JP6017912B2 - Water-based anti-corrosion paint composition and coated product thereof - Google Patents

Description

  The present invention relates to an aqueous rust preventive coating composition preferably used as a water rust preventive paint and a coated article using the same. More specifically, the obtained coating film is excellent in rust prevention, adhesion to the substrate, adhesion to the substrate after being subjected to repeated high and low temperatures, and impact resistance, and is also dry. The present invention relates to a water-based anti-corrosion paint composition capable of realizing a water-based anti-corrosion paint having good stability and storage stability and a coated product thereof.

In recent years, from the viewpoint of protecting the global environment, the transition from solvent-based paints to water-based paints is progressing in various paints. Even rust preventive paints are shifting from solvent-based to water-based paints, but conventional water-based rust preventive paints have a major problem that the rust preventive properties of the resulting coating film are inferior to solvent-based rust preventive paints.
Many prior arts have been disclosed in order to solve such problems of water-based anticorrosive paints. For example, a method using a copolymer latex having a specific composition and a specific glass transition temperature (Patent Document 1), and a styrene-butadiene copolymer each having one or more glass transition temperatures within two specific temperature ranges. A method using an emulsion composition in which a polymer emulsion, a nonionic surfactant, and a polycarboxylate are mixed in a specific ratio (Patent Document 2), and further, an aqueous copolymer resin emulsion, a rust preventive pigment, a hydrophilic organic A method using a water-based resin coating composition (Patent Document 3) containing a solvent at a specific ratio has been proposed.

JP 11-35872 A JP 2008-19143 A JP 7-41701 A

  However, it is a room-temperature dry type, and has the same or better anti-corrosion properties than those obtained from solvent-based paints, and at the same time other characteristics than anti-corrosion properties, such as adhesion to the substrate, repeated high and low temperatures. A coating film having a high level of adhesion and impact resistance to the base material after being applied (hereinafter referred to as repeated heating and cooling), and a water-based rust preventive with good drying and storage stability. The reality is that paint has not been realized.

  Therefore, the present invention provides a coating film that is excellent in rust prevention, as well as adhesion to the substrate, adhesion to the substrate after repeated heating and cooling, and impact resistance, as well as drying and storage. An object of the present invention is to provide an aqueous rust preventive coating composition that can realize a room temperature dry type water rust preventive paint having good stability and a coated product using the same.

  As a result of intensive studies to solve the above problems, the present inventors have included a conjugated diene monomer and a monomer having a hydroxyalkyl group as an essential monomer, and contain them in a specific ratio. A copolymer latex having a specific composition obtained by emulsion polymerization of a monomer mixture in which the amount of the ethylenically unsaturated carboxylic acid monomer in the monomer mixture is equal to or less than a specific amount; The composition comprising a rust preventive pigment is dried at room temperature and is excellent in rust prevention, as well as adhesion to the substrate, adhesion to the substrate after repeated heating and cooling, and impact resistance. A coating film was provided, and it was found that drying property and storage stability were also good, and the present invention was made.

That is, the present invention provides the following water-based rust preventive coating composition and its coated product.
[1] (I) (a) 1 to 60 parts by mass of a conjugated diene monomer, (b) a monomer having a hydroxyalkyl group (excluding those corresponding to (a) a conjugated diene monomer) 0 And a monomer mixture (provided that (a) + (b) + (c) of 5 to 10 parts by mass and (c) 30 to 98.5 parts by mass of other monomers copolymerizable therewith) ) = 100 parts by mass), and among the (c) other monomers, the number of parts occupied by the (c1) ethylenically unsaturated carboxylic acid monomer is the monomers (a), (b) and ( c) a copolymer latex obtained by emulsion polymerization of the monomer mixture in an amount of 0 to 2.5 parts by mass with respect to 100 parts by mass in total, and (II) a rust preventive pigment. A water-based anti-rust paint composition.
[2] Of the other monomers (c), the (c1) ethylenically unsaturated carboxylic acid monomer occupies a total of 100 masses of the monomers (a), (b), and (c). The water-based anticorrosive coating composition according to [1], which is 0 to 1.4 parts by mass with respect to parts.
[3] The number of parts occupied by the (c1) ethylenically unsaturated carboxylic acid monomer among the other monomers (c) is 100 masses in total of the monomers (a), (b) and (c). The water-based anticorrosive coating composition according to [1], which is 0 to 0.4 parts by mass with respect to parts.
[4] Any one of [1] to [3], wherein the amount of the (II) rust preventive pigment is 10 to 60 parts by mass with respect to 100 parts by mass of the solid content of the (I) copolymer latex. 2. A water-based anticorrosive coating composition according to item 1.
[5] The aqueous rust preventive coating composition according to any one of [1] to [4], wherein at least a part of the (II) rust preventive pigment is a tripolyphosphate metal salt.
[6] A coated product obtained using the water-based anticorrosive coating composition according to any one of [1] to [5].

  The aqueous rust preventive coating composition comprising a copolymer latex and a rust preventive pigment of a specific composition according to the present invention, the coating film obtained therefrom is excellent in rust preventive properties, and at the same time, adhesion to a substrate, A water-based anti-corrosion paint having unprecedented performance can be realized with excellent adhesion to the base material after repeated heating and cooling and impact resistance, as well as good drying and storage stability. And it is possible to improve the VOC problem caused by the organic solvent.

