Release sheets and decorative materials

Abstract

The present invention provides a release sheet for use in decorative materials having a decorative body and an adherend, which are decorative sheets or decorative panels, that allows for easy separation of the adherend and the decorative body in the decorative material, and that enables the creation of a decorative material in which the adherend, the release sheet, and the decorative body are laminated with good adhesion during use, as well as a method for manufacturing the decorative material. [Solution] A release sheet is provided for use in a decorative material having a decorative body and an adherend, which is a decorative sheet or decorative board, wherein the release sheet has a base layer 1 which is paper and a barrier layer 2 which contains resin and is disposed on at least one surface of the base layer, the release sheet is a sheet disposed between the decorative body and the adherend in the thickness direction, the surface of the release sheet on the barrier layer side has a pure water contact angle of 120° or less, and the Rz (maximum height) as specified in JIS B0601:2013 is 4.0 μm or more and 10.0 μm or less.

Description

[Technical Field]

[0001] This disclosure relates to release sheets and decorative materials. [Background technology]

[0002] In recent years, with the advancement of recycling technologies, the recycling of waste materials is being widely promoted from the perspective of environmental protection and efficient resource utilization. Recycling technologies such as material recycling and chemical recycling are being promoted.

[0003] Traditionally, decorative materials have been used as building components. These decorative materials consist of a decorative element, such as a decorative sheet or panel, bonded to a substrate via an adhesive layer. In this case, the strong bond between the decorative element and the adhesive layer makes it difficult to separate the decorative element from the substrate. Therefore, separating the substrate from the decorative element becomes challenging. For these reasons, factory waste from decorative materials is often considered composite waste, and thermal recycling is the primary method of disposal. Similarly, demolition waste from buildings is often considered composite waste, and incineration and landfill are the primary methods of disposal.

[0004] Patent Document 1 discloses a decorative sheet in which, for the purpose of facilitating the separation and recovery of the base material and the decorative sheet, an unfoamed foam cohesive-breaking layer, in which a foaming agent is added to a resin binder, is laminated on the back side of the decorative sheet. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2004-017299 [Overview of the project] [Problems that the invention aims to solve]

[0006] The inventors of the present invention considered separating the adherend 3 from the decorative panel 6A by peeling the paper-based release layer 91 between the decorative panel 6A and the adherend 3, as shown in the decorative material 90 in Figure 11(a). The decorative material 90 shown in Figure 11(a) has a base 61, a porous substrate 62 and a decorative panel 6A having a design layer 63, a release layer 91, an adhesive layer 5, and an adherend 3, in this order. In the manufacturing process of such a decorative material, for example, a precursor of the decorative panel 6A and the release layer 91 are laminated with an adhesive layer in between as needed and then hot-pressed. During this hot-pressing, the resin contained in the layer above the release layer 91 (for example, the impregnating resin contained in the precursor of the decorative panel) penetrates into the release layer 91, causing the release layer 91 and the decorative panel 6A to become one, making it difficult to peel the paper-based release layer.

[0007] Furthermore, the inventors of the present application considered placing a paper release layer 91 between the decorative sheet 6B and the adherend 3, as shown in the decorative material 95 in Figure 11(b), and separating the adherend 3 and the decorative sheet 6B by paper-to-paper peeling of the release layer 91. The decorative material 95 has a decorative sheet 6B having a base layer 64 and a design layer 65, a first adhesive layer 4, a release layer 91, a second adhesive layer 5, and an adherend 3 in this order. In the manufacturing process of such a decorative material, for example, the decorative sheet 6B and the release layer 91 are laminated using a dry lamination method via the first adhesive layer 4. At this time, the adhesive resin of the first adhesive layer 4, which is laminated above the release layer 91, penetrates into the release layer 91, causing the release layer 91 and the decorative sheet 6B to become one, making paper-to-paper peeling at the release layer difficult. The adhesive resin refers to the resin used to form the adhesive layer. Furthermore, the adhesive resin of the second adhesive layer 5 may also penetrate into the release layer 91.

[0008] In response to the above problem, the inventors of the present application have found that a release sheet having paper and a barrier layer disposed on at least one surface of the paper can suppress the penetration of resin into the paper by the barrier layer, thereby enabling paper-to-paper peeling. However, as a result of further investigation, it has now been newly discovered that if the resin penetration suppression effect of the barrier layer is too high, the adhesion between the barrier layer in the release sheet and the decorative body or adhesive layer in contact with the barrier layer decreases. When the adhesion between the decorative body or adhesive layer and the release sheet decreases, spontaneous peeling may occur between the decorative body and the release sheet or between the adherend and the release sheet during use of the decorative material.

[0009] This disclosure has been made in view of the above circumstances, and aims to provide a release sheet for use in decorative materials having a decorative body and an adherend, which is a decorative sheet or decorative panel, that allows for easy separation of the adherend and the decorative body in the decorative material, and that enables the creation of a decorative material in which the adherend, the release sheet, and the decorative body are laminated with good adhesion during use. [Means for solving the problem]

[0010] This disclosure provides a release sheet for use in a decorative material having a decorative body which is a decorative sheet or decorative panel and an adherend, wherein the release sheet has a base layer which is paper and a barrier layer which contains resin and is disposed on at least one surface of the base layer, the release sheet is a sheet disposed between the decorative body and the adherend in the thickness direction, the surface of the release sheet on the barrier layer side has a pure water contact angle of 120° or less, and the Rz (maximum height) as defined in JIS B0601:2013 is 4.0 μm or more and 10.0 μm or less.

[0011] This disclosure provides a method for manufacturing a decorative material having a decorative panel and an adherend, comprising: a preparation step of preparing the above-mentioned release sheet and a decorative panel precursor containing a curable resin; a heating and pressurizing step of placing the decorative panel precursor and the surface of the release sheet on the barrier layer side facing each other, heating and pressurizing to cure the curable resin and obtain a cured laminate; and a bonding step of bonding the surface of the cured laminate on the release sheet side to the adherend to obtain the decorative material.

[0012] This disclosure provides a method for manufacturing a decorative material having a decorative sheet and an adherend, comprising: a preparation step of preparing the above-mentioned release sheet and the decorative sheet; a dry lamination step of placing the decorative sheet and the surface of the release sheet facing each other and bonding them together via an adhesive layer to obtain a laminate; and a bonding step of bonding the surface of the laminate facing the release sheet to the adherend to obtain the decorative material. [Effects of the Invention]

[0013] This disclosure provides a release sheet for use in a decorative material having a decorative body and an adherend, which is a decorative sheet or decorative panel, which allows for easy separation of the adherend and the decorative body in the decorative material, and provides a decorative material in which the adherend, release sheet, and decorative body are laminated with good adhesion during use. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic cross-sectional view illustrating the release sheet in this disclosure. [Figure 2] This is a schematic cross-sectional view illustrating an example of a cosmetic material in this disclosure. [Figure 3] These are cross-sectional views of the substrate near the surface, as well as cross-sectional views of the barrier layer side surface of the release sheet when Rz is large and when it is small. [Figure 4]It is a cross-sectional view near the surface on the barrier layer side of the release sheet in the present disclosure. [Figure 5] It is a schematic cross-sectional view illustrating a decorative material in the present disclosure. [Figure 6] It is a schematic cross-sectional view illustrating a decorative material in the present disclosure. [Figure 7] It is a schematic cross-sectional view illustrating a method for manufacturing a decorative material (First Embodiment) in the present disclosure. [Figure 8] It is a schematic cross-sectional view illustrating a cured laminate in the present disclosure. [Figure 9] It is a schematic cross-sectional view illustrating a method for manufacturing a decorative material (Second Embodiment) in the present disclosure. [Figure 10] It is a schematic cross-sectional view illustrating a decorative sheet in the present disclosure. [Figure 11] It is a schematic cross-sectional view of a decorative material in which a release layer is disposed between a decorative board and an adherent or between a decorative sheet and an adherent. [Figure 12] It is a schematic diagram for explaining a method for measuring the peel strength between papers.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments will be described with reference to the drawings and the like. However, the present disclosure can be implemented in many different modes and should not be limited to the description content of the embodiments illustrated below. Also, for the purpose of making the explanation clearer, the drawings may schematically represent the width, thickness, and shape of each part compared to the actual form, but this is merely an example and should not be construed as a limitation.

[0016] In this specification, when describing a configuration in which one member is placed on top of another member, the terms "on top" or "below" include, unless otherwise specified, both cases: one in which the other member is placed directly above or directly below the member so as to be in contact with it, and another in which the other member is placed above or below the member via yet another member. Similarly, when describing a configuration in this specification in which one member is placed on the surface of another member, the terms "on the surface" include, unless otherwise specified, both cases: one in which the other member is placed directly above or directly below the member so as to be in contact with it, and another in which the other member is placed above or below the member via yet another member.

[0017] A. Release sheet The release sheet in this disclosure is a release sheet used in a decorative material having a decorative body which is a decorative sheet or decorative board and an adherend, wherein the release sheet has a base layer which is paper and a barrier layer which contains resin and is disposed on at least one surface of the base layer, the release sheet is a sheet disposed between the decorative body and the adherend in the thickness direction, the surface of the release sheet on the barrier layer side has a pure water contact angle of 120° or less, and the Rz (maximum height) as defined in JIS B0601:2013 is 4.0 μm or more and 10.0 μm or less.

[0018] Figures 1(a) and 1(b) are schematic cross-sectional views illustrating a release sheet in this disclosure. Figures 2(a) to 2(d) are schematic cross-sectional views illustrating a decorative material in this disclosure. The release sheet 10 in Figure 1(a) has a base layer 1 and a barrier layer 2 containing resin, which is disposed on one surface 1a of the base layer 1. The release sheet 10 in Figure 1(b) has a base layer 1 and a first barrier layer 2a disposed on one surface 1a of the base layer 1 and a second barrier layer 2b disposed on the other surface 1b of the base layer.

[0019] The surface S1 of the release sheet 10 on the barrier layer 2 side, as shown in Figure 1(a), has a pure water contact angle of less than or equal to a predetermined value, and its Rz (maximum height) as defined in JIS B0601:2013 is within a predetermined range. Furthermore, the surface S1 on the first barrier layer 2a side and the surface S2 on the second barrier layer 2b side of the release sheet 10, as shown in Figure 1(b), have a pure water contact angle of less than or equal to a predetermined value, and their Rz (maximum height) as defined in JIS B0601:2013 is within a predetermined range.

[0020] The release sheet 10 in this disclosure is a release sheet used in a decorative material 100 having a decorative body 6 and an adherend 3, as shown in Figures 2(a) to 2(d), and has a thickness direction D T In this configuration, the release sheet is a sheet placed between the decorative body 6 and the adherend 3. As shown in Figures 2(a) to 2(c), it is preferable that the release sheet 10 is positioned so that the barrier layer 2 faces the decorative body 6. As shown in Figure 2(a), the surface S1 of the release sheet 10 on the barrier layer 2 side may be in contact with the decorative body 6. On the other hand, as shown in Figures 2(b) and 2(c), the surface S1 of the release sheet 10 on the barrier layer 2 side may be facing the decorative body 6 via the adhesive layer 4. Also, as shown in Figure 2(d), the release sheet 10 may be positioned so that the barrier layer 2 faces the adherend 3. As shown in Figure 2(d), the surface S1 of the release sheet 10 on the barrier layer 2 side may be facing the adherend 3 via the adhesive layer 5.

