KR102611925B1 - Heat-resistant coating composition, heat-resistant coating film, substrate with heat-resistant coating film and producing method thereof - Google Patents

Abstract

The object of the present invention is to provide a heat-resistant paint composition capable of forming a coating film exhibiting excellent corrosion resistance in a severe corrosive environment such as “heat insulation load” even without heat drying when forming the coating film.
The present invention relates to a heat-resistant paint composition, a heat-resistant coating film, a heat-resistant coating film attachment substrate, and a method for manufacturing the same. The heat-resistant paint composition includes a siloxane-based binder (A), mica (B), and micaceous iron oxide (C).

Description

Heat-resistant coating composition, heat-resistant coating film, heat-resistant coating film attachment substrate and manufacturing method thereof {Heat-resistant coating composition, heat-resistant coating film, substrate with heat-resistant coating film and producing method thereof}

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

In pipes such as plant structures, insulation materials are often installed around pipes (steel pipes) to suppress energy loss by preventing heat radiation to the outside air or heat absorption from the outside air. However, rainwater that penetrates between the insulation material and the steel (e.g. carbon steel, low alloy steel) pipe or moisture condensed at that location forms a water film on the surface of the steel pipe, causing corrosion under insulation (CUI). There are cases. This CUI refers to the formation of a corrosion cell on the surface of the steel pipe due to the water film, resulting in localized corrosion and erosion. Because its corrosion rate is faster than the general corrosion that occurs in the outdoor atmosphere, it has become a major problem in the maintenance and management of plant structures.

In addition, because the CUI is an insulating material (surrounded by an insulating material) in the corrosion-eroded area, moisture that once infiltrates easily accumulates and the wet state is maintained for a long period of time. Depending on the operating conditions of the plant, the piping may be exposed to high temperatures. In some cases, the progress of corrosion, which is an oxidation reaction, is accelerated. Also, since plant structures are often installed in coastal areas where sea salt particles, which can be a corrosion factor, are abundant, the sea salt particles accelerate the progress of corrosion. As a result, the corrosion and erosion are likely to become serious.

Accordingly, for the purpose of preventing the above-mentioned corrosion, etc., an anti-corrosive coating (heat-resistant coating) is installed on the outer surface of piping used in plant structures, etc.

Since piping used in plant structures, etc. is exposed to various temperature environments depending on the operating conditions of the plant, the heat-resistant temperature and heat-resistant cooling cycle conditions required for the anti-corrosion coating (heat-resistant coating) used in the piping also span a wide range. For example, in some cases, resistance to extremely high temperatures of 600℃ or higher is required. For this reason, in the past, it was necessary to closely examine the operating conditions (temperature conditions) of the plant and select and apply an anti-corrosion coating (heat-resistant coating) suitable for those conditions.

Typically, heat-resistant coating films obtained from silicone resin-based heat-resistant paints are applied to areas expected to be exposed to high temperatures of 150°C or higher.

Regarding this silicone resin-based heat-resistant paint, Patent Document 1 discloses a composition capable of forming a coating film with corrosion resistance even after exposure to a high temperature of 500°C, and Patent Document 2 discloses that the dry film thickness is 100% after two or more coats. A composition capable of forming a coating film of ~400 ㎛ is disclosed, and Patent Document 3 discloses a composition capable of forming a coating film that is curable in the range of 5 to 30°C or 40°C and has corrosion resistance and heat resistance, respectively.

Japanese Patent Publication No. 2003-213210 Japanese Patent Publication No. 11-279488 Japanese Patent Publication No. 2009-522388

As described above, a heat-resistant paint composition capable of forming a coating film with a dry film thickness of 100 to 400 ㎛, a coating composition capable of forming a coating film with corrosion resistance and heat resistance even when the coating film is formed at room temperature, and exposure to a high temperature of 500 ° C. Although heat-resistant paint compositions capable of forming a coating film with corrosion resistance even after application have been known, Patent Documents 1 to 3 state that they can form a thick coating film with a dry film thickness of 100 ㎛ or more, and can be applied at normal environmental temperatures (room temperature). Even in the case where a coating film is formed under the following conditions, a heat-resistant paint composition capable of forming a coating film with excellent anti-corrosion properties and heat resistance of 600°C or higher has not been disclosed.

When the heat-resistant coating film formed on the outer surface of piping such as a plant structure exposed to extremely high temperatures of 600°C or higher is a thick film, the heat-resistant coating film is prone to swelling or cracking due to a high temperature environment and repeated temperature changes. More specifically, when the heat-resistant coating film is exposed to high temperatures, volatilization of the residual solvent in the coating film, swelling due to gas generated by reaction and decomposition of the silicone resin component constituting the coating film, and reaction and decomposition of the silicone resin component. In some cases, cracks may occur due to an increase in the internal stress of the coating film. Since these film defects are particularly likely to occur when coated with a thick film, the film thickness of the heat-resistant film obtained from conventional silicone resin-based heat-resistant paint is usually less than 80 ㎛, and the coating specification for a thick film of 100 ㎛ or more is not. It was difficult.

However, CUI has become a major problem in maintenance management for piping in plant structures, etc., and it has been found that it is impossible to maintain long-term corrosion resistance in the case of a thin film of less than 80 ㎛ as described above in a severe corrosive environment. there was.

