JP2023166728A - Electron beam-curable matte coating agent, and method for producing electron beam-curable matte coating film - Google Patents

Abstract

To provide an electron beam-curable matte coating agent that has a desired matte effect by electron beam irradiation without using excimer UV, and concurrently has physical attributes unique to a decorative sheet, such as scratch and stain resistance, and a method for producing an electron beam-curable matte coating film.SOLUTION: An electron beam-curable matte coating agent contains a compound (A) with a weight average molecular weight of 2000 or more and a bifunctional methacryl monomer (B), and satisfies (1) and (2). (1) The bifunctional methacryl monomer (B) has a number average molecular weight of 150-400. (2) The mass ratio between the compound (A) and the bifunctional methacryl monomer (B) is in the range of (A):(B)=1:9-9:1.SELECTED DRAWING: None

Description

The present invention relates to a matte coating agent using an electron energy beam curable composition and a method for producing an electron beam curable matte coating film.

Decorative sheets are often used for the surface decoration of building interiors and fittings, vehicle interiors, etc., and various coatings are applied to the surface layer of the decorative sheet for the purpose of protection and beauty. While it is common for coating agents for painting to contain matting agents such as silica, mainly for the purpose of reducing gloss and improving design, the use of matting agents may affect the suitability of the coating. In recent years, excimer UV has attracted attention as a method for reducing gloss without using a matting agent because it may affect the color of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the surface of the image.
For example, a decorative sheet is known that has low gloss due to a matting effect without adding particles using excimer UV, which irradiates excimer light with a short wavelength (172 nm) (see, for example, Patent Document 1).
However, for decorative sheets, it is not only the appearance such as low gloss, but also the physical properties such as scratch resistance and stain resistance that are extremely important. The current situation is that it is still not sufficient to have both.

JP 2021-24102 Publication

The problem to be solved by the present invention is to provide an electron beam-curable matte coating that has the desired matte effect by electron beam irradiation without using excimer UV, and physical properties unique to decorative sheets such as scratch resistance and stain resistance. An object of the present invention is to provide a method for producing an electron beam-curable matte coating film.

An object of the present invention is to provide an electron beam curable matte coating agent and a method for producing an electron beam curable matte coating film according to a specific formulation.

The present inventors have developed an electron beam-curable matte coating that uses a compound (A) having a weight average molecular weight of 2,000 or more and a bifunctional (meth)acrylic monomer (B) having a number average molecular weight of 150 to 400 in a specific ratio. It has been found that the above-mentioned problem can be solved.

That is, the present invention is characterized in that it contains a compound (A) having a weight average molecular weight of 2000 or more and a bifunctional (meth)acrylic monomer (B), and satisfies (1) and (2). Provides a line-curable matte coating agent.
(1) The number average molecular weight of the difunctional (meth)acrylic monomer (B) is 150 to 400.
(2) The mass ratio of the compound (A) and the bifunctional (meth)acrylic monomer (B) is in the range of (A):(B)=1:9 to 9:1.

Further, the present invention provides that the bifunctional (meth)acrylic monomer (B) is ethylene oxide-modified 1,6-hexanediol diacrylate, 1,6-hexanediol diacrylate, 1,9 nonanediol diacrylate, hydroxybivalent Provided is an electron beam-curable matte coating agent that is at least one bifunctional (meth)acrylic monomer selected from the group consisting of neopentyl glycol diacrylate phosphate and tripropylene glycol diacrylate.

The present invention also provides the electron beam curable matte coating agent according to claim 1, which further contains a trifunctional or higher functional (meth)acrylic monomer.

Further, the present invention comprises, in this order, a step (I) of forming a coating film of an electron beam curable matte coating agent on a substrate, and a step (II) of irradiating the coating film with an electron beam. A method for producing a matte coating film, wherein the electron beam curable matte coating agent is the electron beam curable matte coating agent, and the electron beam irradiation dose in the electron beam irradiation step (II) is Provided is a method for producing an electron beam-curable matte coating film, characterized in that the energy consumption is 100 kGy or less.

