Rust-proof paint composition, rust-proof paint film, painted article, and method for producing same

Abstract

This rust-proof paint composition contains a binder (A), a zinc powder (B), and a glass powder (C) having a thermal expansion coefficient of at least 120×10-7 / °C.

Description

Anti-rust paint composition, anti-rust coating film, coated product and method for producing the same

[0001] The present disclosure relates to an anti-rust coating composition, an anti-rust coating film, a coated article, and a method for producing the same.

[0002] For the purpose of inhibiting rust on large steel structures such as ships, marine structures, plants, tanks, and bridges, the substrate surfaces are usually coated with an anti-rust coating composition. Known examples of anti-rust coating compositions include organic anti-rust coating compositions such as wash primers, non-zinc epoxy primers, and epoxy zinc-rich primers, as well as inorganic zinc anti-rust coating compositions containing a siloxane binder and zinc powder. Among these, inorganic zinc anti-rust coating compositions are widely used (see, for example, Patent Documents 1 to 3).

[0003] International Publication No. 2016 / 047479 International Publication No. 2016 / 047480 Japanese Patent Application Laid-Open No. 53-119932

[0004] Substrates coated with an inorganic zinc paint composition may be subjected to heat treatment involving high temperatures, such as welding or cutting. In coating films formed from conventional inorganic zinc paint compositions, the zinc in the coating film tends to be oxidized and partially deactivated by such heat treatment, resulting in a decrease in rust prevention properties. Therefore, there is a demand for an anti-rust coating composition that can form a coating film that exhibits high rust prevention properties even when heated at high temperatures.

[0005] An object of the present disclosure is to provide an anti-rust coating composition that can form a coating film that exhibits high anti-rust properties even when heated at high temperatures.

[0006] One embodiment of the anti-rust coating composition of the present disclosure comprises a binder (A), a zinc-based powder (B), and a 120×10 -7 and (C) a glass powder having a thermal expansion coefficient of 100 / °C or more.

[0007] The anti-rust coating composition of the present disclosure can form a coating film that exhibits high anti-rust properties even when heated at high temperatures.

[0008] One or more of each of the components described herein can be used. In this specification, the numerical range n1 to n2 means a numerical range of n1 or more and n2 or less when n1<n2, and means a numerical range of n2 or more and n1 or less when n1>n2. In this specification, when multiple lower limit values ​​and multiple upper limit values ​​are listed for a certain element, a numerical range formed by combining a value arbitrarily selected from the listed lower limit value and a value arbitrarily selected from the listed upper limit value is also considered to be listed.

[0009] [Anti-rust coating composition] The anti-rust coating composition of the present disclosure (hereinafter also referred to as the "composition of the present disclosure") contains: a binder (A), a zinc-based powder (B), and a glass powder (C). Hereinafter, a coating film formed from the composition of the present disclosure will also be referred to as the "anti-rust coating film of the present disclosure."

[0010] <Binder (A)> The composition of the present disclosure contains binder (A). Examples of binder (A) include silicon-based binders such as siloxane-based binders, butyral resins such as polyvinyl butyral resins, and (meth)acrylic resins. Among these, silicon-based binders are preferred, and siloxane-based binders are more preferred.

[0011] Examples of siloxane binders include alkoxysilane condensates, specifically partial hydrolysis condensates of alkoxysilanes and / or their low condensates. Alkoxysilanes and / or their low condensates are also called alkyl silicates. Examples of alkoxysilanes include tetraalkoxysilanes and alkylalkoxysilanes.

[0012] Examples of tetraalkoxysilanes include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, and tetra-sec-butoxysilane. Examples of alkylalkoxysilanes include alkyltrialkoxysilanes. Examples of alkyltrialkoxysilanes include methyltrialkoxysilanes such as methyltrimethoxysilane and methyltriethoxysilane; and ethyltrialkoxysilanes such as ethyltrimethoxysilane and ethyltriethoxysilane. The number of carbon atoms in the alkoxy group contained in the alkoxysilane is preferably 1 to 5, more preferably 1 to 3. The number of carbon atoms in the alkyl group contained in the alkylalkoxysilane is preferably 1 to 5, more preferably 1 to 3.

[0013] Examples of low condensates of alkoxysilane include low condensates of tetraalkoxysilane, such as methyl polysilicate and ethyl polysilicate. Low condensates refer to condensates having a condensation degree of 2 to 20 (2 to 20 silicon atoms), preferably 3 to 10 (3 to 10 silicon atoms).

[0014] Among the alkoxysilane condensates, condensates of tetraalkoxysilane and / or its low condensates are preferred, condensates of tetraethoxysilane and / or its low condensates are more preferred, and a partial hydrolysis condensate of Ethyl Silicate 40 (trade name; manufactured by Colcoat Co., Ltd.), which is a low condensate of tetraethoxysilane, is particularly preferred.

[0015] The weight-average molecular weight (Mw) of the siloxane binder is preferably 1,300 to 10,000, more preferably 1,400 to 8,000, and even more preferably 1,500 to 6,000. When the Mw is within this range, the paint can be cured at room temperature (e.g., 5 to 40°C) in a short time when drying, and the rust resistance of the coating film and the adhesive strength to the substrate and topcoat coating tend to be improved. When the Mw is equal to or greater than the lower limit, the curing reaction of the siloxane binder is fast, and even when curing in a short time is required, high-temperature heat curing (e.g., 200 to 400°C) is not required when drying the coating film. When the Mw is equal to or less than the upper limit, the coating film tends to have excellent rust resistance.

[0016] The weight average molecular weight (Mw) of the siloxane binder is measured by gel permeation chromatography (GPC). The value obtained by GPC is a value (polystyrene equivalent) obtained using a calibration curve prepared using polystyrene as the standard substance.

[0017] The measurement conditions for the GPC method are as follows: A small amount of binder sample is taken and diluted with tetrahydrofuran, and the solution is further filtered through a membrane filter to obtain a GPC measurement sample. Apparatus: Eco SEC Elite HLC-8420GPC manufactured by Tosoh Corporation Column: TSKgel Super H4000, TSKgel Super H2000, TSKgel Super H2000 manufactured by Tosoh Corporation. The above three columns are connected in series for measurement. Eluent: tetrahydrofuran (THF) Flow rate: 0.6 ml / min Column thermostat temperature: 40°C Standard material: polystyrene

[0018] The siloxane binder can be produced by a conventionally known method, for example, by subjecting an alkoxysilane and / or a low condensate thereof to a partial hydrolysis and condensation reaction in an organic solvent in the presence of an appropriate amount of water and, if necessary, a catalyst, so that the weight-average molecular weight (Mw) reaches a desired value.

