Active energy ray curable composition for exterior building materials and use thereof

Abstract

To provide an active energy ray-curable composition for exterior building material that can form a coating film having excellent long-term weather resistance in which there is little loss of gloss or discoloration even when exposed to light or water for a long period of time and there occurs no cracks.SOLUTION: Provided is an active energy ray-curable composition for exterior building material, which is an active energy ray-curable composition for exterior building material containing an urethane (meth)acrylate (A) obtained by using an isophorone diisocyanate (a1) and a (meth)acrylate monomer (a2) having a hydroxyl group and a photopolymerizable unsaturated group, and having no isocyanurate skeleton, a (meth)acrylate monomer (B), and a photopolymerization initiator (C), and when the (meth)acrylate monomer (B) contains a polyoxyalkylene-modified (meth)acrylate (b1), the contained amount of the (meth)acrylate (b1) is 15 mass% or less for 100 mass% of non-volatile component of the composition.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an active energy ray-curable composition for exterior building materials, a coating film, a substrate with a coating film, and a method for producing the same. [Background technology]

[0002] Traditionally, solvent-based paints and water-based paints have been used for exterior building materials such as siding boards. However, solvent-based paints contain a large amount of volatile organic compounds (VOCs), so their use is restricted from the standpoint of environmental conservation and the safety of the working environment, and water-based paints have difficulty forming thick coatings (e.g., 50 μm) using paint machines such as roll coaters, and it has also been difficult to form coatings with high gloss (high appearance).

[0003] As described above, since solvent-based paints and water-based paints each have their own problems, the use of active energy ray-curable paints has been considered as an alternative because they can be made to be non-solvent-based, containing virtually no solvent, and can form coating films with excellent aesthetics (high gloss).

[0004] The paint applied to exterior building materials such as siding boards is required to be capable of forming a coating film having excellent weather resistance. As an active energy ray-curable coating material having such excellent weather resistance, Patent Document 1 describes a coating material containing a urethane acrylate resin composed of an isocyanurate and a compound having a hydroxyl group and a (meth)acryloyl group, and a radical polymerizable monomer having an oxygen- and / or nitrogen-containing heterocycle. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2002-53774 A Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, coating films formed on exterior building materials are expected to have weather resistance for longer periods (e.g., 10 years or more). Specifically, they are expected to have excellent long-term weather resistance, with little loss of gloss or discoloration even when exposed to light (ultraviolet rays) or water for long periods of time, and no cracks (excellent crack resistance). However, it was found that coating films formed from conventional active energy ray-curable coating materials as described in Patent Document 1 suffer from loss of gloss and cracks when exposed to light or water for a long period of time, and there is room for improvement in these respects.

[0007] The present invention has been made in view of the above, and an object of the present invention is to provide an active energy ray-curable composition for exterior building materials that is capable of forming a coating film that is excellent in long-term weather resistance, with little loss in gloss or discoloration, and no cracks even when exposed to light or water for a long period of time. [Means for solving the problem]

[0008] As a result of intensive research into methods for solving the above problems, the inventors discovered that the above problems can be solved by a specific composition, and thus completed the present invention. A configuration example of the present invention is as follows.

[0009] [1] A urethane (meth)acrylate (A) having no isocyanurate skeleton, which is obtained using isophorone diisocyanate (a1) and a (meth)acrylate monomer (a2) having a hydroxyl group and a photopolymerizable unsaturated group; (Meth)acrylate monomer (B), and Photopolymerization initiator (C) An active energy ray-curable composition for exterior building materials comprising: When the (meth)acrylate monomer (B) contains a polyoxyalkylene-modified (meth)acrylate (b1), the content of the (meth)acrylate (b1) is 15 mass% or less based on 100 mass% of the nonvolatile content of the composition. An active energy ray-curable composition for exterior building materials.

[0010] [2] The urethane (Meta) The composition according to [1], wherein the acrylate (A) and the (meth)acrylate monomer (B) do not have a polyoxyalkylene structure.

[0011] [3] The composition according to [1] or [2], wherein the (meth)acrylate monomer (B) contains a monofunctional monomer.

[0012] [4] The composition according to any one of [1] to [3], which is for use in a paint.

[0013] [5] A coating film formed from the composition according to any one of [1] to [4]. [6] A substrate with a coating film comprising a substrate and the coating film according to [5].

