JP2019006982A - Heat-resistant paint composition, heat-resistant coating film, substrate with heat-resistant coating film and production method thereof - Google Patents

Abstract

A heat-resistant coating composition capable of forming a coating film exhibiting excellent corrosion protection in a severe corrosive environment such as "under a heat insulating material" without heating and drying when forming a coating film. . The present invention relates to a heat-resistant paint composition, a heat-resistant paint film, a substrate with a heat-resistant paint film, and a method for producing the same, wherein the heat-resistant paint composition comprises a siloxane-based binder (A), a mica (B), and a mica-like material. Contains iron oxide (C). [Selection diagram] None

Description

  The present invention relates to a heat-resistant coating composition, a heat-resistant coating film, a substrate with a heat-resistant coating film, and a method for producing the same.

  In piping such as plant structures, a heat insulating material is often installed around the piping (steel pipe) in order to prevent heat dissipation to the outside air and heat absorption from the outside air and suppress energy loss. However, rainwater that has entered the gap between the heat insulating material and the steel (eg, carbon steel, low alloy steel) tube or water that has aggregated at the location forms a water film on the surface of the steel tube, causing corrosion under the heat insulating material (CUI). : Corrosion Under Insulation). The CUI means that local corrosion erosion occurs by forming a corrosion battery on the steel pipe surface due to the water film. Since the corrosion rate is faster than the general corrosion that occurs in the outdoor air, it is a big problem in the maintenance management of plant structures.

  Furthermore, the CUI has a corrosion and erosion site under the heat insulating material (enclosed by the heat insulating material), so that the water that has entered once tends to stay and the wet state is maintained over a long period of time, depending on the operating conditions of the plant. Because the pipes may be exposed to high temperatures, the progress of corrosion, which is an oxidation reaction, is promoted, and plant structures are often installed in beach areas rich in sea salt particles that can be corrosive factors Therefore, the corrosion erosion is likely to become serious due to the fact that the sea salt particles promote the progress of corrosion.

Therefore, for the purpose of preventing the corrosion and the like, a pipe used for a plant structure or the like is provided with an anticorrosion coating (heat-resistant coating) on the outer surface thereof.
Pipings used for plant structures and the like are exposed to various temperature environments depending on the operating conditions of the plant, so the heat-resistant temperature and heat-resistant cooling cycle required for the anticorrosive coating (heat-resistant coating) used in the piping Conditions also vary widely, and for example, resistance to ultra-high temperatures of 600 ° C. or higher may be required. For this reason, conventionally, it has been necessary to scrutinize the operating conditions (temperature conditions) of the plant, and to select and apply an anticorrosive coating film (heat resistant coating film) suitable for the conditions.

Usually, a heat-resistant coating film obtained from a silicone resin heat-resistant paint is applied to a portion that is assumed to be exposed to a high temperature of 150 ° C. or higher.
Regarding such a silicone resin heat-resistant paint, Patent Document 1 discloses a composition capable of forming a coating film having anticorrosive properties even after being exposed to a high temperature of 500 ° C. Document 2 discloses a composition capable of forming a coating film having a dry film thickness of 100 to 400 μm by two or more times of overcoating, and Patent Document 3 discloses a composition of 5 to 30 ° C. or 40 ° C. Compositions that can be cured in a range and that can form a coating film having corrosion resistance and heat resistance are disclosed.

JP 2003-213210 A JP-A-11-279488 JP-T 2009-522388

  As described above, a heat-resistant coating composition capable of forming a coating film having a dry film thickness of 100 to 400 μm, and a coating film having corrosion resistance and heat resistance can be formed even when the coating film is formed at room temperature. Although a coating composition and a heat-resistant coating composition capable of forming a coating film having anticorrosion properties even after being exposed to a high temperature of 500 ° C. have been known, all of Patent Documents 1 to 3 are dried. A film with a thickness of 100 μm or more can be formed, and a film with excellent anticorrosion properties can be formed even when the film is formed under normal environmental temperature (normal temperature). A heat resistant coating composition capable of forming a coating film having a heat resistance of 600 ° C. or higher is not disclosed.

When the heat-resistant coating film formed on the outer surface of a pipe such as a plant structure exposed to an ultra-high temperature of 600 ° C. or more is a thick film, the heat-resistant coating film is subjected to repeated high-temperature environments and temperature changes. Blisters and cracks are likely to occur. More specifically, when the heat-resistant coating film is exposed to a high temperature, volatilization of the residual solvent in the coating film, and swelling due to gas generated by reaction and decomposition of the silicone resin component constituting the coating film, In addition, cracks may be caused due to an increase in internal stress of the coating film due to reaction or decomposition of the silicone resin component. Since these coating film defects are particularly likely to occur when applied to a thick film, the film thickness of a heat-resistant coating film obtained from a conventional silicone resin heat-resistant paint is usually less than 80 μm, and is typically 100 μm. It was difficult to achieve the above thick film coating specifications.
However, CUI has become a major maintenance problem in piping of plant structures and the like, and with respect to the severe corrosive environment, the above-described thin film of less than 80 μm cannot maintain long-term corrosion resistance. I found it impossible.

In addition, when using a conventional silicone resin heat-resistant paint, it is understood that a coating film having sufficient anti-corrosion properties such as anticorrosion cannot be obtained unless it is heated and dried (baked) under certain conditions. It was. However, since the plant structure is a large structure, when the existing structure is repaired, it is often difficult to heat and dry (bake) itself. In addition, when a heat-resistant coating film is formed on each member such as a steel pipe during construction of a plant structure, it can be dried by heating (baking), but the increase in the number of processes and the energy for heating The manufacturing cost increases due to such factors. Accordingly, there has been a demand for a paint capable of forming a heat-resistant coating film having sufficient coating performance such as anticorrosion properties required for plant structures even when the coating film is formed by drying at room temperature (5 to 40 ° C.).
Furthermore, since plant structures have various temperature environments depending on the operating conditions, it is necessary to select an anticorrosion coating (heat-resistant coating) and coating specifications that can withstand the environment, but in construction management and equipment repair, The management is complicated.

