JP7008277B2 - A peeling sheet and a method for manufacturing a decorative board using the peeling sheet. - Google Patents

Description

The present invention relates to a release sheet and a method for manufacturing a decorative board using the release sheet.

Conventionally, the surfaces of tables, counters, walls, floors, etc. are impregnated with a liquid resin composition containing an uncured melamine resin in a paper-like base material such as titanium paper, and a core such as phenol resin impregnated paper is used as necessary. A melamine decorative board manufactured by curing an uncured melamine resin by hot pressing after laminating on paper is used.

On the other hand, in order to express a high-class design, the surface of the decorative board is provided with an uneven shape. As such an uneven shape, a gloss matte uneven shape is known (for example, Patent Documents 1 and 2). The gloss matte uneven shape means an uneven shape in which a high gloss region and a low gloss region are mixed in a pattern on the surface of an article. On the surface of an article having a gloss matte uneven shape, the low-gloss region visually looks recessed as compared with the high-gloss region, regardless of the physical unevenness, thereby expressing a three-dimensional design feeling. ..

Patent Document 3 discloses a decorative board capable of expressing a gloss matte design and a method for manufacturing the decorative board. The decorative board described in Patent Document 3 includes a paper base material, a release layer provided on a part of the surface of the paper material base material, and the rest of the surface of the paper quality base material (the release layer of the surface of the paper quality base material). It is provided with a cured melamine resin layer provided in the region (area in which is not provided). The decorative board described in Patent Document 3 has a step of providing a release layer on a part of the surface of a paper-based substrate, a step of forming an uncured melamine resin layer covering the rest of the surface of the paper-based substrate and the release layer. A step of laminating a release sheet on an uncured melamine resin layer and then heating to cure the uncured melamine resin layer to form a cured melamine resin layer, and a step of peeling the release sheet to cure a cured melamine resin. It is manufactured by a method including a step of peeling off a portion of the layer that covers the release layer.

Special Publication No. 49-39166 Special Fair 1-20065 Gazette International Publication No. 2016/148091

In Patent Document 3, the bonding strength between the release sheet and the cured melamine resin layer is larger than the bonding strength between the release target portion (the portion of the cured melamine resin layer that covers the release layer) and the release layer, and the cured melamine. The strength is smaller than the bonding strength between the remaining part of the resin layer (the part of the cured melamine resin layer that does not cover the release layer) and the paper substrate, and is smaller than the bonding strength between the release layer and the paper substrate. Be adjusted. However, if the bonding strength between the release sheet and the cured melamine resin layer is not sufficiently high, the release target portion may not be sufficiently peeled and a part of the release target portion may remain on the release layer. In particular, in the case of mass production of decorative boards, the heat pressing conditions at the time of manufacture, the composition of the melamine resin composition used for forming the cured melamine resin layer, etc., vary to the extent normally expected, and therefore, when the release sheet is peeled off. There is a risk that the part to be peeled off will not be peeled off in a stable manner with good reproducibility.

Therefore, the present invention uses a release sheet and the release sheet that can be bonded to the cured melamine resin layer with a bonding strength suitable for peeling the release target portion (the portion of the cured melamine resin layer that covers the release layer). It is an object of the present invention to provide a method for manufacturing a plastic plate.

In order to solve the above problems, the present invention provides the following inventions.
[1] A release sheet having a first surface and a second surface located on the opposite side of the first surface.
The release sheet comprises a base material sheet and a surface layer forming the first surface of the release sheet.
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.
The release sheet in which 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 with respect to 100 parts by mass of the ionizing radiation curable resin.
[2] The ionizing radiation curable resin composition contains a polyfunctional monomer of 80% by mass or more and 97% by mass or less based on the total solid content of the ionizing radiation curable resin composition in [1]. The peeling sheet described.
[3] The release sheet according to [1] or [2], further comprising a primer layer provided between the base material sheet and the surface layer.
[4] A method for manufacturing a decorative board using the release sheet according to any one of [1] to [3].
(1) A support layer having a first surface and a second surface located on the opposite side of the first surface, a mold release layer provided on a part of the first surface of the support layer, and a first of the support layers. The uncured melamine resin layer covering the rest of one surface and the release layer, and the uncured melamine resin layer provided on the uncured melamine resin layer so that the first surface of the release sheet is in contact with the uncured melamine resin layer. A step of preparing a laminate including a release sheet and a precursor layer of a core layer provided on the second surface of the support layer.
(2) A step of curing the uncured melamine resin layer by pressurizing and heating the laminate to form a cured melamine resin layer, and
(3) By peeling off the release sheet, the portion of the cured melamine resin layer that covers the release layer is peeled off, and the cured melamine resin layer is provided with an opening that exposes the surface of the release layer. The method comprising the step of forming.
[5] The method according to [4], wherein the support layer has a paper-like substrate.
[6] The method according to [5], wherein the support layer further has a decorative layer provided on the paper-based substrate.
[7] The laminate prepared in the step (1) contains an uncured product of a melamine resin filled in the voids of the paper substrate.
In the step (2), the laminated body is pressurized and heated to cure the uncured melamine resin filled in the voids of the paper substrate together with the uncured melamine resin layer, and the paper substrate is cured. The method according to [5] or [6], wherein the cured product of the melamine resin filled in the voids of the above and the cured product of the melamine resin contained in the cured melamine resin layer are integrated.

According to the present invention, a release sheet and the release sheet that can be bonded to the cured melamine resin layer with a bonding strength suitable for peeling the release target portion (the portion of the cured melamine resin layer that covers the release layer) are used. It is an object of the present invention to provide a method for manufacturing a plastic plate.

FIG. 1 is a cross-sectional view schematically showing the structure of a release sheet according to an embodiment of the present invention. FIG. 2 is a plan view of a decorative board according to an embodiment of the present invention. FIG. 3 is an enlarged view of a region represented by reference numeral R in FIG. FIG. 4 is a cross-sectional view taken along the line AA of FIG. FIG. 5 is a cross-sectional view taken along the line BB of FIG. FIG. 6 is an explanatory diagram for explaining a method for manufacturing a decorative board according to an embodiment of the present invention. FIG. 7 is an explanatory diagram (continuation of FIG. 6) for explaining a method for manufacturing a decorative board according to an embodiment of the present invention. FIG. 8 is an explanatory diagram for explaining a method of measuring the peeling weight.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

≪Structure of release sheet≫
Hereinafter, the configuration of the release sheet 10 according to the embodiment of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view schematically showing the structure of the release sheet 10.

As shown in FIG. 1, the release sheet 10 has a first surface S10 and a second surface T10 located on the opposite side of the first surface S10.

As shown in FIG. 1, the release sheet 10 is a primer provided between the base sheet 11, the surface layer 12 forming the first surface S10 of the release sheet 10, and the base sheet 11 and the surface layer 12. A layer 13 is provided. The primer layer 13 is a layer provided as needed, and the present invention also includes an embodiment in which the primer layer 13 is omitted.

Base sheet The base sheet 11 is not particularly limited as long as it can support the layer provided on the surface thereof. The base sheet 11 preferably has flexibility, and more preferably heat resistance and dimensional stability in addition to flexibility. As the base material sheet 11, for example, a plastic sheet is used. Examples of the synthetic resin constituting the plastic sheet include polyolefin resins such as polyethylene resin, polypropylene resin, polymethylpentene resin, and olefin-based thermoplastic elastomer; polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl alcohol resin, vinyl chloride- Vinyl-based resins such as vinyl acetate copolymer resin, ethylene-vinyl acetate copolymer resin, ethylene-vinyl alcohol copolymer resin; polyethylene terephthalate resin, polybutylene terephthalate resin, ethylene naphthalate-isophthalate copolymer resin, polyester-based thermoplastic Polyester resin such as elastomer; Acrylic resin such as poly (meth) methyl acrylate resin, poly (meth) ethyl acrylate resin, poly (meth) butyl acrylate resin; polyamide resin typified by nylon 6 or nylon 66; Examples thereof include cellulose-based resins such as cellulose acetate resin and cellophane; polystyrene resin; polycarbonate resin; polyallylate resin; polyimide resin and the like. Of these, polyester resins such as polyethylene terephthalate, particularly biaxially stretched polyester resins, are preferable from the viewpoint of excellent heat resistance and dimensional stability.

In order to improve the adhesion to the layer provided on the surface of the base sheet 11, the surface of the base sheet 11 may be subjected to physical or chemical surface treatment such as an oxidation method or an unevenness method. Examples of the oxidation method include corona discharge treatment, chromium oxidation treatment, flame treatment, hot air treatment, ozone / ultraviolet treatment method and the like, and examples of the unevenness method include sandblasting method and solvent treatment method.

An easy-adhesive layer may be formed on the surface of the base sheet 11 in order to improve the adhesion to the layer provided on the surface of the base sheet 11. Examples of the easy-adhesive resin contained in the easy-adhesion layer (sometimes called a primer layer or an anchor layer) include acrylic resin, vinyl chloride-vinyl acetate copolymer, polyester resin, urethane resin, chlorinated polypropylene, and chlorine. Examples include polyethylene chemicals.

The thickness of the base sheet 11 can be appropriately adjusted, but when the plastic sheet is used as the base sheet 11, the thickness of the plastic sheet is preferably 25 μm or more and 100 μm or less, and more preferably 38 μm or more and 50 μm or less. be.

Surface layer As shown in FIG. 1, the surface layer 12 is provided on the first surface S10 side of the base sheet 11, and forms the first surface S10 of the release sheet 10. The surface layer 12 may form a part of the first surface S10 of the release sheet 10, but it is preferable that the surface layer 12 forms the entire first surface S10 of the release sheet 10. The surface layer 12 may be composed of one continuous layer or may be composed of a plurality of discontinuous layers.

The thickness of the surface layer 12 can be appropriately adjusted, but is preferably 1 μm or more and 5 μm or less, and more preferably 2 μm or more and 4 μm or less. When the thickness of the surface layer 12 is not uniform, it is preferable that both the minimum thickness and the maximum thickness of the surface layer 12 are within the above range.

The surface layer 12 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. Therefore, the surface layer 12 contains a cured product of an ionizing radiation curable resin and a silane coupling agent having an amino group. The silane coupling agent having an amino group may be present in the surface layer 12 in the form of its hydrolyzate or a polycondensate of the hydrolyzate. The silane coupling agent having an amino group, its hydrolyzate, or the polycondensate of the hydrolyzate may be present in the surface layer 12 in a state of being bound to the cured product of the ionizing radiation curable resin.

The ionizing radiation curable resin contained in the ionizing radiation curable resin composition used for forming the surface layer 12 may be one kind or two or more kinds. The silane coupling agent having an amino group contained in the ionizing radiation curable resin composition used for forming the surface layer 12 may be one kind or two or more kinds.

The amount of the ionizing radiation curable resin contained in the ionizing radiation curable resin composition used for forming the surface layer 12 is usually 70% by mass or more based on the total solid content mass of the ionizing radiation curable resin composition 97. It is mass% or less, preferably 75% by mass or more and 97% by mass or less, and more preferably 80% by mass or more and 97% by mass or less. When the ionizing radiation curable resin composition contains two or more types of ionizing radiation curable resins, the amount of the ionizing radiation curable resin means the total amount of the two or more types of ionizing radiation curable resins.

The amount of the silane coupling agent having an amino group contained in the ionizing radiation curable resin composition used for forming the surface layer 12 is 100 parts by mass of the ionizing radiation curable resin contained in the ionizing radiation curable resin composition. On the other hand, it is 3 parts by mass or more and 9 parts by mass or less, preferably 4 parts by mass or more and 8 parts by mass or less, and more preferably 5 parts by mass or more and 7 parts by mass or less. When the silane coupling agent having an amino group contained in the ionizing radiation curable resin composition is two or more kinds, the amount of the silane coupling agent having an amino group is the amount of the silane coupling agent having two or more kinds having an amino group. Means the total amount of.

