Allergen-reducing decorative sheet, allergen-reducing adhesive processed sheet using same, and allergen-reducing decorative board

Abstract

The present invention provides an allergen-reducing decorative sheet which can exhibit high allergen-reducing performance even when a surface protection layer contains a small amount of an allergen-reducing agent and which exhibits the allergen-reducing performance for a long term.　The present invention provides an allergen-reducing decorative sheet comprising at least a surface protection layer, said allergen-reducing decorative sheet being characterized in that (1) the surface protection layer contains an allergen-reducing agent and a cured product of a crosslinking curable resin component, (2) the allergen-reducing agent contains a phenol-based polymer, and (3) the surface protection layer further contains at least two types of ultraviolet absorbers having a benzotriazole skeleton.

Description

Allergen-reduced decorative sheet, allergen-reduced adhesive sheet and allergen-reduced decorative board using the same

[0001] The present invention relates to an allergen-reduced decorative sheet, an allergen-reduced adhesive sheet using the same, and an allergen-reduced decorative board.

[0002] Conventionally, various decorative sheets have been used for the surface decoration of building interior materials such as fixtures, floors, and walls. For example, decorative sheets composed of a laminate having, in order in the thickness direction, a base sheet, a transparent resin layer, and a surface protective layer have been widely used, and it is known that, if necessary, a decorative layer may be provided on the base sheet, a primer layer may be provided between the transparent resin layer and the surface protective layer to improve adhesion, or an ionizing radiation-curable resin may be included in the resin component of the surface protective layer to improve the scratch resistance of the surface protective layer.

[0003] As an example of imparting functionality to a decorative sheet, a decorative sheet having allergen-reducing properties is known. For example, Patent Document 1 discloses a decorative sheet that can exhibit high allergen-reducing properties even with a small amount of allergen-reducing agent.

[0004] However, in Patent Document 1, even though the amount of allergen reducing agent is small, it is added in an amount of 10 to 30 parts by mass per 100 parts by mass of the curable resin composition (see claim 1). Furthermore, the curable resin composition contains 50% by mass or more of a urethane (meth)acrylate oligomer having hexa- or higher functionality (see claim 1), which is too hard for use as a decorative sheet for building materials. Therefore, if the amount of allergen reducing agent added is 10 parts by mass or more, the required performance as a surface protective layer will decrease, and it is expected that a harder resin will need to be used.

[0005] Furthermore, Patent Document 1 describes the addition of various additives to a curable resin composition used as a surface protective layer (see claim 4, etc.). However, Patent Document 1 describes that the additives are added merely for the purpose of imparting the effects of each additive to the surface protective layer, and does not consider the possibility that excellent allergen-reducing performance can be achieved even when the amount of allergen-reducing agent added in the surface protective layer is small, due to a synergistic effect of further improving the allergen-reducing performance exhibited by the allergen-reducing agent.

[0006] Furthermore, decorative sheets have the problem that their allergen-reducing performance deteriorates with long-term use. For this reason, there is a demand for decorative sheets that can exhibit high allergen-reducing performance even with small amounts of allergen-reducing agent added, that perform satisfactorily in allergen-reducing performance evaluations, and that exhibit long-lasting allergen-reducing performance, but there is room for further investigation into methods for achieving this.

[0007] Therefore, there is a need for the development of an allergen-reducing decorative sheet that can exhibit high allergen-reducing performance even when the amount of allergen-reducing agent added to the surface protective layer is small, and that exhibits long-lasting allergen-reducing performance.

[0008] JP 2012-171195 A

[0009] An object of the present invention is to provide an allergen-reduced decorative sheet that exhibits high allergen-reducing performance even when the amount of allergen-reducing agent added to the surface protective layer is small, and that exhibits long-lasting allergen-reducing performance. Another object of the present invention is to provide an allergen-reduced adhesive sheet and an allergen-reduced decorative board that use the decorative sheet.

[0010] As a result of extensive research, the inventors have discovered that the above-mentioned object can be achieved by providing a decorative sheet having a surface protective layer containing a cured product of a cross-linking curable resin component, a specific allergen reducing agent, and at least two or more types of ultraviolet absorbers having a benzotriazole skeleton, and have thus completed the present invention.

[0011] That is, the present invention relates to the following allergen-reduced decorative sheet, and an allergen-reduced adhesive sheet and allergen-reduced decorative board using the same. 1. An allergen-reduced decorative sheet having at least a surface protective layer, characterized in that: (1) the surface protective layer contains a cured product of a cross-linking curable resin component and an allergen-reducing agent; (2) the allergen-reducing agent contains a phenolic polymer; and (3) the surface protective layer further contains at least two or more ultraviolet absorbers having a benzotriazole skeleton. 2. The allergen-reduced decorative sheet according to item 1, wherein the content of the allergen-reducing agent in the surface protective layer is 1 part by mass or more and less than 15 parts by mass, based on 100 parts by mass of the cured product of the cross-linking curable resin component. 3. The allergen-reduced decorative sheet according to item 1 or 2, wherein the average particle size of the allergen-reducing agent is 1 μm or more and 15 μm or less. 4. Item 4. The allergen-reduced decorative sheet according to any one of Items 1 to 3, wherein the at least two or more UV absorbers having a benzotriazole skeleton exhibit different maximum absorption wavelengths. 5. The allergen-reduced decorative sheet according to any one of Items 1 to 4, wherein the UV absorbers include one UV absorber with a maximum absorption wavelength of less than 350 nm and one UV absorber with a maximum absorption wavelength of 350 nm or more. 6. The allergen-reduced decorative sheet according to any one of Items 1 to 5, wherein the UV absorbers include one UV absorber with a molecular weight of less than 300 and one UV absorber with a molecular weight of 300 or more. 7. The UV absorber is represented by the following formula (1): (In the formula, R １ and R ２are the same or different and represent hydrogen or a monovalent organic group, and X represents H, Cl, Br, or I.) The allergen-reduced decorative sheet according to any one of items 1 to 6, wherein the ultraviolet absorber is represented by the formula: 8. The allergen-reduced decorative sheet according to any one of items 1 to 7, wherein the content of the ultraviolet absorber in the surface protective layer is 0.5 parts by mass or more and 10 parts by mass or less, based on 100 parts by mass of the cured product of the cross-linking curable resin component. 9. The allergen-reduced decorative sheet according to any one of items 1 to 8, wherein the cross-linking curable resin component is an ionizing radiation curable resin component or a thermosetting resin component. 10. The allergen-reduced decorative sheet according to any one of items 1 to 9, wherein the surface protective layer contains an isocyanate component, and the isocyanate component is at least one selected from the group consisting of hexamethylene diisocyanate, isophorone diisocyanate, and hydrogenated diphenylmethane diisocyanate (MDI). 11. 11. The allergen-reduced decorative sheet according to any one of Items 1 to 10, wherein the surface protective layer contains a polyhydric alcohol, the polyhydric alcohol including 2,2,4-trimethyl-1,3-pentanediol. 12. The allergen-reduced decorative sheet according to any one of Items 1 to 11, wherein the surface protective layer contains an acrylic polyol component, the acrylic polyol component being at least one selected from the group consisting of methyl methacrylate (MMA), methacrylic acid, hydroxyethyl acrylate (HEA), and hydroxyethyl methacrylate (HEMA). 13. The allergen-reduced decorative sheet according to any one of Items 1 to 12, wherein the surface protective layer has a nanoindentation hardness of 80 MPa or more and 400 MPa or less. 14. The allergen-reduced decorative sheet according to any one of Items 1 to 13, which is composed of a laminate comprising at least a base sheet, a picture pattern layer, a transparent thermoplastic resin layer, and the surface protective layer, in that order in the thickness direction. 15. Item 15. The allergen-reduced decorative sheet according to Item 14, wherein at least one layer of the base sheet, the picture pattern layer, the transparent thermoplastic resin layer, and the surface protective layer contains a biomass-derived component.16. The allergen-reduced decorative sheet according to item 14 or 15, wherein at least one of the base sheet and the transparent thermoplastic resin layer comprises a chemically recycled polyolefin, which is a polyolefin obtained by polymerizing a monomer containing a chemically recycled olefin. 17. An allergen-reduced adhesive sheet comprising a laminate comprising, in order in the thickness direction, at least a pressure-sensitive adhesive sheet and the allergen-reduced decorative sheet according to any one of items 1 to 16. 18. An allergen-reduced decorative board comprising a laminate comprising, in order in the thickness direction, at least a decorative board substrate and the allergen-reduced decorative sheet according to any one of items 1 to 16. 19. An allergen-reduced decorative board comprising a laminate comprising, in order in the thickness direction, at least a decorative board substrate and the allergen-reduced adhesive sheet according to item 17.

[0012] The allergen-reduced decorative sheet of the present invention has a surface protective layer containing a cured product of a cross-linking curable resin component, a specific allergen-reducing agent, and at least two or more ultraviolet absorbers having a benzotriazole skeleton, so that even if the amount of allergen-reducing agent added to the surface protective layer is small, it can exhibit excellent allergen-reducing performance and can demonstrate long-lasting allergen-reducing performance. Furthermore, the allergen-reduced decorative sheet can be made into an allergen-reduced adhesive sheet by combining it with a pressure-sensitive adhesive sheet, and the allergen-reduced decorative sheet and the allergen-reduced adhesive sheet can each be made into an allergen-reduced decorative board by combining them with a decorative board substrate.

[0013] FIG. 1 is a cross-sectional schematic diagram showing an example of the allergen-reduced decorative sheet of the present invention (surface protective layer is composed of one layer). FIG. 2 is a cross-sectional schematic diagram showing an example of the allergen-reduced adhesive sheet of the present invention. FIG. 3 is a cross-sectional schematic diagram showing an example of a constituent member of the allergen-reduced decorative board of the present invention. FIG. 4 is a cross-sectional schematic diagram showing an example of the allergen-reduced decorative sheet of the present invention (surface protective layer is composed of two layers). FIG. 5 is a cross-sectional schematic diagram showing an example of the allergen-reduced adhesive sheet and allergen-reduced decorative board of the present invention obtained using a transfer method. FIG. 6 is a schematic diagram illustrating a Berkovich indenter (a) used in measuring nanoindentation hardness in this specification, the relationship between the load direction and indentation depth h (b), and the relationship between indentation depth and indentation load (c).

[0014] 1. Allergen-Reduced Decorative Sheet The allergen-reduced decorative sheet of the present invention (hereinafter also simply referred to as "decorative sheet") is a decorative sheet having at least a surface protective layer, characterized in that (1) the surface protective layer contains a cured product of a cross-linking curable resin component and an allergen-reducing agent, (2) the allergen-reducing agent contains a phenolic polymer, and (3) the surface protective layer further contains at least two or more ultraviolet absorbers having a benzotriazole skeleton.

[0015] The decorative sheet of the present invention having the above-mentioned characteristics contains at least two or more UV absorbers having a benzotriazole skeleton (hereinafter also referred to as "benzotriazole UV absorbers") in the surface protective layer. Benzotriazole UV absorbers are stable UV absorbers, and the inclusion of two or more such stable UV absorbers allows for long-lasting allergen reduction performance. In particular, the inclusion of two or more benzotriazole UV absorbers with different molecular weights allows the low-molecular-weight benzotriazole UV absorber to exhibit a strong UV absorption effect, while the high-molecular-weight benzotriazole UV absorber to exhibit a long-lasting UV absorption effect. Therefore, even with a small amount of allergen reducing agent added to the surface protective layer, excellent allergen reduction performance and long-lasting allergen reduction performance can be exhibited. Furthermore, the use of at least two or more UV absorbers having a benzotriazole skeleton in the surface protective layer allows for absorption of UV rays over a wide range of wavelengths, protecting the allergen reducing agent, and therefore allows for excellent allergen reduction performance to be exhibited even with a small amount of allergen reducing agent added to the surface protective layer.

