Resin-impregnated decorative panel comprising release film, release film, and method for producing resin-impregnated decorative panel

Abstract

The present disclosure provides a resin-impregnated decorative panel comprising a release film, which has a core base material, a decorative sheet, a cured resin layer, and a release film in this order in the thickness direction, wherein: the decorative sheet has a porous base material, a design layer, and a release layer having a pattern shape in this order from the core base material side in the thickness direction; the decorative sheet and the cured resin layer contain a cured product of a curable resin Y; the release film has a thickness of 30 µm or more; the pure water contact angle on the cured resin layer-side surface of the release film is 70.0° to 95.0° inclusive; and the release film contains a polyolefin-based resin or a polyester-based resin.

Description

Resin-impregnated decorative board including release film, release film, and method for manufacturing a resin-impregnated decorative board.

[0001] This disclosure relates to a resin-impregnated decorative laminate including a release film, a release film, and a method for manufacturing a resin-impregnated decorative laminate.

[0002] Resin-impregnated decorative panels are known in which a melamine resin precursor is impregnated into a porous substrate and then cured. Resin-impregnated decorative panels are used, for example, on walls, floors, and furniture. On the other hand, resin-impregnated decorative panels that express a glossy-matt finish are also known. For example, Patent Document 1 discloses a decorative panel in which a release layer is present in a part of the surface of the porous substrate, and a thermosetting resin layer is present in the remaining area of ​​the surface of the porous substrate that does not have a release layer, and the thermosetting resin is impregnated into the porous substrate and cured.

[0003] Patent Document 2 discloses a release sheet, wherein the release sheet comprises a base sheet and a surface layer forming the first surface of the release sheet, and the surface layer is formed of a cured product of an ionizing radiation-curable resin composition containing an ionizing radiation-curable resin and a silane coupling agent having an amino group, and the amount of the silane coupling agent contained in the ionizing radiation-curable resin composition is 3 parts by mass or more and 9 parts by mass or less per 100 parts by mass of the ionizing radiation-curable resin.

[0004] Patent No. 6716877, Patent No. 7008277

[0005] Patent Document 2 describes a method for producing a resin-impregnated decorative panel containing a release film (release sheet) by heat and pressure processing, and then peeling the release film from the resin-impregnated decorative panel to produce a resin-impregnated decorative panel with a gloss-matt finish. Specifically, when peeling off the release film, in areas where a release layer is not formed, the release film is peeled off from the cured resin layer in the resin-impregnated decorative panel, and in areas where a release layer is formed, the release film is peeled off together with the cured resin layer in the resin-impregnated decorative panel. This makes it possible to express a gloss-matt finish due to the difference in gloss between the release layer and the cured resin layer.

[0006] Thus, the release film is required to selectively remove the cured resin layer on the release layer after heat and pressure processing. To selectively remove the cured resin layer on the release layer, controlling the adhesion between the release film and the cured resin layer is important. If the adhesion between the release film and the cured resin layer is too high, it becomes difficult to peel the release film from the cured resin layer. On the other hand, if the adhesion between the release film and the cured resin layer is too low, it becomes difficult to selectively remove the cured resin layer on the release layer.

[0007] This disclosure has been made in view of the above circumstances, and its main purpose is to provide a resin-impregnated decorative panel including a release film that achieves both the peelability of the release film and the ease of removing the cured resin layer on the release layer.

[0008] This disclosure provides a resin-impregnated decorative panel including a release film, having a core substrate, a decorative sheet, a cured resin layer, and a release film in this order in the thickness direction, wherein the decorative sheet has, in the thickness direction from the core substrate side, a porous substrate, a design layer, and a release layer having a pattern shape, the decorative sheet and the cured resin layer contain a cured product of a curable resin Y, the release film has a thickness of 30 μm or more, the pure water contact angle on the surface of the release film facing the cured resin layer is 70.0° or more and 95.0° or less, and the release film contains a polyolefin resin or a polyester resin.

[0009] This disclosure provides a release film used in the manufacture of a resin-impregnated decorative panel, having a core substrate, a decorative sheet, and a cured resin layer in this order in the thickness direction, wherein the decorative sheet has, in the thickness direction from the core substrate side, a porous substrate, a design layer, and a release layer having a pattern shape, the decorative sheet and the cured resin layer contain a cured product of a curable resin Y, the cured resin layer is arranged between the patterns of the release layer, the release film has a thickness of 30 μm or more, the pure water contact angle on the surface of the release film facing the cured resin layer is 70.0° or more and 95.0° or less, and the release film contains a polyolefin resin or a polyester resin.

[0010] This disclosure relates to a method for manufacturing a resin-impregnated decorative panel, comprising: a preparation step of preparing a decorative sheet having a porous substrate, a design layer, and a release layer having a pattern shape in this order in the thickness direction; a laminate formation step of forming a laminate having (i) a core substrate, the decorative sheet, a curable resin layer containing a curable resin Y, and a release film in this order in the thickness direction, (ii) the surface of the decorative sheet facing the porous substrate, and (iii) the decorative sheet being impregnated with the curable resin Y; and heating and pressurizing the laminate to cure the curable resin Y. The present invention provides a method for manufacturing a resin-impregnated decorative laminate, comprising: a heating and pressing step to form a cured resin layer from a curable resin layer and obtain a cured laminate; and a peeling step to peel the release film from the cured laminate, thereby removing the cured resin layer positioned in a position overlapping with the release layer in the thickness direction, while leaving the cured resin layer positioned between the patterns of the release layer, wherein the release film has a thickness of 30 μm or more, the pure water contact angle on the surface of the release film facing the curable resin layer is 70.0° or more and 95.0° or less, and the release film contains a polyolefin resin or a polyester resin.

[0011] This disclosure provides a resin-impregnated decorative panel including a release film that achieves both the peelability of the release film and the ease of removing the cured resin layer on the release layer.

[0012] This is a schematic cross-sectional view illustrating a resin-impregnated decorative panel including a release film in this disclosure. This is a schematic cross-sectional view illustrating a release film and a resin-impregnated decorative panel in this disclosure. This is a schematic cross-sectional view illustrating a decorative sheet in this disclosure. This is a schematic cross-sectional view illustrating a decorative sheet in this disclosure. This is a schematic cross-sectional view illustrating a resin-impregnated decorative panel in this disclosure. This is a schematic cross-sectional view illustrating a method for manufacturing a resin-impregnated decorative panel including a release film in this disclosure. This is a schematic diagram illustrating a test apparatus for a 90° tensile test in this disclosure. This is a graph illustrating the test results of a 90° tensile test in this disclosure.

[0013] The embodiments will be described below with reference to the drawings, etc. However, this disclosure can be implemented in many different ways and is not limited to the embodiments described below. In addition, the drawings may schematically represent the width, thickness, and shape of each part compared to the actual form in order to make the explanation clearer, but this is merely an example and should not be interpreted as limiting.

[0014] In this specification, when describing a manner in which one member is placed on another member, the term "above" or "below" includes, unless otherwise specified, both cases: when the other member is placed directly above or directly below the member so as to be in contact with it, and when the other member is placed above or below the member via yet another member. Similarly, in this specification, when describing a manner in which one member is placed on the surface of a member, the term "on the surface" includes, unless otherwise specified, both cases: when the other member is placed directly above or directly below the member so as to be in contact with it, and when the other member is placed above or below the member via yet another member.

[0015] A. Resin-impregnated decorative panel including release film Figure 1 is a schematic cross-sectional view illustrating a resin-impregnated decorative panel including a release film in this disclosure. As shown in Figure 1, the resin-impregnated decorative panel 50 including a release film comprises a core substrate 20, a decorative sheet 10, a cured resin layer 30, and a release film 40, with the thickness direction D Ｔ In this order, the decorative sheet 10 has the thickness direction D Ｔ In this invention, the release film 40 has, in order from the core substrate 20 side, a porous substrate 1, a design layer 2, and a release layer 3 having a pattern shape. The decorative sheet 10 and the cured resin layer 30 also contain a cured product of a curable resin Y. In this disclosure, the thickness of the release film 40 is within a predetermined range. The pure water contact angle on the surface of the release film 40 facing the cured resin layer 30 is also within a predetermined range. Furthermore, the release film 40 contains a polyolefin resin or a polyester resin.

