Paint composition set

Abstract

To provide a paint composition set capable of forming a road surface sign coating excellent in adhesion with an asphalt paving that is a coated film, and excellent in durability.SOLUTION: The paint composition set disclosed herein is a paint composition set used to form a multilayer coating having a first coating film and a second coating film. The paint composition set includes a first paint composition for forming the first coating film and a second paint composition for forming the second coating film. The first paint composition is a one-component paint composition containing an isocyanate-terminated urethane prepolymer. The isocyanate-terminated urethane prepolymer includes a diphenylmethane diisocyanate-based urethane prepolymer. The second paint composition is a two-component paint composition including a solvent-free base composition and a solvent-free curing agent composition.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a set of paint compositions. [Background technology]

[0002] Pavement marking coating films are subject to deterioration and wear due to vehicle traffic, etc., and therefore require periodic maintenance such as repainting and repair using a paint composition that forms the pavement marking coating film.

[0003] Patent Document 1 describes a coating composition for forming a coating film for road markings, which is a urethane waterproofing structure consisting of a primer layer applied to a substrate, a waterproofing layer formed on the primer, and a topcoat layer applied to the waterproofing layer.The document describes that the primer layer is formed from a moisture-curing urethane primer material containing 20 to 85% by weight of a solvent whose main component is a non-aromatic solvent, the waterproofing layer is formed from a urethane-based waterproof coating material that does not contain toluene or xylene, and the topcoat layer is formed from a two-component acrylic urethane coating material containing 30 to 80% by weight of a solvent whose main component is a non-aromatic solvent.

[0004] Patent Document 2 describes a primer for asphalt-based substrates, which comprises 30 to 60% by weight of a solvent consisting of one or both of acetone and methyl ethyl ketone, and 70 to 40% by weight of a prepolymer having a viscosity of 20 to 100 poise / 20°C and an isocyanate group content of 5 to 25% by weight, which prepolymer is obtained by reacting some of the isocyanate groups of diphenylmethane diisocyanate with a polyol.

[0005] Patent Document 3 describes a one-component moisture-curing polyurethane surface preparation composition in which 40 to 150 parts by weight of hydraulic cement is added to 100 parts by weight of a urethane prepolymer solution having an isocyanate functional group weight fraction (hereinafter referred to as free isocyanate group content) of 2.5 to 15% by weight relative to the total urethane prepolymer solution.

[0006] Patent Document 4 describes a coating composition comprising a solvent-based composition and a solventless curing agent composition, in which the solventless base composition comprises a film-forming resin, a pigment, and an organometallic catalyst, the film-forming resin comprising at least one selected from the group consisting of a polyol and an aromatic polyfunctional amine, the pigment comprising at least one selected from the group consisting of carbonates, titanium oxide, zinc oxide, precipitated barium sulfate, talc, silica, and kaolin, the solventless curing agent composition comprising at least one selected from the group consisting of an aliphatic polyfunctional isocyanate compound and an aromatic polyfunctional isocyanate compound, and a coating film comprising the coating composition in which the ratio (L / D) of the surface distance (L) of the pigment-dispersed particles to the average particle diameter (D) of the pigment-dispersed particles is 0.4 or more and 2.0 or less. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-299103 [Patent Document 2] Japanese Patent Application Publication No. 53-134036 [Patent Document 3] Japanese Patent Application Publication No. 7-277857 [Patent Document 4] Japanese Patent Application Publication No. 2019-218486 Summary of the Invention [Problem to be solved by the invention]

[0008] Even when a coating film is formed from the materials described in the above patent documents, there are problems with the durability of the coating film, i.e., the durability (abrasion resistance) of the coating film itself, and even if the durability of the coating film itself is good, there are problems such as insufficient adhesion to the asphalt pavement to be coated.

[0009] The present disclosure has been made in view of the above circumstances, and aims to provide a paint composition set that is capable of forming a road marking coating film that has good adhesion to the asphalt pavement that is the substrate and good durability. [Means for solving the problem]

[0010] The present disclosure provides the following aspects. [1] A coating composition set used to form a multi-layer coating film having a first coating film and a second coating film, the coating composition set includes a first coating composition that forms the first coating film and a second coating composition that forms the second coating film, the first coating composition is a one-component coating composition containing an isocyanate group-terminated urethane prepolymer, The isocyanate group-terminated urethane prepolymer includes a diphenylmethane diisocyanate-based urethane prepolymer, The coating composition set, wherein the second coating composition is a two-component coating composition comprising a solvent-free base composition and a solvent-free curing agent composition. [2] The coating composition set according to [1], wherein the first coating composition further contains an organic solvent, and the organic solvent contains an aromatic hydrocarbon solvent. [3] The paint composition set according to [1] or [2], wherein the content of the aromatic hydrocarbon solvent is 70 mass% or more relative to 100 mass% of the total amount of organic solvents contained in the first paint composition. [4] The solvent-free base composition comprises a film-forming resin, a pigment, and an organometallic catalyst; the film-forming resin comprises at least one selected from the group consisting of polyols and aromatic polyfunctional amines; the pigment comprises at least one selected from the group consisting of calcium carbonate, titanium oxide, zinc oxide, precipitated barium sulfate, talc, silica, and kaolin; The volume average particle diameter of the pigment is 0.2 μm or more and 50 μm or less, The solventless curing agent composition contains at least one compound selected from the group consisting of an aliphatic polyfunctional isocyanate compound and an aromatic polyfunctional isocyanate compound, The paint composition set according to any one of [1] to [3], wherein the amount of the pigment is 5 parts by mass or more and 55 parts by mass or less per 100 parts by mass of the solid content of the second paint composition. [5] The coating composition set according to any one of [1] to [4], wherein the ratio [NCO / (OH+NH2)] of the equivalent of isocyanate groups contained in the solvent-free curing agent composition to the sum of the equivalent of hydroxyl groups and the equivalent of amino groups contained in the solvent-free base composition is 0.5 or more and 2.0 or less. [6] The paint composition set according to [4] or [5], wherein the content of the pigment is 5 parts by mass or more and 55 parts by mass or less per 100 parts by mass of the solid content of the second paint composition. [7] The paint composition set according to any one of [1] to [6], which is for road markings and / or road heat insulation. [8] A method for producing a multi-layer coating film, a first coating step of coating a first coating composition on an object to be coated to form a first coating film; a second coating step in which a second coating composition is applied onto the first coating film immediately after the first coating composition is applied to the substrate and before the first coating film is cured and dried, thereby forming a laminated coating film in which the first coating film and the second coating film are laminated; and A curing step of curing the laminated coating film to form a multi-layer coating film, the first coating composition comprises an isocyanate group-terminated urethane prepolymer; The isocyanate group-terminated urethane prepolymer includes a diphenylmethane diisocyanate-based urethane prepolymer, A method for producing a multilayer coating film, wherein the second coating composition is a two-component coating composition comprising a solvent-free base composition and a solvent-free curing agent composition. [9] [8] A method for producing a multilayer coating film, wherein in the second coating step, a second coating composition is applied onto the first coating film after the first coating film has become dry to the touch but before it has hardened and dried, to form a laminated coating film in which the first coating film and the second coating film are laminated. [Effects of the Invention]

[0011] According to the present disclosure, it is possible to provide a paint composition set that is capable of forming a road marking coating film that has good adhesion to the asphalt pavement that is the substrate and good durability. DETAILED DESCRIPTION OF THE INVENTION

[0012] The coating composition set of the present disclosure is a coating composition set used to form a multi-layer coating film having a first coating film and a second coating film, the coating composition set includes a first coating composition that forms the first coating film and a second coating composition that forms the second coating film, the first coating composition is a one-component coating composition containing an isocyanate group-terminated urethane prepolymer, The isocyanate group-terminated urethane prepolymer includes a diphenylmethane diisocyanate-based urethane prepolymer, The second coating composition is a two-component coating composition comprising a solvent-free base composition and a solvent-free curing agent composition.