[0021] In this disclosure, the release sheet has a pure water contact angle on the surface of the barrier layer that is below a predetermined value, thereby moderately reducing the resin penetration suppression effect of the barrier layer. Therefore, during hot pressing or dry lamination in the manufacturing process of the decorative material, the impregnating resin or adhesive resin penetrates moderately into the substrate of the release sheet. As a result, a decorative material is obtained in which the adherend, release sheet, and decorative element are laminated with good adhesion, and spontaneous delamination between the decorative element and the release sheet, or between the adherend and the release sheet, during use of the decorative material can be suppressed. In this specification, the penetration of the impregnating resin into the substrate and the penetration of the adhesive resin into the substrate are also simply referred to as resin penetration.

[0022] In this disclosure, "the surface of the release sheet on the barrier layer side" refers to the surface of the release sheet located on the barrier layer side when the substrate layer is used as the reference. If the barrier layer is arranged on both sides of the substrate layer, it refers to each of the two surfaces of the release sheet.

[0023] Furthermore, the release sheet in this disclosure has a Rz (maximum height) on the surface on the barrier layer side that is within a predetermined range as defined in JIS B0601:2013. With such a release sheet, the barrier layer is applied appropriately to the substrate, so the penetration of the resin into the substrate is neither too high nor too low, but within an appropriate range. As a result, a decorative material is obtained in which the adherend, release sheet, and decorative element are laminated with good adhesion, and when peeling the decorative element from the adherend, paper-to-paper peeling is possible at the substrate. Consequently, after use of the decorative material, the decorative element can be easily separated from the adherend, improving recyclability.

[0024] Patent Document 1 discloses a method of separating the decorative sheet from the substrate by heating to foam a foamed cohesive failure layer laminated on the back side of the decorative sheet, then causing cohesive failure at the foamed cohesive failure layer to peel it off. Such a decorative sheet requires a high heat source, for example, because it is heated to 100°C or higher. Furthermore, the work efficiency is poor when peeling off large decorative materials, such as a 1m x 1m board. In contrast, decorative materials using the release sheet of this disclosure can be easily peeled off the adherend even at room temperature. The release sheet of this disclosure will be described in detail below.

[0025] 1. Physical properties of the release sheet (1) Pure water contact angle In this disclosure, the pure water contact angle of the barrier layer-side surface of the release sheet is typically 120° or less, preferably 115° or less, and more preferably 110° or less. If the pure water contact angle is too high, the impregnating resin and adhesive resin will have difficulty adhering to the barrier layer-side surface of the release sheet. As a result, the impregnating resin and adhesive resin will have difficulty penetrating into the substrate layer, reducing the adhesion between the barrier layer and the decorative body or adhesive layer in contact with the barrier layer, which may lead to spontaneous delamination between the release sheet and the decorative body, or between the release sheet and the adherend, during the use of the decorative material. On the other hand, the pure water contact angle may be, for example, 80° or more, and may also be 90° or more. Although the pure water contact angle is measured using pure water, it can actually be applied to all liquids other than water, and can also be applied to the evaluation of the wettability of resins melted at high temperatures or resins dissolved in solvents, etc.

[0026] The pure water contact angle is determined by the following method. First, the release sheet is placed on a horizontal surface with the barrier layer side facing upwards. Next, a drop of water (pure water, 2.0 μL) is dropped perpendicularly onto the barrier layer side of the release sheet. After dropping the water droplet, wait for 1 second and measure the contact angle between the barrier layer and the pure water using a contact angle meter. Perform the above measurement at any 10 locations and take the average value as the pure water contact angle. A fully automatic contact angle meter, "DMo-702, manufactured by Kyowa Interface Science Co., Ltd.," can be used as the contact angle meter.

[0027] The pure water contact angle of the barrier layer surface of the release sheet can be reduced to a predetermined value or less by, for example, adjusting the composition of the barrier layer composition. Specifically, the pure water contact angle can be reduced by, for example, lowering the crosslinking density of the resin forming the barrier layer. A more specific method for lowering the crosslinking density is to reduce the amount of curing agent containing isocyanate added to the thermosetting resin when the resin forming the barrier layer is a thermosetting resin. The pure water contact angle can also be reduced by reducing the content of highly water-repellent resins such as silicone resins and fluororesins.

[0028] (2) Rz (maximum height) In this disclosure, the release sheet has a maximum height (Rz) of the barrier layer side surface, as defined in JIS B0601:2013, that is typically 4.0 μm or more, preferably 4.5 μm or more, and more preferably 5.0 μm or more. On the other hand, the maximum height (Rz) is typically 10.0 μm or less, preferably 9.0 μm or less, and more preferably 8.5 μm or less.

[0029] Figure 3(a) is a schematic cross-sectional view of the substrate without a laminated barrier layer, Figures 3(b) and 3(c) are cross-sectional views of the release sheet when the Rz of the surface on the barrier layer side of the release sheet is large (Rz > 10.0 μm), and Figure 3(d) is a cross-sectional view of the release sheet when the Rz of the surface on the barrier layer side of the release sheet is small (Rz < 4.0 μm).

[0030] As shown in Figure 3(a), the base layer 1 is paper and therefore typically has an uneven surface. When the barrier layer is not laminated, the resin penetrates highly at any point on the surface of the base layer, causing excessive penetration of the impregnation resin and adhesive resin. As a result, delamination between the paper layers becomes difficult after dry lamination or heat pressing. In other words, even if the Rz of the base layer surface is within the above range, delamination between the paper layers cannot be achieved. Therefore, in the present invention, it is important that the Rz of the surface on the barrier layer side of the release sheet is within the above range.

[0031] As shown in Figure 3(b), if the Rz value on the surface of the release sheet 10 on the barrier 2 layer side is too large, it is assumed that a large amount of barrier layer 2 is laminated on the convex parts of the base layer 1, and that the barrier layer is not sufficiently laminated on the concave parts of the base layer 1. Also, as shown in Figure 3(c), it is also assumed that the surface of the base layer 1 is too rough, so that the barrier layer 2 is not sufficiently laminated on the concave parts of the base layer 1. In either case, the uneven shape of the surface on the barrier layer side of the release sheet is locally pronounced, and there are many areas where the base layer is exposed. Consequently, the impregnating resin and adhesive resin penetrate excessively into the base layer, and while adhesion between the barrier layer of the release sheet and the decorative body or adhesive layer in contact with the barrier layer is achieved, peeling between the paper layers in the base layer becomes difficult. Thus, even if the amount (thickness) of the barrier layer is large, penetration may not be suppressed.

[0032] As shown in Figure 3(d), the Rz value on the surface of the release sheet 10 on the barrier layer 2 side is too small, which suggests that the amount of barrier layer 2 applied was increased to fill the depressions in the base layer 1, and that the surface of the barrier layer 2 was made too smooth. As a result, the barrier layer covers most of the surface of the base layer, and the area where the impregnating resin and adhesive resin can penetrate is limited, so resin penetration cannot be ensured. Consequently, sufficient adhesion cannot be obtained between the decorative object and the release sheet, or between the adherend and the release sheet.

[0033] On the other hand, in the release sheet in this disclosure, the Rz on the surface on the barrier layer side is within a predetermined range. Figure 4 is a cross-sectional view of the vicinity of the barrier layer side surface S of the release sheet in this disclosure. As shown in Figure 4, the state in which the Rz on the surface on the barrier layer side is within a predetermined range is presumed to mean that the barrier layer 2 is appropriately laminated even in the recesses of the substrate layer 1 (the substrate layer 1 is appropriately exposed), regardless of the amount (thickness) of the barrier layer 2 applied and the unevenness of the surface of the substrate layer 1. Therefore, the impregnating resin or adhesive resin penetrates the substrate appropriately, and a decorative material is obtained in which the adherend, release sheet and decorative material are laminated with good adhesion, and after use of the decorative material, paper peeling is possible at the substrate layer.

[0034] The Rz (maximum height) on the barrier layer side surface is determined according to JIS B0601:2013 and is obtained by the following method. The Rz (maximum height) is measured at 10 arbitrary locations on the barrier layer side surface of the release sheet measurement sample using a surface roughness meter under the following detector and measurement conditions. This measurement is performed at 10 arbitrary locations, and the average value is taken as the Rz (maximum height). The "SurfCorder SE800 (manufactured by Kosaka Laboratory)" surface roughness meter can be used.

[0035] (Detector conditions) • Detection method: differential transformer ·Measuring force: 0.75mN • Stylus shape: Tip radius 2μm ±25%, apex angle 60°, made of diamond. • Skid: Radius of curvature 40mm (measurement direction), made of sapphire.

[0036] (Measurement conditions) • Vertical magnification: ×2000 (resolution: 10nm, detection range: ±300μm) ·Measurement speed…0.5mm / s • Standard used: JIS B 0601:2013 (ISO 4287:1997, Amd.1:2009) • Cutoff value λc (λc contour curve filter)...0.8mm • Cutoff value λs (λs contour curve filter)...2.5 μm • Cutoff filter characteristics: Gaussian filter • Evaluation length: 4.0 mm (λc × 5 times) • Spare length: 0.8mm (λc × 1x) • Data interval: Processed at intervals of cutoff length λc (divided into 1600 equal parts per cutoff length). • Roughness data calculation method: Calculated for each cutoff length λc (= 5 points of value are obtained), The average of 5 points is used as the numerical value for that measurement. • Measurement locations: 10 locations

[0037] In this disclosure, the Rz of the surface on the barrier layer side of the release sheet can be brought within a predetermined range, for example, by adjusting the composition of the barrier layer composition. Specifically, Rz can be adjusted by adjusting the type of resin and particles in the barrier layer composition, the average particle size and content of the particles, etc. Furthermore, Rz can also be brought within a predetermined range by adjusting the application method and number of applications of the barrier layer composition, the viscosity of the barrier layer composition, etc.

[0038] (3) Ra (Arithmetic mean roughness) In this disclosure, the release sheet has an arithmetic mean roughness (Ra) on the surface facing the barrier layer, as defined in JIS B0601:2013, of, for example, 0.5 μm or more, preferably 0.6 μm or more, and more preferably 0.7 μm or more. On the other hand, the above Ra (arithmetic mean roughness) is preferably 1.2 μm or less, and more preferably 1.0 μm or less. Because the Ra on the surface facing the barrier layer is within the above range, the release sheet 10 tends to be such that the barrier layer 2 is appropriately laminated even in the recesses of the substrate layer 1, as shown in Figure 4.

[0039] (4) Paper-to-paper peel strength The paper-to-paper peel strength of the release sheet in this disclosure is, for example, 1500 mN / 15 mm or less, preferably 1000 mN / 15 mm or less, and more preferably 800 mN / 15 mm or less. Having a paper-to-paper peel strength within the above range makes it easier to peel the release sheet from the underlying layer when used in decorative materials, allowing for easy separation of the adherend and the decorative material.

