Surface coating agent composition of curable composition and construction method using the same

Abstract

To provide a surface coating agent composition of a curable composition which imparts excellent contamination prevention property and matting property to the surface of the curable composition while having excellent elasticity, and a construction method for forming a cured film of the surface coating agent composition on the surface of the curable composition.SOLUTION: There are provided a surface coating agent composition of a curable composition that contains (A) a first isocyanate group-containing (meth)acrylic urethane resin, (B) a second isocyanate group-containing (meth)acrylic urethane resin, and (C) an organic solvent, wherein (A) the first isocyanate group-containing (meth)acrylic urethane resin is a reactant of an organic isocyanate compound containing a modified product of organic polyisocyanate and an active hydrogen-containing compound containing an isocyanate group reactive functional group-containing (meth)acrylic resin, and (B) the second isocyanate group-containing (meth)acrylic urethane resin is a reactant of an organic isocyanate compound containing no modified product of organic polyisocyanate and an active hydrogen-containing compound containing an isocyanate group reactive functional group-containing (meth)acrylic resin; and a construction method for coating or spraying the surface coating agent composition onto the surface of the curable composition, and forming a cured film on the surface of the curable composition.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a surface coating composition for a curable composition that has excellent stretchability and imparts excellent stain resistance and matte properties to the surface of the curable composition, and to an application method using the same. [Background technology]

[0002] Curable compositions such as sealant compositions, waterproofing compositions, and coating compositions containing curable resins such as polyurethane resins and modified silicone resins are widely used for the purpose of waterproofing and surface protection of buildings and civil engineering structures. After these curable compositions are poured or applied to a construction site, if dust or dirt adheres to the composition during curing, the surface will become contaminated, resulting in design defects.

[0003] Furthermore, matte materials are often used for building and civil engineering structure components to create a subdued texture, and sand-like (sand-sprinkled or sandstone-like) materials are often used to create a luxurious feel. If a glossy curable composition is used for such components, the gloss may stand out in those areas, resulting in design defects.

[0004] To solve this problem, there is a method of improving the contamination resistance of the curable composition surface by applying or spraying a surface coating composition onto the surface of the curable composition (for example, Patent Document 1). Also, there is a method of blending an amine into the curable composition to reduce the gloss of the curable composition surface (for example, Patent Document 2).

[0005] Patent Document 1 discloses a technology for preventing adhesion of dust and other particles to the sealant surface and improving the contamination resistance of the sealant surface by applying a solution of polyisocyanate urethane prepolymer made from raw materials such as polyether polyol, trimethylolpropane, and polycaprolactone triol to the surface of a curable composition such as a polyurethane sealant or modified silicone sealant, thereby forming a polyurethane coating film on the sealant surface. However, in order to prevent contamination of the surface of a curable composition such as a sealant, a surface coating composition that exhibits sufficient contamination prevention immediately after pouring is preferred, and the surface coating composition of Patent Document 1 was not necessarily satisfactory. Furthermore, curable compositions used in joints that undergo expansion and contraction displacement, such as working joints, are curable compositions that can follow expansion and contraction displacement, and surface coating compositions used in such areas are also required to have the ability to follow expansion and contraction displacement.

[0006] Patent Document 2 discloses a technique for imparting matte properties to the surface of a curable composition by blending an amine into the curable composition containing a crosslinkable silyl group-containing resin. However, when blending an amine to impart matte properties, there is a risk that it may take time for the matte properties to appear at low temperatures, and blending an epoxy compound to improve adhesion to an adherend may increase the viscosity of the curable composition, which limits the design of the curable composition. Therefore, a new attempt to impart matte properties to the surface of a curable composition is desired. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Unexamined Patent Publication No. 1-201386 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-89742 Summary of the Invention [Problem to be solved by the invention]

[0008] In view of the above circumstances, an object of the present invention is to provide a surface coating composition for a curable composition that has excellent stretchability and imparts excellent stain resistance and matte properties to the surface of the curable composition, and to provide an application method for forming a cured film of the surface coating composition on the surface of the curable composition. [Means for solving the problem]

[0009] The gist of the constitution of the surface coating agent composition of the curable composition of the present invention is as follows. [1] (A) a first isocyanate group-containing (meth)acrylic urethane resin, (B) a second isocyanate group-containing (meth)acrylic urethane resin, and (C) an organic solvent; the (A) first isocyanate group-containing (meth)acrylic urethane resin is a reaction product of an organic isocyanate compound including a modified organic polyisocyanate and an active hydrogen-containing compound including an isocyanate group-reactive functional group-containing (meth)acrylic resin; A surface coating agent composition of a curable composition, characterized in that the (B) second isocyanate group-containing (meth)acrylic urethane resin is a reaction product of an organic isocyanate compound that does not contain a modified organic polyisocyanate and an active hydrogen-containing compound that includes an isocyanate group-reactive functional group-containing (meth)acrylic resin. [2] A surface coating agent composition of the curable composition according to [1], characterized in that the modified organic polyisocyanate is a modified organic polyisocyanate having one or more bonds selected from the group consisting of a uretdione bond, an isocyanurate bond, an allophanate bond, a biuret bond, a uretonimine bond, a carbodiimide bond, a urethane bond, and a urea bond. [3] The surface coating agent composition of the curable composition according to [1], characterized in that the (B) second isocyanate group-containing (meth)acrylic urethane resin is a resin in which an organic isocyanate compound that does not contain a modified organic polyisocyanate is pendant on an active hydrogen-containing compound that contains an isocyanate group-reactive functional group-containing (meth)acrylic resin. [4] A surface coating agent composition of the curable composition according to [1], characterized in that the isocyanate group-reactive functional group is one or more functional groups selected from the group consisting of -COOH, -OH, -NH2, -NH and -SH. [5] The surface coating agent composition of the curable composition according to [1], characterized in that the blending ratio of the (A) first isocyanate group-containing (meth)acrylic urethane resin and the (B) second isocyanate group-containing (meth)acrylic urethane resin is 10 / 90 to 90 / 10, in terms of the number of moles of isocyanate groups in the (B) second isocyanate group-containing (meth)acrylic urethane resin relative to the number of moles of isocyanate groups in the (A) first isocyanate group-containing (meth)acrylic urethane resin. [6] The surface coating agent composition of the curable composition according to [1], characterized in that the total amount of the (A) first isocyanate group-containing (meth)acrylic urethane resin and the (B) second isocyanate group-containing (meth)acrylic urethane resin is 1 to 70 mass % of the surface coating agent composition. [7] The surface coating agent composition of the curable composition according to [1], wherein the (C) organic solvent contains 5 to 70 mass % of a hydrocarbon organic solvent having a boiling point (initial boiling point) of 150°C or higher. [8] The surface coating composition of the curable composition according to [1], further comprising a matting agent. [9] The surface coating composition of the curable composition according to [8], wherein the matting agent is one or more matting agents selected from the group consisting of polyolefins, oxidized polyolefins, and silica.

[10] A composition comprising (A) a first isocyanate group-containing (meth)acrylic urethane resin, (B) a second isocyanate group-containing (meth)acrylic urethane resin, and (C) an organic solvent, wherein the (A) first isocyanate group-containing (meth)acrylic urethane resin is a reaction product of an organic isocyanate compound containing a modified organic polyisocyanate and an active hydrogen-containing compound containing an isocyanate group-reactive functional group-containing (meth)acrylic resin, and the (B) second isocyanate group-containing (meth)acrylic urethane resin is a reaction product of an organic isocyanate compound containing a modified organic polyisocyanate and an active hydrogen-containing compound containing an isocyanate group-reactive functional group-containing (meth)acrylic resin. A method for application of a curable composition, comprising applying or spraying a surface coating composition, which is a reaction product of an organic isocyanate compound not containing an isocyanate group and an active hydrogen-containing compound including a (meth)acrylic resin having an isocyanate group-reactive functional group, onto the surface of the curable composition, thereby forming a cured film on the surface of the curable composition. [Effects of the Invention]

[0010] According to an embodiment of the surface coating agent composition of the curable composition of the present invention, the composition contains (A) a first isocyanate group-containing (meth)acrylic urethane resin, (B) a second isocyanate group-containing (meth)acrylic urethane resin, and (C) an organic solvent, wherein the (A) first isocyanate group-containing (meth)acrylic urethane resin is a reaction product of an organic isocyanate compound containing a modified organic polyisocyanate and an active hydrogen-containing compound containing an isocyanate group-reactive functional group-containing (meth)acrylic resin, and the (B) second isocyanate group-containing (meth)acrylic urethane resin is a reaction product of an organic isocyanate compound not containing a modified organic polyisocyanate and an active hydrogen-containing compound containing an isocyanate group-reactive functional group-containing (meth)acrylic resin, thereby providing a surface coating agent composition of the curable composition that has excellent elasticity and excellent stain resistance to the surface of the curable composition.The surface coating agent composition of the curable composition of the present invention can further contain a matting agent, which can provide a matting effect in addition to excellent elasticity and stain resistance to the surface of the curable composition.

[0011] According to an embodiment of the surface coating agent composition for a curable composition of the present invention, the modified organic polyisocyanate is a modified organic polyisocyanate having one or more bonds selected from the group consisting of a uretdione bond, an isocyanurate bond, an allophanate bond, a biuret bond, a uretonimine bond, a carbodiimide bond, a urethane bond, and a urea bond, and thus the surface coating agent composition for a curable composition can exhibit excellent contamination prevention properties while having excellent elasticity.

[0012] According to an embodiment of the surface coating agent composition of the curable composition of the present invention, the (B) second isocyanate group-containing (meth)acrylic urethane resin is a resin in which an organic isocyanate compound that does not contain a modified organic polyisocyanate is pendant on an active hydrogen-containing compound that includes an isocyanate group-reactive functional group-containing (meth)acrylic resin, and therefore the surface of the curable composition can be more reliably prevented from being contaminated while maintaining excellent elasticity.