The present invention has been made in view of the above-mentioned problems, and a coating film exhibiting excellent anticorrosion properties in severe corrosive environments such as “under a heat insulating material” without performing drying by heating when forming the coating film. A heat-resistant coating composition capable of forming a film is provided.
Further, the present invention provides a heat resistant coating composition capable of forming a coating film that can maintain sufficient heat resistance, corrosion resistance and adhesion to a substrate even when exposed to various temperatures.

As a result of the inventor's intensive studies on a method for solving the above-mentioned problems, the inventors have found that the following problems can be solved by the following configurations, and have completed the present invention.
A configuration example of the present invention is as follows.

  <1> A heat-resistant coating composition containing a siloxane-based binder (A), mica (B), and mica-like iron oxide (C).

<2> The heat resistant coating composition according to <1>, wherein a mass ratio of the mica (B) to the mica-like iron oxide (C) is in a range of 90:10 to 30:70.
<3> The heat resistant coating composition according to <1> or <2>, wherein the pigment volume concentration (PVC) of the heat resistant coating composition is 30 to 50%.

<4> The siloxane-based binder (A) includes a silicone resin (A1) having a weight average molecular weight (Mw) of 15,000 or more and 300,000 or less and a silicone oligomer (A2) having a weight average molecular weight of less than 15,000. The heat-resistant paint composition according to any one of <1> to <3>, comprising at least one selected from the group.
<5> The heat-resistant coating composition according to <4>, wherein the siloxane binder (A) includes ethyl silicate (A3).

<6> The heat resistant coating composition according to any one of <1> to <5>, further comprising an amide thixotropic agent (D).
<7> The heat resistant paint composition according to any one of <1> to <6>, further comprising a rust preventive pigment (E).

<8> A heat-resistant coating film formed from the heat-resistant coating composition according to any one of <1> to <7>.
<9> A substrate with a heat-resistant coating film comprising the substrate and the heat-resistant coating film according to <8>.
<10> The substrate with a heat-resistant coating film according to <9>, wherein the substrate is a plant structure.

<11> A method for producing a substrate with a heat-resistant coating film, comprising the following steps [1] and [2].
[1] A step of applying a heat resistant coating composition according to any one of <1> to <7> to a substrate. [2] A heat resistant coating composition is dried by drying the heat resistant coating composition coated on the substrate. Forming process

  According to the present invention, even if it is not heated and dried when forming a coating film, in a severe corrosive environment such as “under the heat insulating material”, it exhibits excellent anticorrosive properties over a long period of time, and a base material such as stainless steel Heat-resistant paint composition capable of forming a coating film that can maintain sufficient heat resistance, corrosion resistance and adhesion to a substrate even under a wide range of temperatures including ultra-high temperatures exceeding 600 ° C. Things can be provided.

FIG. 1: is a schematic plan view of the test piece which put the scribe used for corrosion-proof evaluation in an Example.

≪Heat resistant paint composition≫
A heat-resistant coating composition according to an embodiment of the present invention (hereinafter also simply referred to as “the present composition”) contains a siloxane-based binder (A), mica (B), and mica-like iron oxide (C).
Since the present composition contains these components (A) to (C), according to the present composition, the dry film thickness is 100 μm or more and is exposed to a high temperature environment exceeding 600 ° C. After that, it is possible to maintain the anticorrosion property and the adhesion to the substrate, and it is possible to obtain a heat-resistant coating film having sufficient anticorrosion property even when formed by drying at room temperature.
In addition, according to the present composition, stainless steel (e.g., SUS304, which is applied particularly when exposed to a high temperature environment of 400 ° C. or higher, which has a large linear expansion coefficient compared to carbon steel). A heat-resistant coating film having good adhesion to SUS316L or the like can be formed.
For this reason, this composition is preferably used for the outer surface of piping for plant structures where operation under various temperature conditions is assumed and heat insulation is installed, and is suitable for suppressing CUI. It is suitably used as a paint capable of forming an anticorrosive coating film.

  This composition will not be restrict | limited especially if it contains component (A)-(C), If desired, in the range which does not impair the effect of this invention, an amide type thixotropic agent (D) and a rust preventive pigment (E). As other components, additives other than components (B), (C) and (E), pigment dispersants, antifoaming agents, anti-sagging / anti-settling agents other than component (D), dehydrating agents, An organic solvent and a curing catalyst may be included.

<Siloxane binder (A)>
The siloxane-based binder (A) is not particularly limited as long as it is a compound having a siloxane bond. The siloxane-based binder (A) is also a siloxane-based binder.
In this composition, since the siloxane-based binder (A) is used as a binder, a heat-resistant coating film having particularly excellent heat resistance can be obtained.
The siloxane-based binder (A) contained in the composition may be one type or two or more types.

The siloxane-based binder (A) has, for example, a reactive group in the molecule through a siloxane bond, and the reactive groups react with each other to form a high molecular weight or three-dimensional crosslinked structure. A compound that cures can be mentioned.
Examples of the reaction include a condensation reaction and an addition reaction, and examples of the condensation reaction include a dehydration reaction and a dealcoholization reaction.

The siloxane-based binder (A) is preferably, for example, a compound represented by the following formula (I), preferably contains the following silicone resin (A1) and / or silicone oligomer (A2), and further ethyl silicate. (A3) can be contained.
In particular, the composition preferably contains a silicone resin (A1) as the siloxane binder (A) from the viewpoint that a heat-resistant coating film that is superior in heat resistance and corrosion resistance can be obtained. For the purpose of adjusting the membrane performance, it is more preferable to use it in combination with a silicone oligomer (A2) having a lower weight average molecular weight, and further it is possible to use ethyl silicate (A3) in combination.
The siloxane-based binder (A) may be linear or branched.

