JP2022020989A - Active energy ray-curable coating agent and coated building material using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an active energy ray curable property having matte low gloss, excellent printability without uneven coating, and cellophane tape (registered trademark) property without using an organic solvent. It is to provide a coating agent.
SOLUTION:
Monofunctional (meth) acrylate monomers, urethane (meth) acrylates, which are reaction products of dicyclohexylmethane 4,4'-diisocyanate and hydroxyl group-containing (meth) acrylates as compounds having multiple (meth) acryloyl groups, and / Or an active energy ray-curable coating agent containing an acrylic resin containing a (meth) acryloyl group having a double bond equivalent of 100 to 1000 / mol. However, (1) monofunctional (meth) acrylate monomer is 10 to 60% by mass of the total amount of the cured component.
(2) The urethane (meth) acrylate is 4 to 30% by mass of the total amount of the cured component.
(3) The acrylic resin is 0.1 to 20% by mass of the total amount of the cured component.
[Selection diagram] None

Description

The present invention provides an active energy ray-curable coating agent for forming a surface protective layer of a decorative sheet for furniture, flooring, etc. inside a building such as a house, and a film formed from the active energy ray-curable coating agent. Regarding the painted building materials that we have.

Conventionally, decorative sheets have been widely used for furniture, flooring, etc. inside buildings such as houses, and the surface layer thereof is coated with various coatings for the purpose of protection and beautification. Decorative sheet is a general term for printed matter for decorating the surface by laminating it with a member such as wood.
In the field of interior materials for building materials, from the viewpoint of furniture, walls, ceilings, floors, high designability of decorative sheets, good workability, low cost, and economic efficiency due to the ability to handle small lots, so-called painting has been replaced with sheets. It's progressing.
On the other hand, at present, most of the coating agents for forming the surface protective layer of domestic decorative sheets use polymers and organic solvents, and about 30 to 70% of the total amount of the coating agent is organic in terms of solid content mass ratio. Since it is a solvent, it is inevitable that a large amount of organic solvent evaporates into the atmosphere during painting (for example, Cited Document 1).
As one of the methods for reducing the amount of transpiration of organic solvents into the atmosphere, that is, reducing VOCs, a monomer-based solvent-free coating agent can be mentioned, but when the base material is paper, the paper base material suddenly becomes Since a sufficiently uniform coating film is not formed due to permeation, uneven coating is likely to occur, and it tends to be difficult to obtain good printing suitability.
In addition, in order to give a more luxurious feeling to the surface of painted building materials such as decorative sheets these days, there is a tendency to prefer matte ones with reduced gloss, but if an organic solvent is used, it is used together due to solvent volatilization. There is an advantage that silica etc. can be cueed from the film surface of the surface protective layer to obtain a low gloss effect, but since this mechanism cannot be adopted when no solvent is used, it is difficult to obtain a low gloss coating film. Is likely to occur. The active energy ray-curable coating agent of the present invention overcomes these disadvantages without using an organic solvent.
Further, the active energy ray-curable coating agent of the present invention uses adhesive tapes when actually processing a decorative sheet or the like at a construction site, and temporarily fixes a notice such as memos on the decorative sheet or for alignment. It also has cellophane tape (registered trademark) properties that indicate the resistance of the surface of the decorative sheet when the temporary fixing tapes are peeled off.

Japanese Unexamined Patent Publication No. 2018-184583

An object of the present invention is to provide an active energy ray-curable coating agent having matte-like low gloss, excellent printability without uneven coating, and cellophane tape (registered trademark) resistance without using an organic solvent. To provide.

The present invention is characterized by containing a specific amount of a monofunctional (meth) acrylate monomer and an acrylic resin containing a specific urethane (meth) acrylate and / or a (meth) acryloyl group in the total amount of the curing component. Regarding linear curable coating agents.

That is, the present invention is a monofunctional (meth) acrylate monomer, a reaction product of dicyclohexylmethane 4,4'-diisocyanate as a compound having a plurality of (meth) acryloyl groups, and a hydroxyl group-containing (meth) acrylate. An active energy ray-curable coating agent containing an acrylic resin containing a (meth) acryloyl group having a meta) acrylate and / or a double bond equivalent of 100 to 1000 / mol.
(1) Monofunctional (meth) acrylate monomer is 10 to 60% by mass of the total amount of the cured component.
(2) Urethane (meth) acrylate, which is a reaction product of dicyclohexylmethane 4,4'-diisocyanate and hydroxyl group-containing (meth) acrylate, is 4 to 30% by mass of the total amount of the cured component.
(3) Acrylic resin containing a (meth) acryloyl group having a double bond equivalent of 100 to 1000 / mol is 0.1 to 20% by mass of the total amount of the cured component.
The present invention relates to an active energy ray-curable coating agent characterized by being.

The present invention also relates to an active energy ray-curable coating agent having a number average molecular weight of the monofunctional (meth) acrylate monomer in the range of 100 to 1000.

Further, in the present invention, the active energy ray-curable coating in which the glass transition temperature (Tg) of the acrylic resin containing the (meth) acryloyl group is in the range of 40 to 130 ° C. and the hydroxyl value is 5 to 300 mgKOH / g. Regarding the agent.

The present invention further relates to an active energy ray-curable coating agent containing a bifunctional or higher functional (meth) acrylate monomer.

The present invention further relates to an active energy ray-curable coating agent containing a silicone epoxy (meth) acrylate.

The present invention also relates to an active energy ray-curable coating agent containing no volatile organic solvent having a boiling point of less than 260 ° C. under normal pressure.

The present invention also relates to a coated building material having a film formed from the active energy ray-curable coating agent.

The active energy ray-curable coating agent of the present invention can provide a coated building material having a matte-like low gloss, excellent printability, and cellophane tape (registered trademark) resistance.