[0013] According to an embodiment of the surface coating agent composition of the curable composition of the present invention, the blending ratio of the (A) first isocyanate group-containing (meth)acrylic urethane resin to the (B) second isocyanate group-containing (meth)acrylic urethane resin is 10 / 90 to 90 / 10, in terms of the number of moles of isocyanate groups in the (A) first isocyanate group-containing (meth)acrylic urethane resin to the number of moles of isocyanate groups in the (B) second isocyanate group-containing (meth)acrylic urethane resin, thereby enabling the curable composition to have excellent elasticity while more reliably exhibiting excellent contamination prevention properties on the surface of the curable composition.

[0014] According to an embodiment of the surface coating composition of the curable composition of the present invention, the total amount of the (A) first isocyanate group-containing (meth)acrylic urethane resin and the (B) second isocyanate group-containing (meth)acrylic urethane resin is 1 to 70 mass % in the surface coating composition, whereby the drying properties of the surface coating composition are optimized, and a cured film of the surface coating composition can be reliably formed on the surface of the curable composition even during curing of the curable composition.

[0015] According to an embodiment of the surface coating agent composition of the curable composition of the present invention, the (C) organic solvent contains 5 to 70 mass % of a hydrocarbon organic solvent having a boiling point (initial boiling point) of 150°C or higher, thereby improving the masking tape peelability of the surface coating agent composition of the curable composition.

[0016] According to an embodiment of the application method using the surface coating composition of the curable composition of the present invention, the surface coating composition contains (A) a first isocyanate group-containing (meth)acrylic urethane resin, (B) a second isocyanate group-containing (meth)acrylic urethane resin, and (C) an organic solvent, wherein the (A) first isocyanate group-containing (meth)acrylic urethane resin is a reaction product of an organic isocyanate compound containing a modified organic polyisocyanate and an active hydrogen-containing compound containing a (meth)acrylic resin containing an isocyanate group-reactive functional group, and the (B) second isocyanate group-containing (meth)acrylic urethane resin is a reaction product of an organic isocyanate compound not containing a modified organic polyisocyanate and an active hydrogen-containing compound containing a (meth)acrylic resin containing an isocyanate group-reactive functional group. By applying or spraying the surface coating composition onto the surface of the curable composition and forming a cured film on the surface of the curable composition, the cured film formed on the surface of the curable composition has excellent elasticity and can impart excellent contamination resistance to the surface of the curable composition. DETAILED DESCRIPTION OF THE INVENTION

[0017] The surface coating composition of the curable composition of the present invention and the application method using the surface coating composition of the curable composition will be described in detail below.

[0018] The surface coating agent composition of the curable composition of the present invention comprises (A) a first isocyanate group-containing (meth)acrylic urethane resin, (B) a second isocyanate group-containing (meth)acrylic urethane resin, and (C) an organic solvent, wherein the (A) first isocyanate group-containing (meth)acrylic urethane resin is a reaction product of an organic isocyanate compound containing a modified organic polyisocyanate and an active hydrogen-containing compound containing a (meth)acrylic resin containing an isocyanate group-reactive functional group, and the (B) second isocyanate group-containing (meth)acrylic urethane resin is a reaction product of an organic isocyanate compound not containing a modified organic polyisocyanate and an active hydrogen-containing compound containing a (meth)acrylic resin containing an isocyanate group-reactive functional group. The surface coating agent composition of the curable composition of the present invention is a surface coating agent composition applied to the surface of the curable composition. According to an embodiment of the surface coating agent composition of the curable composition of the present invention, the surface coating agent composition of the curable composition contains (A) a first isocyanate group-containing (meth)acrylic urethane resin, (B) a second isocyanate group-containing (meth)acrylic urethane resin, and (C) an organic solvent, wherein the (A) first isocyanate group-containing (meth)acrylic urethane resin is a reaction product of an organic isocyanate compound containing a modified organic polyisocyanate and an active hydrogen-containing compound containing a (meth)acrylic resin containing an isocyanate group-reactive functional group, and the (B) second isocyanate group-containing (meth)acrylic urethane resin is a reaction product of an organic isocyanate compound not containing a modified organic polyisocyanate and an active hydrogen-containing compound containing a (meth)acrylic resin containing an isocyanate group-reactive functional group, thereby making it possible to obtain a surface coating agent composition of the curable composition that has excellent elasticity and imparts excellent contamination prevention properties to the surface of the curable composition.

[0019] Each component of the surface coating composition of the curable composition of the present invention will be described in detail below.

[0020] <(A) First Isocyanate Group-Containing (Meth)acrylic Urethane Resin> (A) The first isocyanate group-containing (meth)acrylic urethane resin is a reaction product of an organic isocyanate compound containing a modified organic polyisocyanate and an active hydrogen-containing compound containing a (meth)acrylic resin containing an isocyanate group-reactive functional group. The reaction product of an organic isocyanate compound containing a modified organic polyisocyanate and an active hydrogen-containing compound containing a (meth)acrylic resin containing an isocyanate group-reactive functional group (hereinafter sometimes referred to as a "first isocyanate group-containing urethane prepolymer") is obtained by reacting an organic isocyanate compound containing a modified organic polyisocyanate with an active hydrogen-containing compound containing a (meth)acrylic resin containing an isocyanate group-reactive functional group in a molar ratio of isocyanate group / active hydrogen of 1.0. The first isocyanate group-containing urethane prepolymer can be reacted all at once or sequentially within a range of 1.2 or more to prevent the viscosity of the first isocyanate group-containing urethane prepolymer from increasing and thereby reducing the workability of the surface coating composition, and 10 or less to reduce the amount of carbon dioxide gas generated by the reaction of the isocyanate groups with water and prevent foaming during curing, so that isocyanate groups remain in the first isocyanate group-containing urethane prepolymer.

[0021] The isocyanate group content in the first isocyanate group-containing urethane prepolymer is preferably in the range of 1% by mass or more to prevent the viscosity of the first isocyanate group-containing urethane prepolymer from increasing and reducing the workability of the surface coating composition, and 15% by mass or less to reduce the amount of carbon dioxide gas generated by the reaction of the isocyanate groups with water and prevent foaming during curing.

[0022] The number average molecular weight of the first isocyanate group-containing urethane prepolymer is preferably 300 or more, more preferably 300 to 10,000, even more preferably 300 to 5,000, and particularly preferably 300 to 3,000.

[0023] In the present invention, the number average molecular weight and the weight average molecular weight described below are values ​​measured by gel permeation chromatography (GPC) in terms of polystyrene. Specific measurement conditions are shown below. Device name: HLC-8320GPC (Tosoh Corporation) Eluent:THF Temperature: 40℃ Detector: RI

[0024] The first isocyanate group-containing urethane prepolymer can be produced by a conventionally known method. Specifically, a reaction vessel made of glass, stainless steel, or the like is charged with an organic isocyanate compound containing a modified organic polyisocyanate and an active hydrogen-containing compound containing a (meth)acrylic resin containing an isocyanate group-reactive functional group, and the mixture is reacted with stirring at 50 to 120°C, using an organic solvent or a reaction catalyst as needed. Since the viscosity of the first isocyanate group-containing urethane prepolymer increases when the isocyanate group reacts with moisture or other water, it is preferable to replace the atmosphere in the vessel with nitrogen gas beforehand or to carry out the reaction under a nitrogen gas stream.

[0025] As the organic solvent, the same organic solvents as (C) described below can be used.

[0026] Examples of reaction catalysts that can be used include salts of metals such as zinc, tin, zirconium, bismuth, cobalt, manganese, and iron with organic acids such as octylic acid and naphthenic acid, salts of organic metals such as tetra-n-butoxytitanium, dibutyltin dilaurate, and dioctyltin dilaurate with organic acids, and organic amines such as triethylenediamine, triethylamine, tri-n-butylamine, DBU, and DBE, and salts thereof. These may be used alone or in combination of two or more.

[0027] Organic isocyanate compounds including modified organic polyisocyanates The organic isocyanate compound is a compound having one or more isocyanate groups in the molecule. Specific examples include organic polyisocyanates, modified organic polyisocyanates, and organic monoisocyanates, and the organic isocyanate compound includes modified organic polyisocyanates.

[0028] Organic polyisocyanates are compounds that have two or more isocyanate groups in the molecule. Specifically, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, etc. Toluene polyisocyanate, diphenylmethane polyisocyanates such as 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 2,2'-diphenylmethane diisocyanate, 1,2-phenylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4,6-trimethylphenyl-1,3-diisocyanate, and 2,4,6-triisopropylphenyl-1,3 phenylene polyisocyanates such as 1,4-naphthalene diisocyanate and 1,5-naphthalene diisocyanate; aromatic polyisocyanates such as chlorophenylene-2,4-diisocyanate, 4,4'-diphenyl ether diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, and 3,3'-dimethoxydiphenyl-4,4'-diisocyanate. Other examples include aliphatic polyisocyanates such as 1,6-hexamethylene diisocyanate, 1,5-pentamethylene diisocyanate, 1,4-tetramethylene diisocyanate, 2,2,4-trimethyl-1,6-hexamethylene diisocyanate, 2,4,4-trimethyl-1,6-hexamethylene diisocyanate, decamethylene diisocyanate, and lysine diisocyanate; aromatic aliphatic polyisocyanates such as o-xylylene diisocyanate, m-xylylene diisocyanate, and p-xylylene diisocyanate; and alicyclic polyisocyanates such as 1,4-cyclohexyl diisocyanate, isophorone diisocyanate, hydrogenated toluene diisocyanate, hydrogenated xylylene diisocyanate, and hydrogenated diphenylmethane diisocyanate. Further examples include polymeric isocyanates such as polymethylene polyphenyl polyisocyanate, crude toluene diisocyanate, etc. These organic polyisocyanates may be used alone or in combination of two or more.

