JP2000309748A - Heat-resistant coating composition for steel, coating film, large-sized steel structure covered with the coating film, and method for coating steel structure - Google Patents

Abstract

(57) [Summary] (Modified) SOLUTION: The heat-resistant coating composition for steel material of the present invention comprises (A) a binder comprising alkyl silicate and / or a hydrolyzed initial condensate thereof, and (B) SiO _2. Silica powder (b1) having a content of 90% by weight or more and an iron compound content of 0.5% by weight or less, ZrSi
O ₄ content is 80% by weight or more, and iron compound content is
A 0.5% by weight or less, included in SiO ₂ content in the ZrSiO ₄ is 27 wt% or more, and shea Bu Rukon powder ZrO ₂ content is 53 wt% or more (b2), and the iron compound 1 wt% or more At least one extender pigment selected from the group consisting of no extender pigments (b3), (C) zinc powder, and (D) a white pigment comprising zinc oxide powder (d1) and / or titanium oxide powder (d2) And the iron compound content in the total composition comprising (A) to (D) is 0.5% by weight or less. The above composition is excellent in heat discoloration resistance and flame resistance, and can form a coating film capable of preventing thermal deterioration, discoloration and combustion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant coating composition for steel, a coating film thereof, a large steel structure covered with the coating film,
For more details on the method of painting steel structures,
Steel structures such as ships and steel plates before and after forming of large steel structures are coated with a zinc-based shop primer, then top-coated, and then welded after this top-coating.
When performing heating work with a gas burner, etc., a heat-resistant paint composition for a top coat that exhibits excellent heat-resistant discoloration, its coating film, a large steel structure covered with the coating film,
And a method for painting a steel structure.

[0002]

BACKGROUND ART Conventionally, large steel structures such as bridges and plants, and steel structures such as ships are coated with a zinc-based shop primer on the surface thereof, and the coated surface is further coated with an organic material according to the required performance. Paint (each resin, each color)
Has been overcoated. However, if welding work or heating with a gas burner is performed after this top coat, the top coat may be discolored by heat deterioration or may be damaged by combustion. The steel surface must be treated and repaired by repainting. As a result, not only does the number of work steps increase, but also it is necessary to secure personnel for performing these works, and to install and remove scaffolds and to perform repair work.

[0003] The inventors of the present invention have intensively studied to develop a top coating having excellent heat discoloration resistance, and to prevent deterioration, discoloration, and combustion of the coating due to welding, heating with a gas burner, or the like. , The paint is composed of inorganic materials,
It was confirmed that it was necessary to select a material that did not deteriorate, discolor, or burn due to heating. (1) To reduce organic components caused by the vehicle (vehicle) and to suppress thermal deterioration, (2) In the coating film It has been found that it is indispensable to suppress the iron content in the powder component of (1) and (3) to have anticorrosion properties, and have completed the present invention.

Japanese Patent Application Laid-Open No. 3-79675 describes that
Alkoxy silicate, alkyl trialkoxy silicate and / or their hydrolysis initial condensate (A)
And acidic water-dispersible colloidal silica (B), zinc dust (C), and powder (D) having a weight loss of 2% by weight or less selected from silica powder, rutile powder, synthetic rutile powder, chromium powder, and zircon powder (D). And a primary rust preventive paint for steel materials containing:

[0005]

An object of the present invention is to solve the problems associated with the prior art as described above, and to provide a heat-resistant coating composition for steel materials capable of forming a coating film having excellent heat discoloration resistance and flame resistance. An object of the present invention is to provide a coating film, a large-scale steel structure covered with the coating film, and a method for coating a steel structure.

[0006]

SUMMARY OF THE INVENTION The heat-resistant coating composition for steel according to the present invention comprises:
(A) Alkyl silicate and / or its hydrolysis
Binder consisting of precondensate, (B) SiO_TwoContent 9
0% by weight or more and the content of iron compound is 0.5 weight
% Or less silica powder (b1), ZrSiO_FourContent of
Is 80% by weight or more, and the content of the iron compound is 0.1%.
Not more than 5% by weight and ZrSiO_Four SiO inside
_TwoIs not less than 27% by weight and ZrO_TwoContent of
Is zircon powder (b2) containing at least 53% by weight, and iron
From the extender pigment (b3) containing no more than 1% by weight of the compound.
At least one extender selected from the group consisting of
Lead powder, and (D) zinc oxide powder (d1) and / or
Do not contain a white pigment consisting of titanium oxide powder (d2).
And iron in the total composition comprising (A) to (D)
The compound content is 0.5% by weight or less.
are doing.