[0016] As described above, the decorative sheet of the invention can exhibit excellent allergen-reducing performance even when the amount of allergen-reducing agent added to the surface protective layer is small, and can demonstrate long-lasting allergen-reducing performance. Furthermore, the decorative sheet can be combined with a pressure-sensitive adhesive sheet to form an allergen-reduced adhesive sheet, and the allergen-reduced decorative sheet and the allergen-reduced adhesive sheet can each be combined with a decorative board substrate to form an allergen-reduced decorative board.

[0017] The decorative sheet of the present invention is not limited in its specific configuration (layer configuration) as long as it contains a cured product of a cross-linking curable resin component and an allergen reducing agent containing a phenolic polymer in the surface protective layer, and further contains at least two or more types of ultraviolet absorbers having a benzotriazole skeleton.

[0018] In a specific embodiment, the decorative sheet of the present invention may be composed of a laminate comprising, in order in the thickness direction, for example, a base sheet, a transparent thermoplastic resin layer, and a surface protective layer. Alternatively, the decorative sheet of the present invention may be composed of a laminate comprising, in order in the thickness direction, for example, a base sheet, a picture pattern layer, a transparent thermoplastic resin layer, and a surface protective layer.

[0019] Figure 1 is a cross-sectional schematic diagram showing an example of a decorative sheet of the present invention. In Figure 1, a picture pattern layer 3, a transparent adhesive layer 4, a transparent thermoplastic resin layer 5, a primer layer 6, and a surface protective layer 7 are laminated in this order on a base sheet 2, and a back primer layer 8 is further provided on the back surface of the base sheet 2. Furthermore, the presence of an allergen reducing agent 9-1 and at least two or more ultraviolet absorbers 9-2 having a benzotriazole skeleton in the surface protective layer 7 is schematically shown. Furthermore, as shown in Figure 1 (II), the decorative sheet of the present invention may have an embossed uneven pattern.

[0020] The thickness of the surface protective layer cross-linked cured resin layer 7 is the thickness indicated by A in the figure, but the presence of allergen reducing agent 9-1 on the front surface side of the cross-linked cured resin layer 7 may form protrusions (convex portions) exceeding the thickness A as long as the surface performance is not impaired. Even when there is a protrusion on the outermost surface due to the allergen reducing agent 9-1, the thickness of the cross-linked cured resin layer 7 means the thickness A of the smooth portion excluding the protrusion on the outermost surface (this is the same for an embodiment having an embossed uneven pattern as shown in Figure 1 (II)). Here, while Figure 1 shows a slight protrusion due to the allergen reducing agent 9-1, this does not mean that the allergen reducing agent 9-1 itself is exposed, but rather is a protrusion as part of the surface protective layer.

[0021] 1 shows an example of a surface protective layer 7 having a single layer configuration, but as shown in Fig. 4, the surface protective layer 7 may have a two-layer configuration consisting of a first surface protective layer 7-1 and a second surface protective layer 7-2, and the first surface protective layer 7-1 may contain an allergen reducing agent 9-1 and at least two or more ultraviolet absorbers 9-2 having a benzotriazole skeleton. Even when the surface protective layer 7 has a two-layer configuration, the thickness of the surface protective layer 7 means thickness A (the sum of the thicknesses of 7-1 and 7-2) shown in Fig. 4 (this also applies to an embodiment having an embossed uneven pattern on the outermost surface, although this is not shown).

[0022] Furthermore, the present invention also encompasses an allergen-reducing adhesive sheet (hereinafter also referred to as "adhesive sheet") that is composed of a laminate comprising, in order in the thickness direction, at least an adhesive sheet and the decorative sheet of the present invention (for example, the embodiment shown in Figure 2). Note that Figure 2 illustrates the configuration of an adhesive sheet 11 that has an adhesive sheet 10 on the back surface of the decorative sheet 1 shown in Figure 1, but the configuration of the decorative sheet 1 is not limited to this.

[0023] Furthermore, the present invention also encompasses an invention (for example, an embodiment shown in FIG. 3) of an allergen-reducing decorative board (hereinafter also referred to as the "decorative board of the present invention") composed of a laminate comprising, in order in the thickness direction, at least a decorative board substrate and a decorative sheet of the present invention or a pressure-sensitive adhesive sheet of the present invention. Fig. 3 illustrates the configuration of a decorative board 13 having a decorative board substrate 12 on the back surface of the decorative sheet 1 shown in Fig. 1. Alternatively, the decorative board 13 may have a configuration in which a decorative board substrate 12 is provided on the back surface of the pressure-sensitive adhesive sheet 11 shown in Fig. 2.

[0024] 5 is a cross-sectional schematic diagram showing an example of an allergen-reduced adhesive sheet and allergen-reduced decorative board of the present invention obtained using a transfer method. In FIG. 5(I), a surface protective layer 7 and an adhesive sheet 10 are formed in that order on a release film 14. By using an allergen-reducing agent 9-1 with a larger specific gravity than the cross-linked curable resin, the allergen-reducing agent 9-1 can be precipitated in the cross-linked curable resin layer 7 and easily distributed near the release film 14. Next, in FIG. 5(II), the allergen-reduced adhesive sheet 11 of the present invention obtained by peeling off the release film 14 is laminated on a decorative board substrate 12 such as a building material to produce an allergen-reduced decorative board 13.

[0025] In this specification, the surface visible after application of the decorative sheet of the present invention, i.e., the side on which the surface protective layer is laminated as viewed from the base sheet, is referred to as the "upper" or "front side," and the side on which the back primer layer is laminated as viewed from the base sheet is referred to as the "lower" or "back side." This relationship is the same for the pressure-sensitive adhesive sheet of the present invention and the decorative laminate of the present invention.

[0026] In this specification, the expressions "contain" and "comprise" include the concepts of "contain," "include," "consist essentially of," and "consist only of."

[0027] Each layer of the decorative sheet of the present invention will be described below using Figures 1 and 4 as examples. However, the layer structure of the decorative sheet of the present invention is not limited to the embodiments shown in Figures 1 and 4, and various layer structures can be adopted as laminates, as mentioned above. In the following description, the lower and upper limits of numerical ranges expressed by "to" mean "greater than or equal to" (for example, if α to β, it means greater than or equal to α and less than or equal to β).

[0028] Surface Protective Layer The decorative sheet of the present invention has at least a surface protective layer, (1) the surface protective layer contains a cured product of a cross-linking curable resin component and an allergen reducing agent, (2) the allergen reducing agent contains a phenolic polymer, and (3) the surface protective layer further contains at least two or more ultraviolet absorbers having a benzotriazole skeleton.

[0029] In order to achieve better allergen reduction performance in the decorative sheet of the present invention, the surface protective layer is preferably the outermost protective layer (outermost layer) of the decorative sheet of the present invention.

[0030] (Cured product of cross-linked curable resin component) The surface protective layer contains a cured product of a cross-linked curable resin component. From the viewpoint of being able to combine the surface performance of the surface protective layer (any surface performance that a surface protective layer should originally have, such as scratch resistance, impact resistance, chemical resistance, etc.) in addition to allergen reduction performance, it is preferable that the resin component constituting the surface protective layer consists solely of a cross-linked curable resin component, that is, it is preferable that the surface protective layer is a cross-linked curable resin layer.

[0031] The cross-linking curable resin that forms the cured product of the cross-linking curable resin component is not particularly limited as long as it is transparent, and may be colorless and transparent, colored and transparent, translucent, or the like.

[0032] The crosslinking-curable resin component is a crosslinking-curable component, and may be a crosslinking-curable resin, as described below, or a prepolymer (including oligomer) and a monomer, or a mixture thereof. The surface protective layer of the decorative sheet of the present invention contains a cured product of the crosslinking-curable resin component. The crosslinking-curable resin component is not limited, but preferably contains an ionizing radiation-curable resin or a two-component curable urethane-based resin. It may also be an ionizing radiation-curable resin component or a two-component curable urethane-based resin component containing these prepolymers (including oligomers) and / or monomers. When the surface protective layer is formed from an ionizing radiation-curable resin component or a two-component curable urethane-based resin component, the abrasion resistance, impact resistance, contamination resistance, scratch resistance, weather resistance, etc. of the decorative sheet are easily improved. Among these, an ionizing radiation-curable resin component is preferred.

[0033] The ionizing radiation curable resin component is not particularly limited, and a transparent resin mainly composed of a prepolymer (including oligomer) and / or monomer containing a radically polymerizable double bond in the molecule that can undergo polymerization / crosslinking reaction upon irradiation with ionizing radiation such as ultraviolet light or electron beams can be used. These prepolymers or monomers can be used alone or in combination. The curing reaction is usually a crosslinking curing reaction.

[0034] Specifically, the prepolymer or monomer may be a compound having a radically polymerizable unsaturated group such as a (meth)acryloyl group or a (meth)acryloyloxy group, or a cationic polymerizable functional group such as an epoxy group in the molecule. Polyene / thiol-based prepolymers, which are a combination of polyene and polythiol, are also preferred. Here, the (meth)acryloyl group refers to an acryloyl group or a methacryloyl group.

[0035] Examples of prepolymers having a radically polymerizable unsaturated group include polyester (meth)acrylate, urethane (meth)acrylate, epoxy (meth)acrylate, melamine (meth)acrylate, triazine (meth)acrylate, and silicone (meth)acrylate. The weight-average molecular weight of these prepolymers is preferably about 250 to 100,000. The weight-average molecular weight in this specification is the average molecular weight measured by GPC analysis (gel permeation chromatography) and converted into standard polystyrene.

[0036] Examples of the monomer having a radically polymerizable unsaturated group include monofunctional monomers such as methyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, and phenoxyethyl(meth)acrylate. Examples of the polyfunctional monomers include diethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethylene oxide tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0037] Examples of prepolymers having a cationically polymerizable functional group include prepolymers of epoxy resins such as bisphenol epoxy resins and novolac epoxy compounds, and vinyl ether resins such as fatty acid vinyl ethers and aromatic vinyl ethers. Examples of thiols include polythiols such as trimethylolpropane trithioglycolate and pentaerythritol tetrathioglycolate. Examples of polyenes include those in which allyl alcohol is added to both ends of a polyurethane made from a diol and a diisocyanate.

[0038] In the present invention, a mixed resin containing a urethane (meth)acrylate oligomer (A) having two radically polymerizable unsaturated groups per molecule and a weight-average molecular weight of 1,000 to 3,000 and aliphatic urethane (meth)acrylate oligomer (B) having 3 to 15 radically polymerizable unsaturated groups per molecule can be used as the ionizing radiation-curable resin component. When such a mixed resin is used, effects such as scratch resistance and stain resistance are easily achieved due to the high crosslinking density, and there are also advantages in that the surface performance can be easily adjusted to suit the application, for example, by appropriately adjusting the weight-average molecular weight and / or the blend amount, to provide a surface protective layer with excellent impact resistance or excellent processability, such as V-cutting.

[0039] The contents of the oligomer (A) and the oligomer (B) in the ionizing radiation curable resin component are not limited, but when the ionizing radiation curable resin is taken as 100% by mass, it is preferable that the oligomer (A) be 50% by mass or more and the oligomer (B) be less than 50% by mass, and it is more preferable that the oligomer (A) be 50% by mass or more and 90% by mass or less and the oligomer (B) be 10% by mass or more and less than 50% by mass.

[0040] In the present invention, a mixed resin containing two types of aliphatic urethane (meth)acrylate, Resin A and Resin B shown below, can also be used as the ionizing radiation curable resin component. Here, (meth)acrylate means acrylate or methacrylate.

