JP7089938B2 - Heat-resistant paint composition, heat-resistant coating film, base material with heat-resistant coating film and its manufacturing method - Google Patents

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 the pipes of plant structures, etc., heat insulating materials are often installed around the pipes (steel pipes) in order to prevent heat dissipation to the outside air and heat absorption from the outside air and to suppress energy loss. However, rainwater that has entered the gap between the heat insulating material and the steel (eg, carbon steel, low alloy steel) pipe and the water that has aggregated at that location form a water film on the surface of the steel pipe, causing corrosion under the heat insulating material (CUI). : Corrosion Under Insulation) may occur. The CUI means that local corrosion erosion occurs by forming a corrosive battery on the surface of a steel pipe due to the water film. Its corrosion rate is faster than the total corrosion that occurs in the outdoor atmosphere, which poses a major problem in the maintenance of plant structures.

Further, in the CUI, since the corroded erosion site is under the heat insulating material (surrounded by the heat insulating material), the moisture once invaded easily stays and the moist state is maintained for a long period of time, depending on the operating conditions of the plant. Since 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, which can be a corrosion factor. Therefore, the corrosion erosion is likely to become serious because the sea salt particles promote the progress of corrosion.

Therefore, for the purpose of preventing the corrosion and the like, the piping used for the plant structure and the like is provided with an anticorrosion coating film (heat resistant coating film) on the outer surface thereof.
Piping used for plant structures, etc. is exposed to various temperature environments depending on the operating conditions of the plant. Therefore, the heat resistant temperature and heat resistant cooling cycle required for the anticorrosion coating film (heat resistant coating film) used for the piping. The conditions are also wide-ranging, and for example, resistance to an ultra-high temperature of 600 ° C. or higher may be required. Therefore, conventionally, it has been necessary to carefully examine the operating conditions (temperature conditions) of the plant and select and apply an anticorrosion coating film (heat-resistant coating film) suitable for the conditions.

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

Japanese Unexamined Patent Publication No. 2003-2132010 Japanese Unexamined Patent Publication No. 11-279488 Special Table 2009-522388 Gazette

As described above, a heat-resistant coating film 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 corrosion resistance even after being exposed to a high temperature of 500 ° C. have been known, they are dried in any of Patent Documents 1 to 3. A thick coating film having a film thickness of 100 μm or more can be formed, and even when the coating film is formed at a normal environmental temperature (normal temperature), a coating film having excellent corrosion resistance is formed. 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 piping of a plant structure or the like exposed to an ultra-high temperature of 600 ° C. or higher is a thick film, the heat-resistant coating film is subjected to a high temperature environment and repeated temperature changes. Bulging and cracking are likely to occur. More specifically, when the heat-resistant coating film is exposed to a high temperature, the residual solvent in the coating film volatilizes, and the silicone resin component constituting the coating film swells due to gas generated by the reaction / decomposition. In addition, cracks may occur due to an increase in the internal stress of the coating film due to the reaction / decomposition of the silicone resin component. Since these coating film defects are particularly likely to occur when a thick film is coated, the film thickness of the heat-resistant coating film obtained from the conventional silicone resin-based heat-resistant paint is usually less than 80 μm, and is 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, etc., and it is not possible to maintain long-term corrosion resistance with a thin film of less than 80 μm as described above against the severe corrosive environment. I found that I couldn't.

Further, it was found that when a conventional silicone resin-based heat-resistant paint is used, a coating film having sufficient coating film performance such as corrosion resistance, which is originally expected, cannot be obtained unless it is heat-dried (baked) under certain conditions. rice field. However, since the plant structure is a large structure, it is often difficult to heat-dry (bake) the existing structure for repair painting. Further, when a heat-resistant coating film is formed on each member such as a steel pipe at the time of construction of a plant structure, it can be heat-dried (baked), but the number of steps is increased and energy for heating is increased. The manufacturing cost increases due to such factors. Therefore, there has been a demand for a paint capable of forming a heat-resistant coating film having sufficient coating film performance such as corrosion resistance required for a plant structure even if the coating film is formed by drying at room temperature (5 to 40 ° C.).
Furthermore, since the plant structure has various temperature environments depending on the operating conditions, it is necessary to select an anticorrosion coating film (heat resistant coating film) and coating specifications that can withstand the environment. The management is complicated.