The component (D) includes zinc oxide powder (d
Inorganic powder containing 1) is preferred, and zinc oxide powder (d
An inorganic powder containing 1) and titanium oxide powder (d2) is preferred. The coating film according to the present invention is formed from the above-described heat-resistant coating composition for steel. The large-sized steel structure according to the present invention is a ship or a large-sized steel structure covered with a coating film formed from the above-mentioned heat-resistant coating composition for steel materials.

The method for coating a steel structure according to the present invention is characterized in that the surface of a ship or a large steel structure or the surface of a zinc-based shop primer coating formed on the surface is coated with the above-mentioned heat-resistant paint composition for steel. It is characterized in that it is covered with a coating film formed from an object.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The heat-resistant coating composition for steel according to the present invention, its coating film, a large steel structure coated with the coating film, and a method of coating the steel structure will be specifically described below. . Heat-resistant coating composition for steel material The heat-resistant coating composition for steel material according to the present invention contains a binder (A), an extender pigment (B), zinc dust (C), and a white pigment (D).

[ Binder (A)] The binder (A) used in the present invention comprises an alkyl silicate and / or a hydrolyzed initial condensate thereof. The alkyl silicate has the formula (RO) ₃ Si [—O—Si (OR) ₂ —] _n OR (wherein R is usually an alkyl group having 1 to 6 carbon atoms, and n is usually 0 to 6). Certain), specifically, tetramethyl silicate, tetraethyl silicate, tetra-n-propyl silicate, tetra-i-propyl silicate, tetra-n-
Butyl silicate, tetra-sec-butyl silicate, methyl polysilicate, ethyl polysilicate and the like.

Specific examples of the alkyl silicate hydrolysis initial condensate include the above-mentioned alkyl silicate hydrolysis initial condensates. In the present invention,
The above alkyl silicates or hydrolyzed initial condensates thereof can be used alone or in combination of two or more. Examples of the combination of two or more types include ethyl silicate [trade name: ethyl silicate 40, Nippon Colcoat Co., Ltd.] composed of a mixture of an alkyl silicate and a hydrolysis initial condensate of the alkyl silicate. As the binder (A) used in the present invention, such ethyl silicate is preferable.

The hydrolysis initial condensate of an alkyl silicate is a known coloring agent used in inorganic zinc-rich paints and the like, and is obtained by hydrolyzing an alkyl silicate in the presence of an acidic catalyst according to a conventional method. In the present invention,
Since the binder (A) having an extremely low organic content as described above is used, it is possible to obtain a coating composition capable of forming a coating film having excellent heat resistance and flame resistance.

[Extended Pigment (B)] The extended pigment (B) used in the present invention has a SiO ₂ content of 90% by weight or more and an iron compound content of 0.5% by weight or less. The powder (b1) has a ZrSiO ₄ content of 80% by weight or more, an iron compound content of 0.5% by weight or less, and a SiO ₂ content of 27% in ZrSiO _4.
Zircon powder (b2) having a ZrO ₂ content of not less than 53% by weight and an iron compound in an amount of not less than 1% by weight.
This is the extender pigment (b3) that does not contain the above.

Examples of such silica stone powder (b1) include Snow Brand SP powder [trade name, manufactured by Marugama Kamado Ceramics Co., Ltd.],
Commercially available products such as snow-silica stone powder (trade name, manufactured by Marugama Kamado Porcelain Co., Ltd.). In addition, such zircon powder (b
Examples of 2) include commercially available products such as A-DAX (trade name, manufactured by Kinsei Matech Co., Ltd.). The zircon powder (b2) is a powder of a zirconium silicate mineral and has excellent heat resistance.

