JP6225375B2 - Active energy ray curable composition, active energy ray curable paint, and article coated with the paint - Google Patents

Description

  The present invention relates to an active energy ray-curable composition, an active energy ray-curable coating material, and an article coated with the coating material, from which a cured coating film excellent in appearance, scratch resistance, substrate adhesion and hot water resistance is obtained.

  Active energy ray curable compositions are used as hard coating agents for plastic substrates for home appliances, mobile phones, etc., because they have a low heat history on the coating substrate and excellent coating film hardness and scratch resistance. . In order to improve the scratch resistance, these active energy ray-curable compositions are devised to increase the crosslinking density by introducing a large amount of (meth) acryloyl groups, but in general, if there are many (meth) acryloyl groups There was a tendency for rapid volume shrinkage to occur at the time of curing, and the adhesiveness with the base material tended to deteriorate.

  A curable resin composition in which an acrylic resin and an ultraviolet curable composition are blended has been studied for this adhesion problem (for example, Patent Document 1). In this curable resin composition, the acrylic resin is selected from 2-ethylhexyl (meth) acrylate, n-butyl (meth) acrylate, n-stearyl (meth) acrylate, and lauryl (meth) acrylate ( (Meth) acrylic acid ester polymer obtained from a monomer containing a methacrylic acid ester is used to improve adhesion to the base material and topcoat layer, but with a one-coat specification with excellent workability In order to utilize, there existed a problem that the coating-film external appearance was inadequate.

  Therefore, there has been a demand for an active energy ray-curable resin composition capable of obtaining a cured coating film having excellent appearance, scratch resistance, and substrate adhesion.

JP 2009-84309 A

  The problem to be solved by the present invention is an active energy ray curable composition, an active energy ray curable coating, and a coating material that can provide a cured coating film having excellent appearance, scratch resistance, substrate adhesion and hot water resistance. It is to provide a painted article.

  As a result of intensive studies to solve the above problems, the present inventors have obtained an acrylic resin having a specific solubility parameter obtained by copolymerization using a specific acrylic monomer as an essential raw material, and urethane (meta ) By using an active energy ray-curable resin composition containing an acrylate composition, it was found that a cured coating film excellent in appearance, scratch resistance, substrate adhesion and hot water resistance was obtained, and the present invention was completed. did.

  That is, the present invention has an acrylic monomer (a1) having a hydroxyl group, an acrylic monomer (a2) having an alkyl group having 12 to 18 carbon atoms, and an alkyl group having 1 to 4 carbon atoms. An active energy ray-curable resin composition comprising an acrylic resin (A) obtained by copolymerizing an acrylic monomer (a3) as an essential raw material, and a urethane (meth) acrylate composition (B). The solubility parameter of the acrylic resin (A) is 9.4 to 11.5, the active energy ray-curable resin composition, the active energy ray-curable paint, and the paint applied with the paint It relates to goods.

  The active energy ray-curable composition of the present invention is useful as an active energy ray-curable coating because a cured coating film excellent in appearance, scratch resistance, substrate adhesion and hot water resistance is obtained. Can be painted on various articles. Therefore, the active energy ray-curable resin composition of the present invention is a housing for home appliances such as a television, a refrigerator, a washing machine, and an air conditioner; a housing for an electronic device such as a personal computer, a smartphone, a mobile phone, a digital camera, and a game machine. Interior materials for various vehicles such as automobiles and railway vehicles, and can be suitably used for paints for coating articles such as FRP bathtubs.

  The active energy ray-curable resin composition of the present invention includes an acrylic monomer (a1) having a hydroxyl group, an acrylic monomer (a2) having an alkyl group having 12 to 18 carbon atoms, and 1 carbon atom. Active energy ray curing containing acrylic resin (A) obtained by copolymerizing acrylic monomer (a3) having ˜4 alkyl groups as essential raw material and urethane (meth) acrylate composition (B) The acrylic resin (A) has a solubility parameter of 9.4 to 11.5.

  In the present invention, “(meth) acryloyl” refers to one or both of acryloyl and methacryloyl groups, “(meth) acrylate” refers to one or both of acrylate and methacrylate, and “(meth) acrylic” “Acid” refers to one or both of acrylic acid and methacrylic acid.

In the present invention, the unit of the solubility parameter is (cal / ml) ^1/2 .

  First, the acrylic resin (A) will be described. This acrylic resin (A) includes an acrylic monomer (a1) having a hydroxyl group, an acrylic monomer (a2) having an alkyl group having 12 to 18 carbon atoms, and an alkyl group having 1 to 4 carbon atoms. It is obtained by copolymerizing an acrylic monomer (a3) having an essential raw material.

