JP2020026457A - Coating material composition, corrosion prevention method and coated body - Google Patents

Abstract

To provide a coating material composition that has excellent anticorrosion property, does not generate a hydrogen gas within a coating film even when applying a coating having an excessive film thickness under a high humidity condition and has a wide application scope of in-situ coating.SOLUTION: The coating material composition includes (A) a metal less noble than iron, (B) a binder resin, (C) an adhesion promoter and (D) water. The binder resin (B) includes at least one kind of resin selected from an acrylic resin, an epoxy resin and an epoxyester resin and the adhesion promotor (C) is at least one kind of compound selected from a phosphoric acid ester compound and a sulfonic acid ester compound.SELECTED DRAWING: None

Description

  The present invention relates to a coating composition, and an anticorrosion method and a coated body using the coating composition, in particular, while having excellent anticorrosion properties, even when coated in an excessively thick film under a high humidity environment, The present invention relates to a coating composition that can suppress generation of hydrogen gas in a coating film during a drying process and has a wide range of application in a field.

  2. Description of the Related Art Conventionally, so-called zinc-rich paint containing a large amount of zinc powder has been widely used for coating various onshore steel structures and marine steel structures such as bridges, plants and tanks for corrosion protection. The zinc-rich paint is generally an inorganic zinc-rich paint using an alkyl silicate as a vehicle and an organic zinc-rich paint using an epoxy resin as a vehicle.These are mainly solvent-based zinc-rich paints using an organic solvent. there were. However, in recent years, there has been a strong demand for conversion to water-based zinc-rich paint in which water or water is used in combination with a small amount of an organic solvent from the viewpoint of preventing air pollution and saving resources.

  Japanese Patent Application Laid-Open No. 2013-199546 (Patent Document 1) describes an aqueous anticorrosion coating composition containing an aqueous epoxy resin, an amine resin, and zinc powder having a specific bulk specific gravity. It describes that it is possible to provide a coating film that is excellent in coating workability and also excellent in corrosion resistance and impact resistance.

JP 2013-199546 A

  The coating composition described in Patent Literature 1 can exhibit excellent performance for coating a general part of a steel structure. Since hydrogen gas is generated by the reaction at the end of the coating process, the coating film is dried at places where the film thickness becomes excessive at seams and steps, etc. After that, it became clear that hydrogen gas was generated in the coating film. The generated hydrogen gas is released to the atmosphere in the state of the paint before painting, but if it is generated in the coating after the surface is dried, it cannot escape to the atmosphere, resulting in coating defects. There is a risk of being connected.

  As a method of suppressing the generation of hydrogen in zinc-rich paint, a zinc powder-containing slurry obtained by mixing a zinc powder and an alkali silicate solution having a reduced degree of polymerization by hydrolysis is used to coat silica on the surface of the zinc powder. A method of forming a dense film of, preventing the contact between zinc and water to obtain high water stability of zinc powder (Japanese Patent Application Laid-Open No. 2004-2637), using a silane coupling agent having a mercapto group, A method in which a mercapto group contained in a molecule of a silane coupling agent selectively forms a chemical bond with zinc powder to provide a protective effect of suppressing the reaction of zinc powder (JP-A-2004-35828), Method of suppressing generation of hydrogen bubbles by reaction with aqueous binder solution by adding a silane compound having a hydrophobic group to zinc powder particles 94490, JP 2005-238001 JP) have been proposed.

  However, since these conventional methods protect the zinc dust surface in water, the generation of hydrogen gas during the drying process of the coating film is not considered, and the coating is performed with an excessive thickness in an environment of high humidity. Hydrogen gas generation that occurs in the event of a spill is not sufficiently prevented, and the surface of zinc is excessively coated, so that the sacrificial anticorrosion function of zinc is reduced, and both anticorrosion properties and suppression of hydrogen gas generation are achieved. I couldn't do it.

  Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, to have excellent anticorrosion properties, and to generate hydrogen gas in a coating film even when applied in an excessive thickness under high humidity conditions. It is an object of the present invention to provide a coating composition having a wide range of coating applications in the field without the above. Another object of the present invention is to provide an anticorrosion method and a coated body using such a coating composition.

  The present inventors have conducted intensive studies to achieve the above object, and as a result, added an adhesion promoter that is a phosphoric acid ester or a sulfonic acid ester to an anticorrosion paint composition containing a metal that is less basic than iron, such as zinc. By doing so, even under high-humidity, over-thickness coating conditions, there is no occurrence of coating defects due to hydrogen gas generation, and a sacrificial anticorrosion coating composition that exhibits a wide range of on-site coating applications Have been found, and the present invention has been completed.

  That is, the coating composition of the present invention is a coating composition containing (A) a metal lower than iron, (B) a binder resin, (C) an adhesion promoter, and (D) water; The binder resin includes at least one resin selected from an acrylic resin, an epoxy resin, and an epoxy ester resin, and the adhesion promoter (C) is at least one compound selected from phosphate esters and sulfonic acid esters. There is a feature.

  In a preferred example of the coating composition of the present invention, (C) the adhesion promoter is a compound having at least one group selected from an alkyl group and an allyl group.

  In another preferred embodiment of the coating composition of the present invention, (C) the adhesion promoter is a free acid of a phosphoric ester.

  In another preferred embodiment of the coating composition of the present invention, the molecular weight of (C) the adhesion promoter is in the range of 300 to 3000.

  In another preferred embodiment of the coating composition of the present invention, (A) the metal which is more base than iron is zinc.

  In another preferred embodiment of the coating composition of the present invention, the weight ratio of the metal lower than (A) iron to the total weight of (B) the binder resin and (C) the adhesion promoter is (A) / [(B ) + (C)] = 3 to 15.

