JP7683909B2 - Water-based foamable fireproof coating composition - Google Patents

Description

The present invention relates to an aqueous foamable fire-resistant paint composition that contains water as a diluting medium.

Because steel loses its strength rapidly at around 500°C, steel-framed structures collapse in the event of a fire, making it impossible to evacuate or put out the fire. For this reason, the Building Standards Act requires that a fire-resistant coating with insulating properties be applied to the steel frame of a structure in order to maintain its strength for a specified period of time even in the event of a fire. Examples of fire-resistant coating materials include rock wool fire-resistant coating material and foam fire-resistant paint. Rock wool fire-resistant coating material is inexpensive and widely available on the market, but it requires a thickness of 1 cm to several cm to demonstrate fire resistance, and there is an issue that it is difficult to spray.

On the other hand, foaming fireproof paint is a coating material that exhibits insulating properties by expanding the coating film as the temperature rises during a fire. Unlike rock wool, fireproof coating using foaming fireproof paint is a thin film under normal conditions and does not damage the shape of the structure itself. In the event of a fire, it expands and carbonizes, and the flame-retardant insulating layer called char suppresses the temperature rise of the steel and delays the collapse of the structure.

In Patent Document 1, the applicant proposed a foaming fireproof paint that contains a hydrolyzable silyl group-containing resin, a plasticizer, a foaming agent, and a carbonizing agent. This paint is easy to apply thickly, and produces a protective coating film that has excellent physical properties such as quick drying, internal curing, and water resistance, and can form a foamed layer with excellent fire resistance under fire conditions.

However, the foaming fireproof paint described in Patent Document 1 contains an organic solvent as a dilution medium, which causes odor problems when applied in hospitals, schools, etc. In addition, there are problems such as the inability to carry out electrical work in parallel due to the scattering of the organic solvent, and so there is an increasing demand for water-based foaming fireproof paint that uses water as a dilution medium.

For example, Patent Document 2 discloses a water-based foaming fireproof paint that contains an acrylic resin emulsion, a polyhydric alcohol, a foaming agent, a flame-retardant dehydrating agent, and an alkali-thickening emulsion. Although this paint composition has excellent workability and fire resistance, the water resistance of the coating film is insufficient, limiting its range of application.

JP 2018-159065 A JP 2015-59180 A

The objective of the present invention is to propose a water-based foamable fireproof paint composition that has excellent fire resistance during fires and water resistance of the coating film under normal conditions.

Incidentally, intumescent fireproof paints contain a char-forming agent, a carbon source, and a foaming agent to generate char in the event of a fire. The mechanism by which these ingredients generate char is unclear, but it is generally believed to be as follows: The flame raises the temperature around the coating, causing the char-forming agent contained in the coating to thermally decompose, generating Lewis acid. This Lewis acid then decomposes the carbon source, forming a char layer. Meanwhile, the high temperature decomposes the foaming agent contained in the coating, generating gas, which foams the molten coating-forming components, expanding the char layer and generating char.

The present inventors have conducted extensive research into methods for improving the water resistance of an aqueous foamable fire-resistant coating composition under normal conditions.
As a result, by using a specific compound as a carbon source used to generate char in the foaming fire-resistant paint composition, it was possible to successfully obtain a coating film that has excellent water resistance under normal conditions without significantly reducing fire resistance in the event of a fire.