[0013] According to the present disclosure, a paint composition set can be provided that can form a road marking coating film that has good adhesion to the substrate, i.e., asphalt pavement. While the present disclosure should not be interpreted as being limited to a particular theory, the reason why the paint composition set of the present disclosure can achieve such effects is thought to be as follows. Specifically, by first applying a first paint composition, the first paint composition penetrates into the substrate, hardens, and strengthens the substrate. Furthermore, the moisture-curable polyisocyanate compound contained in the first paint composition and the film-forming component contained in the second paint composition form chemical bonds, which at least partially integrate these components to form a strong coating film. As a result, it is thought that adhesion between the substrate, i.e., asphalt pavement, and the coating film formed by the paint composition set is improved.

[0014] (First paint composition) The first coating composition is a one-component coating composition containing a diphenylmethane diisocyanate-based urethane prepolymer. This first coating composition has good affinity with the second coating composition, and can form a composite coating film with excellent adhesion to the substrate via chemical bonding. In the present disclosure, a one-component coating composition refers to a composition that can form a coating film using only the components contained in the one-component coating composition, without using a curing agent, crosslinking agent, or the like.

[0015] In this disclosure, a urethane prepolymer refers to a polymer compound obtained by reacting a polyol with a polyisocyanate in an amount such that the number of isocyanate groups is in excess relative to the hydroxyl groups contained in the polyol, and refers to a compound having isocyanate groups at the molecular terminals that can be cured by moisture in the air. The urethane prepolymer may typically be a reaction product of a polyol and a low-molecular-weight polyisocyanate.

[0016] The polyol is a compound having two or more hydroxy groups in one molecule, and examples thereof include low-molecular-weight polyols and polymer polyols. Examples of the low-molecular-weight polyols include aliphatic polyols such as ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,4-pentanediol, neopentyl glycol, 1,5-hexanediol, and 1,6-hexanediol; alicyclic polyols such as hydrogenated bisphenol A and 1,4-cyclohexanedimethanol; bisphenol A; and bisphenol B. Examples of the polyols include aromatic polyols such as phenol A and hydroxyalkylated bisphenol A (particularly, bisphenol hydroxypropyl ether); polyols having a carboxy group such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2-dimethylolbutyric acid, and 2,2-dimethylolvaleric acid; and tri- or higher functional polyols such as glycerin, mannitol, trimethylolethane, trimethylolpropane, trimethylolbutane, hexanetriol, pentaerythritol, and dipentaerythritol.

[0017] Examples of the polymer polyol include polyether polyol, acrylic polyol, polyurethane polyol, polyester polyol, polyesteramide polyol, etc. (for example, polyols having a weight-average molecular weight of 800 or more), and polyether polyol is preferred. The polyether polyol may be a polyether polyol obtained by addition polymerization of one or more alkylene oxides selected from ethylene oxide, propylene oxide, etc. to one or more initiators selected from water, ethylene glycol, propylene glycol, etc.

[0018] Examples of the polyisocyanate include aliphatic polyisocyanates such as hexamethylene diisocyanate; alicyclic polyisocyanates such as 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and hydrogenated xylylene diisocyanate; and aromatic polyisocyanates such as tolylene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, metaphenylene diisocyanate, polymethylene polyphenyl diisocyanate, naphthylene diisocyanate, and 3,3'-dimethyl-4,4'-biphenylene diisocyanate.

[0019] The isocyanate group content of the isocyanate group-terminated urethane prepolymer is preferably 1.0% by mass or more and 25.0% by mass or less, more preferably 2.0% by mass or more and 20% by mass or less, and even more preferably 8.0% by mass or more and 17.0% by mass or less. When the isocyanate group content is within the above range, the resulting coating film can have good adhesion to the substrate.

[0020] The number average molecular weight of the isocyanate group-terminated urethane prepolymer may be preferably from 100 to 10,000, more preferably from 500 to 8,000, and even more preferably from 1,000 to 5,000. When the number average molecular weight is within the above range, the resulting coating film can have good adhesion to the substrate.

[0021] The urethane prepolymer includes a diphenylmethane diisocyanate-based urethane prepolymer (hereinafter also referred to as an "MDI-based urethane prepolymer"). The diphenylmethane diisocyanate-based urethane prepolymer may be a reaction product of a polyol and diphenylmethane diisocyanate, preferably a reaction product of a polymer polyol and 4,4-diphenylmethane diisocyanate, and more preferably a reaction product of a polyether polyol and 4,4-diphenylmethane diisocyanate.

[0022] The isocyanate group content of the MDI-based urethane prepolymer is preferably 1.0% by mass or more and 25.0% by mass or less, more preferably 2.0% by mass or more and 20% by mass or less, and even more preferably 8.0% by mass or more and 17.0% by mass or less. When the isocyanate group content is within the above range, the resulting coating film can have good adhesion to the substrate.

[0023] The number average molecular weight of the MDI-based urethane prepolymer may be preferably from 100 to 10,000, more preferably from 500 to 8,000, and even more preferably from 1,000 to 5,000. When the number average molecular weight is within the above range, the resulting coating film can have good adhesion to the substrate. In the present disclosure, the number average molecular weight can be measured by gel permeation chromatography as a polystyrene equivalent value.

[0024] The content of the MDI-based urethane prepolymer may be preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and even more preferably 95% by mass or more and 100% by mass or less, based on 100% by mass of the total amount of the isocyanate group-terminated urethane prepolymer.

[0025] In the first coating composition, the content of the isocyanate group-terminated urethane prepolymer is preferably 1% by mass or more and 100% by mass or less, more preferably 1% by mass or more and 80% by mass or less, even more preferably 5% by mass or more and 60% by mass or less, and even more preferably 10% by mass or more and 30% by mass or less. By being within this range, the viscosity of the first coating composition can be adjusted to a viscosity suitable for coating, and an amount of coating sufficient to form a coating film with good adhesion to the substrate can be ensured in one coating, which means that so-called coating workability can be improved.

[0026] The first coating composition preferably further contains an organic solvent, such as aromatic hydrocarbon solvents like xylene and toluene; ketone solvents like acetone, methyl ethyl ketone, and methyl isobutyl ketone; ester solvents like ethyl acetate, propyl acetate, butyl acetate, methyl octenoate, ethyl 3-ethoxypropionate, 3-methoxybutyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and 3-methoxy-3-methylbutyl acetate; ether solvents like dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether, 2-methoxypropanol (propylene glycol monomethyl ether), diethylene glycol monobutyl ether, butyl diglycol, 2-butoxypropanol, tetrahydrofuran, and dioxane; ether acetate solvents like methyl ether acetate, ethylene glycol monoethyl ether acetate, and propylene glycol monomethyl ether acetate; and aliphatic hydrocarbon solvents like methylcyclohexane, ethylcyclohexane, and dimethylcyclohexane.

[0027] In particular, the organic solvent preferably contains an aromatic hydrocarbon solvent such as xylene or toluene. The inclusion of an aromatic hydrocarbon solvent makes it easier to dissolve the asphalt components in the asphalt pavement, which is the substrate, and facilitates penetration and diffusion of the first coating composition into the substrate. The content of the aromatic hydrocarbon solvent, based on 100% by mass of the total amount of the solvent, is preferably 30% by mass to 100% by mass, more preferably 50% by mass to 100% by mass, even more preferably 70% by mass to 100% by mass, even more preferably 75% by mass to 100% by mass, and particularly preferably 80% by mass to 100% by mass. Being within the above range can improve the adhesion of the resulting coating film to the substrate.

