Aqueous foamable fire-resistant coating composition

Abstract

To provide a water-based foamable fire-resistant coating composition which has good drying properties after coating and, when applied to a substrate having an internal corner part, forms a coating layer having good cracking resistance on the internal corner part.SOLUTION: The aqueous foamable fire-resistant coating composition comprises (A) an aqueous polymer, (B) a char-forming auxiliary agent, (C) a source of carbon, (D) a foaming agent, (E) a plasticizing agent and water, wherein the plasticizing agent (E) contains an acrylic plasticizing agent (E1) as a part of its components. There are also provided a fire-resistant coating film formed from the water-based foaming fire-resistant coating composition, a method for coating a substrate using the water-based foaming fire-resistant coating composition, and a method for producing a substrate with a fire-resistant coating film using the water-based foaming fire-resistant coating composition.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an aqueous intumescent fire-resistant coating composition. [Background technology]

[0002] Intumescent fire-resistant paint is a coating material that exhibits insulating properties by expanding the coating film as the temperature rises during a fire. Fire-resistant coatings using intumescent fire-resistant paint are thin films under normal conditions that protect the substrate without damaging its shape, and in the event of a fire, they expand and carbonize, creating a flame-retardant insulating layer called char that suppresses the temperature rise of the substrate.

[0003] Conventionally, organic solvent-based paint compositions have been the mainstream of intumescent fire-resistant paints, but in recent years, aqueous intumescent fire-resistant paint compositions using water as a diluting medium have also been developed.

[0004] In order to form a coating film that is durable even when dried at room temperature, an acrylic resin emulsion is generally used as a coating film-forming component in aqueous coating compositions. However, aqueous foaming fire-resistant coating compositions containing an acrylic resin emulsion have the problem that foaming of the coating film during a fire is difficult and the fire resistance is insufficient.

[0005] In response to these problems, the applicant proposed in Patent Document 1 an aqueous foamable fire-resistant coating composition comprising a high styrene emulsion (A), a char-forming aid (B), a carbon source (C), a blowing agent (D), and water, wherein the high styrene emulsion (A) contains a copolymer of polymerizable unsaturated monomers containing styrene, and the proportion of styrene in the total of the polymerizable unsaturated monomers constituting the copolymer is 40 mass % or more. Furthermore, Patent Document 2 proposed an aqueous foamable fire-resistant coating composition containing an aqueous resin (A), a char-forming aid (B), a carbon source (C), a foaming agent (D), a plasticizer (E), and water. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2023 / 095772 [Patent Document 2] International Publication No. 2023 / 095773 Summary of the Invention [Problem to be solved by the invention]

[0007] The aqueous foamable fire-resistant coating compositions described in Patent Documents 1 and 2 contain an acrylic resin emulsion and have excellent foaming properties and fire resistance of the heated coating film. However, when applied to a substrate having an inside corner, there is a problem in that the coating layer, which is the coating film formed on the inside corner by the aqueous foamable fire-resistant coating composition, is prone to cracking.

[0008] The object of the present invention is to provide an aqueous foamable fire-resistant coating composition that dries well after application and, when applied to a substrate having an inside corner, provides a coating layer formed on the inside corner that has good crack resistance. [Means for solving the problem]

[0009] The present inventors have conducted extensive research into the above-mentioned problems, and as a result have discovered an aqueous intumescent fire-resistant coating composition that, due to the presence of a specific plasticizer, has good drying properties, good crack resistance in the coating layer formed on the inside corner, and sufficient fire resistance when heated.