With the electron beam curable matte coating agent of the present invention, it is possible to have a sufficient matting effect by electron beam irradiation without using excimer UV, and physical properties unique to decorative sheets such as scratch resistance and stain resistance.

The electron beam curable matte coating agent of the present invention contains a compound (A) having a weight average molecular weight of 2000 or more and a bifunctional (meth)acrylic monomer (B), and satisfies (1) and (2). It is characterized by
(1) The number average molecular weight of the difunctional (meth)acrylic monomer (B) is 150 to 400.
(2) The mass ratio of the compound (A) and the bifunctional (meth)acrylic monomer (B) is in the range of (A):(B)=1:9 to 9:1.

In the present invention, "(meth)acrylic monomer" refers to one or both of an acrylic monomer and a methacrylic monomer.

The compound (A) used in the electron beam curable matte coating agent of the present invention is not particularly limited as long as it has a weight average molecular weight of 2000 or more, and known compounds can be used. Among these, compounds such as (meth)acrylic polymers and (meth)acrylic oligomers made from acrylic monomers are considered from the viewpoint of compatibility and blending stability with the essential component bifunctional (meth)acrylic monomer (B). It is preferable.
By having a weight average molecular weight of 2000 or more, it is possible to have sufficient matting effect upon electron beam irradiation and physical properties unique to decorative sheets such as scratch resistance and stain resistance.

In the present invention, the weight average molecular weight and number average molecular weight are values measured by the following method.
Measuring device: HLC-8220 manufactured by Tosoh Corporation
Column: Guard column H _XL -H manufactured by Tosoh Corporation
+TSKgel G5000HXL manufactured by Tosoh Corporation
+TSKgel G4000HXL manufactured by Tosoh Corporation
+TSKgel G3000HXL manufactured by Tosoh Corporation
+TSKgel G2000HXL manufactured by Tosoh Corporation
Detector; RI (differential refractometer)
Data processing: Tosoh Corporation SC-8010
Measurement conditions: Column temperature 40℃
Solvent Tetrahydrofuran
Flow rate 1.0ml/min Standard: Polystyrene Sample: 0.4% by mass of tetrahydrofuran solution in terms of resin solid content filtered through a microfilter (100μl)

Examples of the compound (A) include (meth)acrylic polymers. The (meth)acrylic monomer constituting the (meth)acrylic polymer is not particularly limited, and includes methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and isopropyl (meth)acrylate. , n-butyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, n-octyl (meth)acrylate ) acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate ) acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, isodecyl (meth)acrylate, isomystyryl (meth)acrylate, isostearyl (meth)acrylate acrylate, propylheptyl (meth)acrylate, isoundecyl (meth)acrylate, isododecyl (meth)acrylate, isotridecyl (meth)acrylate, isopentadecyl (meth)acrylate, isohexadecyl (meth)acrylate, isoheptadecyl (meth)acrylate, etc. Examples include alkyl group-containing acrylic monomers, which may be used alone or in combination.
The (meth)acrylic polymer can be obtained by polymerizing or copolymerizing the (meth)acrylic monomers alone or in combination by a known method.

Further, the (meth)acrylic polymer may have a functional group within a range that does not impair the effects of the present invention. Examples of the functional group include a hydroxyl group, an acidic group, and a (meth)acryloyl group.
The (meth)acrylic polymer containing a hydroxyl group includes the above (meth)acrylic monomer, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl Hydroxyl group-containing (meth)acrylic monomers such as (meth)acrylate, 2-hydroxy-3-chloropropyl (meth)acrylate, and 2-hydroxy-3-phenoxypropyl (meth)acrylate are copolymerized by a known method. can get.
In addition, the (meth)acrylic polymer containing an acidic group is composed of the (meth)acrylic monomer and (meth)acrylic acid, 2-acryloyloxyethylsuccinic acid, 2-acryloyloxyethyl phthalic acid, 2-methacryloyloxyethylhexyl Obtained by copolymerizing acidic group-containing monomers such as hydrophthalic acid, (meth)acrylic acid dimer, maleic anhydride, maleic acid, crotonic acid, itaconic acid, fumaric acid, muconic acid, citraconic acid, etc. by a known method. .

