Water-based coating compositions for different colors and related products and processes

Abstract

Described herein are water-based coating compositions including one or more synthetic polymer binders, a cross-linker, a pigment, a wetting additive, a dispersing additive, and up to 50 wt. % dry weight of a polyamide. Described also herein are methods and processes related to the production of the coating compositions, as well as the methods of applying the coating compositions to substrates.

Description

WATER-BASED COATING COMPOSITIONS FOR DIFFERENT COLORS AND RELATED PRODUCTS AND PROCESSESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 567,699, filed March 20, 2024, which is hereby incorporated by reference in its entirety for all intents and purposes.FIELD

[0002] The invention relates to the fields of material science, material chemistry, polymers, polymer chemistry, synthetic coatings and paints, aluminum product manufacturing and related fields. The invention provides novel water-based polymer coating compositions and related products and processes, which can be employed in production of aluminum products.BACKGROUND

[0003] Polymer-based synthetic coatings are widely used in industries using aluminum parts and components to create protective and / or decorative coatings on aluminum surfaces. Some examples of such coatings are paints and clear coatings used on architectural and automotive panels and components. Coating compositions used to treat aluminum parts and components have to meet various demands. Such coating compositions have to be formulated so that they create coatings with specific properties and characteristics demanded by the industries and the consumers. For example, the coatings have to be adherent, exhibit good abrasion resistance, exhibit mechanical deformability (flexibility) and resist various environmental factors, such as temperature, humidity and exposure to ultraviolet radiation. Continuous automated industrial coating processes create their own demands. For example, coating compositions used in coil coating, which is employed for coating coiled metal sheets before they are cut or otherwise formed, need to be applied quickly in a thin, uniform layer over large surface areas, and dry and cure in sufficiently short time to ensure high efficiency of the coating line.

[0004] Coating formulations that employ polyester, polyurethane, and / or other synthetic polymer binders in combination with polyamide are popular for coil coating applications, such as the production of roller shutters and architectural panels. Addition of colored pigments is desirable for producing color-coated products. However, incorporation anddispersion of sufficiently high levels of pigments into synthetic polymer coating formulations used in coil coating applications is difficult and the pigments need to be stabilized if the coatings are to be stored prior to use, such that the coating formulations maintain even distribution of the pigment. Additionally, coating formulations incorporating pigments typically are based on organic solvents, which limit coil coating applications due to the operating temperatures required when organic vapors from organic solvents are present, and also contribute to larger organic solvent waste streams.SUMMARY

[0005] The terms “invention,” “the invention,” “this invention” and “the present invention,” as used in this document, are intended to refer broadly to all of the subject matter of this patent application and the claims below. Statements containing these terms should be understood not to limit the subject matter described herein or to limit the meaning or scope of the patent claims below. Covered embodiments of the invention are defined by the claims, not this summary. This summary is a high-level overview of various aspects of the invention and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification, any or all drawings and each claim.

[0006] Described herein is a coating composition including one or more synthetic polymer binders, a cross-linker, a pigment, a wetting additive, a dispersing additive, and up to 50 wt. % dry weight of a polyamide. In some examples, the coating composition further includes up to 80 wt. % water and one or more organic solvents. In some examples, the one or more synthetic polymer binders includes a polyurethane and a polyester. In some examples, the coating composition includes 20-60 wt. % dry weight of the one or more synthetic polymer binder. In some examples, the coating composition includes up to 5 wt. % dry weight of the polyamide. In some examples, the coating composition includes 0.1-60 wt. % dry weight of the pigment. In some examples, the coating composition includes a dry weight ratio of the polyamide to the synthetic polymer binder from 1 : 10 to 1 :3. In some examples, no polyamide is present in the coating composition. In some examples, the crosslinker includes one or more polyisocyanates, blocked polyisocyanates, or combinations thereof. In some examples, the coating composition further includes an epoxy from 0.1 to 10 wt. % dry weight. In some examples, the coating composition further includes one or more ofdefoaming additives, rheology additives, or combinations thereof. In some examples, the coating composition has a viscosity of 15-150 seconds measured with 4 mm ISO cup at 23

[0007] Also provided herein is a substrate including a coating layer formed from the coating composition described herein. In some examples, the coating layer is dry and comprises a thickness of 1-25 pm. In some examples, the coating layer has a gloss level of 1- 80 gloss units. In some examples, the substrate includes a metal, such as, but not limited to, aluminum.

[0008] Also described herein is a process of applying a coating to a substrate including applying a composition including one or more synthetic polymer binders, a cross-linker, a wetting additive, a dispersing additive, and up to 50 wt. % dry weight of a polyamide to an aluminum substrate and drying the composition to produce a coated aluminum substrate. In some examples, the substrate is an uncoiled aluminum sheet. In some examples, drying step of the process is conducted at a Peak Metal Temperature of 150 to 250 °C for 5-100 seconds.BRIEF DESCRIPTION OF THE FIGURES

[0009] FIG. 1A-1B is a schematic illustration of a roller shutter. FIG. 1A shows an installed and rolled roller shutter. FIG. IB shows a cross-section of a roller shutter.

[0010] FIG. 2 is a schematic illustration of a cross-section of an aluminum substrate (1) with several coatings, including pre-treatment coating (2), paint coating (3), clear coating (4).

[0011] FIG. 3A-3B is a schematic illustration of a coil -coating line. FIG. 3A schematically illustrates a line with one coating room (inset), which is shown in more detail in FIG. 3B.DESCRIPTIONCompositions

[0012] Disclosed are improved water-based synthetic polymer coating compositions, which can be referred to as “formulations,” “paint,” “coat,” “coat paint,” “varnish,” “coating” or other related terms, in singular or plural. The improved coating compositions are waterbased, generally meaning that they contain water as a principal solvent, in contrast to organic solvent-based coating compositions, which employ nonaqueous organic solvents as principal solvents. The water-based coating compositions may also include nonaqueous organic solvents, in addition to water. The improved coating compositions are qualified as “synthetic polymer” coating compositions, meaning that the coating formed by the compositions on asubstrate contains synthetic polymer binder molecules. The improved coating compositions also comprise one or more pigments in an amount of 0.1 to about 60 % by weight of the dry coating formulation (“dry weight”), one or more dispersing additives in an amount from about 0.1 to about 5% by weight of the dry coating formulation, and one or more wetting additives in an amount between 0.1 and 8% by weight of the dry weight of the coating formulation.