(In formula (I), each R ¹ independently represents an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms, and each R ² independently represents An alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 8 carbon atoms, or a hydrogen atom, and n represents a repeating number, so that the weight average molecular weight of the siloxane-based binder is in the range of 200 to 300,000. Selected.)

Examples of the alkyl group having 1 to 8 carbon atoms in R ¹ and R ² include a methyl group, an ethyl group, a propyl group, a butyl group, and a pentyl group.
The aryl group having 6 to 8 carbon atoms in R ¹ and R ² may be a group having a substituent such as an alkyl group on the aromatic ring, and examples thereof include a phenyl group, a methylphenyl group, and a dimethylphenyl group. It is done.
Examples of the alkoxy group having 1 to 8 carbon atoms in R ¹ include a methoxy group, an ethoxy group, a propoxy group, and a phenoxy group.

The weight average molecular weight (hereinafter also simply referred to as “Mw”) in terms of standard polystyrene measured by the GPC (gel permeation chromatography) method of the siloxane-based binder (A) is preferably 200 to 300,000. More preferably, it is 400-200,000.
Specifically, the Mw can be measured by the method described in the Examples below.

  The content of the siloxane-based binder (A) is preferably 20 to 45 masses with respect to 100 mass% of the solid content of the present composition from the viewpoint that a heat-resistant coating film that is superior in corrosion resistance and heat resistance can be obtained. %, More preferably 25 to 43% by mass, particularly preferably 28 to 38% by mass.

<Silicone resin (A1)>
The silicone resin (A1) is not particularly limited as long as it is a compound other than ethyl silicate (A3) described later, but is preferably a compound represented by the formula (I), and R ¹ in the formula (I) is A compound having a methyl group, an ethyl group, a propyl group or a phenyl group is more preferable, and a compound in which R ² in the formula (I) is a methyl group, an ethyl group, a phenyl group or a hydrogen atom is more preferable.
1 type may be sufficient as the silicone resin (A1) contained in this composition, and 2 or more types may be sufficient as it.

  The silicone resin (A1) is preferably a heat-resistant resin such as methyl silicone resin, methylphenyl silicone resin, and the following dimethylsiloxane unit (a1), diphenylsiloxane unit (a2), monomethylsiloxane unit (a3). ), One or more structural units selected from the group consisting of a monopropylsiloxane unit (a4) and a monophenylsiloxane unit (a5).

(In formulas (a1) to (a5), “—” in Si—O— that is bonded to O and not bonded to Si represents a bond, and Si—O— is not necessarily Si—O—CH. ₃ is not shown.)

The Mw of the silicone resin (A1) is 15,000 or more and 300,000 or less, preferably 18,000 or more and 200,000, from the viewpoint that a heat-resistant coating film having excellent heat resistance and corrosion resistance can be obtained. It is as follows.
Silicone resin (A1) having an Mw larger than the above range has a high viscosity. Therefore, in consideration of handleability, in order to reduce the viscosity of the present composition containing such a silicone resin (A1), dilution with an organic solvent or the like is required. Is often required. As a result, the solvent content in the present composition increases, and VOC (Volatile Organic Compounds / volatile organic compounds) in the present composition may not be reduced.

  The silicone resin (A1) may be synthesized by a conventionally known synthesis method or may be a commercially available product. Examples of the commercially available products include “SILRES REN60”, “SILRES REN80” (both manufactured by Asahi Kasei Wacker Silicone Co., Ltd.), and “SILIKOPEN P80 / X” (manufactured by Evonik).

  The content of the silicone resin (A1) is preferably 10 to 40% by mass with respect to 100% by mass of the solid content of the present composition from the standpoint that a heat-resistant coating film having superior corrosion resistance and heat resistance can be obtained. More preferably, it is 12-35 mass%, Most preferably, it is 12-33 mass%.

<Silicone oligomer (A2)>
The silicone oligomer (A2) is not particularly limited as long as it is a compound other than the ethyl silicate (A3) described later, but is preferably a compound having a structure similar to the structure given in the column of the silicone resin (A1). .
Mw of the silicone oligomer (A2) is less than 15,000, preferably 400 to 12,000.
1 type may be sufficient as the silicone oligomer (A2) contained in this composition, and 2 or more types may be sufficient as it.

  The silicone oligomer (A2) may be synthesized by a conventionally known synthesis method or may be a commercially available product. Examples of the commercially available products include “SILRES MSE100” (manufactured by Asahi Kasei Wacker Silicone Co., Ltd.) and “KR-401N” (manufactured by Shin-Etsu Chemical Co., Ltd.).

  The content of the silicone oligomer (A2) is preferably 0 to 40% by mass with respect to 100% by mass of the solid content of the present composition from the viewpoint that a heat-resistant coating film that is superior in corrosion resistance and heat resistance can be obtained. The amount is more preferably 2 to 25% by mass, particularly preferably 3 to 10% by mass.

<Ethyl silicate (A3)>
The ethyl silicate (A3) is a compound composed of siloxane having an ethoxy group and is represented by the following formula (II).
1 type may be sufficient as the ethyl silicate (A3) contained in this composition, and 2 or more types may be sufficient as it.

(In formula (II), n is 1-10.)

  The ethyl silicate (A3) may be synthesized by a conventionally known synthesis method or may be a commercially available product. Examples of the commercially available products include “ethyl silicate 40” (manufactured by Colcoat Co., Ltd.) and “Wacker Silicate TES 40WN” (manufactured by Asahi Kasei Wacker Silicone Co., Ltd.) which are oligomers having a molecular weight distribution centered on a pentamer. Is mentioned.

  The content of the ethyl silicate (A3) is based on 100% by mass of the solid content of the present composition in terms of coating workability, cost reduction, and the ability to obtain a coating composition with excellent dehydrating effect during storage. The content is preferably 0 to 20% by mass, more preferably 0 to 10% by mass.