[0010] That is, the present invention includes the following embodiments. Section 1. An aqueous foamable fire-resistant coating composition comprising an aqueous resin (A), a char-forming aid (B), a carbon source (C), a foaming agent (D), a plasticizer (E), and water, wherein the plasticizer (E) comprises an acrylic plasticizer (E1). Section 2. Item 2. The aqueous foamable fire-resistant coating composition according to Item 1, wherein the acrylic plasticizer (E1) has a hydroxyl group. Section 3. Item 2. The aqueous foamable fire-resistant coating composition according to Item 1, wherein the plasticizer (E) further comprises a polyether-based plasticizer (E2). Section 4. Item 4. The aqueous foamable fire-resistant coating composition according to Item 3, wherein the ratio (E1) / (E2) of the acrylic plasticizer (E1) to the polyether plasticizer (E2) is within a range of 0.1 to 10 in terms of mass ratio. Section 5. 5. The aqueous foamable fire-resistant coating composition according to any one of items 1 to 4, wherein the plasticizer (E) further contains a polyester-based plasticizer (E3). Section 6. 6. The aqueous foamable fire-resistant coating composition according to any one of items 1 to 5, wherein the plasticizer (E) comprises an acrylic plasticizer (E1), a polyether plasticizer (E2), and a polyester plasticizer (E3). Section 7. Item 7. A fire-resistant coating film formed from the aqueous foamable fire-resistant coating composition according to any one of items 1 to 6. Section 8. Item 7. A method for coating a substrate, comprising coating at least one surface of the substrate with the aqueous intumescent fire-resistant coating composition according to any one of Items 1 to 6. Section 9. A step of applying the aqueous foamable fire-resistant coating composition according to any one of items 1 to 6 to at least a part of a substrate; a step of drying and curing the coating film formed in the coating step to form a fire-resistant coating film; A method for producing a substrate with a fire-resistant coating film, comprising: [Effects of the Invention]

[0011] The aqueous intumescent fire-resistant coating composition of the present invention has excellent drying properties, making it possible to easily form a protective coating film even at room temperature. Furthermore, the coating layer formed on the inside corner using the aqueous intumescent fire-resistant coating composition is less likely to crack, and therefore can exhibit sufficient fire resistance when heated. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram of an H-beam for explaining the position of the inside corner. [Figure 2] Figure 2 is a photograph of two L-shaped steel beams. DETAILED DESCRIPTION OF THE INVENTION

[0013] As used herein, "(meth)acrylate" refers to acrylate and / or methacrylate, "(meth)acrylic acid" refers to acrylic acid and / or methacrylic acid, and "(meth)acrylamide" refers to acrylamide and / or methacrylamide. In this specification, an inside corner refers to a band-like region at a joint or corner of a member that forms an angle (for example, a nearly right angle). For example, the H-beam 1 in Figure 1 has a flat web 2 located in the center and two flanges 3 joined to the web 2 at both ends, nearly perpendicular to the web 2, and the band-like region 4 at the joint between the web 2 and the flanges 3 corresponds to the inside corner.

[0014] <Water-based resin (A)> In the present disclosure, the aqueous resin (A) is a resin that can be dissolved or dispersed in water. The type of resin is not particularly limited, and when it is in the form of dispersed particles, it may be either a single-layered or multi-layered type such as a core-shell type.

[0015] As the aqueous resin (A), any conventionally known aqueous resin can be used without any particular limitation as long as it has the ability to form a coating film, and specific examples of resin types include, but are not limited to, acrylic resins, acrylic silicone resins, urethane resins, fluororesins, epoxy resins, polyester resins, alkyd resins, melamine resins, etc. These may be used alone or in combination of two or more.

[0016] From the viewpoint of water dispersibility or water solubility, the aqueous resin (A) preferably has a carboxyl group in the molecule. When the aqueous resin (A) has a carboxyl group, the acid value of the aqueous resin (A) is preferably 3 to 100 mg KOH / g, and particularly preferably 5 to 80 mg KOH / g. Here, the acid value is the number of mg of potassium hydroxide required to neutralize the acid groups contained in 1 g of the resin nonvolatile matter, determined by a conventional method based on alkali neutralization titration.

[0017] The aqueous resin (A) may be an emulsion containing a copolymer of a carboxyl group-containing polymerizable unsaturated monomer and another polymerizable unsaturated monomer (hereinafter referred to as a "copolymer emulsion").

[0018] Examples of the carboxyl group-containing polymerizable unsaturated monomer include (meth)acrylic acid, maleic acid, crotonic acid, itaconic acid, β-carboxyethyl acrylate, and combinations thereof.

[0019] When producing the copolymer emulsion, the amount of the carboxyl group-containing polymerizable unsaturated monomer is preferably 1 to 20% by mass, particularly preferably 3 to 10% by mass, based on the total amount of the polymerizable unsaturated monomers.