Ionizing Radiation Curable Resin Compositions The following description of ionizing radiation curable resin compositions is not limited to the ionizing radiation curable resin compositions used to form the surface layer 12 as well as the surfaces, unless otherwise specified. It is also applied to an ionizing radiation curable resin composition used for forming a layer other than the layer 12.

The ionizing radiation curable resin composition contains one or more ionizing radiation curable resins. The ionizing radiation curable resin is a resin that undergoes a cross-linking polymerization reaction by irradiation with ionizing radiation and changes into a three-dimensional polymer structure. Ionizing radiation means an electromagnetic wave or a charged particle beam that has an energy quantum capable of polymerizing or cross-linking a molecule, and usually ultraviolet (UV) or electron beam (EB) is used, but in addition, X It also includes electromagnetic waves such as rays and γ-rays, and charged particle beams such as α-rays and ion rays. Among the ionizing radiation curable resins, the electron beam curable resin is preferable in that it can be made solvent-free and stable curing characteristics can be obtained.

As the ionizing radiation curable resin, for example, one or more of a monomer, an oligomer, a prepolymer, etc. having a polymerizable unsaturated bond, a cationically polymerizable functional group, etc. in the molecule, which can be crosslinked by irradiation with ionizing radiation, shall be used. Can be done.

Examples of the monomer used as the ionizing radiation curable resin include (meth) acrylate monomers having a radically polymerizable unsaturated group in the molecule, and polyfunctional (meth) acrylate monomers are particularly preferable. In addition, "(meth) acrylate" means acrylate or methacrylate.

The polyfunctional (meth) acrylate monomer may be any (meth) acrylate monomer having two or more (bifunctional or higher), preferably three or more (trifunctional or higher) polymerizable unsaturated bonds in the molecule. Not limited. Examples of the polyfunctional (meth) acrylate include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, and 1,6-hexanediol di (meth). Acrylate, Neopentyl glycol di (meth) acrylate, Polyethylene glycol di (meth) acrylate, Neopentyl glycol di (meth) acrylate hydroxypivalate, Dicyclopentanyldi (meth) acrylate, Caprolactone-modified dicyclopentenyldi (meth) Acrylate, ethylene oxide-modified di (meth) acrylate, allylated cyclohexyl di (meth) acrylate, isocyanurate di (meth) acrylate, trimethyl propanetri (meth) acrylate, ethylene oxide-modified trimethyl propanetri (meth) acrylate, di Pentaerythritol tri (meth) acrylate, propionic acid-modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide-modified trimethylolpropanetri (meth) acrylate, tris (acryloxyethyl) isocyanurate, propion Examples thereof include acid-modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ethylene oxide-modified dipentaerythritol hexa (meth) acrylate, and caprolactone-modified dipentaerythritol hexa (meth) acrylate. The polyfunctional (meth) acrylate may be used alone or in combination of two or more. A monofunctional (meth) acrylate may be used in combination with the polyfunctional (meth) acrylate for the purpose of lowering the viscosity thereof.

Examples of the oligomer used as the ionizing radiation curable resin include (meth) acrylate oligomers having a radically polymerizable unsaturated group in the molecule, and in particular, two polymerizable unsaturated bonds in the molecule. A polyfunctional (meth) acrylate oligomer having the above (bifunctional or higher) is preferable. Examples of the polyfunctional (meth) acrylate oligomer include polycarbonate (meth) acrylate, acrylic silicone (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, and polyether (meth) acrylate. , Polybutadiene (meth) acrylate, silicon (meth) acrylate, oligomers having a cationically polymerizable functional group in the molecule (for example, novolak type epoxy resin, bisphenol type epoxy resin, aliphatic vinyl ether, aromatic vinyl ether, etc.) and the like. .. Here, the polycarbonate (meth) acrylate is not particularly limited as long as it has a carbonate bond in the polymer main chain and has a (meth) acrylate group in the terminal or side chain, and for example, a polycarbonate polyol (meth) is used. It can be obtained by esterification with acrylic acid. The polycarbonate (meth) acrylate may be, for example, urethane (meth) acrylate having a polycarbonate skeleton or the like. Urethane (meth) acrylate having a polycarbonate skeleton can be obtained, for example, by reacting a polycarbonate polyol with a polyhydric isocyanate compound and a hydroxy (meth) acrylate. Acrylic silicone (meth) acrylate can be obtained by radically copolymerizing a silicone macromonomer with a (meth) acrylate monomer. Urethane (meth) acrylate can be obtained, for example, by esterifying a polyurethane oligomer obtained by a reaction between a polyether polyol or a polyester polyol and a polyisocyanate with (meth) acrylic acid. Epoxy (meth) acrylate can be obtained, for example, by reacting (meth) acrylic acid with an oxylan ring of a relatively low molecular weight bisphenol type epoxy resin or a novolak type epoxy resin to esterify it. Further, a carboxyl-modified epoxy (meth) acrylate obtained by partially modifying this epoxy (meth) acrylate with a dibasic carboxylic acid anhydride can also be used. The polyester (meth) acrylate can be obtained, for example, by esterifying the hydroxyl group of a polyester oligomer having hydroxyl groups at both ends obtained by condensation of a polyvalent carboxylic acid and a polyhydric alcohol with (meth) acrylic acid, or to a polyvalent carboxylic acid. It can be obtained by esterifying the hydroxyl group at the end of the oligomer obtained by adding an alkylene oxide with (meth) acrylic acid. The polyether (meth) acrylate can be obtained by esterifying the hydroxyl group of the polyether polyol with (meth) acrylic acid. Polybutadiene (meth) acrylate can be obtained by adding (meth) acrylic acid to the side chain of the polybutadiene oligomer. Silicon (meth) acrylate can be obtained by adding (meth) (meth) acrylic acid to the terminal or side chain of silicon having a polysiloxane bond in the main chain. Among these, urethane (meth) acrylate oligomers are preferable from the viewpoint of further increasing the hardness of the cured product of the ionizing radiation curable resin composition. These oligomers may be used alone or in combination of two or more.

The weight average molecular weight of the ionizing radiation curable resin is preferably 500 or more, more preferably 1000 or more. When the weight average molecular weight of the ionizing radiation curable resin is in the above range, it is easy to form a coating film of the ionizing radiation curable resin composition when the ionizing radiation curable resin composition is applied.

The weight average molecular weight of the ionizing radiation curable resin is preferably 80,000 or less, more preferably 50,000 or less. When the weight average molecular weight of the ionizing radiation curable resin is in the above range, it is easy to adjust the viscosity of the ionizing radiation curable resin composition to a viscosity suitable for coating.

The "weight average molecular weight" is a value measured by gel permeation chromatography (GPC) using polystyrene as a standard substance.

The ionizing radiation curable resin is preferably at least one selected from polyfunctional monomers and oligomers having a weight average molecular weight of 500 or more. Examples of such a polyfunctional monomer or oligomer include acrylate resins such as dipentaerythritol hexaacrylate, dipentaerythritol pentaacrylate, urethane acrylate, polyester acrylate, and epoxy acrylate.

If necessary, the ionizing radiation curable resin composition may contain a component involved in the curing reaction of the ionizing radiation curable resin, for example, a photopolymerization initiator (sensitizer). For example, when the ionizing radiation curable resin is cured by irradiation with ultraviolet rays, the ionizing radiation curable resin composition preferably contains a photopolymerization initiator (sensitizer). Since the ionizing radiation curable resin is sufficiently cured by irradiating it with an electron beam, when the ionizing radiation curable resin is cured by irradiating it with an electron beam, the ionizing radiation curable resin composition is a photopolymerization initiator (sensitization). Agent) may not be included.

When the ionizing radiation curable resin has a radically polymerizable unsaturated group, the photopolymerization initiator may be, for example, acetophenones, benzophenones, thioxanthones, benzoins, benzoin methyl ethers, Michler benzoyl benzoates, Michler ketones, diphenyl sulfides, etc. At least one of dibenzyldisulfide, diethyloxide, triphenylbiimidazole, isopropyl-N, N-dimethylaminobenzoate and the like can be used. When the ionizing radiation curable resin has a cationically polymerizable functional group, the photopolymerization initiator may be, for example, an aromatic diazonium salt, an aromatic sulfonium salt, a metallocene compound, a benzoin sulfonic acid ester, or a freele oxysulfoxonium. At least one kind such as diallyl iodosyl salt can be used.

The amount of the photopolymerization initiator contained in the ionizing radiation curable resin composition is not particularly limited, but is usually 0.1 part by mass with respect to 100 parts by mass of the ionizing radiation curable resin contained in the ionizing radiation curable resin composition. It is 10 parts by mass or less.

The ionizing radiation curable resin composition is a solvent-drying resin (a resin such as a thermoplastic resin that can be formed into a film simply by drying a solvent added to adjust the solid content at the time of coating), if necessary. , Thermosetting resin and the like may be contained. By adding the solvent-drying resin to the ionizing radiation curable resin composition, it is possible to effectively prevent film defects on the coated surface of the ionizing radiation curable resin composition. As the solvent-drying resin, for example, a thermoplastic resin can be used, and as the thermoplastic resin, for example, a styrene resin, a (meth) acrylic resin, a vinyl acetate resin, a vinyl ether resin, and a halogen-containing resin can be used. , Alicyclic olefin resin, polycarbonate resin, polyester resin, polyamide resin, cellulose derivative, silicone resin and rubber or elastomer. Examples of the thermosetting resin include phenol resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, polyurethane resin, epoxy resin, aminoalkyd resin, melamine-urea cocondensation resin, and silicon resin. Examples thereof include polysiloxane resin.

The ionizing radiation curable resin composition preferably contains a polyfunctional monomer. When the ionizing radiation curable resin composition contains a polyfunctional monomer, the hardness of the cured product of the ionizing radiation curable resin composition can be improved. The hardness of the cured product of the ionizing radiation curable resin composition can be adjusted to a desired range by adjusting the functional number, amount and the like of the polyfunctional monomer contained in the ionizing radiation curable resin composition. The amount of the polyfunctional monomer contained in the ionizing radiation curable resin composition is usually 70 parts by mass or more and 97 parts by mass or less, preferably 75 parts by mass or more, based on the total solid content mass of the ionizing radiation curable resin composition. It is 97 parts by mass or less, more preferably 80 parts by mass or more and 97 parts by mass or less. The polyfunctional monomer is not particularly limited as long as it has two or more polymerizable unsaturated groups or cationically polymerizable functional groups, but a trifunctional or higher functional monomer is preferable. Examples of the polyfunctional monomer include the above-mentioned polyfunctional (meth) acrylate monomer and the like.

Silane coupling agent There are two types of silane coupling agent: a reactive group that chemically bonds to an inorganic material as a hydroxyl group by hydrolysis (hydrolytic group) and a reactive group that chemically bonds to an organic material (reactive functional group). It is an organic silicon compound having the above different reactive groups.

A silane coupling agent having an amino group has an amino group as a reactive functional group. The silane coupling agent having an amino group may be a silane coupling agent having a primary amino group or a silane coupling agent having a secondary amino group, but may be a primary amino. It is preferably a silane coupling agent having a group. The silane coupling agent having a primary amino group may have a secondary amino group in addition to the primary amino group.

Examples of the silane coupling agent having an amino group include a silane coupling agent represented by the following formula A or formula B.

Formula A: R ⁵ HN-R ¹ -Si (-R ³ ) _n (-R ⁴ ) _3-n
Formula B: R ⁵ HN-R ¹ -NH-R ² -Si (-R ³ ) _n (-R ⁴ ) _3-n

In formulas A and B, R ¹ and R ² each independently represent a linear or branched alkylene group having 1 to 6 carbon atoms (preferably 1 to 4 carbon atoms), and R ³ is Each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms (preferably 1 to 4 carbon atoms) or a cycloalkyl group having 3 to 8 carbon atoms, and R ⁴ is independent of each other. Represents a linear or branched alkoxy group having 1 to 6 carbon atoms (preferably 1 to ⁴ carbon atoms), and R5 independently has a hydrogen atom and 1 to 6 carbon atoms (preferably 1 to 6 carbon atoms). Represents a linear or branched alkyl group having 1 to 4) carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms or an aralkyl group having 7 to 10 carbon atoms, where n is. Represents an integer from 0 to 2.

