JP2020171925A - Film formation method - Google Patents

Abstract

To provide a film formation method which has excellent foaming property and can maintain heat-resistant protection performance of a base material.SOLUTION: A film formation method coats a covering material onto a base material and forms a film, in which the film forms a carbonized heat insulating layer by an increase in a film surface temperature of 200°C or higher, the covering material contains a polyol component (A1) and a polyisocyanate component (A2) as film formation components (A), has a heating residue of 70-98 wt.% and contains polyether polyol (a1) having a molecular weight of 1,000 or more as the polyol component (A1), and the covering material is coated using an air assist type airless spray gun.SELECTED DRAWING: None

Description

The present invention relates to a novel film forming method.

For the purpose of protecting a base material such as a steel material, concrete, wood, or synthetic resin from a fire, various coating materials have been proposed that foam due to a temperature rise in the event of a fire or the like to form a carbonized heat insulating layer. As such a coating material, a synthetic resin mixed with a foaming agent, a carbonizing agent, a flame retardant, or the like is known. The heat resistance protection performance of such a coating material is often determined by the film thickness, and in order to obtain the desired heat resistance protection performance, it is important to apply the coating material so as to be uniform at a predetermined film thickness. Above all, the selection of synthetic resin is important.

For example, as a coating material for thick coating, a coating material in which a flame retardant, a foaming agent, and a carbonizing agent are mixed with a composition composed of a polyol component and a polyisocyanate component has been developed (for example, Patent Document 1).

JP-A-5-70540

However, in the case of Patent Document 1, the expansion ratio of the coating film when the temperature rises is lower than that of the coating material using acrylic resin or epoxy resin as the synthetic resin, and further, the carbonized heat insulating layer (foamed layer) is incinerated or shrunk. There was still room for improvement in order to obtain the desired heat-resistant protection performance. Further, when forming a thick film, the coating workability is inferior, and it may be difficult to form a film having a uniform thickness. The present invention has been made in view of such a problem, and an object of the present invention is to provide a film forming method capable of forming a stable carbonized heat insulating layer when the temperature rises and ensuring excellent heat resistance protection performance. And.

In order to solve such a problem, the present inventors have excellent thick coating property by applying a film forming method for applying a specific coating material to a base material by a specific coating method. The present invention has been completed by finding that it exhibits excellent foamability when the temperature rises due to a fire or the like, forms a carbonized heat insulating layer, and can maintain the heat-resistant protective performance of the base material.

That is, the present invention has the following features.
1. 1. A film forming method in which a coating material is applied to a base material to form a film.
The coating film forms a carbonized heat insulating layer when the coating film surface temperature rises to 200 ° C. or higher .
The coating material contains a polyol component (A1) and a polyisocyanate component (A2) as a film-forming component (A), and has a heating residue of 70 to 98% by weight.
As the polyol component (A1), a polyether polyol (a1) having a molecular weight of 1000 or more is contained.
A method for forming a film, which comprises applying the coating material using an air-assisted airless spray gun.
2. Wherein as the polyol component (A1), 1, characterized in that it comprises the polyether polyol (a1) and a fluorine-containing polyol (a2). The film forming method according to.
3. 3. 1. The fluorine-containing polyol (a2) is contained in an amount of 0.1 to 30% by weight in terms of solid content with respect to the total amount of the polyol component (A1). Or 2. The film forming method according to.

The present invention is a film forming method for applying a specific coating material to a base material, wherein the coating material forms a carbonized heat insulating layer by increasing the temperature, and a film forming component (A). ) Containes a specific polyol component (A1) and a polyisocyanate component (A2), the heating residue is 70 to 98% by weight, and the coating material is applied by using an air-assisted airless spray gun. It is excellent in thick coating property, exhibits excellent foaming property when the temperature rises due to a fire or the like, and can form a carbonized heat insulating layer to enhance the heat resistance protection performance of the base material.

Hereinafter, the present invention will be described in detail based on the embodiments thereof.

The film forming method of the present invention is characterized in that a specific coating material is applied to a base material by a specific method.

(Base material)
Examples of the base material to be the subject of the present invention include structures such as buildings and civil engineering structures, and specifically, various base materials such as walls, columns, floors, beams, roofs, stairs, ceilings, and doors. Examples of such a base material include concrete, mortar, siding board, extruded board, gypsum board, pearlite board, brick, plastic, wood, metal, steel frame (steel material), glass, porcelain tile and the like. These base materials may have a coating film already formed on the surface thereof, have some kind of base treatment (rust prevention treatment, flame retardant treatment, etc.) applied, or have a wallpaper attached. The present invention enhances the heat resistance and aesthetics of the base material, and is particularly the most suitable film forming method for enhancing the heat resistance and aesthetics of a steel frame (steel material).

(Dressing material)
In the present invention, a specific coating material, that is, a coating material in which the coating material forms a carbonized heat insulating layer by a temperature rise (heating) such as a fire (hereinafter, also simply referred to as "coating material") with respect to the substrate surface. ) Is applied. The coating material of the present invention contains a polyol component (A1) and a polyisocyanate component (A2) as essential components as a film-forming component (A). The polyol component (A1) and the polyisocyanate component (A2) are components that react to form a film.

In the present invention, it is preferable that the polyol component (A1) contains the polyether polyol (a1) and the fluorine-containing polyol (a2) in combination. As a result, due to the temperature rise of the coating film (preferably the coating film surface temperature is 200 ° C. or higher, more preferably 250 ° C. or higher), it has excellent foamability and is stable by suppressing ashing and shrinkage of the carbonized heat insulating layer. A carbonized heat insulating layer can be formed to enhance the heat resistance of the base material.

Polyether polyols of the present invention (a1) has a molecular weight of 1000 or more (more preferably 3,000 to 20,000, more preferably 5,000 or more 18000 or less, particularly preferably 6000 or more than 15,000, most preferably 6500 or more 12000 or less) Is. By including such a polyether polyol (a1) as the polyol component (A1), excellent foamability can be obtained by increasing the temperature of the coating film (preferably the coating film surface temperature is 200 ° C. or higher, more preferably 250 ° C. or higher). As shown, the heat resistant protection performance of the base material can be enhanced. In the present invention, the molecular weight of the polyol component (A1) is a number average molecular weight (Mn), which is a so-called polystyrene-equivalent molecular weight determined by gel permeation chromatography using a polystyrene polymer as a reference.

The above-mentioned polyether polyol (a1) is addition polymerization of polyhydric alcohols such as trimethylolpropane, glycerin, hexanetriol, pentaerythritol derivative, sorbitol and neopentyl glycol and alkylene oxides such as ethylene oxide and propylene oxide. Is obtained by. In the present invention, a polymer obtained by addition polymerization of the above polyhydric alcohols with ethylene oxide and / or propylene oxide is preferable, and one having ethylene oxide and / or propylene oxide added to the end is more preferable. is there. Further, the above-mentioned polyether polyol preferably contains a polyether polyol having 3 or more functional groups (3 or more functional groups) having an active hydrogen atom. In this case, the curability is excellent and the film can be stably formed, so that the effect of the present invention can be easily obtained. A hydroxyl group is suitable as the functional group having an active hydrogen atom.