[0020] Examples of other polymerizable unsaturated monomers include: alkyl or cycloalkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, tridecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl acrylate (trade name, manufactured by Osaka Organic Chemical Industry Ltd.), cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, and cyclododecyl (meth)acrylate; (Meth)acrylates having an isobornyl group, such as isobornyl (meth)acrylate; (meth)acrylates having an adamantyl group, such as adamantyl (meth)acrylate; vinyl aromatic compounds, such as styrene, α-methylstyrene, and vinyltoluene; Polymerizable unsaturated monomers having an alkoxysilyl group, such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, γ-(meth)acryloyloxypropyltrimethoxysilane, and γ-(meth)acryloyloxypropyltriethoxysilane; perfluoroalkyl (meth)acrylates such as perfluorobutylethyl (meth)acrylate and perfluorooctylethyl (meth)acrylate; polymerizable unsaturated monomers having a fluorinated alkyl group such as fluoroolefins; Monomers having a photopolymerizable functional group such as a maleimide group; nitrogen-containing polymerizable unsaturated monomers such as (meth)acrylonitrile, (meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylamide, and adducts of glycidyl (meth)acrylate with amines; hydroxyl group-containing polymerizable unsaturated monomers such as monoesters of (meth)acrylic acid with dihydric alcohols having 2 to 8 carbon atoms, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate, ε-caprolactone-modified monoesters of (meth)acrylic acid with dihydric alcohols having 2 to 8 carbon atoms, N-hydroxymethyl (meth)acrylamide, allyl alcohol, and (meth)acrylates having a polyoxyethylene chain with a hydroxyl group at the molecular terminal; Epoxy group-containing polymerizable unsaturated monomers such as glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 3,4-epoxycyclohexylethyl (meth)acrylate, 3,4-epoxycyclohexylpropyl (meth)acrylate, and allyl glycidyl ether; (Meth)acrylates having a polyoxyethylene chain with an alkoxy group at the molecular terminal; sulfonic acid group-containing polymerizable unsaturated monomers such as 2-acrylamido-2-methylpropanesulfonic acid, allylsulfonic acid, sodium styrenesulfonate, sulfoethyl methacrylate, and their sodium salts or ammonium salts; phosphoric acid group-containing polymerizable unsaturated monomers such as 2-acryloyloxyethyl acid phosphate, 2-methacryloyloxyethyl acid phosphate, 2-acryloyloxypropyl acid phosphate, and 2-methacryloyloxypropyl acid phosphate; carbonyl group-containing polymerizable unsaturated monomers such as acrolein, diacetone acrylamide, diacetone methacrylamide, acetoacetoxyethyl methacrylate, formyl styrene, and vinyl alkyl ketones having 4 to 7 carbon atoms (e.g., vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone); and combinations thereof.

[0021] From the viewpoint of fire resistance, the other polymerizable unsaturated monomer preferably contains a vinyl aromatic compound.

[0022] When a vinyl aromatic compound is used, the copolymerization ratio of the vinyl aromatic compound is preferably 55 mass% or more, and more preferably in the range of 70 to 95 mass%, of all polymerizable unsaturated monomers used in the production of the aqueous resin (A). The copolymer emulsion can be obtained by adopting a conventional method, but is preferably obtained by an emulsion polymerization method from the viewpoint of the water resistance of the coating film to be formed. In the emulsion polymerization method, the monomer components constituting the copolymer are polymerized using a polymerization initiator in the presence of water and an emulsifier, thereby obtaining a copolymer emulsion which is an aqueous dispersion of the copolymer. The aqueous resin (A) may be present in the aqueous foamable fire-resistant coating composition preferably in an amount of 5 to 50 mass %, more preferably 10 to 35 mass %, in terms of nonvolatile content, based on the total mass of nonvolatile content in the aqueous foamable fire-resistant coating composition.

[0023] In this specification, the term "non-volatile content" refers to the residue remaining after removing the volatile components, and the residue may be solid or liquid at room temperature. For example, the components remaining after heating and drying 0.3 g of a sample at 105°C for 30 minutes are considered to be non-volatile content.

[0024] <Char-forming aid (B)> The char formation aid (B) is a substance that promotes char formation when a coating film formed by the aqueous intumescent fire-resistant coating composition is exposed to fire. Lewis acids are generally considered to function as char formation aids, and specifically, phosphorus-containing compounds such as ammonium phosphate, ammonium polyphosphate, and phosphoric acid are used. Among the phosphorus-containing compounds, ammonium phosphate compounds, which are ammonium salts of phosphoric acid or polyphosphoric acid, are preferred, with ammonium polyphosphate being more preferred. In the present disclosure, other char formation aids can also be used instead of or in addition to the phosphorus-containing compounds. For example, a combination of ammonium polyphosphate and tris-(2-hydroxyethyl)isocyanurate (THEIC) is one example.

