Coating composition comprising magnesium oxide and a lithium compound

Abstract

Disclosed herein are coating compositions comprising: (a) a film-forming binder; (b) magnesium oxide; and (c) a lithium compound in an amount of 0.01 wt% to less than 1 wt% by total solids weight, wherein the lithium compound has a solubility constant (Ksp) in water at 25°C of greater than 0.05. Also disclosed are methods for coating a substrate. Also disclosed are coated substrates.

Description

[0001] Cross-referencing

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 619,978, filed January 11, 2024, entitled “Composition Containing Magnesium Oxide Particles and Lithium Salt,” which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure relates to coating compositions comprising magnesium oxide. Background Technology

[0004] Coating compositions containing film-forming binders are widely used in applications such as electrical appliances, automobiles, and aircraft. These coatings may also contain corrosion inhibitors that provide corrosion resistance. Summary of the Invention

[0005] This document discloses a coating composition comprising: (a) a film-forming binder; (b) magnesium oxide; and (c) a lithium compound in an amount of 0.01% to less than 1% by weight of total solids, wherein the lithium compound has a solubility constant (Ksp) in water at 25°C greater than 0.05.

[0006] A method for coating a substrate is also disclosed, the method comprising applying any of the coating compositions disclosed herein to the surface of the substrate to form a first coating.

[0007] A substrate is also disclosed having a coating on its surface formed by any of the coating compositions disclosed herein. Detailed Implementation

[0008] This disclosure relates to a coating composition comprising, or consisting substantially of, or consisting of: (a) a film-forming binder, (b) magnesium oxide, and (c) a lithium compound in an amount of 0.01% by weight to less than 1% by weight of total solids, wherein the lithium compound has a solubility constant (Ksp) in water at 25°C greater than 0.05.

[0009] Film-forming adhesives

[0010] A "film-forming adhesive" is a substance that can form a continuous film on a surface after curing and / or hardening. Film-forming adhesives may contain film-forming resins, such as organic resins. Film-forming adhesives may further contain a curing agent that reacts with the film-forming resin.

[0011] The film-forming resin is not limited and may contain one or more organic polymers, such as acrylic polymers, polyesters, polyurethanes, polyamides, polyethers, polysulfides, polysulfides, polythioesters, polythiols, polyolefins, polyols, polysilanes, polysiloxanes, fluoropolymers, polycarbonates, and / or epoxy resins. Typically, these compounds, which do not need to be polymers, can be prepared by any method known to those skilled in the art. The film-forming resin may contain functional groups, such as carboxylic acid groups, amine groups, epoxy groups, hydroxyl groups, thiol groups, urethane groups, amide groups, urea groups, (meth)acrylate groups, styrene groups, vinyl groups, allyl groups, aldehyde groups, acetoacetate groups, hydrazide groups, cyclic carbonate groups, maleic acid groups, and / or anhydride groups. The functional groups on the film-forming resin may be selected to react with or self-crosslink with the functional groups on the curing agent.

[0012] The film-forming resin may further include inorganic film-forming resins, such as organosilicon resins.

[0013] When present, a curing agent can be selected to be reactive with the film-forming resin. The curing agent may contain molecules or functional groups that can react with reactive groups (such as active hydrogen groups) on the film-forming resin to achieve curing of the coating composition and thus form a coating.

[0014] Examples of suitable curing agents include amino plastics, phenolic plastics, polyisocyanates (including terminal isocyanates), polyepoxides, β-hydroxyalkylamides, polybasic acids, organometallic acid functional materials, polyamines, polyamides, polysulfides, polythiols, polyolefins (such as polyacrylates), polyols, and / or polysilanes. Suitable commercially available amino plastic curing agents include those from ALLNEX, such as CYMEL 303, CYMEL 1130, CYMEL 1156, etc.

[0015] In examples, the coating composition may comprise a film-forming binder comprising an epoxy-containing film-forming resin and a curing agent comprising an amine curing agent. Suitable examples of epoxy-containing film-forming resins include aromatic or aliphatic epoxy resins, such as bisphenol A-based resins, bisphenol A diglycidyl ethers, bisphenol F, glycerol, phenolic varnishes, etc., or epoxy-modified polymers, such as epoxy-modified acrylics. Suitable commercially available epoxy film-forming resins include EPON 828, EPON 862, EPON 1001 and / or EPON 8111, all available from Westlake Epoxy, and DEN431, available from Olin.

[0016] Suitable commercially available amine curing agents include those available under the trade name ANCAMINE, such as ANCAMINE 2432, ANCAMIDE 2569, ANCAMINE 2672, ANCAMINE 2686 and ANCAMINE K-54, all available from Evonik, as well as polyether functional amines, such as those available under the trade name JEFFAMINE, such as JEFFAMINED2000, available from Huntsman Corporation.

[0017] In other examples, the film-forming resin may contain hydroxyl functional groups, such as hydroxyl-functionalized polyesters, hydroxyl-functionalized polyurethanes, hydroxyl-functionalized acrylics, etc.

[0018] The coating composition may contain a film-forming binder in an amount of at least 20% by weight, such as at least 30% by weight, based on the total solid weight of the coating composition. The coating composition may contain a film-forming binder in an amount of no more than 90% by weight, such as no more than 80% by weight, based on the total solid weight of the coating composition. The coating composition may contain a film-forming binder in an amount of 20% to 90% by weight, such as 30% to 80% by weight, based on the total solid weight of the coating composition.

[0019] magnesium oxide

[0020] The coating composition disclosed herein further comprises magnesium oxide (MgO).

[0021] MgO may comprise nanoscale MgO and / or microscale MgO. Particle size may be reported by the manufacturer as average particle size, or optionally, number-average particle size may be determined, for example, by visually examining a micrograph of a transmission electron microscope (“TEM”) image, as described below.

[0022] MgO may comprise micron-sized powder or dispersion thereof with a number average particle size of at least 0.5 micrometers, such as at least 1 micrometer. MgO may comprise micron-sized powder or dispersion thereof with a number average particle size of no more than 50 micrometers, such as no more than 30 micrometers. MgO may comprise micron-sized powder or dispersion thereof with a number average particle size of 0.5 micrometers to 50 micrometers, such as 1 micrometer to 30 micrometers.

[0023] Alternatively or additionally, MgO may comprise nanoscale powder or a dispersion thereof. MgO may comprise nanoscale powder with a number average particle size of at least 10 nm. MgO may comprise nanoscale powder with a number average particle size not exceeding 499 nm, such as not exceeding 100 nm. MgO may comprise nanoscale powder with a number average particle size of 10 nm to 499 nm, such as 10 nm to 100 nm.

[0024] The number-average particle size reported herein can be determined by visually examining the micrographs of transmission electron microscopy (“TEM”) images, measuring the diameter of the particles in the images, and calculating the average primary particle size of the measured particles based on the magnification of the TEM images. Those skilled in the art will understand how to prepare such TEM images and determine the primary particle size based on the magnification. The primary particle size refers to the smallest diameter sphere that completely encapsulates the particle. As used herein, the term “primary particle size” refers to the size of an individual particle, not an agglomeration of two or more individual particles.

[0025] The particle size reported in this article refers to the MgO particle size before incorporation into the coating composition. Various coating preparation methods may cause MgO particles to agglomerate (which may increase the average particle size), or shear or other effects that may reduce the average particle size. MgO particles are commercially available from a variety of sources, such as NANO-MgO from US Research Nanomaterials, Inc. (Texas, USA) and MAGLITE Y from The Hallstar Company (Illinois, USA).