  In another preferred embodiment of the coating composition of the present invention, the content of (B) the binder resin in the coating is in the range of 5 to 30% by weight, and the content of (C) the adhesion promoter in the coating. Is in the range of 0.1 to 10% by weight.

  In another preferred embodiment of the coating composition of the present invention, the weight ratio of the adhesion promoter (C) to the weight of the metal (A) lower than iron is (C) / (A) = 0.001 to 0.1. 2 is within the range.

  In another preferred embodiment of the coating composition of the present invention, the binder resin (B) is an epoxy resin, and further contains an amine compound as a curing agent.

  The anticorrosion method of the present invention is characterized by including a step of coating a metal-based substrate with the coating composition to form a coating film.

  In a preferable example of the anticorrosion method of the present invention, the coating condition of the metal base material with the coating composition is such that the coating thickness is 30 to 500 μm in a coating environment of a temperature of 5 ° C. to 40 ° C. and a relative humidity of 50 to 95%. These are the coating conditions for forming the coating film.

  In another preferred embodiment of the anticorrosion method of the present invention, the coating condition of the metal-based substrate with the coating composition is a dry film thickness of 250 in a coating environment of a temperature of 20 to 40 ° C. and a relative humidity of 60 to 95%. These are the coating conditions for forming a coating film having a thickness of 500 μm.

  Another preferred embodiment of the anticorrosion method of the present invention includes a step of applying the coating film with an aqueous paint different from the coating composition to form a further coating film.

  Further, the coated body of the present invention includes a metal-based substrate, and a coating film formed on the metal-based substrate, wherein the coating film is formed from the coating composition. I do.

  In a preferred embodiment of the coated body according to the present invention, the coated body further includes a further coating film formed on the coating film, wherein the further coating film is formed from an aqueous coating different from the coating composition.

  According to the coating composition of the present invention, it has excellent anticorrosion properties, and does not generate hydrogen gas in the coating film even when coating with an excessive thickness under high humidity conditions, so that it can be used on site. It is possible to provide a coating composition having a wide coating application range. Further, according to the anticorrosion method and the coated body of the present invention, it is possible to provide an anticorrosion method and a coated body using such a coating composition.

  Hereinafter, the coating composition of the present invention will be described in detail. The coating composition of the present invention comprises (A) a metal lower than iron, (B) a binder resin, (C) an adhesion promoter, and (D) water, and (B) a binder resin. Contains at least one resin selected from an acrylic resin, an epoxy resin, and an epoxy ester resin, and (C) the adhesion promoter is at least one compound selected from a phosphate ester and a sulfonate ester. It is characterized by.

  The coating composition of the present invention contains (A) a metal which is lower than iron. In the present specification, the term "metal lower than iron" means a metal having a higher ionization tendency than iron or an alloy containing the metal, and includes a single metal such as zinc, aluminum, manganese, and magnesium or an alloy thereof. . Hereinafter, “(A) a metal lower than iron” is also referred to as component (A). By coating a substrate containing iron or a metal more noble than iron with a coating composition containing the component (A), the substrate can be provided with corrosion resistance. Such a coating composition that imparts anticorrosion properties to an object to be coated is also referred to as an anticorrosion coating composition. In this specification, the term “metal noble than iron” means a metal having a lower ionization tendency than iron or an alloy containing the metal.

  (A) It is preferable that the metal lower than iron is powdery from the viewpoint of dispersing in a paint or a coating film. In the coating composition of the present invention, the content of the component (A) is preferably from 40 to 80% by weight. Component (A) may be used alone or in combination of two or more. As the component (A), a commercially available product can be used.

  In the coating composition of the present invention, the content of a metal which is more noble than iron in the nonvolatile component (A) can be exemplified to be 60 to 90% by weight, and may be 70 to 90% by weight. preferable. Here, the non-volatile component refers to a component excluding a volatile component such as water or an organic solvent, and is a component that will eventually form a coating film. Components remaining after drying at 60 ° C. for 60 minutes are treated as nonvolatile components. In the coating composition of the present invention, the nonvolatile content is preferably from 75 to 90% by weight.

  In the coating composition of the present invention, the metal (A), which is more base than iron, is preferably zinc from the viewpoint of corrosion resistance. In the coating composition of the present invention, the content of zinc in the nonvolatile components is preferably 70% by weight or more. Such a coating composition containing a large amount of zinc is referred to as a zinc-rich paint. Further, in the coating composition of the present invention, it is also preferable to use a zinc-based alloy such as zinc nickel, zinc iron, tin zinc and the like.

  In the coating composition of the present invention, (A) the metal which is lower than iron is measured by a natural drop method from the viewpoints of dispersibility in the coating, workability at the time of mixing, and anticorrosion of the coating film. The specific gravity is preferably 1.0 or more, and particularly preferably 2.0 or more. Here, the method of calculating the bulk specific gravity of the component A by the natural fall method is as follows: 100 g (m) of the component A is measured with a precision balance and gradually dropped into a 200 mL measuring cylinder (minimum scale unit: 2 mL) using a funnel. After gently tilting the measuring cylinder and carefully leveling the uppermost sample surface without consolidation, the bulk volume (V0) at that time is read to the minimum scale unit. Then, the bulk specific gravity (g / mL) was calculated by m / V0. As the bulk specific gravity in the present invention, an average value of five measurements was adopted.