[0014] [7] A method for producing a substrate with a coating film, comprising the steps of applying the composition according to any one of [1] to [4] to at least a part of a substrate, and then irradiating the substrate with active energy rays. Effect of the Invention

[0015] According to the present invention, there is provided an active energy ray-curable composition for exterior building materials that is capable of forming a coating film that is excellent in long-term weather resistance, with little loss in gloss or discoloration, and no cracks even when exposed to light or water for a long period of time. Furthermore, according to the present invention, a coating film with high gloss can be formed without cracking even when it is made thick. In particular, according to the present invention, it is possible to form a coating film which has excellent water resistance (excellent adhesion to the substrate) even when in contact with warm water for a long period of time (e.g., 240 hours), and which does not crack even when exposed to ultraviolet rays equivalent to about 15 years of exposure to ultraviolet rays (the accelerated weather resistance test using an Eye Super UV Tester (manufactured by Iwasaki Electric Co., Ltd.) lasts for 1,500 hours), and which shows little loss of gloss or discoloration. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] <<Active energy ray-curable composition for exterior building materials>> The active energy ray-curable composition for exterior building materials according to the present invention (hereinafter also referred to as "the composition") is A urethane (meth)acrylate (A) (hereinafter also referred to as "component (A)"; the same applies to other components) obtained by using isophorone diisocyanate (a1) and a (meth)acrylate monomer (a2) having a hydroxyl group and a photopolymerizable unsaturated group and having no isocyanurate skeleton, (Meth)acrylate monomer (B), and Photopolymerization initiator (C) Contains When the (meth)acrylate monomer (B) contains a polyoxyalkylene-modified (meth)acrylate (b1), the content of the (meth)acrylate (b1) is 15 mass % or less based on 100 mass % of the nonvolatile content of the composition.

[0017] In this specification, "(meth)acrylate" refers to acrylate and / or methacrylate, and similar descriptions apply thereto.

[0018] Since the present composition can form a highly glossy coating film with excellent weather resistance, it is preferable that the composition is used to form the coating film of the outermost layer (uppermost layer) when forming a coating film on a substrate so that these effects can be more fully exhibited. When forming a coating film as the outermost layer, the coating film may be formed directly on the substrate, but is usually formed on the substrate via at least one layer selected from a sealer layer, an undercoat layer, an intermediate coat layer, and a decorative layer (e.g., a colored layer), etc.

[0019] Since the present composition has excellent coating workability, it is preferably a composition for use in paints, that is, a paint composition.

[0020] <Urethane (meth)acrylate (A)> The component (A) is a urethane (meth)acrylate having no isocyanurate skeleton, which is obtained using isophorone diisocyanate (a1) and a (meth)acrylate monomer (a2) having a hydroxyl group and a photopolymerizable unsaturated group. By using such component (A) together with other components, a coating film having the above-mentioned effects can be formed. In particular, since isophorone diisocyanate (a1), which is an alicyclic isocyanate, is used as the isocyanate, a coating film having high gloss and excellent weather resistance, which does not deteriorate much in gloss and does not crack even when exposed to ultraviolet rays for a long period of time, can be formed. In addition, isophorone diisocyanate does not have an isocyanurate skeleton, but rather has an alicyclic skeleton to which an isocyanate group and an isocyanate-containing group (-CH-NCO) having a different chemical structure are bonded. The urethane (meth)acrylate obtained using such a compound can form a coating film that has high gloss and excellent long-term weather resistance with little loss in gloss and no cracks, even when a thick coating film is formed on an exterior building material whose substrate may shrink. The component (A) may be used alone or in combination of two or more.

[0021] It is preferable that component (A) does not have a polyoxyalkylene structure from the viewpoint of long-term weather resistance, particularly the ease of forming a coating film with little loss in gloss even when exposed to ultraviolet rays for a long period of time. When synthesizing the component (A), for example, the monomer (a2) or the polyol (a3) ​​below may have a polyoxyalkylene structure, specifically, -(AO) n -[A is independently an alkenyl group having 2 to 6 carbon atoms. n is a number exceeding 1, and preferably n is 2 to 30.] can be obtained by not using a compound having a structure represented by the following formula:

[0022] The photopolymerizable unsaturated group refers to an unsaturated group that undergoes a polymerization reaction when exposed to light, such as visible light or active energy rays. Specific examples of such photopolymerizable unsaturated groups include a (meth)acryloyl group, a (meth)acryloyloxy group, a vinyl group, and an allyl group.

[0023] Component (A) is preferably an oligomer or polymer, more preferably an oligomer.

[0024] The raw material monomers of component (A) are not particularly limited as long as they include isophorone diisocyanate (a1) and a (meth)acrylate monomer (a2) having a hydroxyl group and a photopolymerizable unsaturated group, and may further include a polyol (a3), and preferably includes a polyol (a3). Component (A) can be synthesized by copolymerizing the raw material monomers, and a commercially available product may be used. When copolymerizing the raw material monomers, known additives such as polymerization inhibitors and catalysts may be used.

