EP4592076A1

EP4592076A1 - Decorative sheet and resin-impregnated decorative panel

Info

Publication number: EP4592076A1
Application number: EP23868204.1A
Authority: EP
Inventors: Keisuke TSURUTA; Miyuki NISHINE
Original assignee: Dai Nippon Printing Co Ltd
Current assignee: Dai Nippon Printing Co Ltd
Priority date: 2022-09-20
Filing date: 2023-09-20
Publication date: 2025-07-30
Also published as: WO2024063083A1; TWI883550B; JP2024045069A; TW202417212A; CN119604411A; EP4592076A4

Abstract

The present disclosure provides a decorative sheet used for a production of a resin-impregnated decorative plate, the decorative sheet comprising: a porous substrate; a white solid layer disposed on an entire surface of one surface of the porous substrate, and including a white pigment; a pattern layer disposed partially on a surface of the white solid layer that is opposite side to the porous substrate; and a releasing layer disposed in a pattern on a surface of the pattern layer that is opposite side to the white solid layer, wherein the white solid layer includes a white blank region not covered with the pattern layer; an L* value of the white blank region is 93.0 or more; and an ash content included in the decorative sheet is 20.0% by mass or more and 40.0% by mass or less.

Description

Technical Field

The present disclosure relates to a decorative sheet used for a production of a resin-impregnated decorative plate and a resin-impregnated decorative plate.

Background Art

Resin-impregnated decorative plates obtained by impregnating precursor (uncured resin) such as melamine resin into porous substrates, and then, curing the resin precursor, are conventionally known. The resin-impregnated decorative plates are used for, for example, walls, furniture, and floors of houses, shops, and public facilities. In particular, white basic tone designs such as marble have a high demand, and white substrates are generally used to express white designs.
Melamine decorative plates expressing gloss matte tone designs are known. For example, Patent Document 1 discloses a decorative plate comprising a releasing layer in a part of a surface of a porous substrate; in a remaining region of the surface of the porous substrate where no releasing layer is disposed, a thermosetting resin layer is included, and the thermosetting resin impregnated into the porous substrate is cured; the porous substrate is a fibrous substrate; and a height difference between the thermosetting resin layer and the releasing layer is 5 µm or more.

Citation List

Patent Document

Patent Document 1: Japanese Patent No. 6716877

Summary of Disclosure

Technical Problem

Patent Document 1 discloses that, according to the method described therein, the surface of the decorative plate can express a clear gloss matte tone design since the thermosetting resin layer expresses a gloss tone design and the releasing layer expresses a matte tone design; or the thermosetting resin layer expressed a matte tone design and the releasing layer expressed a gloss tone design. By employing white porous substrates, white resin-impregnated decorative plates having gloss matte designs, which cannot be conventionally expressed, are expected to be provided.
However, white porous substrates such as titanium paper generally include white pigments such as titanium oxide, so there are many gaps between the paper, and the ink of the releasing layer, that is responsible for the expression of the gloss matte design, penetrates into the porous substrate, making it difficult to develop the gloss matte design. Meanwhile, with porous substrates that can fully exhibit the functions of the releasing layer, the content of the white pigments is not sufficient so that white designs cannot be expressed. Therefore, with the conventional decorative sheet for a production of a resin-impregnated decorative plate, it has been difficult to obtain a resin-impregnated decorative plate that can exhibit a gloss matte design stably while expressing a white design.
The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a decorative sheet capable of obtaining a resin-impregnated decorative plate that can stably exhibit a gloss matte design while expressing a white design.

Solution to Problem

The present disclosure provides a decorative sheet used for a production of a resin-impregnated decorative plate, the decorative sheet comprising: a porous substrate; a white solid layer disposed on an entire surface of one surface of the porous substrate, and including a white pigment; a pattern layer disposed partially on a surface of the white solid layer that is opposite side to the porous substrate; and a releasing layer disposed in a pattern on a surface of the pattern layer that is opposite side to the white solid layer, wherein the white solid layer includes a white blank region not covered with the pattern layer; an L* value of the white blank region is 93.0 or more; and an ash content included in the decorative sheet is 20.0% by mass or more and 40.0% by mass or less.
Also, the present disclosure provides a resin-impregnated decorative plate comprising: the decorative sheet described above; a core substrate disposed so as to face the porous substrate of the decorative sheet; and a cured resin layer disposed on the white blank region, and including a cured product of curable resin Y, wherein the core substrate and the porous substrate include the cured product of the curable resin Y; and the L* value of the white blank region is 88.0 or more, when measured via the cured resin layer.

Advantageous Effects of Disclosure

The present disclosure exhibits an effect that it is possible to provide a decorative sheet capable of obtaining a resin-impregnated decorative plate that can stably exhibit a gloss matte design while expressing a white design.

Brief Description of Drawings

[FIG. 1] is a schematic cross-sectional view exemplifying a decorative sheet in the present disclosure.
[FIG. 2] is a schematic cross-sectional view exemplifying a resin-impregnated decorative plate in the present disclosure.
[FIGS. 3] are schematic cross-sectional views exemplifying a method for producing a resin-impregnated decorative plate, using a decorative sheet in the present disclosure.
[FIGS. 4] are schematic views of a container and a lid used in the impregnation property evaluation in Examples.
[FIGS. 5] are views explaining a method for evaluating an impregnation property in Examples.
[FIGS. 6] are schematic planar views exemplifying a white solid layer in the present disclosure.

Description of Embodiments

Embodiments are hereinafter explained with reference to, for example, drawings. However, the present disclosure is implemented in a variety of different forms, and thus should not be taken as is limited to the contents described in the embodiments exemplified as below. Also, the drawings may show the features of the present disclosure such as width, thickness, and shape of each part schematically comparing to the actual form in order to explain the present disclosure more clearly in some cases; however, it is merely an example, and thus does not limit the interpretation of the present disclosure.
In the present descriptions, in expressing an aspect wherein some member is placed on the other member, when described as merely "above" or "below", unless otherwise stated, it includes both of the following cases: a case wherein some member is placed directly on or directly below the other member so as to be in contact with the other member, and a case wherein some member is placed on the upper side or the lower side of the other member via yet another member. Also, in the present descriptions, on the occasion of expressing an aspect wherein some member is placed on the surface of the other member, when described as merely "on the surface", unless otherwise stated, it includes both of the following cases: a case wherein some member is placed directly on or directly below the other member so as to be in contact with the other member, and a case wherein some member is placed on the upper side or the lower side of the other member via yet another member.

A. Decorative sheet

The decorative sheet in the present disclosure will be hereinafter described in detail. FIG. 1 is a schematic cross-sectional view exemplifying the decorative sheet in the present disclosure. The decorative sheet 10 shown in FIG. 1 comprises: a porous substrate 1; a white solid layer 2 disposed on an entire surface of one surface of the porous substrate 1, and including a white pigment; a pattern layer 3 disposed partially on a surface of the white solid layer 2 that is opposite side to the porous substrate 1; and a releasing layer 4 disposed in a pattern on a surface of the pattern layer 3 that is opposite side to the white solid layer 2. In the present disclosure, the white solid layer 2 includes a white blank region X that is not covered with the pattern layer 3, and the L* value of the white blank region X is 93.0 or more. Also, an ash content included in the decorative sheet 10 is 20.0% by mass or more and 40.0% by mass or less.
As described above, with the conventional decorative sheet for a production of a resin-impregnated decorative plate, it has been difficult to obtain a resin-impregnated decorative plate that can exhibit a gloss matte design while expressing a white design. The inventors of the present application have found that, when visually observing a resin-impregnated decorative plate, a white appearance can be obtained when the L* value in the L*a*b* color system is a predetermined value or more. Also, curable resins (such as melamine based resins, phenolic based resins, diallylphthalate based resins, and polyester resins) impregnated into the decorative sheet are often colored or translucent, which may inhibit the whiteness of the decorative sheet. For this reason, it was found that, in order to ensure a sufficient white designability in the decorative sheet, the white designability (L* value) of the decorative sheet is required to be the predetermined value or more.
In the case of general decorative paper, a solid coating of white ink on the entire surface of the substrate is considered to obtain a white design. However, in the case of decorative sheet used in the production of the resin-impregnated decorative plate, it is common to not apply solid ink on the entire surface to ensure the resin impregnation property of the porous substrate.
In the decorative sheet in the present disclosure, by including a white solid layer on the entire surface of one side of the porous substrate, to the extent that the resin impregnation property of the porous substrate can be obtained, and setting the ash content of the decorative sheet to the predetermined ratio or more, L* value of the white blank region X of the white solid layer 2 not covered with the pattern layer 3 can be the predetermined value or more. Therefore, by using the decorative sheet in the present disclosure, a resin-impregnated decorative plate exhibiting a white design can be obtained.
Furthermore, when the ash content of the decorative sheet in the present disclosure is the predetermined ratio or less, the ink of the releasing layer, that is responsible for the expression of the gloss matte design, can be suppressed from penetrating into the porous substrate, thereby enabling the stable expression of the gloss matte design.

