JP6811280B2 - Film formation method - Google Patents

Description

The present invention relates to a novel film forming method.

For the purpose of protecting a base material such as steel, concrete, wood, or synthetic resin from a fire, various foamable coating materials that foam due to a temperature rise at the time of a fire to form a carbonized heat insulating layer have been proposed. As such a foamable coating material, one in which a foaming agent, a carbonizing agent, a flame retardant or the like is blended with a synthetic resin is known. The heat-resistant protection performance of such a coating material is often determined by the coating thickness of the coating material, and in order to obtain the desired heat-resistant protection performance, the coating material should be applied so as to be uniform with a predetermined coating thickness. Is important, and above all, the selection of synthetic resin is important.

For example, as a foaming coating material for thick coating, a foaming 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 foaming ratio is lower than that of a coating material using an acrylic resin or an epoxy resin as a synthetic resin, and the desired heat-resistant protective performance may not be obtained, and there is still room for improvement. It was.

In order to solve such a problem, the present inventors have excellent foaming of a specific polyol composition and a coating material containing a polyisocyanate component, which are excellent in thick coating property and when the temperature rises due to a fire or the like. The present invention has been completed by finding that it has properties 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 as the temperature rises.
The temperature rise of the coating film is 250 ° C. or higher.
The coating material contains a film-forming component (A) and a powder component (B), has a viscosity of 3 to 70 Pa · s, and has a heating residue of 70 to 98% by weight.
The film-forming component (A) contains a polyol component (a1) and a polyisocyanate component (a2).
It said polyol component (a1) has a molecular weight seen contains more than 1000 polyether polyol,
A film forming method comprising a foaming agent (b1) and a carbonizing agent (b2) as the powder component (B) .
2. 2. The coating material is applied by applying it in one or several steps.
The dry film thickness per step is 400 μm or more. The film forming method according to.

The present invention is a coating method for forming a coating by applying a coating material to a substrate, and the coating forms a carbonized heat insulating layer by increasing the temperature. The coating material contains a specific film-forming component (A) and a powder component (B), has a viscosity of 3 to 70 Pa · s, and has a heating residue of 70 to 98% by weight, so that it is excellent in thick coating property and fires. When the temperature rises due to such factors, it has excellent foaming properties, exhibits heat resistance protection performance, and can enhance heat resistance protection of the base material.

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

(Coating material)
The coating material of the present invention contains a film-forming component (A) and a powder component (B), and the film forms a carbonized heat insulating layer due to a temperature rise (heating) such as a fire. The present invention is characterized in that the viscosity of the coating material is 3 to 70 Pa · s (preferably 5 to 60 Pa · s, more preferably 7 to 50 Pa · s, still more preferably 10 to 40 Pa · s). If the viscosity of the coating material is less than the above lower limit value, sagging may occur, and excessive coating or the like may be required to obtain a desired film thickness, which is troublesome. On the other hand, if it exceeds the above upper limit value, the coating workability is lowered, and as a result, a uniform film is not formed, and heat resistance protection may not be sufficiently obtained. The viscosity of the coating material is the viscosity at 20 rpm measured with a BH type viscometer at a temperature of 23 ° C. immediately after the coating material is prepared (in the case of the two-component type, after mixing the main agent and the curing agent) (fifth rotation). Guideline value).

Further, 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 covering 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).

In the present invention, by applying a coating material satisfying the above-mentioned viscosity and heating residue range to form a film, the film can be thickened, and a uniform film can be obtained by showing good adhesion to the substrate. It can be formed stably. 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 film-forming component (A) of the present invention contains a polyol component (a1) and a polyisocyanate component (a2) as essential components. The polyol component (a1) and the polyisocyanate component (a2) are components that react to form a film.