  Examples of the acrylic monomer (a1) having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxy-n-butyl (meth) acrylate, and 2-hydroxypropyl. (Meth) acrylate, 2-hydroxy-n-butyl (meth) acrylate, 3-hydroxy-n-butyl (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, N- (2-hydroxyethyl) (Meth) acrylamide, glycerin mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2- (meth) acryloyloxy Ethyl-2-hydroxyethyl phthalate, lactone-modified (meth) acrylate having a hydroxyl group at the terminal. In addition, the acrylic monomer (a1) having these hydroxyl groups can be used alone or in combination of two or more.

  Examples of the acrylic monomer (a2) having an alkyl group having 12 to 18 carbon atoms include lauryl (meth) acrylate, tridecyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, and the like. Among these, lauryl methacrylate and tridecyl methacrylate are preferable because the hot water resistance of the obtained coating film is improved. These acrylic monomers (a2) can be used alone or in combination of two or more.

  Examples of the acrylic monomer (a3) having an alkyl group having 1 to 4 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and iso-propyl (meth). ) Acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate and the like. These acrylic monomers (a3) can be used alone or in combination of two or more.

  Furthermore, as a raw material of the acrylic resin (A), the other essential monomers (a4) other than the acrylic monomer (a1), the acrylic monomer (a2), and the acrylic monomer (a3) which are the essential raw materials described above. ) May be used. Examples of the other monomer (a4) include (meth) acrylic acid, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, and 2-ethylhexyl (meth). Acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, acrylamide, N, N-dimethyl (meth) acrylamide, (meth) acrylonitrile, 3- (meth) acryloylpropyl Examples include trimethoxysilane, 2-dimethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, styrene, α-methylstyrene, p-methylstyrene, and p-methoxystyrene. These can be used alone or in combination of two or more.

  Since the compatibility with the urethane (meth) acrylate (B) is improved, the amount of the acrylic monomer (a1) used is 5 to 5 in the monomer component that is a raw material of the acrylic resin (A). The range of 40% by mass is preferable, and the range of 8 to 25% by mass is more preferable. The amount of the acrylic monomer (a2) used is preferably in the range of 5 to 60% by mass in the monomer component that is the raw material of the acrylic resin (A) because the adhesion after the water resistance test is improved. The range of 20-35 mass% is more preferable. The amount of the acrylic monomer (a3) used is in the range of 5 to 90% by mass in the monomer component that is the raw material of the acrylic resin (A) because the adhesion to the plastic substrate is improved. Preferably, the range of 40 to 72 mass% is more preferable. In addition, the usage-amount of the said other monomer (a4) is said acrylic monomer (a1) and acrylic monomer from the total 100 mass% of the monomer component which is a raw material of the said acrylic resin (A). It becomes the remainder except the use ratio of (a2) and the acrylic monomer (a3).

  The acrylic resin (A) is produced by a known polymerization method using the acrylic monomers (a1) to (a3) and, if necessary, other monomers (a4) as raw materials. However, the solution radical polymerization method is preferable because it is the simplest.

  The solution radical polymerization method is a method in which each monomer as a raw material is dissolved in a solvent and a polymerization reaction is performed in the presence of a polymerization initiator. Examples of the solvent that can be used in this case include hydrocarbon solvents such as toluene, xylene, cyclohexane, n-hexane, and octane; methanol, ethanol, iso-propanol, n-butanol, iso-butanol, sec-butanol. Alcohol solvents such as ethylene glycol monomethyl ether; ester solvents such as methyl acetate, ethyl acetate, n-butyl acetate, isobutyl acetate, amyl acetate; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone It is done. These solvents can be used alone or in combination of two or more.

  Examples of the polymerization initiator used in the production of the acrylic resin (A) include 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2-methylbutyronitrile), azobiscyanovaleric acid, and the like. Tert-butyl peroxypivalate, tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, di-tert-butyl peroxide, cumene hydroperoxide, benzoyl peroxide, tert -Organic peroxides such as butyl hydroperoxide; inorganic peroxides such as hydrogen peroxide, ammonium persulfate, potassium persulfate, and sodium persulfate. These polymer initiators can be used alone or in combination of two or more. Moreover, it is preferable to use the said polymerization initiator within the range of 0.1-10 mass% with respect to the sum total of the monomer used as the raw material of the said acrylic resin (A).

  In addition to the polymerization initiator, a chain transfer agent such as lauryl mercaptan, octyl mercaptan, 2-mercaptoethanol, octyl thioglycolate, 3-mercaptopropionic acid, α-methylstyrene dimer or the like may be used as necessary. it can.