[0019] Examples of the organic solvent include those described in the section <Organic Solvent> below. The amount of water used is preferably 5 to 20 parts by mass, more preferably 6 to 18 parts by mass, per 100 parts by mass of the alkoxysilane and / or its low condensate.

[0020] Examples of the catalyst include inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, and formic acid; organic tin compounds such as dibutyltin dilaurate, dibutyltin dimaleate, dioctyltin dilaurate, dioctyltin dimaleate, dioctyltin maleate, and tin octoate; and phosphates such as phosphoric acid, monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, monooctyl phosphate, monodecyl phosphate, dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, and didecyl phosphate. Examples of suitable organic acids include phosphoric acid or phosphoric acid esters; organic titanate compounds such as diisopropoxybis(acetylacetate)titanium and diisopropoxybis(ethylacetoacetate)titanium; organic aluminum compounds such as tris(ethylacetoacetate)aluminum and tris(acetylacetonato)aluminum; and organic zirconium compounds such as tetrabutyl zirconate, tetrakis(acetylacetonato)zirconium, tetraisobutyl zirconate, and butoxytris(acetylacetonato)zirconium. Among these, inorganic acids are preferred, and hydrochloric acid is more preferred, in view of the good storage stability of the first agent described below.

[0021] When a catalyst is used, the amount thereof is preferably 0.01 to 2.0 parts by mass, more preferably 0.01 to 1.0 part by mass, per 100 parts by mass of the alkoxysilane and / or its low condensate.

[0022] The binder (A) may be one type or two or more types. The content of the binder (A) is preferably 1 to 30 mass%, more preferably 2 to 25 mass%, even more preferably 3 to 20 mass%, and particularly preferably 5 to 15 mass%, of the solid content of the composition of the present disclosure. The content of components derived from the binder (A) is preferably 1 to 30 mass%, more preferably 2 to 25 mass%, even more preferably 3 to 20 mass%, and particularly preferably 5 to 15 mass%, of the rust-preventive coating film formed from the composition of the present disclosure. When the binder (A) is a siloxane-based binder, the content of the binder (A) or components derived therefrom is calculated by converting the mass of the siloxane-based binder to the mass of SiO2 (i.e., converting the mass of the siloxane-based binder to the mass of SiO2 equivalent to the moles of Si atoms contained in the siloxane-based binder).

[0023] The solid content of a substance (e.g., a composition or a contained ingredient) refers to the heating residue when the substance is dried in an incubator at 125°C for 1 hour in accordance with JIS K5601-1-2:2008. Specifically, the heating residue is the residue of the sample (including the residue adhering to the wire) obtained by weighing out 1.0 g of the substance sample onto a flat-bottomed dish, spreading it evenly using a wire of known mass, and drying it in an incubator at 1 atmosphere and 125°C for 1 hour.

[0024] <Zinc-based powder (B)> The composition of the present disclosure contains zinc-based powder (B). The zinc-based powder (B) acts, for example, as an anti-rust pigment that inhibits rusting of steel materials.

[0025] Examples of the zinc-based powder (B) include zinc powder and zinc alloy powder. Examples of the zinc alloy include an alloy of zinc and at least one selected from the group consisting of aluminum, magnesium, and tin, specifically an alloy of zinc and aluminum, and an alloy of zinc and tin.

[0026] The shape of the particles constituting the zinc-based powder (B) can be, for example, spherical, flaky, or other various shapes. That is, the zinc-based powder (B) can be, for example, a spherical zinc-based powder or a flaky zinc-based powder. As the zinc-based powder (B), one or both of zinc powder and zinc alloy powder can be used.

[0027] The particles constituting the scaly zinc-based powder preferably have a median diameter (D50) of 30 μm or less and an average thickness of 1 μm or less, more preferably a D50 of 5 to 20 μm and an average thickness of 0.2 to 0.9 μm. The aspect ratio (D50 / average thickness), which is the ratio of D50 to average thickness, is preferably 10 to 150, more preferably 20 to 100.

[0028] The particles constituting the spherical zinc-based powder preferably have a D50 of 2 to 15 μm, more preferably 2 to 7 μm. The aspect ratio of the particles constituting the spherical zinc-based powder is preferably 1 to 3. Spherical zinc-based powder is cheaper than flaky zinc-based powder, and its use can reduce the cost of the coating composition.

[0029] The median diameter is calculated from a volumetric particle size distribution obtained using a laser scattering diffraction particle size distribution analyzer, for example, "SALD 2200" (trade name; manufactured by Shimadzu Corporation). The average thickness is calculated by observing the zinc-based powder using a scanning electron microscope (SEM), for example, "XL-30" (trade name; manufactured by Philips), measuring the thicknesses of several tens to several hundreds of powder particles, and calculating the average value.

[0030] The zinc-based powder (B) may be one type or two or more types. The content of the zinc-based powder (B) in the solid content of the composition of the present disclosure or in the rust-preventive coating film formed from the composition is preferably 10 to 90 mass%, more preferably 20 to 80 mass%, and even more preferably 25 to 70 mass%. Such a composition can form a coating film with excellent rust prevention properties and weldability.

[0031] <Glass Powder (C)> The composition of the present disclosure contains glass powder (C). It is believed that the glass powder (C) acts as a component that inhibits oxidation of the zinc-based powder (B) when the coating film is heated at high temperatures (e.g., 400 to 900°C) and contributes to maintaining the rust prevention properties of the coating film.

[0032] The glass powder (C) is 120 × 10 -7 / °C or more. For example, a substrate coated with an inorganic zinc paint composition may be subjected to a heat treatment involving high heat, such as welding or cutting. The composition of the present disclosure can form a coating film that exhibits high rust prevention properties even when placed outdoors or in a corrosive environment after high-temperature heat treatment. In other words, the rust-preventive coating film of the present disclosure exhibits high rust prevention properties even when placed outdoors or in a corrosive environment after high-temperature heat treatment.

