Aqueous coating compositions and methods for preparing same

Abstract

The aqueous coating composition contains: (A) an emulsion polymer, the emulsion polymer comprising 5% to 28% by weight of cycloalkyl (meth)acrylate structural units, 0.05% to 10% by weight of phosphorous acid monomer, its salt, or mixture thereof, and zero to 10% by weight of additional ethylenically unsaturated acid monomer, its salt, or mixture thereof, and additional monoethylenically unsaturated nonionic monomer, based on the weight of the emulsion polymer; (B) a specific amount of an aliphatic carboxylic acid of formula (I) HOOC-R1-COOH, (II) R2-COOH, or combinations thereof, their salts, or mixtures thereof; and (C) 2.6% to 10% by weight of an anticorrosive pigment, based on the weight of the aqueous coating composition.

Description

[Technical Field]

[0001] The present invention relates to an aqueous coating composition and a method for preparing the same. [Background technology]

[0002] Introduction Solvent-based coating compositions containing epoxy resins, polyurethanes, or alkyd resins are widely used for metal protective coatings due to their corrosion resistance, mechanical properties, and appearance. Water-based coatings are much less environmentally fraught than solvent-based coatings and are typically used for light- to medium-grade metal protection. Black paints, typically containing carbon black as the primary pigment, are widely used for coating machinery and equipment accessories. Ball mills or sand mills have traditionally been used to produce black paints by dispersing carbon black. Due to its hydrophobic and low density properties, carbon black is more difficult to wet and disperse sufficiently in water using conventional dispersion processes alone than inorganic pigments such as titanium dioxide. To facilitate the wetting and dispersion of carbon black, large amounts of hydrophilic additives are typically added to black paints, but this compromises the corrosion resistance of the resulting paint. Therefore, improving the corrosion resistance of black paints to pass a 240-hour salt spray resistance test is more difficult than for paints of other colors.

[0003] Therefore, there remains a need to provide an aqueous coating composition that has the above-mentioned anti-corrosion properties. Summary of the Invention

[0004] The present invention provides a novel combination of an emulsion polymer, a specific amount of an aliphatic carboxylic acid, and a corrosion-resistant pigment. The aqueous coating composition, including the black paint, demonstrates excellent corrosion resistance, characterized by a maximum creep at scribe of 2 millimeters (mm), after 240 hours of salt spray exposure according to ASTM B117(2011).

[0005] In a first aspect, the present invention provides an aqueous coating composition comprising: (A) an emulsion polymer, based on the weight of the emulsion polymer: an emulsion polymer comprising 5% to 28% by weight of structural units of a cycloalkyl (meth)acrylate, 0.05% to 10% by weight of structural units of a phosphorous acid monomer, its salt, or a mixture thereof, and 0 to 10% by weight of structural units of an additional ethylenically unsaturated acid monomer, its salt, or a mixture thereof, and an additional monoethylenically unsaturated nonionic monomer; (B) an aliphatic carboxylic acid, a salt thereof, or a mixture thereof, wherein the aliphatic carboxylic acid has a structure selected from formula (I), (II), or a combination thereof; HOOC-R1-COOH(I) R2-COOH(II) In the formula, R1 is an alkylene group containing 2 to 16 carbon atoms or a cycloalkylene group containing more than 8 to 16 carbon atoms, and R2 is an alkylene group containing 3 to 17 carbon atoms or a cycloalkylene group containing more than 8 to 17 carbon atoms, an aliphatic carboxylic acid, its salt, or mixture thereof, wherein the aliphatic carboxylic acid, its salt, or mixture thereof is present in an amount to provide a concentration of -OOC-R1-COO- and / or R2-COO- segments of greater than 0.29 wt % and less than 0.7 wt %, based on the weight of the aqueous coating composition; (C) 2.6% by weight to 10% by weight of an anticorrosion pigment, based on the weight of the aqueous coating composition.

[0006] In a second aspect, the present invention is a method for preparing the aqueous coating composition of the first aspect, the method comprising combining an emulsion polymer; an aliphatic carboxylic acid, its salt, or a mixture thereof; and an anticorrosion pigment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Test methods, unless a date is given with the test method number, refer to the test method most recent as of the priority date of this document. Reference to a test method includes both a reference to the testing society and the test method number. The following test method abbreviations and identifiers apply herein: ASTM refers to ASTM International methods.

[0008] Products identified by trade names refer to compositions available under those trade names as of the priority date of this document.

[0009] "And / or" means "and, or alternatively." All ranges are inclusive of the endpoints unless otherwise indicated.

[0010] An "aqueous" composition or dispersion means that the particles are dispersed in an aqueous medium. As used herein, "aqueous medium" means water and 0 to 30% by weight, based on the weight of the medium, of a water-miscible compound such as, for example, an alcohol, a glycol, a glycol ether, a glycol ester, or a mixture thereof.

[0011] A "structural unit," also known as a "polymerized unit," of a specified monomer refers to the remainder of the monomer after polymerization, i.e., the polymerized monomer or the polymerized form of the monomer. For example, the structural unit of methyl methacrylate is:

[0012] [ka] (where the dotted lines represent the points of attachment of the structural units to the polymer backbone).

[0013] Throughout this document, the word fragment "(meth)acrylic" refers to both "methacrylic" and "acrylic." For example, (meth)acrylic acid refers to both methacrylic acid and acrylic acid, and methyl (meth)acrylate refers to both methyl methacrylate and methyl acrylate.

[0014] As used herein, "glass transition temperature" or "T g " can be measured by various techniques, including, for example, differential scanning calorimetry ("DSC") or calculation using the Fox equation. Certain values ​​of T reported herein are calculated using the Fox equation (TGFox, Bull. Am. Physics Soc., Volume 1, Issue No. 3, page 123 (1956)). For example, the T of a copolymer of monomers M1 and M2 g When calculating

[0015]

number

[0016] The aqueous coating composition of the present invention comprises one or more emulsion polymers. The emulsion polymers useful in the present invention comprise one or more cycloalkyl(meth)acrylate structural units. Examples of suitable cycloalkyl(meth)acrylates include cyclohexyl(meth)acrylate, metacyclohexyl(meth)acrylate, isobornyl(meth)acrylate, dihydrodicyclopentadienyl(meth)acrylate, trimethylcyclohexyl(meth)acrylate, t-butyl(meth)cyclohexylacrylate, or a mixture thereof. Preferred cycloalkyl(meth)acrylates include cyclohexyl methacrylate, cyclohexyl acrylate, metacyclohexyl acrylate, or a mixture thereof. The emulsion polymer may contain cycloalkyl (meth)acrylate structural units in a concentration of 5% by weight or more, and can be 6% by weight or more, 7% by weight or more, 8% by weight or more, 9% by weight or more, 10% by weight or more, 11% by weight or more, 12% by weight or more, 13% by weight or more, 14% by weight or more, or even 15% by weight or more, based on the weight of the emulsion polymer, while generally being 28% by weight or less, 27% by weight or less, 26% by weight or less, 25% by weight or less, 24% by weight or less, 23% by weight or less, 22% by weight or less, 21% by weight or less, or even 20% by weight or less. "Weight of emulsion polymer" herein refers to the dry weight of the emulsion polymer.