The hydroxyl value of such a polyether polyol (a1) is preferably 3 to 150 mgKOH / g (more preferably 5 to 100 mgKOH / g, still more preferably 7 to 40 mgKOH / g, and most preferably 10 to 30 mgKOH / g). Is. By using such a polyol component (a1), it is possible to exhibit more excellent foamability and enhance the heat-resistant protection performance of the base material. In the present invention, the hydroxyl value is a value (mgKOH / g) represented by the number of mg of potassium hydroxide equimolar to the hydroxyl group contained in 1 g of solid content, and “α to β” is “α or more β”. It is synonymous with "below".

The content of the polyether polyol (a1) is preferably 70 to 99.9% by weight (more preferably 90 to 99% by weight) with respect to the total amount of the polyol component (A1).

In the present invention, by containing the fluorine-containing polyol (a2) as the polyol component (A1), the flame retardancy of the film-forming component (A) is enhanced, and the film is excellent when the temperature rises due to a fire or the like. It exhibits foamability, forms a carbonized heat insulating layer, can suppress ashing and shrinkage even in a high temperature atmosphere, and can enhance the heat resistance protection performance of the base material.

The fluorine-containing polyol (a2) is not particularly limited, but for example, a fluorine-containing monomer such as a fluoroolefin monomer or a fluoroalkyl group-containing acrylic monomer, a hydroxyl group-containing vinyl-based monomer, and other components, if necessary, are used. It is obtained by copolymerizing with a polymerizable monomer. Examples of the fluoroolefin monomer include perfluoroolefins such as tetrafluoroethylene, chlorotrifluoroethylene and hexafluoropropylene, vinyl fluoride and vinylidene fluoride. Examples of the fluoroalkyl group-containing acrylic monomer include perfluoromethyl methacrylate, perfluoroisononyl methyl methacrylate, 2-perfluorooctyl ethyl acrylate, 2-perfluorooctyl ethyl methacrylate, trifluoroethyl acrylate and the like. These can be used alone or in combination of two or more. In the present invention, it is preferable to use one or more selected from tetrafluoroethylene and chlorotrifluoroethylene, and more preferably chlorotrifluoroethylene.

Examples of the hydroxyl group-containing vinyl-based monomer include hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, and hydroxypentyl vinyl ether; ethylene glycol monoallyl ether, diethylene glycol monoallyl ether, and triethylene glycol monoallyl ether. Hydroxyaryl ethers such as 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 4-hydroxyethyl (meth) acrylate, hydroxyl group-containing (meth) acrylate such as 4-hydroxybutyl (meth) acrylate, and the like. And one or more of these can be used.

Examples of other polymerizable monomers include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and 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) (Meta) acrylic acid alkyl ester such as acrylate; Amino such as dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, dimethylamino (meth) acrylate, aminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate Group-containing monomers; 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; (meth) acrylamide, ethyl ( Amid-containing monomer such as meta) acrylamide; nitrile group-containing monomer such as (meth) acrylonitrile; epoxy group-containing monomer such as glycidyl (meth) acrylate; aromatic vinyl monomer such as styrene, methylstyrene, chlorostyrene, vinyltoluene; acetic acid Vinyl esters such as vinyl, vinyl propionate, vinyl butylate, vinyl pivalate; olefin-based monomers such as ethylene and propylene can be mentioned, and one or more of these can be used as needed.

As such a fluorine-containing polyol (a2), the fluorine content in the solid content of the fluorine-containing polyol (a2) is 10 to 50% by weight (more preferably 15 to 40% by weight, still more preferably 20 to 35% by weight). ) Is preferable. Further, the hydroxyl value is preferably 5 to 100 mgKOH / g (more preferably 10 to 80 mgKOH / g). Further, the molecular weight [number average molecular weight (Mn)] is preferably 5000 to 100000 (more preferably 8000 to 60000). By containing such a fluorine-containing polyol (a2), when the temperature rises due to a fire or the like, the film exhibits excellent foamability and forms a carbonized heat insulating layer, and suppresses ashing and shrinkage even in a high temperature atmosphere. It is possible to improve the heat-resistant protection performance of the base material.

The content of the fluorine-containing polyol (a2) is preferably 0.1 to 30% by weight (more preferably 0.5 to 20% by weight, still more preferably 0.5 to 20% by weight) in terms of solid content with respect to the total amount of the polyol component (A1). 1 to 10% by weight). By satisfying this range, the heat-resistant protection performance of the base material can be enhanced, and sufficient adhesion to the topcoat material can be ensured.

（式１）
例えば、イソシアヌル酸トリス（ヒドロキシアルキル）エステル等が使用できる。イソシアヌル酸トリス（ヒドロキシアルキル）エステルとしては、例えば、イソシアヌル酸トリス（２ヒドロキシエチル）、イソシアヌル酸トリス（２ヒドロキシプロピル）、イソシアヌル酸トリス（２ヒドロキシブチル）、イソシアヌル酸トリス（２,３ジヒドロキシプロピル）等のイソシアヌレート環と水酸基を有するアルキルエステルが挙げられる。 Further, in the present invention, it is preferable to include the polyol compound (a3) having an isocyanurate ring as the polyol component (A1). Examples of the polyol compound (a3) having an isocyanurate ring include a compound having an isocyanurate ring (formula 1) and two or more hydroxyl groups.

(Equation 1)
For example, trisocyanuric acid (hydroxyalkyl) ester and the like can be used. Examples of the tris isocyanurate (hydroxyalkyl) ester include tris isocyanurate (2 hydroxyethyl), tris isocyanurate (2 hydroxypropyl), tris isocyanurate (2 hydroxybutyl), and tris isocyanurate (2,3 dihydroxypropyl). Examples thereof include alkyl esters having an isocyanurate ring and a hydroxyl group.

Further, as the polyol compound (a3) having an isocyanurate ring, for example, an acrylic polyol having an isocyanurate ring can also be used. As such a compound, for example, an isocyanuric acid derivative having a reactive functional group selected from a vinyl group, an acryloyl group, a thiol group, an alkoxysilyl group, a carboxyl group, a glycidyl group and the like is reacted at the time of producing an acrylic polyol. Can be obtained by In the reaction here, for example, a combination of a polymerizable unsaturated double bond and a vinyl group, an acryloyl group, or a thiol group, an alkoxysilyl group, a glycidyl group and a carboxyl group, an amino group and a glycidyl group may be used.

The polyol compound (a3) having an isocyanurate ring is preferably 0.01 to 20% by weight (more preferably 0.05 to 15% by weight, still more preferably 0.1 to 10% by weight) in the polyol component (A1). %). As a result, the heat resistance of the cured film of the film-forming component (A) can be further enhanced, and a stable carbonized heat insulating layer can be formed when the temperature rises due to a fire or the like. It has excellent adhesion to and can prevent the carbonized heat insulating layer from falling off.