[0033] The reason why the composition of the present disclosure exhibits such excellent effects is not clear, but the inventors speculate as follows. The thermal expansion coefficient mentioned above is the rate at which the length of a substance increases when the temperature rises. The thermal expansion coefficient is a physical property inherent to a substance. For example, when two materials with similar thermal expansion coefficients are bonded together, they tend to expand or contract in response to a temperature change. On the other hand, when two materials with large differences in thermal expansion coefficients are bonded together, they tend to peel off when a temperature change occurs. The glass powder (C) is 120 × 10 -7 The thermal expansion coefficient of the glass powder (C) is 120×10 -7 / ° C., the thermal expansion coefficient of the glass powder (C) is relatively close to that of the zinc-based powder (B). This means that the glass powder (C) can easily follow the expansion or contraction of the zinc-based powder (B) due to temperature changes, and the glass powder (C) can cover the surface of the zinc-based powder (B) during heat treatment and subsequent cooling treatment, thereby effectively suppressing its oxidation. Therefore, even if placed outdoors or in a corrosive environment after high-temperature heat treatment, the rust-preventive coating film of the present disclosure exhibits high rust prevention properties. However, the above explanation is speculation and does not limit the contents of the present disclosure in any way.

[0034] The composition of the present disclosure can form a coating film that is resistant to discoloration when subjected to heat treatment at high temperatures. That is, the rust-preventive coating film of the present disclosure exhibits heat discoloration resistance, i.e., is resistant to discoloration (small change in hue) when subjected to heat treatment at high temperatures.

[0035] The composition of the present disclosure can form a coating film that is resistant to white rust even when placed outdoors or in a corrosive environment after high-temperature heat treatment. In other words, the rust-preventive coating film of the present disclosure exhibits heat white rust resistance, meaning that it is resistant to white rust even when placed outdoors or in a corrosive environment after high-temperature heat treatment. In conventional rust-preventive coating films, portions that have been heat-treated at high temperatures are prone to white rust when placed outdoors or in a corrosive environment. Therefore, a secondary surface treatment is required to remove white rust. The rust-preventive coating film of the present disclosure generates little white rust even when heated at high temperatures. Therefore, the secondary surface treatment can be eliminated.

[0036] A topcoat coating film may be provided on the rust-preventive coating film of the present disclosure. A multilayer coating film having the rust-preventive coating film of the present disclosure and the topcoat coating film also exhibits high rust prevention properties even when placed outdoors or in a corrosive environment after heat treatment, or when exposed to a high-temperature environment.

[0037] The reason why the above effects relating to heat discoloration resistance, heat white rust resistance and rust prevention properties of the laminated coating film are exhibited is presumably because, similar to the reason mentioned above, oxidation of the zinc-based powder (B) during heat treatment can be suppressed.

[0038] The thermal expansion coefficient of the glass powder (C) is preferably 130×10 -7 / °C or more, more preferably 140 x 10 -7 / °C or more, more preferably 145 × 10 -7 / °C or more, particularly preferably 150 x 10 -7 The thermal expansion coefficient of the glass powder (C) is preferably 220×10 -7 / °C or less, more preferably 210 × 10 -7 / °C or less, more preferably 200 x 10 -7 / °C or less, and even more preferably 195 x 10 -7 / °C or less, particularly preferably 190 x 10 -7 / °C or less. The thermal expansion coefficient of the glass powder (C) (unit: 10-7 / °C) is preferably 120 to 220, more preferably 130 to 210, even more preferably 140 to 200, still more preferably 145 to 195, and particularly preferably 150 to 190.

[0039] The thermal expansion coefficient is measured using a push rod thermal dilatometer or a thermomechanical analyzer (TMA). With the push rod thermal dilatometer, the target sample is heated at 5°C per minute in the temperature range from 23°C to above the yield point, and the average linear thermal expansion coefficient between 100 and 300°C is calculated. With the TMA, the target sample is heated at 5°C per minute in the temperature range from 23°C to above the yield point, and the average linear thermal expansion coefficient between 50 and 300°C is calculated. In this specification, the thermal expansion coefficient of the glass powder (C) is the average linear thermal expansion coefficient obtained by the first measurement method using the push rod thermal dilatometer, or, if the first measurement method is difficult to apply, the average linear thermal expansion coefficient obtained by the second measurement method using the TMA. In either measurement method, when the glass transition temperature is lower than 350°C, the upper limit temperature for calculating the average linear thermal expansion coefficient is set to a temperature 50°C lower than the glass transition temperature, and the average linear thermal expansion coefficient is calculated.

[0040] The softening point of the glass powder (C) is preferably 480°C or lower, more preferably 470°C or lower, even more preferably 460°C or lower, and still more preferably 450°C or lower. The softening point of the glass powder (C) is particularly preferably 440°C or lower, particularly preferably 430°C or lower, and most preferably 420°C or lower, and may be, for example, lower than 400°C or 398°C or lower. The softening point of the glass powder (C) is preferably 200°C or higher, more preferably 250°C or higher, even more preferably 300°C or higher, and particularly preferably 350°C or higher. By using glass powder (C) having the above thermal expansion coefficient, the obtained rust-preventive coating film can exhibit excellent rust prevention properties even when the glass powder (C) has a softening point within the above range.

[0041] The softening point of the glass powder (C) is preferably 200 to 480°C, more preferably 250 to 470°C, even more preferably 300 to 460°C, still more preferably 350 to 450°C, particularly preferably 350 to 440°C, especially preferably 350 to 430°C, and most preferably 350 to 420°C, and may be, for example, 350°C or higher but lower than 400°C, or 350°C or higher but 398°C or lower.

[0042] The softening point is measured using a push rod dilatometer or thermogravimetric differential thermal analysis (TG-DTA). In a push rod dilatometer, the softening point is the temperature at which the thermal expansion curve reaches its maximum. In TG-DTA, the target sample is heated at a rate of 10°C per minute in an air atmosphere to measure the DTA curve, and the temperature of the fourth inflection point of the DTA curve is taken as the softening point. In this specification, the softening point of the glass powder (C) is a value obtained by a first measurement method using a push rod dilatometer, or, if the first measurement method is difficult to apply, a value obtained by a second measurement method using TG-DTA.

[0043] Examples of components constituting the glass powder (C) include SiO, BO, AlO, ZnO, BaO, MgO, CaO, SrO, BiO, LiO, NaO, KO, PbO, PO, InO, SnO, CuO, AgO, VO, and TeO. PbO can also be used as a compound constituting the glass powder (C), but from the viewpoint of low environmental pollution, it is preferable that the glass powder (C) does not contain PbO.

[0044] The thermal expansion coefficient and softening point of the glass powder (C) can be appropriately adjusted, for example, by the types, combinations, and content ratios of the components constituting the glass powder (C). The glass powder (C) can be obtained, for example, by heating and melting the compounds constituting the glass at about 1000 to 1100°C for a predetermined time, cooling the mixture, and then granulating it into powder using a grinding device.

