Coating formation method

Abstract

To provide a coating forming method for roofing materials that minimizes moisture-related anomalies in the drying process, capable of forming a coating with superior adaptability and weather resistance.SOLUTION: The present invention provides a coating forming method that involves applying a topcoat material to a roofing material. The topcoat material comprises a base agent and a curing agent. The base agent comprises a polyol compound (A). The curing agent comprises a polyisocyanate compound (B) and a silicate compound (C). The polyisocyanate compound (B) comprises a polyisocyanate compound (b1) with an isocyanate group content of less than 14 wt.% and a polyisocyanate compound (b2) with an isocyanate group content of 14 wt.% or more.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a film forming method.

Background Art

[0002] For the purpose of protecting the structures of buildings, civil engineering structures, etc., imparting design properties, and enhancing aesthetics, etc., painting is performed with various coating materials. Among them, roofing materials are easily deteriorated because they are directly affected by severe natural environments such as rainwater and direct sunlight, and weather resistance is required. For example, in Patent Document 1, a coating material composed of a main agent containing acrylic polyol and a curing agent containing isocyanate and a silane coupling agent is described.

[0003] On the other hand, since the painting of roofing materials is generally carried out outdoors, it is affected by the painting environment (temperature, etc.). For example, in the drying process, moisture may adhere to the film due to rainwater or dew condensation. Such adhesion of moisture may cause defects in the film. In addition, roofing materials may expand and contract due to temperature changes, etc., and the film thereon is required to have followability.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a method capable of suppressing defects caused by moisture in the drying process and forming a film excellent in weather resistance and followability.

Means for Solving the Problems

[0006] To solve these problems, the inventors of the present invention, after diligent study, came up with a method for forming a coating by applying a specific topcoat material to a roofing material, and thus completed the present invention.

[0007] In other words, the present invention has the following features. 1. A method for forming a coating by applying a topcoat to a roofing material, The aforementioned topcoat material comprises a main component and a hardening agent. The main component comprises a polyol compound (A), The polyol compound (A) comprises a non-aqueous dispersion resin (a1), The curing agent comprises a polyisocyanate compound (B) and a silicate compound (C). The polyisocyanate compound (B) comprises a polyisocyanate compound (b1) having an isocyanate group content of less than 14% by weight and a polyisocyanate compound (b2) having an isocyanate group content of 14% by weight or more. fruit, The weight ratio of component (b1) to component (b2) [(b1) / (b2)] is 0.6 to 8. A method for forming a coating, characterized by the features described above. 2. The method for forming a film according to 1, characterized in that the polyisocyanate compound (B) contains 20 to 90% by weight of the polyisocyanate compound (b1). 3. The method for forming a coating according to 1. or 2., characterized in that the silicate compound (C) is contained in an amount of 0.1 to 50 parts by weight per 100 parts by weight of the solid content of the polyol compound (A). 4. The method for forming a film according to 1. or 2., characterized in that the polyol compound (A) contains a silicone component. 5. The method for forming a film according to 1, characterized in that the silicate compound (C) is a condensate (c1) of a tetraalkoxysilane containing an alkoxyl group having 1 to 2 carbon atoms and an alkoxyl group having 3 to 12 carbon atoms. [Effects of the Invention]

[0008] According to the coating method of the present invention, when painting roofing materials, problems caused by moisture during the drying process can be suppressed, and a coating with excellent weather resistance and conformability can be formed. [Modes for carrying out the invention]

[0009] The following describes embodiments for carrying out the present invention.

[0010] The present invention relates to a method for forming a coating, which involves applying (painting) a specific topcoat material to a roofing material.

[0011] Roofing materials are components that make up the roof, and examples include metal roofing materials and ceramic roofing materials. Examples of metal roofing materials include iron, cold-rolled steel, aluminum steel, stainless steel, copper steel, hot-dip galvanized steel, hot-dip zinc-aluminum alloy plated steel, electro-galvanized steel, electro-alloy plated steel, alloy plated steel, copper plated steel, tin plated steel, etc., or those that have been surface-treated (for example, surface treatment with phosphate-based treatment agents, chromate-based treatment agents, etc.). Examples of ceramic roofing materials include ceramic tiles, clay tiles, concrete tiles, slate boards, and fiber-reinforced cement boards. Furthermore, the above-mentioned metal roofing materials and ceramic roofing materials may have various existing coatings, such as at least one coating selected from organic coatings, inorganic coatings, organic-inorganic composite coatings, etc.

[0012] The above-mentioned metal roofing materials generally have high thermal conductivity and are prone to condensation, but in the present invention, even when a coating is formed on the metal roofing material, sufficient resistance to moisture such as condensation can be ensured.

[0013] The topcoat material of the present invention comprises a main component and a curing agent, wherein the main component contains a polyol compound (A), and the curing agent contains a polyisocyanate compound (B) and a silicate compound (C).