  Hereinafter, the present invention will be described in detail. The copolymer latex used in the present invention includes (a) a conjugated diene monomer, (b) a monomer having a hydroxyalkyl group (excluding those corresponding to (a) a conjugated diene monomer), and (C) a monomer mixture obtained by mixing other monomers with a specific composition, and (c1) an ethylenically unsaturated carboxylic acid monomer in the monomer mixture It is obtained by emulsion polymerization of a monomer mixture having a specific amount or less.

(A) Conjugated diene monomer (a) Examples of the conjugated diene monomer include 1,3-butadiene, isoprene, 2-chloro-1,3-butadiene, and the like. These can be used alone or in combination of two or more. Among these, 1,3-butadiene can be preferably used.

  (A) The number of parts that the conjugated diene monomer occupies in 100 parts by mass of the total monomer mixture is 1 to 60 parts by mass, preferably 3 to 50 parts by mass, and more preferably 5 to 45 parts by mass. (A) By setting the lower limit of the number of parts occupied by the conjugated diene monomer as described above, a coating film excellent in adhesion to the substrate, adhesion to the substrate after repeated heating and cooling, and impact resistance is obtained. can get. (A) By setting the upper limit of the number of parts occupied by the conjugated diene monomer, a coating film excellent in rust resistance and impact resistance can be obtained.

(B) Monomer having a hydroxyalkyl group (b) The monomer having a hydroxyalkyl group is a monomer having at least one hydroxyalkyl group, the (a) conjugated diene monomer There are no particular restrictions as long as it does not fall under. Examples thereof include ethylenically unsaturated carboxylic acid hydroxyalkyl ester monomers, allyl alcohol, N-methylol acrylamide and the like. These can be used alone or in combination of two or more. Examples of the ethylenically unsaturated carboxylic acid hydroxyalkyl ester monomer include 2-hydroxyethyl (meth) acrylate, which can be suitably used.

  (B) The part which the monomer which has a hydroxyalkyl group occupies in 100 mass parts of all the monomer mixtures is 0.5-10 mass parts, Preferably it is 1-9 mass parts, More preferably, it is 2-8 masses. Part. (B) By setting the lower limit of the number of parts occupied by the monomer having a hydroxyalkyl group as described above, a coating film having excellent adhesion to the substrate after repeated heating and cooling can be obtained. Moreover, the storage stability when used as a paint is good. (B) By setting the upper limit of the number of parts occupied by the monomer having a hydroxyalkyl group as described above, a coating film excellent in rust prevention can be obtained. Moreover, the drying property at normal temperature when used as a paint is good.

(C) Other monomer (c) The other monomer is a monomer copolymerizable with (a) a conjugated diene monomer and (b) a monomer having a hydroxyalkyl group (the above-mentioned monomer). There is no particular limitation other than that, except for those corresponding to the monomer (a) or (b).

(C) Other monomers include, for example, (c1) an ethylenically unsaturated carboxylic acid monomer, (c2) a vinyl cyanide monomer, (c3) an aromatic vinyl monomer, (c4) ) (Meth) acrylic acid alkyl ester monomers. These can be used alone or in combination of two or more.
(C) The number of parts that other monomers occupy in 100 parts by mass of the total monomer mixture is 30 to 98.5 parts by mass, and among these 30 to 98.5 parts by mass, (c1) ethylene-based The number of parts occupied by the unsaturated carboxylic acid monomer is 0 to 2.5 parts by mass, preferably 0 to 1.4 parts by mass, and more preferably 0 to 0.4 parts by mass (where (c1) + (c1 (C) the number of parts of other monomers = 30 to 98.5 parts by mass). The use of an ethylenically unsaturated carboxylic acid monomer improves the storage stability when used as a paint, but when used at 2.5 parts by mass or less, it effectively suppresses the decrease in rust resistance of the resulting coating film. be able to.

  (C1) Examples of the ethylenically unsaturated carboxylic acid monomer include monobasic ethylenically unsaturated carboxylic acid monomers such as acrylic acid and methacrylic acid, dibasic acids such as itaconic acid, maleic acid, and fumaric acid. Examples thereof include ethylenically unsaturated carboxylic acid monomers. These can be used alone or in combination of two or more.

  Examples of the (c2) vinyl cyanide monomer include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile and the like. These can be used alone or in combination of two or more. Among these, acrylonitrile can be preferably used.

  Examples of the (c3) aromatic vinyl monomer include styrene, α-methylstyrene, vinyltoluene, p-methylstyrene, and the like. These can be used alone or in combination of two or more. Among these, styrene can be preferably used.

  (C4) (Meth) acrylic acid alkyl ester monomers include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ( Examples include cyclohexyl methacrylate and dodecyl (meth) acrylate. These can be used alone or in combination of two or more. Among these, methyl (meth) acrylate and 2-ethylhexyl (meth) acrylate can be preferably used.

