Patent Application
20240167164
The present invention relates to compositions, systems, and methods for treating a substrate.
The use of protective coatings on metal substrates for improved corrosion resistance and paint adhesion is common. Conventional techniques for coating such substrates include techniques that involve pretreating the metal substrate with chromium-containing compositions. The use of such chromate-containing compositions, however, imparts environmental and health concerns.
Disclosed herein is a composition comprising a first lanthanide series metal, wherein the composition has a pH of less than 2.0 and is substantially free, or essentially free, or completely free of peroxide
Also disclosed herein is a composition comprising a first lanthanide series metal and at least one of a second lanthanide series metal, copper, an inorganic phosphate compound, an organophosphate compound, and an organophosphonate compound; wherein the composition is substantially free, essentially free, or completely free of peroxide.
Also disclosed herein is a system for treating a metal substrate, comprising: a first composition comprising a first lanthanide series metal, wherein the composition has a pH of less than 2.0 and is substantially free, or essentially free, or completely free of peroxide; and a second composition comprising a fluorometallic acid and having a pH of 1.0 to 4.0; and/or a third composition comprising a Group IVB metal.
Also disclosed herein is a system for treating a metal substrate, comprising: a first composition comprising a first lanthanide series metal and at least one of a second lanthanide series metal, copper, an inorganic phosphate compound, an organophosphate compound, and an organophosphonate compound; wherein the composition is substantially free, essentially free, or completely free of peroxide; and a second composition comprising a fluorometallic acid and having a pH of 1.0 to 4.0; and/or a third composition comprising a Group IVB metal.
Also disclosed herein are methods of treating a metal substrate comprising contacting at least a portion of a surface of the substrate with a composition comprising a first lanthanide series metal, wherein the composition has a pH of less than 2.0 and is substantially free, or essentially free, or completely free of peroxide.
Also disclosed herein are methods of treating a metal substrate comprising contacting at least a portion of a surface of the substrate with a composition comprising a first lanthanide series metal and at least one of a second lanthanide series metal, copper, an inorganic phosphate compound, an organophosphate compound, and an organophosphonate compound; wherein the composition is substantially free, essentially free, or completely free of peroxide.
Also disclosed herein is a treated substrate comprising a surface, wherein at least a portion of the surface is treated with one of the systems or methods of the present invention.
Also disclosed herein is a metal substrate comprising a surface at least partially coated with a layer formed from one of the compositions disclosed herein.
For purposes of the following detailed description, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. Moreover, other than in any operating examples, or where otherwise indicated, all numbers such as those expressing values, amounts, percentages, ranges, subranges and fractions may be read as if prefaced by the word “about,” even if the term does not expressly appear. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Where a closed or open-ended numerical range is described herein, all numbers, values, amounts, percentages, subranges and fractions within or encompassed by the numerical range are to be considered as being specifically included in and belonging to the original disclosure of this application as if these numbers, values, amounts, percentages, subranges and fractions had been explicitly written out in their entirety.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard variation found in their respective testing measurements.
As used herein, unless indicated otherwise, a plural term can encompass its singular counterpart and vice versa, unless indicated otherwise. For example, although reference is made herein to “a” lanthanide series metal and “a” fluorometallic acid, a combination (i.e., a plurality) of these components can be used.
In addition, in this application, the use of “or” means “and/or” unless specifically stated otherwise, even though “and/or” may be explicitly used in certain instances.
As used herein, “including,” “containing” and like 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 unrecited elements, materials, ingredients or method steps. As used herein, “consisting of” is understood in the context of this application to exclude the presence of any unspecified element, ingredient or method step. As used herein, “consisting essentially of” is understood in the context of this application to include the specified elements, materials, ingredients or method steps “and those that do not materially affect the basic and novel characteristic(s)” of what is being described.
As used herein, the terms “on,” “onto,” “applied on,” “applied onto,” “formed on,” “deposited on,” “deposited onto,” mean formed, overlaid, deposited, or provided on but not necessarily in contact with the surface. For example, a coating composition “applied onto” a substrate does not preclude the presence of one or more other intervening coating layers of the same or different composition located between the coating composition and the substrate.
As used herein, a “system” refers to a plurality of treatment compositions (including cleaners and rinses) used to treat a substrate and to produce a treated substrate. The system may be part of a production line (such as a factory production line) that produces a finished substrate or a treated substrate that is suitable for use in other production lines. As used herein, reference to a “first composition,” a “second composition,” a “third composition,” etc. is not intended to imply any specific order of treatment but rather is for ease of reference only.
As used herein, a “salt” refers to an ionic compound made up of metal cations and non-metallic anions and having an overall electrical charge of zero. Salts may be hydrated or anhydrous.
As used herein, “aqueous composition” refers to a solution or dispersion in a medium that comprises predominantly water. For example, the aqueous composition may comprise water in an amount of more than 50 wt. %, or more than 70 wt. % or more than 80 wt. % or more than 90 wt. % or more than 95 wt. % based on the total weight of the composition. That is, the aqueous composition may for example consist substantially of water.
As used herein, the term “dispersion” refers to a two-phase transparent, translucent, or opaque system in which metal phosphate particles are in the dispersed phase and an aqueous medium, which includes water, is in the continuous phase.
As used herein, “deoxidizing composition” or “deoxidizer” refers to a composition that etches the metal substrate surface by removing an oxide layer from the surface, wherein such oxide layer may be a passive layer or may be a layer formed as a result of metallurgical processes such as welding, cutting, laser processing, and the like.
As used herein, “deoxidizing bath” refers to an aqueous bath containing a deoxidizing composition and that may contain components that are byproducts of the process.
As used herein, “pretreatment composition” refers to a composition that is capable of reacting with and chemically altering the substrate surface and binding to it to form a film that affords corrosion protection.
As used herein, “pretreatment bath” refers to an aqueous bath containing the pretreatment composition and that may contain components that are byproducts of the process.
As used herein, “seal composition” or “sealing composition” refers to a composition that affects a substrate surface or a material deposited onto a substrate surface in such a way as to alter the physical and/or chemical properties of the substrate surface (i.e., the composition affords corrosion protection).
As used herein, “seal bath” or “sealing bath” refers to an aqueous bath containing the seal composition and that may contain components that are byproducts of the process.
As used herein, the terms “Group IIIA metal” and “Group IIIA element” refer to an element that is in group IIIA of the CAS version of the Periodic Table of the Elements as is shown, for example, in the Handbook of Chemistry and Physics, 63rd edition (1983), corresponding to Group 13 in the actual IUPAC numbering.
As used herein, the term “Group IIIA metal compound” refers to a compound that includes at least one element that is in Group IIIA of the CAS version of the Periodic Table of the Elements.
As used herein, the terms “Group IVA metal” and “Group IVA element” refer to an element that is in group IVA of the CAS version of the Periodic Table of the Elements as is shown, for example, in the Handbook of Chemistry and Physics, 63rd edition (1983), corresponding to Group 14 in the actual IUPAC numbering.
As used herein, the terms “Group IVA metal compound” refer to compounds that include at least one element that is in Group IVA of the CAS version of the Periodic Table of the Elements.
As used herein, the terms “Group IVB metal” and “Group IVB element” refer to an element that is in group IVB of the CAS version of the Periodic Table of the Elements as is shown, for example, in the Handbook of Chemistry and Physics, 63rd edition (1983), corresponding to Group 4 in the actual IUPAC numbering.
As used herein, the term “Group IVB metal compound” refers to compounds that include at least one element that is in Group IVB of the CAS version of the Periodic Table of the Elements.
As used herein, the terms “Group VIIIB metal” and “Group VIIIB element” refer to an element that is in group VIIIB of the CAS version of the Periodic Table of the Elements as is shown, for example, in the Handbook of Chemistry and Physics, 63rd edition (1983), corresponding to Groups 8-10 in the actual IUPAC numbering.
As used herein, the term “Group VIIIB metal compound” refers to compounds that include at least one element that is in Group VIIIB of the CAS version of the Periodic Table of the Elements.
As used herein, the term “halogen” refers to any of the elements fluorine, chlorine, bromine, iodine, and astatine of the CAS version of the Periodic Table of the Elements, corresponding to Group VIIA of the periodic table.
As used herein, the term “halide” refers to compounds that include at least one halogen.
As used herein, a “coating composition” refers to a composition, e.g., a solution, mixture, or a dispersion, that, in an at least partially dried or cured state, is capable of producing a film, layer, or the like on at least a portion of a substrate surface.
As further defined herein, ambient conditions generally refer to room temperature and humidity conditions or temperature and humidity conditions that are typically found in the area in which the coating composition is being applied to a substrate, e.g., at 10° C. to 40° C. and 5% to 80% relative humidity, while slightly thermal conditions are temperatures that are slightly above ambient temperature (e.g., >40° C. and less than 100° C. at 5% to 80% relative humidity).
As used herein, unless indicated otherwise, the term “substantially free” means that a particular material is only present in a mixture or a composition (or a coating, film or layer formed therefrom) in an amount of less than 5 parts per million (ppm) based on total weight of the mixture or composition (or coating, film, or layer formed therefrom). As used herein, unless indicated otherwise, the term “essentially free” means that a particular material is only present in a mixture or a composition (or a coating, film or layer formed therefrom) in an amount of less than 1 ppm based on total weight of the mixture or composition (or coating, film, or layer formed therefrom). As used herein, unless indicated otherwise, the term “completely free” means that a particular material is only present in a mixture or a composition (or a coating, film or layer formed therefrom) in an amount of less than 1 part per billion (ppb) based on total weight of the mixture or composition (or coating, film, or layer formed therefrom) or that such material is below the detection limit of common analytical techniques. When a mixture or a composition (or a coating, film, or layer formed therefrom) is substantially free, essentially free, or completely free of a particular material, this means that such material in any form is excluded from the mixture or composition (or coating, film, or layer formed therefrom), except that such material may unintentionally be present as a result of, for example, carry-over from prior treatment baths in the processing line, contamination from a substrate, or the like.
