltd."... 20 parts by weight Foaming agent: Azo foaming agent "Vinihole AC#3: manufactured by Eiwa Chemical Industry Co., Ltd."... 4 parts by weight Foaming assistant: Hydrazide foaming assistant "ADH: manufactured by Otsuka Chemical Co., Ltd."... 2 parts by weight

(Preparation of EB coating agent)
The following materials were mixed to obtain an EB coating agent.
・Electron beam curing resin coating agent "Seika Beam: manufactured by Dainichiseika Color & Chemicals Co., Ltd."...100 parts by weight ・Antiviral agent A: Cationic polymer-based antiviral agent "Amorden D-CL50: manufactured by Daiwa Chemical Industry Co., Ltd."...1 part by weight ・Antiviral agent B: Silver-based antiviral agent "Novalon IV-1000: manufactured by Toagosei Co., Ltd."...9 parts by weight

(Preparation of laminated sheet)
A resin composition containing a foaming agent was formed into a film having a thickness of 50 μm or more and 100 μm or less, to obtain a foaming agent-containing resin layer. One side of the obtained foaming agent-containing resin layer was laminated to a backing paper (substrate layer). Next, an EB coating agent was applied to the other side of the foaming agent-containing resin layer using a gravure printing machine. Then, electron beam irradiation was performed under conditions of 200 kV and 50 kGy to form a surface protective layer. Next, the foaming agent-containing resin layer was foamed by heating at 220°C for 40 seconds in a gear oven, to obtain a laminate sheet (foamed laminate sheet).

[Example 2]
A laminate sheet was obtained in the same manner as in Example 1, except that the amount of antiviral agent A used was changed to 2.5 parts by mass.

[Example 3]
A laminated sheet was obtained in the same manner as in Example 1, except that the resin in the resin composition containing a foaming agent was changed to EVA "P1007 (VA content 10%): manufactured by DuPont-Mitsui Polychemicals Co., Ltd."

[Example 4]
A laminate sheet was obtained in the same manner as in Example 1, except that the antiviral agent A was changed to "FC-V20S: manufactured by Fuji Chemical Industry Co., Ltd.."
[Example 5]
A laminated sheet was obtained in the same manner as in Example 1, except that the antiviral agent B was changed to a silver-zinc antiviral agent “Amtech Clean Z: Amtech Co., Ltd.”

[Comparative Example 1]
A laminate sheet was obtained in the same manner as in Example 1 except that the antiviral agent A and the antiviral agent B were not used.

[Comparative Example 2]
A laminated sheet was obtained in the same manner as in Example 1, except that the antiviral agent A was changed to a quaternary ammonium salt-based antiviral agent "Suramoni D100: manufactured by Osaka Gas Chemicals Co., Ltd." and the amount of antiviral agent A used was changed to 3 parts by mass.

[Comparative Example 3]
A laminated sheet was obtained in the same manner as in Example 1, except that antiviral agent B was changed to a silver-copper-based antiviral agent “Zeomic AC10N: manufactured by Sinanen Zeomic Co., Ltd.”

[Comparative Example 4]
A laminate sheet was obtained in the same manner as in Example 1, except that the antiviral agent A was not used and the amount of the antiviral agent B used was changed to 18 parts by mass.

[evaluation]
(antiviral)
The antiviral properties of the laminated sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 4 were evaluated. Specifically, the tests were conducted in accordance with ISO 21702 (Determination of antiviral activity of plastics and other non-porous surfaces). The details of the tests are as follows.

0.4 ml of virus solution was dropped onto 5 cm square test pieces (antiviral-treated and untreated products) and covered with a 4 cm square film. The test pieces were left to stand at 25°C for 24 hours. After standing, the virus on the test pieces was washed off and recovered, and the virus infectivity was measured. The antiviral activity value was calculated using the following formula.
R = Ut - At
R is the antiviral activity value, Ut is the average common logarithm of the viral infectivity (PFU/ ^cm2 ) of untreated products after standing for 24 hours, and At is the average common logarithm of the viral infectivity (PFU/ ^cm2 ) of antiviral-treated products after standing for 24 hours. Influenza virus was used as the test virus, and an antiviral activity value of 2.0 or more was evaluated as O, and an antiviral activity value of less than 2.0 was evaluated as X.

(Stain resistance)
The stain resistance of the laminated sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 4 was evaluated. Specifically, the test was conducted in accordance with the "Stain-Resistant Wallpaper Performance Standards" established by the Wallpaper Industry Association. The details of the test are as follows.

Contaminants (coffee, soy sauce, crayon, water-based pen, oil-based pen) were applied to the surface protective layer of the laminate sheet, and after 24 hours, the coffee and soy sauce were wiped off with water, the crayon and water-based pen with a neutral detergent, and the oil-based pen with a dry wipe. The surface protective layer after wiping was visually inspected. The surface protective layer after wiping was compared with a surface protective layer without any contaminants, and grades 4 (contamination on the stain-only gray scale of about No. 4) or 5 (contamination on the stain-only gray scale of about No. 5) were rated as good, and grades 3 (contamination on the stain-only gray scale of about No. 3) or lower were rated as bad.