1. Structure of decorative sheet

(1) L* value

In the decorative sheet in the present disclosure, the white solid layer includes a white blank region that is not covered with the pattern layer, and the L* value, in the L*a*b* color system, of the white blank region is 93.0 or more. With such a decorative sheet, as described later, it is possible to produce a resin-impregnated decorative plate capable of expressing a white design. The L* value is more preferably 94.5 or more, and particularly preferably 95.0 or more. With such a decorative sheet, even when the L* value is decreased during the production process of the resin-impregnated decorative plate, it is possible to produce a resin-impregnated decorative plate capable of expressing a white design. Meanwhile, the L* value is, for example, 97.0 or less, and may be 96.0 or less.
The "L*a*b* color system" refers to the color system standardized by the CIE (International Commission on Illumination) which is adopted in JIS Z 8781-4:2013. Incidentally, in the L*a*b*color system, brightness is expressed as L* value, and chromaticity, which indicates hue and saturation, is expressed as a* value and b* value. The L* value substantially represents the whiteness, and the closer to 100, the higher the whiteness, and the closer to 0, the lower the whiteness.
The L* value in the L*a*b* color system of the white blank region is the average value of the values measured at five points on the surface of the white blank region, using CM-3700A from Konica Minolta Inc. Also, the colorimetric region is circular with a diameter of 25.4 mm (area: 506.71 mm²).
As shown in FIG. 1, the white blank region X is the region of the white solid layer 2 that is not covered by the pattern layer 3 and more specifically, the region that is not covered by the pattern layer 3 and the releasing layer 4. Incidentally, when viewed from the thickness direction, a case wherein a part of the releasing layer 4 protrudes from the region where the pattern layer 3 is disposed, is also assumed. In this case, the region covered by colorless and transparent releasing layer 4 and not covered by the pattern layer 3 can referred to as a white blank region.

(2) Ash content

In the present disclosure, the ash content included in the decorative sheet is 20.0% by mass or more, and preferably 22.0% by mass or more. The ratio of the ash content is similar to the content ratio of the decorative sheet, mainly to the inorganic materials, such as white pigments, in the porous substrates. When the ash content is too low, the white design cannot be expressed, even if the white solid layer including white pigment is disposed. Meanwhile, the ash content is 40.0% by mass or less, and preferably 30.0% by mass or less. When the ash content is too high, the gloss mat design cannot be stably expressed.
The ash content in the present disclosure is the value measured by the following measurement method and conditions.

From the decorative sheet, a measurement sample of approximately 5 mg is cut out. Using the following simultaneous thermogravimetry/differential thermal analyzer, the temperature is raised from room temperature to 30°C at a raising rate of 10°C/minute and held at 30°C for 15 minutes, under the following conditions. Then, the temperature is raised to 120°C at a raising rate of 10°C/minute and held at 120°C for 30 minutes. Then, the temperature is raised to 600°C at a raising rate of 10°C/minute and held at 600°C for 30 minutes. Thereby, an ashing of the measurement sample is carried out.

Device: DTG-60A (TG-DTA)
Atmospheric gas: Air
Gas flow rate: 175 [ml/minute]
Initial mass: Approximately 5 mg (the decorative sheet is cut out)
Temperature raising program

Room temperature → raised temperature (10°C /minute) → 30°C, held for 15 minutes → raised temperature (10°C /minute) → 120°C, held for 30 minutes → raised temperature (10°C /minute) → 600°C, held for 30 minutes → completed
As shown in the following calculating formula, the ash content in the present disclosure is a value expressed in a percentage of the mass of the sample after holding at 600°C for 30 minutes, with respect to the mass of the sample after holding at 120°C for 30 minutes, in the temperature raising program. $Ash content (%) = (\begin{array}{l} mass of sample [mg] after holding \\ at 600 ° C for 30 minutes / mass of the sample [mg] after \\ holding at 120 ° C for 30 minutes \end{array}) \times 100$

2. Members of decorative sheet

The decorative sheet in the present disclosure includes at least a porous substrate, a white solid layer, a pattern layer, and a releasing layer.

(1) Releasing layer

At least a part of the releasing layer in the present disclosure is disposed in a pattern on a surface of the pattern layer that is opposite side to the white solid layer. In the production process of a resin-impregnated decorative plate which will be described later, the releasing layer has the ability to release with respect to the cured resin layer disposed between the releasing layer and the release film. By having such ability to release, for example, in the resin-impregnated decorative plate 100 shown in FIG. 3(e) produced using the decorative sheet in the present disclosure, the cured resin layer 32 gives a gloss tone design, and the releasing layer 4 gives a matte tone design, so that a clear gloss-matte tone design can be expressed.
Also, the releasing layer is preferably disposed so that it is aligned with the pattern of the pattern layer. "Aligned with" means that the shape and position of the two patterns of interest roughly conform with each other. Specifically, the shape and position of the pattern of the releasing layer and at least a part of the pattern constituting the pattern of the pattern layer match to the extent that it does not impair the sense of realism and luxury. By disposing the pattern of the releasing layer so as to align with the pattern of the pattern layer, a high texture can be obtained.
The releasing layer includes a resin component. The resin component is typically a cured product (cross-linked structure) of a curable resin. Incidentally, in the present disclosure, the curable resin in the releasing layer may be referred to as curable resin X. Meanwhile, the resin component may be thermoplastic resin. Particularly, the releasing layer preferably includes a cured product of a curable resin. This is because a releasing layer with good wear resistance can be obtained. Also, when the releasing layer includes the cured product of a curable resin, ability to release with respect to the cured resin layer is improved.
Examples of the curable resin X may include ionizing radiation curable resins and thermosetting resins. Examples of the ionizing radiation curable resin may include electron beam curable resins, and ultraviolet ray curable resins.
The ionizing radiation curable resin (ionizing radiation curable compound) are not particularly limited as long as it is a material that generates cross-linking polymerization reaction by irradiation of ionizing radiation and changes to a three-dimensional polymer structure. Examples of the ionizing radiation curable resin may include prepolymers, oligomers and monomers, including polymerizable unsaturated bonds or epoxy groups in the molecule, capable of being cross-linked by irradiation of ionizing radiation. In the present disclosure, one type of the ionizing radiation curable resin may be used alone, and two types or more may be used in a combination. Particularly, as the ionizing radiation curable resin, at least one of a multifunctional monomer and oligomer is preferably used.
Examples of the ionizing radiation curable resin may include (meth)acrylate based resins, such as urethane(meth)acrylate, and ester(meth) acrylate, epoxy(meth)acrylate; silicon based resins such as siloxane; ester based resins; and epoxy based resins. The (meth)acrylate based resin refers to an acrylate based resin or a methacrylate based resin.
The weight average molecular weight of the ionizing radiation curable resin is, for example, 500 or more and 80,000 or less, and may be 1,000 or more and 50,000 or less. The weight average molecular weight is a value measured by gel permeation chromatography (GPC) method, using polystyrene as the reference material.
As the ionizing radiation curable resin, at least a multifunctional monomer or oligomer, with a weight average molecular weight of 500 or more, is preferably included. Examples of such multifunctional monomer or oligomer may include (meth)acrylate based resins such as dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, urethane(meth)acrylate, ester(meth)acrylate, and epoxy(meth)acrylate.
Meanwhile, examples of the thermosetting resins may include unsaturated ester based resins, urethane based resins (including two-liquid curing type polyurethane), epoxy based resins, amino-alkyd based resins, phenolic based resins, urea based resins, diallylphthalate based resins, melamine based resins, guanamine based resins, melamine urea co-condensation based resins, silicon based resins and siloxane based resins.
The releasing layer may include a matting agent. Examples of the matting agent may include inorganic particles and synthetic resin particles. Examples of such inorganic particles may include silica, alumina, calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, and kaolin. Examples of the synthetic resin particles may include acrylic beads, urethane beads, nylon beads, silicone beads, silicone rubber beads, polycarbonate beads, and polyolefin wax (such as polypropylene wax and polyethylene wax).
The average particle size of the matting agent is, for example, 0.3 µm or more and 10 µm or less, may be 0.5 µm or more and 7 µm or less, and may be 1 µm or more and 5 µm or less. The average particle size is D50 in the volume-based particle size distribution measured by a laser diffraction scattering method. The content of the matting agent is, for example, 5 parts by mass or more and 40 parts by mass or less, and may be 10 parts by mass or more and 35 parts by mass or less, with respect to 100 parts by mass of the resin components in the releasing layer.
The releasing layer may include a releasing agent. The ability to release is improved by adding the releasing agent. Examples of the releasing agent may include silicone based releasing agents such as silicone oil; wax based releasing agents such as polyolefin wax; and fluorine based releasing agents. Examples of the silicone oils may include reactive silicone oil and non-reactive silicone oil.
Among the modified silicone oil to which an organic group is introduced to the side chain or at the terminal, the reactive silicone oil refers to one that is reactive due to the properties of the introduced organic group. Specific examples of the reactive silicone oil may include, in, for example, side-chain-type modified silicone oil, both-terminal-type modified silicone oil, one-terminal-type modified silicone oil, and side-chain both-terminal-type modified silicone oil, ones wherein the introduced organic group is amino-modified, epoxy-modified, mercapto-modified, carboxyl-modified, carbinol-modified, phenol-modified, methacryl-modified, and dissimilar functional group-modified. These reactive silicone oils may be used alone, and two or more types may be used as a mixture.
The non-reactive silicone oil is not particularly limited as long as it is a silicone oil not including a reactive functional group such as amino group, epoxy group, mercapto group, carboxy group, hydroxy group, (meth)acryloyl group, and allylic group. Besides the silicone oil including polysiloxane, examples of the non-reactive silicone oil may include polyether modified silicone oil, aralkyl modified silicone oil, fluoroalkyl modified silicone oil, long-chain alkyl modified silicone oil, higher fatty acid ester modified silicone oil, higher fatty acid amide modified silicone oil, and phenyl modified silicone oil. These non-reactive silicone oils may be used alone, and two or more types may be used as a mixture.
The content of the releasing agent is, for example, 0.1 parts by mass or more and 50 parts by mass or less, may be 0.5 part by mass or more and 20 parts by mass or less, may be 3 part by mass or more and 20 parts by mass or less, and may be 3 parts by mass or more and 10 parts by mass or less, with respect to 100 parts by mass of the resin components in the releasing layer.
Also, the releasing layer may be colorless, and may be colored. In the latter case, the releasing layer preferably includes a colorant. As for the colorant, those similar to the colorant used in the pattern layer, which will be described below, may be used.
If necessary, the releasing layer may include an additive such as ultraviolet ray absorbers, infrared ray absorbers, photostabilizers, polymerization inhibitors, crosslinkers, antistatic agents, antioxidants, leveling agents, coupling agents, plasticizers, antifoaming agents, fillers, thermal radial generating agents, and aluminum chelating agents. The thickness of the releasing layer is not particularly limited, and it is, for example, 0.1 µm or more and 20 µm or less.
The releasing layer can be obtained by, for example, applying an ink for forming a releasing layer, including curable resin X, to the surface of the pattern layer that is opposite side to the white solid layer, and curing thereof. Examples of the method for application may include printing methods. Examples of the printing method may include gravure printing, offset printing, screen printing, flexographic printing, electrostatic printing, and inkjet printing.
When the ink for forming a releasing layer includes an electron beam curable resin, a cured product of the electron beam curable resin is usually obtained by irradiating an electron beam. Examples of the electron beam source may include various electron beam accelerators such as Cockcroft-Walton type, Van de Graaff type, resonant transformer type, insulated core transformer type, linear type, dynamitron type, and high frequency type. The energy of the electron beam is, for example, 100 kV or more and 1000 kV or less, and may be 100 kV or more and 300 kV or less. The irradiance level of the electron beam is, for example, 2 Mrad or more and 15 Mrad or less.
When the ink for forming a releasing layer includes an ultraviolet ray curable resin, a cured product of the ultraviolet ray curable resin is usually obtained by irradiating an ultraviolet ray. Examples of the ultraviolet ray source may include an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc lamp, a black light fluorescent lamp, and a metal halide lamp. The wavelength of the ultraviolet ray is, for example, 190 nm or more and 380 nm or less.
When the ink for forming a releasing layer includes a thermosetting resin, a cured product of the thermosetting resin is usually obtained by heating. The heating temperature is appropriately set according to the type of the thermosetting resin. Along with the thermosetting resin, the ink for forming a releasing layer may include curing agents such as cross-linking agents and polymerization initiators; and polymerization accelerators. Examples of the curing agent may include isocyanates, organosulfonates, organoamines, peroxides (such as methyl ethyl ketone peroxide), and radical initiators (azoisobutyronitrile).
The ink for forming a releasing layer may include solvents as necessary. Examples of the solvent may include water; hydrocarbon compounds such as toluene and xylene; alcoholic compounds such as methanol, ethanol, methyl glycol; ketone compounds such as acetone and methyl ethyl ketone; ester compounds such as methyl formate and ethyl acetate; nitrogen containing compounds such as N-methylpyrrolidone, N,N-dimethylformamide; ether compounds such as tetrahydrofuran and dioxane; halogenated hydrocarbon compounds such as methylene chloride and chloroform; and dimethylsulfoxide.