The polyol component (a1) of the present invention contains a polyether polyol (a1') and has a molecular weight of 1000 or more (preferably 3000 or more and 20000 or less, more preferably 5000 or more and 18000 or less, still more preferably 6000 or more and 15000 or less, most. It is preferably 6500 or more and 12000 or less). By using such a polyol component (a1), it has excellent foamability due to an increase in the temperature of the coating film (preferably the coating film surface temperature is 200 ° C. or higher, more preferably 250 ° C. or higher), and the heat resistance of the base material is high. The protection performance can be improved. In the present invention, the molecular weight of the polyol component 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 added with polyhydric alcohols such as trimethylolpropane, glycerin, hexanetriol, pentaerythritol derivative, sorbitol and neopentyl glycol and alkylene oxides such as ethylene oxide and propylene oxide. It is obtained by polymerization. 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.

As such a polyether polyol (a1'), the hydroxyl value 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. ). 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, "α to β" is synonymous with "α or more and β or less".

The content of the polyether polyol (a1') is preferably 90% by weight or more (more preferably 95% by weight or more) with respect to the total amount of the polyol component (a1). Further, it is also preferable that the polyol component (a1) is only a polyether polyol (a1'). Examples of the polyol component other than the above-mentioned polyether polyol (a1') include polyester polyol, castor oil, castor oil-modified polyol, epoxy-modified polyol, silicone-modified polyol, fluorine-modified polyol, acrylic polyol, polycarbonate polyol, polylactone polyol, and the like. Examples thereof include polybutadiene polyol and polypentadiene polyol.

The polyol component is preferably liquid at 20 ° C., and each has a viscosity of 0.05 to 10 Pa · s (more preferably 0.1 to 5.0 Pa · s). Thereby, the effect of the present invention can be easily obtained. The viscosity of the polyol composition is the viscosity at 20 rpm (the needle limit value at the fifth rotation) measured by a BH type viscometer at a temperature of 23 ° C.

Examples of the polyisocyanate component (a2) that reacts with the polyol composition to form a film include toluene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (pure-MDI), polypeptide MDI, and xylylene diisocyanate (XDI). , Hexamethylene diisocyanate (HMDI), Isophorone diisocyanate (IPDI), hydrogenated XDI, hydrogenated MDI, etc., or allophanate, biuretization, dimerization (uretidioneization), trimerization (isocyanurateization), adductation, Carbodiimidated derivatives; and blocked isocyanates obtained by blocking these with alcohols, phenols, ε-caprolactam, oximes, active methylene compounds, etc., and one or more selected from these may be used. Can be done.

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 formed film has excellent curability, exhibits more excellent foamability when the temperature rises, and can enhance the heat-resistant protection of the base material.

The polyol component (a1) and the polyisocyanate component (a2) are 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, the curability is excellent, a uniform film can be formed with a desired thickness, the foamability can be further enhanced, and the heat resistance protection performance of the base material can be enhanced.

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 accelerating the reaction of isocyanate groups to cure. Examples of the curing catalyst include amine-based catalysts, organometallic catalysts, and inorganic catalysts. For example, examples of amine-based catalysts include ethylenediamine, triethylenediamine, triethylamine, ethanolamine, diethanolamine, hexamethylenediamine, derivatives thereof, and mixtures with solvents thereof. 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, curing can be promoted, and the curability of the film-forming component (A) can be enhanced, so that the effect of the present invention can be enhanced.

Examples of the powder component (B) of the present invention include a foaming agent (b1), a carbonizing agent (b2), a flame retardant (b3), a filler (b4), and the like, and at least one of these is used. It includes.

Examples of the foaming agent (b1) 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 (b1) 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 (b1) 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 (b2) 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 (b2) 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 (b2) 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 (b3) include organophosphorus compounds such as tricresyl phosphate and diphenyl cresyl phosphate; chlorinated polyphenyl, chlorinated polyethylene, diphenyl chloride, triphenyl chloride, chlorinated paraffin, and fatty acid pentachloride. 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. Be done. These can be used alone or in combination of two or more. In the present invention, it is preferable to contain a phosphorus compound as the flame retardant (b3). The content of the flame retardant (b3) 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 (b4) 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 (b4) 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).