Examples of the alkylene group represented by R ¹ or R ² include a methylene group, an ethylene group, a propylene group, a butylene group and the like.

Examples of the alkyl group represented by R ³ include a methyl group, an ethyl group, a propyl group, a butyl group and the like.

Examples of the cycloalkyl group represented by R ³ include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl and the like.

Examples of the alkoxy group represented by ^R4 include a methoxy group, an ethoxy group, a propoxy group, a butoxy group and the like. The alkoxy group represented by ^R4 is preferably a methoxy group or an ethoxy group.

Examples of the alkyl group represented by R ⁵ include a methyl group, an ethyl group, a propyl group, a butyl group and the like.

Examples of the cycloalkyl group represented by R ⁵ include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl and the like.

Examples of the aryl group represented by R ⁵ include a phenyl group, a tolyl group, a xylyl group and the like.

Examples of the aralkyl group represented by ^R5 include a benzyl group, a phenethyl group, a naphthylmethyl group, a naphthylethyl group and the like.

If the silane coupling agent has a primary amino group, ^R5 is a hydrogen atom.

Examples of the silane coupling agent having an amino group include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, and N-2-. (Aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltriethoxysilane, 3- (N-phenyl) aminopropyltrimethoxysilane, N- (vinylbenzyl)- Examples thereof include 2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride. The silane coupling agent having an amino group is preferably 3-aminopropyltrimethoxysilane or 3-aminopropyltriethoxysilane.

The ionizing radiation curable resin composition used for forming the silica particle surface layer 12 may contain silica particles, if necessary. The silica particles can be appropriately selected from those used as a matting agent. The average particle size of the silica particles is preferably 1 μm or more and 10 μm or less, and more preferably 3 μm or more and 7 μm or less. The average particle size is measured on a volume basis by a laser diffraction / scattering method according to JIS Z8825: 2013. As a commercially available device for measuring a volume-based particle size distribution by a laser diffraction / scattering method, for example, a particle size distribution measuring device LS-230 manufactured by Beckman Coulter can be mentioned. Examples of silica particles include Aerosil-200, 200V, 300, R972, R972V, R974, R976, R976S, R202, R812, R805, OX50, TT600, RY50, RX50, NY50, NAX50, NA50H manufactured by Nippon Aerosil Co., Ltd. , NA50Y, NX90, RY200S, RY200, RX200, R8200, RA200H, RA200HS, NA200Y, R816, R104, RY300, RX300, R106 and the like. The silica particles contained in the ionizing radiation curable resin composition used for forming the surface layer 12 may be one kind or two or more kinds. The amount of silica particles contained in the ionizing radiation curable resin composition used for forming the surface layer 12 is preferably 30 with respect to 100 parts by mass of the ionizing radiation curable resin contained in the ionizing radiation curable resin composition. It is not more than parts by mass, more preferably 20 parts by mass or less. The lower limit of the amount of silica particles contained in the ionizing radiation curable resin composition is not particularly limited, but the amount of silica contained in the ionizing radiation curable resin composition is preferably 5 parts by mass or more, more preferably 10 parts by mass. It is more than a part.

Primer layer As shown in FIG. 1, the primer layer 13 is provided between the base sheet 11 and the surface layer 12. In the present embodiment, the primer layer 13 is formed on the entire surface of the base sheet 11 on the first surface S10 side, but even if it is formed on a part of the surface of the base sheet 11 on the first surface S10 side. good. In the present embodiment, the primer layer 13 is provided on the surface of the base sheet 11 on the first surface S10 side, but one or more layers are provided between the base sheet 11 and the primer layer 13. May be. In the present embodiment, the surface layer 12 is provided on the surface on the first surface S10 side of the primer layer 13, but one or more layers are provided between the surface layer 12 and the primer layer 13. May be good. Such a layer can be appropriately selected according to the function required for the layer.

The primer layer 13 contains a binder resin. Examples of the binder resin include urethane resin, (meth) acrylic resin, (meth) acrylic-urethane copolymer resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-acrylic copolymer resin, and chlorine. Examples thereof include synthetic polypropylene resin, polyester resin, polyamide resin, butyral resin, polystyrene resin, nitrocellulose resin (nitrated cotton), cellulose acetate resin and the like. As the binder resin, one kind may be used alone, or two or more kinds may be used in combination.

The primer layer 13 may contain one or more additives such as a stabilizer, a lubricant, an antioxidant, an antistatic agent, an antifoaming agent, and an optical brightener, if necessary.

The thickness of the primer layer 13 can be appropriately adjusted, but is preferably 1 μm or more and 5 μm or less, and more preferably 2 μm or more and 4 μm or less.

≪Manufacturing of release sheet≫
Hereinafter, an embodiment of a method for manufacturing the release sheet 10 will be described.
First, the primer layer 13 is formed on the surface of the base sheet 11 on the first surface S10 side. Even if the surface on the first surface S10 side of the base sheet 11 is subjected to physical or chemical surface treatment such as formation of an easy-adhesion layer or an oxidation method or an unevenness method before forming the primer layer 13. good. This makes it possible to improve the adhesion between the base sheet 11 and the surface layer 12.

The primer layer 13 can be formed by applying a primer layer forming composition to the surface on the first surface S10 side of the base sheet 11. Examples of the method for applying the primer layer forming composition include a spin coating method, a dip method, a spray method, a slide coating method, a bar coating method, a roll coating method, a gravure coating method, and a die coating method.

The composition for forming a primer layer is, for example, a mixture of a solvent or a dispersion medium and a solid content such as a binder resin. Examples of the solvent or dispersion medium include petroleum-based organic solvents such as hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane, and methylcyclohexane; ethyl acetate, butyl acetate, -2-methoxyethyl acetate, and -2-ethoxy acetate. Ether-based organic solvent such as ethyl; Alcohol-based organic solvent such as methyl alcohol, ethyl alcohol, normal propyl alcohol, isopropyl alcohol, isobutyl alcohol, ethylene glycol, propylene glycol; Ketone-based organic solvent such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc. Solvents; ether-based organic solvents such as diethyl ether, dioxane, tetrahydrofuran; chlorine-based organic solvents such as dichloromethane, carbon tetrachloride, trichloroethylene, tetrachloroethylene; inorganic solvents such as water and the like can be mentioned. As the solvent or the dispersion medium, one type may be used alone, or two or more types may be used in combination.

The coating amount of the primer layer forming composition can be appropriately adjusted, but is preferably 1 g / m ² or more and 5 g / m ² or less, and more preferably 2 g / m ² or more and 4 g / m ² or less.

After the formation of the primer layer 13, the ionizing radiation curable resin composition (composition for forming the surface layer) used for forming the surface layer 12 is applied onto the primer layer 13. Specific examples of the method for applying the surface layer forming composition are the same as described above.

The surface layer forming composition is, for example, a mixture of a solvent or a dispersion medium and a solid content such as an ionizing radiation curable resin and a silane coupling agent having an amino group. Specific examples of the solvent or the dispersion medium are the same as described above. As the solvent or the dispersion medium, one type may be used alone, or two or more types may be used in combination. The surface layer forming composition may contain a thermoplastic resin, a thermosetting resin, a photopolymerization initiator and the like, if necessary. Further, the composition for forming a surface layer includes a dispersant, a surfactant, an antistatic agent, a silane coupling agent having no amino group, and an increase for the purpose of increasing the hardness of the surface layer and suppressing curing shrinkage. Adhesives, color inhibitors, colorants (pigments, dyes), defoamers, leveling agents, flame retardants, UV absorbers, adhesives, polymerization inhibitors, antioxidants, surface modifiers, slippery agents, etc. It may be included.

The coating amount of the surface layer forming composition can be appropriately adjusted, but is preferably 1 g / m ² or more and 5 g / m ² or less, and more preferably 2 g / m ² or more and 4 g / m ² or less.

After the coating film of the surface layer forming composition formed on the primer layer 13 is dried, the coating film of the surface layer forming composition is cured by irradiating it with ionizing radiation such as ultraviolet rays and electron beams to cure the surface layer. 12 is formed.

When ultraviolet rays are used as ionizing radiation, a light source such as an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc lamp, a black light fluorescent lamp, or a metal halide lamp can be used as the ultraviolet source. The wavelength of ultraviolet rays is usually 190 nm or more and 380 nm or less. When an electron beam is used as ionizing radiation, the electron beam source may be, for example, an electron such as a Cockcroft-Walth type, a Van de Graaff type, a resonance transformer type, an insulated core transformer type, a linear type, a dynamitron type, or a high frequency type. A line accelerator can be used. The energy of the electron beam is usually 100 keV or more and 1000 keV or less, preferably 100 keV or more and 300 keV or less. The irradiation amount of the electron beam is usually 2 Mrad or more and 15 Mrad or less.

≪Use of release sheet≫
The release sheet 10 is used for manufacturing a decorative board having recesses on the surface. Hereinafter, an embodiment of a method of manufacturing a decorative board using the release sheet 10 will be described with reference to the drawings.

<Decorative board>
Hereinafter, the decorative board 20 which is the result of the manufacturing method according to the present embodiment will be described with reference to the drawings. 2 is a plan view of the decorative board 20, FIG. 3 is an enlarged view of a region indicated by reference numeral R in FIG. 2, and FIG. 4 is a sectional view taken along line AA of FIG. 5 is a cross-sectional view taken along the line BB of FIG.

As shown in FIGS. 2 to 5, the decorative board 20 has a first direction X, a second direction Y, and a thickness direction Z orthogonal to each other. In the present embodiment, the first direction X corresponds to the longitudinal direction of the decorative plate 20, the second direction Y corresponds to the lateral direction of the decorative plate 20, but the first direction X corresponds to the lateral direction of the decorative plate 20. The second direction Y may correspond to the longitudinal direction of the decorative plate 20.

As shown in FIGS. 2 to 5, the decorative plate 20 has a first surface S20 and a second surface T20 located on the opposite side of the first surface S20.

As shown in FIGS. 4 and 5, the decorative plate 20 has a support layer 21 having a second surface T21 located on the opposite side of the first surface S21 and the first surface S21, and the first surface S21 of the support layer 21. The release layer 22 provided in a part thereof, the cured melamine resin layer 23 provided in the rest of the first surface S21 of the support layer 21, and the core layer 24 provided in the second surface T21 of the support layer 21 are provided. Be prepared.

Support layer As shown in FIGS. 4 and 5, the first surface S21 of the support layer 21 is located on the first surface S20 side of the decorative plate 20, and the second surface T21 of the support layer 21 is the second surface T21 of the decorative plate 20. It is located on the two-sided T20 side.

As shown in FIGS. 4 and 5, the support layer 21 includes a paper-based base material 211 and a decorative layer 212 provided on the first surface S21 side of the paper-based base material 211.

Paper- based base material The paper-based base material 211 can be appropriately selected from the base papers generally used in the field of decorative boards or decorative papers. Examples of the paper base material 211 include titanium paper, thin leaf paper, kraft paper, coated paper, art paper, sulfate paper, glassin paper, parchment paper, paraffin paper, Japanese paper and the like.

The basis weight of the paper substrate 211 can be appropriately adjusted, but is preferably 30 g / m ² or more and 200 g / m ² or less, and more preferably 40 g / m ² or more and 150 g / m ² or less.

The thickness of the paper substrate 211 can be appropriately adjusted, but is preferably 30 μm or more and 200 μm or less, and more preferably 50 μm or more and 170 μm or less.

The paper substrate 211 preferably contains an inorganic component. The inorganic component contained in the paper substrate 211 may be one kind or two or more kinds. The paper base material 211 containing an inorganic component can be produced, for example, by blending an inorganic component with a raw material of paper and making the inorganic component into paper in a papermaking process.

The inorganic component can be appropriately selected from the inorganic components generally used in the field of decorative boards or decorative papers. Examples of the inorganic component include an inorganic filler (inorganic filler), an inorganic pigment, and the like.