  The ratio (A1 + A2: A3) of the total content of the silicone resin (A1) and the silicone oligomer (A2) and the content of ethylsilicate (A3) in this composition is excellent in heat resistance and anticorrosion properties. Is preferably 100: 0 to 90:10 from the standpoint that it can be obtained.

  In addition, the ratio (A1: A2 + A3) of the content of the silicone resin (A1) and the total content of the silicone oligomer (A2) and the ethyl silicate (A3) in this composition is excellent in heat resistance and corrosion resistance. From the point that a coating film can be obtained, it is preferably 90:10 to 30:70, and more preferably 90:10 to 40:60.

<Mica (B)>
The mica (B) is not particularly limited as long as it is a scaly (flat) mica.
In the system using the siloxane-based binder (A), the present composition can be used for the first time by using both mica (B) and mica-like iron oxide (C), without heating and drying when forming a coating film. Even if the formed coating is a thick film of 100 μm or more, exposed to various temperatures including high temperatures of 600 ° C. or higher, even in severe corrosive environments such as “under a heat insulating material”, over a long period of time. A heat-resistant coating film excellent in heat resistance, corrosion resistance, and adhesion to a substrate can be obtained.
The mica (B) contained in the composition may be one type or two or more types.

The mica (B) is classified into white mica (Muscovite), gold mica (Phologopite) and the like.
Although it does not specifically limit as said mica (B), White mica is preferable from the point of being able to obtain the heat-resistant coating film which is excellent by the adhesiveness with respect to a base material, especially stainless steel.

  The average particle diameter (median diameter) of the mica (B) measured using a laser diffraction particle size distribution measuring apparatus (SALD-2200, manufactured by Shimadzu Corporation) is determined by the adhesion to the base material, particularly the steel pipe. From the point that an excellent heat-resistant coating film can be obtained, it is preferably 25 to 80 μm, more preferably 35 to 60 μm.

The aspect ratio (average particle diameter / average particle thickness) of the mica (B) is preferably from 10 to 150, more preferably from the viewpoint of obtaining a heat-resistant coating film that is superior in adhesion to the substrate. Is 20-100.
The average thickness of the particles was observed from the horizontal direction with respect to the main surface of the mica (B) using a scanning electron microscope (SEM), for example, “XL-30” (manufactured by Philips). It can be calculated as an average thickness of several hundred pigment particles.

  The mica (B) may be a commercially available product, and examples of the commercially available product include “Mica powder 100 mesh” (manufactured by Fukuoka Talc Industrial Co., Ltd., average particle size: 41 μm).

  The content of the mica (B) is preferably 15 to 60% by mass with respect to 100% by mass of the solid content of the present composition from the viewpoint that a heat-resistant coating film that is superior in adhesion and heat resistance can be obtained. More preferably, it is 20-40 mass%.

<Mica-like iron oxide (C)>
The mica-like iron oxide (Micacous Iron Oxide (MIO)) is a pigment made of scaly (flat) or hexagonal plate-like iron oxide, and may be a pigment obtained by crushing and classifying natural minerals, It may be a pigment synthesized by a conventionally known method such as hydrothermal treatment.
The mica-like iron oxide (C) contained in the composition may be one type or two or more types.

The mica-like iron oxide (C) can be measured for an average particle diameter (median diameter) and an average thickness of particles by the same method as that described in the column of the mica (B). Is preferably from 15 to 45 μm, more preferably from 20 to 35 μm, from the viewpoint that a heat-resistant coating film having better anticorrosion properties can be obtained.
Moreover, the aspect ratio (average particle diameter / average particle thickness) of the mica-like iron oxide (C) is preferably 5 to 100 from the standpoint that a heat-resistant coating film having better adhesion to the substrate can be obtained. More preferably, it is 10-50.

  The mica-like iron oxide (C) may be a commercially available product, and examples of the commercially available product include “MIOX 325 mesh” (manufactured by Anhui Tongling Maceous Iron Oxide Factory, average particle size: 26 μm).

  The content of the mica-like iron oxide (C) is preferably 10 to 40% by mass with respect to 100% by mass of the solid content of the present composition from the viewpoint that a heat-resistant coating film that is superior in corrosion resistance can be obtained. More preferably, it is 20-38 mass%, Most preferably, it is 27-35 mass%.

  In the present composition, the mica (B), the mica-like iron oxide (C), and the like can be obtained in that the coating film properties after the high temperature heat test and the corrosion resistance when cured at room temperature can be obtained. The mass ratio is preferably 90:10 to 30:70, more preferably 60:40 to 40:60.

<Amide-based thixotropic agent (D)>
The composition contains an amide thixotropic agent (D) and is excellent in thixotropic properties. According to the composition, a thick film having a dry film thickness of 100 μm or more can be formed by one coating, Even if the target substrate is stainless steel such as SUS304, SUS316L, etc., it has excellent adhesion to the substrate and even after being exposed to a high temperature environment of 400 ° C. or higher. The heat-resistant coating film to maintain can be obtained.
1 type may be sufficient as the amide type thixotropic agent (D) contained in this composition, and 2 or more types may be sufficient as it.

  Although it does not restrict | limit especially as said amide type thixotropic agent (D), For example, the thixotropic agent synthesize | combined from a vegetable oil fatty acid and an amine is mentioned.

  The amide type thixotropic agent (D) may be synthesized by a conventionally known method or may be a commercially available product. Examples of the commercially available products include “DISPARON A630-20X”, “DISPARON 6650” (both manufactured by Enomoto Kasei Co., Ltd.), “AS-A T-250F” (manufactured by Ito Oil Co., Ltd.), “ "Fronon RCM-300TL" (manufactured by Kyoeisha Chemical Co., Ltd.).

  The content of the amide type thixotropic agent (D) is preferably based on 100% by mass of the solid content of the composition from the viewpoint that the effect of the amide type thixotropic agent (D) is more exhibited. Is 0.3 to 5 mass%, more preferably 1 to 2.5 mass%.

