KR20220019109A - Heat-resistant coating composition, heat-resistant coating film, substrate with heat-resistant coating film, and manufacturing method thereof - Google Patents

Abstract

One embodiment of the present invention relates to a heat-resistant coating composition, a heat-resistant coating film, a substrate with a heat-resistant coating film, or a method for manufacturing the same, wherein the heat-resistant coating composition contains a siloxane-based binder (A), an aluminum powder (B), and a magnesium phosphate-based compound It contains a rust preventive pigment (C).

Description

Heat-resistant coating composition, heat-resistant coating film, substrate with heat-resistant coating film, and manufacturing method thereof

One embodiment of the present invention relates to a heat-resistant coating composition, a heat-resistant coating film, a substrate with a heat-resistant coating film, or a method for manufacturing the same.

In order to prevent heat dissipation to or absorption of heat from outside air and thereby suppress energy loss, a heat insulating material is provided around the pipe (steel pipe) in many cases in a pipe such as a plant structure. However, rainwater entering the gap between the insulating material and the steel (e.g., carbon steel, low alloy steel) pipe or the moisture condensed at the point forms a water film on the surface of the steel pipe, causing corrosion under the insulating material (CUI: Corrosion Under Insulation). There are cases. This CUI means that local corrosion erosion occurs by forming a corrosion cell on the surface of the steel pipe due to the water film. Since its corrosion rate is faster than the total corrosion occurring in the outdoor atmosphere, it is a big problem in the maintenance and management of plant structures.

In addition, in the CUI, since the corrosive erosion part is under the insulating material (surrounded by the insulating material), moisture that has penetrated once easily accumulates and the wet state is maintained for a long period of time, and depending on the operating conditions of the plant, the pipe is exposed to high temperature In some cases, the progress of corrosion, which is an oxidation reaction, is accelerated, and since plant structures are often installed in coastal areas rich in sea salt particles that can be corrosion factors, the sea salt particles accelerate the progress of corrosion, etc. It is also a problem that the corrosion erosion tends to become serious due to this.

Accordingly, for the purpose of preventing corrosion, etc., an anticorrosive coating film (heat-resistant coating film) is installed on the outer surface of a pipe used in a plant structure or the like. This anticorrosive coating film is provided not only under the insulating material, but also on the portion of the outer surface of the pipe where the insulating material is not provided, for the purpose of preventing the same corrosion as described above. As for the anticorrosive film installed on the outer surface of the pipe, particularly the portion where the insulating material is not installed, a silver anticorrosive film (metallic film) is favorably used in terms of designability and the like.

In addition, since piping used for plant structures, etc. is exposed to various temperature environments depending on the operating conditions of the plant, etc. Over a wide range, for example, resistance in a wide temperature range from -198°C to 500°C or more is required in some cases.

As a composition capable of forming a metallic coating film having heat resistance and corrosion resistance, Patent Document 1 discloses a coating composition containing polysiloxane, alkyl titanate, talc, and aluminum chips.

Japanese Patent Publication No. 2009-522388

In a coating composition for forming a metallic coating film, an aluminum pigment is usually used, but as the present inventors have studied earnestly, the anticorrosive coating film formed with a conventional coating composition containing an aluminum pigment may not have sufficient corrosion resistance in some cases. Could know. When a coating film (metallic coating film) is formed on a pipe, depending on the type or use of the pipe, it may not be sufficiently heat-hardened. In this case, it was found that the corrosion resistance is not particularly sufficient.

In addition, when a heat-resistant coating film is formed on each member such as a steel pipe, heating and drying (baking) may be possible in some cases, but manufacturing cost increases due to an increase in the number of steps and energy for heating. Accordingly, there is a demand for a coating composition capable of forming a heat-resistant coating film having coating film performance such as sufficient corrosion resistance required even when a coating film is formed by drying at room temperature (5 to 40° C.).

In addition, when the heat-resistant coating film formed on the outer surface of a pipe such as a plant structure that can be exposed to extremely high temperatures of 500°C or more is a thick film with a film thickness of 100 μm or more, the heat-resistant coating film swells due to repeated temperature changes in a high-temperature environment. or cracks are likely to occur. More specifically, when the heat-resistant coating film is exposed to high temperature, the residual solvent in the coating film is volatilized and the gas swells due to the reaction/decomposition of the silicone resin component constituting the coating film, and the reaction/decomposition of the silicone resin component. Cracks may occur due to an increase in the internal stress of the coating film due to, for example, the like. 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 coating material is usually less than 80 µm. It was difficult.

However, it was found that CUI is a big problem in maintenance and management in piping such as plant structures, and in the case of a thin film of less than 80 μm as described above for the severe corrosive environment, it was found that long-term corrosion resistance could not be maintained. .

One embodiment of the present invention is a heat-resistant coating film (metallic) that exhibits excellent corrosion resistance even without heating when forming the coating film, and can maintain sufficient heat resistance, corrosion resistance, and adhesion to a substrate even under a wide temperature including high temperature. A heat-resistant coating composition capable of forming a coating film) is provided.

According to the structural example below, it discovered that the said subject could be solved, and came to complete this invention.

A configuration example of the present invention is as follows.

<1> A heat-resistant paint composition comprising a siloxane binder (A), an aluminum powder (B), and a rust preventive pigment (C) containing a magnesium phosphate compound.

<2> The heat-resistant paint composition according to <1>, wherein the rust preventive pigment (C) further contains a zinc phosphate compound.

<3> The heat-resistant coating composition according to <1> or <2>, further comprising a curing accelerator (D).

<4> The heat-resistant coating composition according to any one of <1> to <3>, wherein the pigment volume concentration (PVC) is 25 to 55%.