[0026] MgO can comprise ultrafine MgO particles. As used herein, the term "ultrafine" particles refer to particles with a BET specific surface area of ​​at least 10 m² / g (m² / g). 2 / g), such as 30 m 2 / g to 500 m 2 / g, such as 30 m 2 / g to 100 m 2 / g, such as 40m 2 / g to 80 m 2 / g, such as 40 m 2 / g to 60 m 2 / g, such as 80 m 2 / g to 250 m 2 / g of particles. As used herein, “BET specific surface area” refers to the specific surface area determined by nitrogen adsorption according to ASTM D3663-78 based on the Brunauer-Emmett-Teller method described in the Journal of the American Chemical Society, 60, 309 (1938).

[0027] MgO may comprise MgO particles with a calculated equivalent sphere diameter not exceeding 200 nm, such as not exceeding 100 nm, such as 5 nm to 50 nm. As those skilled in the art will understand, the calculated equivalent sphere diameter can be determined from the BET specific surface area according to the following equation:

[0028]

[0029] The shape (or morphology) of MgO particles can vary. For example, MgO particles may comprise particles with a generally spherical morphology and / or MgO particles may be cubic, plate-like, polyhedral, or needle-like (elongated or fibrous). Particles may be completely encapsulated in the polymer gel, completely unencapsulated in the polymer gel, or partially encapsulated in the polymer gel. Partial encapsulation in the polymer gel means that at least some portions of the particles have polymer gel deposited thereon, which may, for example, be covalently bonded to the particles or associated only with the particles.

[0030] MgO can contain one or more different types of MgO particles. For example, MgO can contain MgO nano-sized particles and MgO micro-sized particles.

[0031] MgO is used as a corrosion inhibitor, which can provide at least some corrosion inhibition to the underlying substrate to which the coating composition is applied. As used herein, "corrosion inhibitor" refers to a compound that inhibits the corrosion of metals. The effectiveness of a corrosion inhibitor in a cured coating in preventing corrosion of the substrate to which the coating composition is applied and cured can be demonstrated, for example, by salt spray corrosion testing according to ASTM B117-19. Whether a corrosion inhibitor improves corrosion resistance can be determined by testing the ability of a cured coating containing the corrosion inhibitor to improve corrosion performance, such ability being measured by one or more methods, such as by a reduction in substrate pitting, scratch corrosion, scratch brightening, and / or a reduction in the number and / or size of bubbles present in the coating near the scratches when compared to a similar composition that does not contain a corrosion inhibitor.

[0032] The coating composition may contain magnesium oxide in an amount of at least 6% by weight, such as at least 20% by weight, based on the total solid weight of the coating composition. The coating composition may contain magnesium oxide in an amount of no more than 60% by weight, such as no more than 50% by weight, based on the total solid weight of the coating composition. The coating composition may contain magnesium oxide in an amount of 6% to 60% by weight, such as 20% to 50% by weight, based on the total solid weight of the coating composition.

[0033] lithium compounds

[0034] The disclosed coating composition comprises a lithium compound. The lithium compound may comprise lithium salts, such as lithium hydroxide, lithium sulfate, lithium citrate, lithium acetate, lithium tartrate, and / or lithium nitrate. The lithium compound may comprise lithium oxide, lithium dihydrogen phosphate, and / or lithium oxalate.

[0035] The solubility constant (Ksp) of lithium compounds in water at 25°C can be greater than 0.05, such as at least 1, such as at least 5, such as at least 10, such as at least 20. The Ksp of lithium compounds in water at 25°C can not exceed 1,000, such as not exceeding 500. The Ksp of lithium compounds in water at 25°C can be greater than 0.05 to 1,000, such as 1 to 1,000, such as 5 to 1,000, such as 10 to 1,000, such as 20 to 500. As those skilled in the art will know, the solubility constant can be calculated using the equilibrium concentration of lithium salt ions in a saturated aqueous solution using the following equation:

[0036]

[0037] .

[0038] The Ksp value table can also be found in Chapter 4, “Solubility Product Constants of Inorganic Salts,” of the CRC Handbook of Chemistry and Physics, 105th edition.

[0039] The water solubility of lithium compounds at 20°C can be greater than 3 g / 100 ml, such as greater than 5 g / 100 ml, such as greater than 8 g / 100 ml, such as greater than 10 g / 100 ml, such as 12 g / 100 ml or more.

[0040] The water solubility of lithium compounds at 30°C can be greater than 3 g / 100 ml, such as greater than 5 g / 100 ml, such as greater than 8 g / 100 ml, such as greater than 10 g / 100 ml, such as 12 g / 100 ml or greater.

[0041] Table I provides exemplary Ksp and water solubility values ​​for lithium compounds.

[0042] Table I

[0043]

[0044] The lithium compound may be present in the composition in an amount of at least 0.01% by weight, such as at least 0.05% by weight, based on the total solid weight of the composition. The lithium compound may be present in the composition in an amount of less than 1% by weight, such as not exceeding 0.5% by weight, based on the total solid weight of the composition. The lithium compound may be present in the composition in an amount of 0.01% by weight to less than 1% by weight, such as from 0.05% by weight to 0.5% by weight, based on the total solid weight of the composition.

[0045] The lithium compound may be present in the coating composition in an amount of at least 0.01 vol%, such as at least 0.05 vol%, based on the total solid volume of the coating composition. The lithium compound may be present in the coating composition in an amount of less than 1 vol%, such as not exceeding 0.5 vol%, based on the total solid volume of the coating composition. The lithium compound may be present in the coating composition in an amount of 0.01 vol% to less than 1 vol%, such as 0.05 vol% to 0.5 vol%, based on the total solid volume of the coating composition.

[0046] Optional components

[0047] In addition to MgO and lithium compounds, the coating composition may further contain corrosion inhibitors.

[0048] Additional corrosion inhibitors may include morpholine, monosulfide, disulfide, piperazine, azole, oxazole, thiazole, thiazoline, imidazole, diazole, indoleazine, triazine, tetrazolium and / or toluenetriazole.Non-limiting examples of such additional corrosion inhibitors include, but are not limited to, 4-phenyl-thiomorpholine-3,5-dione, 2-morpholino-4-phenylthiazole, 4-(4-phenyl-2-thiazolyl)-morpholine, 4-(2-thienylmethyl)morpholine, 4-(4-morpholinylacetyl)morpholine, 4-(4-morpholinyldithioalkyl)morpholine, 2,6-dimethyl-4-[(3-methyl-2-thienyl)carbonyl]morpholine, 2,6-dimethyl-4-(2-pyrazinylcarbonyl)morpholine, 4-[(3-methyl-2-thienyl)methyl]morpholine, 4-{[(4-morpholinylmethyl)thioalkyl]methyl}morpholine, 4-[2-(5-ethyl-2-pyridinyl)ethyl]morpholine, Morpholine, 4-[4-(4-morpholinyl)butyl]morpholine, 4-(5-methoxy-2-methyl-4-pyrimidinyl)morpholine, 4-(5-methyl-2-pyrimidinyl)morpholine, 4-[(1,3-dimethyl-1H-pyrazol-5-yl)carbonyl]morpholine, 4-[(1-methyl-1H-pyrazol-5-yl)carbonyl]morpholine, 4-[(3,5-dimethyl-1H-pyrazol-1-yl)carbonyl]morpholine, 4-{[(3-{[2-(4-morpholinyl)-2-oxoethyl]thioalkyl}-1,2,4-thiadiazol-5-yl)thioalkyl]acetyl}morpholine, 4-morpholinopyridine, morpholine-4-dithiocarboxylate morpholine-4-ester (can be Cure) Rite 18 is commercially available from AkroChem, Inc., and tetramethylthiuram monosulfide (available from VANAX™™ at Vanderbilt Chemicals). (Originally acquired from LLC), 1-Boc-(4-benzyl)piperazine, 4-(1-benzylpiperidin-4-yl)piperazine-1-carboxylic acid tert-butyl ester, piperazine-1,4-dithiocarboxylic acid bisphenylamide, 1,4-bis(2-(2-pyridyl)ethyl)piperazine, 1,4-bis-(2-benzyloxy-ethyl)piperazine, 1,4-di(2-furfuryl)piperazine, 1-ethyl-4-(2-thienylsulfonyl)piperazine, 1-isopropyl-4-(2-thienylcarbonyl)piperazine, 1-methyl-4-[(3-methyl-2-thienyl)methyl]piperazine, 1-methyl-4-(3-thienylmethyl)piperazine, 1-isopropyl-4-[(1-methyl-1h-pyrrole- [2-yl)methyl]piperazine, piperazine-1,4-dicarboxylic acid-1,4-di-tert-butyl ester, 1-methyl-benzotriazole, 1-methyl-1,2,3-triazole, 1-phenyl-1,2,3-triazole, 4-methyl-2-phenyl-1,2,3-triazole, 1-benzyl-1,2,3-triazole, 1-benzamido-4-methyl-1,2,3-triazole, 1-methyl-1,2,4-triazole, 1,3-diphenyl-1,2,4-triazole, 1-phenyl-1,2,4-triazole-5-one, 1-methyl-benzotriazole, methyl 1-benzotriazole carboxylate, benzothiazole, 1-phenyl-4-methylimidazole and / or 1-(p-tolyl)-4-methylimidazole.