[0014] Examples of the polyol compound (A) (hereinafter also referred to as the “component (A)”) include polyether polyol, polyester polyol, acrylic polyol, fluorine-containing polyol, etc. In addition, it is also possible to use phenolic resin polyol, epoxy polyol, polybutadiene polyol, polyisoprene polyol, polyester-polyether polyol, urea-dispersed polyol, carbonate polyol, etc. As the component (A), one or more of these can be used, and among them, it is desirable to contain acrylic polyol.

[0015] As the acrylic polyol, a copolymer of an alkyl (meth)acrylate, a hydroxyl group-containing monomer and, if necessary, other monomers can be used. Among these, examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-amyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, octadecyl (meth)acrylate, cyclohexyl (meth)acrylate, etc. Examples of the hydroxyl group-containing monomer include hydroxyalkyl esters of (meth)acrylic acid such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, etc.; hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, hydroxypentyl vinyl ether, etc.; hydroxyallyl ethers such as ethylene glycol monoallyl ether, diethylene glycol monoallyl ether, triethylene glycol monoallyl ether, etc. One or more of these can be used.

[0016] In addition, as other monomers constituting the acrylic polyol, for example, amino group-containing monomers such as dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, dimethylamino (meth) acrylate, aminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate; carboxyl group-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, maleic acid or its monoalkyl ester, itaconic acid or its monoalkyl ester, fumaric acid or its monoalkyl ester; amide-containing monomers such as (meth) acrylamide, ethyl (meth) acrylamide; nitrile group-containing monomers such as (meth) acrylonitrile; epoxy group-containing monomers such as glycidyl (meth) acrylate; aromatic hydrocarbon-based monomers such as styrene, methylstyrene, chlorostyrene, vinyltoluene; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, etc. can be mentioned, and one or more of these can be used as necessary.

[0017] Component (A) preferably further contains a silicone component (hereinafter, the component (A) containing a silicone component is also referred to as a "silicone-containing polyol compound"). By containing a silicone component, an effect of improving long-term weather resistance can be obtained. As such a form of the silicone component, those having a chain shape, a branched shape, a cyclic shape, etc. can be used. The content of the silicone component is preferably 0.1 to 20% by weight (more preferably 0.5 to 10% by weight) in terms of SiO2 in the resin solid content. In the case of the above range, an effect of improving long-term weather resistance can be obtained, and sufficient followability and adhesion to the substrate can be ensured. In the present invention, "α to β" is synonymous with "α or more and β or less".

[0018] In this invention, SiO2 equivalent refers to the weight of silica (SiO2) remaining after a compound containing an Si-O bond is completely hydrolyzed and then calcined at 900°C. Generally, alkoxysilanes, silicates, silicones, etc., react with water to undergo hydrolysis, becoming silanols. Further condensation reactions occur with silanols and with alkoxyls. This reaction, when carried to its ultimate conclusion, results in silica (SiO2). These reactions are... RO(Si(OR)2O)nR + (n+1)H2O → nSiO2 + (2n+2)ROH (R represents an alkyl group. n is an integer.) This is represented by the following reaction equation. In this invention, the SiO2 equivalent is calculated based on this reaction equation, determining the amount of remaining silica component.

[0019] (A) The method for introducing silicone into component is not particularly limited and various methods can be employed, for example, (1) A method for copolymerizing a silicone compound having polymerizable double bonds, (2) A method of reacting a functional group in a resin with a silicone compound having a functional group that can react with the functional group, (3) A method of reacting a reactive silyl group-containing compound with a resin copolymerized with a reactive silyl group-containing monomer, (4) A method in which a functional group in a resin is reacted with a coupling agent having a functional group that can react with the functional group, and then a reactive silyl group-containing compound is reacted.

[0020] Examples of functional group combinations in (2) and (4) above include hydroxyl group and isocyanate group, hydroxyl group and carboxylic acid anhydride group, amino group and isocyanate group, carboxyl group and epoxy group, amino group and epoxy group, and alkoxysilyl groups.