  In addition to the various monomers (c1) to (c4), various other copolymerizable monomers (c) can also be used in the monomer mixture in the present invention. Examples of such monomers include aminoalkyl esters such as aminoethyl acrylate, dimethylaminoethyl acrylate and diethylaminoethyl acrylate, pyridines such as 2-vinylpyridine and 4-vinylpyridine, and glycidyl acrylate. , Glycidyl esters such as glycidyl methacrylate, amides such as acrylamide, methacrylamide, N-methyl acrylamide, N-methyl methacrylamide, glycidyl methacrylamide, N, N-butoxymethyl acrylamide, and vinyl carboxylates such as vinyl acetate , Vinyl halides such as vinyl chloride, divinylbenzene, (poly) ethylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, 1,4-butanediol di (meth) Acrylate, and allyl (meth) polyfunctional vinyl monomers such as acrylates. These can be used alone or in combination of two or more.

  In the present invention, various methods can be employed for adding the monomer mixture into the polymerization system. For example, a method in which a part of the monomer mixture is added to the polymerization system in advance and the remaining monomer mixture is added continuously or intermittently after the completion of the polymerization reaction. The method of adding continuously or intermittently is mentioned. These addition methods can be combined.

  In addition, in the method of adding the monomer mixture, a so-called power feed method in which the composition of the monomer mixture continuously changes can be used.

  Examples of the method for producing the copolymer latex used in the present invention include a method of performing a polymerization reaction with a radical polymerization initiator in the presence of an emulsifier in an aqueous medium.

  Examples of the emulsifier include conventionally known non-reactive anionic emulsifiers and nonionic emulsifiers, and reactive anionic emulsifiers and nonionic emulsifiers having a radical polymerization group in the molecule. These can be used alone or in combination of two or more.

  Non-reactive anionic emulsifiers include, for example, alkyl sulfates, polyoxyethylene alkyl ether sulfates, alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl sulfosuccinates having no radical polymerization group in the molecule. Acid salt, alkyl diphenyl ether disulfonate, naphthalene sulfonic acid formalin condensate, polyoxyethylene polycyclic phenyl ether sulfate, polyoxyethylene distyrenated phenyl ether sulfate, fatty acid salt, alkyl phosphate, polyoxyethylene Examples thereof include alkylphenyl ether sulfate salts.

  Examples of non-reactive nonionic emulsifiers include, for example, polyoxyethylene alkyl ethers, polyoxyalkylene alkyl ethers, polyoxyethylene polycyclic phenyl ethers, polyoxyethylene distyrenates that do not have a radical polymerization group in the molecule. Phenyl ether, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene alkylamine, alkylalkanolamide, polyoxyethylene alkylphenyl ether, etc. It is done.

  Examples of the reactive anionic emulsifier include alkylallylsulfosuccinate (such as Elemiol JS-2 manufactured by Sanyo Chemical Industries, Ltd.) having a radical polymerization group in the molecule, ammonium polyoxyethylene alkylpropenyl phenyl ether sulfate. Salt (Daiichi Kogyo Seiyaku Co., Ltd. Aqualon HS-10 etc.), α-sulfo-ω- (1-((nonylphenoxy) methyl) -2- (2-propenyloxy) ethoxy) -poly (oxy-1) , 2-ethanediyl) ammonium salt (such as ADEKA Adekaria Soap SE-1025N), polyoxyethylene-1- (allyloxymethyl) alkyl sulfate ammonium salt (Daiichi Kogyo Seiyaku Co., Ltd. Aqualon KH) -10) and the like.

  As a reactive nonionic emulsifier, for example, α- (1-((allyloxy) methyl) -2- (nonylphenoxy) ethyl) -ω-hydroxypoly (oxyethylene) (having a radical polymerization group in the molecule) DENKA Adeka Soap NE-10, etc.), polyoxyethylene alkylpropenyl phenyl ether (Daiichi Kogyo Seiyaku Aqualon RN-20, etc.) and the like.

  As the usage-amount of an emulsifier, it is 0.1-5 mass parts with respect to 100 mass parts of all monomer mixtures, Preferably it is 0.1-4.5 mass parts, More preferably, it is 0.1-4 mass parts. is there. In addition, the upper limit use amount of the non-reactive emulsifier when using the non-reactive emulsifier alone or in combination with the reactive emulsifier is 1 part by mass, preferably 0.7 parts by mass, more preferably 0.4 parts. Part by mass. By setting the use amount of the emulsifier within the above range, a coating film having good stability during polymerization during production of the copolymer latex and excellent in rust prevention can be obtained.

  As the radical polymerization initiator, either an inorganic initiator or an organic initiator can be used. Examples of preferable radical polymerization initiators include peroxodisulfate, peroxide, azobis compound and the like. Specific examples thereof include, for example, potassium peroxodisulfate, sodium peroxodisulfate, ammonium peroxodisulfate, hydrogen peroxide, t-butyl hydroperoxide, benzoyl peroxide, 2,2-azobisbutyronitrile, cumene hydroper Examples include oxides. These can be used alone or in combination of two or more. In addition, a so-called redox polymerization method in which a reducing agent such as acidic sodium sulfite, ascorbic acid or a salt thereof, erythorbic acid or a salt thereof or Rongalite is used in combination with the radical polymerization initiator can also be used.

  The polymerization reaction temperature for producing the copolymer latex used in the present invention is preferably 40 ° C. to 100 ° C., more preferably 45 ° C. to 95 ° C., from the viewpoint of production efficiency and the quality of the obtained copolymer latex. ° C, most preferably 55 ° C to 90 ° C.

  Moreover, in order to raise the polymerization conversion rate of a monomer mixture, the method (providing a cooking process) of raising polymerization reaction temperature can also be employ | adopted after completion | finish of addition of all the monomer mixtures in a polymerization system. The polymerization reaction temperature in such a process is preferably 80 ° C to 100 ° C.