[0045] The median diameter (D50) of the glass powder (C) is preferably 1 to 30 μm, more preferably 1.5 to 25 μm, and even more preferably 2 to 20 μm. The median diameter is calculated from a volume-based particle size distribution obtained using a laser scattering diffraction particle size distribution analyzer, for example, "SALD 2200" (trade name; manufactured by Shimadzu Corporation).

[0046] The content of the glass powder (C) in the solid content of the composition of the present disclosure or in the rust-preventive coating film formed from the composition is preferably 0.01 to 20 mass%, more preferably 0.1 to 15 mass%, and even more preferably 0.2 to 10 mass%. Such a composition and rust-preventive coating film tend to be able to more effectively exhibit the above-mentioned effects.

[0047] In the composition of the present disclosure or the rust-preventive coating film formed from the composition, the ratio of the content of the glass powder (C) to the content of the zinc-based powder (B) ((C) / (B)) is preferably 0.005 to 0.10, more preferably 0.010 to 0.09, and even more preferably 0.013 to 0.08, by mass. Such a composition and rust-preventive coating film tend to be able to more effectively exhibit the above-mentioned effects.

[0048] <Pigment Component> The composition of the present disclosure may further contain, for example, a pigment component other than the zinc-based powder (B) and the glass powder (C). Examples of the pigment component include a metal-based powder other than the zinc-based powder (B), an anti-rust pigment other than the zinc-based powder (B), an inorganic powder other than the zinc-based powder (B), molybdenum, a molybdenum compound, an extender pigment, and a coloring pigment. The pigment component may be one type or two or more types.

[0049] The metal-based powders other than the zinc-based powder (B) are electrically conductive and have the effect of facilitating the movement of iron ions or zinc ions, thereby enhancing the rust-preventing effect of the coating film. Examples of the metal-based powder include metal powders and metal alloy powders. Examples of the metal-based powder include Fe—Si powder, Fe—Mn powder, Fe—Cr powder, magnetic iron powder, and iron phosphide powder.

[0050] From the viewpoint of further improving the rust prevention properties of the coating film, the composition of the present disclosure may further contain an anti-rust pigment other than the zinc-based powder (B). Examples of the anti-rust pigment include zinc phosphate compounds, calcium phosphate compounds, aluminum phosphate compounds, magnesium phosphate compounds, zinc phosphite compounds, calcium phosphite compounds, aluminum phosphite compounds, strontium phosphite compounds, aluminum tripolyphosphate compounds, zinc cyanamide compounds, borate compounds, nitro compounds, and composite oxides.

[0051] Examples of inorganic powders other than the zinc-based powder (B) include zinc compound powders (excluding zinc phosphate-based compounds, zinc phosphite-based compounds, and zinc cyanamide-based compounds), and inorganic compound powders that generate gas upon thermal decomposition.

[0052] The zinc compound powder is an ionized zinc-based powder (B) (Zn 2+ It is believed that zinc compounds have the effect of adjusting the activity of oxidation reactions, such as the degree of oxidation reaction (the formation of zinc oxide). The composition containing zinc compound powder has even better rust prevention properties. Examples of zinc compound powder include zinc oxide, zinc chloride, zinc sulfide, and zinc sulfate.

[0053] The composition of the present disclosure contains a zinc compound powder, and the content of the zinc compound powder in the solid content of the composition or in the rust-preventive coating film formed from the composition is preferably 0.1 to 20 mass%, more preferably 0.2 to 15 mass%, and even more preferably 0.3 to 10 mass%.

[0054] The inorganic compound powder that generates gas upon thermal decomposition is a powder of an inorganic compound that generates gas (e.g., CO2, F2) upon thermal decomposition (e.g., thermal decomposition at 500 to 1,500°C). By using this inorganic compound powder, bubbles generated from gas generated from organic components contained in the binder (A) and the like in the molten pool during welding of coated products can be removed from the molten pool together with gas derived from the inorganic compound powder. Examples of the inorganic compound powder include calcium fluoride, calcium carbonate, magnesium carbonate, and strontium carbonate.

[0055] The composition of the present disclosure contains an inorganic compound powder that generates a gas upon thermal decomposition, and the content of the inorganic compound powder that generates a gas upon thermal decomposition is preferably 0.1 to 8 mass %, more preferably 0.2 to 4 mass %, based on the solid content of the composition or the rust-preventive coating film formed from the composition.

[0056] The composition of the present disclosure may further contain at least one component selected from the group consisting of molybdenum (metallic molybdenum) and molybdenum compounds (hereinafter also referred to as the "molybdenum component"). The molybdenum component acts as an antioxidant (so-called white rust inhibitor) for the zinc-based powder (B) and reduces the occurrence of white rust in the coating film.

[0057] Examples of molybdenum compounds include molybdenum oxides such as molybdenum trioxide, molybdenum sulfide, molybdenum halides, metal salts of molybdic acid such as molybdic acid, ammonium molybdate, phosphomolybdic acid, silicomolybdic acid, and zinc molybdate, alkali metal salts of molybdic acid, alkali metal salts of phosphomolybdic acid, alkali metal salts of silicomolybdic acid, alkaline earth metal salts of molybdic acid such as calcium molybdate, alkaline earth metal salts of phosphomolybdic acid, alkaline earth metal salts of silicomolybdic acid, manganese salts of molybdic acid, manganese salts of phosphomolybdic acid, manganese salts of silicomolybdic acid, basic nitrogen-containing compound salts of molybdic acid, basic nitrogen-containing compound salts of phosphomolybdic acid, and basic nitrogen-containing compound salts of silicomolybdic acid.

[0058] The composition of the present disclosure will be described below when it contains a molybdenum component. The content of the molybdenum component is preferably 0.05 to 5.0 parts by mass, more preferably 0.3 to 3.0 parts by mass, and even more preferably 0.5 to 2.0 parts by mass, per 100 parts by mass of the zinc-based powder (B). Such a composition can sufficiently suppress oxidation of the zinc-based powder (B) and form a coating film with excellent rust prevention properties.

[0059] The composition of the present disclosure may further contain an extender pigment. The extender pigment is not particularly limited as long as it is an inorganic pigment used as a component of general paints, and examples thereof include potassium feldspar, soda feldspar, kaolin, mica, silica, talc, barium sulfate, aluminum oxide, zirconium silicate, wollastonite, and diatomaceous earth. The extender pigment may be an inorganic pigment that generates gas upon thermal decomposition.