In the coating composition of the present invention, it is preferable that the metal (A), which is more base than iron, has a volume average particle diameter in the range of 3 to 15 μm. In this specification, the volume average particle diameter refers to a 50% particle diameter (D ₅₀ ) of the volume-based particle size distribution, and is measured by a laser diffraction / scattering type particle size distribution analyzer (for example, SALD-7000: manufactured by Shimadzu Corporation). It can be determined from the particle size distribution measured with the use. The particle diameter in the present specification is represented by a sphere equivalent diameter obtained by a laser diffraction / scattering method.

  The coating composition of the present invention contains (B) a binder resin. Hereinafter, “(B) binder resin” is also referred to as component (B). The component (B) is not particularly limited, and examples thereof include a binder resin that is commonly used in water-based paints in the paint industry, regardless of a water-soluble resin or a water-dispersible resin. In addition, the component (B) may be a binder resin used in a one-pack coating composition or a binder resin used in a two-pack coating composition used in combination with a curing agent described below. Good. Specific examples of the component (B) include an acrylic resin, a silicone resin, an acrylic silicone resin, a styrene acrylic copolymer resin, a polyester resin, a fluororesin, a rosin resin, a petroleum resin, a coumarone resin, a phenol resin, a urethane resin, and a melamine resin. Urea resin, epoxy resin, cellulose resin, xylene resin, alkyd resin, aliphatic hydrocarbon resin, butyral resin, maleic acid resin, fumaric acid resin, vinyl resin, amine resin, ketimine resin and the like. Among these, the binder resin (B) preferably contains at least one resin selected from an acrylic resin, an epoxy resin, and an epoxy ester resin from the viewpoint of excellent adhesion to a substrate and corrosion resistance. More preferably, it contains a resin. The component (B) may be used alone or in a combination of two or more.

  Acrylic resin is a polymer of acrylic esters or methacrylic esters, for example, by polymerizing one or more of acrylic components selected from acrylic acid, methacrylic acid and its esters, amides and nitriles. Examples of the polymer include a polymer obtained by polymerizing an acrylic component and a non-acrylic component such as styrene.

  The epoxy resin is preferably a resin having at least two epoxy groups in one molecule, for example, a resin obtained by reacting a polyhydric alcohol or a polyhydric phenol with halohydrin, and specific examples thereof include: Bisphenol A epoxy resin, halogenated bisphenol A epoxy resin, novolak epoxy resin, polyglycol epoxy resin, bisphenol F epoxy resin, epoxidized oil, 1,6-hexanediol diglycidyl ether and neopentyl glycol diglycidyl Ether and the like.

  The epoxy ester resin is a resin having an ester moiety obtained by reacting a carboxyl group of a carboxylic acid such as acrylic acid or methacrylic acid with an epoxy group of the epoxy resin.

  In the coating composition of the present invention, the content of the binder resin (B) is preferably in the range of 5 to 30% by weight, and more preferably in the range of 10 to 20% by weight. Further, in the coating composition of the present invention, the content of the binder resin (B) in the nonvolatile components can be exemplified to be 5 to 30% by weight, and preferably 10 to 30% by weight.

  The coating composition of the present invention can include a curing agent. The curing agent that can be used in the present invention is appropriately selected according to the type of the resin used, and a curing agent that is commonly used in the paint industry can be used. These curing agents may be used alone or in combination of two or more. The content of the curing agent is appropriately adjusted according to the amount of the reactive group with the curing agent contained in the resin.However, in the coating composition of the present invention, the content of the curing agent in the nonvolatile components is For example, it is preferably 1.0 to 15% by weight.

  For example, an isocyanate-based curing agent can be suitably used for a resin containing a hydroxyl group (such as a hydroxyl group-containing acrylic resin). Specific examples include tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, 4,4′-methylene bis (cyclohexyl isocyanate), methylcyclohexane diisocyanate, bis (isocyanatomethyl) cyclohexane, isophorone diisocyanate, In addition to dimer acid diisocyanate and lysine diisocyanate, modified products of these polyisocyanates can be mentioned. Specific examples of the modified product include a biuret modified product, an isocyanurate modified product, an adduct modified product (for example, a trimethylolpropane adduct), an allophanate modified product, and a uretdione modified product.

  Further, an amine-based curing agent can be suitably used for the epoxy resin. Specific examples include aliphatic diamines such as ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, triaminopropane, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, isophoronediamine, and 1,3-bisaminomethylcyclohexane. Polyamines; aromatic polyamines such as phenylenediamine, metaxylylenediamine, paraxylylenediamine, and diaminodiphenylmethane; other polyamines such as polyoxyethylene diamine, polyoxypropylene diamine, triethylene glycol diamine, and tripropylene glycol diamine Compounds and modified polyamine compounds obtained by modifying the amino groups of these amine compounds. Known methods can be used to modify the amine compound. Examples of the modification reaction include amidation of an amino group, Mannich reaction of an amino group and a carbonyl compound, and addition reaction of an amino group and an epoxy group. Can be Here, a modified polyamine compound in which an epoxy group or the like is added to an amino group is called an adduct-type modified polyamine compound, and an epoxy adduct-type modified polyamine compound in which an epoxy group is added to an amino group is preferable.

  The coating composition of the present invention is preferably a coating composition containing (B) an epoxy resin as a binder resin and containing an amine compound as a curing agent, from the viewpoint of excellent adhesion to a substrate and corrosion resistance.