In addition, it was found that when using a conventional silicone resin-based heat-resistant paint, a coating film having the originally expected coating performance such as sufficient anti-corrosion resistance cannot be obtained unless it is heated and dried (baked) under certain conditions. However, since plant structures are large structures, when repair painting is performed on existing structures, heating and drying (baking) itself is often difficult. In addition, when forming a heat-resistant coating film on each member such as a steel pipe when building a plant structure, heat drying (baking) is possible, but the manufacturing cost increases due to the increase in the number of steps and energy for heating. do. Therefore, there was a demand for a paint that could form a heat-resistant film with sufficient anti-corrosion properties and other film properties required for plant structures, even when dried at room temperature (5 to 40°C).

In addition, because plant structures are subject to various temperature environments depending on operating conditions, it is necessary to select anti-corrosion coating (heat-resistant coating) and coating specifications that can withstand the environment, but this has become complicated in terms of construction management and facility maintenance. .

The present invention was made in consideration of the above problems, and provides a heat-resistant paint composition capable of forming a coating film exhibiting excellent corrosion resistance in a severe corrosive environment such as “heat insulation load” even without heat drying when forming the coating film.

In addition, a heat-resistant paint composition capable of forming a coating film capable of maintaining sufficient heat resistance, corrosion resistance, and adhesion to a substrate even when exposed to various temperatures is provided.

As a result of repeated studies on methods for solving the above-mentioned problems, the inventor discovered that the above-mentioned problems could be solved according to the following configuration, and completed the present invention.

A configuration example of the present invention is as follows.

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

<2> The heat-resistant paint composition according to <1>, wherein the mass ratio of the mica (B) and the mica-like iron oxide (C) is in the range of 90:10 to 30:70.

<3> The heat-resistant paint composition according to <1> or <2>, wherein the heat-resistant paint composition has a pigment volume concentration (PVC) of 30 to 50%.

<4> The siloxane-based binder (A) includes at least one selected from the group consisting of a silicone resin (A1) having a weight average molecular weight (Mw) of 15,000 to 300,000 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>.

<5> The heat-resistant paint composition according to <4>, wherein the siloxane binder (A) contains ethyl silicate (A3).

<6> The heat-resistant paint 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 an anti-rust pigment (E).

<8> A heat-resistant coating film formed from the heat-resistant paint composition according to any one of <1> to <7>.

A base material with a heat-resistant coating film comprising the base material <9> and the heat-resistant coating film described in <8>.

<10> The substrate with a heat-resistant coating film according to <9>, wherein the substrate is a plant structure.

<11> A method of manufacturing a substrate with a heat-resistant coating film, including the following steps [1] and [2].

[1] A process of painting the heat-resistant paint composition according to any one of <1> to <7> on a substrate.

[2] Process of forming a heat-resistant coating film by drying the heat-resistant paint composition painted on the substrate

According to the present invention, even if heat drying is not performed when forming a coating film, it exhibits excellent corrosion resistance over a long period of time in a severe corrosive environment such as "heat insulation load", and has excellent adhesion to a base material such as stainless steel, In addition, it is possible to provide a 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 extremely high temperatures exceeding 600°C.

Figure 1 is a schematic plan view of a scribed test piece used for corrosion resistance evaluation in an example.

《Heat-resistant paint composition》

The heat-resistant paint composition of one embodiment of the present invention (hereinafter simply referred to as “the present composition”) contains a siloxane-based binder (A), mica (B), and micaceous iron oxide (C).

Since this composition contains these components (A) to (C), this composition is a thick film with a dry film thickness of 100 ㎛ or more, and also has anti-corrosion and Adhesion to the substrate can be maintained, and a heat-resistant coating film with sufficient corrosion resistance can be obtained even when formed by drying at room temperature.

In addition, according to this composition, a heat-resistant coating film with good adhesion to stainless steel (e.g. SUS304, SUS316L, etc.), which is particularly applied in cases where exposure to a high temperature environment of 400°C or higher, which has a large linear expansion coefficient compared to carbon steel, is expected. can be formed.

For this reason, this composition is suitable for use on the outer surface of pipes for plant structures where operation under various temperature conditions is assumed and where insulation materials are installed, making it suitable as a paint capable of forming a heat-resistant/anti-corrosion coating film suitable for suppressing CUI. It is used.

The present composition is not particularly limited as long as it contains components (A) to (C), and depending on the purpose, the amide-based thixotropic agent (D), anti-rust pigment (E), and other components are included in the range that does not impair the effect of the present invention. It may contain pigments other than components (B), (C), and (E), pigment dispersants, anti-foaming agents, anti-sagging and anti-settling agents other than component (D), additives such as dehydrating agents, organic solvents, and curing catalysts. .

<Siloxane-based binder (A)>

The siloxane-based binder (A) is not particularly limited as long as it is a compound having a siloxane bond. This siloxane-based binder (A) is also a siloxane-based binder.

Since this composition uses a siloxane-based binder (A) as a binder, a heat-resistant coating film with particularly excellent heat resistance can be obtained.

The number of siloxane-based binders (A) contained in this composition may be one, and two or more types may be used.

Examples of the siloxane-based binder (A) include compounds that have a reactive group in the molecule via a siloxane bond, and the reactive groups react with each other to form a high molecular weight or three-dimensional crosslinked structure and harden.

Examples of the reaction include condensation reaction and addition reaction, and examples of the condensation reaction include dehydration reaction and dealcoholization reaction.

The siloxane-based binder (A) is preferably, for example, a compound represented by the formula (I) below, preferably contains the following silicone resin (A1) and/or silicone oligomer (A2), and further contains ethyl silicate (A3). ) may contain.

In particular, this composition preferably contains silicone resin (A1) as a siloxane binder (A) from the viewpoint of obtaining a heat-resistant coating film with better heat resistance and corrosion resistance, and for the purpose of adjusting the paint properties and coating film performance. Therefore, it is more preferable to use it in combination with a silicone oligomer (A2) having a lower weight average molecular weight, and it can be used in combination with ethyl silicate (A3).