As used herein, a “system” refers to a plurality of treatment compositions (including cleaners and rinses) used to treat a substrate and to produce a treated substrate. The system may be part of a production line (such as a factory production line) that produces a finished substrate or a treated substrate that is suitable for use in other production lines. As used herein, reference to a “first pretreatment composition,” a “second pretreatment composition”, and a “third pretreatment composition” is not intended to imply any specific order of treatment but rather is for ease of reference only.
Unless otherwise disclosed herein, as used herein, the terms “total composition weight”, “total weight of a composition” or similar terms refer to the total weight of all ingredients being present in the respective composition including any carriers and solvents.
Suitable substrates that may be used include metal substrates, metal alloy substrates, and/or substrates that have been metallized, such as nickel-plated plastic. The metal or metal alloy can comprise or be steel, aluminum, zinc, and/or nickel. For example, the steel substrate could be cold rolled steel, hot rolled steel, electrogalvanized steel, and/or hot dipped galvanized steel. Aluminum alloys of the 1XXX, 2XXX, 3XXX, 4XXX, 5XXX, 6XXX, or 7XXX series as well as clad aluminum alloys also may be used as the substrate. Aluminum alloys may comprise, for example, 0.01% by weight copper to 10% by weight copper. Aluminum alloys which are treated may also include castings, such as 1XX.X, 2XX.X, 3XX.X, 4XX.X, 5XX.X, 6XX.X, 7XX.X, 8XX.X, or 9XX.X (e.g., A356.0). The substrate used may also comprise titanium and/or titanium alloys, zinc and/or zinc alloys, and/or nickel and/or nickel alloys. In examples, the substrate may be substantially free of magnesium. Suitable substrates for use in the present invention include those that are often used in the assembly of vehicular bodies (e.g., without limitation, door, body panel, trunk deck lid, roof panel, hood, roof and/or stringers, rivets, landing gear components, and/or skins used on an aircraft), a vehicular frame, vehicular parts, motorcycles, wheels, industrial structures and components such as appliances, including washers, dryers, refrigerators, stoves, dishwashers, and the like, personal electronics, agricultural equipment, lawn and garden equipment, air conditioning units, heat pump units, heat exchangers, lawn furniture, and other articles. As used herein, “vehicle” or variations thereof includes, but is not limited to, civilian, commercial and military aircraft, and/or land vehicles such as cars, motorcycles, and/or trucks. The metal substrate also may be in the form of, for example, a sheet of metal or a fabricated part.
In examples, the substrate may be a multi-metal article. As used herein, the term “multi-metal article” refers to (1) an article that has at least one surface comprised of a first metal and at least one surface comprised of a second metal that is different from the first metal, (2) a first article that has at least one surface comprised of a first metal and a second article that has at least one surface comprised of a second metal that is different from the first metal, or (3) both (1) and (2).
In examples, the substrate may comprise a three-dimensional component formed by an additive manufacturing process such as selective laser melting, e-beam melting, directed energy deposition, binder jetting, metal extrusion, and the like. In examples, the three-dimensional component may be a metal and/or resinous component.
The present invention is directed to a first composition comprising, or consisting essentially of, or consisting of, a first lanthanide series metal and being substantially free, or essentially free, or completely free, of peroxide. As discussed in more detail below, the first composition may have a pH of less than 2.0. As discussed in more detail below, the first composition may further comprise at least one of a second lanthanide series metal, copper, an inorganic phosphate compound, an organophosphate compound, and an organophosphonate compound. The first composition may be a pretreatment composition or a seal composition and may be a part of a treatment system as described below. As used herein, “peroxide” refers to a compound having the structure R1—O—O—R2, wherein the oxygen atoms in the O—O group (the “peroxide group”) have an oxidation state of −1 and wherein R1 and R2 may respectively be hydrogen, an inorganic atom, a hydrocarbon, and/or a heteroatom containing a hydrocarbon. R1 and R2 may be the same or different.
The lanthanide series metal may, for example, comprise cerium, praseodymium, terbium, gadolinium, or combinations thereof. For example, the lanthanide series metal may be cerium. In examples, the lanthanide series metal may have an oxidation state of +4.
In examples, the first composition may comprise more than one lanthanide series metal (i.e., a “first” lanthanide series metal and a “second” lanthanide series metal, a “third” lanthanide series metal, etc., wherein the first, second, third, etc. lanthanide series metals differ from each other). In other examples, the first composition may contain no more than one lanthanide series metal, such that the first composition may contain one lanthanide series metal and may be substantially free or essentially free or completely free of more than one lanthanide series metals.
The lanthanide series metal may be present in the first composition as a salt. Thus, the first composition may further comprise an anion that may be suitable for forming a salt with the lanthanide series metal, such as an ammonium nitrate, an ammonium sulfate, a nitrate, a sulfuric acid, and combinations thereof.
Each lanthanide series metal may be present in the first composition in an amount of at least 5 ppm based on total weight of the first composition, such as at least 10 ppm, such as at least 20 ppm, such as at least 30 ppm, such as at least 40 ppm, such as at least 50 ppm, and may be present in the first composition in an amount of no more than 25,000 ppm based on total weight of the first composition, such as no more than 10,000 ppm, such as no more than 5,000 ppm, such as no more than 3,000 ppm, such as no more than 1,000 ppm, such as no more than 500 ppm. Each lanthanide series metal may be present in the first composition in an amount of 5 ppm to 25,000 ppm based on total weight of the first composition, such as 10 ppm to 10,000 ppm, such as 20 ppm to 5,000 ppm, such as 30 ppm to 3,000 ppm, such as 40 ppm to 1,000 ppm, such as 50 ppm to 500 ppm.
The first composition may be substantially free, essentially free, or completely free of lanthanide oxide such that the bath containing the first composition is substantially, essentially, or completely free of lanthanide oxide.
The first composition may further comprise copper. Soluble and insoluble compounds may serve as the source of copper in the first composition. For example, the supplying source of copper ions in the first composition may be a water-soluble copper compound. Specific examples of such materials include, but are not limited to, copper cyanide, copper potassium cyanide, copper sulfate, copper nitrate, copper pyrophosphate, copper thiocyanate, disodium copper ethylenediaminetetraacetate tetrahydrate, copper bromide, copper oxide, copper hydroxide, copper chloride, copper fluoride, copper gluconate, copper citrate, copper lauroyl sarcosinate, copper formate, copper acetate, copper propionate, copper butyrate, copper lactate, copper oxalate, copper phytate, copper tartarate, copper malate, copper succinate, copper malonate, copper maleate, copper benzoate, copper salicylate, copper aspartate, copper glutamate, copper fumarate, copper glycerophosphate, sodium copper chlorophyllin, copper fluorosilicate, copper fluoroborate and copper iodate, as well as copper salts of carboxylic acids in the homologous series formic acid to decanoic acid, copper salts of polybasic acids in the series oxalic acid to suberic acid, and copper salts of hydroxycarboxylic acids, including glycolic, lactic, tartaric, malic and citric acids.
When copper ions supplied from such a water-soluble copper compound are precipitated as an impurity in the form of copper sulfate, copper oxide, etc., it may be desirable to add a complexing agent that suppresses the precipitation of copper ions, thus stabilizing them as a copper complex in the solution.
The copper compound may be added as a copper complex salt such as K3Cu(CN)4 or Cu-EDTA, which can be present stably in the first composition on its own, but it is also possible to form a copper complex that can be present stably in the first composition by combining a complexing agent with a compound that is difficultly soluble on its own. Examples thereof include a copper cyanide complex formed by a combination of CuCN and KCN or a combination of CuSCN and KSCN or KCN, and a Cu-EDTA complex formed by a combination of CuSO4 and EDTA″2Na.
With regard to the complexing agent suitable for complexing with copper, a compound that can form a complex with copper ions can be used; examples thereof include inorganic compounds such as cyanide compounds and thiocyanate compounds, and polycarboxylic acids, and specific examples thereof include ethylenediaminetetraacetic acid, salts of ethylenediaminetetraacetic acid such as dihydrogen disodium ethylenediaminetetraacetate dihydrate, aminocarboxylic acids such as nitrilotriacetic acid and iminodiacetic acid, oxycarboxylic acids such as citric acid and tartaric acid, succinic acid, oxalic acid, ethylenediaminetetramethylenephosphonic acid, and glycine.
Copper may be present in the first pretreatment composition in an amount of at least 2 ppm based on the total weight of the first pretreatment composition, such as at least 4 ppm, such as at least 6 ppm, such as at least 8 ppm, such as at least 10 ppm. Copper may be present in the first pretreatment composition in an amount of no more than 100 ppm based on the total weight of the first pretreatment composition, such as no more than 80 ppm, such as no more than 60 ppm, such as no more than 40 ppm, such as no more than 20 ppm. Copper may be present in the first pretreatment composition in an amount of from 2 ppm to 100 ppm based on the total weight of the first pretreatment composition, such as from 4 ppm to 80 ppm, such as from 6 ppm to 60 ppm, such as from 8 ppm to 40 ppm.
In other examples, the first composition may be substantially free, or essentially free, or completely free, of copper.
In examples, the first composition may be substantially free, or, in some cases, essentially free, or in some cases, completely free of any Group IVB metals.
The first composition may comprise an inorganic phosphate compound. Suitable examples of the inorganic phosphate compound include sodium phosphotungstate, potassium phosphotungstate, calcium phosphotungstate, and combinations thereof.
The phosphate of the inorganic phosphate compound may be present in the first composition in an amount of at least 100 ppm based on a total weight of the first composition, such as at least 250 ppm, such as at least 400 ppm. The phosphate of the inorganic phosphate compound may be present in the first composition may be present in an amount of no more than 50,000 ppm based on a total weight of the first composition, such as no more than 10,000 ppm such as no more than 1,000 ppm. The phosphate of the inorganic phosphate compound may be present in the first composition may be present in an amount of 100 ppm to 50,000 ppm based on a total weight of the first pretreatment composition, such as 250 ppm to 10,000 ppm, such as 400 ppm to 1,000 ppm.