In addition to the above components (a1), (a2), and (a3), the polyol component (A1) of the present invention includes, for example, polyester polyol, acrylic polyol, epoxy-containing polyol, silicone-containing polyol, castor oil, and castor oil modification. Examples thereof include polyols, polycarbonate polyols, polylactone polyols, polybutadiene polyols, polypentadiene polyols, and one or more selected from these can be used.

Examples of the polyisocyanate component (A2) of the present invention include toluene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (pure-MDI), polypeptide MDI, xylylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), and isophorone. Diisocyanate (IPDI), hydrogenated XDI, hydrogenated MDI, etc., or allophanated, biuretized, dimerized (uretdione), trimerized (isosocyanurate), adducted, carbodiimidated derivatives, etc.; Examples thereof include blocked isocyanate obtained by blocking diisocyanate with alcohols, phenols, ε-caprolactam, oximes, active methylene compounds and the like, and one or more selected from these can be used. The above-mentioned component (a3) is a component different from the above-mentioned component (A2).

In the present invention, it is preferable that the polyisocyanate component (A2) contains hexamethylene diisocyanate (HMDI) and / or a derivative thereof (hereinafter, also referred to as “HMDIs”). The content of the HMDIs is preferably 90% by weight or more (more preferably 95% by weight or more) with respect to the total amount of the polyisocyanate component (A2). Further, it is also preferable that the polyisocyanate component (A2) is composed of only HMDIs. Further, as the derivative, a biuret form and / or an isocyanurate form is suitable. In such a case, the curability of the formed film is excellent, and when the temperature rises, more excellent foamability can be exhibited, and the heat resistance of the base material can be enhanced.

The mixture of the polyol component (A1) and the polyisocyanate component (A2) is preferably 0.6 to 3.5 (more preferably 1 to 1) in terms of the NCO / OH equivalent ratio of the polyol component (A1) and the polyisocyanate component (A2). The ratio is 2.5, more preferably 1.1 to 1.9). In such a case, it is excellent in curability, a uniform film with a desired thickness can be formed, and it has more excellent foamability against a temperature rise due to a fire or the like, and a stable carbonized heat insulating layer is formed. The heat-resistant protection performance of the base material can be improved. Further, the formed film has excellent durability (for example, waterproofness, water permeability, crack resistance, substrate followability, etc.), can maintain the initial appearance (aesthetics) for a long period of time, and is caused by a fire or the like. The effect of the present invention can be sufficiently exerted when the temperature rises or the like.

In the present invention, as the film-forming component (A), in addition to the polyol component (A1) and the polyisocyanate component (A2), isocyanate is a component different from the (a3) component and the (A2) component. A compound (A3) having a nurate ring can also be included. The compound (A3) having an isocyanurate ring is preferably reacted with the polyol component (A1) and / or the polyisocyanate component (A2) to form a film, for example, an alkoxysilyl group, a carboxyl group, or a glycidyl group. Examples thereof include isocyanuric acid derivatives having at least one reactive functional group such as. In this case, as the polyol component (A1) and / or the polyisocyanate component (A2), those having an alkoxysilyl group, a glycidyl group, a carboxyl group, an amino group and the like may be used.

The blending amount of the compound (A3) having an isocyanurate ring is preferably 0.1 to 30 parts by weight (more) than 100 parts by weight of the solid content of the polyol component (A1) and the polyisocyanate component (A2). It is preferably 0.5 to 20 parts by weight, more preferably 1 to 15 parts by weight). In such a case, the effect of the present invention can be fully exerted.

In the present invention, a curing catalyst that promotes the reaction between the polyol component (A1) and the polyisocyanate component (A2) can be used in combination. The curing catalyst is a substance having an action of promoting the reaction of isocyanate groups to cure. Examples of the curing catalyst include various types such as an amine catalyst, an organometallic catalyst, and an inorganic catalyst. For example, examples of the amine-based catalyst include ethylenediamine, triethylenediamine, triethylamine, ethanolamine, diethanolamine, hexamethylenediamine, a derivative thereof, or a mixture with a solvent. Examples of the organometallic catalyst include organometallic compounds such as dibutyltin dilaurate and dibutyltin diacetate; organometallic salts such as potassium acetate, zinc stearate, calcium stearate, lead stearate, aluminum stearate, and tin octylate. Examples of the inorganic catalyst include tin chloride and the like. These can be used alone or in combination of two or more, and can also be mixed with a solvent. In the present invention, it is particularly preferable to include an organometallic catalyst. In this case, it is possible to promote curing and enhance the curability of the film-forming component (A), thereby enhancing the effect of the present invention.

The cured film formed from the film-forming component (A) has an exothermic peak in a differential thermal analysis method (DTA method), and the exothermic peak is in a temperature range of 200 to 400 ° C (more preferably 250 to 380 ° C). It is preferable to have a maximum value of. In such a case, when the temperature rises due to a fire or the like, the foamability is further improved, an excellent carbonized heat insulating layer can be formed, and the heat resistance and protection of the base material can be enhanced.

The mechanism of action is not limited, but for example, the cured film of the film-forming component (A) begins to soften as the temperature rises, and then a decomposition reaction such as a urethane bond proceeds. When the exothermic peak of the cured film of the film-forming component (A) has a maximum value in the above temperature range, the foaming and carbonization reactions can efficiently proceed in a state where the film is softened without much progress of decomposition. Therefore, it is considered that the foamability is improved and the carbonized heat insulating layer can be stably formed. In particular, in the present invention, the film-forming component (A) contains a fluorine-containing polyol as the polyol component (a1), so that the exothermic peak of the cured film can be shifted to the high temperature side. As a result, it is considered that the flame retardancy of the cured film can be enhanced, decomposition at less than 200 ° C. can be suppressed, and the effects of the present invention can be fully exhibited.

In the present invention, the differential thermal analysis method for the cured film of the film-forming component (A) is a measurement of a cured film containing the polyol component (A1) and the polyisocyanate component (A2) as a sample. The differential thermal analysis method was measured using a differential thermal analyzer (for example, "differential thermal balance Thermo plus EVO2 TG-DTA series" manufactured by Rigaku, etc.), and the sample was placed in a platinum sample pan at 3 ± 1 mg. It was measured by using α-alumina as a standard substance and changing the temperature from 100 to 900 ° C. at a heating rate of 20 ° C./min.

Further, in the coating material of the present invention, as components different from the film forming component (A), for example, a foaming agent (B), a carbonizing agent (C), a flame retardant (D), and a filler (E) Etc. can be included.

Examples of the foaming agent (B) include melamine and its derivatives, dicyandiamide and its derivatives, azobistetrasome and its derivatives, azodicarbonamide, urea, thiourea and the like. These can be used alone or in combination of two or more. The content of the foaming agent (B) is preferably 10 to 200 parts by weight (more preferably 20 to 150 parts by weight) with respect to 100 parts by weight of the solid content of the film-forming component (A). The foaming agent (B) of the present invention imparts a foaming action to the coating film due to a temperature rise in the event of a fire or the like. Specifically, when the temperature of the coating film surface is preferably 200 ° C. or higher. It imparts a foaming action.