[0025] The monomer (a2) may be, for example, a monofunctional (meth)acrylate having one hydroxyl group. Such a monomer (a2) preferably has a hydrocarbon moiety having 2 to 20 carbon atoms, or a moiety in which the hydrocarbon moiety is partially replaced with a halogen atom or an oxygen atom. Here, the hydrocarbon moiety refers to an organic group having at least one selected from a linear or branched aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group, and the aliphatic hydrocarbon group and the alicyclic hydrocarbon group may be saturated or unsaturated. It is preferable not to use a polyoxyalkylene-modified (meth)acrylate (b1) as the monomer (a2). The monomer (a2) may be used alone or in combination of two or more.

[0026] Specific examples of the monomer (a2) include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, hydroxyhexyl (meth)acrylate, 2-hydroxy-3-chloropropyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, etc. In addition to these, modified products such as (poly)caprolactone-modified 2-hydroxyethyl (meth)acrylate may also be used. Of these, 2-hydroxypropyl acrylate is preferred.

[0027] As the polyol (a3), for example, known polyols such as polyester polyols and polyolefin polyols can be used. Specific examples thereof include polycaprolactone diol, alkylene polyol, neopentyl glycol, 1,6-hexanediol, and trimethylolpropane. The polyol (a3) ​​may be used alone or in combination of two or more.

[0028] The amount of the monomer (a2) used in the synthesis of the component (A) is usually 10 to 300 parts by mass, and preferably 50 to 150 parts by mass, per 100 parts by mass of the isophorone diisocyanate (a1). When the polyol (a3) ​​is used, the amount of the polyol (a3) ​​used is usually 10 to 300 parts by mass, and preferably 30 to 120 parts by mass, per 100 parts by mass of the isophorone diisocyanate (a1).

[0029] From the viewpoint that the present composition having excellent coating workability can be easily obtained without using a solvent, component (A) has a weight average molecular weight in terms of polystyrene, as measured by gel permeation chromatography (GPC), of usually 500 to 20,000, preferably 600 to 8,000, and more preferably 650 to 4,000.

[0030] Because the present composition has excellent coating workability and can be easily obtained without using a solvent, the viscosity of component (A) at 25°C measured using a B-type viscometer is preferably 500 to 50,000 mPa s, more preferably 1,500 to 25,000 mPa s, and particularly preferably 3,000 to 15,000 mPa s.

[0031] The content of component (A) in the present composition is preferably 20 to 80 mass %, more preferably 40 to 70 mass %, relative to 100 mass % of the nonvolatile content of the present composition, from the viewpoints of long-term weather resistance, particularly of being able to easily form a coating film with little loss in gloss even when exposed to ultraviolet rays for a long period of time. In the present invention, the non-volatile content refers to components other than the solvent. The non-volatile content of the present composition also refers to components that constitute a coating film when the present composition is cured.

[0032] <(Meth)acrylate Monomer (B)> The component (B) is a compound other than the component (A). When the component (B) contains a polyoxyalkylene-modified (meth)acrylate (b1), the content of the (meth)acrylate (b1) is 15 mass% or less based on 100 mass% of the nonvolatile content of the composition. In other words, component (B) is (I) A case in which no polyoxyalkylene-modified (meth)acrylate (b1) is contained, (II) In the case where polyoxyalkylene-modified (meth)acrylate (b1) is contained In the case of the (II) embodiment, the content of the polyoxyalkylene-modified (meth)acrylate (b1) is limited to 15% by mass or less based on 100% by mass of the nonvolatile content of the composition, and is preferably 14.5% by mass or less, more preferably 7% by mass or less, from the viewpoints of long-term weather resistance, particularly of being able to easily form a coating film with little loss of gloss even when exposed to ultraviolet rays for a long period of time, and the like. The component (B) may be used alone or in combination of two or more.

[0033] Component (B) is a polyoxyalkylene structure, specifically, -(AO) from the viewpoint of long-term weather resistance, particularly the ease of forming a coating film with little loss of gloss even when exposed to ultraviolet rays for a long period of time. n -[A is independently an alkenyl group having 2 to 6 carbon atoms. n is a number exceeding 1, and preferably n is 2 to 30.] is not preferably contained. In the case of (I) above, such a component (B) means that it does not contain a monomer having a polyoxyalkylene structure.

[0034] It is preferable that component (B) contains a monofunctional (meth)acrylate compound, since this can reduce the viscosity of the composition, improve coating workability, and facilitate the formation of a coating film that has excellent adhesion to the substrate, particularly the decorative layer. In addition, from the viewpoint of being able to easily form a coating film having excellent hardness and scratch resistance, it is preferable to use a difunctional or higher functional (meth)acrylate compound, and it is more preferable to use a difunctional (meth)acrylate compound in combination with a trifunctional or higher functional (meth)acrylate compound. In view of the fact that these effects can be exerted simultaneously, it is particularly preferable to use, as component (B), a monofunctional (meth)acrylate compound, a difunctional (meth)acrylate compound, and a trifunctional or higher (meth)acrylate compound in combination.