[0016] According to this disclosure, by setting the thickness of the release film and the pure water contact angle of the release film within a specific range, a resin-impregnated decorative panel including a release film is obtained that achieves both the peelability of the release film and the ease of removing the cured resin layer on the release layer. Furthermore, the release film peeled off from the resin-impregnated decorative panel is usually discarded as is. Therefore, by using a general-purpose resin such as a polyolefin resin or a polyester resin, costs can be reduced.

[0017] As described above, Patent Document 2 describes a method for producing a resin-impregnated decorative panel containing a release film (release sheet) by heat and pressure processing, and then peeling the release film from the resin-impregnated decorative panel to produce a resin-impregnated decorative panel with a gloss-matt finish. Specifically, as shown in Figure 2, when peeling off the release film 40, in areas where the release layer 3 is not formed, the release film 40 is peeled off from the cured resin layer 31. At the same time, in areas where the release layer 3 is formed, the release film 40 is peeled off together with the cured resin layer 32. This results in a resin-impregnated decorative panel 100 that expresses a gloss-matt finish due to the difference in gloss between the release layer 3 and the cured resin layer 31.

[0018] Thus, release films are required to selectively remove the cured resin layer on the release layer after heat and pressure processing. To selectively remove the cured resin layer on the release layer, controlling the adhesion between the release film and the cured resin layer is important. In particular, since a heat and pressure process is usually performed in the manufacture of resin-impregnated decorative panels, controlling the adhesion while considering the heat and pressure process is important. Therefore, in this disclosure, by focusing on the wettability of the release film and the thickness of the release film and controlling these, it is possible to achieve both the peelability of the release film and the ease of removing the cured resin layer on the release layer.

[0019] 1. Release Film In this disclosure, the release film is a component that is peeled off from the cured laminate (resin-impregnated decorative laminate including the release film) during the manufacturing of the resin-impregnated decorative laminate.

[0020] The release film contains a polyolefin resin or a polyester resin. Examples of polyolefin resins include olefin homopolymers, copolymers of two or more olefins, and copolymers of one or more olefins and one or more polymerizable monomers that can polymerize with olefins. Examples of the olefins (monomer units) include ethylene, propylene, butene, and hexene. The copolymer may be binary, ternary, or quaternary. The copolymer may also be a random copolymer or a block copolymer.

[0021] Specific examples of polyolefin resins include polyethylene resins and polypropylene resins, with polypropylene resins being preferred. An example of a polypropylene resin is a propylene homopolymer. Another example of a polypropylene resin is a copolymer of propylene and another α-olefin. Examples of other α-olefins include at least one of ethylene, butene-1, hexene-1, and heptene-1,4-methylpentene-1. It is preferable that polypropylene resins have propylene as the main monomer unit. Similarly, it is preferable that polyethylene resins have ethylene as the main monomer unit.

[0022] Examples of polyester resins include condensation polymers of compositions containing at least dicarboxylic acids and diols. The above compositions may also contain other monomers polymerizable with dicarboxylic acids or diols. Examples of dicarboxylic acids include terephthalic acid and 2,6-naphthalenedicarboxylic acid. Examples of diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,4-cyclohexanedimethanol. Specific examples of polyester resins include polyethylene terephthalate and polybutylene terephthalate.

[0023] The side of the release film facing the cured resin layer is referred to as the first surface. The pure water contact angle on the first surface of the release film is usually 70.0° or higher, but may be 75.0° or higher, or 80.0° or higher. If the pure water contact angle is too small, the adhesion between the release film and the cured resin layer will be excessively high, which may make it difficult to peel the release film from the cured resin layer. On the other hand, the pure water contact angle on the first surface of the release film is usually 95.0° or lower, but may be 90.0° or lower. If the pure water contact angle is too large, the adhesion between the release film and the cured resin layer will be excessively low, which may make it difficult to remove the cured resin layer on the release layer.

[0024] The pure water contact angle on the first surface of the release film is determined by measuring the first surface of the release film after peeling the release film off the resin-impregnated decorative board containing the release film. Specifically, the pure water contact angle is the value obtained by measuring it using the following method.

[0025] That is, the release film is placed still on a horizontal plane such that the first surface of the release film becomes the upper surface. Next, water droplets (pure water, 2.0 μL) are dropped onto the release film from the vertical direction with respect to the horizontal plane. At this time, the water droplets are not dropped onto the cured resin layer present on the first surface, and all of the water droplets are dropped so as to contact the first surface where the cured resin layer does not exist. After the water droplets are dropped, wait for 10 seconds, and using a contact angle meter, measure the contact angle between the release film and pure water. The above measurement is performed at any 10 locations, and the average value thereof is taken as the pure water contact angle on the first surface of the release film.

[0026] The first surface of the release film may or may not be surface-treated on the condition that the pure water contact angle satisfies the above-described range. Examples of the surface treatment include embossing treatment and sand matting treatment. Here, for example, a release film that is not surface-treated has the advantage of being inexpensive. When manufacturing a resin-impregnated decorative board, the release film peeled off from the cured laminate (resin-impregnated decorative board including the release film) is usually discarded as it is, and thus, by using an inexpensive release film, the manufacturing cost can be reduced. The release film may or may not contain a matting agent on the condition that the pure water contact angle on the first surface satisfies the above-described range. Similarly, the release film may or may not contain a release agent on the condition that the pure water contact angle on the first surface satisfies the above-described range. For example, a release film that does not contain a matting agent or a release agent is inexpensive and can reduce the manufacturing cost. Further, the first surface of the release film may not be provided with a coating layer having releasability. In other words, the main body of the release film may constitute the first surface. A release film that does not have a coating layer having releasability is inexpensive and can reduce the manufacturing cost.

[0027] The release film preferably has a melting point such that it does not melt in the heat-pressing process described below. The melting point of the release film is, for example, 130°C or higher, and may be 140°C or higher, or may be 150°C or higher. The melting point of the release film is, for example, 270°C or lower. The method for measuring the melting point of the release film is as follows. - Measuring device... Differential scanning calorimeter (DSC) - Measuring standard... JIS K7121-1987 - Measuring procedure 1) Cut out from the release film and collect about 5 mg, put it into the measurement container (pan) of the DSC, and place it in the device. 2) Prepare α-alumina as a reference substance and place it in the device as well. 3) Under a nitrogen atmosphere, heat from room temperature to a temperature 30°C higher than the melting temperature of the release film at a heating rate of 10°C / min, and then maintain the temperature for 10 minutes. 4) Cool down to 40°C at a cooling rate of 10°C / min, and then heat again to the temperature heated in 3) under the same heating conditions as in 3). 5) Obtain the melting point temperature by reading the horizontal axis (temperature) of the endothermic peak (a peak convex downward) of the DSC curve obtained during the heating in 4). When there are multiple endothermic peaks, adopt the temperature obtained from the one with the largest endothermic peak area.

[0028] The thickness of the release film is usually 30 μm or more, and may be 40 μm or more. If the release film is too thin, it may not be possible to ensure the mechanical strength that is a prerequisite for controlling the adhesion. On the other hand, the thickness of the release film is, for example, 100 μm or less.

[0029] 2. Cured resin layer The cured resin layer is disposed between the decorative sheet and the release film. Also, the cured resin layer is disposed so as to overlap the design layer and the release layer in the decorative sheet when viewed from the thickness direction. Further, the cured resin layer contains a cured product of the curable resin Y. In the present disclosure, the precursor layer (layer before curing) of the cured resin layer may sometimes be referred to as a curable resin layer.

[0030] Examples of curable resin Y include thermosetting resins. 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.

[0031] As shown in Figure 1, the thickness of the cured resin layer 30 may be greater than the thickness of the release layer 3. The thickness of the cured resin layer 30 is not particularly limited, but for example, it may be 1 μm or more and 500 μm or less, or 10 μm or more and 300 μm or less. Also, the thickness T of the cured resin layer 30 present on the release layer 3. １ For example, the thickness T may be 0.5 μm or more and 45 μm or less, 2 μm or more and 35 μm or less, or 3 μm or more and 30 μm or less. １ This corresponds, for example, to the difference between the thickness of the cured resin layer 31 and the thickness of the release layer 3, as shown in Figure 2.