[0029] Among these organic polyisocyanates, organic polyisocyanates containing at least one of aliphatic polyisocyanates, araliphatic polyisocyanates, and alicyclic polyisocyanates are preferred in terms of improving the weather resistance of the surface coating composition.

[0030] The modified organic polyisocyanate is obtained by modifying the above-mentioned organic polyisocyanate or a mixture of an organic polyisocyanate and an organic monoisocyanate described below, and is a compound having at least one of uretdione bond, isocyanurate bond, allophanate bond, biuret bond, uretonimine bond, carbodiimide bond, urethane bond, and urea bond in the molecule and having two or more isocyanate groups in the molecule. These modified organic polyisocyanates may be used alone or in combination of two or more.

[0031] Among these modified organic polyisocyanates, modified organic polyisocyanates containing at least one of modified aliphatic polyisocyanates, modified araliphatic polyisocyanates, and modified alicyclic polyisocyanates are preferred in terms of improving the weather resistance of the surface coating composition.Moreover, as the modified organic polyisocyanate, modified organic polyisocyanates having an isocyanurate bond are preferred.

[0032] The organic monoisocyanate is a compound having one isocyanate group in the molecule. Specific examples include n-butyl monoisocyanate, n-hexyl monoisocyanate, n-hexadecyl monoisocyanate, n-octadecyl monoisocyanate, p-isopropylphenyl monoisocyanate, and p-benzyloxyphenyl monoisocyanate. These organic monoisocyanates may be used alone or in combination of two or more. Since the organic monoisocyanate exhibits excellent formability of the cured film of the surface coating agent composition, it is preferable to use it in combination with a modified organic polyisocyanate or a mixture of a modified organic polyisocyanate and an organic polyisocyanate.

[0033] Active hydrogen-containing compounds including (meth)acrylic resins containing isocyanate-reactive functional groups Specific examples of active hydrogen-containing compounds containing isocyanate-reactive functional groups include resins in which an isocyanate-reactive functional group is bonded to the (meth)acrylic resin skeleton (the main chain of the (meth)acrylic resin) and / or the terminal of the (meth)acrylic resin. The isocyanate-reactive functional group is preferably at least one of -COOH, -OH, -NH, -NH, and -SH. In the present invention, "(meth)acrylic resin" means "acrylic resin and / or methacrylic resin."

[0034] Examples of the (meth)acrylic resin skeleton structure include those obtained by copolymerizing a (meth)acrylic monomer and an ethylenically unsaturated compound other than a (meth)acrylic monomer in the presence or absence of a solvent by a radical polymerization method such as batch or continuous polymerization.

[0035] Examples of (meth)acrylic monomers include hydroxyl group-containing (meth)acrylic monomers and hydroxyl group-free (meth)acrylic monomers. Hydroxyl group-containing (meth)acrylic monomers are (meth)acrylic monomers having at least one hydroxyl group in the molecule, such as hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate; mono(meth)acrylates of polyhydric alcohols such as pentaerythritol tri(meth)acrylate, glycerin mono(meth)acrylate, pentaerythritol di(meth)acrylate monostearate, dipentaerythritol penta(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, and polypropylene glycol mono(meth)acrylate; and polyhydric (meth)acrylates with residual hydroxyl groups. These compounds may be used alone or in combination of two or more.

[0036] Examples of the (meth)acrylic monomer not containing a hydroxyl group include (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, benzyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, tridecyl (meth)acrylate, ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,3- Examples of (meth)acrylic acid ester compounds include butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, glycidyl tri(meth)acrylate, and trimethylolpropane tri(meth)acrylate. These compounds may be used alone or in combination of two or more. In the present invention, "(meth)acrylate" means "acrylate and / or methacrylate." In addition, in the present invention, "(meth)acrylic acid" means "acrylic acid and / or methacrylic acid."

[0037] Examples of ethylenically unsaturated compounds other than (meth)acrylic monomers include vinyl compounds such as ethylene, propylene, isobutylene, butadiene, chloroprene, styrene, chlorostyrene, 2-methylstyrene, and divinylbenzene.

[0038] The active hydrogen-containing compound containing the isocyanate group-reactive functional group-containing (meth)acrylic resin includes, in addition to the above-mentioned isocyanate group-reactive functional group-containing (meth)acrylic resin, an isocyanate group-reactive functional group-containing compound other than the isocyanate group-reactive functional group-containing (meth)acrylic resin. Active hydrogen-containing compounds can be used.

[0039] Examples of active hydrogen-containing compounds containing isocyanate group-reactive functional groups other than (meth)acrylic resins containing isocyanate group-reactive functional groups include polymer polyols, polymer monools, low-molecular-weight polyols, low-molecular-weight monools, and silane compounds containing isocyanate group-reactive functional groups. These active hydrogen-containing compounds other than (meth)acrylic resins containing isocyanate group-reactive functional groups may be used alone or in combination of two or more. When at least one of polymer polyols, polymer monools, low-molecular-weight polyols, low-molecular-weight monools, and silane compounds containing isocyanate group-reactive functional groups is used in combination, the blending ratio of the (meth)acrylic resin containing isocyanate group-reactive functional groups is preferably 30% by mass or more, and particularly preferably 50% by mass or more, of the active hydrogen-containing compounds including the (meth)acrylic resin containing isocyanate group-reactive functional groups. In the present invention, "polymer" refers to "a compound having a number-average molecular weight of 1,000 or more," and "low-molecular-weight" refers to "a compound having a number-average molecular weight of less than 1,000."

[0040] Specific examples of polymer polyols include polyester polyols, polycarbonate polyols, polyoxyalkylene polyols, hydrocarbon polyols, animal and plant polyols, and copolyols thereof.

[0041] The number average molecular weight of the polymer polyol is preferably 1,000 to 30,000, more preferably 1,000 to 20,000, and particularly preferably 1,000 to 10,000. The weight average molecular weight of the polymer polyol is preferably 1,500 to 50,000, more preferably 2,000 to 40,000, and particularly preferably 2,000 to 20,000.

[0042] Examples of polyester polyols include polycarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid, terephthalic acid, isophthalic acid, orthophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, hexahydroorthophthalic acid, naphthalenedicarboxylic acid, and trimellitic acid, anhydrides of these polycarboxylic acids, and alkyl esters of these polycarboxylic acids such as methyl esters and ethyl esters, and polyesters containing at least one of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3 Examples of polyester polyols include polyester polyols obtained by reacting one or more low-molecular-weight polyols such as 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanedimethanol, an ethylene oxide or propylene oxide adduct of bisphenol A, trimethylolpropane, glycerin, and pentaerythritol. Examples of polyester polyols include polyesteramide polyols obtained by reacting these carboxylic acids and low-molecular-weight polyols with one or more low-molecular-weight polyamines such as butylenediamine, hexamethylenediamine, xylylenediamine, and isophoronediamine, and low-molecular-weight aminoalcohols such as monoethanolamine and diethanolamine. Further, examples of polyester polyols include lactone-based polyester polyols obtained by ring-opening polymerization of cyclic ester (lactone) monomers such as ε-caprolactone and γ-valerolactone using low molecular weight polyols, low molecular weight polyamines, and low molecular weight amino alcohols as initiators.

[0043] Examples of polycarbonate polyols include polyols obtained by the dehydrochlorination reaction of the low-molecular-weight polyols used in the synthesis of the above-mentioned polyester polyols with phosgene, or by the transesterification reaction of the above-mentioned low-molecular-weight polyols with diethylene carbonate, dimethyl carbonate, diethyl carbonate, or diphenyl carbonate.

[0044] Examples of polyoxyalkylene polyols include the low molecular weight polyols, low molecular weight polyamines, and low molecular weight amino alcohols used in the synthesis of the above-mentioned polyester polyols, as well as polyoxyethylene polyols, polyoxypropylene polyols, polyoxybutylene polyols, polyoxytetramethylene polyols, and poly-(oxyethylene)-(oxypropylene)-random or block copolymer polyols obtained by ring-opening addition polymerization or copolymerization of one or more cyclic ether compounds such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran using one or more sugar-based low molecular weight polyhydric alcohols such as sorbitol, mannitol, sucrose, and glucose; and low molecular weight polyhydric phenols such as bisphenol A and bisphenol F as initiators.Furthermore, examples of polyoxyalkylene polyols include polyester ether polyols and polycarbonate ether polyols using the above-mentioned polyester polyols and polycarbonate polyols as initiators. Examples of polyoxyalkylene polyols include polyols obtained by reacting these various ether polyols with organic isocyanate compounds in an excess of hydroxyl groups relative to isocyanate groups, resulting in hydroxyl groups at the molecular terminals. The number of alcoholic hydroxyl groups in the polyoxyalkylene polyol is 2 or more, preferably 2 to 4, and particularly preferably 2 to 3, on average per molecule.

[0045] Examples of catalysts used in synthesizing polyoxyalkylene polyols include alkali metal compound catalysts such as sodium catalysts and potassium catalysts, cationic polymerization catalysts, composite metal cyanide complex catalysts such as zinc hexacyanocobaltate glyme complexes and diglyme complexes, and phosphazene compound catalysts. Among these catalysts, alkali metal compound catalysts and composite metal cyanide complex catalysts are preferred. Furthermore, polyoxyalkylene polyols synthesized using composite metal cyanide complex catalysts are preferred because they have a low total unsaturation degree and a low viscosity of the polyol.