  As the solid content of the copolymer latex at the end of the polymerization reaction (measured by a drying method at 130 ° C. for 1 hour, the solid content in the present invention is measured under these conditions), production efficiency and particle size control during the polymerization reaction are controlled. From the point, Preferably it is 40 mass%-60 mass%, More preferably, it is 43 mass%-57 mass%.

  In the production of the copolymer latex used in the present invention, various conventionally known regulators can be used at the time of the polymerization reaction or at the end of the polymerization reaction, if necessary. For example, a pH adjuster, a chelating agent, etc. can be used.

  Examples of pH adjusters include sodium hydroxide, potassium hydroxide, ammonium hydroxide, sodium bicarbonate, disodium hydrogen phosphate, amines (monoethanolamine, dimethylethanolamine, triethanolamine, triethylamine, etc.). Can be mentioned. In these, it is preferable to use ammonium hydroxide and said amine. These can be used alone or in combination of two or more.

  Examples of the chelating agent include sodium ethylenediaminetetraacetate.

  The solid content of the copolymer latex used in the present invention is preferably 35% by mass to 60% by mass.

  The toluene insoluble content of the copolymer latex used in the present invention is preferably 80% by mass or less, more preferably 75% by mass or less, and most preferably 70% by mass or less. By setting the toluene insoluble content to the above, a coating film excellent in rust prevention, adhesion to the substrate, adhesion to the substrate after repeated heating and cooling, and impact resistance can be obtained.

  The toluene insoluble matter can be controlled by a known method, but it is a practical method to adjust the amount of the chain transfer agent used.

  Although the chain transfer agent is not particularly limited, for example, dimer of nucleus-substituted α-methylstyrene such as α-methylstyrene dimer, n-butyl mercaptan, t-butyl mercaptan, t-dodecyl mercaptan, n-octyl mercaptan, n -Mercaptans such as lauryl mercaptan, disulfides such as tetramethylthuradium disulfide and tetraethylthuradium disulfide, halogenated derivatives such as carbon tetrachloride and carbon tetrabromide, and 2-ethylhexyl thioglycolate. These can be used alone or in combination of two or more. Among these, mercaptans can be preferably used.

  The usage-amount of a chain transfer agent is 0.1-4.0 mass parts normally with respect to 100 mass parts of all the monomer mixtures. By using the chain transfer agent in an amount within the above range, the toluene insoluble content of the copolymer latex used in the present invention can be set within the above range.

  Examples of the method for adding the chain transfer agent include batch addition, batch addition, continuous addition, or a combination thereof.

  The glass transition temperature of the copolymer latex used in the present invention is preferably −40 ° C. to 70 ° C., more preferably −30 to 60 ° C., and most preferably −20 to 50 ° C. By setting the glass transition temperature of the copolymer latex to the above range, a coating film excellent in rust prevention, adhesion to the substrate, adhesion to the substrate after repeated heating and cooling, and impact resistance is obtained. It is done.

  The number average particle diameter of the copolymer latex used in the present invention is preferably 50 nm to 500 nm, more preferably 70 nm to 350 nm, and most preferably 80 nm to 330 nm. By setting the number average particle diameter within the above range, a coating film excellent in rust prevention, adhesion to the substrate, adhesion to the substrate after repeated heating and cooling, and impact resistance can be obtained.

  The number average particle diameter can be adjusted by using an emulsifier used or a conventionally known seed polymerization method. Examples of the seed polymerization method include methods such as an internal seed method in which a seed latex is prepared in a polymerization system and then a polymerization reaction is performed in the same polymerization system, and an external seed method using a separately prepared seed latex.

  It is essential that the water-based rust preventive coating composition of the present invention contains (II) a rust preventive pigment. As the rust preventive pigment, rust preventive pigments that do not contain lead or chromium are preferable from the viewpoint of safety and environment. For example, phosphate metal salts, molybdate metal salts, borate metal salts, cyanamide Anticorrosive pigments such as metal salts are preferred. These can be used alone or in combination of two or more.

  Examples of rust preventive pigments of phosphate metal salts include, for example, orthophosphate metal salts such as zinc orthophosphate, calcium orthophosphate, aluminum orthophosphate, and magnesium orthophosphate, aluminum pyrophosphate, calcium pyrophosphate, tin pyrophosphate, iron pyrophosphate, Metal pyrophosphates such as titanium pyrophosphate, magnesium pyrophosphate and manganese pyrophosphate, metal triphosphate such as iron tripolyphosphate and aluminum tripolyphosphate, metal metaphosphate such as aluminum metaphosphate, calcium metaphosphate, iron metaphosphate and tin metaphosphate Examples of the metal salt include metal phosphate-based layered compounds such as layered titanium phosphate, layered zirconium phosphate, and layered tin phosphate.

  Examples of rust preventive pigments for molybdate-based metal salts include zinc molybdate, calcium molybdate, calcium calcium molybdate, magnesium molybdate, nickel molybdate, cobalt molybdate, strontium molybdate, zinc phosphomolybdate, and phosphomolybdenum. Examples include calcium acid and aluminum phosphomolybdate.

  Examples of the rust preventive pigments of boric acid metal salts include barium borate, barium metaborate, calcium metaborate, and magnesium metaborate.

