Active energy ray curable primer composition, decorative sheet for building materials using the same, and method for producing the same

Abstract

To provide a one liquid-type primer composition for making an EB-curable coating agent containing a delustering agent such as silica adhere with an olefin substrate, a decorative sheet for a housing material using the same, and a production method of the same.SOLUTION: A solution means of the present invention has been found that an active energy ray-curable primer composition containing a compound having a (meth)acryloyl group, and having a specific range of (meth)acryloyl group equivalent solves a problem. The active energy-curable primer composition contains a compound having a (meth)acryloyl group, and has a range of methacryloyl group equivalent of 80-750 g / eq.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an active energy ray-curable primer composition which is applied to a primer layer provided between a substrate sheet made of a polyolefin resin and an electron beam-curable coating agent containing a matting agent. [Background technology]

[0002] It is generally known that, for aesthetic purposes, etc., an electron beam curable (sometimes called EB curable) or ultraviolet ray curable (sometimes called UV curable) coating agent is applied to a substrate (sometimes called an olefin substrate) made of a polyolefin resin, and it is also known that the presence of an acrylic monomer increases adhesion to the olefin substrate by EB irradiation (see, for example, Patent Document 1).

[0003] As a specific example of applying an EB-cured coating agent to an olefin substrate for the purpose of aesthetics, etc., a flooring material is known in which a tissue paper with a patterned layer is pasted onto a wood substrate such as lauan plywood and then painted. However, in the case of flooring materials, a matting agent such as silica is often added to the EB-cured or UV-cured coating agent applied to the olefin substrate for the purpose of preventing slippage and matting, which is a factor in reducing adhesion to the olefin substrate. In addition, in order to obtain a floor decorative material with a sense of depth, it is also required to increase the thickness of the coating film formed on the floor decorative material, but when the thickness of the coating film is increased, there is also a problem that a higher coating film adhesion is required on the coating film forming surface of the floor decorative sheet.

[0004] For the purpose of achieving higher coating film adhesion to the coating film-forming surface of the floor decorative sheet, Patent Document 2 describes a method for producing a floor decorative material having, in this order, a substrate sheet made of a polyolefin resin, a pattern layer, etc., a coating film-forming primer layer formed of an acrylic-urethane copolymer resin and an isocyanate, and a coating film that is mainly a urethane acrylate-based electron beam curable resin layer on an olefin adherend. This allows a floor decorative material to be obtained that has excellent adhesion to the substrate even if the coating film thickness is 50 μm. However, since the isocyanate-curable primer is essentially a two-liquid type and has a fast curing speed, there are problems that the application is complicated because it must be mixed immediately before application and applied before curing, and problems that need to be improved, such as the need for a certain period of aging. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2001-181317 A [Patent Document 2] JP 2015-34462 A Summary of the Invention [Problem to be solved by the invention]

[0006] The problem that the present invention aims to solve is to provide a one-liquid type primer composition for adhering an EB-curable coating agent containing a matting agent such as silica to an olefin substrate, and to provide a decorative sheet for building materials using said primer composition and a method for producing the same. [Means for solving the problem]

[0007] The present inventors have found that an active energy ray-curable primer composition containing a compound having a (meth)acryloyl group and having a (meth)acryloyl group equivalent within a specific range can solve the above problems.

[0008] That is, the present invention provides an active energy ray-curable primer composition which contains a compound having a (meth)acryloyl group and has a (meth)acryloyl group equivalent in the range of 80 to 750 g / eq.

[0009] The present invention also provides a decorative sheet for building materials, comprising at least a primer layer and a coating layer formed in this order on a substrate sheet made of a polyolefin resin, the primer layer being a cured product of the active energy ray-curable primer composition described above, The decorative sheet for building materials is provided, wherein the coating layer is a cured product of an electron beam-curable coating composition containing a matting agent.

[0010] The present invention also relates to a method for producing a coating layer (A) of an active energy ray-curable primer composition, which contains a compound having a (meth)acryloyl group and has a (meth)acryloyl group equivalent in the range of 80 to 750 g / eq., on a substrate sheet made of a polyolefin resin; Step 2 of forming a coating layer (B) of an electron beam curable coating composition containing a matting agent on the coating layer (A); and step 3 of irradiating the surface layer side of the coating layer (B) with an electron beam. A method for producing a decorative sheet for building materials having the following in this order: The present invention provides a method for producing a decorative sheet for building materials, wherein the (meth)acryloyl group equivalent of the primer composition in step 1 and the electron beam irradiation dose (Y)kGy in step 3 satisfy the relationship of (absolute value of the (meth)acryloyl group equivalent) / (absolute value of (Y)kGy<10. Effect of the Invention

[0011] The active energy ray-curable primer composition of the present invention can improve adhesion between an EB-curable coating agent containing a matting agent such as silica and an olefin substrate, and has good adhesion to the olefin substrate. In particular, according to the manufacturing method of the decorative sheet for building materials of the present invention, a decorative sheet for building materials having excellent adhesion between each layer can be obtained. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] (Active energy ray curable primer composition) The active energy ray-curable primer composition of the present invention is characterized in that it contains a compound having a (meth)acryloyl group and has a (meth)acryloyl group equivalent in the range of 80 to 750 g / eq. In the present invention, the term "(meth)acryloyl group" refers to either or both of an acryloyl group and a methacryloyl group. In addition, a "compound having a (meth)acryloyl group" may be referred to as a (meth)acrylate. "(Meth)acrylate" refers to either or both of an acrylate and a methacrylate.