[0017] Emulsion polymers useful in the present invention may contain structural units of one or more phosphorous acid monomers, salts thereof, or mixtures thereof. The phosphorous acid monomer may have ethylenic unsaturation. The phosphorous acid monomer may be a dihydrogen phosphate ester of an alcohol where the alcohol contains or is substituted with a polymerizable vinyl or olefin group. Phosphorous acid monomers and salts thereof include phosphoalkyl(meth)acrylates such as phosphoethyl(meth)acrylate, phosphopropyl(meth)acrylate, phosphobutyl(meth)acrylate, salts thereof, or mixtures thereof; CH═C(R p1 )-C(O)-O-(R p2 O)q -P(O)(OH)2 (wherein, R p1 =H or CH3, R p2 = alkylene such as an ethylene group, a propylene group, or a combination thereof, q = 1 to 20, for example, SIPOMER PAM-100, SIPOMER PAM-200, SIPOMER PAM-300, and SIPOMER PAM-600 (all available from Solvay); phosphoalkoxy(meth)acrylates such as phosphoethylene glycol (meth)acrylate, phosphodiethylene glycol (meth)acrylate, phosphotriethylene glycol (meth)acrylate, phosphopropylene glycol (meth)acrylate, phosphodipropylene glycol (meth)acrylate, phosphotripropylene glycol (meth)acrylate, salts thereof, or mixtures thereof. Preferred phosphorous acid monomers are selected from phosphoethyl methacrylate (PEM), phosphoethyl acrylate, allyl ether phosphate, or mixtures thereof, and more preferably phosphoethyl methacrylate. The emulsion polymer may comprise structural units of a phosphorous acid monomer, a salt thereof, or a mixture thereof in a concentration of 0.05 wt.% or more, based on the weight of the emulsion polymer, and can be 0.1 wt.% or more, 0.2 wt.% or more, 0.3 wt.% or more, 0.5 wt.% or more, 0.6 wt.% or more, 0.7 wt.% or more, 0.8 wt.% or more, 0.9 wt.% or more, 1.0 wt.% or more, 1.1 wt.% or more, 1.2 wt.% or more, 1.3 wt.% or more, 1.4 wt.% or more, or even 1.5 wt.% or more, while generally 10 wt.% or less, 7 wt.% or less, 5 wt.% or less, 4.5 wt.% or less, 4 wt.% or less, 3.5 wt.% or less, 3.2 wt.% or less, 3 wt.% or less, 2.8 wt.% or less, 2.5 wt.% or less, 2 wt.% or less, or even 1.8 wt.% or less.

[0018] The emulsion polymer useful in the present invention may contain structural units of one or more additional monoethylenically unsaturated acid monomers, their salts, or mixtures thereof, other than phosphorous acid monomers or their salts. The additional ethylenically unsaturated acid monomers may be carboxylic acid monomers, sulfonic acid monomers, and mixtures thereof. The carboxylic acid monomers may be α,β-ethylenically unsaturated carboxylic acids, monomers having acid-forming groups that generate or can subsequently be converted into such acid groups (e.g., anhydrides, (meth)acrylic anhydride, or maleic anhydride), and mixtures thereof. Specific examples of α,β-ethylenically unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, itaconic acid, crotonic acid, fumaric acid, 2-carboxyethyl acrylate, or mixtures thereof. The sulfonic acid monomer may include sodium vinyl sulfonate (SVS), sodium styrene sulfonate (SSS), and acrylamido-methyl-propane sulfonate (AMPS), salts thereof, or mixtures thereof. Preferably, the additional ethylenically unsaturated acid monomer is an α,β-ethylenically unsaturated carboxylic acid, more preferably acrylic acid, methacrylic acid, itaconic acid, or mixtures thereof. The emulsion polymer may contain additional acid monomer and salt structural units in a concentration of zero or more, and can be 0.5% by weight or more, 0.8% by weight or more, 1% by weight or more, 1.2% by weight or more, 1.5% by weight or more, 1.8% by weight or more, or even 2% by weight or more, while generally being 10% by weight or less, and can be 7% by weight or less, 5% by weight or less, 4.5% by weight or less, 4% by weight or less, 3.5% by weight or less, 3% by weight or less, or even 2.5% by weight or less, based on the weight of the emulsion polymer.

[0019] Emulsion polymers useful in the present invention may also contain structural units of one or more monoethylenically unsaturated monomers other than those monomers described above, having one or more functional groups selected from ureido, amide, amino, silane, hydroxyl, acetoacetoxy, acetoacetamide, or combinations thereof. These monoethylenically unsaturated functional monomers include, for example, amino-functional monomers such as dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminopropyl methacrylate, or dimethylaminopropyl acrylate; monomers having an amide functionality such as acrylamide and methacrylamide; vinyltrialkoxysilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, vinyldimethylethoxysilane, and vinylmethyldiethoxysilane, or (meth)acryloxyalkyltrialkoxysilanes such as (meth)acryloxyethyltrimethoxysilane and (meth)acryloxypropyltrimethoxysilane; ureido-functional monomers; hydroxyl-functional monomers such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 3-hydroxybutyl methacrylate; acetoacetoxyethyl methacrylate; acetoacetoxy or acetoacetamido functional monomers including acetoacetoxyalkyl (meth)acrylates such as acetoacetoxyethyl acrylate, acetoacetoxypropyl methacrylate, acetoacetoxybutyl methacrylate, and 2,3-di(acetoacetoxy)propyl methacrylate; allyl acetoacetate; vinyl acetoacetate; acetoacetamidoalkyl (meth)acrylates such as acetoacetamidoethyl methacrylate and acetoacetamidoethyl acrylate; or mixtures thereof. Desirably, the monoethylenically unsaturated functional monomer is a ureido functional monomer.As used herein, the term "ureido-functional monomer" refers to an ethylenically unsaturated compound containing a cyclic ureido group (i.e., an imidazolidin-2-one group). The ureido-functional monomer can include a cyclic ureido-group-containing alkyl ester of (meth)acrylic acid. Examples of suitable ureido-functional monomers include N-(2-methacrylamidoethyl)ethyleneurea, N-(2-methacryloyloxyethyl)ethyleneurea, N-(maleatediethyl)ethyleneurea, or mixtures thereof. A preferred ureido-functional monomer is N-(2-methacryloyloxyethyl)ethyleneurea. The emulsion polymer may comprise structural units of monoethylenically unsaturated functional monomers in a concentration of zero or greater, and can be 0.1% or greater, 0.2% or greater, 0.3% or greater, 0.4% or greater, 0.5% or greater, 0.6% or greater, or even 0.7% or greater, by weight, based on the weight of the emulsion polymer, while generally being 10% or less, 8% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2.5% or less, 2% or less, 1.5% or less, 1.1% or less, 1% or less, 0.9% or less, or even 0.8% or less.

[0020] The emulsion polymers useful in the present invention may contain structural units of one or more additional monoethylenically unsaturated nonionic monomers other than cycloalkyl (meth)acrylates and monoethylenically unsaturated functional monomers. "Nonionic monomer" herein refers to a monomer that does not have an ionic charge at pH=1-14. The additional monoethylenically unsaturated nonionic monomers may be C4-C 24 -C1-C alkyl (meth)acrylates 24 - alkyl (meth)acrylate, styrene, substituted styrene, (meth)acrylonitrile, or mixtures thereof. 24-Alkyl (meth)acrylate refers to an alkyl ester of (meth)acrylic acid containing an alkyl having 1 to 24 carbon atoms. Examples of suitable additional monoethylenically unsaturated nonionic monomers include methyl methacrylate, ethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, butyl (meth)acrylate, tert-butyl (meth)acrylate, lauryl (meth)acrylate, or mixtures thereof. Additional monoethylenically unsaturated nonionic monomers include styrene, substituted styrene, C4-C 24 -alkyl (meth)acrylates, or mixtures thereof. The emulsion polymer may comprise structural units of the additional monoethylenically unsaturated nonionic monomer in a concentration of 42% by weight or more, and may be 45% by weight or more, 50% by weight or more, 55% by weight or more, or even 60% by weight or more, based on the weight of the emulsion polymer, while generally being 94% by weight or less, and may be 90% by weight or less, 85% by weight or less, 80% by weight or less, 75% by weight or less, 70% by weight or less, or even 65% by weight or less.

[0021] The emulsion polymers useful in the present invention may or may not contain structural units of one or more multiethylenically unsaturated monomers, including di-, tri-, tetra-, or higher polyfunctional ethylenically unsaturated monomers other than those mentioned above. Examples of suitable multiethylenically unsaturated monomers include butadiene, allyl (meth)acrylate, divinylbenzene, ethylene glycol dimethacrylate, butylene glycol dimethacrylate, or mixtures thereof. The emulsion polymer may contain structural units of the multiethylenically unsaturated monomer in a concentration of zero to 5%, by weight based on the weight of the emulsion polymer, and may be 3% or less, 2% or less, 1% or less, 0.5% or less, 0.1% or less, or even 0%.