The first composition may comprise an organophosphate compound or an organophosphonate compound such as an organophosphoric acid or an organophosphonic acid. In examples, the organophosphate compound may be a phosphatized epoxy resin. In examples, the organophosphate or organophosphonate compound may be a phosphoric acid ester or a phosphonic acid ester of an epoxy compound.
Suitable phosphoric acids include, but are not limited to, phosphoric acid ester of bisphenol A diglycidyl ether. Suitable phosphonic acids are those having at least one group of the structure:
where R1 comprises an alkyl, an aryl, an alkoxide, an ester, and/or an ether. For example, R1 may be CH2 or O—CO—(CH2)2. Non-limiting examples include 1-hydroxyethyldiene-1,1-diphosphonic acid (HED), carboxyethyl phosphonic acid. Other examples of phosphonic acids include alkyl phosphonic acids where R1 is an alkyl chain ranging from C1 to C6 such as methylphosphonic, ethylphosphonic acid, propylphosphonic acid, butylphosphonic acid, and/or hexylphosphonic acid. Phosphonic acids where R1 is an aryl group such as phenylphosphonic acid may also be used. Examples of alpha-aminomethylene phosphonic acids which may be utilized in the reaction with an epoxy compound to prepare a compound of the invention include:
where R2 comprises an alkyl, an aryl, an alkoxide, an ester, and/or an ether and R3 comprises a hydrogen, an alkyl, an aryl, an alkoxide, an ester, an ether, and/or an epoxy. For example, R2 may comprise CH2PO3H2 and R3 may comprise hydrogen or an alkyl group such as 2-hydroxyethyl, isopropyl, n-propyl, n-butyl, n-hexyl, n-octyl, isononyl, dodecyl, or benzyl. Other examples of alpha-aminomethylene phosphonic acids include examples where R2 and R3 are alkyl groups, such as P-[(dimethylamino)methyl] phosphonic acid and P-[(diethylamino)methyl] phosphonic acid. Other examples of alpha-aminomethylene phosphonic acids with at least three phosphonic acid per molecule include: aminotris(methylenephosphonic acid) where R2 and R3 are CH2PO3H2, ethylenediaminetetrakis(methylenephosphonic acid), i.e., (H2O3PCH2)2N(CH2)2N(CH2PO3H2)2, and diethylenetriaminepentakis(methylphosphonic acid), i.e., [(H2O3PCH2)2N(CH2)2]2NCH2PO3H2.
Alpha-aminomethylene phosphonic acids are generally known compounds and can be prepared utilizing generally known methods. Many alpha-aminomethylene phosphonic acids are available commercially, for example under the Dequest product line available from Italmatch Chemicals (Genoa, Italy). One such example is aminotris(methylenephosphonic acid) is available in an aqueous solution as Dequest 2000.
Suitable epoxy compounds include, but are not limited to, 1,2-epoxy compounds having an epoxy equivalence of at least 1, such as monoepoxides having a 1,2-epoxy equivalent of 1 or polyepoxides having a 1,2-epoxy equivalent of 2 or more. Examples of such epoxy compounds include, but are not limited to, polyglycidyl ethers of polyhydric phenols such as the polyglycidyl ether of 2,2-bis(4-hydroxyphenyl)propane, i.e., bisphenol A, and 1,1-bis(4-hydroxyphenyl)isobutane, monoglycidyl ethers of a monohydric phenol or alcohol such as phenyl glycidyl ether and butyl glycidyl ether, or combinations thereof.
Suitable examples of organophosphonic or organophosphoric resins include, but are not limited to, benzylaminobis(methylenephosphonic) acid ester of bisphenol A diglycidyl ether carboxyethyl phosphonic acid ester of bisphenol A diglycidyl ether and of phenylglycidyl ether and of butyl glycidyl ether; carboxyethyl phosphonic acid mixed ester of bisphenol A diglycidyl ether and butylglycidyl ether; triethoxyl silyl propylaminobis(methylenephosphonic) acid ester of bisphenol A diglycidyl ether and cocoaminobis(methylenephosphonic) acid ester of bisphenol A diglycidyl ether.
The organophosphate or organophosphonate compound may be present in the first composition in an amount of at least 10 ppm based on total weight of the first composition, such as 1,000 ppm, such as at least 10,000 ppm, and may be present in an amount of no more than 100,000 ppm based on total weight of the first composition, such as no more than 75,000 ppm. The organophosphate or organophosphonate compound may be present in the first composition in an amount of 10 ppm to 100,000 ppm based on total weight of the first composition, such as 10,000 ppm to 75,000 ppm.
The organophosphate or organophosphonate compound may be soluble in an aqueous medium (described below) to the extent of at least 0.03 grams per 100 grams of water at 25° C.
The first composition may exclude chromium or chromium-containing compounds. As used herein, the term “chromium-containing compound” refers to materials that include trivalent and/or hexavalent chromium. Non-limiting examples of such materials include chromic acid, chromium trioxide, chromic acid anhydride, dichromate salts, such as ammonium dichromate, sodium dichromate, potassium dichromate, and calcium, barium, magnesium, zinc, cadmium, strontium dichromate, chromium(III) sulfate, chromium(III) chloride, and chromium(III) nitrate. When a first composition or a material deposited on a substrate surface by deposition of the first composition is substantially free, essentially free, or completely free of chromium, this includes chromium in any form, such as, but not limited to, the trivalent and hexavalent chromium-containing compounds listed above.
Thus, optionally, the first compositions and/or material deposited on a substrate surface by deposition of the first composition may be substantially free, may be essentially free, and/or may be completely free of one or more of any of the elements or compounds listed in the preceding paragraph. A first composition or a material deposited on a substrate surface by deposition of the first pretreatment composition that is substantially free of chromium or derivatives thereof means that chromium or derivatives thereof are not intentionally added, but may be present in trace amounts, such as because of impurities or unavoidable contamination from the environment. In other words, the amount of material is so small that it does not affect the properties of the first pretreatment composition or deposited material; in the case of chromium, this may further include that the element or compounds thereof are not present in the first pretreatment compositions and/or deposited material in such a level that it causes a burden on the environment. The term “substantially free” means that the first compositions and/or deposited material contain less than 10 ppm of any or all of the elements or compounds listed in the preceding paragraph based on total weight of the composition or the layer, respectively, if any at all. The term “essentially free” means that the first compositions and/or deposited material contain less than 1 ppm of any or all of the elements or compounds listed in the preceding paragraph, if any at all. The term “completely free” means that the first compositions and/or deposited material contain less than 1 ppb of any or all of the elements or compounds listed in the preceding paragraph, if any at all.
The first composition may, in some instances, exclude phosphate ions or phosphate-containing compounds and/or the formation of sludge, such as aluminum phosphate, iron phosphate, and/or zinc phosphate, formed in the case of using a treating agent based on zinc phosphate. As used herein, “phosphate-containing compounds” include compounds containing the element phosphorous such as ortho phosphate, pyrophosphate, metaphosphate, tripolyphosphate, organophosphonates, and the like, and can include, but are not limited to, monovalent, divalent, or trivalent cations such as: sodium, potassium, calcium, zinc, nickel, manganese, aluminum and/or iron. When a composition and/or a material deposited on a substrate surface by deposition of the first composition is substantially free, essentially free, or completely free of phosphate, this includes phosphate ions or compounds containing phosphate in any form.
Thus, the first composition and/or a material deposited on a substrate surface by deposition of the first composition may be substantially free, or in some cases may be essentially free, or in some cases may be completely free, of one or more of any of the ions or compounds listed in the preceding paragraph. A first composition and/or deposited material is substantially free of phosphate means that phosphate ions or compounds containing phosphate are not intentionally added, but may be present in trace amounts, such as because of impurities or unavoidable contamination from the environment. In other words, the amount of material is so small that it does not affect the properties of the composition; this may further include that phosphate is not present in the first compositions and/or deposited materials in such a level that they cause a burden on the environment. The term “substantially free” means that the first compositions and/or deposited material contain less than 5 ppm of any or all of the phosphate anions or compounds listed in the preceding paragraph based on total weight of the composition or the deposited material, respectively, if any at all. The term “essentially free” means that the first compositions and/or deposited material less than 1 ppm of any or all of the phosphate anions or compounds listed in the preceding paragraph. The term “completely free” means that the first compositions and/or deposited material contain less than 1 ppb of any or all of the phosphate anions or compounds listed in the preceding paragraph, if any at all.
The first pretreatment composition may be substantially free, essentially free, or completely free of gelatin.
The pH of the first composition may be less than 2.0, such as less than 1.9, such as less than 1.8, such as less than 1.7, such as less than 1.6, such as less than 1.5. The pH of the first pretreatment composition may be 1.0 to 2.0, such as 1.5 to 1.9, such as 1.6 to 1.9, and may be adjusted using, for example, any acid and/or base as is necessary. The pH of the first composition may be maintained through the inclusion of an acidic material, including water soluble and/or water dispersible acids, such as nitric acid, sulfuric acid, and/or organic acids, including by way of non-limiting examples, C1-C6 acids, such as formic acid, acetic acid, and/or propionic acid. The pH of the first composition may be maintained through the inclusion of a basic material, including water soluble and/or water dispersible bases, such as sodium hydroxide, sodium carbonate, potassium hydroxide, ammonium hydroxide, ammonia, and/or amines such as triethylamine, methylethyl amine, or mixtures thereof.