[0013] The term “dry weight,” is used in this document to characterize the content or the amount of a certain component present in a coating composition, other than water and nonaqueous organic solvents. In some cases, “dry weight” means the ratio (which may be expressed as a percentage) of the solids of the component in question to the total weight of the composition, wherein the weight of the water and organic solvents is excluded from the total weight. For example, in reference to polyamide, “dry weight” means the ratio of polyamide powder weight to the total weight of the components present in the composition, where the total weight does not include the weight of the water and organic solvents. In reference to polyurethane and other synthetic polymer binders typically provided as a waterborne liquid suspension, dry weight means the ratio of binder solids present in the suspension (not the weight of the suspension) to the total weight of the composition, where the total weight does not include the weight of the water and other solvents. In some other cases, namely, when the component in question is a liquid or a semi-liquid compound, “dry weight” may mean the ratio of the weight of the liquid or a semi-liquid compound to the total weight of the components present in the composition, wherein the total weight does not include the weight of the water and other solvents. The content of water and organic solvents in the composition is described not as a dry weight but as a ratio (which may be expressed as a percentage) of the weight of water or an organic solvent to the weight of the final composition, the weight of the final composition including water and / or organic solvent or solvents.

[0014] The improved coating compositions may also comprise cross-linkers and one or more other components (which can be termed “additive” or “additives”), such as defoamers, wetting additives, dispersing additives, rheology additives, epoxies, catalysts (for example, catalysts for polyurethane formation, such as amine compounds or metal complexes), waxes, matting agents, light stabilization, and other additives. The improved coating compositions of the present invention are suitable for coating of metal substrates, such as aluminum substrates. After a coating process, which includes the steps of (1) application of the coatingcomposition onto the metal substrate, (2) drying, and (3) curing, the coating compositions form a protective and / or decorative coating on the metal substrate. The improved coating compositions form a coating with various advantageous properties, such as flexibility, adhesion, resistance to abrasion, and resistance to dust and other environmental influences such as ultraviolet radiation. In the improved coating compositions, one or more of these properties are advantageously improved in comparison to previously known organic solventbased polyamide-containing coatings. The improved coating compositions and the advantages afforded by these compositions are further discussed below.

[0015] The terms “synthetic polymer,” “binder,” “synthetic polymer binder” “film former” and the related terms, as used in this document, refer to synthetic polymers that form a film in a coating formed by the coating compositions upon the steps of (1) application of the coating composition on a substrate, (2) drying, and / or (3) curing. Synthetic polymer binders can also be described as film-forming components of the coating compositions. In some cases, the synthetic polymer binders can also be referred to as “resin,” “resins,” or related terms. Upon application of the coating composition on the substrate, the binder forms a film during the process of drying or curing. Although drying may refer to evaporation of the solvent or thinner, it often refers to cross-linking of the binders, and the term may be used indistinguishably from the term “curing.” Coating compositions may rely on polyaddition or cross-linking processes occurring in the film-forming component during drying or curing. Curing agents, including catalysts, cross-linking agents, inducers and other types of agents may be employed to induce or facilitate curing, as explained further in this document and illustrated by the descriptions of the relevant processes.

[0016] While the coating compositions need to contain at least one synthetic polymer binder component, in some cases more than one (one or more) synthetic polymer binder components, such as two or more, three or more, or four or more components may be employed. The film-forming components of a coating composition influence adhesion and other properties of the coating formed by a coating composition, such as gloss, flexibility, and abrasion resistance. Film-forming components of the coating compositions according to some examples include synthetic polymer binders that can be employed in water-based compositions. Some non-limiting examples of synthetic binders suitable for the improved coating compositions are polyurethanes, polyesters, polyacrylates (also known as acrylate polymers or acrylics), alkyds, vinyl-acrylics, vinyl acetate-ethylene, polyvinyl acetate, styrene acrylic co-copolymers, melamine resins, and epoxy resins. Synthetic polymer binders can be supplied as waterborne dispersions, for example, waterborne acrylic, polyurethane, orpolyester dispersions, which may be used in preparation of the disclosed coating compositions. The improved coating compositions may contain from approximately 20-60 % (e.g., 35-55, or 40-50%) of the synthetic polymer binder component, dry weight. For example, an improved coating composition can contain 20, 25, 30, 35, 40, 45 or 50 % dry weight polyurethane. In another example, an improved coating composition contains approximately 0.5-10 % dry weight polyester (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 %) and / or 0.1-5 % dry weight acrylic (e.g., 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, or 5 %).

[0017] The term “polyurethane” (PU) or polyurethane dispersion (PUD) and related terms, as used in this document, refer to co-polymers produced from polyisocyanates (meaning isocyanates that have multiple (two or more) isocyanate (NCO) groups on each molecule) and polyols (meaning compounds with multiple (two or more) functional hydroxyl groups), such as diols. Various types of polyisocyanates may be employed in PU formation. A PU polyaddition reaction proceeds via NCO groups of polyisocyanates and hydroxyl groups of polyols. PU-based coating compositions may be formulated with “blocked” polyisocyanates, in which NCO groups are blocked with a protecting moiety, thus preventing polyaddition of the coating compositions until they are heated in order to remove the protecting moiety. High temperatures “deblock” the NCO groups, which allows a polymerization reaction with polyols to proceed, resulting in formation of PU molecules. Thus, PUs based on “blocked” polyisocyanates can be polymerized after application of compositions including the polyisocyanates and polyol components onto a substrate. The polyaddition is initiated by heating to “deblock” the NCO groups, thus removing the protecting moiety. Coating compositions may also be formulated with reacted PU formulations produced by reacting an excess of polyisocyanates with a polyol or mixture of polyols (e.g., polyester polyols, polyether polyols, or polycarbonate polyols) to form a prepolymer. For example, the improved coating compositions can be formulated as waterborne dispersions of fully reacted PU, referred to as PUD. The PUD are provided as small particles of PU (for example, 0.1 to 3.0 pm in size), dispersed in water to form a chemically and colloidally stable dispersion. The dispersion can be stabilized by external emulsifiers or by including hydrophilic centers (such as cationic or anionic groups) in the polymer. Some examples of PUD suitable for inclusion into the disclosed compositions are waterborne dispersions of polycarbonate-based or polyester-based PU stabilized by hydrophilic centers. In addition to PUD, the disclosed compositions may include PU’s with “blocked” isocyanate components. These blocked PU’s may be referred to as “hardeners” or “cross-linkers,” and they react with prepolymer molecules upon application of the coatingcomposition onto a metal substrate and subsequent heating. In some examples, the isocyanates can be blocked with caprolactam, oximes, and 3,5 -dimethylpyrazole. The disclosed compositions can include more than one (two, three, four, etc.) type of PU, more than one (two, three, four, etc.) type of PUD, and more than one (two, three, four, etc.) type of isocyanate.