[0028] The organic solvent preferably includes an organic solvent with a high evaporation rate. In the present disclosure, "an organic solvent with a high evaporation rate" refers to an organic solvent with a relative evaporation rate of 50 or more, where the evaporation rate of n-butyl acetate is set to 100. The relative evaporation rate is preferably 50 or more, more preferably 60 or more, and even more preferably 70 or more. Examples of the organic solvent include xylene, toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, and butyl acetate. The inclusion of the organic solvent can improve the drying properties of the first coating film obtained by applying the first coating composition, and can improve the durability of the resulting multi-layer coating film.

[0029] The content of the organic solvent with a high relative evaporation rate is preferably 70% by mass or more and 100% by mass or less, more preferably 75% by mass or more and 100% by mass or less, and even more preferably 80% by mass or more and 100% by mass or less, based on 100% by mass of the total amount of the organic solvents. When the relative evaporation rate is within the above range, the drying properties of the first coating film obtained by applying the first coating composition can be good, and the durability of the resulting multilayer coating film can be good.

[0030] The content of the organic solvent is preferably 0.25 to 100 parts by mass, more preferably 0.5 to 50 parts by mass, even more preferably 1 to 10 parts by mass, and even more preferably 1 to 5 parts by mass, relative to 1 part by mass of the urethane prepolymer. When the content is within the above range, coating workability can be improved.

[0031] The total content of the polyisocyanate group-containing urethane prepolymer and solvent is preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and even more preferably 95% by mass or more and 100% by mass or less, based on 100% by mass of the total amount of the first coating composition.

[0032] The isocyanate group content in the first coating composition is preferably 0.01% by mass or more and 25.0% by mass or less, more preferably 0.02% by mass or more and 16.0% by mass or less, and even more preferably 0.4% by mass or more and 10.2% by mass or less. The higher the isocyanate group content in the first coating composition, the more easily the curing reaction of the moisture-curable polyisocyanate compound and the resulting coating film formation proceed. On the other hand, the lower the isocyanate group content in the first coating composition, the easier it is to control the reaction between isocyanate groups and to suppress foaming during application and the resulting decrease in adhesion. In the present disclosure, an isocyanate group refers to an isocyanate group that can be moisture-cured or react with a polyol, etc. The isocyanate group content in the first coating composition can be measured in accordance with the provisions of JIS K 1603-1.

[0033] In addition to the above components, the first coating composition may contain other components such as pigments, resin particles, resin components, dispersants, curing catalysts, viscosity agents, film-forming aids, and additives commonly used in coating compositions (e.g., ultraviolet absorbers, light stabilizers, antioxidants, antifoaming agents, surface conditioners, pinhole prevention agents, rust inhibitors, etc.).

[0034] In the first coating composition, the solid content may be preferably 1% by mass or more and 100% by mass or less, more preferably 10% by mass or more and 80% by mass or less, even more preferably 10% by mass or more and 60% by mass or less, and even more preferably 10% by mass or more and 40% by mass or less. In this disclosure, the solid content of a certain component means the heating residue as defined in JIS K 5601-1-2:2008, and the solid content concentration is calculated by measuring the percentage of the mass of the residue after heating at 105°C for 60 minutes to the original mass.

[0035] (Second paint composition) The second coating composition is a solvent-free type and contains a base agent and a curing agent. Because the second coating composition is solvent-free and suppresses the emission of volatile components, no odor is generated during storage or application, reducing the burden on the environment. Furthermore, the second coating composition has better weather resistance than coating compositions containing large amounts of solvents, such as aqueous solvents and organic solvents, and is capable of forming a coating film with high toughness, making it suitable as a coating composition for forming markings, coatings, etc. on pavements such as road surfaces.

[0036] (solvent-free base) The base resin comprises a film-forming resin (a).

[0037] The film-forming resin (a) is not particularly limited as long as it is a resin having two or more reactive groups in the molecule that can react with the curing agent (b) described below, and is preferably a resin having two or more groups in the molecule that can react with the curing agent (b) described below to form a urethane bond and / or a urea bond. Examples of reactive groups that can react with the curing agent (b) (preferably groups that can react with the curing agent (b) to form a urethane bond and / or a urea bond) that can react with the curing agent (b) include groups that have an active hydrogen atom.

[0038] Examples of the group having an active hydrogen atom include a hydroxyl group, a substituted or unsubstituted amino group, a silanol group, an active methylene group, a thiol group, a carboxyl group, etc. Examples of the coating film-forming resin (a) include polyols and polyamines.

[0039] The polyol may be any compound having two or more hydroxyl groups in the molecule. Specific examples include high-molecular-weight polyols such as polyether polyols, polyester polyols, acrylic polyols, castor oil-based polyols, and polycarbonate polyols; and low-molecular-weight polyols. The number-average molecular weight of the polyol may be, for example, 50 or more, or even 3,000 or more, and may be, for example, 10,000 or less, or even 3,000 or less. The number-average molecular weight of the high-molecular-weight polyol may be, for example, 300 or more, preferably 400 or more, more preferably 700 or more, and may be, for example, 10,000 or less, or even 5,000 or less, particularly 3,000 or less, and particularly 1,000 or less. The molecular weight of the low-molecular-weight polyol may be, for example, less than 700, or even less than 400, particularly 300 or less, or may be 50 or more. In the present disclosure, the number-average molecular weight is expressed as a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0040] The hydroxyl value of the polyol is preferably 50 mgKOH / g or more, and preferably 2,000 mgKOH / g or less, more preferably 1,500 mgKOH / g or less, even more preferably 500 mgKOH / g or less, and even more preferably 350 mgKOH / g or less. When the hydroxyl value of the polyol is in the above range, a coating film having excellent strength is easily obtained. In the present disclosure, the hydroxyl value refers to the hydroxyl value of the solid content, and can be measured in accordance with the provisions of JIS K 0070.

[0041] The number of hydroxyl groups contained in the polyol is 2 or more, preferably 6 or less, more preferably 4 or less, and further preferably 3 or less per molecule.

[0042] The polyether polyol refers to a polyol having a plurality of ether bonds in the molecule, and examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polyoxyethylene polyoxypropylene glycol, polyoxytetramethylene glycol, polyoxyhexamethylene glycol, and polyoxyoctamethylene glycol.

[0043] The polyester polyol refers to a polyol having a plurality of polyester bonds in the molecule. Examples of the polyester polyol include an esterification reaction product of a low-molecular-weight polyol with a polycarboxylic acid, a ring-opening condensation product of a cyclic ester compound, and a copolymer thereof.

[0044] The low-molecular-weight polyol used in producing the polyester polyol is, for example, a polyol having a molecular weight of less than 500. Specific examples include linear or branched aliphatic polyols having 1 to 8 carbon atoms, such as ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 3-methylpentane-1,5-diol, and diethylene glycol; polyols containing an alicyclic structure, such as cyclohexanedimethanol; and aromatic polyols, such as bisphenol A and bisphenol F.

[0045] Examples of polycarboxylic acids used in the production of the polyester polyol include aliphatic polycarboxylic acids such as succinic acid, adipic acid, sebacic acid, and dodecanedicarboxylic acid; aromatic polycarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid; and anhydrides of the aliphatic polycarboxylic acids and aromatic polycarboxylic acids. Among these, aliphatic polycarboxylic acids are preferred, and adipic acid is more preferred.

[0046] Examples of the cyclic ester compound used in the production of the polyester polyol include ε-caprolactone and 3-methylvalerolactone.

[0047] The acrylic polyol refers to a polyol having units derived from a radically polymerizable monomer. Examples of the radically polymerizable monomer include (meth)acrylic acid; (meth)acrylic acid esters of methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate; (meth)acrylic monomers having a hydroxyl group such as 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate; and aromatic monomers such as styrene and α-methylstyrene. The radically polymerizable monomer includes at least a (meth)acrylic monomer having a hydroxyl group. In this disclosure, (meth)acrylic acid refers to acrylic acid and methacrylic acid.