<5> A heat-resistant coating film formed from the heat-resistant coating composition according to any one of <1> to <4>.

A base material with a heat-resistant coating film, comprising the <6> base material and the heat-resistant coating film according to <5>.

<7> A method for producing a substrate with a heat-resistant coating, comprising the steps [1] and [2] below.

[1] A step of coating the substrate with the heat-resistant coating composition according to any one of <1> to <4>

[2] A process of forming a heat-resistant coating film by drying the coated heat-resistant coating composition

According to one embodiment of the present invention, when forming a coating film, excellent corrosion resistance is exhibited even without heating, and even under a wide temperature range including high temperature (eg, 500 ° C. or higher), sufficient heat resistance, corrosion resistance and It is possible to provide a heat-resistant coating composition capable of forming a heat-resistant coating film (metallic coating film) capable of maintaining adhesion.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic plan view of the test piece which put the scribe used for anticorrosive evaluation in an Example.

《Heat-resistant paint composition》

The heat-resistant coating composition of one embodiment of the present invention (hereinafter also simply referred to as “the present composition”) contains a siloxane-based binder (A), an aluminum powder (B), and a rust preventive pigment (C) containing a magnesium phosphate-based compound. .

Since this composition contains (A) and (C) together with (B), it is a metallic coating composition containing aluminum powder, and a heat-resistant coating film having sufficient corrosion resistance even if a coating film is formed by drying at room temperature can be obtained. In addition, according to the present composition, it is a thick film with a dry film thickness of 100 μm or more, and even after exposure to a high-temperature environment exceeding 500 ° C., a heat-resistant coating film capable of maintaining corrosion resistance and adhesion to a substrate can be obtained. .

In addition, according to the composition, a heat-resistant coating film with good adhesion to stainless steel (eg SUS304, SUS316L, etc.) applied when exposure to a high temperature environment of 400° C. or higher, which has a large coefficient of linear expansion compared to carbon steel, is formed. can do.

For this reason, this composition is suitably used for the outer surface of piping, such as for plant structures, where operation under various temperature conditions is assumed and insulation is installed. used appropriately.

The composition is not particularly limited as long as it contains components (A) to (C), and according to the purpose, other additives other than (A) to (C), for example, within a range that does not impair the effects of the present invention, , a curing accelerator (D), a pigment other than the above (B) and (C), a dispersing agent, an antifoaming agent, an anti-sagging and anti-settling agent, a dehydrating agent, and an organic solvent may be included.

The present composition may be a one-component composition or a two-component composition or more.

The composition preferably contains a curing accelerator (D) from the viewpoint of easily obtaining a heat-resistant coating film excellent in corrosion resistance even by drying at room temperature, and in this case, the main agent containing (A) to (C) It is preferable to set it as a two-component type composition which consists of a component and the component containing a hardening accelerator (D).

When the present composition is a two-component or more composition, each component used in the composition is usually stored, stored, transported, etc. in separate containers, and mixed immediately before use.

<Siloxane-based binder (A)>

The siloxane 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 the siloxane-based binder (A) is used as the binder in the present composition, a heat-resistant coating film having particularly excellent heat resistance can be obtained.

The number of siloxane-type binders (A) contained in this composition may be one, and 2 or more types may be sufficient as them.

Examples of the siloxane binder (A) include compounds having 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 a condensation reaction and an addition reaction, and examples of the condensation reaction include a dehydration reaction and a dealcoholization reaction.

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

In particular, the present composition preferably contains a silicone resin (A1) as the 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 coating properties and coating film performance. Therefore, it is more preferable to use in combination with silicone oligomer (A2) and ethyl silicate (A3) having a lower weight average molecular weight.

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

[Formula I]

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

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 C6-C8 aryl group in said R< ¹ > and R< ² > may also contribute which has substituents, such as an alkyl group, on an aromatic ring, For example, a phenyl group, a methylphenyl group, and a dimethylphenyl group are mentioned.

As -OR in said R< ¹ >, a methoxy group, an ethoxy group, a propoxy group, and a phenoxy group are mentioned, for example.

The weight average molecular weight of the siloxane binder (A) in terms of standard polystyrene measured by the GPC (gel permeation chromatography) method (hereinafter simply referred to as “Mw”) is preferably 200 or more, more preferably 400 or more, Preferably it is 300,000 or less, More preferably, it is 200,000 or less.

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

The content of the siloxane binder (A) is preferably 20 mass% or more, more preferably 25 mass%, based on 100 mass% of the solid content of the present composition, from the viewpoint of obtaining a heat-resistant coating film having more excellent corrosion resistance and heat resistance. % or more, particularly preferably 35 mass% or more, preferably 60 mass% or less, more preferably 55 mass% or less, particularly preferably 50 mass% or less.

<Silicone 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 above formula (I), and R ¹ in the formula (I) is a methyl group, an ethyl group, a propyl group, or The compound which is a phenyl group is more preferable, and the compound whose R< ² > in Formula (I) is a methyl group, an ethyl group, a phenyl group, or a hydrogen atom is more preferable.

When this composition contains a silicone resin (A1), 1 type may be sufficient as this silicone resin (A1), and 2 or more types may be sufficient as it.

The silicone resin (A1) is preferably a resin having heat resistance such as methyl silicone resin or methylphenyl silicone resin, and the following dimethylsiloxane unit (a1), diphenylsiloxane unit (a2), monomethylsiloxane unit (a3), mono It is more preferable to contain at least one structural unit selected from the group consisting of a propylsiloxane unit (a4) and a monophenylsiloxane unit (a5).

(In the formulas (a1) to (a5), "-" bonded to O in Si-O- and not bonded to Si represents the number of bonds, and Si-O- is necessarily Si-O- It does not represent CH ₃ ).