[0013] (Compound having a (meth)acryloyl group) The compound having a (meth)acryloyl group used in the present invention is not particularly limited, and any known compound having a (meth)acryloyl group that can be cured by active energy rays can be used. Examples of monofunctional (meth)acrylates include ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, hexadecyl (meth)acrylate, octadecyl (meth)acrylate, isoamyl (meth)acrylate, isodecyl (meth)acrylate, isostearyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, methoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, nonyl Examples of the acrylates include phenoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, glycidyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, diethylaminoethyl (meth)acrylate, nonylphenoxyethyl tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and ethoxyethoxyethanol acrylic acid polymer ester.

[0014] Examples of bifunctional (meth)acrylates include 1,4-butanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 2-methyl-1,8-octanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropionyl ... Examples of the di(meth)acrylate include dihydric alcohol di(meth)acrylates such as ethylene glycol di(meth)acrylate and tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, di(meth)acrylate of tris(2-hydroxyethyl)isocyanurate, di(meth)acrylates of diols obtained by adding 4 or more moles of ethylene oxide or propylene oxide to 1 mole of neopentyl glycol, and di(meth)acrylates of diols obtained by adding 2 moles of ethylene oxide or propylene oxide to 1 mole of bisphenol A.

[0015] Examples of the trifunctional or higher (meth)acrylate include poly(meth)acrylates of trivalent or higher polyhydric alcohols such as trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and dipentaerythritol poly(meth)acrylate; poly(meth)acrylates of polyoxyalkylene polyols such as triol tri(meth)acrylates obtained by adding 3 moles or more of ethylene oxide or propylene oxide to 1 mole of glycerin, triol di- or tri(meth)acrylates obtained by adding 3 moles or more of ethylene oxide or propylene oxide to 1 mole of trimethylolpropane, and di(meth)acrylates of diols obtained by adding 4 moles or more of ethylene oxide or propylene oxide to 1 mole of bisphenol A.

[0016] Furthermore, a mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (sometimes abbreviated as DPHA), which are bifunctional or higher (meth)acrylates, ditrimethylolpropane tetraacrylate (sometimes abbreviated as DTMPTA), trimethylolpropane ethylene oxide adduct tri(meth)acrylate, which is a triol tri(meth)acrylate obtained by adding 3 moles or more of ethylene oxide to 1 mole of trimethylolpropane, etc. may be used. A representative example of the trimethylolpropane ethylene oxide adduct tri(meth)acrylate is trimethylolpropane ethylene oxide (hereinafter, ethylene oxide may be referred to as "EO") modified (n≒3) triacrylate. The total amount of the monofunctional (meth)acrylate and di- or higher functional (meth)methacrylate is preferably in the range of 60 to 80 mass %, more preferably 65 to 75 mass %, of the total amount of the curable components in the coating agent.

[0017] Furthermore, a polymerizable oligomer may be used as necessary. Examples of the polymerizable oligomer include urethane (meth)acrylate, amine-modified polyether acrylate, amine-modified epoxy acrylate, amine-modified aliphatic acrylate, amine-modified polyester acrylate, amine-modified acrylate such as amino (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, polyolefin (meth)acrylate, polystyrene (meth)acrylate, and epoxy (meth)acrylate.

[0018] Among the compounds having a (meth)acryloyl group, phenol EO-modified acrylate, EO-modified 1,6-hexanediol diacrylate, EO-modified bisphenol A diacrylate, EO-modified trimethylolpropane triacrylate, and pentaerythritol alkoxytetraacrylate are preferred, and 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, trimethylolpropane tri(meth)acrylate, and DPHA are more preferred.

[0019] In the active energy ray-curable primer composition of the present invention, the (meth)acryloyl group equivalent is represented by the formula (1), where the unit is g / eq.

[0020]

number

[0021] In formula (1), the total weight of non-volatile components refers to the total weight of non-volatile components contained in the active energy ray-curable primer composition of the present invention. For example, organic solvents are volatile components, and compounds having (meth)acryloyl groups and silica are non-volatile components.

[0022] In addition, in formula (1), "Σ((weight [g] of compound having a (meth)acryloyl group) / ((meth)acryloyl group equivalent [eq] of compound having a (meth)acryloyl group))" represents the sum of the weight [g] of the compound having a (meth)acryloyl group, of a plurality of compounds having a (meth)acryloyl group contained in the active energy ray-curable primer composition of the present invention, divided by the (meth)acryloyl group equivalent [g / eq.] of the compound having a (meth)acryloyl group, and the value of all the compounds having a (meth)acryloyl group is calculated.