  Examples of the rust preventive pigment of the cyanamide-based metal salt include cyanamide zinc and cyanamide zinc calcium.

  In addition, zinc oxide or an alkaline earth metal oxide or hydroxide such as magnesium oxide or magnesium hydroxide may be added to the rust preventive pigment to modify the rust preventive pigment.

  Among these rust preventive pigments, metal tripolyphosphate is preferable from the viewpoint of the rust prevention property of the obtained coating film.

  (II) The blending amount of the rust preventive pigment is based on 100 parts by mass of the copolymer latex (solid content) used in the present invention, from the viewpoint of the rust preventive property of the obtained coating film and the storage stability when used as a paint. The amount is preferably 10 to 60 parts by mass, and more preferably 12 to 40 parts by mass.

  As long as the effect of this invention is not impaired, various fillers, various additives, other emulsions, etc. can be added to the aqueous | water-based antirust coating composition of this invention as needed.

  Examples of the filler include inorganic fillers such as calcium carbonate, kaolin clay, talc, diatomaceous earth, silica, mica, aluminum hydroxide, magnesium hydroxide, magnesium carbonate, sepiolite, alumina, titanium oxide, barium sulfate, talc, and bengara. , Glass beads, foam glass beads, volcanic glass hollow bodies, glass materials such as glass fibers, organic fillers such as resin powder, rubber powder, carbon black, and cellulose powder. These can be used alone or in combination of two or more.

  Examples of additives include plasticizers, anti-sagging agents, thickeners, antifoaming agents, dispersants, foaming agents, colloidal stabilizers, preservatives, pH adjusting agents, anti-aging agents, colorants, cross-linking agents, and curing agents. Agents, water retention agents and the like. These can be used alone or in combination of two or more.

  Among the additives, examples of the thickener include polycarboxylates, urethane association type, polyether type, cellulose ether, polyacryl type, polyacrylamide and the like. Examples of the foaming agent include sodium bicarbonate, ammonium carbonate, a nitroso compound, an azo compound, and a sulfonyl hydrazide compound. As a crosslinking agent and a hardening | curing agent, a polyfunctional epoxy compound, an isocyanate type crosslinking agent, a melamine resin, an oxozaline compound etc. can be mentioned, for example.

  Examples of other emulsions include natural rubber latex, acrylic resin latex, vinyl acetate resin latex, urethane resin latex, and epoxy resin latex.

  The water-based anticorrosive coating composition of the present invention can be produced using various conventionally known dispersing devices. Examples of the dispersing device include a butterfly mixer, a planetary mixer, a spiral mixer, a rotary mixer, a kneader, a dissolver, and a paint conditioner.

  Moreover, a conventionally well-known method can be used as a method of apply | coating the water-based antirust coating composition of this invention to a base material. For example, it can apply | coat to a base material using a spatula, a brush, an air spray, an airless spray, a mortar gun, a ricin gun, a roll coating machine etc.

  The water-based anticorrosive coating composition of the present invention can be applied on various metal members such as iron, plated steel plate, stainless steel, and aluminum. A single layer may be applied on these metal members, or a water-based paint generally used can be freely selected and applied as a top coat on the coating obtained by drying after application. May be. Examples of such water-based paints include acrylic paint, urethane paint, UV paint, silicon paint, melamine resin paint, epoxy paint, and fluororesin paint.

  The water-based anticorrosive coating composition of the present invention can be preferably used as a room-temperature dry-type water-based anticorrosive paint, and can also be used as a low-temperature dry type (drying temperature is 40 to 80 ° C.).

  Next, although an Example and a comparative example demonstrate in more detail, this invention is not limited to this. In addition, the measurement and evaluation of each physical property were performed by the following methods.

(1) Toluene-insoluble matter The copolymer latex was dried at 130 ° C. for 30 minutes to obtain a dried product. About 0.5 g of this dried product was precisely weighed, mixed with 30 ml of toluene, shaken for 3 hours, and then filtered through a 325 mesh wire mesh. Next, the residue on the wire mesh was dried at 130 ° C. for 1 hour, and the mass after drying of the residue was determined. The ratio of the mass of the residue after drying to the mass of the original dried product was defined as toluene insoluble matter (% by mass).

(2) Number average particle diameter The number average particle diameter of the copolymer latex was measured by a dynamic light scattering method. As a measuring device, a light scattering photometer (manufactured by CNN Wood, model 6000) was used.

(3) Glass transition temperature The copolymer latex was dried at 130 ° C. for 30 minutes to obtain a dried product. This dried product was set in a differential scanning calorimeter (SII Nano Technology Co., Ltd .: DSC6220) and measured at a temperature elevation rate of 20 ° C./min according to the ASTM method (D3418-97).