The present invention has been made in view of the above problems, and a coating film exhibiting excellent corrosion resistance in a severe corrosive environment such as "under a heat insulating material" without heat-drying when forming the coating film. Provided is a heat resistant coating composition capable of forming the above.
Further, the present invention provides a heat-resistant coating 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.

As a result of diligent studies on a method for solving the above-mentioned problem, the inventor has found that the above-mentioned problem can be solved by the following configuration, and has completed the present invention.
The 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 the mass ratio of the mica (B) to the mica-like iron oxide (C) is in the 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) is composed 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 coating composition according to any one of <1> to <3>, which comprises at least one selected from the group.
<5> The heat-resistant coating composition according to <4>, wherein the siloxane binder (A) contains ethyl silicate (A3).

<6> The heat-resistant coating composition according to any one of <1> to <5>, further comprising an amide-based rocking agent (D).
<7> The heat-resistant coating 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 base material with a heat-resistant coating film containing the base material and the heat-resistant coating film according to <8>.
<10> The base material with a heat-resistant coating film according to <9>, wherein the base material is a plant structure.

<11> A method for producing a base material with a heat-resistant coating film, which comprises the following steps [1] and [2].
[1] Step of applying the heat-resistant coating composition according to any one of <1> to <7> on the base material [2] The heat-resistant coating composition coated on the base material is dried to form a heat-resistant coating film. Forming process

According to the present invention, even if heat-drying is not performed when forming a coating film, excellent corrosion resistance is exhibited for a long period of time in a severe corrosive environment such as "under a heat insulating material", and a base material such as stainless steel is used. 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 under a wide range of temperatures including ultra-high temperatures exceeding 600 ° C. Can provide things.

FIG. 1 is a schematic plan view of a test piece containing a scribe used for evaluation of corrosion resistance in Examples.

≪Heat-resistant paint composition≫
The heat-resistant coating composition according to one 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, it is a thick film having a dry film thickness of 100 μm or more and is exposed to a high temperature environment exceeding 600 ° C. Even after that, it is possible to maintain the corrosion resistance and the adhesiveness to the substrate, and it is possible to obtain a heat-resistant coating film having sufficient corrosion resistance even if it is formed by drying at room temperature.
Further, according to the present composition, stainless steel (eg, SUS304, which is applied when it is expected to be exposed to a high temperature environment of 400 ° C. or higher, which has a larger coefficient of linear expansion than carbon steel, is particularly applicable. It is possible to form a heat-resistant coating film having good adhesion to SUS316L or the like).
For this reason, this composition is suitably used for the outer surface of pipes for plant structures, which is expected to operate under various temperature conditions and in which a heat insulating material is installed, and is heat resistant / suitable for suppressing CUI. It is suitably used as a paint capable of forming an anticorrosion coating film.

The present composition is not particularly limited as long as it contains the components (A) to (C), and if desired, the amide-based rocking agent (D) and the rust preventive pigment (E) are used as long as the effects of the present invention are not impaired. As other components, pigments other than the components (B), (C) and (E), pigment dispersants, defoamers, anti-sagging / sedimentation agents other than the component (D), additives such as dehydrating agents, etc. It may contain an organic solvent, a curing catalyst and the like.

<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.
Since the siloxane-based binder (A) is used as the binder in this composition, a heat-resistant coating film having particularly excellent heat resistance can be obtained.
The siloxane-based binder (A) contained in the present composition may be one kind or two or more kinds.

The siloxane-based binder (A) has, for example, 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. Examples include compounds that cure.
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 present composition preferably contains a silicone resin (A1) as the siloxane binder (A) from the viewpoint that a heat-resistant coating film having excellent heat resistance and corrosion resistance can be obtained, and the coating properties and coating are preferably contained. For the purpose of adjusting the film performance, it is more preferable to use it in combination with a silicone oligomer (A2) having a lower weight average molecular weight, and further, ethyl silicate (A3) can be used in combination.
The siloxane-based binder (A) may be linear or branched.

（式（Ｉ）中、Ｒ¹はそれぞれ独立に、炭素数１～８のアルキル基、炭素数６～８のアリール基または炭素数１～８のアルコキシ基を示し、Ｒ²はそれぞれ独立に、炭素数１～８のアルキル基、炭素数６～８のアリール基または水素原子を示す。また、ｎは繰り返し数を示し、シロキサン系バインダーの重量平均分子量が２００～３００，０００の範囲となるように選択される。）

(In the formula (I), 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 R ² independently represents each other. An alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 8 carbon atoms or a hydrogen atom is indicated. In addition, n indicates the number of repetitions so that the weight average molecular weight of the siloxane-based binder is in the range of 200 to 300,000. Is 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. Be 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 to 200,000.
Specifically, the Mw can be measured by the method described in the following Examples.