[0023] The (meth)acryloyl group equivalent [g / eq.] of a compound having a (meth)acryloyl group can be calculated by "weight average molecular weight of the compound having a (meth)acryloyl group / number of (meth)acryloyl groups per molecule of the compound having a (meth)acryloyl group" when the weight average molecular weight and number of (meth)acryloyl groups per molecule are clear, such as in the case of a monomer. On the other hand, when the weight average molecular weight and number of (meth)acryloyl groups per molecule are not clear, such as in the case of a polymer or oligomer (such as acrylic acrylate), it can be calculated from the amount charged during synthesis using the formula "weight of all monomers constituting the polymer [g] / amount of acrylic acid charged [mol]".

[0024] For example, when the active energy ray-curable primer composition of the present invention is composed only of dipentaerythritol hexaacrylate (weight average molecular weight: 524), which is a hexafunctional (meth)acrylate, the (meth)acryloyl group equivalent is 87 [g / eq.]. Furthermore, for example, when the active energy ray-curable primer composition of the present invention is composed only of the polymerizable oligomer acrylic acrylate "Luxidia CH-S-1371 (manufactured by DIC Corporation)", the (meth)acryloyl group equivalent is calculated to be 750 [g / eq.] from the charged amount. In addition, for example, when the active energy ray-curable primer composition of the present invention contains 30% by weight of dipentaerythritol hexaacrylate (weight average molecular weight 524) which is a hexafunctional (meth)acrylate, 67.5% by weight of Miramer M3130 (manufactured by MIWON Co., Ltd.) (weight average molecular weight 429) which is a trifunctional (meth)acrylate, and 2.8% by weight of a photopolymerization initiator, the (meth)acryloyl group equivalent is (30+67.5+2.8) / ((30 / 87)+(67.2 / 143))=100 / (0.34+0.47))=122.7[g / eq.].

[0025] In the present invention, the (meth)acryloyl group equivalent calculated by the above formula (1) is preferably in the range of 80 to 750 g / eq., more preferably in the range of 80 to 500 g / eq., and most preferably in the range of 80 to 250 g / eq.

[0026] The compound having a (meth)acryloyl group is preferably contained in an amount of 50 to 100% by mass based on the solid content of the active energy ray-curable primer composition.

[0027] (Photopolymerization initiator) The active energy ray curable primer composition of the present invention does not require a photopolymerization initiator or the like because it is cured by an electron beam, but in the manufacturing method of the decorative sheet for building materials of the present invention described later, when ultraviolet irradiation is performed for the purpose of drying (tack-free) only the surface of the coating layer (A) after step 1 of forming the coating layer (A) of the primer composition, a photopolymerization initiator or the like can be added. As the photopolymerization initiator used in this case, a known one may be used.

[0028] Among them, radical polymerization type photopolymerization initiators are preferred, and α-hydroxyalkyl ketone-based photopolymerization initiators are preferred, which do not color the solution when the active energy ray curable compound is dissolved and do not yellow over time. Examples of α-hydroxyalkyl ketone-based photopolymerization initiators include 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1-(4-i-propylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, and 1-hydroxycyclohexyl phenyl ketone. Furthermore, phenylglyoxolate-based photopolymerization initiators are also preferred. Examples of phenylglyoxolate-based photopolymerization initiators include methylbenzoyl formate. Among them, 1-hydroxycyclohexyl phenyl ketone is preferred.

[0029] As other radical polymerization type photopolymerization initiators, monoacylphosphine oxide-based photopolymerization initiators having an absorption wavelength in the long wavelength region of ultraviolet light may be used in appropriate combination. Examples of the monoacylphosphine oxide photopolymerization initiator include monoacylphosphine oxides such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,6-dimethoxybenzoyl-diphenylphosphine oxide, 2,6-dichlorobenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-phenylphosphine acid methyl ester, 2-methylbenzoyl-diphenylphosphine oxide, and pivaloylphenylphosphine acid isopropyl ester, excluding bisacylphosphine oxides that become colored when dissolved in an active energy ray-curable compound. Among these, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide is particularly preferred in that it has a UV absorption wavelength that matches the emission wavelength region of UV-LEDs having an emission wavelength of 385 nm or 395 nm, thereby obtaining suitable curability and causing less yellowing of the cured film.

[0030] The photopolymerization initiators described above may be used alone or in combination of two or more. The total amount of the photopolymerization initiators added is preferably in the range of 0.1 to 20% by mass based on the total amount of the coating agent. If it is 0.1% by mass or more, good curing properties can be obtained, and if it is 20% by mass or less, the amount of initiator does not become excessive, and the fluidity of the coating agent can be maintained, and processability and workability are not reduced.

[0031] Furthermore, the curing speed can be increased by adding a tertiary amine compound selected from aliphatic amine derivatives and / or benzoic acid amine derivatives as a sensitizer. Tertiary amine compounds are known to increase reactivity and prevent reaction inhibition by oxygen. Suitable tertiary amine compounds include free alkylamines such as triethylamine, methyldiethanolamine, and triethanolamine, aromatic amines such as 2-ethylhexyl-4-dimethylaminobenzoate and ethyl-4-dimethylaminobenzoate, and active energy ray polymerizable compounds such as polymeric unsaturated amines (e.g., (meth)acrylated amines), which are considered to be preferred due to their low odor, low volatility, and ability to be incorporated into the polymer matrix by curing, thereby suppressing yellowing.