That is, the present invention provides
Item 1.
An aqueous intumescent fire-resistant coating composition comprising a resin, a char-forming adjuvant, a carbon source, a foaming agent, and water, wherein the carbon source comprises a polyhydric alcohol phosphate ester , and the polyhydric alcohol phosphate ester is 4-hydroxymethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane 1-oxide .
Item 2.
Item 2. The aqueous foamable fire-resistant coating composition according to item 1, wherein the polyhydric alcohol source of the polyhydric alcohol phosphate ester is pentaerythritol.
Item 3.
Item 3. The aqueous foamable fire-resistant coating composition according to item 1 or 2 , wherein the resin contains a carboxyl group.
Item 4.
Item 4. The aqueous foamable fireproof coating composition according to any one of items 1 to 3 , wherein the acid value of the resin is 3 to 100 mgKOH/g.
Item 5.
5. The aqueous foamable fireproof coating composition according to any one of items 1 to 4 , wherein the resin is a copolymer emulsion of a carboxyl group-containing polymerizable unsaturated monomer and another polymerizable unsaturated monomer.
Item 6.
Item 6. The aqueous foamable fireproof coating composition according to item 5 , wherein the copolymerization amount of the carboxyl group-containing polymerizable unsaturated monomer is within the range of 1 to 10 mass% of the total polymerizable unsaturated monomers.
Section 7.
Item 7. The aqueous foamable fireproof coating composition according to any one of items 1 to 6 , further comprising a crosslinking agent.
Section 8.
Item 8. The aqueous foamable fireproof coating composition according to item 7 , wherein the crosslinking agent is a polyvalent metal compound.
Item 9.
Item 10. The aqueous foamable fireproof coating composition according to any one of items 1 to 8 , which is a one-liquid type coating composition.
Item 10. The aqueous foamable fireproof coating composition according to any one of items 1 to 8 , which is a two-component coating composition.
Item 11. The aqueous foamable fireproof coating composition according to item 10, which is a two-liquid type coating composition to be used by mixing a first component (I) and a second component (II) immediately before use, the first component containing a resin, the second component containing a crosslinking agent, and the first component and/or the second component containing a carbon source, a char-forming auxiliary, a foaming agent, and water.
Item 12.
A method for coating a substrate, comprising coating a surface of the substrate with the aqueous foamable fireproof coating composition according to any one of items 1 to 11 .
Item 13.
A method for protecting a structure from heat and fire, comprising applying the aqueous foamable fire-resistant coating composition according to any one of items 1 to 11 to a surface of a substrate;
Regarding.

According to the present invention, an aqueous foamable fire-resistant coating composition is obtained that can form a coating film that has excellent physical properties such as water resistance under normal conditions. Furthermore, the coating film formed by this aqueous foamable fire-resistant coating composition is resistant to deterioration by rainwater, etc., and expands at high temperatures such as during a fire even after a long time has passed since application, demonstrating excellent heat insulation properties, thereby delaying the collapse of structures due to heat.

1 is a photograph showing the state of char after a fire resistance test of the aqueous fire-resistant coating composition of Example 5, conducted in Test Example 2.

The aqueous foamable fire-resistant coating composition of the present invention contains a resin, a char-forming aid, a carbon source, a foaming agent, and water.

<Resin>
In the present invention, the resin used is a resin that is soluble or dispersible in water. There is no particular limitation on the type of resin, and when the resin is in the form of dispersed particles, it may be a single-layered or multi-layered type such as a core-shell type.

Examples of resins that can be used are not particularly limited and may be any conventionally known resin that has the ability to form a coating film. Specific examples include, but are not limited to, acrylic resin emulsion, acrylic silicone resin emulsion, urethane resin emulsion, fluororesin emulsion, epoxy resin emulsion, polyester resin emulsion, alkyd resin emulsion, and melamine resin emulsion. These may be used alone or in combination of two or more.

The resin preferably contains a carboxyl group.

In the present invention, when the resin has carboxyl groups, the acid value of the resin is preferably in the range of 3 to 100 mgKOH/g, particularly 5 to 80 mgKOH/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 mass of the resin nonvolatile matter, determined by a conventional method based on alkali neutralization titration.

The resin may be a copolymer emulsion of a carboxyl group-containing polymerizable unsaturated monomer and other polymerizable unsaturated monomers.

Carboxyl group-containing polymerizable unsaturated monomers include (meth)acrylic acid, maleic acid, crotonic acid, itaconic acid, β-carboxyethyl acrylate, and combinations thereof.

When producing a copolymer emulsion, the amount of the carboxyl group-containing polymerizable unsaturated monomer copolymerized is preferably within the range of 1 to 20% by mass, and more preferably 3 to 10% by mass, of the total polymerizable unsaturated monomers.