The siloxane-based binder (A) may be linear or branched.

[Formula I]

(In Formula I, R ¹ each independently represents an alkyl group with 1 to 8 carbon atoms, an aryl group with 6 to 8 carbon atoms, or an alkoxy group with 1 to 8 carbon atoms, and R ² each independently represents an alkyl group with 1 to 8 carbon atoms, or an alkoxy group with 6 to 8 carbon atoms. Represents an aryl group or hydrogen atom of 8. In addition, n indicates the number of repetitions, and is selected so that the weight average molecular weight of the siloxane-based binder is in the range of 200 to 300,000.)

Examples of the alkyl group having 1 to 8 carbon atoms for R ¹ and R ² include methyl group, ethyl group, propyl group, butyl group, and pentyl group.

The aryl group having 6 to 8 carbon atoms in R ¹ and R ² may have a substituent such as an alkyl group on the aromatic ring, and examples include a phenyl group, methylphenyl group, and dimethylphenyl group.

Examples of the alkoxy group having 1 to 8 carbon atoms for R ¹ include methoxy group, ethoxy group, propoxy group, and phenoxy group.

The weight average molecular weight (hereinafter simply referred to as “Mw”) of the siloxane-based binder (A) in terms of standard polystyrene as measured by GPC (gel permeation chromatography) method is preferably 200 to 300,000, and more preferably 400. It is ~200,000.

This Mw can be specifically measured by the method described in the examples below.

The content of the siloxane-based binder (A) is preferably 20 to 45% by mass, more preferably 20 to 45% by mass, based on 100% by mass of solid content of the composition, from the viewpoint of obtaining a heat-resistant coating film with better corrosion resistance and heat resistance. 25 to 43 mass%, particularly preferably 28 to 38 mass%.

〈Silicon Resin (A1)〉

The silicone resin (A1) is not particularly limited as long as it is a compound other than ethyl silicate (A3), which will be described later, but is preferably a compound represented by the formula (I), and R ¹ in the formula (I) is a methyl group, an ethyl group, a propyl group, or Compounds with a phenyl group are more preferable, and compounds in the formula (I) in which R ² is a methyl group, ethyl group, phenyl group, or a hydrogen atom are more preferable.

The number of silicone resins (A1) contained in this composition may be one, and two or more types may be used.

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

(In formulas (a1) to (a5), “-” that is bonded to O in Si-O but not bonded to Si represents the number of bonds, and Si-O- must be Si-O-CH It does not represent _3. )

The Mw of the silicone resin (A1) is 15,000 to 300,000, preferably 18,000 to 200,000, from the viewpoint of obtaining a heat-resistant coating film with superior heat resistance and corrosion resistance.

Since the silicone resin (A1) with Mw larger than the above range has a high viscosity, when handling is taken into consideration, dilution with an organic solvent or the like may be necessary to lower the viscosity of the composition containing this silicone resin (A1). many. As a result, the solvent content in this composition increases, and there are cases where VOC (Volatile Organic Compounds) in this composition cannot be reduced.

The silicone resin (A1) may be obtained by synthesis using a conventionally known synthesis method, or may be a commercially available product. Examples of commercially available products include "SILRES REN60", "SILRES REN80" (all manufactured by Asahi Kasei Wacker Silicone Co., Ltd.), and "SILIKOPHEN P80/X" (manufactured by Evonik).

The content of the silicone resin (A1) is preferably 10 to 40% by mass, more preferably 12% by mass, based on 100% by mass of solid content of the composition, from the viewpoint of obtaining a heat-resistant coating film with superior corrosion resistance and heat resistance. ~35% by mass, particularly preferably 12-33% by mass.

<Silicone oligomer (A2)>

The silicone oligomer (A2) is not particularly limited as long as it is a compound other than ethyl silicate (A3), which will be described later, but is preferably a compound having the same structure as the structure exemplified in the silicone resin (A1) section.

The Mw of the silicone oligomer (A2) is less than 15,000, and is preferably 400 to 12,000.

There may be one type of silicone oligomer (A2) contained in this composition, and two or more types may be used.

The silicone oligomer (A2) may be obtained by synthesis using a conventionally known synthesis method, or may be a commercially available product. Examples of 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, more preferably 2%, based on 100% by mass of the solid content of the composition, from the viewpoint of obtaining a heat-resistant coating film with superior corrosion resistance and heat resistance. The amount is ~25% by mass, particularly preferably 3~10% by mass.

〈Ethyl silicate (A3)〉

The ethyl silicate (A3) is a compound composed of siloxane having an ethoxy group, and is represented by the formula (II) below.

The number of ethyl silicates (A3) contained in this composition may be one, or two or more types may be used.

[Formula II]

(In Formula II, n is 1 to 10.)

The ethyl silicate (A3) may be obtained by synthesis using a conventionally known synthesis method, or may be a commercially available product. Commercially available products include, for example, “Ethyl Silicate 40” (manufactured by Colcoat Co., Ltd.), which is an oligomer with a molecular weight distribution centered on the pentamer, and “Wackers Silicate TES 40WN” (manufactured by Asahi Kasei Wacker Silicone Co., Ltd.). I can hear it.

The content of the ethyl silicate (A3) is preferably 0 to 20% by mass based on 100% by mass of solid content of the composition from the viewpoint of obtaining a coating composition with excellent painting workability, low cost, and excellent dehydration effect during storage. , more preferably 0 to 10% by mass.