[0032] The tertiary amine compound can be used in an amount of preferably 0.1 to 10% by mass, more preferably 0.3 to 3% by mass, based on the total amount of the coating material including the organic solvent.

[0033] (Organic solvent) In addition, in the manufacturing method of the decorative sheet for building materials of the present invention described below, in step 1 of forming the coating layer (A) of the primer composition, an organic solvent can be added to the active energy ray-curable primer composition of the present invention as a diluent to facilitate coating. Any organic solvent can be used as long as it dissolves the compound having a (meth)acryloyl group used, but it is more preferable that the organic solvent does not contain highly volatile organic compounds (VVOCs) having a boiling point of 50°C or less under normal pressure or volatile organic compounds (VOCs) having a boiling point of 50 to 260°C. The purpose is to thoroughly reduce the amount of organic solvents evaporated into the atmosphere, i.e., to reduce VOCs, and it is preferable that the solvent does not contain any of the following organic solvents: aromatic hydrocarbons such as toluene and xylene; aliphatic or alicyclic hydrocarbons such as n-hexane, cyclohexane, methylcyclohexane and ethylcyclohexane; esters such as ethyl acetate, butyl acetate and propyl acetate; alcohols such as methanol, ethanol, isopropyl alcohol and n-butanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; alkylene glycol monoalkyl ethers such as ethylene glycol monoethyl ether and propylene glycol monomethyl ether; and ether esters such as propylene glycol monomethyl ether acetate.

[0034] From the viewpoint of coatability, the active energy ray-curable primer composition of the present invention is preferably adjusted to a viscosity that allows coating in the manufacturing method of the decorative sheet for building materials of the present invention described below. The viscosity is preferably adjusted to 1 to 3000 mPa·s. The compounds having the (meth)acryloyl group generally have low molecular weights, and if the viscosity can be adjusted without dilution with an organic solvent, there is no need to dilute with an organic solvent. On the other hand, when a polymerizable oligomer or polymerizable polymer having a high molecular weight and high viscosity is used in combination, the viscosity can be adjusted by diluting with an organic solvent.

[0035] In order to exhibit adhesion to a polyolefin substrate sheet, the active energy ray curable primer composition of the present invention preferably does not contain solid fine particles. Here, the solid fine particles refer to fine particles that are solid at room temperature and have a particle size of 30 μm or less. Specific examples include matting agents, antiblocking agents, etc.

[0036] In addition, the active energy ray-curable primer composition of the present invention may contain a matting agent, a polymerization inhibitor, a leveling agent, a thixotropy imparting agent, a wax, a drying agent, a thickening agent, an anti-sagging agent, a plasticizer, a dispersant, an anti-settling agent, an antifoaming agent, an ultraviolet absorber, a light stabilizer, and the like.

[0037] (Decorative sheet for building materials) The decorative sheet for building materials of the present invention is a decorative sheet for building materials comprising at least a primer layer and a coating layer formed in this order on a substrate sheet made of a polyolefin resin, The primer layer is a cured product of the above-described active energy ray-curable primer composition, and the coating layer is a cured product of an electron beam-curable coating composition containing a matting agent.

[0038] (Base sheet made of polyolefin resin) In the base sheet made of polyolefin resin used in the present invention, the polyolefin resin is not particularly limited, and those usually used in the field of decorative sheets can be used. For example, polyethylene, polypropylene, polybutene, polymethylpentene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-propylene-butene copolymer, polyolefin thermoplastic elastomer, etc. are mentioned. Among these, polypropylene, polyolefin thermoplastic elastomer, etc. are particularly preferred.

[0039] The polyolefin resin can be used after being molded into a film shape by, for example, a calendar method, an inflation method, a T-die extrusion method, etc. The thickness of the base sheet is not particularly limited and can be set according to the product characteristics, but is usually about 40 to 150 μm, and preferably about 50 to 100 μm.

[0040] The base sheet may contain additives as necessary. Examples of additives include fillers such as calcium carbonate and clay, flame retardants such as magnesium hydroxide, antioxidants, lubricants, foaming agents, colorants, etc. The amount of additives to be added can be appropriately determined depending on the product characteristics.

[0041] One or both sides of the base sheet may be subjected to a surface treatment such as corona discharge treatment, ozone treatment, plasma treatment, ionizing radiation treatment, dichromate treatment, etc. For example, when corona discharge treatment is performed, the surface tension of the base sheet surface may be set to 30 dyne or more, preferably 40 dyne or more. The surface treatment may be performed according to a conventional method for each treatment.

[0042] (Electron beam curable coating composition containing a matting agent) The electron beam curable coating composition containing a matting agent used in the present invention contains a matting agent and a compound having a (meth)acryloyl group. As the compound having a (meth)acryloyl group, the same compounds as those in the above-mentioned active energy ray-curable primer composition of the present invention can be used.

[0043] Examples of the matting agent include inorganic fillers selected from silica, clay, heavy calcium carbonate, light calcium carbonate, precipitated barium sulfate, calcium silicate, synthetic silicate, and silicic acid fine powder, and organic fillers or resin beads selected from acrylic resins, urethane resins, nylon resins, polypropylene resins, and urea resins. Any one of these may be used alone or two or more of them may be used in combination.