The active energy ray-curable coating agent of the present invention comprises a monofunctional (meth) acrylate monomer, dicyclohexylmethane 4,4'-diisosianate and a hydroxyl group-containing (meth) acrylate as a compound having a plurality of (meth) acryloyl groups. An active energy ray-curable coating agent containing a urethane (meth) acrylate as a reaction product and / or an acrylic resin containing a (meth) acryloyl group having a double bond equivalent of 100 to 1000 g / mol. Active energy ray-curable coating agent according to the following (1) to (3) (1) Monofunctional (meth) acrylate monomer is 10 to 60% by mass of the total amount of the curing component.
(2) Urethane (meth) acrylate, which is a reaction product of dicyclohexylmethane 4,4'-diisocyanate and hydroxyl group-containing (meth) acrylate, is 4 to 30% by mass of the total amount of the cured component.
(3) Acrylic resin containing a (meth) acryloyl group having a double bond equivalent of 100 to 1000 / mol is 0.1 to 20% by mass of the total amount of the cured component.
It is an active energy ray-curable coating agent characterized by being.

In the present invention, the "curing component" is an active energy ray-curing component contained in the active energy ray-curable coating agent of the present invention, specifically, a monofunctional (meth) acrylate monomer, or a plurality of (meth) compounds. As a compound having an acryloyl group, urethane (meth) acrylate, which is a reaction product of dicyclohexylmethane 4,4'-diisocyanate and a hydroxyl group-containing (meth) acrylate, and / or a double bond equivalent of 100 to 1000 / mol. Represents all components of acrylic resin containing (meth) acryloyl group and other active energy ray-curable compounds contained as necessary, and does not contain photopolymerization initiators or active energy ray non-curable compounds. do. Further, the "total amount of cured components" represents the total mass of all the components.

The (meth) acrylate monomer used in the active energy ray-curable coating agent of the present invention will be described.
In the present invention, "(meth) acrylate" means one or both of acrylate and methacrylate.

Examples of the monofunctional (meth) acrylate include ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, lauryl (meth) acrylate, and 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, nonylphenoxyethyl (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 tetrahydroflu Examples thereof include frill (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, and ethoxyethoxyethanol acrylic acid multimer ester.

Of these, the ethoxyethoxyethanol acrylic acid multimer ester is preferable, and specifically, α-acryloyl-ω- (3,6-dioxaoctane-1-yloxy) poly (oxyethylenecarbonyl) is most preferable.

The content of the monofunctional (meth) acrylate is preferably 10 to 60% by mass of the total amount of the curing component in the coating agent, preferably 15 to 55% by mass from the viewpoint of suitable coating property and curability of the coated surface. It is more preferable if it is in the range of%.
When the content of the monofunctional (meth) acrylate is 10% by mass or more of the total amount of the curing component, sufficient low gloss tends to be obtained, and when it is 60% by mass or less, sufficient curability tends to be obtained.

Next, the urethane (meth) acrylate used in the active energy ray-curable coating agent of the present invention will be described. In addition, in this invention, "urethane (meth) acrylate" means one or both of urethane acrylate and urethane methacrylate.
The urethane acrylate used in the active energy ray-curable coating agent of the present invention is essential to be a reaction product of dicyclohexylmethane 4,4'-diisocyanate and a hydroxyl group-containing (meth) acrylate.
Examples of the hydroxyl group-containing (meth) acrylate include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, 1,4-cyclohexanedimethanol monoacrylate, and polyethylene glycol monoacrylate. , Polyethylene glycol monomethacrylate, trimethylolpropane diacrylate, trimethylolpropanedimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, glycidyl acrylate, glycidyl methacrylate and the like. can.

The content of the urethane (meth) acrylate is preferably 4 to 30% by mass of the total amount of the curing component in the coating agent from the viewpoint of suitable coating property and curability of the coated surface, and particularly for paper substrates. It is more preferable if the range is in the range of 5 to 30% by mass from the viewpoint of preventing coating unevenness due to rapid suction.
If the content of urethane (meth) acrylate is 4% by mass or more of the total amount of the cured component in the coating agent, sufficient printing suitability tends to be obtained, and if it is 30% by mass or less, the increase in viscosity is suppressed and the coating property is sufficient. It tends to be retained.

Next, an acrylic resin containing a (meth) acryloyl group having a double bond equivalent of 100 to 1000 g / mol used in the active energy ray-curable coating agent of the present invention will be described.

The acrylic resin containing a (meth) acryloyl group used in the present invention is not particularly limited, and an acrylic resin obtained by a known method can be used.
Specifically, for example, a carboxyl group-containing polymerizable monomer such as acrylic acid or methacrylic acid or an amino group-containing polymerizable monomer such as dimethylaminoethyl methacrylate or dimethylaminopropylacrylamide is previously blended as the copolymerization component. Then, the copolymer having a carboxyl group or an amino group is obtained, and then the carboxyl group or the amino group is reacted with a monomer having a glycidyl group such as glycidyl methacrylate and a (meth) acryloyl group. In advance, a hydroxyl group-containing monomer such as 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate is blended as the copolymerization component and copolymerized to obtain the copolymer having a hydroxyl group, and then the hydroxyl group and isocyanate ethyl are obtained. A method of reacting an isocyanate group such as methacrylate with a monomer having a (meth) acryloyl group. A glycidyl group-containing polymerizable monomer such as glycidyl methacrylate is previously mixed as the copolymerization component and copolymerized to have a glycidyl group. A method of reacting the above-mentioned copolymer with a glycidyl group and a carboxyl group-containing polymerizable monomer of acrylic acid or methacrylic acid, and a copolymer using thioglycolic acid as a chain transfer agent during polymerization. A method of introducing a carboxyl group at the terminal and reacting the carboxyl group with a monomer having a glycidyl group such as glycidyl methacrylate and a (meth) acryloyl group, and a carboxyl such as azobiscyanopentanoic acid as a polymerization initiator. Examples thereof include a method of introducing a carboxyl group into a copolymer using a group-containing azo initiator and reacting the carboxyl group with a glycidyl group such as glycidyl methacrylate and a monomer having a (meth) acryloyl group.