Mw of the silicone resin (A1) is 15,000 or more, preferably 18,000 or more, 300,000 or less, and preferably 200,000 or less, from the viewpoint of obtaining a heat-resistant coating film having better heat resistance and corrosion resistance.

Since the silicone resin (A1) having Mw greater than the above range has a high viscosity, when handling is considered, dilution with an organic solvent or the like is necessary to lower the viscosity of the present composition including the silicone resin (A1). many. As a result, the solvent content in this composition increases, and VOC (Volatile Organic Compounds/volatile organic compound) in this composition cannot be reduced in some cases.

The silicone resin (A1) may be obtained by synthesizing it by a conventionally known synthesis method, or may be a commercially available product. As the commercial item, "SILRES REN60", "SILRES REN80" (all manufactured by Asahi Kasei Wacker Silicone Co., Ltd.), and "SILIKOPHEN P80/X" (made by Evonik) are mentioned, for example.

When the present composition contains the silicone resin (A1), the content of the silicone resin (A1) is preferable with respect to 100 mass% of the solid content of the present composition from the viewpoint of obtaining a heat-resistant coating film having more excellent corrosion resistance and heat resistance. Preferably 10 mass % or more, More preferably 15 mass % or more, Especially preferably 25 mass % or more, Preferably it is 50 mass % or less, More preferably, it is 45 mass % or less, Especially preferably 42 mass % or more. is below.

<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.

Mw of silicone oligomer (A2) is less than 15,000, Preferably it is 400 or more, Preferably it is 12,000 or less.

When this composition contains a silicone oligomer (A2), 1 type may be sufficient as this silicone oligomer (A2), and 2 or more types may be sufficient as it.

The silicone oligomer (A2) may be obtained by synthesizing it by a conventionally known synthesis method, or may be a commercially available product. As the commercial item, "SILRES MSE100" (made by Asahi Kasei Wacker Silicone Co., Ltd.) and "KR-401N" (made by Shin-Etsu Chemical Co., Ltd.) are mentioned, for example.

When the present composition contains the silicone oligomer (A2), the content of the silicone oligomer (A2) is preferable with respect to 100% by mass of the solid content of the present composition from the viewpoint of obtaining a heat-resistant coating film having better corrosion resistance and heat resistance. preferably 0.1 mass% or more, more preferably 0.2 mass% or more, particularly preferably 0.5 mass% or more, preferably 20 mass% or less, more preferably 15 mass% or less, particularly preferably 10 mass% or more is below.

<Ethyl silicate (A3)>

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

When this composition contains ethyl silicate (A3), the number of this ethyl silicate (A3) may be one, and 2 or more types may be sufficient as it.

[Formula II]

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

Ethyl silicate (A3) may be obtained by synthesizing it by a conventionally known synthesis method, or may be a commercially available product. As the commercial product, for example, "ethyl silicate 40" (manufactured by Kolcoat 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 pentamers, are used. can be heard

When the present composition contains ethyl silicate (A3), the content of this ethyl silicate (A3) is determined from the viewpoint of obtaining a coating composition excellent in coating workability, low price, and excellent dehydration effect during storage, etc., the solid content of the composition Preferably it is 1 mass % or more with respect to 100 mass %, More preferably, it is 2 mass % or more, Preferably it is 20 mass % or less, More preferably, it is 15 mass % or less.

When the present composition contains the above (A1) and/or (A2) and (A3), the total content of the silicone resin (A1) and the silicone oligomer (A2) in the present composition, and the ethyl silicate (A3) The content ratio (A1+A2:A3) is preferably 95:5 to 60:40 from the viewpoint of obtaining a heat-resistant coating film superior in heat resistance and corrosion resistance.

In addition, when this composition contains said (A1) and (A2) and/or (A3), content of silicone resin (A1) in this composition, silicone oligomer (A2), and ethyl silicate (A3) The ratio of the total content of (A1:A2+A3) is preferably 90:10 to 30:70, more preferably 90:10 to from the viewpoint of obtaining a heat-resistant coating film having more excellent heat resistance and corrosion resistance. It is 40:60.

<Aluminum powder (B)>

The aluminum powder (B) is not particularly limited, and may be a flaky aluminum powder or a non-flaky aluminum powder other than scaly. Powders are preferred. In addition, by using the flaky aluminum powder, it is also possible to form an anticorrosive coating film having superior salt water resistance, moisture resistance, and the like.

In addition, you may use not only powder form but paste form aluminum as a raw material at the time of preparing this composition.

The number of aluminum powder (B) contained in this composition may be one, and 2 or more types may be sufficient as it.

The above-mentioned "scale-like" refers to that the shape is in the form of scaly pieces, and there is no particularly prescribed range, but usually, the aspect ratio thereof is preferably 5 or more, more preferably 10 or more, and still more preferably is 20 or more, preferably 150 or less, and more preferably 120 or less.

In addition, the above-mentioned "non-scaly" refers to having a shape other than a scaly shape such as a spherical shape, a teardrop shape, a spindle shape, etc., and there is no particularly prescribed range, but usually, the aspect ratio thereof is preferably 5 It is less than, More preferably, it is 1 or more, More preferably, it is 3 or less.

The aspect ratio may be measured using an electron microscope. Using a scanning electron microscope (SEM), for example, "XL-30" (trade name; manufactured by Philips), the aluminum powder is observed, and the thickness of several ten to several hundred powder particles and the maximum length on the main surface (or It can be calculated by measuring the length of the major axis and the length of the minor axis) and obtaining an average value of these ratios (maximum length/thickness on the main surface, or length of the major axis/length of the minor axis).