The content of the siloxane-based binder (A) is preferably 20 to 45% 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 having excellent corrosion resistance and heat resistance can be obtained. %, More preferably 25 to 43% by mass, and 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 the 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.
The silicone resin (A1) contained in the present composition may be one kind or two or more kinds.

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

（式（ａ１）～（ａ５）中、Ｓｉ－Ｏ－における、Ｏに結合し、Ｓｉに結合していない「－」は、結合手を示し、Ｓｉ－Ｏ－は、必ずしもＳｉ－Ｏ－ＣＨ₃を示すわけではない。）

(In the formulas (a1) to (a5), "-" in Si—O— that is bound to O and not bound to Si indicates a bond, and Si—O— is necessarily Si—O—CH. It does not indicate _3. )

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 or more, from the viewpoint that a heat-resistant coating film having excellent heat resistance and corrosion resistance can be obtained. It is as follows.
Since the silicone resin (A1) having Mw larger than the above range has a high viscosity, it is diluted with an organic solvent or the like in order to reduce the viscosity of the present composition containing such a silicone resin (A1) in consideration of handleability. Is often required. As a result, the solvent content in the composition increases, and VOCs (Volatile Organic Compounds) in the composition may not be reduced.

The silicone resin (A1) may be obtained by synthesizing it by a conventionally known synthetic method, or may be a commercially available product. Examples of the commercially available product 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 with respect to 100% by mass of the solid content of the present composition from the viewpoint that a heat-resistant coating film having excellent corrosion resistance and heat resistance can be obtained. , More preferably 12 to 35% by mass, and particularly preferably 12 to 33% by 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 it is preferably a compound having the same structure as that described in the column of the silicone resin (A1). ..
The Mw of the silicone oligomer (A2) is less than 15,000, preferably 400 to 12,000.
The silicone oligomer (A2) contained in the present composition may be one kind or two or more kinds.

The silicone oligomer (A2) may be obtained by synthesizing it by a conventionally known synthetic method, or may be a commercially available product. Examples of the commercially available product 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 having excellent corrosion resistance and heat resistance can be obtained. , More preferably 2 to 25% by mass, and particularly preferably 3 to 10% by mass.

<Ethyl silicate (A3)>
The ethyl silicate (A3) is a compound composed of a siloxane having an ethoxy group and is represented by the following formula (II).
The ethyl silicate (A3) contained in the present composition may be one kind or two or more kinds.

（式（ＩＩ）中、ｎは１～１０である。）

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

The ethyl silicate (A3) may be obtained by synthesizing it by a conventionally known synthetic method, or may be a commercially available product. Examples of the commercially available products include "Ethyl Silicate 40" (manufactured by Corcote 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. Can be mentioned.

The content of the ethyl silicate (A3) is based on 100% by mass of the solid content of the present composition from the viewpoints of obtaining a coating composition excellent in coating workability, cost reduction and dehydration effect during storage. It 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) to the content of the ethyl silicate (A3) in the present composition is a heat-resistant coating film having excellent heat resistance and corrosion resistance. It is preferably 100: 0 to 90:10 from the viewpoint that the above can be obtained.

Further, the ratio (A1: A2 + A3) of the content of the silicone resin (A1) to the total content of the silicone oligomer (A2) and the ethyl silicate (A3) in the present composition is heat resistance excellent in heat resistance and corrosion resistance. It is preferably 90:10 to 30:70, and more preferably 90:10 to 40:60 from the viewpoint that a coating film can be obtained.

<Mica (B)>
The mica (B) is not particularly limited as long as it is a scaly (flat) mica.
This composition does not require heat drying when forming a coating film for the first time by using mica (B) and mica-like iron oxide (C) in combination in a system using a siloxane-based binder (A). However, even if the formed coating film is a thick film of 100 μm or more, exposed to various temperatures including high temperature of 600 ° C or more, and even in a severe corrosive environment such as “under heat insulating material”, for a long period of time. A heat-resistant coating film having excellent heat resistance, corrosion resistance, and adhesion to a substrate can be obtained.
The mica (B) contained in the present composition may be one kind or two or more kinds.