<Rust prevention pigment (E)>
The present composition contains a rust preventive pigment (E), so that a heat-resistant coating film having excellent corrosion resistance can be obtained even when cured and dried at room temperature.
The antirust pigment (E) contained in the present composition may be one type or two or more types.

  The rust preventive pigment (E) is not particularly limited, and conventionally known rust preventive pigments can be mentioned. Preferred are lead / chromium-free rust preventive pigments, more preferred are phosphate-based rust preventive pigments, and particularly preferred are zinc phosphate-based rust preventive pigments and aluminum phosphate-based rust preventive pigments.

  The rust preventive pigment (E) may be a commercially available product, and examples of the commercially available product include “LF Bowsey ZP-N” and “LF Bowsey PM-303W” (both manufactured by Kikuchi Color Co., Ltd.). .

  The content of the rust preventive pigment (E) is preferably 1 to 10 with respect to 100% by mass of the solid content of the present composition from the viewpoint that the effect of the rust preventive pigment (E) is more exhibited. It is 3 mass%, More preferably, it is 3-8 mass%.

<Other ingredients>
If necessary, the present composition may contain a pigment (colored pigment and extender pigment) other than mica (B), mica-like iron oxide (C) and rust preventive pigment (E), and a pigment dispersant, as long as the effects of the present invention are not impaired. Additives such as anti-sagging and anti-settling agents other than antifoaming agents and amide type thixotropic agents (D), additives such as dehydrating agents, organic solvents, curing catalysts and the like may be included.
Each of these other components may be one kind or two or more kinds.

(Color pigment)
Although it does not restrict | limit especially as said coloring pigment, It is preferable that it is a coloring pigment which has heat resistance, for example, Pigment Black 28 (Copper black black spinel), aluminum flakes, stainless steel flakes, titanium white, carbon black, and a valve handle are mentioned. It is done.
Examples of commercially available color pigments include “CFP-4010BK” (MnO ₂ —Fe ₂ O ₃ —CuO—Co ₃ O ₄ , manufactured by Okuno Pharmaceutical Co., Ltd.), aluminum, which is a chromium-free black inorganic pigment. “Al-Paste 0100M-C70” (manufactured by Toyo Aluminum Co., Ltd.), which is a paste, can be mentioned.

<External pigment>
The extender is not particularly limited, but is preferably an extender having heat resistance, and examples thereof include talc, silica, potassium feldspar, barium sulfate, zinc oxide, calcium carbonate, kaolin, and aluminum oxide.

<Pigment dispersant>
Although it does not restrict | limit especially as said pigment dispersant, It is preferable that it is a dispersant which can disperse | distribute the pigment in this composition uniformly and can prepare a stable dispersion.
The pigment dispersant may be a commercially available product, and examples of the commercially available product include “Disperbyk-180” and “Disperbyk-2022” (both manufactured by Big Chemie Japan Co., Ltd.).

<Antifoaming agent>
Although it does not restrict | limit especially as said antifoamer, It is the material which can suppress generation | occurrence | production of foam at the time of manufacture of this composition or a coating, or the material which can break the foam generated in this composition. It is preferable.
The antifoaming agent may be a commercially available product, and examples of the commercially available product include “BYK-320”, “BYK-066N”, and “BYK-1790” (all manufactured by Big Chemie Japan Co., Ltd.). .

<Anti-sagging and anti-settling agent>
The anti-sagging / anti-settling agent is not particularly limited. However, the anti-sagging property of the coating composition at the time of coating or after coating, or a material that can suppress the pigment settling of the composition and improve its storage stability. It is preferable that the material be capable of improving.

  Examples of the anti-sagging and anti-settling agent include hydrogenated castor oil-based thixotropic agents, organic thixotropic agents such as polyethylene oxide thixotropic agents, clay minerals such as bentonite, and inorganic thixotropic agents such as synthetic fine silica. Among these, clay minerals such as polyethylene oxide thixotropic agent, synthetic fine silica and bentonite are preferable.

  The sagging and anti-settling agent may be a commercially available product, and examples of the commercially available product include “Bentone 38” (Elementis Specialties Inc.), which is an organically modified bentonite viscosity modifier (hectorite / quaternary amine). ), “Aerosil R972” (produced by Nippon Aerosil Co., Ltd.), a silicon dioxide thixotropic agent, and “ASAD 120” (produced by Ito Oil Co., Ltd.), a polyethylene thixotropic agent. Can be mentioned.

  The content of the anti-sagging / anti-settling agent is preferably 0.1 to 10% by mass with respect to 100% by mass of the solid content of the present composition.

<Dehydrating agent>
The dehydrating agent is not particularly limited as long as it has a dehydrating effect, but is preferably a material that can suppress a decrease in storage stability of the composition due to excessive moisture.
Examples of such a dehydrating agent include anhydrous gypsum and vinyltrimethoxysilane.

<Organic solvent>
When this composition is applied to a plant structure in a high temperature state during plant operation, especially a base material such as an outer surface of a pipe, the organic solvent easily evaporates due to the heat of the base material surface, and a good coating film is formed. It tends to be difficult. For this reason, it is preferable that the organic solvent contains an organic solvent having a relatively high boiling point. Examples of such high boiling point organic solvents include mineral spirits and isopropyl alcohol. In addition, solvents commonly used in paints can also be applied. Examples of such an organic solvent include xylene, toluene, and n-butyl alcohol.

<Curing catalyst>
The curing catalyst is not particularly limited, but is preferably a material having an effect of promoting the crosslinking reaction of the siloxane binder (A). For example, amino silane, titanium alkoxide, titanium chelate, aluminum / zinc or other metal soap, phosphorus Examples include acids and phosphate esters. Among these, metal soaps such as aluminum and zinc are preferable because they tend to easily make the composition into a one-pack type.