[0041] Resin A is an aliphatic urethane (meth)acrylate having an isocyanurate skeleton. While not limited as long as it satisfies this requirement, for example, an aliphatic urethane (meth)acrylate having an isocyanurate skeleton formed by a diisocyanate trimer is preferred. Specific examples include a trimer of hexamethylene diisocyanate (particularly 1,6-hexamethylene diisocyanate), a trimer of tolylene diisocyanate, and a trimer of meta-xylene diisocyanate. Because tolylene diisocyanate and meta-xylene diisocyanate have a benzene ring, they may have poorer weather resistance than hexamethylene diisocyanate, and therefore these diisocyanates are preferably hydrogenated. These resins A have the effect of improving the contamination resistance, alkali resistance, etc. of the surface protective layer (crosslinked cured resin layer).

[0042] Resin B is an aliphatic urethane (meth)acrylate that does not have an isocyanurate skeleton but has an alicyclic skeleton. While not limited as long as this requirement is met, it is preferable that the alicyclic skeleton contains at least one of isophorone and cyclohexane. Specific examples include a urethane oligomer, which is a polymer formed from isophorone diisocyanate and butanediol as monomers, to which an acrylate is added at the end, and a PG-modified diacrylate of hydrogenated dicyclohexylmethane diisocyanate (hydrogenated MDI). These resins B have the effect of imparting flexibility to the surface protective layer (crosslinked cured resin layer), and in combination with resin A, they provide the surface protective layer (crosslinked cured resin layer) with excellent contamination resistance, alkali resistance, etc. over a long period of time, as well as the effect of suppressing the occurrence of cracks and breakages when subjected to impact or during processing.

[0043] The ionizing radiation-curable resin component is a transparent resin primarily composed of a prepolymer (including oligomer) and / or monomer containing a radically polymerizable double bond in the molecule that can undergo a polymerization / crosslinking reaction upon irradiation with ionizing radiation such as ultraviolet light or an electron beam, and the curing reaction is typically a crosslinking reaction. The ionizing radiation used to cure the ionizing radiation-curable resin component is electromagnetic waves or charged particles having enough energy to cause a curing reaction of the molecules in the ionizing radiation-curable resin component. Ultraviolet light or an electron beam is usually used, but visible light, X-rays, ion beams, etc. may also be used. Among the ionizing radiation-curable resin components of the present invention, an electron beam-curable resin component is preferably used because it does not contain a photopolymerization initiator, allowing the properties of the raw material resin to be directly reflected in the properties of the resin component of the crosslinking-curable resin layer, and because it provides a wider range of options when a weathering agent is used in combination.

[0044] The two-component curing urethane-based resin is not particularly limited, but among them, a resin containing a polyol component having an OH group (acrylic polyol, polyester polyol, polyether polyol, epoxy polyol, etc.) as a main component and an isocyanate component (tolylene diisocyanate, hexamethylene diisocyanate, metaxylene diisocyanate, etc.) as a curing agent component can be used.

[0045] The above-exemplified cross-linked curable resins can be used alone or in combination of two or more.

[0046] The surface protective layer may also contain an isocyanate component, a polyhydric alcohol, or an acrylic polyol component.

[0047] The isocyanate component is not particularly limited, and examples thereof include hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate (MDI), etc. The isocyanate component may be used alone or in combination of two or more.

[0048] The polyhydric alcohol is not particularly limited, and examples thereof include 2,2,4-trimethyl-1,3-pentanediol, etc. The polyhydric alcohol may be used alone or in combination of two or more kinds.

[0049] The acrylic polyol is not particularly limited, and examples thereof include methyl methacrylate (MMA), methacrylic acid, hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate (HEMA), etc. The acrylic polyols can be used alone or in combination of two or more.

[0050] In recent years, the use of biomass-derived resins, which have a low environmental impact, has been widely studied, and the resin forming the surface protective layer of the decorative sheet of the present invention can also contain a biomass-derived component. Specifically, the biomass-derived component can be a urethane (meth)acrylate or the like made from a biomass-derived component. It is preferable that at least one of the polyol, isocyanate compound, and hydroxy (meth)acrylate components contained in the urethane (meth)acrylate contains a biomass-derived component.

[0051] (Allergen-reducing agent) The surface protective layer contains an allergen-reducing agent in addition to the cured product of the cross-linking curable resin component. In the present invention, the allergen-reducing agent contained in the surface protective layer includes a phenolic polymer.

[0052] The phenolic polymer is not particularly limited as long as it has a phenolic hydroxyl group in the molecule and can exhibit allergen-reducing performance. In the present invention, examples of phenolic polymers that can be used as allergen-reducing agents include water-insoluble polymers containing phenolic hydroxyl groups. Furthermore, supports in which a polyphenol compound is supported on an inorganic material such as an inorganic solid acid can also be used as the phenolic polymer. Among these, water-insoluble polymers containing phenolic hydroxyl groups are preferred from the viewpoint of exhibiting superior allergen-reducing performance even when added in small amounts.

[0053] As the water-insoluble polymer containing a phenolic hydroxyl group, commercially available products such as "Allerbuster (trade name)" manufactured by Sekisui Chemical Co., Ltd. and "Marukalinker M (trade name)" manufactured by Maruzen Oil Co., Ltd. can be used. These allergen reducing agents are particularly effective against various allergens such as dust mites and pollen.

[0054] The average particle size of the allergen-reducing agent is preferably from 0.5 μm to 15 μm, more preferably from 1 μm to 9 μm, even more preferably from 1.5 μm to 7 μm, and particularly preferably from 2 μm to 5 μm. By having the average particle size of the allergen-reducing agent within the above-mentioned range, the allergen-reducing agent is more easily lifted up to the surface layer in the surface protective layer, further improving the allergen-reducing performance of the decorative sheet of the present invention.

[0055] The content of the phenolic polymer is preferably 1 part by mass or more but less than 15 parts by mass, more preferably 1 part by mass or more but less than 10 parts by mass, even more preferably 1 part by mass or more but less than 10 parts by mass, particularly preferably 2 parts by mass or more but less than 8 parts by mass, and most preferably 3 parts by mass or more but less than 7 parts by mass, based on 100 parts by mass of the cured product of the cross-linking curable resin component. By having the content of the phenolic polymer within the above range, the decorative sheet of the present invention can exhibit better allergen-reducing performance even when a small amount of allergen-reducing agent is added.

[0056] The content of the phenolic polymer is preferably 0.1% by mass to 10% by mass, more preferably 0.5% by mass to less than 10% by mass, even more preferably 1% by mass to less than 10% by mass, particularly preferably 2% by mass to 8% by mass, most preferably 3% by mass to 7% by mass, and even most preferably 3% by mass to 6% by mass. By having the phenolic polymer content within the above range, the decorative sheet of the present invention can exhibit better allergen-reducing performance even when a small amount of allergen-reducing agent is added.

[0057] The surface protective layer may contain other allergen reducing agents in addition to the phenolic polymer, but from the viewpoint that it is preferable to exhibit excellent allergen reducing performance even when the amount of allergen reducing agent added is small, it is preferable that the allergen reducing agent consists only of a phenolic polymer.

[0058] The other allergen-reducing agents include inorganic compounds and organic compounds other than the phenolic polymers. These may be used alone or in combination of two or more different compounds. Furthermore, the inorganic compounds are preferably metal-supported materials.

[0059] As the inorganic material of the inorganic compound, for example, at least one selected from the group consisting of titanium oxide, calcium phosphate, calcium silicate, zirconium phosphate, zeolite, silica alumina, magnesium silicate, and magnesium phosphate is preferred, and among these, titanium oxide, zirconium phosphate, etc. are preferred.

[0060] The metal supported on the inorganic material is preferably at least one selected from the group consisting of silver, gold, platinum, zinc, and copper, and among these, zinc is preferred. Suitable commercially available products include "Atomy Ball TZ-R (trade name): zinc-supported titanium oxide" manufactured by JGC Catalysts and "Allerremove (trade name)" manufactured by Toagosei Co., Ltd. These allergen reducers are effective against various allergens such as dust mites and pollen.

[0061] Examples of organic compounds other than phenolic polymers include polymers containing at least one monomer component selected from the group consisting of styrene sulfonic acid and salts thereof.

[0062] As the at least one monomer component selected from the group consisting of styrene sulfonic acid and its salts, materials such as those disclosed in Japanese Patent No. 6136433 can be used.

[0063] As mentioned above, in the present invention, the allergen-reducing agent may be a combination of a phenolic polymer and an allergen-reducing agent other than the phenolic polymer. When a phenolic polymer and another allergen-reducing agent are used together as the allergen-reducing agent, the total content of the allergen-reducing agent (total amount of allergen-reducing agent) is preferably 1 part by mass or more but less than 15 parts by mass, more preferably 1 part by mass or more but less than 10 parts by mass, even more preferably 1 part by mass or more but less than 10 parts by mass, particularly preferably 2 parts by mass or more but less than 8 parts by mass, and most preferably 3 parts by mass or more but less than 7 parts by mass, based on 100 parts by mass of the cured product of the cross-linking curable resin component. By having the content of the allergen-reducing agent within the above range, the decorative sheet of the present invention can exhibit better allergen-reducing performance even when a small amount of allergen-reducing agent is added.

[0064] Furthermore, when a phenolic polymer and another allergen-reducing agent are used in combination as the allergen-reducing agent, the total content of these allergen-reducing agents (total amount of allergen-reducing agent), taken as 100% by mass of the surface protective layer, is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.5% by mass or more but less than 10% by mass, even more preferably 1% by mass or more but less than 10% by mass, particularly preferably 2% by mass or more and 8% by mass or less, most preferably 3% by mass or more and 7% by mass or less, and even most preferably 3% by mass or more and 6% by mass or less. By having the content of the allergen-reducing agent within the above range, the decorative sheet of the present invention can exhibit superior allergen-reducing performance even when a small amount of allergen-reducing agent is added.

[0065] (UV Absorber Having a Benzotriazole Skeleton) In the decorative sheet of the present invention, the surface protective layer contains at least two or more UV absorbers having a benzotriazole skeleton (hereinafter also referred to as "benzotriazole-based UV absorbers").

[0066] The benzotriazole-based ultraviolet absorber is not particularly limited as long as it has a benzotriazole skeleton and acts as an ultraviolet absorber. Specifically, a benzotriazole-based compound in which a hydrogen atom is bonded to a carbon atom forming the benzotriazole or the hydrogen atom is substituted with a halogen element, and a hydroxyphenyl group is bonded to a nitrogen atom forming the benzotriazole can be suitably used.

[0067] The benzotriazole-based ultraviolet absorber is preferably a benzotriazole-based ultraviolet absorber represented by the following formula (1):

[0068]

[0069] In the above formula (1), R １ and R ２ are the same or different and represent hydrogen or a monovalent organic group.

[0070] R １ Examples of the monovalent organic group represented by R include an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, and an arylalkyl group. An aliphatic hydrocarbon group such as an alkyl group or an alkenyl group is preferred, and an alkyl group is more preferred. １ The monovalent organic group may be either linear or branched.

[0071] R １ The alkyl group is preferably an alkyl group having 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 5 carbon atoms, such as a methyl group, an ethyl group, various propyl groups, various butyl groups, various pentyl groups, various hexyl groups, various octyl groups, various nonyl groups, various decyl groups, various undecyl groups, various dodecyl groups, various tridecyl groups, various tetradecyl groups, various pentadecyl groups, various hexadecyl groups, various heptadecyl groups, various octadecyl groups, various nonadecyl groups, and various icosyl groups. Among these, a methyl group and an ethyl group are preferred, and a methyl group is more preferred.

[0072] R ２Examples of the monovalent organic group represented by R include an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, and an arylalkyl group. An aliphatic hydrocarbon group such as an alkyl group or an alkenyl group is preferred, and an alkyl group is more preferred. ２ The monovalent organic group may be either linear or branched, and is preferably branched.