[0044] The volume average particle diameter of the matting agent is not particularly limited, but is generally 0.5 to 25 μm, more preferably 1 to 15 μm, and further preferably 3 to 10 μm. From the viewpoint of matting effect, it is preferable that the volume average particle diameter of the matting agent is 0.5 μm or more. The volume average particle diameter referred to here is the particle diameter at an integrated value of 50% in the particle size distribution obtained by the laser diffraction-scattering method. The content of the matting agent is preferably from 0.5 to 50% by mass, more preferably from 10 to 50% by mass, and further preferably from 25 to 50% by mass.

[0045] The electron beam curable coating composition may contain other additives, such as a leveling agent, a thixotropy imparting agent, a wax, a drying agent, a thickener, an anti-sagging agent, a plasticizer, a dispersant, an anti-settling agent, an antifoaming agent, an ultraviolet absorbing agent, a light stabilizer, and a release agent, as necessary.

[0046] The decorative sheet for building materials of the present invention may have, in addition to the primer layer and the coating layer, an easy-adhesion layer, a picture pattern layer, a transparent adhesive layer, and a transparent resin layer, which are usually provided on decorative sheets for building materials.

[0047] The easy-adhesion layer is provided on the surface of the substrate sheet made of a polyolefin resin opposite to the surface on which the primer layer or coating layer is provided, for the purpose of enhancing adhesion to a wood substrate such as lauan plywood, etc. For example, an easy-adhesion layer made of a thermoplastic resin such as a polyamide resin, an acrylic resin, or a vinyl acetate resin can be used.

[0048] The picture pattern layer imparts design to the decorative sheet with a desired pattern, and the type of pattern is not particularly limited. Examples include wood grain, stone grain, sand grain, tiled pattern, brickwork pattern, cloth pattern, leather pattern, geometric figures, letters, symbols, abstract patterns, etc. The method of forming the picture pattern layer is not particularly limited, and it may be formed, for example, by a printing method using a colored ink, coating agent, etc. obtained by dissolving (or dispersing) a known colorant (dye or pigment) together with a binder resin in a solvent (or dispersion medium). The pattern printed layer is usually provided on a separate sheet by a known printing method such as gravure printing, offset printing, screen printing, flexographic printing, electrostatic printing, inkjet printing, etc., and is attached to a base sheet made of a polyolefin resin via a transparent adhesive layer described below.

[0049] The transparent adhesive layer is not particularly limited as long as it is transparent, and includes colorless transparent, colored transparent, translucent, etc. The adhesive is not particularly limited, and adhesives known in the field of decorative sheets, such as thermoplastic resins such as polyamide resins, acrylic resins, and vinyl acetate resins, curable resins such as thermosetting urethane resins, and adhesives such as two-component curing polyurethane resins or polyester resins using isocyanate as a curing agent, can be used.

[0050] In addition, a transparent resin layer can be provided separately for the purpose of imparting visibility and various strengths as a flooring material. The transparent resin layer includes any of colorless transparent, colored transparent, translucent, etc., as long as it is transparent. The resin component contained in the transparent resin layer is not limited, but is preferably a thermoplastic resin, and particularly preferably polypropylene. In addition, additives such as fillers, flame retardants, lubricants, antioxidants, and light stabilizers (ultraviolet absorbers, radical scavengers, etc.) can be added depending on the physical properties desired for the flooring material. In particular, the addition of a light stabilizer is preferable to improve weather resistance.

[0051] (Method of manufacturing decorative sheets for building materials) The method for producing the decorative sheet for building materials of the present invention includes a step 1 of forming a coating layer (A) of an active energy ray-curable primer composition containing a compound having a (meth)acryloyl group and having a (meth)acryloyl group equivalent in the range of 80 to 750 g / eq. on a substrate sheet made of a polyolefin resin; Step 2 of forming a coating layer (B) of an electron beam curable coating composition containing a matting agent on the coating layer (A); and step 3 of irradiating the surface layer side of the coating layer (B) with an electron beam. A method for producing a decorative sheet for building materials having the following in this order: The (meth)acryloyl group equivalent of the primer composition in step 1 and the electron beam irradiation dose (Y)kGy in step 3 satisfy the relationship of absolute value of the (meth)acryloyl group equivalent / absolute value of (Y)kGy<10.

[0052] (Process 1) Step 1 is a step of forming a coating layer (A) of the active energy ray-curable primer composition of the present invention on a substrate sheet made of a polyolefin resin. The method for forming the coating layer (A) on the substrate sheet made of a polyolefin resin is not particularly limited, and any known coating or printing method may be used. Specific examples of the coating layer (A) include roll coaters, gravure coaters, flexo coaters, air doctor coaters, blade coaters, air knife coaters, squeeze coaters, impregnation coaters, transfer roll coaters, kiss coaters, curtain coaters, cast coaters, spray coaters, die coaters, offset printers, and screen printers. Among these, gravure coaters are preferred.

[0053] From the viewpoint of processability, the thickness of the coating layer (A) is preferably from 0.1 to 10 μm, and more preferably from 0.5 to 5.0 μm.