[0022] The emulsion polymers useful in the present invention may contain, by weight based on the weight of the emulsion polymer, 10% to 25% structural units of a cycloalkyl (meth)acrylate, 1.5% to 4% structural units of a phosphorus-containing acid monomer, its salt, or mixtures thereof, and structural units of an additional monoethylenically unsaturated nonionic monomer, and optionally, zero to 3% structural units of a monoethylenically unsaturated functional monomer.

[0023] The total weight concentration of structural units in the emulsion polymer is equal to 100% based on the weight of the emulsion polymer. The types and levels of the above monomers for preparing the emulsion polymer can be selected to provide the emulsion polymer with a glass transition temperature (Tg) suitable for various applications. The Tg of the emulsion polymer, as calculated by the Fox equation, can be zero degrees Celsius (°C) or higher, and can be 5°C or higher, 10°C or higher, 15°C or higher, 20°C or higher, 25°C or higher, or even 30°C or higher, while generally being 60°C or lower, and can be 55°C or lower, 50°C or lower, 47°C or lower, 44°C or lower, or even 40°C or lower.

[0024] The emulsion polymers useful in the present invention may have a number average molecular weight (Mn) of 10,000 grams per mole (g / mol) or greater, and can be 15,000 g / mol or greater, 20,000 g / mol or greater, 25,000 g / mol or greater, 30,000 g / mol or greater, 35,000 g / mol or greater, 40,000 g / mol or greater, 45,000 g / mol or greater, 50,000 g / mol or greater, or even 55,000 g / mol or greater, while generally less than 1000,000 g / mol. The molecular weight of the emulsion polymer may be 800,000 g / mol or less, 600,000 g / mol or less, 400,000 g / mol or less, 300,000 g / mol or less, 200,000 g / mol or less, 150,000 g / mol or less, 120,000 g / mol or less, 100,000 g / mol or less, 80,000 g / mol or less, 70,000 g / mol or less, 65,000 g / mol or less, 60,000 g / mol or less, 55,000 g / mol or less, or even 50,000 g / mol or less. The molecular weight of the emulsion polymer may be measured by gel permeation chromatography (GPC) (further details are provided under GPC analysis).

[0025] Emulsion polymers useful in the present invention can be prepared by emulsion polymerization of a mixture of the monomers described above ("monomer mixture"). The total concentration of monomers for preparing the emulsion polymer is equal to 100% by weight, based on the total weight of the monomers. For each monomer, the weight concentration of the monomer in the monomer mixture relative to the weight of the monomer mixture (i.e., the total weight of the monomers) can be the same as the above-mentioned weight concentration of the structural unit of such monomer in the emulsion polymer relative to the weight of the emulsion polymer. The monomer mixture can be added neat, as an emulsion in water, or in one or more portions or continuously, linearly or non-linearly, over the reaction period to prepare the emulsion polymer. The monomer mixture can be added neat, as an emulsion in water, or in one or more portions or continuously, linearly or non-linearly, over the reaction period to prepare the polymer. Suitable temperatures for the emulsion polymerization process can be below 100°C, in the range of 10 to 99°C, or in the range of 50 to 90°C. One or more surfactants, preferably polymerizable surfactants, can be used in preparing the emulsion polymer. The polymerizable surfactant has the formula (A):

[0026] [ka] (wherein m1 is an integer of 0 to 4, and can be 0, 1, 2, 3, or 4, preferably 1 to 3; n is an integer ranging from 0 to 1,000, 1 to 100, 2 to 60, 3 to 50, or 4 to 40; M represents hydrogen, an alkali metal atom, an alkaline earth metal atom, an ammonium residue, or an alkanolamine residue, and preferably M represents Li + , Na + , K. + , or NH4 +The emulsion polymer may have the structure: The emulsion polymer may comprise polymerizable surfactant structural units in a concentration typically greater than or equal to zero, and may be 0.5% or greater, 0.7% or greater, 0.9% or greater, 1.1% or greater, or even 1.2% or greater, by weight based on the weight of the emulsion polymer, while generally being 10% or less, and may be 7% or less, 5% or less, 4% or less, 3% or less, 2% or less, 1.5% or less, or even 1.3% or less.

[0027] One or more free radical initiators may be used in the polymerization process. The polymerization process may be a thermally initiated or redox initiated emulsion polymerization. Examples of suitable free radical initiators include hydrogen peroxide, t-butyl hydroperoxide, cumene hydroperoxide, ammonium and / or alkali metal persulfates, sodium perborate, superphosphate, and salts thereof; potassium permanganate, and ammonium or alkali metal salts of peroxydisulfate. Free radical initiators may typically be used at levels of 0.01% to 3.0% by weight, based on the total weight of the monomers. Redox systems containing the above initiators combined with a suitable reducing agent may be used in the polymerization process. Examples of suitable reducing agents include sodium formaldehyde sulfoxylate, ascorbic acid, isoascorbic acid, alkali metal and ammonium salts of sulfur-containing acids, such as sodium sulfite, bisulfite, thiosulfate, hydrosulfite, sulfide, hydrogen sulfide, or dithionous acid, formamidine sulfinic acid, acetone bisulfite, glycolic acid, hydroxymethanesulfonic acid, glyoxylic acid hydrate, lactic acid, glyceric acid, malic acid, tartaric acid, and salts of the aforementioned acids. Metal salts of iron, copper, manganese, silver, platinum, vanadium, nickel, chromium, palladium, or cobalt may be used to catalyze the redox reaction. Chelating agents for metals may optionally be used.

[0028] One or more chain transfer agents may be used in the polymerization process to control the molecular weight of the emulsion polymer. Examples of suitable chain transfer agents include 3-mercaptopropionic acid, methyl 3-mercaptopropionate, butyl 3-mercaptopropionate, n-dodecyl mercaptan, n-hexadecanethiol, tert-dodecyl mercaptan, n-octadecanethiol, benzenethiol, alkyl mercaptan azelates, hydroxyl-containing mercaptans such as hydroxyethyl mercaptan, mercaptopropionic acid, and mixtures thereof. The chain transfer agent may be used at a concentration of zero to 2% by weight, based on the total weight of the monomers (i.e., monomer mixture) used to prepare the emulsion polymer, and may be 1.5% by weight or less, 1% by weight or less, 0.5% by weight or less, 0.3% by weight or less, 0.2% by weight or less, or even 0.15% by weight or less.

[0029] After polymerization is complete, the resulting aqueous dispersion can be neutralized with one or more bases as neutralizing agents to a certain pH value, for example, at least 5, and can be 6 to 12, 7 to 10, or 8 to 9. The base can result in partial or complete neutralization of the ionic or potentially ionic groups of the emulsion polymer. Examples of suitable bases include ammonia; alkali metal or alkaline earth metal compounds such as sodium hydroxide, potassium hydroxide, calcium hydroxide, zinc oxide, magnesium oxide, sodium carbonate, and the like; primary, secondary, and tertiary amines such as triethylamine, ethylamine, propylamine, monoisopropylamine, monobutylamine, hexylamine, ethanolamine, diethylamine, dimethylamine, tributylamine, triethanolamine, dimethoxyethylamine, 2-ethoxyethylamine, 3-ethoxypropylamine, dimethylethanolamine, diisopropanolamine, morpholine, ethylenediamine, 2-diethylaminoethylamine, 2,3-diaminopropane, 1,2-propylenediamine, neopentanediamine, dimethylaminopropylamine, hexamethylenediamine, 4,9-dioxadodecane-1,12-diamine, polyethyleneimine, or polyvinylamine; aluminum hydroxide; or mixtures thereof. The emulsion polymer particles in the aqueous dispersion may have a particle size of 50 nanometers (nm) or more, and can be 80 nm or more, or even 90 nm or more, while generally being 500 nm or less, 200 nm or less, or even 150 nm or less. Particle size herein refers to Z-average size and can be measured by a Brookhaven BI-90 Plus Particle Size Analyzer.

[0030] The emulsion polymer may be present in the aqueous coating composition at a concentration of 10% by weight or more, 20% by weight or more, 30% by weight or more, 40% by weight or more, 45% by weight or more, 50% by weight or more, or even 55% by weight or more, based on the weight of the aqueous coating composition, while generally at a concentration of 90% by weight or less, 85% by weight or less, 80% by weight or less, 77% by weight or less, 75% by weight or less, or even 73% by weight or less.