[0032] As shown in Figure 1, when the release film 40 is peeled off from the resin-impregnated decorative panel 50 containing the release film, a resin-impregnated decorative panel 100 is obtained, as shown in Figure 2, having a release layer 3 having a pattern shape and a cured resin layer 31 arranged between the patterns of the release layer 3. The 60° gloss value of the cured resin layer 31 may be greater than the 60° gloss value of the release layer 3. The 60° gloss value of the cured resin layer 31 may be, for example, 11 or more, 15 or more, or 20 or more. On the other hand, the 60° gloss value of the cured resin layer 31 may be, for example, 60 or less, 55 or less, or 50 or less. Also, the difference between the 60° gloss value of the cured resin layer 31 and the 60° gloss value of the release layer 3 may be, for example, 1.0 or more, or 3.0 or more. Also, the ratio of the 60° gloss value of the cured resin layer 31 to the 60° gloss value of the release layer 3 may be, for example, 1.2 or more, or 1.5 or more.

[0033] 3. Decorative Sheet As shown in Figure 3, the decorative sheet 10 consists of a porous base material 1, a design layer 2, and a release layer 3 having a pattern shape, in the thickness direction DＴ In this order, they are present.

[0034] (1) Release layer In this disclosure, the release layer is arranged on the side opposite to the porous substrate of the design layer and has a pattern shape. In the region where the design layer is on the porous substrate, at least a portion of the release layer is arranged on the side opposite to the porous substrate of the design layer, and in the region where the design layer is not on the porous substrate, the porous substrate and the release layer may be in contact.

[0035] (i) The resin-molded release layer contains a resin component. The resin component is typically a cured product (crosslinked structure) of a curable resin X. On the other hand, the resin component may also be a thermoplastic resin. In particular, it is preferable that the release layer contains a cured product of a curable resin X, because this provides a release layer with good abrasion resistance. Furthermore, the inclusion of a cured product of a curable resin X in the release layer improves its release properties from the cured resin layer.

[0036] Examples of curable resins X include ionizing radiation-curable resins and thermosetting resins. Examples of ionizing radiation-curable resins include electron beam-curable resins and ultraviolet-curable resins. Ionizing radiation-curable resins (ionizing radiation-curable compounds) are not limited to materials that undergo a crosslinking polymerization reaction upon irradiation with ionizing radiation and change into a three-dimensional polymer structure. Examples of ionizing radiation-curable resins include prepolymers, oligomers, and monomers having polymerizable unsaturated bonds or epoxy groups in their molecules that can be crosslinked upon irradiation with ionizing radiation. In this disclosure, only one type of ionizing radiation-curable resin may be used, or two or more types may be used. In particular, it is preferable to use at least one of a polyfunctional monomer and an oligomer as the ionizing radiation-curable resin.

[0037] Examples of ionizing radiation-curable resins include (meth)acrylate resins such as urethane (meth)acrylate, ester (meth)acrylate, and epoxy (meth)acrylate; silicon-based resins such as siloxane; ester-based resins; and epoxy-based resins. (Meth)acrylate resins refer to acrylate-based resins or methacrylate-based resins.

[0038] The weight-average molecular weight of the ionizing radiation-curable resin is, for example, 500 or more and 80,000 or less, and may also be 1,000 or more and 50,000 or less. The weight-average molecular weight is a value measured using gel permeation chromatography (GPC) with polystyrene as the standard substance.

[0039] The ionizing radiation-curable resin preferably contains at least a polyfunctional monomer or oligomer having a weight-average molecular weight of 500 or more. Examples of such polyfunctional monomers or oligomers include (meth)acrylate resins such as dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, urethane(meth)acrylate, ester(meth)acrylate, and epoxy(meth)acrylate.

[0040] On the other hand, examples of thermosetting resins include unsaturated ester resins, urethane resins (including two-component curing polyurethanes), epoxy resins, aminoalkyd resins, phenolic resins, urea resins, diallyl phthalate resins, melamine resins, guanamine resins, melamine-urea cocondensation resins, silicon resins, and siloxane resins.

[0041] (ii) The matting agent release layer may contain a matting agent. Using a matting agent can provide a low-gloss release layer. Examples of matting agents include inorganic particles and synthetic resin particles. Examples of inorganic particles include silica, alumina, calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, and kaolin. Examples of synthetic resin particles include acrylic beads, urethane beads, nylon beads, silicone beads, silicone rubber beads, polycarbonate beads, and polyolefin waxes (e.g., polypropylene wax, polyethylene wax).

[0042] The matting agent content is, for example, 5 parts by mass or more and 20 parts by mass or less, and may be 8 parts by mass or more and 18 parts by mass or 10 parts by mass or more and 15 parts by mass or less, based on 100 parts by mass of the total solid content of the release layer.

[0043] (iii) Release agent The release layer may contain a release agent. Adding a release agent improves release properties. Examples of release agents include silicone-based release agents such as silicone oil, wax-based release agents such as polyolefin wax, and fluorine-based release agents. Among these, silicone oil is preferred because it has excellent heat resistance in the heating and pressurizing process. The silicone oil may be reactive silicone oil or non-reactive silicone oil, but reactive silicone oil is preferred because it has even better heat resistance.

[0044] Reactive silicone oil refers to modified silicone oils in which organic groups have been introduced into the side chains or terminals, and which exhibit reactivity depending on the properties of the introduced organic groups. Specifically, examples of reactive silicone oils include modified silicone oil side chain type, modified silicone oil both-ended type, modified silicone oil single-ended type, and modified silicone oil side chain both-ended type, in which the introduced organic groups are amino-modified, epoxy-modified, mercapto-modified, carboxyl-modified, carbinol-modified, phenol-modified, methacrylic-modified, heterofunctional group-modified, etc. These reactive silicone oils can be used individually or in mixtures of two or more types.

[0045] Non-reactive silicone oils are not particularly limited as long as they do not have reactive functional groups such as amino groups, epoxy groups, mercapto groups, carboxyl groups, hydroxyl groups, (meth)acryloyl groups, or allyl groups. Examples of non-reactive silicone oils include silicone oils made from polysiloxane, as well as polyether-modified silicone oils, aralkyl-modified silicone oils, fluoroalkyl-modified silicone oils, long-chain alkyl-modified silicone oils, higher fatty acid ester-modified silicone oils, higher fatty acid amide-modified silicone oils, and phenyl-modified silicone oils. These non-reactive silicone oils can be used individually or in combination of two or more types.

[0046] The amount of release agent is, for example, 1 part by mass or more and 10 parts by mass or less per 100 parts by mass of the total solid content of the release layer, and may be 2 parts by mass or more and 9 parts by mass or less, or 3 parts by mass or more and 8 parts by mass or less.

[0047] Furthermore, the release layer may be colorless or colored. In the latter case, it is preferable that the release layer contains a coloring agent. The same coloring agent used in the design layer described later can be used. In addition, the release layer may contain additives such as ultraviolet absorbers, infrared absorbers, light stabilizers, polymerization inhibitors, crosslinking agents, antistatic agents, antioxidants, leveling agents, coupling agents, plasticizers, defoaming agents, fillers, thermal radical generators, and aluminum chelating agents, as needed. Adding an ultraviolet absorber or a light stabilizer can improve the weather resistance of the release layer.

[0048] (iv) Release layer The pure water contact angle of the release layer is not particularly limited, but for example it may be 85° or more and 130° or less, or 90° or more and 125° or less. The pure water contact angle of the release layer is determined by measuring the surface of the release layer exposed by peeling off the release film from the resin-impregnated decorative board containing the release film. Specifically, the pure water contact angle of the release layer is the value obtained by measuring it using the following method.

[0049] Specifically, the resin-impregnated decorative panel is placed on a horizontal surface so that the release layer exposed by peeling off the release film is on the top surface. Next, a water droplet (pure water, 2.0 μL) is dropped onto the release layer from a direction perpendicular to the horizontal surface. At this time, the water droplet is not dropped at the boundary between the cured resin layer and the release layer, but is dropped so that the entire water droplet is in contact with the release layer. After dropping the water droplet, wait for 1 second and measure the contact angle between the release layer and the pure water using a contact angle meter. Perform the above measurement at 10 arbitrary locations, and the average value is taken as the pure water contact angle of the release layer.