[0040] On the other hand, the inter-paper peel strength of the release sheet is preferably 100 mN / 15 mm or more, more preferably 150 mN / 15 mm or more, and more preferably 200 mN / 15 mm or more. By having the inter-paper peel strength within the above range, it is possible to suppress the occurrence of inter-paper peeling due to deterioration over time when actually used as a decorative material, which can cause the decorative material to peel off the adherend.

[0041] The inter-paper peel strength of the release sheet is the value measured by the following measurement method. (Method for measuring paper peel strength) As shown in Figure 12(a), Nichiban's cellophane tape (registered trademark) 71 is attached to both sides of the release sheet 10 to prepare a sample X for measuring the inter-paper peel strength. As shown in Figure 12(b), the measurement sample X is subjected to a peel test in the T-type peeling manner under the following conditions, and the integral average load of the peel strength is defined as the peel strength. • Peeling width: 15mm • Peeling distance: 20mm • Peeling speed: 100 mm / min

[0042] In release sheets, the base layer typically contains the resin included in the barrier layer, which allows the base layer and barrier layer to adhere closely together and be laminated. Furthermore, if the barrier layer contains inorganic particles, it is preferable that these inorganic particles are not contained within the base layer but are instead deposited near the surface of the barrier layer on the base layer side. The above-described state of the release sheet can be confirmed by cross-sectional observation using SEM-EDX.

[0043] 2. Layer composition of the release sheet The release sheet in this disclosure comprises a base layer 1 which is paper, and a barrier layer 2 which is disposed on one side of the base layer 1 and contains resin. The release sheet in this disclosure may have a configuration in which the barrier layer 2 is on one side of the base layer 1, as shown in Figure 1(a), or it may have a configuration in which the barrier layer 2 (first barrier layer 2a and second barrier layer 2b) is on both sides of the base layer 1, as shown in Figure 1(b).

[0044] (1) Base layer The release sheet in this disclosure has a paper base layer. The base layer is a layer that allows the adhesion between the decorative object and the adherend to be maintained when the release sheet is used as a decorative material, and also allows the decorative object and the adherend to be separated by paper delamination (a phenomenon in which delamination occurs in the paper layer).

[0045] (a) Paper The type of paper used as the underlying layer in this disclosure is not particularly limited, as long as it is peelable between layers. In this specification, "paper" means "a material manufactured by bonding plant fibers or other fibers together" as defined in the Japanese Industrial Standards (JIS).

[0046] Paper typically contains fibrous material. In this disclosure, it is preferable that the paper contains plant fibers as the fibrous material. This is because it has a low environmental impact and makes it easy to adjust the peel strength between sheets to the range described below. The fibrous material may also contain synthetic fibers, metal fibers, etc.

[0047] Examples of plant fibers include wood pulp and non-wood pulp made from hemp, cotton, and straw. Examples of wood pulp include chemical pulp, semi-chemical pulp, and mechanical pulp. The tree species can be either coniferous or broadleaf trees. Examples of chemical pulp include kraft pulp and sulfite pulp. The paper in this disclosure may contain one or more types of plant fibers. Synthetic pulp, rayon fibers, synthetic fibers, glass fibers, etc., can also be used in combination, and biodegradable materials can also be used.

[0048] In this disclosure, the paper includes the above-mentioned fibrous material, but may also include fillers, paper strength enhancers, sizing agents, etc., as necessary.

[0049] Examples of paper strength enhancers include polyacrylamide, epoxy polyamide, cationized starch, and carboxymethylcellulose. The content of the paper strength enhancer is not particularly limited.

[0050] Examples of sizing agents include internal sizing agents such as rosin sizing agents, synthetic sizing agents, and petroleum resin-based sizing agents, as well as surface sizing agents such as styrene / acrylic acid copolymers and styrene / methacrylic acid copolymers. The content of the sizing agent is not particularly limited.

[0051] Examples of fillers include inorganic fillers such as talc, kaolin, calcined kaolin, calcium carbonate, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, alumina, magnesium carbonate, magnesium oxide, silica, white carbon, bentonite, zeolite, sericite, and smectite, as well as organic fillers such as acrylic resins and vinylidene chloride resins.

[0052] Examples of papers containing plant fibers include wallpaper backing paper used in various types of decorative papers, fine paper, tissue paper, kraft paper, linter paper, parchment paper, glassine paper, sulfuric acid paper, etc., or mixed papers made by mixing glass fibers or resin fibers into these papers.

[0053] Examples of backing paper include paper made by papermaking using known bleached kraft pulp from softwood (NBKP), bleached kraft pulp from hardwood (LBKP), crushed wood pulp (GP), thermomechanical pulp (TMP), and chemothermetic pulp (CTMP), either individually or in any proportion. Furthermore, synthetic fibers such as polyester resin fibers including polyethylene terephthalate, polyolefin resin fibers including polypropylene and polyethylene, polyamide resin fibers including nylon, and halogen-containing resin fibers including polyvinyl chloride may be blended with these wood fibers.

[0054] (b) Pure water contact angle The base layer has a pure water contact angle on the surface where the barrier layer is provided, for example, 120° or less, preferably 115° or less, and more preferably 110° or less. Having the pure water contact angle of the base layer within this range tends to result in good adhesion between the base layer and the barrier layer. On the other hand, the pure water contact angle may be, for example, 10° or more, and may also be 20° or more. Having the pure water contact angle of the base layer within this range suppresses resin penetration during barrier layer formation, making it easier to adjust the Ra and Rz values ​​of the barrier layer side surface of the release sheet to the aforementioned values.

[0055] The pure water contact angle of the surface on which the barrier layer of the underlying layer is provided is a value measured with respect to the surface of the underlying layer using the same method as the method for measuring the pure water contact angle of the release sheet described above.

[0056] (c) Size The paper in this disclosure preferably has a size degree measured according to JIS P 8122 of, for example, 10 seconds or more, and more preferably 20 seconds or more.

[0057] Because the size degree is within the above range, the penetration of resin during barrier layer formation is suppressed, making it easier to adjust the Rz and Ra of the barrier layer side surface of the release sheet to within the above range.

[0058] On the other hand, the above sizing interval is, for example, 60 seconds or less, and preferably 40 seconds or less. By keeping the sizing interval within the above range, there is no risk of excessive suppression of resin penetration, such as the resin, adhesive resin, and impregnation resin contained in the barrier layer described later, and a decrease in adhesion between the substrate layer and the barrier layer, and a decrease in adhesion between the decorative body or adherend and the release sheet can be suppressed.

[0059] In this disclosure, the paper size is a value measured based on the test method specified in JIS P 8122:2004 (Steckhit method). The principle of the Steckhit method is as follows: First, a test piece is floated in an aqueous solution of ammonium thiocyanate, and a droplet of an aqueous solution of iron(III) chloride is placed on the test piece. Each aqueous solution penetrates into the paper, and upon contact and reaction, iron thiocyanate is produced, resulting in a red color. Therefore, the time required for penetration can be easily measured by observing the color change.

[0060] (Method for measuring size) The specific method for measuring the size degree in this disclosure shall be carried out under the standard conditions specified in JIS P 8111. First, the test piece (paper) is floated in an ammonium thiocyanate aqueous solution at 23±1°C in a petri dish. The test piece (paper) is folded in advance on all four sides so that the ammonium thiocyanate aqueous solution does not come into contact with the top surface of the test piece. Immediately, using a pipette, one drop of 1% iron(III) chloride aqueous solution at the same temperature is dropped onto the test piece, and the time until three red spots appear in the drop is measured in 0.1-second increments using a stopwatch. This operation is performed 5 times on each side of the test piece, for a total of 10 times. The average value of the 10 measurements is calculated and used as the size degree value.

[0061] (d)Basic weight The basis weight of the paper in this disclosure is 30 g / m². 2 Preferably, it is 50 g / m 2 It is more preferable that the above conditions are met. If the basis weight of the paper is within the above range, stable inter-paper release properties can be obtained. On the other hand, the basis weight of the paper is 100 g / m². 2 Preferably, it is 80 g / m 2The following is more preferable. If the basis weight of the paper is within the above range, effects such as cost reduction and improved processability when laminating to the substrate can be expected.

[0062] (e) thickness In this disclosure, the thickness of the underlayment is preferably 60 μm or more, and more preferably 80 μm or more. If the thickness of the underlayment is within the above range, stable paper-to-paper release properties can be obtained. On the other hand, the thickness of the underlayment is preferably 120 μm or less, and more preferably 100 μm or less. If the thickness of the underlayment is within the above range, effects such as cost reduction and improved processability when laminating to the substrate can be expected.

[0063] (f) Rz (maximum height) The substrate layer preferably has a surface Rz (maximum height) of 20.0 μm or less, and more preferably 18.0 μm or less. If the Rz of the surface of the substrate layer where the barrier layer is provided is too large, it may become difficult to laminate the barrier layer into the recesses of the substrate layer, and the Rz of the surface of the release sheet on the barrier layer side tends to be larger than the above range. On the other hand, the above Rz (maximum height) may be, for example, 4.0 μm or more, and may also be 6.0 μm or more.

[0064] The Rz (maximum height) of the surface on which the barrier layer of the underlying layer is provided is the value measured on the surface on which the barrier layer of the underlying layer is provided using the same measurement method as described above.

[0065] (g) Ra (Arithmetic mean roughness) The substrate layer preferably has an arithmetic mean roughness (Ra) of 4.0 μm or less on the surface where the barrier layer is provided, and more preferably 3.5 μm or less. If the Ra of the surface of the substrate layer where the barrier layer is provided is too high, it may become difficult to laminate the barrier layer into the depressions of the substrate layer. On the other hand, the above Ra (arithmetic mean roughness) may be, for example, 0.5 μm or more, and may also be 0.7 μm or more.

[0066] The Ra (arithmetic mean roughness) of the surface on which the underlying barrier layer is provided is the value measured on the surface on which the underlying barrier layer is provided using the same measurement method as described above.

[0067] (2) Barrier layer The release sheet in this disclosure is disposed on one side of the substrate layer and has a barrier layer containing resin. The barrier layer is a layer that suppresses resin penetration into the substrate layer and imparts paper-to-paper release properties to the substrate layer.

[0068] (a) Material The barrier layer contains a resin. Examples of resins include cured products of ionizing radiation-curable resins and cured products of thermosetting resins.

[0069] Ionizing radiation-curable resins are compositions containing compounds having ionizing radiation-curable functional groups (ionizing radiation-curable compounds) that harden upon exposure to ionizing radiation. Ionizing radiation refers to electromagnetic waves or charged particle beams that have energy quanta capable of polymerizing or crosslinking molecules. While ultraviolet (UV) or electron beams (EB) are typically used as ionizing radiation, other electromagnetic waves such as X-rays and gamma rays, or charged particle beams such as alpha rays and ion beams may also be used. Ionizing radiation-curable resins may also be UV-curable resins or electron beam-curable resins.

[0070] Ionizing radiation-curable functional groups are groups that undergo crosslinking hardening upon irradiation with ionizing radiation. Examples include functional groups having ethylenic double bonds, such as (meth)acryloyl groups, vinyl groups, and allyl groups. Other examples of ionizing radiation-curable functional groups include epoxy groups and oxetanyl groups. A (meth)acryloyl group refers to either an acryloyl group or a metacloyl group. A (meth)acrylate refers to either an acrylate or a methacrylate.