The first composition may comprise a carrier, often an aqueous medium, so that the composition is in the form of a solution or dispersion of the lanthanide series metal, such as the lanthanide series metal salt, in the carrier. For example, the first composition may be an aqueous composition. In examples, the solution or dispersion of the first composition may be spontaneously applied or contacted to the substrate surface. For example, the solution or dispersion may be brought into contact with the substrate by any of a variety of known techniques, such as dipping or immersion, spraying, intermittent spraying, dipping followed by spraying, spraying followed by dipping, brushing, or roll-coating. The spontaneously applied solution or dispersion, when applied to the metal substrate, may be at a temperature of 20° C. to 50° C., such as 25° C. to 40° C. For example, the spontaneously applied pretreatment process may be carried out at ambient or room temperature. The contact time is often from 15 seconds to 15 minutes, such as 30 seconds to 10 minutes, such as 1 minute to 5 minutes.
Following the contacting with a first composition disclosed herein, the substrate optionally may be air dried at room temperature or may be dried with hot air, for example, by using an air knife, by flashing off the water by brief exposure of the substrate to a high temperature, such as by drying the substrate in an oven at 15° C. to 200° C. or in a heater assembly using, for example, infrared heat, such as for 10 minutes at 70° C., or by passing the substrate between squeegee rolls.
Following the contacting with a first composition, the substrate optionally may be rinsed with tap water, deionized water, and/or an aqueous solution of rinsing agents in order to remove any residue and then optionally may be dried, for example air dried or dried with hot air as described above, such as by drying the substrate in an oven at 15° C. to 100° C., such as 20° C. to 90° C., or in a heater assembly using, for example, infrared heat, such as for 10 minutes at 70° C., or by passing the substrate between squeegee rolls.
Optionally, prior to the contacting with one of the first compositions of the present invention, the substrate may be treated with one of the second compositions and/or third compositions described below.
The systems and methods of the present invention may further comprise a second composition. The second composition may comprise a fluorometallic acid.
The Group IVA metal may, for example, comprise silicon such as silanes, silicas, silicates, and the like. The Group IVA metal may be provided in the second pretreatment composition in the form of specific compounds of the metals, such as their soluble acids and/or salts. Examples of useful compounds include fluorosilicic acid, ammonium and alkali metal fluorosilicates, and the like, including by way of non-limiting example, hexafluorosilicic acid, hexafluorozirconic acid, hexafluorotitanic acid, hexafluoroferric acid, hexafluoroaluminic acid, or combinations thereof.
The Group IVA metal may be present in the second composition in an amount of at least 10 ppm based on total weight of the second composition, such as at least 50 ppm, such as at least 100 ppm, and may be present in the second composition in an amount of no more than 1,500 ppm based on total weight of the second composition, such as no more than 750 ppm, such as no more than 500 ppm. The Group IVA metal may be present in the second composition in an amount of 10 ppm to 1,500 ppm based on total weight of the second composition, such as 50 ppm to 750 ppm, such as 100 ppm to 500 ppm.
The Group IVB metal may comprise zirconium, titanium, hafnium, or combinations thereof. For example, the Group IVB metal used in the second pretreatment composition may be a compound of zirconium, titanium, hafnium, or a mixture thereof. Suitable compounds of zirconium include, but are not limited to, hexafluorozirconic acid, alkali metal and ammonium salts thereof, zirconium tetrafluoride, ammonium zirconium carbonate, zirconium carboxylates and zirconium hydroxy carboxylates, such as zirconium acetate, zirconium oxalate, ammonium zirconium glycolate, ammonium zirconium lactate, ammonium zirconium citrate, zirconium basic carbonate, and mixtures thereof. Suitable compounds of titanium include, but are not limited to, fluorotitanic acid and its salts. A suitable compound of hafnium includes, but is not limited to, hafnium nitrate.
The Group IVB metal may be present in the second composition in an amount of at least 20 ppm based on total weight of the second composition, such as at least 50 ppm, such as at least 100 ppm, such as at least 200 ppm, such as at least 350 ppm, such as at least 500 ppm. The Group IVB metal may be present in the second composition in an amount of no more than 5,000 ppm based on total weight of the second composition, such as no more than 2,500 ppm, such as no more than 1,750 ppm, such as at least 1,500 ppm, such as at least 1,000 ppm, such as at least 500 ppm. The Group IVB metal may be present in the second composition in a total amount of 20 ppm to 5,000 ppm based on total weight of the second composition, such as 50 ppm to 2,500 ppm, such as 100 ppm to 1,750 ppm, such as 200 ppm to 1,500 ppm, such as 50 ppm to 500 ppm, such as 350 ppm to 2,500 ppm, such as 500 ppm to 1,750 ppm. In some instances, the composition may comprise more than one type of Group IVB metal. In such instances, each type of Group IVB metal may be present in the amounts disclosed above.
The Group IIIA metal may comprise, for example, hexafluoroferric acid and the Group VII metal may comprise, for example, hexafluoroaluminic acid.
The Group IIIA metal may be present in the second composition in an amount of at least 10 ppm based on total weight of the second composition, such as at least 50 ppm, such as at least 100 ppm, and may be present in the second composition in an amount of no more than 1,500 ppm based on total weight of the second composition, such as no more than 750 ppm, such as no more than 500 ppm. The Group IIIA metal may be present in the second composition in an amount of 10 ppm to 1,500 ppm based on total weight of the second composition, such as 50 ppm to 750 ppm, such as 100 ppm to 500 ppm.
The Group VIIIB metal of the fluorometallic acid may be present in the second composition in an amount of at least 100 ppm based on total weight of the second composition, such as at least 250 ppm, such as at least 300 ppm. The Group VIIIB metal of the fluorometallic acid may be present in the second composition in an amount of no more than 3,000 ppm based on total weight of the second composition, such as no more than 1,500 ppm, such as no more than 3,000 ppm. The Group VIIIB metal of the fluorometallic acid may be present in the second composition in a total amount of 100 ppm to 3,000 ppm based on total weight of the second composition, such as 250 ppm to 1,500 ppm, such as 300 ppm to 1,000 ppm.
The second composition may further comprise an anion that may be suitable for forming a salt with any of the Group IVA, Group IVB, Group IIIA and/or Group VIIIB metals described above, such as a silicate (orthosilicates and metasilicates), carbonates, hydroxides, and the like.
A source of free fluoride may be present in the second composition. The free fluoride may be derived from the fluorometallic acid described above (e.g., a compound or complex comprising a Group IIIA metal, Group IVA metal, Group IVB metal, and/or Group VIIIB metal) and/or may be derived from a compound or complex other than the compound or complex comprising the Group IIIA metal, Group IVA metal, Group IVB metal, and/or Group VIIIB metal. That is, the second composition may further comprise fluoride ion. Suitable exemplary sources of free fluoride include hydrofluoric acid, sodium hydrogen fluoride, potassium hydrogen fluoride, ammonium salts of fluoride, and/or acids or salts of tetrafluoroborate. As used herein, “fluoride sources” include monofluorides, bifluorides, fluoride complexes, and mixtures thereof known to generate fluoride ions.
As used herein the amount of fluoride disclosed or reported in the second composition is referred to as “free fluoride,” that is, fluoride present in the second composition that is not bound to metal ions or hydrogen ions, as measured in parts per million of fluoride. Free fluoride is defined herein as being able to be measured using, for example, an Orion Dual Star Dual Channel Benchtop Meter equipped with a fluoride ion selective electrode (“ISE”) available from Thermoscientific, the symphony® Fluoride Ion Selective Combination Electrode supplied by VWR International, or similar electrodes. See, e.g., Light and Cappuccino, Determination of fluoride in toothpaste using an ion-selective electrode, J. Chem. Educ., 52:4, 247-250, April 1975. The fluoride ISE may be standardized by immersing the electrode into solutions of known fluoride concentration and recording the reading in millivolts, and then plotting these millivolt readings in a logarithmic graph. The millivolt reading of an unknown sample can then be compared to this calibration graph and the concentration of fluoride determined. Alternatively, the fluoride ISE can be used with a meter that will perform the calibration calculations internally and thus, after calibration, the concentration of the unknown sample can be read directly.
The second composition optionally may comprise free fluoride. The free fluoride, if present at all, may be present in an amount of at least 1 ppm based on a total weight of the second composition, such as at least 10 ppm, such as at least 25 ppm, such as at least 35 ppm. The free fluoride of the second composition may be present in an amount of no more than 500 ppm based on a total weight of the first composition, such as no more than 200 ppm such as no more than 100 ppm, such as no more than 75 ppm. The free fluoride of the second pretreatment composition may be present in an amount of 1 ppm free fluoride to 500 ppm free fluoride based on a total weight of the second pretreatment composition, such as 10 ppm to 200 ppm, such as 25 ppm to 100 ppm, 35 ppm to 75 ppm.
Copper may be present in the second pretreatment composition in an amount of at least 2 ppm based on the total weight of the second pretreatment composition, such as at least 4 ppm, such as at least 6 ppm, such as at least 8 ppm, such as at least 10 ppm. Copper may be present in the second pretreatment composition in an amount of no more than 100 ppm based on the total weight of the second pretreatment composition, such as no more than 80 ppm, such as no more than 60 ppm, such as no more than 40 ppm, such as no more than 20 ppm. Copper may be present in the second pretreatment composition in an amount of from 2 ppm to 100 ppm based on the total weight of the second pretreatment composition, such as from 4 ppm to 80 ppm, such as from 6 ppm to 60 ppm, such as from 8 ppm to 40 ppm.
The second composition may comprise a hydroxide, such as sodium hydroxide, potassium hydroxide, ammonium hydroxide, magnesium hydroxide, lithium hydroxide, or combinations thereof.
As discussed above with respect to the first composition, the second composition may exclude chromium or chromium-containing compounds. That is, the second composition and/or coatings or layers deposited from the second composition may be substantially free, may be essentially free, and/or may be completely free of such chromium or chromium-containing compounds.
As discussed above with respect to the first composition, the second composition may, in some instances, exclude phosphate ions or phosphate-containing compounds and/or the formation of sludge. That is, the second composition and/or coatings or layers deposited from the second composition may be substantially free, or essentially free, or completely free, of phosphate ions or phosphate-containing compounds.