[0018] The term “polyester” (PE) or “polyester dispersion” (PED) and related terms, as used in this document, refer to one of the binder components that can be used to formulate the disclosed coating compositions. The terms refer to a category of polymers that contain ester functional groups in their main chain. Various types of PEs may be employed in the improved coating compositions, such as aliphatic or aromatic PEs. The terms “acrylate,” “polyacrylate,” “acrylic” and the related terms refer to polymers derived from acrylic acid and related compounds. In some cases, derivatives or co-polymers of the above compounds with other compounds may be employed in the disclosed coating compositions.

[0019] The terms hardeners and cross-linkers and the related terms, as used in this document, refer to compounds that link one polymer chain to another. They may be incorporated into the disclosed coating compositions. For example, various types of isocyanates may be employed as cross-linkers. Such isocyanates include, but are not limited to, aliphatic diisocyanate monomers and cyclic isocyanates. Blocked polyisocyanates employed in two-component PU systems which polymerize upon heating may be referred as “hardeners” and may be incorporated into the disclosed coating compositions. In another example, melamine cross-linkers may be employed.

[0020] The term “polyamide” (PA) as used in this document refers to a polymer with amide functionality. Some examples of PAs that can be suitably incorporated into the compositions of present invention are PA 12 and PA 11. PA 12 is a polyamide with a hydrocarbon chain containing 12 carbons between each amide linkage, while PA 11 has 11 carbons between each amide linkage. Both PA 11 and PA 12 show similar properties, such as low water absorption and / or abrasion resistance. Some examples of PA 12 suitable for the compositions for the present invention are Orgasol® supplied by Arkema® or Vestosint® supplied by Evonik®. An example of suitable PA 11 is Rilsan® supplied by Arkema®. Other examples of PAs that can be suitably incorporated into the compositions of the present invention PAs known under the generic designation of “Nylon.” For example, a polymer of co-aminolauric acid monomers or laurolactam monomers may be referred to as Nylon 12. PAs included in coating compositions are typically insoluble and are incorporated into the compositions in powdered form. PA powders that can be incorporated into the compositionsof the present invention include ground powders and precipitated powders. PA is typically provided (“delivered”) in powdered form. A PA powder can be described by “particle size” or “average particle size,” meaning “average particle diameter” or d50, which can be in the range of approximately 1 to approximately 100 pm. The disclosed compositions can include more than one (two, three, four, etc.) type of PA powder, such as powders of different PAs or their mixtures or powders of different average particle size. In coating compositions, the PA component or components may act as texturing agent. Also, PA molecules contain reactive terminal groups, such as terminal carboxyl and terminal amino groups, which react with other components of the coating composition during the coating process. For example, in a coating composition the NCO groups of the isocyanate react with the terminal carboxyl and terminal amino groups of PA, and with the hydroxyl groups of PUD and / or PE. Water-based coating compositions according to some examples can comprise PA in an amount of up to about 50%, 0-5%, 0.1-4.5%, 0.2-4%, 0.3-3%, 0.4-2%, or 0.5-1% PA by dry weight. Water-based coating compositions as disclosed herein can contain various ratios, by dry weight, of PA to binder (for example, one or more of PU, PE or acrylic), for example, from about 0 to about 1 : 10 or greater. The term “ratio,” when used in this context, means ratio of the weight of PA powder to the weight of solid binder, such as one or more of PU, PE, or acrylic, in a unit weight of a composition. In comparison, known organic solvent-based coating products for metal substrates allow incorporation of a maximum of 50% PA by dry weight and a maximum PA / PU dry weight ratio of 1 :3.

[0021] In addition to one or more binder, PA and water, the disclosed coating compositions can contain various other components, such as, but not limited to, cross-linkers and / or catalysts (for example, for PU or PE film formation), defoamers, wetting additives, waxes, matting agents, light stabilizers, dyes, pigments, and / or organic solvents. Some nonlimiting examples of the components that can be incorporated into the coating compositions are described below. Defoamers are the agents having low surface tension that penetrate foam lamellae to destabilize them and make them burst. Some examples of the wetting additives employed in the disclosed compositions are polyether modified siloxanes, multi-functional siloxane surfactants, and alkoxylates. Waxes may be used to improve the glide properties of the surface and to improve scratch resistance. Some non-limiting examples of suitable waxes are carnauba wax, polyethylene wax, polyolefin wax, polytetrafluorethylene wax, and amide wax. While coating compositions are water-based, meaning that water is used as a principal solvent, nonaqueous water-miscible organic solvents, such as, but not limited to, esters, for example, butylglycol or Rhodiasolv® (e.g., a dibasic ester solvent), may be included in thecompositions of the present invention. Matting agents, such as micronized matting polyurea, may also be included.Table 1. Exemplary formulations of the improved coating compositions