  The coating composition of the present invention contains an adhesion promoter, and contains, as the adhesion promoter, (C) an adhesion promoter which is at least one compound selected from a phosphoric acid ester compound and a sulfonic acid ester compound. Hereinafter, “(C) adhesion promoter” is also referred to as component (C). The adhesion promoter is a component that is blended in the paint to improve the adhesion between the coating film and the substrate (particularly, a metal-based substrate). Among these adhesion promoters, a phosphate ester compound or By blending the adhesion promoter, which is a sulfonic acid ester compound, with the coating composition containing the component (A), hydrogen gas is generated in the coating film even when the film is applied with an excessive thickness under high humidity conditions. As a result, it is possible to prevent swelling of the coating film, so that it is possible to provide a coating composition having a wide range of application on site.

  In the present specification, the “coating environment” refers to an environment in which painting is performed. For example, when a structure is painted, the outside is the painting environment. The coating composition of the present invention can prevent the generation of hydrogen gas in a coating film even when coating with an excessive film thickness is performed under high humidity conditions. For example, the relative humidity is 60 to 100%, particularly, Can be sufficiently prevented from occurring even under coating conditions in which the dry film thickness is 75 to 100% and the dry film thickness is 150 μm or more, particularly 300 μm or more. In addition, if the coating environment is low temperature, it takes more time to dry, and if the drying temperature is high, the surface is easy to dry and at the same time the zinc and water react easily, so hydrogen gas generation also affects the coating temperature. However, the coating composition of the present invention can be used, for example, under coating conditions in which the temperature is 5 ° C. to 35 ° C., the relative humidity is 60% to 100%, and the dry film thickness is 300 μm to 500 μm. The occurrence of swelling can be sufficiently prevented.

Adhesion promoters, for example, those having a site that forms some bond with the surface of the metal-based substrate and a site having high compatibility with the resin constituting the coating film in the molecule are known, In the coating composition, the (C) adhesion promoter, which is a phosphate compound or a sulfonic acid ester compound, is derived from a structure derived from phosphoric acid (P (= O) (-O) ₃ ) or a sulfo group. By bonding to the surface of the component (A) such as zinc through the structure (S (= O) ₂ (-O)) to cover the surface, hydrogen generated by the reaction of the component (A) with water in the drying process Formation can be effectively suppressed. In addition, since the adhesion of the coating film can be improved, when the coating film is finally formed, as in the original use of the adhesion promoter, the structure derived from the phosphoric acid or the sulfo group of the component (C) is used. The structure is believed to be bonded to the surface of the metal-based substrate. In fact, since the coating composition of the present invention has an excellent anticorrosion property, at least a part of the component (C) covering the surface of the component (A) in the coating composition contains at least a metal-based group. It is considered to be bonded to the surface of the material.

  In the coating composition of the present invention, (C) the adhesion promoter preferably has a molecular weight in the range of 300 to 3000, and has a molecular weight in the range of 400 to 2000, particularly in the range of 500 to 1200. Is more preferable. As the molecular weight of the component (C) increases, the proportion of a site having high compatibility with the resin constituting the coating film in the molecule increases. However, if the molecular weight is too high, the metal base or the component (A) The component (C) having a molecular weight in the above-specified range is preferable because the ability to bind to the compound is weakened.

As used herein, the term "phosphate compound" refers to a compound in which some or all of the hydrogen atoms of the three OH groups of phosphoric acid (O = P (OH) ₃ ) have been substituted with organic groups. A compound in which hydrogen of one OH group of the three OH groups of phosphoric acid is substituted with an organic group is also referred to as a phosphoric acid monoester, and hydrogen of two OH groups of the three OH groups of phosphoric acid is A compound substituted with an organic group may be referred to as a phosphoric diester, and a compound in which all of the OH groups of the three OH groups of phosphoric acid have been substituted with an organic group may be referred to as a phosphoric acid triester.
In the present specification, a phosphoric acid ester having one or two OH groups among the three OH groups possessed by phosphoric acid (including a salt or an ionic form), such as a phosphoric acid monoester or a phosphoric acid diester, is used. Also referred to as the free acid of a phosphate ester. In the coating composition of the present invention, the phosphate compound is preferably a free acid of a phosphate ester.
Further, the organic group obtained by substituting the hydrogen of the OH group of the phosphoric acid is preferably a hydrocarbon group. The hydrocarbon group may be linear or branched, but is preferably a linear hydrocarbon group from the viewpoint of compatibility with the binder resin (B). , An alkyl group, an alkenyl group and the like. As the alkyl group and the alkenyl group, an alkyl group having 10 to 30 carbon atoms (an alkyl group having 10 to 30 carbon atoms) and an alkenyl group having 3 to 30 carbon atoms (an alkenyl group having 3 to 30 carbon atoms) are preferable.
In the coating composition of the present invention, (C) the adhesion promoter is preferably a compound having at least one group selected from an alkyl group and an allyl group, and at least one compound selected from an alkyl group and an allyl group. In the case of a phosphoric acid ester compound having a group, the free acid of an alkyl / allyl phosphoric acid ester (having one OH group of phosphoric acid, hydrogen of one OH group being substituted with an alkyl group, A phosphoric acid ester in which the hydrogen of the group is substituted with an allyl group), a free acid of an alkyl phosphoric acid ester (having one or two OH groups of phosphoric acid, and hydrogen of the remaining two or one OH group being Phosphoric acid ester substituted with an alkyl group) is more preferred.
The organic group obtained by substituting the hydrogen of the OH group of phosphoric acid may be an organic group based on a polymer. For example, Disperbyk-180 manufactured by BYK-Chemie, described below, is an alkylol ammonium salt of a copolymer containing a phosphate group, which is an alkylol ammonium salt of a copolymer (an organic group based on a polymer). It is a phosphoric ester compound in which the hydrogen of the OH group of the acid is substituted, and corresponds to the component (C) in the present specification.