Above all, a carboxyl group-containing monomer such as acrylic acid or methacrylic acid or an amino group-containing monomer such as dimethylaminoethyl methacrylate or dimethylaminopropylacrylamide is copolymerized, and the carboxyl group or amino group and glycidyl methacrylate are obtained. A method of reacting a monomer having a (meth) acryloyl group with a glycidyl group such as, or a glycidyl group-containing polymerizable monomer such as glycidyl methacrylate is previously compounded as the copolymerization component and copolymerized to obtain a glycidyl group. The method of reacting the glycidyl group with a carboxyl group-containing polymerizable monomer of acrylic acid or methacrylic acid is the most convenient and preferable method.

As the monomer component constituting the acrylic resin containing the (meth) acryloyl group used in the present invention, monofunctionals such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene, and N-vinylproridone are used. Monomers and polyfunctional monomers such as trimethylol propane (meth) acrylate, hexanediol (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa. Examples thereof include (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and neopentyl glycol (meth) acrylate.

The double bond equivalent of the acrylic (meth) acrylate resin is indispensable in the range of 100 to 1000 g / mol. When the double bond equivalent of the acrylic (meth) acrylate is 100 g / mol or more, it is possible to suppress an increase in volume shrinkage during curing, and it is difficult for cracking due to bending or strain of the coating film to occur, and processing by dense cross-linking is performed. There is a tendency that the deterioration of sex is unlikely to occur. Further, when it is 1000 g / mol or less, the physical properties such as hardness after the reaction are sufficient without lack of reactive groups, and when it is in the range of 200 to 600 g / mol, it is more preferable, and in the range of 200 to 400 g / mol. If there is, it is more preferable.
The double bond equivalent of the acrylic resin containing the (meth) acryloyl group is defined by the following formula.
"Double bond equivalent" = "Molecular weight of one molecule of acrylic resin containing (meth) acryloyl group" / "Number of double bonds"

The weight average molecular weight of the acrylic resin containing the (meth) acryloyl group is preferably in the range of 10,000 to 100,000. When the weight average molecular weight of the acrylic resin containing the (meth) acryloyl group is 10,000 or more, tack is less likely to remain on the coating film, tack-free only in the drying step is facilitated, and 100,000. If the above is the case, the viscosity of the active energy ray-curable building material paint does not become too high, and it is possible to avoid the problem that the dilution at the time of coating is too effective and a sufficient coating amount cannot be obtained. Further, from the viewpoint of workability, the range of 10,000 to 50,000 is more preferable, and the range of 10,000 to 30,000 is even more preferable.
The weight average molecular weight is measured by GPC in terms of polystyrene.

The content of the acrylic resin containing the (meth) acryloyl group is 0.1 to 20% by mass of the total amount of the curing component in the coating agent, which is suitable for the coating property and the curing property of the coated surface. Therefore, it is more preferable if it is in the range of 0.5 to 20% by mass, particularly from the viewpoint of preventing coating unevenness due to rapid penetration into the paper substrate.
If the content of the acrylic resin containing the (meth) acryloyl group is 0.1% by mass or more of the total amount of the curing component in the coating agent, sufficient printing suitability tends to be obtained, and if it is 20% by mass or less, the viscosity tends to be obtained. The increase is suppressed and the covering property tends to be sufficiently maintained.

Further, the glass transition temperature (Tg) of the acrylic resin containing the (meth) acryloyl group is preferably in the range of 40 to 130 ° C., and if it is 40 ° C. or higher, it is sufficient after curing when the coating film is formed. High strength can be obtained, and if the temperature is 130 ° C. or lower, brittleness appears when the coating film is formed, and the tendency of deterioration of workability can be suppressed. Further, the hydroxyl value of the acrylic (meth) acrylate is preferably in the range of 5 to 300 mgKOH / g, and if it is 5 mgKOH / g or more, the dispersion of the matting agent such as silica used in combination does not decrease and the gloss is lowered. It tends to be easy to hold, and if it is 300 mgKOH / g or less, the tendency to decrease the stain resistance can be suppressed.
The glass transition temperature (Tg) is measured by scanning with a differential scanning calorimeter, a nitrogen atmosphere, a cooling device, a temperature range of -80 to 450 ° C, and a temperature rise temperature of 10 ° C / min. It is a thing.

Further, in the active energy ray-curable coating agent of the present invention, bifunctional or higher (meth) methacrylate may be used in combination in addition to the monofunctional (meth) acrylate monomer. By using a bifunctional or higher (meth) acrylate in combination with the monofunctional (meth) acrylate monomer, higher strength can be obtained as compared with the case where only the monofunctional monomer is used while maintaining the appearance of the coating film. Can be done. Further, a polymerizable oligomer may be used in combination if necessary.

Examples of the bifunctional (meth) acrylate include 1,4-butanediol di (meth) acrylate, 3-methyl-1,5-pentanediol di (meth) acrylate, and 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, tricyclode Candimethanol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, etc. Di (meth) acrylate of dihydric alcohol, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, di (meth) acrylate of tris (2-hydroxyethyl) isocyanurate, 4 in 1 mol of neopentyl glycol. Examples thereof include di (meth) acrylate of a diol obtained by adding a molar or more of ethylene oxide or propylene oxide, and di (meth) acrylate of a diol obtained by adding 2 mol of ethylene oxide or propylene oxide to 1 mol of bisphenol A. Be done.