[0025] The char-forming auxiliary (B) may be present in the aqueous intumescent fire-resistant coating composition in an amount of preferably 10 to 70 mass %, more preferably 20 to 45 mass %, based on the total mass of nonvolatile components in the aqueous intumescent fire-resistant coating composition.

[0026] <Carbon source (C)> The aqueous intumescent fire-resistant coating composition contains a carbon source (C). Examples of the carbon source (C) include pentaerythritol, dipentaerythritol, polyvinyl alcohol, starch, cellulose powder, and the like.

[0027] The carbon source (C) may be present in the aqueous intumescent fire-resistant coating composition in an amount of preferably 1 to 50 mass %, more preferably 5 to 30 mass %, based on the total mass of non-volatile components in the aqueous intumescent fire-resistant coating composition.

[0028] <Blowing agent (D)> The aqueous intumescent fire-resistant coating composition of the present disclosure contains a blowing agent (D). The blowing agent (D) is one or more compounds that decompose to provide an expanding gas when exposed to heat (usually fire). The heat sufficient for the blowing agent to decompose and generate gas is typically about 90°C or higher. The temperature at which the blowing agent (D) releases gas is preferably a temperature at which the organic polymer softens and lower than the temperature at which char is formed. The aqueous intumescent fire-resistant coating composition thus formed can be sufficiently foamed to form char, thereby providing a better thermal insulation.

[0029] Examples of blowing agents (D) that can be used include melamine, melamine formaldehyde, methylol melamine, hexamethoxymethyl melamine, melamine monophosphate, melamine diphosphate, melamine polyphosphate phosphate, melamine pyrophosphate, melamine cyanurate, urea, nitrourea, dimethylurea, dicyandiamide, guanylurea phosphate, glycine, amine phosphate, azodicarbonamide, 4,4'-oxybis(benzenesulfonylhydrazide), p-toluenehydrazide, p-toluenesulfonylsemicarbazide, dinitrosopentamethylenetetramine, 5-phenyltetrazole, and diazoaminobenzene. These compounds decompose upon exposure to heat, releasing nitrogen gas. Other examples of blowing agents that can be used include compounds that release carbon dioxide, water vapor, and / or ammonia upon exposure to heat, such as ammonium borate, potassium carbonate, and citric acid derivatives, as well as expandable graphite.

[0030] The preferred blowing agent in the present disclosure can be melamine or its derivatives, used alone or in combination.

[0031] The foaming agent (D) may be present in an amount of preferably 1 to 30% by mass, more preferably 5 to 25% by mass, based on the total mass of nonvolatile components in the aqueous foamable fire-resistant coating composition.

[0032] <Plasticizer (E)> The aqueous foamable fire-resistant coating composition of the present disclosure contains a plasticizer (E) from the viewpoint of crack resistance. The plasticizer (E) is a component that remains in the coating film, and examples thereof include substances having a weight average molecular weight of 250 to 15,000, preferably 500 to 10,000.

[0033] In this specification, the weight-average molecular weight of a substance with a known chemical formula is the molecular weight calculated from the chemical formula. The weight-average molecular weight of a substance with an unknown chemical formula is the value obtained by converting the retention time (retention volume) measured using a gel permeation chromatograph (GPC) into the molecular weight of polystyrene using the retention time (retention volume) of a standard polystyrene of known molecular weight measured under the same conditions. Specifically, the measurement can be performed using a gel permeation chromatograph "HLC-8120GPC" (trade name, manufactured by Tosoh Corporation) with four columns: "TSKgel G4000HXL," "TSKgel G3000HXL," "TSKgel G2500HXL," and "TSKgel G2000HXL" (trade names, all manufactured by Tosoh Corporation), a differential refractometer as the detector, and tetrahydrofuran as the mobile phase, a measurement temperature of 40°C, and a flow rate of 1 mL / min.

[0034] The content of the plasticizer (E) is preferably within a range of 0.5 to 25% by weight, more preferably 5 to 15% by mass, based on the nonvolatile content of the coating material. In the aqueous foamable fire-resistant coating composition of the present disclosure, the plasticizer (E) contains an acrylic plasticizer (E1) as a part or all of its components from the viewpoint of fire resistance.