[0071] Ionizing radiation-curable compounds are preferably compounds having two or more ethylenically unsaturated bonding groups. In particular, ionizing radiation-curable compounds are preferably polyfunctional (meth)acrylate compounds having two or more ethylenically unsaturated bonding groups. Polyfunctional (meth)acrylate compounds may be monomers, oligomers, or polymers.

[0072] Examples of bifunctional (meth)acrylate monomers include urethane acrylate, ethylene glycol di(meth)acrylate, bisphenol A tetraethoxydiacrylate, bisphenol A tetrapropoxydiacrylate, and 1,6-hexanediol diacrylate. On the other hand, examples of trifunctional (meth)acrylate monomers include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and isocyanuric acid-modified tri(meth)acrylate.

[0073] Examples of polyfunctional (meth)acrylate oligomers include urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and polyether (meth)acrylate. Urethane (meth)acrylate can be obtained, for example, by the reaction of polyhydric alcohols and organic diisocyanates with hydroxy (meth)acrylate.

[0074] When the ionizing radiation-curable resin is an ultraviolet-curable resin, it is preferable that the ionizing radiation-curable resin contains additives such as photopolymerization initiators and photopolymerization accelerators. Examples of photopolymerization initiators include acetophenone, benzophenone, α-hydroxyalkylphenone, Michler ketone, benzoin, benzyldimethyl ketal, benzoylbenzoate, α-acyloxime esters, and thioxanthones. Examples of photopolymerization accelerators include isoamyl p-dimethylaminobenzoate and ethyl p-dimethylaminobenzoate.

[0075] Thermosetting resins are resins that harden with heat. Examples of thermosetting resins include acrylic polyol resins, (meth)acrylic resins, urethane resins, phenolic resins, urea-melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins. When forming a barrier layer using a resin composition containing a thermosetting resin, the resin composition may optionally contain at least one of a curing agent and a curing catalyst. Examples of curing agents include isocyanate-based curing agents and epoxy-based curing agents.

[0076] Other resins that can be used in the barrier layer include, for example, acrylic acrylate resins, urethane acrylate resins, polycarbonate resins, polyethylene terephthalate resins, vinyl chloride-vinyl acetate copolymer resins, polypropylene resins, and other olefin resins. These can be used individually or in combination.

[0077] Among these, resins with heat resistance are preferred, specifically resins with a glass transition temperature (Tg) of 50°C or higher are preferred, resins with a Tg of 70°C or higher are more preferred, and resins with a Tg of 90°C or higher are particularly preferred. Note that the above glass transition temperature is the glass transition temperature of the resin alone before it is compounded as an ink (barrier layer composition). In the lamination process with the decorative body or adherend, the release sheet may be heated during hot pressing, high-temperature adhesive application, and adhesive drying. Therefore, if the barrier layer has a resin with low heat resistance, there is a possibility that the adhesive resin or impregnation resin may penetrate excessively into the substrate layer. Examples of heat-resistant resins include acrylic polyol resins, polycarbonate resins, polypropylene resins, and polyethylene terephthalate resins. In particular, considering the ease of barrier layer formation and the adhesion between the adhesive resin and impregnation resin to the barrier layer, in addition to heat resistance, acrylic polyol resins are preferred.

[0078] The barrier layer may contain additives as needed. Examples of additives include inorganic particles and silicone oil, as described later.

[0079] The barrier layer preferably contains inorganic particles. This is because it prevents the blocking phenomenon that occurs when the underlayer with the barrier layer already formed is stacked or wound up during the barrier layer formation process described later. The inorganic particles may also function as a dispersant or defoamer in the ink state. Examples of inorganic particles include silica, aluminum hydroxide, and calcium carbonate.

[0080] The average particle size of inorganic particles is, for example, 20 μm or less, and preferably 10 μm or less. On the other hand, the average particle size of inorganic particles may be, for example, 1 μm or more, and may be 3 μm or more. The average particle size refers to d50, which is the volume-based particle size distribution measured by laser diffraction scattering.

[0081] The inorganic particle content is preferably 5 parts by mass or more and 60 parts by mass or less, and more preferably 10 parts by mass or more and 50 parts by mass or less, per 100 parts by mass of the resin component.

[0082] (b) thickness The thickness of the barrier layer is preferably 3 μm or more, more preferably 5 μm or more, and particularly preferably 7 μm or more. On the other hand, the thickness of the barrier layer is preferably 25 μm or less, more preferably 20 μm or less, and even more preferably 17 μm or less.

[0083] The thickness of the barrier layer is determined by using the optical mode of a Keyence laser microscope "VKX1000 (control unit) / VKX1050 (measurement unit)" with a 20x objective lens to observe the cross-section of the barrier layer, and taking the average of 20 arbitrary measurement points.

[0084] (c) Formation method The method for forming the barrier layer is not particularly limited, but one method involves coating one surface of the substrate with the barrier layer composition containing the resin, and then drying and curing it as needed. Examples of known methods for coating the barrier layer composition include gravure printing, bar coating, roll coating, reverse roll coating, and comma coating. As the coating method, a gravure printing method in one or more steps is preferred.

[0085] The barrier layer composition contains, for example, the resin, additives, and solvents mentioned above.

[0086] 3. Uses of release sheets The release sheet in this disclosure is a release sheet used in a decorative material having a decorative body and an adherend, which are decorative sheets or decorative panels. Preferably, the release sheet in this disclosure is used with the surface facing the barrier layer facing the decorative body. This is because the penetration of the impregnating resin contained in the decorative panel precursor into the substrate layer is appropriately suppressed during hot pressing in the manufacturing of the decorative material. Also, during dry lamination in the manufacturing of the decorative material, the penetration of the resin of the adhesive layer placed between the decorative body and the release sheet into the substrate layer is appropriately suppressed. On the other hand, the release sheet in this disclosure may be used with the surface facing the barrier layer facing the adherend. In this case, the penetration of the resin of the adhesive layer placed between the adherend and the release sheet into the substrate layer is appropriately suppressed during dry lamination in the manufacturing of the decorative material.

[0087] Figures 5 and 6 are schematic cross-sectional views illustrating decorative materials in this disclosure. The decorative material 100A shown in Figures 5(a) and 5(b) has a thickness direction D T In this configuration, the adherend 3, the release sheet 10, and the decorative panel 6A are arranged in this order. The decorative panel 6A is, for example, in the thickness direction D T In this configuration, the release sheet 10 side has a base 61, a porous substrate 62, and a decorative layer 63 in that order. Here, the decorative material 100A shown in Figures 5(a) and 5(b) has a barrier layer 2 between the base layer 1 and the decorative panel 6A.

[0088] In the decorative material 100A shown in Fig. 5(a), the surface S1 on the barrier layer 2 side of the release sheet 10 is in contact with the decorative board 6A. With such a decorative material, the barrier layer 2 in the release sheet 10 appropriately suppresses the penetration of the impregnated resin of the substrate 61 and the porous base material 62 into the base layer 1. Therefore, it becomes easy to peel between papers in the base layer 1, and the decorative material 100A has good adhesion between the release sheet 10 and the decorative board 6A. In the decorative material 100A shown in Fig. 5(a), since the barrier layer is not arranged on the surface on the base layer 1 side of the release sheet 10, the adhesion with the adhesive layer 5 is good. Therefore, the decorative material 100A is formed by laminating the adherend 3, the release sheet 10, and the decorative board 6A with good adhesion. Also, in the present disclosure, if the release sheet 10 appropriately suppresses the penetration of the impregnated resin or the adhesive resin into the base layer from at least one surface side, it becomes easy to peel between papers in the base layer 1.

[0089] In the decorative material 100A shown in Fig. 5(b), the surface S1 on the barrier layer 2 side of the release sheet 10 is in contact with the first adhesive layer 4. With such a decorative material, the barrier layer 2 in the release sheet 10 appropriately suppresses the penetration of the adhesive resin of the first adhesive layer 4 into the base layer 1. Therefore, it becomes easy to peel between papers in the base layer 1, and the decorative material 100A has good adhesion between the release sheet 10 and the decorative board 6A. In the decorative material 100A shown in Fig. 5(b), the surface on the base layer 1 side of the release sheet 10 has good adhesion with the adhesive layer 5. Therefore, the decorative material 100A is formed by laminating the adherend 3, the release sheet 10, and the decorative board 6A with good adhesion.

[0090] The decorative material 100B shown in Fig. 5(c) has, in the thickness direction D T the adherend 3, the release sheet 10, and the decorative sheet 6B in this order. The decorative sheet 6B, for example, in the thickness direction D TIn this configuration, the base layer 64 and the decorative layer 65 are arranged in this order from the release sheet 10 side. Here, the decorative material 100B shown in Figure 5(c) has a barrier layer 2 between the base layer 1 and the decorative sheet 6B, and the surface S1 of the release sheet 10 on the barrier layer 2 side is in contact with the first adhesive layer 4. With such a decorative material, the barrier layer 2 in the release sheet 10 moderately suppresses the penetration of the adhesive resin of the adhesive layer (first adhesive layer 4) into the base layer 1. As a result, peeling between the paper layers in the base layer 1 becomes easy, and the decorative material 100B has good adhesion between the release sheet 10 and the decorative sheet 6B. In addition, in the decorative material 100B shown in Figure 5(c), the surface of the release sheet 10 on the base layer 1 side has good adhesion with the adhesive layer 5. As a result, the adherend 3, release sheet 10 and decorative sheet 6B are laminated with good adhesion to the decorative material 100A.

[0091] In the decorative material 100A shown in Figure 6(a), the surface S1 of the release sheet 10 facing the barrier layer 2 is in contact with the decorative panel 6A. Furthermore, in the decorative material 100A shown in Figure 6(a), the surface S2 of the release sheet 10 facing the barrier layer 2 is in contact with the second adhesive layer 5. In addition, in the decorative material 100A shown in Figure 6(b), the surface S1 of the release sheet 10 facing the barrier layer 2 is in contact with the first adhesive layer 4. Furthermore, in the decorative material 100A shown in Figure 6(b), the surface S2 of the release sheet 10 facing the barrier layer 2 is in contact with the second adhesive layer 5. With the decorative materials shown in Figures 6(a) and 6(b), the barrier layer 2 in the release sheet 10 appropriately suppresses the penetration of the impregnating resin of the substrate 61 and porous substrate 62 into the base layer 1, as well as the penetration of the adhesive resin of the first adhesive layer 4 and second adhesive layer 5 into the base layer 1. Therefore, peeling between the paper layers in the base layer 1 becomes easier, and the adhesion between the adherend 3, the release sheet 10, and the decorative panel 6A in the decorative material 100A is improved.

[0092] In the decorative material 100B shown in Figure 6(c), the surface S1 of the release sheet 10 facing the barrier layer 2 is in contact with the first adhesive layer 4. Furthermore, in the decorative material 100B shown in Figure 6(c), the surface S2 of the release sheet 10 facing the barrier layer 2 is in contact with the second adhesive layer 5. With the decorative material shown in Figure 6(c), the barrier layer 2 in the release sheet 10 moderately suppresses the penetration of the adhesive resin of the first adhesive layer 4 and the second adhesive layer 5 into the substrate layer 1. As a result, peeling between the paper layers in the substrate layer 1 becomes easier, and the adhesion between the adherend 3, the release sheet 10, and the decorative sheet 6B in the decorative material 100B is improved.