[0021] The reactive silyl groups in (3) and (4) above are those in which an alkoxyl group, phenoxy group, mercapto group, amino group, halogen, etc. are bonded to a silicon atom. As reactive silyl group-containing compounds, those having two or more reactive silyl groups in one molecule are used, for example, tetrafunctional alkoxysilanes such as tetraethoxysilane, tetramethoxysilane, and tetrabutoxysilane; methyltrimethoxysilane, methyltriethoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltributoxysilane, propyltrimethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, and phenyltributoxysilane; dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldibutoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, dipropyldimethoxysilane, dipropyl Examples include difunctional alkoxysilanes such as diethoxysilane, dibutyldimethoxysilane, dibutyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diphenyldibutoxysilane, methylphenyldimethoxysilane, and methylphenyldiethoxysilane; chlorosilanes such as tetrachlorosilane, methyltrichlorosilane, ethyltrichlorosilane, propyltrichlorosilane, phenyltrichlorosilane, vinyltrichlorosilane, dimethyldichlorosilane, diethyldichlorosilane, diphenyldichlorosilane, and methylphenyldichlorosilane; and acetoxysilanes such as tetraacetoxysilane, methyltriacetoxysilane, phenyltriacetoxysilane, dimethyldiacetoxysilane, and diphenyldiacetoxysilane. One or more of these can be used. Compounds having one reactive silyl group in a single molecule can also be used in combination.

[0022] The reactive silyl group-containing monomer in (3) above is a compound containing a reactive silyl group and a polymerizable double bond, and examples include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri-n-butoxysilane, vinyltris(β-methoxyethoxy)silane, allyltrimethoxysilane, trimethoxysilylethyl vinyl ether, triethoxysilylethyl vinyl ether, trimethoxysilylpropyl vinyl ether, triethoxysilylpropyl vinyl ether, γ-(meth)acryloyloxypropyltrimethoxysilane, γ-(meth)acryloyloxypropyltriethoxysilane, γ-(meth)acryloyloxypropylmethyldimethoxysilane, vinylmethyldimethoxysilane, methyldimethoxysilylethyl vinyl ether, methyldimethoxysilylpropyl vinyl ether, etc., and one or more of these can be used.

[0023] The coupling agent in (4) above is, for example, a compound having at least one alkoxysilyl group and other substituents in one molecule. Specific examples of coupling agents include β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, isocyanate-functionalized silane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, and γ-methacryloxypropyltriethoxysilane, and one or more of these can be used.

[0024] In the present invention, it is preferable that component (A) contains the above-mentioned silicone-containing polyol compound in an amount of 50 to 100% by weight (more preferably 50 to 99% by weight, and even more preferably 60 to 95% by weight) on a solid content basis. In this case, it is possible to obtain the effect of excellent film properties such as weather resistance.

[0025] The hydroxyl value (solid content) of component (A) is preferably 5 to 200 KOH mg / g (more preferably 10 to 180 KOH mg / g, and even more preferably 30 to 150 KOH mg / g). When the above range is met, excellent effects can be observed in various coating properties, stain resistance, etc. The hydroxyl value is a value expressed by the number of mg of potassium hydroxide equivalent to the hydroxyl groups contained in 1 g of the sample.

[0026] The glass transition temperature of component (A) is preferably -10 to 80°C (more preferably 0 to 60°C). If the glass transition temperature is within this range, the coating properties such as stain resistance, flexibility, and durability can be improved. The glass transition temperature is a value determined by Fox's formula based on the vinyl monomers constituting the resin.

[0027] Examples of the form of component (A) include a non-aqueous dispersible resin (a1), a soluble resin (a2), etc., and one or more of these can be used. In the present invention, it is preferable to include at least a non-aqueous dispersible resin (a1), and it is even more preferable to use a non-aqueous dispersible resin (a1) and a soluble resin (a2) in combination. Specific examples of component (A) using a combination of a non-aqueous dispersible resin (a1) and a soluble resin (a2) include, • Non-aqueous dispersible polyol compounds and soluble polyol compounds, • Non-aqueous dispersible polyol compounds and soluble silicone-containing polyol compounds, • Non-aqueous dispersion type silicone-containing polyol compound and soluble polyol compound, • Non-aqueous dispersion type silicone-containing polyol compound and soluble silicone-containing polyol compound, Examples include the above. Furthermore, as the polyol compound of the above embodiment, an embodiment containing an acrylic polyol is preferred. This is advantageous in terms of stain resistance, conformability (flexibility), etc.

[0028] In this invention, the non-aqueous dispersion resin (a1) of component (A) refers to a resin in which component (A) is dispersed as resin particles in a non-aqueous solvent. The soluble resin (a2) refers to a resin in which component (A) is dissolved in a non-aqueous solvent.

[0029] The non-aqueous solvent preferably contains an aliphatic hydrocarbon-containing non-aqueous solvent (a so-called weak solvent). Aliphatic hydrocarbon-containing non-aqueous solvents have lower toxicity than toluene, xylene, etc., offer higher safety during operation, and have less impact on air pollution. Examples of aliphatic hydrocarbons include n-hexane, n-pentane, n-octane, n-nonane, n-decane, n-undecane, and n-dodecane. These can be used individually or in combination of two or more. In this invention, aliphatic hydrocarbons can also be introduced by using a mixed solvent such as mineral spirits. The aliphatic hydrocarbon is preferably present in an amount of 5% by weight or more of the total amount of the non-aqueous solvent, and more preferably in an amount of 10 to 80% by weight.