Examples of the trifunctional or higher (meth) methacrylate include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dimethylolpropane tetra (meth) acrylate, and dipentaerythritol. Poly (meth) acrylates of trihydric polyhydric alcohols such as poly (meth) acrylates, triol tri (meth) acrylates and trimethylol obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of glycerin. Triol di or tri (meth) acrylate obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of propane, and diol obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of bisphenol A. Examples thereof include poly (meth) acrylate of a polyoxyalkylene polyol such as di (meth) acrylate.

Furthermore, a mixture of dipentaerythritol hexaacrylate and dipentaerythritol pentaacrylate, which are bifunctional or higher (meth) acrylates (may be abbreviated as DPHA), dimethylolpropane tetraacrylate (may be abbreviated as DTMPTA), and the like. Trimethylolpropane ethyleneoxide adduct tri (meth) acrylate, which is a tri (meth) acrylate of triol obtained by adding 3 mol or more of ethylene oxide to 1 mol of trimethylolpropane, may be used. Typical examples of the trimethylolpropane ethylene oxide adduct tri (meth) acrylate include trimethylolpropane ethylene oxide (EO) modified (n≈3) triacrylate.
The total amount of the monofunctional (meth) acrylate and the bifunctional or higher (meth) methacrylate described above is preferably in the range of 60 to 80% by mass, more preferably 65 to 75% by mass, based on the total amount of the cured components in the coating agent.

Further, a polymerizable oligomer may be used in combination if necessary. Examples of the polymerizable oligomer include amine-modified polyether acrylates, amine-modified epoxy acrylates, amine-modified aliphatic acrylates, amine-modified polyester acrylates, amine-modified acrylates such as amino (meth) acrylates, polyester (meth) acrylates, and polyether (meth) acrylates. Examples thereof include acrylate, polyolefin (meth) acrylate, polystyrene (meth) acrylate, and epoxy (meth) acrylate.

Amorphous silica is more preferable as the silica used in the active energy ray-curable coating agent of the present invention. Examples of the amorphous silica include diatomaceous earth and active white clay, and among the amorphous silica, dry silica, wet silica, silica gel and the like can be used as the synthetic amorphous silica.
As the silica used as the matting agent used in the coating agent, wet silica produced by neutralization and decomposition reaction of an aqueous solution of sodium silicate with an acid or an alkali metal salt is preferable.

In the synthetic amorphous silica, primary particles of 5 to 55 nm, which are the minimum constituent units of a substance, are fused or chemically bonded to form a primary particle aggregate (secondary particle structure). Furthermore, the primary particle agglomerates physically aggregate and exist as secondary agglomerates. The secondary agglomerates are primary particle agglomerates (secondary particle structure) by applying a physical shearing force in various media. It is possible to disperse up to. The average particle size of the present invention refers to an average secondary particle system which is a primary particle aggregate (secondary particle structure).

The average particle size of the wet silica used as the matting agent is preferably 0.1 to 25 μm, preferably 0.3 to 20 μm, more preferably 0.5 to 15 μm, still more preferably 1 to 10 μm. When the average particle size is less than 0.05 μm, it is composed of strong bonds of primary particles having a smaller particle size and has a large specific surface area, so that it has high oil absorption performance and sufficient flow when used as a coating agent. In addition to not being able to obtain the properties, it is not possible to obtain the high-class feeling that accompanies the matte feeling due to the deterioration of the matte effect. Further, when the average particle diameter is larger than 25 μm, the contamination property is deteriorated due to the dirt entering the unevenness of the surface, and the gloss change / scratch due to the falling / burying of the particles is likely to occur.
The pore volume of the wet silica is preferably 0.1 to 2.0 mL / g, preferably 1.5 to 2.0 mL / g. The apparent specific gravity is preferably 0.1 to 1.5 g / mL, preferably 0.1 to 0.5 g / mL. The oil absorption amount is preferably 50 to 400 mL / 100 g, preferably 100 to 400 mL / 100 g. A sufficient matting effect can be obtained if the pore volume is 0.1 mL / g, the apparent specific gravity is 0.1 g / mL, and the oil absorption amount is 50 mL / 100 g or more. On the contrary, if the pore volume is 2.0 mL / g, the apparent density is 1.5 g / mL, and the oil absorption is 400 mL / 100 g or less, the thickening effect may be increased more than necessary while maintaining the matting effect. It is preferable because it can be suppressed and the fluidity as a coating agent is not impaired.

The content of the wet silica used as the matting agent in the present invention is preferably 0.01 to 20% by mass, more preferably 0.05 to 10% by mass of the total amount of the coating agent. When the silica content is 0.01% by mass or more, a sufficient matting effect can be obtained, and when it is 20% by mass or less, the fluidity and transferability of the coating agent are not impaired, which is preferable. Of these, wet silica having a specific surface area of 50 to 500 m ² / g by the BET method is preferable.

Further, acrylic resin beads, silicone beads, glass beads and the like may be added as the scratch resistance improving additive for imparting scratch resistance. By further adding resin beads as a scratch resistance improving additive to the wet silica as a matting agent, it is possible to improve the scratch resistance of the coated surface in addition to an appropriate low gloss. Of these, acrylic resin beads are preferable.

The average particle size of the beads as the scratch resistance improving additive is 1 to 50 μm, preferably 1 to 30 μm, more preferably 1 to 15 μm, and the content thereof is 3 to 20% by mass of the total amount of the coating agent. Is preferable, and 5 to 15% by mass is more preferable. If the bead content is less than 3% by mass, a sufficient scratch-resistant effect cannot be seen, and if it exceeds 20% by mass, the beads tend to fall off from the surface of the coating film, which is not preferable.