[0050] The pure water contact angle can be adjusted by the amount of release agent and the thickness of the release layer. For example, increasing the amount of release agent can increase the pure water contact angle. For example, increasing the thickness of the release layer can also increase the pure water contact angle.

[0051] The Spc (arithmetic mean curvature of peak points) of the release layer is not particularly limited. For example, it is 10 mm －１ or more and 140 mm －１ or less, and it may be 15 mm －１ or more and 120 mm －１ or less, and it may also be 20 mm －１ or more and 100 mm －１ or less. The Spc of the release layer can be obtained by measuring the surface of the release layer exposed by peeling off the release film from the resin-impregnated decorative board including the release film.

[0052] Spc (arithmetic mean curvature of peak points) is one of the three-dimensional surface property parameters defined in ISO 25178, and it is the average curvature (average sharpness) of the tip of the peak, which is obtained from the arithmetic mean value of the curvature radii of the peak points (peak vertices) classified as mountains (convex parts) in the shape image included in the reference area. Therefore, Spc (arithmetic mean curvature of peak points) is the reciprocal of the radius (mm －１ ). The larger the value of Spc (arithmetic mean curvature of peak points), the larger the curvature of the tip of the peak (convex part) becomes (the curvature radius of its reciprocal is smaller, and the shape of the tip becomes sharper). On the other hand, the smaller the value of Spc (arithmetic mean curvature of peak points), the smaller the curvature of the peak point (top of the protrusion) becomes (the curvature radius of its reciprocal is larger, and the shape of the tip becomes blunter).

[0053] The Spc (arithmetic mean curvature of peak points) of the release layer is the average value of the measured values obtained by using a laser microscope manufactured by Keyence Corporation and selecting the measurement part so that all of the measurement parts enter the release layer and measuring at any 10 locations under the following conditions with respect to the surface of the release layer. (Measurement conditions) Objective lens: 5 times Laser wavelength: 661 nm Measurement area area of each point: 500 μm × 500 μm

[0054] Spc can be adjusted, for example, by the particle size of the matting agent. Specifically, Spc can be increased by increasing the particle size of the matting agent. Also, Spc can be increased by increasing the content of the matting agent.

[0055] The 60° gloss value of the release layer is not particularly limited, but for example, it may be 10 or less, 8 or less, or 7.5 or less. When the 60° gloss value of the release layer is adjusted to a low value, the release layer functions as a matte area. The 60° gloss value of the release layer may be, for example, 1.0 or more, 2.0 or more, or 3.0 or more.

[0056] The 60° gloss value of the release layer can be determined by measuring the surface of the release layer exposed by peeling off the release film from the resin-impregnated decorative laminate containing the release film. The 60° gloss value of the release layer is the 60° specular gloss measured according to Method 3 of JIS Z 8741:1997, and is determined as the average value of measurements taken at 10 arbitrary locations. The 60° gloss value of the release layer can be adjusted by the particle size of the matting agent, the content of the matting agent, and the thickness of the release layer.

[0057] Furthermore, as shown in Figure 4, it is preferable that the release layer 3 is arranged in synchronization with the pattern of the design layer 2. "Synchronization" means that the shapes and positions of the two patterns in question are roughly the same. Specifically, it means that the shapes and positions of the release layer pattern and at least some of the patterns constituting the design layer's pattern are consistent to an extent that does not impair realism and a sense of luxury. In Figure 4, the design layer 2 has a pattern layer y1 and a pattern layer y2, and the release layer 3 is synchronized with the pattern layer y1. By arranging the release layer pattern in synchronization with the design layer's pattern, a high-quality texture can be obtained. On the other hand, the release layer does not necessarily have to be arranged in synchronization with the design layer's pattern.

[0058] The thickness of the release layer is not particularly limited, but for example, it may be 0.1 μm or more and 20 μm or less, 0.3 μm or more and 10 μm or less, or 0.5 μm or more and 8 μm or less. The thickness of the release layer refers to the thickness of the portion that does not penetrate to the design layer side and protrudes from the side opposite to the porous substrate of the design layer 2. Also, when viewing the decorative sheet from the thickness direction, the area of ​​the release layer is S. １ The area of ​​the porous substrate is S ２ In that case, S ２ S for １ The proportion (S１ / S ２ ) is, for example, 5% or more, and may be 10% or more. On the other hand, S １ / S ２ For example, it may be 80% or less, 70% or less, or 60% or less.

[0059] The method for forming the release layer is not particularly limited, but one example is to coat a release layer forming ink containing a curable resin X onto the surface opposite to the porous substrate of the design layer and cure it. For example, if the release layer forming ink contains an electron beam curable resin as the curable resin X, a cured product of the electron beam curable resin is usually obtained by irradiating it with an electron beam. Examples of electron beam sources include various electron beam accelerators such as Cockcroftwald type, Van de Graft type, resonant transformer type, insulated core transformer type, linear type, Dynamitron type, and high-frequency type. The energy of the electron beam is, for example, 100 kV or more and 1000 kV or less, and may also be 100 kV or more and 300 kV or less. The electron beam irradiation dose is, for example, 2 Mrad or more and 15 Mrad or less.

[0060] (2) Design layer The design layer in this disclosure is disposed on one side of the porous substrate. The design layer preferably has a pattern.

[0061] Examples of patterns in the design layer include organic patterns, inorganic patterns, and abstract patterns. Organic patterns are those derived from the life activities of living things such as plants and animals. Inorganic patterns are those that do not fall under the category of organic patterns. Abstract patterns are those that interpret a subject (for example, a form existing in nature) abstractly and do not represent a clear shape. Examples of organic patterns include wood grain patterns, leather patterns, floral patterns, and botanical patterns. Examples of inorganic patterns include stone patterns, concrete patterns, sand patterns, fabric patterns, metal patterns, tile patterns, and brick patterns. Examples of abstract patterns include wavering patterns (for example, wavering ink patterns), smoke patterns, and marble patterns.

[0062] The design layer, for example, has a pattern layer. The design layer may also have a solid layer on the porous substrate side of the pattern layer. In this disclosure, the pattern layer means a layer formed partially (particularly in a pattern) on one surface of the porous substrate. The solid layer means a layer formed over the entire surface of one surface of the porous substrate.

[0063] The design layer contains, for example, a coloring agent and a resin component. Examples of coloring agents include inorganic pigments such as carbon black, titanium white, zinc oxide, red iron oxide, Prussian blue, and cadmium red; organic pigments such as azo pigments, lake pigments, anthraquinone pigments, quinacridone pigments, phthalocyanine pigments, isoindolinone pigments, and dioxazine pigments; metallic powder pigments such as aluminum powder and bronze powder; pearlescent pigments such as titanium dioxide-coated mica and bismuth oxide; fluorescent pigments; and phosphorescent pigments. Dyes may also be used as coloring agents.

[0064] Examples of resin components include (meth)acrylic resins, ester urethane resins, acrylamide resins, ethylene oxide resins, N-vinylpyrrolidone resins, ester resins, amide resins, vinyl acetate resins, vinyl chloride resins, urethane (meth)acrylic resins, natural rubber, and synthetic rubber. Among these, (meth)acrylic resins and urethane (meth)acrylic resins are preferred.

[0065] The design layer preferably contains a resin having one or more polar groups, such as a hydroxyl group, an amino group, and a carboxyl group, as a resin component. The inclusion of a resin having the above polar groups improves the impregnation of the curable resin Y into the porous substrate.

[0066] Resins containing polar groups include hydroxyl groups (-OH) and amino groups (-NH). ２ It contains one or more of the following: a hydroxyl group (-OH), or a carboxyl group (-COOH). The above polar groups may be ionized and stabilized by the influence of the solvent and other functional groups, for example. Therefore, the above "hydroxyl group (-OH)" is in an ionized state as "-O － This is a concept that includes the above "amino group (-NH ２ ) is the ionized state "-NH３ ＋ The concept includes "carboxy group (-COOH)", and the ionized state is "-COOH － This is a concept that includes "[...]."