[0031] The aqueous coating composition of the present invention also includes one or more aliphatic carboxylic acids, salts thereof (i.e., neutralized aliphatic carboxylic acids), or mixtures thereof. The carboxylic acids may be saturated. The number of carbon atoms in the aliphatic carboxylic acids is preferably 18 or less to ensure sufficient solubility of the aliphatic carboxylic acids in water. The aliphatic carboxylic acids may have a structure selected from formula (I), (II), or a combination thereof. HOOC-R1-COOH (I) In the formula, R1 is a group having 2 to 16 carbon atoms (C2-C 16 or a cycloalkylene group containing more than 8 carbon atoms to 16 carbon atoms. R1 may contain 2 or more carbon atoms, and can be 4 or more carbon atoms, 5 or more carbon atoms, 6 or more carbon atoms, or even 7 or more carbon atoms, while generally having 16 or fewer carbon atoms, and can be 15 or fewer carbon atoms, 14 or fewer carbon atoms, 13 or fewer carbon atoms, 12 or fewer carbon atoms, or even 11 or fewer carbon atoms. R2-COOH (II) In the formula, R2 is a group having 3 to 17 carbon atoms (C3-C 17 or a cycloalkylene group containing more than 8 carbon atoms to 17 carbon atoms. R2 may have 3 or more carbon atoms, 5 or more carbon atoms, 6 or more carbon atoms, 7 or more carbon atoms, or even 8 or more carbon atoms, while generally having 17 or fewer carbon atoms, and may have 16 or fewer carbon atoms, 15 or fewer carbon atoms, 14 or fewer carbon atoms, 13 or fewer carbon atoms, or even 12 or fewer carbon atoms.

[0032] The aqueous coating composition of the present invention may comprise a mixture of two or more dicarboxylic acids of formula (I) and / or salts thereof, a mixture of two or more monocarboxylic acids of formula (II) and / or salts thereof, a mixture of a dicarboxylic acid of formula (I) and a monocarboxylic acid of formula (II) and / or salts thereof, or a combination thereof. Desirably, the aliphatic carboxylic acid is a dicarboxylic acid of formula (I), which can further improve the anti-blocking properties of the coating composition. Suitable aliphatic carboxylic acids include, for example, sebacic acid (HOOC(CH2)8COOH), dodecanedioic acid (HOOC(CH2)8COOH), and the like. 10 COOH), suberic acid (HOOC(CH2)6COOH), anchoic acid (HOOC(CH2)7COOH), undecanedioic acid (HOOC(CH2)9COOH), stearic acid (HOOC(CH2) 16 The aliphatic carboxylic acid may include sebacic acid, adipic acid (HOOC(CH)COOH), succinic acid (HOOC(CH)COOH), octanoic acid (HC(CH)COOH), decanoic acid (HC(CH)COOH), nonanoic acid (HC(CH)COOH), or mixtures thereof. Desirably, the aliphatic carboxylic acid is sebacic acid.

[0033] The aliphatic carboxylic acids and / or salts thereof useful in the present invention are typically in the form of an aqueous solution. Such aqueous solutions may comprise a reaction mixture of at least one aliphatic carboxylic acid and at least one base. Bases useful for reacting (i.e., neutralizing) the carboxylic acid may include those described above in the emulsion polymer synthesis section, particularly 2-amino-2-methyl-1-propanol, 2-aminoethanol (MEA), 2-dimethylaminoethanol (DMEA), or mixtures thereof. Depending on the type of base used, the resulting salt of the dicarboxylic acid may be an ammonium salt, an alkali metal salt, an amine salt, or a mixture thereof. The amount of base used herein to neutralize the aliphatic carboxylic acid is in an amount that provides a ratio of the weight of base to the total weight of the aliphatic carboxylic acid and base ranging from 0.05 to 0.75, 0.1 to 0.65, 0.2 to 0.55, or 0.3 to 0.5.

[0034] The aliphatic carboxylic acid and / or salt thereof may be present in an amount to provide a segment selected from -OOC-R1-COO-, R2-COO-, or combinations thereof in a concentration of greater than 0.29 wt.% and less than 0.7 wt.%, based on the weight of the aqueous coating composition, and can be 0.30 wt.% or more, 0.31 wt.% or more, 0.32 wt.% or more, 0.33 wt.% or more, 0.34 wt.% or more, 0.35 wt.% or more, 0.36 wt.% or more, 0.37 wt.% or more, 0.38 wt.% or more, 0.39 wt.% or more, or even 0.40 wt.% or more, while generally at a concentration of less than 0.70 wt.%. , 0.69% by weight or less, 0.68% by weight or less, 0.67% by weight or less, 0.66% by weight or less, 0.65% by weight or less, 0.64% by weight or less, 0.63% by weight or less, 0.62% by weight or less, 0.61% by weight or less, 0.60% by weight or less, 0.59% by weight or less, 0.56% by weight or less, 0.55% by weight or less, 0.52% by weight or less, 0.50% by weight or less, 0.49% by weight or less, 0.48% by weight or less, 0.47% by weight or less, 0.46% by weight or less, 0.45% by weight or less, 0.44% by weight or less, 0.43% by weight or less, 0.42% by weight or less, 0.41% by weight or less, or even 0.40% by weight or less. When the aqueous coating composition includes (i) an aliphatic carboxylic acid and / or a salt thereof of Formula (I) and (ii) an aliphatic carboxylic acid and / or a salt thereof of Formula (II), the above concentration refers to the total concentration of -OOC-R1-COO- and R2-COO- segments by weight based on the weight of the aqueous coating composition. Alternatively, when the aqueous coating composition includes only one of (i) and (ii), the above concentration refers to the weight concentration of -OOC-R1-COO- segments or the weight concentration of R2-COO- segments, respectively, relative to the weight of the aqueous coating composition. The -OOC-R1-COO- segments can be derived from dicarboxylic acids and / or salts of dicarboxylic acids of Formula (I). The R2-COO- segments can be derived from monocarboxylic acids and / or salts of monocarboxylic acids of Formula (II).The concentration of -OOC-R1-COO- and / or R2-COO- segments can be determined by liquid chromatography-mass spectrometry (LC-MS), nuclear magnetic resonance (NMR), and / or extraction analysis. Alternatively, the concentration of -OOC-R1-COO- and / or R2-COO- segments can be calculated by the weight of the original unneutralized aliphatic carboxylic acid added relative to the weight of the aqueous coating composition. In the case of an aqueous coating composition containing a salt of an aliphatic carboxylic acid, the weight of the aliphatic carboxylic acid used to form such salt, instead of the weight of the salt, is used to calculate the concentration of -OOC-R1-COO- and / or R2-COO- segments.

[0035] The weight ratio of -OOC-R1-COO- and / or R2-COO- segments to the emulsion polymer can be 0.0114 or more, 0.0116 or more, 0.0118 or more, 0.012 or more, 0.0122 or more, 0.0125 or more, 0.0128 or more, 0.013 or more, 0.0135 or more, 0.0136 or more, 0.0138 or more, 0.014 or more, while generally being 0.024 or less, 0.0235 or less, 0.023 or less, 0.021 or less, 0.020 or less, 0.0195 or less, 0.019 or less, or even 0.0185% or less.

[0036] The aqueous coating composition of the present invention may contain one or more anticorrosion pigments. "Anticorrosion pigment" refers to a pigment that can prevent or delay corrosion of steel by chemical reaction or chelation. Suitable anticorrosion pigments include, for example, zinc phosphate, zinc molybdate, zinc oxide, aluminum tripolyphosphate, zinc molybdenum phosphate, modified zinc phosphate such as calcium-modified zinc phosphate, calcium ion-exchanged amorphous silica, or mixtures thereof. Preferably, the anticorrosion pigment is aluminum tripolyphosphate. The anticorrosion pigment may be present in a concentration of 2.6 wt.% to 10 wt.%, based on the weight of the aqueous coating composition, and may be 2.6 wt.% or more, 2.7 wt.% or more, 2.8 wt.% or more, 2.9 wt.% or more, 3.0 wt.% or more, 3.2 wt.% or more, 3.5 wt.% or more, 3.8 wt.% or more, 4 wt.% or more, 4.2 wt.% or more, 4.5 wt.% or more, 4.8 wt.% or more, 5 wt.% or more, 5.2 wt.% or more, 5.5 wt.% or more, 5.6 wt.% or more, 5.8 wt.% or more, or It may further be 6% or more by weight, and at the same time, generally be 10% or less, such as 9.5% or less, 9% or less, 8.5% or less, 8% or less, 7.6% or less, 7% or less, 6.5% or less, or even 6% or less by weight, such as less than 6% by weight, 5.9% or less, 5.8% or less, 5.7% or less, 5.6% or less, 5.5% or less, 5.4% or less, 5.3% or less, 5.2% or less, or even 5.15% or less by weight. Desirably, the weight ratio of -OOC-R1-COO- and / or R2-COO- segments to the anticorrosion pigment may be 0.17 or less, 0.16 or less, 0.15 or less, 0.14 or less, 0.13 or less, 0.11 or less, or even 0.10 or less.

