JP2019183428A - Coating structure - Google Patents

Abstract

To provide a coating structure having excellent foaming properties and capable of maintaining a heat-resistant protective performance of a base material.SOLUTION: A coating structure having a coating film 2 on the outer peripheral surface of a base material 1 is a concrete filled steel pipe in which a concrete 12 is filled inside the steel pipe 11; the coating film is formed by a coating material which forms a carbonized insulating layer by a temperature rise, and the coating material contains a thermosetting resin as a resin component.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a novel covering structure.

In recent years, building structures have become taller and larger, and the excellent rigidity and strength of concrete-filled steel pipes (CFT pillars) filled with concrete have attracted attention. Buildings are becoming popular. This CFT structure has a feature that the temperature of the steel material is not easily raised because the heat capacity of the filled concrete is large even though the steel material is located on the surface. For this reason, it has been attracting attention as a fireproof coating structure, and it is possible to actually eliminate or reduce the need for a fireproof coating material. However, depending on the building, higher heat protection performance may be required.

On the other hand, for example, a structure in which a CFT column is coated with an inorganic board such as a calcium silicate molding plate or a gypsum molding plate, or rock wool is known (for example, Patent Documents 1 and 2).

JP 2003-105890 A JP 2013-028924 A

  However, in the structures such as Patent Documents 1 and 2, the coating thickness may increase. On the other hand, it is possible to adopt a conventional heat-foamable coating material or the like, but because the CFT pillar has a large heat capacity, the steel material temperature is difficult to rise, and good foamability may not be obtained. There was still room for improvement in order to obtain the heat-resistant protection performance.

  In order to solve such a problem, the present inventors showed excellent foamability by coating a coating material containing a specific resin component in a coating structure based on a concrete-filled steel pipe, and excellent It has been found that the heat-resistant protection performance can be maintained, and the present invention has been completed.

That is, the present invention has the following characteristics.
1. A coating structure having a coating on the outer peripheral surface of the substrate,
The base material is a concrete-filled steel pipe in which concrete is filled inside the steel pipe,
The coating is formed by a coating material that forms a carbonized thermal insulation layer by increasing the temperature,
The said covering material contains a thermosetting resin as a resin component (a), The covering structure characterized by the above-mentioned.
2. The coating material includes a polyol component (a1) and a polyisocyanate component (a2) as a resin component (a). The covering structure according to 1.

The present invention relates to a covering structure having a coating on the outer peripheral surface of a base material, wherein the base material is a concrete-filled steel pipe filled with concrete in a steel pipe, and the coating is carbonized and insulated by temperature rise. It is formed by a covering material that forms a layer. When the coating material contains a thermosetting resin as the resin component (a), it exhibits excellent foamability when the temperature rises due to a fire or the like, and can improve the heat resistance of the substrate.

It is sectional drawing which shows an example of this invention covering structure.

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

  An example of the covering structure of the present invention is shown in FIG. In FIG. 1, the base material 1 has a coating 2 on the outer peripheral surface. The base material 1 is a concrete-filled steel pipe in which concrete 12 is filled in a steel pipe 11. If the inside is hollow, the cross-sectional shape of the steel pipe 11 is not particularly limited. For example, a square steel pipe, a round (circular) steel pipe, a square double steel pipe, a round (circular) double steel pipe, or the like is used. can do. The double steel pipe has an outer steel pipe and an inner steel pipe, and concrete 12 is filled between the outer steel pipe and the inner steel pipe (concrete-filled double steel pipe). The thickness, size, length, etc. of the steel pipe 11 are not particularly limited as long as they are known. Moreover, the steel pipe 11 of the base material 1 may be subjected to some surface treatment (rust prevention treatment, flame retardant treatment, etc.) on the surface thereof.

  The coating 2 formed on the outer peripheral surface of the base material 1 (concrete-filled steel pipe) is formed by a coating material that forms a carbonized heat insulation layer when the coating is heated. Hereinafter, the covering material will be described.

  The coating | covering material 2 of this invention is characterized by including a thermosetting resin as a resin component (a). In the present invention, by including a thermosetting resin as the resin component (a), excellent heat resistance protection can be exhibited even for a base material having a large heat capacity such as a concrete-filled steel pipe. Although this action mechanism is not limited to the following, for example, when a base material having a large heat capacity such as a concrete-filled steel pipe is exposed to a high temperature due to a fire or the like, the temperature of the base material surface slowly rises. . When the resin component of the coating formed on the surface of such a base material contains a thermosetting resin, it is less likely to be in a molten state compared to the case of using only a thermoplastic resin, and it suppresses dripping of the coating and efficiently foams. Thus, the carbonized heat insulating layer can be stably formed. It is considered that this makes it possible to exhibit excellent heat protection properties.