The ratio of the total content of silicone resin (A1) and silicone oligomer (A2) to the content of ethyl silicate (A3) (A1 + A2: A3) in this composition allows a heat-resistant coating film with superior heat resistance and corrosion resistance to be obtained. In terms of , it is preferably 100:0 to 90:10.

In addition, the ratio of the content of silicone resin (A1) to the total content of silicone oligomer (A2) and ethyl silicate (A3) (A1: A2 + A3) in this composition allows a heat-resistant coating film with superior heat resistance and corrosion resistance to be obtained. In terms of things like this, 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 flaky mica.

This composition is a system using a siloxane-based binder (A), and by using mica (B) and mica-like iron oxide (C) in combination, the formed coating film is 100 ㎛ even without heat drying when forming the coating film. Even if the film is thicker than above, even if it is exposed to various temperatures including high temperatures of 600°C or higher, and even in severe corrosive environments such as “heat insulation”, a heat-resistant coating film with excellent heat resistance, corrosion resistance, and adhesion to the substrate can be obtained over a long period of time. there is.

The number of mica (B) contained in this composition may be one, and two or more types may be used.

The mica (B) is classified into Muscovite, Phlogopite, etc. depending on its composition.

The mica (B) is not particularly limited, but muscovite is preferred from the viewpoint of obtaining a heat-resistant coating film with better adhesion to a substrate, especially stainless steel.

The average particle diameter (median diameter) of the mica (B) measured using a laser diffraction particle size distribution measuring device (SALD-2200, manufactured by Shimadzu Corporation) is a heat-resistant coating film with better adhesion to the substrate, especially the steel pipe. In terms of being able to obtain, it is preferably 25 to 80 ㎛, more preferably 35 to 60 ㎛.

The aspect ratio (average particle diameter/average particle thickness) of the mica (B) is preferably 10 to 150, more preferably 20 to 20, from the viewpoint of obtaining a heat-resistant coating film with better adhesion to the substrate. It's 100.

In addition, the average thickness of the particles was observed horizontally with respect to the main surface of the mica (B) using a scanning electron microscope (SEM), for example, "XL-30" (manufactured by Philips), and measured by measuring tens to hundreds of pigments. It can be calculated as the average value of particle thickness.

The mica (B) may be a commercial product, and examples of the commercial product include "Mica Powder 100 Mesh" (manufactured by Fukuoka Talc Industry Co., Ltd., average particle diameter: 41 µm).

The content of the mica (B) is preferably 15 to 60% by mass, more preferably 20 to 60% by mass, based on 100% by mass of solid content of the composition, from the viewpoint of obtaining a heat-resistant coating film with better adhesion and heat resistance. It is 40% by mass.

〈Mica-like iron oxide (C)〉

The Micacious Iron Oxide (MIO) is a pigment made of flaky (flat) or hexagonal plate-shaped iron oxide. It may be a pigment obtained by crushing and classifying natural minerals, or may be used by a conventionally known method such as hydrothermal treatment. It may be a synthetic pigment.

The number of mica-like iron oxides (C) contained in this composition may be one, and two or more types may be used.

The average particle diameter (median diameter) and average thickness of the particles of the mica-like iron oxide (C) can be measured in the same manner as the method exemplified in the mica (B) section, and the average particle diameter is heat-resistant and has superior anti-corrosion properties. From the viewpoint of being able to obtain a coating film, the range is preferably 15 to 45 ㎛, more preferably 20 to 35 ㎛.

In addition, the aspect ratio (average particle diameter/average particle thickness) of the mica-like iron oxide (C) is preferably 5 to 100, more preferably 5 to 100, from the viewpoint of obtaining a heat-resistant coating film with better adhesion to the substrate. is from 10 to 50.

The mica-like iron oxide (C) may be a commercial product. Examples of the commercial product include “MIOX 325 mesh” (manufactured by Anhui Tongling Micaceous Iron Oxide Factory, average particle diameter: 26 μm).

The content of the mica-like iron oxide (C) is preferably 10 to 40% by mass, more preferably 20 to 40% by mass, based on 100% by mass of solid content of the composition, from the viewpoint of obtaining a heat-resistant coating film with better corrosion resistance. 38% by mass, particularly preferably 27 to 35% by mass.

In this composition, from the viewpoint of obtaining a heat-resistant coating film with superior coating film physical properties after a high-temperature heat resistance test and corrosion resistance when cured at room temperature, the mass ratio of the mica (B) and the mica-like iron oxide (C) is preferably 90:10 to 30:70, more preferably 60:40 to 40:60.

<Amide thixotropic agent (D)>

This composition has excellent thixotropy by containing an amide-based thixotropic agent (D). According to the composition, a thick film with a dry film thickness of 100 ㎛ or more can be formed with a single coating, and the substrate to be coated is SUS304, SUS316L, etc. Even with the same stainless steel, a heat-resistant coating film can be obtained that has excellent adhesion to the substrate and maintains excellent adhesion even after exposure to a high temperature environment of 400°C or higher.

The number of amide-based thixotropic agents (D) contained in this composition may be one, and two or more types may be used.

The amide-based thixotropic agent (D) is not particularly limited, but examples include thixotropic agents synthesized from vegetable oil fatty acids and amines.

The amide-based thixotropic agent (D) may be synthesized and obtained by a conventionally known method, or may be a commercially available product. As commercial products, for example, "Disparon A630-20X", "Disparon 6650" (all manufactured by Kusumoto Chemicals Co., Ltd.), and "A-S-A T-250F" (manufactured by Ito Oil Chemicals Co., Ltd.) , “Plonon RCM-300TL” (manufactured by Kyoeisha Chemical Co., Ltd.).