[0037] The total concentration of the -OOC-R1-COO- segment, the R2-COO- segment, and the anticorrosion pigment can range from 5% to 25% by weight, and can be 5% by weight or more, 6% by weight or more, 7% by weight or more, 8% by weight or more, or even 9% by weight or more, based on the dry weight of the aqueous coating composition, while generally being 25% by weight or less, 24% by weight or less, 23% by weight or less, 22% by weight or less, 21% by weight or less, 20% by weight or less, 19% by weight or less, or even 18% by weight or less.

[0038] The aqueous coating composition of the present invention may or may not contain an additional pigment other than the anticorrosion pigment described above. The term "additional pigment" herein refers to a material that can substantially contribute to the opacity or hiding power of the coating composition. Such materials typically have a refractive index greater than 1.8. Examples of suitable inorganic pigments include titanium dioxide (TiO), iron oxide and iron oxide black, carbon black, zinc sulfide, lemon chrome yellow, Prussian blue, organic pigment yellow, organic pigment red, or mixtures thereof. Carbon black may include acetylene black, channel black, furnace black, lamp black, and thermal black. Preferably, the additional pigment comprises carbon black. The additional pigment, and preferably carbon black, may be present in a concentration of 0.05 wt.% or more, 0.1 wt.% or more, 0.3 wt.% or more, 0.5 wt.% or more, 0.7 wt.% or more, 0.8 wt.% or more, or even 0.9 wt.% or more, based on the weight of the aqueous coating composition, while generally at a concentration of 10 wt.% or less, 8 wt.% or less, 7 wt.% or less, 5 wt.% or less, 4 wt.% or less, or even 3 wt.% or less.

[0039] The aqueous coating composition of the present invention may or may not contain one or more extenders. The term "extender" as used herein refers to a particulate inorganic material having a refractive index of 1.8 or less and greater than 1.3. Examples of suitable extenders include barium sulfate, calcium carbonate, clay, calcium sulfate, aluminosilicates, silicates, zeolites, mica, diatomaceous earth, solid or hollow glass, ceramic beads, nepheline syenite, feldspar, calcined diatomaceous earth, talc (hydrated magnesium silicate), silica, alumina, kaolin, pyrophyllite, perlite, barite, wollastonite, opaque polymers such as ROPAQUE™ Ultra E (ROPAQUE is a trademark of The Dow Chemical Company) available from The Dow Chemical Company, or mixtures thereof. The extender may be present in a concentration of zero or more, 0.5% or more, 1% or more, 1.5% or more, 2% or more, 2.5% or more, or even 3% or more by weight, based on the weight of the aqueous coating composition, while generally at a concentration of 15% or less, 13% or less, 12% or less, 11% or less, 10% or less, or even 9% or less by weight.

[0040] The aqueous coating composition of the present invention may or may not contain one or more flash rust inhibitors. A "flash rust inhibitor" refers to an additive capable of preventing rapid corrosion of a coating immediately after application of the coating composition to a steel substrate. Flash rust inhibitors may include monoacids other than fatty acids of formula (II), alkalis, and / or their salts, which can (i) form a protective thin film with an inhibitory effect by chemical adsorption (chemisorption) on the surface of metals, (ii) form a film by oxide protection of the metal, (iii) react with potentially corrosive components present in aqueous media to form complex products, or (iv) act as a hydrophobic film by a surface adsorption process, providing a barrier against metal dissolution in corrosion reactions. Flash rust inhibitors may include inorganic flash rust inhibitors, organic flash rust inhibitors, or mixtures thereof. Suitable flash rust inhibitors may include, for example, sodium nitrite, sodium molybdate, sodium chromate, sodium phosphate, sodium phosphite, sodium silicate, phosphoric acid, phosphorous acid, magnesium, zinc, or nickel ions (typically in the form of soluble salts of magnesium, zinc, or nickel) that can react with the hydroxyl (—OH) groups of water to form insoluble hydroxides (e.g., Mg(OH)2, Zn(OH)2, or Ni(OH)2) that are deposited on cathodic sites on the metal surface, urea, mercaptobenzothiazole (MBT), benzotriazole, aldehydes, heterocyclic nitrogen compounds, sulfur-containing compounds, acetylenic compounds, ascorbic acid, benzoic acid, benzoates, caffeine, and extracts of natural substances, or mixtures thereof. The concentration of the flash rust inhibitor may range from zero to 2 wt. % based on the dry weight of the aqueous coating composition, and can be 0 or more, 0.01 wt. % or more, 0.03 wt. % or more, 0.04 wt. % or more, 0.05 wt. % or more, 0.06 wt. % or more, 0.07 wt. % or more, or even 0.10 wt. % or more, while generally at concentrations of 2 wt. % or less, 1 wt. % or less, 0.5 wt. % or less, or even 0.4 wt. % or less.

[0041] The aqueous coating composition of the present invention may or may not contain one or more antifoaming agents. "Antifoaming agent," as used herein, refers to a chemical additive that reduces or prevents foam formation. The antifoaming agent may be a silicone-based antifoaming agent, a mineral oil-based antifoaming agent, an ethylene oxide / propylene oxide-based antifoaming agent, an alkyl polyacrylate, or a mixture thereof. Suitable commercially available antifoaming agents may include, for example, TEGO Airex 901 W, TEGO Airex 902 W, and TEGO Foamex 1488 polyether siloxane copolymer emulsions available from TEGO, BYK-022 and BYK-024 silicone antifoaming agents available from BYK, or a mixture thereof. The antifoaming agent may be present in a concentration of zero to 5 wt %, 0.05 to 3 wt %, or 0.1 to 2 wt %, based on the weight of the aqueous coating composition.

[0042] The aqueous coating compositions of the present invention may or may not contain one or more thickeners, also known as “rheology modifiers,” which may include polyvinyl alcohol (PVA), clay materials, acid derivatives, acid copolymers, urethane associate thickeners (UAT), polyether urea polyurethane (PEUPU), polyether polyurethane (PEPU), or mixtures thereof. Examples of suitable thickeners include alkali swellable emulsions (ASE) such as sodium- or ammonium-neutralized acrylic acid polymers, hydrophobically modified alkali swellable emulsions (HASE) such as hydrophobically modified acrylic acid copolymers, associative thickeners such as hydrophobically modified ethoxylated urethane (HEUR), and cellulose thickeners such as methylcellulose ether, hydroxymethylcellulose (HMC), hydroxyethylcellulose (HEC), hydrophobically modified hydroxyethylcellulose (HMHEC), sodium carboxymethylcellulose (SCMC), sodium carboxymethyl 2-hydroxyethylcellulose, 2-hydroxypropylmethylcellulose, 2-hydroxyethylmethylcellulose, 2-hydroxybutylmethylcellulose, 2-hydroxyethylethylcellulose, and 2-hydroxypropylcellulose. Preferably, the thickener is HEUR. The thickener may be present at a concentration of zero to 5 wt%, 0.05 wt% to 3 wt%, or 0.1 wt% to 1 wt%, based on the weight of the aqueous coating composition.