[0049] Optional additional corrosion inhibitors may comprise at least one heterocycle comprising a ring structure of at least five atoms linked by covalent bonds, wherein the ring comprises at least one heteroatom of carbon and sulfur or nitrogen. The heterocycle may optionally further comprise at least one heteroatom of oxygen or phosphorus. Additional corrosion inhibitors may optionally further comprise at least one other heteroatom of oxygen, nitrogen, sulfur, or phosphorus, or an aromatic ring directly or indirectly bonded to the heterocycle.

[0050] The coating composition may contain other optional additional corrosion inhibitors, such as metal anions that pair with pyridine, pyrrole, and / or imidazole ions via coulometric attraction. As used herein, the term "metal anion" refers to metal compounds of molybdenum, tungsten, vanadium, zirconium, and / or chromium.

[0051] Other corrosion inhibitors may include lithium-containing compounds such as lithium silicate with Ksp less than 0.05, rare earth corrosion inhibitors such as yttrium and cerium-containing compounds, and / or conventional corrosion inhibitor particles such as, but not limited to, iron phosphate, zinc phosphate such as zinc hydroxyphosphate (available from Elementis via NALZIN), calcium ion-exchanged silica (available from Gare & Co. via SHIELDEX AC3 and / or SHIELDEX C30), colloidal silica, synthetic amorphous silica, and molybdates such as calcium molybdate, zinc molybdate, barium molybdate, and / or strontium molybdate.

[0052] The coating composition may contain additional corrosion inhibitors in an amount of at least 0.05% by weight, such as at least 0.1% by weight, based on the total solid weight of the coating composition. The coating composition may contain additional corrosion inhibitors in an amount of no more than 5% by weight, such as no more than 4% by weight, based on the total solid weight of the coating composition. The coating composition may contain additional corrosion inhibitors in an amount of 0.05% to 5% by weight, such as 0.1% to 4% by weight, based on the total solid weight of the coating composition.

[0053] Alternatively, the coating composition may be substantially free of, essentially free of, or completely free of corrosion inhibitors, except for MgO and lithium compounds.

[0054] The coating composition may contain other components commonly used in such compositions, examples of which include additional polymers, water, solvents such as organic solvents, colorants, fillers including clay, inorganic minerals, abrasion-resistant particles, antioxidants, hindered amine light stabilizers, UV light absorbers and stabilizers, surfactants, flow and surface control agents, thixotropic agents, reactive diluents, desiccants, catalysts, reaction inhibitors, adhesion promoters such as acids and acid derivatives, phosphorylated epoxy resins, silanes such as epoxy silanes or amino silanes, and other conventional additives known to those skilled in the art. As used herein, "colorant" means any substance that imparts color and / or other opacity and / or other visual effects to the composition.

[0055] The coating composition may be substantially free of, essentially free of, or completely free of molybdenum. The coating composition may be substantially free of, essentially free of, or completely free of molybdenum-containing lithium salts, such as lithium molybdate.

[0056] The coating composition may be substantially free of, essentially free of, or completely free of hexavalent chromium.

[0057] The coating composition may be substantially free of, essentially free of or completely free of zinc salts of 2,5-dimercapto-1,3,4-thiadiazole (DMTD).

[0058] Compositions and coatings

[0059] The coating compositions disclosed herein may be liquid coating compositions under ambient conditions, such as solvent-based coating compositions (where more than 50% of the total solvent is an organic solvent) or water-based coating compositions (where 50% or more of the total solvent is water), or may be powder coating compositions.

[0060] The coating compositions disclosed herein can be thermosetting or thermoplastic. "Thermosetting" compositions harden irreversibly upon curing. "Thermoplastic" compositions harden reversibly upon curing. That is, after curing, a thermoplastic composition can be heated to soften the cured composition and then cooled to re-harden.

[0061] The compositions of the present invention may be one-component (“1K”) or multi-component compositions such as two-component (“2K”) or more. As used herein, a “one-component” composition is one in which all components remain in the same container after manufacture, during storage, etc. A 1K composition may be applied to a substrate and cured by any conventional method, such as by heating, forced ventilation, etc. As used herein, a “multi-component” composition is one in which all components remain separate until just before application. For example, the compositions of the present invention may be packaged as a 2K system, wherein the resin component is in the first component (A) and the curing agent component is in the second component (B). All other components used in the coating composition may be present in component (A), component (B), and / or a third or higher component (C).

[0062] The coating compositions disclosed herein can be prepared using any suitable method, such as manual stirring, or air or electric mixing, such as using a paddle stirrer, or static mixing, magnetic stirring rod, etc. The coating compositions of the present invention can be formulated as primers, base coats, topcoats, sealants, fillers, and / or adhesives.

[0063] This document further discloses coatings deposited by any of the coating compositions disclosed herein. Upon curing, the coating can have any desired dry film thickness (“DFT”). Coatings formed by any of the coating compositions disclosed herein can impart corrosion inhibition to metallic substrates. For example, coatings cured to a DFT of 0.5 mils to 10 mils impart excellent corrosion resistance and adhesion. Coatings deposited by one of the coating compositions disclosed herein are combined with coatings containing MgO or containing K. sp Coating compositions containing greater than 0.05% lithium compound (0.01% to less than 1% by weight of the total solids of the coating composition) imparted improved corrosion resistance while maintaining pencil hardness and adhesion properties. This was a surprising and unexpected result. It was also surprising to find that with increasing lithium compound solubility, even lower amounts of lithium compound were required to achieve the desired adhesion and corrosion resistance.

[0064] The coatings formed from the coating compositions disclosed herein exhibit the following characteristics:

[0065] (a) No pitting from the debonding corrosion pitting test;

[0066] (b) 4H pencil hardness rating;

[0067] (c) Pencil hardness rating after 4 hours of soaking in SKYDROL;

[0068] (d) Dry adhesion rating of 5B;

[0069] (e) 5B wet adhesion rating;

[0070] (f) Scribing corrosion rating less than 20; scribing gloss rating at least 30; less than 4 scribing bubbles; 0 surface bubbles; and / or maximum scribing bubble size less than 3.0 mm after 1000 hours of salt spray testing on bare 2024-T3 aluminum panels according to ASTM B117-19.

[0071] (g) Scribing corrosion rating less than 15; scribing gloss rating of 70 or greater; 10 or fewer scribing bubbles; 8 or fewer surface bubbles; and / or a maximum scribing bubble size of 3.5 or less after 1,000 hours of salt spray testing on covered 2024-T3 aluminum panels according to ASTM B117-19.