[0073] R ２ The alkyl group represented by the formula (I) preferably includes alkyl groups having 1 to 20 carbon atoms, more preferably 2 to 7 carbon atoms, and even more preferably 3 to 6 carbon atoms, such as methyl, ethyl, various propyl groups, various butyl groups, various pentyl groups, various hexyl groups, various octyl groups, various nonyl groups, various decyl groups, various undecyl groups, various dodecyl groups, various tridecyl groups, various tetradecyl groups, various pentadecyl groups, various hexadecyl groups, various heptadecyl groups, various octadecyl groups, various nonadecyl groups, and various icosyl groups. Among these, various propyl groups and various butyl groups are preferred, various butyl groups are more preferred, and t-butyl groups are even more preferred. Furthermore, R ２ is also preferably a hydrogen atom.

[0074] In the above formula (1), X represents H, Cl, Br, or I. Among these, H, Cl, and Br are preferred, and H and Cl are more preferred.

[0075] More specifically, as the benzotriazole-based ultraviolet absorber represented by the above formula (1), benzotriazole-based ultraviolet absorbers represented by the following formulas (2) and (3) can be suitably used.

[0076]

[0077] In the present invention, it is sufficient that the surface protective layer contains at least two or more ultraviolet absorbers having a benzotriazole skeleton, but it is preferable that the at least two or more ultraviolet absorbers have different maximum absorption wavelengths. By using two or more ultraviolet absorbers with different maximum absorption wavelengths, ultraviolet rays over a wider range of wavelengths can be absorbed, and the allergen-reducing agent is further protected, so that even if the amount of allergen-reducing agent added to the surface protective layer is small, better allergen-reducing performance can be achieved.

[0078] In the present invention, the benzotriazole-based UV absorber preferably contains an UV absorber (A) having a maximum absorption wavelength of less than 350 nm and an UV absorber (B) having a maximum absorption wavelength of 350 nm or more. By containing two or more UV absorbers within the above maximum absorption wavelength range, the benzotriazole-based UV absorber can absorb UV rays over a wider range of wavelengths, protecting the allergen-reducing agent. Therefore, even if the amount of allergen-reducing agent added to the surface protective layer is small, more excellent allergen-reducing performance can be achieved. The maximum absorption wavelength of the UV absorber (A) is preferably 250 nm or more and less than 350 nm, and even more preferably 300 nm or more and 345 nm or less. Furthermore, the maximum absorption wavelength of the UV absorber (B) is preferably 350 nm or more and 450 nm or less, and even more preferably 355 nm or more and 400 nm or less.

[0079] As the benzotriazole-based ultraviolet absorber, commercially available products can be used, such as Tinuvin 326, Tinuvin P, Tinuvin 399, and Tinuvin 328 manufactured by BASF, and LA-36 manufactured by ADEKA.

[0080] The molecular weight of the benzotriazole-based ultraviolet absorber is preferably 150 or more and 500 or less, more preferably 200 or more and 400 or less, and even more preferably 250 or more and 350 or less.

[0081] In the present invention, the benzotriazole-based UV absorber preferably contains an UV absorber A having a molecular weight of less than 300 and an UV absorber B having a molecular weight of 300 or more. By using UV absorbers A and B having different molecular weights, the low-molecular-weight benzotriazole-based UV absorber can exhibit a strong UV absorption effect, while the high-molecular-weight benzotriazole-based UV absorber can exhibit a long-lasting UV absorption effect. Therefore, even if the amount of allergen-reducing agent added to the surface protective layer is small, it is easier to exhibit superior allergen-reducing performance and long-lasting allergen-reducing performance. The molecular weight of the UV absorber A is more preferably 150 or more and less than 300, and even more preferably 200 or more and 280 or less. The molecular weight of the UV absorber B is more preferably 300 or more and 450 or less, and even more preferably 310 or more and 400 or less.

[0082] The content of the benzotriazole-based ultraviolet absorber in the surface protective layer is preferably 0.5 parts by mass or more and 10.0 parts by mass or less, more preferably 1 part by mass or more and 7 parts by mass or less, and even more preferably 2 parts by mass or more and 6 parts by mass or less, based on 100 parts by mass of the cured product of the cross-linking curable resin component. The content of the ultraviolet absorber is the total content of two or more ultraviolet absorbers.

[0083] (Light Stabilizer) In the decorative sheet of the present invention, the surface protective layer may further contain a light stabilizer.

[0084] Examples of light stabilizers include aromatic compounds, amine compounds, organic acid compounds, catechin compounds, and hindered amine compounds, and among these, hindered amine compounds are preferred. Hindered amine compounds have a structure containing a 2,2,6,6-tetramethylpiperidine skeleton in the molecule.

[0085] The base dissociation constant (pKb) of the light stabilizer is preferably 7 or more, more preferably 8 or more. When the lower limit of the base dissociation constant is within the above range, the crosslink density of the surface protective layer of the decorative sheet of the present invention is further improved. Furthermore, the upper limit of the base dissociation constant is not particularly limited and may be 11.

[0086] The content of the light stabilizer is preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 0.3 parts by mass or more and 8 parts by mass or less, still more preferably 1 part by mass or more and 5.0 parts by mass or less, and particularly preferably 1 part by mass or more and less than 5 parts by mass, relative to 100 parts by mass of the cured product of the cross-linking curable resin component. Note that it is preferable to contain a hindered amine compound as the light stabilizer in the above range.

[0087] (Other Additives) The surface protective layer constituting the decorative sheet of the present invention may further contain other additives in addition to the allergen reducing agent and benzotriazole-based UV absorber. Such additives include allergen reducing agents other than the allergen reducing agents described above, colorants such as dyes and pigments, fillers such as inorganic fillers, weather resistance agents, antifoaming agents, leveling agents, thixotropy-imparting agents, flame retardants, antibacterial agents other than the allergen reducing agents described above, etc. For example, the present invention can employ an embodiment in which, in addition to the allergen reducing agent described above, the surface protective layer further contains at least one selected from the group consisting of antibacterial agents and antiviral agents.

[0088] The antibacterial agents include inorganic antibacterial agents and organic antibacterial agents. In particular, inorganic antibacterial agents are desirable because they are generally safer than organic antibacterial agents and have excellent durability and heat resistance. In this specification, inorganic antibacterial agents are those in which antibacterial metals such as silver, copper, and zinc are supported on various inorganic carriers. Among these, silver-containing inorganic antibacterial agents (silver-containing inorganic particles) are preferred, and specifically, silver-supported zeolite particles are preferred. The antibacterial agents are different from the allergen-reducing agents used in the present invention.

[0089] The antiviral agent can be an inorganic antiviral agent and / or an organic antiviral agent. In general, inorganic antiviral agents are advantageous in terms of stability, which allows the antiviral effect to be maintained for a long period of time, while organic antiviral agents are advantageous in terms of rapid action, which allows the antiviral effect to be exerted in a short period of time. Therefore, they can be used depending on the expected effects of each agent. Among these antiviral agents, it is preferable to use an organic antiviral agent in the present invention because of the rapid action of the antiviral effect.

[0090] Examples of organic antiviral agents include quaternary ammonium salt-based, quaternary phosphonium salt-based, pyridine-based, pyrithione-based, benzimidazole-based, organic iodine-based, isothiazolin-based, anionic, and ether-based antiviral agents.

[0091] Among the above organic antiviral agents, at least one selected from the group consisting of benzimidazole antiviral agents, anionic antiviral agents, and ether antiviral agents, which are antiviral agents that maintain a particulate shape, is preferably used. The phrase "the antiviral agent maintains a particulate shape" means that the antiviral agent (particles) are not dissolved in the resin composition that forms the surface protective layer, and are present in the curable resin layer while maintaining a particulate shape.

[0092] The antiviral agent is different from the allergen-reducing agent used in the present invention.

[0093] (Characteristics of the surface protective layer) In the decorative sheet of the present invention, the nanoindentation hardness of the surface protective layer is preferably 80 MPa or more and 400 MPa or less, more preferably 100 MPa or more and 380 MPa or less, and even more preferably 200 MPa or more and 350 MPa or less. When the nanoindentation hardness of the surface protective layer is within the above range, the surface protective layer can combine allergen reduction performance with the surface performance of the surface protective layer (any surface performance that a surface protective layer should originally have, such as scratch resistance, impact resistance, chemical resistance, etc.).

[0094] The "nanoindentation hardness" of the surface protective layer is a value measured using a nanoindenter. Specifically, in this specification, the nanoindentation hardness is measured using a microarea mechanical property evaluation device, Triboindenter (registered trademark) "TI-950" (manufactured by Bruker). The method for measuring the indentation hardness (HIT) of the surface protective layer using the Triboindenter (registered trademark) "TI-950" is as follows. (1) A triangular pyramidal Berkovich indenter (model number: TI0039) shown in FIG. 6(a) is used as the indenter of the nanoindenter. As shown in FIG. 6(b), the Berkovich indenter is pressed into the measurement sample under the indentation conditions described below, and the indentation depth h (nm) versus the indentation load F (μN) is continuously measured, and a load-displacement curve is created as shown in FIG. 6(c). The maximum indentation load Fmax (μN) is determined from the created load-displacement curve. Next, the maximum indentation load Fmax (μN) was calculated as the contact projection area Ap (μm ２ ) to obtain the hardness. Here, Ap is the contact projected area corrected for the indenter tip curvature using a standard sample of fused quartz according to the instrument's standard method. That is, HIT = Fmax / Ap. (2) The indentation conditions are as shown in Figure 6(c) at room temperature (23±5°C), first applying a load from 0 to 50 μN for 5 seconds (i.e., 10 μN / s), then holding the load at 50 μN (Fmax) for 5 seconds, and finally unloading from 50 to 0 μN for 5 seconds. (3) Note that when measuring hardness, the hardness of the cross section of the layer being measured is measured to avoid the influence of the hardness of layers other than the layer being measured. That is, the decorative sheet is embedded in resin (a two-component epoxy resin that cures at room temperature) and left to harden for 24 hours or more at room temperature, and then the hardened embedded sample is scraped off with a sharp blade (for example, a diamond knife used for preparing electron microscope sections) so that the Berkovich indenter can be pressed into it, exposing the cross-section of the layer to be measured, and the Berkovich indenter is pressed into the cross-section of the surface protective layer (a position avoiding fine particles) to measure the hardness of the cross-section. (4) The indentation hardness of the surface protective layer is measured at 10 or more locations, and the average value of the 10 locations that are measured with good reproducibility is taken as the measured value.

[0095] The thickness of the surface protective layer is preferably 5 μm or more and 35 μm or less when the surface protective layer does not have convex portions due to the allergen-reducing agent, and if the surface protective layer has convex portions due to the allergen-reducing agent, the thickness of the smooth portion excluding the convex portions is preferably 5 μm or more and 35 μm or less. In either case, in relation to the average particle size of the allergen-reducing agent, the average particle size is preferably 2 / 3 or less of the thickness of the surface protective layer. Within the range that satisfies this condition, the thickness of the surface protective layer may be 10 μm or more and 30 μm or less.

[0096] The thickness of the surface protective layer is the average value (average thickness) measured at a flat area (thickness A in the drawing) where no protrusions (protrusions of the surface protective layer) due to the embossed uneven pattern, the allergen reduction used in the present invention, or the benzotriazole-based UV absorber are formed, and in this specification it means the average thickness of 10 arbitrary points within a width of 1 cm in an observed cross-sectional image of the surface protective layer. The "width" is the direction perpendicular to the thickness direction.

[0097] The surface protective layer may have an uneven shape formed by ridge-like protruding portions. Examples of methods for forming the ridge-like protruding portions include the following: The ionizing radiation curable resin constituting the surface protective layer is pre-cured using a UV irradiation device. The surface of the pre-cured ionizing radiation curable resin is then irradiated with excimer light having energy capable of cleaving polymer chains, causing the surface of the ionizing radiation curable resin to shrink, thereby forming ridge-like protruding portions on the surface of the surface protective layer. The shrunk ionizing radiation curable resin is then irradiated with ionizing radiation that cures the ionizing radiation curable resin, thereby curing the ionizing radiation curable resin, thereby forming an uneven shape formed by ridge-like protruding portions.