[0048] The acrylic polyol can be produced by polymerizing the radical polymerizable monomer in the absence of a solvent or in the presence of an organic solvent. The polymerization temperature may be 80 to 140° C., and the polymerization time may be 1 to 8 hours.

[0049] The polymerization initiator is not particularly limited, and examples thereof include organic peroxides such as benzoyl peroxide, t-butyl peroxide, and cumene hydroperoxide; and organic azo compounds such as azobiscyanovaleric acid and azoisobutyronitrile.

[0050] The organic solvent that can be used in producing the acrylic polyol is preferably a solvent having a boiling point of 60 to 250°C. Specific examples include water-insoluble organic solvents such as butyl acetate, xylene, toluene, methyl isobutyl ketone, propylene glycol, dipropylene glycol dimethyl ether, and methyl ether acetate; and water-soluble organic solvents such as tetrahydrofuran, ethanol, methanol, propanol, isopropanol, 2-butanol, t-butyl alcohol, dioxane, methyl ethyl ketone, ethylene glycol, ethylene glycol monobutyl ether, 2-methoxypropanol, 2-butoxypropanol, diethylene glycol monobutyl ether, butyl diglycol, N-methylpyrrolidone, ethylene carbonate, and propylene carbonate.

[0051] The castor oil-based polyols include castor oil and its derivatives, specifically monoglycerides and diglycerides of castor oil fatty acids, and mixtures thereof. By including a castor oil-based polyol in the film-forming resin (a), the viscosity of the base resin can be reduced, making it easier to thoroughly mix the base resin with the curing agent.

[0052] Examples of low molecular weight polyols for the coating film-forming resin (a) include ethylene glycol, propylene glycol, butane glycol, hexanediol, methylpentanediol, neopentyl glycol, polyethylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerin, pentaerythritol, dipentaerythritol, sorbitol, inositol, mannitol, glucose, and fructose.

[0053] The polyol preferably contains a castor oil-based polyol, and the content of the castor oil-based polyol in the polyol is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 85% by mass or more, for example, 100% by mass or less.

[0054] The content of the polyol in the coating film-forming resin (a) is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, and is preferably 98% by mass or less, more preferably 96% by mass or less, even more preferably 95% by mass or less.

[0055] The polyamine may be any compound having two or more amino groups in the molecule, and examples thereof include aromatic polyamines in which two or more amino groups are substituted on the aromatic ring of an aromatic hydrocarbon compound; aliphatic polyamines in which two or more amino groups are substituted on an aliphatic hydrocarbon compound; and alicyclic polyamines in which two or more amino groups are substituted on an alicyclic hydrocarbon compound, with aromatic polyamines being preferred.

[0056] In the present disclosure, the aromatic hydrocarbon compound in the aromatic polyamine includes compounds consisting of only an aromatic ring; compounds in which a substituent such as an alkyl group, an alkoxy group, an alkylthio group, or a halogen atom is bonded to an aromatic ring; and compounds in which two or more aromatic rings are bonded to a linking group such as an alkylene group, an oxygen atom, or -CO-. The number of carbon atoms in the alkyl group, alkoxy group, or alkylthio group as the substituent is, for example, 1 to 10, preferably 1 to 5, and the number of carbon atoms in the alkylene group as the linking group is, for example, 1 to 10, preferably 1 to 5. The alkyl group, alkoxy group, alkylthio group, and alkylene group may be linear or branched. Examples of the halogen atom as the substituent include a chlorine atom.

[0057] Examples of the aromatic polyamines include diaminotoluenes (e.g., 2,4-diaminotoluene, 2,6-diaminotoluene, 3,4-diaminotoluene, phenylenediamine, etc.), diethyldiaminotoluenes (e.g., 1-methyl-3,5-diethyl-2,4-diaminobenzene, 1-methyl-3,5-diethyl-2,6-diaminobenzene, 2,4-diethyl-6-methyl-1,3-diaminobenzene, etc. DETDA), 4,4'-diamino-3,3'-dichlorodiphenylmethane, 4,4 Aromatic compounds such as 1,3,5-diamino-3,3'-diethyl-5,5'-dimethylphenylmethane (MEDDM), 1,3,5-triethyl-2,6-diaminobenzene, 4,4'-diaminodiphenylmethane, 3,5,3',5'-tetraethyl-4,4'-diaminodiphenylmethane, 3,5-dimethylthio-2,4-toluenediamine, 3,5-dimethylthio-2,6-toluenediamine, bisaminophenylfluorene, diaminodiphenyl ether, diaminonaphthalene, and diaminobenzophenone. Aromatic diamines: aromatic triamines such as triaminobenzene (1,3,5-triaminobenzene, 1,2,4-triaminobenzene), etc.

[0058] Commercially available aromatic polyamines may be used. Examples of commercially available aromatic polyamines include diaminodiphenylmethane-based amines (Iharacuramine MT, Curehard-MED, both manufactured by Kumiai Chemical Co., Ltd.), phenylenediamine-based amines (Ethacure 100, manufactured by Albemare Corporation), bisaminophenylfluorene-based amines (BAFL, manufactured by JFE Chemical Corporation), diaminodiphenyl ether-based amines (4,4'-diaminodiphenyl ether, manufactured by JFE Chemical Corporation), diaminonaphthalene-based aromatic polyfunctional amines, and diaminobenzophenone-based aromatic polyfunctional amines.

[0059] The content of the aromatic polyamine in the polyamine is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 85% by mass or more, and is, for example, 100% by mass or less.

[0060] The number of amino groups contained in the polyamine is 2 or more, preferably 6 or less, more preferably 4 or less, and further preferably 3 or less per molecule.

[0061] The amine value of the polyamine may be preferably 100 mgKOH / g or more, more preferably 200 mgKOH / g or more, and may be 1,200 mgKOH / g or less, more preferably 800 mgKOH / g or less. Having the amine value of the polyamine within this range facilitates the formation of a tough coating film and facilitates shortening of the curing time. Furthermore, the pot life of the second coating composition can be adjusted, improving workability during application. In the present disclosure, the amine value refers to the solid content amine value, and can be measured in accordance with the provisions of JIS K 7237.

[0062] The content of the polyamine is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less, relative to 100 parts by mass of the polyol.

[0063] The film-forming resin (a) preferably contains a polyol and a polyamine, and the total content of the polyol and the polyamine in the film-forming resin (a) is preferably 80% by mass or more, more preferably 90% by mass or more, and preferably 100% by mass or less.

[0064] In one embodiment, the film-forming resin (a) may include an epoxy resin, a urethane resin, or a urea resin.

[0065] The base material may further contain a pigment. Examples of the pigment include inorganic pigments and organic pigments. The pigment may be in the form of solid particles or hollow particles.

[0066] Examples of the inorganic pigments include calcium carbonate, titanium oxide, zinc oxide, precipitated barium sulfate, talc, silica, zirconia, alumina silicate, zirconia silicate, kaolin, bentonite, smectite, glass flakes (silica fillers), iron oxide, acicular titanium oxide, anthraquinone, bismuth vanadate, carbon black, composite oxide pigments, seashell chalk, eggshell calcium, etc. Examples of the organic pigments include quinophthalone pigments, benzimidazolone pigments, isoindoline pigments, isoindolineone pigments, dioxazine pigments, phthalocyanine pigments (copper phthalocyanine pigments, chlorinated copper phthalocyanine, brominated copper phthalocyanine, etc.), indanthrene pigments, perylene pigments, diketopyrrolopyrrole pigments, azo pigments, azomethine azo pigments, quinacridone pigments, aniline pigments, etc.