Examples of the inorganic filler include titanium oxide, calcium oxide, magnesium oxide, zinc oxide, calcium carbonate, magnesium carbonate, silica, kaolin, clay, barium sulfate, calcium hydroxide, aluminum hydroxide, alumina, magnesium hydroxide, and talc. , Mica, hydrotalcite, aluminum silicate, magnesium silicate, calcium silicate, calcined talc, wollastonite, potassium titanate, magnesium sulfate, calcium sulfate, magnesium phosphate and the like.

Examples of inorganic pigments include titanium oxide, zinc flower, carbon black, black iron oxide, yellow iron oxide, yellow lead, molybdate orange, cadmium yellow, nickel titanium yellow, iron oxide (valve handle), cadmium red, and ultramarine. Navy blue, cobalt blue, chromium oxide, cobalt green, aluminum powder, bronze powder, mica titanium, zinc sulfide and the like can be mentioned.

The inorganic component is, for example, inorganic particles. The average particle size of the inorganic particles is not particularly limited, but is preferably 0.1 μm or more and 50 μm or less, and more preferably 0.1 μm or more and 10 μm or less. The average particle size means the median diameter of the volume-based particle size distribution measured by the laser diffraction / scattering method.

The inorganic component is preferably titanium oxide. Paper containing titanium oxide is called titanium paper. Increasing the amount of titanium oxide contained in the paper substrate 211 can improve the permeability of the uncured melamine resin composition and the ionizing radiation curable resin composition to the paper substrate 211.

The amount of the inorganic component contained in the paper substrate 211 can be appropriately adjusted according to the type of the inorganic component and the like. The amount of titanium oxide contained in the paper substrate 211 is preferably 5% by mass or more and 50% by mass or less, and more preferably 5% by mass or more and 40% by mass or less, based on the total mass of the paper substrate 211. The total mass of the paper material base material 211 means the total mass of the paper material base material 211 when dried (that is, the total mass of the solid content in the paper material base material 211).

The paper substrate 211 may be colored. In the manufacturing stage of the paper material base material 211 (for example, if the paper material base material 211 is paper, the papermaking stage), the paper material base material 211 can be colored by blending a colorant (pigment or dye) with the forming raw material. can. Further, when the cured melamine resin layer 23 is formed, a resin composition containing a colorant is used as a raw material for forming the cured melamine resin layer 23, and the paper substrate 211 is impregnated with the resin composition to obtain the paper substrate 211. Can be colored. Colorants include, for example, carbon black, iron black, titanium white, antimony white, chrome yellow, titanium yellow, petals, cadmium red, ultramarine, cobalt blue and other inorganic pigments; quinacridone red, isoindolinone yellow. Organic pigments or dyes consisting of particles such as phthalocyanine blue; metal pigments consisting of scaly foil pieces such as aluminum and brass; pearl luster pigments consisting of scaly foil pieces such as titanium dioxide-coated mica and basic lead carbonate. And so on. As the colorant, one kind may be used alone, or two or more kinds may be used in combination. The blending amount of the colorant can be appropriately adjusted according to the desired color and the like.

The paper substrate 211 may contain additives such as a filler, a matting agent, a foaming agent, a flame retardant, a lubricant, an antistatic agent, an antioxidant, an ultraviolet absorber, and a light stabilizer, if necessary. ..

Decorative layer The decorative layer 212 is provided on the surface of the paper substrate 211 on the first surface S21 side. The decorative layer 212 may be formed on the entire surface of the paper base material 211 on the first surface S21 side, or may be formed on a part of the surface of the paper base material 211 on the first surface S21 side. When the decorative layer 212 is formed on the entire surface of the paper substrate 211 on the first surface S21 side, the first surface S21 of the support layer 21 is formed by the surface of the decorative layer 212. When the decorative layer 212 is formed on a part of the surface on the first surface S21 side of the paper material material 211, the first surface S21 of the support layer 21 is a part of the surface on the first surface S21 side of the paper material base material 211 (decoration). It is formed by the portion where the layer 212 is not provided) and the surface of the decorative layer 212.

The decorative layer 212 is a layer provided as needed, and the present invention also includes an embodiment in which the decorative layer 212 is omitted. In the embodiment in which the decorative layer 212 is omitted, the first surface S21 of the support layer 21 is formed by the surface on the first surface S21 side of the paper-based base material 211.

The decorative layer 212 imparts decorativeness (design) to the decorative board 20. The decorative layer 212 is, for example, a colored layer, a pattern layer, or a combination thereof.

The colored layer imparts a desired color to the decorative board 20. The colored layer is, for example, a solid layer on the entire surface of the first surface S21 side of the paper substrate 211. The color of the colored layer is usually an opaque color, but it may be a transparent color when the color or pattern of the base such as the paper-based base material 211 is utilized. Further, when the color or pattern of the base material such as the paper base material 211 is utilized, it is not necessary to form the colored layer.

The pattern layer imparts a desired pattern to the decorative board 20. The pattern layer is, for example, a printing layer formed on a part or the whole of the surface on the first side S21 side of the paper substrate 211 or a part or the whole of the surface on the first side S21 side of the colored layer. The patterns constituting the pattern layer include, for example, a wood grain pattern composed of spring and autumn wood regions of annual ring cross sections, conduits, leather (skin grain) patterns, and stones on the surface of stone materials such as marble, granite, and sand rock. Examples include eye patterns, grain patterns, tiled patterns, brickwork patterns, cloth patterns, geometric figures, characters, symbols, and abstract patterns. As shown in FIG. 1, the decorative layer 212 in the present embodiment imparts a wood grain pattern to the decorative board 20.

The ink used to form the decorative layer 212 is, for example, a mixture of a solvent or a dispersion medium and components such as a colorant and a binder resin. The ink may contain a colorant, an extender pigment, a stabilizer, a plasticizer, a catalyst, a curing agent and the like as other components. The ink may be an aqueous composition from the viewpoint of reducing VOCs (volatile organic compounds) of the sheet.

Colorants contained in the ink include, for example, carbon black, iron black, titanium white, antimony white, yellow lead, titanium yellow, petal pattern, cadmium red, ultramarine, cobalt blue and other inorganic pigments; quinacridone red, isoindolinone. Organic pigments or dyes such as yellow and phthalocyanine blue; metal pigments made of scaly foil pieces such as aluminum and brass; titanium dioxide-coated mica, pearl pigments made of scaly foil pieces such as basic lead carbonate, etc. Can be mentioned. One type of colorant may be used alone, or two or more types may be used in combination.

Examples of the binder resin contained in the ink include urethane resin, acrylic urethane resin, vinyl chloride / vinyl acetate copolymer resin, vinyl chloride / vinyl acetate / acrylic copolymer resin, chlorinated polypropylene resin, acrylic resin, and polyester resin. , Polyamide resin, butyral resin, polystyrene resin, nitrocellulose resin (nitrated cotton), cellulose acetate resin and the like. As the binder resin, one kind may be used alone, or two or more kinds may be used in combination.

Examples of the solvent or dispersion medium contained in the ink include petroleum-based organic solvents such as hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane, and methylcyclohexane; ethyl acetate, butyl acetate, -2-methoxyethyl acetate, and acetic acid. -Ether-based organic solvent such as ethoxyethyl; alcohol-based organic solvent such as methyl alcohol, ethyl alcohol, normal propyl alcohol, isopropyl alcohol, isobutyl alcohol, ethylene glycol, propylene glycol; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc. Ketone-based organic solvent; ether-based organic solvent such as diethyl ether, dioxane, tetrahydrofuran; chlorine-based organic solvent such as dichloromethane, carbon tetrachloride, trichloroethylene, tetrachloroethylene; inorganic solvent such as water and the like. As the solvent or the dispersion medium, one type may be used alone, or two or more types may be used in combination.

The thickness of the decorative layer 212 can be appropriately adjusted, but is preferably 0.1 μm or more and 50 μm or less, and more preferably 0.1 μm or more and 20 μm or less.

Release layer The release layer 22 is provided on a part of the first surface S21 of the support layer 21. Of the first surface S21 of the support layer 21, the region where the release layer 22 is provided may be one continuous region or a plurality of discontinuous regions. The release layer 22 may be composed of one continuous layer or may be composed of a plurality of discontinuous layers. When the release layer 22 is composed of one continuous layer, the thickness of the release layer 22 may be constant or may be partially different. When the release layer 22 is composed of a plurality of discontinuous layers, the thickness of each layer may be constant or may be partially different. When the release layer 22 is composed of a plurality of discontinuous layers, the thickness of one layer and the thickness of another layer may be the same or different. The thickness of the release layer 22 can be appropriately adjusted, but is preferably 0.1 μm or more and 50 μm or less, and more preferably 0.1 μm or more and 20 μm or less.

The release layer 22 is preferably formed on the first surface S21 of the support layer 21 in a predetermined pattern (pattern pattern), and is visually recessed or has low gloss (艷) among the pattern patterns formed by the decorative layer 212. It is more preferable that the pattern is aligned with the region to be erased). As a pattern formed by the release layer 22, for example, when the decorative layer 212 has a wood grain pattern, a conduit portion of the wood grain board, a concave portion such as a spring wood region or a low gloss region, and when the decorative layer 212 has a stone grain pattern, a recess of a travertin marble plate. Part, stone plate surface unevenness such as recesses on the open surface of the granite board, cloth surface texture in the case of cloth pattern, wrinkle shape of leather grain in the case of leather pattern, joint recess in the case of tiled pattern or brick pile pattern, etc. In addition, there are patterns such as pear-skin texture, grain, hairline, perforated groove, letters, symbols, and geometric patterns.

The release layer 22 is a layer formed by curing the ionizing radiation curable resin composition, and contains a cured product of the ionizing radiation curable resin.

The description of the ionizing radiation curable resin composition used as the composition for forming the release layer 22 (the composition for forming the release layer) is the same as described above.

The release layer 22 may contain a silicone-based release agent. The silicone-based mold release agent contained in the mold release layer 22 is derived from the silicone-based mold release agent (silicone oil) added to the release layer forming composition. Since the silicone-based mold release agent is oriented on the surface of the release layer 22 when the release layer forming composition is cured, the release property of the release layer 22 is improved. The silicone-based mold release agent added to the release layer forming composition may be a reactive silicone-based mold release agent or a non-reactive silicone-based mold release agent. When the silicone-based mold release agent added to the release layer forming composition is a reactive silicone-based mold release agent, the silicone-based mold release agent is the other component of the release layer 22 (for example, a curable resin). It can be contained in the release layer 22 in a state of being bonded to a cured product or the like). One type of silicone release agent may be used alone, or two or more types may be used in combination.

The amount of the silicone-based mold release agent contained in the release layer forming composition is usually 0.1 to 50 parts by mass with respect to 100 parts by mass of the ionized radiation curable resin contained in the release layer forming composition. It is preferably 0.5 to 20 parts by mass, more preferably 3 to 20 parts by mass, and even more preferably 3 to 10 parts by mass. When the amount of the silicone-based mold release agent is within the above range, the mold release property of the mold release layer 22 can be effectively improved.

The silicone-based mold release agent is a modified silicone having an organopolysiloxane structure as a basic structure and having an organic group introduced into a side chain and / or a terminal. The end into which the organic machine is introduced may be one end or both ends.

The reactive silicone-based mold release agent refers to a modified silicone having an organic group introduced into the side chain and / or the terminal, which is reactive depending on the nature of the organic group to be introduced. Examples of the reactive silicone-based release agent include amino-modified silicone, epoxy-modified silicone, mercapto-modified silicone, carboxyl-modified silicone, carbinol-modified silicone, phenol-modified silicone, methacryl-modified silicone, and heterogeneous functional group-modified silicone. .. More specifically, amino-modified polydimethylsiloxane, epoxy-modified polydimethylsiloxane, mercapto-modified polydimethylsiloxane, carboxyl-modified polydimethylsiloxane, carbinol-modified polydimethylsiloxane, phenol-modified polydimethylsiloxane, methacryl-modified polydimethylsiloxane, heterologous. Examples thereof include functional group-modified polydimethylsiloxane. As the reactive silicone-based mold release agent, one type may be used alone, or two or more types may be used in combination.