Furthermore, a (meth)acrylic polymer having a functional group such as a (meth)acryloyl group can also be used. For example, (poly)urethane (meth)acrylate, (poly)acrylic (meth)acrylate, (poly)epoxy (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, having a weight average molecular weight of 2000 or more, Polyolefin (meth)acrylate, polystyrene (meth)acrylate, macromonomer, etc. can be used.

The bifunctional (meth)acrylic monomer (B) used in the electron beam curable matte coating agent of the present invention preferably has a number average molecular weight of 150 to 400. In addition, "bifunctional" of the bifunctional (meth)acrylic monomer (B) in this invention represents having two (meth)acryloyl groups.
Examples of difunctional (meth)acrylic monomers include 1,4-butanediol di(meth)acrylate (molecular weight 198.2) and 3-methyl-1,5-pentanediol di(meth)acrylate (molecular weight 226.27). ), 1,6-hexanediol di(meth)acrylate (molecular weight 314), 1,9 nonanediol diacrylate (molecular weight 268), neopentyl glycol di(meth)acrylate (molecular weight 240.3), 2-methyl- 1,8-octanediol di(meth)acrylate (molecular weight 268.3), 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate (molecular weight 160.2), tricyclodecane dimethanol di (meth)acrylate (molecular weight 304.3), ethylene glycol di(meth)acrylate (molecular weight 198.2), diethylene glycol di(meth)acrylate (molecular weight 242.2), triethylene glycol di(meth)acrylate (molecular weight 286. 3) Di(meth)acrylate of dihydric alcohol such as dipropylene glycol di(meth)acrylate (molecular weight 242.2), hydroxybivalic acid neopentyl glycol diacrylate (molecular weight 312), tripropylene glycol di(meth)acrylate, etc. Acrylate, di(meth)acrylate of tris(2-hydroxyethyl)isocyanurate (molecular weight 261.2), di(meth)acrylate of diol obtained by adding 4 moles or more of ethylene oxide or propylene oxide to 1 mole of neopentyl glycol. ) acrylate, di(meth)acrylate of diol obtained by adding 2 moles of ethylene oxide or propylene oxide to 1 mole of bisphenol A, and the like.
Among them, 1,6-hexanediol di(meth)acrylate, ethylene oxide-modified 1,6-hexanediol di(meth)acrylate, 1,9 nonanediol diacrylate, hydroxybivalic acid neopentyl glycol diacrylate, Propylene glycol diacrylate is more preferred.

In the electron beam curable matte coating agent of the present invention, a trifunctional or higher functional (meth)acrylic monomer may also be used. Note that "trifunctional or more" herein refers to having three or more (meth)acryloyl groups.

Trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol poly(meth)acrylate, etc. Poly(meth)acrylate of trihydric or higher polyhydric alcohol such as (meth)acrylate, tri(meth)acrylate of triol obtained by adding 3 or more moles of ethylene oxide or propylene oxide to 1 mole of glycerin, trimethylolpropane Triol di- or tri(meth)acrylate obtained by adding 3 moles or more of ethylene oxide or propylene oxide to 1 mole, and diol di- or tri(meth)acrylate obtained by adding 4 mole or more of ethylene oxide or propylene oxide to 1 mole of bisphenol A. Examples include poly(meth)acrylates of polyoxyalkylene polyols such as (meth)acrylates.
Among these, ethylene oxide-modified trimethylolpropane triacrylate is more preferred.
The amount of trifunctional or more functional (meth)acrylate added is preferably 30% by mass or less based on the total amount of the coating agent.