[0067] In one embodiment, the pigment may contain an extender pigment. The extender pigment may contain, for example, at least one selected from the group consisting of calcium carbonate, titanium oxide, zinc oxide, precipitated barium sulfate, talc, silica, zirconia, alumina silicate, zirconia silicate, kaolin, seashell chalk, and eggshell calcium. Preferably, the extender pigment contains at least one selected from the group consisting of calcium carbonate, titanium oxide, zinc oxide, precipitated barium sulfate, talc, silica, and kaolin. More preferably, the extender pigment contains at least one selected from the group consisting of calcium carbonate, titanium oxide, and talc. By containing such a pigment, a coating film formed using the second coating composition of the present disclosure can exhibit a white color and can be used to form white lines, etc.

[0068] The pigment may contain a heat-shielding pigment. When the second coating composition of the present disclosure contains a heat-shielding pigment, the resulting coating film has high solar reflectance and can exhibit heat-shielding properties, making it effective in combating the heat island effect. The second coating composition can also be classified as a solar reflectance coating for roofs as specified in JIS K 5675.

[0069] In the present disclosure, a heat-shielding pigment refers to a pigment that does not absorb light in the near-infrared wavelength region (wavelengths of 780 nm to 2,500 nm) or has low absorptance of light in the near-infrared wavelength region (wavelengths of 780 nm to 2,500 nm). The absorptance of light in the near-infrared wavelength region can be evaluated, for example, by solar absorptance in accordance with JIS R 3106. The solar absorptance of the heat-shielding pigment may be, for example, 60% or less, and may vary depending on the color of the heat-shielding pigment; for example, it may be 30% or less for yellow or red heat-shielding pigments, and 15% or less for white heat-shielding pigments.

[0070] The heat-shielding pigment may be a white heat-shielding pigment, a red heat-shielding pigment, a blue heat-shielding pigment, a yellow heat-shielding pigment, a black heat-shielding pigment, etc. The black heat-shielding pigment may be a pigment toned by mixing at least one selected from chromatic heat-shielding pigments such as a red heat-shielding pigment, a blue heat-shielding pigment, and a yellow heat-shielding pigment with an optional pigment other than the heat-shielding pigment.

[0071] The white heat-shielding pigment may be titanium oxide, and an example of a commercially available product thereof is Typec CR-97 (manufactured by Ishihara Sangyo Kaisha).

[0072] Commercially available examples of the red heat-shielding pigment include Fastogen Super Magenta RH (manufactured by DIC Corporation), Fastogen Super Red 7100Y (manufactured by DIC Corporation), Rubicron Red 400RG (manufactured by Tosoh Corporation), and Pacific Red 2020 (manufactured by BASF). These may be used alone or in combination of two or more.

[0073] Commercially available examples of the blue heat-shielding pigment include Dipyroxide Blue #9453 (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), Fastogen Blue 5485K (manufactured by DIC Corporation), Fastogen Blue RSKE (manufactured by DIC Corporation), Cyanine Blue 5240KB (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), and Lionol Blue SPG-8 (manufactured by Toyocolor Co., Ltd.) These may be used alone or in combination of two or more.

[0074] Examples of commercially available yellow heat-shielding pigments include Symuler Fast Yellow 4192 (manufactured by DIC Corporation), Syco Pearl Yellow L-1110 (manufactured by BASF), and Irgacolor Yellow 2GLMA (manufactured by BASF). These may be used alone or in combination of two or more.

[0075] Examples of the black heat-shielding pigment include azomethine azo pigments, perylene pigments, aniline pigments, and calcined composite oxide pigments. These may be used alone or in combination of two or more.

[0076] The heat-shielding pigments are only examples, and the pigments exemplified above may also function as heat-shielding pigments. In such cases, these "pigments" may be used as heat-shielding pigments.

[0077] One or more of the pigments can be used. When two or more pigments are used, the pigments may be mixed in advance before preparing the main and second coating compositions, or a primary color main or primary color second coating composition containing only each pigment may be prepared, and then each primary color main or primary color second coating composition may be mixed.

[0078] In one embodiment, the pigment according to the present disclosure may be spherical, approximately spherical, granular, or the like, and is spherical or approximately spherical to maintain coating strength. Being spherical or approximately spherical can impart higher durability. Furthermore, a coating composition suitable for coating conditions required depending on the substrate, coating conditions, etc. can be appropriately prepared, thereby improving work efficiency. Furthermore, as long as it does not deviate from the scope of the present disclosure, the coating composition may contain a pigment having a spherical, approximately spherical, granular, or other shape and a flat pigment, or may contain only a flat pigment.

[0079] The average particle size (D50) of the pigment is the average particle size (D50) of dispersed particles of the pigment, and is preferably 50 μm or less, more preferably 35 μm or less, and may be, for example, 0.2 μm or more, or even 3 μm or more. The average particle size (D50) of the pigment can be measured using a particle size measuring device such as a laser diffraction / scattering particle size distribution measuring device (Microtrac MT3300EX II, manufactured by Microtrac-Bell). In the present disclosure, D50 is the particle size at which the total volume of particles, accumulated from the smallest particle size to a certain particle size in the particle size distribution, is 50% when expressed as a percentage of the total volume of the particles.

[0080] The content of the pigment is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, even more preferably 12 parts by mass or more, and preferably 55 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 30 parts by mass or less, per 100 parts by mass of the solids content of the second coating composition. By having the pigment content within this range, the viscosity of the base agent becomes appropriate, the mixability of the base agent and the curing agent is good, and the reaction between the film-forming resin and the curing agent is not inhibited, resulting in the formation of a coating film with excellent strength. Furthermore, the tinting power of the second coating composition also becomes good.

[0081] The second coating composition may contain a filler (particles composed of the same material as general pigments but with a larger particle size than general pigments). Examples of such particles include ceramic beads such as SiO2, Al2O3, ZrO2, 3Al2O3·2SiO2, and zirconia silicate, as well as glass beads. The average particle size (D50) of the filler is preferably 500 μm or less, more preferably 200 μm or less, and preferably greater than 50 μm, more preferably 60 μm or more. The shape of the filler may be particulate, spherical, hollow spherical, fibrous, or granular.

[0082] The base agent may further contain an organometallic catalyst. By including a metal catalyst, it is easy to adjust the reactivity of the coating composition, even when the reactivity between the base agent and the curing agent is low. Furthermore, it is possible to suppress the reaction between the curing agent and water, thereby suppressing foaming in the second coating composition. Furthermore, it is possible to improve workability during coating.

[0083] The organometallic catalyst may be any catalyst capable of contributing to the reaction between the base resin and the curing agent. In one embodiment, the organometallic catalyst may be an ester compound of tin, lead, bismuth, zinc, titanium, or the like. Specific examples include dibutyltin dilaurate, bismuth tris(2-ethylhexanoate), lead octoate, and bismuth octoate. Tin esters and / or bismuth esters are preferred as the organometallic catalyst.

[0084] The content of the organometallic catalyst may be, for example, 0.0 to 2% by mass in the solid content of the base agent, from the viewpoint of the reactivity between the base agent and the curing agent.

[0085] The base agent may further contain a dehydrating agent, which can further suppress the generation of carbon dioxide due to the reaction between the moisture adhering to the coated object and the curing agent described below, thereby suppressing unevenness and porosity on the resulting coating film.

[0086] The dehydrating agent is not particularly limited, and examples thereof include synthetic zeolite molecular sieves, calcium sulfate, calcium oxide, and the like.

[0087] The content of the dehydrating agent may be, for example, 0.3 parts by mass or more and 5 parts by mass or less per 100 parts by mass of the solid content of the coating composition, from the viewpoint of sufficiently dehydrating the water that may be contained in the coating composition and suppressing foaming.

[0088] The base material may further contain additives such as aggregates, antifoaming agents, leveling agents, anti-sagging agents, surface conditioners, viscosity adjusters, dispersants, light stabilizers, antioxidants, ultraviolet absorbers, and waxes.