[0043] The aqueous coating composition of the present invention may or may not contain one or more wetting agents. The term "wetting agent" as used herein refers to a chemical additive that reduces the surface tension of the composition, allowing it to spread or penetrate more easily over the surface of a substrate. Wetting agents may be polycarboxylate, anionic, zwitterionic, or nonionic. Suitable commercially available wetting agents include, for example, SURFYNOL 104 and SURFYNOL TG nonionic wetting agents based on actacetylenic diol, available from Evonik; BYK-190, TEGO-750W, and TEGO-755W solutions of block polymers with pigment-affinity groups, available from BYK and Evonik, respectively; BYK-346 and BYK-349 polyether-modified siloxanes, both available from BYK; or mixtures thereof. The wetting agent may be present at a concentration of zero to 5 wt%, 0.05 wt% to 3 wt%, or 0.1 wt% to 2 wt%, based on the weight of the aqueous coating composition.

[0044] The aqueous coating composition of the present invention may or may not contain one or more coalescents. As used herein, the term "coalescent" refers to a slow-evaporating solvent that coalesces polymer particles into a continuous film under ambient conditions. Examples of suitable coalescents include 2-n-butoxyethanol, dipropylene glycol n-butyl ether, propylene glycol n-butyl ether, dipropylene glycol methyl ether, propylene glycol methyl ether, propylene glycol n-propyl ether, diethylene glycol monobutyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, triethylene glycol monobutyl ether, dipropylene glycol n-propyl ether, n-butyl ether, or mixtures thereof. Preferred coalescents include dipropylene glycol n-butyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, n-butyl ether, or mixtures thereof. The coalescent may be present at a concentration of from zero to 15 wt%, from 0.5 wt% to 8 wt%, or from 1 wt% to 7 wt%, based on the weight of the aqueous coating composition.

[0045] The aqueous coating composition of the present invention may include one or more dispersants. The dispersants may be polyacrylic or polymethacrylic acid with various monomers such as styrene, acrylate, or methacrylate esters, or maleic anhydride, diisobutylene, and other hydrophilic or hydrophobic comonomers; salts thereof; or mixtures thereof. The dispersants may be present in concentrations of zero to 5 wt %, 0.05 to 3 wt %, or 0.1 to 1 wt %, based on the weight of the aqueous coating composition.

[0046] In addition to the above-mentioned components, the aqueous coating composition of the present invention may contain any one or combination of the following additives: buffering agents, neutralizing agents, wetting agents, mildewcides, biocides, antiskinning agents, colorants, flow agents, antioxidants, plasticizers, leveling agents, adhesion promoters, and grinding media. These additives may be present in a total concentration of zero to 10 wt %, or 0.1 to 2 wt %, based on the weight of the aqueous coating composition. The aqueous coating composition of the present invention may further contain water in a concentration of, for example, 30 to 90 wt %, 40 to 80 wt %, 50 to 70 wt %, or 55 to 60 wt %, based on the total weight of the aqueous coating composition.

[0047] The present invention also relates to a method for preparing the aqueous coating composition of the present invention, typically by combining the emulsion polymer in aqueous dispersion with an aliphatic carboxylic acid and / or salt thereof, an anticorrosion pigment, and optionally additional pigments, extenders, and other ingredients described above.

[0048] The components in the aqueous coating composition can be mixed in any order to provide the aqueous coating composition. Alternatively, the aliphatic carboxylic acid and / or its salt may be first dissolved in water to form an aqueous solution, which is then mixed with the other components in the aqueous coating composition. By simply blending all the components, the method of the present invention can provide easy processability and application. Any of the optional components described above may be added to the aqueous coating composition during or before mixing to form the aqueous coating composition. The pigment, including the anticorrosion pigment and / or extender, is preferably mixed with a dispersant to form a slurry of the pigment and / or extender. The aliphatic carboxylic acid and / or salt solution is preferably added after the addition of the emulsion polymer.

[0049] The aqueous coating composition of the present invention can be applied to and adhered to a variety of substrates. Examples of suitable substrates include wood, metal, plastic, foam, stone, elastomeric substrates, glass, fabric, concrete, or cementitious substrates. The aqueous coating composition is suitable for a variety of applications, such as marine protective coatings, general industrial finishes, metal protective coatings, automotive coatings, traffic paints, exterior insulation and finish systems (EIFS), wood coatings, coil coatings, plastic coatings, can coatings, architectural coatings, and civil engineering coatings. The aqueous coating composition is particularly suitable for metal protective coatings. The aqueous coating composition can be used as a primer, a topcoat, a one-coat direct-to-metal coating, or in combination with other coatings to form multi-layer coatings.

[0050] The aqueous coating compositions of the present invention can be applied to a substrate by conventional means, including brushing, dipping, rolling, and spraying. Standard spraying techniques and equipment, including air-atomized spraying, air-atomized spraying, airless spraying, high-volume low-pressure spraying, and electrostatic spraying, such as electrostatic bell application, can be used, as can either manual or automated methods. After the aqueous coating composition of the present invention is applied to a substrate, it can be dried to form a film (i.e., coating) at a temperature ranging from 0 to 35°C, or at elevated temperatures, for example, from 35 to 180°C.

[0051] The aqueous coating compositions of the present invention can provide coatings made therefrom with improved corrosion resistance. The present invention also provides a method for improving the corrosion resistance of a substrate susceptible to corrosion, such as a metal. The method includes providing a substrate susceptible to corrosion, applying an aqueous coating composition to the substrate (i.e., coating the coating composition on the substrate), and drying the aqueous coating composition to form a coated substrate. The corrosion resistance is characterized by a maximum creep at scribe of 2 mm, preferably 1.7 mm or less, 1.5 mm or less, 1.2 mm or less, or even 1 mm or less, at a dry film thickness of 40 to 80 micrometers (μm) after at least 240 hours of exposure to salt spray (further details are provided in the Salt Spray Resistance Test section below). The aqueous coating compositions of the present invention can also provide coatings with good block resistance, as indicated by a B-1 or higher rating. The present invention also relates to articles produced by the method. The present invention also relates to processes for preparing coatings. The process may include applying a coating composition to a substrate and drying the applied coating composition to form a coating having the properties defined above. [Example]

[0052] Some embodiments of the present invention will now be described in the following examples, in which all parts and percentages are by weight (wt%) of the aqueous coating composition sample weight unless otherwise specified. Table 1 lists materials for use in the coating composition samples described herein below. TAMOL and ACRYSOL are trademarks of The Dow Chemical Company.

[0053] [Table 1]

[0054] The following standard analytical equipment and methods are used in the examples and in determining the properties and characteristics described herein.

[0055] Salt spray resistance test Coating composition samples were applied to Q panels (cold-rolled steel) using a 150 μm applicator. The resulting coatings were first dried for 5 minutes (min) at 23°C and 50% relative humidity (RH), then dried for 30 hours at 60°C, and finally dried for 7 days at 23°C and 50% RH. An "X"-shaped scribe mark was created by cutting the dried film on the coated panels using a razor blade. These panels were then placed in a salt spray chamber by exposing the as-prepared coated panels to a salt spray environment (5% sodium chloride fog) according to ASTM B117 (2011). After a set period of salt spray, the panels were removed from the salt spray chamber and washed using deionized (DI) water. Blister and rust creep along the scribed marks were then measured. Creep is the width of the maximum blister or rust starting on either side of the scribed mark. The criterion for passing the test is a maximum creep of 2 mm after 240 hours of salt spray testing.

[0056] Block resistance test The coating composition samples were applied to Q panels (cold-rolled steel) using a 150 μm applicator. The resulting coatings were first dried at 23°C and 50% RH for 5 minutes, then at 60°C and 50% RH for 30 hours, and finally at 23°C and 50% RH for 1 day. Two sample panels were stacked on top of each other with a 1 kilogram (kg) weight on top of them (the coating on one panel was in contact with the coating on the other panel). The sample panels with the weight were placed in an oven at 35°C for 4 hours. The 1 kg weight was then removed, and the two stacked panels were separated from each other to evaluate block resistance. The block resistance evaluation was defined by the separation force and the damaged area. A: Separation without force, B: Separation with slight force, C: Separation with weak force using both hands D: Separation with moderate force using both hands, E: Separation with strong force using both hands F: Separation by tool. The numbers indicate the area of ​​damage: 0: No damage, 1: Less than 10%, 2: 10% to 30%, 3: Over 30% to 60%, 4: Over 60% A-0 represents the best and F-4 the worst. Block resistance should be B-1 or better to be acceptable.