  In the coating composition of the present invention, specific examples of the (C) phosphate compound that can be used as an adhesion promoter include a phosphate compound of a polyester / polyether polymer, a phosphate compound of a polyether polymer, and an alkyl phosphate The free acid of an ester compound, the free acid of an alkyl / allyl phosphate ester compound, and the like can be mentioned, and commercially available products can be suitably used. Commercial products include Lubrizol's LUBRIZOL 2061 and 2062H, Big Chemie's Disperbyk-110, 111, 180, 102, 103 and 106, Toho Chemical Industries' Phosphanol RE-610 and RS-710, and Kusumoto Kasei's. Dispalon DA-325, DA-375 and the like. Of these, LUBRIZOL 2061 and 2062H manufactured by Lubrizol and Disperbyk-180 manufactured by BYK-Chemie, which are free acids of phosphate ester, are most preferable because they can effectively protect the zinc surface.

In the present specification, the “sulfonic acid ester compound” is a compound in which hydrogen of a sulfo group (SO ₃ H) of a sulfonic acid is substituted with an organic group, and has a formula of R ¹ S (＝ O) ₂ (OR ² ). Can be represented by Here, R ¹ and R ² are independent and may be the same or different, but are preferably a hydrocarbon group. The hydrocarbon group may be linear or branched, but is preferably a linear hydrocarbon group from the viewpoint of compatibility with the binder resin (B). , An alkyl group, an alkenyl group and the like. As the alkyl group and the alkenyl group, an alkyl group having 5 to 30 carbon atoms (an alkyl group having 5 to 30 carbon atoms) and an alkenyl group having 3 to 30 carbon atoms (an alkenyl group having 3 to 30 carbon atoms) are preferable.
In the coating composition of the present invention, (C) the adhesion promoter is preferably a compound having at least one group selected from an alkyl group and an allyl group, and at least one compound selected from an alkyl group and an allyl group. In the case of a sulfonate compound having a group, allyl alkyl sulfonate (a compound in which R ¹ is an alkyl group and R ² is an allyl group in the above formula) is more preferable.
The organic group obtained by substituting the hydrogen of the sulfo group of the sulfonic acid is preferably an organic group based on a polymer.

  In the coating composition of the present invention, specific examples of (C) a sulfonate compound that can be used as an adhesion promoter include ammonium salt of polyoxyethylene allyloxymethylalkoxyethyl sulfonate and sodium sulfonate of polyoxyalkylene methacrylate. Salts, sodium salts of alkyl allyl diesters of sulfosuccinic acid, sulfonates of polyoxyethylene allyl glycidyl nonyl phenyl ether and the like can be used, and commercially available products can be suitably used. As commercially available products, Latemul S-180A manufactured by Kao Corporation, Eleminol JS-2 manufactured by Sanyo Kasei, Aqualon KH-10, KH-20, Aqualon HS-10, Aqualon BC-10 manufactured by Daiichi Kogyo Seiyaku, Asahi Denka Kogyo Adecaria Soap SE-10N, SE-20N, Adecaria Soap SR-10, SR-20, ER-20, and AQUALON RS-20, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

  In the coating composition of the present invention, the content of the adhesion promoter (C) is preferably in the range of 0.1 to 10% by weight, and more preferably in the range of 0.1 to 5% by weight. More preferably, it is particularly preferably in the range of 0.1 to 4% by weight. Further, in the coating composition of the present invention, the content of the adhesion promoter (C) in the nonvolatile components is preferably from 0.1 to 5.0% by weight. If the content of the component (C) is increased, the effect of preventing the occurrence of swelling of the coating film can be enhanced, but if the content of the component (C) is too large, the surface of the component (A) becomes unnecessarily large. It is preferable that the content of the component (C) is within the above-specified range because the component (A) may be coated and the sacrificial corrosion protection performance of the component (A) may be reduced.

  In the coating composition of the present invention, (A) / [(B) + (C)] is the weight ratio of the metal lower than iron (A) to the total weight of the binder resin (B) and the adhesion promoter (C). = 3-15, more preferably 3-10, particularly preferably 3-5. By increasing the weight ratio of the component (A) to the weight of the component (B) and the component (C), the effect of imparting sacrificial anticorrosion performance can be enhanced, but if the weight ratio of the component (A) is too high. The weight ratio (A) / [(B) + (C)] is preferably within the above-specified range, since the physical properties of the coating film may be reduced.

  In the coating composition of the present invention, the weight ratio of the adhesion promoter (C) to the weight of the metal lower than (A) iron is in the range of (C) / (A) = 0.001 to 0.2. It is more preferably in the range of 0.001 to 0.15, and further preferably in the range of 0.002 to 0.1. By increasing the weight ratio of the component (C) to the weight of the component (A), the effect of suppressing the generation of hydrogen gas can be enhanced. However, if the weight ratio of the component (C) is too high, the component (A) ) May unnecessarily coat the surface, which may reduce the effect of improving the sacrificial corrosion protection performance of the component (A). Therefore, the weight ratio (C) / (A) may be within the above-specified range. preferable.

  The coating composition of the present invention contains (D) water, but is preferably an aqueous coating containing water as a main solvent. In the coating composition of the present invention, the water content is preferably 2 to 50% by weight, more preferably 2 to 25% by weight. Further, the coating composition of the present invention can be made completely water-based, and the proportion of water in the solvent used is preferably 50% by weight or more, more preferably 80% by weight or more, and most preferably 100% by weight or more. % By mass. In addition, "(D) water" is also called component (D).