The non-reactive silicone-based release agent is not particularly limited as long as it is a silicone having no reactive functional group such as an amino group, an epoxy group, a mercapto group, a carboxy group, a hydroxy group, a (meth) acryloyl group and an allyl group. Examples of the non-reactive silicone-based release agent include silicone composed of polysiloxane, polyether-modified silicone, aralkyl-modified silicone, fluoroalkyl-modified silicone, long-chain alkyl-modified silicone, higher fatty acid ester-modified silicone, and higher fatty acid amide. Examples thereof include modified silicone and phenyl-modified silicone. More specifically, polyether-modified polydimethylsiloxane, aralkyl-modified polydimethylsiloxane, fluoroalkyl-modified polydimethylsiloxane, long-chain alkyl-modified polydimethylsiloxane, higher fatty acid ester-modified polydimethylsiloxane, higher fatty acid amide-modified polydimethylsiloxane, Examples thereof include phenyl-modified polydimethylsiloxane. One type of non-reactive silicone-based mold release agent may be used alone, or two or more types may be used in combination.

It is preferable to use a polyether-modified silicone as the silicone-based mold release agent. The polyether-modified silicone has a polysiloxane main chain and has one or more polyoxyalkylene groups as substituents. The main chain may form a ring.

The bonding position of the polyoxyalkylene group in the polyether-modified silicone can be any suitable bonding position. For example, the polyoxyalkylene group may be attached to both ends of the main chain, to one end of the main chain, or to the side chain. The polyether-modified silicone is preferably a side-chain type polyether-modified silicone in which a polyoxyalkylene group is bonded to a side chain.

The side-chain type polyether-modified silicone is represented by, for example, the general formula (1).

In the general formula (1), R independently represents an alkyl group having 1 to 3 carbon atoms, R ¹ represents an alkylene group having 1 to 4 carbon atoms, and R ² represents a hydrogen atom or 1 to 15 carbon atoms. Representing an alkyl group, R ³ is a polyoxyalkylene group represented by-(C ₂ H ₄ O) _a- (C ₃ H ₆ O) _b- , a is 1 to 50, and b is 0 to 0. It is 30, m is 1 to 7000, and n is 1 to 50.

In the general formula (1), R is preferably a methyl group.

Examples of the polyether-modified silicone include trade names "KF-6011" (HLB: 14.5), "KF-6011P" (HLB: 14.5), and "KF-6012" manufactured by Shin-Etsu Silicone Co., Ltd. HLB: 7.0), "KF-6013" (HLB: 10.0), "KF-6015" (HLB: 4.5), "KF-6016" (HLB: 4.5), "KF-6017" (HLB: 4.5), "KF-6017P" (HLB: 4.5), "KF-6043" (HLB: 14.5), "KF-6004" (HLB: 9.0), "KF351A" (HLB: 12), "KF352A" (HLB: 7), "KF353" (HLB: 10), "KF354L" (HLB: 16), "KF355A" (HLB: 12), "KF615A" (HLB: 10) ), "KF945" (HLB: 4), "KF-640" (HLB: 14), "KF-642" (HLB: 12), "KF-643" (HLB: 14), "KF-644" ( HLB: 11), "KF-6020" (HLB: 4), "KF-6204" (HLB: 10), "X22-4515" (HLB: 5), etc. Silicone oil; side chain type (branched chain type) polyether modification such as trade name "KF-6028" (HLB: 4.0), "KF-6028P" (HLB: 4.0) manufactured by Shin-Etsu Silicone Co., Ltd. Silicone oil; Side chain type (branched chain type, alkyl co-modified type) polyether-modified silicone oil such as trade name "KF-6038" (HLB: 3.0) manufactured by Shin-Etsu Silicone Co., Ltd. can be mentioned.

The release layer forming composition preferably contains an extender pigment. Thereby, thixotropic property can be imparted to the release layer forming composition, and the pattern shape of the release layer forming composition is maintained when the release layer forming composition is printed using the plate. Can be made to. Examples of the extender pigment include silica, talc, clay, barium sulfate, barium carbonate, calcium sulfate, calcium carbonate, magnesium carbonate and the like. Of these, silica, which has a high degree of freedom in material design and is excellent in designability, whiteness, and coating stability as an ink, is preferable, and fine powder silica is particularly preferable.

The amount of the extender pigment contained in the release layer forming composition is usually 0.1 part by mass or more and 20 parts by mass or less, preferably 0, with respect to 100 parts by mass of the resin contained in the release layer forming composition. It is 5 parts by mass or less, more preferably 2 parts by mass or more and 15 parts by mass or less, and even more preferably 5 parts by mass or more and 15 parts by mass or less. By setting the content of the extender pigment in the above range, it is possible to impart sufficient thixotropy to the composition for forming a release layer, and it is possible to obtain an effect of imparting a raised shape and a fine uneven surface.

The release layer forming composition may be colorless or colored. In the case of coloring, the same colorant as that used in the decorative layer can be used.

The release layer forming composition may contain a solvent for the purpose of adjusting the viscosity. As the solvent, water; hydrocarbon compounds such as toluene and xylene; alcohol compounds such as methanol, ethanol and methyl glycol; ketone compounds such as acetone and methyl ethyl ketone; ester compounds such as methyl formate and ethyl acetate; N-methylpyrrolidone and N. , Nitrogen-containing compounds such as N-dimethylformamide; ether compounds such as terrorahydrofuran and dioxane; halogenated hydrocarbon compounds such as methylene chloride and chloroform; dimethyl sulfoxide and the like. These solvents can be used alone or in admixture of two or more. The amount of the solvent in the release layer forming composition can be appropriately set according to the viscosity required for the release layer forming composition.

A known additive can be appropriately added to the release layer forming composition according to the desired physical characteristics. As additives, for example, ultraviolet absorbers, infrared absorbers, light stabilizers, polymerization inhibitors, cross-linking agents, antistatic agents, antioxidants, leveling agents, coupling agents, plasticizers, defoaming agents, fillers, etc. Examples thereof include a thermal radical generator and an aluminum chelating agent.

Cured melamine layer As shown in FIGS. 3 to 5, the cured melamine resin layer 23 is provided on the rest of the first surface S21 of the support layer 21 and surrounds a part or the whole of the release layer 22. The rest of the first surface S21 of the support layer 21 means a region of the first surface S21 of the support layer 21 in which the release layer 22 is not formed. Of the first surface S21 of the support layer 21, the region where the cured melamine resin layer 23 is formed may be the entire remaining portion of the first surface S21 or a part of the remaining portion of the first surface S21. May be good. Of the first surface S21 of the support layer 21, the region where the cured melamine resin layer 23 is formed may be one continuous region or a plurality of discontinuous regions. The cured melamine resin layer 23 may be composed of one continuous layer or may be composed of a plurality of discontinuous layers. When the cured melamine resin layer 23 is composed of one continuous layer, the thickness of the cured melamine resin layer 23 may be constant or may be partially different. When the cured melamine resin layer 23 is composed of a plurality of discontinuous layers, the thickness of each layer may be constant or may be partially different. When the cured melamine resin layer 23 is composed of a plurality of discontinuous layers, the thickness of one layer and the thickness of another layer may be the same or different.

The ratio (Sa: Sb) of the area (Sa) of the region where the cured melamine resin layer 23 is formed and the area (Sb) where the release layer 22 is formed in the first surface S21 of the support layer 21 is. It is preferably 3: 7 to 9: 1, and more preferably 5: 5 to 8: 2. When the area ratio is within the above range, the design feeling of the uneven shape expressed by the decorative board 20 becomes clearer.

As shown in FIGS. 3 to 5, the cured melamine resin layer 23 has an opening 230 that exposes the surface S22 of the release layer 22. The opening 230 of the cured melamine resin layer 23 is position-tuned with the release layer 22 in a plan view. In the present invention, "positional tuning" means that at least a part of the opening 230 of the cured melamine resin layer 23 overlaps with at least a part of the release layer 22 in a plan view. The opening 230 of the cured melamine resin layer 23 may have a portion that does not overlap with the release layer 22 in a plan view, but the entire opening 230 of the cured melamine resin layer 23 is at least the release layer 22. It is preferable that it overlaps with a part. The release layer 22 may have a portion that does not overlap with the opening 230 of the cured melamine resin layer 23 in a plan view.

In the present invention, "planar view" means observing the target member or portion from the thickness direction Z of the decorative plate 20. For example, in FIGS. 4 and 5, it means looking down from above toward the figure. Further, "planar view" is a virtual concept that treats a target member or part as being observable even when it is hidden by other members or parts and cannot be actually observed. That is, "plan view" corresponds to projecting the target member or portion onto a virtual plane perpendicular to the thickness direction Z of the decorative board 20.

As shown in FIGS. 3 to 5, the opening 230 of the cured melamine resin layer 23 forms a recess 25 on the first surface S20 of the decorative plate 20, and the bottom surface of the recess 25 is the surface of the release layer 22. It is formed by S22.

The depth of the recess 25 is preferably 0.1 μm or more and 50 μm or less, and more preferably 0.1 μm or more and 30 μm or less. When the depth of the concave portion 25 is within the above range, the design feeling of the uneven shape expressed by the decorative plate 20 becomes clear.

The depth of the recess 25 is such that the region where the mold release layer 22 is not formed (the region where the cured melamine resin layer 23 is formed) and the mold release layer 22 are formed in the first surface S20 of the decorative plate 20. It is measured as the height difference from the area where the resin is. The measurement is carried out using a three-dimensional surface roughness measuring instrument SE-30K manufactured by Kosaka Laboratory Co., Ltd. according to the method specified in JIS B 0601: 2013. The maximum height roughness (Rz) of the surface is used as a parameter of the height difference, and the average value of 10 points is defined as the "height difference".

As shown in FIGS. 3 to 5, in the first surface S20 of the decorative board 20, the region adjacent to the concave portion 25 (the region formed by the surface S23 of the cured melamine resin layer 23) is relatively convex. The first surface S20 of the decorative plate 20 is formed with an uneven shape. Of the first surface S20 of the decorative plate 20, the region formed by the bottom surface of the recess 25 (the surface S22 of the release layer 22) is a relatively rough surface, and is a low gloss region having diffuse reflection with respect to incident light. On the other hand, in the first surface S20 of the decorative plate 20, the region adjacent to the recess 25 (the region formed by the surface S23 of the cured melamine resin layer 23) is relatively mirror-finished and mirror-reflected with respect to the incident light. It is a highly glossy region with properties. As a result, the decorative board 20 can express a gloss matte-like design feeling based on the uneven shape. In particular, by aligning the uneven shape of the decorative board 20 (that is, the high gloss area and the low gloss area) with the pattern of the decorative layer 212, the decorative board 20 expresses an excellent gloss matte design feeling. be able to. For example, when the decorative layer 212 forms a wood grain pattern, the recess 25 is positioned at the conduit portion in the wood grain pattern (that is, the groove portion of the streak formed by the cut surface opening of the conduit) and the position in the plan view of both. In the wood grain pattern, the area adjacent to the recess 25 is aligned with the area other than the conduit part in the wood grain pattern so that the positions of the two are aligned in the plan view. The conduit portion of the above has a relatively concave appearance, whereby the decorative board 20 can express the design feeling (texture) of the surface uneven shape similar to the real wood grain pattern.

The entire surface S22 of the release layer 22 may be exposed from the opening 230 of the cured melamine resin layer 23 to form the bottom surface of the recess 25, but this is not always necessary. A part of the surface S22 of the release layer 22 may be covered with the cured melamine resin layer 23. In particular, when the release layer 22 is position-synchronized with the wood grain-patterned conduit portion formed by the decorative layer 212, the portion of the release layer 22 corresponding to the peripheral edge portion of the conduit portion is covered with the cured melamine resin layer 23. May be. It should be noted that the height difference of the uneven shape composed of the concave portion 25 and the convex portion (cured melamine resin layer 23) is sufficiently secured in the visual appearance, and the surface physical properties such as wear resistance are not hindered in practical use. The cured melamine resin layer 23 may remain in a trace amount as a residue or a trace over the entire surface S22 of the release layer 22. When the decorative plate 20 is viewed in a plan view, the area of the portion of the release layer 22 that is exposed from the opening 230 of the cured melamine resin layer 23 and forms the bottom surface of the recess 25 is the first surface S21 of the support layer 21. Of these, it is preferably 50% or more of the area of the region where the release layer 22 is provided. As a result, the decorative board 20 can express the design feeling of the uneven shape.