(2) Pattern layer

The pattern layer in the present disclosure is disposed partially (particularly, in a pattern form) on a surface of the white solid layer that is opposite side to the porous substrate. Examples the pattern (design pattern) in the pattern layer may include stone-grain pattern, sand-grain pattern, tile laying pattern, wood-grain pattern, brick laying pattern, fabric-grain pattern, leather tie-dyed pattern, geometric shapes, letters, symbols, abstract patterns, and plant and flower patterns.
The pattern layer includes, for example, a colorant and a resin component (binder resin). Examples of the colorant may include inorganic pigments such as carbon black, titanium white, zinc flower, Bengal red, ultramarine blue and cadmium red; organic pigments such as azo pigment, rake pigment, anthraquinone pigment, quinacridone pigment, phthalocyanine pigment, isoindolinone pigment and dioxidine pigment; metal powder pigments such as aluminum powder and bronze powder; pearlescent pigments such as titanium oxide-coated mica and bismuth oxychloride; fluorescent pigments; and luminous pigments. Dyes may be used as the colorant.
Examples of the resin component may include ester urethane based resins, acrylamide based resins, (meth)acrylic acid based resins, ethylene oxide based resins, N-vinylpyrrolidone based resins, ester based resins, amide based resins, vinyl acetate based resins, vinyl chloride based resins, urethane (meth)acrylic based resins, amino based resins, phenolic based resins, natural polymer (such as polynucleotides, polypeptides and polysaccharides), natural rubbers, and synthetic rubbers. The resin component may be water soluble, and may be lipid soluble.
As the resin component, the pattern layer preferably includes a resin including a polar group. This is because the resin impregnation property into the porous substrate is improved. Examples of the polar group may include hydroxyl group (-OH), amino group (-NH₂), and carboxyl group (-COOH). The polar group may be ionized and stabilized, for example, due to the influence of solvents and other functional groups. Therefore, the "hydroxy group (-OH)" is a concept including "-O^-" in the ionized state, the "amino group (-NH₂)" is a concept including "-NH₃ ⁺" in the ionized state, and the "carboxy group (-COOH)" is a concept including "-COO^-" in the ionized state.
The resin including a polar group is preferably a resin that is dissolved or dispersed in water, methanol or ethanol. This is because the impregnation property of uncured resins such as melamine resin, having hydrophilic properties, is improved. Here, "dissolved or dispersed in water, methanol or ethanol" means satisfying certain criteria in the following test. That is, the following operations are carried out according to Section 3.2 of JIS K8001:2017.

1) As solvent, 100 ml of water, methanol or ethanol are respectively prepared.
2) Under the condition of 20°C ± 5°C, 0.1 g of respective resin (0.1 ml in the case of liquid) are added to the respective solvents.
3) The resultants are shaken strongly for 30 seconds in every 5 minutes to mix thereof.
4) After 30 minutes, the resultants are strongly shaken for 30 seconds, and then, let it stand for 1 minute, and when the following phenomena are not confirmed visibly, it is determined as "dissolved or dispersed".
- There is a precipitation of solids at the bottom of the container.
- Phase separation (oil droplets) of the solvent and resin occurs on the surface of the solvent, in the solvent or on the bottom of the container.

Examples of the resin including a polar group may include aqueous proteins such as casein; cellulose derivatives typified by cellulose, acetylcellulose, nitrocellulose, hydroxypropyl cellulose, and carboxymethylcellulose; polyvinyl alcohol derivatives such as polyvinyl alcohol and polyvinyl butyral resins; amino based resins such as melamine resins; (meth) acrylic acid based resins; phenolic resins; acrylic polyols; and natural polymers (such as polynucleotides, polypeptides, and polysaccharides).
As the resin including a polar group, the pattern layer in the present disclosure preferably includes at least one or more of casein, melamine based resin, polyvinyl alcohol, polyvinyl alcohol derivative, cellulose and cellulose derivative, and more preferably includes casein. As the casein, α-casein, β-casein, γ-casein, or a mixture thereof may be used. Also, as the casein, the derivatives typified by casein sodium and casein ammonium can be used alone or in a combination.
The pattern layer may include additives, such as fillers (such as silica), extender pigments (such as organic beads), neutralizers, and surfactants, if necessary. The thickness of the pattern layer is not particularly limited, and it is, for example, 0.1 µm or more and 20 µm or less.
Examples of the method for forming a pattern layer may include applying methods using an ink for forming a pattern layer including a colorant, a binder resin, and a solvent (or a dispersant). For example, a pattern layer is obtained by coating the surface of the white solid layer that is opposite side to the porous substrate with the ink for forming a pattern layer, and drying.
Examples of the solvent (or dispersant) may include petroleum based organic solvents such as hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane, and methylcyclohexane; ester based organic solvent such as ethyl acetate, butyl acetate, 2-methoxyethyl acetate, and 2-ethoxyethyl acetate; alcoholic based organic solvents such as methyl alcohol, ethyl alcohol, normal propyl alcohol, isopropyl alcohol, isobutyl alcohol, ethylene glycol, and propylene glycol; ketone base organic solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether based organic solvents such as diethyl ether, dioxane, and tetrahydrofuran; chloride based organic solvents such as dichloromethane, carbon tetrachloride, trichloro ethylene, and tetrachloro ethylene; and inorganic solvents such as water.
Examples of the method for application may include printing methods. Examples of the printing method may include gravure printing, offset printing, screen printing, flexographic printing, electrostatic printing, and inkjet printing.