The pH of the second composition may be at least 1.0, such as at least 2.0, such as at least 2.2, and in some instances may be 4.0 or less, such as 3.5 or less, such as 2.5 or less, such as 2.7 or less. The pH of the second composition may, in some instances, be 1.0 to 4.0, such as 1.0 to 3.5, such as 2.0 to 3.0, such as 2.2 to 2.7, and may be adjusted using, for example, any acid and/or base as is necessary. The pH of the second composition may be maintained through the inclusion of an acidic material, including water soluble and/or water dispersible acids, such as nitric acid, sulfuric acid, and/or phosphoric acid. The pH of the second composition may be maintained through the inclusion of a basic material, including water soluble and/or water dispersible bases, such as sodium hydroxide, sodium carbonate, potassium hydroxide, ammonium hydroxide, ammonia, and/or amines such as triethylamine, methylethyl amine, or mixtures thereof.
The second composition may comprise a carrier, often an aqueous medium, so that the composition is in the form of a solution or dispersion of the fluorometals in the carrier. For example, the second composition may be an aqueous composition. The solution or dispersion may be brought into contact with the substrate by any of a variety of known techniques, such as dipping or immersion, spraying, intermittent spraying, dipping followed by spraying, spraying followed by dipping, brushing, or roll-coating. The solution or dispersion when applied to the metal substrate, may be at a temperature of 20° C. to 50° C., such as 25° C. to 40° C. For example, the second treatment process may be carried out at ambient or room temperature. The contact time is often from 5 seconds to 15 minutes, such as 10 seconds to 10 minutes, such as 15 seconds to 3 minutes.
Following the contacting with one of the second compositions disclosed herein, the substrate optionally may be air dried at room temperature or may be dried with hot air as described above with respect to the first composition.
Following the contacting with one of the second compositions disclosed herein, the substrate optionally may be rinsed with tap water, deionized water, and/or an aqueous solution of rinsing agents in order to remove any residue and then optionally may be dried, for example air dried or dried with hot air as described above with respect to the first composition.
As stated above, the third composition may comprise, or consist essentially of, or consist of, a Group IVB metal. The Group IVB metal may comprise zirconium, titanium, hafnium, or combinations thereof. Suitable compounds of zirconium include, but are not limited to, hexafluorozirconic acid, alkali metal and ammonium salts thereof, ammonium zirconium carbonate, zirconyl nitrate, zirconyl sulfate, zirconium carboxylates and zirconium hydroxy carboxylates, such as hydrofluorozirconic acid, zirconium acetate, zirconium oxalate, ammonium zirconium glycolate, ammonium zirconium lactate, ammonium zirconium citrate, and mixtures thereof. Suitable compounds of titanium include, but are not limited to, fluorotitanic acid and its salts. A suitable compound of hafnium includes, but is not limited to, hafnium nitrate.
The Group IVB metal may be present in the third composition in a total amount of at least 20 ppm metal based on total weight of the third composition, such as at least 50 ppm metal, or, in some cases, at least 70 ppm metal. The Group IVB metal may be present in the third composition in a total amount of no more than 1,000 ppm metal based on total weight of the third composition, such as no more than 600 ppm metal, or, in some cases, no more than 300 ppm metal. The Group IVB metal may be present in the third composition in a total amount of 20 ppm metal to 1,000 ppm metal based on total weight of the third composition, such as from 50 ppm metal to 600 ppm metal, such as from 70 ppm metal to 300 ppm metal. As used herein, the term “total amount,” when used with respect to the amount of Group IVB metal, means the sum of all Group IV metals present in the third composition.
The third composition also may comprise a Group IA metal such as lithium. The source of Group IA metal in the third composition may be in the form of a salt. Non-limiting examples of suitable lithium salts include lithium nitrate, lithium sulfate, lithium fluoride, lithium chloride, lithium hydroxide, lithium carbonate, lithium iodide, and combinations thereof.
The Group I metal may be present in the third composition in an amount of at least 2 ppm based on a total weight of the third composition, such as at least 5 ppm, such as at least 25 ppm, such as at least 75 ppm, and in some instances, may be present in amount of no more than 500 ppm based on a total weight of the third composition, such as no more than 250 ppm, such as no more than 125 ppm, such as no more than 100 ppm. The Group IA metal may be present in the third composition in an amount of 2 ppm to 500 ppm based on a total weight of the third composition, such as 5 ppm to 250 ppm, such as 5 ppm to 125 ppm, such as 5 ppm to 25 ppm.
The third composition may also comprise a Group VIB metal. The source of Group VIB metal in the third composition may be in the form of a salt. Non-limiting examples of suitable molybdenum salts include sodium molybdate, lithium molybdate, calcium molybdate, potassium molybdate, ammonium molybdate, molybdenum chloride, molybdenum acetate, molybdenum sulfamate, molybdenum formate, molybdenum lactate, and combinations thereof.
The Group VIB metal may be present in the third composition in an amount of at least 5 ppm based on a total weight of the third composition, such as at least 25 ppm, such as 100 ppm, and in some instances, may be present in the third composition in an amount of no more than 500 ppm based on total weight of the third composition, such as no more than 250 ppm, such as no more than 150 ppm. The Group VIB metal may be present in the third composition in an amount of 5 ppm to 500 ppm based on total weight of the third composition, such as 25 ppm to 250 ppm, such as 40 ppm to 120 ppm.
The third composition may further comprise an anion that may be suitable for forming a salt with the Group IVB, Group I and/or Group VIB metal cations, such as a halogen, a nitrate, a sulfate, a silicate (orthosilicates and metasilicates), carbonates, hydroxides, and the like.
The third composition also may comprise an electropositive metal ion. As used herein, the term “electropositive metal ion” refers to metal ions that will be reduced by the metal substrate being treated when the pretreatment solution contacts the surface of the metallic substrate. As will be appreciated by one skilled in the art, the tendency of chemical species to be reduced is called the reduction potential, is expressed in volts, and is measured relative to the standard hydrogen electrode, which is arbitrarily assigned a reduction potential of zero. The reduction potential for several elements is set forth in Table 1 below (according to the CRC 82nd Edition, 2001-2002). An element or ion is more easily reduced than another element or ion if it has a voltage value, E*, in the following table, that is more positive than the elements or ions to which it is being compared.
Thus, as will be apparent, when the metal substrate comprises one of the materials listed earlier, such as cold rolled steel, hot rolled steel, steel coated with zinc metal, zinc compounds, or zinc alloys, hot-dipped galvanized steel, galvanealed steel, steel plated with zinc alloy, aluminum alloys, aluminum plated steel, aluminum alloy plated steel, suitable electropositive metal ions for deposition thereon include, for example, nickel, copper, silver, and gold, as well mixtures thereof.
The electropositive metal may comprise copper. When the electropositive metal ion comprises copper, both soluble and insoluble compounds may serve as a source of copper ions in the second pretreatment compositions. For example, the supplying source of copper ions in the pretreatment composition may be a water-soluble copper compound. Specific examples of such compounds include, but are not limited to, copper sulfate, copper nitrate, copper thiocyanate, disodium copper ethylenediaminetetraacetate tetrahydrate, copper bromide, copper oxide, copper hydroxide, copper chloride, copper fluoride, copper gluconate, copper citrate, copper lauroyl sarcosinate, copper lactate, copper oxalate, copper tartrate, copper malate, copper succinate, copper malonate, copper maleate, copper benzoate, copper salicylate, copper amino acid complexes, copper fumarate, copper glycerophosphate, sodium copper chlorophyllin, copper fluorosilicate, copper fluoroborate and copper iodate, as well as copper salts of carboxylic acids such as in the homologous series formic acid to decanoic acid, and copper salts of polybasic acids in the series oxalic acid to suberic acid.
When copper ions supplied from such a water-soluble copper compound are precipitated as an impurity in the form of copper sulfate, copper oxide, etc., it may be desirable to add a complexing agent that suppresses the precipitation of copper ions, thus stabilizing them as a copper complex in the composition.
The copper compound may be added as a copper complex salt such as or Cu-EDTA, which can be present stably in the second pretreatment composition on its own, but it is also possible to form a copper complex that can be present stably in the pretreatment composition by combining a complexing agent with a compound that is difficult to solubilize on its own. A n example thereof includes a Cu-EDTA complex formed by a combination of CuSO4 and EDTA·2Na.
The electropositive metal ion may be present in the third composition in an amount of at least 2 ppm based on the total weight of the third composition, such as at least 4 ppm, such as at least 6 ppm, such as at least 8 ppm, such as at least 10 ppm. The electropositive metal ion may be present in the third composition in an amount of no more than 100 ppm based on the total weight of the third composition, such as no more than 80 ppm, such as no more than 60 ppm, such as no more than 40 ppm, such as no more than 20 ppm. The electropositive metal ion may be present in the third composition in an amount of from 2 ppm to 100 ppm (calculated as metal ion), based on the total weight of the third composition, such as from 4 ppm to 80 ppm, such as from 6 ppm to 60 ppm, such as from 8 ppm to 40 ppm.
A source of free fluoride (as defined above) may be present in the third composition. Free fluoride in the third composition may be derived from Group IVB metals present in the third composition, including, for example, hexafluorozirconic acid or hexafluorotitanic acid. Additionally, other complex fluorides, such as H2SiF6 or HBF4, can be added to the third pretreatment composition to supply free fluoride. The skilled artisan will understand that the presence of free fluoride in the pretreatment bath can impact pretreatment deposition and etching of the substrate, hence it is critical to measure this bath parameter. The levels of free fluoride will depend on the pH and the addition of chelators into the third pretreatment bath and indicates the degree of fluoride association with the metal ions/protons present in the third pretreatment bath.