The thermosetting resin in the present invention may be one having a reactive functional group, and one composed of one component or two or more components can be used. Specifically, those composed of one or more resins, those composed of one or more resins and one or more curing agents can be used. Examples of such resins include epoxy resins, urethane resins, silicone resins, acrylic silicone resins, alkyd resins, melamine resins, polycarbonate resins, phenol resins, acrylic resins, polyester resins, polyether resins, vinyl resins, vinyl acetate resins. , Polyamide resin, fluororesin, amino resin and the like, and are not particularly limited, such as water dispersion type, water-soluble type, weak solvent type, strong solvent type, NAD type, powder type and the like. In the present invention, in particular, one or more selected from epoxy resins, urethane resins, silicon resins, acrylic silicon resins, vinyl acetate resins, and fluororesins are preferably used.

Examples of the reactive functional group include a carboxyl group, a carbodiimide group, an epoxy group, an aziridine group, an oxazoline group, a hydroxyl group, an isocyanate group, a carbonyl group, a hydrazide group, an epoxy group, an amino group, and an alkoxysilyl group.
Examples of such a combination of reactive functional groups include carboxyl group and carbodiimide group, carboxyl group and epoxy group, carboxyl group and aziridine group, carboxyl group and oxazoline group, hydroxyl group and isocyanate group, carbonyl group and hydrazide group, epoxy Combinations of groups, amino groups, alkoxysilyl groups, and the like can be given.

  The thermosetting resin in the present invention has one or more kinds of combinations of such reactive functional groups. In particular, a preferable combination of reactive functional groups includes at least one selected from a carboxyl group and an epoxy group, a hydroxyl group and an isocyanate group, an epoxy group and an amino group, and an alkoxysilyl group.

Among them, as the thermosetting resin of the present invention, a combination of a hydroxyl group and an isocyanate group, for example, a polyol compound (a1) (hereinafter also referred to as “(a1) component”) and a polyisocyanate compound (a2) (hereinafter referred to as “( The combination of “a2) component”) is preferred. These form a film by mixing and reacting the components (a1) and (a2). Examples of such component (a1) include polyether polyol, polyester polyol, castor oil, castor oil-modified polyol, epoxy-modified polyol, silicone-modified polyol, acrylic polyol, polycarbonate polyol, polylactone polyol, polybutadiene polyol, polypentadiene polyol, and the like. Of these, one or more of them can be used.

In particular, in the present invention, a polyether polyol is included as the component (a1), and the molecular weight thereof is 1000 or more (preferably 3000 or more and 20000 or less, more preferably 5000 or more and 18000 or less, further preferably 6000 or more and 15000 or less, and most preferably 6500. It is preferable that it is 12000 or less. By using such a polyol component, it has excellent foamability due to the temperature rise of the film 2 (preferably the film surface temperature is 200 ° C. or higher, more preferably 250 ° C. or higher), and the substrate 1 is heat-resistant. Performance can be increased. In the present invention, the molecular weight of the polyol compound (a1) is a number average molecular weight (Mn), and is a so-called polystyrene equivalent molecular weight obtained by gel permeation chromatography using a polystyrene polymer as a reference.

  The polyether polyol can be obtained, for example, by addition polymerization of polyhydric alcohols such as trimethylolpropane, glycerin, hexanetriol, pentaerythritol derivatives, sorbitol, and neopentyl glycol, and alkylene oxides such as ethylene oxide and propylene oxide. Is. 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 terminal is more preferable. is there. Further, the polyether polyol preferably includes a polyether polyol having three or more functional groups having active hydrogen atoms (functional group number of 3 or more). In this case, since it is excellent in curability and can form a film stably, the effect of this invention is easy to be acquired. A hydroxyl group is suitable as the functional group having an active hydrogen atom.

Such a polyether polyol preferably has a hydroxyl value of 3 to 150 mgKOH / g (more preferably 5 to 100 mgKOH / g, still more preferably 7 to 40 mgKOH / g, most preferably 10 to 30 mgKOH / g). . By using such a polyol component, more excellent foamability can be exhibited, and the heat resistance protection performance of the substrate can be enhanced.

Moreover, it is preferable that content of the said polyether polyol is 90 weight% or more (more preferably 95 weight% or more) with respect to the whole quantity of a polyol component (a1). In addition, an embodiment in which the (a1) polyol component is only a polyether polyol is also suitable.