Furthermore, a mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate (sometimes abbreviated as DPHA), ditrimethylolpropane tetraacrylate (sometimes abbreviated as DTMPTA), 3 mol or more per 1 mol of trimethylolpropane Trimethylolpropane ethylene oxide adduct tri(meth)acrylate, which is a tri(meth)acrylate of a triol obtained by adding ethylene oxide, may also be used. Typical examples of the trimethylolpropane ethylene oxide adduct tri(meth)acrylate include trimethylolpropane ethylene oxide (hereinafter ethylene oxide may be referred to as "EO") modified (n≒3) triacrylate. It will be done.

The mass ratio of the compound (A) and the bifunctional (meth)acrylic monomer (B) must be in the range of (A):(B)=1:9 to 9:1.
Within this range, it is possible to have both a sufficient matte effect upon electron beam irradiation and physical properties unique to decorative sheets such as scratch resistance and stain resistance.

(Photopolymerization initiator)
The electron beam curable matte coating agent of the present invention may contain a photopolymerization initiator, if necessary. As the photopolymerization initiator used in this case, any known one may be used.

Among these, radical polymerization type photopolymerization initiators are preferable, and examples thereof include α-hydroxyalkyl ketone photopolymerization initiators that do not cause coloring of the solution when the active energy ray-curable compound is dissolved and cause less yellowing over time. Examples of the α-hydroxyalkyl ketone photopolymerization initiator include 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1-(4-i-propylphenyl)-2-hydroxy-2-methylpropane -1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexylphenylketone and the like. Furthermore, phenylglyoxolate-based photopolymerization initiators are also preferred. Examples of the phenylglyoxolate photopolymerization initiator include methylbenzoylformate. Among them, 1-hydroxycyclohexyl phenyl ketone is preferred.

Further, as other radical polymerization type photopolymerization initiators, monoacylphosphine oxide photopolymerization initiators having absorption wavelengths in the long wavelength region of ultraviolet rays may be used in combination as appropriate. Monoacylphosphine oxide photopolymerization initiators include 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, excluding bisacylphosphine oxides that color when dissolved in active energy ray-curable compounds. -dimethoxybenzoyl-diphenylphosphine oxide, 2,6-dichlorobenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-phenylphosphine acid methyl ester, 2-methylbenzoyl-diphenylphosphine oxide, pivaloyl Examples include monoacylphosphine oxides such as phenylphosphinate isopropyl ester, and among these, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide is a UV-based compound with an emission wavelength of 385 nm or 395 nm. It is more preferable to have a UV absorption wavelength that matches the emission wavelength range of the LED, since suitable curability can be obtained and yellowing of the cured film is less.

The photopolymerization initiators described above may be used alone or in combination of two or more. The total amount of the photopolymerization initiator added is preferably in the range of 0% by mass to 30% by mass based on the total amount of the coating agent. More preferably, the amount is in the range of 1% by mass to 25% by mass based on the total amount of the coating agent.

(Organic solvent)
Moreover, an organic solvent can be added as a diluent to the electron beam curable matte coating agent of the present invention, if necessary.
As the organic solvent, any solvent can be used as long as it dissolves the compound having a (meth)acryloyl group to be used. For example, 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, methanol, Alcohols such as ethanol, isopropyl alcohol, n-butanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, alkylene glycol monoalkyl ethers such as ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether Examples include ether esters such as acetate, and a mixture of these may be used.
However, when the purpose of environmental protection is to thoroughly reduce the amount of organic solvents evaporated into the atmosphere, that is, to reduce volatile organic compounds (VOC), it is more preferable not to include the above-mentioned organic solvents.

From the viewpoint of coatability, the electron beam curable matte coating agent of the present invention is preferably adjusted to a viscosity that can be coated in the method for producing an electron beam curable matte coating film of the present invention described below. . The viscosity is preferably adjusted to 30 to 3000 mPa·s. In particular, when a polymer having a high molecular weight and high viscosity is used in combination, the viscosity can be adjusted to the desired level by diluting with an organic solvent or heating as necessary.

(Additive)
Other electron beam-curable matte coating agents of the present invention include matting agents, polymerization inhibitors, leveling agents, thixotropic agents, waxes, desiccants, thickeners, anti-sagging agents, plasticizers, dispersants, and sedimentation agents. It is possible to contain inhibitors, antifoaming agents, ultraviolet absorbers, light stabilizers, and the like.