Further, silica may be added as a scratch resistance improving additive that imparts scratch resistance. As the silica added to impart scratch resistance, dry silica produced by burning silicon tetrachloride gas or the like in a gas phase is preferable. By further adding dry silica as a scratch resistance improving additive to the wet silica as a matting agent, it is possible to improve the scratch resistance of the coated surface in addition to an appropriate low gloss. The average particle size of the dry silica as the scratch resistance improving additive is 0.1 to 3 μm, preferably 0.1 to 0.5 μm, and more preferably 0.1 to 0.25 μm, and the content thereof is , 10 to 30% by mass of the total amount of the coating agent is preferable, and 15 to 20% by mass is more preferable. If the silica content is less than 10% by mass, a sufficient scratch-resistant effect cannot be seen, and if it exceeds 30% by mass, the sharpness and stainability as a coating agent tend to be impaired, which is not preferable.
Of these, dry silica having a specific surface area of 50 to 500 m2 / g by the BET method is preferable.

Both the wet silica used as the matting agent and the dry silica used as the scratch resistance improving additive used in the present invention can be surface-modified.
The method for surface-treating the silica particles is not particularly limited and may be any known method. Examples thereof include those treated with a wax or a silane coupling agent for surface difference treatment.

Further, in the active energy ray-curable coating agent of the present invention, by adding inorganic particles and / or organic particles, the cured coating film can be made to have low gloss and more excellent scratch resistance. In addition to the silica, the inorganic particles preferably include talc, nepheline syenzo, mica, bentonite, diatomaceous earth, calcium carbonate, alumina white and the like, and the organic particles include polyethylene wax, polypropylene wax, acrylic bead pigment, or urethane. Bead pigments are preferable, and a plurality of inorganic and organic pigments may be mixed and used without distinction.

Further, in the active energy ray-curable coating agent of the present invention, a silicone (meth) acrylate which is a (meth) acrylate having a silicone skeleton can be added for the purpose of improving cellophane tape (registered trademark) resistance, and among them, silicone. Epoxy (meth) acrylate is preferred.
Commercially available products of the silicone epoxy (meth) acrylate include, for example, Rad2011, Rad2100 (polysiloxane acrylate Cas No .: 125445-52-9), and Rad2500 (poly) of the "Tego (registered trademark)" series manufactured by Ebonic Japan. Dimethylsiloxane acrylate Cas No .: 125445-52-9), Rad2700 (acrylic modified polysiloxane Cas No .: 157811-87-5) and the like can be mentioned, with Rad2700 being particularly preferred.

The amount of the silicone (meth) acrylate added is preferably in the range of 0.1 to 10% by mass, more preferably in the range of 0.3 to 8% by mass, based on the total amount of the coating agent. If it is 0.1% by mass or more, the adhesion of the coating agent to the surface of the coated building material and the cellophane tape (registered trademark) resistance can be maintained. If it is 10% by mass or less, it is possible to suppress the tendency of set-off easily.

A publicly known photopolymerization initiator can be used as the curing agent used in the active energy ray-curable coating agent of the present invention. Among them, a radical polymerization type photopolymerization initiator is preferable, and the active energy ray-curable compound is dissolved. Examples thereof include α-hydroxyalkylketone-based photopolymerization initiators in which the solution is not colored and yellowing is small with time. Examples of the α-hydroxyalkylketone-based photopolymerization initiator include 1-phenyl-2-hydroxy-2-methylpropane-1-one and 1- (4-i-propylphenyl) -2-hydroxy-2-methylpropane. Examples thereof include -1-one, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexylphenyl ketone and the like. Further, a phenylglycolate-based photopolymerization initiator is also preferable. Examples of the phenylglycoxolate-based photopolymerization initiator include methylbenzoylformate and the like. Of these, 1-hydroxycyclohexylphenyl ketone is preferable.

Further, as another radical polymerization type photopolymerization initiator, a monoacylphosphine oxide-based photopolymerization initiator having an absorption wavelength in a long wavelength region among ultraviolet rays may be appropriately used in combination. As monoacylphosphinoxide-based photopolymerization initiators, 2,4,6-trimethylbenzoyl-diphenylphosphinoxide, 2,6, excluding bisacylphosphinoxides that are colored when dissolved in active energy ray-curable compounds. -Dimethoxybenzoyl-diphenylphosphine oxide, 2,6-dichlorobenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-phenylphosphinic acid methyl ester, 2-methylbenzoyl-diphenylphosphine oxide, pivaloyl Examples thereof include monoacylphosphine oxides such as phenylphosphinic acid isopropyl ester, and among these, 2,4,6-trimethylbenzoyl-diphenylphosphinoxide has a UV-with an emission wavelength of 385 nm or 395 nm. Having a UV absorption wavelength that matches the emission wavelength region of the LED is more preferable in that suitable curability can be obtained and yellowing of the cured film is small.

The above-mentioned photopolymerization initiators 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 0.1 to 20% by mass with respect to the total amount of the coating agent. If it is 0.1% by mass or more, good curability can be obtained, and if it is 20% by mass or less, the amount of the initiator does not become excessive, and the fluidity as a coating agent can be maintained, and workability and workability can be maintained. Does not decrease.

Further, the curing rate can be increased by adding a tertiary amine compound selected from an aliphatic amine derivative and / or a benzoic acid amine derivative as a sensitizer. The tertiary amine compound is known to enhance reactivity and prevent reaction inhibition by oxygen. Suitable tertiary amine compounds include, for example, free alkylamines such as triethylamine, methyldiethanolamine, triethanolamine, aromatic amines such as 2-ethylhexyl-4-dimethylaminobenzoate, ethyl-4-dimethylaminobenzoate, and polymers. Active energy ray-polymerizable compounds such as sex unsaturated amines (eg, (meth) acrylated amines) have low odor, low volatility, and reduced yellowing due to their ability to be incorporated into the polymer matrix by curing. It is preferable because of its properties.

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 containing the organic solvent.

Further, as an arbitrary component, a wax, a plasticizer, a dispersant, a defoaming agent and the like can be contained, if necessary.