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 Co., 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 and amines;
hydroxyl group-containing polymerizable unsaturated monomers such as monoesters of (meth)acrylic acid and 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 and dihydric alcohols having 2 to 8 carbon atoms, N-hydroxymethyl (meth)acrylamide, allyl alcohol, and (meth)acrylates having a polyoxyethylene chain whose molecular terminal is a hydroxyl group;
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)acrylate having a polyoxyethylene chain whose molecular terminal is an alkoxy group;
Sulfonic acid group-containing polymerizable unsaturated monomers such as 2-acrylamido-2-methylpropanesulfonic acid, allylsulfonic acid, sodium styrenesulfonate, sulfoethyl methacrylate, and sodium or ammonium salts thereof;
Phosphate 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.

As the other polymerizable unsaturated monomer, from the viewpoint of water resistance and fire resistance, it is preferable to use an alkyl or cycloalkyl (meth)acrylate and/or a vinyl aromatic compound.

The copolymer emulsion can be obtained by adopting a conventional method, but an emulsion polymerization method is preferred from the viewpoint of the water resistance of the coating film formed. In the emulsion polymerization, a conventionally used ionic or nonionic surfactant can be used.

The resin may be present in the aqueous foamable fire-resistant coating composition in an amount of 5 to 50% by mass, more preferably 10 to 35% by mass, based on the total mass of the non-volatile components in the aqueous foamable fire-resistant coating composition.

In the present invention, the mass of the non-volatile components in the aqueous foamable fireproof coating composition can be calculated by placing a known mass (e.g., 0.3 g) of the aqueous foamable fireproof coating composition as a sample in a pre-weighed aluminum dish, heating the sample in an oven at 105°C for 30 minutes, measuring the mass of the dish again, and calculating the mass of the non-volatile components from the mass of the sample before and after heating (see ASTM D2697).

Unless otherwise specified, the mass % values in this specification are calculated based on the total mass of non-volatile components in the aqueous foamable fireproof coating composition. The non-volatile content means the residue after removing the volatile components, and the residue may be either solid or liquid at room temperature.

<Char formation aid>
The char formation aid is intended to promote the formation of char when a coating film formed by the aqueous intumescent fireproof coating composition is exposed to fire, and specifically, a phosphorus-containing compound such as ammonium phosphate, ammonium polyphosphate, phosphoric acid, etc. is used. Among the phosphorus-containing compounds, ammonium phosphate compounds, which are ammonium salts of phosphoric acid or polyphosphoric acid, are preferred, and ammonium polyphosphate is more preferred. In the present invention, it is also possible to use other char formation aids instead of or in addition to the phosphorus-containing compound. For example, a combination of ammonium polyphosphate and tris-(2-hydroxyethyl)isocyanurate (THEIC) is one example.

The char-forming auxiliary may be present in the aqueous foamable fire-resistant coating composition in an amount of 10 to 70% by weight, more preferably 20 to 45% by weight, based on the total weight of the non-volatile components in the aqueous foamable fire-resistant coating composition.

<Carbon source>
The aqueous intumescent fire-resistant coating composition contains a carbon source.

In the present invention, the carbon source contains a polyhydric alcohol phosphate ester as one of its components.

Examples of polyhydric alcohols include pentaerythritol, dipentaerythritol, polyvinyl alcohol, starch, cellulose powder, etc., with pentaerythritol being particularly preferred.

In the present invention, from the viewpoints of water resistance, fire resistance, and durability in particular, it is suitable to use 4-hydroxymethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane 1-oxide as the polyhydric alcohol phosphate ester.

4-Hydroxymethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane 1-oxide is a compound represented by the following general formula:

In the present invention, the carbon source may be present in the aqueous foamable fireproof coating composition in an amount of preferably 1 to 50% by mass, more preferably 5 to 30% by mass, based on the total mass of the non-volatile components in the aqueous foamable fireproof coating composition.