[0089] The base resin can be prepared by mixing the film-forming resin (a) with, as needed, a pigment, an organometallic catalyst, a dehydrating agent, additives, etc. A mixer such as a roll mill, a paint shaker, a pot mill, a disperser, or a sand grind mill may be used for the mixing.

[0090] (solvent-free hardener) The curing agent contains a compound (curing agent (b)) having two or more groups in the molecule that can react with the reactive groups (preferably groups having active hydrogen atoms) of the film-forming resin (a). Examples of groups that can react with the reactive groups of the film-forming resin (a) include isocyanate groups, and the curing agent preferably contains a polyisocyanate.

[0091] Examples of the polyisocyanate include aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; alicyclic diisocyanates such as cyclohexane diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, methylcyclohexane diisocyanate and isophorone diisocyanate; aromatic diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate; and polymers (biuret, isocyanurate, allophanate, adduct) of the aliphatic diisocyanates, alicyclic diisocyanates and aromatic diisocyanates. The polyisocyanates also include modified polyisocyanates in which some of the isocyanate groups have been modified with polyol or the like.

[0092] The polyisocyanates may be used alone or in combination of two or more kinds.

[0093] In one embodiment, the polyisocyanate preferably contains an aliphatic polyisocyanate or an alicyclic polyisocyanate, more preferably an aliphatic polyisocyanate, and even more preferably hexamethylene diisocyanate or a hexamethylene diisocyanate polymer. This can improve the weather resistance of the coating film and suppress discoloration. The total content of the aliphatic polyisocyanate and the alicyclic polyisocyanate in the polyisocyanate is preferably 90% by mass or more, more preferably 95% by mass or more, and preferably 100% by mass or less.

[0094] The content of the polyisocyanate in the curing agent is preferably 90% by mass or more, more preferably 95% by mass or more, and preferably 100% by mass or less.

[0095] The curing agent may further contain the additives and the like.

[0096] The ratio of the isocyanate group equivalents contained in the second coating composition to the sum of the hydroxyl group equivalents and amino group equivalents contained in the solventless base composition [NCO / (OH+NH2)] is preferably 0.5 to 2.0, more preferably 0.7 to 1.7, even more preferably 0.8 to 1.6, and even more preferably 0.8 to 1.55. By keeping this ratio within this range, the coating film can be sufficiently cured to obtain a tougher coating film, which can have excellent abrasion resistance and durability.

[0097] (Method of manufacturing multi-layer coating film) The method for producing a multilayer coating film according to the present disclosure includes: A step of applying the first coating composition to an object to be coated to form a first coating film (first coating film forming step); A step of applying a second coating composition onto the first coating film immediately after the first coating composition is applied to the substrate and before the first coating film is cured and dried, thereby forming a laminated coating film in which the first coating film and the second coating film are laminated (second coating film forming step); and A step of curing the laminated coating film to form a multi-layer coating film (multi-layer coating film forming step), the first coating composition comprises an isocyanate-terminated urethane prepolymer; The isocyanate group-terminated urethane prepolymer and the diphenylmethane diisocyanate-based urethane prepolymer are included, The second coating composition is a two-component coating composition comprising a solvent-free base composition and a solvent-free curing agent composition.

[0098] According to the manufacturing method of the present disclosure, it is possible to form a road marking coating film that has good adhesion to the asphalt pavement that is the substrate.

[0099] (First painting process) In the first coating film forming step, the first coating composition is applied to an object to be coated to form a first coating film, thereby forming a base layer containing a polyisocyanate compound.

[0100] The coating method is not particularly limited, and at least one method selected from the group consisting of spray coating, roller coating, flow coating, and a combination of two or more of these methods can be used.

[0101] Examples of substrates to which the first coating composition is applied include pavements such as road surfaces. The type of pavement is not particularly limited, and examples include asphalt pavement and concrete pavement. The asphalt used in the asphalt pavement is not particularly limited, and examples include dense-graded asphalt mixtures, fine-graded asphalt mixtures, dense-graded gap asphalt mixtures, open-graded asphalt mixtures, and porous asphalt mixtures. The surface of the substrate may be smooth like a concrete pavement surface, or may have irregularities like an asphalt pavement surface.

[0102] The amount of the first coating composition applied is 25 g / m when applied to a smooth surface. 2 More than 300g / m 2The amount of the first coating composition applied can be adjusted within the following range: 2 More than 50g / m 2 or more, for example 300 g / m 2 or less, preferably 200 g / m 2 The amount may be as follows:

[0103] The method for drying the first coating film is not particularly limited, and may be, for example, drying at room temperature (ambient temperature), or forced drying using an infrared heater, burner, etc., depending on the ambient environment, such as the air temperature and the temperature of the substrate. In one embodiment, the coating composition may be applied while being heated or kept at a temperature of 10°C to 80°C, or the coating composition immediately after application may be heated or kept at a temperature of 10°C to 80°C. Setting the temperature within this range makes it possible to form a coating film that has good adhesion to the substrate and a multi-layer coating film with a long service life.

[0104] The first coating film may be formed by one coating operation, or may be formed by two or more coating operations.

[0105] (Second painting process) Next, a second coating composition is applied onto the first coating film immediately after the first coating composition is applied to the substrate and before the first coating film hardens and dries, thereby forming a laminated coating film consisting of the first and second coating films. By applying the second coating composition within this time period, a coating film with excellent adhesion to the asphalt pavement, which is the substrate, and a long service life can be formed. That is, the time immediately after the first coating composition is applied is defined as t0, and the time required from t0 until the coating film formed by applying the first coating composition reaches a cured and dried state is defined as t H When the time from t0 to the start of application of the second coating composition is t2, The time t H and t2 is t0 <t2<t H (Formula 1) The relationship may be:

[0106] In this disclosure, the term "hardened and dried state" refers to the hardened and dried state specified in JIS K 5600-1-1, and specifically means "a state in which, when the center of the coating surface is firmly pinched between the thumb and index finger, no fingerprint indentation is left on the coating surface, no movement of the coating film is felt, and when the center of the coating surface is rapidly and repeatedly rubbed with the fingertips, no scratches are left on the coating surface."

[0107] In one embodiment, it is preferable to apply the first coating composition to a substrate, and then, after the first coating film has become dry to the touch but before it has hardened and dried, apply the second coating composition onto the first coating film to form a laminated coating film in which the first and second coating films are laminated. By applying the second coating composition within this time period, a coating film with excellent adhesion to the asphalt pavement, which is the substrate, and a long service life can be formed.

[0108] That is, the time immediately after the first coating composition is applied is defined as t0, and the time required from t0 until the coating film formed by applying the first coating composition becomes dry to the touch is defined as t F Then, The time t F , t H and t S but, t F <t2<t H (Formula 2) The relationship may be:

[0109] In this disclosure, "dry to the touch" refers to the dry state defined in JIS K 5600-1-1, and specifically means "the state in which the fingertip does not get dirty when lightly touching the center of the coating surface with the fingertip."

[0110] The base agent and curing agent in the second coating composition may be mixed before or simultaneously with coating. When the base agent and curing agent are mixed before coating, they are preferably mixed immediately before coating.

[0111] The coating method is not particularly limited, and at least one method selected from the group consisting of spray coating, coating using a static method, coating using a collision mix method, slit coater coating, flow coating, and a combination of two or more of these methods can be used, and in particular at least one method selected from the group consisting of coating using a collision mix method, spray coating, slit coater coating, flow coating, and a combination of two or more of these methods can be used.

[0112] When using a coating method such as spray coating, slit coater coating, static coating, or flow coating, the base agent and curing agent may be mixed before coating. When using a coating method such as spray coating or collision mixing coating, the base agent and curing agent may be mixed during coating.