[0035] Acrylic plasticizer (E1) The acrylic plasticizer (E1) preferably has a weight-average molecular weight in the range of 1,000 to 10,000, more preferably 2,000 to 5,000, and is preferably a liquid substance at room temperature. Its viscosity is preferably 500 to 15,000 mPa·s, more preferably 1,000 to 12,000 mPa·s.

[0036] In this specification, the viscosity is a value measured on a sample at 25° C. using a Brookfield viscometer at a rotation speed of 60 rpm for 1 minute. Examples of (meth)acrylic acid alkyl esters that are raw materials for the acrylic plasticizer (E1) include, but are not limited to, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, neopentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and ε-caprolactone addition reaction products of hydroxyethyl (meth)acrylate, and combinations thereof.

[0037] From the viewpoint of fire resistance, the acrylic plasticizer (E1) preferably has a hydroxyl group. The acrylic plasticizer (E1) preferably has a hydroxyl value in the range of 5 to 300 mg KOH / g, particularly 10 to 200 mg KOH / g. In the case of commercially available products, the hydroxyl value is taken from the catalog value. If the hydroxyl value is unclear, it can be measured according to JIS K 0070 (1992).

[0038] The glass transition temperature of the acrylic plasticizer (E1) is preferably -20°C or lower, more preferably -60 to -30°C.

[0039] The glass transition temperature (Tg) of the acrylic plasticizer (E1) is defined as the static glass transition temperature. For example, a sample is placed in a measuring cup, and the solvent is removed by vacuum suction. Then, a differential scanning calorimeter "DSC-50Q" (Shimadzu Corporation, trade name) is used to measure the change in calorific value in the range of -100°C to 150°C at a heating rate of 3°C / min, and the first change point in the baseline on the low-temperature side is defined as the static glass transition temperature.

[0040] The content of the acrylic plasticizer (E1) in the plasticizer (E) is preferably 5% by mass or more, more preferably in the range of 10 to 80% by mass, from the viewpoints of fire resistance and cracking resistance.

[0041] Polyether plasticizer (E2) A preferred embodiment of the plasticizer (E) is an embodiment containing a polyether plasticizer (E2) in addition to an acrylic plasticizer.

[0042] The polyether plasticizer (E2) has a weight-average molecular weight of preferably 800 to 120,000, more preferably 1,000 to 10,000. When the plasticizer (E) contains the polyether plasticizer (E2) in addition to the acrylic plasticizer (E1), the coating layer formed at locations such as inside corners is less likely to crack while maintaining fire resistance.

[0043] The polyether plasticizer (E2) is a plasticizer having an ether bond in the molecule, and includes polyether plasticizers having a linear structure and polyether plasticizers having a branched structure. Examples of polyether plasticizers having a linear structure include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

[0044] Examples of polyether plasticizers having a branched structure include addition polymers of polyhydric alcohols having a branched structure, such as trimethylolpropane, glycerin, hexanetriol, pentaerythritol derivatives, sorbitol, and neopentyl glycol, with alkylene oxides, such as ethylene oxide and propylene oxide. The polyether plasticizer (E2) is preferably liquid at room temperature, and an alkylene oxide addition polymer of glycerin is a preferred example.

[0045] The hydroxyl value of such a polyether plasticizer (E2) is preferably within a range of 3 to 200 mgKOH / g, more preferably 5 to 150 mgKOH / g.

[0046] In the present disclosure, from the viewpoint of crack resistance and fire resistance of the inside corner, the ratio (E1) / (E2) of the acrylic plasticizer (E1) to the polyether plasticizer (E2) is preferably within a range of 0.1 to 10, more preferably 1.2 to 4.5, in terms of mass ratio.

[0047] Polyester plasticizer (E3) Another example of the plasticizer (E) is a polyester-based plasticizer (E3). When the plasticizer (E) contains a polyester-based plasticizer (E3) in addition to the acrylic plasticizer (E1), it has the effect of providing excellent fire resistance. Examples of the polyester-based plasticizer (E3) include adipate esters, citrate esters, benzoate esters, myristate esters, acetate esters, succinate esters, glutarate esters, sebacate esters, and combinations thereof. Plasticizers using adipic acid as a raw material are particularly preferred.