In addition, the thickness of the said aluminum powder can be measured by observing in the horizontal direction with respect to the main surface (surface with the largest area) of the said aluminum powder, Moreover, the maximum length in the main surface of the said aluminum powder is, for example, a main surface If it is rectangular, it means the length of the diagonal, if the main surface is circular, it means the diameter, and if the main surface is elliptical, it means the length of the major axis. The length of the major axis of the aluminum powder is, specifically, the longest length in the cross section near the center of the powder, and the length of the minor axis of the aluminum powder is perpendicular to the major axis at the center of the cross section in the cross section is the length of the line

From the viewpoint of obtaining a coating film having more excellent corrosion resistance, the median diameter (D50) of the flaky aluminum powder is preferably 100 µm or less, more preferably 5 µm or more, and more preferably 70 ㎛ or less, particularly preferably 50 ㎛ or less.

From the viewpoint of obtaining a composition excellent in coating workability with a low VOC amount, the median diameter (D50) of the non-scaly aluminum powder is preferably 50 µm or less, more preferably 5 µm or more, and more Preferably it is 30 micrometers or less, Especially preferably, it is 15 micrometers or less.

The above D50 is an average value measured three times using a laser scattering diffraction type particle size distribution measuring device, for example, "SALD-2200" (manufactured by Shimadzu Corporation).

The flaky aluminum powder may be a ripping type or a non lip type, but it is preferable to use a ripping type from the viewpoint of suppressing deterioration of the coating film and deterioration of adhesion to the substrate. In addition, when using the said flaky aluminum powder, you may use a rip type and a non lip type together.

It is preferable that the said non-flaky aluminum powder is an aluminum powder manufactured by the atomization method (spray method).

The content of the aluminum powder (B) in the composition is preferably 5% by mass based on 100% by mass of the solid content of the present composition from the viewpoint of obtaining a metallic coating film having better corrosion resistance and adhesion to the substrate. or more, more preferably 10 mass% or more, particularly preferably 15 mass% or more, preferably 35 mass% or less, more preferably 30 mass% or less.

<Anti-rust pigment (C)>

The rust preventive pigment (C) is not particularly limited as long as it contains a magnesium phosphate-based compound.

As the present inventors have studied intensively, it is possible to form a heat-resistant coating film with excellent corrosion resistance from a metallic paint containing aluminum powder even when a coating film is formed by drying at room temperature only when a magnesium phosphate-based compound is used among rust-preventing pigments. found that

The number of the rust preventive pigments (C) contained in this composition may be one, and 2 or more types may be sufficient as them. That is, the present composition may contain two or more types of magnesium phosphate-based compounds.

Examples of the magnesium phosphate compound include magnesium phosphate, magnesium ammonium phosphate, magnesium monohydrogen phosphate, magnesium dihydrogen phosphate, magnesium phosphate calcium, magnesium cobalt phosphate, magnesium phosphate nickel, magnesium phosphate zinc phosphate, phosphoric acid. and magnesium/aluminum, silica-modified magnesium phosphate, magnesium phosphite, magnesium/aluminum phosphite, magnesium/calcium phosphite, magnesium hypophosphite, magnesium polyphosphate, magnesium tripolyphosphate, magnesium metaphosphate, and magnesium pyrophosphate.

From the viewpoint of easily obtaining a heat-resistant coating film with better adhesion to the substrate, etc., the rust preventive pigment (C) contains a zinc phosphate compound (a compound other than the magnesium phosphate compound) together with the magnesium phosphate compound. it is preferable

Examples of the zinc phosphate compound include zinc phosphate, zinc phosphite, zinc hypophosphite, zinc polyphosphate, zinc tripolyphosphate, zinc metaphosphate, zinc orthophosphate, zinc pyrophosphate, zinc phosphomolybdate, zinc phosphate and zinc silicate. , aluminum zinc phosphate, and calcium zinc phosphate.

As the rust preventive pigment (C), other rust preventive pigments other than the magnesium phosphate compound and the zinc phosphate compound may be used. , aluminum phosphate compound, calcium phosphite compound, aluminum phosphite compound, strontium phosphite compound, aluminum tripolyphosphate compound, zinc molybdate compound, aluminum molybdate compound, zinc cyanamide compound, borate compound, nitro compound , and complex oxides.

D50 measured using a laser diffraction particle size distribution measuring device (manufactured by Shimadzu Corporation, SALD-2200) of the rust preventive pigment (C) is preferable from the viewpoint of obtaining a heat-resistant coating film with better corrosion resistance. Preferably it is 0.5 micrometer or more, More preferably, it is 1 micrometer or more, Preferably it is 20 micrometers or less, More preferably, it is 15 micrometers or less.

The rust preventive pigment (C) may be a commercial item, and as a commercial item containing a magnesium phosphate compound, for example, Pigment E (manufactured by Banner Chemicals Group UK), LF Bowsay MPZ-500, LF Bowsay PMG (above, Kikuchi Color) Co., Ltd. product), NP-1802, NP-1902 (above, Toho Pigment Industries Co., Ltd. product) are mentioned, As a commercial item containing a zinc phosphate compound, LF Bowsey ZP-N (Kikuchi) is mentioned, for example. Color Co., Ltd. product) is mentioned.

The content of the rust preventive pigment (C) in the composition is preferably 0.1% by mass or more, more preferably 0.5% by mass based on 100% by mass of the solid content of the present composition from the viewpoint of obtaining a heat-resistant coating film with better corrosion resistance. It is mass % or more, Especially preferably, it is 1 mass % or more, Preferably it is 20 mass % or less, More preferably, it is 15 mass % or less, Especially preferably, it is 10 mass % or less.