(4) Rust prevention property A coating composition containing a copolymer latex and a rust prevention pigment is dried on an iron plate (JIS-G3141, SPCC-SD, 0.8 mm × 70 mm × 150 mm) washed with acetone. The film was applied to a thickness of 60 μm and dried for 3 days under conditions of 23 ° C. and 60% RH. Next, on the dried coating film, JIS-K5660 glossy synthetic resin emulsion paint (trade name: Asuka II, white, manufactured by Kansai Paint Co., Ltd.) was applied so that the dry film thickness was 30 μm. A test piece was obtained by drying for 7 days under conditions of 23 ° C. and 60% RH. Thereafter, a JIS-Z1901 anticorrosive polyvinyl chloride adhesive tape (thickness 0.2 mm) was applied to the coating surface of the test piece up to 10 mm from the end of the test piece, and the entire back surface. The exposed part was only 50 mm × 130 mm of the coating part. Diagonal cuts were made using a knife (blade thickness 0.45 mm) on the exposed coating film portion. At that time, the knife was inserted to the interface between the iron plate and the coating film. Immediately after the cutting, the coating film portion below the diagonal intersection was immersed in a 5% aqueous sodium chloride solution at 23 ° C. for 7 days. After completion of the immersion, the width of occurrence of rust from the cut line (inverted V-shaped) (measured every 5 mm along the cut line and the average value obtained) was measured and evaluated according to the following criteria: . The rust prevention property is preferably ◯ or more. More preferable is ◎.
A: Rust generation width is less than 3 mm
○: Rust generation width is 3 mm to less than 5 mm Δ: Rust generation width is less than 5 mm to less than 10 mm ×: Rust generation width is 10 mm or more

(5) Adhesiveness to base material A coating composition containing a copolymer latex and an anticorrosive pigment on an iron plate as described in the column of (4) Anticorrosive property has a dry film thickness of 30 μm. And then dried for 7 days under conditions of 23 ° C. and 60% RH to obtain a test piece. Thereafter, a 1 mm wide cut was made at equal intervals in the vertical and horizontal directions so that 100 1 mm square coating films could be formed on the coating film portion of the test piece using a knife (blade thickness 0.45 mm). At that time, the knife was inserted to the interface between the iron plate and the coating film. Next, apply JIS-Z1522 cellophane adhesive tape (width 18mm) on 100 pieces of 1mm square paint film, and hold one of the tapes so that the paint film and tape are at right angles within 90 seconds after application. And peeled off momentarily. Thereafter, the state of each 1 mm square coating film was visually observed and evaluated according to the following criteria. The adhesion with the substrate is preferably ◯ or more. More preferable is ◎.
A: All 100 pieces are S1
○: 1 to 5 are S2, 95 to 99 are S1
Δ: 6 to 100 pieces are S2, and 0 to 94 pieces are S1.
×: There is one or more S3. Note) S1: 1 mm square coating film with no peeling of coating film S2: 1 mm square coating film with slight peeling of edge and / or corner coating film S3: Partially or completely 1mm square paint film with paint film peeled off

(6) Adhesiveness with substrate after repeated heating and cooling Repeated heating and cooling test of test piece obtained by the method described in the column of (5) Adhesion with substrate (8 at -5 ° C Time) + (8 hours at 50 ° C.) was 10 cycles). Thereafter, an adhesion measurement test and evaluation of the results were performed by the method described in the column. The adhesion to the substrate after repeated heating and cooling is preferably ◯ or more. More preferably ◎

(7) Impact resistance As described in the column of (4) Rust prevention, except that a coating composition containing a copolymer latex and a rust preventive pigment was applied so that the dry film thickness was 30 μm. The test piece was obtained by the method. Then, this test piece was set in a DuPont-type impact deformation tester (using a shooting die with a radius of 6.35 and a cradle and a weight with a mass of 500 g) so that the coating film side hits the shooting die. Next, the height at which the weight dropped was changed to determine the height at which a crack (hereinafter referred to as “crack”) in which the underlying iron plate could be seen in the coating film was determined and evaluated according to the following criteria. The presence or absence of cracks was confirmed with a microscope (100 to 1000 times). The impact resistance is preferably ◯ or more. More preferable is ◎.
◎: The height at which cracks do not occur is 40 cm or more. ○: The height at which cracks do not occur is 30 cm or more and less than 40 cm. Δ: The height at which cracks do not occur is 20 cm or more but less than 30 cm.

(8) Drying property A coating composition containing a copolymer latex and an anticorrosive pigment on an iron plate as described in the column of (4) Anticorrosive property has a coating amount of 100 g / square meter. Then, it was allowed to stand at 23 ° C. and 60% RH for 20 minutes. Immediately thereafter, the surface of the coating film was lightly touched with a fingertip, the state of the coating film and the fingertip was observed, and evaluated according to the following criteria. The drying property is preferably ◯ or more. More preferable is ◎.
◎: Finger marks do not remain on the coating film ○: Finger marks remain slightly on the coating film △: Finger marks remain on the coating film ×: Fingers become extremely dirty

(9) Storage stability A coating composition containing a copolymer latex immediately after production and a rust-preventive pigment produced using a container with a stirrer is placed in a container with a lid, and the condition is 23 ° C. Left for 2 weeks. Thereafter, the state of the coating composition in the container was observed and judged according to the following criteria. The storage stability is preferably ◯ or more. More preferable is ◎.
(Double-circle): It is the same state as immediately after preparation.
○: There is a sediment at the bottom of the container, but it becomes uniform when stirred.
(Triangle | delta): There exists a sediment in the bottom of a container, and even if it stirs, it will not become a uniform state. And / or there is a slight increase in viscosity.
X: The viscosity is remarkably increased or hardened.