[0030] Non-aqueous solvents may include solvents that are miscible with aliphatic hydrocarbons. Examples of such solvents include petroleum-based solvents such as petroleum ether, petroleum naphtha, and solvent naphtha, as well as ethyl acetate, butyl acetate, methyl ethyl ketone, and methyl isobutyl ketone. Suitable solvents include, for example, petroleum-based solvents (aromatic hydrocarbon-containing petroleum mixed solvents) with a mixed aniline point or aniline point of 12 to 70°C. The mixed aniline point or aniline point is a value measured by the method of JIS K2256:2013.

[0031] Furthermore, when using a combination of a non-aqueous dispersible resin (a1) and a soluble resin (a2) as component (A), it is preferable that the hydroxyl value of the non-aqueous dispersible resin (a1) is greater than that of the soluble resin (a2). In such cases, the crosslinking density of the coating increases, further enhancing weather resistance, conformability, and stain resistance. The mechanism of action is not limited to this, but it is presumed that the soluble resin, which undergoes a somewhat milder crosslinking reaction, crosslinks between the particles of the non-aqueous dispersible resin, resulting in a more uniform distribution of hydroxyl groups in the coating and making it less likely for the crosslinking reaction to be uneven. This leads to the formation of a uniform coating with a high crosslinking density, improving weather resistance, conformability, and stain resistance.

[0032] Specifically, the hydroxyl value of the non-aqueous dispersion resin (a1) is preferably 5 to 200 KOH mg / g (more preferably 10 to 180 KOH mg / g, even more preferably 35 to 160 KOH mg / g, and particularly preferably 40 to 150 KOH mg / g), and the hydroxyl value of the soluble resin (a2) is preferably 5 to 200 KOH mg / g (more preferably 10 to 180 KOH mg / g, even more preferably 30 to 150 KOH mg / g, and even more preferably 35 to 100 KOH mg / g). In such cases, the crosslinking density of the coating is increased, and the above effects can be fully exhibited.

[0033] Furthermore, in the present invention, the difference between the hydroxyl value of the non-aqueous dispersion resin (a1) and the hydroxyl value of the soluble resin (a2) is preferably 1 to 50 KOH mg / g (more preferably 2 to 40 KOH mg / g). In this case, the above effect can be further enhanced.

[0034] Furthermore, the mixed weight ratio [(a1) / (a2)] of the non-aqueous dispersion resin (a1) and the soluble resin (a2) is preferably 99 / 1 to 50 / 50 (more preferably 98 / 2 to 60 / 40). In this case, the above effects can be further enhanced.

[0035] (B) The polyisocyanate compound (hereinafter also referred to as "component (B)") has two or more isocyanate groups in one molecule and reacts with component (A) to form a coating. Component (B) is preferably one that can react and harden with component (A) at room temperature. Here, "room temperature" generally refers to a temperature between -10°C and 50°C, preferably between 5°C and 45°C.

[0036] (B) Component(s) include at least one diisocyanate selected from aliphatic diisocyanates and alicyclic diisocyanates, and alcohol components, and optionally polyol components, which are derivatized by alfanation, biuretation, dimerization (uretidioneation), trimerization (isocyanurateation), adductation, carbodiimideation, etc., and mixtures thereof. These can be used individually or in combination of two or more.

[0037] Aliphatic diisocyanates are compounds that have a saturated aliphatic group in their molecule, such as 1,4-diisocyanatobutane, 1,5-diisocyanatopentane, 1,6-diisocyanatohexane (also known as hexamethylene diisocyanate (HDI)), 1,6-diisocyanato-2,2,4-trimethylhexane, and methyl 2,6-diisocyanatohexanoate (lysine diisocyanate). On the other hand, alicyclic diisocyanates are compounds that have a cyclic aliphatic group in their molecule, such as 5-isocyanato-1-isocyanatomethyl-1,3,3-trimethylcyclohexane (isophorone diisocyanate), 1,3-bis(isocyanatomethyl)cyclohexane (hydrogenated xylylene diisocyanate), bis(4-isocyanatocyclohexyl)methane (hydrogenated diphenylmethane diisocyanate), and 1,4-diisocyanatocyclohexane. Among these, aliphatic diisocyanates (especially HDI) are the most preferred due to their excellent weather resistance and flexibility.

[0038] Examples of alcohol components include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, 1-pentanol, 2-pentanol, isoamyl alcohol, 1-hexanol, 2-hexanol, 1-heptanol, 1-octanol, 2-ethyl-1-hexanol, 3,3,5-trimethyl-1-hexanol, tridecanol, pentadecanol, palmityl alcohol, stearyl alcohol, cyclopentanol, cyclohexanol, methylcyclohexanol, and trimethylcyclohexanol. These can be used individually or in combination of two or more.