[0093] Examples of applications for the decorative materials in this disclosure include building components such as walls, ceilings, floors, roofs, eaves, fences, and gates; joinery or structural components such as window frames, doors, handrails, baseboards, moldings, and trim; general furniture such as chests of drawers, shelves, and desks; kitchen furniture such as dining tables and sinks; various furniture used in wet areas such as kitchens, toilets, bathrooms, and washbasins; surface decorative materials for cabinets of home appliances, office equipment, etc.; and interior or exterior components for vehicles. Furthermore, the decorative materials in this disclosure may be components used outdoors (exterior components) or components used indoors (interior components).

[0094] B. Manufacturing method of decorative materials The method for manufacturing the decorative material in this disclosure will be described as follows: when the decorative body is a decorative panel, it will be referred to as the decorative material of the first embodiment; when the decorative body is a decorative sheet, it will be referred to as the decorative material of the second embodiment.

[0095] I. First Embodiment Figure 7 is a schematic cross-sectional view illustrating a method for manufacturing a decorative material in this disclosure. As shown in Figure 7, the method for manufacturing a decorative material in this disclosure includes a preparation step (Figure 7(a)) of preparing the above-mentioned release sheet 10 and a decorative panel precursor 6A' containing a curable resin; a heating and pressing step (Figure 7(b)) of placing the decorative panel precursor 6A' and the surface S1 of the release sheet 10 on the barrier layer 2 side facing each other, heating and pressing to cure the curable resin and obtain a cured laminate 50; and a bonding step (Figure 7(c)) of bonding the surface of the cured laminate 50 on the release sheet 10 side to the adherend 3 to obtain the decorative material.

[0096] With the manufacturing method of the decorative material described in this disclosure, a decorative material is obtained in which the release sheet described above is placed between the decorative panel and the adherend in the thickness direction. For the reasons described above, such a decorative material allows for easy separation of the adherend and the decorative panel by delamination at the base layer of the release sheet, and the decorative panel exhibits good adhesion between the decorative panel and the release sheet during use.

[0097] (1) Preparation process (a) Release sheet The release sheet to be prepared in this process is the same as described in "A. Release Sheet" above, so its explanation is omitted here.

[0098] (b) Precursor of decorative panel As shown in Figure 7(a), the decorative laminate precursor 6A' prepared in this process has a thickness direction D T In this configuration, the substrate 61, porous substrate 62, and design layer 63 are arranged in this order. The substrate 61 and porous substrate 62 contain a curable resin X.

[0099] (i) Substrate Examples of substrates include porous core substrates. Examples of core substrates include phenol resin-impregnated paper. Phenolic resin-impregnated paper is a type of paper obtained by impregnating kraft paper, which is a core paper, with phenol resin and drying it.

[0100] (ii) Porous substrate Examples of porous substrates include permeable fibrous substrates. Examples of permeable fibrous substrates include paper, synthetic paper, nonwoven fabrics, and woven fabrics. Examples of the above-mentioned papers include titanium paper, tissue paper, kraft paper, linter paper, cardboard, gypsum board paper, fine paper, coated paper, parchment paper, and Japanese paper. In addition, vinyl wallpaper raw material (paper dry-laminated with polyvinyl chloride resin) can also be used as a fibrous substrate. Other examples of fibrous substrates include nonwoven or woven fabrics containing inorganic fibers such as glass fibers, asbestos, potassium titanate fibers, alumina fibers, silica fibers, and carbon fibers. Further examples of fibrous substrates include nonwoven or woven fabrics containing synthetic resin fibers such as polyester, vinylon, polyethylene, and polypropylene. Among these porous substrates, titanium paper, tissue paper, kraft paper, coated paper, art paper, sulfuric acid paper, glassine paper, parchment paper, paraffin paper, and Japanese paper are preferred in terms of their ability to impregnate with thermosetting resins.

[0101] Porous substrates may be colored. For example, a colored porous substrate can be obtained by incorporating a coloring agent during the manufacturing process of the porous substrate. For example, if the porous substrate is paper, colored paper can be obtained by incorporating a coloring agent during the papermaking process. Examples of coloring agents include inorganic pigments such as titanium dioxide, carbon black, and iron oxide, organic pigments such as phthalocyanine blue, and various dyes. The amount of coloring agent added is set appropriately according to the desired color. When a porous substrate contains a coloring agent, the porous substrate can also serve as a decorative layer, as described later.

[0102] Furthermore, the porous substrate may contain various additives as needed, such as fillers, matting agents, foaming agents, flame retardants, lubricants, antistatic agents, antioxidants, UV absorbers, and light stabilizers.

[0103] The basis weight of the porous substrate is not particularly limited, but for example, 40 g / m² 2 More than 150g / m 2The following applies: The thickness of the porous substrate is not particularly limited, but is, for example, 50 μm or more and 170 μm or less. For example, corona discharge treatment may be applied to the surface of the porous substrate facing the design layer in order to improve the adhesion of the ink forming the design layer.

[0104] The above-mentioned substrate and porous substrate contain a curable resin X. A wide range of thermosetting resins can be used as the curable resin X. Examples of thermosetting resins include melamine resins (melamine resin precursors), melamine-urea cocondensation resins, unsaturated polyester resins, polyurethane resins (including two-component curable polyurethanes), epoxy resins, aminoalkyd resins, phenolic resins, urea resins, diallyl phthalate resins, guanamine resins, silicon resins, and polysiloxane resins.

[0105] (iii) Design layer Design layers include, for example, solid color layers (layers with solid ink coverage) and pattern layers (layers with printed ink). Patterns (designs) in the pattern layer include, for example, wood grain patterns, stone patterns, sand patterns, tile patterns, brick patterns, fabric patterns, leather patterns, geometric figures, letters, symbols, abstract patterns, and floral patterns.

[0106] The design layer typically contains a coloring agent and a binder resin. Examples of coloring agents include inorganic pigments such as carbon black (ink), iron black, titanium white, antimony white, lead yellow, titanium yellow, reddish-brown, cadmium red, ultramarine, and cobalt blue; organic pigments (including dyes) such as quinacridone red, isoindolinone yellow, nickel azo complex, phthalocyanine blue, and azomethine azoblack; metallic pigments such as aluminum and brass; and pearl pigments such as titanium dioxide-coated mica and basic lead carbonate.

[0107] Examples of binder resins include urethane resins, acrylic polyol resins, acrylic resins, ester resins, amide resins, butyral resins, styrene resins, urethane-acrylic copolymers, vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-acrylic copolymers, chlorinated propylene resins, nitrocellulose resins, and cellulose acetate resins.

[0108] The design layer may contain additives such as ultraviolet absorbers, light stabilizers, curing agents, plasticizers, and catalysts, as needed. The thickness of the design layer may be, for example, 0.5 μm or more and 20 μm or less, 1 μm or more and 10 μm or less, or 2 μm or more and 5 μm or less.

[0109] One method for forming the design layer is to apply an ink containing a colorant, a binder resin, and a solvent, and then dry it. Gravure printing is preferred as the coating method.

[0110] (2) Heating and pressurizing process In this process, as shown in Figures 7(a) and 7(b), the decorative panel precursor 6A' and the surface S1 of the release sheet 10 on the barrier layer 2 side are placed facing each other, and heating and pressurizing are performed to obtain a cured laminate 50 in which the decorative panel 6A and the release sheet 10 are laminated together. In this process, for example, the curable resin X contained in the substrate 61 adheres to the barrier layer of the release sheet by hot pressing. Alternatively, in this process, heating and pressurizing may be performed with the first adhesive layer placed between the decorative panel precursor and the release sheet.

[0111] In the cured laminate 50 shown in Figure 7(b), the decorative panel 6A is in the thickness direction D T In this configuration, the base 61, porous substrate 62, and design layer 63 are arranged in this order, and the base 61 and porous substrate 62 contain cured products of curable resin X. In the cured laminate, the decorative panel and the release sheet may be laminated via a first adhesive layer.

[0112] Figure 8 is a schematic cross-sectional view illustrating a cured laminate in this disclosure. The cured laminate 50 shown in Figure 8 has a thickness direction D T In this configuration, the release sheet 10, the substrate 61, the porous substrate 62, the design layer 63, and the cured resin layer 64 are arranged in this order. The cured resin layer is formed, for example, from the same curable resin as the cured product of the curable resin X filled into the substrate and porous substrate described above.

[0113] The thickness of the cured resin layer is not particularly limited, but may be, for example, 1 μm or more, or 10 μm or more. On the other hand, the thickness of the cured resin layer may be, for example, 500 μm or less, or 300 μm or less.

[0114] The first adhesive layer may be transparent or opaque.

[0115] Examples of adhesives used in the first adhesive layer include curing adhesives and pressure-sensitive adhesives. Adhesives used in the dry lamination method are preferred, with thermosetting resins being a typical example. Dry lamination is a bonding method in which a liquid adhesive dissolved in a solvent is applied to at least one of the bonding surfaces of two members to be bonded together, and after drying, the two members, laminated with the adhesive layer in between, are sandwiched between a pair of room temperature or heated rolls and bonded together under pressure.

[0116] Specific examples include urethane-based adhesives, acrylic-based adhesives, epoxy-based adhesives, and rubber-based adhesives. Additionally, OCA (Optically Clear Adhesive) or OCR (Optically Clear Resin) can be used as the adhesive layer.

[0117] From the viewpoint of efficiently obtaining the desired adhesive strength, the thickness of the first adhesive layer is, for example, 5 μm to 100 μm, may be 10 μm to 75 μm, or 20 μm to 50 μm.

[0118] Methods for forming the first adhesive layer include, for example, applying an adhesive composition to a release sheet or decorative panel precursor, or laminating an adhesive film.

[0119] Examples of resins used to form the first adhesive layer include (meth)acrylic resin, (meth)acrylic-modified polyolefin, chlorinated polyolefin, vinyl chloride resin, vinyl acetate resin, vinyl chloride-vinyl acetate copolymer, styrene-(meth)acrylic copolymer, polyester, polyurethane, and polyamide. Two-component curing type polyurethane or polyester adhesives using isocyanate compounds or the like as curing agents can also be used. Examples of adhesives include (meth)acrylic, urethane, silicone, or rubber-based adhesives (pressure-sensitive adhesives).

[0120] (3) Bonding process In this process, as shown in Figure 7(c), the decorative material 100A is obtained by bonding the side of the cured laminate 50 facing the release sheet 10 to the adherend 3. The laminate and adherend may be laminated with a second adhesive layer in between.

[0121] Examples of adherends include wood-based materials, resin-based materials, metal-based materials, and ceramic-based materials.

[0122] The adherend may be a wood-based material. Examples of wood-based materials include wood fiberboard. Examples of wood fiberboard include wood veneer, wood plywood, laminated wood, particleboard, and MDF (medium-density fiberboard). Examples of wood materials for wood-based materials include cedar, cypress, pine, and lauan.

[0123] The adherend may be a metal component. Examples of metals used for the metal component include iron, aluminum, copper, and alloys containing one or more of these metals.