  The solubility parameter of the acrylic resin (A) is in the range of 9.7 to 11.5 because the compatibility with the urethane (meth) acrylate (B) is improved and the appearance of the resulting coating film is more excellent. Is preferable, and the range of 9.8 to 11.0 is more preferable.

In the present invention, the solubility parameter of the acrylic resin (hereinafter abbreviated as “SP”) is
SP (δ) = (ΔE / V) ^1/2
(ΔE: molecular cohesive energy (cal / mol), V: molecular volume (ml / mol))
Is obtained by the following turbidity titration method based on the above formula.
"Calculation formula of SP by turbidity titration method"
VmL ^1/2 (δ−δmL) ≈VmH ^1/2 (δmH−δ)
δ = (VmL ^1/2 δmL + VmH ^1/2 δmH) / (VmL ^1/2 + VmH ^1/2 )
δ: SP of acrylic resin (cal / ml) ^1/2 )
VmL: low polar solvent molecular volume with low SP (ml / mol)
VmH: Molecular volume of high polar solvent with high SP (ml / mol)
δmL: SP of low polarity solvent with low SP ((cal / ml) ^1/2 )
δmH: SP of high polarity solvent with high SP ((cal / ml) ^1/2 )
"Titration method"
Weigh 0.500 g of acrylic resin into a 50 ml Erlenmeyer flask. To this, 10 ml of tetrahydrofuran as a dissolving solvent was added to completely dissolve the acrylic resin, and then normal hexane (low polarity solvent) was dropped while maintaining the temperature at 25 ° C., and the turbidity titration (ml) was measured. The turbid drip quantification (ml) in ion-exchanged water (high polarity solvent) is measured in the same procedure. The 50 ml Erlenmeyer flask being titrated was placed on a printed material (10-point type) while being kept at 25 ° C., and when looking into the 50 ml Erlenmeyer flask from above, the printed material (see below) was prepared under the Erlenmeyer flask through the liquid layer. The end point is the point at which the 10-point type) becomes cloudy and blurry. In addition, 25 degreeC SP of tetrahydrofuran, normal hexane, and ion-exchange water uses the following values.
Molecular volume of tetrahydrofuran: 81 (ml / mol)
Molecular volume of normal hexane (VmL): 132 (ml / mol)
Molecular volume of ion-exchanged water (VmH): 18 (ml / mol)
Tetrahydrofuran SP: 9.52 ((cal / ml) ^1/2 )
Normal hexane SP (δ mL): 7.24 ((cal / ml) ^1/2 )
SP (δmH) of ion-exchanged water: 23.50 ((cal / ml) ^1/2 )

  The hydroxyl value of the acrylic resin (A) is preferably 40 to 150 mgKOH / g, and preferably 60 to 120 mgKOH / g because the appearance, scratch resistance, substrate adhesion, and hot water resistance of the resulting coating film are improved. A range is more preferred.

  In the present invention, the hydroxyl value is measured in accordance with JIS test method K 0070-1992.

  The weight average molecular weight (Mw) of the acrylic resin (A) is preferably in the range of 5,000 to 100,000, more preferably in the range of 8,000 to 50,000, and in the range of 15,000 to 25,000. Further preferred. Here, the weight average molecular weight (Mw) is a value converted to polystyrene based on gel permeation chromatography (hereinafter abbreviated as “GPC”) measurement. The measurement conditions for GPC are as follows.

[GPC measurement conditions]
Measuring device: High-speed GPC device (“HLC-8220GPC” manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series.
"TSKgel G5000" (7.8 mm ID x 30 cm) x 1 "TSKgel G4000" (7.8 mm ID x 30 cm) x 1 "TSKgel G3000" (7.8 mm ID x 30 cm) x 1 “TSKgel G2000” (7.8 mm ID × 30 cm) × 1 detector: RI (differential refractometer)
Column temperature: 40 ° C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL / min Injection amount: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4 mass%)
Standard sample: A calibration curve was prepared using the following standard polystyrene.

(Standard polystyrene)
"TSKgel standard polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-2500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-5000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-550" manufactured by Tosoh Corporation

  The urethane (meth) acrylate (B) will be described. Examples of the method for producing the urethane (meth) acrylate (B) include a method in which a compound having a hydroxyl group and a (meth) acryloyl group is reacted with a polyisocyanate compound.