[0098] The UV irradiated from the UV irradiator in the pre-curing is preferably an LED. The excimer light preferably has a wavelength of about 120 to 230 nm. The ionizing radiation that cures the ionizing radiation-curable resin refers to electromagnetic waves or charged particles that have energy capable of polymerizing or crosslinking molecules, and is generally an electron beam (EB) or ultraviolet light (UV).

[0099] Methods for imparting a matte effect to the surface of the decorative sheet of the present invention include the above-mentioned formation of ridges, embossing, and the addition of a gloss adjuster to the surface protective layer. These methods can be used alone or in combination of two or more depending on the desired level of matte effect and surface properties such as scratch resistance.

[0100] The surface protective layer may have a two-layer structure, as shown in Figure 4, in which the cross-linked curable resin layer 7 has a first cross-linked curable resin layer 7-1 and a second cross-linked curable resin layer 7-2, and the first surface protective layer 7-1 contains an allergen reducing agent 9-1 and a triazine-based ultraviolet absorber 9-2. Even when the surface protective layer 7 has a two-layer structure, the thickness of the surface protective layer 7 refers to thickness A (the sum of the thicknesses of 7-1 and 7-2) shown in Figure 4. The two-layer structure ensures a thickness of the surface protective layer that is advantageous for scratch resistance, while facilitating the distribution of the allergen reducing agent near the outermost surface of the surface protective layer.

[0101] The surface protective layer can be formed, for example, by applying a resin composition for forming a surface protective layer containing a cross-linking curable resin component, an allergen reducing agent, and a triazine-based UV absorber onto a primer layer by a known coating method such as gravure coating or roll coating, and then curing the resin composition for forming a surface protective layer. Specifically, after applying the resin composition for forming a surface protective layer, the allergen reducing agent may lift up in the coating film before it is completely cured, resulting in the formation of convex portions due to the allergen reducing agent on the outermost surface of the surface protective layer, or the allergen reducing agent may partially aggregate in the coating film, resulting in an apparent increase in particle size of the allergen reducing agent, but this does not affect the expression of allergen reducing performance. Thus, to lift up the allergen reducing agent, it is preferable to use an allergen reducing agent with a specific gravity smaller than that of the cross-linking curable resin component constituting the surface protective layer. Furthermore, even when using an allergen reducing agent with a higher specific gravity than the cross-linked curable resin component, the proportion of allergen reducing agent present in the upper layer of the surface protective layer can be increased by dispersing it at a relatively high density on the surface of the uncured surface protective layer.

[0102] On the other hand, the surface protective layer may be formed by a transfer method. Figure 5 is a cross-sectional schematic diagram showing an example of an allergen-reduced pressure-sensitive adhesive sheet and allergen-reduced decorative board of the present invention obtained using a transfer method. In Figure 5 (I), a surface protective layer 7 and a pressure-sensitive adhesive sheet 10 are formed in this order on a release film 14. In this case, by using an allergen-reducing agent 9-1 having a larger specific gravity than the cross-linked curable resin component forming the surface protective layer, the allergen-reducing agent 9-1 can be precipitated in the cross-linked curable resin layer 7 and more easily distributed near the release film 14. Next, in Figure 5 (II), the allergen-reduced pressure-sensitive adhesive sheet 11 of the present invention obtained by peeling off the release film 14 is laminated on a decorative board substrate 12 such as a building material to produce an allergen-reduced decorative board 13.

[0103] Substrate Sheet: On the surface (front side) of the substrate sheet, a pattern layer and the like are sequentially laminated. The outermost layer is a surface protection layer.

[0104] Examples of the substrate sheet include various materials such as resin films, paper, and resin-impregnated paper, but among resin films, those containing a thermoplastic resin as a resin component are preferred. Specific examples include polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyethylene, polypropylene, polycarbonate, polyethylene naphthalate, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ionomer, acrylic acid ester, methacrylic acid ester, and the like. In the present invention, at least one of polyvinyl chloride and polyolefins (polyethylene, polypropylene, etc.) can be preferably used.

[0105] In recent years, the use of biomass-derived resins, which have a low environmental impact, has been widely investigated, and the resin forming the substrate sheet of the decorative sheet of the present invention can also contain a biomass-derived component. Specific examples of the biomass-derived component include biomass polyolefins. The substrate sheet can be formed using one of these resins alone or a mixture of two or more.

[0106] Furthermore, from the perspective of reducing the burden on the environment, the use of resins containing chemically recycled polyolefins, which are polyolefins formed by polymerizing monomers containing chemically recycled olefins, has been considered in recent years, and chemically recycled polyolefins can also be used as the resin forming the base sheet of the decorative sheet of the present invention.

[0107] The substrate sheet may be colored. For example, the thermoplastic resin can be colored by adding a colorant (pigment or dye). Examples of colorants that can be used include inorganic pigments such as titanium dioxide, carbon black, and iron oxide, and organic pigments such as phthalocyanine blue, as well as various dyes. One or more of these may be selected. The amount of colorant added may also be appropriately determined depending on the desired color tone, etc.

[0108] The substrate sheet may contain various additives, such as fillers, matting agents, foaming agents, flame retardants, lubricants, antistatic agents, antioxidants, ultraviolet absorbers, and light stabilizers, as required.

[0109] Examples of the flame retardant include inorganic ammonium phosphate, dehydrated minerals, and expandable graphite.

[0110] Examples of inorganic ammonium phosphate include ammonium polyphosphate, piperazine polyphosphate, melamine polyphosphate, ammonium amide polyphosphate, and aluminum polyphosphate.

[0111] The thickness of the substrate sheet can be appropriately set depending on the application and method of use of the final product, but is generally preferably 50 to 250 μm.

[0112] If necessary, the surface (front surface) of the substrate sheet may be subjected to a corona discharge treatment in order to improve the adhesion of the ink forming the picture pattern layer. The corona discharge treatment may be carried out by a known method and under known conditions. If necessary, the back surface of the substrate sheet may be subjected to a corona discharge treatment, a picture pattern layer (so-called back print) may be formed, or a back primer layer (described later), a backer layer (described later), or the like may be formed.

[0113] The picture pattern layer is an optional layer that imparts a desired picture (design) to the decorative sheet of the present invention, and the type of picture is not limited. Examples include wood grain, leather, stone, sand, tile, brickwork, fabric, geometric shapes, letters, symbols, abstract patterns, floral patterns, landscapes, characters, etc.

[0114] The method for forming the picture pattern layer is not particularly limited, and for example, the picture pattern layer may be formed on the surface of the substrate sheet by a known printing method using an ink obtained by dissolving (or dispersing) a known colorant (dye or pigment) together with a binder resin in a solvent (or dispersion medium). From the viewpoint of reducing VOCs in the decorative sheet, an aqueous composition may also be used as the ink.

[0115] Examples of colorants include inorganic pigments such as carbon black, titanium white, zinc white, red iron oxide, iron blue, and cadmium red; organic pigments such as azo pigments, lake pigments, anthraquinone pigments, quinacridone pigments, phthalocyanine pigments, isoindolinone pigments, and dioxazine pigments; metal powder pigments such as aluminum powder and bronze powder; pearlescent pigments such as titanium oxide-coated mica and bismuth oxide chloride; fluorescent pigments; and luminous pigments. These colorants can be used alone or in combination. These colorants may be used together with fillers such as silica, extender pigments such as organic beads, neutralizers, surfactants, and the like.

[0116] As binder resins, in addition to hydrophilically treated polyester-based urethane resins, polyesters, polyacrylates, polyvinyl acetates, polybutadiene, polyvinyl chloride, chlorinated polypropylenes, polyethylene, polystyrene, polystyrene-acrylate copolymers, rosin derivatives, alcohol adducts of styrene-maleic anhydride copolymers, cellulose-based resins, etc. can also be used. More specifically, for example, polyacrylamide-based resins, poly(meth)acrylic acid-based resins, polyethylene oxide-based resins, poly(N-vinylpyrrolidone)-based resins, water-soluble polyester-based resins, water-soluble polyamide-based resins, water-soluble amino-based resins, water-soluble phenol-based resins, other water-soluble synthetic resins, water-soluble natural polymers such as polynucleotides, polypeptides, and polysaccharides, etc. can also be used. Furthermore, for example, natural rubber, synthetic rubber, polyvinyl acetate-based resins, (meth)acrylic resins, polyvinyl chloride-based resins, polyurethane-polyacrylic resins, etc., or modified products thereof, and other resins can also be used. The above binder resins can be used alone or in combination of two or more.

[0117] Examples of the solvent (or dispersion medium) include petroleum-based organic solvents such as hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane, and methylcyclohexane; ester-based organic solvents such as ethyl acetate, butyl acetate, 2-methoxyethyl acetate, and 2-ethoxyethyl acetate; alcohol-based organic solvents such as methyl alcohol, ethyl alcohol, normal propyl alcohol, isopropyl alcohol, isobutyl alcohol, ethylene glycol, and propylene glycol; ketone-based organic solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether-based organic solvents such as diethyl ether, dioxane, and tetrahydrofuran; chlorine-based organic solvents such as dichloromethane, carbon tetrachloride, trichloroethylene, and tetrachloroethylene; and inorganic solvents such as water. These solvents (or dispersion media) can be used alone or in combination of two or more.

[0118] Furthermore, in recent years, the use of biomass-derived resins, which have a low environmental impact, has been widely studied, and resins such as the binder resin that forms the design layer of the decorative sheet of the present invention can also contain biomass-derived components. Specific examples of biomass-derived components that can be used include urethane (meth)acrylates made from biomass-derived components. Specific examples of biomass-derived resins include binder resins that contain at least a polyol, an isocyanate compound, and a urethane (meth)acrylate containing a hydroxy (meth)acrylate, and at least one selected from the group consisting of the polyol, the isocyanate compound, and the hydroxy (meth)acrylate contains a biomass-derived component.

[0119] Examples of printing methods used to form the picture pattern layer include gravure printing, offset printing, screen printing, flexographic printing, electrostatic printing, and inkjet printing. When forming a solid picture pattern layer over the entire surface, examples of coating methods include roll coating, knife coating, air knife coating, die coating, lip coating, comma coating, kiss coating, flow coating, and dip coating. Other methods that may be used include hand-drawing, ink-flowing, photography, transfer printing, laser beam writing, electron beam writing, partial vapor deposition of metals or the like, and etching, or may be used in combination with other forming methods.

[0120] The thickness of the picture pattern layer is not particularly limited and can be set appropriately depending on the product characteristics, but the layer thickness is about 0.1 to 15 μm.

[0121] Transparent Resin Layer The transparent resin layer is a layer that can be provided arbitrarily and is not particularly limited as long as it is transparent, and may be colorless and transparent, colored and transparent, translucent, or the like. The material of the transparent resin layer is not limited, but one formed from a thermoplastic resin is preferred. Specific examples include polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyethylene, polypropylene, polycarbonate, polyethylene naphthalate, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ionomer, acrylic acid ester, methacrylic acid ester, and the like. In the present invention, at least one of polyvinyl chloride and polyolefin (polyethylene, polypropylene, etc.) can be preferably used. In this specification, when the transparent resin layer contains a thermoplastic resin, the transparent resin layer is specifically referred to as a "transparent thermoplastic resin layer."

[0122] Furthermore, in recent years, the use of biomass-derived resins, which have a low environmental impact, has been widely investigated, and the resin forming the transparent resin layer (transparent thermoplastic resin layer) of the decorative sheet of the present invention can also contain a biomass-derived component. Specific examples of the biomass-derived component include biomass polyolefins. The transparent resin layer (transparent thermoplastic resin layer) can be formed by using one of these resins alone or a mixture of two or more of them.