  The curing catalyst may be a commercially available product. Examples of the commercially available product include “D-220” and “X-40-2309A” that are phosphoric acid-based curing catalysts, and “D-25” that is a titanium-based curing catalyst. , “D-20”, “DX-175”, “DX-9740”, “CAT-AC” which is an aluminum curing catalyst, “KP-390” which is an amine curing catalyst (n of amino group-containing alkoxysilane) -Butanol solution), "D-15" and "D-31" (both manufactured by Shin-Etsu Chemical Co., Ltd.) which are zinc-based curing catalysts.

<Heat resistant paint composition>
The pigment volume concentration (PVC: Pigment Volume Concentration) of the present composition is preferably from the point that it is excellent in corrosion resistance and can obtain a heat-resistant coating film that is excellent in adhesion to the base material of the coating film after heat drying. 30 to 50%, more preferably 35 to 45%.
When PVC is less than the above range, the corrosion resistance of the formed heat-resistant coating film tends to decrease, and the adhesion of the coating film after heat drying to the substrate also tends to decrease. Moreover, when PVC exceeds the said range, it exists in the tendency for the corrosion resistance of the heat-resistant coating film formed to fall.

The PVC refers to the total volume concentration of the pigment relative to the volume of the solid content (nonvolatile content) in the composition. Specifically, PVC can be obtained from the following equation.
PVC [%] = total volume of all pigments in the composition × 100 / volume of solids in the composition

  In addition, in this specification, solid content of this composition means the heating residue obtained according to JISK5601-1-2 (heating temperature: 125 degreeC, heating time: 60 minutes). The solid content of the composition can also be calculated as an amount excluding the solvent and the organic solvent in the raw material used.

The volume of the solid content in the composition can be calculated from the mass and the true density of the solid content of the composition. The mass and true density of the solid content may be measured values or values calculated from the raw materials used.
The volume of the pigment can be calculated from the mass and true density of the pigment used. The mass and true density of the pigment may be measured values or values calculated from the raw materials used. For example, it can be calculated by separating the pigment and other components from the solid content of the present composition and measuring the mass and true density of the separated pigment.

  The present composition is preferably a one-component coating composition from the viewpoint that it becomes a composition having excellent coating workability, but the two-component type in which the curing catalyst is mixed and stirred immediately before the start of the coating operation. It can also be set as the coating composition of this.

≪Heat-resistant coating film and substrate with heat-resistant coating film≫
The heat-resistant coating film according to one embodiment of the present invention (hereinafter also referred to as “the present heat-resistant coating film”) is formed from the above-described composition, and the substrate with a heat-resistant coating film according to one embodiment of the present invention is It is a laminated body containing this heat-resistant coating film and a base material.

  The substrate is not particularly limited. For example, a steel substrate (iron, steel, alloy iron, carbon steel, alloy steel, etc.), a metal substrate made of non-ferrous metal (stainless steel, aluminum, etc.), and a surface with a shop primer or the like. Examples include coated metal substrates. In addition, examples of the base material include plant structures, land structures, marine structures, ships, and the like. From the standpoint that the effects of the present invention are more exerted, the plant structure is preferably a plant structure. Among the structures, plant piping is more preferable. In particular, the base material is more preferably carbon steel used for plant piping, ships, marine structures, or stainless steel such as SUS304, SUS316L, which is suitably used for parts requiring cold resistance and heat resistance.

The film thickness of the heat-resistant coating film is not particularly limited as long as it has a thickness that can prevent corrosion of the substrate, but is preferably 100 to 400 μm, more preferably 150 to 280 μm.
Since the present composition is used, even if a coating film having such a film thickness is formed on the substrate, the coating film is unlikely to swell or crack, and in particular, at a high temperature of 400 ° C. or higher or a rapid temperature change. Even when exposed, since it is difficult for blisters and cracks to occur, the substrate can be anticorrosive over a long period of time.
In addition, considering the anticorrosive properties, a thicker film state is desirable, but in the case of an excessively thick film, the residual solvent contained in the coating film volatilizes due to heating, or the coating film swells, There is a tendency that the internal stress of the coating film increases due to the structural change caused by the reaction or decomposition of the siloxane-based binder (A) or a component derived from the binder, and cracks and peeling easily occur.

The present heat-resistant coating film is formed from the above-described composition, and specifically can be produced through steps including the following steps [1] and [2].
[1] A step of coating the present composition on a substrate [2] A step of drying the heat-resistant coating composition coated on the substrate to form a heat-resistant coating film

Furthermore, this method can form the heat-resistant coating film which is excellent in corrosion resistance and heat resistance by including the following step [3].
[3] A step of heating the coating film obtained in the step [2] at 150 to 250 ° C.

<Process [1]>
The method for coating the composition on the substrate is not particularly limited, and any conventionally known method can be used without limitation, and generally used airless spray coating, air spray coating, brush coating, roller coating, and the like are preferable. Spray coating is preferred because it is excellent in workability, productivity, etc., can be easily applied to a large-area substrate, and can exhibit the effects of the present invention more.
When the present composition is a two-component composition, the main agent component and the curing accelerating component (component containing the curing catalyst) may be mixed immediately before coating and spray coating or the like may be performed.

The spray coating conditions may be appropriately adjusted according to the thickness of the heat-resistant coating film to be formed. For example, in the case of airless spraying, the primary (air) pressure: about 0.4 to 0.8 MPa, the secondary ( The coating conditions may be set to (paint) pressure: about 10 to 26 MPa, gun moving speed: about 50 to 120 cm / second.
The viscosity of the composition used at that time is adjusted with a thinner. The viscosity is 1.8 at 23 ° C. when measured with a B-type viscometer (“TVB-10M, manufactured by Toki Sangyo Co., Ltd.). The thinner is preferably an organic solvent that can dissolve or disperse the components in the composition, for example, aromatic hydrocarbon solvents such as toluene and xylene, minerals, and the like. Examples thereof include aliphatic hydrocarbon solvents such as spirit and cyclohexane, and alcohol solvents such as n-butanol and isopropanol, etc. The thinner used may be one kind or two or more kinds.