(3) White solid layer

The white solid layer in the present disclosure is disposed so as to cover the entire surface of one surface of the porous substrate. The entire surface of one surface of a porous substrate refers to, based on the portion that functions as the decorative sheet among one surface of the porous substrate, the region of 90% or more thereof. Based on the portion that functions as the decorative sheet among one surface of the porous substrate, the white solid layer may be disposed so as to cover 95% or more thereof, and may be disposed so as to cover 100% thereof.
The condition where "the white solid layer is disposed so as to cover the entire surface of one surface of the porous substrate" is explained more specifically, referring to some examples. As shown in FIG. 6(a), viewing from the thickness direction, when the porous substrate 1 is completely covered by the white solid layer 2, the white solid layer 2 is disposed so as to cover the entire surface of the porous substrate 1 (100% of the portion that functions as the decorative sheet). Also, as shown in FIG. 6(b), viewing from the thickness direction, when both ends of the porous substrate 1 are exposed from the white solid layer 2, the both ends do not function as the decorative sheet. Therefore, the entire surface of the porous substrate 1 is defined, excluding the region that does not function as the decorative sheet. In FIG. 6(b), the white solid layer 2 is disposed so as to cover the entire surface of the porous substrate 1 (100% of the portion that functions as the decorative sheet). Similarly, as shown in FIG. 6(c), viewing from the thickness direction, when the outer periphery of the porous substrate 1 is located on the outer side than the outer periphery of the white solid layer 2 for the whole circumference, the region of the porous substrate 1, exposed from the white solid layer 2, does not function as the decorative sheet. Therefore, the entire surface of the porous substrate 1 is defined, excluding the region that does not function as the decorative sheet. In FIG. 6(c), the white solid layer 2 is disposed so as to cover the entire surface of the porous substrate 1 (100% of the portion that functions as the decorative sheet).
Meanwhile, in FIG. 6(d), viewing from the thickness direction, the entirety of the surface of the porous substrate 1 functions as the decorative sheet. Meanwhile, on the inner side of the outer periphery of the white solid layer 2, there is a region α wherein the white solid layer 2 is not formed (for example, an uncoated portion produced for the purpose of design expression). In this case, when the total area of the region α is less than 10% with respect to the surface of the porous substrate 1 (the portion that functions as the decorative sheet), it can be said that "the white solid layer is disposed so as to cover the entire surface of one surface of the porous substrate". Also, in FIG. 6(e), viewing from the thickness direction, the entirety of the surface of the porous substrate 1 functions as the decorative sheet. Meanwhile, there is a region α wherein the white solid layer 2 is not formed (for example, an uncoated portion produced for the purpose of design expression), so as to divide the white solid layer 2. In this case, when the total area of the region α is less than 10% with respect to the surface of the porous substrate 1 (the portion that functions as the decorative sheet), it can be said that "the white solid layer is disposed so as to cover the entire surface of one surface of the porous substrate". Similarly, in FIG. 6(f), viewing from the thickness direction, the entirety of the surface of the porous substrate 1 functions as the decorative sheet. Meanwhile, there is a region α wherein the white solid layer 2 is not formed. In this case, when the total area of the region α is less than 10% with respect to the surface of the porous substrate 1 (the portion that functions as the decorative sheet), it can be said that "the white solid layer is disposed so as to cover the entire surface of one surface of the porous substrate".
Also, as shown in FIG. 6(g), viewing from the thickness direction, when both ends of the porous substrate 1 are exposed from the white solid layer 2, the both ends do not function as the decorative sheet. Therefore, the entire surface of the porous substrate 1 is defined, excluding the region that does not function as the decorative sheet. In FIG. 6(g), on the inner side of the outer periphery of the white solid layer 2, there is a region α wherein the white solid layer 2 is not formed (for example, an uncoated portion produced for the purpose of design expression). In this case, when the total area of the region α is less than 10% with respect to the portion that functions as the decorative sheet, among the surface of the porous substrate 1, it can be said that "the white solid layer is disposed so as to cover the entire surface of one surface of the porous substrate". Also, as shown in FIG. 6(h), viewing from the thickness direction, when the outer periphery of the porous substrate 1 is located on the outer side than the outer periphery O₁ of the white solid layer 2 for the whole circumference, the region of the porous substrate 1, exposed from the white solid layer 2 on the outer side than the outer periphery O₁, does not function as the decorative sheet. Therefore, the entire surface of the porous substrate 1 is defined, excluding the region that does not function as the decorative sheet. As shown in FIG. 6(h), when the outer periphery O₂ of the white solid layer 2 has a complex shape, the outer periphery O₁ of the square is set so that the area of the white solid layer 2 is maximized. Also, in FIG. 6(h), there is a region α wherein the white solid layer 2 is not formed. In this case, when the total area of the region α is less than 10% with respect to the portion that functions as the decorative sheet, among the surface of the porous substrate 1, it can be said that "the white solid layer is disposed so as to cover the entire surface of one surface of the porous substrate".
The white solid layer includes a white pigment. The white pigment is not particularly limited, and examples thereof may include titanium oxide, calcium carbonate, zinc oxide, barium sulfate, and silica. Among them, titanium oxide and calcium carbonate are preferable. In the present disclosure, titanium oxide is particularly preferable due to its good whiteness and hiding property. The ratio of the white pigment in the white solid layer is, for example, 50% by mass or more, and preferably 60% by mass or more. Meanwhile, ratio of the white pigment is, for example, 95% by mass or less, and preferably 90% by mass or less.
In addition to the white pigment, the white solid layer includes, for example, resin components, additives and solvents (or dispersion media). Examples of the resin component, additive, and solvent (or dispersion medium) may include those similar to the resin component, additive, and solvent (or dispersion medium) exemplified for the pattern layer described above.
Also, as the resin component, the white solid layer preferably includes a resin including a polar group. This is because the resin impregnation property into the porous substrate is good. Examples of the resin including a polar group may include those similar to the resin including a polar group exemplified for the pattern layer described above.
As the resin including a polar group, the white solid layer in the present disclosure preferably includes at least one or more of casein, melamine based resin, polyvinyl alcohol, polyvinyl alcohol derivative, cellulose and cellulose derivative, and more preferably includes casein. As the casein, α-casein, β-casein, γ-casein, or a mixture thereof may be used. Also, as the casein, the derivatives typified by casein sodium and casein ammonium can be used alone or in a combination.
Also, viewing the decorative sheet from the thickness direction, the ratio (S₂/S₁) of the area S₂ of the white blank region (the region that is not covered with the pattern layer) in the white solid layer, with respect to the total area S₁ of the white solid layer is, for example, 5% or more, and may be 10% or more. When the ratio (S₂/S₁) is in the above range, the design effect due to the white blank region can be sufficiently obtained. Meanwhile, the ratio (S₂/S₁) is, for example, 95% or less, may be 80% or less, and may be 70% or less.
The contact angle with respect to pure water, of the region exposed from the releasing layer, as view from the thickness direction, is preferably low. Viewing from the thickness direction, the region exposed from the releasing layer is the region where the white solid layer is formed and the releasing layer is not formed. The surface of the region exposed from the releasing layer may be the surface of the white solid layer, and may be the surface of the pattern layer. This is because the impregnation property of uncured resins such as melamine resin, having hydrophilic properties, is better. The contact angle with respect to pure water is determined by the following method. In other words, the decorative sheet is placed on a horizontal surface so that the releasing layer side is the top surface. Then, a water droplet (pure water, 2.0 µL) is dripped on to the horizontal surface, on the white solid layer, from the perpendicular direction. At this time, the water droplet is not dripped on the boundary between the white solid layer and the releasing layer, for example, but is dripped so that all the water droplets come into contact with the region exposed from the releasing layer. After dripping the droplet, wait for one second and the contact angle between the white solid layer and the pure water is measured with a contact angle meter (fully automatic contact angel meter DMo-702 from Kyowa Interface Science Co., Ltd). The above measurement is carried out at arbitrary 10 locations, and the average value thereof is regarded as the contact angle with respect to pure water. The contact angle with respect to pure water may be 80.0° or less, may be 70.0° or less, and may be 60.0° or less. Meanwhile, the contact angle with respect to water may be 0°. That is, pure water may completely penetrate into the decorative sheet.
In the present disclosure, the wettability of the region exposed from the releasing layer described above is preferably high. This is because the impregnation property of uncured resins such as melamine resin, having hydrophilic properties, is better. The wettability is determined by the following method.