[0124] The adherend may be a resin component. Examples of resins used for resin components include acrylic resin, polyester resin, polystyrene resin, polyolefin resin such as polypropylene, ABS (acrylonitrile-butadiene-styrene copolymer) resin, phenolic resin, vinyl chloride resin, cellulose resin, and rubber.

[0125] The adherend may be a ceramic component. The material of the ceramic component may be ceramics such as glass or porcelain, non-cement ceramic materials such as gypsum, or non-ceramic ceramic materials such as ALC (autoclaved lightweight concrete).

[0126] Examples of resins used to form the second adhesive layer include those similar to those exemplified for the first adhesive layer.

[0127] II. Second Embodiment Figure 9 is a schematic cross-sectional view illustrating the method for manufacturing a decorative material in this embodiment. As shown in Figure 9, the method for manufacturing a decorative material in this disclosure includes a preparation step (Figure 9(a)) of preparing the above-mentioned release sheet 10 and decorative sheet 6B, a dry lamination step (Figure 9(b)) of placing the decorative sheet 6B and the surface S1 on the barrier layer 2 side of the release sheet 10 facing each other and bonding them via an adhesive layer 4 to obtain a laminate 55, and a bonding step (Figure 9(c)) of bonding the surface of the laminate 55 on the release sheet 10 side to the adherend 3 to obtain the decorative material 100B.

[0128] With the method for manufacturing decorative materials described in this disclosure, a decorative material is obtained in which the release sheet described above is arranged between the decorative sheet and the adherend in the thickness direction. For the reasons described above, such a decorative material allows for easy separation of the adherend and the decorative sheet by delamination at the base layer of the release sheet, and the decorative material exhibits good adhesion between the decorative sheet and the release sheet during use.

[0129] (1) Preparation process (a) Release sheet The release sheet to be prepared in this process is the same as described in "A. Release Sheet" above, so its explanation is omitted here.

[0130] (b) decorative sheet As shown in Figure 9(a), the decorative sheet prepared in this process has, for example, a thickness direction D T In this configuration, the decorative sheet has a base layer 64 and a design layer 65. The decorative sheet may have other layers besides the base layer and the design layer. Examples of other layers include a transparent resin layer and a surface protection layer. As shown in Figure 10, the decorative sheet 6B has a thickness direction D T In this configuration, the base layer 64, the design layer 65, and the surface protection layer 66 may be arranged in this order.

[0131] (i) Base material layer A decorative sheet, for example, has a base layer. The presence of a base layer in a decorative sheet improves various properties such as mechanical strength, suitability for post-processing, and design aesthetics, thereby enhancing its usability as a sheet.

[0132] The base material layer is not particularly limited, and examples include resin base materials. The type of base material layer is appropriately selected depending on the application of the decorative sheet.

[0133] Examples of resins used in resin substrates include various synthetic resins and various natural resins. Examples of synthetic resins include thermoplastic resins and curable resins. Considering the suitability for manufacturing, handling, and post-processing of decorative sheets, thermoplastic resins are preferred.

[0134] Examples of thermoplastic resins include olefin resins such as polyethylene, polypropylene, polymethylpentene, ionomers, and various olefin-based thermoplastic elastomers; vinyl chloride resins such as polyvinyl chloride, polyvinylidene chloride, and vinyl chloride-vinyl acetate copolymers; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, ethylene glycol-terephthalic acid-isophthalic acid copolymers, and polyester-based thermoplastic elastomers; acrylic resins such as poly(meth)acrylate, poly(meth)acrylate, poly(meth)acrylate, poly(meth)acrylate-(meth)acrylate copolymers; polyamide resins represented by nylon 6 and nylon 66; cellulose resins such as cellulose triacetate, cellophane, and celluloid; styrene resins such as polystyrene, acrylonitrile-styrene copolymer, and acrylonitrile-butadiene-styrene copolymer (ABS resin); polyvinyl alcohol, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polycarbonate resin, polyarylate resin, and polyimide resin.

[0135] Examples of natural resins include natural rubber, pine resin, and amber.

[0136] Examples of curable resins include ionizing radiation-curable resins and thermosetting resins.

[0137] The substrate layer may contain additives as needed. In the case of a resin substrate, examples of additives include inorganic fillers, flame retardants, lubricants, foaming agents, antioxidants, UV absorbers, light stabilizers, and colorants. Various additives can be used individually or in combination. There are no particular restrictions on the amount of additives, as long as they do not impair the surface properties or processing properties, and they can be set appropriately according to the required properties.

[0138] The base layer may be a single layer or a laminate of two or more layers. In the case of a laminate, the base layer may consist of two or more layers of the same type of base material or two or more layers of different types of base materials.

[0139] In this disclosure, the substrate layer may also serve as the design layer described later.

[0140] The base layer may be transparent or opaque. If the base layer is opaque, it can serve as the design layer.

[0141] Furthermore, the base layer may be colored. If the base layer is colored, the base layer can become the design layer. The manner of coloring is not particularly limited; it may be transparent coloring or opaque coloring (concealing coloring), and these can be chosen arbitrarily.

[0142] If the base layer is colored, it may contain a coloring agent. Examples of coloring agents include white pigments such as titanium white, inorganic pigments such as iron black, lead yellow, titanium yellow, reddish-brown, cadmium red, ultramarine, and cobalt blue; organic pigments or dyes such as quinacridone red, isoindolinone yellow, phthalocyanine blue, nickel-azo complexes, azomethine azo black pigments, and perylene black pigments; metallic pigments consisting of flaky foil pieces such as aluminum and brass; and pearlescent pigments consisting of flaky foil pieces such as titanium dioxide-coated mica and basic lead carbonate. For example, if the surface hue of the substrate on which the decorative sheet is laminated varies, and it is desired to conceal the surface hue and improve the stability of the color tone of the decorative layer, an inorganic pigment such as a white pigment may be used.

[0143] The substrate layer may be surface-treated to improve adhesion to the layer in contact with it, such as adhesion to the design layer or adhesive layer. Examples of surface treatments include physical surface treatments such as oxidation and embossing, and chemical surface treatments. Examples of oxidation methods include corona discharge treatment, chromium oxidation treatment, flame treatment, hot air treatment, and ozone-ultraviolet treatment. Examples of embossing methods include sandblasting and solvent treatment. These surface treatments are appropriately selected depending on the type of substrate layer, but corona discharge treatment is generally preferred considering the effectiveness and ease of operation of the surface treatment.

[0144] Furthermore, if the base layer is a laminate, an adhesive layer or primer layer may be placed between each layer to improve the adhesion between adjacent layers.

[0145] The thickness of the base layer is not particularly limited and is appropriately selected depending on the material of the base layer. In the case of a base layer containing resin, the thickness of the base layer may be, for example, 10 μm or more and 300 μm or less, 20 μm or more and 200 μm or less, or 40 μm or more and 100 μm or less.

[0146] (ii) Design layer The decorative sheet in this disclosure may have a design layer on one side of the base layer. Furthermore, if the decorative sheet has a transparent resin layer as described later, the design layer may be located between the base layer and the transparent resin layer. Providing a design layer improves the aesthetic appeal of the decorative sheet. Also, when the decorative sheet is viewed in plan along its thickness, the design layer may be located across the entire surface of the decorative sheet or on a portion of it.

[0147] The design layer is the same as that of the decorative panel described above, so a detailed explanation is omitted here.

[0148] (iii) Surface protective layer The decorative sheet in this disclosure may have a surface protection layer on the side of the design layer opposite to the base material layer. The decorative sheet may have the surface protection layer as the outermost layer. Having a surface protection layer can provide durability (e.g., scratch resistance, stain resistance, weather resistance). On the other hand, the decorative sheet may not have a surface protection layer.

[0149] The surface protective layer contains a resin component. The resin component mainly functions as a binder resin. Preferably, the surface protective layer contains at least one of a resin composition and its cured product as the resin component. The cured product may be a cured product obtained by curing a curable resin composition with ionizing radiation, or a cured product obtained by curing a curable resin composition with heat.

[0150] Examples of curable resin compositions include ionizing radiation-curable resin compositions and thermosetting resin compositions. From the viewpoint of scratch resistance and production efficiency, ionizing radiation-curable resin compositions are preferred. That is, the surface protective layer preferably contains a cured product of the ionizing radiation-curable resin composition as a resin component.

[0151] Specific examples of ionizing radiation-curable resin compositions include electron beam-curable resin compositions and ultraviolet-curable resin compositions. Among these, electron beam-curable resin compositions have advantages such as less odor due to the elimination of polymerization initiators and less discoloration.

[0152] Ionizing radiation-curable resin compositions are compositions containing compounds having ionizing radiation-curable functional groups (hereinafter also referred to as "ionizing radiation-curable compounds"). Ionizing radiation-curable functional groups are groups that crosslink and harden upon irradiation with ionizing radiation. Specific examples include functional groups having ethylenic double bonds, such as (meth)acryloyl groups, vinyl groups, and allyl groups. Other specific examples of ionizing radiation-curable functional groups include epoxy groups and oxetanyl groups. In this specification, (meth)acryloyl group refers to acryloyl group or methacloyl group. In this specification, (meth)acrylate refers to acrylate or methacrylate. Ionizing radiation refers to electromagnetic waves or charged particle beams that have energy quanta capable of polymerizing or crosslinking molecules. Specific examples of ionizing radiation include ultraviolet rays (UV) and electron beams (EB). Other specific examples of ionizing radiation include electromagnetic waves such as X-rays and gamma rays, and charged particle beams such as alpha rays and ion beams.

[0153] The ionizing radiation-curable resin composition may contain only one ionizing radiation-curable compound, or it may contain two or more. The type of ionizing radiation-curable compound is not particularly limited, and known polymerizable monomers and known polymerizable oligomers (polymerizable prepolymers) can be used.

[0154] Ionizing radiation-curable compounds preferably contain compounds having two or more ethylenically unsaturated bonding groups. In particular, ionizing radiation-curable compounds preferably contain polyfunctional (meth)acrylate compounds having two or more ethylenically unsaturated bonding groups. The polyfunctional (meth)acrylate compounds may be monomers or oligomers.

[0155] The polyfunctional (meth)acrylate compounds may be difunctional (meth)acrylate monomers or trifunctional (meth)acrylate monomers. Examples of difunctional (meth)acrylate monomers include ethylene glycol di(meth)acrylate, bisphenol A tetraethoxydiacrylate, bisphenol A tetrapropoxydiacrylate, and 1,6-hexanediol diacrylate. Examples of trifunctional (meth)acrylate monomers include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and isocyanuric acid-modified tri(meth)acrylate.

[0156] Examples of polyfunctional (meth)acrylate oligomers include acrylate polymers such as urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, and polyether (meth)acrylate.

[0157] Urethane (meth)acrylates can be obtained, for example, by the reaction of polyhydric alcohols and organic diisocyanates with hydroxy(meth)acrylate. Epoxy (meth)acrylates can also be obtained, for example, by the reaction of epoxy resins with (meth)acrylic acid. At least one of polybasic acids and phenols may be further used in this reaction. Epoxy resins may be bifunctional, trifunctional, or more functional. Examples of epoxy resins include aromatic epoxy resins, alicyclic epoxy resins, and aliphatic epoxy resins.