[0046] The term "polyoxyalkylene polyol" and "polyoxyalkylene monool" as used herein means that 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 95% by mass or more of the portion excluding hydroxyl groups per mole of the molecule is composed of polyoxyalkylene, and the remaining portion may be modified with ester, urethane, polycarbonate, polyamide, polyolefin, etc.

[0047] Examples of hydrocarbon polyols include polyolefin polyols such as polybutadiene polyol and polyisoprene polyol; polyalkylene polyols such as hydrogenated polybutadiene polyol and hydrogenated polyisoprene polyol; and halogenated polyalkylene polyols such as chlorinated polypropylene polyol and chlorinated polyethylene polyol.

[0048] Examples of animal and plant polyols include castor oil polyols and silk fibroin.

[0049] The above-mentioned polymer polyols may be used alone or in combination of two or more kinds.

[0050] Examples of the polymer monool include polyoxyalkylene monools such as polyoxypropylene monools obtained by ring-opening addition polymerization of cyclic ether compounds such as propylene oxide using low-molecular-weight monoalcohols such as methyl alcohol, ethyl alcohol, and propyl alcohol as an initiator. The number-average molecular weight of the polymer monool is preferably 1,000 to 10,000. These polymer monools may be used alone or in combination of two or more.

[0051] Examples of low molecular weight polyols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-2,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 3,5-heptanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, diethylene glycol, and triethylene glycol. Examples of suitable low molecular weight aliphatic polyols include low molecular weight aliphatic polyols such as cyclohexanedimethanol, dipropylene glycol, and tripropylene glycol; low molecular weight alicyclic polyols such as cyclohexanedimethanol and cyclohexanediol; low molecular weight aromatic polyols such as an ethylene oxide (hereinafter sometimes referred to as "EO") adduct of bisphenol A with 2 to 10 moles of EO, which is an adduct of bisphenol A with propylene oxide (hereinafter sometimes referred to as "PO"), and an adduct of bisphenol A with 2 to 8 moles of PO, which is an adduct of bisphenol A with propylene oxide (hereinafter sometimes referred to as "PO"); and low molecular weight polyols having three or more hydroxyl groups such as trimethylolethane, trimethylolpropane, hexitols, pentitols, glycerin, polyglycerin, pentaerythritol, dipentaerythritol, and tetramethylolpropane. These low molecular weight polyols may be used alone or in combination of two or more.

[0052] Examples of low molecular weight monools include aliphatic monoalcohols having 1 to 20 carbon atoms, such as methyl alcohol, ethyl alcohol, and propyl alcohol. These low molecular weight monools may be used alone or in combination of two or more.

[0053] Silane compounds containing isocyanate-reactive functional groups contain organic functional groups (isocyanate-reactive functional groups) in the molecule that are reactive with isocyanate groups and hydrolyzable (crosslinkable) The isocyanate group-reactive functional group is preferably a functional group having active hydrogen because it easily reacts with the organic isocyanate compound. Examples of the isocyanate group-reactive functional group include at least one of the following functional groups: -COOH, -OH, -NH, -NH, and -SH.

[0054] The number of hydrolyzable (crosslinkable) silyl groups contained in one molecule is preferably 1 to 5, and particularly preferably 1 to 3. The hydrolyzable (crosslinkable) silyl group is preferably one represented by the following general formula, from the viewpoint of ease of crosslinking and ease of production.

[0055] [ka] (In the formula, R represents a hydrocarbon group, and is preferably an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, with a methyl group being particularly preferred. When there are multiple Rs, they may be the same or different. The reactive group represented by X is a hydrolyzable group selected from a halogen atom, a hydrogen atom, a hydroxyl group, an alkoxy group, an acyloxy group, a ketoximate group, an amide group, an acid amide group, a mercapto group, an alkenyloxy group, and an aminooxy group, and when there are multiple Xs, they may be the same or different. Of these, X is preferably an alkoxy group, with a methoxy group or an ethoxy group being particularly preferred. a represents an integer of 0, 1, or 2, with 0 or 1 being particularly preferred.)

[0056] Specific examples of compounds having one or more isocyanate-reactive functional groups and one or more hydrolyzable (crosslinkable) silyl groups in the molecule include aminosilane coupling agents and mercaptosilane coupling agents. The organic functional groups of aminosilane coupling agents and mercaptosilane coupling agents have active hydrogen, which makes them preferable because they react relatively easily with the isocyanate groups of organic isocyanate compounds, including modified organic polyisocyanates. These compounds may be used alone or in combination of two or more.

[0057] Specific examples of the aminosilane coupling agent include aminomethyltriethoxysilane, N-(2-aminoethyl)aminomethyltrimethoxysilane, aminomethyldiethoxysilane, N-(2-aminoethyl)methyltributoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminoisobutyltrimethoxysilane, N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, and N-(aminoethyl)-3-amino-2-methylpropyltrimethoxysilane.

[0058] Specific examples of the mercaptosilane coupling agent include 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylethyldimethoxysilane, 3-mercaptopropylethyldiethoxysilane, 3-mercaptopropyldimethylmethoxysilane, 2-mercaptoethylmethyldimethoxysilane, 2-mercaptoethyltrimethoxysilane, and 2-mercaptoethyltriethoxysilane.

[0059] <(B) Second Isocyanate Group-Containing (Meth)acrylic Urethane Resin> (B) The second isocyanate group-containing (meth)acrylic urethane resin is a reaction product of an organic isocyanate compound that does not contain a modified organic polyisocyanate and an active hydrogen-containing compound that contains a (meth)acrylic resin that contains an isocyanate group-reactive functional group. The second isocyanate group-containing (meth)acrylic urethane resin is an isocyanate group-containing (meth)acrylic urethane resin that differs from the first isocyanate group-containing (meth)acrylic urethane resin in that it does not have a chemical structure derived from a modified organic polyisocyanate.

[0060] The second isocyanate group-containing (meth)acrylic urethane resin is not particularly limited as long as it is a reaction product of an organic isocyanate compound that does not contain a modified organic polyisocyanate and an active hydrogen-containing compound that contains a (meth)acrylic resin that contains an isocyanate group-reactive functional group. However, from the viewpoint of being able to more reliably exhibit excellent contamination prevention properties on the surface of the curable composition, it is preferable that the second isocyanate group-containing (meth)acrylic urethane resin be a resin in which an organic isocyanate compound that does not contain a modified organic polyisocyanate is pendant on an active hydrogen-containing compound that contains a (meth)acrylic resin that contains an isocyanate group-reactive functional group. In the present invention, the term "resin in which an organic isocyanate compound containing no modified organic polyisocyanate is pendant on an active hydrogen-containing compound containing an isocyanate group-reactive functional group-containing (meth)acrylic resin" refers to a resin in which an isocyanate group-reactive functional group bonded to the main chain of an active hydrogen-containing compound containing an isocyanate group-reactive functional group-containing (meth)acrylic resin (for example, the main chain of an isocyanate group-reactive functional group-containing (meth)acrylic resin) is reacted with an isocyanate group of an organic isocyanate compound containing no modified organic polyisocyanate, and the resulting organic isocyanate compound containing no modified organic polyisocyanate is bonded to the main chain of an active hydrogen-containing compound containing an isocyanate group-reactive functional group-containing (meth)acrylic resin (for example, in the main chain, not at the terminal, of the isocyanate group-reactive functional group-containing (meth)acrylic resin).

[0061] The reaction product of an organic isocyanate compound that does not contain a modified organic polyisocyanate and an active hydrogen-containing compound that contains an isocyanate group-reactive functional group-containing (meth)acrylic resin (hereinafter, sometimes referred to as the "second isocyanate group-containing (meth)acrylic urethane prepolymer") can be produced by reacting an organic isocyanate compound that does not contain a modified organic polyisocyanate with an active hydrogen-containing compound that contains an isocyanate group-reactive functional group-containing (meth)acrylic resin all at once or sequentially in such a range that the molar ratio of isocyanate group / active hydrogen is greater than 1.0, preferably 1.2 or more to prevent the viscosity of the second isocyanate group-containing (meth)acrylic urethane prepolymer from increasing and reducing the application or sprayability of the surface coating composition, and 10 or less to reduce the amount of carbon dioxide gas generated by the reaction of the isocyanate group with water and prevent foaming during curing, so that the isocyanate group remains in the second isocyanate group-reactive functional group-containing (meth)acrylic urethane prepolymer.

[0062] The isocyanate group content in the second isocyanate group-containing (meth)acrylic urethane prepolymer is preferably in the range of 1% by mass or more to prevent the viscosity of the second isocyanate group-containing (meth)acrylic urethane prepolymer from increasing and reducing the workability of the surface coating composition, and 15% by mass or less to reduce the amount of carbon dioxide gas generated by the reaction of the isocyanate groups with water and prevent foaming during curing.

[0063] The number average molecular weight of the second isocyanate group-containing (meth)acrylic urethane prepolymer is preferably 300 or more, more preferably 300 to 10,000, even more preferably 300 to 5,000, and particularly preferably 300 to 3,000.

[0064] The second isocyanate group-containing (meth)acrylic urethane prepolymer can be produced by a conventionally known method, specifically, by the same method as the above-mentioned first isocyanate group-containing (meth)acrylic urethane prepolymer.

[0065] Organic isocyanate compounds that do not contain modified organic polyisocyanates The organic isocyanate compound may be an organic polyisocyanate or an organic monoisocyanate that can be used in synthesizing the (A) first isocyanate group-containing urethane resin, but does not include modified organic polyisocyanates. The organic isocyanate compound may be used alone or in combination of two or more kinds.