[0035] ·Monofunctional (meth)acrylate compounds Examples of the monofunctional (meth)acrylate compound include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, and tridecyl (meth)acrylate. acrylate, isomyristyl (meth)acrylate, alkyl (meth)acrylate (C12-C13, including a mixture of those with 12 carbon atoms and those with 13 carbon atoms), cetyl (meth)acrylate, cyclohexyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, benzyl (meth)acrylate, isobornyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate , 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxyethyl phthalic acid, 2-(meth)acryloyloxypropyl hydrogen phthalate, 2-(meth)acryloyloxypropyl hexahydrohydrogen terephthalate, 2-(meth)acryloyloxypropyl tetrahydrohydrogen terephthalate, 2-(meth)acryloyloxyethyl hexahydrophthalic acid, 2-(meth)acryloyl Oxyethyl-2-hydroxyethyl-phthalic acid, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, 2-(meth)acryloyloxyethyl acid phosphate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylamide, trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, perfluorooctylethyl (meth)acrylate,Examples of the ω-carboxy-polycaprolactone (n≒2) mono(meth)acrylate, (meth)acrylic acid dimer (n≒1.4), N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-2-hydroxyethyl(meth)acrylamide, caprolactone(meth)acrylate, neopentyl glycol(meth)acrylic acid benzoate, tribromophenyl(meth)acrylate, isononyl(meth)acrylate, isostearyl(meth)acrylate, and t-butylcyclohexyl(meth)acrylate. Of these, 2-ethylhexyl (meth)acrylate and cyclohexyl (meth)acrylate are preferred. When a monofunctional (meth)acrylate compound is used, the monofunctional (meth)acrylate compound used may be one type or two or more types.

[0036] Bifunctional (meth)acrylate compounds Examples of bifunctional (meth)acrylate compounds include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl (meth)acrylate, zinc di(meth)acrylate, and trimethylolpropane di(meth)acrylic acid benzoate. Among these, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, and 1,4-butanediol di(meth)acrylate are preferred. When a bifunctional (meth)acrylate compound is used, the bifunctional (meth)acrylate compound used may be one type or two or more types.

[0037] Trifunctional or higher (meth)acrylate compounds Examples of trifunctional or higher (meth)acrylate compounds include trimethylolpropane tri(meth)acrylate, glycerin tri(meth)acrylate, tris(meth)acryloyloxyethyl phosphate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. Among these, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and trimethylolpropane tri(meth)acrylate are preferred. When a tri- or higher functional (meth)acrylate compound is used, the tri- or higher functional (meth)acrylate compound used may be one type or two or more types.

[0038] Specific examples of the polyoxyalkylene-modified (meth)acrylate (b1) include alkylene oxide-modified, specifically ethylene oxide-modified, propylene oxide-modified, and / or butylene oxide-modified, glycerin tri(meth)acrylate, diglycerin tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, trimethylolpropane tri(meth)acrylate, dimethylolpropane tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0039] The content of component (B) in the present composition is preferably 5 to 70 mass %, more preferably 20 to 50 mass %, relative to 100 mass % of the nonvolatile content of the present composition, from the viewpoints of long-term weather resistance, particularly of being able to easily form a coating film with little loss in gloss even when exposed to ultraviolet rays for a long period of time.

[0040] When the present composition contains a monofunctional (meth)acrylate compound, the content thereof is preferably 5 to 65 mass %, more preferably 10 to 45 mass %, relative to 100 mass % of the nonvolatile content of the present composition, from the viewpoint of being able to easily form a coating film that has excellent adhesion to the substrate, particularly a decorative layer. When the present composition contains a bifunctional (meth)acrylate compound, the content thereof is preferably 1 to 65 mass %, more preferably 5 to 45 mass %, relative to 100 mass % of the nonvolatile content of the present composition, from the viewpoint of being able to easily form a coating film having a good balance between crack resistance and hardness. When the present composition contains a trifunctional or higher functional (meth)acrylate compound, the content thereof is preferably 0.1 to 50 mass %, more preferably 1 to 30 mass %, relative to 100 mass % of the nonvolatile content of the present composition, from the viewpoint of easily forming a coating film having a good balance between crack resistance and hardness.

[0041] <Photopolymerization initiator (C)> The component (C) is not particularly limited, and any conventionally known photopolymerization initiator can be used. The component (C) may be used alone or in combination of two or more.