[0048] The amount of the polyester plasticizer (E3) in the plasticizer (E) is preferably within a range of 10 to 90% by mass, more preferably 25 to 75% by mass.

[0049] In the present disclosure, when the plasticizer (E) includes all of the acrylic plasticizer (E1), the polyether plasticizer (E2), and the polyester plasticizer (E3), the mass ratios thereof are based on the total mass of these (E1), (E2), and (E3), and are as follows: The acrylic plasticizer (E1) is preferably 5 to 79% by mass, more preferably 10 to 65% by mass, The polyether plasticizer (E2) is preferably 1 to 75% by mass, more preferably 5 to 60% by mass, The content of the polyester plasticizer (E3) is preferably in the range of 20 to 94% by mass, particularly preferably 30 to 85% by mass.

[0050] <Water-based foamable fire-resistant coating composition> The aqueous intumescent fire-resistant coating composition of the present disclosure contains water. Water is a dilution medium, and the amount of water in the aqueous intumescent fire-resistant coating composition can be appropriately selected by those skilled in the art, but is preferably within the range of 5 to 60 mass %, more preferably 10 to 50 mass %, based on the total mass of the nonvolatile components in the aqueous intumescent fire-resistant coating composition.

[0051] The aqueous intumescent fire-resistant coating composition of the present disclosure can optionally include other components such as, but not limited to, pigments, pigment dispersants, coalescents, fibers, catalysts, organic solvents, additives for modifying melt viscosity, rheology modifiers, and curing agents.

[0052] Among these, examples of pigments include colored pigments such as titanium dioxide (white pigment), carbon black, and iron oxide; and filler pigments such as baryte, talc, calcium carbonate, kaolin, and clay.

[0053] The pigment may be present in the aqueous intumescent fire-resistant coating composition in an amount of preferably 1 to 40 mass %, more preferably 5 to 30 mass %, based on the total mass of nonvolatile components in the aqueous intumescent fire-resistant coating composition.

[0054] The coalescing aid is a high-boiling organic solvent compatible with the aqueous resin (A), and is a component that remains in the coating film even after the water has evaporated and gradually volatilizes while promoting the fusion of the aqueous resin (A) particles. The weight-average molecular weight of the coalescing aid is, for example, less than 250. Specific examples of the coalescing aid include ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, ethylene glycol monohexyl ether, ethylene glycol mono-2-ethylhexyl ether, diethylene glycol monomethyl ether, diethylene glycol diethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol dibutyl ether, diethylene glycol monophenyl ether, diethylene glycol monohexyl ether, diethylene glycol monobenzyl ether, diethylene glycol mono-2-ethylhexyl ether, and triethylene glycol. Examples of the glycol ether compounds include diethyl ether, triethylene glycol monobutyl ether, polyethylene glycol monobutyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol monophenyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, and tripropylene glycol monobutyl ether; and ester compounds such as 2-isobutoxyethyl benzoate, 2,2,4-trimethylpentanediol monoisobutyrate, and 2,2,4-trimethylpentanediol diisobutyrate.

[0055] When the aqueous foamable fire-resistant coating composition of the present disclosure contains a film-forming aid in addition to the plasticizer (E), the content of the film-forming aid is preferably in the range of 0.1 to 15 mass%, more preferably 0.5 to 10 mass%, based on the non-volatile content of the coating.

[0056] <Painting method> The present disclosure further relates to a method for coating a substrate, which comprises coating the above-described aqueous intumescent fire-resistant coating composition on a surface of the substrate.

[0057] The aqueous foamable fire-resistant coating composition of the present disclosure can be cured and / or dried at ambient temperatures, for example, from 5°C to 40°C, but may be dried by heating as needed. In the present disclosure, the dry film thickness of the layer of the aqueous intumescent fire-resistant coating composition can be appropriately selected depending on the application. For example, in the case of cellulose-based fire-resistant applications (for example, application to structures such as office buildings), the thickness is preferably 100 μm to 8 mm, more preferably 200 μm to 4 mm.

[0058] In this specification, the dry film thickness can be measured by an electromagnetic film thickness. Applying the aqueous intumescent fire-resistant coating composition to the surface of a substrate includes applying the aqueous intumescent fire-resistant coating composition to at least one surface of the substrate.