Examples of the carbonizing agent (C) include pentaerythritol, dipentaerythritol, trimethylolpropane, starch, casein and the like. These can be used alone or in combination of two or more. In the present invention, pentaerythritol and dipentaerythritol are particularly preferable because they are excellent in dehydration cooling effect and carbonized heat insulating layer forming effect. The content of the carbonizing agent (C) is preferably 10 to 200 parts by weight (more preferably 20 to 120 parts by weight) with respect to 100 parts by weight of the solid content of the film-forming component (A). The carbonizing agent (C) of the present invention imparts an action of forming a carbonized heat insulating layer by dehydrating and carbonizing the film-forming component (A) together with carbonization due to a temperature rise in the event of a fire or the like.

Examples of the flame retardant (D) include organophosphorus compounds such as tricresyl phosphate and diphenyl cresyl phosphate; chlorinated polyphenyl, chlorinated polyethylene, diphenyl chloride, triphenyl chloride, chlorinated paraffin, and pentachloride fatty acid. Chlorine compounds such as esters, perchloropentacyclodecane, chlorinated naphthalene, tetrachlorophthalic anhydride; antimony compounds such as antimon trioxide and antimon pentachloride; phosphorus trichloride, phosphorus pentachloride, ammonium phosphate, ammonium polyphosphate, phosphorus Phosphorus compounds such as melamine acid, melamine polyphosphate, melam polyphosphate, melem polyphosphate, boron phosphate, boron polyphosphate, aluminum phosphate, aluminum polyphosphate; and other inorganic compounds such as zinc borate and sodium borate are mentioned. Be done. These can be used alone or in combination of two or more. In the present invention, as the flame retardant (D), for example, melamine polyphosphate, melamine polyphosphate, melamine polyphosphate / melamine / melem double salt, or a composite compound of melamine polyphosphate / melamine / melem double salt and dimerum pyrosulfate, etc. It is preferable to contain at least one or more phosphorus compounds selected from the above, and it is also preferable to contain ammonium polyphosphate in combination with these. The content of the flame retardant (D) is preferably 100 to 1000 parts by weight (more preferably 200 to 800 parts by weight) with respect to 100 parts by weight of the solid content of the film-forming component (A).

Examples of the filler (E) include talc, calcium carbonate, sodium carbonate, aluminum oxide (alumina), titanium oxide, zinc oxide, silica, clay, clay, silas, mica, silica sand, silica stone powder, quartz powder, and barium sulfate. And so on. These can be used alone or in combination of two or more. The content of the filler (E) is preferably 3 to 200 parts by weight (more preferably 5 to 150 parts by weight) with respect to 100 parts by weight of the solid content of the film-forming component (A).

Further, in the present invention, metal hydrate (F), fiber (G) and the like can be included in addition to the above components. The metal hydrate (F) exhibits endothermic property due to a dehydration reaction or the like when the temperature rises, and is different from the filler (E). Examples of such a metal hydrate (F) include aluminum hydroxide and magnesium hydroxide. These can be used alone or in combination of two or more. The average particle size of the metal hydrate (F) is preferably 0.1 to 20 μm (more preferably 0.2 to 15 μm, further preferably 0.3 to 8 μm, and most preferably 0.4 to 3 μm). Is. The content of the metal hydrate (F) is preferably 1 to 200 parts by weight (more preferably 10 to 100 parts by weight, still more preferably 25) with respect to 100 parts by weight of the solid content of the film-forming component (A). ~ 80 parts by weight).

In the present invention, it is preferable to use the filler (E) and the metal hydrate (F) in combination. In this case, the filler (E) and the metal hydrate (F) have a weight ratio of 1: 9 to 9: 1. (More preferably 2: 8 to 8: 2). In this case, foamability, particularly shrinkage of the carbonized heat insulating layer under high temperature can be suppressed, and a stable carbonized heat insulating layer can be formed, so that the effect of the present invention can be enhanced. The average particle size is measured by a laser diffraction type particle size distribution measuring device.

The fiber (G) can enhance the thick coating property and suppress the cracking of the coating film. In addition, the fiber (G) can prevent the coating film from sagging when the temperature rises due to a fire or the like, and can enhance the thermal conductivity inside the coating film. As a result, excellent foamability can be exhibited, a uniform carbonized heat insulating layer can be formed, and the heat resistant protection performance of the base material can be enhanced. Examples of such fibers (G) include acrylic fibers, acetate fibers, aramid fibers, copper ammonia fibers (cupla), nylon fibers, novoloid fibers, pulp fibers, biscous rayon, vinylidene fibers, polyester fibers, polyethylene fibers, and the like. Organic fibers such as polyvinyl chloride fiber, polyclar fiber, bolinosic fiber, polypropylene fiber, cellulose fiber, carbon fiber, rock wool fiber, glass fiber, silica fiber, alumina fiber, silica-alumina fiber, slag wool fiber, ceramic fiber, carbon Examples thereof include fibers and inorganic fibers such as silicon carbide fibers. These can be used alone or in combination of two or more.

In the present invention, it is preferable that the fiber (G) contains an inorganic fiber, and among them, artificial mineral fibers such as rock wool fiber, slag wool fiber, glass fiber and ceramic fiber are preferable. As a result, cracking of the coating film can be further suppressed. Further, when the temperature rises due to a fire or the like, it is possible to prevent the coating film from sagging and the like, and it is possible to further enhance the thermal conductivity inside the coating film. As a result, it is possible to form a carbonized heat insulating layer that uniformly exhibits excellent foamability up to the inside of the coating film (core portion) and has more uniform and excellent strength, and further enhances the heat resistance protection performance of the base material.

The size of the fiber (G) (fiber length and fiber diameter) may be set according to the performance of the coating material, the applicable base material, the coating tool, and the like, and the average fiber length is preferably 10 to 10. It is preferably in the range of 1000 μm (more preferably 15 to 800 μm, still more preferably 20 to 600 μm) and the average fiber diameter is preferably in the range of 0.5 to 10 μm (more preferably 1 to 8 μm). The aspect ratio (fiber length / fiber diameter) is preferably 3 to 300 (more preferably 5 to 200). When the above range is satisfied, the thick coating property is enhanced, the formed film is less likely to crack, and when the temperature rises due to a fire or the like, the film is less likely to sag, and a stable carbonized heat insulating layer can be provided. Can be formed. The content of the fiber (G) is preferably 0.5 to 30 parts by weight (more preferably 1 to 25 parts by weight, still more preferably 2 to 2) with respect to 100 parts by weight of the solid content of the film-forming component (A). 20 parts by weight).