  When this composition is applied to plant piping, etc., it is possible to apply it to relatively high temperature piping without stopping the operation of the plant. It becomes solid before it becomes a smooth coating film, and it becomes easy to be painted in dust. For the purpose of suppressing this, a high boiling point solvent can be used as the thinner.

  In order to remove rust, fats and oils, moisture, dust, salt, etc. on the base material when coating this composition on the base material, and to improve the adhesion of the resulting heat-resistant coating film to the base material If necessary, the surface of the base material is preferably subjected to treatment (for example, blast treatment (ISO8501-1 Sa2 1/2), treatment for removing oil and dust by degreasing) and the like. The base material may be coated with a shop primer or the like for the purpose of primary rust prevention.

<Step [2]>
The present composition can be dried and cured at room temperature. Thus, even when dried and cured at room temperature, a heat-resistant coating film having excellent heat resistance and corrosion resistance can be obtained. Further, if desired, drying may be performed under heating in order to shorten the drying time.
Although it does not restrict | limit especially as said drying conditions, What is necessary is just to set suitably according to this composition, a base material, a coating place, etc., Preferably drying temperature is 5-40 degreeC, More preferably, it is 10-30 degreeC. The drying time is preferably 18 hours to 14 days, more preferably 24 hours to 7 days.

<Step [3]>
By performing the step [3], a heat-resistant coating film that is physically and chemically more resistant can be formed. That is, it is possible to form a heat-resistant coating film having higher coating film hardness or superior corrosion resistance.
Although it does not restrict | limit especially as heating conditions in the said process [3], Heating temperature becomes like this. Preferably it is 150-250 degreeC, Heating time is preferably 10 minutes-3 hours, More preferably, it is 30 minutes-1 hour. .

As a method of forming the heat-resistant coating film having the above-mentioned thickness, a coating film having a desired film thickness may be formed by one coating, or a desired film thickness may be formed by two or more coatings (two or more coatings). A coating film may be formed. In consideration of the film thickness management and the residual solvent in the coating film, it is preferable to form a coating film having a desired film thickness by two or more coatings.
The two coatings (two coatings) are steps [1] and [2], and if necessary, after performing step [3], the steps [1] and [2] In addition, it means a method of performing the step [3] as necessary, and the coating three times or more means a method of repeating a series of steps.

  When the coating film is formed by two or more coatings, for example, the hue of the paint / coating film to be applied for the first time is preferably different from the hue of the coating / coating film to be applied next. This is a measure for facilitating determination of forgetting to paint or insufficient film thickness in the painting operation. Further, in order to finish the final hue on the outer surface to a specified hue, a top coat may be applied.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not restrict | limited by these.

<Weight average molecular weight of siloxane-based binder (A)>
The weight average molecular weight (Mw) of the siloxane-based binder (A) was measured by the GPC method under the following conditions.
・ GPC conditions ・ Apparatus: “Alliance 2695” (manufactured by Waters)
Column: Connects one "TSKgel SuperH4000" and two "TSKgel SuperH2000" (both manufactured by Tosoh Corporation, 6 mm inner diameter x 15 cm length)
Eluent: Tetrahydrofuran 99% (Stabilized with BHT)
・ Flow rate: 0.6ml / min
Detector: “RI-104” (manufactured by Shodex)
-Column temperature chamber: 40 ° C
・ Standard material: Standard polystyrene ・ Sample preparation method: Weigh the sample into a sample tube and add tetrahydrofuran to dilute it about 100 times

[Example 1]
Place 9.7 parts by mass of New Solvent A, 2 parts by mass of n-butanol, 6.05 parts by mass of xylene, 0.2 parts by mass of Disperbyk-180 and 0.05 parts by mass of BYK-320 in a container, and further SILRES REN80 30. 3 parts by mass, 1 part by mass of Disparon 6650, and 4 parts by mass of LF Bowsey ZP-N were added and stirred with a high-speed disper and dispersed uniformly.
To the obtained mixture, 36.9 parts by mass of mica powder 100 mesh was added and stirred, and the temperature of the mixture was raised to 58 ° C. by the heat generated by the stirring.
Furthermore, after adding 8.3 parts by mass of MIOX 325 mesh, stirring and uniformly dispersing, the mixture was cooled to 30 ° C. or less, 1.5 parts by mass of D-15 being added, stirring and uniformly dispersing, and a 60 mesh nylon mesh. And a coating composition was prepared.

[Examples 2 to 14 and Comparative Examples 1 to 3]
A coating composition was prepared in the same manner as in Example 1 except that the raw materials shown in Tables 2 to 5 were used in the amounts shown in the table. In addition, the numerical value described in the column of the raw material of Tables 2-5 shows a mass part.
Moreover, the detail of each raw material of Tables 2-5 is as showing in Table 1.
In addition, solid content (mass%) of each component in Table 1 is a manufacturer catalog value.

<Evaluation of physical properties of coating film>
(1) Unheated test Xylene was used so that the viscosity of the coating compositions obtained in Examples and Comparative Examples was 2.0 Pa · s measured at 23 ° C. using the B-type viscometer. It adjusted using.
The viscosity-adjusted coating composition was applied on SS400 sandblasted steel plate (equivalent to ISO8501-1 Sa2 1/2) using a film applicator with a gap of 700 μm so that the dry film thickness was 250 μm.
Then, the test piece (base material with a coating film) was created by drying the coating composition apply | coated on the steel plate at 23 degreeC for 7 days.