The content of the magnesium phosphate compound in the present composition is preferably 0.01 mass% or more, based on 100 mass% of the solid content of the present composition, from the viewpoint of easily forming a heat-resistant coating film excellent in corrosion resistance even by drying at room temperature. Preferably it is 0.1 mass % or more, Especially preferably, it is 0.5 mass % or more, Preferably it is 15 mass % or less, More preferably, it is 10 mass % or less, Especially preferably, it is 5 mass % or less.

When the present composition contains the magnesium phosphate compound and the zinc phosphate compound, the total content of the magnesium phosphate compound and the zinc phosphate compound is , Preferably it is 0.1 mass % or more with respect to 100 mass % of solid content of this composition, More preferably, it is 0.5 mass % or more, Preferably it is 20 mass % or less, More preferably, it is 15 mass % or less.

Further, from the viewpoint of easily obtaining a heat-resistant coating film with better adhesion to the substrate, the content of the magnesium phosphate compound relative to 100 parts by mass of the zinc phosphate compound is preferably 20 parts by mass or more, more Preferably it is 30 mass parts or more, Preferably it is 80 mass parts or less, More preferably, it is 70 mass parts or less.

The content of the aluminum powder (B) in the present composition is, from the viewpoint of easily obtaining a metallic tone coating film with good balance in corrosion resistance, adhesion to the substrate, and coating film strength, the aluminum powder (B) and the rust preventive pigment With respect to 100 mass % of total content of (C), Preferably it is 50 mass % or more, More preferably, it is 60 mass % or more, Especially preferably, it is 70 mass % or more, Preferably it is 99 mass % or less, More preferably It is 90 mass % or less, Especially preferably, it is 80 mass % or less.

The content of the magnesium phosphate compound in the composition is 100 mass in total of the aluminum powder (B) and the magnesium phosphate compound from the viewpoint that a metallic heat-resistant coating film having excellent corrosion resistance can be easily formed even by drying at room temperature. %, preferably 0.1 mass% or more, more preferably 0.5 mass% or more, particularly preferably 1 mass% or more, preferably 30 mass% or less, more preferably 20 mass% or less, particularly preferably is 15% by mass or less.

When the present composition contains a zinc phosphate-based compound, the content of the zinc phosphate-based compound in the present composition is determined from the viewpoint of easily obtaining a metallic heat-resistant coating film having better adhesion to the substrate, such as aluminum powder (B ) and the zinc phosphate compound in a total content of 100 mass%, preferably 0.1 mass% or more, more preferably 0.5 mass% or more, particularly preferably 1 mass% or more, preferably 40 mass% or less, more Preferably it is 30 mass % or less, Especially preferably, it is 25 mass % or less.

<curing accelerator (D)>

The curing accelerator (D) is not particularly limited, but is preferably a material having an effect of accelerating the crosslinking reaction of the siloxane binder (A), for example, aminosilane; titanium alkoxide, titanium chelate, etc. Curing catalyst; Aluminum-based curing catalyst such as aluminum metal soap; Zinc-based curing catalyst such as zinc metal soap; Phosphoric acid-based curing catalyst such as phosphoric acid and phosphoric acid ester; Dibutyltin dilaurate, dibutyltin diacetate, etc. Tin-based curing catalysts; Bismuth-based curing catalysts such as bismuth 2-ethylhexanoate and bismuth naphthenate; and lithium-based curing catalysts such as lithium decanoate. Among these, aminosilane is preferable from the viewpoint of easily obtaining a heat-resistant coating film having more excellent corrosion resistance when the composition is dried at room temperature. Moreover, it is also preferable that it is a mixture of aminosilane and alcohol.

As said aminosilane, an amino-group containing silane coupling agent is preferable. The silane coupling agent is not particularly limited, and a conventionally known compound can be used, but it is preferably a compound that has at least two functional groups in the same molecule and can contribute to the improvement of the adhesion to the substrate, for example, : 「X-SiMe _n Y _3-n 」[n is 0 or 1, and X is a group containing an amino group capable of reacting with an organic substance (eg, an amino group, a group in which a part of the hydrocarbon group is substituted with an amino group, or a hydrocarbon group) A group in which a part of the group is substituted with an ether bond or the like is partially substituted with an amino group.), Me is a methyl group, and Y is a hydrolyzable group (eg, an alkoxy group such as a methoxy group or an ethoxy group).] It is more preferable that it is a compound represented by

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

When the present composition contains a curing accelerator (D), the content of the curing accelerator (D) is 100 mass solid content of the present composition from the viewpoint that a heat-resistant coating film excellent in corrosion resistance can be easily formed even by drying at room temperature. %, Preferably it is 0.01 mass % or more, More preferably, it is 0.5 mass % or more, Preferably it is 5 mass % or less, More preferably, it is 3 mass % or less.

<Other additives>

The composition is not particularly limited as long as it contains the above (A) to (C), and depending on the purpose, within a range that does not impair the effects of the present invention, for example, other than the above (B) and (C) It may contain other additives, such as a pigment (eg constitution pigment, a coloring pigment), a dispersing agent, an antifoamer, a sagging inhibitor/settling inhibitor, a dehydrating agent, and an organic solvent.

The number of these other additives may be one, respectively, or 2 or more types may be sufficient as them.

<Other Pigments>

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.

When the present composition contains an extender pigment, the content of the extender pigment is preferably 10 mass% based on 100 mass% of the solid content of the present composition from the viewpoint of easily forming a heat-resistant coating film having more excellent corrosion resistance. % or more, more preferably 15 mass% or more, preferably 40 mass% or less, more preferably 35 mass% or less.