The coating material of the present invention contains at least one or more of the foaming agent (b1), the carbonizing agent (b2), the flame retardant (b3), and the filler (b4) as the powder component (B). It may be contained, but it is desirable that all of these components are contained. As a result, when the temperature rises due to a fire or the like, excellent foamability is exhibited, a good carbonized heat insulating layer is formed, heat resistance protection performance is exhibited, and heat resistance protection of the base material can be enhanced.

Further, in the present invention, the metal hydrate (b5) and the fiber (b6) can be included as the powder component (B). The metal hydrate (b5) exhibits endothermic properties due to a dehydration reaction or the like when the temperature rises, and is different from the filler (b4). Examples of such a metal hydrate (b5) 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 (b5) is preferably 0.1 to 20 μm (more preferably 0.2 to 15 μm, further preferably 0.3 to 8 μm, most preferably 0.4 to 3 μm). Is. The content of the metal hydrate (b5) is preferably 1 to 200 parts by weight (more preferably 5 to 100 parts by weight, still more preferably 8) 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 (b4) and the metal hydrate (b5) in combination. In this case, the filler (b4) and the metal hydrate (b5) 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 (b6) can enhance the thick coating property and suppress the cracking of the coating film. In addition, the fiber (b6) 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 (b6) 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 (b6) contains an inorganic fiber, and among them, artificial mineral fibers such as rock wool fiber, slag wool fiber, and glass fiber ceramic fiber are preferable. As a result, cracks in the coating can be further suppressed, and when the temperature rises due to a fire or the like, the coating can be less likely to sag, and the thermal conductivity inside the coating can be further enhanced. it can. As a result, it is possible to uniformly exhibit excellent foamability even inside the coating film (core portion), form a more uniform carbonized heat insulating layer, and further enhance the heat resistance protection performance of the base material.

The size of the fiber (b6) (fiber length and fiber diameter) may be set according to the specifications 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 (b6) 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 the high boiling point compound (C). The high boiling point compound (C) 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 containing such a high boiling point compound (C), the viscosity of the coating material and the heating residue can be optimized, and the dispersion stability of the powder component can be enhanced. Further, by mixing and reacting with the polyisocyanate component, a good film having excellent adhesion can be formed, in particular, the elasticity of the film can be improved and cracking of the film can be prevented. 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 (C) 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;

Trimetate 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 (C) 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 (C) 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, particularly preferably 18 to 50 parts by weight). When such a range is satisfied, it has excellent thick coating property, has excellent foaming property when the temperature rises due to a fire or the like, and can sufficiently exert the effect of maintaining the heat resistance protection performance of the base material. .. Further, in such a range, while sufficiently exhibiting the above heat resistance protection performance, sufficient adhesion (adhesiveness) even when the coating material of the present invention is repeatedly applied or when various top coating materials are applied. ) Can be ensured, so that a film having excellent finishability can be formed.

In addition, the additive may be any additive that does not significantly impair the effects of the present invention, for example, pigments, fibers, wetting agents, plasticizers, lubricants, preservatives, fungicides, algae-proofing agents, antibacterial agents, and diluents. Examples thereof include thickeners, leveling agents, dispersants, antifoaming agents, cross-linking agents, silane coupling agents, ultraviolet absorbers, antioxidants, halogen trapping agents, diluting solvents 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. ..

In the present invention, it is preferable to use a polyol composition containing the polyol component (a1) and the powder component (B) as a main agent and a polyisocyanate component (a2) as a curing agent as a two-component coating material. 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, that is, at the time of film formation). The powder component (B) can also be mixed with the polyisocyanate component (a2) (curing agent side).