A recess other than the recess 25 may be formed on the first surface S20 of the decorative plate 20. For example, a recess may be formed on the surface S23 of the cured melamine resin layer 23.

The cured melamine resin layer 23 is a layer formed by curing the uncured melamine resin layer, and contains a cured product of the melamine resin.

The uncured melamine resin layer is a layer formed by the uncured melamine resin composition and contains an uncured product of the melamine resin. The uncured melamine resin composition contains an uncured product of the melamine resin. The uncured melamine resin is a thermosetting resin obtained by reacting melamine and formaldehyde under neutral or alkaline conditions, and the reaction product (initial condensate) of melamine and formaldehyde is methylol melamines. Includes (monomethylol melamine, dimethylol melamine, hexamethylol melamine).

The uncured melamine resin composition may contain a solvent for the purpose of adjusting the viscosity. As the solvent, water; hydrocarbon compounds such as toluene and xylene; alcohol compounds such as methanol, ethanol and methyl glycol; ketone compounds such as acetone and methyl ethyl ketone; ester compounds such as methyl formate and ethyl acetate; N-methylpyrrolidone and N. , Nitrogen-containing compounds such as N-dimethylformamide; ether compounds such as terrorahydrofuran and dioxane; halogenated hydrocarbon compounds such as methylene chloride and chloroform; dimethyl sulfoxide and the like. These solvents can be used alone or in admixture of two or more. The amount of the solvent in the uncured melamine resin composition can be appropriately set according to the viscosity of the uncured melamine resin composition.

A known additive can be appropriately added to the uncured melamine resin composition according to the desired physical characteristics. As additives, for example, ultraviolet absorbers, infrared absorbers, light stabilizers, polymerization inhibitors, cross-linking agents, antistatic agents, antioxidants, leveling agents, coupling agents, plasticizers, defoaming agents, fillers, etc. Examples thereof include a thermal radical generator and an aluminum chelating agent.

The thickness of the cured melamine resin layer 23 can be appropriately adjusted in relation to the thickness of the release layer 22, but is preferably 1 μm or more and 500 μm or less, and more preferably 1 μm or more and 300 μm or less.

In the decorative plate 20, the voids of the paper-based base material 211 are filled with the cured product of the melamine resin, and the cured product of the melamine resin contained in the cured melamine resin layer 23 is filled in the voids of the paper-based base material 211. It is integrated with the cured product of melamine resin. As a result, the bonding strength between the support layer 21 and the cured melamine resin layer 23 can be improved, and the cured melamine resin layer 23 is less likely to be peeled off from the support layer 21 when the decorative plate 20 is used.

Core layer The core layer 24 can be configured in the same manner as the core layer generally used in the field of decorative boards. The core layer 24 has, for example, a porous base material and a cured product of a thermosetting resin filled in the voids of the porous base material.

Examples of the porous substrate include a fiber sheet and the like. Examples of the fiber sheet include paper, non-woven fabric, and woven fabric. Examples of paper include titanium paper, thin leaf paper, kraft paper, linter paper, paperboard, gypsum board paper, so-called vinyl wallpaper raw fabric obtained by sol-coating or dry-laminating polyvinyl chloride resin on paper, high-quality paper, coated paper, and parchment paper. Japanese paper and the like can be mentioned. Examples of other fiber sheets include sheets composed of inorganic fibers such as glass fibers, asbestos, potassium titanate fibers, alumina fibers, silica fibers and carbon fibers; synthetic resin fibers such as polyester, vinylon, polyethylene and polypropylene. Examples include sheets to be constructed.

Examples of the thermosetting resin include phenol resin, unsaturated polyester resin, polyurethane resin (including two-component curable polyurethane), epoxy resin, aminoalkyd resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, and melamine. -Urea cocondensation resin, silicon resin, polysiloxane resin and the like can be mentioned.

As the precursor layer of the core layer 24, for example, a thermosetting resin impregnated sheet can be used. The core layer 24 can be formed, for example, by heating a thermosetting resin impregnated sheet to cure the thermosetting resin. Examples of the thermosetting resin-impregnated sheet include phenol resin-impregnated paper, which is widely used as the core paper for melamine decorative boards. The thermosetting resin can be cured, for example, in the step of thermosetting the thermosetting resin impregnated sheet together with other layers.

The phenol resin impregnated paper is, for example, impregnated kraft paper having a basis weight of 150 g / m ² or more and 250 g / m ² or less as core paper with a phenol resin so as to have an impregnation rate of 45% or more and 60% or less, and 100 ° C. or more and 140 ° C. It can be manufactured by drying below. Commercially available phenol resin impregnated paper may be used.

The thermosetting resin impregnated sheet may be a prepreg using a glass cloth or a glass non-woven fabric as a base material. The prepreg can be produced, for example, by impregnating a glass cloth or a glass nonwoven fabric with a thermosetting resin.

The thickness of the core layer 24 can be appropriately adjusted, but is preferably 300 μm or more and 1750 μm or less, and more preferably 300 μm or more and 1400 μm or less.

The decorative board 20 may have a reinforcing layer laminated on one surface or both surfaces of the core layer 24, if necessary. For example, in order to conceal that the blackish brown color tone of the core paper is seen through from the surface of the decorative plate 20, a barrier paper made of titanium paper mixed with titanium white pigment is placed between the core layer 24 and the support layer 21. Can be laminated. Further, in order to offset the warp of the decorative plate 20 generated during thermal pressure molding, a balance paper or the like made of titanium paper is laminated on the back surface of the core layer 24 (the surface on the second surface T20 side of the core layer 24). be able to. These reinforcing layers can be integrated with other layers by impregnating the resin composition in an uncured state containing a thermosetting resin such as melamine resin and then hot-press molding together with the other layers. ..

<Manufacturing method of decorative board>
Hereinafter, an embodiment of a method for manufacturing the decorative board 20 will be described with reference to the drawings. 6 to 8 are explanatory views for explaining an embodiment of a method for manufacturing a decorative board 20. 7 is a continuation of FIG. 6, and FIG. 8 is a continuation of FIG. 7.

The method for manufacturing the decorative board 20 according to the present embodiment is as follows.
(1) A support layer 21 having a second surface T21 located on the opposite side of the first surface S21 and the first surface S21, and a release layer 22 provided on a part of the first surface S21 of the support layer 21. The uncured melamine resin layer L1 that covers the rest of the first surface S21 of the support layer 21 and the release layer 22 and the uncured melamine resin layer L1 so that the first surface S10 of the release sheet 10 is in contact with the uncured melamine resin layer L1. A step of preparing a laminated body M3 including a release sheet 10 provided on the layer L1 and a precursor layer L2 of a core layer 24 provided on the second surface T21 of the support layer 21.
(2) The step of curing the uncured melamine resin layer L1 by pressurizing and heating the laminated body M3 to form the cured melamine resin layer 23, and (3) the step of peeling the release sheet 10 to cure the cured melamine. A step of peeling off the portion 231 of the resin layer 23 that covers the release layer 22 and forming an opening 230 in the cured melamine resin layer 23 that exposes the surface S22 of the release layer 22 is included.
Hereinafter, each step will be described.

Process (1)
The step (1) is a step of preparing the laminated body M3. The laminated body M3 can be produced by a method including the following steps (1-1) to (1-4).

Step (1-1) is a step of preparing a support layer 21 having a second surface T21 located on the opposite side of the first surface S21 and the first surface S21, as shown in FIG. 6A.

The support layer 21 can be manufactured by forming the decorative layer 212 on the surface of the paper substrate 211 on the first surface S21 side. Examples of the method for forming the decorative layer 212 using ink include a coating method and a printing method. Examples of the coating method include a roll coating method, a knife coating method, an air knife coating method, a die coating method, a lip coating method, a comma coating method, a kiss coating method, a flow coating method, and a dip coating method. Examples of the printing method include a gravure printing method, an offset printing method, a screen printing method, a flexographic printing method, an electrostatic printing method, an inkjet printing method, and the like.

An easy-adhesive layer may be formed on the surface of the paper substrate 211 on the first surface S21 side before the decorative layer 212 is formed on the surface of the paper substrate 211 on the first surface S21 side. Examples of the easy-adhesive resin contained in the easy-adhesion layer (sometimes called a primer layer or an anchor layer) include acrylic resin, vinyl chloride-vinyl acetate copolymer, polyester resin, urethane resin, chlorinated polypropylene, and chlorine. Examples include polyethylene chemicals. This makes it possible to improve the adhesion of the decorative layer 212.

Before forming the decorative layer 212 on the surface of the paper base material 211 on the first surface S21 side, the surface of the paper base material 211 on the first surface S21 side is subjected to physical or chemical surface treatment such as an oxidation method or an unevenness method. May be given. This makes it possible to improve the adhesion of the decorative layer 212. Examples of the oxidation method include corona discharge treatment, chromium oxidation treatment, flame treatment, hot air treatment, ozone / ultraviolet treatment method and the like, and examples of the unevenness method include sandblasting method and solvent treatment method.

The thickness of the decorative layer 212 can be appropriately adjusted, but the thickness at the time of ink coating is, for example, 1 μm or more and 200 μm or less, and the thickness after drying is, for example, 0.1 μm or more and 20 μm or less.

The decorative layer 212 may be formed by a method such as a hand-painting method, a suminagashi method, a photographic method, a transfer method, a laser beam drawing method, or an electron beam drawing method. When the decorative layer 212 is a metal layer (metal thin film) such as aluminum, chromium, gold, silver, and copper, the decorative layer 212 can be formed by a method such as a vapor deposition method, a sputtering method, or an etching method.

Process (1-2)
The step (1-2) is a step of forming the release layer 22 on a part of the first surface S21 of the support layer 21, as shown in FIG. 6 (b). In the step (1-2), the laminated body M1 including the support layer 21 and the release layer 22 formed on a part of the first surface S21 of the support layer 21 is formed.

The release layer 22 is formed by printing an ionizing radiation curable resin composition used as a composition for forming a release layer on a part of the first surface S21 of the support layer 21 in a predetermined pattern and irradiating the release layer 22 with ionizing radiation. It can be formed by curing it. When the release layer forming composition contains a silicone-based release agent (silicone oil), the silicone-based release agent is oriented on the surface of the release layer 22 when the release layer forming composition is cured. The releasability of the releasable layer 22 is improved. As a result, in the step (3), when the portion 231 covering the release layer 22 of the cured melamine resin layer 23 is peeled off, the portion 231 is easily peeled off from the release layer 22.

Examples of the method for printing the release layer forming composition include a gravure printing method, an offset printing method, a screen printing method, a flexographic printing method, an electrostatic printing method, and an inkjet printing method. The release layer forming composition may be applied to a part of the first surface S21 of the support layer 21 by a method other than the printing method, and as a method of applying the release layer forming composition, for example, a roll. Examples include a coating method such as a coating method and a gravure coating method. The thickness of the release layer forming composition at the time of coating (thickness before drying) is preferably 1 μm or more and 200 μm or less, more preferably 1 μm or more and 100 μm or less, and the thickness after drying is preferably 1 μm or more and 40 μm or less. It is more preferably 1 μm or more and 20 μm or less.