[0067] Hydroxyl group (-OH), amino group (-NH) ２ Examples of resins having one or more polar groups, such as carboxyl groups (-COOH), include aqueous proteins such as casein, cellulose, acetylcellulose, nitrated cotton, hydroxypropylcellulose, carboxymethylcellulose, and other cellulose derivatives, polyvinyl alcohol, polyvinyl alcohol derivatives such as polyvinyl butyral resin, amino resins such as melamine resin, (meth)acrylic acid resins, phenolic resins, acrylic polyols, and natural polymers (e.g., polynucleotides, polypeptides, polysaccharides).

[0068] The design layer preferably contains one or more of the following polar group-containing resins: casein, melamine resin, polyvinyl alcohol, polyvinyl alcohol derivatives, cellulose, and cellulose derivatives, and more preferably casein. As the casein, α-casein, β-casein, γ-casein, or mixtures thereof can be used. In addition, derivatives such as sodium caseinate and ammonium caseinate can be used alone or in combination as the casein.

[0069] The proportion of the resin having polar groups described above to the resin components contained in the design layer is, for example, 20% by mass or more, may be 30% by mass or more, may be 40% by mass or more, or may be 50% by mass or more. On the other hand, the above proportion of the resin having polar groups is, for example, 100% by mass or less, or may be 90% by mass or less. If the content of the resin having polar groups is within the above range, the penetration of the ink in the release layer into the porous substrate can be further suppressed without hindering the penetration of the curable resin Y into the porous substrate.

[0070] The design layer may contain additives such as fillers (e.g., silica), extender pigments (e.g., organic beads), neutralizing agents, and surfactants, as needed. The thickness of the design layer is not particularly limited, but is, for example, 0.1 μm or more and 20 μm or less.

[0071] One method for forming a design layer is a coating method using an ink for forming a design layer that contains a colorant, a binder resin, and a solvent (or dispersion medium). For example, a design layer can be obtained by coating one side of a porous substrate with the ink for forming a design layer and drying it.

[0072] (3) Porous Substrate The porous substrate in this disclosure is a substrate into which a curable resin Y is impregnated during the manufacture of a resin-impregnated decorative board. 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 paper 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. 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 impregnation properties with the curable resin Y. In particular, titanium paper is preferred as a porous substrate because it has excellent impregnation properties with the curable resin Y and also has excellent opacity.

[0073] Porous substrates may be colored. For example, a colored porous substrate can be obtained by incorporating a coloring agent during the manufacturing stage 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 stage. 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. Furthermore, the porous substrate may contain various additives as needed, such as fillers, matting agents, foaming agents, flame retardants, lubricants, antistatic agents, antioxidants, ultraviolet absorbers, and light stabilizers.

[0074] The basis weight of the porous substrate is not particularly limited, but for example, 40 g / m² ２ Above, 150g / m ２ The 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, in order to improve the adhesion of the ink forming the design layer, the surface of the porous substrate facing the design layer may be subjected to corona treatment.

[0075] 4. Core Substrate The core substrate in this disclosure is arranged on the porous substrate side of the decorative sheet (the side of the decorative sheet located on the porous substrate side with respect to the design layer). By providing a core substrate, the mechanical strength of the resin-impregnated decorative panel can be increased. Examples of core substrates include phenol resin-impregnated paper. Phenolic resin-impregnated paper is, for example, paper obtained by impregnating kraft paper, which is the core paper, with phenol resin and drying it. The core substrate may also contain a cured product of a curable resin Y.

[0076] 5. Resin-impregnated decorative panel including release film In this disclosure, the resin-impregnated decorative panel including release film has the core substrate, decorative sheet, cured resin layer, and release film in this order in the thickness direction. Also, as shown in Figure 2, the resin-impregnated decorative panel 100 is obtained by peeling off the release film 40 from the resin-impregnated decorative panel 50 including release film. The resin-impregnated decorative panel 100 can express a gloss-matt finish due to the difference in gloss between the release layer 3 and the cured resin layer 31. Also, as shown in Figure 5, the resin-impregnated decorative panel 100 has a thickness direction D Ｔ From this perspective, the region where the release layer 3 exists may be designated as a matte region, and the region where the cured resin layer 31 exists (the region where the release layer 3 does not exist) may be designated as a gloss region.

[0077] In a 90° tensile test to peel the release film from a resin-impregnated decorative laminate containing the release film, the integral mean load when the release film is pulled at a speed of 100 mm / min is not particularly limited, but is preferably between 0.1 N and 4.0 N. Details of the 90° tensile test are described in the examples.

[0078] Resin-impregnated decorative panels are used, for example, by being placed on the surface of a substrate. Examples of substrates include wood-based materials, resin-based materials, metal-based materials, and ceramic-based materials. Examples of wood-based materials include wood veneer, wood plywood, particleboard, and wood fiberboard. Examples of wood used in wood-based materials include cedar, cypress, pine, and lauan. Examples of resins used in resin-based materials include vinyl chloride resin, (meth)acrylic resin, ester resin, styrene resin, olefin resin, acrylonitrile-butadiene-styrene copolymer (ABS resin), phenolic resin, cellulose resin, carbonate resin, melamine resin, and rubber. Examples of metals used in metal-based materials include iron and aluminum. The material of the ceramic-based material may be ceramics such as glass and porcelain, non-cement ceramic materials such as gypsum, or non-ceramic ceramic materials such as ALC (autoclaved lightweight concrete).

[0079] Applications of resin-impregnated decorative panels include, for example, building materials and furniture. Building materials may be interior or exterior materials. Examples of building materials include walls, floors, ceilings, doors, and shelves. Examples of furniture include tables, desks, and cabinets.

[0080] B. Release Film As shown in Figure 2, the release film 40 in this disclosure comprises a core substrate 20, a decorative sheet 10, and a cured resin layer 31, with the thickness direction D Ｔ In this context, the resin-impregnated decorative sheet 100 is used in the manufacture of the decorative sheet 10 having the following characteristics in this order. The decorative sheet 10 has a thickness direction D Ｔ In this invention, the core substrate 20 side is in order to have a porous substrate 1, a design layer 2, and a release layer 3 having a pattern shape. The decorative sheet 10 and the cured resin layer 31 also contain a cured product of a curable resin Y. The cured resin layer 31 is also arranged between the patterns of the release layer 3. In this disclosure, the thickness of the release film 40 is within a predetermined range. The pure water contact angle on the surface of the release film 40 facing the cured resin layer 31 is also within a predetermined range. Furthermore, the release film 40 contains a polyolefin resin or a polyester resin.

[0081] According to this disclosure, by setting the thickness of the release film and the pure water contact angle of the release film within a specific range, a release film can be made that achieves both peelability and ease of removal of the cured resin layer on the release layer. Furthermore, by using general-purpose resins such as polyolefin resins or polyester resins, costs can be reduced. Details of the release film are the same as those described in "A. Resin-impregnated decorative boards containing release film" above.

[0082] According to JIS B0601:2013, the arithmetic mean roughness (Ra) of the first surface of the release film is, for example, 0.50 μm or less, may be 0.45 μm or less, or 0.40 μm or less. On the other hand, the arithmetic mean roughness (Ra) of the first surface of the release film is, for example, 0.01 μm or more, or 0.02 μm or more. Ra (arithmetic mean roughness) is one of the parameters in the height direction of the contour curve, and is the average value of the height difference from the average surface in the contour curve at a reference length. The smaller the value of Ra (arithmetic mean roughness), the smaller the height difference between the convex and concave parts on the first surface, and is an indicator that tends to result in a smoother and more uniform shape.

[0083] According to JIS B0601:2013, the Rz (maximum height) of the first surface of the release film is, for example, 4.0 μm or less, and may be 3.5 μm or less. On the other hand, the Rz (maximum height) of the first surface of the release film is, for example, 0.1 μm or more. Rz (maximum height) is one of the peak and height parameters of the contour curve, and is the sum of the height of the highest peak and the depth of the deepest valley in the contour curve at a reference length. A larger Rz (maximum height) value indicates the presence of large (high) convex parts when viewed from the valleys (concave parts), and that there is a tendency for many such convex parts to be present.

[0084] According to JIS B0601:2013, the RSm (average length of curved elements) of the first surface of the release film is, for example, 0.2 mm or less, and may be 0.15 mm or less. On the other hand, the RSm (average length of curved elements) of the first surface of the release film is, for example, 0.03 mm or more, and may be 0.05 mm or more. RSm (average length of curved elements) is a lateral parameter of the contour curve and is the average length of the contour curve elements in the reference length. The smaller the RSm, the more convex parts are included in the reference length.