  Examples of the compound having a hydroxyl group and a (meth) acryloyl group include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxy-n-butyl (meth) acrylate, and 2-hydroxypropyl. (Meth) acrylate, 2-hydroxy-n-butyl (meth) acrylate, 3-hydroxy-n-butyl (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, N- (2-hydroxyethyl) (Meth) acrylamide, glycerin mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2- (meth) acryl Monofunctional (meth) acrylate having a hydroxyl group such as yloxyethyl-2-hydroxyethylphthalate, lactone-modified (meth) acrylate having a hydroxyl group at the terminal; trimethylolpropane di (meth) acrylate, isocyanuric acid EO-modified diacrylate, penta Examples thereof include polyfunctional (meth) acrylates having a hydroxyl group such as erythritol tri (meth) acrylate and dipentaerythritol penta (meth) acrylate, and among these, it is obtained from the obtained active energy ray-curable resin composition. Pentaerythritol triacrylate and dipentaerythritol pentaacrylate are preferred because they improve the scratch resistance of the cured coating film. These compounds having a hydroxyl group and a (meth) acryloyl group can be used alone or in combination of two or more.

  Examples of the polyisocyanate compound include aromatic diisocyanate compounds such as tolylene diisocyanate, diphenylmethane diisocyanate, m-xylylene diisocyanate, m-phenylenebis (dimethylmethylene) diisocyanate; hexamethylene diisocyanate, lysine diisocyanate, 1,3-bis. (Isocyanatomethyl) aliphatic or fat such as cyclohexane, 2-methyl-1,3-diisocyanatocyclohexane, 2-methyl-1,5-diisocyanatocyclohexane, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate And cyclic diisocyanate compounds.

  Further, as the polyisocyanate compound, a prepolymer having an isocyanate group obtained by addition reaction of the diisocyanate compound with a polyhydric alcohol; a compound having an isocyanurate ring obtained by cyclization and trimerization of the diisocyanate compound; A polyisocyanate compound having a urea bond or a burette bond obtained by reacting the above diisocyanate compound with water can also be used.

  Among the above polyisocyanate compounds, aliphatic or alicyclic diisocyanate compounds are preferable because of excellent yellowing resistance.

  The above polyisocyanate compounds can be used alone or in combination of two or more.

  In addition, said urethanation reaction can be performed by a well-known method.

  The concentration of the (meth) acryloyl group of the urethane (meth) acrylate (B) is preferably in the range of 4 to 11 mmol / g, more preferably in the range of 5 to 10 mmol / g because the scratch resistance is improved.

  The active energy ray-curable resin composition of the present invention contains the acrylic resin (A) and the urethane (meth) acrylate (B), but the acrylic resin (A) and the urethane (meth). The mass ratio [(A) / (B)] with the acrylate (B) is preferably in the range of 10/90 to 70/30 because the scratch resistance and hot water resistance of the resulting coating film are improved. The range of 90-60 / 40 is more preferable.

  The active energy ray-curable aqueous resin composition of the present invention contains the acrylic resin (A) and the urethane (meth) acrylate (B). ) An acrylate (C) may be contained.

Examples of the polyfunctional (meth) acrylate compound (C) include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and propylene glycol. Di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,3-butanediol di (meth) ) Acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, hydroxypivalate ester neopentyl glycol di (me ) Acrylate, bisphenol A-di (meth) acrylate, bisphenol A-EO modified di (meth) acrylate, isocyanuric acid EO modified diacrylate, isocyanuric acid EO modified triacrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane EO Modified tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate and the like can be mentioned, among these, Since the scratch resistance of the cured coating film obtained from the obtained active energy ray-curable resin composition is improved, pentaerythritol triacrylate, pentaerythritol Lumpur tetraacrylate, isocyanuric acid EO-modified triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate are preferable. In addition, these polyfunctional (meth) acrylate compounds (C) can be used alone or in combination of two or more.

  The content of the polyfunctional (meth) acrylate compound (C) in the active energy ray-curable resin composition of the present invention improves the scratch resistance of the resulting coating film, so that the acrylic resin (A), It is preferable that it is 50 mass parts or less with respect to 100 mass parts in total with the said urethane (meth) acrylate (B).

  The active energy ray-curable resin composition of the present invention can be suitably used for an active energy ray-curable coating material because a coating film excellent in scratch resistance, substrate adhesion, hot water resistance and appearance can be obtained.

  The active energy ray-curable coating material described above contains the active energy ray-curable resin composition of the present invention, but as other formulations, an antistatic agent, an antifoaming agent, a viscosity modifier, and a light-resistant stabilizer. Additives such as a weather stabilizer, a heat stabilizer, an ultraviolet absorber, an antioxidant, a leveling agent, and a pigment dispersant can be used.

  Moreover, the active energy ray-curable coating material of the present invention can be formed into a cured coating film by irradiating active energy rays after being applied to a substrate. The active energy rays refer to ionizing radiation such as ultraviolet rays, electron beams, α rays, β rays, and γ rays. When irradiating ultraviolet rays as active energy rays to form a cured coating film, it is preferable to improve the curability by adding a photopolymerization initiator (D) to the active energy ray-curable coating material of the present invention. Further, if necessary, a photosensitizer can be further added to improve curability. On the other hand, when ionizing radiation such as electron beam, α-ray, β-ray, and γ-ray is used, it cures quickly without using a photopolymerization initiator or photosensitizer. It is not necessary to add D) or a photosensitizer.