[0042] Specific examples of component (C) include: Benzoin-based photopolymerization initiators such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; Acetophenone-based photopolymerization initiators such as benzyl dimethyl ketal (also known as 2,2-dimethoxy-2-phenylacetophenone), diethoxyacetophenone, 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 4-t-butyl-trichloroacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)-phenyl(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexylphenyl ketone, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one; Benzophenone-based photopolymerization initiators such as benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, and 3,3'-dimethyl-4-methoxybenzophenone; Thioxanthone-based photopolymerization initiators such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, and 2,4-diisopropylthioxanthone; Acylphosphine oxide photoinitiators such as diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide; etc.

[0043] The content of component (C) is preferably 0.1 to 30 mass %, more preferably 1 to 20 mass %, relative to 100 mass % of the nonvolatile content of the composition, from the viewpoint of being able to easily form a coating film that has excellent adhesion to the substrate and long-term weather resistance.

[0044] <Other ingredients> In addition to the above-mentioned components (A) to (C), other components such as extender pigments, coloring pigments, anti-settling agents, dispersants, defoamers, leveling agents, polymerization inhibitors, ultraviolet absorbers, light stabilizers, and organic solvents can be used in the composition as necessary, provided the effects of the present invention are not impaired. These other components may each be used alone or in combination of two or more.

[0045] [Extender pigments, color pigments] Examples of the extender pigment include talc, nepheline syenite, calcium carbonate, clay, silica, and mica, and examples of the color pigment include titanium oxide, carbon black, and iron oxide (red oxide). It is preferable that these extender pigments and coloring pigments are capable of imparting aesthetic appearance and base hiding power to the coating film to be formed.

[0046] When an extender pigment and a color pigment are used, the content thereof is preferably from 1 to 30% by mass, and more preferably from 5 to 15% by mass, relative to 100% by mass of the nonvolatile content of the present composition.

[0047] [Antifoaming agent] The present composition preferably contains an antifoaming agent, since this can inhibit the generation of bubbles and improve the appearance of the resulting coating film. As the defoaming agent, various conventionally known defoaming agents such as polymer-based, acrylic-based, silicone-based, mineral oil-based, and olefin-based defoaming agents can be used, with polymer-based and olefin-based defoaming agents being preferred.

[0048] Examples of such defoamers include "BYK-1788", "BYK-1790", and "BYK-1794" manufactured by BYK Japan Co., Ltd.; "AFCONA-2290" manufactured by AFCANA ADDITIVE; "SpectraSyn 40", "SpectraSyn Elite150", and "SpectraSyn Elite65" manufactured by ExxonMobil Chemical Company; and "Efka PB 2720" manufactured by BASF.

[0049] When an antifoaming agent is used, the content thereof is preferably 0.0001 to 1 mass %, more preferably 0.01 to 0.5 mass %, relative to 100 mass % of the nonvolatile content of the present composition.

[0050] [Leveling agent] It is preferable to incorporate a leveling agent into the present composition, in order to improve the repelling of the coating film when the composition is applied, improve the wettability to the surface of the substrate, and easily form a coating film with a uniform thickness, etc. The leveling agent is not particularly limited, and examples thereof include various leveling agents such as fluorine-based, acrylic, and silicone-based leveling agents. When a leveling agent is used, its content is preferably 0.005 to 1.5 mass %, and more preferably 0.01 to 1 mass %, relative to 100 mass % of the nonvolatile content of the present composition.

[0051] [Polymerization inhibitor] Examples of the polymerization inhibitor include hydroquinone, hydroquinone monomethyl ether, benzoquinone, pt-butyl carbitol, and 2,6-di-t-butyl-4-methylphenol. When a polymerization inhibitor is used, the content thereof is preferably 0.005 to 1.5% by mass relative to 100% by mass of the nonvolatile content of the present composition.

[0052] [UV absorbers, light stabilizers] Examples of the ultraviolet absorber include a compound having a triazine skeleton, a compound having a benzotriazole skeleton, etc. Examples of the light stabilizer include a hindered amine-based light stabilizer.

[0053] Examples of the compound having a triazine skeleton include 2-(2-hydroxy-4-[isooctyloxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triazine, 2-[4-[(2-hydroxy-3-dodecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, and 2-[4-[(2-hydroxy-3-tridecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine. 2,4-bis(2-hydroxy-4-butyloxyphenyl)-6-(2,4-bis-butyloxyphenyl)-1,3,5-triazine, 2-[4-[(2-hydroxy-3-(2'-ethylhexyloxy)propyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine. Examples of commercially available products of these include "TINUVIN400", "TINUVIN405", "TINUVIN460", and "TINUVIN479" (all trade names, manufactured by BASF).