[0059] The present disclosure also provides a method for coating the aqueous intumescent fire-resistant coating composition on at least a portion of a substrate, a step of drying and curing the coating film formed in the coating step to form a fire-resistant coating film; The present invention relates to a method for producing a substrate with a fire-resistant coating film,

[0060] The aqueous foamable fire-resistant coating composition of the present disclosure can be applied to various substrates that require resistance to heat from flames, etc. Examples of the substrate are not particularly limited, and include metals such as steel frames, aluminum, and galvanized steel sheets, as well as wallpaper, plywood, wood, inorganic boards, concrete, mortar, FRP, plastics, paper, cloth, fibers, synthetic resins, rubber, silicone, and electric wires and cables. The shape of the substrate is not particularly limited.

[0061] When the aqueous foamed fire-resistant coating composition of the present disclosure is applied to the steel frame of an existing structure, the steel frame may be subjected to a surface treatment such as rust removal, and then, if necessary, a primer paint may be applied to the surface-treated steel frame, and then the aqueous foamed fire-resistant coating composition of the present disclosure may be applied. Alternatively, after applying the aqueous foamed fire-resistant coating composition of the present disclosure, a known top coat may be applied.

[0062] Examples of structures include land structures and marine structures, and particularly suitable structures include buildings defined in Articles 21 and 27 of the Building Standards Act. Specific examples include buildings, schools, hospitals, hotels, movie theaters, stores, warehouses, airports, etc. The coating method is not particularly limited, and can be easily applied by common methods such as brush, trowel, roller, spray, etc., and it is possible to not only apply smoothly but also form a thick film with an uneven pattern. These coating methods are appropriately selected depending on the intended use of the substrate. [Example]

[0063] The present invention will now be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the following examples, "parts" and "%" mean "parts by mass" and "% by mass," respectively.

[0064] Preparation of aqueous foamable fire-resistant coating composition Examples 1 to 17 and Comparative Examples 1 to 2 The components shown in Table 1 below were placed in a container and mixed using a disper until uniform, yielding aqueous intumescent fire-resistant coating compositions (X-1) to (X-19). Table 1 shows the mass including the volatile components. Each aqueous intumescent fire-resistant coating composition was used to carry out the following evaluation tests. The results are also shown in Table 1. In the table, ◎ and ◯ ranks were judged as passing, and △ and × ranks were judged as failing.

[0065] [Table 1]

[0066] (Note 1) 45% emulsion (A-1): styrene / n-butyl acrylate / 2-ethylhexyl acrylate / methacrylic acid = 60 / 2 / 30 / 8 emulsion polymer, non-volatile content 45% (Note 2) Acrylic plasticizer (E1-1): Viscosity 10,300 mPa·sec, weight average molecular weight 2,500, hydroxyl value 120 mgKOH / g, 2-ethylhexyl acrylate / hydroxyethyl acrylate = 70 / 30 copolymer, glass transition temperature -55°C, liquid (Note 3) Acrylic plasticizer (E1-2): Viscosity 930 mPa·sec, weight average molecular weight 2300, hydroxyl value 17 mgKOH / g, 2-ethylhexyl acrylate / hydroxybutyl acrylate = 95.5 / 4.5 copolymer, glass transition temperature -53°C, liquid (Note 4) Acrylic plasticizer (E1-3): Viscosity 800 mPa·sec, weight average molecular weight 3500, hydroxyl value 0 mgKOH / g, 2-ethylhexyl acrylate polymer, glass transition temperature -53°C, liquid (Note 5) Polyether plasticizer (E2-1): Polyethylene glycol, weight average molecular weight 2000, hydroxyl value 56, waxy (Note 6) Polyether plasticizer (E2-2): Polyethylene glycol, weight average molecular weight 8000, hydroxyl value 14, waxy (Note 7) Polyether plasticizer (E2-3): Polyoxyethylene adduct of glycerin, ethyleneoxy adduct mole number 26, weight average molecular weight 1240, hydroxyl value 127, liquid (Note 8) Polyester plasticizer (E3-1): Adipic acid polyester, weight average molecular weight 800, liquid.