  Examples of the photopolymerization initiator (D) include intramolecular cleavage type photopolymerization initiators and hydrogen abstraction type photopolymerization initiators. Examples of the intramolecular cleavage type photopolymerization initiator include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy. 2-methylpropan-1-one, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenylketone, 2-methyl-2-morpholino (4-thiomethyl) Acetophenone compounds such as phenyl) propan-1-one and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone; benzoins such as benzoin, benzoin methyl ether and benzoin isopropyl ether; 6-Trimethylbenzoindiphenylphosphie Oxide, bis (2,4,6-trimethylbenzoyl) - acyl phosphine oxide-based compounds such as triphenylphosphine oxide; benzyl, and methyl phenylglyoxylate ester.

  On the other hand, examples of the hydrogen abstraction type photopolymerization initiator include benzophenone, methyl 4-phenylbenzophenone, o-benzoylbenzoate, 4,4′-dichlorobenzophenone, hydroxybenzophenone, 4-benzoyl-4′-methyl-diphenyl sulfide. Benzophenone compounds such as acrylated benzophenone, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, 3,3′-dimethyl-4-methoxybenzophenone; 2-isopropylthioxanthone, 2,4 -Thioxanthone compounds such as dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone; Aminobenzophenone compounds such as Michler's ketone and 4,4'-diethylaminobenzophenone; 2-chloro acridone, 2-ethyl anthraquinone, 9,10-phenanthrenequinone, camphorquinone, and the like. These photopolymerization initiators (D) can be used alone or in combination of two or more.

  Examples of the photosensitizer include amines such as aliphatic amines and aromatic amines, ureas such as o-tolylthiourea, sulfur such as sodium diethyldithiophosphate, s-benzylisothuronium-p-toluenesulfonate, and the like. Compound etc. are mentioned.

  The amount of these photopolymerization initiators and photosensitizers used is preferably 0.05 to 20 parts by mass, preferably 0.5 to 100 parts by mass with respect to 100 parts by mass of the non-volatile component in the active energy ray-curable paint of the present invention. 10 mass% is more preferable.

  The coating method of the active energy ray-curable coating of the present invention varies depending on the article to be coated, for example, a gravure coater, roll coater, comma coater, knife coater, air knife coater, curtain coater, kiss coater, shower coater, wheeler coater, Examples of the method include spin coater, dipping, screen printing, spraying, applicator, and bar coater.

  Furthermore, the active energy ray-curable coating material of the present invention is preferably diluted with an organic solvent in order to adjust the viscosity to be suitable for the above-described coating method. Examples of the organic solvent include aromatic hydrocarbon solvents such as toluene and xylene; methanol, ethanol, isopropanol, t-butanol, propylene glycol monomethyl ether, propylene glycol normal propyl ether, ethylene glycol monobutyl ether, diacetone alcohol, and the like. Alcohol solvents; ester solvents such as ethyl acetate, butyl acetate, isobutyl acetate, normal propyl acetate, and propylene glycol monomethyl ether acetate; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, and cyclohexanone. These solvents can be used alone or in combination of two or more.

  As described above, the active energy ray for curing the active energy ray-curable composition of the present invention is an ionizing radiation such as an ultraviolet ray, an electron beam, an α ray, a β ray, and a γ ray. Or as a curing device, for example, a germicidal lamp, an ultraviolet fluorescent lamp, a carbon arc, a xenon lamp, a high-pressure mercury lamp for copying, an intermediate or high-pressure mercury lamp, an ultra-high pressure mercury lamp, an electrodeless lamp, a metal halide lamp, natural light, etc. Examples of the electron beam include ultraviolet rays, a scanning type, and a curtain type electron beam accelerator.

  The active energy ray-curable coating material of the present invention can impart a cured coating film excellent in scratch resistance, substrate adhesion, hot water resistance and appearance to the surface of various articles.

  The active energy ray-curable coating material of the present invention may be applied directly to an article to be coated, or after applying a primer coating material suitable for the material to be coated, the active energy beam-curing property of the present invention. Paint may be applied.

  As materials of articles to be coated, polycarbonate (hereinafter abbreviated as “PC”), acrylonitrile-butadiene-styrene copolymer (hereinafter abbreviated as “ABS”), PC-ABS polymer alloy. , Various resins such as polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polyamide (PA), polypropylene (PP); fiber reinforced plastic (FRP) in which filler such as glass fiber is added to these resins; iron, copper , Various metals such as zinc, aluminum and magnesium, and alloys thereof.