The content of the amide-based thixotropic agent (D) is preferably 0.3 to 5% by mass with respect to 100% by mass of the solid content of the composition, from the viewpoint of exhibiting the effect of the amide-based thixotropic agent (D) more effectively. More preferably, it is 1 to 2.5 mass%.

〈Rust-prevention pigment (E)〉

By containing the rust preventive pigment (E), this composition can obtain a heat-resistant coating film with excellent corrosion resistance even when cured and dried at room temperature.

The number of rust preventive pigments (E) contained in this composition may be one, and two or more types may be used.

The rust preventive pigment (E) is not particularly limited and includes conventionally known rust preventive pigments. Preferably, they are lead- and chromium-free rust-prevention pigments, more preferably phosphate-based rust-prevention pigments, and particularly preferably zinc-phosphate-based rust-prevention pigments and aluminum phosphate-based rust-prevention pigments.

The rust preventive pigment (E) may be a commercial product, and examples of commercial products include "LF Bowsei ZP-N" and "LF Bowsei PM-303W" (both manufactured by Kikuchi Color Co., Ltd.).

The content of the rust preventive pigment (E) is preferably 1 to 10% by mass, more preferably 100% by mass, based on 100% by mass of the solid content of the composition, from the viewpoint of demonstrating the effect of the rust preventive pigment (E) described above. It is 3 to 8 mass%.

〈Other ingredients〉

This composition contains pigments (coloring pigments and extenders) other than mica (B), mica-like iron oxide (C), and rust preventive pigment (E), pigment dispersants, antifoaming agents, and amides, as necessary, as long as they do not impair the effect of the present invention. Other than the thixotropic agent (D), it may contain additives such as anti-sagging and anti-settling agents and dehydrating agents, organic solvents, and curing catalysts.

The number of these other components may be one, or two or more types may be used.

(coloring pigment)

The coloring pigment is not particularly limited, but is preferably a coloring pigment with heat resistance, and examples include Pigment Black 28 (Copper chromite black spinel), aluminum flake, stainless steel flake, titanium white, carbon black, and Bengala.

Commercially available products of the coloring pigment include, for example, “CFP-4010BK” (MnO _2- Fe ₂ O _3- CuO-Co ₃ O ₄ , manufactured by Okuno Chemical Industries, Ltd.), which is a chrome-free black inorganic pigment, and aluminum paste. Examples include “Al-Paste 0100M-C70” (manufactured by Toyo Aluminum Co., Ltd.).

〈Constitutional pigment〉

The extender pigment is not particularly limited, but is preferably a extender pigment with heat resistance, and examples include talc, silica, potassium feldspar, barium sulfate, zinc oxide, calcium carbonate, kaolin, and aluminum oxide.

<Pigment dispersant>

The pigment dispersant is not particularly limited, but is preferably a dispersant that can uniformly disperse the pigment in the present composition and prepare a stable dispersion.

The pigment dispersant may be a commercial product, and examples of the commercial product include "Disperbyk-180" and "Disperbyk-2022" (both manufactured by Big Chemie Japan Co., Ltd.).

〈Defoamer〉

The antifoaming agent is not particularly limited, but is preferably a material capable of suppressing the generation of air bubbles during production or coating of the present composition, or a material capable of breaking air bubbles generated in the present composition.

The above-mentioned antifoaming agent may be a commercial product, and examples of commercial products include "BYK-320", "BYK-066N", and "BYK-1790" (all manufactured by Big Chemi Japan Co., Ltd.).

<Anti-sagging/anti-settling agent>

The anti-sagging and anti-settling agent is not particularly limited, but is a material that can suppress pigment sedimentation of the present composition and improve its storage stability, or a material that can improve the anti-sagging property of the coating composition during or after painting. desirable.

Examples of anti-sagging and anti-settling agents include organic thixotropic agents such as hydrogenated castor oil-based thixotropic agents and oxidized polyethylene-based thixotropic agents, side deposit minerals such as bentonite, and inorganic thixotropic agents such as synthetic fine powder silica. Among these, Side deposit minerals such as oxidized polyethylene-based thixotropic agents, synthetic finely divided silica, and bentonite are preferred.

The anti-sagging and anti-settling agent may be a commercial product. Examples of the commercial product include "Bentone38" (manufactured by Elementis Specialties Inc.), which is an organic modified bentonite-based viscosity regulator (hectorite/quaternary amine), and a silicon dioxide-based agent. Examples include "Aerosil R972" (manufactured by Nippon Aerosil Co., Ltd.), which is a regenerative agent, and "A-S-A D-120" (manufactured by Ito Oil Chemicals Co., Ltd.), which is a polyethylene oxide-based thixotropic agent.

The content of the anti-sagging and anti-settling agent is preferably 0.1 to 10% by mass based on 100% by mass of solid content of the composition.

〈Dehydrating agent〉

The dehydrating agent is not particularly limited as long as it has a dehydrating effect, but it is preferable that it is a material that can suppress a decrease in storage stability of the present composition due to excessive moisture.

Examples of such dehydrating agents include anhydrous gypsum and vinyltrimethoxysilane.

〈Organic solvent〉

When this composition is applied to a plant structure at a high temperature during plant operation, especially a substrate such as the outer surface of a pipe, the organic solvent is likely to volatilize due to heat on the surface of the substrate, making it difficult to form a good coating film. For this reason, it is preferable that the organic solvent contains an organic solvent with 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 organic solvents include xylene, toluene, and n-butyl alcohol.

〈Curing Catalyst〉

The curing catalyst is not particularly limited, but is preferably a material that has the effect of promoting the crosslinking reaction of the siloxane binder (A), for example, aminosilane, titanium alkoxide, titanium chelate, metal soap such as aluminum and zinc. , phosphoric acid, and phosphoric acid ester. Among these, metal soaps such as aluminum and zinc are preferable from the viewpoint of the tendency to easily form the composition into a one-component form.