(Film formation method)
The film-forming method of the present invention is to apply the above-mentioned coating material to a base material to form a film, and the above-mentioned coating material is foamed to be applied to the surface coating of structures such as buildings and civil engineering structures. It is suitable as a fireproof coating material. Specifically, the base material can be applied to various base materials such as walls, columns, floors, beams, roofs, stairs, ceilings, and doors. Applicable base materials include, for example, 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 method of applying the coating material to the base material is not particularly limited, and known coating tools such as sprays, rollers, brushes, and trowels can be used. In the present invention, when the coating material satisfies the above-mentioned viscosity and heating residue conditions, the film can be thickened even when various coating tools are used, and a uniform film can be formed. The coating material of the present invention can be diluted at the time of coating, but in this case, the viscosity of the coating material is 3 to 70 Pa · s (preferably 5 to 65 Pa · s, more preferably 7 to 60 Pa · s). ) Is preferably satisfied.

Further, when the coating material is applied, it may be applied by applying one step or several steps repeatedly so that the dry film thickness per step is preferably 400 μm or more (more preferably 500 to 5000 μm). Apply. As a result, a thick film can be formed with a small number of coating steps. 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.

A film can be formed by drying the film after applying the coating material. The drying temperature is preferably 0 ° C. or higher and 40 ° C. or lower (normal temperature), and can be heated if necessary. The drying time is preferably 4 hours or more, more preferably 24 hours or more.

In the present invention, in order to protect the coating film formed by the covering material, a topcoat material may be further applied if necessary. Such a topcoat material can be formed by applying a known covering material. As the topcoat material, for example, a coating material such as an acrylic resin type, a urethane resin type, an acrylic silicon resin type, a fluororesin type, an epoxy resin type, or a vinyl acetate resin type can be used. These can be used by one kind or two or more kinds, and two or more kinds of covering materials can be laminated and applied. The topcoat material may be applied by a known application method, and for example, a coating tool such as a spray, a roller, or a brush can be used.

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

(Coating materials 1 to 17)
Coating materials 1 to 17 were prepared according to the formulations shown in Table 1. The film-forming component (A) is a mixture of the polyol component (a1) and the polyisocyanate component (a2) so that the mixing ratio is NCO / OH equivalent ratio 1.2.
As a method for preparing the coating material, the component (a1), the component (b) to the component (g), the catalyst, and the additive are mixed by a conventional method to prepare a polyol composition (main agent), and then (a2). The components were mixed to prepare a coating material.

The following raw materials were used.
<Film forming component (A)>
・ Polyol component (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)
-Polyisocyanate component (a2)
(A2-1) Biuret-type hexamethylene diisocyanate (NCO content 23.5%)

<Powder component (B)>
・ Foaming agent (b1): Melamine ・ Carbide (b2): Pentaerythritol ・ Flame retardant (b3): Ammonium polyphosphate ・ Filler (b4): Titanium oxide ・ Metal hydrate (b5): Aluminum hydroxide (average) Particle size 1 μm)
-Fiber (b6): Rock wool fiber (average fiber length 125 μm, average fiber diameter 4.5 μm)

<High boiling point compound (C)>
High boiling point compound (c1): Diisononyl phthalate (boiling point 420 ° C.)
High boiling point compound (c2): diisononyl adipate (boiling point 227 ° C)
High boiling point compound (c3): di-2-ethylhexyl phthalate (boiling point 386 ° C)
High boiling point compound (c4): diisodecyl phthalate (boiling point 420 ° C.)
High boiling point compound (c5): Diundecyl phthalate (boiling point 523 ° C.)
High boiling point compound (c6): dibutyl phthalate (boiling point 340 ° C.)