  Moreover, said active energy ray hardening coating material can be used as a coating material which coats various articles | goods. Articles that can be coated with the active energy ray-curable paint of the present invention include housings for home appliances such as TVs, refrigerators, washing machines, and air conditioners; electronic devices such as personal computers, smartphones, mobile phones, digital cameras, and game machines. Equipment casings; interior materials for various vehicles such as automobiles and railway vehicles; FRP bathtubs and the like.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. The hydroxyl value of the acrylic resin was measured in accordance with JIS test method K 0070-1992, the weight average molecular weight (Mw) was measured under the following GPC measurement conditions, and the solubility parameter ( SP) is determined by the following turbidity titration method.

[GPC measurement conditions]
Measuring device: High-speed GPC device (“HLC-8220GPC” manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series.
"TSKgel G5000" (7.8 mm ID x 30 cm) x 1 "TSKgel G4000" (7.8 mm ID x 30 cm) x 1 "TSKgel G3000" (7.8 mm ID x 30 cm) x 1 “TSKgel G2000” (7.8 mm ID × 30 cm) × 1 detector: RI (differential refractometer)
Column temperature: 40 ° C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL / min Injection amount: 100 μL (tetrahydrofuran solution with a sample concentration of 4 mg / mL)
Standard sample: A calibration curve was prepared using the following monodisperse polystyrene.

(Monodispersed polystyrene)
"TSKgel standard polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-2500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-5000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-550" manufactured by Tosoh Corporation

"Calculation formula of SP by turbidity titration method"
VmL ^1/2 (δ−δmL) ≈VmH ^1/2 (δmH−δ)
δ = (VmL ^1/2 δmL + VmH ^1/2 δmH) / (VmL ^1/2 + VmH ^1/2 )
δ: SP of acrylic resin (cal / ml) ^1/2 )
VmL: low polar solvent molecular volume with low SP (ml / mol)
VmH: Molecular volume of high polar solvent with high SP (ml / mol)
δmL: SP of low polarity solvent with low SP ((cal / ml) ^1/2 )
δmH: SP of high polarity solvent with high SP ((cal / ml) ^1/2 )
"Titration method"
0.500 g of acrylic resin was weighed into a 50 ml Erlenmeyer flask. To this, 10 ml of tetrahydrofuran as a dissolving solvent was added to completely dissolve the acrylic resin, and then normal hexane (low polarity solvent) was dropped while keeping the temperature at 25 ° C., and the turbidity drop (ml) was measured. In the same procedure, turbidity drip quantification (ml) in ion-exchanged water (high polarity solvent) was measured. The 50 ml Erlenmeyer flask being titrated was placed on a printed material (10-point type) while being kept at 25 ° C., and when looking into the 50 ml Erlenmeyer flask from above, the printed material (through the liquid layer was prepared under the Erlenmeyer flask ( The end point was defined as the point when the 10-point type) was cloudy and blurred. In addition, 25 degreeC SP of tetrahydrofuran, normal hexane, and ion-exchange water used the following values.
Molecular volume of tetrahydrofuran: 81 (ml / mol)
Molecular volume of normal hexane (VmL): 132 (ml / mol)
Molecular volume of ion-exchanged water (VmH): 18 (ml / mol)
Tetrahydrofuran SP: 9.52 ((cal / ml) ^1/2 )
Normal hexane SP (δ mL): 7.24 ((cal / ml) ^1/2 )
SP (δmH) of ion-exchanged water: 23.50 ((cal / ml) ^1/2 )

(Synthesis Example 1: Synthesis of acrylic resin (A-1))
A reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, a cooling tube and a nitrogen gas introduction tube was charged with 1000 parts by mass of methyl isobutyl ketone (hereinafter abbreviated as “MIBK”), and the temperature was 115 ° C. under a nitrogen gas stream. The temperature was raised to. Next, at the same temperature, 518 parts by mass of methyl methacrylate, 232 parts by mass of 2-hydroxyethyl methacrylate, 250 parts by mass of synthetic lauryl methacrylate (a mixture of “Acryester SL”, lauryl methacrylate and tridecyl methacrylate, manufactured by Mitsubishi Rayon Co., Ltd.) and tert -A mixture of 23 parts by mass of butylperoxy-2-ethylhexanoate was added dropwise over 4 hours. Even after completion of dropping, the reaction was continued for 19 hours at the same temperature to obtain a 50% by mass solution of acrylic resin (A-1). The solubility parameter of this acrylic resin (A-1) was 10.74, and the hydroxyl value was 100 mgKOH / g.