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

〈Heat-resistant paint composition〉

The pigment volume concentration (PVC: Pigment Volume Concentration) of this composition is preferably 30 to 30 in terms of obtaining a heat-resistant coating film with superior corrosion resistance and superior adhesion to the substrate after heat drying. 50%, more preferably 35 to 45%.

If the PVC is below the above range, the corrosion resistance of the heat-resistant coating film formed tends to decrease, and the adhesion of the coating film to the substrate after heat drying also tends to decrease. Additionally, when the PVC content exceeds the above range, the corrosion resistance of the heat-resistant coating film formed tends to decrease.

The PVC refers to the total volume concentration of the pigment relative to the volume of solid content (non-volatile content) in this composition. PVC can be specifically calculated using the formula below.

PVC [%] = Total volume of all pigments in this composition × 100 / Volume of solid content in this composition

In addition, in this specification, the solid content of the present composition means the heating residue obtained according to JIS K 5601-1-2 (heating temperature: 125°C, heating time: 60 minutes). In addition, the solid content of this composition can also be calculated as the amount excluding the solvent in the raw materials used and the organic solvent.

The volume of the solid content in the composition can be calculated from the mass and true density of the solid content in 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.

This composition is preferably a one-component paint composition from the viewpoint of providing excellent painting workability, etc.; however, it is also possible to use it as a two-component paint composition in which the curing catalyst is mixed and stirred immediately before the start of painting work.

《Heat-resistant coating film and heat-resistant coating film attachment base》

The heat-resistant coating film (hereinafter also referred to as “this heat-resistant coating film”) of one embodiment of the present invention is formed of the composition described above, and the base material with the heat-resistant coating film of one embodiment of the present invention is a laminate comprising the present heat-resistant coating film and the base material. It's a chaser.

The substrate is not particularly limited and includes, for example, a metal substrate made of steel (iron, steel, ferroalloy, carbon steel, alloy steel, etc.), a non-ferrous metal (stainless steel, aluminum, etc.), and a metal substrate whose surface is coated with shop primer, etc. I can hear it. In addition, the base material includes plant structures, land structures, marine structures, ships, etc., but from the viewpoint of demonstrating the effect of the present invention more, plant structures are preferable, and among plant structures, plant piping is more preferable. As the above-mentioned base material, carbon steel used in plant piping, ships, and marine structures, or stainless steel such as SUS304 and SUS316L, which are suitably used in areas requiring cold resistance and heat resistance, are more preferable.

The film thickness of this heat-resistant coating film is not particularly limited as long as it is thick enough to protect the base material from corrosion, but is preferably 100 to 400 ㎛, more preferably 150 to 280 ㎛.

Because this composition is used, even if a coating film of this thickness is formed on a substrate, swelling (blisters) or cracks are unlikely to occur in the coating film, especially when exposed to high temperatures of 400°C or higher or rapid temperature changes. Since it is difficult for cracks or cracks to occur, the substrate can be protected from corrosion over a long period of time.

In addition, considering corrosion resistance, a thicker film is desirable, but in the case of an excessively thick film, residual solvents contained in the film are volatilized by heating, causing swelling in the film, or the siloxane binder (A) or its There is a tendency for the internal stress of the coating film to increase due to structural changes due to the reaction or decomposition of the binder-derived components, and the accompanying cracks and peeling tend to occur.

This heat-resistant coating film is formed from the above-described composition, and can be specifically manufactured by passing through processes including the following processes [1] and [2].

[1] Process of coating this composition on a substrate

[2] Process of forming a heat-resistant coating film by drying the heat-resistant paint composition painted on the substrate

Additionally, by including the following process [3], this method can form a heat-resistant coating film with better corrosion resistance and heat resistance.

[3] A process of heating the coating film obtained in the above process [2] at 150 to 250 ° C.

〈Process [1]〉

The method of coating the composition on the substrate is not particularly limited, and conventionally known methods can be used without limitation, and commonly used airless spray coating, air spray coating, brush coating, roller coating, etc. are preferred. Spray coating is preferred in that it has excellent workability and productivity, can be easily applied to a large-area substrate, and can further demonstrate the effects of the present invention.

Additionally, when the present composition is a two-component composition, spray painting, etc. may be performed by mixing the main component and a curing accelerator component (component containing the above-mentioned curing catalyst) immediately before painting.

The conditions of the spray painting can be adjusted appropriately depending on the thickness of the heat-resistant coating film to be formed. For example, in the case of airless spraying, primary (air) pressure: approximately 0.4 ~ 0.8 MPa, secondary (paint) pressure: 10 ~ Just set the painting conditions to about 26 MPa, gun moving speed: 50 to 120 cm/sec.

The viscosity of the composition used at this time is adjusted with a thinner, and when measured with a type B viscometer (“TVB-10M, manufactured by Toki Sangyo Co., Ltd.), the viscosity is preferably about 1.8 to 2.5 Pa·s at 23°C. . The thinner is preferably an organic solvent capable of dissolving or dispersing the components in the composition, for example, aromatic hydrocarbon solvents such as toluene and xylene, mineral spirits, aliphatic hydrocarbon solvents such as cyclohexane, n-butanol, isopropanol, etc. alcohol-based solvents. The number of thinners used may be one, or two or more types may be used.

When applying this composition to plant pipes, etc., it is possible to apply it to pipes at relatively high temperatures without stopping the operation of the plant. However, in this case, the sprayed paint solidifies before forming a uniform and smooth film on the surface of the base material. It becomes easier to be painted as dust. For the purpose of suppressing this, a high boiling point solvent can be used as the thinner.