The mica (B) is classified into white mica (Muscovite), phlogopite, and the like according to its composition.
The mica (B) is not particularly limited, but white mica is preferable from the viewpoint that a heat-resistant coating film having better adhesion to a base material, particularly stainless steel can be obtained.

The average particle size (median diameter) of the mica (B) measured using a laser diffraction type particle size distribution measuring device (SALD-2200, manufactured by Shimadzu Corporation) depends on the adhesion to the substrate, especially the steel pipe. It is preferably 25 to 80 μm, more preferably 35 to 60 μm, from the viewpoint that an excellent heat-resistant coating film can be obtained.

The aspect ratio (average particle size / average thickness of particles) of the mica (B) is preferably 10 to 150, more preferably, from the viewpoint that a heat-resistant coating film having better adhesion to the substrate can be obtained. Is 20 to 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 Phillips), and the average thickness was several tens. It can be calculated as an average value of the thicknesses of up to 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 Industry 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 having better adhesiveness and heat resistance can be obtained. More preferably, it is 20 to 40% by mass.

<Mica-like iron oxide (C)>
The micaus iron oxide (MIO) is a pigment composed of scaly (flat) and hexagonal plate-shaped 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 present composition may be one kind or two or more kinds.

The mica-like iron oxide (C) can measure the average particle diameter (median diameter) and the average thickness of the particles by the same method as the method mentioned in the column of the mica (B), and the average particle diameter thereof. Is preferably 15 to 45 μm, more preferably 20 to 35 μm, from the viewpoint that a heat-resistant coating film having better corrosion resistance can be obtained.
Further, the aspect ratio (average particle size / average thickness of particles) of the mica-like iron oxide (C) is preferably 5 to 100 from the viewpoint that a heat-resistant coating film having better adhesion to a substrate can be obtained. , More preferably 10 to 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 Microceous Iron Oxide Factory, average particle diameter: 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 having excellent corrosion resistance can be obtained. It is more preferably 20 to 38% by mass, and particularly preferably 27 to 35% by mass.

In this composition, the mica (B) and the mica-like iron oxide (C) are used from the viewpoint that a heat-resistant coating film having excellent physical properties after a high-temperature heat resistance test and corrosion resistance at room temperature curing can be obtained. The mass ratio of is preferably 90:10 to 30:70, more preferably 60:40 to 40:60.

<Amid-based rocking agent (D)>
This composition is excellent in rocking denaturation by containing an amide-based rocking agent (D), and according to the composition, a thick film having a dry film thickness of 100 μm or more can be formed by one coating, and coating is performed. Even if the target base material is stainless steel such as SUS304, SUS316L, etc., it has excellent adhesion to the base material and has excellent adhesion even after being exposed to a high temperature environment of 400 ° C. or higher. A heat-resistant coating film to be maintained can be obtained.
The amide-based rocking agent (D) contained in the present composition may be one kind or two or more kinds.

The amide-based shaker (D) is not particularly limited, and examples thereof include shakers synthesized from vegetable oil fatty acids and amines.

The amide-based rocking agent (D) may be obtained by synthesizing it by a conventionally known method, or may be a commercially available product. Examples of the commercially available products include "Disparon A630-20X", "Disparon 6650" (all manufactured by Kusumoto Kasei Co., Ltd.), "AS-AT-250F" (manufactured by Itoh Oil Chemicals Co., Ltd.), and " "Fronon RCM-300TL" (manufactured by Kyoeisha Chemical Co., Ltd.) can be mentioned.

The content of the amide-based rocking agent (D) is preferable with respect to 100% by mass of the solid content of the present composition from the viewpoint that the effect of the amide-based rocking agent (D) is more exerted. Is 0.3 to 5% by mass, more preferably 1 to 2.5% by mass.

<Rust preventive pigment (E)>
By containing the rust preventive pigment (E) in this composition, it is possible to obtain a heat-resistant coating film having excellent corrosion resistance even when cured and dried at room temperature.
The rust preventive pigment (E) contained in the present composition may be one kind or two or more kinds.

The rust preventive pigment (E) is not particularly limited, and examples thereof include conventionally known rust preventive pigments. It is preferably a lead / chromium-free rust preventive pigment, more preferably a phosphate-based rust preventive pigment, and particularly preferably a zinc phosphate-based rust preventive pigment or an aluminum phosphate-based rust preventive pigment.