When ultraviolet rays are used as ionizing radiation, a light source such as an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc lamp, a black light fluorescent lamp, or a metal halide lamp can be used as the ultraviolet source. The wavelength of ultraviolet rays is, for example, 190 nm or more and 380 nm or less. When an electron beam is used as ionizing radiation, the electron beam source may be, for example, an electron such as a Cockcroft-Walth type, a Van de Graaff type, a resonance transformer type, an insulated core transformer type, a linear type, a dynamitron type, or a high frequency type. A line accelerator can be used. The energy of the electron beam is usually 100 keV or more and 1000 keV or less, preferably 100 keV or more and 300 keV or less. The irradiation amount of the electron beam is preferably 2 Mrad or more and 15 Mrad or less.

Process (1-3)
In the step (1-3), as shown in FIG. 6 (c), the uncured melamine resin composition is supplied to the laminated body M1, and the rest of the first surface S21 of the support layer 21 (the first surface of the support layer 21). This is a step of forming a laminated body M2 including a region of S21 in which the release layer 22 is not formed) and an uncured melamine resin layer L1 that covers the release layer 22.

When supplying the uncured melamine resin composition to the laminate M1, the uncured melamine resin composition is supplied, for example, from the first surface S21 side of the support layer 21. Of the supplied uncured melamine resin composition, a part of the uncured melamine resin composition is impregnated into the paper base material 211, and the rest not impregnated by the paper material base material 211 covers the rest of the first surface S21 of the support layer 21 and the release layer 22. do. The uncured melamine resin composition is not impregnated into the release layer 22, but covers the release layer 22. In order to promote the impregnation of the uncured melamine resin composition into the paper substrate 211, in addition to the supply of the uncured melamine resin composition from the first surface S21 side of the support layer 21, the second surface of the support layer 21 The uncured melamine resin composition may be supplied from the T21 side. Only the uncured melamine resin composition may be supplied from the second surface T21 side of the support layer 21. Similarly, when only the uncured melamine resin composition is supplied from the second surface T21 side of the support layer 21, a part of the supplied uncured melamine resin composition is impregnated into the paper substrate 211. The remaining portion that is not impregnated into the paper base material 211 covers the remaining portion of the first surface S21 of the support layer 21 and the release layer 22. Examples of the method for supplying the uncured melamine resin composition include immersion in the uncured melamine resin composition; application by a coater such as a kiss coater and a comma coater; and spraying by a spray device, a shower device and the like.

The thickness of the uncured melamine resin layer L1 can be appropriately adjusted in relation to the thickness of the release layer 22, but the thickness at the time of coating (thickness before drying) is preferably 1 μm or more and 800 μm or less, more preferably. Is 1 μm or more and 500 μm or less, and the thickness after drying is preferably 1 μm or more and 500 μm or less, and more preferably 1 μm or more and 300 μm or less.

When the uncured melamine resin composition is impregnated into the paper substrate 211, the uncured melamine resin composition is filled in the voids of the paper substrate 211. Therefore, the laminate M2 contains an uncured melamine resin filled in the voids of the paper substrate 211. By impregnating the voids of the paper base material 211 with the uncured melamine resin, the cured product of the melamine resin contained in the cured melamine resin layer 23 becomes the cured product of the melamine resin filled in the voids of the paper base material 211. Can be integrated. As a result, the bonding strength between the support layer 21 and the cured melamine resin layer 23 can be improved, and the cured melamine resin layer 23 is less likely to be peeled off from the support layer 21 when the decorative plate 20 is used.

The filling rate of the uncured melamine resin composition filled in the voids of the paper-based substrate 211 can be appropriately adjusted according to the performance required for the decorative board 20, the porosity of the paper-based substrate 211 and the like. The filling rate of the uncured melamine resin composition is preferably 30% or more and 200% or less, and more preferably 50% or more and 150% or less. The filling rate of the resin composition is calculated by the following formula.
Filling rate (%) = [(Weight of paper substrate after impregnation with resin composition-Weight of paper substrate before impregnation with resin composition) / Weight of paper substrate before impregnation with resin composition) Weight] x 100

The uncured melamine resin composition may cover at least a part of the release layer 22. The uncured melamine resin composition in the total area occupied by the release layer 22 in the first surface S21 of the support layer 21 (the area of the region where the release layer 22 is provided in the first surface S21 of the support layer 21). The area of the portion covered with the object is, for example, 30% or more, preferably 50% or more. The upper limit is 100%.

Process (1-4)
In the step (1-4), as shown in FIG. 6D, the release sheet 10 is laminated on the uncured melamine resin layer L1, and the precursor layer L2 of the core layer 24 is formed on the second surface T21 of the support layer 21. This is the process of laminating. In step (1-4), the support layer 21, the release layer 22 formed on a part of the first surface S21 of the support layer 21, and the rest of the first surface S21 of the support layer 21 (the first of the support layer 21). The uncured melamine resin layer L1 that covers the release layer 22 (the region of the one surface S21 where the release layer 22 is not formed), the release sheet 10 laminated on the uncured melamine resin layer L1, and the support layer 21. A laminated body M3 including the precursor layer L2 of the core layer 24 laminated on the second surface T21 of the above is formed. The laminating of the release sheet 10 on the uncured melamine resin layer L1 may be performed at any time before or after laminating the core layer 24 on the second surface T21 of the support layer 21.

As shown in FIG. 6D, the release sheet 10 is laminated on the uncured melamine resin layer L1 so that the first surface S10 of the release sheet 10 is in contact with the uncured melamine resin layer L1.

Process (2)
The step (2) is a step of curing the uncured melamine resin layer L1 by pressurizing and heating the laminated body M3 to form the cured melamine resin layer 23.

The pressurization and heating of the laminated body M3 can be performed, for example, in a state where the laminated body M3 is sandwiched between two mirror-finished metal plates MP1 and MP2, as shown in FIG. 6 (e). The pressure applied by the mirror-finished metal plates MP1 and MP2 is usually 0.1 kg / cm ² or more and 200 kg / cm ² or less. The heating temperature is usually 100 ° C. or higher and 200 ° C. or lower, and the heating time is usually 1 second or longer and 120 minutes or shorter.

By pressurizing and heating the laminate M3, the uncured melamine resin layer L1 is cured to form the cured melamine resin layer 23, and the precursor layer L2 of the core layer 24 is cured to form the core layer 24. The uncured melamine resin filled in the voids of the paper substrate 211 is also cured at this stage, and the cured melamine resin filled in the voids of the paper substrate 211 and the melamine resin contained in the cured melamine resin layer 23. Is integrated with the cured product of. The surface layer 12 of the release sheet 10 is bonded to the cured melamine resin layer 23 at this stage.

As a result, as shown in FIG. 7 (f), the support layer 21, the release layer 22 formed on a part of the first surface S21 of the support layer 21, and the rest of the first surface S21 of the support layer 21 ( A region of the first surface S21 of the support layer 21 in which the release layer 22 is not formed), a cured melamine resin layer 23 that covers the release layer 22, and a release sheet 10 laminated on the cured melamine resin layer 23. A laminated body M4 including a core layer 24 laminated on the second surface T21 of the support layer 21 is formed.

As shown in FIG. 7 (f), the cured melamine resin layer 23 has a portion 231 that covers the release layer 22 and a portion 232 that does not cover the release layer 22. The portion 231 that covers the release layer 22 is formed on the surface S22 of the release layer 22 so as to cover the release layer 22. The portion 232 that does not cover the release layer 22 is formed on the first surface S21 of the support layer 21 so as to surround the release layer 22.

Process (3)
In the step (3), as shown in FIG. 7 (g), the release sheet 10 is peeled off from the laminated body M4 to peel off the portion 231 of the cured melamine resin layer 23 that covers the release layer 22, and is cured. This is a step of forming an opening 230 in the melamine resin layer 23 to expose the surface S22 of the release layer 22.

The portion 231 of the cured melamine resin layer 23 that covers the release layer 22 is more easily peeled off than the portion 232 that does not cover the release layer 22. Therefore, the portion 231 covering the release layer 22 is peeled off together with the release sheet 10 while being bonded to the release sheet 10. On the other hand, the portion 232 that does not cover the release layer 22 remains in the rest of the first surface S21 of the support layer 21. By removing the portion 231 that covers the release layer 22, an opening 230 is formed in the cured melamine resin layer 23, and the surface S22 of the release layer 22 passes through the opening 230 of the cured melamine resin layer 23. It is exposed and a recess 25 is formed on the first surface S20 of the decorative plate 20. As a result, as shown in FIG. 7 (h), the decorative board 20 is manufactured.

When the release layer 22 contains a silicone-based release agent, the release layer 22 is imparted with a release property by the silicone-based release agent. Therefore, in the step (3), the portion 231 covering the release layer 22 Is easy to peel off. When both the release layer 22 and the cured melamine resin layer 23 contain a silicone-based release agent, this effect is enhanced.

The bonding strength between the surface layer 12 of the release sheet 10 and the cured melamine resin layer 23 is based on the bonding strength between the release target portion (the portion 231 of the cured melamine resin layer 23 that covers the release layer 22) and the release layer 22. Is also large, smaller than the bonding strength between the rest of the cured melamine resin layer 23 (the portion 232 that does not cover the release layer 22) and the support layer 21, and smaller than the bonding strength between the release layer 22 and the support layer 21. It is adjusted to be. However, if the bonding strength between the surface layer 12 of the peeling sheet 10 and the cured melamine resin layer 23 is not sufficiently high, the peeling target portion is not sufficiently peeled and a part of the peeling target portion is on the release layer 22. It may remain. Therefore, when mass-producing decorative boards, even if there are variations in the hot press conditions at the time of manufacture, the composition of the melamine resin composition used for forming the cured melamine resin layer, etc. to the extent normally expected, the release sheet is still released. By peeling of 10, the portion to be peeled from the release layer 22 directly above the release layer 22 is stably peeled (removed) together with the release sheet 10 (as a result, a recess 25 is formed on the first surface S20 of the decorative plate 20). The peeling weight of the peeling sheet 10, which is an index of the bonding strength between the surface layer 12 of the peeling sheet 10 and the cured melamine resin layer 23, is preferably 1N / inch or more, preferably 1.5N. It is more preferably / inch or more, and even more preferably 2N / inch or more. When the peeling weight of the peeling sheet 10 is 1 N / inch or more, the peeling target portion can be sufficiently peeled. The upper limit of the peeling weight of the peeling sheet 10 is preferably 10 N / inch, more preferably 5 N / inch, and even more preferably 3 N / inch. If the peeling weight exceeds 10 N / inch, the peeling sheet 10 may be broken or the portion of the cured melamine resin layer 23 other than the peeling target portion may be peeled off.

The method for measuring the peeling weight of the peeling sheet 10 is as follows. A laminated body sample M4'having the same structure as the laminated body M4 is prepared except that the release layer 22 is not provided. As shown in FIG. 8, the laminated body sample M4'is provided on the support layer 21 having the second surface T21 located on the opposite side of the first surface S21 and the first surface S21, and the first surface S21 of the support layer 21. The cured melamine resin layer 23 is provided with a release sheet 10 laminated on the cured melamine resin layer 23, and a core layer 24 laminated on the second surface T21 of the support layer 21. The laminated body sample M4'is produced by the same method as the laminated body M4 except that the release layer 22 is not formed. That is, the release sheet 10 is laminated on the uncured melamine resin layer so that the first surface S10 is in contact with the uncured melamine resin layer, and then pressurized and heated together with the uncured melamine resin layer to press and heat the surface of the release sheet 10. The layer 12 is bonded to the cured melamine resin layer 23 formed by curing the uncured melamine resin layer. At this time, the bonding strength between the cured melamine resin layer 23 and the support layer 21 is adjusted so that the cured melamine resin layer 23 does not peel off from the support layer 21 even if the release sheet 10 is peeled from the cured melamine resin layer 23. After preparing the laminate sample M4', make a 1-inch wide notch in the release sheet 10, peel off one end of the cut release sheet 10, and then use one end (lower part) of the laminate sample M4'as a testing machine. Fix it. The weight when the peeling sheet 10 peeled off by 180 ° is peeled off at a speed of 100 mm / min in the upper direction (arrow direction) is measured, and this is referred to as “peeling weight”. The peeling weight is measured using a Tensilon universal material testing machine RTC-1250A manufactured by Orientec Co., Ltd.