[0054] Examples of the compound having a benzotriazole skeleton include 2-[2-hydroxy-5-[2-(methacryloyloxy)ethyl]phenyl]-2H-benzotriazole, 2-(4-allyloxy-2-hydroxyphenyl)-2H-benzotriazole, and 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol. Examples of commercially available products include "RUVA-93" (manufactured by Otsuka Chemical Co., Ltd.), "DAINSORB T-31" (manufactured by Yamato Chemical Co., Ltd.), "DAINSORB T-84" (manufactured by Yamato Chemical Co., Ltd.), and "TINUVIN928" (manufactured by BASF).

[0055] Examples of the hindered amine-based light stabilizer include bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, methyl(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, 2,4-bis[N-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl)amino]-6-(2-hydroxyethylamine)-1,3,5-triazine, and decanedioic acid bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl)ester. Examples of commercially available products of these include "TINUVIN292", "TINUVIN144", and "TINUVIN123" (all trade names, manufactured by BASF).

[0056] When an ultraviolet absorber and a light stabilizer are used, the content thereof is preferably 0.1 to 2% by mass relative to 100% by mass of the nonvolatile content of the present composition.

[0057] [Organic solvents] The organic solvent is not particularly limited, but examples thereof include ethyl acetate, butyl acetate, xylene, and methoxypropyl acetate. The organic solvent may be incorporated into the composition as a mixture of the aforementioned components. Since the present composition has sufficient coating workability even without containing organic solvents, from the standpoint of environmental conservation and working environment safety, it is preferable that the composition does not contain organic solvents, particularly when the present composition is used for exterior building materials such as siding boards. However, if the composition contains organic solvents, it is preferable that the composition be a low-VOC composition with a low organic solvent content; specifically, the VOC content in the present composition is preferably 30 g / L or less, more preferably 10 g / L or less.

[0058] <Method of manufacturing the present composition> The present composition can be produced by mixing (kneading) the components (A) to (C) and, if necessary, the other components described above, using a mixer such as a high-speed disperser, a disperser, an agitator, or the like. In this mixing (kneading), each component may be added and mixed at once, or may be added and mixed in several batches. This mixing (kneading) may be performed while heating or cooling depending on the season, environment, etc.

[0059] <Coating film, substrate with coating film, and method for manufacturing substrate with coating film> The coating film according to the present invention (hereinafter also referred to as "the present coating film") is formed using the present composition, specifically, by irradiating the present composition with active energy rays, and the substrate with a coating film according to the present invention is a laminate having the present coating film and a substrate. Furthermore, the method for producing a substrate having a coating film according to the present invention comprises the steps of applying the composition to at least a portion of a substrate and then irradiating the substrate with active energy rays.

[0060] Examples of the substrate include inorganic substrates such as calcium silicate boards, slate boards, fiber cement boards, lightweight concrete boards, mortar boards, gypsum boards, stone, glass, tiles, roofing tiles, bricks, and ceramic siding materials; metal substrates such as metal siding materials, steel materials, stainless steel materials, and aluminum materials; organic substrates such as synthetic resin materials, wood materials, and paper; and composite substrates thereof. Among these, the present composition is preferably used for inorganic substrates, and more preferably used for inorganic decorative boards. These substrates may have a sealer layer, undercoat layer, intermediate coat layer, decorative layer, etc., formed thereon in advance.

[0061] The method for providing the present composition on at least a part of the substrate is not particularly limited, but a method in which the present composition is applied to the substrate or a method in which the substrate is immersed in the present composition is preferred. The method for applying the present composition to a substrate can be any conventional method, such as a method using a sponge roll coater, a natural roll coater, a reverse roll coater, a curtain flow coater, a knife coater, a die coater, an air spray, an airless spray, a roller, a brush, or the like.

[0062] Examples of the active energy rays include light rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, and infrared rays, as well as electromagnetic waves such as X-rays and gamma rays, electron beams, proton beams, and neutron beams. Among these, ultraviolet rays are preferred in terms of curing speed, availability of an irradiation device, price, and the like.

[0063] The method of curing the composition by irradiating it with active energy rays uses a high-pressure mercury lamp, metal halide lamp, xenon lamp, chemical lamp, or the like that emits light with a wavelength of about 75 to 2,600 nm, and the accumulated light amount is 30 to 3,000 mJ / cm. 2 and a method of irradiating light so as to achieve the above. During this curing, heating or the like may be carried out as necessary.