<Foaming Agent>
The water-based intumescent fire-resistant coating composition of the present invention contains a spumific. A spumific is one or more compounds that decompose to provide an expanding gas when exposed to heat, usually fire. The heat required for the spumific to decompose and generate gas is usually about 90° C. or higher.

The temperature at which the blowing agent releases gas is preferably a temperature at which the organic polymer becomes soft, but lower than the temperature at which char is formed. The aqueous foaming underground coating composition thus formed will foam sufficiently and then form char, making it a better insulator.

Examples of the blowing agent 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. The above compounds decompose when exposed to heat, releasing nitrogen gas. In addition, compounds that release carbon dioxide, water vapor, and/or ammonia when exposed to heat, such as ammonium borate, potassium carbonate, and citric acid derivatives, and expandable graphite can also be used as blowing agents. The preferred blowing agent can be melamine or its derivatives, used alone or in combination.

The foaming agent 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 the non-volatile components in the aqueous foamable fireproof coating composition.

The aqueous foamable fireproof coating composition of the present invention may further contain one or more of the following: a crosslinking agent, a pigment, a plasticizer, and a film-forming aid.

<Crosslinking Agent>
In the present invention, the aqueous foamable fireproof coating composition may contain a crosslinking agent as desired. In the present invention, a polyvalent metal compound is preferably used as the crosslinking agent.
The polyvalent metal compound has a metal capable of forming a metal bridge with a functional group contained in the resin. A metal bridge is a bridge structure that connects resin molecules via a metal. The inventors believe that such a metal bridge is decomposed at a lower temperature than a bridge structure formed by a covalent bond between nonmetals, and therefore forms a strong char when exposed to flame without preventing the expansion of the coating film.

The polyvalent metal compound is a polyvalent metal compound containing a metal element that can have an ionic valence of divalent or more, preferably divalent to tetravalent, and examples of the polyvalent metal compound include compounds containing metal elements such as Mg, Ca, Ba, Fe, Cu, Zn, Al, Ti, Si, Zr, and Mn.
As the polyvalent metal compound, either an inorganic metal compound or an organic metal compound can be suitably used.

Examples of inorganic metal compounds include metal oxides, metal hydroxides, metal nitrates, metal sulfates, and metal phosphates. Among these, metal oxides are preferred.

Examples of organometallic compounds include organic acid metal salts, metal alkoxides, and organometallic complexes. Among these, the use of organic acid metal salts is preferred.

Examples of organic acids that make up organic acid metal salts include formic acid, acetic acid, propionic acid, butyric acid, zinc oxalate, valeric acid, α-methylbutyric acid, salicylic acid, stearic acid, and lactic acid.

In addition, compounds having functional groups capable of reacting with the functional groups contained in the resin can also be used as crosslinking agents. Examples of such compounds include polyoxazoline compounds, carbodiimide compounds, polyamines, hydrazine compounds, polyhydrazide compounds, and polyisocyanate compounds.

When the aqueous foamable fireproof coating composition of the present invention uses a crosslinking agent, the amount of the crosslinking agent can be within the range of 0.01 to 10% by mass, preferably 0.1 to 5% by mass, based on the non-volatile mass of the resin.

<Pigments>
The aqueous foamable fireproof coating composition of the present invention may optionally contain a pigment. The pigment does not include the above-mentioned polyvalent metal compounds. As the color pigment, any pigment known in the coating field may be used, and examples thereof include colored pigments such as titanium dioxide (white pigment), carbon black, and iron oxide; filler pigments such as baryte, talc, calcium carbonate, kaolin, and clay; and fibers. The pigment may be present in the aqueous foamable fireproof coating composition in an amount of 1 to 40% by mass, preferably 5 to 30% by mass, based on the total mass of the nonvolatile components in the aqueous foamable fireproof coating composition.

<Plasticizer and/or Film-Forming Aid>
The aqueous foamable fire-resistant coating composition of the present invention may optionally contain a plasticizer and/or a coalescent.
The plasticizer is a compound that remains in the coating film and is liquid at room temperature, and any compound known in the coating field can be used. Specific examples of the plasticizer include fatty acid ester plasticizers, phosphate ester plasticizers, and epoxy plasticizers.