The rust preventive pigment (E) may be a commercially available product, and examples of the commercially available product 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 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 by mass, more preferably 3 to 8% by mass.

<Other ingredients>
If necessary, the present composition contains pigments (coloring pigments and extender pigments) other than mica (B), mica-like iron oxide (C) and rust-preventive pigment (E), and pigment dispersants, as long as the effects of the present invention are not impaired. , Anti-sagging / anti-settling agent other than defoaming agent, amide-based rocking agent (D), additives such as dehydrating agent, organic solvent, curing catalyst and the like may be contained.
These other components may be one kind or two or more kinds, respectively.

(Coloring pigment)
The coloring pigment is not particularly limited, but is preferably a coloring pigment having heat resistance, and examples thereof include Pigment Black 28 (Copper chromate black spinel), aluminum flakes, stainless flakes, titanium white, carbon black, and a valve handle. Be done.
Examples of commercially available colored pigments include "CFP-4010BK" (MnO ₂ -Fe ₂ O ₃ -CuO-Co ₃ O ₄ , manufactured by Okuno Pharmaceutical Co., Ltd.), which is a chromium-free black inorganic pigment, and aluminum. Examples thereof include "Al-Paste 0100M-C70" (manufactured by Toyo Aluminum Co., Ltd.) which is a paste.

<Constitution pigment>
The extender pigment is not particularly limited, but is preferably an extender pigment having heat resistance, and examples thereof 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 capable of uniformly dispersing the pigment in the composition to 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.).

<Defoamer>
The defoaming agent is not particularly limited, but is a material capable of suppressing the generation of bubbles during production or painting of the present composition, or a material capable of breaking bubbles generated in the present composition. Is preferable.
The defoaming 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.). ..

<Sauce prevention / sedimentation prevention agent>
The sagging prevention / sedimentation inhibitor is not particularly limited, but is a material capable of suppressing pigment sedimentation of the present composition and improving its storage stability, or a sagging prevention property of a coating composition during or after painting. It is preferable that the material can improve the above.

Examples of the anti-sagging / sedimentation inhibitor include organic rocking agents such as hydrogenated castor oil-based rocking agents and polyethylene oxide-based rocking agents, clay minerals such as bentonite, and inorganic rocking agents such as synthetic fine powder silica. Among these, clay minerals such as polyethylene oxide-based rocking agents, synthetic fine powder silica and bentonite are preferable.

The anti-sagging / sedimentation inhibitor may be a commercially available product, and the commercially available product may be, for example, "Bentone 38" (manufactured by Elementis Specialties Inc.), which is an organically modified bentonite-based viscosity modifier (hectorite / quaternary amine). ), Silicon dioxide-based shaker "Aerosil R972" (manufactured by Nippon Aerosil Co., Ltd.), polyethylene oxide-based shaker "AS-AD-120" (manufactured by Ito Oil Co., Ltd.) Can be mentioned.

The content of the anti-sagging / sedimentation inhibitor 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 it is preferably a material that can suppress a decrease in storage stability of the present composition due to excessive water content.
Examples of such a dehydrating agent include anhydrous gypsum and vinyltrimethoxysilane.

<Organic solvent>
When this composition is applied to a plant structure that is in a high temperature state during plant operation, especially a base material such as the outer surface of a pipe, the organic solvent component easily volatilizes due to the heat of the base material surface, and a good coating film is formed. It tends to be difficult. Therefore, it is preferable that the organic solvent contains an organic solvent having a relatively high boiling point. Examples of such a high boiling point organic solvent include mineral spirit and isopropyl alcohol. In addition, solvents usually used for 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 cross-linking reaction of the siloxane binder (A), for example, aminosilane, titanium alkoxide, titanium chelate, metal soap such as aluminum / zinc, and phosphorus. Examples include acids and phosphoric acid esters. Among these, metal soaps such as aluminum and zinc are preferable because the composition tends to be in a one-component form.

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

<Heat-resistant paint composition>
The pigment volume concentration (PVC: Pigment Volume Concentration) of the present composition is preferable from the viewpoints of being able to obtain a heat-resistant coating film having excellent corrosion resistance and excellent adhesion of the coating film to a substrate after heating and drying. It is 30 to 50%, more preferably 35 to 45%.
When PVC is below the above range, the corrosion resistance of the heat-resistant coating film to be formed tends to decrease, and the adhesion of the coating film after heat-drying to the substrate also tends to decrease. Further, when PVC 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 with respect to the volume of the solid content (nonvolatile content) in the present composition. Specifically, PVC can be obtained from the following formula.
PVC [%] = total volume of all pigments in the composition x 100 / volume of solids in the composition

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

The volume of the solid content in the present composition can be calculated from the mass and the true density of the solid content of the present 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 type coating composition from the viewpoint of being a composition having excellent coating workability, but is a two-component type in which the curing catalyst is mixed and stirred immediately before the start of the coating operation. It can also be used as a coating composition of.