[0123] From a similar perspective, the use of resins containing chemically recycled polyolefins, which are polyolefins formed by polymerizing monomers containing chemically recycled olefins, has also been considered in recent years, and chemically recycled polyolefins can also be used as the resin forming the transparent resin layer (transparent thermoplastic resin layer) of the decorative sheet of the present invention.

[0124] The transparent resin layer may be colored as long as it has transparency.

[0125] Furthermore, the transparent resin layer may contain various additives such as a flame retardant, a lubricant, an antistatic agent, an antioxidant, an ultraviolet absorber, and a light stabilizer, as needed, so long as it has transparency.

[0126] Examples of the flame retardant include inorganic ammonium phosphate, dehydrated minerals, and expandable graphite.

[0127] The thickness of the transparent resin layer is not limited, but is preferably 40 μm to 300 μm, more preferably 60 μm to 200 μm, and most preferably 60 μm to 100 μm. By setting the thickness of the transparent resin layer within the above range, it is possible to form a deep embossment and to easily obtain the effect of suppressing the occurrence of scratches and scraping (removal of the pattern) due to wear of the pattern layer.

[0128] Transparent Adhesive Layer A transparent adhesive layer may be formed to enhance adhesion between the picture pattern layer and the transparent resin layer or the surface protective layer. The transparent adhesive layer is not particularly limited as long as it is transparent, and may be colorless and transparent, colored and transparent, translucent, etc.

[0129] The adhesive is not particularly limited, and adhesives known in the field of decorative sheets can be used. Examples of adhesives known in the field of decorative sheets include thermoplastic resins such as polyamide resins, acrylic resins, and vinyl acetate resins, and thermosetting resins such as urethane resins. These adhesives can be used alone or in combination of two or more. Two-component curing polyurethane resins or polyester resins using isocyanate as a curing agent can also be used.

[0130] The thickness of the transparent adhesive layer is not particularly limited, but is about 0.1 to 30 μm, preferably about 1 to 20 μm.

[0131] Primer Layer A primer layer for the surface protective layer may be provided on the transparent resin layer. This primer layer not only improves the adhesion between the transparent resin layer and the surface protective layer described below, but also improves the folding processability and scratch resistance of the decorative sheet when combined with the cross-linked cured resin layer. The primer layer is not particularly limited as long as it is transparent, and may be colorless and transparent, colored and transparent, translucent, etc.

[0132] The primer layer can be formed by applying a known primer agent to the surface of the transparent resin layer. Examples of primer agents include urethane resin-based primer agents made from acrylic-modified urethane resin (acrylic urethane copolymer resin), polycarbonate-based acrylic urethane copolymer resin, etc., primer agents made from urethane-cellulose resin (e.g., a resin obtained by adding hexamethylene diisocyanate to a mixture of urethane and soluble cellulose), and resin-based primer agents made from acrylic and urethane block copolymers. Among these, urethane resin-based primer agents containing polycarbonate-based acrylic urethane copolymer resins are preferred from the viewpoints of scratch resistance and weather resistance.

[0133] The primer agent may contain additives as needed. Examples of additives include weathering agents such as ultraviolet absorbers and light stabilizers; fillers such as silica, calcium carbonate, and clay; flame retardants such as magnesium hydroxide; antioxidants; lubricants; and foaming agents. The amount of additives to be added can be appropriately determined depending on the product characteristics.

[0134] Among the above additives, examples of ultraviolet absorbers include benzophenone-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and triazine-based ultraviolet absorbers. Examples of light stabilizers that are suitable are hindered amine-based light stabilizers (HALS). The content of these weathering agents is not limited, but it is sufficient to set the content of each of the ultraviolet absorber and light stabilizer to approximately 1,000 to 100,000 ppm by mass. In particular, in the present invention, it is preferable to use a triazine-based ultraviolet absorber and / or a hindered amine-based light stabilizer.

[0135] The thickness of the primer layer is not limited, but is preferably 0.5 μm to 12 μm, more preferably 1 μm to 8 μm. By setting the thickness within this range, the combination with the cross-linked cured resin layer makes it easier to improve the folding processability and scratch resistance of the decorative sheet. In addition, it makes it easier to incorporate additives such as weathering agents, making it easier to impart weather resistance to the decorative sheet.

[0136] Embossing is performed to impart a desired texture, such as a wood grain pattern, to the decorative sheet, and embossing may be performed on the transparent resin layer and / or the surface protective layer. For example, the surface protective layer is heated and softened, then pressed and shaped with an embossing plate having a desired concave-convex pattern, and then cooled and fixed to impart the texture. Embossing can be performed using a known sheet-fed or rotary embossing machine.

[0137] Examples of embossed uneven patterns include wood grain vessel grooves, raised patterns (raised annual ring patterns), hairlines, sand grain, and matte finish.

[0138] When embossing is performed, ink may be filled into the embossed recesses by wiping, if necessary. For example, ink is filled into the embossed recesses while scratching the surface with a doctor blade. The ink to be filled (wiping ink) is usually an ink with a two-component curing urethane resin as a binder. In particular, wiping the unevenness of the wood grain vessel grooves can enhance the product value by expressing a design that is closer to the actual wood grain.

[0139] Backside Primer Layer If necessary, a backside primer layer may be provided on the backside of the base sheet. This is effective, for example, when bonding the base sheet to a decorative board substrate to produce a decorative board.

[0140] The back primer layer can be formed by applying a known primer agent to the substrate sheet. Examples of primer agents include urethane resin-based primer agents made from acrylic-modified urethane resin (acrylic urethane copolymer resin), polycarbonate-based acrylic urethane copolymer resin, etc., primer agents made from urethane-cellulose resin (e.g., a resin obtained by adding hexamethylene diisocyanate to a mixture of urethane and soluble nitrocellulose), and resin-based primer agents made from an acrylic-urethane block copolymer.

[0141] The primer agent may contain additives as needed. Examples of additives include fillers such as calcium carbonate and clay, flame retardants such as magnesium hydroxide, antioxidants, lubricants, foaming agents, ultraviolet absorbers, and light stabilizers. The amount of additives added can be appropriately determined depending on the product characteristics.

[0142] The thickness of the back primer layer is not particularly limited, but is usually about 0.01 to 10 μm, preferably about 0.1 to 1 μm.

[0143] Synthetic Resin Backer Layer A synthetic resin backer layer may be provided on the back surface of the substrate sheet, if necessary. By providing a synthetic resin backer layer, the impact resistance of the decorative sheet is further improved. When the above-mentioned back primer layer is also provided, the synthetic resin backer layer and back primer layer are provided on the back surface of the substrate sheet in this order from the substrate sheet side.

[0144] Examples of resins that can be used to form the synthetic resin backer layer include polypropylene, ethylene-vinyl alcohol copolymer, polymethylene, polymethylpentene, polyethylene terephthalate, highly heat-resistant polyalkylene terephthalate (for example, polyethylene terephthalate in which part of the ethylene glycol has been substituted with 1,4-cyclohexanedimethanol, diethylene glycol, or the like, known as PET-G (manufactured by Eastman Chemical Company)), polybutylene terephthalate, polyethylene naphthalate, polyethylene naphthalate-isophthalate copolymer, polycarbonate, polyarylate, polyimide, polystyrene, polyamide, ABS, diene rubbers such as styrene-butadiene rubber, isoprene rubber, and chloroprene rubber, non-diene rubbers such as butyl rubber and ethylene-propylene rubber, natural rubber, and thermoplastic elastomers. These resins can be used alone or in combination of two or more.

[0145] The synthetic resin backing layer may contain a flame retardant.

[0146] Examples of the flame retardant include inorganic ammonium phosphate, dehydrated minerals, and expandable graphite.

[0147] The thickness of the synthetic resin backer layer is preferably 0.1 to 0.6 mm, more preferably 0.15 to 0.45 mm, and even more preferably 0.20 to 0.40 mm. By setting the lower limit of the thickness of the synthetic resin backer layer within the above range, the impact resistance of the decorative sheet is further improved. Furthermore, by setting the upper limit of the thickness of the synthetic resin backer layer within the above range, warping of the decorative sheet is further suppressed.

[0148] Vesiculation of Various Additives Included in Each Layer of the Decorative Sheet The various additives added to the above-mentioned layers of the decorative sheet of the present invention (such as additives added to the primer layer or surface protective layer) are preferably vesiculated. The method for vesiculating the various additives is not particularly limited, and they can be vesiculated by any known method, with supercritical reverse phase evaporation being particularly preferred.

[0149] In addition to supercritical reverse-phase evaporation, other vesicle-forming methods include the Bangham method, extrusion, hydration, reverse-phase evaporation, and freeze-thawing. Briefly, the Bangham method involves placing chloroform or a chloroform / methanol mixed solvent in a container such as a flask, followed by dissolving phospholipids. The solvent is then removed using an evaporator to form a thin lipid film, and a dispersion of additives is added. The resulting solution is then hydrated and dispersed in a vortex mixer to obtain vesicles. The extrusion method involves preparing a thin phospholipid solution and passing it through a filter, replacing the mixer used as an external perturbation in the Bangham method, to obtain vesicles. The hydration method is a preparation method similar to the Bangham method, but does not use a mixer; instead, vesicles are obtained by gently stirring and dispersing the solution. The reverse phase evaporation method involves dissolving phospholipids in diethyl ether or chloroform, adding a solution containing an additive to form a W / O emulsion, removing the organic solvent from the emulsion under reduced pressure, and then adding water to obtain vesicles.The freeze-thaw method uses cooling and heating as external perturbations, and obtains vesicles by repeating this cooling and heating process.

[0150] Supercritical reverse-phase evaporation is described in detail below. Supercritical reverse-phase evaporation is a method in which a substance forming the outer membrane of a vesicle is uniformly dissolved in carbon dioxide in a supercritical state or at a temperature or pressure above the supercritical point, and an aqueous phase containing various additives as water-soluble or hydrophilic encapsulation substances is added to the mixture to form a capsule-like vesicle encapsulating the various additives as encapsulation substances in a single layer. Carbon dioxide in a supercritical state refers to carbon dioxide in a supercritical state at or above its critical temperature (30.98°C) and critical pressure (7.3773±0.0030 MPa). Carbon dioxide under a temperature or pressure above its critical point refers to carbon dioxide under conditions in which only the critical temperature or only the critical pressure exceeds the critical conditions. This method can produce unilamellar vesicles with a diameter of 50 to 800 nm. Generally, a vesicle is a general term for a small vesicle having a spherical, closed membrane structure and containing a liquid phase inside, and in particular, a liposome is one whose outer membrane is composed of biological lipids such as phospholipids.

[0151] Examples of the phospholipids include glycerophospholipids such as phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidic acid, phosphatidylglycerol, phosphatidylinositol, cardiolipin, egg yolk lecithin, hydrogenated egg yolk lecithin, soybean lecithin, and hydrogenated soybean lecithin; and sphingophospholipids such as sphingomyelin, ceramide phosphorylethanolamine, and ceramide phosphorylglycerol.

[0152] The substance that can be used to form the outer membrane may also be a dispersant such as a nonionic surfactant or a mixture of a nonionic surfactant with cholesterol or triacylglycerol.

[0153] As the nonionic surfactant, one or more of polyglycerin ether, dialkylglycerin, polyoxyethylene hydrogenated castor oil, polyoxyethylene alkyl ether, polyoxyethylene sorbitan fatty acid ester, sorbitan fatty acid ester, polyoxyethylene polyoxypropylene copolymer, polybutadiene-polyoxyethylene copolymer, polybutadiene-poly2-vinylpyridine, polystyrene-polyacrylic acid copolymer, polyethylene oxide-polyethylethylene copolymer, polyoxyethylene-polycaprolactam copolymer, etc. can be used.