[0072] (h) A scribing corrosion rating of 20 or less; a scribing gloss rating of 0; one or fewer scribing bubbles; zero surface bubbles; and / or a maximum scribing bubble size of 3.8 or less after 3000 hours of salt spray testing on exposed 2024-T3 aluminum panels according to ASTM B117-19; and / or

[0073] (i) 40 or less of a scribing corrosion rating; 0 of a scribing gloss rating; 5 or fewer scribing bubbles; 0 of a surface bubble; and / or a maximum scribing bubble size of less than 6 after 3,000 hours of salt spray testing on a covered 2024-T3 aluminum panel according to ASTM B117-19.

[0074] method

[0075] This disclosure also relates to a method for coating a substrate, the method comprising applying a first coating composition comprising a coating composition of the present disclosure to at least a portion of the substrate to form a first coating, and optionally applying one or more additional coatings to at least a portion of the first coating, wherein the one or more additional coatings are applied by a coating composition that is the same as or different from the coating composition of the present disclosure and / or the one or more additional coatings are applied by a coating composition comprising a silicone-modified polyester coating composition, a fluoropolymer coating composition and / or a polyurethane coating composition.

[0076] One or more additional coatings may be applied to the uncured coating composition of this disclosure, the at least partially cured coating composition of this disclosure, or the fully cured coating composition of this disclosure.

[0077] After application to a substrate, the composition can be cured. For example, before applying additional coatings of the same or different type, the composition can be cured at room temperature for any desired period of time sufficient for at least partial curing on the substrate, such as 1 to 2 hours. In another example, the composition can be fully cured at room temperature for any desired period of time, such as two weeks. The composition can be cured under ambient or slightly heated conditions to form a coating on the substrate surface. The coating can be, for example, a primer, base coat, topcoat, sealant, filler, or adhesive.

[0078] This disclosure further relates to a method for forming a coating on at least a portion of a substrate using a coating composition of this disclosure, the method comprising depositing the coating composition onto the substrate. The coating composition may be deposited onto or “applied to” the substrate by any suitable method known to those skilled in the art. Examples include roll coating, spray coating (such as electrostatic spraying), flow coating, spin coating, curtain coating, brush coating, roller coating, dip coating, or by using a fluidized bed.

[0079] Once the coating composition is deposited on the substrate, it can be dried or cured by any suitable method. Examples of such suitable curing techniques include curing under ambient conditions, curing at high temperatures, and / or exposure to photochemical radiation. As used herein, “ambient” conditions refer to room temperature (20°C ± 5°C) and humidity conditions (20% to 80% relative humidity). As used herein, “high” temperature refers to a temperature of 30°C or higher. High temperatures can be achieved by baking in a thermal oven, induction heating, and / or infrared heating. The composition can be fully cured at room temperature for any desired period of time, such as two weeks. Upon curing, a coating is formed on the substrate.

[0080] Additive manufacturing

[0081] The coating compositions disclosed herein can be used in any suitable additive manufacturing technology, such as three-dimensional (3D) printing, extrusion, jetting, and binder jetting. Any suitable mixing, conveying, and 3D printing equipment known to those skilled in the art can be used.

[0082] The methods provided in this disclosure include printing a composition onto a manufactured part. The methods provided in this disclosure include directly printing and / or manufacturing parts or articles of interest using additive manufacturing processes such as 3D printing. The entire part may be formed from one of the compositions disclosed herein, and / or one or more surfaces of the part may be formed from the compositions provided in this disclosure. Additionally, internal regions of the part may be formed from the compositions provided in this disclosure.

[0083] Substrate

[0084] This disclosure further relates to substrates at least partially coated with a coating deposited by any of the coating compositions disclosed herein. Suitable substrates include metallic substrates such as flexible and rigid metallic substrates, metallic alloy substrates, and / or metallized substrates such as nickel-plated plastics. Additionally, substrates may include non-metallic substrates, such as polymeric materials, such as plastics (including filled and unfilled thermoplastic or thermosetting materials), and / or composite materials, such as, for example, plastics, glass fibers, and / or materials containing carbon fibers and / or conductive carbon. Substrates may include any combination of two or more materials. For example, a substrate may include two different metals, or metals and metal alloys, or metals and metal alloys and one or more composite materials.

[0085] The coated substrate may include three-dimensional components formed by additive manufacturing processes, such as three-dimensional molded composite materials.

[0086] Metals or metal alloys may include, for example, cold-rolled steel, hot-rolled steel, steel coated with zinc metal, zinc compounds, or zinc alloys, such as electro-galvanized steel, hot-dip galvanized steel, galvanized annealed steel, galvanized steel, nickel-plated steel, steel plated with zinc alloys, and stainless steel, such as martensitic, duplex, ferritic, austenitic, and / or precipitation-hardening stainless steel. Steel substrates coated with a weldable organic coating rich in zinc or iron phosphide (such as cold-rolled steel or any of the steel substrates listed above) are also suitable for this disclosure. Such weldable coating compositions are disclosed in U.S. Patent Nos. 4,157,924 and 4,186,036, which are incorporated herein by reference. Substrates may include aluminum, aluminum alloys, zinc-aluminum alloys (such as GALFAN, GALVALUME), aluminized steel, and steel substrates coated with aluminized alloys. Non-limiting examples of aluminum alloys include the 1000, 2000, 3000, 4000, 5000, 6000, or 7000 series, such as 2024, 2024-T3, 7075, and 7075-T6, as well as clad aluminum alloys, such as the 2024-T3 cladding, and cast aluminum alloys, such as, for example, the A356 series. The substrate may include magnesium alloys. Non-limiting examples of suitable magnesium alloys include magnesium alloys of the AZ31B, AZ91C, AM60B, or EV31A series. The substrate used in this disclosure may also include other suitable non-ferrous metals (such as titanium or copper) and alloys of these materials.

[0087] The substrate may include multi-metal articles. As used herein, the term "multi-metal article" means (1) an article having at least one surface containing a first metal and at least one surface containing a second metal different from the first metal, (2) a first article having at least one surface containing a first metal and a second article having at least one surface containing a second metal different from the first metal, or (3) both (1) and (2). The substrate may include surfaces or components of different substrates that are adjacent or connected together, such as, for example, an electrical coupling assembly.

[0088] The substrate to which the coating is deposited by the coating composition of this disclosure may be uncoated prior to the coating being deposited thereon.

[0089] A substrate comprising a coating deposited by the coating composition of this disclosure may include one or more additional layers above and / or below the layer; these multiple layers are referred to herein as a “multilayer coating system” or a “coating stack.” Additional layers may include an aluminum cladding layer, an anodized layer, a conversion coating, a non-chromate treatment, and / or a pretreatment layer. Pretreatment layers may include, for example, pretreatment layers such as those described in U.S. Patent Nos. 4,793,867 and 5,588,989 (incorporated herein by reference); zirconium-containing pretreatment solutions such as those described in U.S. Patent Nos. 7,749,368 and 8,673,091 (incorporated herein by reference); phosphate-containing pretreatment solutions (e.g., zinc phosphate-containing pretreatment solutions); and / or sol-gels such as those comprising alkoxy-silanes, alkoxy-zirconates, and / or alkoxy-titaniumates. The coating composition of this disclosure may be applied to at least a portion of the pretreated layer; one or more additional coatings may be applied to at least a portion of the coating. Additional coatings may include primers, base coats, colored coatings, single coats, clear coats, and / or topcoats. Suitable additional coatings include any of those known in the art and may be water-based, solvent-based, in the form of solid particles (i.e., powder coating compositions), or in the form of powder pastes. These additional coatings may cure independently or optionally be applied and cured simultaneously in a “wet-on-wet” manner. As used herein, “wet-on-wet” refers to a process in which a coating (e.g., a clear coat) is applied over a substantially uncured different coating (e.g., a colored coat), and both coatings are cured simultaneously. The different layers in a coating stack may contain components that impart the desired properties, visual effects, and / or color effects to the coating, such as corrosion inhibitors; conductive agents, such as graphene, conductive carbon black, conductive polymers, or conductive additives; pigments, such as those described in U.S. Patent No. 10,844,256 8:18-43 (the portion of which is incorporated herein by reference), or other colored pigments, etc.