The obtained test piece was evaluated according to the following evaluation criteria.
5: Good appearance of coating film without cracks, peeling, etc. Good curing and drying properties.
4: There is no crack, no peeling, etc., and the appearance of the coating film is good, but adhesion remains on the coating film surface.
3: When a magnifying glass is used, cracks and the like are observed on the coating film surface.
2: Even if a magnifying glass is not used, a crack or the like is observed in a part of the coating film.
1: Generation | occurrence | production of a crack and peeling is recognized over the whole coating film.

(2) HRT (Heat Resistant Test)
The test piece obtained in the same manner as in the above (1) unheated test was put in a muffle furnace, heated at 650 ° C. for 4 hours, and then allowed to cool. Were evaluated according to the same evaluation criteria.

(3) Heat Shock Test (1) A test piece obtained in the same manner as in the unheated test was placed in an oven, heated at 400 ° C. for 8 hours, then removed from the oven, immediately immersed in ice water for 10 seconds, and rapidly cooled. . Thereafter, the test piece was taken out from the ice water, and after removing water droplets adhering to the test piece with a paper waste, the test piece was left at room temperature overnight. After this heating and quenching were further performed twice (heating and quenching three times in total), the obtained test pieces were evaluated according to the same evaluation criteria as in the (1) unheated test.

(4) HRT (SUS base material)
A test piece was prepared in the same manner as in the (1) unheated test, except that a SUS304 sand sweep (ISO8501-1 Sa1 equivalent) plate was used instead of the steel plate.
Except for using the obtained test piece, the test piece obtained by heating and allowing to cool was evaluated in accordance with the following evaluation criteria in the same manner as in (2) HRT.
5: Good appearance of coating film without cracks, peeling, etc.
4: Peeling is recognized in a very small part (less than 5% in area) of the coating film.
3: Peeling is observed in a part of the coating film (5% or more and less than 20% by area).
2: Peeling is recognized in the coating film corresponding to an area of 20% to 50% of the entire coating film surface.
1: The entire surface of the coating film was peeled off or cracks were observed on the entire surface of the coating film.

<Evaluation of corrosion resistance>
Evaluation of anticorrosion is a scratch (scribe) having a depth to which a part of the steel plate is exposed at the position shown in FIG. 1 of each test piece after performing the coating film physical property evaluations (1) to (3). In addition, in order to eliminate the influence of the part not coated with the coating composition, the test piece was coated with an epoxy anticorrosive paint on the back and edge portions of the test piece. On the other hand, a salt spray test (35 ° C.) was conducted for 3 weeks and evaluated according to the following evaluation criteria.
5: Rust is not recognized in the evaluation target part.
4: Rusting is observed slightly (less than 1% in area) in the evaluation target part.
3: Rusting is observed in a part of the evaluation target part (1% or more and less than 5% in area).
2: Rust is observed in a part of the evaluation target part (5% or more in area).
1: The rusting accompanying peeling of a coating film or floating of a coating film is recognized.

Here, the “evaluation target part” refers to a part excluding the range of 1 cm from the end of the test piece in consideration of the influence of the epoxy anticorrosive paint.
In Tables 3, 4 and 5 below, “unheated test (general part)” means that the anticorrosion test was performed using the test piece after the (1) unheated test in the coating film property evaluation. Among the evaluation target parts, the general part shown in FIG. 1 (the part excluding the 1 cm range from the end of the test piece and the part excluding the 1 cm range from the scribe) was evaluated. It is a test.
“Unheated test (scribe part)” in the following Tables 2, 3, 4 and 5 means that the anticorrosion test was performed using the test piece after the (1) unheated test of the coating film property evaluation. In the test to evaluate the scribe portion shown in FIG. 1 (the portion excluding the range of 1 cm from the end of the test piece and the portion of the range of 1 cm from the scribe) in the evaluation target portion. is there.
In Table 5 below, “HRT (general part)” and “HRT (scribe part)” mean the anticorrosion using the test piece after performing (2) HRT (Heat Resistant Test) of the coating film physical property evaluation. This is a test conducted. “HRT (general part)” is a test that evaluates the general part shown in FIG. 1 among the evaluation target parts, and “HRT (scribe part)” evaluates the scribe part shown in FIG. 1 among the evaluation target parts. It was a test.
In addition, in the column of anticorrosiveness of Tables 3-5, the evaluation which does not describe "(General part)" or "(Scribe part)" makes both the general part and scribe part shown in FIG. 1 an evaluation object part. It is the result of evaluation.

Claims (11)

  A heat resistant coating composition containing a siloxane-based binder (A), mica (B) and mica-like iron oxide (C).   The heat-resistant paint composition according to claim 1, wherein a mass ratio of the mica (B) to the mica-like iron oxide (C) is in a range of 90:10 to 30:70.   The heat resistant paint composition according to claim 1 or 2, wherein the heat resistant paint composition has a pigment volume concentration (PVC) of 30 to 50%.   The siloxane binder (A) is selected from the group consisting of a silicone resin (A1) having a weight average molecular weight (Mw) of 15,000 or more and 300,000 or less and a silicone oligomer (A2) having a weight average molecular weight of less than 15,000. The heat-resistant paint composition according to any one of claims 1 to 3, comprising at least one of the above.   The heat-resistant coating composition according to claim 4, wherein the siloxane binder (A) comprises ethyl silicate (A3).   Furthermore, the heat-resistant coating material composition of any one of Claims 1-5 containing an amide type thixotropic agent (D).   Furthermore, the heat-resistant coating material composition of any one of Claims 1-6 containing a rust preventive pigment (E).   The heat-resistant coating film formed from the heat-resistant coating composition of any one of Claims 1-7.   A substrate with a heat-resistant coating film comprising the substrate and the heat-resistant coating film according to claim 8.   The base material with a heat-resistant coating film of Claim 9 whose said base material is a plant structure. The manufacturing method of the base material with a heat-resistant coating film including the following process [1] and [2].
[1] A step of coating the base material with the heat-resistant coating composition according to any one of claims 1 to 7. [2] The heat-resistant coating composition applied on the base material is dried to form a heat-resistant coating film. Forming process