[Production Example A1]
A pressure-resistant reaction vessel was charged with a polymerization initial raw material aqueous solution consisting of 75 parts by mass of water, 0.1 part by mass of sodium dodecylbenzenesulfonate and 0.1 part by mass of itaconic acid, and sufficiently stirred at 80 ° C. Next, a mixture of the monomer mixture and the chain transfer agent shown in Table 1 (hereinafter referred to as a monomer mixture) was continuously added into the pressure-resistant reaction vessel over 6 hours. On the other hand, 10 minutes after the start of the addition of the monomer mixture, the addition of an aqueous mixture consisting of 20 parts by mass of water and 1.1 parts by mass of sodium peroxodisulfate was started to initiate the polymerization reaction. The aqueous mixture was continuously added over 6 hours and 50 minutes.

  After completing the addition of the aqueous mixture, the temperature in the pressure-resistant reaction vessel was raised to 90 ° C. and maintained for 1 hour to complete the polymerization reaction. The polymerization conversion rate of the monomer was 95% or more.

  Thereafter, ammonium hydroxide was added to the obtained copolymer latex to adjust the pH to about 10, and then the residual monomer was removed by steam stripping. Next, the mixture was concentrated by heating, cooled, and filtered through a 325 mesh wire mesh. Finally, the pH was readjusted to 9 by adding ammonium hydroxide, and the solid content was adjusted to 50% by mass to obtain a copolymer latex A1.

[Production Examples A2, A4-A13, B2-B4]
Copolymer latex A2, A4-A13, all in the same procedure as in Production Example A1, except that the initial polymerization raw material aqueous solution, the monomer mixture, the components of the aqueous mixture and the amount thereof were changed as described in Table 1. B2-B4 was obtained.

[Production Example A3]
Polymerization initial raw material aqueous solution consisting of 75 parts by mass of water, 0.1 part by mass of sodium dodecylbenzenesulfonate, and 0.2 parts by mass of polystyrene seed latex (solid content) having a number average particle size of 40 nm is collectively put in a pressure-resistant reaction vessel. The mixture was stirred sufficiently at 80 ° C. Subsequently, the monomer mixture shown in Table 1 was continuously added into the pressure-resistant reaction vessel over 6 hours. On the other hand, 10 minutes after the start of the addition of the monomer mixture, the addition of an aqueous mixture consisting of 20 parts by mass of water and 1.1 parts by mass of sodium peroxodisulfate was started to initiate the polymerization reaction. The aqueous mixture was continuously added over 6 hours and 50 minutes.

  After completing the addition of the aqueous mixture, the temperature in the pressure-resistant reaction vessel was raised to 90 ° C. and maintained for 1 hour to complete the polymerization reaction. The polymerization conversion rate of the monomer was 95% or more.

  Thereafter, ammonium hydroxide was added to the obtained copolymer latex to adjust the pH to about 10, and then the residual monomer was removed by steam stripping. Next, the mixture was concentrated by heating, cooled, and filtered through a 325 mesh wire mesh. Finally, the pH was readjusted to 9 by adding ammonium hydroxide, and the solid content was adjusted to 50% by mass to obtain a copolymer latex A3.

[Production Examples A14, B1, B5]
Copolymer latex A14, B1, B5, all in the same procedure as in Production Example A3, except that the components and amounts of the initial polymerization raw material aqueous solution, monomer mixture, and aqueous mixture were changed as described in Table 1. Got.

[Example 1]
A coating composition having the following composition was uniformly mixed using a copolymer latex A1 in a container with a stirrer.
Copolymer latex A1 (solid content) 100 parts by weight Anticorrosive pigment (P1) * 1 20 parts by weight Filler * 2 65 parts by weight Color pigment * 3 12 parts by weight Dispersant * 4 1.5 parts by weight Thickener * 5 1.5 parts by weight Film-forming aid * 6 2 parts by weight Defoaming agent * 7 0.5 parts by weight Water Added so that the solid content is about 55% by weight

* 1 K-WHITE # 140W (mixture of aluminum dihydrogen triphosphate and zinc oxide, containing 20-30% by mass of zinc oxide, manufactured by Teika Co., Ltd.)
* 2 TALC-MS (Talc, Nippon Talc Co., Ltd.)
* 3 120ED (Bengara, manufactured by Toda Pigment Corporation)
* 4 BYK-154 (Ammonium salt of acrylic copolymer, Big Chemie
(Made by Japan)
* 5 SN thickener 621N (urethane-modified polyether, manufactured by San Nopco)
* 6 CS-12 (2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, manufactured by JNC Corporation)
* 7 Nopco 8034-L (manufactured by San Nopco)

  Subsequently, each physical property was evaluated by the method as described in said (4) to (9) about said coating composition. The results are listed in Table 2. In the coating composition of Example 1, the coating film obtained therefrom is excellent in rust prevention, adhesion to the substrate, adhesion to the substrate after repeated heating and cooling, impact resistance, drying property, storage The coating composition also had good stability.

[Examples 2 to 14]
Except that the copolymer latex was changed from A1 to A2 to A14, the coating composition was prepared and the physical properties were evaluated in the same manner as described in Example 1. The results are listed in Table 2. In the coating compositions of Examples 2 to 14, the coating film obtained therefrom was excellent in rust prevention, adhesion to the substrate, adhesion to the substrate after repeated heating and cooling, impact resistance, and drying properties. The coating composition also had good storage stability.