On the other hand, a film-forming aid is a high-boiling organic solvent that is compatible with resins, and is a component that remains in the coating film even after the water has evaporated and gradually evaporates while promoting the fusion of resin particles. Specific examples of film-forming aids 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, and diethylene glycol mono 2-ethylhexyl ether. , glycol ether compounds such as triethylene glycol monomethyl 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 2,2,4-trimethylpentanediol monoisobutyrate and 2,2,4-trimethylpentanediol diisobutyrate.

When a plasticizer and a film-forming aid are included, the content is within the range of 0.1 to 15 mass %, preferably 0.5 to 10 mass %, based on the total mass of the non-volatile components in the aqueous foamable fireproof coating composition.

<Water-based foamable fireproof coating composition>
The water-based foamable fire-resistant coating composition of the present invention can optionally contain other components, such as, but not limited to, pigment dispersants, catalysts, organic solvents, additives for modifying melt viscosity, rheology modifiers, and curing agents.

The form of the aqueous foamable fire-resistant coating composition of the present invention is not particularly limited. It may be a one-component type.
When the aqueous foamable fireproof coating composition of the present invention contains a crosslinking agent, it is preferably a two-component coating composition in which the first component (I) and the second component (II) are mixed immediately before use, the first component contains a resin, the second component contains a crosslinking agent, and the first component and/or the second component contains a carbon source, a char formation auxiliary, a foaming agent, and water.

<Painting method>
The present invention further relates to a method for coating a substrate, which comprises coating a surface of the substrate with the above-mentioned aqueous foamable fire-resistant coating composition.

The aqueous foamable fire-resistant coating composition of the present invention can be cured and/or dried at ambient temperatures, for example, from -5°C to 40°C. It is therefore suitable for application to large structures where heat curing is not practical.

In the present invention, the dry film thickness of the layer of the aqueous foamable fireproof coating composition can be appropriately selected depending on the application. Typically, for cellulose-based fireproofing applications (e.g., application to buildings such as office buildings), the thickness is 100 μm to 8 mm, preferably 200 μm to 4 mm.

The present invention further relates to a method for protecting a structure from flame or heat, which comprises applying the above-mentioned aqueous foamable fire-resistant coating composition to a substrate surface.

The aqueous foamable fire-resistant coating composition of the present invention can be applied to a variety of substrates.

Examples of substrates 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, silicon, and electric cables. Examples of structures include terrestrial structures and marine structures, and particularly suitable structures include buildings as defined in Articles 21 and 27 of the Building Standards Act. Specific examples include buildings, schools, hospitals, hotels, movie theaters, stores, warehouses, airports, etc.

When applying the aqueous foaming fireproof paint composition of the present invention to the steel frame of an existing structure, the aqueous foaming fireproof paint of the present invention can be applied after surface preparation such as rust removal and, if necessary, application of an undercoat paint. In addition, after application of the aqueous foaming fireproof paint composition of the present invention, a known topcoat paint can be applied.

There are no particular limitations on the application method, and the coating can be easily applied using common methods such as brushing, troweling, rollers, and spraying. It is possible to apply the coating not only smoothly, but also to form a thick film with an uneven pattern. These application methods are appropriately selected depending on the intended use of the substrate.

The present invention will be further described below with reference to examples. Here, "parts" and "%" mean "parts by mass" and "% by mass", respectively.

Example 1
<Production of one-liquid type aqueous foamable fireproof coating composition>
Example 1
The following components were placed in a container and mixed with a planetary mixer until homogenous, to obtain a one-liquid type water-based foamable fire-resistant coating composition (X-1).

[Composition of aqueous foamable fireproof coating composition (X-1)]
Deionized water 20 parts Melamine 8.09 parts Pentaerythritol phosphate ester (Note 1) 8.09 parts Titanium oxide 8 parts Ammonium polyphosphate 24.27 parts Rock wool fiber 3 parts 50% acrylic resin emulsion (Note 2) 17.26 parts 2,2,4-trimethylpentanediol monoisobutyrate 5.9 parts Thickener 0.2 parts.