(heat resistance)
The heat resistance of the laminate sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 4 was evaluated. A spectrophotometer (CM-3700A, manufactured by Konica Minolta, Inc.) was used as the measuring device. Δb* was calculated using the b ^* value (b ^*1 ) of the laminate sheet obtained in Comparative Example 1 and the b ^* value (b ^*2 ) of the laminate sheets obtained in Examples 1 to 5 and Comparative Examples 2 to 4. Δb ^* was evaluated as ○ when it was less than 0.5, as △ when it was 0.5 or more and less than 1.0, and as × when ^it was 1 or more.

(Lightfastness)
The light resistance of the laminate sheets obtained in Examples 1 to 5 and Comparative Examples 1 to 4 was evaluated. Specifically, the laminate sheets were subjected to an accelerated test using an ultraviolet autofade meter, and changes in appearance were evaluated. The details of the test are as follows.

First, a spectrophotometer (CM-3700A, manufactured by Konica Minolta) was used as the measuring device. Next, an accelerated test was performed on the laminate sheet using an ultraviolet autofade meter (manufactured by Suga Test Instruments) under conditions of an illuminance of 500 W/ ^m2 , a black panel temperature of 63°C, and 100 hours. The Δb ^* of the laminate sheet before and after the accelerated test was determined. A Δb* of less than 0.5 was evaluated as ◯, a Δb ^* of 0.5 or more but less than 1.0 was evaluated as △, and a Δb* of 1 or more was evaluated as ×.

As shown in Table 1, Examples 1 to 5 all exhibited good antiviral properties, stain resistance, heat resistance, and light resistance. In contrast, Comparative Example 1 did not use an antiviral agent, and therefore did not achieve good results in the antiviral property evaluation. Comparative Example 2 did not achieve good results in the heat resistance evaluation. This is thought to be due to the low heat resistance of the quaternary ammonium salt-based antiviral agent. Comparative Example 3 did not achieve good results in the heat resistance and light resistance evaluation. This is thought to be due to the low light resistance of the silver-copper-based antiviral agent. Comparative Example 4 did not achieve good results in the stain resistance and light resistance evaluation. This is thought to be due to the proportion of antiviral B being too high.

REFERENCE SIGNS LIST 1... base material layer 2... surface protective layer 3... foamed resin layer 4... decorative layer 5... film layer 6... primer layer 10... laminated sheet

Claims (13)

A laminated sheet used in building materials,
The laminate sheet has a base layer and a surface protective layer,
The surface protective layer is
A resin component,
a cationic polymer antiviral agent A;
a silver-based or silver-zinc-based antiviral agent B;
Contains
the antiviral agent A is an antiviral agent having a quaternary ammonium base in at least one of a main chain and a side chain,
The surface protective layer of the laminate sheet contains, as the resin component, a cured product of an electron beam curable resin composition . 2. The laminate sheet according to claim 1, wherein the antiviral agent B is a silver-based antiviral agent. 2. The laminate sheet according to claim 1, wherein the antiviral agent B is a silver-zinc based antiviral agent. 3. The laminate sheet according to claim 1, wherein a content of the antiviral agent A in the surface protective layer is 0.5 parts by mass or more and 15 parts by mass or less relative to 100 parts by mass of the resin component. 4. The laminate sheet according to claim 1, wherein a content of the antiviral agent B in the surface protective layer is 0.5 parts by mass or more and 15 parts by mass or less relative to 100 parts by mass of the resin component. 6. The laminate sheet according to claim 1, wherein in the surface protective layer, a total content of the antiviral agent A and the antiviral agent B is 1 part by mass or more and 20 parts by mass or less per 100 parts by mass of the resin component. The laminate sheet described in any one of claims 1 to 6, wherein the surface protective layer is on the outermost surface. The laminate sheet described in any one of claims 1 to 7, wherein the laminate sheet has a foamed resin layer between the base layer and the surface protective layer. The laminate sheet according to claim 8, wherein the laminate sheet has a non-foamed resin layer A on the surface of the foamed resin layer facing the base layer, and a non-foamed resin layer B on the surface of the foamed resin layer facing the surface protection layer. The laminate sheet described in any one of claims 1 to 9, wherein the laminate sheet has an embossed pattern on the outermost surface of the laminate sheet facing the surface protection layer relative to the base layer. The laminate sheet according to any one of claims 1 to 10, wherein the laminate sheet has a decorative layer between the base layer and the surface protective layer. The laminate sheet described in any one of claims 1 to 11, wherein the laminate sheet is a decorative wall sheet. The laminate sheet according to any one of claims 1 to 11, wherein the laminate sheet is a decorative floor sheet.