1) Prepare tension checkers (from Pacific Chemical Co. Ltd.) with dyne numbers of 40 mN/m, 46 mN/m, 50 mN/m, 54 mN/m, 60 mN/m, 67 mN/m, and 70 mN/m, respectively.
2) Draw a line, of 30 cm or more, on the surface of the decorative sheet with the tension checker. At this time, do not draw the line only on the releasing layer, but draw the line so that the drawn line portion drawn includes the region exposed from the releasing layer described above.
3) After drawing the line, stand the decorative sheet still for 2 seconds, and wipe the surface with a dry cloth. Then, visually check the white blank region for an ink mark or discoloration due to the tension checker. Carry out this operation for three times for per dye number.
4) Carry out the operations of the above 2) and 3) respectively for each prepared dye number.
5) Among the dye numbers wherein an ink mark or discoloration was observed as the result of 4) above (including a case wherein an ink mark or discoloration was observed, even for only one time out of the three), the one with the highest value is regarded as the wettability of the decorative sheet.

The wettability is, for example, 50 mN/m or more, may be 54 mN/m or more, and may be 60 mN/m or more. Meanwhile, the wettability is, for example, 70 mN/m or less.
The ratio of the resin including a polar group described above, with respect to the resin components included in the white solid layer is, for example, 20% by mass or more, may be 30% by mass or more, may be 40% by mass or more, and may be 50% by mass or more. Meanwhile, the ratio of the resin including a polar group is, for example, 100% by mass or less, and may be 90% by mass or more. When the content of the resin including a polar group is in the above range, the permeation of the ink of the releasing layer into the porous substrate may further be suppressed, without inhibiting the permeation of the uncured resin with respect to the porous substrate.
Also, as the resin component, the white solid layer may include other resins, in addition to the resin including a polar group described above. Examples of the other resins may include (meth)acrylic based resins, ester urethane based resins, acrylamide based resins, ethylene oxide based resins, N-vinylpyrrolidone based resins, ester based resins, amide based resins, vinyl acetate based resins, vinyl chloride based resins, urethane (meth)acrylic based resins, natural rubbers, and synthetic rubbers. Among them, (meth)acrylic based resins, and urethane(meth)acrylic based resins are preferable.
The thickness of the white solid layer is not particularly limited, and is, for example, 1 µm or more, preferably 2 µm or more, and may be 3 µm or more. When the thickness of the white solid layer is in the above range, it has excellent whiteness. Meanwhile, the thickness is preferably 8 µm or less, and may be 6 µm or less. When the thickness of the white solid layer is in the above range, good resin impregnation property into the porous substrate is obtained. The thickness of the white solid layer is the average value of the thickness measured at 10 locations by observing the cross-section, obtained by cutting the decorative sheet in the thickness direction, with an optical microscope.
The applying amount (basis weight) of the white solid layer is not particularly limited, and is, for example, 1.0 g/m² or more, preferably 2.0 g/m² or more, and may be 3.0 g/m² or more. When the applying amount of the white solid layer is the above value or more, a white solid layer having excellent whiteness is obtained. Meanwhile, applying amount (basis weight) of the white solid layer is preferably, for example, 10 g/m² or less, and may be 8 g/m² or less. When the applying amount of the white solid layer is the above value or less, good resin impregnation property into the porous substrate is obtained.
In the present disclosure, the gloss value of the white blank region (region not covered with the pattern layer) of the white solid layer, at 75°, is, for example, 6.0 or more, preferably 8.0 or more, and more preferably 10.0 or more. When the gloss value at 75° of the white blank region of the white solid layer is in the above range, it is easy to obtain a resin-impregnated decorative plate that can express a white design. Meanwhile, the gloss value at 75°is, for example, 25.0 or less, and preferably 20.0 or less. When the gloss value at 75° of the white blank region of the white solid layer is in the above range, the inhibition of melamine impregnation due to the white solid layer can be prevented, and the processability can be maintained well.
In the present disclosure, the gloss value of the white blank region of the white solid layer, at 75°, is the specular glossiness at 75° measured according to Method 2 of JIS Z 8741:1997, and is the value measured by the following method.
Placed a decorative sheet so that the releasing layer side is on the upper side, and from the releasing layer side, and using a gloss meter, measure the specular glossiness at 75° according to Method 2 of JIS Z 8741:1997.
The gloss value of the white blank region of the white solid layer at 75° is the average value of the values measured at arbitrary ten points of the white blank region (region not covered with the pattern layer). At each measurement point, the measurement is carried out after confirming that the white blank region of the white solid layer is at the center of the measurement region of the gloss meter, and that the ratio of the area of this white blank region is 50% or more of the area of the measurement region.
The gloss value of the white blank region of the white solid layer at 75° can be increased by, for example, increasing the thickness of the white solid layer, and decreased by reducing the thickness of the white solid layer.
Examples of the method for forming the white solid layer may include applying methods using an ink for a white solid layer including a white pigment, a resin component, an additive and a solvent (or a dispersant). For example, a white solid layer is obtained by coating one surface of a porous substrate with the ink for forming a white solid layer, and drying.
Examples of the solvent (or dispersant) may include petroleum based organic solvents such as hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane, and methylcyclohexane; ester based organic solvent such as ethyl acetate, butyl acetate, 2-methoxyethyl acetate, and 2-ethoxyethyl acetate; alcoholic based organic solvents such as methyl alcohol, ethyl alcohol, normal propyl alcohol, isopropyl alcohol, isobutyl alcohol, ethylene glycol, and propylene glycol; ketone base organic solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether based organic solvents such as diethyl ether, dioxane, and tetrahydrofuran; chloride based organic solvents such as dichloromethane, carbon tetrachloride, trichloro ethylene, and tetrachloro ethylene; and inorganic solvents such as water.
Also, examples of the coating method for forming the white solid layer may include various coating methods such as roll coating, knife coating, air knife coating, die coating, lip coating, comma coating, kiss coating, flow coating, and dip coating.
Examples of the printing method may include a gravure printing method.
The white solid layer may be disposed so as to cover the entire surface of one surface of the porous substrate by coating for once, and may be disposed so as to cover the entire surface of one surface of the porous substrate by a plurality time of coating. In the latter case, the layer formed by coating for once may have a patterned shape.

(4) Porous substrate

The porous substrate in the present disclosure is a substrate into which uncured resin (curable resin Y) such as thermosetting resin is impregnated, during the production of the resin-impregnated decorative plate. Examples of the porous substrate may include permeable fibrous substrates. Examples of the permeable fibrous substrate may include paper, synthesized paper, non-woven fabric and woven fabric. Examples of the paper may include titanium paper, tissue paper, kraft paper, linter paper, paperboard, gypsum board paper, high-quality paper, coated paper, parchment paper, and Japanese paper. Also, vinyl wallpaper webs (paper dry laminated with polyvinyl chloride resin) can be used as the fibrous substrate. Also, other examples of the fibrous substrate may include non-woven or woven fabrics including synthetic resin fibers such as polyester, vinylon, polyethylene and polypropylene. Among these porous substrates, titanium paper, tissue paper, kraft paper, coated paper, art paper, vegetable parchment paper, glassine paper, parchment paper, paraffin paper, and Japanese paper are preferable in view of the impregnation property of the thermosetting resin. In the present disclosure, titanium paper is preferable from the viewpoint of obtaining the L* value. Further, titanium paper has excellent impregnation property of curable resin Y.
The porous substrate may be colored. For example, at the stage of production of the porous substrate, a porous substrate colored in white is obtained by blending white pigments. For example, when the porous substrate is paper, paper colored in white is obtained by mixing white pigments such as titanium dioxide at the papermaking stage. Also, the content of the white pigment is not particularly limited as long as the content is such that the ash content is the ratio described above. Particularly, the white pigment used for the porous substrate constituting the decorative sheet in the present disclosure is required to have a function to adjust the whiteness of the porous substrate; and a function to adjust the permeability of the porous substrate. In the present disclosure, the type and content of the white pigment are set so that the L* value described above is obtained and the ash content is in the above range, that is, to adjust the permeability of the porous substrate. Also, the porous substrate may include various additives such as fillers, frosting agents, foaming agents, flame retardants, lubricants, antistatic agents, antioxidants, ultraviolet ray absorber and photostabilizers, if necessary.
The basis weight of the porous substrate is not particularly limited, and is, for example, 40 g/m² or more and 150 g/m² or less. The thickness of the porous substrate is not particularly limited, and it is, for example, 50 µm or more and 70 µm or less. For example, in order to improve the close adhesiveness of the ink for forming the white solid layer, the white solid layer side surface of the porous substrate may be subjected to a corona discharge treatment.

3. Decorative sheet

In the decorative sheet in the present disclosure, the b* value of the white blank region, in the L*a*b* color system, is preferably 4.5 or less, and more preferably 4.0 or less. With such a decorative sheet, a resin-impregnated decorative plate wherein yellowness is suppressed and having high whiteness can be obtained. Meanwhile, the b* value is, for example, 3.0 or more.
The decorative sheet in the present disclosure is used for a production of a resin-impregnated decorative plate. Since the resin-impregnated decorative plate will be described later, description herein is omitted.
When an impregnation property test using melamine resin is carried out to the decorative sheet in the present disclosure, the impregnation amount of the melamine resin, into the decorative sheet, is for example, 35 g/m² or more, and may be 45 g/m² or more. Meanwhile, the impregnation amount of the melamine resin, into the decorative sheet, is for example, 80 g/m² or less, and may be 60 g/m² or less. The details of the impregnation property test will be described in the following Examples.