[0054] The coating layer (A) obtained in step 1 is an uncured layer of the active energy ray-curable primer composition of the present invention, and therefore the surface will not dry if left as is, which may cause problems depending on the actual production line. As mentioned above, from the viewpoint of coatability, the active energy ray curable primer composition of the present invention is adjusted to a viscosity that can be applied in the manufacturing method of the decorative sheet for building materials of the present invention described later, but when it is diluted with an organic solvent as an adjustment method, it may become tack-free just by drying the organic solvent. On the other hand, in the case of a primer composition that is composed only of a compound having a low molecular weight (meth)acryloyl group and is not diluted with an organic solvent, the surface does not dry as it is, so it is preferable to cure only the surface (to become tack-free) with active energy rays to an extent that the primer composition does not fully cure.

[0055] The active energy rays include ionizing radiation and electromagnetic waves such as ultraviolet rays, electron beams, and gamma rays, and among these, ultraviolet rays are preferred. When ultraviolet rays are used as the active energy rays, it is preferable to add a photopolymerization initiator to the primer composition in advance. When irradiating with ultraviolet rays, a known ultraviolet ray irradiation device equipped with a high-pressure mercury lamp, an excimer lamp, a metal halide lamp, or the like can be used. The amount of ultraviolet light in this case is 10 to 300 mJ / cm. 2 The range is preferably 20 to 100 mJ / cm 2 The range is more preferable.

[0056] (Process 2) On the coating layer (A) obtained in the above step 1, a coating layer (B) of an electron beam curable coating composition containing a matting agent is formed. The coating method for the coating layer (B) is similar to the coating method in step 1, and the method for forming the coating layer (A) on the substrate sheet made of a polyolefin resin is not particularly limited, and any known coating or printing method may be used. Specific examples of the coating layer (A) include roll coaters, gravure coaters, flexo coaters, air doctor coaters, blade coaters, air knife coaters, squeeze coaters, impregnation coaters, transfer roll coaters, kiss coaters, curtain coaters, cast coaters, spray coaters, die coaters, offset printers, and screen printers. Among these, gravure coaters are preferred.

[0057] From the viewpoints of processability and surface physical properties, the thickness of the coating layer (B) is preferably from 5.0 to 40 μm, and more preferably from 5.0 to 15 μm.

[0058] From the viewpoints of processability and surface physical properties, the film thickness after lamination of coating layer (A) and coating layer (B) is preferably 5 to 100 μm, and more preferably 5 to 50 μm.

[0059] (Step 3) The surface side of the coating layer (B) obtained in the above step 2 is irradiated with an electron beam. The electron beam source used in this case may be the above-mentioned electron beam irradiation device. On the other hand, the energy of the electron beam in step 3 is preferably about 100 to 250 kV, more preferably about 125 to 175 kV, for the purpose of chemically bonding the (meth)acryloyl group of the compound having a (meth)acryloyl group in the coating layer (A), i.e., the primer composition, to the olefin substrate. The irradiation dose is preferably about 10 to 230 kGy, more preferably about 10 to 100 kGy.

[0060] The (meth)acryloyl group equivalent of the primer composition in the step 1 and the electron beam irradiation dose (Y) kGy in the step 3 are,

[0061]

number

[0062] It is characterized by satisfying the following relationship. Here, “absolute value of the (meth)acryloyl group equivalent of the primer composition / absolute value of (Y)kGy<10” means that the absolute value of the (meth)acryloyl group equivalent of the active energy ray-curable primer composition of the present invention used in step 1 is divided by the absolute value of the electron beam irradiation dose (Y)kGy in step 3, and the value is less than 10.

[0063] In the active energy ray-curable primer composition of the present invention, the smaller the (meth)acryloyl group equivalent, the larger the proportion of double bonds in one molecule, and the higher the reactivity. That is, even if the irradiation dose is small, the (meth)acryloyl group of the compound having a (meth)acryloyl group in the primer composition is easily chemically bonded to the olefin substrate. Conversely, when the (meth)acryloyl group equivalent of the active energy ray-curable primer composition is large, the reactivity is poor, and therefore, in order to chemically bond the (meth)acryloyl group of the compound having a (meth)acryloyl group in the primer composition to the olefin substrate, it is necessary to increase the irradiation dose.

[0064] The standard of the amount of irradiation sufficient to chemically bond an olefin substrate to the (meth)acryloyl group of the compound having a (meth)acryloyl group in the active energy ray-curable primer composition of the present invention is the value shown by the formula of the absolute value of the (meth)acryloyl group equivalent / the absolute value of (Y)kGy, and sufficient substrate adhesion can be obtained if this is less than 10. If this is less than 5, better substrate adhesion can be obtained. EXAMPLES

[0065] The present invention will be described in more detail below with reference to examples. In the examples, "parts" and "parts by mass" refer to mass %.