[0113] In one embodiment, the coating method of the present disclosure may include two-liquid impingement mixing spray coating, in which two liquid components, a base resin and a curing agent, are sprayed by collision mixing. Two-liquid impingement mixing spray coating can be performed, for example, by spraying the base resin and the curing agent under high pressure and then causing collision mixing at the coating location. For two-liquid impingement mixing spray coating, it is preferable to use a high-pressure two-liquid impingement mixing type spraying device.

[0114] The amount of the second coating composition to be applied can be adjusted so that the film thickness after drying and curing when applied to a smooth surface is 50 μm or more and 2,000 μm or less. The second coating composition may be applied multiple times as needed. The amount of the second coating composition to be applied when applied to a smooth surface is, for example, 100 g / m 2 or more, preferably 300 g / m 2 More preferably, 350 g / m 2 For example, the amount may be 2,000 g / m or more. 2 or less, preferably 1,000 g / m² or less, more preferably 600 g / m² or less 2 The amount may be as follows:

[0115] In one embodiment, the coating composition may be applied while being heated or kept at a temperature of 10°C to 60°C, or the coating composition immediately after application may be heated or kept at a temperature of 10°C to 60°C. Setting the temperature within this range makes it easy to reduce or suppress the gloss of the resulting coating film. Furthermore, coating films can be formed on substrates with various surface morphologies, and coating films with excellent abrasion resistance and long service life can be formed. Furthermore, the coating film formation time can be further shortened compared to conventional coating film production methods.

[0116] (hardening process) In the curing step, the multilayer coating film is cured to form a multilayer coating film. The first coating film can be moisture-cured, and the second coating film can undergo a curing reaction between the base resin and the curing agent without any modification. Therefore, the method for drying the multilayer coating film is not particularly limited, and may be, for example, drying at room temperature or forced drying using an infrared heater, burner, etc., depending on the ambient environment, such as the air temperature and the temperature of the coated object.

[0117] (Aggregate spreading process) The method for producing a multi-layer coating film of the present disclosure may include a step of scattering aggregate on the surface of the second coating film (aggregate scattering step) after the second coating film forming step and before the curing step.

[0118] By including the aggregate scattering step, the resulting coating film can be imparted with anti-slip properties.

[0119] As the aggregate, artificial aggregates produced using one or more materials selected from glass flakes, glass beads, expanded shale, fly ash, coal ash, clay, expanded slate, ready-mixed concrete sludge, paper sludge, waste foundry sand, perlite, fireproof stone, and obsidian as the main raw material; natural aggregates such as volcanic gravel, etc. can be used as appropriate.

[0120] The particle size distribution of the aggregate can be selected appropriately, and it may be coarse aggregate containing particles that can pass through a sieve with 5 mm openings at 85% or more by mass, or fine aggregate containing particles that can pass through a sieve with 10 mm openings at 100% by mass and particles that can pass through a sieve with 5 mm openings at 85% or more by mass.

[0121] The aggregate may be dispersed alone, or a dispersion liquid may be prepared by dispersing the aggregate with a dispersion resin and a dispersion medium, if necessary, and then dispersed. The dispersion resin may be an acrylic resin, a polyester resin, a urethane resin, or the like, and the dispersion medium may be water or a hydrophilic solvent, as described below, as appropriate.

[0122] The method for scattering the aggregate is not particularly limited, and any method used in the relevant field can be used as appropriate.

[0123] The amount of the aggregate to be scattered is not particularly limited, and can be adjusted as appropriate within a range in which at least a portion of the second paint film is exposed.

[0124] The coating composition set and method for producing a multilayer coating film of the present disclosure can form a multilayer coating film that has good adhesion to the substrate, and therefore the present disclosure can be suitably applied to coating compositions and methods for producing multilayer coating films for forming markings, coatings, etc. on pavements such as road surfaces. [Example]

[0125] The present invention will be explained in more detail with reference to the following examples, but the present invention is not limited to these examples.

[0126] (Method for preparing first coating composition) The components contained in the first coating composition are as follows: Isocyanate-terminated urethane prepolymer : Urethane prepolymer 11: Desmodur E XP 2762 (manufactured by Sumika Covestro, MDI-based urethane prepolymer); NCO group content: 13.0 to 15.5% by mass, solids concentration: 100% by mass Urethane prepolymer 12: Sumidur E21-1 (manufactured by Sumika Covestro, MDI-based urethane prepolymer); NCO group content: 15.5 to 16.5% by mass, solids concentration: 100% by mass Polyisocyanate compounds: Polyisocyanate compound 13: Sumidur L-75 (manufactured by Sumika Covestro, TDI-based polyisocyanate); NCO group content: 12.5 to 13.5% by mass, solids concentration: 75% by mass (ethyl acetate: 25% by mass) Polyisocyanate compound 14: Millionate MR-100 (Tosoh Corporation, MDI-based polyisocyanate); NCO group content: 30.5 to 32.0 mass%, solid content: 100 mass% organic solvents : Organic solvent 1: Toluene (Shoei Chemical Co., Ltd., aromatic hydrocarbon solvent) Organic solvent 2: Xylol (Shoei Chemical Co., Ltd., xylene: aromatic hydrocarbon solvent) Organic solvent 3: Methyl ethyl ketone (Shoei Chemical Co., Ltd., an aliphatic hydrocarbon solvent) Organic solvent 4: Butyl acetate (Shoei Chemical Co., Ltd., a fatty hydrocarbon solvent)

[0127] The above components were blended in the amounts (parts by mass) shown in Tables 1 to 4 and mixed using a disper to prepare a first coating composition.

[0128] (Method for preparing second coating composition) (Solvent-free base composition) The solvent-free base composition contains the following components: Film-forming resin: Polyol 1: URIC-H368 (Ito Oil Mills, castor oil-based polyol); solid content hydroxyl value: 195 mg KOH / g, number average molecular weight: approximately 700 Polyol 2: URIC-H62 (Ito Oil Mills, castor oil-based polyol); solid content hydroxyl value: 260 mg KOH / g, number average molecular weight: approximately 450 Multifunctional amine 1: Ethacure 100 (Albemarle, DETDA; solid amine value: 629 mg KOH / g) others: Organometallic catalyst: TVS Tin Laur (manufactured by Nitto Kasei Co., Ltd., dibutyltin laurate (DBTL)) Dehydrating agent: Zeolum A4 (Tosoh Corporation, zeolite) Pigment 1: Typaque CR-97 (manufactured by Ishihara Sangyo Kaisha, titanium dioxide) Pigment 2: Super 2000 (Maruo Calcium Co., Ltd., calcium carbonate) Pigment 3: Sunlight SL2200 (Takehara Chemical Industry Co., Ltd., calcium carbonate) Pigment 4: TALCSSS (talc, manufactured by Nippon Talc Co., Ltd.)

[0129] The solvent-free base compositions containing the above ingredients were blended in the amounts (parts by mass) shown in Table 1 and mixed using a disper to prepare solvent-free base compositions.

[0130] (Solvent-free curing agent composition) The solvent-free curing agent composition contains the following components: Solvent-free hardener: Polyisocyanate compound 21: Coronate HXLV (manufactured by Tosoh Corporation, aliphatic isocyanate compound (hexamethylene diisocyanate trimer)); NCO content: 23.2% by mass Polyisocyanate compound 22: Millionate MR-200 (manufactured by Tosoh Corporation, aromatic isocyanate compound (polymeric MDI)); NCO content: 31% by mass

[0131] The solventless base composition and solventless curing agent composition obtained above were blended so that the ratio of the total of the OH group equivalents and NH2 group equivalents contained in the solventless base composition to the NCO group equivalent contained in the solventless curing agent composition [NCO / (OH+NH2)] was the amount shown in Tables 1 to 4, and mixed using a disper to prepare a second coating composition. The second coating composition was prepared immediately before the preparation of the test panel.