(Base material)
The base material used in the present invention can be used without particular limitation as long as it is a base material for which a matte design is desired. For example, in the case of a decorative sheet for building materials, a general-purpose base material sheet used for decorative sheets can be used as the base material.
The base sheet is not particularly limited, and a sheet (film) or paper made of a general-purpose thermoplastic resin is used for general decorative sheets.
Examples of sheets (films) made of thermoplastic resins include polyethylene, ethylene-α olefin copolymer, polypropylene, polymethylpentene, polybutene, ethylene-propylene copolymer, propylene-butene copolymer, ethylene- Polyolefin resins such as vinyl acetate copolymer, saponified ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester copolymer, polyvinyl chloride, polyethylene terephthalate (PET), polybutylene terephthalate, polyamide, polycarbonate, polyethylene naphthalate, ionomer, acrylic ester polymer, methacrylic ester polymer, and the like. The base sheet may be formed by using these resins alone or in combination of two or more.

The base sheet may be colored, and if necessary, it may contain fillers, matting agents, foaming agents, flame retardants, lubricants, antistatic agents, antioxidants, ultraviolet absorbers, light stabilizers, etc. Various additives may be included. The thickness of the base sheet can be appropriately set depending on the purpose of the final product, how it is used, etc., but is generally preferably 20 to 300 μm.

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

Examples of the paper base material for the decorative sheet include paper sheets such as thin paper, plain paper, reinforced paper, resin-impregnated paper, titanium paper, and the like.

Alternatively, a wood decorative board or the like which is commonly used as a decorative board may be used as the base material. Examples of the wood base material for the wood decorative board include known materials such as plywood, particle board, hardboard, and MDF, which have been conventionally used as wood base materials for decorative boards, furniture, building materials, and the like. Moreover, it does not matter what manufacturing method these known base materials are obtained from.
In addition, noncombustible materials that can be used as base materials include gypsum board, gypsum board, perforated board construction materials made of calcium silicate boards, ceramic boards such as ceramics, porcelain, stoneware, earthenware, glass, and enamel, and iron plates. Examples include metal plates such as galvanized steel plates, polyvinyl chloride sol coated steel plates, aluminum plates, and copper plates.

(Manufacture of electron beam curable matte coating agent)
The electron beam curable matte coating agent used in the present invention is produced by mixing and dispersing a compound with a weight average molecular weight of 2000 or more, a polyfunctional (meth)acrylic monomer, a photopolymerization initiator, and various other additives. can be manufactured.
Using a commonly used dispersing machine such as a roller mill, ball mill, pebble mill, attritor, or sand mill, the size of the grinding media, the filling rate of the grinding media, the dispersion treatment time, etc. can be adjusted as appropriate.
If bubbles or unexpected coarse particles are contained in the coating agent, it is preferable to remove them by filtration or the like, since this will reduce the quality of the coated product. A conventionally known filter can be used.

(Method for forming coating film)
The electron beam curable matte coating agent used in the present invention can be formed into a coating film by a known coating/printing method. Specific examples of coating methods include roll coaters, gravure coaters, gravure offset coaters, flexo coaters, air doctor coaters, blade coaters, air knife coaters, squeeze coaters, impregnation coaters, transfer roll coaters, kiss coaters, and curtain coaters. , a cast coater, a spray coater, a die coater, an offset printer, a screen printer, etc. can be appropriately employed.

(Step (I) of forming a coating film)
When the coating agent used contains an organic solvent, the coating film formed by the above-mentioned method is dried in a drying oven or the like, and then cured with an electron beam to obtain a cured coating film.

(Electron beam irradiation step (II))
After the step (I), an electron beam irradiation device is used for the step (II) of electron beam irradiation. The accelerating voltage is preferably 200 kV or less. The irradiation amount is preferably 100 kGy or less, more preferably in the range of 5 to 50 kGy.
A desired matte effect can be obtained by lowering the irradiation.