[0158] The ionizing radiation-curable compound may contain silicone (meth)acrylate. Using silicone (meth)acrylate improves the stain resistance of the surface protective layer. Examples of silicone (meth)acrylate include silicone oil containing polysiloxane. The silicone (meth)acrylate may also be a modified silicone oil in which (meth)acrylic groups are introduced at the ends of the polysiloxane. The content of silicone (meth)acrylate may be, for example, 1 part by mass or more and 7 parts by mass or less, and 2 parts by mass or more and 5 parts by mass or less, per 100 parts by mass of the ionizing radiation-curable compound (excluding silicone (meth)acrylate).

[0159] When the ionizing radiation-curable compound is an ultraviolet-curable compound, the ionizing radiation-curable resin composition preferably contains additives such as photopolymerization initiators and photopolymerization accelerators. Examples of photopolymerization initiators include acetophenone, benzophenone, α-hydroxyalkylphenone, Michler ketone, benzoin, benzyldimethyl ketal, benzoylbenzoate, α-acyloxime ester, and thioxanthone. Examples of photopolymerization accelerators include isoamyl p-dimethylaminobenzoate and ethyl p-dimethylaminobenzoate.

[0160] On the other hand, a thermosetting resin composition is a composition containing at least a thermosetting resin. This resin composition hardens upon heating. Examples of thermosetting resins include acrylic resins, urethane resins, phenolic resins, urea-melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins. The thermosetting resin composition may optionally contain additives such as curing agents and curing catalysts.

[0161] The surface protective layer may further contain at least one of the following as additives: antioxidants, light stabilizers, ultraviolet absorbers, antibacterial agents, antiviral agents, and anti-allergen agents. Examples of antioxidants include phenolic antioxidants, sulfuric antioxidants, and phosphorusic antioxidants. Among these, phosphorusic antioxidants can effectively suppress discoloration of the surface protective layer due to light. Examples of light stabilizers include hindered amine compounds. Hindered amine compounds usually have a structure that includes a 2,2,6,6-tetramethylpiperidine skeleton in their molecule. Examples of hindered amine compounds include NH-type hindered amine compounds, NR-type hindered amine compounds, and NOR-type hindered amine compounds. Examples of ultraviolet absorbers include benzotriazole-type ultraviolet absorbers, benzophenone-type ultraviolet absorbers, and triazine-type ultraviolet absorbers.

[0162] The thickness of the surface protection layer is not particularly limited, but for example, it is between 1 μm and 50 μm. If the surface protection layer is too thin, it may not provide sufficient durability, and if the surface protection layer is too thick, the visibility of the design layer may be reduced. The thickness of the surface protection layer may be between 3 μm and 40 μm, or between 5 μm and 35 μm.

[0163] One method for forming a surface protective layer is to apply a mixture containing a resin component and additives to the surface of a resin layer, dry it, and cure it. Alternatively, the above mixture may be applied to the surface of a release-type substrate, dried, and cured to form a surface protective layer, and then this surface protective layer may be transferred onto the resin layer.

[0164] The decorative sheet may have an embossed pattern on the outermost surface on the side of the protective surface layer, relative to the base material layer. In particular, it is preferable that the embossed pattern is located on the side of the protective surface layer opposite to the base material layer. Examples of embossed patterns include wood grain grooves, stone surface irregularities, fabric surface textures, pearlescent finishes, sand textures, hairline finishes, and fine-line grooves.

[0165] One method for forming an embossed pattern is to heat a decorative sheet and press an embossing plate onto it. The heating temperature of the decorative sheet may be, for example, 80°C or higher and 260°C or lower, but may also be 85°C or higher and 200°C or lower, or 100°C or higher and 180°C or lower.

[0166] (2) Dry lamination process In this process, as shown in Figures 9(a) and 9(b), the decorative sheet 6B and the surface S1 of the release sheet 10 on the barrier layer 2 side are placed opposite each other and bonded together via an adhesive layer (first adhesive layer) 4 to obtain a laminate 55.

[0167] The first adhesive layer is the same as the first adhesive layer in the decorative panel described above, so its explanation is omitted here.

[0168] (3) Bonding process In this process, as shown in Figure 9(c), the decorative material 100B is obtained by bonding the side of the laminate 55 facing the release sheet 10 to the adherend 3. The laminate and adherend may be laminated with a second adhesive layer in between.

[0169] The second adhesive layer is the same as the second adhesive layer in the decorative panel described above, so its explanation is omitted here. The adherend is the same as the adherend in the manufacturing method of the decorative panel (first embodiment) described above, so its explanation is omitted here.

[0170] This disclosure is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of this disclosure and achieves similar effects is included within the technical scope of this disclosure. [Examples]

[0171] [Examples 1-3] A paper 1 was prepared containing kraft pulp, a paper strength enhancer, and a sizing agent as a base layer, having the following physical properties. A barrier layer was formed by applying the following barrier layer composition 1, heated to 40°C, to one side of the base layer using gravure direct to the coating amount and surface roughness shown in Table 1, and then curing it by electron beam irradiation (irradiation dose 165kV, 5Mrad). This yielded a release sheet.

[0172] (Physical properties of paper 1) ·Basic weight: 60g / m 2 Thickness: 95 μm • Paper-to-paper peel strength (paper-to-paper peel strength before barrier layer formation): 600mN / 15mm • Pure water contact angle of the surface forming the barrier layer: 110° • Surface Rz of the barrier layer: 12.3 μm • Surface Ra of the barrier layer: 1.4 μm

[0173] (Composition for barrier layer 1) • Ionizing radiation-hardening compound (acrylate monomer): 100 parts by mass • Silica: 18 parts by mass

[0174] [Example 4] As a base layer, paper 1 was prepared. On one side of the base layer, the barrier layer composition 2 shown below, heated to 40°C, was applied by gravure direct to the coating amount and surface roughness shown in Table 1, and cured by electron beam irradiation (irradiation dose 165kV, 5Mrad) to form a barrier layer. This obtained a release sheet.

[0175] (Barrier layer composition 2) • Ionizing radiation-hardening compound (acrylate monomer): 100 parts by mass • Silica: 25 parts by mass

[0176] [Example 5] Paper 2 was prepared as a base layer, containing kraft pulp, a paper strength enhancer, a sizing agent, and titanium dioxide pigment, and having the following physical properties. The titanium dioxide pigment was blended to be 33% by mass relative to the total mass of the kraft pulp, paper strength enhancer, and sizing agent. The barrier layer composition 1, heated to 40°C, was applied to one side of the base layer by gravure direct to the coating amount and surface roughness shown in Table 1, and cured by electron beam irradiation (irradiation dose 165kV, 5Mrad) to form a barrier layer. This obtained a release sheet.

[0177] (Physical properties of paper 2) ·Basic weight: 80g / m 2 Thickness: 100 μm • Paper-to-paper peel strength (paper-to-paper peel strength before barrier layer formation): 600mN / 15mm • Pure water contact angle of the surface forming the barrier layer: 20° • Surface Rz of the barrier layer: 16.7 μm • Surface Ra of the barrier layer: 2.5 μm

[0178] [Example 6] As a base layer, paper 1 was prepared. On one side of the base layer, the barrier layer composition 3 described below was applied by gravure direct to the coating amount and surface roughness shown in Table 1. After application, the coating layer was cured by heat drying in an oven at 70°C for 24 hours to obtain a barrier layer. This resulted in a release sheet.

[0179] (Barrier layer composition 3) The following main ink, curing agent, and diluent were blended in a ratio of 100:5:40 (by mass) to obtain barrier layer composition 3. <Main Ink> • Resin: Acrylic polyol: 20% by mass • Additive: Silica: 10% by mass • Solvent: Methyl ethyl ketone: 5% by mass Ethyl acetate: 45% by mass Butyl acetate: 20% by mass <Hardening agent> Polyisocyanate (HDI) / Ethyl acetate = 75% by mass / 25% by mass <Diluting solvent> ethyl acetate

[0180] [Example 7] As a base layer, paper 1 was prepared. On one side of the base layer, the barrier layer composition 4 described below was applied by gravure direct to the coating amount and surface roughness shown in Table 1. After application, the coating layer was cured by heat drying in an oven at 70°C for 24 hours to obtain a barrier layer. This resulted in a release sheet.

[0181] (Composition for barrier layer 4) The following main ink, curing agent, diluent, and silicone oil were blended in a ratio of 100:5:40:18 (by mass) to obtain barrier layer composition 4. <Main Ink> • Resin: Acrylic polyol: 20% by mass • Additive: Silica: 10% by mass • Solvent: Methyl ethyl ketone: 5% by mass Ethyl acetate: 45% by mass Butyl acetate: 20% by mass <Hardening agent> Polyisocyanate (HDI) / Ethyl acetate = 75% by mass / 25% by mass <Diluting solvent> ethyl acetate <Silicone oil> Silicone oil / ethyl acetate = 18% by mass / 82% by mass

[0182] [Example 8] As a base layer, paper 1 was prepared. On one side of the base layer, the barrier layer composition 5 described below was applied by gravure direct to the coating amount and surface roughness shown in Table 1. After application, the coating layer was cured by heat drying in an oven at 70°C for 24 hours to obtain a barrier layer. This resulted in obtaining a release sheet.

[0183] (Barrier layer composition 5) The following main ink, curing agent, and diluent were blended in a ratio of 100:4:30 (by mass) to obtain barrier layer composition 5. <Main Ink> • Resin (acrylic resin): 8% by mass • Additives (titanium dioxide pigment): 55% by mass • Plasticizer (diisononyl adipate): 2% by mass • Solvent: Ethyl acetate : 35% by mass <Hardening agent> Polyisocyanate (HDI) / Ethyl acetate = 75% by mass / 25% by mass <Diluting solvent> ethyl acetate

[0184] [Example 9] As a base layer, paper 1 was prepared. The barrier layer composition 1 was applied to one side of the base layer by gravure direct in the amount shown in Table 1, and cured by electron beam irradiation (irradiation dose 165kV, 5Mrad) to form a barrier layer. This obtained a release sheet.

[0185] [Comparative Example 1] As a base layer, paper 1 was prepared. On one side of the base layer, the barrier layer composition 6 shown below, heated to 40°C, was applied by gravure direct to the coating amount and surface roughness shown in Table 1, and cured by electron beam irradiation (irradiation dose 165kV, 5Mrad) to form a barrier layer. This obtained a release sheet.

[0186] (Barrier layer composition 6) <Main Ink> • Ionizing radiation-hardening compound (acrylate monomer): 100 parts by mass • Additive (silica): 38 parts by mass

[0187] [Comparative Example 2] As a base layer, paper 2 was prepared. On one side of the base layer, the barrier layer composition 1, heated to 40°C, was applied by gravure direct to the coating amount and surface roughness shown in Table 1, and cured by electron beam irradiation (irradiation dose 165kV, 5Mrad) to form a barrier layer. This obtained a release sheet.

[0188] [Comparative Example 3] As a base layer, paper 1 was prepared. On one side of the base layer, the barrier layer composition 7 shown below was applied by gravure direct to the coating amount and surface roughness shown in Table 1, and a barrier layer was formed by curing with electron beam irradiation (irradiation dose 165kV, 5Mrad). This obtained a release sheet.