[0066] [Examples 1 to 7 (Table 1), Comparative Examples 1 to 3 (Table 2)] The primer composition prepared by mixing the components shown in Tables 1 and 2 (formulation of coating layer (A)) was applied to the surface-treated or untreated surface of a polypropylene film (Okamoto's "Basic Color PP Sheet White", 0.4 mm thick) using a bar coater #6 to form a coating layer (A). Next, a UV irradiation device (GS Yuasa Corporation) equipped with an air-cooled high-pressure mercury lamp (output 120 W / cm1 lamp) and a belt conveyor was used, and the coated material was placed on the conveyor and passed directly under the lamp (irradiation distance 15 cm) at a speed of 25 m / min for an arbitrary number of times to make the coating layer (A) tack-free. The integrated light amount at which the coating layer became tack-free is shown in Tables 1 and 2. In the primer composition formulations of Examples 4 and 7 and Comparative Examples 2 and 3, the tack-free state was achieved by drying the organic solvent, so only drying was performed and no UV irradiation was performed. Next, the components shown in Tables 1 and 2 (formulation of coating layer (B)) were mixed and prepared to prepare an electron beam curable coating composition, which was applied onto the coating layer (A) using a bar coater #6 to form the coating layer (B). Next, the coating layer (B) and the coating layer (A) were cured by irradiating them with electron beams under the conditions shown in Tables 1 and 2 using a curtain-type electron beam irradiation device ("Electrocurtain EC250 / 15 / 180L" manufactured by Iwasaki Electric Co., Ltd.).

[0067] [Evaluation method] The evaluation method of the decorative sheet for building materials of the present invention will be described below.

[0068] [Evaluation item 1: Initial adhesion] After curing, cellophane tape was applied to the surface of each of the prepared decorative sheets, which was then quickly peeled off, and the appearance of the printed coating was evaluated on the following five-point scale. The test was carried out immediately after curing. (Evaluation Criteria) ◯: No peeling of the printed coating was observed. ◯△: 70% or more of the printed coating remained on the decorative sheet substrate in terms of area ratio. △: 50% or more and less than 70% of the printed coating remained on the decorative sheet substrate in terms of area ratio. Δ×: 10% or more and less than 50% of the printed coating remained on the decorative sheet substrate in terms of area ratio. ×: Less than 10% of the printed coating remained on the decorative sheet substrate in terms of area ratio.

[0069] [Evaluation item 2: Cross-cut adhesion] After curing, shallow cross cuts were made on the surface of each decorative sheet so as to damage only the coating, cellophane tape was applied over the cuts, and the tape was quickly peeled off, and the appearance of the printed coating was evaluated on the following 5-point scale. The test was performed at least one day after curing. (Evaluation Criteria) ◯: No peeling of the printed coating was observed. ◯△: 70% or more of the printed coating remained on the decorative sheet substrate in terms of area ratio. △: 50% or more and less than 70% of the printed coating remained on the decorative sheet substrate in terms of area ratio. Δ×: 10% or more and less than 50% of the printed coating remained on the decorative sheet substrate in terms of area ratio. ×: Less than 10% of the printed coating remained on the decorative sheet substrate in terms of area ratio.

[0070] The evaluation results for the cases where each primer composition satisfying the (meth)acryloyl group equivalent of 80 to 750 g / eq. was used (Examples 1 to 7) are shown in Table 1. The evaluation results for the case where no coating layer (A) was provided (Comparative Example 1) and the case where each primer composition not satisfying the (meth)acryloyl group equivalent of 80 to 750 g / eq. was used (Comparative Examples 2 to 3) are shown in Table 2. Note that blank spaces indicate that no composition was used.

[0071] [Table 1]

[0072] [Table 2]

[0073] In Tables 1 and 2, *1 indicates the following. (Absolute value of (meth)acryloyl group equivalent of primer composition / Absolute value of (Y)kGy) In Tables 1 and 2, the abbreviations stand for the following: DPA-600T: Hexafunctional acrylate monomer manufactured by Zhangjiagang Dongya Diac Biochemical Co., Ltd. Miramer M3130: Trifunctional acrylate monomer manufactured by MIWON Luxidia RS28-360: Acrylic acrylate manufactured by DIC Miramer M2100: Bifunctional acrylate monomer manufactured by MIWON Miramer M2200: Bifunctional acrylate monomer manufactured by MIWON Luxidia CH-S-1371: Acrylic acrylate manufactured by DIC Omnirad184: Photoinitiator manufactured by BASF Viscoat 190D: Acrylate monomer manufactured by Osaka Organic Chemical Industry Ltd. Miramer M202: Bifunctional acrylate monomer manufactured by MIWON Miramer M220: Bifunctional acrylate monomer manufactured by MIWON Photomer 6184: Urethane acrylate oligomer from IGM Resins BV Nipsil E170: Silica manufactured by Tosoh Silica Corporation Minex 8F: Sodium potassium aluminum silicate manufactured by Shiraishi Kogyo Co., Ltd. · Rancowax PP1362D: Polypropylene wax manufactured by Lubrizol Japan Co., Ltd. BYK A501: Defoamer manufactured by BYK Japan Luxidia CH-S-1372: Acrylic acrylate manufactured by DIC Acrylic resin manufactured by Taisei Fine Chemical Co., Ltd. Untreated PP: A sample in which coating layer (A) is applied to the untreated surface of a polypropylene film (Okamoto's "Basic Color PP Sheet White", 0.4 mm thick). Corona-treated PP: A sample in which the coating layer (A) is applied to the surface-treated surface of a polypropylene film (Okamoto's "Basic Color PP Sheet White", 0.4 mm thick).