[0039] Examples of polyol components include polyether polyols, polyester polyols, and polyolefin polyols. In the present invention, polyether polyols such as polypropylene triol, polypropylene glycol, and polytetramethylene glycol are particularly preferred. These can be used individually or in combination of two or more.

[0040] The present invention is characterized by comprising, as component (B), a polyisocyanate compound (b1) (hereinafter also referred to as "component (b1)") having an isocyanate group content of less than 14% by weight (preferably 2% to 13% by weight) in the solid content, and a polyisocyanate compound (b2) (hereinafter also referred to as "component (b2)") having an isocyanate group content of 14% by weight or more (preferably 15% to 30% by weight, more preferably 16% to 28% by weight). By using components (b1) and (b2) in combination, it is possible to form a coating with excellent curability (especially initial curability), suppresses problems caused by moisture such as condensation during the drying process, and has excellent finish (gloss, etc.), and moreover, it can exhibit excellent weather resistance, stain resistance, etc., so that a good finish can be maintained for a long period of time. In addition, excellent conformability to roofing materials can be obtained. In this invention, the isocyanate group content is defined as the amount of isocyanate groups (by weight) contained in the solid content of the polyisocyanate compound, and is a value obtained by back titration with hydrochloric acid after neutralizing the isocyanate groups with an excess amine.

[0041] In the present invention, it is preferable that component (B) contains 20 to 90% by weight (more preferably 30 to 80% by weight, and even more preferably 45 to 75% by weight) of component (b1). On the other hand, it is preferable that component (B) contains 10 to 80% by weight (more preferably 20 to 70% by weight, and even more preferably 25 to 55% by weight) of component (b2). Furthermore, it is preferable that the weight ratio of component (b1) to component (b2) [(b1) / (b2)] is 0.5 or more (more preferably 0.6 to 8, even more preferably 0.7 to 5, and particularly preferably 1 to 3). In this range, the above effects can be further enhanced.

[0042] The mixing ratio of component (B) should be set considering the molar ratio [NCO] / [OH] between the isocyanate groups of component (B) and the hydroxyl groups of component (A). The molar ratio [NCO] / [OH] between the isocyanate groups of component (B) and the hydroxyl groups of component (A) is preferably 0.6 to 1.4 (more preferably 0.8 to 1.3). Such a ratio can further enhance the effects of the present invention.

[0043] The mixing ratio (weight ratio) of component (A) and component (B) is determined by the hydroxyl value of component (A) and the isocyanate group content of component (B). In the topcoat material of the present invention, the mixing ratio of component (B) is preferably 5 to 50 parts by weight (more preferably 10 to 40 parts by weight) per 100 parts by weight of the resin solids of component (A). If component (B) is within this range, the above NCO / OH molar ratio can be satisfied.

[0044] Silicate compound (C) (hereinafter also referred to as "component (C)") primarily enhances the weather resistance of the formed film and further improves its adhesion. Furthermore, it can impart hydrophilicity to the formed film, which is advantageous in terms of stain resistance.

[0045] Examples of such (C) components include tetraalkoxysilanes, condensates of tetraalkoxysilanes, and modified versions thereof. Examples of tetraalkoxysilanes include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetraisobutoxysilane, tetrasec-butoxysilane, tetrat-butoxysilane, tetraphenoxysilane, monoethoxytrimethoxysilane, monobutoxytrimethoxysilane, monopentoxytrimethoxysilane, monohethoxytrimethoxysilane, dimethoxydiethoxysilane, and dimethoxydibutoxysilane. These can be used individually or in combination of two or more.

[0046] In the present invention, it is preferable to use a condensate (c1) of a tetraalkoxysilane containing an alkoxyl group having 1 to 2 carbon atoms and an alkoxyl group having 3 to 12 carbon atoms (hereinafter referred to as "component (c1)"). In particular, it is preferable that component (c1) is such that 5% to 50% by weight of the total alkoxyl groups of the compound are alkoxyl groups having 3 to 12 carbon atoms.

[0047] Examples of alkoxy groups having 3 to 12 carbon atoms include linear alkoxy groups such as n-propoxy, n-butoxy, n-pentyloxy, n-hexyloxy, n-octyloxy, and n-dodecyloxy groups, and branched alkoxy groups such as isopropoxy, isobutoxy, t-butoxy, sec-butoxy, isopentyloxy, neopentyloxy, isohexyloxy, 3-methylpentyloxy, 1-methylhexyloxy, 1-ethylpentyloxy, 2,3-dimethylbutoxy, 1,5-dimethylhexyloxy, 2-ethylhexyloxy, 1-methylheptyloxy, and t-octyloxy groups.