The active energy ray-curable coating agent of the present invention does not contain a highly volatile organic compound (VVOC) having a boiling point of 50 ° C. or lower and a volatile organic compound (VOC) having a boiling point of 50 to 260 ° C. under normal pressure. Is more preferable.
The purpose is to drastically reduce the amount of organic solvent evaporated into the atmosphere, that is, to reduce VOC, and the following organic solvents such as aromatic hydrocarbons such as toluene and xylene, n-hexane, cyclohexane, etc. Fat group or alicyclic hydrocarbons, esters such as ethyl acetate, butyl acetate, propyl acetate, alcohols such as methanol, ethanol and isopropyl alcohol, ketones such as acetone and methyl ethyl ketone, ethylene glycol monoethyl ether and propylene glycol. It is preferable that it does not contain any of alkylene glycol monoalkyl ethers such as monomethyl ethers.

(Manufacturing of active energy ray-curable coating agent)
The active energy ray-curable coating agent of the present invention has a urethane (meth) acrylate, which is a reaction product of dicyclohexylmethane 4,4'-diisosianate and a hydroxyl group-containing (meth) acrylate, and / or a double bond equivalent. Acrylic (meth) acrylate with 100 to 1000 g / mol and weight average molecular weight of 10,000 to 100,000, monofunctional or bifunctional or higher acrylic resin, photopolymerization initiator, silica, and silicone epoxy (meth) if necessary. It can be produced by mixing and dispersing acrylate, wax and other various additives.

The active energy ray-curable coating agent of the present invention can be adjusted by appropriately adjusting the size of the pulverized media of the disperser, the filling rate of the pulverized media, the dispersion treatment time, and the like. As the disperser, commonly used examples such as a roller mill, a ball mill, a pebble mill, an attritor, and a sand mill can be used.
If the coating agent contains air bubbles or unexpectedly coarse particles, it is preferable to remove them by filtration or the like in order to deteriorate the quality of the coated material. As the filter, a conventionally known one can be used.

Examples of the base material to which the active energy ray-curable coating agent of the present invention is used include paper and various films for decorative sheets, as well as wood and non-combustible materials.
In particular, the active energy ray-curable coating agent of the present invention can obtain good printability with more uniform coating by suppressing rapid permeability into the paper substrate.

The decorative sheet is a pattern obtained by printing or applying known, for example, acrylic, cellulose, vinyl, chlorinated polyolefin, rubber chloride, urethane printing inks or paints to a base material such as paper or film. After forming the layer, the top coat layer for covering the pattern layer is provided, and the active energy ray-curable coating agent of the present invention forms the top coat layer.
Examples of the type of the base material for the decorative sheet include paper quality sheets such as thin paper, plain paper, reinforced paper, and resin-impregnated paper, titanium paper, polyethylene terephthalate sheet, glycol-modified polyethylene terephthalate sheet (PETG sheet), and polyvinyl chloride sheet. , Polyethylene sheet, acrylic nitrile butadiene styrene sheet, resin sheet such as polypropylene sheet, composite sheet thereof and the like can be used.
Examples of the wood base material of the wood decorative board include known ones such as plywood, particle board, hard board, and MDF, which have been conventionally used as wood base materials for decorative boards, furniture, building members, and the like. Further, it does not matter what kind of manufacturing method these known substrates are obtained.

Further, examples of the non-combustible material that can be used as a base material include gypsum board, gypsum board, perforated board building material made of calcium silicate board and the like.

Taking a decorative sheet using the active energy ray-curable coating agent of the present invention as an example, for example, acrylic-based, cellulose-based, vinyl-based, chlorinated polyolefin-based, rubber chloride-based, and urethane-based, which are known on the substrate. After forming a pattern layer by printing or applying printing ink or paint, the active energy ray-curable coating agent is applied, and a painted building material is manufactured through a step of producing a coating film of the coating agent.

In producing a coating film using the active energy ray-curable coating agent, specific examples of the coating / printing method of the building material paint include, for example, a roll coater, a gravure coater, a flexographic coater, and an air coating method. A doctor coater, a blade coater, an air knife coater, a squeeze coater, an impregnation coater, a transfer roll coater, a kiss coater, a curtain coater, a cast coater, a spray coater, a die coater, an offset printing machine, a screen printing machine and the like can be appropriately adopted.

Next, by irradiating the coating film obtained in the above step with an active energy ray of 30 to 1000 mJ / cm ² at least once, it is possible to provide a coated building material having excellent surface curability.
By injecting one or more mixed gases selected from nitrogen gas, carbon dioxide gas, and argon gas into the reaction vessel together with air or alone, the active energy can be reduced to an oxygen concentration of less than 8% in a gas atmosphere. If the linear curable coating agent can be irradiated with active energy rays, the curability of the coating film obtained in the above step can be promoted more efficiently.

The active energy rays of 30 to 1000 mJ / cm ² are ultraviolet rays, electron beams, γ-rays, ionizing radiation, electromagnetic waves, and the like, and among them, ultraviolet rays or electron beams are preferable.

When irradiating ultraviolet rays in a gas atmosphere having an oxygen concentration of less than 8%, a known ultraviolet irradiation device equipped with a high-pressure mercury lamp, an excimer lamp, a metal halide lamp, or the like can be used. When the amount of ultraviolet light during curing is 30 mJ / cm ² or more, the curing efficiency is good, and when it is 1000 mJ / cm ² or less, it is preferable from the viewpoint of preventing damage to the substrate due to heat.