[0074] [Examples 1, 8 to 10, and Comparative Example 4 (Table 3)] The primer composition prepared by mixing the components shown in Table 3 (composition of coating layer (A)) was applied to the surface-treated or untreated surface of a polypropylene film (Okamoto's "Basic Color PP Sheet White", 0.4 mm thick) using a bar coater #6 to form a coating layer (A). Next, a UV irradiation device (GS Yuasa Corporation) equipped with an air-cooled high-pressure mercury lamp (output 120 W / cm1 lamp) and a belt conveyor was used, and the coated material was placed on the conveyor and passed directly under the lamp (irradiation distance 15 cm) at a speed of 25 m / min for an arbitrary number of times to make the coating layer (A) tack-free. The accumulated light amount at which the coating layer became tack-free is shown in Table 3. Next, the electron beam-curable coating composition prepared by mixing the components shown in Table 3 (composition of coating layer (B)) was applied to the coating layer (A) using a bar coater #6 to form a coating layer (B). Next, the coating layer (B) and the coating layer (A) were cured by irradiating them with electron beams under the conditions shown in Table 3 using a curtain-type electron beam irradiation device ("Electrocurtain EC250 / 15 / 180L" manufactured by Iwasaki Electric Co., Ltd.) The initial adhesion and cross-cut adhesion were evaluated in the same manner as in Examples 1 to 7 and Comparative Examples 1 to 3.

[0075] The evaluation results for the cases where a primer composition satisfying (absolute value of (meth)acryloyl group equivalent of primer composition / absolute value of (Y)kGy)<10 was used (Examples 1, 8 to 10), and for the case where a primer composition not satisfying (absolute value of (meth)acryloyl group equivalent of primer composition / absolute value of (Y)kGy)<10 was used (Comparative Example 4) are shown in Table 3. Note that blanks indicate that no compound was used.

[0076] [Table 3]

[0077] In Table 3, *1 indicates the following. (Absolute value of (meth)acryloyl group equivalent of primer composition / Absolute value of (Y)kGy) In the three tables, the abbreviations stand for the following: DPA-600T: Hexafunctional acrylate monomer manufactured by Zhangjiagang Dongya Diac Biochemical Co., Ltd. Miramer M2200: Bifunctional acrylate monomer manufactured by MIWON Omnirad184: Photoinitiator manufactured by BASF Viscoat 190D: Acrylate monomer manufactured by Osaka Organic Chemical Industry Ltd. Miramer M202: Bifunctional acrylate monomer manufactured by MIWON Miramer M220: Bifunctional acrylate monomer manufactured by MIWON Miramer M3130: Trifunctional acrylate monomer manufactured by MIWON Photomer 6184: Urethane acrylate oligomer from IGM Resins BV Nipsil E170: Silica manufactured by Tosoh Silica Corporation Minex 8F: Sodium potassium aluminum silicate manufactured by Shiraishi Kogyo Co., Ltd. · Rancowax PP1362D: Polypropylene wax manufactured by Lubrizol Japan Co., Ltd. BYK A501: Defoamer manufactured by BYK Japan Untreated PP: A sample in which coating layer (A) is applied to the untreated surface of a polypropylene film (Okamoto's "Basic Color PP Sheet White", 0.4 mm thick). Corona-treated PP: A sample in which the coating layer (A) is applied to the surface-treated surface of a polypropylene film (Okamoto's "Basic Color PP Sheet White", 0.4 mm thick).

Claims

1. A decorative sheet for building materials, comprising at least a primer layer and a coating layer formed in this order on a substrate sheet made of a polyolefin resin, The decorative sheet for building materials, characterized in that the primer layer is a cured product of an active energy ray-curable primer composition that contains a compound having a (meth)acryloyl group, has a (meth)acryloyl group equivalent in the range of 80 to 750 g / eq., and does not contain solid fine particles, and the coating layer is a cured product of an electron beam-curable coating composition that contains a matting agent.

2. The decorative sheet for building materials according to claim 1, containing the compound having a (meth)acryloyl group in an amount of 50 to 100 mass % relative to the solid content of the active energy ray-curable primer composition.

3. A decorative sheet for building materials as described in claim 1, wherein the compound having a (meth)acryloyl group is a monofunctional (meth)acrylate, a di- or higher functional (meth)methacrylate, or a polymerizable oligomer.

4. A decorative sheet for building materials as described in claim 1, wherein the matting agent contained in the electron beam curable coating composition has a volume average particle size of 0.5 to 25 μm and is contained in an amount of 0.5 to 50 mass% relative to the electron beam curable coating composition.

5. A step 1 of forming a coating layer (A) of an active energy ray-curable primer composition containing a compound having a (meth)acryloyl group and having a (meth)acryloyl group equivalent in the range of 80 to 750 g / eq. on a substrate sheet made of a polyolefin resin; Step 2 of forming a coating layer (B) of an electron beam curable coating composition containing a matting agent on the coating layer (A); A step 3 of irradiating the surface layer side of the coating layer (B) with an electron beam; A method for producing a decorative sheet for building materials having the following in this order: The (meth)acryloyl group equivalent of the primer composition in the step 1 and the electron beam irradiation dose (Y) kGy in the step 3 are [0010] A method for producing a decorative sheet for building materials, comprising the steps of:

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