The free fluoride of the third composition may be present in an amount of at least 15 ppm based on a total weight of the third composition, such as at least 50 ppm. The free fluoride of the third pretreatment composition may be present in an amount of no more than 200 ppm based on a total weight of the third composition, such as no more than 100 ppm. The free fluoride of the third composition may be present in an amount of 15 ppm free fluoride to 200 ppm based on a total weight of the third composition, such as 50 ppm fluoride to 100 ppm.
The third composition optionally may comprise a Group VII metal such as iron, cobalt, nickel, or combinations thereof. Suitable sources of Group VII metals include iron (III) sulfate, iron (II) sulfate, iron (III) nitrate, iron (III) chloride, iron (III) oxide, iron (II) oxalate, cobalt (II) sulfate, cobalt (II) nitrate, cobalt (II) chloride, nickel (II) sulfate, nickel (II) nitrate, nickel (II) chloride, or combinations thereof.
The Group VII metal, if present at all, may be present in the third composition in an amount of at least 0.1 ppm based on total weight of the third composition, such as at least 1 ppm, and may be present in an amount of no more than 50 ppm based on total weight of the third composition, such as no more than 15 ppm. The Group VII metal, if present at all, may be present in the third composition in an amount of 0.1 ppm to 50 ppm based on total weight of the third composition, such as 1 ppm to 15 ppm.
The third composition may, in some instances, comprise an oxidizing agent. Non-limiting examples of the oxidizing agent include peroxides, persulfates, perchlorates, chlorates, hypochlorite, nitric acid, sparged oxygen, bromates, peroxi-benzoates, ozone, or combinations thereof.
The oxidizing agent may be present, if at all, in an amount of at least 50 ppm based on total weight of the third composition, such as at least 500 ppm, and in some instances, may be present in an amount of no more than 13,000 ppm based on total weight of the third composition, such as no more than 3,000 ppm. In some instances, the oxidizing agent may be present in the third composition, if at all, in an amount of 100 ppm to 13,000 ppm based on total weight of the third pretreatment composition, such as 500 ppm to 3,000 ppm. As used herein, the term “oxidizing agent,” when used with respect to a component of the third pretreatment composition, refers to a chemical which is capable of oxidizing at least one of: a metal present in the substrate which is contacted by the third pretreatment composition and/or a metal-complexing agent present in the third pretreatment composition. As used herein with respect to “oxidizing agent,” the phrase “capable of oxidizing” means capable of removing electrons from an atom or a molecule present in the substrate or the third pretreatment composition, as the case may be, thereby decreasing the number of electrons of such atom or molecule.
As discussed above with respect to the first composition, the third composition may exclude chromium or chromium-containing compounds. That is, the third composition and/or coatings or layers deposited from the third composition may be substantially free, may be essentially free, and/or may be completely free of such chromium or chromium-containing compounds.
As discussed above with respect to the first composition, the third composition may, in some instances, exclude phosphate ions or phosphate-containing compounds and/or the formation of sludge. That is, the third composition and/or coatings or layers deposited from the third composition may be substantially free, or essentially free, or completely free, of phosphate ions or phosphate-containing compounds.
Optionally, the third composition may further comprise a source of phosphate ions. For clarity, when used herein, “phosphate ions” refers to phosphate ions that derive from or originate from inorganic phosphate compounds. For example, in some instances, phosphate ions may be present in an amount of greater than 5 ppm, based on total weight of the pretreatment composition, such as 10 ppm, such as 20 ppm. In some instances, phosphate ions may be present in an amount of no more than 60 ppm, based on total weight of the second pretreatment composition, such as no more than 40 ppm, such as no more than 30 ppm. In some instances, phosphate ions may be present in an amount of from 5 ppm to 60 ppm, based on total weight of the pretreatment composition, such as from 10 ppm to 40 ppm, such as from 20 ppm to 30 ppm.
The pH of the third composition may be 6.5 or less, such as 5.5 or less, such as 4.5 or less, such as 3.5 or less. The pH of the third composition may, in some instances, be 2.0 to 6.5, such as 3 to 4.5, and may be adjusted using, for example, any acid and/or base as is necessary. The pH of the third composition may be maintained through the inclusion of an acidic material, including water soluble and/or water dispersible acids, such as nitric acid, sulfuric acid, and/or phosphoric acid. The pH of the third composition may be maintained through the inclusion of a basic material, including water soluble and/or water dispersible bases, such as sodium hydroxide, sodium carbonate, potassium hydroxide, ammonium hydroxide, ammonia, and/or amines such as triethylamine, methylethyl amine, or mixtures thereof.
The third composition may comprise a carrier, often an aqueous medium, so that the composition is in the form of a solution or dispersion of the Group IVB metal in the carrier. For example, the third composition may be an aqueous composition. The solution or dispersion may be brought into contact with the substrate by any of a variety of known techniques, such as dipping or immersion, spraying, intermittent spraying, dipping followed by spraying, spraying followed by dipping, brushing, or roll-coating. The solution or dispersion when applied to the metal substrate is at a temperature of 20° C. to 50° C., such as 25° C. to 40° C. For example, the pretreatment process may be carried out at ambient or room temperature. The contact time is often from 5 seconds to 15 minutes, such as 10 seconds to 10 minutes, such as 15 seconds to 3 minutes.
Following the contacting with one of the second compositions disclosed herein, the substrate optionally may be air dried at room temperature or may be dried with hot air as described above with respect to the first composition.
Following the contacting with one of the second compositions disclosed herein, the substrate optionally may be rinsed with tap water, deionized water, and/or an aqueous solution of rinsing agents in order to remove any residue and then optionally may be dried, for example air dried or dried with hot air as described above with respect to the first composition.
The first, second, and/or third composition may further comprise a foam depressor, including by way of non-limiting example Foam Depressor 304 CK (commercially available from PPG Industries, Inc.). Those skilled in the art of pretreatment technologies understand that foam in a pretreatment bath may have a negative impact on substrate wetting and the appearance or quality of a film formed by a pretreatment composition. Accordingly, foam depressors may be added to a composition to prevent the formation of foam or to break foam already present, particularly in spray applications. Defoaming surfactants may optionally be present at levels up to 1 weight percent, such as up to 0.1 percent by weight, and wetting agents are typically present at levels up to 2 percent, such as up to 0.5 percent by weight, based on the total weight of the composition.
The first, second, and/or third composition may optionally contain other materials in addition to those described above, such as nonionic surfactants and auxiliaries conventionally used in the art of substrate protection. In an aqueous medium, water dispersible organic solvents, for example, alcohols with up to about 8 carbon atoms, such as methanol, isopropanol, 1-methoxy-2-propanol, and the like, may be present; or glycol ethers such as the monoalkyl ethers of ethylene glycol, diethylene glycol, or propylene glycol, and the like; dimethylformamide; xylene; a base such as an amine which can partially or completely neutralize the organophosphate or organophosphonate compound to enhance the solubility of the organophosphate or organophosphonate compounds, such as diisopropanolamine, triethylamine, dimethylethanolamine, and 2-amino-2-methylpropanol; and combinations thereof. When present, water dispersible organic solvents are typically used in amounts up to about ten percent by volume, based on the total volume of the pretreatment, as the case may be. Other optional materials include surfactants that function as defoamers or substrate wetting agents. Anionic, cationic, amphoteric, and/or nonionic surfactants may be used.
The first, second, and/or third composition optionally may comprise a reaction accelerator, such as nitrite ions, nitrate ions, nitro-group containing compounds, hydroxylamine sulfate, persulfate ions, sulfite ions, hyposulfite ions, peroxides (except in the case of the first composition), iron (III) ions, citric acid iron compounds, bromate ions, perchlorinate ions, chlorate ions, chlorite ions as well as ascorbic acid, citric acid, tartaric acid, malonic acid, succinic acid and salts thereof.
The system of the present invention optionally may further comprise a cleaner. At least a portion of the substrate surface may be cleaned prior to contacting at least a portion of the substrate surface with one of the compositions described above in order to remove grease, dirt, and/or other extraneous matter. At least a portion of the surface of the substrate may be cleaned by physical and/or chemical means, such as mechanically abrading the surface and/or cleaning/degreasing the surface with commercially available alkaline or acidic cleaning agents that are well known to those skilled in the art. Examples of alkaline cleaners suitable for include Chemkleen™ 166HP, 166M/C, 177, 181ALP, 490MX, 2010LP, and Surface Prep 1 (SP1), Ultrax 32, Ultrax 97, Ultrax 29, and Ultrax92D, each of which are commercially available from PPG Industries, Inc. (Cleveland, OH), and any of the DFM Series, RECC 1001, and 88X1002 cleaners (commercially available from PRC-DeSoto International, Sylmar, CA), and Turco 4215-NCLT and Ridolene (commercially available from Henkel Technologies, Madison Heights, MI). Examples of acidic cleaners suitable for use include Acid Metal Cleaner (AMC) 23, AMC 239, AMC 240, and AMC 533, AMC66AW, and acetic acid. Such cleaners are often preceded and/or followed by a water rinse, such as with tap water, distilled water, or combinations thereof.
Following the cleaning step(s), the substrate optionally may be rinsed with tap water, deionized water, and/or an aqueous solution of rinsing agents in order to remove any residue. The wet substrate surface may be treated with one of the pretreatment compositions described above or the substrate may be dried prior to treating the substrate surface, such as air dried, for example, by using an air knife, by flashing off the water by brief exposure of the substrate to a high temperature, such as 15° C. to 100° C., such as 20° C. to 90° C., or in a heater assembly using, for example, infrared heat, such as for 10 minutes at 70° C., or by passing the substrate between squeegee rolls.
The systems of the present invention may further comprise a coating composition. The coating composition may comprise, or consist essentially of, or consist of, a film-forming resin. Any suitable technique may be used to deposit such a coating composition onto the substrate, including, for example, brushing, dipping, flow coating, spraying and the like. Optionally, however, as described in more detail below, such depositing of a coating composition may comprise an electrocoating step wherein an electrodepositable coating composition is deposited onto a metal substrate by electrodeposition. In certain other instances, as described in more detail below, such depositing of a coating composition comprises a powder coating step. In still other instances, the coating composition may be a liquid coating composition.