The extender (b3) containing no iron compound in an amount of 1% by weight or more has no thermal decomposition or thermal discoloration at 800 ° C. or less, is insoluble or hardly soluble in water, and has a white, colorless and pale color. At least one kind of inorganic powder can be arbitrarily selected and used from powders and fired products thereof.
Specifically, silica powder (trade name: Esilil 200, manufactured by Nippon Aerosil Co., Ltd.), silicates (zinc silicate, aluminum silicate, aluminum potassium silicate, aluminum sodium silicate, aluminum beryllium silicate, silicic acid) Calcium, magnesium silicate, magnesium calcium silicate, manganese silicate [trade name Nepheline A-270, manufactured by Oxelum Co., Ltd .; trade name Hibright # 325, manufactured by Kinsei Matek Co., Ltd .; trade name Hibright # 1250, Kinsei Matek Corporation
Manufactured), sulfate (barium sulfate), phosphate (calcium phosphate, barium phosphate, tricalcium phosphate [trade name, Taihei Chemical Industry Co., Ltd.]), borate (potassium aluminum borate, magnesium borate) , Aluminates (calcium aluminate), metal oxides (aluminum oxide, zirconium oxide, manganese oxide) and the like.

In the present invention, since the extender pigment (B) having an extremely small iron compound content is used as described above, a coating composition capable of forming a coating film having excellent heat discoloration resistance can be obtained. [Zinc powder (C)] The zinc powder (C) used in the present invention is:
Zinc powder commonly used as a pigment may be used. Zinc dust (C) exerts the action of an anticorrosive pigment.

[White Pigment (D)] The white pigment (D) used in the present invention is at least one inorganic powder selected from the group consisting of zinc oxide powder (d1) and titanium oxide powder (d2). . The zinc oxide powder (d1) is a white pigment and has excellent weather resistance and heat resistance. Zinc oxide powder (d1)
When mixed with zircon powder (b2), weather resistance and heat resistance are further improved. In addition, when the zinc oxide powder (d1) is mixed with the titanium oxide powder (d2), the strength of the coating film is improved, and there is an effect that choking is reduced and deterioration resistance due to outdoor exposure is improved. Further, the zinc oxide powder (d1)
When mixed with zircon powder (b2) and titanium oxide powder (d2), it has excellent weather resistance and heat resistance, and also has the effect of improving the strength of the coating film, reducing chalking, and improving the resistance to deterioration due to outdoor exposure. There is.

The titanium oxide powder (d2) is a white pigment. [Other components] The heat-resistant coating composition for steel according to the present invention may contain various solvents, inorganic chromatic pigments, organic bentonite, and polyethylene oxide, as necessary, in the same manner as ordinary inorganic zinc shop primers. An additive such as a silane compound can be blended within a range that does not impair the object of the present invention.

Specific examples of the solvent include alcohol solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol and butyl alcohol; hydrocarbon solvents such as toluene, xylene and hexane; acetone, methyl ethyl ketone (MEK) and methyl isobutyl. Ketone (M
Ketones such as IBK); ester solvents such as ethyl acetate, propyl acetate, butyl acetate, cellosolve acetate;
Ether solvents such as methyl cellosolve, cellosolve, and butyl cellosolve; and water. These solvents can be used alone or in combination of two or more.

[Blending Ratio] In the heat-resistant coating composition for steel materials according to the present invention, the binder (A), the extender pigment (B), and zinc are used in terms of performance such as hardness, strength, and adhesion of the coating film. End (C)
And the mixing ratio with the white pigment (D) is the weight ratio [(A) /
[(B) + (C) + (D)]], usually 1: 0.5 to 1:10, preferably 1: 1 to 1: 5, more preferably 1: 2 to 2
The ratio is 1: 4, and especially 1: 3 is preferable and practical.

In this case, the extender pigment (B) is composed of a total of 10 extender pigments (B), zinc dust (C) and white pigment (D).
The compounding amount is usually 20 to 90 parts by weight, preferably 30 to 80 parts by weight, and more preferably 50 to 70 parts by weight with respect to 0 parts by weight. Zinc powder (C) is a total of 10 particles of extender pigment (B), zinc powder (C) and white pigment (D).
0 to 1 part by weight, usually 1 to 15 parts by weight, preferably 2 parts by weight
10 to 10 parts by weight, more preferably 3 to 6 parts by weight.

The white pigment (D) is used in an amount of usually 5 to 70 parts by weight, preferably 10 to 60 parts by weight, based on 100 parts by weight of the total of the extender pigment (B), zinc dust (C) and white pigment (D). And more preferably 20 to 40 parts by weight. When the corrosion resistance is enhanced by using more zinc powder (C), the mixing ratio of the binder (A) with the extender pigment (B), zinc powder (C) and white pigment (D) is as follows. The weight ratio [(A) / [(B) + (C) + (D)]] is preferably 1: 1 to 1: 5, particularly preferably 1: 3.5, and is practical.