[0085] C. Method for Manufacturing Resin-Impregnated Decorative Panels The method for manufacturing resin-impregnated decorative panels in this disclosure comprises a preparation step, a laminate formation step, a heating and pressurizing step, and a peeling step, as described later. In this disclosure, the thickness of the release film is within a predetermined range. In addition, the pure water contact angle on the side of the release film facing the curable resin layer is within a predetermined range. Furthermore, the release film contains a polyolefin resin or a polyester resin.

[0086] According to this disclosure, by using a specific release film, it is possible to achieve both the peelability of the release film and the ease of removing the cured resin layer on the release layer, thereby enabling the efficient manufacture of resin-impregnated decorative panels that express a glossy-matt finish.

[0087] 1. Preparation Process The preparation process in this disclosure involves, as shown in Figure 6(a), a porous substrate 1, a design layer 2, and a release layer 3 having a pattern shape, in the thickness direction D Ｔ The next step is to prepare a decorative sheet 10 having the decorative sheet in this order. Details of the decorative sheet are the same as those described in "A. Resin-impregnated decorative board including release film" above.

[0088] 2. Laminate Formation Process The laminate formation process in this disclosure is as shown in Figure 6(d): (i) a core substrate 20, a decorative sheet 10, a curable resin layer 30a containing curable resin Y, and a release film 40, in the thickness direction D Ｔ The process involves forming a laminate 52 having the following characteristics in this order: (ii) the surface of the decorative sheet 10 facing the porous substrate 1 is arranged to face the core substrate 20, and (iii) the decorative sheet 10 is impregnated with a curable resin Y.

[0089] The method for forming the laminate is not particularly limited. For example, as shown in Figures 6(b) and 6(c), first, a curable resin layer 30a containing the curable resin Y is formed by impregnating the decorative sheet 10 with the curable resin Y (Figure 6(b)), covering the design layer 2 and the release layer 3, thereby obtaining a precursor laminate 51 (Figure 6(c)). Next, as shown in Figure 6(d), a release film 40 is placed on the side of the precursor laminate 51 facing the curable resin layer 30a, and a core substrate 20 is placed on the side of the precursor laminate 51 facing the porous substrate 1. This gives rise to a laminate 52. Details of the core substrate 20, curable resin Y, and release film 40 are the same as those described in "A. Resin-impregnated decorative board including release film" above.

[0090] In the laminate formation process, for example, a decorative sheet is immersed in a curable resin composition containing curable resin Y. After immersion, drying is preferable. At this time, a portion of the curable resin may be cured, leaving it in a semi-cured state. The curable resin composition is a curable resin composition containing curable resin Y. The proportion of curable resin Y in the curable resin composition is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. The curable resin composition may contain solvents such as water, alcohol, or organic solvents.

[0091] Another example of a method for forming a laminate is to place a core substrate opposite to a porous substrate in a decorative sheet, impregnate the core substrate and the porous substrate with a curable resin Y, cover the design layer and the release layer, and form a curable resin layer containing the curable resin Y, and then place a release film on the side of the curable resin layer.

[0092] 3. Heating and Pressurizing Process The heating and pressing process in this disclosure is a process in which the laminate 52 is heated and pressurized, as shown in Figure 6(e), to cure the curable resin Y, form a cured resin layer 30 from the curable resin layer 30a, and obtain a cured laminate 53. The cured laminate 53 corresponds to the resin-impregnated decorative board containing the release film as described above.

[0093] The heating temperature is not particularly limited, but for example, it is between 90°C and 160°C. The heating time is also not particularly limited, but for example, it is between 30 seconds and 30 minutes.

[0094] 4. Peeling Process The peeling process in this disclosure involves peeling the release film 40 from the cured laminate 53, as shown in Figure 6(f), in the thickness direction D Ｔ This process involves removing the hardened resin layer 30 positioned in a location that overlaps with the release layer 3, while leaving the hardened resin layer 30 (hardened resin layer 31) positioned between the patterns of the release layer 3. This results in a resin-impregnated decorative panel 100.

[0095] 5. Resin-impregnated decorative laminates The resin-impregnated decorative laminates obtained by each of the above processes are the same as those described in "A. Resin-impregnated decorative laminates including release film" above.

[0096] 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.

[0097] [Preparation of Release Films] Release films 1 to 9 (RF1 to 9) were prepared, differing in material, thickness, and whether or not they had surface treatment. Release films 1 to 3, 6, 7, and 9 were made of polyethylene terephthalate (PET), release films 4 and 8 were made of polypropylene (PP), and release film 5 was made of polyethylene (PE). As shown in Tables 1 and 2, the minimum thickness of release films 1 to 9 was 27 μm for release film 6, and the maximum was 98 μm for release films 4 and 8. Release films 1 to 6 were untreated films. On the other hand, release films 7 and 8 were corona treated, and release film 9 was coated with a release agent containing a silicone-based release agent.

[0098] Furthermore, the pure water contact angle of the first surface (the surface facing the cured resin layer in the resin-impregnated decorative board) of release films 1 to 9 was measured by the following method. The release film was placed on a horizontal surface with the first surface facing upwards. Next, a water droplet (pure water, 2.0 μL) was dropped onto the first surface from a direction perpendicular to the horizontal plane. After dropping the water droplet, a 10-second wait was made, and the contact angle between the first surface and the pure water was measured using a contact angle meter (fully automatic contact angle meter DMo-702, manufactured by Kyowa Interface Science Co., Ltd.). The above measurement was performed at 10 arbitrary locations, and the average value was taken as the pure water contact angle. The results are shown in Tables 1 and 2.

[0099] Furthermore, the melting points of release films 1 to 9 were measured using a differential scanning calorimeter (DSC) in accordance with JIS K7121-1987. Specifically, approximately 5 mg was taken from the release film, placed in the DSC measurement container (pan), and positioned in the apparatus. Next, α-alumina was prepared as a reference material and also placed in the apparatus. Then, under a nitrogen atmosphere, the temperature was raised from room temperature at a heating rate of 10°C / min to 30°C higher than the melting temperature of the release film, and the temperature was maintained for 10 minutes. Next, the temperature was lowered to 40°C at a cooling rate of 10°C / min, and then heated to the temperature raised above under the same heating conditions as above. The melting point temperature was obtained by reading the horizontal axis (temperature) of the endothermic peak (downward-convex peak) of the DSC curve obtained during the heating process. The results are shown in Tables 1 and 2.

[0100]

[0101]

[0102] [Examples 1-5, Comparative Examples 1-4] (Preparation of decorative sheets) As a porous substrate, a paper-based substrate (basis weight 80 g / m²) was used. ２Titanium base paper for building materials (PM-77P, manufactured by KJ Specialty Paper Co., Ltd.) was prepared. Using the following printing inks, a 2 μm thick design layer (pattern layer) was partially laminated onto the paper substrate using a gravure printing method to create a stone-like pattern. Furthermore, the following release layer forming ink was laminated on top of the pattern layer in synchronization with the pattern layer, and then an 8 μm thick release layer was formed by irradiating with an electron beam at 3 Mrad with an accelerating voltage of 165 kV. In this way, a decorative sheet was manufactured in which the porous substrate, design layer, and release layer were laminated in this order.

[0103] <Printing Ink> • Pigments (azo, quinacridone, carbon black, etc.) 10 parts by mass • Casein / acrylic resin 10 parts by mass • Water 70 parts by mass • Dipropyl glycol 5 parts by mass • Isopropyl alcohol 5 parts by mass

[0104] <Ink for forming a release layer> ・Ionizing radiation-curable monomer (Toagosei Co., Ltd., Aronics M-400) 48 parts by mass ・Reactive silicone (Shin-Etsu Chemical Co., Ltd., X-22-164B) 4 parts by mass (6.7 parts by mass per 100 parts by mass of total solids) ・Silane coupling treated silica (particle size 2 μm) 8 parts by mass (13.3 parts by mass per 100 parts by mass of total solids) ・Methyl ethyl ketone 40 parts by mass

[0105] (Manufacturing of melamine decorative laminate) A liquid uncured melamine resin composition containing 60 parts by mass of uncured melamine resin (water-soluble methylol melamine resin, Nikaredin S-260 manufactured by Nippon Carbide Industries Co., Ltd.), 35 parts by mass of water, and 5 parts by mass of isopropyl alcohol is impregnated into the prepared decorative sheet using an impregnation device until the uncured melamine resin composition reaches 80 g / m². ２ The material was impregnated to the ratio specified (when dry), dried, and then an impregnated decorative sheet (precursor laminate) was manufactured.