[0132] (Examples 1 to 35, Comparative Examples 1 to 4) The first composition shown in Tables 1 to 4 was applied at an amount of 100 g / m2 to an asphalt mixture specimen (300 × 300 mm) and a slate board (100 × 200 mm) coated with an asphalt component at 23°C (outside temperature). 2The coating was sprayed so that the coating was uniform and then cured for 15 minutes to obtain an (uncured) first coating film. After that, at 23°C (outside temperature), the second coating composition was applied on top of the first coating film in an amount of 600 g / m 2 The first and second coating films were then dried and cured to obtain a test plate having a multilayer coating film. The slate boards coated with asphalt components were prepared by spraying asphalt components (open grain type I, manufactured by Green Consultant Co., Ltd.) diluted with toluene onto the slate boards and then curing at 23°C for one day.

[0133] (Measurement of the average particle size (D50) of pigments) The average particle size of the pigment was measured (23° C.) using a laser diffraction particle size distribution analyzer SALD-2200 (Shimadzu Corporation) after adjusting the coating composition with toluene to an appropriate measurement concentration. When the coating composition contains multiple pigment species, the average particle diameter (D) was determined by measuring the average particle diameter (D50) of the pigment mixture, and this value was used as the average particle diameter (D) of the pigments.

[0134] Evaluation items 1) Adhesion (cross-cut test) The coating film of the test board (slate board coated with asphalt component) obtained in the above Examples and Comparative Examples was scored with a cutter at 1 mm intervals, 11 lines vertically and horizontally, and cloth tape (manufactured by Sekisui Co., Ltd.) was applied to the scores and peeled off. The number of remaining squares out of 100 squares was counted to evaluate adhesion (cross-cut test). 100 / 100 indicates that the coating film peeled off 0% of the area. For example, 90 / 100 indicates that the coating film peeled off 10% of the area, and 50 / 100 indicates that the coating film peeled off 50% of the area. The evaluation criteria are as follows: ◎:100 / 100 ○:90 / 100~99 / 100 △:80 / 100~89 / 100 ×: 79 / 100 or less

[0135] 2) Abrasion resistance The abrasion resistance of the coating was evaluated for the test plates (asphalt mixture specimens) obtained in the above Examples and Comparative Examples using a torsion tester (manufactured by Nakajima Gihan Co., Ltd.). Specifically, a tire was brought into contact with the coating surface of the test plate, and while a load was applied to the contact area in a direction perpendicular to the coating surface, the tire was rotated, and the coating peeling rate was calculated using binarization software (GIMP software) to evaluate the coating abrasion resistance. The evaluation criteria were as follows. The coating peeling rate was calculated using the following formula: Paint peeling rate (%) = paint peeling area / tire contact area x 100 Test conditions: tire contact area: 10,000 mm 2 The test was performed at a temperature of 23°C, a load of 490N, a rotation speed of 15 rpm, and a test time of 30 minutes. The tire used was a Hyde Cart air tire with a diameter of 220mm, a width of 65mm, and an air pressure of 2.0 x 100kPa. ◎: Peeling rate is 0%. ○: Peeling rate is more than 0% and less than 10%. △: Peeling rate is 10% or more and less than 20%. ×: Peeling rate is 20% or more.

[0136] [Table 1]

[0137] [Table 2]

[0138] [Table 3]

[0139] [Table 4]

[0140] Examples 1 to 35 are examples of the present invention, and multi-layer coating films were obtained that had good durability (abrasion resistance) and good adhesion to the asphalt pavement that was the substrate.

[0141] Comparative Example 1 is an example in which the first coating film was not used, and the resulting multi-layer coating film was not fully satisfactory in terms of adhesion to the asphalt pavement, which was the substrate, and durability (abrasion resistance). Comparative Example 2 is an example in which no isocyanate-terminated urethane prepolymer was used, and the resulting multilayer coating film was not fully satisfactory in terms of adhesion to the asphalt pavement, which was the substrate, and durability (abrasion resistance). Comparative Examples 3 and 4 are examples in which an isocyanate-terminated urethane prepolymer was not used, but instead a polyisocyanate compound was contained. The resulting multilayer coating film was not uniform, and the adhesion and durability (abrasion resistance) to the asphalt pavement, which was the substrate, were not fully satisfactory. [Industrial Applicability]

[0142] The coating composition set of the present disclosure has good adhesion to the asphalt pavement, which is the substrate, and is capable of forming a coating film that is durable even when subjected to vehicle traffic, etc. Therefore, the coating composition set of the present disclosure can be suitably used for road markings.

Claims

1. A coating composition set used to form a multi-layer coating film having a first coating film and a second coating film, the coating composition set includes a first coating composition that forms the first coating film and a second coating composition that forms the second coating film, the first coating composition is a one-component coating composition containing an isocyanate group-terminated urethane prepolymer, The isocyanate group-terminated urethane prepolymer includes a diphenylmethane diisocyanate-based urethane prepolymer, The coating composition set, wherein the second coating composition is a two-component coating composition comprising a solvent-free base composition and a solvent-free curing agent composition.

2. The coating composition set according to claim 1 , wherein the first coating composition further comprises an organic solvent, and the organic solvent comprises an aromatic hydrocarbon solvent.

3. 2. The paint composition set according to claim 1, wherein the content of the aromatic hydrocarbon solvent is 70 mass% or more relative to 100 mass% of the total amount of organic solvents contained in the first paint composition.

4. The solvent-free base composition comprises a film-forming resin, a pigment, and an organometallic catalyst; the film-forming resin comprises at least one selected from the group consisting of polyols and aromatic polyfunctional amines; the pigment comprises at least one selected from the group consisting of calcium carbonate, titanium oxide, zinc oxide, precipitated barium sulfate, talc, silica, and kaolin; The volume average particle diameter of the pigment is 0.2 μm or more and 50 μm or less, The solventless curing agent composition contains at least one compound selected from the group consisting of an aliphatic polyfunctional isocyanate compound and an aromatic polyfunctional isocyanate compound, The paint composition set according to claim 1 , wherein the amount of the pigment is 5 parts by mass or more and 55 parts by mass or less per 100 parts by mass of the solid content of the second paint composition.

5. The ratio of the equivalent weight of the isocyanate group contained in the solvent-free curing agent composition to the sum of the equivalent weight of the hydroxyl group and the equivalent weight of the amino group contained in the solvent-free base composition [NCO / (OH+NH ２ 2. The coating composition set according to claim 1, wherein the value of [(Ratio of Ratio of Ratio of 1 / Ratio of 2 / R ...1 / Ratio of 1 / Ratio of 1 / Ratio of 1 / Ratio of 1 / Ratio of 1 /

6. The paint composition set according to claim 4, wherein the content of the pigment is 5 parts by mass or more and 55 parts by mass or less per 100 parts by mass of the solid content of the second paint composition.

7. The paint composition set according to any one of claims 1 to 6, which is for road marking and / or road heat insulation.

8. A method for producing a multi-layer coating film, a first coating step of coating a first coating composition on an object to be coated to form a first coating film; a second coating step in which a second coating composition is applied onto the first coating film immediately after the first coating composition is applied to the substrate and before the first coating film is cured and dried, thereby forming a laminated coating film in which the first coating film and the second coating film are laminated; and A curing step of curing the laminated coating film to form a multi-layer coating film, the first coating composition comprises an isocyanate group-terminated urethane prepolymer, the isocyanate group-terminated urethane prepolymer comprises a diphenylmethane diisocyanate-based urethane prepolymer, A method for producing a multilayer coating film, wherein the second coating composition is a two-component coating composition comprising a solvent-free base composition and a solvent-free curing agent composition.

9. 9. The method for producing a multilayer coating film according to claim 8, wherein in the second coating step, a second coating composition is applied onto the first coating film after the first coating film has become dry to the touch but before it has become hardened and dry, thereby forming a laminated coating film in which the first coating film and the second coating film are laminated.

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