(Note 1) Pentaerythritol phosphate ester: 4-hydroxymethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane 1-oxide (Note 2) 50% acrylic resin emulsion: styrene/methacrylic acid/2-ethylhexyl acrylate/hydroxyethyl acrylate=85/8/6.1/0.9, emulsion polymer, non-volatile content 50%, acid value 40 mgKOH/g.

<Production of two-liquid type aqueous foamable fireproof coating composition>
Example 2
The aqueous foamable fireproof coating composition (X-1) obtained in Example 1 was used as the first component, and 1.625 parts of a 10% aqueous zinc acetate solution was added as the second component and mixed with stirring to produce an aqueous foamable fireproof coating composition (X-2).

Examples 3 to 4 and Comparative Example 1
Each of the water-based foamable fireproof coating compositions (X-3) to (X-5) was produced in the same manner as in Example 1 or Example 2, except that the blending compositions were as shown in Table 1.

Test Example 1
Each of the aqueous foamable fireproof coating compositions obtained in the above Examples and Comparative Examples was subjected to a simple fire resistance test using a cone calorimeter, and was evaluated for durability and blister resistance.

(*) Simple fire resistance test: A blasted steel plate measuring 100 x 100 x 3.2 mm was painted with "ESCO NB Primer" (product name, Kansai Paint Co., Ltd., modified epoxy resin rust-preventive paint) and dried. Each aqueous foamable fire-resistant paint composition was then painted so that the dry film thickness was 1.0 mm, and the plate was dried at 23°C for 3 days and at 50°C for 1 day to create a test panel.
A thermocouple was attached to the back side of the test panel, and an ignition test was performed using a cone calorimeter with a heating intensity of 50 kW/ ^m2 . The temperature of the thermocouple was measured after 20 minutes, and evaluated according to the following criteria.
○: Thermocouple temperature is 500℃ or less.
×: The temperature of the thermocouple exceeds 500°C.

(*) Durability:
The same test panels as those prepared in the above simple fire resistance test were prepared, and the coating film was deteriorated by repeating a cycle of immersion in 20°C water for 18 hours, cooling to -20°C for 3 hours, and heating to 50°C for 3 hours 10 times, and then subjected to the simple fire resistance test in the same manner. As a result, the deteriorated coating film had a higher temperature than the new coating film.

The values in Table 1 are the temperature difference between the temperature of the rear surface of the test panel after 20 minutes in the cone calorimeter test, obtained by subtracting the temperature of the new coating from the temperature of the deteriorated coating. The smaller the value in the table, the less the fire resistance has decreased even when the coating has deteriorated, and the better the durability is.
(*) Blister resistance Two blast steel panels measuring 150 x 70 x 3.2 mm were coated with each aqueous fireproof coating composition to a dry thickness of 2 mm and dried at 23°C for 7 days. One panel was left as is, and the other panel was further coated with "Cosmo Silicone" (product name, Kansai Paint Co., Ltd., aqueous reactive curing acrylic silicone coating) to a dry thickness of 50 μm and dried at 23°C for 7 days to prepare a test panel. Each test panel with and without topcoat was immersed in water at 23°C for 3 weeks, dried at 50°C for 3 days, and evaluated for appearance according to the following criteria.
◎: No change at all before and after immersion
○: Very slight swelling is observed.
△: Blisters are clearly observed.
×: A large and noticeable bulge is observed.

Test Example 2
(*) Fire resistance test Example 5
A two-liquid type aqueous foamable fireproof coating composition (X-6) was produced with the following formulation. A steel material (size 300 mm x 300 mm x 4.5 mm) equipped with a thermocouple was prepared, and the aqueous foamable fireproof coating composition (X-6) was applied to this with a trowel so that the dry film thickness was 3.3 mm, and dried at 23 ° C for 7 days to obtain a test specimen. This test specimen was placed in a furnace that was heated to a predetermined temperature with respect to the elapsed time so as to obtain a temperature rise curve specified by ISO 834, and subjected to a fire resistance test. The time it took for the temperature of the test specimen to reach 500 ° C. was 89 minutes. The test specimen after the fire resistance test of Example 5 was covered with char as shown in FIG. 1.