[0048] Such (c1) components can be produced by known methods. Examples of methods for producing (c1) include modifying a tetraalkoxysilane condensate having alkoxyl groups with 1 to 2 carbon atoms with an alcohol having 3 to 12 carbon atoms.

[0049] The mixing ratio of component (C) is preferably 0.1 to 50 parts by weight (more preferably 0.5 to 40 parts by weight, and even more preferably 2 to 30 parts by weight) per 100 parts by weight of the resin solids of component (A). If component (C) is within this range, excellent weather resistance, adhesion, and stain resistance effects can be obtained.

[0050] Furthermore, the mixing ratio of component (B) and component (C) is preferably 5 to 80 parts by weight (more preferably 10 to 60 parts by weight) of component (C) per 100 parts by weight of solid content of component (B). If component (C) is within this range, excellent weather resistance, adhesion, and stain resistance effects can be obtained.

[0051] The curing agent of the present invention can be manufactured by uniformly stirring and mixing the above components (B) and (C) using conventional methods.

[0052] The topcoat material of the present invention is a two-component coating material consisting of the above-mentioned main component and the above-mentioned hardener, and is used by uniformly stirring and mixing the main component and hardener by conventional methods during application. Furthermore, the topcoat material of the present invention may contain, in addition to the above-mentioned components, various other components in the main component and / or curing agent, to an extent that does not affect the effects of the present invention. Examples of such components include pigments, catalysts, plasticizers, preservatives, fungicides, algaecides, defoamers, leveling agents, coupling agents, pigment dispersants, thickeners, anti-skinning agents, dehydrating agents, matting agents, ultraviolet absorbers, light stabilizers, antioxidants, solvents, and the like. It may also contain resin components other than the above-mentioned component (A).

[0053] In the present invention, it is preferable to include a pigment (hereinafter also referred to as "component (D)"). By including component (D), the color tone, gloss, etc. of the coating can be adjusted. As component (D), (d1) a coloring pigment (hereinafter also referred to as "component (d1)"), (d2) an extender pigment (hereinafter also referred to as "component (d2)"), etc. can be used.

[0054] (d1) The components that can be used include chromatic pigments, white pigments, black pigments, etc. Of these, chromatic pigments are pigments that exhibit chromatic colors such as yellow, orange, red, green, blue, and purple. Examples of such chromatic pigments include inorganic ones such as ferric oxide, hydrated ferric oxide, ultramarine, cobalt blue, and cobalt green, and organic ones such as azo, naphthol, pyrazolone, anthraquinone, perylene, quinacridone, disazo, isoindolinone, benzimidazole, phthalocyanine, and quinophthalone. On the other hand, white pigments are pigments that exhibit white color, and examples include titanium dioxide, zinc oxide, and aluminum oxide. Black pigments are pigments that exhibit a black color, and examples include inorganic substances such as iron black, iron-manganese composite oxide, iron-copper-manganese composite oxide, iron-chromium-cobalt composite oxide, copper-chromium composite oxide, and copper-manganese-chromium composite oxide, as well as carbon black. These can be used individually or in combination of two or more. Furthermore, their surfaces may be treated in some way.

[0055] (d2) Examples of components include heavy calcium carbonate, light calcium carbonate, kaolin, clay, pottery clay, china clay, diatomaceous earth, hydrated fine silica, talc, barite powder, barium sulfate, precipitated barium sulfate, barium carbonate, magnesium carbonate, silica powder, aluminum hydroxide, etc. These can be used individually or in combination of two or more. (d2) components can be used for purposes such as gloss adjustment (gloss reduction, etc.), solid content adjustment, viscosity adjustment, and improvement of storage stability and pigment miscibility.

[0056] The mixing ratio of component (D) is preferably 1 to 300 parts by weight (more preferably 5 to 250 parts by weight) per 100 parts by weight of the solid content of component (A). Also, component (d1) is preferably 1 to 200 parts by weight (more preferably 5 to 150 parts by weight) per 100 parts by weight of the solid content of component (A). When component (d2) is used, component (d2) is preferably 100 parts by weight or less (more preferably 1 to 80 parts by weight) per 100 parts by weight of the solid content of component (A).

[0057] The topcoat material of the present invention can be diluted during application. A non-aqueous solvent containing aliphatic hydrocarbons is preferred as the diluent.

[0058] Various painting methods can be used, such as brush painting, roller painting, and spray painting. The amount of paint applied per coat is preferably 30 to 250 g / m². 2 , comfortably 50~200g / m 2 Furthermore, after the first coat of paint has dried, the next coat (overcoat) can be applied. The drying temperature is preferably -10 to 50°C, more preferably 5 to 45°C. The number of coats is preferably two or more.