When coating this composition on a substrate, the surface of the substrate is treated as necessary to remove rust, oil, moisture, dust, salt, etc. on the substrate and to improve the adhesion of the resulting heat-resistant coating film to the substrate. (For example, blasting (ISO8501-1 Sa2 1/2), treatment to remove oil and dust by degreasing), etc. are desirable. Additionally, the above substrate may be coated with shop primer or the like for the purpose of primary rust prevention.

〈Process [2]〉

This composition can be dried and cured at room temperature, and even by drying and curing at room temperature, a heat-resistant coating film with excellent heat resistance and corrosion resistance can be obtained. Additionally, depending on the purpose, it may be dried under heating to shorten the drying time.

The drying conditions are not particularly limited and can be set appropriately depending on the composition, substrate, coating location, etc.; the drying temperature is preferably 5 to 40°C, more preferably 10 to 30°C, and the drying time is preferably 5 to 40°C. 18 hours to 14 days, more preferably 24 hours to 7 days.

〈Process [3]〉

By performing the above step [3], a heat-resistant coating film that is more physically and chemically resistant can be formed. In other words, it becomes possible to form a heat-resistant coating film with higher coating hardness or more excellent corrosion resistance.

The heating conditions in the above step [3] are not particularly limited, but the heating temperature is preferably 150 to 250°C, and the heating time is preferably 10 minutes to 3 hours, more preferably 30 minutes to 1 hour. .

As a method of forming a heat-resistant coating film of the above film thickness, a coating film of the desired film thickness may be formed with one coating, or a coating film of the desired film thickness may be formed with two or more coatings (two or more coats). From the viewpoint of film thickness management and considering the residual solvent in the coating film, it is preferable to form a coating film of the desired film thickness by applying two or more coats.

In addition, two coats of paint (two coats) mean that after performing processes [1] and [2] and, if necessary, process [3], on the obtained coating film, processes [1] and [2], if necessary, are applied. This refers to the method of performing [3], and painting more than 3 times refers to the method of repeating a series of additional processes.

When forming a coating film by applying two or more coats, for example, it is preferable that the color of the paint/coat film applied the first time is different from the color of the paint/coat film applied next time. This is a measure to facilitate the judgment of cases where paint is forgotten or not painted, or film thickness is insufficient during painting work. Additionally, a top coat may be applied to finish the final outer surface in a designated color.

Example

The present invention is further explained below by way of examples, but the present invention is not limited thereto.

<Weight average molecular weight of siloxane binder (A)>

The weight average molecular weight (Mw) of the siloxane-based binder (A) was measured by GPC method under the following conditions.

·Device: “Alliance 2695” (manufactured by Waters)

Column: Connect 1 “TSKgel SuperH4000” and 2 “TSKgel SuperH2000” (all manufactured by Tosoh Co., Ltd., inner diameter 6 mm × length 15 cm)

·Eluent: Tetrahydrofuran 99% (Stabilized with BHT)

·Flow rate: 0.6 mL/min

・Detector: “RI-104” (manufactured by Shodex)

·Column thermostat temperature: 40℃

·Standard material: standard polystyrene

·Sample preparation method: Measure out the sample into a sample tube, add tetrahydrofuran and dilute about 100 times.

[Example 1]

Add 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 into a container, and additionally add 30.3 parts by mass of SILRES REN80 and 1 mass of Disparon 6650. 4 mass parts of LF Bowsey ZP-N were added and stirred with a high-speed disper to uniformly disperse.

36.9 parts by mass of 100 mesh mica powder was added to the obtained mixture and stirred, and the temperature of the mixture was raised to 58°C by the heat generated by the stirring.

Also, add 8.3 parts by mass of MIOX 325 mesh and stir to disperse evenly, cool to 30°C or lower, add 1.5 parts by mass of D-15, stir to disperse evenly, and filter through a 60 mesh nylon mesh to obtain the paint composition. It 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 numbers written in the raw material column of Tables 2 to 5 represent parts by mass.

In addition, details of each raw material listed in Tables 2 to 5 are as shown in Table 1.

In addition, the solid content (mass %) of each component in Table 1 is the manufacturer's catalog value.

〈Evaluation of coating film properties〉

(1)Unheated test

The viscosity of the coating composition obtained in the examples and comparative examples was adjusted using xylene so that the viscosity at 23°C measured using the above-mentioned type B viscometer was 2.0 Pa·s.

The paint composition after viscosity adjustment was applied to a SS400 sandblasted (equivalent to ISO8501-1 Sa2 1/2) steel plate using a film applicator with a gap of 700 μm so that the dry film thickness was 250 μm.

Thereafter, the coating composition applied on the steel plate was dried at 23°C for 7 days to produce a test piece (substrate with a coating film).

The obtained test pieces were evaluated according to the evaluation criteria below.

5: Good appearance of the coating film with no cracks or peeling. Good curing and drying properties.

4: The appearance of the coating film is good with no cracks or peeling, but adhesion remains on the surface of the coating film.

3: When using a magnifying glass, cracks, etc. can be seen on the surface of the coating film.

2: Even without using a magnifying glass, cracks were confirmed in some parts of the coating film.

1: The occurrence of cracks or peeling was confirmed throughout the entire coating film.

(2)HRT(Heat Resistant Test)

The test piece obtained in the same manner as the (1) unheated test above was placed in a muffle furnace and heated at 650°C for 4 hours, and then left to cool. The test piece obtained was evaluated according to the same evaluation criteria as the (1) unheated test above. did.