[0022] The description provided below and in Table 1 illustrates formulation of exemplary coating compositions. The list of the components listed below and in Table 1 and described as “present” in the composition is non-limiting. Some examples of the compositions of the present invention include the listed components, but other componentsmay also be included. Some other examples may consist of only or essentially of the listed components. When the content range of the component has a lower limit of zero (0), it means that the presence of the component is not required (that is, is optional) at least in some of the compositions. Some examples of the compositions are as follows. In some examples, a synthetic polymer binder (meaning one or more binders) is present in an amount of 20-60, 40-60 or 40-50 % dry weight. In some other examples, a first binder is one or more of PU, PE, or acrylic, and is present in an amount of 20-60, 40-60 or 40-50 % dry weight. A second binder is present in an amount of 0-10, 0-5 or 1-5 % dry weight. A cross-linker (meaning one or more cross-linkers), such as, but not limited to, one or more of isocyanate or melamine, is present in an amount of 0.1-8, 0.1-5 or 0.1-4 % of dry weight. A PA (meaning one or more PAs), such as, but not limited to, one or both of PA 11 or 12, is present in an amount of 0-50, 0-10 or 0-5 % dry weight. A dispersing additive is present in an amount of 0 to 5% dry weight, 0.1 to 3 % dry weight, or 0.1 to 2 % dry weight. A rheology additive is present in an amount of 0 to 2 % dry weight, 0.5 to 2 % dry weight, or 1 to 2 % dry weight. A light stabilizer is present in an amount of 0 to 2 % dry weight, 0.5 to 2 % dry weight, or 1 to 2 % dry weight. A defoamer (meaning one or more defoamers) is present in an amount of 0-5, 1-3 or 1-2 % dry weight. A wetting additive (meaning one or more wetting additives) is present in an amount of 0.1 to 8 % dry weight, 0.1 to 5 % dry weight, or 0.1 to 1 % dry weight. A pigment (meaning one or more pigments) is present in an amount of 0.1-60, 5-35 or 10-30 % dry weight. Water is present in an amount of 1-80, 5-80, 1-70, 5-70, 10-70, 10-60, 20-70 or 30-50 % weight / weight of the final composition. Organic solvent is present in an amount of 0-50, 0-20 or 5-10 % weight / weight of the final composition.

[0023] Some coating compositions are used to create a “clear” coating layer, meaning a layer with a relatively high degree of visual transparency. Such a clear coating layer may be applied onto a metal substrate as a final protective layer after application of a paint coating. However, a paint coating need not be applied; a “clear” coating layer may be applied directly onto a metal substrate or after application of one or more of pretreatment or primer coatings. Even when the compositions are intended to create a “clear” coating, they may contain pigments or tints.

[0024] Some coating compositions are used to create opaque or colored coatings, and contain one or more pigments, tints or fillers to create a corresponding visual effect. Such colored coating compositions include one or more additives to stabilize the pigments in the compositions, including, but not limited to, an epoxy, a light stabilizer, an ultraviolet (UV) light absorber, a dispersing additive, a rheology additive, or combinations thereof. Suitableepoxies include, but are not limited to, a solid epoxy resin emulsion in water. In some examples, the epoxy facilitates dispersion of the pigment in the composition, and can contribute to advantageous drying and curing properties. Suitable light stabilizers include, but are not limited to, a hindered amine light stabilizer. Without being limited by theory, light stabilizers advantageously scavenge free radicals in the composition, inhibiting degradation of the polymer binder and chalking of the composition. Suitable UV absorbers include, but are not limited to, triazine-based UV absorbers. Without being limited by theory, UV absorbers can inhibit degradation of the polymer binder in the compositions by absorbing UV radiation and dissipating it as thermal energy. When included in the composition, dispersing additives can beneficially inhibit clumping of the one or more pigments in the composition, thereby stabilizing the distribution of the one or more pigments in the composition. In some examples, one or more rheology additives may be added to the composition to control the rheology (e.g., flow behavior, or viscosity) of the compositions to suspend the pigment particles in the composition. Suitable rheology modifiers include, but are not limited to, inorganic thickeners such as organoclays, fumed silica and / or fumed silica dispersions, associative thickeners such as hydrophobically modified ethoxylated urethanes (HEUR), hydrophobically modified alkali-swellable emulsion (HASE) polymers, and hydrophobically modified HEC (HMHEC) polymers, anionic polyvalent thickeners such as acrylic polymer emulsions (ASE), and others.

[0025] The disclosed compositions have properties and specifications desirable in the compositions used for coating of metal substrates, such as viscosity. For example, the disclosed water-based coating compositions can have a viscosity in the range of about 15 to 150 seconds, measured at 23 °C, when measured with a 4 mm cup according to DIN EN ISO 2431.

[0026] The properties and advantages of the disclosed compositions can be described in reference to quantitative values determined by various testing procedures and protocols. Some of the tests and protocols, which can be also referred to as “norms,” reference DIN numbers for the standards published by Deutsches Institut fur Normung e. V. (German Institute for Standardization), Berlin, Germany. Some other tests and protocols reference ASTM numbers published by ASTM International (USA). Accordingly, the standards are described in corresponding publications by Deutsches Institut fur Normung e. V. or ASTM International. For example, surface gloss of the coating can be determined by measuring specular reflection using a gloss meter. The gloss of the coating formed by a composition as disclosed herein can be in the range of 1 to 80 units gloss, measured under a 60° angle usingnorm DIN EN 13523-2 assay. Flexibility of the coating can be assessed by using DIN EN 13523-7, an assay of folding T, which is a method of evaluating the flexibility and adhesion of an organic coating on a metallic substrate by observing the cracking or loss of adhesion, when a coated test panel is bent. In the assay of folding T, the coatings formed by the disclosed compositions can exhibit performance in the range of 0-3 T. After ageing the organic coating on the metallic substrate at a temperature of about 80 °C, coatings formed by the disclosed compositions can exhibit performance in the range of 0-3.0 T.

[0027] Resistance to abrasion can be evaluated by a Taber test, using norm DIN EN 13523-16, which measures the weight and thickness loss of the coating after 1000, 2000, 3000 or other number of specified turns (cycles) of two bearing wheels of CS-10 type, with a 500 g weight applied to each wheel. On the Taber test, the coatings formed by the disclosed compositions can exhibit abrasion resistance of < 30 mg for 1000 turns. In some examples, the coatings formed by the disclosed compositions can exhibit abrasion resistance of < 20 mg for 1000 turns. UV resistance is determined by exposing the coatings to different types and levels of UV radiation, using norm DIN EN 13523-10. For example, UV-A and UV-B resistance tests can be performed, during which the sample is exposed to 341 nm UV radiation for UV-A resistance testing and to 313 nm UV radiation for UV-B resistance testing, in two different tests, for 4 hours at a temperature of 60 °C and ambient humidity, then for 4 hours with 100% relative humidity at 40 °C. Coatings formed by the disclosed compositions can exhibit UV resistance of at least 10% gloss left after 2000 hours UV-A. Coatings according to some examples can exhibit at least 10% gloss left after 1000 hours of UV-B exposure.