(Synthesis Examples 2 to 8: Synthesis of acrylic resins (A-2) to (A-7))
A 50% by mass solution of acrylic resins (A-2) to (A-7) was obtained in the same manner except that the acrylic monomer used in Synthesis Example 1 was changed to the charge shown in Table 1. .

  Table 1 shows the charged amounts and properties of monomers as raw materials for the acrylic resins (A-1) to (A-7) synthesized above.

  The synthetic lauryl methacrylate in Table 1 is acrylate ester SL (Mitsubishi Rayon Co., Ltd., mixture of lauryl methacrylate and tridecyl methacrylate).

(Synthesis Example 8: Synthesis of urethane acrylate composition (B-1))
In a reaction vessel equipped with a stirrer, thermometer, dropping funnel, condenser and air inlet, 150.8 parts by mass of n-butyl acetate, 111 parts by mass of isophorone diisocyanate, 1.2 parts by mass of di-t-butylhydroxytoluene, Methoquinone 0.12 parts by mass and dioctyl tin versatate 0.12 parts by mass were charged, and the temperature was raised to 50 ° C. while stirring under aeration of air. Next, a mixture of pentaerythritol triacrylate (hereinafter abbreviated as “PETA”) and pentaerythritol tetraacrylate (“Aronix M305” manufactured by Toagosei Co., Ltd., pentaerythritol triacrylate / pentaerythritol tetraacrylate = 60/40 (mass) Ratio), hydroxyl value: 115; hereinafter abbreviated as “PETA mixture.”) Urethane reaction is carried out by adding 491 parts by mass and stirring at 80 ° C. for 5 hours to obtain urethane acrylate (B-1) and pentaerythritol. An 80% by mass solution of a mixture with urethane (urethane acrylate (B-1) / pentaerythritol tetraacrylate = 67.5 / 32.5 (mass ratio)) was obtained (acryloyl group of urethane acrylate (B-1)). Concentration: 7 .3 mmol / g).

(Example 1: Preparation of active energy ray-curable resin composition (1))
The urethane acrylate (B-1) obtained in Synthesis Example 8 was added to 12 parts by mass (6 parts by mass as the acrylic resin (A-1)) of a 50% by mass solution of the acrylic resin (A-1) obtained in Synthesis Example 1. ) And pentaerythritol tetraacrylate 80% by weight solution 22.2 parts by mass (12 parts by mass as urethane (meth) acrylate (B-1), 5.76 parts by mass as pentaerythritol tetraacrylate) and initiation of photopolymerization 0.8 parts by mass of an agent (“Irgacure 184” manufactured by BASF Japan Ltd., 1-hydroxycyclohexyl phenyl ketone) was added and mixed uniformly with a disper to obtain an active energy ray-curable composition (1).

(Examples 2 to 7: Preparation of active energy ray-curable compositions (2) to (7))
By operating in the same manner as in Example 1 except that the acrylic resin (A-1), urethane acrylate (B-1) and pentaerythritol tetraacrylate used in Example 1 were changed to the compositions shown in Table 2 below. Active energy ray-curable compositions (2) to (7) were prepared.

(Comparative Examples 1-2: Preparation of active energy ray-curable compositions (R1) to (R2))
By operating in the same manner as in Example 1 except that the acrylic resin (A-1), urethane acrylate (B-1) and pentaerythritol tetraacrylate used in Example 1 were changed to the compositions shown in Table 2 below. Active energy ray-curable compositions (R1) to (R2) were prepared.

  Table 2 shows the compositions of the active energy ray-curable compositions (1) to (7) and (R1) to (R2) obtained above.

(Example 8: Evaluation of active energy ray-curable composition (1))
Thinner (diacetone alcohol / isobutyl acetate / ethyl acetate / acetic acid) until the viscosity of the active energy ray-curable composition (1) obtained above is sprayable on the surface of a PC resin plate (thickness 2 mm). After being diluted with butyl = 30/30/20/20 (mass%), spray coating was performed so that the film thickness after drying was 15 μm. Then, after leaving at room temperature (25 ° C.) for 5 minutes, after preliminary drying in a dryer at 60 ° C. for 5 minutes, using a high-pressure mercury lamp with an output of 80 W / cm, an irradiation amount of 0.8 J / cm ² Ultraviolet irradiation was performed to produce a cured coating film for evaluation.