[0090] The substrate can be new (i.e. newly constructed or manufactured) or refurbished, in the case of refurbishing or repairing components of a car or aircraft.

[0091] The substrate can be in any form, such as sheet, foil, laminated foil, pad, prefabricated part, assembly, and / or article. The substrate can be cylindrical, such as a pipe, including, for example, cast iron pipe. The substrate can also include a conductive or non-conductive substrate at least partially coated with a conductive coating. The conductive coating can include conductive agents, such as, for example, graphene, conductive carbon black, conductive polymers, and / or conductive additives.

[0092] The substrate may optionally undergo other treatments prior to coating. For example, the substrate may be cleaned, deoxidized, anodized, pickled, subjected to plasma treatment, laser treatment, or ion vapor deposition (IVD). The substrate may be sanded, such as by wet sanding or dry sanding with a pad (such as a 3M SCOTCH-BRITE pad).

[0093] The applications of the compositions disclosed herein are not limited. The coating compositions disclosed herein are suitable for a wide range of industrial or transportation applications, including electrical, coil, automotive, commercial transportation, rail, marine, and / or aerospace applications. Suitable substrates for use in this disclosure include those used in sheet or roll form, or those used in the assembly of appliances or vehicle bodies (such as doors, body panels, trunk lids, top panels, hoods, tops and / or longitudinal beams, rivets, landing gear components, and / or skins used on aircraft), vehicle frames, vehicle components, motorcycles, wheels, and industrial structures and components. As used herein, “vehicle” or variations thereof include all types of aircraft, spacecraft, watercraft, and landcraft. Vehicles can be aerospace vehicles, including aircraft such as airplanes, including private aircraft, and small, medium, or large commercial passenger aircraft, cargo aircraft, civil and military aircraft; helicopters, including private, commercial, and military helicopters; or rockets and other spacecraft. Vehicles can include land vehicles such as tanks, armored vehicles, trailers, automobiles, trucks, buses, vans, construction vehicles, golf carts, motorcycles, bicycles, trains, and railway vehicles. Vehicles can also include water vehicles such as, for example, ships, small boats, and hovercraft. The coating composition can be used to coat surfaces and components thereof. Components can comprise multiple surfaces. Components can include a portion of a larger component, assembly, or device. A portion of a component can be coated with the coating composition disclosed herein, or the entire component can be coated. "Aircraft component" means any component used on any aircraft, whether internal or external, and made from any substrate.

[0094] definition

[0095] For the purposes of this detailed description, it should be understood that alternative variations and sequences of steps may be taken in this disclosure, except where expressly stated otherwise.

[0096] The numerical values ​​presented in the specific examples are reported as accurately as possible. However, any numerical value inherently contains some error due to the standard deviation present in its corresponding test measurement results.

[0097] Furthermore, it should be understood that any numerical range described herein is intended to include all subranges included therein. For example, the range “1 to 10” is intended to include all subranges between (and including) the stated minimum value of 1 and the stated maximum value of 10, that is, a minimum value equal to or greater than 1 and a maximum value equal to or less than 10.

[0098] As used herein, the terms “including,” “containing,” and similar terms are understood in the context of this application to be synonymous with “comprising,” and are therefore open-ended and do not exclude the presence of additional undescribed or unstated elements, materials, components, or method steps. As used herein, “consisting of” is understood in the context of this application to exclude the presence of any unspecified elements, components, or method steps. As used herein, “generally consisting of” is understood in the context of this application to include the specified elements, materials, components, or method steps “as well as elements, materials, components, or method steps that do not materially affect the essential and novel characteristics of the described content.”

[0099] In addition, in this application, unless otherwise expressly stated, the use of “or” means “and / or”, even if “and / or” can be explicitly used in certain situations.

[0100] As used herein, the terms “on,” “to,” “applied on,” “applied to,” “formed on,” “deposited on,” “deposited on,” etc., mean to form, cover, deposit, or be disposed on a substrate surface, but not necessarily in contact with the substrate surface. For example, a composition “applied to” a substrate surface does not exclude the presence of one or more other intermediate coatings of the same or different compositions located between the composition and the substrate surface.

[0101] As used herein, "coating composition" refers to a composition, such as a solution, mixture, or dispersion, capable of producing a coating on a portion of the surface of a substrate.

[0102] As used in this article, "coating" includes films, layers, etc.

[0103] As used herein, “polymer” refers to prepolymers, oligomers, homopolymers, and copolymers.

[0104] As used herein, the terms “cured,” “cured,” “hardened,” etc., refer to the ability of at least a portion of polymerizable and / or crosslinkable components to react. Furthermore, curing of the coating composition occurs when the composition is subjected to curing conditions (e.g., ambient temperature, elevated temperature, photochemical radiation, etc.), thereby causing at least a portion of the reactive functional groups on the components of the coating composition to react, and resulting in the formation of a coating that is at least partially crosslinked and at least partially cured.

[0105] As used herein, “substantially free” means that the particular material is not intentionally added to the mixture or composition, and that the particular material is present only as a trace impurity of less than 0.001% by weight, based on the total solids weight of the mixture or composition. As used herein, unless otherwise stated, the term “substantially free” means that the particular material is present only in an amount of less than 0.0001% by weight, based on the total solids weight of the mixture or composition. As used herein, unless otherwise indicated, the term “completely free” means that the mixture or composition does not contain the particular material, i.e., the mixture or composition contains 0% of such material by solids weight.

[0106] aspect

[0107] In view of the foregoing description, this disclosure relates to, but is not limited to, aspects 1 through 67.

[0108] Aspect 1. A coating composition comprising:

[0109] (a) Film-forming adhesives;

[0110] (b) Magnesium oxide; and

[0111] (c) Lithium compounds in amounts from 0.01% by weight to less than 1% by weight, based on total solid weight;

[0112] The lithium compound has a solubility constant (Ksp) in water at 25°C greater than 0.05.

[0113] Aspect 2. The coating composition according to Aspect 1, wherein the film-forming binder comprises a compound containing a carboxylic acid ester functional group, an amine functional group, an epoxide functional group, a hydroxyl functional group, a thiol functional group, a urethane functional group, an amide functional group, a urea functional group, a (meth)acrylate functional group, a styrene functional group, a vinyl functional group, an allyl functional group, an aldehyde functional group, an acetoacetate functional group, an acylhydrazine functional group, a cyclic carbonate functional group, a maleic acid functional group, and / or an anhydride functional group.

[0114] Aspect 3. The coating composition according to aspect 1 or aspect 2, wherein the film-forming adhesive further comprises a curing agent.

[0115] Aspect 4. The coating composition according to aspect 3, wherein the curing agent comprises amino plastics, phenolic plastics, polyisocyanates, terminated isocyanates, polyepoxides, β-hydroxyalkylamides, polybasic acids, organometallic acid functional materials, polyamines, polyamides, polysulfides, polythiols, polyolefins such as poly(meth)acrylates, polyols and / or polysilanes.

[0116] Aspect 5. The coating composition according to any one of the preceding aspects, comprising at least 20% by weight, such as at least 30% by weight, of the film-forming binder based on the total solid weight of the coating composition.

[0117] Aspect 6. The coating composition according to any one of the preceding aspects, comprising, based on the total solid weight of the coating composition, an amount not exceeding 90% by weight, such as not exceeding 80% by weight, of the film-forming binder.

[0118] Aspect 7. The coating composition according to any one of the preceding aspects, comprising, based on the total solid weight of the coating composition, an amount of the film-forming adhesive, such as 30% to 80% by weight.