  The coating composition of the present invention can include a pigment. The pigment that can be used in the present invention is not particularly limited, and pigments commonly used in the paint industry can be used. However, (A) those that are classified as metals lower than iron are excluded from the pigment referred to in the present specification. Specific examples include coloring pigments such as titanium dioxide, iron oxide, and carbon black, and extenders such as silica, talc, mica, calcium carbonate, and barium sulfate. In addition, rust-preventive pigments, bright pigments, and the like are also included. These pigments may be used alone or in combination of two or more. In the coating composition of the present invention, the content of the pigment is preferably in the range of 0.5 to 10% by weight.

  In the coating composition of the present invention, as other components, an organic solvent, a dye, a surface conditioner, a wetting agent, a dispersant, an emulsifier, a thickener, an anti-settling agent, an anti-skinning agent, an anti-sagging agent, and defoaming Agents, anti-segregation agents, leveling agents, desiccants, plasticizers, film-forming aids, fungicides, antibacterial agents, insecticides, light stabilizers, ultraviolet absorbers, antistatic agents, and conductivity-imparting agents. It can be appropriately compounded according to the purpose. Commercially available products can be suitably used for these components.

  The coating composition of the present invention can be prepared by mixing various components appropriately selected as necessary. Since the coating composition of the present invention contains (A) a metal which is lower than iron and (D) water, the components (A) and (D) constituting the coating react with each other to generate hydrogen gas. Because of the fear, it is preferably prepared immediately before coating. When the coating composition of the present invention is a two-pack type coating composition, a main agent and a curing agent are prepared in advance by mixing various components appropriately selected as necessary, and the main agent is used during coating. And a curing agent. The curing agent may be the curing agent itself or a mixture with another component.

  The viscosity at 23 ° C. of the coating composition of the present invention is preferably 0.1 to 120 dPa · s. The viscosity can be measured, for example, with a Visco Tester (Viscometer) manufactured by Rion Corporation.

  Next, the anticorrosion method of the present invention will be described in detail. The anticorrosion method of the present invention includes a step of coating a metal-based substrate with the above-described coating composition of the present invention to form a coating film. According to the anticorrosion method of the present invention, it is possible to perform coating of a metal-based substrate without generating hydrogen gas in the coating film even when the coating is performed with an excessive film thickness under high humidity conditions, and is excellent. Corrosion resistance can be imparted to the metal base material.

  In the anticorrosion method of the present invention, the metal-based substrate is a substrate containing a metal (preferably iron or a metal nobler than iron, more preferably iron) as at least a part of the material. And a composite substrate formed from a metal and a non-metallic material. The anticorrosion method of the present invention is characterized in that the metal base material is a steel material such as a steel bar, a steel plate, a steel pipe, or a structure (steel structure) such as a bridge, a tank, a plant, or a ship constructed or constructed using the steel material. Is particularly preferred. In addition, the metal-based substrate also includes a substrate subjected to various surface treatments. In addition, the metal-based substrate may be subjected to a primer treatment, or an old coating film may be applied to at least a part of the surface of the substrate (when the coating using the coating composition of the present invention is performed in the anticorrosion method of the present invention). May be present).

  In the anticorrosion method of the present invention, the coating means of the coating composition of the present invention is not particularly limited, and known coating means, for example, spray coating, roller coating, brush coating, iron coating, spatula coating and the like can be used.

  In the anticorrosion method of the present invention, the temperature at the time of coating is not particularly limited, and coating can be performed in a wide temperature range, and a range of 5 to 40 ° C can be exemplified.

  In the anticorrosion method of the present invention, the relative humidity at the time of coating is not particularly limited, and coating can be performed in a wide temperature range, and a range of 5 to 95% can be exemplified. The coating can be performed without causing swelling in the coating film even in a high-humidity environment in the range of up to 95%.

  In the anticorrosion method of the present invention, the dry film thickness formed from the coating composition of the present invention is not particularly limited and may be in the range of 30 to 75 μm, for example, in the range of 100 to 500 μm. Even if the film thickness is excessive, the coating can be performed without generating hydrogen gas in the coating film.

In the anticorrosion method of the present invention, the coating conditions of the metal-based substrate with the coating composition of the present invention are, for example, a coating environment of a temperature of 5 ° C. to 40 ° C. and a relative humidity of 50 to 95%, and a dry film thickness of 30 to 95%. When the coating conditions are such that a coating film having a thickness of 500 μm is formed, the generation of hydrogen gas in the coating film can be sufficiently prevented.
In particular, the anticorrosion method of the present invention has a temperature of 20 to 40 ° C., a relative humidity of 60 to 95%, and a dry film thickness of 250 to 500 μm. Even when the relative humidity is 80 to 95% and the dry film thickness is 400 to 500 μm, the generation of hydrogen gas in the coating film can be sufficiently prevented. It is suitable even under coating conditions.

  In the anticorrosion method of the present invention, a coating film (first coating film) formed from the coating composition of the present invention is coated with an aqueous coating different from the coating composition of the present invention, and a further coating film (first coating film) is formed. (A second coating film).

  In the anticorrosion method of the present invention, conventionally known various paints can be used as the water-based paint as long as it is water-based paint using water as a main solvent. The water-based paint is a resin, a coloring agent such as a coloring pigment or a dye, an extender pigment, a rust-preventive pigment, a bright pigment, a wetting agent, a dispersant, an emulsifier, a resin bead, a viscosity modifier, an anti-skinning agent, an antifoaming agent, Anti-segregation agents, leveling agents, drying agents, curing agents, curing catalysts, plasticizers, film-forming aids, rust preventive pigments, fungicides, antibacterial agents, insecticides, light stabilizers, ultraviolet absorbers, antistatic An agent, a conductivity-imparting agent and the like can be appropriately compounded according to the purpose. Commercially available products can be suitably used for these components. The aqueous paint can be prepared by mixing various components appropriately selected as necessary.