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

The base material is not particularly limited, and for example, a metal base material made of steel (iron, steel, alloy iron, carbon steel, alloy steel, etc.), non-ferrous metal (stainless steel, aluminum, etc.), and a shop primer or the like on the surface. Examples include coated metal substrates. Examples of the base material include a plant structure, a land structure, an offshore structure, a ship, and the like, but the plant structure is preferable from the viewpoint of further exerting the effect of the present invention. Among the structures, plant piping is more preferable. As the base material, carbon steel used for plant piping, ships, and marine structures, or stainless steel such as SUS304 and SUS316L, which is preferably used for parts requiring cold resistance and heat resistance, is more preferable.

The film thickness of the heat-resistant coating film is not particularly limited as long as it is thick enough to prevent corrosion of the substrate, but is preferably 100 to 400 μm, and more preferably 150 to 280 μm.
Since this composition is used, even if a coating film having such a film thickness is formed on a substrate, swelling and cracks are unlikely to occur in the coating film, and in particular, the temperature is high at 400 ° C. or higher or a sudden temperature change. Even when exposed, swelling and cracking are unlikely to occur, so that the substrate can be protected from corrosion for a long period of time.
In consideration of corrosion resistance, a thicker film is desirable, but in the case of an excessive thick film, the residual solvent and the like contained in the coating film volatilize due to heating, which may cause swelling of the coating film. The increase in the internal stress of the coating film caused by the structural change due to the reaction or decomposition of the siloxane-based binder (A) and the components derived from the binder, and the accompanying cracks and peeling tend to occur easily.

The heat-resistant coating film is formed from the above-mentioned composition, and can be specifically produced by going through a step including the following steps [1] and [2].
[1] Step of applying the present composition to the base material [2] Step of drying the heat-resistant coating composition coated on the base material to form a heat-resistant coating film

Further, this method can form a heat-resistant coating film having better corrosion resistance and heat resistance by including the following step [3].
[3] A step of heating the coating film obtained in the above step [2] at 150 to 250 ° C.

<Step [1]>
The method for coating the present 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 and the like are preferable. Spray coating is preferable because it is excellent in workability and productivity, can be easily coated on a large-area substrate, and can further exert the effects of the present invention.
When the present composition is a two-component type composition, the main agent component and the curing promoting component (component containing the curing catalyst) may be mixed immediately before painting and spray painting or the like may be performed.

The conditions for spray coating may be appropriately adjusted according to the thickness of the heat-resistant coating film to be formed. For example, in the case of airless spray, the primary (air) pressure: about 0.4 to 0.8 MPa is secondary ( The coating conditions may be set to a pressure (paint) of about 10 to 26 MPa and a gun moving speed of about 50 to 120 cm / sec.
The viscosity of this composition used at that time is adjusted with thinner, and 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 about 2.5 Pa · s. 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, and minerals. Examples thereof include an aliphatic hydrocarbon-based solvent such as spirit and cyclohexane, and an alcohol-based solvent such as n-butanol and isopropanol. The thinner used may be one type or two or more types.

When this composition is applied to plant piping, etc., it is possible to apply it to relatively high temperature piping, etc. without stopping the operation of the plant. In this case, the spray-painted paint is uniform on the surface of the substrate. It solidifies before it becomes a smooth coating film, and it becomes easy to apply it in the form of dust. A high boiling point solvent can be used as the thinner for the purpose of suppressing this.

When the present composition is applied onto a substrate, in order to remove rust, oil, moisture, dust, salt, etc. on the substrate, and to improve the adhesion of the obtained heat-resistant coating film to the substrate. If necessary, the surface of the substrate is preferably treated (for example, blast treatment (ISO8501-1 Sa2 1/2), degreasing to remove oil and dust) and the like. Further, 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, and thus a heat-resistant coating film having excellent heat resistance and corrosion resistance can be obtained even when dried and cured at room temperature. Further, if desired, it may be dried under heating in order to shorten the drying time.
The drying conditions are not particularly limited and may be appropriately set according to the composition, the base material, the coating place, etc., but the drying temperature is preferably 5 to 40 ° C, more preferably 10 to 30 ° C. The drying time is preferably 18 hours to 14 days, more preferably 24 hours to 7 days.