[0060] The composition of the present disclosure containing a body pigment will now be described. The content of the body pigment in the solid content of the composition or in the rust-preventive coating film formed from the composition is preferably 0.1 to 60 mass %, more preferably 1 to 50 mass %, and even more preferably 5 to 40 mass %.

[0061] The composition of the present disclosure may further contain a color pigment. The color pigment can, for example, impart a desired hue to the coating film. Examples of color pigments include inorganic pigments such as titanium oxide, red iron oxide, iron oxide, iron hydroxide, carbon black, copper chromium, ultramarine, iron oxide-manganese oxide, iron oxide-chromium oxide, iron oxide-cobalt oxide-chromium oxide, copper oxide-magnesium oxide, manganese oxide-bismuth oxide, and manganese oxide-yttrium oxide; and organic pigments such as phthalocyanine green and phthalocyanine blue.

[0062] The composition of the present disclosure contains a color pigment, and the content of the color pigment is preferably 0.1 to 20 mass %, more preferably 0.2 to 15 mass %, and even more preferably 0.3 to 10 mass %, based on the solid content of the composition or the rust-preventive coating film formed from the composition.

[0063] <Additives> The composition of the present disclosure may further contain additives. Additives are materials used to improve or maintain the performance of a paint or coating film. Examples of additives include anti-settling agents, thickeners, anti-sagging agents, drying agents, flow control agents, anti-foaming agents, dispersants, color separation inhibitors, anti-skinning agents, plasticizers, and ultraviolet absorbers. The additives may be one type or two or more types.

[0064] Examples of anti-settling agents include organic bentonite-based anti-settling agents, polyethylene oxide-based anti-settling agents, fumed silica-based anti-settling agents, and amide-based anti-settling agents. Anti-settling agents may be used alone or in combination. Cases in which the composition of the present disclosure contains an anti-settling agent will be described. The content of the anti-settling agent in the solid content of the composition or in the rust-preventive coating film formed from the composition is preferably 0.5 to 8 mass%, more preferably 1 to 6 mass%.

[0065] Examples of thickeners include known thickeners such as tricalcium phosphate. One type of thickener may be used, or two or more types may be used. A case where the composition of the present disclosure contains a thickener will be described. The content of the thickener in the solid content of the composition or in the rust-preventive coating film formed from the composition is preferably 0.5 to 8 mass%, more preferably 1 to 6 mass%.

[0066] The composition of the present disclosure may further contain an organic solvent. Such a composition has excellent dispersibility of each component, such as the zinc-based powder (B), and also has good compatibility with substrates during application, allowing the formation of a coating film that has excellent adhesion to the substrate.

[0067] Examples of the organic solvent include organic solvents that are commonly used in the field of coatings, such as alcohol-based solvents, ester-based solvents, ketone-based solvents, aromatic solvents, and glycol-based solvents.

[0068] Examples of alcohol-based solvents include methanol, ethanol, propanol, and butanol. Examples of ester-based solvents include ethyl acetate and butyl acetate. Examples of ketone-based solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanenone. Examples of aromatic solvents include benzene, xylene, and toluene. Examples of glycol-based solvents include propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate. One type of organic solvent may be used, or two or more types may be used.

[0069] The composition of the present disclosure preferably contains an organic solvent in an amount of 20 to 90% by mass, more preferably 25 to 85% by mass, and even more preferably 30 to 80% by mass.

[0070] <Form of Anti-Rust Coating Composition> The composition of the present disclosure may be, for example, a sachet-type composition having a first agent containing a binder (A) and a second agent containing a zinc-based powder (B) and a glass powder (C), a sachet-type composition having a first agent containing a binder (A) and a glass powder (C) and a second agent containing a zinc-based powder (B), or a sachet-type composition having a first agent containing a binder (A), a second agent containing a zinc-based powder (B), and a third agent containing a glass powder (C). The sachet-type composition may further contain another agent containing at least one component selected from the group consisting of the above-mentioned components.

[0071] Each agent, such as the first agent, the second agent, the third agent, and other agents, is usually preserved, stored, or transported in a separate container. At the time of use (e.g., immediately before painting), the first agent, the second agent, and other agents used as needed, or the first agent, the second agent, the third agent, and other agents used as needed, are mixed together to form a mixture.

[0072] The composition of the present disclosure may be, for example, a two-part composition consisting of a liquid first part and a powder, paste, or liquid second part. The composition of the present disclosure may be, for example, a three-part composition consisting of a liquid first part, a powder, paste, or liquid second part, and a powder, paste, or liquid third part.

[0073] The first agent contains a binder (A) and preferably further contains an organic solvent. The first agent may further contain a glass powder (C). The first agent may further contain at least one selected from the group consisting of the pigment components and additives described above. The first agent may be in a liquid form or a paste form, and is preferably in a liquid form.

[0074] The first agent may contain a siloxane binder as the binder (A). The first agent may be prepared, for example, by mixing a siloxane binder with an organic solvent. The first agent may be prepared, for example, by adding hydrochloric acid or the like to a mixed solution of at least one selected from the group consisting of alkoxysilanes and their low condensates with an organic solvent, and stirring the mixture to produce a partial hydrolysis condensate.

[0075] The second agent contains a zinc-based powder (B) and preferably further contains an organic solvent. The second agent may further contain a glass powder (C). The second agent may further contain at least one selected from the group consisting of the pigment components and additives described above. The second agent may be in liquid, paste, or powder form, preferably paste or powder form, and more preferably paste form.

[0076] The third agent contains glass powder (C) and preferably further contains an organic solvent. The third agent may further contain at least one selected from the group consisting of the pigment components and additives described above. The third agent may be in the form of a liquid, a paste, or a powder, preferably in the form of a paste or powder, and more preferably in the form of a paste.

[0077] The content ratio of each component contained in the first agent can be appropriately set so that the content ratio of each component in the coating composition or its solid content when the coating composition is prepared by mixing the first agent, second agent, etc., falls within the above-mentioned range. The same applies to the content ratio of each component contained in the second agent and the content ratio of each component contained in the third agent.

[0078] For example, when the first agent is a mixture, it can be prepared by mixing the respective components to be blended. For example, when the second agent is a mixture, it can be prepared by mixing the respective components to be blended. For example, when the third agent is a mixture, it can be prepared by mixing the respective components to be blended. When mixing, each component may be added at once or in multiple portions.