  In the anticorrosion method of the present invention, the means for applying the water-based paint is not particularly limited, and known coating means, for example, spray coating, roller coating, brush coating, iron coating, spatula coating and the like can be used. Further, the dry film thickness formed from the aqueous paint is not particularly limited, and may be in the range of 30 to 300 μm.

  In the anticorrosion method of the present invention, the means for drying and curing the coating film is not particularly limited, and is appropriately selected depending on the type of the paint used. For example, drying by heating, curing by heating, irradiation with ultraviolet light, or the like may be performed, or a coating (eg, a two-component coating) in which the curing reaction proceeds spontaneously or a coating capable of natural drying (eg, a volatile solvent) System paint), it is not necessary to employ a special drying or curing means. In the anticorrosion method of the present invention, when forming a plurality of coating films, the coating film may be dried or cured each time a coating film is formed, or the coating film may be formed after forming a plurality of coating films. May be dried or cured. In particular, the anticorrosion method of the present invention is suitable for coating for use in steel structures, and enables formation of a coating film having excellent anticorrosion properties when dried by natural drying.

  Next, the coated body of the present invention will be described in detail. The coated body of the present invention includes a metal-based substrate and a coating film formed on the metal-based substrate, wherein the coating film is formed from the above-described coating composition of the present invention. And ADVANTAGE OF THE INVENTION According to the coating body of this invention, the swelling does not generate | occur | produce in a coating film, and it can provide the coating body excellent in anticorrosion property.

  In the coated body of the present invention, the metal-based substrate is as described in the anticorrosion method of the present invention. Further, a coating film (first coating film) formed from the coating composition of the present invention can be obtained by coating a metal-based substrate with the coating composition of the present invention. As described in the anticorrosion method of the invention. In the coated body of the present invention, the first coating film is not particularly limited and may be in the range of 30 to 75 μm, for example, in the case of an excessive film thickness in the range of 100 to 500 μm. There may be.

  The coated body of the present invention can include a further coating film formed on the first coating film, wherein the further coating film is formed from an aqueous coating different from the coating composition of the present invention. Have been. A coating film (second coating film) formed from the water-based paint is obtained by applying the first coating film with the water-based paint. Here, the water-based paint different from the paint composition of the present invention and the coating of the first coating film with the water-based paint are as described in the anticorrosion method of the present invention. In the coated body of the present invention, the second coating film is not particularly limited, and may have a range of 30 to 300 μm.

  Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples. In the following examples, the description of "part" and "%" indicating the content of each component means "part by weight" and "% by weight", respectively.

(Example 1)
As the base material, a grid blasted steel plate (150 × 70 × 3.2 mm) having a substrate adjustment degree of ISO 8501-1 Sa2.5 was used. After mixing epoxy resin emulsion (Note 1), LUBRIZOL 2061 (Note 6) as main agent, and amine resin emulsion (Note 10) as water and curing agent, zinc powder (Note 12) is mixed, and water-based anticorrosive paint composition is mixed. Was prepared.

(Examples 2 to 23 and Comparative Examples 1 to 7)
A water-based anticorrosion coating composition was prepared in the same manner as in Example 1 according to the formulations in Tables 1 to 4.

The components shown in Tables 1 to 4 are described below.
(Note 1) Bisphenol A type epoxy resin emulsion, resin solid content 55%, epoxy equivalent 495 g / eq, (trade name: Epolsion EA55, manufactured by NSC Japan)
(Note 2) Bisphenol A type epoxy resin emulsion, resin solid content 62%, epoxy equivalent 200g / eq, (trade name: Epolsion HD2, manufactured by NSC Japan)
(Note 3) Bisphenol F type epoxy resin emulsion, resin solid content 70%, epoxy equivalent 200 g / eq, (trade name: JER W8735R70, manufactured by Mitsubishi Chemical Corporation)
(Note 4) Epoxy ester resin emulsion, resin solid content 40%, (trade name Watersol EFD-5570, manufactured by DIC)
(Note 5) Styrene acrylic resin emulsion, resin solid content 50%, (trade name: PLIOTEC HDT 12, OMNOVA SOLUTIONS)
(Note 6) Adhesion promoter, free acid of alkyl phosphate compound (LUBRIZOL2061, manufactured by Lubrizol)
(Note 7) Adhesion promoter, free acid of alkyl / allyl phosphate ester compound (brand name LUBRIZOL2062H, manufactured by Lubrizol)
(Note 8) An adhesion promoter, an alkylol ammonium salt of a copolymer containing a phosphate ester group (trade name: Disperbyk-180, manufactured by BYK Chemie)
(Note 9) Adhesion promoter, sulfonate compound, solid content 25% (trade name SR-1025, manufactured by ADEKA)
(Note 10) Modified aliphatic polyamine resin emulsion, resin solid content 56%, (trade name: Fujicure FXS-918-FA, manufactured by T & K TOKA)
(Note 11) Modified polyamidoamine (water-soluble), resin solid content 60%, (trade name: JER Cure WD11M60, manufactured by Mitsubishi Chemical Corporation)
(Note 12) Zinc powder A: average particle diameter 4 μm, bulk specific gravity 2.5
(Note 13) Zinc powder B: average particle diameter 7 μm, bulk specific gravity 3.1
(Note 14) Aluminum powder: average particle diameter 25 μm, bulk specific gravity 1.2

  Next, the obtained water-based anticorrosive coating composition was diluted with water in advance to adjust to an appropriate coating viscosity (23 ° C., 0.1 to 5 dPa · s, measured by a viscometer (viscometer) manufactured by Rion Co., Ltd.). , 23 ° C., 50% relative humidity, and applied to both sides of the substrate using an air spray so that the dry film thickness becomes 70 to 80 μm. The specimen was dried for 7 days under the condition of 50% relative humidity to prepare a test piece. For the hydrogen generation test, test plates were prepared under different conditions, and the details will be described below. These test pieces were subjected to the following evaluation tests. The results are shown in Tables 1 to 4.