  Examples of the polyisocyanate compound (a2) of the present invention include toluene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (pure-MDI), polymeric MDI, xylylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), and isophorone. Diisocyanate (IPDI), hydrogenated XDI, hydrogenated MDI, etc., or allophanated, biuretized, dimerized (uretidioneated), trimerized (isocyanurated), adducted, carbodiimidated derivatives; and these Examples include blocked isocyanates blocked with alcohols, phenols, ε-caprolactam, oximes, active methylene compounds, etc., and one or more selected from these can be used. That.

In the present invention, it is preferable to include hexamethylene diisocyanate (HMDI) and / or a derivative thereof (hereinafter also referred to as “HMDIs”) as the component (a2). 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). Moreover, the aspect in which a polyisocyanate component (a2) consists only of HMDIs is also suitable. Moreover, as a derivative | guide_body, a biuret body and / or an isocyanurate body are suitable. In such a case, the formed coating is excellent in curability, exhibits better foamability when the temperature rises, and can improve the heat-resistant protection of the substrate.

The mixing of the polyol compound (a1) and the polyisocyanate compound (a2) is preferably 0.6 to 3.5 (more preferably 1 to 2.5) in the NCO / OH equivalent ratio of the component (a1) and the component (a2). More preferably, the ratio is 1.1 to 1.9). In such a case, it is excellent in sclerosis | hardenability, a uniform film can be formed with desired thickness, foamability can be improved further, and the heat-resistant protection performance of a base material can be improved.

  In this invention, the curing catalyst which accelerates | stimulates reaction of (a1) component and (a2) component can be used together. A curing catalyst is a substance having an action of promoting the curing by reaction of isocyanate groups. Examples of the curing catalyst include various amine-based catalysts, organometallic catalysts, inorganic catalysts, and the like. Examples of the amine catalyst include ethylenediamine, triethylenediamine, triethylamine, ethanolamine, diethanolamine, and 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; and organometallic salts such as potassium acetate, zinc stearate, lead stearate, aluminum stearate and tin octylate. Examples of the inorganic catalyst include tin chloride. These can be used by 1 type (s) or 2 or more types, and can also be mixed and used for a solvent. In the present invention, it is particularly preferable to include an organometallic catalyst. In this case, the curing can be promoted and the curability of the resin component (a) can be enhanced, so that the effect of the present invention can be enhanced.

  Furthermore, the coating material for forming the coating film 2 of the present invention may include, for example, a foaming agent (b), a carbonizing agent (c), a flame retardant (d), a filler (e), and the like.

Examples of the foaming agent (b) include melamine and derivatives thereof, dicyandiamide and derivatives thereof, azobistetrasome and derivatives thereof, azodicarbonamide, urea and thiourea. 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 resin component (a). In addition, the foaming agent (b) of the present invention imparts a foaming action to the coating by a temperature rise during a fire or the like, and specifically, when the temperature of the coating surface is preferably 200 ° C. or higher. It gives a foaming action.

Examples of the carbonizing agent (c) include pentaerythritol, dipentaerythritol, trimethylolpropane, starch, and casein. These can be used alone or in combination of two or more. In the present invention, pentaerythritol and dipentaerythritol are particularly preferable in that they are excellent in dehydration cooling effect and carbonized heat insulation layer forming action. 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 resin component (a). In addition, the carbonizing agent (c) of this invention provides the effect | action which forms a carbonization heat insulation layer by carrying out dehydration carbonization with the carbonization of the said resin component (a) by the temperature rise at the time of a fire etc.

Examples of the flame retardant (d) include organic phosphorus 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 and tetrachlorophthalic anhydride; antimony compounds such as antimony trioxide and antimony 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 aluminum phosphate; other inorganic compounds such as zinc borate and sodium borate It is done. These can be used alone or in combination of two or more. In this invention, it is preferable that a phosphorus compound is included as a flame retardant (d). 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 resin component (a).

Examples of the filler (e) include talc, calcium carbonate, sodium carbonate, aluminum oxide (alumina), titanium oxide, zinc oxide, silica, clay, clay, shirasu, mica, quartz sand, quartzite powder, quartz powder, and barium sulfate. Etc. 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 resin component (a).

Furthermore, in this invention, in addition to the said component, metal hydrate (f) can also be included. The metal hydrate (f) exhibits endothermic properties due to a dehydration reaction or the like when the temperature rises, and is different from the filler (e). Examples of such 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, still more preferably 0.3 to 8 μm, most preferably 0.4 to 3 μm). It 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 to 25 parts by weight based on 100 parts by weight of the solid content of the resin 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, since the foaming property, in particular, the shrinkage of the carbonized heat insulation layer under high temperature can be suppressed and a stable carbonized heat insulation layer can be formed, the effect of the present invention can be enhanced. The average particle diameter is measured by a laser diffraction particle size distribution measuring device.