[0079] <Preparation of Anti-Rust Coating Composition> The composition of the present disclosure can be prepared, for example, by mixing the binder (A), the zinc-based powder (B), the glass powder (C), and, if necessary, other components, such as the pigment component, additives, and organic solvent, as described above.

[0080] In the case of the above-mentioned divided-package composition, the first agent, the second agent, and optionally additional agents are mixed before coating the substrate to obtain a coating composition. The blending ratio of each agent can be appropriately set so that the content of each component after mixing falls within the above-mentioned range. The obtained coating composition is used to coat the substrate.

[0081] The mixing can be performed using conventionally known devices such as mixers, dispersers, and stirrers. Examples of such devices include dispersers, mixing / dispersion mills, mortar mixers, rolls, paint shakers, and homogenizers. Mixing can be performed while heating or cooling, depending on the season or environment.

[0082] The composition of the present disclosure may be diluted before use depending on the coating method, etc. All descriptions in this specification, except for those related to such dilution, are descriptions of the composition before dilution.

[0083] [Anti-rust coating film and coated article] The anti-rust coating film of the present disclosure is formed from the composition of the present disclosure. The coated article of the present disclosure has a substrate and the anti-rust coating film of the present disclosure provided on the substrate. For example, the anti-rust coating film and coated article of the present disclosure can be obtained by applying the composition of the present disclosure to the substrate and curing it.

[0084] The anti-rust coating film of the present disclosure contained in the coated article may be one layer or two or more layers. The average film thickness of the anti-rust coating film of the present disclosure is preferably 1 to 100 μm, more preferably 3 to 80 μm, even more preferably 5 to 60 μm, and particularly preferably 7 to 40 μm. The average film thickness is measured using an electromagnetic film thickness meter. The anti-rust coating film having the above average film thickness may be formed by one coating, or may be formed by two or more coatings.

[0085] Examples of materials for the substrate include iron and steel (e.g., iron, steel, ferroalloy, carbon steel, mild steel, alloy steel, stainless steel), non-ferrous metals (e.g., zinc, aluminum, copper, brass, zinc plating, zinc thermal spraying), and also plastics (e.g., polypropylene, polyamide, polycarbonate, polyurethane, polyester, polystyrene, vinyl chloride resin), ceramics, glass, and concrete. Among these, iron and steel is preferred.

[0086] Specific examples of the substrate include ships (e.g., ship decks, superstructures or outer hulls, engines, chimneys, etc.), marine structures (e.g., marine buoys, undersea pipelines), structures (e.g., plants, tanks, containers), bridges, and outdoor equipment (e.g., guard fences, industrial machinery). Steel structures are preferred as the substrate.

[0087] The substrate may be a substrate that has been subjected to a pretreatment such as a cleaning treatment to remove rust, dirt, or a coating film (old coating film) adhering to the substrate, or a blast treatment. If necessary, the substrate may be subjected to a blast treatment under conditions corresponding to a rust removal degree Sa2 1 / 2 or more in ISO 8501-1.

[0088] The coated article of the present disclosure may have an additional coating film (hereinafter also referred to as a "topcoat coating film") on the rust-preventive coating film of the present disclosure. That is, the coated article of the present disclosure may have a substrate, the rust-preventive coating film of the present disclosure, and a topcoat coating film, in this order. Examples of topcoat coating films include silicone resin-based, epoxy resin-based, epoxy ester resin-based, polyurethane resin-based, fluororesin-based, (meth)acrylic resin-based, vinyl resin-based, chlorinated rubber-based, and inorganic zinc-based coating films. The average film thickness of the topcoat coating film is not particularly limited, but is preferably 1 to 100 μm, more preferably 3 to 90 μm, and even more preferably 5 to 80 μm.

[0089] The coated article of the present disclosure can be produced, for example, by a method having the steps of applying the composition of the present disclosure to a substrate and curing it to form an anti-rust coating film. Specifically, the coated article of the present disclosure can be produced by a method having the steps of applying the composition of the present disclosure to a substrate to form an uncured coating film, and curing the coating film to form an anti-rust coating film.

[0090] First, the composition of the present disclosure (in the case of a packaged composition, a composition obtained by mixing the first and second agents) is applied to a substrate to form an uncured coating film. Examples of methods for applying the composition include air spray coating, airless spray coating, roll coater coating, brush coating, and dip coating. Generally, when coating substrates at shipyards or steelworks, a line coater may be used. The line coater controls the film thickness by adjusting coating conditions such as the line speed, the coating pressure of the air sprayer or airless sprayer installed inside the coater, and the size (diameter) of the spray tip.

[0091] The composition or coating is then cured. The curing temperature (drying temperature) is preferably 5 to 40°C, more preferably 10 to 30°C, and may be, for example, ambient temperature. The curing time (drying time) is usually 3 minutes to 100 hours, preferably 5 minutes to 60 hours.

[0092] The method for curing the composition or coating film is not particularly limited, and any conventionally known curing method may be used. For example, a composition containing a siloxane binder as the binder (A) will be described. When the composition applied to a substrate is left in air (with heating as necessary), the organic solvent evaporates, and the siloxane binder undergoes a hydrolysis and condensation reaction with the water in the composition or moisture (humidity) in the air, thereby curing.

[0093] As described above, the coated articles of the present disclosure are excellent in rust prevention, heat discoloration resistance, and heat white rust resistance even when subjected to heat treatment (for example, heat treatment at high temperatures such as 400 to 900°C). For example, anti-rust paints used in steel processing processes, etc., are required to protect steel from rust without interfering with fusing, welding, and other processes in the construction process, and also to minimize changes in hue due to oxidation of zinc during heat treatment. For this reason, the compositions of the present disclosure are suitable as anti-rust paints used in steel processing processes, etc.