[0119] Aspect 8. The coating composition according to any one of the preceding aspects, wherein the magnesium oxide comprises nano-sized magnesium oxide and / or micro-sized magnesium oxide.

[0120] Aspect 9. The coating composition according to any one of the preceding aspects, wherein the magnesium oxide has a number-average particle size of at least 0.5 micrometers, such as at least 1 micrometer, as measured using a transmission electron microscope.

[0121] Aspect 10. The coating composition according to any one of the preceding aspects, wherein the magnesium oxide has a number-average particle size of not more than 50 micrometers, such as not more than 30 micrometers, as measured using a transmission electron microscope.

[0122] Aspect 11. The coating composition according to any one of the preceding aspects, wherein the magnesium oxide has a number-average particle size of 0.5 micrometers to 50 micrometers, such as 1 micrometer to 30 micrometers, as measured using a transmission electron microscope.

[0123] Aspect 12. The coating composition according to any one of the preceding aspects, wherein the magnesium oxide has a number-average particle size of at least 10 nm as measured using a transmission electron microscope.

[0124] Aspect 13. The coating composition according to any one of the preceding aspects, wherein the magnesium oxide has a number-average particle size of not more than 499 nm, such as not more than 100 nm, as measured using a transmission electron microscope.

[0125] Aspect 14. The coating composition according to any one of the preceding aspects, wherein the magnesium oxide has a number-average particle size of 10 nm to 499 nm, such as 10 nm to 100 nm, as measured using a transmission electron microscope.

[0126] Aspect 15. The coating composition according to any one of the preceding aspects, wherein the magnesium oxide comprises ultrafine particles.

[0127] Aspect 16. The coating composition according to any one of the preceding aspects, wherein the magnesium oxide has at least 10 μm as determined by nitrogen adsorption according to ASTM D3663-78. 2 / g BET specific surface area.

[0128] Aspect 17. The coating composition according to any one of the preceding aspects, wherein the magnesium oxide has a nitrogen adsorption capacity of 30 μm as determined by nitrogen adsorption according to ASTM D3663-78. 2 / g to 500 m 2 / g, such as 80 m 2 / g to 250 m 2 / g BET specific surface area.

[0129] Aspect 18. The coating composition according to any one of the preceding aspects, wherein the magnesium oxide has a spherical morphology, a cubic morphology, a lamellar morphology, a polyhedral morphology and / or a needle-like morphology.

[0130] Aspect 19. The coating composition according to any one of the preceding aspects, comprising at least 6% by weight, such as at least 20% by weight, of the magnesium oxide based on the total solid weight of the coating composition.

[0131] Aspect 20. The coating composition according to any one of the preceding aspects, comprising, based on the total solid weight of the coating composition, an amount not exceeding 60% by weight, such as not exceeding 50% by weight, of the magnesium oxide.

[0132] Aspect 21. The coating composition according to any one of the preceding aspects, comprising, based on the total solid weight of the coating composition, an amount of magnesium oxide of 6% to 60% by weight, such as 20% to 50% by weight.

[0133] Aspect 22. The coating composition according to any one of the preceding aspects, wherein the lithium compound comprises lithium oxide, lithium dihydrogen phosphate, lithium oxalate and / or lithium salts, such as lithium hydroxide, lithium sulfate, lithium citrate, lithium acetate, lithium tartrate and / or lithium nitrate.

[0134] Aspect 23. The coating composition according to any one of the preceding aspects, wherein the lithium compound has a Ksp of at least 1, such as at least 5, in water at 25°C.

[0135] Aspect 24. The coating composition according to any one of the preceding aspects, wherein the lithium compound has a Ksp of at least 10, such as at least 20, in water at 25°C.

[0136] Aspect 25. The coating composition according to any one of the preceding aspects, wherein the lithium compound has a Ksp in water at 25°C not exceeding 1,000, such as not exceeding 500.

[0137] Aspect 26. The coating composition according to any one of the preceding aspects, wherein the lithium compound has a Ksp of 0.05 to 1,000, such as 1 to 1,000, in water at 25°C.

[0138] Aspect 27. The coating composition according to any one of the preceding aspects, wherein the lithium compound has a Ksp of 5 to 1,000, such as 10 to 1,000, in water at 25°C.

[0139] Aspect 28. The coating composition according to any one of the preceding aspects, wherein the lithium compound has a Ksp of 20 to 500 in water at 25°C.

[0140] Aspect 29. The coating composition according to any one of the preceding aspects, wherein the lithium compound has a water solubility at 20°C of greater than 3 g / 100 ml, such as greater than 5 g / 100 ml.

[0141] Aspect 30. The coating composition according to any one of the preceding aspects, wherein the lithium compound has a water solubility at 20°C of greater than 8 g / 100 ml, such as greater than 10 g / 100 ml.

[0142] Aspect 31. The coating composition according to any one of the preceding aspects, wherein the lithium compound has a water solubility of greater than 12 g / 100 ml at 20 °C.

[0143] Aspect 32. The coating composition according to any one of the preceding aspects, wherein the lithium compound has a water solubility at 30°C greater than 3 g / 100 ml, such as greater than 5 g / 100 ml.

[0144] Aspect 33. The coating composition according to any one of the preceding aspects, wherein the lithium compound has a water solubility at 30°C greater than 8 g / 100 ml, such as greater than 10 g / 100 ml.

[0145] Aspect 34. The coating composition according to any one of the preceding aspects, wherein the lithium compound has a water solubility of greater than 12 g / 100 ml at 30 °C.

[0146] Aspect 35. The coating composition according to any one of the preceding aspects, comprising at least 0.01% by weight, such as at least 0.05% by weight, of the lithium compound based on the total solid weight of the composition.

[0147] Aspect 36. The coating composition according to any one of the preceding aspects, comprising less than 1% by weight, such as not more than 0.5% by weight, of the lithium compound based on the total solid weight of the composition.

[0148] Aspect 37. The coating composition according to any one of the preceding aspects, comprising, based on the total solid weight of the composition, an amount of the lithium compound from 0.01 wt% to less than 1 wt%, such as 0.05 wt% to 0.5 wt%.

[0149] Aspect 38. The coating composition according to any one of the preceding aspects, comprising at least 0.01 vol% such as at least 0.05 vol% of the lithium compound based on the total solid volume of the composition.

[0150] Aspect 39. The coating composition according to any one of the preceding aspects, comprising less than 1% by volume, such as not more than 0.5% by volume, of the lithium compound based on the total solid volume of the composition.

[0151] Aspect 40. The coating composition according to any one of the preceding aspects, comprising, based on the total solid volume of the composition, an amount of the lithium compound from 0.01 vol% to less than 1 vol%, such as from 0.05 vol% to 0.5 vol%.

[0152] Aspect 41. The coating composition according to any one of the preceding aspects, further comprising a corrosion inhibitor in addition to the magnesium oxide and the lithium compound.

[0153] Aspect 42. The coating composition according to aspect 41, comprising at least 0.05% by weight, such as at least 0.1% by weight, of an additional corrosion inhibitor based on the total solid weight of the coating composition.

[0154] Aspect 43. The coating composition according to aspect 41 or aspect 42, comprising, based on the total solid weight of the coating composition, not more than 5% by weight, such as not more than 4% by weight, the additional corrosion inhibitor.

[0155] Aspect 44. The coating composition according to any one of Aspects 41 to 43, comprising, based on the total solid weight of the coating composition, an amount of the additional corrosion inhibitor, such as 0.1% to 4% by weight.

[0156] Aspect 45. The coating composition according to any one of Aspects 1 to 40, wherein the coating composition is substantially free of, or essentially free of, or completely free of corrosion inhibitors other than the magnesium oxide and the lithium compound.

[0157] Aspect 46. The coating composition according to the foregoing aspect, wherein the coating composition is substantially free of, or essentially free of, or completely free of zinc salts of molybdenum, hexavalent chromium, and / or 2,5-dimercapto-1,3,4-thiadiazole.