[0189] (Barrier layer composition 7) The following main ink and diluent were mixed in a ratio of main ink / diluent = 100 / 10 (by mass) to prepare barrier layer composition 7. <Main Ink> ·Ionizing radiation-curable compounds Acrylates oligomer: 40% by mass Acrylates monomer: 17% by mass • Additives Silica: 9% by mass Reactive silicone (manufactured by Shin-Etsu Chemical Co., Ltd., X-22-164B): 4% by mass ·solvent Methyl ethyl ketone / isopropyl alcohol = 18% by mass: 12% by mass <Diluting solvent> Methyl ethyl ketone

[0190] [Comparative Example 4] As a base layer, paper 1 was prepared. On one side of the base layer, the barrier layer composition 1, heated to 40°C, was applied by gravure direct to the coating amount and surface roughness shown in Table 1, and cured by electron beam irradiation (irradiation dose 165kV, 5Mrad) to form a barrier layer. This obtained a release sheet.

[0191] (Manufacturing of decorative materials 1) A decorative sheet was prepared by forming a design layer and a surface protection layer in that order on a base layer containing polypropylene resin and a coloring pigment using a gravure printing method. Next, the barrier layer side surface of the release sheet obtained in Examples 1 to 8 and Comparative Examples 1 to 4 was bonded to the base layer side surface of the decorative sheet via a first adhesive layer using a dry lamination method to obtain a laminate in which the release sheet and the decorative sheet were laminated. The release sheet side surface (underlayment layer surface) of the laminate and the adherend were bonded via a second adhesive layer. This resulted in a decorative material having the decorative sheet, first adhesive layer, release sheet, second adhesive layer, and adherend in that order.

[0192] (Manufacturing of decorative materials 2) In Example 9, a decorative laminate containing phenol resin-impregnated paper and melamine resin-impregnated paper was laminated onto the barrier layer side surface of the release sheet obtained in Example 9, and a heat press was performed to form a cured laminate in which the release sheet and decorative laminate were laminated. The release sheet side surface (underlying layer surface) of the cured laminate and the adherend were bonded together via a second adhesive layer. This resulted in a decorative material having the decorative laminate, release sheet, second adhesive layer, and adherend in this order.

[0193] (Reference Examples 1 and 2) A decorative sheet was prepared by forming a design layer and a surface protection layer in that order on a substrate containing polypropylene resin and coloring pigment using a gravure printing method. Paper 1 and paper 2 were used as release sheets. One side of the release sheet was bonded to the substrate layer side of the decorative sheet via a first adhesive layer using a dry lamination method, forming a laminate in which the release sheet and the decorative sheet were laminated. The release sheet side of the laminate (the base layer side) and the adherend were bonded via a second adhesive layer. This resulted in a decorative material having the decorative sheet, first adhesive layer, release sheet (paper), second adhesive layer, and adherend in that order.

[0194] [Measurement of contact angle with pure water] The pure water contact angle was measured on the barrier layer side surface of the release sheets obtained in Examples 1 to 9 and Comparative Examples 1 to 4 using the method described above.

[0195] [Surface roughness measurement] For the barrier layer side surface of the release sheets obtained in Examples 1 to 9 and Comparative Examples 1 to 4, Rz (maximum height) and Ra (arithmetic mean roughness) were measured using the method described above.

[0196] [Evaluation of decorative materials] The edges of the obtained decorative material were rubbed with a finger, and the adhesion between the decorative body, which consists of a decorative sheet or decorative board, and the release sheet was evaluated according to the following evaluation criteria. A: There are no lifting or other defects on the surface, and the decorative material and the release sheet do not separate even when the edges are rubbed with a finger. B: Some lifting or other imperfections are visible on the exterior, but the decorative material and the release liner do not separate even when the edges are rubbed with a finger. C: If you rub the edges with your finger, the decorative material and the release sheet will separate.

[0197] [Evaluation of peelability] A metal spatula was pressed against the side of the decorative material obtained in the examples and comparative examples to create a point for separation between the adherend and the release sheet. The decorative material was then peeled off by hand from this point, and the ease of separation from the adherend was evaluated according to the following evaluation criteria. A: The paper can be peeled apart, allowing for easy separation of the decorative material and the substrate. B: There are some areas where the paper does not peel off properly, but generally the decorative material and the substrate can be separated. C: The decorative material does not peel off from the paper, and the decorative material is damaged, making it difficult to separate the decorative material from the substrate.

[0198] [Table 1]

[0199] [Table 2]

[0200] As shown in Table 1, decorative materials using release sheets having a base layer and a barrier layer, with the pure water contact angle and Rz (maximum height) of the barrier layer side surface being within predetermined ranges, exhibited high adhesion between the decorative element and the release sheet during use, and allowed for easy separation of the decorative element from the adherend after use (Examples 1-9). On the other hand, as shown in Table 2, when the Rz of the barrier layer side surface of the release sheet was too large, as in Comparative Examples 1 and 2, excessive penetration of the adhesive resin into the base layer occurred, making it impossible to peel the material from the base layer. When the pure water contact angle of the barrier layer side surface of the release sheet was high, as in Comparative Example 3, it was confirmed that the adhesive did not adhere to the release sheet during the preparation of the decorative material. When the Rz was too small, as in Comparative Example 4, it was confirmed that the adhesive did not adhere to the release sheet during the preparation of the decorative material. Therefore, peelability evaluation could not be performed for Comparative Examples 3 and 4 (NA in Table 2). As shown in Reference Examples 1 and 2, it was confirmed that release sheets without a barrier layer do not suppress the penetration of adhesive resin into the substrate layer, making delamination between the sheets difficult.

[0201] Thus, the present disclosure provides, for example, the following inventions.

[0202] [1] A release sheet used in a decorative material having a decorative body which is a decorative sheet or decorative panel and an adherend, The above release sheet has a paper base layer and a barrier layer containing resin, which is placed on one side of the base layer. The above-mentioned release sheet is a sheet that is placed between the decorative body and the adherend in the thickness direction. The surface of the release sheet on the barrier layer side has a pure water contact angle of 120° or less, and the Rz (maximum height) as defined in JIS B0601:2013 is 4.0 μm or more and 10.0 μm or less.

[0203] [2] The release sheet described in [1], wherein the surface of the release sheet on the barrier layer side has an arithmetic mean roughness (Ra) of 0.5 μm or more and 1.2 μm or less, as defined in JIS B0601:2013.

[0204] [3] The above paper is a release sheet as described in [1] or [2], containing plant fibers.

[0205] [4] The basis weight of the above paper is 30 g / m². 2 More than 100g / m 2 The release sheet described in any of the following [1] to [3].

[0206] [5] The barrier layer is a release sheet according to any one of [1] to [4], wherein the resin is a cured product of a thermosetting resin or a cured product of an electron beam curable resin.

[0207] [6] The barrier layer is a release sheet according to any one of [1] to [5], wherein the resin is at least one of the following: acrylic polyol resin, vinyl chloride-vinyl acetate copolymer, acrylic acrylate resin, urethane acrylate resin, polycarbonate resin, polyethylene terephthalate resin, urethane resin, epoxy resin, or olefin resin.

[0208] [7] The above-mentioned release sheet has a paper-to-paper peel strength of 100 mN / 15 mm or more and 1000 mN / 15 mm or less, as described in any of [1] to [6].

[0209] [8] A method for manufacturing a decorative material having a decorative panel and an adherend, The above-mentioned release sheet and a decorative panel precursor containing a curable resin are prepared in a preparation step, A heating and pressurizing step is performed by placing the decorative panel precursor and the surface of the release sheet on the barrier layer side facing each other, and heating and pressurizing to cure the curable resin and obtain a cured laminate. A method for manufacturing a decorative material, comprising a bonding step of bonding the surface of the cured laminate on the release sheet side to the adherend to obtain the decorative material.

[0210] [9] A method for manufacturing a decorative material having a decorative sheet and an adherend, Preparation steps for preparing the aforementioned release sheet and the decorative sheet, A dry lamination process is performed by placing the decorative sheet and the surface of the release sheet on the barrier layer side facing each other and bonding them together via an adhesive layer to obtain a laminate. A method for manufacturing a decorative material, comprising a bonding step of bonding the surface of the laminate on the release sheet side to the adherend to obtain the decorative material. [Explanation of Symbols]

[0211] 1 … Base layer 2… Barrier layer 3 … Adherent 4… First adhesive layer 5. Second adhesive layer 6… Decorative material 6A… Decorative panel 6B… Decorative sheet 10… Release sheet 100, 100A, 100B… Decorative materials

Claims

1. A release sheet used in a decorative material having a decorative body which is a decorative sheet or decorative panel and an adherend, The release sheet has a base layer which is paper, and a barrier layer which is disposed on at least one surface of the base layer and contains resin. The release sheet is a sheet that is placed between the decorative body and the adherend in the thickness direction. The surface of the release sheet on the barrier layer side has a pure water contact angle of 120° or less, and the Rz (maximum height) as defined in JIS B0601:2013 is 4.0 μm or more and 10.0 μm or less.

2. The release sheet according to claim 1, wherein the surface of the release sheet on the barrier layer side has an arithmetic mean roughness (Ra) of 0.5 μm or more and 1.2 μm or less, as defined in JIS B0601:2013.

3. The aforementioned paper is a release sheet according to claim 1, wherein the paper contains plant fibers.

4. The basis weight of the aforementioned paper is 30 g / m². ２ Above, 100g / m ２ The release sheet according to claim 1, which is as follows:

5. The release sheet according to claim 1, wherein the barrier layer includes a cured product of a thermosetting resin or a cured product of an electron beam curable resin as the resin.

6. The release sheet according to claim 1, wherein the barrier layer contains at least one of the following resins: acrylic polyol resin, vinyl chloride-vinyl acetate copolymer, acrylic acrylate resin, urethane acrylate resin, polycarbonate resin, polyethylene terephthalate resin, urethane resin, epoxy resin, and olefin resin.

7. The release sheet according to claim 1, wherein the inter-paper peel strength of the release sheet is 100 mN / 15 mm or more and 1000 mN / 15 mm or less.

8. A method for manufacturing a decorative material having a decorative panel and an adherend, A preparation step of preparing a release sheet according to any one of claims 1 to 7 and a decorative panel precursor containing a curable resin, A heating and pressurizing step is performed by placing the decorative panel precursor and the surface of the release sheet on the barrier layer side facing each other, and heating and pressurizing to cure the curable resin and obtain a cured laminate. A method for manufacturing a decorative material, comprising a bonding step of bonding the surface of the cured laminate on the release sheet side to the adherend to obtain the decorative material.

9. A method for manufacturing a decorative material having a decorative sheet and an adherend, A preparation step of preparing the release sheet according to any one of claims 1 to 7 and the decorative sheet, A dry lamination process is performed by placing the decorative sheet and the surface of the release sheet on the barrier layer side facing each other and bonding them together via an adhesive layer to obtain a laminate. A method for manufacturing a decorative material, comprising a bonding step of bonding the surface of the laminate on the release sheet side to the adherend to obtain the decorative material.

Images