The active energy ray-curable coating agent of the present invention can be formed into a cured film by irradiating the substrate with active energy rays after coating the substrate. The active energy rays are ionized radiation such as ultraviolet rays, electron beams, α rays, β rays, and γ rays, but specific energy sources or curing devices include, for example, sterilizing lamps and fluorescent lamps for ultraviolet rays. Ultraviolet light emitting diode (UV-LED), carbon arc, metal halide lamp, xenon lamp, chemical lamp, low pressure mercury lamp, high pressure mercury lamp for copying, medium pressure or high pressure mercury lamp, ultra high pressure mercury lamp, electrodeless lamp, metal halide lamp, natural light, etc. Examples thereof include ultraviolet rays as a light source, or electron beams produced by a scanning type or curtain type electron beam accelerator.
In the active energy ray-curable coating agent of the present invention, by irradiating with light such as active energy rays, preferably ultraviolet rays, as described above, a curing reaction is carried out without leaving stickiness in the finish even if it is not a two-component curing type. I can do things. For example, a commercially available lamp such as an H lamp, a D lamp, or a V lamp manufactured by Fusion Systems can be used.

In curing in an inert gas, curing inhibition by oxygen is small, and urethane (meth) acrylate, which is a reaction product of the above-mentioned dicyclohexylmethane 4,4'-diisosianate and a hydroxyl group-containing acrylate, and / or a double bond. The reaction of the radically polymerizable double bond of the main agent, such as acrylic (meth) acrylate having an equivalent amount of 100 to 1000 g / mol and a weight average molecular weight of 10,000 to 100,000, is further advanced, and the curing is sufficiently performed, and the time is long. Since it remains on the surface layer for a long period of time even after the lapse of time, the resistance of the coating surface of the decorative sheet is increased, and the adhesion can be further improved. The sufficiently fixed additive component does not easily come off even if it comes into contact with the back surface of the original fabric, for example, in winding a roll in gravure printing.

Further, the active energy ray-curable coating agent of the present invention can be widely applied not only to building materials but also to surface coating applications such as furniture, musical instruments, office supplies, sports goods and toys.

Hereinafter, the present invention will be described in more detail by way of examples. In addition, the part and the mass part in the following Examples represent mass%.
The weight average molecular weight (polystyrene equivalent) was measured by GPC in the present invention using the HLC8220 system manufactured by Tosoh Corporation under the following conditions.
Separation column: Uses 4 TSKgelGMHR-N manufactured by Tosoh Corporation.
Column temperature: 40 ° C.
Moving layer: Tetrahydrofuran manufactured by Wako Pure Chemical Industries, Ltd.
Flow rate: 1.0 ml / min.
Sample concentration: 1.0% by weight.
Sample injection volume: 100 microliters.
Detector: Differential refractometer.

The glass transition temperature (Tg) is measured by using a differential scanning calorimeter (“DSC Q100” manufactured by TA Instruments Co., Ltd.) in a nitrogen atmosphere and using a cooling device to raise the temperature in the temperature range of -80 to 450 ° C. The scanning was performed under the condition of a temperature of 10 ° C./min.

The hydroxyl value of acrylic (meth) acrylate is the amount of hydroxyl group in 1 g of resin calculated by back-titling the residual acid with alkali when the hydroxyl group in the resin is acetylated with an excess acetyl reagent. It is shown by the number of mg of potassium oxide (KOH), and is based on JIS K0070.

The average particle size of silica was measured using a nanoparticle particle size distribution measuring device Nanotrac UPA EX-150 manufactured by Nikkiso Co., Ltd.

(Adjustment of active energy ray-curable coating agent)
[Example 1]
Urethane (meth) acrylate (number average molecular weight: 5000), which is the reaction product of dicyclohexylmethane 4,4'-diisosianate and hydroxyl group-containing (meth) acrylate, 2 parts, ethoxyethoxyethanol acrylic acid multimer as monofunctional acrylate 16.6 parts of α-acryloyl-ω- (3,6-dioxaoctane-1-yloxy) poly (oxyethylenecarbonyl) (Cas. No 188746-52-3), which is an ester, and hexane, which is a bifunctional acrylate. 16.6 parts of diol ethylene oxide modified diacrylate Miramer M202 (manufactured by MIWON) 16.6 parts of tripropylene glycol diacrylate Miramer M220 (manufactured by MIWON) which is a bifunctional acrylate Trimethylol propane which is a trifunctional acrylate Ethylene oxide-modified triacrylate, 20.8 parts of M3130 manufactured by MIWON, 8.3 parts of 1-hydroxy-cyclohexyl-phenyl-ketone "Omnirad 184" manufactured by BASF, Nipseal E170 (average particle size: 3 μm, east) which is a wet silica. 8.3 parts of Seo Silica Co., Ltd.), 5 parts of Minex 8F (manufactured by Shiraishi Kogyo Co., Ltd.), which is a sodium potassium aluminum silicate, and Lancowax PP1362D (average particle size 6 μm, Nippon Lubrisol), which is a polypropylene wax. 3.3 parts of (manufactured by Co., Ltd.) and 0.2 parts of the defoaming agent BYK A501 (manufactured by Big Chemie Japan), totaling 99.9 parts, were stirred and mixed with a stirrer for 1 hour, and then stirred with a bead mill for 2 hours. , Active energy ray-curable coating agent 1 was prepared.

(Adjustment of active energy ray-curable coating agent)
[Examples 2 to 19, Comparative Examples 1 to 11]
According to the formulations shown in Tables 1 to 3, each active energy ray-curable coating agent was prepared by the same procedure as in Example 1.
As an acrylic resin containing a (meth) acryloyl group, acrylic acrylate resin A (double bond equivalent 250 g / mol product, weight average molecular weight 25,000, Tg 56 ° C., hydroxyl value 113 mgKOH / g), acrylic acrylate resin B ( Double bond equivalent 360 g / mol product, weight average molecular weight 25,000, Tg73 ° C, hydroxyl value 78 mgKOH / g), acrylic acrylate resin C (double bond equivalent 550 product g / mol product, weight average molecular weight 25,000, Tg85) 3 types of ° C. and hydroxyl value 50 mgKOH / g) were used.
Further, as the dipentaerythritol pentaacrylate mixture (DPHA), Miramer M600 (manufactured by MIWON) was used.
For Examples 16 and 17, 1.2 parts of TEGORAD2700 (acrylic modified polysiloxane Cas No .: 157811-87-5, manufactured by Evonik Japan Co., Ltd.) was added as a release agent.
Further, in Example 18, 20 parts of acrylic resin beads GM-0801 (average particle diameter 8 μm, manufactured by Aica Kogyo Co., Ltd.) were added for the purpose of further improving the scratch resistance.