<Step [3]>
By performing the above 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 more excellent corrosion resistance.
The heating conditions in the 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 for forming a heat-resistant coating film having the above-mentioned film 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. From the viewpoint of film thickness control 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 the steps [1] and [2], and if necessary, the steps [1] and [2] on the obtained coating film after performing the steps [3]. , Refers to a method of performing step [3] as necessary, and painting three or more times further refers to a method of repeating a series of steps.

When the coating film is formed by coating two or more times, for example, it is preferable that the hue of the paint / coating film to be coated first and the hue of the paint / coating film to be coated next are different. This is a measure for facilitating the judgment such as forgetting to apply or insufficient film thickness in the painting work. Further, a top coat may be applied in order to finish the final hue of the outer surface to a specified hue.

Hereinafter, the present invention will be further described with reference to Examples, but the present invention is not limited thereto.

<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-Device: "Alliance 2695" (manufactured by Waters)
-Column: One "TSKgel SuperH4000" and two "TSKgel SuperH2000" are connected (both manufactured by Tosoh Corporation, inner diameter 6 mm x length 15 cm).
-Eluent: Tetrahydrofuran 99% (Stabilized with BHT)
・ Flow velocity: 0.6 ml / min
-Detector: "RI-104" (manufactured by Shodex)
・ Column constant temperature bath temperature: 40 ° C
・ Standard substance: Standard polystyrene ・ Sample preparation method: Weigh the sample into a sample tube and add tetrahydrofuran to dilute it about 100 times.

[Example 1]
In a container, 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 are placed, and SILRES REN80 30. 3 parts by mass, 1 part by mass of Disparon 6650 and 4 parts by mass of LF Bowsei ZP-N were added and stirred with a high speed disper to uniformly disperse.
To the obtained mixture, 36.9 parts by mass of 100 mesh of mica powder was added and stirred, and the temperature of the mixture was raised to 58 ° C. by the heat generated by the stirring.
Further, 325 parts by mass of MIOX 325 mesh was added, stirred and uniformly dispersed, then cooled to 30 ° C. or lower, 1.5 parts by mass of D-15 was added, stirred and uniformly dispersed, and a 60 mesh nylon net was used. The coating composition was prepared by filtering with.

[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. The numerical values shown in the raw material column of Tables 2 to 5 indicate parts by mass.
The details of each raw material shown in Tables 2 to 5 are as shown in Table 1.
The solid content (mass%) of each component in Table 1 is a value in the manufacturer's catalog.

<Evaluation of physical properties of coating film>
(1) Unheated test Xylene was measured by measuring the viscosities of the coating compositions obtained in Examples and Comparative Examples at 23 ° C. using the B-type viscometer so that the viscosities were 2.0 Pa · s. Was adjusted using.
The viscosity-adjusted coating composition was coated on an SS400 sandblasted (corresponding to ISO8501-1 Sa2 1/2) steel sheet using a film applicator with a gap of 700 μm so that the dry film thickness was 250 μm.
Then, the coating composition coated on the steel sheet was dried at 23 ° C. for 7 days to prepare a test piece (base material with a coating film).

The obtained test pieces were evaluated according to the following evaluation criteria.
5: The appearance of the coating film is good without cracking or peeling. Good curing and drying properties.
4: There is no cracking, peeling, etc., and the appearance of the coating film is good, but adhesion remains on the surface of the coating film.
3: When a magnifying glass is used, cracks and the like are observed on the surface of the coating film.
2: Even if a magnifying glass is not used, cracks and the like are observed in a part of the coating film.
1: Occurrence of cracking and peeling is observed over the entire coating film.

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

(3) Heat shock test The test piece obtained in the same manner as in the above (1) unheated test was placed in an oven, heated at 400 ° C. for 8 hours, removed from the oven, immediately immersed in ice water for 10 seconds, and rapidly cooled. .. Then, the test piece was taken out from ice water, water droplets adhering to the test piece were removed with a paper waste cloth, and then the test piece was left at room temperature overnight. After performing this heating and quenching two more times (heating and quenching a total of three times), the obtained test pieces were evaluated according to the same evaluation criteria as in the above (1) unheated test.