The thickness of the coating film thus obtained is preferably in the range of 0.5 to 100 μm, and most preferably in the range of 10 to 50 μm. By having a film thickness within this range, the effects of the present invention can be maximized.

Furthermore, the manufacturing method of the present invention can be widely applied not only to the above-mentioned construction material applications such as decorative sheets, but also to surface coating applications such as furniture, musical instruments, office supplies, sporting goods, toys, and the like.

Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that parts and parts by mass in the following examples represent % by mass.

In this example, the weight average molecular weight (Mw) and number average molecular weight (Mn) are values measured using gel permeation chromatography (GPC) under the following conditions.

Measuring device: HLC-8220 manufactured by Tosoh Corporation
Column: Guard column H _XL -H manufactured by Tosoh Corporation
+TSKgel G5000HXL manufactured by Tosoh Corporation
+TSKgel G4000HXL manufactured by Tosoh Corporation
+TSKgel G3000HXL manufactured by Tosoh Corporation
+TSKgel G2000HXL manufactured by Tosoh Corporation
Detector; RI (differential refractometer)
Data processing: Tosoh Corporation SC-8010
Measurement conditions: Column temperature 40℃
Solvent Tetrahydrofuran
Flow rate 1.0ml/min Standard: Polystyrene Sample: 0.4% by mass of tetrahydrofuran solution in terms of resin solid content filtered through a microfilter (100μl)

(Example 1 Electron beam curable matte coating agent)
As the compound (A), 20 parts by mass of a compound (A-1) having a weight average molecular weight of 55,000 and a hydroxyl group, as the bifunctional (meth)acrylic monomer (B), ethylene oxide modified 1,6-hexanediol diacrylate (M202 Miwon) ), 10 parts by mass of 1-hydroxy-cyclohexyl-phenyl-ketone "Omnirad 184" manufactured by BASF, and 34.8 parts by mass of ethyl acetate were mixed and thoroughly stirred with a stirrer to make a total of 144.8 parts by mass. An electron beam curable matte coating agent (1) was prepared.

(Examples 2 to 13 and Comparative Examples 1 to 5)
According to the formulations shown in Tables 1 to 3, the electron beam curable matte coating agents of Examples 2 to 13 and Comparative Examples 1 to 5 were thoroughly mixed and dispersed to obtain electron beam curable matte coating agents.

(Process of forming a coating film of electron beam curable matte coating agent)
The electron beam curable matte coating agent obtained in the above Examples and Comparative Examples was applied to a polyester film (A4100, thickness 50 μm, manufactured by Toyobo Co., Ltd.) using a bar coater (#10). formed a layer.

(Process of electron beam irradiation (II)
In step (II) of irradiating the coating layer with an electron beam after step (I), an accelerating voltage is Electron beam irradiation was performed at 80 kV and irradiation dose of 15 kGy to obtain a matte coating film.

The produced electron beam curable matte coating agents were each evaluated for gloss, scratch resistance, and stain resistance.

(Evaluation item 1: Gloss value)
In order to measure the specular gloss value of the obtained coating film according to JIS Z8741, the gloss value was measured using a gloss meter ("MULTI GLOSS 268A" manufactured by Konica Minolta), and the gloss value was 40. It was judged pass/fail. The measurement conditions for the gloss value were an incident angle of 60° and a reflection angle of 60°.
(Evaluation criteria)
○: Less than 40 ×: 40 or more

(Evaluation item 2: low gloss area)
Regarding the obtained coating film, the area where the gloss was reduced to a gloss value of less than 40 was visually confirmed, and pass/fail was determined based on the area of 80%. The measurement conditions for the gloss value are in accordance with evaluation item 1.
(Evaluation criteria)
〇: 80% or more ×: less than 80%

(Evaluation item 3: Scratch resistance)
Steel wool (BON STAR No. 0000, manufactured by Nippon Steel Wool Co., Ltd.) was applied to the surface of the obtained coating film and moved back and forth 10 times under a load of 250 g/cm ² to determine the number of scratches on the coating film. Evaluations were made by setting criteria for each stage. The evaluation criteria for scratch resistance are as follows.
(Evaluation criteria)
○: No scratches are seen.
△: Slight change in gloss and scratches are observed, but there is no problem in practical use.
×: Change in gloss and noticeable scratches are observed.