[0158] Aspect 47. The coating composition according to any one of the preceding aspects, wherein the coating composition is formulated as a liquid solvent-based coating composition.

[0159] Aspect 48. The coating composition according to any one of Aspects 1 to 46, wherein the coating composition is formulated as a liquid water-based coating composition.

[0160] Aspect 49. The coating composition according to any one of Aspects 1 to 46, wherein the coating composition is formulated as a powder coating composition, a thermosetting composition, a thermoplastic composition, a 1K composition and / or a multi-component composition such as a 2K composition.

[0161] Aspect 50. A method for coating a substrate, the method comprising: applying a coating composition according to any one of the preceding aspects to the surface of the substrate to form a coating.

[0162] Aspect 51. The method according to aspect 50, further comprising applying a second coating composition to a first coating to form a second coating.

[0163] Aspect 52. A substrate comprising a coating on its surface, said coating being formed of a coating composition according to any one of Aspects 1 to 49.

[0164] Aspect 53. The substrate according to aspect 52, wherein the coating has a dry film thickness of 0.5 mil to 10 mil.

[0165] Aspect 54. The substrate according to aspect 52 or aspect 53, comprising a second coating formed on the first coating.

[0166] Aspect 55. The substrate according to aspect 54, wherein the second coating comprises a silicone-modified polyester coating, a fluoropolymer coating, and / or a polyurethane coating.

[0167] Aspect 56. The base material according to any one of Aspects 52 to 55, comprising metals such as aluminum and / or steel; and / or metal alloys such as aluminum alloys containing copper.

[0168] Aspect 57. The substrate according to any one of Aspects 52 to 56, which is in the form of a metal sheet, a roll, an aircraft component and / or a three-dimensional assembly formed by an additive manufacturing process.

[0169] Aspect 58. The substrate according to any one of Aspects 52 to 57, wherein there is no intermediate layer between the substrate and the coating, or the substrate includes one or more intermediate layers between the substrate and the coating, such as an aluminum cladding layer, an anodized layer, a conversion coating such as a chromate conversion coating, a non-chromate treatment, and / or a pretreatment.

[0170] Aspect 59. The substrate according to any one of Aspects 52 to 58, wherein the substrate includes aircraft, vehicles, personal electronic devices, parts, articles of manufacture and / or components thereof.

[0171] Aspect 60. Use of the composition according to any one of aspects 1 to 49 for forming a coating that does not exhibit pitting corrosion in a debonding corrosion pitting test.

[0172] Aspect 61. The use of the coating as described in aspect 60, wherein the coating exhibits a pencil hardness rating of 4H after immersion in SKYDROL.

[0173] Aspect 62. The coating used for forming a coating according to aspect 60 or aspect 61, wherein the coating exhibits a dry adhesion rating of 5B.

[0174] Aspect 63. Use for forming a coating according to any one of Aspects 60 to 62, wherein the coating exhibits a wet adhesion rating of 5B.

[0175] Aspect 64. The use according to any one of Aspects 60 to 63, for forming a coating that exhibits a scribing gloss rating of at least 30, such as at least 70, after 1,000 hours of salt spray testing on an exposed 2024-T3 aluminum panel in accordance with ASTM B117-19.

[0176] Section 65. The use according to any one of Sections 60 to 64, for forming a coating that exhibits 10 or fewer, such as 5 or fewer, scribing bubbles after 1000 hours of salt spray testing on an exposed 2024-T3 aluminum panel in accordance with ASTM B117-19.

[0177] Aspect 66. The use according to any one of Aspects 60 to 65, for forming a coating that exhibits a maximum scribbled bubble size of 6.0 mm or less, such as 3.0 mm or less, after 1,000 hours of salt spray testing on an exposed 2024-T3 aluminum panel in accordance with ASTM B117-19.

[0178] Aspect 67. The use according to any one of Aspects 60 to 66, for forming a coating that exhibits a scribing gloss rating of 0 after 1000 hours of salt spray testing on an exposed 2024-T3 aluminum panel according to ASTM B117-19.

[0179] Example

[0180] The following examples are intended to illustrate this disclosure and should not be construed as limiting this disclosure in any way.

[0181] Preparation of coating composition

[0182] Coating compositions were prepared using magnesium oxide (MgO) and lithium salt raw materials as shown in Table 1, namely the control and Examples 1-4.

[0183] Table 1: Raw Materials and Suppliers

[0184]

[0185] Epoxy-amine 2K (two-component) coating compositions were prepared using the components and weights shown in Table 2, namely the control and examples 1-4.

[0186] Table 2: Coating compositions of comparison and examples 1-4

[0187]

[0188] For each Part 1, all components were weighed and placed in glass jars. Dispersion medium was then added to each jar at approximately 35% of the total weight of each Part 1. The jars were sealed with lids and placed on a Lau DAS 200 dispersion unit (Lau GmbH) for 3 hours of dispersion. All final dispersions had a Hegman meter reading greater than 7. Part 2 was prepared in a similar manner. Prior to coating application, the corresponding amounts of Part 1 and Part 2 shown in Table 2 for each coating composition were combined, thoroughly mixed, and allowed an induction time between 10 and 15 minutes.

[0189] The weight percentages of the composition components based on the total solids weight of the controls and Examples 1-4 are summarized in Table 3. The volume percentages of the composition components based on the total solids volume of the controls and Examples 1-4 are summarized in Table 4.

[0190] Table 3: Summary of MgO and Lithium Salt Percentages by Total Solid Weight

[0191]

[0192] Table 4: Summary of MgO and Lithium Salt Percentage by Total Solid Volume

[0193]

[0194] Preparation and testing methods of coating materials

[0195] Sample preparation and testing methods for debonding corrosion test: The debonding corrosion test is designed to simulate corrosion caused by water or salt water trapped in bubbles beneath a coating that has debonded from a metal substrate.

[0196] The coating compositions of Control and Examples 1-4 were sprayed onto 6 cm x 10 cm polycarbonate sheets to a thickness of 0.6-1.2 mils and allowed to cure at room temperature for 14 days. Each coated sheet was then assembled with a 7.6 cm x 15.2 cm uncoated clad 2024-T3 aluminum panel, with the coated side of the polycarbonate sheet facing the uncoated clad aluminum panel. The assemblies were sealed on three sides with a commercial sealant (PR-1776, available from PPG Aerospace, CA, US, and cured to manufacturer specifications). The assemblies produced an open envelope structure with a gap at the top. The gap in the assemblies was filled with a 0.5 wt% sodium chloride (NaCl) solution. The samples were held at 50°C for 7 days and refilled daily with deionized water. After seven days of testing, pitting on the clad aluminum surface was visually inspected and rated as severe, moderate, mild, or no pitting according to the parameters listed in Table 5.

[0197] Table 5

[0198]

[0199] Preparation of coated metal panels: Clean the bare or coated 2024-T3 aluminum panel with acetone, followed by wet buffing with a SCOTCH-BRITE 7447 pad to create a waterproof surface. As used herein, a waterproof surface is defined as a surface that maintains a continuous water film for at least 30 seconds after rinsing with clean water at room temperature. Rinse the panel thoroughly with water and allow it to dry. Perform a final wipe with methyl ethyl ketone before applying the coating.

[0200] The coating compositions (controls and Examples 1-4) were sprayed onto a 2024-T3 aluminum alloy substrate panel using an air atomizing spray gun to achieve a dry film thickness between 0.6 and 1.2 mils. After drying at room temperature for 2 hours, a commercially available polyurethane coating CA8000 / B70846 (PPG Aerospace, California) was applied on top of each coating film (controls and Examples 1-4). In this example, the coating system containing the controls or Examples 1-4 and the polyurethane coating was allowed to cure at room temperature for 14 days prior to any testing.