The color pigment is not particularly limited, but is preferably a color pigment having heat resistance, and examples thereof include Pigment Black 28 (Copper chromite black spinel), stainless flakes, titanium bag, carbon black, and Bengala.

The other pigments are preferably used in an amount such that the pigment volume concentration (PVC: Pigment Volume Concentration) in the present composition falls within the following range.

PVC in the present composition is preferably 25% or more, more preferably 30% or more, and preferably 55% or more, from the viewpoint of obtaining a heat-resistant coating film having better corrosion resistance and better adhesion to the substrate. % or less, more preferably 50% or less, still more preferably 45% or less, still more preferably 43% or less, particularly preferably 40% or less.

When the PVC content is less than the above range, the corrosion resistance of the formed heat-resistant coating film tends to decrease, and the adhesion of the formed coating film to the substrate tends to decrease. Moreover, when PVC exceeds the said range, there exists a tendency for the corrosion resistance of the heat-resistant coating film to be formed to fall.

The PVC refers to the total volume concentration of all pigments, including the above (B), (C) and other pigments, relative to the volume of the solid content (non-volatile matter) in the composition, specifically, it can be obtained by the following formula have.

PVC [%] = the total volume of all pigments in the present composition x 100/volume of the solid content in the present composition

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

The volume of the solid content in the present composition can be calculated from the mass and true density of the solid content of the composition. The mass and true density of the solid content may be measured values or values calculated from the raw materials to be used.

The volume of the pigment can be calculated from the mass and true density of the pigment used. Even if the mass and true density of the said pigment are measured values, it does not matter even if it is the value computed from the raw material to be used. For example, it can calculate by isolate|separating a pigment and other components from the solid content of this composition, and measuring the mass and true density of the separated pigment.

<Dispersant>

Although it does not restrict|limit especially as said dispersing agent, It is preferable that it is a dispersing agent which can disperse|distribute the said (B) and (C) and another pigment uniformly, and can prepare a stable dispersion.

A commercial item may be sufficient as the said dispersing agent, and as the commercial item, "Disperbyk-180" and "Disperbyk-2022" (both are made by Big Chemie Japan Co., Ltd.) are mentioned, for example.

<Antifoamer>

Although it does not restrict|limit especially as said antifoamer, It is preferable that it is a material which can suppress the generation|occurrence|production of a bubble at the time of manufacture of this composition or coating, or a material which can break the bubble generated in this composition.

A commercial item may be sufficient as the said antifoamer, and as the commercial item, "BYK-320", "BYK-066N", and "BYK-1790" (all are made by Big Chemie Japan Co., Ltd.) are mentioned, for example.

<Anti-sagging, anti-settling agent>

The anti-sagging / anti-settling agent is not particularly limited, but the anti-sagging properties of the material (B) or (C), which can suppress sedimentation of other pigments, and improve the storage stability thereof, or the coating composition during or after painting It is preferable that it is a material that can improve the

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

In particular, by containing an amide-based thixotropic agent, thixotropic properties are excellent, and according to the composition containing the amide-based thixotropic agent, a thick film with a dry film thickness of 100 μm or more can be easily formed by one coating, and at the same time, the coating target Even if the substrate is stainless steel such as SUS304 or SUS316L, it is excellent in adhesion to the substrate and, even after exposure to a high temperature environment of 400° C. or higher, a heat-resistant coating film maintaining excellent adhesion can be easily obtained.

Examples of the amide-based thixotropic agent include a thixotropic agent synthesized from vegetable oil fatty acids and amines.

A commercial item may be sufficient as the said anti-sagging / anti-settling agent, and as the commercial item, "Disparon A630-20X", "Disparon 6650" which are an amide type thixotropic agent (all are made by Kusumoto Chemical Co., Ltd.), for example. , "ASA T-250F" (manufactured by Ito Oil Chemicals Co., Ltd.), "Flownon RCM-300TL" (manufactured by Kyoeisha Chemical Co., Ltd.), organically modified bentonite-based viscosity modifier (hectorite/quaternary amine) ), “Bentone 38” (manufactured by Elementis Specialties Inc.), “Aerosil R972” (manufactured by Aerosil, Japan), a silicon dioxide-based thixotropic agent, “ASA D-120” (Ito Oil), a polyethylene oxide-based thixotropic agent Chemicals Co., Ltd. product) is mentioned.

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

<Organic solvent>

When the present composition is applied to a plant structure in a high temperature state during plant operation, particularly a substrate such as the outer surface of a pipe, the organic solvent component is easily volatilized due to the heat of the substrate surface, making it difficult to form a good coating film. For this reason, it is preferable that the organic solvent of a comparatively high boiling point is included as said organic solvent. As such a high boiling point organic solvent, mineral spirit (turpentine) and isopropyl alcohol are mentioned, for example. In addition, solvents normally used for paints can be applied. As such an organic solvent, xylene, toluene, and n-butanol are mentioned, for example.

<<Heat-resistant coating film and substrate with heat-resistant coating film>>

The heat-resistant coating film of one embodiment of the present invention (hereinafter also referred to as "this heat-resistant coating film") is formed of the present composition described above, and the substrate with a heat-resistant coating film of one embodiment of the present invention is a laminate comprising the present heat-resistant coating film and a substrate. it's a chain

The substrate is not particularly limited, and for example, a metal substrate made of steel (iron, steel, ferroalloy, carbon steel, alloy steel, etc.), nonferrous metal (aluminum, etc.), stainless steel, and a metal substrate whose surface is coated with a shop primer or the like. can be heard In addition, although plant structures, land structures, offshore structures, ships, etc. are mentioned as said base material, from the viewpoint of exhibiting the effect of this invention more, Preferably it is a plant structure, Among plant structures, plant piping is more preferable. As said base material, carbon steel used especially for plant piping, a ship, and an offshore structure, or stainless steel, such as SUS304 and SUS316L used suitably for the site|part requiring cold resistance and heat resistance, is more preferable.