[0067] 1.Drying property Each aqueous intumescent fire-resistant coating composition was spray-painted onto the inner surface (including the corner) of an L-shaped steel plate (a commercially available steel plate 6 mm thick with dimensions of 75 mm vertically, 75 mm horizontally, and 150 mm long, bent at a right angle), so that the dry film thickness on the flat surface was 1.5 mm, and the plate was dried at 23°C and 50% RH for 24 hours to obtain an L-shaped test specimen. Drying properties were evaluated by the hardness of the coating film. Specifically, the Shore A hardness of the coating film formed on the flat surface of the test specimen obtained above was measured using a Type A durometer (Shore A) in accordance with JIS K6253-3:2012, and evaluated according to the following criteria. ◎: Shore A hardness is 40 or more, and the coating film does not deform at all when pressed with a finger ○: Shore A hardness is 30 or more but less than 40, and the coating film does not deform at all when pressed with a finger △: Shore A hardness is 20 or more but less than 30, and the coating film deforms slightly when pressed with a finger ×: Shore A hardness is less than 20, and the coating film is easily deformed when pressed with a finger.

[0068] 2. Flat part cracking resistance The state of cracks on the flat surface of the L-shaped specimen obtained above was visually observed. ◎: No cracks at all ○: Slight cracks are observed, but they do not reach the substrate △: Few cracks are observed, and some cracks reach the base material. ×: Significant cracks were observed, and some cracks reached the base material.

[0069] 3.Crack resistance at inside corners The cracks in the coating layer formed at the inside corners of the L-shaped specimens obtained above were visually observed. In Figure 2, the L-shaped specimen on the right side had good resistance to cracking at the inside corners (evaluated as ⊚), while the specimen on the left side had poor resistance to cracking at the inside corners (evaluated as △). ◎: No cracks at all ○: Slight cracks are observed, but they do not reach the substrate △: Few cracks are observed, and some cracks reach the base material. ×: Significant cracks were observed, and some cracks reached the base material.

[0070] 4.Fire resistance Each aqueous intumescent fire-resistant coating composition was applied to a blasted steel plate measuring 100 mm x 100 mm x 3.2 mm so that the dry film thickness was 1.0 mm, and the resulting panel was dried at 23°C for 7 days to prepare a test panel, which was then subjected to a simple fire resistance test using a cone calorimeter. Specifically, a thermocouple was attached to the back side of the test panel, and the test panel was heated at a heating intensity of 50 kW / m 2 The samples were subjected to an ignition test using a cone calorimeter, and the fire resistance was evaluated according to the following criteria. The fire resistance was evaluated by recording the thermocouple temperature 20 minutes after ignition and using the following criteria. ◎: Thermocouple temperature after 20 minutes is less than 340℃ 〇: Thermocouple temperature after 20 minutes is 340℃ or higher but less than 350℃ △: Thermocouple temperature after 20 minutes is 350℃ or more but less than 360℃ ×: Thermocouple temperature after 20 minutes is 360°C or higher

Claims

1. An aqueous foamable fire-resistant coating composition comprising an aqueous resin (A), a char-forming aid (B), a carbon source (C), a foaming agent (D), a plasticizer (E), and water, wherein the plasticizer (E) comprises an acrylic plasticizer (E1).

2. The aqueous foamable fire-resistant coating composition according to claim 1, wherein the acrylic plasticizer (E1) has a hydroxyl group.

3. The aqueous foamable fire-resistant coating composition according to claim 1, wherein the plasticizer (E) further comprises a polyether-based plasticizer (E2).

4. 4. The aqueous foamable fire-resistant coating composition according to claim 3, wherein the ratio (E1) / (E2) of the acrylic plasticizer (E1) to the polyether plasticizer (E2) is within the range of 0.1 to 10 in mass ratio.

5. The aqueous foamable fire-resistant coating composition according to claim 1, wherein the plasticizer (E) further comprises a polyester-based plasticizer (E3).

6. The aqueous foamable fire-resistant coating composition according to claim 1, wherein the plasticizer (E) further comprises a polyether-based plasticizer (E2) and a polyester-based plasticizer (E3).

7. A fire-resistant coating film formed from the aqueous foamable fire-resistant coating composition according to any one of claims 1 to 6.

8. A method for coating a substrate, comprising coating at least one surface of the substrate with the aqueous intumescent fire-resistant coating composition according to any one of claims 1 to 6.

9. A step of applying the aqueous foamable fire-resistant coating composition according to any one of claims 1 to 6 to at least a part of a substrate; a step of drying and curing the coating film formed in the coating step to form a fire-resistant coating film; A method for producing a substrate with a fire-resistant coating film, comprising:

Images