[0106] The impregnated decorative sheet was manufactured by impregnating kraft paper with a phenolic resin solution, with a basis weight of 245 g / m². ２A core substrate consisting of three sheets of phenol resin-impregnated core paper (obtained by impregnating core craft paper with a liquid, uncured resin composition made of phenol resin) was laminated onto the core substrate, and then release films 1 to 9 were laminated onto the impregnated decorative sheet, respectively, to obtain nine types of laminates.

[0107] The resulting laminate is sandwiched between two mirrored plates and pressed using a hot press machine at a pressure of 100 kg / cm². ２ The uncured melamine resin composition was heat-molded at a molding temperature of 150°C for 25 minutes to form a cured resin layer containing melamine resin. This produced a cured laminate (resin-impregnated decorative panel including release film). The systems using release films 1 to 5 correspond to Examples 1 to 5, and the systems using release films 6 to 9 correspond to Comparative Examples 1 to 4.

[0108] (90° Tensile Test) The release film was peeled off the cured laminate (resin-impregnated decorative panel including the release film) obtained in Examples 1 to 5 and Comparative Examples 1 to 4 by a 90° tensile test. Figure 7(a) is a top view showing the test apparatus for the 90° tensile test in this disclosure, and Figure 7(b) is a cross-sectional view taken along line A-A in Figure 7(a). As shown in Figures 7(a) and (b), the test apparatus has a base, a floor placed on the base, a pair of walls extending from the floor, and four rollers fixed to the pair of walls. The dimensions of each component are as shown in Figures 7(a) and (b). As shown in Figure 7(c), the release film was pulled in a direction 90° with respect to the direction of travel of the resin-impregnated decorative panel, and the release film was peeled off the cured laminate (resin-impregnated decorative panel including the release film), and the integral mean load and the maximum point load were determined.

[0109] Specifically, a cured laminate (resin-impregnated decorative panel including a release film) was cut to a size of 25 mm in width and 150 mm in length to obtain a sample. Next, the release film and resin-impregnated decorative panel were peeled off from the edge of the sample to a position of approximately 30 mm (position A) and placed in the test apparatus. Then, the release film from which the resin-impregnated decorative panel had been peeled off was fixed and the release film was pulled at a speed of 100 mm / min in a direction 90° to the direction of travel of the resin-impregnated decorative panel, from position A to position B (75 mm). As shown in Figure 8, the integral average load (average of integral values) and the maximum point load were determined from position C (25 mm from position A) to position B. The results are shown in Tables 3 and 4.

[0110] (Releaseability of Release Film) The releaseability of the release film when peeling it off the cured laminate (resin-impregnated decorative panel including release film) obtained in Examples 1-5 and Comparative Examples 1-4 was evaluated using the following procedure. First, three samples were prepared by cutting the cured laminate (resin-impregnated decorative panel including release film) to a size of 25 mm in width and 150 mm in length. Next, the release film was pulled by hand from the end of the short side of the sample and slowly peeled off. At this time, if it was difficult to start peeling by hand alone due to strong adhesion, a sharp, thin jig such as a cutter blade or iron spatula was inserted between the release film and the resin-impregnated decorative panel to create a starting point, and then it was started to be pulled by hand to begin peeling. Also, if the release film broke during the peeling process, the jig described above was used to create a starting point at the broken part, and the peeling work of the release film was resumed. The release film was completely peeled off from the sample, and the number of times the release film broke was recorded. These operations were performed on all three samples, and the average number of release film ruptures was calculated to one decimal place.

[0111] The average number of release film ruptures was evaluated according to the following criteria. The results are shown in Tables 3 and 4. A: The average number of release film ruptures is 1.0 or less. B: The average number of release film ruptures is greater than 1.0 but 3.0 or less. C: The average number of release film ruptures is greater than 3.0, or there is one or more samples where the release film cannot be peeled off even with a jig, or where the design layer is taken off with the release film when peeling off the release film.

[0112] (Removability of the hardened resin layer) Three resin-impregnated decorative panels (resin-impregnated decorative panels after the release film has been removed) were prepared after the evaluation in "Releaseability of the release film" above. Next, the prepared resin-impregnated decorative panels were observed from the release layer side, and the hardened resin layer remaining on the release layer was visually confirmed. The removeability of the hardened resin layer in each sample was evaluated according to the following criteria: ○: The area covered by the hardened resin layer is 20% or less of the total area of ​​the release layer. △: The area covered by the hardened resin layer is more than 20% and 50% or less of the total area of ​​the release layer. ×: The area covered by the hardened resin layer is more than 50% of the total area of ​​the release layer, the release film cannot be peeled off even with a jig, or the design layer is taken off with the release film when the release film is peeled off.

[0113] Furthermore, the removeability of the hardened resin layer in the three resin-impregnated decorative panels was evaluated according to the following criteria: A: There are 0 "X" marks and 2 or more "O" marks among the three panels. B: There are 0 "X" marks and 1 or fewer "O" marks among the three panels. C: There is 1 or more "X" marks among the three panels.

[0114] (Contact angle of pure water of release film peeled from resin-impregnated decorative board) The contact angle of pure water of the first surface of the release film (release film peeled from resin-impregnated decorative board) after evaluation in "Releaseability of release film" above was measured by the following method. The release film was placed on a horizontal surface with the first surface facing upwards. Next, a water droplet (pure water, 2.0 μL) was dropped onto the first surface from a direction perpendicular to the horizontal plane. At this time, the water droplet was not dropped onto the cured resin layer present on the first surface, and the water droplet was dropped so that the entire water droplet was in contact with the first surface where there was no cured resin layer. After dropping the water droplet, a 10-second wait was made, and the contact angle between the first surface and the pure water was measured using a contact angle meter (fully automatic contact angle meter DMo-702, manufactured by Kyowa Interface Science Co., Ltd.). The above measurement was performed at 10 arbitrary locations, and the average value was taken as the pure water contact angle. The results are shown in Tables 3 and 4.

[0115]

[0116]

[0117] As shown in Table 3, in Examples 1 to 5, the release properties of the release film and the removal properties of the cured resin layer (melamine) on the release layer were good. In other words, it was confirmed that both the release properties of the release film and the removal properties of the cured resin layer (melamine) on the release layer could be achieved by setting the thickness of the release film and the pure water contact angle of the release film within a specific range. Furthermore, Examples 1 to 4 showed better release properties of the release film and the removal properties of the cured resin layer (melamine) on the release layer compared to Example 5. The reason for this is presumed to be that the melting point of the release film used in Examples 1 to 4 was higher than that of the release film used in Example 5, which prevented the release film from softening too much during hot pressing.

[0118] Furthermore, the melting point of the release film used in Example 5 (122°C) is lower than the molding temperature in the heat processing step (150°C), so melting of the release film occurred, and it is presumed that the release properties of the release film decreased (the release film became more prone to tearing) due to the melting of the release film. Therefore, it is presumed that the release properties of the release film in Example 5 were slightly inferior to those in Example 1. In addition, the release film used in Example 5 had a relatively larger pure water contact angle compared to the release film used in Example 1, resulting in relatively lower adhesion to the cured resin layer (melamine). Therefore, it is presumed that the removal of the cured resin layer (melamine) in Example 5 was slightly inferior to that in Example 1. Also, as shown in Examples 1 to 5, it was confirmed that the integral mean load in the 90° tensile test differed greatly depending on the release film.

[0119] As shown in Table 4, the release film did not peel well in Comparative Example 1. This is because the release film was thin and lacked sufficient mechanical strength, resulting in a large number of tearings during the peeling process. On the other hand, the cured resin layer was easily removed in Comparative Example 1. This is presumed to be because the release film could be peeled using a jig, and the adhesion between the release film and the cured resin layer was good due to the pure water contact angle being within a predetermined range.