[0028] Relative hardness can be evaluated by a pencil adhesion test, using norm DIN EN 13523-4, which measures the relative hardness of a coating on a metallic substrate by means of pencils of a known hardness. On the pencil adhesion test, coatings formed by the disclosed compositions can exhibit a relative hardness of HB to 6H. In some examples, the disclosed compositions can exhibit a hardness of 3H. Comparative coatings that are organic solventbased can exhibit a relative hardness of F.

[0029] Adhesive strength can be evaluated by a cross cut test, using norm DIN EN ISO 2409:2020, which measures the resistance of coatings to separation from substrates when a right-angle lattice pattern is cut into the coating and the cut lattice pattern penetrates to the substrate. On the cross cut test, coatings formed by the disclosed compositions can exhibit a cross cut rating of GT 0 to GT 3, correlating to good adhesion of the coatings to a substrate.

[0030] Resistance to cracking and / or pick off on rapid deformation of a coating on a metallic substrate can be evaluated by an impact test, using norm DIN EN 13523-5, which measures the energy the coating will withstand when the coated substrate undergoes an impact of a 1 kg weight dropped onto the coated substrate from a height prescribed per DIN EN 13523-5. Coatings formed by the disclosed compositions pass the impact test.

[0031] Adhesion after indentation can be evaluated by an Erichsen cupping test, using norm DIN EN 13523-6, which measures the adhesion of a coating to a metallic substrate after indentation produced by slow deformation. Coatings formed by the disclosed compositions have an indentation value of 0 to 8.5 millimeters.

[0032] Curing can be evaluated by a rubbing test, using norm DIN EN 13523-11, which measures the resistance of a cured coating, applied to a metallic substrate, to a specific organic solvent (such as methyl ethyl ketone (MEK)). Coatings formed by the disclosed compositions have a rubbing test value of 0 to 100DR (DR refers to “double rubs”).

[0033] Resistance to corrosion can be evaluated by an acetic acid salt spray test (AASS), using norm DIN EN 13523-8, which measures corrosion resistance of a coating applied to a metallic substrate under an accelerated and controlled corrosive environment. Coatings formed by the disclosed compositions have an AASS test value of G1 (mild) to G2, and 1 (S 1 ) to 3(S3).

[0034] Coating thickness can be evaluated by a film thickness test, using norm DIN EN 13523-1, which measures the thickness of a coating applied to a metallic substrate. Coatings formed by the disclosed compositions have a film thickness of 1 - 25 pm.

[0035] The disclosed compositions based on water have a number of advantages compared to traditional organic solvent-based coating compositions. For example, faster line speeds on an industrial coil coating line can be used to dry water-based compositions than can be used for organic solvent-based compositions, because water-based compositions will not create an explosive gas in the drying oven at faster line speeds, unlike organic-solvent based compositions. Utilizing water as the solvent for the disclosed compositions allows for reduced drying time of the coating layer after application compared to organic solvent-based coating compositions. The reduction in drying time in turn increases the efficiency of the coating process. For example, an industrial coil coating line can experience a 35% increase in processing speed if a water-based coating composition as disclosed herein is substituted for an organic solvent-based coating product.

[0036] The compositions disclosed herein exhibit improved adhesion to aluminum substrate, which allows such compositions to be applied directly to aluminum substrate,degreased and pretreated with a chromium pretreatment or with a chromium-free pretreatment. The disclosed compositions can be applied directly on such a substrate as a one-layer coating. The compositions can also be applied over a primer or a base coat to form a top coat.Processes of making

[0037] Also disclosed are exemplary methods and processes of obtaining or making the improved water-based, polyamide and polyurethane containing coating compositions. In the disclosed processes of making, synthetic polymer binders are mixed with other components (such as additives) using normal stirring with a disperser. Water and solvent are then added. PA powder is introduced last and is added by a normal stirring dispersion process, such as those typically used by paint producers.Processes of using and the resulting products

[0038] Also disclosed are exemplary methods and processes related to uses of improved water-based synthetic polymer coating compositions, as well as the products obtained by using improved water-based, polyamide- and polyurethane-containing coating compositions. The improved coating compositions are used for treating, such as coating or painting, of metal surfaces or substrates. Accordingly, methods or processes of using the disclosed coating compositions can be referred to as methods or processes for coating, treating, or painting, or as corresponding uses. The improved coating compositions can be employed for various reasons, for example, for protection, to improve appearance, to improve anticorrosion resistance, or for other reasons. The methods and processes related to using the improved coating compositions are not intended to be limited by the above reasons or results obtained, unless specifically stated.

[0039] The term “metal surface” as used herein generally means an outer part of a quantity of a metal, such as an aluminum alloy, or a metal substrate, article or object. The term “metal substrate” is intended to encompass any surface, object, material or article that can be treated, such as covered, painted, or coated, by the improved water-based coatings of the present invention. The terms “metal substrate” or “metal surface” are not intended to be limited by the type of the metal employed. The metal surfaces or substrates suitable for treatment by the improved water-based coating can be comprised of aluminum alloyed with various elements, such as Si, Mg, Cu etc., as well as the surfaces or substrates comprised of substantially pure aluminum. In this case, the metal surface or substrate can be referred to “aluminum alloy surface,” “aluminum alloy substrate,” “aluminum surface,” “aluminumsubstrate” or other related terms. The terms “aluminum surface,” “aluminum substrate” or other related terms are not intended to be limited by the type of an aluminum employed, whether the aluminum is alloyed or unalloyed. The disclosed coating compositions can also be used on steel substrate.