<Making a decorative sheet>
A solid black printing paper (thickness 40 μm) is used as a base material, and the active energy ray-curable coating agents prepared in Examples 1 to 17 and Comparative Examples 1 to 11 are applied by using a bar coater (4 μm). After that, ultraviolet irradiation with a high-pressure mercury lamp was performed once to cure the coating film. Using an air-cooled high-pressure mercury lamp (output 120 W / cm 1 lamp) and a UV irradiation device (GS Yuasa Corporation) equipped with a belt conveyor, the coated material is placed on the conveyor and the speed is directly under the lamp (irradiation distance 11 cm) per minute. The building material paint was cured by passing it at a speed of 25 meters.
It was confirmed that the ultraviolet irradiation amount was 40 mJ / cm2 using an ultraviolet integrated photometer (industrial UV checker UVR-N1 manufactured by GS Yuasa Corporation).

〔Evaluation methods〕
The evaluation method of the active energy ray curable coating agent of this invention is shown.

[Evaluation item 1: Low gloss]
The gloss (gloss) value of each of the prepared decorative sheet surfaces after UV curing was measured using a gloss meter VG2000 manufactured by Nippon Denshoku, and evaluated in the following three stages.
The gloss measurement conditions were an incident angle of 60 ° and a reflection angle of 60 °.
(Evaluation criteria)
◯: The gross value at 60 degrees is less than 15.
Δ: The gloss value at 60 degrees is 15 or more and less than 30.
X: The gloss value at 60 degrees is 30 or more.

[Evaluation item 2: Printability]
The state of the coating film about 10 seconds after being coated on the paper substrate was visually evaluated in the following four stages.
(Evaluation criteria)
⊚: Penetrates evenly and has no uneven coating.
◯: Slight coating unevenness can be seen.
Δ: Uneven coating is visible, but it is a usable level.
X: Penetration into the paper substrate is quick, and coating unevenness is remarkable.

[Evaluation item 3: Cellotape resistance (registered trademark)]
Assuming temporary fixing with notices such as memos when actually processing the decorative sheet at the construction site and tapes for alignment, a coating agent curing film on the surface of the decorative sheet using black solid paper as the base material The cellophane tape was attached to the surface and rapidly peeled off 10 times, and the appearance of the printed film was evaluated in the following three stages.
(Evaluation criteria)
◯: No peeling of the printed film was observed.
Δ: 70% or more of the print film remained on the black solid paper in the area ratio ×: Less than 70% of the print film remained on the black solid paper in the area ratio.

[Evaluation item 4: Scratch resistance]
The scratch resistance of the surface of the decorative sheet was rubbed with a nail on the surface of the coating film, and the degree of scratching was visually evaluated in the following three stages.
◯: No change is seen.
Δ: There are shallow and slight scratches on the tested part.
X: There is a clear deep scratch on the tested part.

Tables 1 to 3 show the evaluation results of the decorative sheet using each active energy ray-curable coating agent.
The values in the table are all parts by mass or% by mass. Blank indicates that it is not mixed.

The decorative sheet using the active energy ray-curable coating agent of the present invention has matte-like low gloss, excellent printability without uneven coating, and cellophane tape (registered trademark) without using an organic solvent. is doing.
Further, the addition of acrylic resin beads resulted in further improvement in scratch resistance on the surface of the decorative sheet.

Claims (7)

A monofunctional (meth) acrylate monomer as a curing component, and a reaction product of dicyclohexylmethane 4,4'-diisocyanate as a compound having a plurality of (meth) acryloyl groups and a hydroxyl group-containing (meth) acrylate, urethane (meth). An active energy ray-curable coating agent containing an acrylate and / or an acrylic resin containing a (meth) acryloyl group having a double bond equivalent of 100 to 1000 / mol.
(1) Monofunctional (meth) acrylate monomer is 10 to 60% by mass of the total amount of the cured component.
(2) Urethane (meth) acrylate, which is a reaction product of dicyclohexylmethane 4,4'-diisocyanate and hydroxyl group-containing (meth) acrylate, is 4 to 30% by mass of the total amount of the cured component.
(3) Acrylic resin containing a (meth) acryloyl group having a double bond equivalent of 100 to 1000 / mol is 0.1 to 20% by mass of the total amount of the cured component.
An active energy ray-curable coating agent characterized by being.
The active energy ray-curable coating agent according to claim 1, wherein the monofunctional (meth) acrylate monomer has a number average molecular weight in the range of 100 to 1000.
The active energy ray according to claim 1 or 2, wherein the acrylic resin containing the (meth) acryloyl group has a glass transition temperature (Tg) in the range of 40 to 130 ° C. and a hydroxyl value of 5 to 300 mgKOH / g. Curable coating agent.
The active energy ray-curable coating agent according to any one of claims 1 to 3, further comprising a bifunctional or higher functional (meth) acrylate monomer.
The active energy ray-curable coating agent according to any one of claims 1 to 4, further comprising a silicone epoxy (meth) acrylate.
The active energy ray-curable coating agent according to any one of claims 1 to 5, which does not contain a volatile organic solvent having a boiling point of less than 260 ° C. under normal pressure.
A coated building material having a film formed from the active energy ray-curable coating agent according to claims 1 to 6.