[0154] As the cholesterols, one or more of cholesterol, α-cholestanol, β-cholestanol, cholestane, desmosterol (5,24-cholestadien-3β-ol), sodium cholate, cholecalciferol, and the like can be used.

[0155] The outer membrane of the liposome may be formed from a mixture of a phospholipid and a dispersant. In the decorative sheet of the present invention, by using a liposome whose outer membrane is formed from a phospholipid, it is possible to improve the compatibility between the resin composition, which is the main component of each layer, and various additives.

[0156] 2. Allergen-reduced adhesive sheet The allergen-reduced adhesive sheet of the present invention (hereinafter also referred to simply as "adhesive sheet") is composed of a laminate comprising, in order in the thickness direction, at least an adhesive sheet and the allergen-reduced decorative sheet of the present invention. There are no particular limitations on the adhesive sheet, and adhesive sheets used in the fields of decorative sheets and other functional sheets can be used as appropriate. By having an adhesive sheet on its back side, the adhesive sheet of the present invention can be attached to the surface of various flooring articles and adherends, and can be imparted with allergen-reducing properties as desired.

[0157] Figure 2 shows an example of an allergen-reduced adhesive-processed sheet 11 in which the decorative sheet 1 of the present invention (the adhesive sheet 10 is attached to the side opposite the surface protective layer) is laminated in this order on an adhesive sheet 10.

[0158] 3. Allergen-Reduced Decorative Board The allergen-reduced decorative board of the present invention (hereinafter also referred to simply as "decorative board") is composed of a laminate comprising, in order in the thickness direction, at least a decorative board substrate and the decorative sheet of the present invention or the pressure-sensitive adhesive sheet of the present invention.

[0159] FIG. 3 shows an example of an allergen-reduced decorative board 13 in which the decorative sheet 1 of the present invention (the side opposite the surface protective layer side and the decorative board substrate 12 are bonded together) is laminated in this order on the decorative board substrate 12.

[0160] The decorative board substrate is not limited, and examples thereof include at least one of medium-density wood fiberboard, high-density wood fiberboard, particle board, softwood plywood, hardwood plywood, fast-growing tree plywood, cork sheet, cork-containing composite substrate, thermoplastic resin board (a resin board mainly composed of polyvinyl chloride resin, polypropylene resin, polyethylene resin, acrylic resin, ABS resin, etc., or a foamed version thereof), etc. These decorative board substrates may be used alone or in combination of two or more types, which may be laminated.

[0161] Here, examples of coniferous trees include linden pine, larch, Hokkaido pine, cedar, cypress, pine, sequoia, spruce, etc. Examples of broad-leaved trees include lauan, china, birch, sen, beech, oak, meranti, etc. Furthermore, examples of fast-growing trees include poplar, falcata, acacia, camellia, eucalyptus, terminalia, etc.

[0162] When using wood plywood such as softwood plywood, hardwood plywood, or fast-growing wood plywood, the number of layers of wood veneers (number of plies) is not limited, but typically 3 to 7 plies is preferred, and 5 to 7 plies is more preferred. The adhesive used in producing the wood plywood is also not limited, and a wide variety of known woodworking adhesives can be used. Examples of adhesives include those containing polyvinyl acetate, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ionomer, butadiene-acrylonitrile rubber, neoprene rubber, and natural rubber as active ingredients. Examples of thermosetting adhesives include melamine-based, phenol-based, and urea-based (e.g., vinyl acetate-urea-based) adhesives.

[0163] The cork sheet can be made of so-called natural cork, which is a highly elastic material made by peeling and processing the cork tissue from the bark of the cork oak, or a so-called synthetic cork made to resemble cork. The cork sheet can be a single layer or a laminate of multiple cork sheets with different elastic moduli and densities.

[0164] Examples of the cork-containing composite substrate include composite materials formed by laminating and bonding a cork sheet with another material (for example, a medium-density wood fiber board or a high-density wood fiber board).

[0165] The thickness of the decorative board substrate is not limited, but is preferably about 2 to 15 mm, and more preferably about 2 to 12 mm.

[0166] The lamination method for laminating the decorative sheet or pressure-sensitive adhesive sheet and the decorative board substrate is not limited, and can be, for example, a method of adhering them with an adhesive. Furthermore, if the pressure-sensitive adhesive sheet has sufficient adhesion to the decorative board substrate, a method of adhering the pressure-sensitive adhesive sheet and the decorative board substrate without the use of an adhesive can be employed. The adhesive can be appropriately selected from known adhesives depending on the type of adherend, etc. Examples include urethane, acrylic, urethane-acrylic, polyvinyl acetate, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ionomer, etc., as well as butadiene-acrylonitrile rubber, neoprene rubber, natural rubber, etc. These adhesives can be used alone or in combination of two or more.

[0167] The present invention will be specifically explained below with reference to examples, comparative examples and test examples, but the present invention is not limited to the contents shown in the examples.

[0168] Example 1 A resin composition for forming a transparent resin layer was prepared by blending 100 parts by mass of a highly crystalline homopolypropylene resin (Novatec PP, product name FY4, manufactured by Mitsubishi Chemical Corporation) with 0.5 parts by mass of a hindered phenol-based antioxidant (Irganox 1010, manufactured by BASF), 0.5 parts by mass of a triazine-based ultraviolet absorber (CYASORBUV-1164, manufactured by SUNCHEM), and 0.5 parts by mass of a NOR-type light stabilizer (Tinuvin 622SF, manufactured by BASF). The resin composition for forming a transparent resin layer was melt-extruded using an extruder to form a sheet-like transparent resin layer, which was a transparent, highly crystalline polypropylene sheet having a thickness of 60 μm. Next, both sides of the obtained transparent resin layer were subjected to a corona treatment.

[0169] A pattern of concave and convex shapes was formed on the surface of the transparent resin layer by hot-press embossing. The decorative sheet of Example 1 was produced by sequentially coating a composition containing a thermosetting resin (hereinafter referred to as a thermosetting resin composition; coating amount after drying (described as film thickness after drying; the same applies hereinafter) 5 μm) and a photocurable composition (resin composition for forming a surface protective layer) as a surface protective layer (coating amount after drying 10 μm) using the resin composition for forming a surface protective layer described below.

[0170] <Thermosetting composition> Polyol solution A: 80 parts by mass 80 g of methyl methacrylate and 20 g of 2-hydroxyethyl methacrylate were introduced into a four-necked flask equipped with a stirrer, a nitrogen inlet tube, and a reflux condenser, and 100 g of ethyl acetate was added to dissolve the mixture, followed by stirring in a nitrogen atmosphere on an oil bath. 0.2 g of α,α'-azobisisobutyronitrile was added to initiate polymerization, and the mixture was heated and stirred for 5 hours on a 60°C oil bath to obtain a colorless, viscous polyol solution A. Curing agent: 5.0 parts by mass, hydrogenated MDI (hydrogenated diphenylmethane diisocyanate, manufactured by Evonik) Dilution solvent: 50 parts by mass, ethyl acetate

[0171] <Photocurable composition (ultraviolet-curable resin composition)> Ultraviolet-curable resin (UV resin): 90 parts by mass, trade name: UA-33H (manufactured by Shin-Nakamura Chemical Co., Ltd.), properties: molecular weight 1400, number of functional groups 9 Photoinitiator: 8 parts by mass, trade name: Irgacure 184 (manufactured by BASF) Allergen denaturing agent: 5 parts by mass, phenolic polymer, trade name: Marukalinker M (manufactured by Maruzen Petrochemical Co., Ltd.), average particle size 3 μm Ultraviolet absorber A: 2 parts by mass, benzotriazole-based ultraviolet absorber, trade name: Tinuvin 326 (manufactured by BASF) Ultraviolet absorber B: 2 parts by mass, benzotriazole-based ultraviolet absorber, trade name: Tinuvin P (manufactured by BASF) Light stabilizer: 2.0 parts by mass, trade name: Sanol LS765 (manufactured by BASF) Dilution solvent: 60 parts by mass, ethyl acetate

[0172] Comparative Example 1 A decorative sheet was obtained in the same manner as in Example 1, except that the ultraviolet absorbers were changed as follows: Ultraviolet absorber A: 2 parts by mass, benzophenone-based ultraviolet absorber, trade name: Chimassorb 81 (manufactured by BASF) Ultraviolet absorber B: 2 parts by mass, benzophenone-based ultraviolet absorber, trade name: KEMISORB 12 (manufactured by Chemipro Chemical Co., Ltd.)

[0173]

[0046] Fabrication of decorative boards

[0047] Decorative boards were fabricated using the decorative sheets fabricated in the examples and comparative examples. Specifically, a water-based emulsion adhesive (manufactured by Japan Coating Resin Co., Ltd., BA-10L (main agent):BA-11B (hardener) = 100:2.5 (mass ratio)) was applied at 80 g / m onto a 2.5 mm thick medium density wood fiberboard (MDF). ２ The mixture was applied uniformly to the back primer layer side of the decorative sheet, and then cured at room temperature for 3 days to prepare a decorative floor board.

[0174] (Evaluation Method) The following evaluations were carried out for the Examples and Comparative Examples.

[0175] <Allergen Reduction Performance (Initial Allergen Reduction Performance)> The inactivation rate of mite allergens for the decorative panels produced in the Examples and Comparative Examples was measured using an ITEA mite allergen (Der f 1) ELISA kit (manufactured by ITEA Corporation). Specifically, a mite allergen solution was prepared by adjusting the initial concentration of the mite allergen standard solution included in the kit to 100 ng / ml using a dilution solution. Then, 5 cm ２ 400 μl of the prepared mite allergen solution was dropped onto the test piece cut into 5 cm ２ The test specimen was covered with a PE film and left for 24 hours, after which the mite allergens on the specimen were collected and the inactivation rate of the mite allergens was measured using the ELISA method. The allergen inactivation rate was calculated by measuring the absorbance of the initial allergen amount and the amount of allergen after collection and using the following formula: (Allergen inactivation rate) = (1 - (amount of remaining allergen / initial allergen amount)) x 100 (%) The allergen reduction performance was evaluated according to the following evaluation criteria.

[0176] Evaluation criteria for allergen reduction performance ++: Inactivation rate of mite allergens from the initial concentration is 90% or more +: Inactivation rate of mite allergens from the initial concentration is 70% or more but less than 90% -: Inactivation rate of mite allergens from the initial concentration is less than 70%

[0177] <Long-term durability of allergen reduction performance> The decorative panels produced in the Examples and Comparative Examples were subjected to an accelerated weathering test using the following ultra-accelerated weathering tester at a black panel temperature of 63°C and an illuminance of 100 mW / cm. ２ After 300 hours had passed, the allergen-reducing performance of the decorative sheet was evaluated using the same method as the above-mentioned method for evaluating allergen-reducing performance, and the long-term sustainability of the allergen-reducing performance was evaluated.

[0178] (Ultra-accelerated weathering test equipment) Ultra-accelerated weathering test equipment (product name: i Super UV Tester SUV-W161, manufactured by Iwasaki Electric Co., Ltd.) equipped with a UV lamp (product name: M04-L21WB / SUV, manufactured by Iwasaki Electric Co., Ltd.), a lamp jacket (product name: WJ50-SUV, manufactured by Iwasaki Electric Co., Ltd.), and an illuminance meter (product name: UVD-365PD, manufactured by Iwasaki Electric Co., Ltd.).