B. Resin-impregnated decorative plate

The resin-impregnated decorative plate in the present disclosure will be hereinafter described in detail. FIG. 2 is a schematic cross-sectional view exemplifying the resin-impregnated decorative plate in the present disclosure.
The resin-impregnated decorative plate 100 shown in FIG. 2 includes the decorative sheet 10 described above, a core substrate 20 disposed so as to face the porous substrate 1 of the decorative sheet; and a cured resin layer 32 disposed on the white blank region X, and including a cured product of curable resin Y, wherein the core substrate 20 and the porous substrate 1 include the cured product of the curable resin Y. In the resin-impregnated decorative plate 100 in the present disclosure, the L* value of the white blank region X is 88.0 or more, when measured via the cured resin layer 32.
Since the decorative sheet described above is provided in the resin-impregnated decorative plate in the present disclosure, it is possible to stably exhibit a gloss matte design, while expressing a white design.

1. Decorative sheet

The details of the decorative sheet are as described above.

2. Core substrate

The resin-impregnated decorative plate in the present disclosure includes a porous core substrate 20 on the porous substrate 1 side surface of the decorative sheet 10 (the surface of the decorative sheet 10 located on the porous substrate 1 side, based on the white solid layer 2). Examples of the core substrate 20 may include phenol resin-impregnated paper. The phenol resin-impregnated paper is a paper obtained by, for example, impregnating phenol resin into a kraft paper, that is a core paper, and drying it.

3. Cured product of curable resin and cured resin layer

The core substrate and the porous substrate in the present disclosure include a cured product of a curable resin Y. The resin-impregnated decorative plate includes a cured resin layer disposed on the white blank region. The cured product of curable resin filled into the core substrate and porous substrate; and the cured product of curable resin included in the cured resin layer are formed with the same curable resin Y, as described later. These cured resins are, for example, a cured product of thermosetting resins described below.
The thickness of the cured resin layer is not particularly limited, and is, for example, 1 µm or more, and may be 10 µm or more. Meanwhile, the thickness is, for example, 500 µm or less, and may be 300 µm or less.

4. L* value

In the resin-impregnated decorative plate in the present disclosure, the L* value of the white blank region X, when measured via the cured resin layer 32, is 88.0 or more, and may be 90.0 or more. Meanwhile, the L* value is not particularly limited, and may be, for example, 92.0 or less, and may be 91.0 or less.

5. Method for producing

FIGS. 3 are schematic cross-sectional views exemplifying a method for producing a resin-impregnated decorative plate using the decorative sheet in the present disclosure.
Firstly, as shown in FIG. 3(a) and FIG. 3(b), the porous substrate 1 of the decorative sheet 10 described above 10 is impregnated with thermosetting resin via the white solid layer 2 so that the thermosetting resin is included in the porous substrate 1, and a thermosetting resin layer 30' which covers the white solid layer 2, pattern layer 3 and releasing layer 4, is formed. As the thermosetting resin, thermosetting type resins may be widely used. Examples of the thermosetting resin may include melamine based resins (melamine based resin precursors), melamine-urea co-condensate based resins, unsaturated polyester based resins, polyurethane based resin (including two-liquid curing type polyurethane), epoxy based resins, aminoalkyd based resins, phenolic based resins, urea based resins, diallylphthalate based resins, guanamine based resins, silicon based resins and polysiloxane based resins. Examples of the method for impregnating the thermosetting resin may include a method wherein a decorative sheet 10 is immersed into a bath including thermosetting resin; a method wherein a decorative sheet 10 is coated with thermosetting resin by a coater such as a kiss coater or a comma coater; and a method wherein thermosetting resin is sprayed onto a decorative sheet 10 by a spray device or a shower device.
Also, as shown in FIG. 3(c), a first stacked body 51' is produced by disposing a release film 40 on the thermosetting resin layer 30' that is opposite side to the white solid layer 2, and disposing a core substrate 20 on the porous substrate 1 side surface of the decorative sheet 10 (the surface of the decorative sheet 10 located on the porous substrate 1 side, based on the white solid layer 2). Also, the release film may include a peeling layer including a cured product of an ionizing radiation curable resin composition, on the surface facing the thermosetting resin layer.
Then, as shown in FIG. 3(d), a second stacked body 52' is produced by heating and pressurizing the first stacked body 51' to cure the thermosetting resin, and forming a cured resin layer 31' from the thermosetting resin layer 30'. The heating temperature is, for example, 90°C or more, and 160°C or less. Also, the heating time is, for example, 30 seconds or more and 30 minutes or less. Also, by pressurizing, the smoothness of the release film 40 is reflected onto the surface of the cured resin layer 31'.
Then, as shown in FIG. 3(e), release film 40 is peeled off from the second stacked body 52', and at the same time, the cured resin layer 31', located between releasing layer 4 and release film 40, is peeled off to the release film 40 side. At this time, the cured resin layer 31' which has not been peeled off to the release film 40 side becomes a gloss layer 32. Thereby obtaining a resin-impregnated decorative plate 100 comprising: a porous substrate 1; a white solid layer 2 disposed on an entire surface of one surface of the porous substrate 1; a pattern layer 3 disposed partially on a surface of the white solid layer 2 that is opposite side to the porous substrate 1; a releasing layer (matte layer) 4 disposed in a pattern on a surface of the pattern layer 3 that is opposite side to the white solid layer 2; and a cured resin layer (gloss layer) 32 disposed on the white blank region of the decorative sheet.
The resin-impregnated decorative plate in the present disclosure is, for example, used by disposing thereof on the surface of a base member. Examples of the base member may include woody members, resin members, metal members, and ceramic members. Examples of the woody member may include wood single panel, plywood panel, particle board, and woody fiberboard. Examples of the wood used for the woody member may include cedar, hinoki cypress, pine, and lauan. Examples of the resin used for the resin member may include vinyl chloride based resins, (meth)acrylic based resins, ester based resins, styrene based resins, olefin based resins, acrylonitrile-butadiene-styrene based copolymers (ABS based resins), phenolic based resins, cellulose based resins, carbonate based resins, melamine based resins, and rubber. Examples of the metal used for the metal member may include iron, and aluminum. The material of the ceramic member may be ceramics such as glass and pottery, may be non-cement ceramic based material such as gypsum, and may be non-pottery ceramic based material such as ALC (lightweight aerated concrete).
Examples of the use application of the resin-impregnated decorative plate in the present disclosure may include construction materials and furniture. The construction material may be interior material, and may be exterior material. Examples of the construction material may include walls, floors, ceilings, doors, and shelves. Examples of furniture may include tables, desks and cabinets.
The present disclosure is not limited to the embodiments. The embodiments are exemplification, and any other variations are intended to be included in the technical scope of the present disclosure if they have substantially the same constitution as the technical idea described in the claim of the present disclosure and offer similar operation and effect thereto.

Examples

[Example 1]

(Production of decorative sheet)

Preparing titanium paper with basis weight of 80 g/m² (PM-77P from KJ Specialty Paper Co., Ltd.) as the porous substrate, and a white solid layer with a thickness of 2 µm was formed on the entire surface of one surface of the porous substrate, by gravure printing method, using a printing ink for forming a white solid layer having the following composition. Further, using the printing ink for forming a pattern layer having the following composition, a pattern layer having a stone-grid pattern was formed on the surface of the white solid layer that is opposite to the porous substrate.

White pigment (titanium oxide) 40 parts by mass
Casein/acrylic based resin (mass ratio 45:55) 10 parts by mass
Water 40 parts by mass
Dipropyl glycol 5 parts by mass
Isopropyl alcohol 5 parts by mass

Pigments (such as azo based, quinacridone based, carbon black) 10 parts by mass
Casein/acrylic (mass ratio 45:55) 10 parts by mass
Water 70 parts by mass
Dipropyl glycol 5 parts by mass
Isopropyl alcohol 5 parts by mass

Using a process homogenizer PH91 (from SMT Co., Ltd.), 60 parts by mass of an ionizing radiation curable monomer (Aronix M400 from Toagosei Ltd.), 0.6 parts by mass of reactive silicone (X-22-164B from Shin-Etsu Chemical Co., Ltd.) and 40 parts by mass of methyl ethyl ketone (from Maruzen Petrochemical Co., Ltd.) were stirred for 1 hour at number of revolutions of 2000 rpm to prepare an ink for forming a releasing layer.
Further, a releasing layer having a thickness of 2 µm was formed in a pattern by coating the pattern layer with the ink for forming a releasing layer so as to align with the stone-grain pattern of the pattern layer, and irradiating electron beams of 3 Mrad at an accelerating voltage of 165 kV. Thereby, a decorative sheet including a porous substrate, a white solid layer, a pattern layer, and a releasing layer in a patter, in this order, was produced. Incidentally, the ratio (S₂/S₁) of the area S₂ of the white blank region (the region that is not covered with the pattern layer) with respect to the total area S₁ of the white solid layer, as view from the thickness direction, was adjusted to be 50% or more and 60% or less, for all the Examples and Comparative Examples described below.