(3) Thermal shock test

The test piece obtained in the same manner as the unheated test (1) above was placed in an oven and heated at 400°C for 8 hours, then taken out of the oven and immediately immersed in ice water for 10 seconds to rapidly cool it. Afterwards, the test piece was taken out of the ice water, the water droplets attached to the test piece were removed with a paper rag, and the test piece was left at room temperature overnight. After performing this heating and quenching an additional two times (heating and quenching a total of 3 times), the obtained test piece was evaluated according to the same evaluation criteria as the unheated test (1) above.

(4)HRT (SUS-based)

A test piece was produced in the same manner as the unheated test (1) above, except that a SUS304 sand sweep (equivalent to ISO8501-1 Sa1) plate was used instead of the steel plate.

Except that the obtained test piece was used, the test piece obtained by heating and cooling was carried out in the same manner as in (2) HRT above, and was evaluated according to the evaluation criteria below.

5: Good appearance of the coating film with no cracks or peeling.

4: Peeling was confirmed in a very small portion (less than 5% of the area) of the coating film.

3: Peeling was confirmed in a portion of the coating film (5% to 20% in area).

2: Peeling was confirmed in the coating film equivalent to an area of 20% to 50% of the entire surface of the coating film.

1: The entire surface of the coating film has peeled off or cracks have been confirmed on the entire surface of the coating film.

〈Corrosion resistance evaluation〉

The corrosion resistance evaluation is performed by placing a scratch (scribe) deep enough to expose a portion of the steel plate at the location shown in Figure 1 of each test piece after performing the above coating film physical property evaluation (1) to (3), and additionally applying the paint composition. In order to eliminate the influence of unpainted areas, test specimens whose back and edges were painted with epoxy-based anti-corrosion paint were used, and a salt spray test (35°C) was performed on each test specimen for 3 weeks in accordance with JIS Z 2371, as shown below. It was evaluated according to the evaluation criteria.

5: Rusting (rusting) is not confirmed in the evaluation target area.

4: Slight rusting (less than 1% in area) was confirmed in the area subject to evaluation.

3: Rusting was confirmed in a portion of the area subject to evaluation (more than 1% but less than 5% by area).

2: Rusting was confirmed in a portion of the area subject to evaluation (5% or more in area).

1: Rusting accompanying peeling or lifting of the coating film was confirmed.

Here, the “evaluation target area” refers to the area excluding the area of 1 cm from the end of the test piece in consideration of the influence of the epoxy-based anti-corrosion paint.

In addition, the “unheated test (general part)” in Tables 3, 4, and 5 below refers to a test in which the above-mentioned corrosion test was performed using the test piece after the (1) unheated test in the evaluation of the coating film properties, and the evaluation target part This is a test that evaluated the normal portion shown in FIG. 1 (a portion excluding an area of 1 cm from the end of the test specimen and also excluding an area of 1 cm from the scribe).

The “unheated test (scribe section)” in Tables 2, 3, 4, and 5 below refers to a test in which the above-mentioned corrosion test was performed using a test piece after performing (1) the unheated test in the evaluation of the above-mentioned coating film properties. This is a test that evaluated the scribe portion shown in FIG. 1 among the target portions (a portion excluding an area of 1 cm from the end of the test piece, and a portion within a range of 1 cm from the scribe).

“HRT (normal section)” and “HRT (scribe section)” in Table 5 below are tests in which the above-mentioned corrosion test was performed using a test piece after performing (2) HRT (Heat Resistant Test) in the evaluation of the above-mentioned coating film properties. . “HRT (normal part)” is a test that evaluates the general part shown in FIG. 1 among the parts to be evaluated, and “HRT (scribed part)” is a test that evaluates the scribe part shown in FIG. 1 among the parts to be evaluated.

In addition, in the corrosion resistance items in Tables 3 to 5, evaluations without “(normal section)” or “(scribed section)” are the results of evaluation using both the normal section and the scribe section shown in FIG. 1 as evaluation target sections.

Claims (11)

Contains a siloxane-based binder (A), mica (B), mica-like iron oxide (C), and an amide-based thixotropic agent (D),
The siloxane-based binder (A) contains a silicone resin (A1) having a weight average molecular weight of 15,000 or more and a silicone oligomer (A2) having a weight average molecular weight of less than 15,000.
Heat-resistant paint composition. According to paragraph 1,
A heat-resistant paint composition wherein the mass ratio of the mica (B) and the mica-like iron oxide (C) is in the range of 90:10 to 30:70. According to paragraph 1,
A heat-resistant paint composition having a pigment volume concentration (PVC) of 30 to 50%. According to paragraph 1,
A heat-resistant paint composition, wherein the silicone resin (A1) is a silicone resin having a weight average molecular weight (Mw) of 15,000 or more and 300,000 or less. According to paragraph 4,
A heat-resistant paint composition wherein the siloxane-based binder (A) includes ethyl silicate (A3). delete According to paragraph 1,
A heat-resistant paint composition further comprising a rust-prevention pigment (E). A heat-resistant coating film formed from the heat-resistant paint composition according to any one of claims 1 to 5 and 7. A substrate with a heat-resistant coating film comprising a substrate and the heat-resistant coating film described in claim 8. According to clause 9,
A substrate with a heat-resistant coating film, wherein the substrate is a plant structure. A method of manufacturing a heat-resistant coating film-attached substrate including the following steps [1] and [2].
[1] Process of painting the heat-resistant paint composition according to any one of paragraphs 1 to 5 and 7 on a substrate.
[2] Process of forming a heat-resistant coating film by drying the heat-resistant paint composition painted on the substrate