[0066] Among the organic polyisocyanates, organic polyisocyanates containing at least one of aliphatic polyisocyanates, araliphatic polyisocyanates, and alicyclic polyisocyanates are preferred in terms of improving the weather resistance of the surface coating composition.

[0067] Active hydrogen-containing compounds including (meth)acrylic resins containing isocyanate-reactive functional groups Examples of active hydrogen-containing compounds containing isocyanate group-reactive functional groups include (A) active hydrogen-containing compounds containing isocyanate group-reactive functional groups that can be used in synthesizing the first isocyanate group-containing (meth)acrylic urethane resin. Furthermore, (B) isocyanate group-reactive functional group-containing (meth)acrylic resins that can be used in synthesizing the second isocyanate group-containing (meth)acrylic urethane resin are preferably resins in which the isocyanate group-reactive functional groups are bonded to the (meth)acrylic resin skeleton (the main chain of the (meth)acrylic resin (not the terminals of the (meth)acrylic resin, but within the main chain)). Examples of active hydrogen-containing compounds other than isocyanate group-reactive functional group-containing (meth)acrylic resins include polymer polyols, polymer monools, low-molecular-weight polyols, low-molecular-weight monools, and silane compounds containing isocyanate group-reactive functional groups. These active hydrogen-containing compounds other than the isocyanate group-reactive functional group-containing (meth)acrylic resins can be used alone. When at least one of a high molecular weight polyol, a high molecular weight monool, a low molecular weight polyol, a low molecular weight monool, and a silane compound containing an isocyanate group-reactive functional group is used in combination, the blending ratio of the isocyanate group-reactive functional group-containing (meth)acrylic resin is preferably 30 mass % or more, and particularly preferably 50 mass % or more, of the active hydrogen-containing compound including the isocyanate group-reactive functional group-containing (meth)acrylic resin.

[0068] The blending ratio of the (A) first isocyanate group-containing (meth)acrylic urethane resin and the (B) second isocyanate group-containing (meth)acrylic urethane resin is not particularly limited, but in order to more reliably exhibit excellent contamination prevention properties on the surface of the curable composition, the ratio of the number of moles of isocyanate groups in the (B) second isocyanate group-containing (meth)acrylic urethane resin to the number of moles of isocyanate groups in the (A) first isocyanate group-containing (meth)acrylic urethane resin (number of moles of isocyanate groups in the (A) first isocyanate group-containing (meth)acrylic urethane resin / number of moles of isocyanate groups in the (B) second isocyanate group-containing (meth)acrylic urethane resin) is preferably 10 / 90 to 90 / 10, more preferably 20 / 80 to 80 / 20, and particularly preferably 30 / 70 to 70 / 30.

[0069] The total blending amount of (A) the first isocyanate group-containing (meth)acrylic urethane resin and (B) the second isocyanate group-containing (meth)acrylic urethane resin in the surface coating composition is not particularly limited, but is preferably 1 to 70 mass %, particularly preferably 5 to 50 mass %, because this optimizes the drying properties of the surface coating composition and ensures the formation of a cured film of the surface coating composition on the surface of the curable composition even during curing of the curable composition.

[0070] <(C) Organic Solvent> The (C) organic solvent is a component for dissolving the (A) first isocyanate group-containing (meth)acrylic urethane resin, the (B) second isocyanate group-containing (meth)acrylic urethane resin, and the optional modified organic isocyanate compound and additives described below, and for dispersing the optional matting agent described below. The (C) organic solvent is also a diluent that adjusts the viscosity of the surface coating agent composition of the present invention to a level suitable for coating work, and is a component for adjusting the drying properties of the cured film of the surface coating agent composition of the present invention.

[0071] The organic solvent is not particularly limited as long as it is inert and non-reactive with (A) the first isocyanate group-containing (meth)acrylic urethane resin, (B) the second isocyanate group-containing (meth)acrylic urethane resin, modified organic isocyanate compound, matting agent, and additives. Examples of the organic solvent include ester-based organic solvents such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, butyl butyrate, butyl stearate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, γ-butyrolactone, and diethyl malonate; ether-based organic solvents such as diethyl ether, dipropyl ether, dibutyl ether, dioxane, and tetrahydrofuran; and amide-based organic solvents such as N,N-dimethylacetamide and N-methylpyrrolidone. Examples of suitable organic solvents include ketone-based organic solvents such as acetone, methyl ethyl ketone, methyl propyl ketone, diethyl ketone, butyl methyl ketone, methyl isobutyl ketone, cyclohexanone, methylcyclohexanone, isophorone, and acetophenone; and acetate-based organic solvents such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and methyl-1,3-butylene glycol acetate.

[0072] Further, examples of the organic solvent include hydrocarbon organic solvents, such as aliphatic hydrocarbon organic solvents having 15 or less carbon atoms, such as n-hexane, 2-methylpentane, n-heptane, n-octane, 2,2,3-trimethylpentane, 2,2,4-trimethylpentane, n-nonane, 2,2,5-trimethylhexane, decane, dodecane, and pentadecane; Examples of suitable organic solvents include aliphatic hydrocarbon organic solvents having 16 or more carbon atoms, such as cosane, tetracosane, pentacosane, and nonacosane; alicyclic hydrocarbon organic solvents, such as cyclohexane, cyclooctane, cyclodecane, and cyclododecane; and aromatic hydrocarbon organic solvents, such as xylene, ethylbenzene, trimethylbenzene, isopropylbenzene, butylbenzene, diethylbenzene, pentylbenzene, dipentylbenzene, cyclohexylbenzene, naphthalene, tetralin, and biphenyl. These organic solvents may be used alone or in combination of two or more.

[0073] Among these, from the viewpoint of obtaining masking tape peelability of the surface coating composition of the curable composition, it is preferable that the organic solvent contains a hydrocarbon organic solvent having a boiling point (initial boiling point) of 150°C or more, and it is particularly preferable that it contains a hydrocarbon organic solvent having a boiling point (initial boiling point) of 150°C or more and 300°C or less. Furthermore, from the viewpoint of improving masking tape peelability of the surface coating composition of the curable composition, it is preferable that the amount of hydrocarbon organic solvent having a boiling point (initial boiling point) of 150°C or more in the organic solvent is 5 to 70 mass% (i.e., it contains 5 to 70 mass% of hydrocarbon organic solvent having a boiling point (initial boiling point) of 150°C or more and 30 to 95 mass% of organic solvent having a boiling point (initial boiling point) of less than 150°C). From the viewpoint of further improving masking tape peelability, it is preferable that the organic solvent contains a hydrocarbon organic solvent having a boiling point ( It is more preferable that the solvent contains 10 to 60 mass% of hydrocarbon organic solvents having a boiling point (initial boiling point) of 150°C or higher (i.e., 10 to 60 mass% of hydrocarbon organic solvents having a boiling point (initial boiling point) of 150°C or higher, and 40 to 90 mass% of organic solvents having a boiling point (initial boiling point) of less than 150°C), and it is particularly preferable that the solvent contains 15 to 45 mass% of hydrocarbon organic solvents having a boiling point (initial boiling point) of 150°C or higher (i.e., 15 to 45 mass% of hydrocarbon organic solvents having a boiling point (initial boiling point) of 150°C or higher, and 55 to 85 mass% of organic solvents having a boiling point (initial boiling point) of less than 150°C).

[0074] As the hydrocarbon organic solvent having a boiling point (initial boiling point) of 150° C. or higher, an aliphatic hydrocarbon organic solvent or an alicyclic hydrocarbon organic solvent is preferred.

[0075] As the organic solvent having a boiling point (initial boiling point) of less than 150°C, ester-based organic solvents such as ethyl acetate, ketone-based organic solvents such as methyl ethyl ketone, and acetate-based organic solvents such as ethylene glycol monomethyl ether acetate are preferred.

[0076] The amount of organic solvent in the surface coating composition is not particularly limited, but from the viewpoint of optimizing the coatability (applicability or sprayability) of the surface coating composition and the drying properties of the cured film of the surface coating composition, it is preferably 20 to 90 mass %, more preferably 30 to 99 mass %, and particularly preferably 50 to 95 mass %.

[0077] <Modified organic isocyanate compound (optional component)> The surface coating agent composition of the present invention may contain a modified organic isocyanate compound as an optional component, as long as the object of the present invention is not impaired. When the surface coating agent composition of the present invention further contains a modified organic isocyanate compound, the formability of the cured film of the surface coating agent composition is improved and the stickiness of the curable composition surface can be reduced. Examples of modified organic isocyanate compounds include those similar to the modified organic polyisocyanates that can be used in the production of the first isocyanate group-containing (meth)acrylic urethane prepolymer described above. The modified organic isocyanate compound may be contained as a modified organic polyisocyanate that remains unreacted during the production of the first isocyanate group-containing (meth)acrylic urethane prepolymer described above, or the modified organic isocyanate compound may be incorporated when preparing the surface coating agent composition of the present invention.

[0078] Among the modified organic isocyanate compounds, modified aliphatic polyisocyanates, modified aromatic aliphatic polyisocyanates, alicyclic polyisocyanates, etc. are preferred because they improve the weather resistance of the surface coating composition. Modified organic isocyanate compounds containing at least one modified aromatic polyisocyanate are preferred. As the modified organic isocyanate compounds, modified organic isocyanate compounds having an isocyanurate bond are preferred.

[0079] The amount of the modified organic isocyanate compound blended in the surface coating agent composition is preferably 1 to 20% by mass, particularly preferably 2 to 15% by mass. In addition, when an unreacted modified organic polyisocyanate remains as the modified organic isocyanate compound during the production of the first isocyanate group-containing (meth)acrylic urethane prepolymer, the blending amount is calculated as the total amount including the modified organic isocyanate compound blended as an optional component during the production of the surface coating agent composition.