The coating composition may comprise a thermosetting film-forming resin or a thermoplastic film-forming resin. As used herein, the term “film-forming resin” refers to resins that can form a self-supporting continuous film on at least a horizontal surface of a substrate upon removal of any diluents or carriers present in the composition and/or upon curing at ambient or elevated temperature. Conventional film-forming resins that may be used include, without limitation, those typically used in automotive OEM coating compositions, automotive refinish coating compositions, industrial coating compositions, architectural coating compositions, coil coating compositions, and aerospace coating compositions, among others. As used herein, the term “thermosetting” refers to resins that “set” irreversibly upon curing or crosslinking, wherein the polymer chains of the polymeric components are joined together by covalent bonds. This property is usually associated with a cross-linking reaction of the composition constituents often induced, for example, by heat or radiation. Curing or crosslinking reactions also may be carried out under ambient conditions. Once cured or crosslinked, a thermosetting resin will not melt upon the application of heat and is insoluble in solvents. As used herein, the term “thermoplastic” refers to resins that comprise polymeric components that are not joined by covalent bonds and thereby can undergo liquid flow upon heating and are soluble in solvents.
As previously indicated, the coating composition may be an electrodepositable coating composition comprising a water-dispersible, ionic salt group-containing film-forming resin that may be deposited onto the substrate by an electrocoating step wherein the electrodepositable coating composition is deposited onto the metal substrate under the influence of an applied electrical potential, i.e., by electrodeposition. The ionic salt group-containing film-forming polymer may comprise a cationic salt group containing film-forming polymer for use in a cationic electrodepositable coating composition. As used herein, the term “cationic salt group-containing film-forming polymer” refers to polymers that include at least partially neutralized cationic groups, such as sulfonium groups and ammonium groups, that impart a positive charge. The cationic salt group-containing film-forming polymer may comprise active hydrogen functional groups, including, for example, hydroxyl groups, primary or secondary amino groups, and thiol groups. Cationic salt group-containing film-forming polymers that comprise active hydrogen functional groups may be referred to as active hydrogen-containing, cationic salt group-containing film-forming polymers. Examples of polymers that are suitable for use as the cationic salt group-containing film-forming polymer include, but are not limited to, alkyd polymers, acrylics, polyepoxides, polyamides, polyurethanes, polyureas, polyethers, and polyesters, among others. The cationic salt group-containing film-forming polymer may be present in the cationic electrodepositable coating composition in an amount of 40% to 90% by weight, such as 50% to 80% by weight, such as 60% to 75% by weight based on the total weight of the resin solids of the electrodepositable coating composition. As used herein, the “resin solids” include the ionic salt group-containing film-forming polymer, curing agent (as discussed below), and any additional water-dispersible non-pigmented component(s) present in the electrodepositable coating composition.
Alternatively, the ionic salt group containing film-forming polymer may comprise an anionic salt group containing film-forming polymer for use in an anionic electrodepositable coating composition. As used herein, the term “anionic salt group containing film-forming polymer” refers to an anionic polymer comprising at least partially neutralized anionic functional groups, such as carboxylic acid and phosphoric acid groups that impart a negative charge. The anionic salt group-containing film-forming polymer may comprise active hydrogen functional groups. Anionic salt group-containing film-forming polymers that comprise active hydrogen functional groups may be referred to as active hydrogen-containing, anionic salt group-containing film-forming polymers. The anionic salt group-containing film-forming polymer may comprise base-solubilized, carboxylic acid group-containing film-forming polymers such as the reaction product or adduct of a drying oil or semi-drying fatty acid ester with a dicarboxylic acid or anhydride; and the reaction product of a fatty acid ester, unsaturated acid or anhydride and any additional unsaturated modifying materials which are further reacted with polyol. Also suitable are the at least partially neutralized interpolymers of hydroxy-alkyl esters of unsaturated carboxylic acids, unsaturated carboxylic acid and at least one other ethylenically unsaturated monomer. Still another suitable anionic electrodepositable resin comprises an alkyd-aminoplast vehicle, i.e., a vehicle containing an alkyd resin and an amine-aldehyde resin. Another suitable anionic electrodepositable resin composition comprises mixed esters of a resinous polyol. Other acid functional polymers may also be used such as phosphatized polyepoxide or phosphatized acrylic polymers. Exemplary phosphatized polyepoxides are disclosed in U.S. Patent Application Publication No. 2009-0045071 at [0004]-[0015] and U.S. patent application Ser. No. 13/232,093 at [0014]-[0040], the cited portions of which being incorporated herein by reference. The anionic salt group-containing film-forming polymer may be present in the anionic electrodepositable coating composition in an amount 50% to 90%, such as 55% to 80%, such as 60% to 75% based on the total weight of the resin solids of the electrodepositable coating composition.
The electrodepositable coating composition may further comprise a curing agent. The curing agent may comprise functional groups that are reactive with the functional groups, such as active hydrogen groups, of the ionic salt group-containing film-forming polymer to effectuate cure of the coating composition to form a coating. Non-limiting examples of suitable curing agents are at least partially blocked polyisocyanates, aminoplast resins and phenoplast resins, such as phenolformaldehyde condensates including allyl ether derivatives thereof. The curing agent may be present in the cationic electrodepositable coating composition in an amount of 10% to 60% by weight, such as 20% to 50% by weight, such as 25% to 40% by weight based on the total weight of the resin solids of the electrodepositable coating composition. Alternatively, the curing agent may be present in the anionic electrodepositable coating composition in an amount of 10% to 50% by weight, such as 20% to 45% by weight, such as 25% to 40% by weight based on the total weight of the resin solids of the electrodepositable coating composition.
The electrodepositable coating composition may further comprise other optional ingredients, such as a pigment composition and, if desired, various additives such as fillers, plasticizers, antioxidants, biocides, UV light absorbers and stabilizers, hindered amine light stabilizers, defoamers, fungicides, dispersing aids, flow control agents, surfactants, wetting agents, or combinations thereof.
The electrodepositable coating composition may comprise water and/or one or more organic solvent(s). Water can for example be present in amounts of 40% to 90% by weight, such as 50% to 75% by weight based on total weight of the electrodepositable coating composition. If used, the organic solvents may typically be present in an amount of less than 10% by weight, such as less than 5% by weight based on total weight of the electrodepositable coating composition. The electrodepositable coating composition may in particular be provided in the form of an aqueous dispersion. The total solids content of the electrodepositable coating composition may be from 1% to 50% by weight, such as 5% to 40% by weight, such as 5% to 20% by weight based on the total weight of the electrodepositable coating composition. As used herein, “total solids” refers to the non-volatile content of the electrodepositable coating composition, i.e., materials which will not volatilize when heated to 110° C. for 15 minutes.
The cationic electrodepositable coating composition may be deposited upon an electrically conductive substrate by placing the composition in contact with an electrically conductive cathode and an electrically conductive anode, with the surface to be coated being the cathode. Alternatively, the anionic electrodepositable coating composition may be deposited upon an electrically conductive substrate by placing the composition in contact with an electrically conductive cathode and an electrically conductive anode, with the surface to be coated being the anode. An adherent film of the electrodepositable coating composition is deposited in a substantially continuous manner on the cathode or anode, respectively, when a sufficient voltage is impressed between the electrodes. The applied voltage may be varied and can be, for example, as low as one volt to as high as several thousand volts, such as between 50 and 500 volts. Current density is usually between 1.0 ampere and 15 amperes per square foot (10.8 to 161.5 amperes per square meter) and tends to decrease quickly during the electrodeposition process, indicating formation of a continuous self-insulating film.
Once the cationic or anionic electrodepositable coating composition is electrodeposited over at least a portion of the electroconductive substrate, the coated substrate may be heated to a temperature and for a time sufficient to cure the electrodeposited coating on the substrate. For cationic electrodeposition, the coated substrate may be heated to a temperature ranging from 230° F. to 450° F. (110° C. to 232.2° C.), such as from 275° F. to 400° F. (135° C. to 204.4° C.), such as from 300° F. to 360° F. (149° C. to 180° C.). For anionic electrodeposition, the coated substrate may be heated to a temperature ranging from 200° F. to 450° F. (93° C. to 232.2° C.), such as from 275° F. to 400° F. (135° C. to 204.4° C.), such as from 300° F. to 360° F. (149° C. to 180° C.), such as 200° F. to 210.2° F. (93° C. to 99° C.). The curing time may be dependent upon the curing temperature as well as other variables, for example, the film thickness of the electrodeposited coating, level and type of catalyst present in the composition and the like. For example, the curing time can range from 10 minutes to 60 minutes, such as 20 to 40 minutes. The thickness of the resultant cured electrodeposited coating may range from 10 to 50 microns.