[Evaluation of coating appearance]
The haze value of the cured coating film for evaluation obtained above was measured using a haze meter (“NDH 5000”, manufactured by Nippon Denshoku Industries Co., Ltd.). From the obtained value, the coating film appearance was determined according to the following criteria. evaluated.
◎: Less than 1 ○: 1 or more and less than 3 Δ: 3 or more and less than 10 ×: 10 or more

[Evaluation of scratch resistance]
The cured coating film for evaluation obtained above is set on RUBBING TESTER (manufactured by Ohira Riken Chemical Co., Ltd.), and the surface of the coating film using steel wool (manufactured by Nippon Steel Wool Co., Ltd., BON STAR (No. 000)). Was rubbed 100 times with a load of 500 g. From the difference in the haze values (Δhaze) of the cured coating film before and after rubbing, the scratch resistance of the coating film was evaluated according to the following criteria.
◎: Less than 5 ○: 5 or more and less than 10 Δ: 10 or more to less than 15 ×: 15 or more

[Evaluation of substrate adhesion]
The cured coating film for evaluation obtained above was measured based on the cross cut test method of JIS K-5400. A 1 mm wide cut is made on the cured coating film with a cutter, the number of grids is 100, cellophane tape is applied so as to cover all grids, and they are peeled off quickly to adhere and remain. From the number, the adhesion was evaluated according to the following criteria.
◎: 95 or more and less than 100 ○: 80 or more and less than 95 △: 50 or more and less than 79 ×: Less than 49

[Evaluation of hot water resistance (adhesion evaluation after hot water test)]
After the cured coating film for evaluation obtained above was immersed in boiling water at 100 ° C. for 3 hours, the removed coating film was immediately operated in the same manner as in the evaluation of substrate adhesion, and heat-resistant according to the following criteria. The aqueous property (adhesion after the hot water test) was evaluated.
◎: 95 or more and less than 100 ○: 80 or more and less than 95 △: 50 or more and less than 79 ×: Less than 49

(Examples 9 to 14: Evaluation of active energy ray-curable compositions (2) to (7))
Instead of the active energy ray-curable composition (1) obtained in Example 1 used in Example 8, the active energy ray-curable compositions (2) to (7) obtained in Examples 2 to 7 were used. A cured coating film for evaluation was produced in the same manner as in Example 8 except that each was used, and the appearance, scratch resistance, substrate adhesion and hot water resistance were evaluated.

(Comparative Examples 3 to 4: Evaluation of active energy ray-curable compositions (R1) to (R2))
Instead of the active energy ray-curable composition (1) obtained in Example 1 used in Example 9, the active energy ray-curable compositions (R1) to (R2) obtained in Comparative Examples 1 and 2 were used. A cured coating film for evaluation was produced in the same manner as in Example 8 except that each was used, and the appearance, scratch resistance, substrate adhesion and hot water resistance were evaluated.

  Table 3 shows the evaluation results of Examples 8 to 14 and Comparative Examples 3 to 4.

  From the evaluation results of Examples 8 to 14, it was found that the active energy ray-curable composition of the present invention can form a coating film excellent in appearance, scratch resistance, substrate adhesion, and hot water resistance. .

  On the other hand, Comparative Example 3 is an example in which an acrylic monomer having a hydroxyl group is not used as a raw material for the acrylic resin that is a component of the active energy ray-curable composition of the present invention. It was found that the scratch resistance was poor.

  Comparative Example 4 is an example in which an acrylic monomer having an alkyl group having 12 to 18 carbon atoms is not used as a raw material for an acrylic resin that is a component of the active energy ray-curable composition of the present invention. It was found that the hot water resistance of the resulting coating film was poor.

Claims (6)

  An acrylic monomer having a hydroxyl group (a1), an acrylic monomer having an alkyl group having 12 to 18 carbon atoms (a2), and an acrylic monomer having an alkyl group having 1 to 4 carbon atoms (a3 ) Is an active energy ray-curable resin composition containing an acrylic resin (A) obtained by copolymerization using essential raw materials and a urethane (meth) acrylate (B), the acrylic resin (A) An active energy ray-curable resin composition having a solubility parameter of 9.4 to 11.5.   The said acrylic monomer (a1) in the monomer component which is a raw material of the said acrylic resin (A) is 5-40 mass%, The said acrylic monomer (a2) is 5-60 mass%. The active energy ray-curable resin composition according to claim 1, wherein the acrylic monomer (a3) is in the range of 5 to 90% by mass.   The active energy ray-curable resin composition according to claim 1 or 2, wherein the urethane (meth) acrylate (B) has a (meth) acryloyl group concentration of 4 to 11 mmol / g. The mass ratio [(A) / (B)] of the acrylic resin (A) and the urethane (meth) acrylate composition (B) is in the range of 10/90 to 70/30 . The active energy ray-curable resin composition according to any one of the above.
  An active energy ray-curable coating composition comprising the active energy ray-curable resin composition according to any one of claims 1 to 4.   An article coated with the active energy ray-curable paint according to claim 5.