[0080] <Matte agent (optional ingredient)> The surface coating agent composition of the present invention may contain a matting agent as an optional component, if necessary. When the surface coating agent composition of the present invention further contains a matting agent, it can contribute to imparting excellent matte properties to the surface of the curable composition.

[0081] The matting agent may be, for example, a particulate component. Examples of the matting agent material include polyolefins such as polyethylene and polypropylene, oxidized polyolefins, and silica. These matting agents may be used alone or in combination of two or more. Furthermore, the matting agent may be one in which the matting component is dispersed in an organic solvent.

[0082] The average particle size of the matting agent is preferably 0.5 to 10 μm, particularly preferably 1 to 8 μm, from the viewpoint of contributing to imparting excellent matte properties to the surface of the curable composition. The average particle size in the present invention is the numerical value of the median diameter (d50) of the volume-based particle size distribution measured by a laser diffraction scattering method.

[0083] The amount of the matting agent in the surface coating composition is not particularly limited as long as it can impart matting properties to the surface of the curable composition, but from the viewpoint of contributing to an excellent matting effect on the surface of the curable composition without impairing the coatability of the surface coating composition, the amount is preferably 0.5 to 10 mass %, and particularly preferably 1 to 5 mass %, relative to the total amount of (A) the first isocyanate group-containing (meth)acrylic urethane resin and (B) the second isocyanate group-containing (meth)acrylic urethane resin.

[0084] <Additives (optional ingredients)> The surface coating composition of the present invention can contain various additives as optional components, as long as the object of the present invention is not impaired. The additives are added to the surface coating composition to improve various performances of the surface coating composition, such as curing acceleration, weather resistance, adhesion, and defoaming properties. Specific examples of the additives include curing acceleration catalysts, weather stabilizers, adhesion promoters, and defoamers. These additives may be used alone or in combination of two or more.

[0085] The curing-accelerating catalyst is added to promote the formation of a cured film by crosslinking and curing the surface coating composition of the present invention through reaction with an active hydrogen-containing compound (e.g., water such as humidity). The curing-accelerating catalyst can be the same as the reaction catalyst used in the production of the (A) first isocyanate group-containing (meth)acrylic urethane resin and the (B) second isocyanate group-containing (meth)acrylic urethane resin. The curing-accelerating catalyst may be used alone or in combination of two or more. When a curing-accelerating catalyst is used as a reaction catalyst in the production of the (A) first isocyanate group-containing (meth)acrylic urethane resin and the (B) second isocyanate group-containing (meth)acrylic urethane resin, the reaction catalyst remaining in the resin may act as a curing-accelerating catalyst for the surface coating composition.

[0086] The amount of the curing-accelerating catalyst in the surface coating composition is not particularly limited, but is preferably 0.01 to 1 mass %, and particularly preferably 0.05 to 0.5 mass %, relative to the total amount of (A) the first isocyanate group-containing (meth)acrylic urethane resin and (B) the second isocyanate group-containing (meth)acrylic urethane resin.

[0087] The weather resistance stabilizer is added to prevent oxidation, light degradation, and heat degradation of the cured film (coating film) after applying or spraying the surface coating composition, thereby further improving weather resistance and heat resistance. Examples of the weather resistance stabilizer include hindered amine light stabilizers, hindered phenol antioxidants, and ultraviolet absorbers. These weather resistance stabilizers may be used alone or in combination of two or more.

[0088] Examples of the hindered amine light stabilizer include bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, decanedioic acid bis(2,2,6,6-tetramethyl-1(octyloxy)-4-piperidyl)ester, bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, methyl 1,2,2,6,6-pentamethyl-4-piperidylsebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, 1-[2-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]ethyl]-4 ... dimethyl succinate·1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}], N,N'-bis(3-aminopropyl)ethylenediamine-2,4-bis[N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino]-6-chloro-1,3,5-triazine condensate. Furthermore, examples of commercially available hindered amine light stabilizers include Adekastab LA-63P and LA-68LD manufactured by ADEKA Corporation.

[0089] Examples of hindered phenol antioxidants include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propioamide], benzenepropanoic acid 3,5-bis(1,1-dimethylethyl)-4-hydroxy C7-C9 side chain alkyl ester, and 2,4-dimethyl-6-(1-methylpentadecyl)phenol.

[0090] Examples of the ultraviolet absorber include benzotriazole-based ultraviolet absorbers such as 2-(3,5-di-tert-butyl-2-hydroxyphenyl)-5-chlorobenzotriazole; triazine-based ultraviolet absorbers such as 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]phenol; benzophenone-based ultraviolet absorbers such as octabenzone; and benzoate-based ultraviolet absorbers such as 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate.

[0091] Among the above-mentioned weather resistance stabilizers, hindered amine-based light stabilizers and hindered phenol-based antioxidants are preferred because they have a greater effect in improving weather resistance. The amount of the weather resistance stabilizer to be added is preferably 0.1 to 5 mass % relative to the total amount of (A) the first isocyanate group-containing (meth)acrylic urethane resin and (B) the second isocyanate group-containing (meth)acrylic urethane resin. A content of 0.5 to 3 mass % is particularly preferred.

[0092] The adhesion promoter is blended to improve the adhesion between the surface coating composition and the curable composition, and the adhesion between the surface coating composition and the topcoat paint. Examples of the adhesion promoter include an epoxy silane coupling agent and a (meth)acrylic coupling agent. These adhesion promoters may be used alone or in combination of two or more.

[0093] Examples of epoxy silane coupling agents include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane. Examples of (meth)acrylic coupling agents include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane.

[0094] The amount of the adhesion promoter in the surface coating composition is preferably 0.1 to 5 mass %, particularly preferably 0.5 to 3 mass %, relative to the total amount of (A) the first isocyanate group-containing (meth)acrylic urethane resin and (B) the second isocyanate group-containing (meth)acrylic urethane resin.

[0095] The antifoaming agent is blended to reduce foaming that occurs when the surface coating agent composition is applied or sprayed. Examples of the antifoaming agent include silicone-based antifoaming agents, fatty acid ester-based antifoaming agents, higher alcohol-based antifoaming agents such as aliphatic alcohol-based antifoaming agents having 6 or more carbon atoms, and polyether-based antifoaming agents. These antifoaming agents may be used alone or in combination of two or more.

[0096] The amount of the antifoaming agent blended in the surface coating composition is preferably 0.1 to 3 mass %, particularly preferably 0.2 to 2 mass %, based on the total mass of the surface coating composition.

[0097] The method for producing the surface coating agent composition of the present invention is not particularly limited and can be carried out by a known method. Specifically, the method includes charging (A) a first isocyanate group-containing (meth)acrylic urethane resin, (B) a second isocyanate group-containing (meth)acrylic urethane resin, (C) an organic solvent, and, if necessary, a modified organic isocyanate compound, a matting agent, and additives into a mixing vessel equipped with a stirrer made of glass, stainless steel, iron, etc., and stirring and mixing under a stream of inert gas such as nitrogen to produce the surface coating agent composition.

[0098] The curable composition to which the surface coating composition of the present invention is applied or sprayed will now be described. Specific examples of the curable composition include a curable composition containing a resin that cures upon reaction with an active hydrogen-containing compound.

[0099] Specific examples of the curable composition include silicone-based curable compositions, modified silicone-based curable compositions, polyurethane-based curable compositions, and polysulfide-based curable compositions. Among these, modified silicone-based curable compositions, polyurethane-based curable compositions, and polysulfide-based curable compositions are preferred, as they have an excellent balance of physical properties such as modulus, elongation, and tensile strength after curing, and modified silicone-based curable compositions and polyurethane-based curable compositions are particularly preferred.

[0100] These curable compositions include one-component moisture-curable compositions that cure by reacting with moisture in the air, and two-component reactive curable compositions that cure by reacting the base agent with the curing agent. The surface coating composition of the present invention can be used as either a one-component moisture-curable composition or a two-component reactive-curable composition.

[0101] One-component moisture-curable compositions often cure more slowly than two-component reactive curable compositions, and therefore their surfaces become sticky during curing, making them susceptible to contamination due to the adhesion of dust and dirt. When the surface coating composition of the present invention is applied or sprayed onto the surface of a one-component moisture-curable composition, a cured film can be formed on the surface of the curable composition, reducing the stickiness of the surface of the curable composition, making it particularly useful for preventing contamination of the surface of the curable composition.

[0102] The application method for forming a cured film on the surface of a curable composition by applying or spraying the surface coating agent composition of the present invention onto the surface of the curable composition will be described below.

[0103] First, the curable composition is poured or applied to a surface to be adhered, such as a base or a joint. Before pouring or applying the curable composition to the surface to be adhered, a primer may be applied to the surface to be adhered in advance to improve adhesion to the surface to be adhered. When a primer is applied, the composition is allowed to cure for a predetermined time until the primer dries and hardens.

[0104] After casting or applying the curable composition, the surface of the curable composition is smoothed using a spatula, roller, or the like to achieve the desired shape. When casting or applying the curable composition, a protective tape (masking tape) or a protective sheet (polymer masker) may be used as needed to prevent the curable composition from adhering to areas other than the surface to be adhered. Next, the surface coating composition of the present invention is applied or sprayed (sprayed) onto the surface of the curable composition. After applying or spraying (spraying) the surface coating composition, the protective tape or protective sheet is removed before a cured film is formed. Examples of tools for applying the surface coating composition include a brush and a spatula. Examples of tools for spraying (spraying) the surface coating composition include a spray gun, an airbrush, and an aerosol spray. The amount of application of the surface coating composition is not particularly limited as long as it does not impair the object of the present invention, but is preferably 10 to 100 g / m 2 is preferable, and 20 to 80 g / m 2 is particularly preferred.