<Others>
・ Curing catalyst: Organic metal catalyst ・ Additive 1: Dispersant, defoamer, etc. ・ Additive 2: Diluting solvent (aromatic hydrocarbon)

(Examples 1 to 13, Comparative Examples 1 to 4)
The following evaluations were carried out for each of the covering materials 1 to 17. The results are shown in Table 2.
<Evaluation of paintability>
Coating workability of the coating material when the coating material is applied to the entire surface of the base material (steel plate 1200 mm x 300 mm x thickness 9 mm) with a roller (medium hair roller) or a spray with an application amount of 3.0 kg / m ² . Was evaluated.
The evaluation criteria are "A" for those with good coating workability and the ability to form a uniform coating without sagging, and those with insufficient coating workability and the inability to form a uniform coating due to sagging. Was evaluated as "D" on a 4-point scale (excellent: A>B>C> D: inferior).

<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 2 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

Next, a coating material is spray-coated (dry film thickness 1.5 mm) on the entire surface of a steel sheet (length 150 mm × width 70 mm × thickness 1.6 mm) that has been previously coated with rust preventive coating, and cured at room temperature (25 ° C.) for 7 days. The sample [I] was used as a test piece, and the following evaluation was carried out.
<Adhesion evaluation>
The coating film of the test piece [I] is evaluated by peeling with a metallic spatula, and the one that cannot be easily peeled off is designated as "A" and the one that can be easily peeled off is designated as "D" (excellent: A> B). >C> D: Inferior).

<Heat resistance evaluation 1>
Based on the ISO 5660-1 cone calorimeter method, the foaming ratio when radiant heat of 50 kW / m ² is radiated to the surface of the test piece [I] for 15 minutes using an electric heater (CONEIII, manufactured by Toyo Seiki Co., Ltd.), and The temperature on the back surface of the steel sheet was measured. Each evaluation standard is as follows. The results are shown in Table 1.
(Effervescent)
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: 550 ° C or more (denseness)
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".

Examples 1 to 13 were excellent in coating property, thick film (thick coating property), and adhesiveness, and exhibited excellent heat resistance protection. On the other hand, in Comparative Example 1, the coatability and adhesion were inferior, and it was difficult to form a uniform film. Further, in Comparative Examples 2 and 3, the coatability was good, but it was difficult to thicken the film. In Comparative Example 4, sufficient heat-resistant protection was not obtained.

(Coating material 18 to 20)
The polyol compositions 18 to 20 shown in Table 2 and the above component (a2) are mixed so that the NCO / OH equivalent ratio of the polyol component and the polyisocyanate component is 1.2, respectively, to obtain coating materials 18 to 20. It was.

(Examples 14 to 17)
Further, the following evaluations were carried out for the covering material 2 and the covering materials 18 to 20.
<Thickening evaluation 2>
In the thickening evaluation 1, the evaluation was carried out in the same manner except that the coating material was applied with a wet film thickness of 3 mm. The results are shown in Table 2.
<Thickening evaluation 3>
In the thickening evaluation 2, 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 2.
<Adhesion evaluation>
A test body [I] was prepared by the same method as described above and evaluated. The results are shown in Table 2.

<Heat resistance evaluation 2>
Based on the ISO 5660-1 cone calorimeter method, the foaming magnification when radiant heat of 50 kW / m ² is radiated to the surface of the test piece [I] for 30 minutes using an electric heater (CONEIII, manufactured by Toyo Seiki Co., Ltd.), and The temperature on the back surface of the steel sheet was measured. Each evaluation standard is the same as the above heat resistance evaluation 1. The results are shown in Table 2.

Claims (2)

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 as the temperature rises.
The temperature rise of the coating film is 250 ° C. or higher.
The coating material contains a film-forming component (A) and a powder component (B), has a viscosity of 3 to 70 Pa · s, and has a heating residue of 70 to 98% by weight.
The film-forming component (A) contains a polyol component (a1) and a polyisocyanate component (a2).
It said polyol component (a1) has a molecular weight seen contains more than 1000 polyether polyol,
A film forming method comprising a foaming agent (b1) and a carbonizing agent (b2) as the powder component (B) . The coating material is applied by applying it in one or several steps.
The film forming method according to claim 1, wherein the dry film thickness per step is 400 μm or more.