[0094] [Examples] The present disclosure relates to the following [1] to

[12] , for example: [1] A binder (A), a zinc-based powder (B), and a 120×10-7 [2] The rust-preventive coating composition according to [1], wherein the glass powder (C) has a softening point of 480°C or less. [3] The thermal expansion coefficient of the glass powder (C) is 120 x 10 -7 / ℃~220×10 -7 / °C. [4] The anticorrosive coating composition according to any one of [1] to [3], wherein the binder (A) is a siloxane-based binder. [5] The anticorrosive coating composition according to [4], wherein the siloxane-based binder is a condensate of at least one compound selected from the group consisting of tetraalkoxysilanes and alkyltrialkoxysilanes. [6] The anticorrosive coating composition according to [4] or [5], wherein the siloxane-based binder has a weight-average molecular weight (Mw) of 1,300 to 10,000. [7] The anticorrosive coating composition according to any one of [1] to [6], wherein, based on the solid content of the anticorrosive coating composition, the content of the binder (A) is 1 to 30 mass%, the content of the zinc-based powder (B) is 10 to 90 mass%, and the content of the glass powder (C) is 0.01 to 20 mass%. [8] The anticorrosive coating composition according to any one of [1] to [7], wherein the ratio of the content of the glass powder (C) to the content of the zinc-based powder (B) ((C) / (B)) is 0.005 to 0.10 by mass. [9] The anticorrosive coating composition according to any one of [1] to [8], wherein the anticorrosive coating composition is a sachet-type composition having a first part containing the binder (A) and a second part containing the zinc-based powder (B) and the glass powder (C), a sachet-type composition having a first part containing the binder (A) and the glass powder (C) and a second part containing the zinc-based powder (B), or a sachet-type composition having a first part containing the binder (A), a second part containing the zinc-based powder (B), and a third part containing the glass powder (C).

[10] A anticorrosive coating film formed from the anticorrosive coating composition according to any one of [1] to [9].

[11] A coated article having a substrate and the rust-preventive coating film according to

[10] above provided on the substrate.

[12] A method for producing a coated article, comprising the steps of applying the rust-preventive coating composition according to any one of [1] to [9] above to a substrate and curing the composition to form the rust-preventive coating film.

[0095] The composition of the present disclosure will be described in more detail below with reference to examples, but the composition of the present disclosure is not limited to these examples.

[0096] [Raw Materials] Raw materials used in the examples and comparative examples are listed below. Alkyl silicate Ethyl silicate 40, manufactured by Colcoat Co., Ltd. Anti-settling agent AEROESIL 200, manufactured by Nippon Aerosil Co., Ltd. Thickener Tricalcium phosphate, manufactured by Taihei Chemical Industry Co., Ltd. Zinc oxide Zinc oxide 3 types, manufactured by Hakusui Tech Co., Ltd. Potassium feldspar Feldspar PG-K10, manufactured by Sibelco Black pigment Dipyroxide Black #9510, manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd. Zirconium silicate A-PAX 45M, manufactured by Kinseimatec Co., Ltd. Zinc powder Larvik Superfine 25, manufactured by EverZinc Particle size (D50): 4.2 μm Glass powder CY5401, manufactured by Takara Standard Co., Ltd. Softening point: 641 ° C, thermal expansion coefficient: 67 × 10 -7 / °C Composition: SiO2-B2O3, particle size (D50): 10 μm Glass powder TMX-302F, manufactured by TOMATEC Co., Ltd. Softening point: 490°C, thermal expansion coefficient: 88 × 10 -7 / °C Composition: ZnO-B2O3-Bi2O3, particle size (D50): 2 μm Glass powder TMX-501F, manufactured by TOMATEC Co., Ltd. Softening point: 545°C, thermal expansion coefficient: 79 × 10 -7 / °C Composition: Bi2O3-ZnO-B2O3, particle size (D50): 2 μm Glass powder 01-4102P, manufactured by TOMATEC Co., Ltd. Softening point: 384°C, thermal expansion coefficient: 166 × 10 -7 / °C Composition: P-Al-B-Na-K-F, particle size (D50): 9 μm Glass powder VY0047M2, manufactured by Takara Standard Co., Ltd. Softening point: 420°C, thermal expansion coefficient: 177 × 10 -7 / °C Composition: PO-AlO-RO, particle size (D50): 9 μm Glass powder VY0144, manufactured by Takara Standard Co., Ltd. Softening point: 404°C, thermal expansion coefficient: 163 × 10 -7 / °C Composition: PO-AlO-RO, particle size (D50): 10 μm (RO represents alkali metal oxides such as LiO, NaO, and KO.)

[0097] Preparation Example 1 55 g of ethyl silicate 40, 25 g of ethanol, 5 g of deionized water, and 0.03 g of 35% hydrochloric acid were placed in a vessel. The mixture in the vessel was stirred at 50° C. for 3 hours, and then 15 g of isopropyl alcohol was added to the mixture to obtain a solution of an alkyl silicate condensate (Mw: 1,700) (hereinafter also referred to as “Solution A”).

[0098] Preparation Example 2: 31.5 g of ethyl silicate 40, 13.4 g of isobutyl alcohol, 5 g of deionized water, and 0.05 g of 35% hydrochloric acid were placed in a vessel. The mixture in the vessel was stirred at 50° C. for 3 hours, and then 50 g of isopropyl alcohol was added to the mixture to obtain a solution of an alkyl silicate condensate (Mw: 3,000) (hereinafter also referred to as “Solution B”).

[0099] [Preparation Example 3. Paste] The raw materials (except zinc powder) shown as pastes in Table 1 were each placed in a polyethylene container, glass beads were added, and the mixture was shaken for about 2 hours using a paint shaker. Next, zinc powder was added to the polyethylene container, and the mixture was shaken for 10 minutes using a paint shaker. Next, the glass beads were removed using a 120-mesh filter, and a paste was obtained.

[0100] [Examples 1 to 7 and Comparative Examples 1 to 4] In the examples and comparative examples shown in Table 1, coating compositions were obtained by mixing alkyl silicate condensate solution A and a pasting agent in the formulation shown in Table 1. In the examples and comparative examples shown in Table 2, alkyl silicate condensate solution B, zinc powder, and glass powder were mixed in the formulation shown in Table 2, and the resulting mixture was stirred for about 1 minute to obtain coating compositions.

[0101] [Evaluation Test] <Preparation of Test Plate> A sandblasted plate (JIS G3101:2024, SS400, dimensions: 150 mm x 70 mm x 2.3 mm) was prepared. The blasted surface of the sandblasted plate was painted with an air spray using the coating composition of the Example or Comparative Example. Next, the painted sandblasted plate was aged for one week in a constant temperature room at a temperature of 23°C and a relative humidity of 50% in accordance with the standard of JIS K5600-1-6:1999. In this way, test plates were obtained that had a sandblasted plate and an anti-rust coating film having the average film thickness shown in each table. The average film thickness was measured using an electromagnetic film thickness meter "Deltascope FMP-30" (Fisher Instruments).