[0064] The thickness of the coating film is not particularly limited and may be appropriately selected depending on the desired application, but is preferably 5 to 100 μm, more preferably 10 to 60 μm, from the viewpoint of easily forming a coating film that does not crack even when exposed to light or water for a long period of time and has excellent long-term weather resistance. The coating film of the present invention has excellent crack resistance, particularly even when exposed to ultraviolet rays for a long period of time, even when it is a thick coating film, preferably 20 μm or more, more preferably 30 to 60 μm, and can therefore impart desired physical properties to a substrate for a long period of time. EXAMPLES

[0065] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

[0066] [Synthesis Example 1] A 200 mL reaction vessel equipped with a stirrer, thermometer, and air inlet tube was charged with 36.4 parts by mass of IPDI, 21.8 parts by mass of HPA, 28.1 parts by mass of Plaxel FA-2D, 13.4 parts by mass of Kuraray Polyol, 0.04 parts by mass of MQ, and 0.3 parts by mass of Glec TL, and reacted at 80°C for 5 hours to obtain a urethane acrylate oligomer (hereinafter also referred to as "urethane acrylate 1").

[0067] [Synthesis Examples 2, 3, 5, 6] Urethane acrylates 2, 3, 5, and 6 were synthesized in the same manner as in Synthesis Example 1, except that the raw materials shown in Table 1 were used in the amounts (parts by mass) shown in the table. Details of the raw materials in Table 1 are shown in Table 2.

[0068] [Synthesis Example 4] A 200 mL reaction vessel equipped with a stirrer, a thermometer, and an air inlet tube was charged with 27.1 parts by mass of IPDI, 23.3 parts by mass of HPA, 24.3 parts by mass of Kuraray Polyol, 0.04 parts by mass of MQ, and 0.3 parts by mass of Grec TL, and reacted at 80° C. for 5 hours to synthesize a urethane acrylate oligomer (hereinafter also referred to as “urethane acrylate 4”). Then, 25.0 parts by mass of 2-EHA was added to prepare a urethane acrylate oligomer solution.

[0069] [Table 1]

[0070] [Table 2]

[0071] [Example 1] In a container, 6 parts by mass of Omnirad 184, 0.5 parts by mass of Omnirad TPO, 0.02 parts by mass of hydroquinone, 28 parts by mass of 2-EHA, 8.5 parts by mass of Viscoat #230, and 5 parts by mass of Aronix M400 were added and thoroughly stirred with a disperser. 50 parts by mass of the urethane acrylate 1 obtained in Synthesis Example 1, 0.05 parts by mass of DOWSIL, 0.1 parts by mass of Efka, 0.5 parts by mass of TINUVIN 400, and 1 part by mass of TINUVIN 123 were added thereto and thoroughly stirred to prepare an active energy ray curable composition.

[0072] [Examples 2 to 8 and Comparative Examples 1 to 7] Each active energy ray-curable composition was prepared in the same manner as in Example 1, except that the types and amounts of each component were changed as shown in Table 3 below. The numerical values ​​in the columns for each component in Table 3 indicate parts by mass. The explanations of each component listed in Table 3 are shown in Table 4.

[0073] [Preparation of coated test panels] A heavy calcium silicate board (specific gravity 1.2) was heated to a board surface temperature of 40-45°C using a hot air dryer (hot air temperature 100°C), and a composition obtained by mixing and stirring "C-10 Sealer 3X-W" (manufactured by Chugoku Toryo Co., Ltd.), "C-10NY Additive" (manufactured by Chugoku Toryo Co., Ltd.), and "Urethane Thinner BX" (manufactured by Chugoku Toryo Co., Ltd.) in a mass ratio of 100:35:100 was applied at a coating amount of 90 g / m 2 The paint was applied with an air spray so that the coating became smooth, and then dried at 23°C for 3 minutes. After that, the paint was dried in a hot air dryer (hot air temperature 80°C) for 10 minutes to prepare a sealer-coated panel.

[0074] Next, a composition obtained by mixing and stirring "EP Coat No. 300-70 White" (manufactured by Chugoku Paint Co., Ltd.), "Hardener 73-E" (manufactured by Chugoku Paint Co., Ltd.), and "Urethane Thinner A" (manufactured by Chugoku Paint Co., Ltd.) in a mass ratio of 80:10:80 was applied on the sealer-coated plate in an amount of 150 g / m. 2 The paint was then applied with an air spray so that the paint became smooth, and then dried for 10 minutes in a hot air dryer (hot air temperature 80°C) to create an undercoat painted panel.

[0075] The active energy ray-curable compositions obtained in Examples 1 to 8 or Comparative Examples 1 to 7 were applied to the undercoated plate in an amount of 45 g / m using a sponge roll coater ("UV-N-1", manufactured by Mochizuki Machine Works, Ltd.). 2 The coating was applied so that the cumulative light intensity was 500 mJ / cm using a UV irradiator ("Conveyor-type UV device" manufactured by GS Yuasa Corporation) and a high-pressure mercury lamp (80 W / cm). 2 A test plate with a coating was prepared by irradiating the plate with ultraviolet light so that the coating film was

[0076] <Adhesion> In order to evaluate the adhesion of the coating film to the heavy calcium silicate board (exterior building material), the test was carried out as follows based on JIS K 5600-5-6;1999. Specifically, a cross-cut test specimen was prepared by making 25 squares of 4 mm width (scratches reaching the heavy calcium silicate board) on the coating surface of each coating-coated test board with a cutter, and "Sellotape (registered trademark)" was attached to this coating surface, and then the tape was peeled off. The adhesion of the coating film was evaluated according to the following evaluation criteria based on the number of remaining squares of the coating film remaining on the heavy calcium silicate board.