The coating material of the present invention preferably further contains a high boiling point compound (H). The high boiling point compound (H) is a liquid at 20 ° C. and is a high boiling point liquid compound having a boiling point of 100 ° C. or higher (more preferably 150 ° C. or higher, still more preferably 200 ° C. or higher). By including such a high boiling point compound (H), the dispersion stability of the powder components such as the component (B) to the component (G) can be improved. In addition, a good film having excellent adhesion can be formed, and in particular, the elasticity of the film can be improved to prevent the film from cracking. Further, when the coating film is exposed to a high temperature due to a fire or the like, it contributes to appropriate softening of the coating film, further enhances the foamability, suppresses the formed carbonized heat insulating layer from falling off (peeling), etc. Heat resistance protection performance can be improved.

The high boiling point compound (H) is not particularly limited as long as it satisfies the above conditions, and for example, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, dihexyl phthalate, di-2-ethylhexyl phthalate. , Phthalate compounds such as diisononyl phthalate, diisodecyl phthalate, diundecyl phthalate, butylbenzyl phthalate; diethyl adipate, dibutyl adipate, diisobutyl adipate, dihexyl adipate, di-2-ethylhexyl adipate, adipate Alibo dibasic acid ester compounds such as dioctyl, diisononyl adipate, diisodecyl adipate, bis (butyl diglycol) adipate, diethyl sebacate, dibutyl sebacate, dihexyl sebacate, di-2-ethylhexyl sebacate; adipic acid Adipic acid-based polyesters such as -1,3 butylene glycol-based polyester and -1,2 propylene glycol-based polyester; dimethyl maleate, diethyl maleate, dibutyl maleate, dihexyl maleate, di-2-ethylhexyl maleate, Maleic acid ester compounds such as diisononyl maleate and diisodecyl maleate; triethyl phosphate, tributyl phosphate, tri-2-ethylhexyl phosphate, tricredyl phosphate, trixylenyl phosphate, cresyldiphenyl phosphate, -2 ethylhexyl diphenyl phosphate Phthalate compounds such as;

Trimethic acid ester compounds such as tris-2-ethylhexyl trimerite; ricinoleic acid ester compounds such as methylacetyl lysinolate; di-2-ethylhexyl epoxyhexahydrophthalate, diepoxystearyl epoxyhexahydrophthalate, butyl epoxidized fatty acid, Epoxy ester compounds such as epoxidized fatty acid 2-ethylhexyl, epoxidized soybean oil, and epoxidized flaxseed oil; benzoic acid ester compounds such as benzoic acid glycol ester; 1-phenyl-1-xylylethane, 1-phenyl-1-ethyl Examples thereof include aromatic hydrocarbon compounds such as phenylethane, lactones such as γ-butyrolactone, and mixtures of petroleum resin (aromatic hydrocarbon distillate polymer having 8 to 10 carbon atoms) and styrylxylene. These can be used alone or in combination of two or more.

In the present invention, the high boiling point compound (H) preferably contains at least one selected from a phthalate ester compound, an aliphatic dibasic acid ester compound, and a phosphoric acid ester compound, and further, the number of carbon atoms of the alkyl group is high. It is preferable to contain one or more selected from 4 to 11 (more preferably 5 to 10, more preferably 6 to 9) phthalate compounds and aliphatic dibasic acid ester compounds. As specific examples thereof, for example, diisononyl phthalate, diisononyl adipate and the like are suitable.

The content of the high boiling point compound (H) is preferably 5 to 150 parts by weight (more preferably 10 to 100 parts by weight, still more preferably 15 to 100 parts by weight) with respect to 100 parts by weight of the solid content of the film-forming component (A). 80 parts by weight). When the above range is satisfied, the dispersibility of the powder component is enhanced, the thick coating property is excellent, the foaming property is excellent when the temperature rises due to a fire or the like, and the effect of maintaining the heat resistance protection performance of the base material is maintained. Can be fully demonstrated. Furthermore, excellent topcoat material suitability can be obtained.

In addition, the additive may be any additive that does not significantly impair the effects of the present invention, for example, pigments, wetting agents, plasticizing agents, lubricants, preservatives, fungicides, algae-proofing agents, antibacterial agents, and thickeners. , Leveling agent, dispersant, defoaming agent, cross-linking agent, silane coupling agent, ultraviolet absorber, light stabilizer, antioxidant, halogen trapping agent, diluting solvent and the like.

Among these, examples of the antioxidant include phosphorus-based, sulfur-based, and hindered-type phenol-based antioxidants. These can be used alone or in combination of two or more. By including such an antioxidant, deterioration of the coating film can be suppressed not only in normal times but also when the temperature rises due to a fire or the like, and the properties of the carbonized heat insulating layer formed by the temperature rise can be improved. ..

The present invention is characterized in that the heating residue of the coating material is 70 to 98% by weight (preferably 75 to 95% by weight, more preferably 80 to 93% by weight). If the heating residue of the coating material is less than the above lower limit value, excessive coating or the like is required to obtain a desired film thickness, which is troublesome. In addition, there is a possibility that a sufficient film thickness cannot be secured, and the heat resistance may be inferior. On the other hand, if the above upper limit value is exceeded, the film-forming property is lowered (adhesion is lowered), and heat resistance protection may not be sufficiently obtained. The heating residue of the coating material is a value measured by the method of JIS K 5601-1-2, and the heating temperature is 105 ° C. and the heating time is 60 minutes).

Further, in the present invention, the viscosity of the coating material is preferably 5 to 70 Pa · s (more preferably 7 to 60 Pa · s, further preferably 10 to 50 Pa · s, and particularly preferably 15 to 40 Pa · s). When the viscosity of the coating material satisfies the above range, it is excellent in coating workability and thick coating property, and a uniform coating can be formed. As a result, sufficient heat resistance can be obtained. The viscosity of the coating material is the viscosity at 20 rpm measured with a BH type viscometer immediately after the coating material is prepared (in the case of the two-component type, after mixing the main agent and the curing agent) at a temperature of 23 ° C. Guideline value).

In the present invention, by applying a coating material satisfying the range of the above-mentioned heating residue (preferably the above-mentioned heating residue and viscosity) to form a film, the film can be thickened, which is good for the substrate. It exhibits adhesion and can stably form a uniform film. Further, the formed film exhibits excellent foamability when the temperature rises due to a fire or the like, and can form a carbonized heat insulating layer to maintain the heat resistant protection performance of the base material.

The coating material of the present invention is preferably a two-component coating material having a main agent containing the polyol component (a1) and a curing agent containing the polyisocyanate component (a2). That is, the main agent and the curing agent may be stored in separate packages at the time of distribution, and these may be mixed at the time of use (at the time of application). In this case, the foaming agent (B), the carbonizing agent (C), the flame retardant (D), and the filler (E) (furthermore, the metal hydrate (F), the fiber (G), high The boiling point compound (H) and the curing catalyst) may be mixed with at least one of the main agent and the curing agent, respectively, but in the present invention, they are preferably mixed with the main agent. In addition, each component can be added when the main agent and the curing agent are mixed.