The thickness of the heat-resistant coating film is not particularly limited as long as it is a thickness that can rust the substrate, but is preferably 30 µm or more, more preferably 50 µm or more, still more preferably 100 µm or more, particularly preferably 150 µm or more. It is more than micrometer, Preferably it is 400 micrometers or less, More preferably, it is 280 micrometers or less.

Since the present composition is used, even if a coating film of such a film thickness is formed on the substrate, swelling (blister) or cracks are unlikely to occur in the coating film, and in particular, it swells even when exposed to a high temperature of 500°C or more or a sudden temperature change. However, since cracks are less likely to occur, the substrate can be corroded over a long period of time.

In addition, a thicker film is preferable in consideration of corrosion resistance, but in the case of an excessively thick film, the residual solvent contained in the film is volatilized by heating, so that swelling occurs in the film, or the siloxane-based binder (A) or its binder origin There is a tendency for increased internal stress of the coating film caused by structural changes due to reaction or decomposition of components, and cracks and peeling accompanying it tend to occur.

This heat-resistant coating film is formed of the present composition described above, and specifically, it can be manufactured by going through a process including the following processes [1] and [2].

[1] Step of coating the present composition on the substrate

[2] A process of forming a heat-resistant coating film by drying the heat-resistant coating composition coated on the substrate

In addition, this method can form a heat-resistant coating film having more excellent corrosion resistance and heat resistance by including the following step [3].

[3] A step of heating the heat-resistant coating film obtained in the step [2]

<Process [1]>

The method for coating the composition on the substrate is not particularly limited, and any conventionally known method can be used without limitation, and commonly used airless spray coating, air spray coating, brush coating, roller coating, etc. are preferable. It is excellent in workability|operativity, productivity, etc., and spray coating is preferable from a viewpoint of being able to coat easily with respect to a large-area base material, and being able to exhibit the effect of this invention more.

In addition, when the present composition is a two-component composition containing a curing accelerator, it is preferable to spray coating or the like by mixing the main component and the component containing the curing accelerator immediately before coating.

The spray coating conditions may be appropriately adjusted according to the thickness of the heat-resistant coating film to be formed. For example, in the case of airless spray, primary (air) pressure: about 0.4 to 0.8 MPa, secondary (paint) pressure: 10 to It is sufficient to set the coating conditions to about 26 MPa and the gun movement speed: about 50 to 120 cm/sec.

The viscosity of the present composition used at this time may be adjusted with a thinner or the like, and the viscosity at that time is about 1.8 to 2.5 Pa·s at 23° C. when measured with a B-type viscometer (“TVB-10M, manufactured by Toki Sangyo Co., Ltd.)” is preferable The thinner is preferably an organic solvent capable of dissolving or dispersing the components in the composition, for example, an aromatic hydrocarbon solvent such as toluene and xylene, an aliphatic hydrocarbon solvent such as mineral spirit and cyclohexane, n-butanol, isopropanol, etc. of alcohol-based solvents. The number of thinners to be used may be one, and 2 or more types may be sufficient as them.

When the composition is applied to plant piping, etc., it is also possible to paint relatively high temperature piping without stopping the operation of the plant. It becomes easy to be painted in the form of dust. For the purpose of suppressing this, as the thinner, a high boiling point organic solvent can be used.

When the composition is coated on 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, the surface of the substrate is treated ( For example, it is preferable to perform a blasting process (ISO8501-1 Sa2 1/2), a process which removes the oil content by degreasing, and dust) etc. Moreover, you may apply a shop primer etc. to the said base material for the purpose of primary rust prevention.

As a method of forming a heat-resistant coating film of the above-mentioned thickness, a coating film of a desired film thickness may be formed by one coating, or a coating film of a desired film thickness may be formed by two or more coatings (applying two or more times). When the viewpoint of film thickness management and the residual solvent in a coating film are considered, it is preferable to form the coating film of the target film thickness by coating twice or more.

In addition, after performing the process [1] and [2] and, if necessary, the process [3] with two coats (coating twice), the process [1] and [2], and a process as needed on the obtained coating film It refers to the method of performing [3], and coating 3 or more times refers to a method of repeating a series of additional processes.

In the case of forming a coating film by two or more coatings, it is preferable that, for example, the hue of the paint/film applied the first time and the hue of the paint/film applied next are different. This is a measure for facilitating the judgment of a case of forgetting and not painting or insufficient film thickness in the painting operation. In addition, a top coat may be applied to finish the final outer surface with a specified color.

<Process [2]>

The composition can be dried and cured at room temperature, and even if it is dried and cured at room temperature in this way, a heat-resistant coating film having excellent heat resistance and corrosion resistance can be obtained. Moreover, you may dry under heating for shortening of drying time depending on the objective.

The drying conditions are not particularly limited, and may be appropriately set depending on the composition, substrate, and coating location, etc., but the drying temperature is preferably 5° C. or higher, more preferably 10° C. or higher, preferably 40° C. or lower, more Preferably it is 30 degrees C or less. The drying time is preferably 18 hours or more, more preferably 24 hours or more, preferably 14 days or less, more preferably 7 days or less.

<Process [3]>

By performing the above step [3], it is possible to form a heat-resistant coating film that is physically and chemically more resistant. That is, it becomes possible to form a heat-resistant coating film having a 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 or more, more preferably 30 minutes or more, and preferably It is 3 hours or less, More preferably, it is 1 hour or less.