In this case, the zinc dust (C) is a total of 10 parts of the extender pigment (B), the zinc dust (C) and the white pigment (D).
0-wt. Parts, preferably 5-85 wt. Parts, more preferably 25-75 wt. Parts, most preferably 40-6 wt. Parts.
It is blended at a ratio of 0 parts by weight. The extender pigment (B) is preferably 5-90 parts by weight, more preferably 10-80 parts by weight, based on 100 parts by weight of the total of the extender pigment (B), zinc dust (C) and white pigment (D). Most preferably 20
It is blended at a ratio of ４０40 parts by weight. The white pigment (D)
It is preferably 10 to 90 parts by weight, more preferably 15 to 65 parts by weight, and most preferably 20 to 40 parts by weight based on 100 parts by weight of the total of the extender pigment (B), the zinc dust (C) and the white pigment (D). Parts are blended.

The white pigment (D) is, as described above, at least one inorganic powder selected from the group consisting of zinc oxide powder (d1) and titanium oxide powder (d2). The mixing ratio of the components is appropriately determined according to the desired physical properties. [Preparation / Storage / Coating] The heat-resistant coating composition for steel according to the present invention can be prepared according to a conventional method.

The binder (A), which is a vehicle, can be made into a liquid state by using an ordinary paint production (dispersion) apparatus together with various solvents and additives. The extender pigment (B), zinc powder (C), and white pigment (D) can be made into a liquid state by using an ordinary paint production (dispersion) device together with various solvents and additives.

The binder (A) as a vehicle may be mixed with a mixture (powder and liquid) of the extender pigment (B), zinc dust (C) and white pigment (D) immediately before use.
In the present invention, the liquid component containing the binder (A) and the paste pigment containing the extender pigment (B), the zinc powder (C) and the white pigment (D), mortar, liquid and any other properties can be used. . The liquid component containing the binder (A) and the paste containing the extender pigment (B), zinc dust (C) and white pigment (D) are stored, transported and handled in separate containers, respectively, and are usually coated. It is sometimes kneaded by a conventionally known method.

Then, it is applied to the surface of a steel structure such as a ship or a large steel structure, or to the surface of a zinc-based shop primer coating film formed on the surface by ordinary means such as air spraying or airless spraying. Then, it may be dried by natural drying or hot air drying. As such a zinc-based shop primer, a conventionally known zinc-based shop primer can be used, and among them, an inorganic zinc paint is preferably used.

[0028]

The heat-resistant coating composition for steel according to the present invention has excellent heat discoloration resistance and flame resistance, and can form a coating film capable of preventing thermal deterioration, discoloration and combustion.
Since the coating film according to the present invention is formed from this coating composition, it has excellent heat discoloration resistance and flame resistance.

According to the method for coating a steel structure according to the present invention, there is provided a steel structure such as a ship or a large steel structure covered with the coating film. According to the present invention, for example, in a shipbuilding process, a repair process relating to discoloration, deterioration, damage due to burning, and the like of a coating film caused by welding, heating work by a gas burner, or the like becomes unnecessary. This eliminates the need for personnel, man-hours, erection / removal of scaffolds, and paint.

The heat-resistant coating composition for steel according to the present invention comprises:
It can be used as a topcoat paint to be applied on the primary rust-preventive paint film, and is suitable for painting steel structures such as ships and large steel structures. It is suitable for painting the ceiling heat insulation section of the room and the ceiling and wall of the superstructure. Further, the heat-resistant coating composition for steel materials according to the present invention, in which the amount of zinc powder (C) is increased to increase the corrosion resistance, can be used as a primary rust-preventive coating.

[0031]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The heat resistance test in the examples was performed according to the following method. [Heat resistance test] Length 200 mm, width 100 mm, thickness 3.2
mm on a steel plate (manufactured by Nippon Test Panel Co., Ltd., sandblasted plate) so as to have a dry film thickness of 40 to 50 μm, dried in a 25 ° C. atmosphere for 7 days, and then heated from behind with an acetylene gas burner Then, after baking until the surface temperature of the steel sheet on the front side reached 600 ° C. and 800 ° C., it was allowed to stand and was naturally cooled to room temperature.