[0105] When using an aerosol spray as a tool for spraying (spraying) the surface coating composition, known liquefied gas propellants or compressed gas propellants can be used as the propellant. Examples of liquefied gas propellants include LPG (liquefied petroleum gas) such as propane and butane, and alternative chlorofluorocarbon gases such as dimethyl ether (DME), HFC134a, HFC152a, and HF01234Ze. Examples of compressed gas propellants include nitrogen gas, carbon dioxide gas, and nitrous oxide gas. Among these, LPG and dimethyl ether (DME) are preferred for their convenience.

[0106] The curable composition to which the surface coating agent composition of the present invention can be applied specifically includes curable compositions used as sealants, waterproofing materials, and coating materials, and is suitable as the surface coating agent composition of the curable composition used as sealing materials, waterproofing materials, and coating materials for construction or civil engineering.Among these, the curable composition used as a sealant is preferred, the curable composition used as a sealant used in the joint (joint) between components is more preferred, the curable composition used as a sealant used in the joint (joint) between outdoor components is even more preferred, and the curable composition used as a sealant for the working joint, which is the joint (joint) that expands and contracts outdoors, is particularly preferred. [Example]

[0107] The present invention will be described in more detail below with reference to examples, but the present invention should not be construed as being limited to these.

[0108] [Synthesis Example 1] (First isocyanate group-containing acrylic urethane resin solution) While nitrogen gas was flowing into a reaction vessel equipped with a stirrer, a thermometer, a nitrogen seal tube, and a heating / cooling device, 216.2 g of ethyl acetate and 69.0 g of an isocyanurate of isophorone diisocyanate (IPDI) (VESTANAT T1890E, solids content 70 mass%, butyl acetate 30 mass%, NCO content 12 mass%, Evonik Japan Co., Ltd.) were charged, and while stirring, 31.0 g of acrylic polyol A (UH-2041, Toagosei Co., Ltd., hydroxyl value 120 mg KOH / g-resin, glass transition temperature Tg-50°C, number average molecular weight 1,320, weight average molecular weight 2,260, the number of hydroxyl groups calculated from the hydroxyl value and number average molecular weight is 2.8 per molecule) and 0.8 g of dibutyltin dilaurate diluted 10 times with ethyl acetate as a reaction catalyst were charged, and the temperature was raised to 70-80°C. The mixture was heated to 50°C and reacted for 1 hour, then cooled to room temperature to obtain a first isocyanate group-containing acrylic urethane resin solution. The reaction molar ratio (number of moles of isocyanate groups in the raw materials / number of moles of hydroxyl groups) was 3. The first isocyanate group-containing acrylic urethane resin solution had a theoretical nonvolatile content of 25% by mass and an isocyanate group content of 1.7% by mass as determined by titration.

[0109] [Example 1] While nitrogen gas was flowing into a reaction vessel equipped with a stirrer, a thermometer, a nitrogen seal tube, and a heating / cooling device, 320.0 g of ethyl acetate, 215.0 g of a hydrocarbon solvent (Exxol D110, naphthenic, initial boiling point 248°C, dry point 265°C, manufactured by ExxonMobil Corporation), 135.0 g of the first isocyanate group-containing acrylic urethane resin solution obtained in Synthesis Example 1, and a second isocyanate group-containing acrylic urethane resin solution (SM-4, manufactured by Asia Kogyo Co., Ltd., solids content 59% by mass, 5% by weight of ethylbenzene:xylene) were added. A 0:50 mixed solvent, 150.0 g of an isocyanate group-containing acrylic urethane resin having an isocyanate pendant on the acrylic main chain, NCO content of 3.2 mass%, number average molecular weight of 1,195, weight average molecular weight of 14,638, and 180.0 g of CE-10BE (10 mass% polyethylene particles having an average particle size of 3 to 4 μm, 60 mass% butyl acetate, 30 mass% ethyl acetate, manufactured by Koyo Chemical Co., Ltd.) as a matting agent was added, and the mixture was stirred at room temperature for 1 hour to prepare a surface coating agent composition of a curable composition.

[0110] [Example 2] A surface coating composition of a curable composition was prepared in the same manner as in Example 1, except that 375.0 g of ethyl acetate and 160.0 g of the hydrocarbon solvent were used.

[0111] [Comparative Example 1] A surface coating agent composition of a curable composition was prepared in the same manner as in Example 1, except that the first isocyanate group-containing acrylic urethane resin solution was not used.

[0112] Comparative Example 2 A surface coating agent composition of a curable composition was prepared in the same manner as in Example 1, except that the second isocyanate group-containing acrylic urethane resin solution was not used.

[0113] Comparative Example 3 In the test evaluation, Comparative Example 3 was a case where no surface coating agent composition of a curable composition was used.

[0114] 180 g of the surface coating agent composition of the curable composition of Examples 1 to 2 and Comparative Examples 1 to 2 and 120 g of dimethyl ether were charged into an aerosol can and sealed under pressure. In each evaluation test, a coating amount of about 40 g / m was applied to the surface of the curable composition using the aerosol can. 2 It was spray coated with.

[0115] [Stain prevention (black silica sand stain prevention)] Create a 20mm x 100mm square frame on a slate board using a 10mm thick square backer. A curable composition (Auton Siding Sealant, a one-component moisture-curing polyurethane sealant composition, manufactured by Auto Chemical Industry Co., Ltd.) was poured into the frame, and the surface was smoothed flat with a spatula. Next, the surface coating compositions of Examples 1-2 and Comparative Examples 1-2 were applied to the surface of the curable composition, and the composition was cured for 3 hours under the following temperature and humidity conditions: 5°C, 40% RH, 23°C, 50% RH, and 35°C, 70% RH. After curing, black silica sand (8 Black, manufactured by K-Mu Viewcera) was applied to the surface of the curable composition at a rate of approximately 250 g / m. 2 After sprinkling in an amount of coating, the test specimen was placed upright so that the surface of the curable composition was vertical, and the black silica sand adhering to the surface of the curable composition was brushed off with a No. 5 brush. The state of adhesion of the black silica sand to the surface of the curable composition was visually confirmed and evaluated according to the following criteria. Note that, because the curable composition was in an uncured state, the black silica sand was brushed off slowly with the No. 5 brush so as not to deform the surface of the curable composition. Evaluation criteria ◎: Black silica sand does not adhere to the surface of the curable composition, and the surface of the curable composition is not contaminated ◯: A small amount of black silica sand adheres to the surface of the curable composition, and the surface of the curable composition is slightly contaminated. ×: A large amount of black silica sand adheres to the surface of the curable composition, contaminating the surface of the curable composition.

[0116] [Anti-pollution properties (anti-pollution properties from raindrops)] Two aluminum angles (12 mm wide x 150 mm long x 12 mm deep) were fixed on an aluminum plate in a V-shape (the distance between the aluminum angles was 2 mm at one end and 12 mm at the other end). This was designated as test piece A. A curable composition (Auton Siding Sealant, a one-component moisture-curing polyurethane sealant composition, manufactured by Auto Chemical Industries Co., Ltd.) was poured into the frame of an aluminum channel (width 22 mm × length 150 mm × depth 13 mm), and the surface was smoothed flat with a spatula. The surface of the curable composition was then coated with the surface coating compositions of Examples 1 and 2 and Comparative Examples 1 and 2. This was designated test piece part B. The two parts were fixed so that there was no step between the surface of test specimen part A and the surface of the curable composition of test specimen part B, and so that the end (2 mm side) of the V-shaped part formed by the aluminum angle of test specimen part A touched the midpoint of the long side of the aluminum channel of test specimen part B, and the test specimen part was placed vertically outdoors with the aluminum angle part facing up. Three months after installation, the adhesion of sand and dust to the surface of the curable composition was visually inspected and evaluated according to the following criteria. Evaluation criteria ◎: Almost no dirt such as sand or dust adheres to the surface of the curable composition ○: A small amount of dirt such as sand and dust is attached to the surface of the curable composition. ×: A lot of dirt such as sand and dust adheres to the surface of the curable composition, damaging the appearance.

[0117] [Masking tape peelability] Two sheets of siding (Neolock Hikaricera 18, manufactured by Kemi Corporation) were attached parallel to a slate board, creating a joint measuring 10 mm wide x 100 mm long x 10 mm deep. Masking tape was applied to the surface of the siding along the joint edge, and then a curable composition (Auton Siding Sealant, a one-component moisture-curing polyurethane sealant composition manufactured by Auto Chemical Industries Co., Ltd.) was poured into the joint and the surface was smoothed flat with a spatula. Next, the surface coating compositions of Examples 1-2 and Comparative Examples 1-2 were applied to the surface of the curable composition and the masking tape, and the resulting mixture was cured for 10 minutes at a temperature and humidity of 35°C and 70% RH. After curing, the masking tape was peeled off the siding, and visual observation was performed to determine whether stringiness or burrs were present due to the cured coating film of the surface coating composition. Evaluation was based on the following criteria. Evaluation criteria ○: No stringing or burrs due to the cured coating, and the joints and edges are clean △: The hardened coating film causes some stringiness and burrs, and some burrs remain at the joint edges, but the joints are clean. ×: Stringiness and burrs are generated by the cured coating, and the joints and joint edges are visible due to the cured coating.