(Production of release film)

The easy adhesive surface of a polyethylene terephthalate film (Cosmo Shine (registered trademark) A4160 from Toyobo Co., Ltd.) having a thickness of 50 µm was coated with a coating solution including 100 parts by mass of an ionizing radiation curable monomer, 2 parts by mass of a reactive silicone, 8 parts by mass of silica and 50 parts by mass of ethyl acetate at an amount of 5 g/m² (dried), and electron beams were irradiated at 5 Mrad and an accelerating voltage of 165 kV to cure. Thereby a release film including a cured resin layer was produced.

(Preparation of melamine decorative plate)

Using an impregnation device for impregnation, the produced decorative sheet was impregnated with a liquid uncured melamine resin composition including 60 parts by mass of uncured melamine resin (water-soluble methylol melamine resin, Nikaresin S-260 from Nippon Carbide Industries Co., Inc.), 35 parts by mass of water and 5 parts by mass of isopropyl alcohol so that the ratio of the uncured melamine resin composition was 80 g/m² (dried), and dried to produce an impregnated decorative sheet.
The impregnated decorative sheet was stacked on 3 sheets of phenolic resin-impregnated core paper with a basis weight of 245 g/m² (obtained by impregnating core kraft paper with a liquid uncured resin composition made from phenolic resin) produced by impregnating kraft paper with the phenolic resin liquid. Further, the release film was stacked on the releasing layer side surface of the impregnated decorative sheet so that the cured resin layer of the release film was in contact with the printed surface of the impregnated decorative sheet, and a first stacked body was obtained. The formed stacked body was sandwiched between two mirror plates, and heat molded using a hot press device, at a pressure of 100 kg/cm², under the conditions of molding temperature of 150°C for 10 minutes to produce a molded body (second stacked body). In the molded body, a melamine resin layer including cured melamine resin was formed between the releasing layer and the release film.
Among the cured resin layer, the portion that covers the releasing layer was removed by peeling the release film off from the cured resin layer including the cured product of the melamine resin. At the portion where the releasing layer is not provided, the cured resin layer that has not been removed remained as a gloss layer. Thus, a melamine decorative plate was obtained.

[Example 2]

A decorative sheet was produced and a melamine decorative plate was obtained in the same manner as in Example 1 except that the thickness of the white solid layer was set to 6 µm.

[Example 3]

A decorative sheet was produced and a melamine decorative plate was obtained in the same manner as in Example 1 except that the thickness of the white solid layer was set to 1 µm.

[Example 4]

A decorative sheet was produced and a melamine decorative plate was obtained in the same manner as in Example 1 except that the porous substrate was changed to KW801P from KJ Specialty Paper Co., Ltd.

[Example 5]

A decorative sheet was produced and a melamine decorative plate was obtained in the same manner as in Example 1 except that the porous substrate was changed to PM-79P from KJ Specialty Paper Co., Ltd.

[Comparative Example 1]

A decorative sheet was produced and a melamine decorative plate was obtained in the same manner as in Example 1 except that the white solid layer was not formed.

[Comparative Example 2]

A decorative sheet was produced and a melamine decorative plate was obtained in the same manner as in Example 1 except that the printing ink for the white solid layer was changed to a transparent ink (including no titanium oxide).

[Comparative Example 3]

A decorative sheet was produced and a melamine decorative plate was obtained in the same manner as in Example 1 except that the porous substrate was changed to PM-28P from KJ Specialty Paper Co., Ltd.

[Comparative Example 4]

A decorative sheet was produced and a melamine decorative plate was obtained in the same manner as in Example 1 except that the porous substrate was changed to KSH801P from KJ Specialty Paper Co., Ltd.

Ash content measurement

The ash content of the decorative sheet produced above was measured by the method described above. The results are shown in Table 1.

[Evaluation]

(L* value and b* values decorative sheet and melamine decorative plate)

The L* value and b* value, of the white blank region of the decorative sheet produced above, in the L*a*b* color system, and the L* value and b* value, of the white blank region measured via the cured resin layer of the melamine decorative plate, in the L*a*b* color system, were measured by the method described above. The results are shown in Table 1.

(Gloss value of decorative sheet at 75°)

The gloss value, of the white blank region of the decorative sheet produced above, at 75°, was measured by the method described above. The results are shown in Table 1.

(Contact angle with respect to pure water)

For the decorative sheet produced above, the contact angle with respect to pure water of the region exposed from the releasing layer was measured by the method described above. The results are shown in Table 1.

[Measurement of wettability]

For the decorative sheet produced above, the wettability of the region exposed from the releasing layer was measured by the method described above. The results are shown in Table 1.

(Evaluation of white designability)

The white designability of the obtained melamine decorative plate was evaluated by visual observation. In the evaluation, a reference melamine decorative plate 1 and a reference melamine decorative plate 2 prepared separately were used as the whiteness criteria.
The reference melamine decorative plate 1 was prepared by impregnating a titanium paper (PM-77P from KJ Specialty Paper Co., Ltd.) with an uncured melamine resin composition in the same manner as (Preparation of melamine decorative plate) in Example 1, and heat pressing. The reference melamine decorative plate 2 was prepared by impregnating a titanium paper (KW801P from KJ Specialty Paper Co., Ltd.) with an uncured melamine resin composition in the same manner as (Preparation of melamine decorative plate) in Example 1, and heat pressing.
The observer visually compared the reference melamine decorative plate 1 and the reference melamine decorative plate 2 with the decorative plate produced in Examples and Comparative Examples. Each reference decorative plate used was scored in a five-point scale (3 points for one equivalent to the reference, 1 point for the lowest white designability, and 5 points for the highest white designability) from 1 point to 5 points. The evaluation was respectively carried out by 10 observers, the average points of every observer was calculated, and the white designability was evaluated based on the following criteria.

• Evaluation criteria

A: The average score was respectively 3 or more for both of the reference melamine decorative plates 1 and 2.
B: Although the average score was less than 3 for the reference melamine decorative plate 2, the average score was 3 or more for the reference melamine decorative plate 1.
C: The average score was respectively less than 3 for both of the reference melamine decorative plates 1 and 2, and reddish tone or yellowish tone was observed.

(Evaluation of gloss matte designability)

The gloss matte designability of the obtained melamine decorative plate was evaluated visually. Specifically, under the light source of a natural color fluorescent lamp color rendering AA (model number: FLR40S•D-SDL/M from Panasonic Corporation), the obtained decorative plate was respectively observed visually from the position 50 cm away from the decorative plate, and the gloss matte designability and the condition of the matte portion (releasing layer) were checked.
Observers scored the gloss matte designability in a five-point scale (1 point for the worst, and 5 points for the best) from 1 point to 5 points. Incidentally, the evaluation graded as follows: 1 point when a large part of the melamine was not peeled off, or marked whitening was observed in the matte portion and in the vicinity thereof, and a sufficient gloss matte design was not confirmed; and 5 points when the peeled melamine residue was not confirmed in the matte portion, and a sufficient gloss matte design was confirmed. The evaluation was respectively carried out by 10 observers, the average points of every observer was calculated, and the gloss matte designability was evaluated based on the following criteria.

• Evaluation criteria

A: The average score was 3 or more, when evaluating the gloss matte designability
B: The average score was 2 or more and less than 3, when evaluating the gloss matte designability
C: The average score was less than 2, when evaluating the gloss matte designability

(Impregnation property evaluation)

The impregnation property of the produced decorative sheet was measured by the following method.

1) A circular sample with a radius of 2 cm was cut out from a decorative sheet, and the mass of the sample was measured (mass of the sample before the test).
2) FIG. 4(a) is a schematic cross-sectional view of the container used for the impregnation property evaluation, and FIGS. 4(b) and (c) are a schematic cross-sectional view and a schematic perspective view of the container lid. As shown in FIGS. 4, a polyethylene container (content capacity of approximately 300 ml) 51 (FIG. 4(a)) including a first opening portion O1, and a lid 52 (FIG. 4(b) and FIG. 4(c)), which can be fixed to the container 51 and includes a second opening portion O₂ were prepared. Incidentally, the shape of the first opening portion was circular with a diameter of 3 cm (impregnation area of approximately 0.0007 m²). As shown in FIG. 5(a), 100 g of uncured melamine resin U (60 g of water-soluble methylol melamine resin (Nikaresin S-260 from Nippon Carbide Industries Co., Inc.) dissolved in 40 g of pure water) was added into the container 51. The sample S was then disposed so as to cover the first opening portion O1. Then, the sample S was set by using the lid 52, and fixing the container 1 and the lid 52. At this time, the sample S was set so that the white solid layer surface faces the inside of the container.
3) As shown in FIG. 5(b), the container 51 was turned over, and the sample S was impregnated with the uncured melamine resin U.
4) After 30 seconds, as shown in FIG. 5(c), the container 51 was turned over again, and the sample S was taken out immediately.
5) As shown in FIG. 5(d), unimpregnated melamine resin 54 remaining on the white solid layer side surface of the sample S was scraped and removed with a metal plate 53.
6) As shown in FIG. 5(e), the sample S was dried for
1. 1 minute at 80°C, and then, the mass was measured again (the mass of the sample after the test).