[Example 1]
(1) Manufacture of release sheet A composition for forming a primer layer (EBF primer manufactured by Showa Ink Co., Ltd.) is applied to the easily adhesive surface of a PET film having a thickness of 50 μm (Cosmo Shine (registered trademark) A4100 manufactured by Toyo Spinning Co., Ltd.). Then, an ionizing radiation curable resin composition was applied thereto at an amount of 5 g / m ² (when dried), and an electron beam irradiation of 5 mad was performed at an acceleration voltage of 165 kV to obtain the ionizing radiation curable resin composition. By curing the coating film, a release sheet having a surface layer formed of a cured product of the ionizing radiation curable resin composition was produced.

The ionizing radiation curable resin composition contains 4 parts by mass of an amino-modified silane coupling agent (silane coupling agent having an amino group) with respect to 100 parts by mass of Seikabeam EB / CON (a) NS clear manufactured by Dainichiseika Kogyo Co., Ltd. It was prepared by adding a portion. As the amino-modified silane coupling agent, 3-aminopropyltriethoxysilane was used. The composition of the ionizing radiation curable resin composition is as follows, and the amount of the amino-modified silane coupling agent contained in the ionizing radiation curable resin composition is the ionizing radiation curable contained in the ionizing radiation curable resin composition. It is 4.11 parts by mass with respect to 100 parts by mass of the resin (trifunctional acrylate monomer).
-Trifunctional acrylate monomer 97.26 parts by mass-Non-reactive polymer 2.24 parts by mass-Silica fine particles (average particle size: 5 μm) 0.5 parts by mass-Amino-modified silane coupling agent 4 parts by mass

(2) Measurement of peeling weight of peeling sheet Using the gravure printing method, printing ink (Ode SPTI manufactured by DIC Graphics Co., Ltd.) is printed on the base paper, and printing with a wood grain pattern pattern layer with a thickness of 3 μm. Manufactured paper. As the base paper, white titanium paper (PM-7P manufactured by KJ Special Paper Co., Ltd.) having a basis weight of 100 g / m ² was used. The amount of ash (inorganic component) contained in the white titanium paper is 23% by mass, and the amount of ash is almost equal to the amount of titanium oxide.

An uncured melamine resin composition is impregnated into an overlay base paper having a basis weight of 42 g / m ² to which polyamide polyamine epichlorohydrin resin, carboxymethyl cellulose, sulfate band and sodium aluminate are added to α-cellulose pulp fibers. It was allowed to dry to produce a melamine resin-impregnated overlay paper. The filling rate (impregnation rate) of the uncured melamine resin composition is 142%.

The composition of the uncured melamine resin composition is as follows.
・ Uncured melamine resin (water-soluble methylol melamine resin, Nikaresin S-260 manufactured by Nippon Carbide Industries Co., Ltd.) 60 parts by mass ・ 35 parts by mass of water ・ 5 parts by mass of isopropyl alcohol

The printing paper was laminated on two sheets of phenol resin impregnated core paper (Ota core manufactured by Ota Sangyo Co., Ltd.) manufactured by impregnating kraft paper with a phenol resin solution and having a basis weight of 245 g / m ² , and further impregnated with phenol resin. A melamine resin-impregnated overlay paper was laminated on the core paper, and a release sheet was further laminated on the melamine resin-impregnated overlay paper to form a laminated body. The release sheet was laminated so that the surface layer of the release sheet was in contact with the melamine resin-impregnated overlay paper.

The formed laminate is sandwiched between two chrome-plated mirror plates on the surface of two iron plates, and heat-molded using a heat press machine under the conditions of a pressure of 195 kg / cm ² , a molding temperature of 145 ° C, and a molding time of 7 minutes. Then, the uncured melamine resin composition was heat-cured to form a cured melamine resin layer containing a cured product of the melamine resin.

The peeling weight when peeling the peeling sheet from the cured melamine resin layer was measured by the following method. A 1-inch wide notch was made in the release sheet, one end of the cut release sheet was peeled off, and then one end (lower part) of the laminated body was fixed to the testing machine. The weight when the peeling sheet peeled off by 180 ° was peeled off at a speed of 100 mm / min in the upper direction (arrow direction) was measured, and this was defined as "peeling weight". The peeling weight was measured using a Tensilon universal material testing machine RTC-1250A manufactured by Orientec Co., Ltd. The results are shown in Table 1.

[Example 2]
In Example 2, the amount of the amino-modified silane coupling agent added was changed to 6 parts by mass with respect to 100 parts by mass of Seikabeam EB CON (a) NS clear manufactured by Dainichiseika Kogyo Co., Ltd. It is the same as 1. The results are shown in Table 1. The amount of the amino-modified silane coupling agent contained in the ionizing radiation curable resin composition is 100 parts by mass of the ionizing radiation curable resin (trifunctional acrylate monomer) contained in the ionizing radiation curable resin composition. 6.17 parts by mass.

[Example 3]
In Example 3, the amount of the amino-modified silane coupling agent added was changed to 8 parts by mass with respect to 100 parts by mass of Seikabeam EB CON (a) NS clear manufactured by Dainichiseika Kogyo Co., Ltd. It is the same as 1. The results are shown in Table 1. The amount of the amino-modified silane coupling agent contained in the ionizing radiation curable resin composition is 100 parts by mass of the ionizing radiation curable resin (trifunctional acrylate monomer) contained in the ionizing radiation curable resin composition. 8.23 parts by mass.

[Comparative Example 1]
Comparative Example 1 is the same as that of Example 1 except that the amino-modified silane coupling agent was not added. The results are shown in Table 1.

Although the release layer is not provided in Examples and Comparative Examples, the release weight of the release sheet, which is an index of the bonding strength between the surface layer of the release sheet and the cured melamine resin layer, is more sufficient than that of Comparative Example 1. If it is large, it is preferably 1 N / inch or more, more preferably 1.5 N / inch or more, and even more preferably 2 N / inch or more, when the release layer is provided, the part to be peeled off (cured melamine). It is known that the portion of the resin layer that covers the release layer) can be sufficiently peeled off.

[Comparative Example 2]
In Comparative Example 2, the amount of the amino-modified silane coupling agent added was changed to 1 part by mass with respect to 100 parts by mass of Seikabeam EB ・ CON (a) NS clear manufactured by Dainichiseika Kogyo Co., Ltd. It is the same as 1. The results are shown in Table 1. The amount of the amino-modified silane coupling agent contained in the ionizing radiation curable resin composition is 100 parts by mass of the ionizing radiation curable resin (trifunctional acrylate monomer) contained in the ionizing radiation curable resin composition. It is 1.03 parts by mass.

[Comparative Example 3]
In Comparative Example 3, the amount of the amino-modified silane coupling agent added was changed to 2 parts by mass with respect to 100 parts by mass of Seikabeam EB / CON (a) NS clear manufactured by Dainichiseika Kogyo Co., Ltd. It is the same as 1. The results are shown in Table 1. The amount of the amino-modified silane coupling agent contained in the ionizing radiation curable resin composition is 100 parts by mass of the ionizing radiation curable resin (trifunctional acrylate monomer) contained in the ionizing radiation curable resin composition. 2.06 parts by mass.

[Comparative Example 4]
In Comparative Example 4 , the amount of the amino-modified silane coupling agent added was changed to 10 parts by mass with respect to 100 parts by mass of Seikabeam EB / CON (a) NS clear manufactured by Dainichiseika Kogyo Co., Ltd. It is the same as 1. The results are shown in Table 1. The amount of the amino-modified silane coupling agent contained in the ionizing radiation curable resin composition is 100 parts by mass of the ionizing radiation curable resin (trifunctional acrylate monomer) contained in the ionizing radiation curable resin composition. 10.28 parts by mass.

[Comparative Example 5]
In Comparative Example 5, instead of the amino-modified silane coupling agent, an acrylic-modified silane coupling agent (3-acryloxypropyltrimethoxysilane) was used in Seikabeam EB ・ CON (a) NS Clear 100 manufactured by Dainichiseika Kogyo Co., Ltd. It is the same as in Example 1 except that it is added in an amount of 1, 2 or 10 parts by mass with respect to parts by mass. The results are shown in Table 1. The amount of the acrylic-modified silane coupling agent contained in the ionizing radiation curable resin composition is 100 parts by mass of the ionizing radiation curable resin (trifunctional acrylate monomer) contained in the ionizing radiation curable resin composition. It is 1.03, 2.06 or 10.28 parts by mass.

[Comparative Example 6]
In Comparative Example 6 , instead of the amino-modified silane coupling agent, a mercapto-modified silane coupling agent (3-mercaptopropyltrimethoxysilane) was used, and Seikabeam EB ・ CON (a) NS clear 100 mass manufactured by Dainichiseika Kogyo Co., Ltd. It is the same as in Example 1 except that it is added in an amount of 1, 2 or 10 parts by mass with respect to the part. The results are shown in Table 1. The amount of the mercapto-modified silane coupling agent contained in the ionizing radiation curable resin composition is 100 parts by mass of the ionizing radiation curable resin (trifunctional acrylate monomer) contained in the ionizing radiation curable resin composition. It is 1.03, 2.06 or 10.28 parts by mass.

10 ... Release sheet 11 ... Base sheet 12 ... Surface layer 13 ... Primer layer 20 ... Decorative plate 21 ... Support layer 22 ... Demolding layer 23 ... Hardened melamine Resin layer 24 ... Core layer 25 ... Recess S10 ... First surface T10 of the release sheet ... Second surface S20 of the release sheet ... First surface T20 of the decorative board ... Of the decorative board Second surface S21 ... First surface of the support layer T21 ... Second surface of the support layer S22 ... Surface of the release layer S23 ... Surface of the cured melamine resin layer

Claims (7)

A release sheet having a first surface and a second surface located on the opposite side of the first surface.
The release sheet comprises a base material sheet and a surface layer forming the first surface of the release sheet.
The surface layer has one or more ionizing radiation curable properties selected from a (meth) acrylate monomer having a radically polymerizable unsaturated group in the molecule and a (meth) acrylate oligomer having a radically polymerizable unsaturated group in the molecule . It is formed of a cured product of an ionizing radiation curable resin composition containing a resin and a silane coupling agent having an amino radical.
The release sheet in which 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 with respect to 100 parts by mass of the ionizing radiation curable resin. The peeling according to claim 1, wherein the ionizing radiation curable resin composition contains a polyfunctional monomer of 80% by mass or more and 97% by mass or less based on the total solid content of the ionizing radiation curable resin composition. Sheet. The release sheet according to claim 1 or 2, further comprising a primer layer provided between the base material sheet and the surface layer. A method for manufacturing a decorative board using the release sheet according to any one of claims 1 to 3.
(1) A support layer having a first surface and a second surface located on the opposite side of the first surface, a mold release layer provided on a part of the first surface of the support layer, and a first of the support layers. The uncured melamine resin layer covering the rest of one surface and the release layer, and the uncured melamine resin layer provided on the uncured melamine resin layer so that the first surface of the release sheet is in contact with the uncured melamine resin layer. A step of preparing a laminate including a release sheet and a precursor layer of a core layer provided on the second surface of the support layer.
(2) A step of curing the uncured melamine resin layer by pressurizing and heating the laminate to form a cured melamine resin layer, and
(3) By peeling off the release sheet, the portion of the cured melamine resin layer that covers the release layer is peeled off, and the cured melamine resin layer is provided with an opening that exposes the surface of the release layer. The method comprising the step of forming. The method according to claim 4, wherein the support layer has a paper-like substrate. The method of claim 5, wherein the support layer further comprises a decorative layer provided on the paper substrate. The laminate prepared in the step (1) contains an uncured melamine resin filled in the voids of the paper substrate, and contains the uncured material.
In the step (2), the laminated body is pressurized and heated to cure the uncured melamine resin filled in the voids of the paper substrate together with the uncured melamine resin layer, and the paper substrate is cured. The method according to claim 5 or 6, wherein the cured product of the melamine resin filled in the voids of No. 5 and the cured product of the melamine resin contained in the cured melamine resin layer are integrated.

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