(4) HRT (SUS base material)
A test piece was prepared in the same manner as in the above (1) unheated test, except that a SUS304 sand sweep (equivalent to ISO8501-1 Sa1) 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 in the same manner as in (2) HRT described above was evaluated according to the following evaluation criteria.
5: The appearance of the coating film is good without cracking or peeling.
4: Peeling is observed on a small part of the coating film (less than 5% in area).
3: Peeling is observed on a part of the coating film (5% or more and less than 20% in area).
2: Peeling is observed on the coating film corresponding to the area of 20% or more and 50% or less of the entire surface of the coating film.
1: The entire surface of the coating film is peeled off, or the entire surface of the coating film is cracked.

<Evaluation of anticorrosion>
In the evaluation of the corrosion resistance, the scratches (scribing) having a depth to the extent that a part of the steel sheet is exposed at the portion shown in FIG. ), And in order to eliminate the influence of the unpainted part of the paint composition, use the test piece whose back surface and edge part of the test piece are coated with epoxy-based anticorrosion paint, and in accordance with JIS Z 2371, on each test piece. On the other hand, a salt spray test (35 ° C.) was carried out for 3 weeks and evaluated according to the following evaluation criteria.
5: No rust is found on the evaluation target part.
4: Slight rust is observed on the evaluation target part (less than 1% in area).
3: Rust 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: Rust is observed due to peeling of the coating film and floating of the coating film.

Here, the “evaluation target portion” refers to a portion excluding the range of 1 cm from the end portion of the test piece in consideration of the influence of the epoxy-based anticorrosion paint.
The "unheated test (general part)" in Tables 3, 4 and 5 below refers to the anticorrosion test using the test piece after the (1) unheated test of the coating film physical property evaluation. Of the parts to be evaluated, the general part shown in FIG. 1 (the part excluding the range of 1 cm from the end of the test piece and the part excluding the range of 1 cm from the scribe) was evaluated. It is a test.
In the following Tables 2, 3, 4 and 5, the "unheated test (scribe portion)" means that the anticorrosion test is performed using the test piece after the (1) unheated test of the coating film physical property evaluation. This is a test in which 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 within the range of 1 cm from the scrib) among the evaluation target parts was evaluated. be.
In Table 5 below, "HRT (general part)" and "HRT (scribe part)" are the anticorrosion using the test piece after performing (2) HRT (Heat Resistant Test) of the coating film physical property evaluation. This is the test for which the test was performed. The "HRT (general part)" is a test in which the general part shown in FIG. 1 is evaluated among the evaluation target parts, and the "HRT (scribe part)" evaluates the scribe part shown in FIG. 1 among the evaluation target parts. It is a test that was done.
In the evaluation column in which "(general part)" and "(scribe part)" are not described in the anticorrosion column of Tables 3 to 5, both the general part and the scribe part shown in FIG. 1 are used as the evaluation target parts. This is the result of the evaluation.

Claims (10)

A heat-resistant coating composition containing a siloxane-based binder (A), mica (B) , mica-like iron oxide (C), and an amide-based rocking agent (D) . The heat-resistant coating composition according to claim 1, wherein the mass ratio of the mica (B) to the mica-like iron oxide (C) is in the range of 90:10 to 30:70. The heat-resistant coating composition according to claim 1 or 2, wherein the heat-resistant coating composition has a pigment volume concentration (PVC) of 30 to 50%. The siloxane-based 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 coating composition according to any one of claims 1 to 3, which comprises at least one of the above-mentioned heat-resistant coating compositions. The heat-resistant coating composition according to claim 4, wherein the siloxane binder (A) contains ethyl silicate (A3). The heat-resistant coating composition according to any one of claims 1 to 5 , further comprising a rust preventive pigment (E). A heat-resistant coating film formed from the heat-resistant coating composition according to any one of claims 1 to 6 . A base material with a heat-resistant coating film, which comprises the base material and the heat-resistant coating film according to claim 7 . The base material with a heat-resistant coating film according to claim 8 , wherein the base material is a plant structure. A method for producing a base material with a heat-resistant coating film, which comprises the following steps [1] and [2].
[1] Step of applying the heat-resistant coating composition according to any one of claims 1 to 6 to a base material [2] The heat-resistant coating composition coated on the base material is dried to form a heat-resistant coating film. Forming process

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