[0040] Non-limiting examples of metal substrates treated by the improved coating compositions are metal sheets, including coiled metal sheets not subjected to further cutting and forming; metal sheets formed by cutting and optionally other forms of shaping (such as punching, stamping or pressing); substantially flat or three-dimensionally shaped metal panels; metal articles or objects (including articles or objects assembled from or including metal sheets and / or panels). More generally, metal substrates treated by the improved coating compositions encompass metal surfaces or articles and other products or parts including metal surfaces. A metal substrate, such as the examples discussed above, can include components other than or in addition to those specifically discussed, including non- metal components. One example of a metal substrate is a roller shutter, which can also be referred to as a roll shutter, roll-down shutter, or other related terms. These and related terms generally refer to curtain-like structures comprised of aluminum panels or profiles, which can be roll-formed or extruded. An example of a roller shutter (100) is illustrated in FIG. 1A-1B. In addition to aluminum panels (110), roller shutters may include other components, including non-metal components, such as insulation (120). Roller shutters can be installed in window and door openings, or other types of openings, for protection, insulation, and other purposes. For example, roller shutters can be installed for break-in protection, protection from view, sun protection, weather protection, noise protection, temperature or light control, etc. Either roller shutters or the panels of roller shutters can be described as “substrate.” Other examples of metal substrates include parts or panels used in machinery (such as parts or panels for motor vehicles, ships, or aircraft); parts or panels used in appliances, kitchen equipment, hardware, laboratory equipment, or industrial equipment; electronic housing parts; construction parts; architectural parts or panels; parts or panels used in garage doors; parts or panels used in window frames; or parts or panels used in any other suitable application. For example, the improved water-based coatings can be used for treating architectural panels, such as siding, or whole facade coverings. The term “metal substrate,” including “aluminum substrate,” can encompass a wide range of articles, objects or products and can be of any size or thickness. A substrate may have any thickness, for example, a thickness from about 0.1 mm to 4 mm (0.1, 0.5, 1.0 1.5, 2.0, 2.5, 3.0, 3.5, 4.0 mm). Moreover, metal substrates coated with the improved coating compositions can be used in awide range environments or conditions, including temperature and humidity ranges, and can be used in indoor as well as outdoor conditions.

[0041] The terms “substrate” or “surface” can denote a treated or untreated metal substrate or surface. These and related terms can also denote a substrate or surface before, after, or during treatment. Furthermore, various types of treatments and coatings can be used in or applied onto substrates or surfaces in addition to the improved water-based coatings. Other treatments and coatings can be applied before, after, or in between the applications of the improved water-based coatings. For example, the metal substrate or surface can be subjected to degreasing, smoothing, texturizing, sanding, sand-blasting, etching, priming, painting, varnishing, or other treatments. One or more of each of the following may be applied to a substrate: a pre-treatment coating, a primer, a paint coating, a clear coating, or a varnish. An example of an aluminum substrate with several coatings is schematically illustrated in FIG. 2. In FIG. 2, an aluminum substrate (210) is coated with a pretreatment coating (220) that may include chromium or may be chromium -free. The pretreatment coating (220) is coated with a paint coat (230). The paint coat (230) is coated with a clear coat (240) that may be a polyurethane / polyamide blend.

[0042] Also disclosed are processes of using the improved coating compositions. When the improved coating composition is used for treating a metal substrate, the coating composition is applied onto the metal surface or substrate by various suitable methods and techniques under the conditions leading to formation of the stable coating on the metal substrate. For example, application can be by immersion, brush coating, spraying (spray coating), flow coating, knife coating, or roller coating, which is also known as coil coating.

[0043] The terms “coil coating,” “roller coating” and related terms may be used interchangeably to refer to a continuous automated industrial process for efficiently coating coiled metal sheets before the metal sheets are cut or otherwise formed. Coil coating allows for treatment of the entire surface of the metal sheet, providing tightly-bonded finishes and uniform coating. Coil coated metal surfaces, which can also be called pre-painted, are often more durable and more corrosion-resistant than metal surfaces painted after forming or shaping (post-painted metal). Coil coating process can be generally described as follows, although variations or deviations from the below non-limiting description are possible. An industrial coil coating line (300) is schematically illustrated in FIG. 3A. During coil coating, a metal substrate, such a steel or aluminum sheet is provided in a form of a coiled strip (310), which can be also described as coiled sheet or coil. The metal coil (310) is positioned at the beginning of the coating line (300), which may include, but is not limited to, an uncoiler(320), an entrance accumulator (330), a pretreatment area (340) for cleaning and / or conversion coating, a drier (350), a prime coater (360), a curing oven (370), a top coater (380), a finish cover (390), a water quench bath (400), an exit accumulator (410), a cut-off (420), an a recoiler (430). In one continuous process, the coil is unwound, cleaned, treated, primed, and painted before being recoiled on the other end and packaged for shipment. A coil coating line can process metal sheet at a high speed, for example, at least 120 m / min, up to 200 m / min, up to 300 m / min, or greater than 300 m / min. A coil coating process can include a combination of some or all of the following or related steps: attaching the metal sheet entering the line to the previous sheet in the line, which can be referred to as “stitching”; unwinding (uncoiling) the coil; flattening the strip; cleaning the strip; pre-treating the metal substrate with chemicals; drying; applying a primer or a base coat on one or both sides of the metal strip; one or more curing steps; cooling; applying one or more layers of coating; cooling; and rewinding of the coated sheet. The above steps are not intended to be limiting, and other (or fewer) steps may be involved.

[0044] The specific steps and conditions involved in a coil coating process are determined by various factors, such as the type of a coil coating equipment, the type of coating, and / or the type of a metal substrate being coated. For example, an aluminum substrate subjected to a coil coating process may need to be degreased and / or cleaned prior to application of any coatings. A pretreatment coating can then be applied to improve a bond between the metal and subsequent coatings, in addition to improving corrosion resistance. Chromium or titanium based products may be used as pre-treatments. After pretreatment, an aluminum substrate is dried, and then may be subjected to application of primers, for example, by rollers, on one or both sides of the substrate. The primer on the aluminum substrate can then be cured in an oven at a high temperature, for example, 150-280 °C, for an appropriate time, for example, 5-100 seconds. Upon exiting the oven, the aluminum substrate is cooled, for example, by air and / or water. A coating composition is then applied, and then cured in a curing oven, as schematically illustrated in FIG. 3B. FIG. 3B illustrates rollers (440) applying a liquid coating (450) to metal strip (460). The coated aluminum sheet then passes through a curing oven (470). The substrate is subsequently cooled. Thus, the coil coating processes and lines that involve application of several coatings or coating layers require a corresponding number of coating rooms and ovens and a corresponding number of coating application steps and curing steps. After application of the top coat, the aluminum substrate can be additionally printed, striped and embossed to create special visual effects. After the treatment, the aluminum substrate may be recoiled and / or further processed, forexample, by cutting. While the above-described process steps are applicable to the treatment of aluminum substrate, they can also be adapted to the treatment of other substrates, such as steel.