[0179] <Nanoindentation Hardness of Surface Protective Layer> The "nanoindentation hardness" of the surface protective layer was measured using a nanoindenter. Specifically, the nanoindentation hardness was measured using a microarea mechanical property evaluation device, Triboindenter (registered trademark) "TI-950" (manufactured by Bruker), according to the following measurement method. (1) A triangular pyramidal Berkovich indenter (model number: TI0039) shown in FIG. 6(a) was used as the indenter of the nanoindenter. As shown in FIG. 6(b), the Berkovich indenter was pressed into the measurement sample under the indentation conditions described below, and the indentation depth h (nm) versus the indentation load F (μN) was continuously measured, and a load-displacement curve was created as shown in FIG. 6(c). The maximum indentation load Fmax (μN) was calculated from the created load-displacement curve. Next, the maximum indentation load Fmax (μN) was calculated as the contact projected area Ap (μm) of the indenter and the sample at that time. ２) to determine the hardness. Here, Ap is the contact projected area corrected for the indenter tip curvature using a standard sample of fused quartz according to the instrument's standard method. That is, HIT = Fmax / Ap. (2) The indentation conditions were as shown in Figure 6(c) at room temperature (23±5°C), first applying a load from 0 to 50 μN for 5 seconds (i.e., 10 μN / s), then holding the load at 50 μN (Fmax) for 5 seconds, and finally unloading from 50 to 0 μN for 5 seconds. (3) Note that when measuring hardness, the hardness of the cross section of the layer being measured was measured to avoid the influence of the hardness of layers other than the layer being measured. That is, the decorative sheet was embedded in resin (a two-component epoxy resin that cures at room temperature) and left to harden for 24 hours or more at room temperature, and then the hardened embedded sample was scraped off with a sharp blade (for example, a diamond knife used for preparing electron microscope sections) so that the Berkovich indenter could be pressed into it, exposing the cross-section of the layer to be measured, and the Berkovich indenter was pressed into the cross-section of the surface protective layer (a position avoiding fine particles) to measure the hardness of the cross-section. (4) The indentation hardness of the surface protective layer was measured at 10 or more points, and the average value of the 10 points that were measured with good reproducibility was taken as the measured value.

[0180] The results are shown in Table 1 below.

[0181] Example 2 A decorative sheet was produced in the same manner as in Example 1, except that the content of the allergen-reducing agent contained in the surface protective layer was changed to 10 parts by mass.

[0182] Example 3 A decorative sheet was produced in the same manner as in Example 1, except that the amount of the allergen denaturing agent contained in the surface protective layer was changed to 20 parts by mass.

[0183] Example 4 A decorative sheet was produced in the same manner as in Example 1, except that the following ultraviolet absorber C was added in addition to the ultraviolet absorbers A and B contained in the surface protective layer: Ultraviolet absorber C: 2 parts by mass, benzotriazole-based ultraviolet absorber, product name: Tinuvin 329 (manufactured by BASF)

[0184] (Evaluation Method) For Examples 1 to 4 and Comparative Example 1, the allergen-reducing performance (initial allergen-reducing performance) and long-term sustainability of allergen-reducing performance were evaluated using the evaluation method described above.

[0185] Furthermore, Examples 1 to 4 and Comparative Example 1 were evaluated as follows.

[0186] <Appearance after moist heat resistance test> A decorative sheet was left in a thermo-hygrostat chamber at a temperature of 60°C and a humidity of 90% for one month to conduct a moist heat resistance test. The appearance of the decorative sheet after the moist heat resistance test was visually observed and rated according to the following evaluation criteria: +++: No change in appearance ++: Very slight cloudiness was observed, but it was not noticeable unless observed carefully and was at a level that would not cause any problems in practical use +: Slight cloudiness was observed, but it was not noticeable unless observed carefully and was at a level that would cause any problems in practical use -: Cloudiness was observed and was at a level that would cause problems in practical use

[0187] The results are shown in Table 2.

[0188] (Example 5) A primer layer (back primer layer) was formed on the back surface of a 70 μm thick base sheet (biomass degree 75) containing biomass-derived polypropylene. Next, a picture pattern layer was formed on the surface of the base sheet by printing, and an adhesive layer was further formed on the picture pattern layer. An 80 μm thick sheet containing biomass-derived polypropylene and random polypropylene resin was laminated on the adhesive layer by extrusion lamination to form a transparent resin layer. A concave-convex pattern was applied to the surface of the transparent resin layer by hot-press embossing.

[0189] Next, the following resin composition 1 for forming a surface protective layer was prepared, and a composition containing a thermosetting resin (hereinafter also referred to as a thermosetting resin composition) was applied in a coating amount after drying (described as the film thickness after drying; the same applies hereinafter) of 5 μm to form surface protective layer 1. Next, resin composition 2 for forming a surface protective layer was prepared, and applied to the surface of surface protective layer 1 in a coating amount after drying of 10 μm to form surface protective layer 2, and the decorative sheet of Example 4 was produced.

[0190] <Resin Composition 1 for Forming Surface Protection Layer (Thermosetting Resin Composition)> Polyol Solution A: 80 parts by mass 80 g of methyl methacrylate and 20 g of 2-hydroxyethyl methacrylate were introduced into a four-necked flask equipped with a stirrer, a nitrogen inlet tube, and a reflux condenser, and 100 g of ethyl acetate was added to dissolve the mixture, followed by stirring in an oil bath under a nitrogen atmosphere. 0.2 g of α,α'-azobisisobutyronitrile was added to initiate polymerization, and the mixture was heated and stirred for 5 hours in a 60°C oil bath to obtain a colorless, viscous polyol solution A. Curing agent: 5.0 parts by mass, hydrogenated MDI (hydrogenated diphenylmethane diisocyanate, manufactured by Evonik) Dilution solvent: 50 parts by mass, ethyl acetate

[0191] <Resin composition 2 for forming surface protective layer> The following resins were blended in a mass ratio of A:B:C = 60:30:10 to prepare a mixed resin. The following light stabilizer, photopolymerization initiator, and additives were added in the following amounts to 100 parts by mass of the mixed resin to prepare resin composition 2 for forming surface protective layer. Resin A: polyfunctional urethane acrylate oligomer having 3 to 15 functional groups Resin B: biomass-derived glycerin diacrylate A (molecular weight: 348, manufactured by Toagosei Co., Ltd., trade name "Aronix M-930") Resin C: 100 parts by mass of acrylic polyol having a glass transition temperature of approximately 100°C, a weight average molecular weight Mw of approximately 50,000, and a hydroxyl value of 15, and 5 parts by mass of curing agent Duranate TAP-100 (manufactured by Asahi Kasei Corporation) Ultraviolet absorber A: 2 parts by mass, benzotriazole-based ultraviolet absorber, trade name: Tinuvin 326 (manufactured by BASF Corporation) Ultraviolet absorber B: 2 parts by mass, benzotriazole-based ultraviolet absorber, trade name: Tinuvin P (manufactured by BASF Corporation) Light stabilizer: 3 parts by mass of Sanol LS765 (manufactured by BASF Corporation) Photopolymerization initiator: Irgacure 907 (manufactured by BASF Corporation) 2.5 parts by mass Photopolymerization initiator: Irgacure 184 (manufactured by BASF Corporation) 2.5 parts by mass (additive) Dilution solvent: ethyl acetate 50 parts by mass Allergen reducing agent: 5 parts by mass, phenolic polymer, trade name: Marukalinker M (manufactured by Maruzen Petrochemical Co., Ltd.), average particle size 3 μm

[0192] (Evaluation Method) For Example 5, the allergen-reducing performance (initial allergen-reducing ability) and long-term sustainability of allergen-reducing ability were evaluated using the evaluation method described above.

[0193] The results are shown in Table 3.

[0194] 1. Allergen-reduced decorative sheet 2. Base sheet 3. Picture pattern layer 4. Transparent adhesive layer 5. Transparent resin layer 6. Primer layer 7. Surface protective layer 7-1. First cross-linked curable resin layer 7-2. Second cross-linked curable resin layer 8. Back primer layer 9-1. Allergen reducing agent 9-2. Benzotriazole-based ultraviolet absorber 10. Adhesive sheet 11. Allergen-reduced adhesive-processed sheet 12. Decorative board substrate 13. Allergen-reduced decorative board 14. Release film A. Thickness of cross-linked curable resin layer (surface protective layer)

Claims

1. An allergen-reduced decorative sheet having at least a surface protective layer, characterized in that: (1) the surface protective layer contains a cured product of a cross-linking curable resin component and an allergen reducing agent; (2) the allergen reducing agent contains a phenolic polymer; and (3) the surface protective layer further contains at least two or more types of ultraviolet absorbers having a benzotriazole skeleton.

2. An allergen-reducing decorative sheet as described in claim 1, wherein the content of the allergen-reducing agent in the surface protective layer is 1 part by mass or more and less than 15 parts by mass, based on 100 parts by mass of the cured product of the cross-linked curable resin component.

3. The allergen-reduced decorative sheet according to claim 1, wherein the average particle size of the allergen-reducing agent is 1 μm or more and 15 μm or less.

4. The allergen-reduced decorative sheet according to claim 1, wherein the at least two or more ultraviolet absorbers having a benzotriazole skeleton exhibit different maximum absorption wavelengths.

5. The allergen-reduced decorative sheet according to claim 1, wherein the ultraviolet absorber contains an ultraviolet absorber with a maximum absorption wavelength of less than 350 nm and an ultraviolet absorber with a maximum absorption wavelength of 350 nm or more.

6. The allergen-reduced decorative sheet according to claim 1, wherein the ultraviolet absorber contains an ultraviolet absorber with a molecular weight of less than 300 and an ultraviolet absorber with a molecular weight of 300 or more.

7. The ultraviolet absorber is represented by the following formula (1): (In the formula, R １ and R ２ The allergen-reduced decorative sheet according to claim 1, wherein the ultraviolet absorber is represented by the formula:

8. An allergen-reduced decorative sheet as described in claim 1, wherein the content of the ultraviolet absorber in the surface protective layer is 0.5 parts by mass or more and 10 parts by mass or less, based on 100 parts by mass of the cured product of the cross-linked curable resin component.

9. The allergen-reduced decorative sheet according to claim 1, wherein the cross-linking curable resin component is an ionizing radiation curable resin component or a thermosetting resin component.

10. An allergen-reduced decorative sheet as described in claim 1, wherein the surface protective layer contains an isocyanate component, and the isocyanate component is at least one selected from the group consisting of hexamethylene diisocyanate, isophorone diisocyanate, and hydrogenated diphenylmethane diisocyanate (MDI).

11. The allergen-reduced decorative sheet according to claim 1, wherein the surface protective layer contains a polyhydric alcohol, and the polyhydric alcohol includes 2,2,4-trimethyl-1,3-pentanediol.

12. The allergen-reduced decorative sheet according to claim 1, wherein the surface protective layer contains an acrylic polyol component, and the acrylic polyol component is at least one selected from the group consisting of methyl methacrylate (MMA), methacrylic acid, hydroxyethyl acrylate (HEA), and hydroxyethyl methacrylate (HEMA).

13. The allergen-reduced decorative sheet according to claim 1, wherein the nanoindentation hardness of the surface protective layer is 80 MPa or more and 400 MPa or less.

14. An allergen-reduced decorative sheet as described in claim 1, which is composed of a laminate having at least a base sheet, a patterned layer, a transparent thermoplastic resin layer, and the surface protective layer, in that order in the thickness direction.

15. The allergen-reduced decorative sheet according to claim 14, wherein at least one of the base sheet, the pattern layer, the transparent thermoplastic resin layer, and the surface protective layer contains a biomass-derived component.

16. An allergen-reduced decorative sheet as described in claim 14, wherein the base sheet and at least one of the transparent thermoplastic resin layers contain chemically recycled polyolefin, which is a polyolefin obtained by polymerizing a monomer containing chemically recycled olefin.

17. An allergen-reduced adhesive-processed sheet comprising a laminate comprising, in order in the thickness direction, at least an adhesive sheet and the allergen-reduced decorative sheet according to claim 1.

18. An allergen-reduced decorative board comprising a laminate comprising, in order in the thickness direction, at least a decorative board substrate and the allergen-reduced decorative sheet according to claim 1.

19. An allergen-reduced decorative panel comprising a laminate comprising, in order in the thickness direction, a decorative panel substrate and the allergen-reduced adhesive sheet according to claim 17.

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