[0118] [Matte finish] A 20mm x 70mm square frame was created on a slate board using a 10mm thick corner backer, and a curable composition (Auton Siding Sealant, a one-component moisture-curing polyurethane sealant composition, manufactured by Auto Chemical Industry Co., Ltd.) was poured into the frame, and the surface was smoothed flat with a spatula. Next, the surface coating compositions of Examples 1-2 and Comparative Examples 1-2 were applied to the surface of the curable composition, and the composition was cured for 7 days under temperature and humidity conditions of 23°C and 50% RH. The gloss state of the surface of the curable composition was visually confirmed and evaluated according to the following criteria. Evaluation criteria ○: The gloss has disappeared ×: The gloss has not faded

[0119] [Stretchability (dynamic exposure)] A dynamic exposure tester with the following specifications was installed outdoors facing south and used for the test. One piece of siding (Excellage Hydrophilic 14, manufactured by Kemi Corporation) was fixed to each of the fixed and movable jigs of the tester, facing each other, so that the movement of the tester was transmitted to the joints made by the siding. After installing 10 mm thick corner backers into the joints, a one-component urethane primer composition (OP-2020, manufactured by Auto Chemical Industry Co., Ltd.) was applied to the joint-covered surface of the siding and allowed to dry and harden. A curable composition (Auton Siding Sealant, a one-component moisture-curing polyurethane sealant composition, manufactured by Auto Chemical Industry Co., Ltd.) was poured into the joints, and the surface was smoothed with a spatula. The surface of the curable composition was immediately coated with the surface coating compositions of Examples 1-2 and Comparative Examples 1-2. The appearance of the curable composition was visually observed 24 hours after application and evaluated according to the following criteria. The maximum displacement within 24 hours after application was 1.0 mm. Dynamic Exposure Tester Specifications Mounting angle: 30 degrees Movement generating unit: Black acrylic resin plate (length 2,000mm x width 500mm x thickness 40mm) Fixed and movable beams: Aluminum (length 500mm x width 50mm x thickness 50mm) Measuring instruments: Expansion detector, temperature detector Recording device: dot recorder Evaluation criteria 〇: No wrinkles or cracks are found in the joints △: Wrinkles are observed in the joints, but no cracks are observed ×: Wrinkles and cracks are observed in the joints

[0120] [Elasticity (repeated stretch)] Two pieces of siding (Excellage Hydrophilic 14, manufactured by Kemi Corporation) and corner backing were placed on a slate board to create a 10 mm wide x 50 mm long x 10 mm deep joint. A one-component urethane primer composition (OP-2020, manufactured by Auto Chemical Industry Co., Ltd.) was applied to the joint-covered surfaces of the siding and allowed to dry and harden. After that, a curable composition (Auton Siding Sealant, a one-component moisture-curing polyurethane sealant composition, manufactured by Auto Chemical Industry Co., Ltd.) was poured into the joint and smoothed flat with a spatula. Next, the surface coating compositions of Examples 1-2 and Comparative Examples 1-2 were applied to the surface of the curable composition and cured for 14 days at a temperature and humidity of 23°C and 50% RH, followed by another 14 days at a temperature of 30°C. These specimens were used as test specimens. The test specimen was immediately placed in a repeating test machine (special type sealant fatigue test machine, manufactured by Toyo Seiki Co., Ltd.), and the test machine was set so that the displacement width was ±20% (±2 mm) of the joint width, and the expansion and contraction cycle was performed 2,000 times. After 2,000 cycles, the joint surface was visually inspected for wrinkles and cracks and evaluated according to the following criteria. Evaluation criteria 〇: No wrinkles or cracks are found on the joint surface ×: Wrinkles or cracks are observed on the joint surface.

[0121] [Topcoat paint adhesion] A 50mm x 50mm square frame was made on a slate board using a 10mm thick corner backer, and a curable composition (Auton Siding Sealant, a one-component moisture-curing polyurethane sealant composition, manufactured by Auto Chemical Industry Co., Ltd.) was poured into the frame, and the surface was smoothed flat with a spatula. Next, the surface coating compositions of Examples 1-2 and Comparative Examples 1-2 were applied to the surface of the curable composition, and after curing for 3 days under temperature and humidity conditions of 23°C and 50% RH, water-based paint A (primer: water-based Mylacealer Eco (manufactured by SK Chemical Co., Ltd.) at approximately 120g / m2) was applied to the surface of the curable composition. 2Allow to cure for 3 hours after application. Top coat: Water-based Ceramic Silicone (SK Chemical Co., Ltd.) approx. 280g / m 2 Application), or water-based paint B (primer: Hybrid Sealer EPO (SK Chemical Co., Ltd.) approx. 150 g / m 2 Allow to cure for 3 hours after application. Top coat: Water-based Ceramic Silicone (SK Chemical Co., Ltd.) approx. 280g / m 2 The top coat (coating) was applied and cured for 7 days at a temperature and humidity of 23°C and 50% RH. After curing, a grid pattern (25 squares) was cut into the top coat (coating film) with a cutter, and cellophane tape was applied to the surface of the top coat (coating film). After peeling off the cellophane tape, the number of squares (maximum 25 squares) of top coat (coating film) remaining on the sealant was visually confirmed.

[0122] The compositions and evaluation results of the surface coating compositions of Examples 1 and 2 and Comparative Examples 1 and 2 are shown in Table 1 below.

[0123] [Table 1]

[0124] From the results in Table 1 above, it was found that the surface coating compositions of Examples 1 and 2 were excellent in stain resistance (black silica sand stain resistance, raindrop stain resistance), matte finish, and stretchability (dynamic exposure, repeated stretching), and also had excellent masking tape peelability and topcoat paint adhesion.

[0125] On the other hand, in Comparative Example 1, which did not use (A) the first isocyanate group-containing (meth)acrylic urethane resin, stain prevention properties (black silica sand stain prevention properties) were not obtained. Also, in Comparative Example 2, which did not use (B) the second isocyanate group-containing (meth)acrylic urethane resin, stain prevention properties (black silica sand stain prevention properties) were not obtained when aged under temperature and humidity conditions of 5°C, 40% RH and 23°C, 50% RH. Furthermore, in Comparative Example 1, masking tape peelability was not obtained, and in Comparative Example 2, raindrop stain prevention properties and stretchability (dynamic exposure) were not obtained. In Comparative Example 3, in which no curable surface coating composition was used, stain prevention properties (black silica sand stain prevention properties, raindrop stain prevention properties) and matte properties were not obtained. [Industrial Applicability]

[0126] The surface coating agent composition of the curable composition of the present invention has excellent stretchability and can impart excellent stain resistance and matte properties to the surface of the curable composition, and can be suitably used for construction and civil engineering purposes.

Claims

1. (A) a first isocyanate group-containing (meth)acrylic urethane resin, (B) a second isocyanate group-containing (meth)acrylic urethane resin, and (C) an organic solvent; the (A) first isocyanate group-containing (meth)acrylic urethane resin is a reaction product of an organic isocyanate compound including a modified organic polyisocyanate and an active hydrogen-containing compound including an isocyanate group-reactive functional group-containing (meth)acrylic resin, A surface coating agent composition of a curable composition, characterized in that the (B) second isocyanate group-containing (meth)acrylic urethane resin is a reaction product of an organic isocyanate compound not containing a modified organic polyisocyanate and an active hydrogen-containing compound including an isocyanate group-reactive functional group-containing (meth)acrylic resin.

2. 2. The surface coating agent composition of claim 1, wherein the modified organic polyisocyanate has one or more bonds selected from the group consisting of a uretdione bond, an isocyanurate bond, an allophanate bond, a biuret bond, a uretonimine bond, a carbodiimide bond, a urethane bond, and a urea bond.

3. The surface coating agent composition of the curable composition according to claim 1, characterized in that the (B) second isocyanate group-containing (meth)acrylic urethane resin is a resin in which an organic isocyanate compound that does not contain a modified organic polyisocyanate is pendant on an active hydrogen-containing compound that includes an isocyanate group-reactive functional group-containing (meth)acrylic resin.

4. The isocyanate group-reactive functional group is selected from the group consisting of —COOH, —OH, and —NH ２ 2. The surface coating agent composition of claim 1, wherein the functional group is one or more selected from the group consisting of —NH and —SH.

5. The surface coating agent composition of the curable composition according to claim 1, characterized in that the blending ratio of the (A) first isocyanate group-containing (meth)acrylic urethane resin and the (B) second isocyanate group-containing (meth)acrylic urethane resin is 10 / 90 to 90 / 10, in terms of the number of moles of isocyanate groups in the (B) second isocyanate group-containing (meth)acrylic urethane resin relative to the number of moles of isocyanate groups in the (A) first isocyanate group-containing (meth)acrylic urethane resin.

6. The surface coating agent composition of the curable composition according to claim 1, characterized in that the total amount of the (A) first isocyanate group-containing (meth)acrylic urethane resin and the (B) second isocyanate group-containing (meth)acrylic urethane resin is 1 to 70 mass % in the surface coating agent composition.

7. The surface coating agent composition of the curable composition according to claim 1, characterized in that the (C) organic solvent contains 5 to 70 mass % of a hydrocarbon organic solvent having a boiling point (initial boiling point) of 150°C or higher.

8. The surface coating composition of the curable composition according to claim 1, further comprising a matting agent.

9. The surface coating composition of a curable composition according to claim 8, wherein the matting agent is one or more matting agents selected from the group consisting of polyolefins, oxidized polyolefins, and silica.

10. (A) a first isocyanate group-containing (meth)acrylic urethane resin, (B) a second isocyanate group-containing (meth)acrylic urethane resin, and (C) an organic solvent, wherein the (A) first isocyanate group-containing (meth)acrylic urethane resin is an organic polyisocyanate. a surface coating composition, wherein the (B) second isocyanate group-containing (meth)acrylic urethane resin is a reaction product of an organic isocyanate compound not containing a modified organic polyisocyanate and an active hydrogen-containing compound containing a (meth)acrylic resin containing an isocyanate group-reactive functional group, and ...

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