On the coating film of the coated plate obtained as described above, 6 lines vertically and horizontally were cut at intervals of 4 mm with a cutter knife to produce 25 grids, and then an adhesive cellophane was placed thereon. After adhering the tape, the cellophane tape was peeled off at a stretch, and the adhesion of the coating film was evaluated based on the degree of peeling of the coating film in the cells. Further, the color difference [ΔL, Δa, Δb, ΔE between the coating film before baking and the coating film after baking is described.
(JISK5400)] using a color difference meter, and the color difference was used as an index of heat discoloration resistance.

[0033]

Example 1 Main agent (vehicle) having the following composition
And a white paste were prepared as follows. (1) Main agent As the main agent, 50.0 parts by weight of ethyl silicate 40 [trade name, manufactured by Nippon Colcoat Co., Ltd.] as a binder (A), 0.2 parts by weight of 3.5% hydrochloric acid, and 5.5 parts by weight of water Parts, 19.3 parts by weight of isopropyl alcohol and 25.0 parts by weight of ethyl alcohol were heated to 50 ° C., and stirred for 3 hours to prepare. (2) White Paste As for the white paste, 20 parts by weight of Snow Brand SP powder [trade name, manufactured by Marugama Kamado Ceramics Co., Ltd.], 3 parts by weight of zinc powder, 15 parts by weight of zinc oxide powder, zircon A as powder
-Paint 20 parts by weight of DAX [trade name; manufactured by Kinsei Mate Co., Ltd.], 2 parts by weight of titanium oxide powder, 2 parts by weight of silica powder [trade name: Esilil 200, Nippon Aerosil Co., Ltd.] and 38 parts by weight of isopropyl alcohol. It was prepared by mixing uniformly using a shaker.

[0034] A coating composition was prepared by mixing 100 parts by weight of the main agent obtained as described above and 250 parts by weight of a white paste, and then applied to the surface of a steel sheet by air spray and air-dried for 7 days. After that, the heat resistance test was performed.
Table 1 shows the results.

[0035]

[Table 1]

[0036]

Example 2 The same composition as the main agent (vehicle) used in Example 1 was prepared as the main agent, and a light gray paste was prepared as follows. For the light gray paste, 10 parts by weight of snow-brand SP powder [trade name, manufactured by Marugama Kamado Porcelain Co., Ltd.], 40 parts by weight of zinc powder,
10 parts by weight of zinc oxide powder, A-DAX as zircon powder
[Trade name: Kinsei Matech Co., Ltd.] 10 parts by weight, titanium oxide powder 1 part by weight, silica powder
00, Nippon Aerosil Co., Ltd.] and 2 parts by weight of isopropyl alcohol using a paint shaker.

A coating composition was prepared by mixing 100 parts by weight of the base material obtained as described above and 250 parts by weight of a light gray paste, and then applied to the surface of a steel sheet by air spray, and allowed to dry for 7 days. After drying, the coating composition prepared in Example 1 was further overcoated with an air spray, allowed to dry naturally for 7 days, and then subjected to the heat resistance test. Table 2 shows the results.

[0038]

[Table 2]

[0039]

Examples 3 to 6 A coating composition was prepared by mixing 100 parts by weight of the main ingredient having the composition shown in Table 3 below with 250 parts by weight of the white paste prepared in Example 1.
The composition was applied to the surface of a steel sheet by air spray and naturally dried for 7 days, and then subjected to the above heat resistance test. Table 4 shows the results.

The amount of the ethyl silicate 40 in the main agent (vehicle) is determined based on the “sag, drying time” when the coating composition is prepared and applied by air spray, and the main agent (vehicle). It is appropriately determined according to desired physical properties such as “storage stability”.

[0041]

[Table 3]

[0042]

[Table 4]

[0043]

Examples 7 to 9 The same composition as the main agent (coloring agent) used in Example 1 was prepared as the main agent, and a white paste was prepared in the mixing ratio shown in Table 5. After mixing 100 parts by weight of the main agent and 250 parts by weight of each white paste to prepare a coating composition, the composition was applied to the surface of a steel plate by air spray, allowed to dry naturally for 7 days, and then subjected to the above heat resistance test. .
Table 6 shows the results.

[0044]

[Table 5]

[0045]

[Table 6]

[0046]

Comparative Examples 1 to 5 The same composition as the main agent (coloring agent) used in Example 1 was prepared as the main agent, and a white paste was prepared in the mixing ratio shown in Table 7. After mixing 100 parts by weight of the main agent and 250 parts by weight of each white paste to prepare a coating composition, the composition was applied to the surface of a steel plate by air spray, allowed to dry naturally for 7 days, and then subjected to the above heat resistance test. .
Table 8 shows the results.