[0102] <(1) Rust Prevention Test: Salt Spray Test (Single Film)> The test plate was heated in a heating furnace at 800°C for 3 minutes, then removed from the furnace and cooled to room temperature. The test plate was then placed in a salt spray tester specified in JIS K5600-7-1:1999, item "4. Apparatus." The temperature inside the tester was set to 35°C ± 2°C, and the sodium chloride concentration of the salt water was 5%. After continuously spraying salt water onto the rust-preventive coating surface of the test plate for 720 hours, the state of red rust on the test plate was confirmed. The ratio (rust rate) (%) of the area where red rust had developed to the evaluated area of ​​the test plate was determined, and the state of red rust development was evaluated on a scale of 0 to 10 based on the following evaluation criteria in accordance with ASTM D610.

[0103] <(2) Heat Discoloration Resistance Test> Two test plates were prepared for each of the examples and comparative examples. One test plate was heated in a heating furnace at 800°C for 3 minutes, then removed from the furnace and cooled to room temperature. The other test plate was not subjected to this heat treatment. The color difference (ΔE represented by the following formula) of the heat-treated test plate relative to the unheated test plate was measured using a spectrophotometer (SPECTROPHOTOMETER CM-3700, manufactured by Konica Minolta, Inc.) under conditions of a C illuminant D65 and a viewing angle of 10°, and then calculated. The smaller the color difference, the better the heat discoloration resistance was judged to be. ΔE = {(L * 1-L * 0) 2 + (a *1-a * 0) 2 +(b * 1-b * 0) 2} 1 / 2 L * 1. a * 1, b * 1 is the L of the test plate after heat treatment * , a * , b * and L * 0, a * 0, b * 0 is the L of the test plate that has not been heat treated * , a * , b * respectively.

[0104] <(3) Heat Resistance Test> The test plate was heated in a heating furnace at 800°C for 3 minutes, then removed from the furnace and cooled to room temperature. Next, water was sprayed thoroughly onto the surface of the rust-preventive coating film on the test plate using an atomizer until it was completely wet. After the surface of the rust-preventive coating film on the test plate had dried, it was sprayed again in the same manner. Spraying was performed three times. After spraying, the test plate was left for approximately 16 hours. The state of red rust and the state of white rust on the test plate were checked. The state of red rust was evaluated on a scale of 0 to 10 based on the following evaluation criteria in accordance with ASTM D610, and the state of white rust was evaluated on a scale of 0 to 10 based on the following evaluation criteria.

[0105] <(4) Rust prevention test after topcoat application> A silicone topcoat paint (Silicon Tainetsu Black (K), manufactured by Chugoku Toryo Co., Ltd.) was applied to the surface of the rust-preventive coating film of the above test plate and heated at 200°C for 2 hours to form a topcoat coating film with an average film thickness of 20 μm. The test plate was then heated at 400°C for 2 hours. Salt water was continuously sprayed onto the topcoat coating surface of the test plate under the same conditions as in (1) above for 50 hours, and the state of red rust and white rust on the test plate was then observed. The state of red rust was evaluated on a scale of 0 to 10 based on the following evaluation criteria in accordance with ASTM D610, and the state of white rust was evaluated on a scale of 0 to 10 based on the following evaluation criteria.

[0106] The evaluation criteria for the state of red rust are as follows: 10: No rust, or rust ratio 0.01% or less 9: Rust ratio greater than 0.01% and less than 0.03% 8: Rust ratio greater than 0.03% and less than 0.1% 7: Rust ratio greater than 0.1% and less than 0.3% 6: Rust ratio greater than 0.3% and less than 1% 5: Rust ratio greater than 1% and less than 3% 4: Rust ratio greater than 3% and less than 10% 3: Rust ratio greater than 10% and less than 16% 2: Rust ratio greater than 16% and less than 33% 1: Rust ratio greater than 33% and less than 50% 0: Rust area greater than 50% and less than 100%

[0107] The evaluation criteria for the occurrence of white rust are as follows: Although the evaluation is based on even points, odd points may be used if the state of white rust on the test plate is halfway between the even points. 10: No white rust is observed. 8: Slight white rust is observed. 6: White rust is partially observed. 4: White rust is observed over a wide area. 2: White rust is observed over a significantly wide area. 0: White rust is observed over the entire surface.

[0108]

[0109]

Claims

1. Binder (A), zinc-based powder (B), and 120 x 10 -7 A rust-preventive coating composition comprising: a glass powder (C) having a thermal expansion coefficient of 1 / °C or more; and 2. The anticorrosive coating composition according to claim 1, wherein the glass powder (C) has a softening point of 480°C or less.

3. The thermal expansion coefficient of the glass powder (C) is 120×10 -7 / ℃~220×10 -7 The anticorrosive coating composition according to claim 1, wherein the temperature is 100°C.

4. The anticorrosive coating composition according to claim 1, wherein the binder (A) is a siloxane-based binder.

5. The anticorrosive coating composition according to claim 4, wherein the siloxane binder is a condensate of at least one compound selected from the group consisting of tetraalkoxysilanes and alkyltrialkoxysilanes.

6. The anticorrosive coating composition according to claim 4, wherein the weight average molecular weight (Mw) of the siloxane binder is 1,300 to 10,000.

7. The anti-rust coating composition according to claim 1, wherein, in the solid content of said anti-rust coating composition, the content of said binder (A) is 1 to 30 mass %, the content of said zinc-based powder (B) is 10 to 90 mass %, and the content of said glass powder (C) is 0.01 to 20 mass %.

8. The rust-preventive coating composition according to claim 1, wherein the ratio ((C) / (B)) of the content of said glass powder (C) to the content of said zinc-based powder (B) is 0.005 to 0.10 by mass.

9. The anti-corrosion coating composition according to claim 1, which is a sachet-type composition having a first agent containing the binder (A) and a second agent containing the zinc-based powder (B) and the glass powder (C); a sachet-type composition having a first agent containing the binder (A) and the glass powder (C) and a second agent containing the zinc-based powder (B); or a sachet-type composition having a first agent containing the binder (A), a second agent containing the zinc-based powder (B), and a third agent containing the glass powder (C).

10. An anti-rust coating film formed from the anti-rust coating composition according to any one of claims 1 to 9.

11. A coated article comprising: a substrate; and the anticorrosive coating film according to claim 10 provided on the substrate.

12. A method for producing a coated product, comprising the steps of applying the anti-rust coating composition according to any one of claims 1 to 9 to a substrate and curing it to form an anti-rust coating film.

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