  Other additives may be used as long as they do not significantly inhibit the effects of the present invention. For example, pigments, fibers, wetting agents, plasticizers, lubricants, preservatives, antifungal agents, antialgae agents, antibacterial agents, Examples thereof include a viscosity agent, a leveling agent, a dispersant, an antifoaming agent, a crosslinking agent, a silane coupling agent, an ultraviolet absorber, an antioxidant, a halogen scavenger, and a diluent solvent.

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

  The present invention is preferably a two-pack type 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) (further, the metal hydrate (f) and the curing catalyst) are respectively Although it may be mixed with at least one of the main agent and the curing agent, it is preferably mixed with the main agent in the present invention. Moreover, each component can also be added at the time of mixing of a main ingredient and a hardening | curing agent.

(Coating structure)
The coating structure of the present invention is a structure in which the coating 2 is formed by applying the coating material to the outer peripheral surface of the base material 1 (the outer peripheral surface of the steel pipe 11).

  When the coating material of the present invention is applied to the substrate 1, for example, it may be applied in one or several steps using an application tool such as a spray, a roller, a brush, or a trowel. However, it is applied so that the dry film thickness per step is preferably 400 μm or more (more preferably 500 to 5000 μm). Thereby, a thick film can be formed with few coating processes. The film thickness finally formed may be appropriately set depending on desired functionality, application site, and the like, but is preferably about 0.4 to 30 mm (more preferably 1 to 10 mm).

  The coating film 2 can be formed by drying the coating 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 as necessary. The drying time is preferably 4 hours or longer, more preferably 24 hours or longer.

  In this invention, in order to protect the film 2 formed with the said coating | covering material, a top coat material can also be further applied as needed. Such a top coating material can be formed by applying a known coating material. As the top coating material, for example, an acrylic resin-based, urethane resin-based, acrylic silicon resin-based, or fluororesin-based coating material can be used. The top coating material may be applied by a known coating method, and for example, a coating instrument such as a spray, a roller, or a brush can be used.

  Hereinafter, an Example is shown and the characteristic of this invention is clarified more.

<Manufacture of coating material>
For 100 parts by weight of resin component (a), 85 parts by weight of foaming agent (b), 60 parts by weight of carbonizing agent (c), 350 parts by weight of flame retardant (d), 80 parts by weight of filler (e), 1 part by weight of catalyst Parts and 10 parts by weight of additive 1 and 70 parts by weight of additive 2 were mixed and stirred to prepare a coating material. The resin component (a) is a thermosetting resin mixed so that the mixing ratio of the polyol component (a1) and the polyisocyanate component (a2) is an NCO / OH equivalent ratio of 1.2.
In addition, as a preparation method of a coating | covering material, (a1) component, (b) component-(e) component, a catalyst, and an additive are mixed by a conventional method to prepare a polyol composition (main agent), and then (a2) The ingredients were mixed to prepare a coating material.

In addition, the following were used as a raw material.
-Resin component (a)
(A1): Polyether polyol (polymer of ethylene oxide and propylene oxide using glycerol as an initiator, number average molecular weight 7000, number of functional groups 3, hydroxyl value 24 mgKOH / g, terminal ethylene oxide addition)
(A2) Biuret type hexamethylene diisocyanate / foaming agent (b): melamine / carbonizing agent (c): dipentaerythritol / flame retardant (d): ammonium polyphosphate / filler (e): titanium oxide / curing catalyst: organic Metal catalyst / additive 1: Dispersant, defoaming agent, etc./Additive 2: Diluent solvent (aromatic hydrocarbon)

As shown in FIG. 1, the above-mentioned coating material is applied by spray (dry film thickness 5 mm) to the outer peripheral surface of a concrete-filled steel pipe filled with concrete inside a steel pipe (square cross-sectional shape), and at room temperature (25 ° C. ) And cured for 7 days to obtain test specimens. When this test body was subjected to a heating test, it exhibited excellent foaming properties and formed a dense carbonized heat insulating layer, resulting in excellent heat protection.

1. Base material 11. Steel pipe 12. Concrete 2. Coating

Claims (2)

A coating structure having a coating on the outer peripheral surface of the substrate,
The base material is a concrete-filled steel pipe in which concrete is filled inside the steel pipe,
The coating is formed by a coating material that forms a carbonized thermal insulation layer by increasing the temperature,
The said covering material contains a thermosetting resin as a resin component (a), The covering structure characterized by the above-mentioned. The said coating | covering material contains a polyol component (a1) and a polyisocyanate component (a2) as a resin component (a), The covering structure of Claim 1 characterized by the above-mentioned.

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