[0059] The film formed by the above-mentioned topcoat material may be glossy or matte (including 70% gloss, 50% gloss, 30% gloss, etc.). In this invention, even with a glossy film, problems such as a decrease in gloss caused by moisture such as condensation can be suppressed, and a film with excellent finish (gloss, etc.) can be formed. A glossy film is a film with a specular gloss of 70 or higher (preferably 75 to 90). Furthermore, "specular gloss" is a value measured in accordance with JIS K5600-4-7 "Specular Gloss". Specifically, it is a value obtained by applying the topcoat material to one side of a glass plate using a film applicator with a gap of 150 μm, and measuring the specular gloss (measurement angle 60 degrees) when the coated surface is placed horizontally and dried for 72 hours under standard conditions.

[0060] In the film-forming method of the present invention, various undercoats (e.g., sealers, surfacers, fillers, intermediate coats, etc.) can be applied before applying the topcoat. The topcoat should be applied when the undercoat is dry. One or more types of undercoats can be used.

[0061] Examples of primers include acrylic resin primers, epoxy resin primers, urethane resin primers, and chlorinated rubber primers. Such primers may be clear or colored. They may also contain rust-preventive pigments such as phosphate, molybdate, or zinc.

[0062] Furthermore, various components can be incorporated into the undercoat material to an extent that does not affect the effects of the present invention. Examples of such components include coloring pigments, extender pigments, rust inhibitors, thickeners, film-forming aids, leveling agents, coupling agents, plasticizers, antifreeze agents, pH adjusters, diluents, preservatives, antifungal agents, antialgal agents, antibacterial agents, dispersants, defoaming agents, ultraviolet absorbers, antioxidants, light stabilizers, fibers, catalysts, crosslinking agents, and the like.

[0063] Such primers can be applied using various methods, such as brush painting, roller painting, spray painting, roll coater, and flow coater. The application rate depends on the form of the primer, but is preferably 0.05 to 3 kg / m². 2 (more preferably 0.05~2kg / m 2 ) [Examples]

[0064] The following examples illustrate the features of the present invention. (A) Polyol compounds • (A-1) Silicone-containing acrylic polyol compound dispersion (non-aqueous dispersion resin, solids content: 50% by weight, hydroxyl value (solids content): 55KOH mg / g, silicone component content: 3% by weight (SiO2 equivalent), medium: mineral spirits) • (A-2) Acrylic polyol compound dispersion (non-aqueous dispersion resin, solids content: 50% by weight, hydroxyl value (solids content): 55KOH mg / g, medium: mineral spirits) • (A-3) Acrylic polyol compound solution (soluble resin, solids content: 50% by weight, hydroxyl value (solids content): 55KOH mg / g, medium: mineral spirits) • (A-4) Acrylic polyol compound solution (soluble resin, solids content: 50% by weight, hydroxyl value (solids content): 40KOH mg / g, medium: mineral spirits) (B) Polyisocyanate compounds (B-1) Hexamethylene diisocyanate derivative solution (solid content: 100% by weight, isocyanate group content: 12% by weight) • (B-2) Hexamethylene diisocyanate derivative solution (solid content: 100% by weight, isocyanate group content: 21% by weight) • (B-3) Hexamethylene diisocyanate derivative solution (solid content: 100% by weight, isocyanate group content: 17% by weight) (B-4) Hexamethylene diisocyanate derivative solution (solid content: 100% by weight, isocyanate group content: 14.8% by weight) Note that (B-1) is component (b1), and (B-2) to (B-4) are components (b2). (C) Silicate compound (C-1) Tetramethoxysilane • (C-2) tetramethoxysilane compound modified with i-butyl alcohol (average degree of condensation 4, transesterification rate 30%, silica retention rate 40%) (D) Pigment Rutile-type titanium dioxide (solvent) • Non-aqueous solvents containing aliphatic hydrocarbons: Mineral spirits (Additives) • Antifoaming agents, thickeners, etc.

[0065] (Example 1) • Manufacturing of the main component Main component 1 was prepared by mixing and stirring 60 parts by weight of component (A-1), 25 parts by weight of component (D), 10 parts by weight of solvent, and 5 parts by weight of additive. • Manufacturing of hardeners (B-1) Component 2.8 parts by weight, (B-2) Component 4.4 parts by weight, (C-1) Component 3 parts by weight, and solvent 9.8 parts by weight were mixed and stirred to produce curing agent 1. Preparation of topcoat material Main component 1 (100 parts by weight) and hardener 1 (20 parts by weight) were mixed ([NCO] / [OH]=1.02) and stirred to obtain topcoat material 1.

[0066] (Examples 2-15, Comparative Examples 1-6) Except for the changes in the formulations shown in Tables 1 and 2, the main component and hardener were prepared in the same manner as in Example 1, and these were mixed to obtain the topcoat material.

[0067] The topcoat materials prepared in Examples 1-15 and Comparative Examples 1-6 were evaluated as follows. The results are shown in Tables 1 and 2.