<Coating workability>
The atomization state of the paint sprayed at the time of the air spray coating was visually judged according to the following criteria.
(Evaluation criteria)
：: Good atomization and smooth coating film surface.
Δ: Spray particles are discharged intermittently, or the coating film surface has irregularities.
X: Poor atomization cannot be performed due to poor atomization, or the surface of the coating film has large irregularities and the appearance of the coating film is extremely poor.

<Adhesion test>
In accordance with the adhesion test method specified in JIS K 5600, 100 pieces of 2 mm squares were prepared on a test piece using a cutter knife, and a peeling test was performed with a cellophane tape, and visually judged according to the following criteria.
(Judgment criteria)
：: No peeling on the grid, no abnormality on the coating film surface.
Δ: The number of eyes remaining on the coating film is 95 or more.
X: The number of eyes remaining on the coating film is 94 or less.

<Corrosion protection>
The test specimen was subjected to a combined cycle test for 30 days (720 hours) in accordance with JIS K 5600-7-9 (2006) cycle corrosion test method cycle D. The appearance of the coating film was visually judged according to the following criteria.
(Judgment criteria)
◎: No abnormality around the cross-cut portion ○: Red rust less than 1 mm in diameter around the cross-cut portion △: Red rust or blister with a diameter of 1 mm to less than 2 mm around the cross-cut portion ×: Around the cross-cut portion , Red rust and blisters with a diameter of 2 mm or more

<Hydrogen generation test>
The obtained water-based anticorrosion coating composition was subjected to the following conditions: 23 ° C., 40% relative humidity condition 1, 23 ° C., 60% relative humidity condition 2, and 23 ° C., 90% relative humidity condition 3. It was applied to one surface of the substrate using an applicator so that the dry film thickness was 250 to 350 μm, and was dried under each of the conditions 1 to 3 for 3 days to prepare a test piece.
The generation of hydrogen gas and the occurrence of blistering of the coating film during the drying process for 3 days were visually judged according to the following criteria. The results are shown in Tables 1 to 4.
(Judgment criteria)
◎: No hydrogen was generated, and there was no abnormality on the coating film surface.
：: Hydrogen gas is generated, and blisters are generated in less than 5% of the coating film area.
Δ: Hydrogen gas is generated, and blisters are generated in 5% or more and less than 20% of the coating film area.
×: Hydrogen gas is generated, and blisters are generated in 20% or more of the coating film area.

Claims (15)

  A coating composition comprising (A) a metal lower than iron, (B) a binder resin, (C) an adhesion promoter, and (D) water, wherein (B) the binder resin is an acrylic resin, an epoxy resin, And at least one resin selected from epoxy ester resins, and (C) the adhesion promoter is at least one compound selected from a phosphoric acid ester compound and a sulfonic acid ester compound. object.   The coating composition according to claim 1, wherein (C) the adhesion promoter is a compound having at least one group selected from an alkyl group and an allyl group.   (C) The coating composition according to claim 1 or 2, wherein the adhesion promoter is a free acid of a phosphoric ester.   (C) The coating composition according to any one of claims 1 to 3, wherein the molecular weight of the adhesion promoter is in the range of 300 to 3000.   (A) The coating composition according to any one of claims 1 to 4, wherein the metal lower than iron is zinc.   (A) The weight ratio of the metal lower than iron to the total weight of the binder resin and (C) the adhesion promoter is (A) / [(B) + (C)] = 3 to 15. The coating composition according to any one of claims 1 to 5, wherein the coating composition is provided.   (B) The content of the binder resin in the coating material is in the range of 5 to 30% by weight, and the content of the adhesion promoter (C) in the coating material is in the range of 0.1 to 10% by weight. The coating composition according to any one of claims 1 to 6, characterized in that:   The weight ratio of the adhesion promoter (C) to the weight of the metal (A) which is lower than iron is in the range of (C) / (A) = 0.001 to 0.2. The coating composition according to any one of claims 1 to 7.   The coating composition according to any one of claims 1 to 8, wherein the binder resin (B) is an epoxy resin, and further contains an amine compound as a curing agent.   An anticorrosion method comprising a step of coating a metal-based substrate with the coating composition according to claim 1 to form a coating film.   The coating condition of the metal-based substrate with the coating composition is a coating condition for forming a coating film having a dry film thickness of 30 to 500 μm under a coating environment of a temperature of 5 ° C. to 40 ° C. and a relative humidity of 50 to 95%. The anticorrosion method according to claim 10.   The coating condition of the metal-based substrate with the coating composition is a coating condition for forming a coating film having a dry film thickness of 250 to 500 μm under a coating environment of a temperature of 20 ° C to 40 ° C and a relative humidity of 60 to 95%. The anticorrosion method according to claim 10.   The anticorrosion method according to any one of claims 10 to 12, further comprising a step of coating the coating film with an aqueous paint different from the coating composition to form a further coating film.   A coated body, comprising: a metal-based substrate; and a coating film formed on the metal-based substrate, wherein the coating film is formed from the coating composition according to claim 1.   The coated body according to claim 14, further comprising a further coating film formed on the coating film, wherein the further coating film is formed from an aqueous paint different from the paint composition.