[0045] As discussed earlier, utilizing water as the solvent for the disclosed compositions allows for reduced drying time of the coating layer after application compared to organic solvent-based coating compositions. The reduction in drying time in turn increases the efficiency of the coating process. For example, an industrial coil coating line (discussed in more detail below) can experience a 35% increase in processing speed if a water-based coating composition as disclosed herein is substituted for an organic solvent-based coating product.

[0046] The reduction in drying and / or curing time or temperature in turn increases the speed coating process. For example, an industrial coil coating line (discussed in more detail below) can experience a 30-35% increase in processing speed, which can achieve a speed of 120-200 m / min, if a water-based coating composition as disclosed herein is substituted for an organic solvent-based coating product. Curing time of the coating compositions described in can be from 5 to 100 seconds with a Peak Metal Temperature (PMT) varying from 150 °C to 250 °C.Illustrations of Suitable Compositions, Processes, and Substrates

[0047] Illustration 1 is a coating composition comprising one or more synthetic polymer binders, a cross-linker, a pigment, a wetting additive, a dispersing additive, and up to 50 wt. % dry weight of a polyamide.

[0048] Illustration 2 is the coating composition of any preceding or subsequent illustration, further comprising up to 80 wt. % water and one or more organic solvents.

[0049] Illustration 3 is the coating composition of any preceding or subsequent illustration, wherein the one or more synthetic polymer binders comprises a polyurethane and a polyester.

[0050] Illustration 4 is the coating composition of any preceding or subsequent illustration, comprising 20-60 wt. % dry weight of the one or more synthetic polymer binder.

[0051] Illustration 5 is the coating composition of any preceding or subsequent illustration, comprising up to 5 wt. % dry weight of the polyamide.

[0052] Illustration 6 is the coating composition of any preceding or subsequent illustration, comprising 0.1-60 wt. % dry weight of the pigment.

[0053] Illustration 7 is the coating composition of any preceding or subsequent illustration, having a dry weight ratio of the polyamide to the synthetic polymer binder from l:10 to 1 :3.

[0054] Illustration 8 is the coating composition of any preceding or subsequent illustration, wherein no polyamide is present in the composition.

[0055] Illustration 9 is the coating composition of any preceding or subsequent illustration, wherein the cross-linker comprises one or more polyisocyanates, blocked polyisocyanates, or combinations thereof.

[0056] Illustration 10 is the coating composition of any preceding or subsequent illustration, further comprising an epoxy from 0.1 to 10 wt. % dry weight.

[0057] Illustration 11 is the coating composition of any preceding or subsequent illustration, further comprising one or more defoaming additives, rheology additives, or combinations thereof.

[0058] Illustration 12 is the coating composition of any preceding or subsequent illustration, having a viscosity of 15-150 seconds measured with 4 mm ISO cup at 23 °C.

[0059] Illustration 13 is a substrate comprising a coating layer formed from the coating composition of any preceding or subsequent illustration.

[0060] Illustration 14 is a substrate of any preceding or subsequent illustration, wherein the coating layer is dry and comprises a thickness of 1-25 pm.

[0061] Illustration 15 is a substrate of any preceding or subsequent illustration, wherein the coating layer has a gloss level of 1-80 gloss units.

[0062] Illustration 16 is a substrate of any preceding or subsequent illustration, wherein the substrate comprises a metal.

[0063] Illustration 17 is a substrate of any preceding or subsequent illustration, wherein the metal comprises aluminum.

[0064] Illustration 18 is a process of applying a coating to a substrate comprising applying a composition comprising one or more synthetic polymer binders, a cross-linker, a wetting additive, a dispersing additive, and up to 50 wt. % dry weight of a polyamide to an aluminum substrate and drying the composition to produce a coated aluminum substrate.

[0065] Illustration 19 is the process of any preceding or subsequent illustration, wherein the substrate is an uncoiled aluminum sheet.

[0066] Illustration 20 is the process of any preceding or subsequent illustration, wherein the step of drying is conducted at a Peak Metal Temperature of 150 to 250 °C for 5-100 seconds.

[0067] The following examples are for illustration only without constituting any limitation thereof. Various embodiments, modifications and equivalents thereof which, after reading the description herein, may suggest themselves to those skilled in the art without departing from the spirit of the invention.EXAMPLE 1

[0068] Preparation of Water Based Coating Compositions of Different Colors. Waterbased coating compositions of gray, beige, white, brown, metallic 1, metallic 2, and anthracite were prepared according to the formulations illustrated in Table 2, which shows the various components in weight percent of the final composition weight.

[0069] The compositions were prepared and mixed at room temperature (15-35 °C). The components of the formulations were added in the order listed in Table 2. Only short to average stirring duration (e.g., 15 minutes at 10-20 m / s) was necessary to sequentially incorporate the raw materials.

[0070] The components employed in the laboratory formulations and listed in Table 2 were provided as follows. Polyurethane 1 was provided as a waterborne dispersion of aliphatic polyurethane based on carbonate from a supplier. Blocked Polyisocyanate 1, 2, and 3 were provided as three water-based blocked isocyanates from two different suppliers. Polyester 1 and 2 were provided as two different polyesters. Epoxy 1 was provided as a solid epoxy resin emulsion in water. Defoaming Agent 1 was a water-based defoaming additive with wetting properties that was free from silicon and mineral oils. Defoaming Agent 2 was a polymer-based defoamer. Light Stabilizers 1 and 2 were hindered amine light stabilizers. Polyamide 1 was PA 11. Organic Solvent 1 was a high boiling point solvent compatible with water (e.g., butyl glycol). Thickening Agent 1 was an acrylic copolymer emulsion (ASE). Pigments were provided from four different suppliers. Wetting and Dispersing Additive 1 was an anionic wetting and dispersing additive.