[Examples 15 to 17]
Example 1 except that the rust preventive pigment was changed to zinc phosphate (P2) in Example 15, calcium molybdate (P3) in Example 16, and barium metaborate (P4) in Example 17. The coating composition was prepared and each physical property was evaluated by the method as described. The results are listed in Table 2. In the coating compositions of Examples 15 to 17, the coating films obtained therefrom were excellent in rust prevention, adhesion to the substrate, adhesion to the substrate after repeated heating and cooling, impact resistance, and drying properties. The coating composition also had good storage stability.

[Examples 18 to 19]
In Example 18, the compounding amount of the rust preventive pigment and the filler is 9 parts by mass, the filler is 76 parts by mass, in Example 19, the rust preventive pigment is 65 parts by mass, and the filler is added. Except for changing to 20 parts by mass, the coating composition was prepared and the physical properties were evaluated in the same manner as described in Example 1. The results are listed in Table 2. In the coating compositions of Examples 18 to 19, the coating films obtained from them were excellent in rust prevention, adhesion to the substrate, adhesion to the substrate after repeated heating and cooling, impact resistance, and drying properties. The coating composition also had good storage stability.

[Comparative Example 1]
Except that the copolymer latex was changed from A1 to B1, the coating composition was prepared and the physical properties were evaluated in the same manner as described in Example 1. The results are listed in Table 2. In the coating composition of Comparative Example 1, the coating film obtained therefrom was inferior in adhesion to the substrate, adhesion to the substrate after repeated heating and cooling, and impact resistance.

[Comparative Example 2]
Except that the copolymer latex was changed from A1 to B2, the coating composition was prepared and the physical properties were evaluated in the same manner as described in Example 1. The results are listed in Table 2. In the coating composition of Comparative Example 2, the coating film obtained therefrom was inferior in rust prevention and impact resistance.

[Comparative Example 3]
Except that the copolymer latex was changed from A1 to B3, the coating composition was prepared and the physical properties were evaluated in the same manner as described in Example 1. The results are listed in Table 2. The coating composition of Comparative Example 3 was a coating composition in which the coating film obtained from the coating composition was inferior in adhesion to the substrate after repeated heating and cooling, and storage stability was inferior.

[Comparative Example 4]
Except that the copolymer latex was changed from A1 to B4, the coating composition was prepared and the physical properties were all evaluated by the method described in Example 1. The results are listed in Table 2. The coating composition of Comparative Example 4 was a coating composition in which the obtained coating film was inferior in rust prevention and poor in drying properties.

[Comparative Example 5]
Except that the copolymer latex was changed from A1 to B5, the coating composition was prepared and the physical properties were evaluated by the same method as described in Example 1. The results are listed in Table 2. In the coating composition of Comparative Example 5, the coating film obtained therefrom was inferior in rust prevention.

[Comparative Example 6]
Except for changing the blending amount of the rust preventive pigment to 0 parts by mass and the blending amount of the filler to 85 parts by mass, the coating composition was prepared and the physical properties were evaluated in the same manner as described in Example 1. went. The results are listed in Table 2. In the coating composition of Comparative Example 6, the coating film obtained therefrom was inferior in rust prevention.

  At the same time, a coating film that sufficiently satisfies various other performances can be obtained, and the water-based anticorrosive coating composition of the present invention having good dryability and storage stability is composed of iron, plated steel sheet, It can be suitably used for imparting rust prevention to various metal members such as stainless steel and aluminum, and has high applicability in various industrial fields.

Claims (6)

(I) (a) 1 to 60 parts by mass of a conjugated diene monomer, (b) a monomer having a hydroxyalkyl group (excluding those corresponding to (a) conjugated diene monomer) 0.5 to 10 parts by mass and a monomer mixture obtained by mixing 30 to 98.5 parts by mass of (c) other monomers copolymerizable therewith (provided that (a) + (b) + (c) = 100 Part of (c) the other monomer, and (c1) the number of parts occupied by the ethylenically unsaturated carboxylic acid monomer is that of the monomers (a), (b) and (c). total per 100 parts by mass, Ri name contains a copolymer latex obtained by emulsion polymerizing the monomer mixture is from 0 to 2.5 parts by weight, and the (II) anticorrosive pigment, wherein (c ) The number of parts occupied by the monobasic ethylenically unsaturated carboxylic acid monomer among other monomers is the monomers (a), (b) and (c). The total 100 parts by weight, the aqueous anticorrosive coating composition characterized in 0 to 0.7 parts by der Rukoto.   Among the other monomers (c), the (c1) ethylenically unsaturated carboxylic acid monomer occupies 100 parts by mass of the monomers (a), (b) and (c). The water-based anticorrosive coating composition according to claim 1, which is 0 to 1.4 parts by mass.   Among the other monomers (c), the (c1) ethylenically unsaturated carboxylic acid monomer occupies 100 parts by mass of the monomers (a), (b) and (c). The water-based anticorrosive paint composition according to claim 1, which is 0 to 0.4 parts by mass.   The blending part number of the (II) rust preventive pigment is 10 to 60 parts by mass with respect to 100 parts by mass of the solid content of the (I) copolymer latex. Water-based anticorrosive coating composition.   5. The aqueous rust preventive coating composition according to claim 1, wherein at least a part of the (II) rust preventive pigment is a tripolyphosphate metal salt. The coated article obtained using the water-based antirust coating composition of any one of Claims 1-5.