[0068] (Test 1) Using a film applicator, the topcoat was applied to an aluminum plate to a thickness of 150 μm, and the plate was left to dry for 72 hours under standard conditions (temperature 23°C, relative humidity 50%) to prepare test specimen [I]. The 60° specular gloss (hereinafter also simply referred to as "gloss") of the coating on test specimen [I] was measured. The evaluation is as follows. A: Glossiness level 85 or higher B: Glossiness 80 or higher but less than 85 C: Glossiness 75 or higher but less than 80 D: Glossiness less than 75

[0069] (Exam 2) Using a film applicator, the topcoat was applied to an aluminum plate to a thickness of 150 μm. The plate was then left to stand in a 5°C incubator for 2 hours, followed by a 5-minute period under standard conditions (condensation was induced during this cycle). This cycle was repeated a total of three times, followed by 24 hours in the 5°C incubator and 24 hours under standard conditions. The appearance of the coating obtained by the above method was compared with the appearance of test specimen [I]. A rating was given to those with no change in appearance, and a rating of "D" to those with changes (such as a decrease in gloss). (Excellent: A > B > C > D: Poor)

[0070] (Exam 3) For slate roofing materials, the topcoat is spray-painted (0.15 kg / m² per coat). 2 Test specimen [II] was prepared by applying two coats of paint and allowing it to dry and cure for 14 days under standard conditions. In the above-mentioned test specimen [II], after exposure to an accelerated weathering tester (Metal Weather; manufactured by Daipla Wintes Co., Ltd.) for 500 hours, the changes in the appearance of the surface of test specimen [I] (gloss, color, blistering, peeling, and cracking) were observed. The evaluation was performed on a five-point scale (Excellent: AA > A > B > C > D: Poor) by comparing the changes in appearance with the test specimen before exposure. Specimens that showed no change were rated "AA", while those that showed a decrease in gloss, discoloration, blistering, peeling, or cracking were rated "D".

[0071] (Exam 4) Test specimens [II] were prepared by coating a tin plate (150 mm × 50 mm × 0.3 mm) with each coating material to a dry film thickness of 75 μm and drying for 7 days. All coating and drying were carried out under standard conditions. In each test specimen [II], the test plate was bent according to the method of JIS K5600-5-1 "Flexural Resistance" (mandrel diameter: 2 mm), and its surface condition was observed. The evaluation was performed on a five-point scale (Excellent: AA > A > B > C > D: Poor), with "AA" indicating high conformability to the substrate and no cracking, and "D" indicating low conformability to the substrate and cracking.

[0072] (Exam 5) A carbon dispersion (1%) was sprayed onto the test specimen [II] prepared by the method described above, and after drying (60°C, 1 hour), it was washed with water. The difference in brightness (ΔL value) before and after contamination of the test specimen was measured to evaluate the stain resistance test. The ΔL value was measured using a TC-1800 colorimeter (manufactured by Tokyo Denshoku Co., Ltd.). The evaluation criteria are: AA: Brightness difference (ΔL value) is less than 5 A: Brightness difference (ΔL value) is 5 or more and less than 10 B: Brightness difference (ΔL value) is between 10 and 20. C: Brightness difference (ΔL value) is 20 or more and 30 D: Brightness difference (ΔL value) is 30 or higher

[0073] [Table 1]

[0074] [Table 2]

Claims

1. A method for forming a coating by applying a topcoat to a roofing material, The aforementioned topcoat material comprises a main component and a hardening agent. The main component comprises a polyol compound (A), The polyol compound (A) comprises a non-aqueous dispersion resin (a1), The curing agent comprises a polyisocyanate compound (B) and a silicate compound (C). The polyisocyanate compound (B) comprises a polyisocyanate compound (b1) having an isocyanate group content of less than 14% by weight and a polyisocyanate compound (b2) having an isocyanate group content of 14% by weight or more. A method for forming a coating, characterized in that the weight ratio of component (b1) to component (b2) [(b1) / (b2)] is 0.6 to 8.

2. The method for forming a coating according to claim 1, characterized in that the polyisocyanate compound (B) contains 20 to 90% by weight of the polyisocyanate compound (b1).

3. The method for forming a coating according to claim 1 or 2, characterized in that the silicate compound (C) is contained in an amount of 0.1 to 50 parts by weight per 100 parts by weight of the solid content of the polyol compound (A).

4. The method for forming a film according to claim 1 or 2, characterized in that the polyol compound (A) contains a silicone component.

5. The method for forming a film according to Claim 1, characterized in that the silicate compound (C) is a condensate (c1) of a tetraalkoxysilane containing an alkoxyl group having 1 to 2 carbon atoms and an alkoxyl group having 3 to 12 carbon atoms.

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