[0071] Examples of suitable isocyanates include, but are not limited to, hexamethylene diisocyanate; 2,2,4-trimethyl-l,6-hexane diisocyanate; cyclohexyl-l,4-diisocyanate; isophorone diisocyanate; dicyclohexylmethane-4-4’-diisocyanate; l,3,5-trimethyl(2,4-co- diisocy anatom ethyl) benzene; toluene diisocyanate; and diphenylmethane-4, 4’ -diisocyanate. Examples of suitable polyurethanes are the adduct of one molecule of 1,4-butanediol and two molecules of isophorone diisocyanate or hexamethylene diisocyanate, dicyclohexylmethane- 4,4’-diisocyanate, 1,3, 5 -trimethyl (2,4-co-diisocyanatmethyl) benzene, toluene diisocyanate, with diphenylmethane-4, 4’-diisocyanate etc. Hydroxyl-functional binders react with theisocyanate groups of the blocked di- or polyisocyanate, for example. Suitable polyamides include, but are not limited to polyamide 6, 11, and 12. Suitable defoaming agents include, but are not limited to, polyglycol emulsions. Suitable thickening agents include, but are not limited to, hydrophobically modified ethoxylated urethanes (HEUR), hydrophobically modified alkali-swellable emulsion (HASE) polymers, and hydrophobically modified HEC (HMHEC) polymers, anionic polyvalent thickeners such as acrylic polymer emulsions (ASE). Suitable wetting additives include, but are not limited to organic surfactants, ionic polyacrylates, succinic acids modified with esters (e.g., succinate esters), and fatty alcohol alkoxylates. Suitable dispersing additives include, but are not limited to, polycarboxylates and polyphosphates. Suitable additives having wetting and dispersing properties include, but are not limited to, polymeric phosphoric acid esters, alkyl ammonium salts, modified polyacrylates, and modified polyethers. Suitable organic solvents include, but are not limited to, butyl glycol, butyl di glycol, 2-butanol, ethanol, and 1 -propanol.Table 2. FormulationsEXAMPLE 2

[0072] Preparation of Pigment Paste and Grinding Formulations. Pigment paste and grinding formulations of anthracite colored coating compositions were prepared according to the formulations illustrated in Table 3, which shows the various components in weight percent of the final composition weight. Pigment paste formulations were prepared as described in Example 1. The pigment grinding formulations were also prepared according to Example 1, and a grinding mill was used to grind the pigments for those formulations.Table 3. Exemplary Anthracite Color Coating CompositionsEXAMPLE 3

[0073] Laboratory formulation and testing of the coating compositions. Water-based Example 1, prepared according to the compositions disclosed herein, and organic solventbased Comparative Example 1, were applied on aluminum substrates previously washed, cleaned pretreated. The formulations were applied onto the substrate with a bar coater, then cured in the oven to reach a PMT of 150 to 250 °C. Upon curing, the coating was tested to measure various properties such as thickness, flexibility, abrasion, corrosion resistance, and others. The results of these tests are summarized in Tables 4 and 5.

[0074] Example 1 exhibited similar or improved properties in comparison to organic solvent-based Comparative Example 1. For example, both samples exhibited adhesion in the cross cut test of GT0; god flexibility of 0.5 T in the T-Bend test; 1.0 T in the T-Bend test after ageing; similar corrosive resistance of G1 in the AASS test; abrasion resistance of less than 10 mg after 1000 Taber turns; cure of 100 DR after the rubbing test; and an adhesion of 1 in the Erichsen cupping test. Example 1 exhibited a larger relative hardness in the pencil adhesion test of 3H compared to Comparative Example 1, which exhibited a relative hardnessof F. Example 1 exhibited a coating thickness of 6.5 + 8 pm, whereas Comparative Example 1 exhibited a coating thickness of 8 + 11 pm.Table 4.Table 5.

[0075] All patents, patent applications, publications, and abstracts cited above are incorporated herein by reference in their entirety. Various embodiments of the invention have been described in fulfillment of the various objectives of the invention. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations thereof will be readily apparent to those of skill in the art without departing from the spirit and scope of the invention as defined in the following claims.

Claims

WHAT IS CLAIMED IS:

1. A coating composition comprising one or more synthetic polymer binders, a crosslinker, a pigment, a wetting additive, a dispersing additive, and up to 50 wt. % dry weight of a polyamide.

2. The coating composition of claim 1, further comprising up to 80 wt. % water and one or more organic solvents.

3. The coating composition of claim 1 or 2, wherein the one or more synthetic polymer binders comprises a polyurethane and a polyester.

4. The coating composition of any one of claims 1-3, comprising: a) 20-60 wt. % dry weight of the one or more synthetic polymer binder; b) up to 5 wt. % dry weight of the polyamide; c) 0.1-60 wt. % dry weight of the pigment; or d) combinations thereof.

5. The coating composition of any one of claims 1-4, having a dry weight ratio of the polyamide to the synthetic polymer binder from 1 : 10 to 1 :3.

6. The coating composition of any one of claims 1-5, wherein no polyamide is present in the composition.

7. The coating composition of any one of claims 1-6, wherein the cross-linker comprises one or more polyisocyanates, blocked polyisocyanates, or combinations thereof.

8. The coating composition of any one of claims 1-7, further comprising an epoxy from 0.1 to 10 wt. % dry weight.

9. The coating composition of any one of claims 1-8, further comprising one or more defoaming additives, rheology additives, or combinations thereof.

10. The coating composition of any one of claims 1-9, having a viscosity of 15-150 seconds measured with 4 mm ISO cup at 23 °C.

11. A substrate comprising a coating layer formed from the coating composition of any one of claims 1-10.

12. The substrate of claim 11, wherein the coating layer is dry and comprises a thickness of 1-25 pm.

13. The substrate of claim 11 or 12, wherein the coating layer has a gloss level of 1-80 gloss units.

14. The substrate of any of claims 11-13, wherein the substrate comprises a metal, preferably aluminum.

15. A process of applying a coating to a substrate, preferably an uncoiled aluminum sheet, the process comprising applying a composition comprising one or more synthetic polymer binders, a cross-linker, a wetting additive, a dispersing additive, and up to 50 wt. % dry weight of a polyamide to an aluminum substrate and drying the composition to produce a coated aluminum substrate, preferably wherein the step of drying is conducted at a Peak Metal Temperature of 150 to 250 °C for 5-100 seconds.

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