(Film formation method)
The film forming method of the present invention is to apply the coating material to a base material to form a film, and is characterized by applying the coating material using an air-assisted airless spray gun. To do. The air-assisted airless spray gun injects a liquid coating material from the injection port under relatively high pressure to atomize the coating material, and assists compressed air from the outside to the atomized mist. It is an airless spray gun that adjusts the spread of fog by ejecting it. Such an air assist type airless spray gun is not particularly limited, but is, for example, an air coat gun (for example, "GM4700AC", "GM4100AC" manufactured by WAGNER), an air curtain gun (for example, manufactured by Seiwa Sangyo Co., Ltd.). "ACG-3T" etc.), air assist gun (for example, "G15", "G40" manufactured by GRACO, "AA1600M" manufactured by BINKS, etc.) and the like can be used.

In the present invention, for example, an airless coating machine is used to apply a high pressure to the coating material, and the air-assisted airless spray gun is used for coating. In this case, the pressure of the airless coating machine is preferably 10 to 40 MPa (more preferably 15 to 35 MPa, further preferably 18 to 33 MPa), and the air pressure supplied to the air assist type airless spray gun is preferably 0. It is 1 to 2 MPa (more preferably 0.3 to 0.9 MPa). By applying under such conditions, even a coating material having a high solid content such as the above-mentioned coating material can be stably atomized, and at the same time, it exhibits good mist spreadability and is uniform. A film can be formed. At the same time, it is possible to prevent the mist from spreading too much, so that the coating material is excellent in coating efficiency, loss due to scattering is unlikely to occur, and a thick film can be formed with a small number of coating steps. Further, these coating steps can be performed using a known airless coating machine and a compressor, and there is no need to heat the coating material or the like, and the temperature is (preferably 0 to 45 ° C., more preferably 0 to 45 ° C.). Since it can be performed at 5 to 40 ° C.), it is excellent in workability, work environment, and the like.

When the coating material of the present invention is applied to a base material, it may be applied by applying one step or several steps repeatedly by the above method, but the dry film thickness per step is preferably 400 μm or more (more preferably). It is preferable to apply the coating so as to have a thickness of 500 to 5000 μm). The film thickness to be finally formed may be appropriately set according to the desired functionality, application site, etc., but is preferably about 0.4 to 5 mm. Further, the coating material of the present invention is excellent in curability because it forms a film by the reaction of the above-mentioned component (A1) and the above-mentioned (A2) component, and the drying thereof is preferably at room temperature and the interval to the next step is It may be preferably carried out in 5 hours or more (more preferably 10 hours or more and 30 days or less).

(Undercoat material)
Further, in the present invention, if necessary, the base material can be surface-treated or the undercoat material can be applied before the coating material is applied. As a result, it is possible to improve the adhesion to the base material, the corrosion resistance (rust prevention), and the like. As the surface treatment of the base material, for example, surface treatment with a solvent, acid or the like, scraping with a disc sander, wire foil, scraper, wire brush, sandpaper or the like can be performed.

As the undercoat material, for example, a sealer, a primer, a base conditioner, a surfacer, a putty, and the like, as well as a flat type paint can be applied. These may be either a clear type or a colored type. Further, it may be either water-based or solvent-based, and can be appropriately selected depending on the coating location and the like, and one type or two or more types can be used. The undercoat material preferably contains, for example, a resin component such as an acrylic resin, a urethane resin, or an epoxy resin, and in addition to the above resin components, various additives are blended to such an extent that the effects of the present invention are not affected. Is possible. Examples of such additives include rust preventive pigments, extender pigments, coloring pigments, plasticizers, preservatives, fungicides, algae repellents, defoamers, leveling agents, pigment dispersants, sedimentation inhibitors, and drips. Examples include inhibitor, antioxidant, catalyst, cross-linking agent and the like.

The undercoat material can be applied by using various methods such as brush coating, roller coating, and spray coating. The coating amount is preferably 30 to 500 g / m ² (more preferably 50 to 300 g / m ² ). The number of times the undercoat material is applied may be appropriately set depending on the surface condition of the base material and the like, but is preferably 1 to 2 times.

(Topcoat material)
According to the present invention, the finishing material layer can be laminated on the coating material layer (coating) formed by the covering material. Such a finishing material layer is not particularly limited as long as the covering material layer does not foam when the temperature rises due to a fire or the like and does not hinder the formation of a carbonized heat insulating layer, and is a known finishing material. Can be laminated. Such a finishing material layer can be laminated by applying a topcoat material or by adhering various sheet materials.

As the topcoat material, any of clear type or colored type, glossy type or matte type, hard type or elastic type, thin film type or thick film type can be used. Further, it may be either water-based or solvent-based, and can be appropriately selected according to a desired purpose. Further, the topcoat material of the present invention preferably contains a resin component. Examples of such a resin form include a solvent-soluble resin, a non-aqueous dispersion resin, a solvent-free resin, an aqueous dispersion resin, and a water-soluble resin. Examples of the type of resin include acrylic resin, urethane resin, epoxy resin, vinyl chloride resin, vinyl acetate resin, acrylic silicon resin, fluororesin, silicon resin, polyvinyl alcohol, cellulose derivative, etc., or a composite thereof. Be done. These can be used alone or in combination of two or more. In the present invention, it is particularly preferable to contain one or more selected from urethane resin, epoxy resin, acrylic resin, and acrylic silicone resin.

Further, the resin component may have a cross-linking reactivity. When the resin component is a cross-linking reaction type resin, the water resistance, durability, and adhesion of the formed film are enhanced, and it is possible to suppress the occurrence of swelling / peeling of the film due to rainfall, dew condensation, etc. and the deterioration of heat resistance performance. .. Such a cross-linking reaction type resin may be either one that causes a cross-linking reaction by itself or one that causes a cross-linking reaction by a separately mixed cross-linking agent. Such cross-linking reactivity includes, for example, hydroxyl group and isocyanate group, carbonyl group and hydrazide group, epoxy group and amino group, ald group and semicarbazide group, keto group and semicarbazide group, alkoxyl group, carboxyl group and metal ion, carboxyl. It can be imparted by combining a reactive functional group such as a group and a carbodiimide group, a carboxyl group and an epoxy group, a carboxyl group and an aziridine group, and a carboxyl group and an oxazoline group. Among these, it is preferable to include one or more cross-linking reaction type resins selected from a hydroxyl group-isociate group, a carbonyl group and a hydrazide group, and an epoxy group and an amino group.

As a component other than the resin component of the topcoat material, for example, a coloring pigment, an extender pigment, an aggregate and the like can be mixed. By appropriately blending such components, a desired color and texture can be expressed. The mixing amount of the coloring pigment, the extender pigment, the aggregate, etc. is not particularly limited as long as it does not impair the effects of the coating material (foaming property, heat protection property, etc.), but is preferably 100 parts by weight of the solid content of the resin component. On the other hand, it is preferably 1 to 2000 parts by weight (more preferably 5 to 1000 parts by weight).

In the present invention, it is particularly preferable to use a pigment having infrared reflection and / or infrared transmission as the coloring pigment and the extender pigment. Thereby, the effect such as heat resistance protection can be further enhanced.