[0057] Solid content The solids content of an aqueous dispersion sample is determined by weighing 0.7 ± 0.1 g of sample (the wet weight of the sample is designated "W1"), placing the sample in an aluminum pan (the weight of the aluminum pan is designated "W2") in a 150 °C oven for 25 minutes, then cooling to room temperature (20-25 °C). The aluminum pan containing the dried sample is then weighed, and the total weight is designated "W3." "W3 - W2" refers to the dry weight or solids weight of the sample. The solids content is calculated by (W3 - W2) / W1 × 100%.

[0058] GPC analysis GPC analysis was typically performed on an Agilent 1200. Samples were dissolved in tetrahydrofuran (THF) / formic acid (FA) (5%) at a concentration of 2 milligrams per millimeter (mg / mL), stirred for more than 1 hour, stored at room temperature overnight, and then filtered through a 0.45 μm polytetrafluoroethylene (PTFE) filter before GPC analysis. GPC analysis was performed using the following conditions:

[0059] Columns: one PLgel GUARD column (10 μm, 50 mm x 7.5 mm) in tandem, two Mixed B columns (7.5 mm x 300 mm); column temperature: 40 °C; mobile phase: THF / FA (5%); flow rate: 1.0 mL / min; injection volume: 100 μL; detector: Agilent refractive index detector, 40 °C; and calibration curve: PL polystyrene narrow standards with molecular weights ranging from 2,329,000 to 580 g / mol, using polynomial 3 fitting.

[0060] Synthesis of polymer dispersion 1 (PD-1) Deionized (DI) water (396.8 g), HITENOL™ AR-1025 surfactant (anionic polymerizable surfactant available from DKS Co., Ltd.) (25%, 28.7 g), styrene (ST) (511.5 g) available from Langyuan Chemical Co., Ltd., 2-ethylhexyl acrylate (2-EHA) (436.8 g) available from The Dow Chemical Company, cyclohexyl methacrylate (CHMA) (299.5 g) available from BASF, methacrylic acid (MAA, 37.7 g), phosphoethyl methacrylate (PEM) (28.5 g) available from Solvay, and N-(2-Methacryloyloxyethyl)ethylene urea (N-(2-Methacryloyloxyethyl)ethylene urea) available from Evonik. A stable monomer emulsion was produced by mixing 18.4 g of 50% urea (MEUR) and 2 g of n-dodecyl mercaptan (n-DDM). To 932 g of DI water under a nitrogen atmosphere at 90°C, 30.5 g of AR-1025 surfactant (25%), 0.8 g of ammonia (25%) in 10 g of DI water, 80 g of the monomer emulsion, and 2.5 g of ammonium persulfate (APS) in 15 g of DI water were added, followed by 25 g of DI water to form a reaction mixture. Next, the remaining monomer emulsion, 1.5 g of APS in 90 g of DI water, and 5.4 g of ammonia (25%) in 90 g of DI water were added over 120 minutes at 88°C, followed by 25 g of DI water.At the end of the polymerization, 0.019 g of FeSO4 in 5 g of DI water mixed with 0.024 g of ethylenediamine tetraacetic acid (EDTA) sodium salt in 5 g of DI water, 2.5 g of t-butyl hydroperoxide (t-BHP) dissolved in 25 g of DI water, and 1.1 g of isoascorbic acid (IAA) in 25 g of DI water were added sequentially at 60 °C. Next, 24 g of ammonia in 24 g of DI water was added at 50 °C to obtain an aqueous dispersion. The resulting aqueous dispersion of PD-1 was characterized according to the following test methods and showed a pH of 7.66, an Mn of 48,159 g / mol, a solids content of 42.49%, and a particle size of 81 nm. MAA, IAA, and n-DDM are all available from Sinopharm Chemical Reagent Co., Ltd.

[0061] Coating composition samples IE1 and CE1-6 Preparation of acid / salt solutions: The formulations of aqueous solutions of different acids and 2-dimethylaminoethanol (DMEA) are shown in Table 2. For each formulation, the specific acid, DMEA, and water were mixed and stirred to obtain a clear solution containing the specific acid, its salt, or a mixture thereof. All of the acids and DMEA used were available from Sinopharm Chemical Reagent Co., Ltd.

[0062] Preparation of Mills: Black mill, BaSO4 mill, and anticorrosion pigment mill ("BaSO4+ZP-17 Mill" and "BaSO4+PZ-01 Mill") were prepared based on the formulations in Tables 3 and 4 by mixing the ingredients using a high-speed disperser at speeds of 800 to 3000 revolutions per minute (RPM).

[0063] Using the as-prepared aqueous dispersion of PD-1 (as the binder) and the mill obtained above, coating composition samples were prepared according to the black paint formulation shown in Table 5. The mill was mixed with the binder using a conventional laboratory mixer (mixing speed: 50-1,000 RPM), followed by mixing with the acid / salt solution and other ingredients in a letdown stage. The resulting coating composition samples were evaluated for corrosion resistance according to the test method described in Salt Spray Resistance Test.

[0064] [Table 2]

[0065] [Table 3]

[0066] [Table 4]

[0067] As shown in Table 5, coating composition samples CE1-5 did not contain an anticorrosion pigment. Compared to CE1, which did not contain a sebacic acid / salt solution, increasing the concentration of sebacic acid / salt solution in CE2 and 3 resulted in even worse corrosion resistance. This indicates that sebacic acid / salt solution alone is not useful for improving corrosion resistance in formulations without an anticorrosion pigment. Coating composition samples CE4 and 5, which contained only an anticorrosion pigment, demonstrated poor corrosion resistance, as indicated by creep much wider than 2 mm. In contrast, after 240 hours of salt spray resistance (SSR) testing, coating composition sample IE1, which combined both an anticorrosion pigment and sebacic acid / salt solution, demonstrated significantly better corrosion resistance, as indicated by creep of 2 mm or less along the scribe line, compared to samples CE1-5. Compared to sample CE6, sample IE1, which contained less anticorrosion pigment and more sebacic acid, surprisingly showed narrower corrosion at the scribe line and better corrosion resistance.

[0068] [Table 5] In Tables 5 and 6, "wt% of sebacic acid" is calculated by the weight of sebacic acid (first added) relative to the weight of the coating composition, which can be calculated by multiplying the weight of the sebacic acid / salt solution by 0.205. "wt% of anti-corrosion pigment" is calculated by the weight of the anti-corrosion pigment relative to the weight of the coating composition. The sebacic acid / anti-corrosion pigment ratio is calculated by (weight of sebacic acid / salt solution by 0.205) / weight of the anti-corrosion pigment.

[0069] Coating composition samples (IE2-11 and CE7-9) Water (1), TAMOL 731A, TWIN 4100, TEGO Airex 901W, and BENTONE LT (Table 6) were added sequentially and mixed at 200-1,000 RPM using a high-speed disperser to form a uniform blend. PZ-01 or ZP-17 and BaSO4 were then added and mixed at 2,000-3,000 RPM. After 10 minutes, the dispersion speed was adjusted to 300-1,000 RPM, and water (2) was added to form a grind. The resulting grind and the black mill prepared above were mixed with a binder using a conventional laboratory mixer (mixing speed: 50-1,000 RPM), followed by mixing with the specified acid / salt solution and other ingredients in the letdown stage.

[0070] As shown in Table 6, the coating composition sample containing 2.49 wt.% of the anticorrosion pigment (CE7) exhibited poor corrosion protection properties. The CE8 coating composition sample containing a 0.73% concentration of sebacic acid / salt solution did not meet the creep requirement (i.e., less than 2 mm). The CE9 coating composition sample containing an oxalic acid / salt solution provided poor corrosion protection properties, as indicated by creep along the scribe of more than 2 mm. In contrast, the IE2-IE11 coating composition samples all provided good corrosion resistance, as indicated by creep along the scribe of less than 2 mm, even in the absence of aqueous NaNO2 solution, after 240 hours of salt spray resistance (SSR) testing. It should also be noted that the IE4 sample exhibited better block resistance than the IE11 sample. This indicates that coatings containing dicarboxylic acids have better block resistance than coatings containing monocarboxylic acids.