[0047]

[Table 7]

[0048]

[Table 8]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 5/18 C09D 5/18 7/12 7/12 Z F-term (Reference) 4D075 CA18 DB02 DC05 DC08 DC08 EB42 EC10 EC13 EC54 4J038 DL021 HA066 HA216 HA446 HA456 JC30 KA08 KA20 NA14 PA07 PC02

Claims (4)

[Claims] (1) An alkyl silicate and / or (A)
A binder comprising the hydrolysis initial condensate, (B) SiO
_TwoContent of 90% by weight or more and content of iron compound
Silica powder (b1) having an amount of 0.5% by weight or less, ZrSi
O_FourIs 80% by weight or more, and the iron compound
The content is 0.5% by weight or less, and ZrSiO_Four inside
SiO_TwoIs not less than 27% by weight and Zr
O_TwoZircon powder (b) having a content of
2) and extender containing no more than 1% by weight of iron compound
At least one constitution selected from the group consisting of (b3)
Pigment, (C) zinc dust, and (D) zinc oxide powder (d1)
And / or white pigment comprising titanium oxide powder (d2)
And comprising the above (A) to (D)
The content of the iron compound in the composition is 0.5% by weight or less.
A heat-resistant coating composition for steel materials, characterized in that: (2) An alkyl silicate and / or (A)
A binder comprising the hydrolysis initial condensate, (B) SiO
_TwoContent of 90% by weight or more and content of iron compound
Silica powder (b1) having an amount of 0.5% by weight or less, ZrSi
O_FourIs 80% by weight or more, and the iron compound
The content is 0.5% by weight or less, and ZrSiO_Four inside
SiO_TwoIs not less than 27% by weight and Zr
O_TwoZircon powder (b) having a content of
2) and extender containing no more than 1% by weight of iron compound
At least one constitution selected from the group consisting of (b3)
Pigment, (C) zinc dust, and (D) zinc oxide powder (d1)
And / or white pigment comprising titanium oxide powder (d2)
And comprising the above (A) to (D)
The content of the iron compound in the composition is 0.5% by weight or less.
Characterized by being formed from a heat-resistant coating composition for steel materials
Paint film. (A) an alkyl silicate and / or
A binder comprising the hydrolysis initial condensate, (B) SiO
_TwoContent of 90% by weight or more and content of iron compound
Silica powder (b1) having an amount of 0.5% by weight or less, ZrSi
O_FourIs 80% by weight or more, and the iron compound
The content is 0.5% by weight or less, and ZrSiO_Four inside
SiO_TwoIs not less than 27% by weight and Zr
O_TwoZircon powder (b) having a content of
2) and extender containing no more than 1% by weight of iron compound
At least one constitution selected from the group consisting of (b3)
Pigment, (C) zinc dust, and (D) zinc oxide powder (d1)
And / or white pigment comprising titanium oxide powder (d2)
And comprising the above (A) to (D)
The content of the iron compound in the composition is 0.5% by weight or less.
Coated with a coating formed from a heat-resistant coating composition for steel
A large steel structure characterized by being made. 4. The surface of a ship or a large steel structure,
Is a zinc-based shop primer formed on these surfaces.
-Clean the surface of the coating with (A) alkyl silicate and / or
Or a binder comprising the hydrolysis initial condensate, (B) S
iO_TwoThe content is 90% by weight or more and the iron compound
Silica powder (b1) having a content of 0.5% by weight or less, Zr
SiO_FourIs 80% by weight or more, and
Is 0.5% by weight or less and ZrSiO_Four
SiO inside_TwoIs 27% by weight or more, and
ZrO_TwoZircon powder having a content of at least 53% by weight
(B2) and a constitution not containing 1% by weight or more of an iron compound
At least one kind selected from the group consisting of pigments (b3)
Extender pigment, (C) zinc powder, and (D) zinc oxide powder (d
1) White color composed of titanium oxide powder (d2) and / or
Containing a pigment, and from the above (A) to (D)
The content of iron compound in the total composition is 0.5% by weight or less.
Coated with a coating formed from a heat-resistant coating composition for a steel material
A method for painting a steel structure.