Examples of pigments having infrared reflectivity include aluminum flakes, titanium oxide, barium sulfate, zinc oxide, iron oxide, calcium carbonate, silicon oxide, magnesium oxide, zirconium oxide, yttrium oxide, indium oxide, alumina, and iron-chromium composite. Oxides, manganese-bismuth composite oxides, manganese-ittrium composite oxides, black iron oxide, iron-manganese composite oxides, iron-copper-manganese composite oxides, iron-chromium-cobalt composite oxides, copper-chromium composites Examples thereof include oxides, copper-manganese-chromium composite oxides, and one or more of these can be used.

Pigments with infrared transparency include, for example, perylene pigments, azo pigments, yellow lead, titanium red, cadmium red, quinacridone red, isoindolinone, benzimidazolone, phthalocyanine green, phthalocyanine blue, cobalt blue, induslen blue, and ultramarine blue. , Navy blue, etc., and one or more of these can be used.

Further, the topcoat material can also be blended with various additives that can be used in ordinary paints. Examples of such additives include thickeners, film-forming aids, leveling agents, wetting agents, plasticizers, antifreeze agents, pH regulators, preservatives, fungicides, algae-proofing agents, antibacterial agents, and dispersions. Examples thereof include agents, antifoaming agents, adsorbents, ultraviolet absorbers, light stabilizers, antioxidants, fibers, low pollutants, hydrophilic agents, water repellents, coupling agents, catalysts and the like.

In the film forming method of the present invention, the topcoat material may be applied by being applied repeatedly, or two or more kinds of topcoat materials may be laminated and applied. When two or more types of topcoat materials are laminated, one or more types (particularly preferably urethane resin, epoxy) selected from urethane resin, epoxy resin, acrylic resin, and acrylic silicon resin as the first topcoat material (intermediate coating material). It is preferable to contain a resin component (resin, etc.). As a result, the adhesion between the layers of the coating material and the topcoat material can be further improved. Furthermore, it is possible to form a topcoat material film having excellent film physical properties.

The topcoat material may be applied by a known coating method, and can be applied by using various methods such as brush coating, roller coating, and spray coating. The coating amount is preferably 30 to 5000 g / m ² (more preferably 50 to 3000 g / m ² ). The number of times the topcoat material is applied may be appropriately set depending on the surface condition of the base material and the like, but is preferably 1 to 2 times. Further, drying may be preferably performed at room temperature.

Examples of the sheet material include decorative films, decorative sheets, sheet building materials, wallpaper and the like. The thickness thereof is preferably 0.01 to 30 mm (more preferably 0.05 to 20 mm). These may be attached via a known adhesive (adhesive) or the like.

Examples will be shown below to further clarify the features of the present invention. However, the present invention is not limited to this range.

The following materials were used as each raw material.

-Film forming component (A)
・ Polyol component (A1)
The polio ether polyol (a1), the fluorine-containing polyol (a2), and the polyol compound (a3) having an isocyanurate ring are mixed in the weight ratio shown in Table 1 and combined with the polyol components (A1-1) to (A1-13). did.

-Polyether polyol (a1)
(A1-1): Polyether polyol (polymer of ethylene oxide and propylene oxide using glycerin as an initiator, number average molecular weight 10000, number of functional groups 3, hydroxyl value 17 mgKOH / g, addition of terminal ethylene oxide)
(A1-2): Polyether polyol (polymer of ethylene oxide and propylene oxide using glycerin as an initiator, number average molecular weight 7000, number of functional groups 3, hydroxyl value 24 mgKOH / g, addition of terminal ethylene oxide)
(A1-3) Polyether polyol (polymer of ethylene oxide and propylene oxide using glycerin as an initiator, number average molecular weight 6000, number of functional groups 3, hydroxyl value 28 mgKOH / g, addition of terminal ethylene oxide)
(A1-4): Polyether polyol (polymer of ethylene oxide and propylene oxide using propylene glycol as an initiator, number average molecular weight 5100, number of functional groups 3, hydroxyl value 33 mgKOH / g, addition of terminal ethylene oxide)
(A1-5): Polyether polyol (polymer with propylene oxide using glycerin as an initiator, number average molecular weight 4000, number of functional groups 3, hydroxyl value 43 mgKOH / g, addition of terminal propylene oxide)
(A1-6): Polyether polyol (polymer with propylene oxide using glycerin as an initiator, number average molecular weight 700, number of functional groups 3, hydroxyl value 225 mgKOH / g, addition of terminal propylene oxide)

-Fluorine-containing polyol (a2)
(A2-1): Ethylene trifluoride copolymer (chlorotrifluoroethylene-vinyl ether-hydroxyalkyl vinyl tether copolymer, fluorine content 27% by weight, hydroxyl value 52 mgKOH / g, solid content 60% by weight, aromatic Contains hydrocarbon solvent)
(A2-2): Tetrafluoroethylene copolymer (tetrafluoroethylene-vinyl ether-hydroxyalkyl vinyl tether copolymer, fluorine content 36% by weight, hydroxyl value 60 mgKOH / g, solid content 60% by weight, butyl acetate solvent Contains)
-A polyol compound having an isocyanurate ring (a3)
(A3-1) Trichloroisocyanurate (2 hydroxyethyl) (hydroxyl value 645 mgKOH / g)

-Polyisocyanate component (A2)
(A2-1) Biuret-type hexamethylene diisocyanate (NCO content 23.5%)
(A2-2) Isocyanurate-type hexamethylene diisocyanate (NCO content 23.1%)

-Effervescent agent (B): Melamine-Carbide (C): Pentaerythritol-Flame retardant (D1): Ammonium polyphosphate-Flame retardant (D2): Melamine polyphosphate-Melam-Melem double salt-filler (E) : Titanium oxide / metal hydrate (F): Aluminum hydroxide (average particle size: 1 μm)
-Fiber (G): Rock wool fiber (average fiber length 125 μm, average fiber diameter 4.5 μm)
High boiling point compound (H): diisononyl phthalate (boiling point 420 ° C)
-Curing catalyst (I): Organometallic catalyst-Additive 1: Dispersant, defoamer, etc.-Additive 2: Plasticizer, diluting solvent, etc.

(Coating material 1-23)
According to the formulation shown in Table 2, the components (A1), components (B) to (I), and additives 1 and 2 were mixed by a conventional method to prepare a main agent. Next, the component (A2) was mixed to obtain coating materials 1 to 23. In Table 2, the mixing amounts of the components (B) to (I) and the additives 1 and 2 are shown in parts by weight with respect to 100 parts by weight of the solid content of the component (A).