[0201] Coated panel test procedure

[0202] Salt spray corrosion resistance of coated metal panels The corrosion resistance of the coated metal panels was determined according to ASTM B117-19 (Standard Practice for Operating Salt Spray (Fog) Apparatus). Test panels were prepared using at least three polished bare or coated aluminum panels with a thickness of approximately 0.032 inches, as described above. Two diagonal markings (scribing lines) were machine-drilled lines extending from one corner to the other on each panel. The width of the scribing lines was between 0.031 and 0.064 inches, penetrating the coating and extending into the base metal. The test panels were exposed to 5% salt spray for 1000 hours or 3000 hours, with the coated side facing up.

[0203] Inspect the panel for corrosion and bubbles after salt spray exposure according to the following evaluation criteria:

[0204] Scratch corrosion: Rating from 0 to 100, where the number represents the percentage of scratched areas showing visible corrosion, with lower ratings being better.

[0205] Streak Gloss / Status: Rating from 0 to 100, where the number represents the percentage of bright streaks in the streak, with higher ratings being better.

[0206] Bubbles: The total number of bubbles near and away from the scribbles (i.e., on the panel surface). The bubble count is up to 30, with lower ratings being better.

[0207] Bubble size: Measured in millimeters (mm) at the size of the largest bubble near the scribe line.

[0208] Cross-cut adhesion test:Cross-cut adhesion was determined according to Method B of ASTM D3359-17 (Standard Test Methods for Measuring Adhesion by Tape Test). A cross-cut pattern was drawn through the coating down to the substrate. A 1-inch (25.4 mm) wide masking tape (such as 3M 250 or equivalent) was applied to the scored coating. The tape was pressed down using two passes of a 4.5 lb rubber-coated roller. The tape was then removed in a sudden motion perpendicular to the panel. Adhesion was rated by visual inspection of the coating at the scored areas using the provided rating system. Dry adhesion was tested after the coating system had fully cured for 14 days. Wet adhesion of the fully cured coating system was tested after immersing the test panel in water at 75℉ (23°C) for 24 hours. The panel was removed from the water, dried with a paper towel, and tested after 5 minutes.

[0209] Pencil hardness: Pencil hardness was determined according to ASTM D3363-22 (Standard Test Method for Film Hardness by Pencil Test). The hardness of each coating composition was determined by scratching a pencil lead approximately one-quarter inch across the coating at a 45-degree angle, relative to a set of standard pencil leads. This process was repeated until a pencil lead that did not scratch the film was identified. The pencil lead number was recorded as the hardness.

[0210] SKYDROL resistance: The fully cured coated panel was immersed in the hydraulic fluid SKYDROL LD-4 (available from Solutia, Inc.) at room temperature for 30 days. After 30 days of immersion, the panel was removed from the fluid, dried with a paper towel, and immediately tested for pencil hardness.

[0211] Test Results

[0212] Results of debonding and corrosion resistance test: Table 6 describes the debonding corrosion pitting results after 7 days of salt exposure.

[0213] Table 6: Results of debonding corrosion and pitting

[0214]

[0215] As shown in Table 6, the corrosion pitting resistance of all examples containing MgO particles and lithium salts was significantly improved compared to the control.

[0216] Table 7 shows the pencil hardness, dry adhesion, and wet adhesion of bare 2024-T3 aluminum panels coated with control or examples 1, 2, or 3 and polyurethane coatings, as well as the pencil hardness after a SKYDROL immersion test. All coating systems exhibit comparable pencil hardness, adhesion, and SKYDROL resistance.

[0217] Table 7: Pencil Hardness and Adhesion on Polished Bare 2024-T3 Aluminum

[0218]

[0219] Table 8 shows the corrosion performance of bare 2024-T3 aluminum panels coated with control or examples 1, 2 or 3 and polyurethane coatings after 1000 hours of exposure.

[0220] Table 8: Corrosion results after 1,000 hours of neutral salt spray on polished bare aluminum.

[0221]

[0222] Table 9 shows the corrosion performance of 2024-T3 aluminum panels coated with control or examples 1, 2 or 3 and polyurethane coating after 1000 hours of exposure.

[0223] Table 9: Corrosion results after 1,000 hours of neutral salt spray on polished coated aluminum.

[0224]

[0225] Table 10 shows the corrosion performance of 2024-T3 bare aluminum panels coated with control or example 1 or 4 and polyurethane coating after 3000 hours of exposure.

[0226] Table 10: Corrosion results on polished bare aluminum after 3,000 hours of neutral salt spray.

[0227]

[0228] Table 11 shows the corrosion performance of 2024-T3 bare aluminum panels coated with control or example 1 or 4 and polyurethane coating after 3000 hours of exposure.

[0229] Table 11: Corrosion results on polished coated aluminum after 3,000 hours of neutral salt spray.

[0230]

[0231] The corrosion resistance results shown in Tables 8 to 11 demonstrate that, compared with the control, metal panels coated with the coating composition of this disclosure (comprising a film-forming binder, magnesium oxide particles, and a lithium salt (such as lithium hydroxide or lithium sulfate)) (Examples 1-4) provide improved corrosion resistance.

[0232] Although specific features of this disclosure have been described above for illustrative purposes, it will be apparent to those skilled in the art that various changes may be made to the details of the coating compositions, coatings, and methods disclosed herein without departing from the scope of the appended claims.

Claims

1. A coating composition comprising: (a) Film-forming adhesives; (b) Magnesium oxide; and (c) Lithium compounds in amounts ranging from 0.01% to less than 1% by weight of total solids. The lithium compound has a solubility constant (Ksp) in water at 25°C greater than 0.

05.

2. The coating composition according to claim 1, wherein the film-forming binder comprises an organic resin.

3. The coating composition of claim 2, wherein the film-forming adhesive further comprises a curing agent.

4. The coating composition according to claim 3, wherein: (a) The organic resin contains epoxide functional groups; and / or (b) The curing agent contains amine functional groups.

5. The coating composition according to any one of the preceding claims, wherein the coating composition comprises, based on the total solid weight of the coating composition, an amount of the film-forming binder from 20% to 90% by weight.

6. The coating composition according to any one of the preceding claims, wherein the coating composition comprises 6% to 60% by weight of the magnesium oxide based on the total solid weight of the coating composition.

7. The coating composition according to any one of the preceding claims, wherein the lithium compound comprises a lithium salt.

8. The coating composition according to claim 7, wherein the lithium salt comprises lithium sulfate and / or lithium hydroxide.

9. The coating composition according to any one of the preceding claims, wherein the coating composition is substantially free of molybdenum.

10. The coating composition according to any one of the preceding claims, further comprising a third corrosion inhibitor in addition to the magnesium oxide and the lithium compound.

11. The coating composition of claim 10, wherein the coating composition comprises, based on the total solid weight of the composition, an amount of the third corrosion inhibitor from 0.01% to 5% by weight.

12. The coating composition according to any one of the preceding claims, wherein it is formulated as a liquid coating composition or a powder coating composition.

13. The coating composition according to any one of the preceding claims, wherein the coating composition is substantially free of hexavalent chromium.

14. A method for coating a substrate, the method comprising: The coating composition according to any one of the preceding claims is applied to the surface of the substrate to form a first coating.

15. A substrate comprising a coating on its surface, said coating being formed from a coating composition according to any one of claims 1 to 13.

16. The substrate of claim 15, comprising a second coating formed on the first coating.

17. The substrate of claim 16, wherein the second coating comprises a silicone-modified polyester coating, a fluoropolymer coating, and / or a polyurethane coating.

18. The substrate according to any one of claims 15 to 17, comprising a metal or metal alloy, such as aluminum or steel.

19. The substrate of claim 18, wherein the metal alloy comprises a copper-containing aluminum alloy.

20. The substrate according to any one of claims 15 to 19, wherein it is in the form of a sheet metal, a coil metal, or an aircraft component.

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