[0120] As shown in Table 4, in Comparative Examples 2 and 3, the release film did not peel well, nor did the cured resin layer (melamine) on the release layer come off easily. This is presumed to be because the release films used in Comparative Examples 2 and 3 had too small a pure water contact angle. As a result of the excessively small pure water contact angle, the adhesion between the release film and the cured resin layer became excessively high, making it difficult to peel the release film from the cured resin layer.

[0121] As shown in Table 4, in Comparative Example 4, the release film exhibited good peelability, but the removal of the cured resin layer (melamine) on the release layer was not good. This is presumed to be because the pure water contact angle of the release film used in Comparative Example 4 was too large. As a result of the excessively large pure water contact angle, the adhesion between the release film and the cured resin layer became excessively low, making it difficult to selectively remove the cured resin layer (melamine) on the release layer.

[0122] Thus, the present disclosure provides, for example, the following inventions.

[0123] [1] A resin-impregnated decorative panel including a release film, having a core substrate, a decorative sheet, a cured resin layer, and a release film in this order in the thickness direction, wherein the decorative sheet has, in the thickness direction from the core substrate side, a porous substrate, a design layer, and a release layer having a pattern shape, wherein the decorative sheet and the cured resin layer contain a cured product of a curable resin Y, the release film has a thickness of 30 μm or more, the pure water contact angle on the surface of the release film facing the cured resin layer is 70.0° or more and 95.0° or less, and the release film contains a polyolefin resin or a polyester resin.

[0124] [2] A resin-impregnated decorative board containing the release film described in [1], wherein the thickness of the release film is 40 μm or more.

[0125] [3] A resin-impregnated decorative board containing the release film described in [1] or [2], wherein the thickness of the release film is 100 μm or less.

[0126] [4] A resin-impregnated decorative panel containing a release film according to any one of [1] to [3], wherein the pure water contact angle is 80.0° or more and 95.0° or less.

[0127] [5] A resin-impregnated decorative laminate containing the release film described in any of [1] to [4], wherein in a 90° tensile test in which the release film is peeled off from the resin-impregnated decorative laminate containing the release film, the integral mean load when the release film is pulled at a speed of 100 mm / min is 0.1 N or more and 4.0 N or less.

[0128] [6] A resin-impregnated decorative panel containing a release film according to any one of [1] to [5], wherein the thickness of the cured resin layer between the mold release layer and the release film is 30 μm or less.

[0129] [7] The release layer is a resin-impregnated decorative panel containing a release film according to any one of [1] to [6], the release layer containing a cured product of the curable resin X.

[0130] [8] A resin-impregnated decorative panel containing the release film described in [7], wherein the curable resin X is an ionizing radiation-curable resin.

[0131] [9] The resin-impregnated decorative laminate is a melamine decorative laminate, and is a resin-impregnated decorative laminate containing the release film described in any of [1] to [8].

[0132]

[10] A release film used in the manufacture of a resin-impregnated decorative board, having a core substrate, a decorative sheet, and a cured resin layer in this order in the thickness direction, wherein the decorative sheet has, in the thickness direction from the core substrate side, a porous substrate, a design layer, and a release layer having a pattern shape, wherein the decorative sheet and the cured resin layer contain a cured product of a curable resin Y, the cured resin layer is arranged between the patterns of the release layer, the release film has a thickness of 30 μm or more, the pure water contact angle on the side of the release film facing the cured resin layer is 70.0° or more and 95.0° or less, and the release film contains a polyolefin resin or a polyester resin.

[0133]

[11] A method for manufacturing a resin-impregnated decorative laminate, comprising: a preparation step of preparing a decorative sheet having a porous substrate, a design layer, and a release layer having a pattern shape in this order in the thickness direction; a laminate formation step of forming a laminate having (i) a core substrate, the decorative sheet, a curable resin layer containing a curable resin Y, and a release film in this order in the thickness direction, (ii) the surface of the decorative sheet facing the porous substrate, and (iii) the decorative sheet being impregnated with the curable resin Y; a heating and pressurizing step of heating and pressurizing the laminate to cure the curable resin Y and form a cured resin layer from the curable resin layer to obtain a cured laminate; a peeling step of peeling the release film from the cured laminate to remove the cured resin layer positioned in a position overlapping with the release layer in the thickness direction, while leaving the cured resin layer positioned between the patterns of the release layer, wherein the release film has a thickness of 30 μm or more. The pure water contact angle on the side of the release film facing the curable resin layer is 70.0° or more and 95.0° or less, and the release film contains a polyolefin resin or a polyester resin, in a method for manufacturing a resin-impregnated decorative panel.

[0134] 1…Porous substrate 2…Design layer 3…Release layer 10…Decorative sheet 20…Core substrate 30…Cured resin layer 40…Release film 100…Resin-impregnated decorative board

Claims

1. A resin-impregnated decorative panel including a release film, having a core substrate, a decorative sheet, a cured resin layer, and a release film in this order in the thickness direction, wherein the decorative sheet has, in the thickness direction from the core substrate side, a porous substrate, a design layer, and a release layer having a pattern shape, wherein the decorative sheet and the cured resin layer contain a cured product of a curable resin Y, the release film has a thickness of 30 μm or more, the pure water contact angle on the surface of the release film facing the cured resin layer is 70.0° or more and 95.0° or less, and the release film contains a polyolefin resin or a polyester resin.

2. The resin-impregnated decorative panel containing the release film according to claim 1, wherein the thickness of the release film is 40 μm or more.

3. The resin-impregnated decorative panel containing the release film according to claim 1, wherein the thickness of the release film is 100 μm or less.

4. The resin-impregnated decorative panel containing the release film according to claim 1, wherein the pure water contact angle is 80.0° or more and 95.0° or less.

5. The resin-impregnated decorative laminate containing the release film according to claim 1, wherein in a 90° tensile test in which the release film is peeled off from the resin-impregnated decorative laminate containing the release film, the integral mean load when the release film is pulled at a speed of 100 mm / min is 0.1 N or more and 4.0 N or less.

6. The resin-impregnated decorative panel containing the release film according to claim 1, wherein the thickness of the cured resin layer between the mold release layer and the release film is 30 μm or less.

7. A resin-impregnated decorative panel comprising the release film according to claim 1, wherein the release layer contains a cured product of the curable resin X.

8. The resin-impregnated decorative panel according to claim 7, wherein the curable resin X is an ionizing radiation-curable resin.

9. The resin-impregnated decorative laminate is a melamine decorative laminate, comprising the release film according to claim 1.

10. A release film used in the manufacture of a resin-impregnated decorative panel, having a core substrate, a decorative sheet, and a cured resin layer in this order in the thickness direction, wherein the decorative sheet has, in the thickness direction from the core substrate side, a porous substrate, a design layer, and a release layer having a pattern shape, wherein the decorative sheet and the cured resin layer contain a cured product of a curable resin Y, the cured resin layer is arranged between the patterns of the release layer, the release film has a thickness of 30 μm or more, the pure water contact angle on the surface of the release film facing the cured resin layer is 70.0° or more and 95.0° or less, and the release film contains a polyolefin resin or a polyester resin.

11. A method for manufacturing a resin-impregnated decorative laminate, comprising: a preparation step of preparing a decorative sheet having a porous substrate, a design layer, and a release layer having a pattern shape in this order in the thickness direction; a laminate formation step of forming a laminate having (i) a core substrate, the decorative sheet, a curable resin layer containing a curable resin Y, and a release film in this order in the thickness direction, (ii) the surface of the decorative sheet facing the porous substrate, and (iii) the decorative sheet being impregnated with the curable resin Y; a heating and pressurizing step of heating and pressurizing the laminate to cure the curable resin Y and form a cured resin layer from the curable resin layer to obtain a cured laminate; a peeling step of peeling the release film from the cured laminate to remove the cured resin layer positioned in a position overlapping with the release layer in the thickness direction, while leaving the cured resin layer positioned between the patterns of the release layer, wherein the release film has a thickness of 30 μm or more. A method for manufacturing a resin-impregnated decorative panel, wherein the pure water contact angle on the side of the release film facing the curable resin layer is 70.0° or more and 95.0° or less, and the release film contains a polyolefin resin or a polyester resin.

Images