Example

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

[Examples 1 to 9 and Comparative Examples 1 to 2]

The main component was prepared by adding each raw material described in the subject item of Table 1 to a container in the amount (parts by mass) shown in Table 1, stirring with a high-speed disper, and uniformly dispersing.

In addition, the detail of each component described in Table 1 is as showing in Table 2. In addition, solid content (mass %) of each component in Table 2 is a manufacturer's catalog value.

<Adhesiveness evaluation>

A coating composition was obtained by mixing 100 parts by mass of the prepared main component and 1.5 parts by mass of KP-390 as a curing accelerator, and the obtained coating composition was placed on an SS400 sandblasted (equivalent to ISO8501-1 Sa2 1/2) steel plate, with an interpole spacing of 700 μm. Using a film applicator, it applied so that a dry film thickness might be set to 250 micrometers.

The test piece (substrate with a coating film) was produced by drying the coating composition coated on the steel plate at 23 degreeC for 7 days. In addition, in order to eliminate the influence of the uncoated part of the coating composition, a neutral salt spray test (35 ° C. ) for 3 weeks, followed by washing with water and then drying for one day in an environment of a temperature of 23°C and a humidity of 55%, a checkered tape peeling test (5 mm×5 mm, 9 columns) was performed.

The checkered tape peeling test was specifically performed as follows.

After drying, on the coating film of the test piece, while using a cutter guide, 4 vertical × 4 horizontal cut lines of the depth reaching the steel plate were drawn to prepare 9 grids. In addition, the space|interval of the cut line was 5 mm. Next, Cellotape (registered trademark) was strongly pressed against the checkered portion of the coating film, and the ends of the Cellotape were peeled off at a time at an angle of 90° with respect to the coating film surface. Thereafter, the residual area ratio (%), which is the area of the coating film remaining on the steel sheet with respect to the area of the 9 cells, was calculated, and the value of the residual area ratio (%) was used to evaluate the adhesiveness.

The case where the residual area ratio (%) was less than 50 % was made into defective (x), and the case where the residual area ratio (%) was 50 % or more was made into favorable (circle) adhesiveness.

<Anti-corrosion evaluation>

Test pieces were prepared as shown in (1) to (3) below, and each test piece was used for evaluation by performing the salt spray test in (4) below.

(1) Unheated test piece

A coating composition was obtained by mixing 100 parts by mass of the prepared main component and 1.5 parts by mass of KP-390 as a curing accelerator, and the obtained coating composition was measured with a B-type viscometer and the viscosity at 23° C. was 2 Pa·s As much as possible, it was adjusted using xylene.

The coating composition after viscosity adjustment was applied on an SS400 sandblasted (equivalent to ISO8501-1 Sa2 1/2) steel sheet using a film applicator with a gap of 700 µm to obtain a dry film thickness of 250 µm.

Then, the coating composition coated on the steel plate was dried at 23 degreeC for 7 days, and the unheated test piece (substrate with a coating film) was produced.

(2) Heat cycle test piece (300°C heating + rapid cooling)

The test piece obtained in the same manner as the above (1) unheated test piece was placed in an electric oven, heated at 300° C. for 1.5 hours, taken out of the oven, and immediately immersed in ice water for 10 seconds, followed by rapid cooling. Thereafter, the test piece was taken out of the ice water and left to stand at room temperature for 30 minutes. Heat cycle test piece was produced by making this heating and quenching into 1 cycle, and carrying out 3 cycles.

(3) Heat resistance test piece (heated to 550°C)

The test piece obtained by carrying out similarly to said (1) unheating test was put into a muffle furnace, and after heating at 550 degreeC for 4 hours, it stood to cool, and produced the heat resistance test piece.

(4) Salt spray test

In each of the test pieces prepared in (1) to (3) above, at the location shown in Fig. 1, a scratch (scribe) having a depth enough to expose a part of the steel plate was placed, and the effect of the portion not coated with the coating composition was further reduced. In order to eliminate it, using a test piece coated with an epoxy-based anticorrosive paint on the back and edge of the test piece, a salt spray test (35° C.) was performed on each test piece for 3 weeks in accordance with JIS Z 2371, and the creep width (coating and Among the parts where the steel sheet is peeled off, the length between the point farthest from the scribe part and the scribe part) was measured and evaluated according to the following evaluation criteria. In addition, the "evaluation target part" here refers to the part excluding the range of 1 cm from the edge part of a test piece in consideration of the effect of an epoxy-type anticorrosive paint.

·Evaluation standard

(double-circle): The creep width in the part to be evaluated is less than 5 mm

(circle): Creep width in the part to be evaluated 5 mm or more and less than 10 mm

(triangle|delta): The creep width in the part to be evaluated is 10 mm or more and less than 20 mm

x: The creep width in the part to be evaluated is 20 mm or more

Claims (7)

A heat-resistant paint composition comprising a siloxane-based binder (A), an aluminum powder (B), and a rust preventive pigment (C) containing a magnesium phosphate-based compound. The method of claim 1,
The anti-rust pigment (C) further contains a zinc phosphate-based compound, a heat-resistant paint composition. 3. The method of claim 1 or 2,
A heat-resistant coating composition further comprising a curing accelerator (D). 4. The method according to any one of claims 1 to 3,
A heat-resistant coating composition having a pigment volume concentration of 25 to 55%. A heat-resistant coating film formed from the heat-resistant coating composition according to any one of claims 1 to 4. A substrate with a heat-resistant coating comprising a substrate and the heat-resistant coating according to claim 5. A method for producing a substrate with a heat-resistant coating film, comprising the steps [1] and [2] below.
[1] A step of coating the substrate with the heat-resistant coating composition according to any one of items 1 to 4
[2] A process of forming a heat-resistant coating film by drying the coated heat-resistant coating composition

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