[0071] [Table 6] The present invention can provide the following aspects. [1] 1. An aqueous coating composition comprising: (A) an emulsion polymer, comprising, based on the weight of said emulsion polymer: 5% by weight to 28% by weight of cycloalkyl(meth)acrylate structural units; 0.05% by weight to 10% by weight of structural units of a phosphorous acid monomer, a salt thereof, or a mixture thereof; zero to 10 weight percent of an additional ethylenically unsaturated acid monomer, its salt, or mixture thereof; an emulsion polymer comprising additional monoethylenically unsaturated nonionic monomeric structural units; (B) an aliphatic carboxylic acid, a salt thereof, or a mixture thereof, wherein the aliphatic carboxylic acid has a structure selected from formula (I), (II), or a combination thereof; HOOC-R 1 -COOH (I) R 2 -COOH (II) In the formula, R 1 is an alkylene group containing 2 to 16 carbon atoms or a cycloalkylene group containing more than 8 to 16 carbon atoms, and R 2 is an alkylene group containing 3 to 17 carbon atoms or a cycloalkylene group containing more than 8 to 17 carbon atoms, The aliphatic carboxylic acid, its salt, or mixture thereof is -OOC-R at a concentration of more than 0.29 wt % to less than 0.7 wt % based on the weight of the aqueous coating composition. 1 -COO- and / or R 2 an aliphatic carboxylic acid, its salt, or mixture thereof, present in an amount to provide a -COO- segment; (C) 2.6 wt % to 10 wt % of an anticorrosion pigment, based on the weight of the aqueous coating composition. [2] The aqueous coating composition according to [1] above, wherein the aliphatic carboxylic acid is selected from sebacic acid, dodecanedioic acid, suberic acid, ancoic acid, undecanedioic acid, stearic acid, adipic acid, succinic acid, octanoic acid, decanoic acid, nonanoic acid, or a mixture thereof. [3] The aqueous coating composition according to the above [1] or [2], wherein the salt of the aliphatic carboxylic acid is an ammonium salt, an alkali metal salt, an amine salt, or a mixture thereof. [4] -OOC-R for the anticorrosion pigment 1 -COO- and / or R 2 The aqueous coating composition according to any one of the above [1] to [3], wherein the weight ratio of the —COO— segment is 0.17 or less. [5] The aqueous coating composition according to any one of the above [1] to [4], wherein the anticorrosion pigment is selected from zinc phosphate, zinc molybdate, zinc oxide, aluminum tripolyphosphate, zinc molybdenum phosphate, calcium-modified zinc phosphate, calcium ion-exchanged amorphous silica, or a mixture thereof. [6] The aqueous coating composition according to any one of [1] to [5] above, comprising 2.8 wt % to 5.7 wt % of the anticorrosion pigment, based on the weight of the aqueous coating composition. [7] The aqueous coating composition according to any one of the above [1] to [6], further comprising carbon black. [8] The aqueous coating composition according to any one of the above [1] to [7], comprising 0.05 wt % to 10 wt % of carbon black, based on the weight of the aqueous coating composition. [9] The aqueous coating composition according to any one of the above [1] to [8], wherein the cycloalkyl (meth)acrylate is selected from cyclohexyl methacrylate, cyclohexyl acrylate, metacyclohexyl acrylate, or a mixture thereof.

[10] The aqueous coating composition according to any one of the above [1] to [9], wherein the phosphorous acid monomer and / or salt thereof is selected from phosphoethyl methacrylate, phosphoethyl acrylate, allyl ether phosphate, or a mixture thereof.

[11] -OOC-R 1 -COO- and / or R 2 The aqueous coating composition according to any one of the above [1] to

[10] , wherein the total concentration of the -COO- segment and the anticorrosion pigment may be in the range of 5 wt % to 25 wt % based on the dry weight of the aqueous coating composition.

[12] The aqueous coating composition according to any one of the above [1] to

[11] , comprising 0 to 2 wt % of a flash rust inhibitor, based on the dry weight of the aqueous coating composition.

[13] A method for preparing the aqueous coating composition according to any one of the above items [1] to

[12] , comprising mixing the emulsion polymer, the aliphatic carboxylic acid, the salt thereof, or a mixture thereof, and the anticorrosion pigment.

Claims

1. 1. An aqueous coating composition comprising: (A) an emulsion polymer, comprising, based on the weight of the emulsion polymer: 5% to 28% by weight of cycloalkyl(meth)acrylate structural units; 0.05% to 10% by weight of structural units of a phosphorous acid monomer, a salt thereof, or a mixture thereof; zero to 10 weight percent of an additional ethylenically unsaturated acid monomer, its salt, or mixture thereof; an emulsion polymer comprising additional monoethylenically unsaturated nonionic monomeric structural units; (B) an aliphatic carboxylic acid, a salt thereof, or a mixture thereof, wherein the aliphatic carboxylic acid has a structure selected from formula (I), (II), or a combination thereof: HOOC-R １ -COOH (I) R ２ -COOH (II) In the formula, R １ is an alkylene group containing 2 to 16 carbon atoms or a cycloalkylene group containing more than 8 to 16 carbon atoms, and R ２ is an alkylene group containing 3 to 17 carbon atoms or a cycloalkylene group containing more than 8 to 17 carbon atoms, The aliphatic carboxylic acid, its salt, or mixture thereof is -OOC-R at a concentration of greater than 0.29 wt % to less than 0.7 wt % based on the weight of the aqueous coating composition. １ -COO- and / or R ２ an aliphatic carboxylic acid, its salt, or mixture thereof, present in an amount providing a —COO— segment; (C) 2.6 wt. % to 10 wt. % of an anticorrosion pigment, based on the weight of the aqueous coating composition; an aqueous coating composition wherein the weight ratio of said —OOC—R 1 —COO— and / or R 2 —COO— segments to said anticorrosion pigment is 0.17 or less;

2. 2. The aqueous coating composition of claim 1, wherein the aliphatic carboxylic acid is selected from sebacic acid, dodecanedioic acid, suberic acid, ancoic acid, undecanedioic acid, stearic acid, adipic acid, succinic acid, octanoic acid, decanoic acid, nonanoic acid, or mixtures thereof.

3. 3. The aqueous coating composition of claim 1 or 2, wherein the salt of the aliphatic carboxylic acid is an ammonium salt, an alkali metal salt, an amine salt, or a mixture thereof.

4. 4. The aqueous coating composition of claim 1, wherein the anticorrosion pigment is selected from zinc phosphate, zinc molybdate, zinc oxide, aluminum tripolyphosphate, zinc molybdenum phosphate, calcium modified zinc phosphate, calcium ion exchanged amorphous silica, or mixtures thereof.

5. 5. The aqueous coating composition of claim 1, comprising 2.8 wt. % to 5.7 wt. % of the anticorrosion pigment, based on the weight of the aqueous coating composition.

6. The aqueous coating composition of any one of claims 1 to 5, further comprising carbon black.

7. 7. The aqueous coating composition of any one of claims 1 to 6, comprising 0.05 to 10 wt. % of carbon black, based on the weight of the aqueous coating composition.

8. The aqueous coating composition of any one of claims 1 to 7, wherein the cycloalkyl (meth)acrylate is selected from cyclohexyl methacrylate, cyclohexyl acrylate, metacyclohexyl acrylate, or mixtures thereof.

9. 9. The aqueous coating composition of any one of claims 1 to 8, wherein the phosphorous acid monomer and / or salt thereof is selected from phosphoethyl methacrylate, phosphoethyl acrylate, allyl ether phosphate, or mixtures thereof.

10. The -OOC-R １ -COO- and / or R ２ 10. The aqueous coating composition according to any one of claims 1 to 9, wherein the total concentration of -COO- segments and the anticorrosion pigment can be in the range of 5 wt% to 25 wt%, based on the dry weight of the aqueous coating composition.

11. 11. The aqueous coating composition of any one of claims 1 to 10, comprising zero to 2 wt. % of a flash rust inhibitor, based on the dry weight of the aqueous coating composition.

12. 12. A method for preparing the aqueous coating composition of any one of claims 1 to 11, comprising mixing the emulsion polymer, the aliphatic carboxylic acid, the salt thereof, or a mixture thereof, and the anticorrosion pigment.

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