The amount (g/m²) of the melamine resin impregnated into the decorative sheet was calculated from the following formula, and evaluated based on the following evaluation criteria. The results are shown in Table 1. $\begin{array}{l} Impregnated amount of melamine resin (g / m^{2}) = \{\begin{array}{l} sample \\ mass after test (g) - sample before test (g) \end{array}\} / opening \\ portion area of container (m^{2}) \end{array}$

• Evaluation criteria

A: The impregnated amount of the melamine resin was 45 g/m² or more
B: The impregnated amount of the melamine resin was 35 g/m² or more and less than 45 g/m²
C: The impregnated amount of the melamine resin was less than 35 g/m²

[Table 1]

	Example 1	Example 2	Example 3	Example 4	Example 5	Comp. Ex. 1	Comp. Ex. 2	Comp. Ex. 3	Comp. Ex. 4
White solid layer [µm]	2	6	1	2	2	0	2	2	2
White pigment	Titanium oxide	Titanium oxide	Titanium oxide	Titanium oxide	Titanium oxide	None	None	Titanium oxide	Titanium oxide
Ash content ratio [%]	30.6	32.1	29.3	33.8	23.4	28.4	28.5	19.4	40.4
L * value (decorative sheet)	94.6	95.2	93.9	96.4	93.3	92.6	92.0	89.6	96.8
L * value (decorative plate)	90.1	90.5	89.2	91.4	88.6	87.1	86.9	81.5	92.8
b * value (decorative sheet)	3.47	3.10	3.87	3.02	4.43	5.94	5.90	5.02	2.97
b * value (decorative plate)	3.35	3.12	4.06	3.08	4.25	4.67	4.59	4.55	2.92
Gloss value at 75° (decorative sheet)	12.6	16.8	8.7	20.2	7.8	4.5	4.9	5.6	25.4
Pure water contact angle [°]	35.1	70.3	31.7	28.8	44.8	22.8	36.1	78.4	23.6
Wettability [mN/m]	70	54	70	70	67	70	70	50	70
Impregnation amount [g/m²]	49	44	56	52	46	61	47	41	58
White designability	A	A	B	A	B	C	C	C	A
Gloss matte designability	A	A	A	B	A	B	A	A	C
Impregnation property	A	B	A	A	A	A	A	B	A

As shown in Table 1, the melamine decorative plate having good white designability and gloss matte designability can be produced with the decorative sheets in Examples 1 to 5. Meanwhile, the white designability of the melamine decorative plate produced using the decorative sheet wherein the solid layer was not disposed, as in Comparative Example 1, was low. Similarly, the white designability of the melamine decorative plate produced using the decorative sheet wherein the transparent solid layer including no white pigment, as in Comparative Example 2, was also low. Although the white solid layer was disposed in Comparative Example 3, the white designability of the melamine decorative plate was low, since the ash content of the decorative sheet was low. The gloss matte designability was low in Comparative Example 4, since the ash content of the decorative sheet was high so that the ink for a releasing layer permeated.
As described above, in the present disclosure, for example, the following inventions are provided.

[1] A decorative sheet used for a production of a resin-impregnated decorative plate, the decorative sheet comprising:
- a porous substrate;
- a white solid layer disposed on an entire surface of one surface of the porous substrate, and including a white pigment;
- a pattern layer disposed partially on a surface of the white solid layer that is opposite side to the porous substrate; and
- a releasing layer disposed in a pattern on a surface of the pattern layer that is opposite side to the white solid layer, wherein
- the white solid layer includes a white blank region not covered with the pattern layer;
- an L* value of the white blank region is 93.0 or more; and
- an ash content included in the decorative sheet is 20.0% by mass or more and 40.0% by mass or less.
[2] The decorative sheet according to [1], wherein the white pigment includes at least one of titanium oxide and calcium carbonate.
[3] The decorative sheet according to [1] or [2], wherein the thickness of the white solid layer is 1 µm or more and 8 µm or less.
[4] The decorative sheet according to any one of [1] to [3], wherein the porous substrate includes titanium paper.
[5] The decorative sheet according to any one of [1] to [4], wherein the ash content included in the decorative sheet is 22.0% by mass or more and 30.0% by mass or less.
[6] The decorative sheet according to any one of [1] to [5], wherein, in the decorative sheet, a b* value of the white blank region is 4.50 or less.
[7] The decorative sheet according to any one of [1] to [6], wherein, in the decorative sheet, a gloss value of the white blank region at 75° is 6.0 or more.
[8] The decorative sheet according to any one of [1] to [7], wherein, in the decorative sheet, a contact angle with respect to pure water, of a region exposed from the releasing layer, as view from a thickness direction, is 80.0° or less.
[9] The decorative sheet according to any one of [1] to [8], wherein, in the decorative sheet, a wettability of a region exposed from the releasing layer, as view from a thickness direction, is 50 mN/m or more.
[10] The decorative sheet according to any one of [1] to [9], wherein the white solid layer further includes resin component, and as the resin component, the white solid layer includes resin including a polar group.
[11] The decorative sheet according to [10], wherein a ratio of the resin including a polar group, with respect to the resin component included in the white solid layer, is 20% by mass or more and 100% by mass or less.
[12] The decorative sheet according to any one of [1] to [11], wherein the resin-impregnated decorative plate is a melamine decorative plate.
[13] The decorative sheet according to any one of [1] to [12], wherein the releasing layer includes a cured product of curable resin X.
[14] The decorative sheet according to [13], wherein the curable resin X is ionizing radiation curable resin.
[15] The decorative sheet according to [14], wherein the ionizing radiation curable resin is electron beam curable resin.
[16] A resin-impregnated decorative plate comprising:
- the decorative sheet according to any one of [1] to [15];
- a core substrate disposed so as to face the porous substrate of the decorative sheet; and
- a cured resin layer disposed on the white blank region, and including a cured product of curable resin Y, wherein
- the core substrate and the porous substrate include the cured product of the curable resin Y; and
- the L* value of the white blank region is 88.0 or more, when measured via the cured resin layer.

Reference Signs List

1: porous substrate
2: white solid layer
3: pattern layer
4: releasing layer
10: decorative sheet
20: core substrate
30: thermosetting resin layer
40: release film
100 resin-impregnated decorative plate

Claims

A decorative sheet used for a production of a resin-impregnated decorative plate, the decorative sheet comprising:
a porous substrate;

a white solid layer disposed on an entire surface of one surface of the porous substrate, and including a white pigment;

a pattern layer disposed partially on a surface of the white solid layer that is opposite side to the porous substrate; and

a releasing layer disposed in a pattern on a surface of the pattern layer that is opposite side to the white solid layer, wherein

the white solid layer includes a white blank region not covered with the pattern layer;

an L* value of the white blank region is 93.0 or more; and

an ash content included in the decorative sheet is 20.0% by mass or more and 40.0% by mass or less.
The decorative sheet according to claim 1, wherein the white pigment includes at least one of titanium oxide and calcium carbonate.
The decorative sheet according to claim 1, wherein the thickness of the white solid layer is 1 µm or more and 8 µm or less.
The decorative sheet according to claim 1, wherein the porous substrate includes titanium paper.
The decorative sheet according to claim 1, wherein the ash content included in the decorative sheet is 22.0% by mass or more and 30.0% by mass or less.
The decorative sheet according to claim 1, wherein, in the decorative sheet, a b* value of the white blank region is 4.50 or less.
The decorative sheet according to claim 1, wherein, in the decorative sheet, a gloss value of the white blank region at 75° is 6.0 or more.
The decorative sheet according to claim 1, wherein, in the decorative sheet, a contact angle with respect to pure water, of a region exposed from the releasing layer, as view from a thickness direction, is 80.0° or less.
The decorative sheet according to claim 1, wherein, in the decorative sheet, a wettability of a region exposed from the releasing layer, as view from a thickness direction, is 50 mN/m or more.
The decorative sheet according to claim 9, wherein the white solid layer further includes resin component, and as the resin component, the white solid layer includes resin including a polar group.
The decorative sheet according to claim 10, wherein a ratio of the resin including a polar group, with respect to the resin component included in the white solid layer, is 20% by mass or more and 100% by mass or less.
The decorative sheet according to claim 1, wherein the resin-impregnated decorative plate is a melamine decorative plate.
The decorative sheet according to claim 1, wherein the releasing layer includes a cured product of curable resin X.
The decorative sheet according to claim 13, wherein the curable resin X is ionizing radiation curable resin.
The decorative sheet according to claim 14, wherein the ionizing radiation curable resin is electron beam curable resin.
A resin-impregnated decorative plate comprising:
the decorative sheet according to any one of claims 1 to 15;

a core substrate disposed so as to face the porous substrate of the decorative sheet; and

a cured resin layer disposed on the white blank region, and including a cured product of curable resin Y, wherein

the core substrate and the porous substrate include the cured product of the curable resin Y; and

the L* value of the white blank region is 88.0 or more, when measured via the cured resin layer.