[Composition of aqueous foamable fireproof coating composition (X-6)]
First component 25% zinc acetate aqueous solution 0.65 parts Deionized water 18 parts Melamine 8.09 parts Pentaerythritol phosphate ester (Note 1) 8.09 parts Titanium oxide 7.94 parts Ammonium polyphosphate 24.27 parts Rock wool fiber 0.5 parts Second component 50% acrylic resin emulsion (Note 2) 17.26 parts Carbon black 0.01 parts 2,2,4-trimethylpentanediol monoisobutyrate 5.9 parts Thickener 0.1 parts.

Comparative Example 2
The time to reach 500°C was measured in the same manner as in Example 5 except for the following composition, and was found to be 77 minutes. In Comparative Example 2, the time to reach 500°C was shorter than that in Example 5, and it was determined that the fire resistance was inferior.
[Composition of aqueous foamable fireproof coating composition (X-7)]
First component 25% zinc acetate aqueous solution 0.65 parts Deionized water 20 parts Melamine 8.09 parts Dipentaerythritol 8.09 parts Titanium oxide 7.94 parts Ammonium polyphosphate 24.27 parts Rock wool fiber 0.5 parts Second component 50% acrylic resin emulsion (note 2) 17.26 parts Carbon black 0.01 parts 2,2,4-trimethylpentanediol monoisobutyrate 5.9 parts Thickener 0.1 parts

Claims (13)

An aqueous intumescent fire-resistant coating composition comprising a resin, a char-forming adjuvant, a carbon source, a foaming agent, and water, wherein the carbon source comprises a polyhydric alcohol phosphate ester , and the polyhydric alcohol phosphate ester is 4-hydroxymethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane 1-oxide . The aqueous foamable fireproof coating composition according to claim 1, wherein the polyhydric alcohol source of the polyhydric alcohol phosphate ester is pentaerythritol. The aqueous foamable fire-resistant coating composition according to claim 1 or 2 , wherein the resin contains a carboxyl group. The aqueous foamable fireproof coating composition according to any one of claims 1 to 3 , wherein the acid value of the resin is 3 to 100 mgKOH/g. The aqueous foamable fireproof coating composition according to any one of claims 1 to 4 , wherein the resin is a copolymer emulsion of a carboxyl group-containing polymerizable unsaturated monomer and another polymerizable unsaturated monomer. 6. The aqueous foamable fireproof coating composition according to claim 5 , wherein the copolymerization amount of the carboxyl group-containing polymerizable unsaturated monomer is within the range of 1 to 10 mass % of the total polymerizable unsaturated monomers. The aqueous foamable fire-resistant coating composition according to any one of claims 1 to 6 , further comprising a crosslinking agent. 8. The aqueous foamable fire-resistant coating composition according to claim 7 , wherein the crosslinking agent is a polyvalent metal compound. The aqueous foamable fire-resistant coating composition according to any one of claims 1 to 8 , which is a one-liquid type coating composition. The aqueous foamable fire-resistant coating composition according to any one of claims 1 to 8 , which is a two-component coating composition. The aqueous foamable fire-resistant coating composition according to claim 10, which is a two-component coating composition to be used by mixing the first component (I) and the second component (II) immediately before use, the first component comprising a resin, the second component comprising a crosslinking agent, and the first component and/or the second component comprising a carbon source, a char-forming auxiliary, a foaming agent and water. A method for coating a substrate, comprising coating a surface of the substrate with the aqueous foamable fireproof coating composition according to any one of claims 1 to 11 . A method for protecting a structure from heat and fire, comprising applying to a surface of a substrate the aqueous intumescent fire-resistant coating composition according to any one of claims 1 to 11 .

Images