(Examples 1 to 4, Comparative Example 1)
A coating material is applied to the entire surface of the base material (pre-rust-prevented plywood: length 900 mm x width 900 mm x thickness 6 mm) under the following conditions (dry film thickness 1.5 mm), and at room temperature (25 ° C) for 7 days. The cured product was used as a test body, and the following evaluation was carried out.
-Coating conditions [I] Painting at room temperature (25 ° C) using an airless coating machine (pressure 20 to 21 MPa) and an air assist type airless spray gun (supply air pressure: 0.3 MPa).
[II] Painting at room temperature (25 ° C.) using an airless coating machine (pressure 20 to 21 MPa) and an air assist type airless spray gun (supply air pressure: 0.5 MPa).
[III] Painting at room temperature (25 ° C.) using an airless coating machine (pressure 15 to 17 MPa) and an air assist type airless spray gun (supply air pressure: 0.5 MPa).
[IV] Painting at room temperature (25 ° C.) using an airless coating machine (pressure 10 to 13 MPa) and an air assist type airless spray gun (supply air pressure: 0.5 MPa).
[V] Painting at room temperature (25 ° C) using an airless coating machine (pressure 15-18 MPa) and an airless spray gun (supply air: none).

<Painting workability evaluation>
The atomization status of the covering material and the coating stability at the time of preparing the test piece were evaluated. The evaluation criteria are as follows. The results are shown in Table 3.
A: The coating material was well atomized and uniform coating was possible.
B: The coating material was well atomized, and almost uniform coating was possible.
C: The atomization of the covering material was slightly insufficient, and some coating unevenness (tail) occurred.
D: The coating material was not sufficiently atomized.

(Test Examples 1 to 23)
A coating material is applied to the entire surface of a steel sheet (length 150 mm × width 70 mm × thickness 1.6 mm) that has been preliminarily rust-prevented under the application condition [I] (dry film thickness 1.5 mm), and at room temperature (25 ° C). The test piece was cured for 7 days, and the following evaluation was carried out.
<Heat resistance evaluation 1>
Based on the ISO 5660-1 cone calorimeter method, the foaming magnification and the temperature of the back surface of the steel sheet when radiant heat of 50 kW / m ² is radiated to the surface of the test piece for 15 minutes using an electric heater (CONEIII, manufactured by Toyo Seiki Co., Ltd.). Was measured. Each evaluation standard is as follows. The results are shown in Tables 4 and 5.
(Expansion magnification)
AA: Foaming magnification over 35 times A: Foaming magnification over 25 times over 35 times B: Foaming magnification over 20 times over 25 times C: Foaming magnification over 15 times over 20 times D: Foaming magnification 15 times or less (back surface temperature)
AA: Less than 430 ° C A: 430 ° C or more and less than 470 ° C B: 470 ° C or more and less than 500 ° C C: 500 ° C or more and less than 550 ° C D: More than 550 ° C

<Heat resistance evaluation 2>
Based on the ISO 5660-1 cone calorimeter method, using an electric heater (CONEIII, manufactured by Toyo Seiki Co., Ltd.), the foaming ratio when radiant heat of 50 kW / m ² is radiated to the surface of the specimen for 30 minutes, and the temperature of the back surface of the steel sheet Was measured, and the density and incineration were further evaluated. The evaluation criteria for the expansion ratio and the temperature on the back surface of the steel sheet are the same as those for the heat resistance evaluation 1. The criteria for evaluating the density and incineration are as follows. The results are shown in Tables 3 and 4.

(Evaluation of precision)
The test piece whose foaming ratio was measured was cut, and the denseness of the carbonized heat insulating layer in the cross section was visually confirmed. The evaluation criteria were four-grade evaluation (excellent: A>B>C> D: inferior), with high precision being "A" and low precision being "D".
(Evaluation of incineration)
In the above heat resistance evaluation 2, the cross section of the carbonized heat insulating layer formed after radiating radiant heat for 30 minutes was confirmed, and the ratio of the ashed (white) portion was calculated. The evaluation criteria were a four-stage evaluation (excellent: A>B>C> D: inferior), with less ashing being "A" and more ashing being "D".

In Test Examples 1 to 10 and 14 to 22, in both the heat resistance evaluation 1 and the heat resistance evaluation 2 (under a high temperature in which the heating test is extended), the foaming property is excellent, a carbonized heat insulating layer is stably formed, and further. Was able to suppress the shrinkage of the carbonized heat insulating layer, and was able to exhibit sufficient heat resistance protection performance. In particular, in Test Examples 14 to 22, when the heating test was extended, the shrinkage of the carbonized heat insulating layer was sufficiently suppressed (the change in the foaming ratio was small), and even more excellent heat resistance protection performance could be exhibited. .. In Test Example 23, the foamability was insufficient, and further, when the heating test was extended, the shrinkage of the carbonized heat insulating layer was remarkable.

Next, in Test Examples 1 to 4, 7, 8, 14 to 22, which showed excellent foamability in heat resistance evaluations 1 and 2, the following evaluations were carried out.
<Heat resistance evaluation 3>
(Evaluation of dropout prevention)
The covering material of the test piece is horizontally installed so as to be on the lower side, a heater (heater temperature 680 ° C.) is installed at a position 25 mm above the test piece, the test piece is heated by the heater, and the covering material is removed from the steel plate. The temperature of the steel sheet when it fell off was measured. The evaluation was performed in the following four stages. The results are shown in Tables 4 and 5.
A: Dropping temperature 250 ° C or higher B: Dropping temperature 220 ° C or higher and lower than 250 ° C C: Dropping temperature 200 ° C or higher and lower than 220 ° C D: Dropping temperature less than 200 ° C

Further, the following evaluations were carried out on the covering materials 14 to 22.
<Thickening evaluation 1>
A coating material was applied to the entire surface of a pre-rust-prevented steel sheet (length 150 mm x width 70 mm x thickness 1.6 mm) with a film applicator at a wet film thickness of 3 mm, and then at room temperature (25 ° C) for 24 hours, and then at 50 ° C. After curing for 24 hours, the dry film thickness was measured and the change in film thickness was confirmed. The evaluation criteria are as follows.
A: Film thickness reduction rate is less than 15% B: Film thickness reduction rate is 15% or more and less than 30% C: Film thickness reduction rate is 30% or more and less than 45% D: Film thickness reduction rate is 45% or more

<Thickening evaluation 2>
In the thickening evaluation 1, the state of the formed film was visually confirmed. The evaluation criteria were a four-stage evaluation (excellent: A>B>C> D: inferior) in which a uniform film was formed as "A" and a film with cracks was evaluated as "D". The results are shown in Table 4.

Claims (3)

A film forming method in which a coating material is applied to a base material to form a film.
The coating film forms a carbonized heat insulating layer when the coating film surface temperature rises to 200 ° C. or higher .
The coating material contains a polyol component (A1) and a polyisocyanate component (A2) as a film-forming component (A), and has a heating residue of 70 to 98% by weight.
As the polyol component (A1), a polyether polyol (a1) having a molecular weight of 1000 or more is contained.
A method for forming a film, which comprises applying the coating material using an air-assisted airless spray gun. Wherein as the polyol component (A1), the film forming method according to claim 1, characterized in that it comprises the polyether polyol (a1) and a fluorine-containing polyol (a2). The film forming method according to claim 1 or 2, wherein the fluorine-containing polyol (a2) is contained in an amount of 0.1 to 30% by weight in terms of solid content with respect to the total amount of the polyol component (A1). ..