[Evaluation item 4: Stain resistance]
In accordance with the JAS Special Plywood Contamination A Test, contaminants were applied to the surface of the decorative board, and after 4 hours, the surface was wiped off with an alcohol-containing rag, and the extent to which the contaminants remained was visually observed. A commercially available office black marker was used as the contaminant.
(Evaluation criteria)
○: There is no residual contaminant at all.
△: Although some contaminants remain, it is slight and poses no practical problem.
×: Significant contaminants remain.

The evaluation results of each electron beam curable matte coating agent and the produced matte coating film are shown in Tables 1 to 3.
Note that all numerical values in the table are parts by mass or % by mass, and those other than ethyl acetate indicate solid content. In addition, a blank column indicates that it is not blended.

Abbreviations in the table indicate that the following raw materials were used.
- Compound (A)-1 The functional group is a hydroxyl group.
-Compound (A)-2 The functional group is an acryloyl group.
-Compound (A)-3 The functional group is an acryloyl group.
-Compound (A)-4 The functional group is an acryloyl group.
・EOHDDA: Ethylene oxide modified 1,6-hexanediol diacrylate, Miramer M202 (manufactured by Miwon)
・HDDA: 1,6-hexanediol diacrylate, Miramer M200 (manufactured by Miwon)
・1,9-ND-A: Light acrylate 1,9-ND-A, 1,9 nonanediol diacrylate, (manufactured by Kyoeisha Chemical Co., Ltd.)
・HPN: Hydroxybivalic acid neopentyl glycol diacrylate, Miramer M210 (manufactured by Miwon)
・TPGDA: tripropylene glycol diacrylate, Miramer220 (manufactured by Miwon)
・EOTMPTA: Ethylene oxide modified trimethylolpropane triacrylate, Miramer M3130 (manufactured by Miwon)
・DPHA: Dipentaerythritol hexaacrylate, Miramer M600 (manufactured by Miwon)
・Other acrylate compounds (Y): trifunctional weight average molecular weight 600
・Omnirad 184: 1-hydroxycyclohexylphenyl ketone (manufactured by IGM Resins B.V.)

As a result, it is clear that the electron beam-curable matte coating agent of the present invention has both a sufficient matte effect, scratch resistance, and stain resistance.

Claims (4)

An electron beam curable matte coating characterized by containing a compound (A) having a weight average molecular weight of 2000 or more and a bifunctional (meth)acrylic monomer (B) and satisfying (1) and (2). agent.
(1) The number average molecular weight of the difunctional (meth)acrylic monomer (B) is 150 to 400.
(2) The mass ratio of the compound (A) and the bifunctional (meth)acrylic monomer (B) is in the range of (A):(B)=1:9 to 9:1. The bifunctional (meth)acrylic monomer (B) is ethylene oxide-modified 1,6-hexanediol diacrylate, 1,6-hexanediol diacrylate, 1,9 nonanediol diacrylate, neopentyl glycol hydroxybivalate. The electron beam curable matte coating agent according to claim 1, which is at least one bifunctional (meth)acrylic monomer selected from the group consisting of diacrylate and tripropylene glycol diacrylate. The electron beam curable matte coating agent according to claim 1, further comprising a trifunctional or more functional (meth)acrylic monomer. Step (I) of forming a coating film of an electron beam curable matte coating agent on the substrate;
Step (II) of irradiating the coating film with an electron beam,
A method for producing a matte coating film having the following steps,
The electron beam curable matte coating agent is the electron beam curable matte coating agent according to any one of claims 1 to 3,
A method for producing a matte coating film, characterized in that the dose of electron beam irradiation in the electron beam irradiation step (II) is 100 kGy or less.