[0077] Evaluation criteria ○: 24 or more remaining squares △: Remaining squares are 20 or more but less than 24 × : Less than 20 spaces remaining

[0078] <Hot water resistance> In order to evaluate the water resistance of the coating film, a hot water resistance test was conducted. Specifically, each coated test plate was immersed in hot water at 60°C for 240 hours, then removed from the hot water, and the coating surface was lightly wiped. The adhesion of the coating film after immersion in hot water was evaluated according to the following evaluation criteria in the same manner as the above-mentioned adhesion test, except that the test specimens were used.

[0079] Evaluation criteria ◎: 25 remaining squares ○: 24 or more remaining squares △: Remaining squares are 20 or more but less than 24 × : Less than 20 spaces remaining

[0080] <Weather resistance> In order to evaluate the weather resistance of the coating film, accelerated weather resistance tests were performed using the coated test panels with an Eye Super UV tester. Specifically, the weather resistance tests were performed under the following conditions. Testing machine: Eye Super UV Tester (Iwasaki Electric Co., Ltd., filter: WJ100-SUV, irradiance on coating surface: 75 mW / cm 2 , wavelength range; 295~450nm) Test time: 1500 hours Test cycle: 4 hours of irradiation → 4 hours of condensation (30-second shower before and after condensation) Average humidity: 50% when irradiated, 98% when condensed, Black panel temperature: 63°C when irradiated, 30°C when condensed

[0081] The appearance of the coating film was visually inspected before and after the weather resistance test, and was evaluated according to the following evaluation criteria.

[0082] Visual appearance evaluation criteria ○: No abnormalities in appearance △: Abnormality in part of the coating ×: Abnormality on the entire coating

[0083] The gloss (initial gloss) of the coating film before the weather resistance test was measured using a "GLOSSMETER" (manufactured by Murakami Color Research Laboratory Co., Ltd.). The gloss of the coating film after the weather resistance test was measured in the same manner, and the gloss retention of the coating film after the test was calculated from these values, with the gloss value before the weather resistance test as the standard. The gloss retention was evaluated according to the following evaluation criteria. Furthermore, the b* value of the coating film before and after the weather resistance test was measured using a spectrophotometer ("JP7100F", manufactured by JUKI Electronics Co., Ltd.), and the difference (Δb*) of the coating film before and after the weather resistance test was evaluated according to the following evaluation criteria.

[0084] Evaluation criteria for gloss retention ◎: Gloss retention is 90% or more ○: Gloss retention is 85% or more △: Gloss retention is between 70% and 85% ×: Gloss retention is less than 70%

[0085] ·Evaluation criteria for Δb* ○: Δb* is less than 1 △: Δb* is between 1 and 3 × : Δb* is 3 or more

[0086] [Table 3]

[0087]

Table 4

Claims

1. A urethane (meth)acrylate (A) having no isocyanurate skeleton, which is obtained using isophorone diisocyanate (a1) and a (meth)acrylate monomer (a2) having a hydroxyl group and a photopolymerizable unsaturated group; (Meth)acrylate monomer (B), and Photopolymerization initiator (C) An active energy ray-curable composition for exterior building materials comprising: The (meth)acrylate monomer (B) is a monofunctional (meth)acrylate compound, and a di- or higher functional (meth)acrylate compound, The content of the monofunctional (meth)acrylate compound is 10 to 65% by mass based on 100% by mass of the nonvolatile content of the active energy ray-curable composition for exterior building materials, When the (meth)acrylate monomer (B) contains a polyoxyalkylene-modified (meth)acrylate (b1), the content of the (meth)acrylate (b1) is 15% by mass or less based on 100% by mass of the nonvolatile content of the composition. An active energy ray-curable composition for exterior building materials.

2. The composition according to claim 1 , wherein the urethane (meth)acrylate (A) and the (meth)acrylate monomer (B) do not have a polyoxyalkylene structure.

3. The composition according to claim 1 or 2, which is for use in a paint.

4. A coating film formed from the composition according to any one of claims 1 to 3.

5. A coated substrate comprising a substrate and the coating of claim 4.

6. A method for producing a substrate with a coating film, comprising the steps of providing the composition according to any one of claims 1 to 3 on at least a part of a substrate, and then irradiating the substrate with active energy rays.

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