Alternatively, as mentioned above, after the substrate has been contacted with the pretreatment compositions as described above, a powder coating composition may then be deposited onto at least a portion of the pretreated substrate surface. As used herein, “powder coating composition” refers to a coating composition in the form of a co-reactable solid in particulate form which is substantially or completely free of water and/or solvent. Accordingly, the powder coating composition disclosed herein is not synonymous to waterborne and/or solvent-borne coating compositions known in the art. The powder coating composition may comprise (a) a film forming polymer having a reactive functional group; and (b) a curing agent having a functional group that is reactive with the functional group of the film-forming polymer. Examples of powder coating compositions that may be used in the present invention include the polyester-based ENVIROCRON line of powder coating compositions (commercially available from PPG Industries, Inc.) or epoxy-polyester hybrid powder coating compositions. Alternative examples of powder coating compositions that may be used include low temperature cure thermosetting powder coating compositions comprising (a) at least one tertiary aminourea compound, at least one tertiary aminourethane compound, or mixtures thereof, and (b) at least one film-forming epoxy-containing resin and/or at least one siloxane-containing resin (such as those described in U.S. Pat. No. 7,470,752, assigned to PPG Industries, Inc. and incorporated herein by reference); curable powder coating compositions generally comprising (a) at least one tertiary aminourea compound, at least one tertiary aminourethane compound, or mixtures thereof, and (b) at least one film-forming epoxy-containing resin and/or at least one siloxane-containing resin (such as those described in U.S. Pat. No. 7,432,333, assigned to PPG Industries, Inc. and incorporated herein by reference); and those comprising a solid particulate mixture of a reactive group-containing polymer having a Tg of at least 30° C. (such as those described in U.S. Pat. No. 6,797,387, assigned to PPG Industries, Inc. and incorporated herein by reference). The powder coating compositions are often applied by spraying, electrostatic spraying, or by the use of a fluidized bed. Other standard methods for coating application of the powder coating also can be employed such as brushing, dipping or flowing. After application of the powder coating composition, the coating is often heated to cure the deposited composition. The heating or curing operation is often carried out at a temperature in the range of from 130° C. to 220° C., such as from 170° C. to 190° C., for a period of time ranging from 10 minutes to 30 minutes, such 15 minutes to 25 minutes. The thickness of the resultant film is from 50 microns to 125 microns.
As mentioned above, after the substrate has been contacted with the pretreatment compositions as described above, a liquid coating composition may then be applied or deposited onto at least a portion of the substrate surface. As used herein, “liquid coating composition” refers to a coating composition which contains a portion of water and/or solvent that may be substantially or completely removed from the composition upon drying and/or curing. Accordingly, the liquid coating composition disclosed herein is synonymous to waterborne and/or solvent-borne coating compositions known in the art.
The liquid coating composition may comprise, for example, (a) a film forming polymer having a reactive functional group; and (b) a curing agent having a functional group that is reactive with the functional group of the film-forming polymer. In other examples, the liquid coating may contain a film forming polymer that may react with oxygen in the air or coalesce into a film with the evaporation of water and/or solvents. These film-forming mechanisms may require or be accelerated by the application of heat or some type of radiation such as Ultraviolet or Infrared. Examples of liquid coating compositions that may be used include the SPECTRACRON® line of solvent-based coating compositions, the AQUACRON® line of water-based coating compositions, and the RAYCRON® line of UV cured coatings (all commercially available from PPG Industries, Inc.). Suitable film forming polymers that may be used in the liquid coating composition may comprise a (poly)ester, an alkyd, a (poly)urethane, an isocyanurate, a (poly)urea, a (poly)epoxy, an anhydride, an acrylic, a (poly)ether, a (poly)sulfide, a (poly)amine, a (poly)amide, (poly)vinyl chloride, (poly)olefin, (poly)vinylidene fluoride, (poly)siloxane, or combinations thereof.
The film-forming resin may, in examples, be a primer composition and/or a topcoat composition. The primer and/or topcoat compositions may be, for examples, chromate-based primers and/or advanced performance topcoats. The primer coat can be a conventional chromate-based primer coat, such as those available from PPG Industries, Inc. (product code 44GN072), or a chrome-free primer such as those available from PPG (DESOPRIME CA7502, DESOPRIME CA7521, Deft 02GN083, Deft 02GN084). Alternately, the primer coat can be a chromate-free primer coat, such as the coating compositions described in U.S. patent application Ser. No. 10/758,973, titled “CORROSION RESISTANT COATINGS CONTAINING CARBON”, and U.S. patent application Ser. Nos. 10/758,972, and 10/758,972, both titled “CORROSION RESISTANT COATINGS”, all of which are incorporated herein by reference, and other chrome-free primers that are known in the art, and which can pass the military requirement of MIL-PRF-85582 Class N or MIL-PRF-23377 Class N may also be used with the current invention.
As mentioned above, the substrate of the present invention also may comprise a topcoat. As used herein, the term “topcoat” refers to a mixture of binder(s) which can be an organic or inorganic based polymer or a blend of polymers, typically at least one pigment, can optionally contain at least one solvent or mixture of solvents, and can optionally contain at least one curing agent. A topcoat is typically the coating layer in a single or multi-layer coating system whose outer surface is exposed to the atmosphere or environment, and its inner surface is in contact with another coating layer or polymeric substrate. Examples of suitable topcoats include those conforming to MIL-PRF-85285D, such as those available from PPG (Deft 03W127A and Deft 03GY292). The topcoat may be an advanced performance topcoat, such as those available from PPG (Defthane® ELT™ 99GY001 and 99W009). However, other topcoats and advanced performance topcoats can be used as will be understood by those of skill in the art with reference to this disclosure.
The metal substrate also may comprise a self-priming topcoat, or an enhanced self-priming topcoat. The term “self-priming topcoat”, also referred to as a “direct to substrate” or “direct to metal” coating, refers to a mixture of a binder(s), which can be an organic or inorganic based polymer or blend of polymers, typically at least one pigment, can optionally contain at least one solvent or mixture of solvents, and can optionally contain at least one curing agent. The term “enhanced self-priming topcoat”, also referred to as an “enhanced direct to substrate coating” refers to a mixture of functionalized fluorinated binders, such as a fluoroethylene-alkyl vinyl ether in whole or in part with other binder(s), which can be an organic or inorganic based polymer or blend of polymers, typically at least one pigment, can optionally contain at least one solvent or mixture of solvents, and can optionally contain at least one curing agent. Examples of self-priming topcoats include those that conform to TT-P-2756A. Examples of self-priming topcoats include those available from PPG (03W169 and 03GY369), and examples of enhanced self-priming topcoats include Defthane® ELT™/ESPT and product code number 97GY121, available from PPG. However, other self-priming topcoats and enhanced self-priming topcoats can be used in the coating system as will be understood by those of skill in the art with reference to this disclosure.
The self-priming topcoat and enhanced self-priming topcoat may be applied directly to the pretreated substrate. The self-priming topcoat and enhanced self-priming topcoat can optionally be applied to an organic or inorganic polymeric coating, such as a primer or paint film. The self-priming topcoat layer and enhanced self-priming topcoat is typically the coating layer in a single or multi-layer coating system where the outer surface of the coating is exposed to the atmosphere or environment, and the inner surface of the coating is typically in contact with the substrate or optional polymer coating or primer.
The topcoat, self-priming topcoat, and enhanced self-priming topcoat can be applied to the pretreated substrate, in either a wet or “not fully cured” condition that dries or cures over time, that is, solvent evaporates and/or there is a chemical reaction. The coatings can dry or cure either naturally or by accelerated means for example, an ultraviolet light cured system to form a film or “cured” paint.
In addition, a colorant and, if desired, various additives such as surfactants, wetting agents or catalyst can be included in the coating composition (electrodepositable, powder, or liquid). As used herein, the term “colorant” means any substance that imparts color and/or other opacity and/or other visual effect to the composition. Example colorants include pigments, dyes and tints, such as those used in the paint industry and/or listed in the Dry Color Manufacturers Association (DCMA), as well as special effect compositions. In general, the colorant can be present in the coating composition in any amount sufficient to impart the desired visual and/or color effect. The colorant may comprise from 1 to 65 weight percent, such as from 3 to 40 weight percent or 5 to 35 weight percent, with weight percent based on the total weight of the composition.
The present invention also is directed to systems for treating a metal substrate. In examples, the system may comprise, or may consist essentially of, or may consist of, one of the first compositions disclosed herein. In examples, the system may comprise, or consist essentially of, or consist of one of the first compositions disclosed herein; and one of the second compositions disclosed herein; and/or one of the third compositions disclosed herein. For example, the system may comprise, or may consist essentially of, or may consist of, one of the first compositions disclosed herein and one of the second compositions disclosed herein. The system may comprise, or may consist essentially of, or may consist of one of the first pretreatment compositions disclosed herein and one of the third compositions disclosed herein. For example, the first composition may comprise, or consist essentially of, or consist of, a first lanthanide series metal and having a pH of less than 2.0 and being substantially free, or essentially free, or completely free of peroxide. For example, the second composition may comprise, or consist essentially of, or consist of, a fluorometallic acid comprising a Group IVA metal and having a pH of 1.0 to 4.0. For example, the third pretreatment composition may comprise, or consist essentially of, or consist of, a Group IVB metal. The system also may further comprise one of the cleaner compositions and/or film-forming resins described above.
The present invention also is directed to methods for treating a metal substrate. In examples, the method of treating may comprise, or may consist essentially of, or may consist of, contacting at least a portion of a substrate surface with one of the first compositions disclosed herein. In examples, the method may comprise, or consist essentially of, or consist of: contacting at least a portion of a substrate surface with one of the first compositions disclosed herein; and contacting at least a portion of the surface with one of the second compositions disclosed herein; or contacting at least a portion of the surface with one of the third compositions disclosed herein. For example, the first composition may comprise, or consist essentially of, or consist of, a first lanthanide series metal and having a pH of less than 2.0 and being substantially free, or essentially free, or completely free of peroxide. For example, the second composition may comprise, or consist essentially of, or consist of, a fluorometallic acid comprising a Group IVA metal and having a pH of 1.0 to 4.0. For example, the third pretreatment composition may comprise, or consist essentially of, or consist of, a Group IVB metal. The method also may further comprise contacting at least a portion of the substrate surface with one of the cleaner compositions, film-forming resins, and/or water or rinse agents described above.
The present invention also is directed to substrates treated with one of the systems and/or methods disclosed herein. In examples, a substrate treated with the systems or methods of the present invention may have a scribe creep on a substrate surface that is at least maintained compared to a substrate contacted with a composition comprising lanthanide series metal and an oxidizing agent, wherein the scribe creep is measured following ASTM G85 A2 testing for at least 1 week, GMW14872 corrosion testing for at least forty days, and/or CASS testing for at least 1 week. As used herein, the phrase “at least maintained” means that, following corrosion testing (i.e., ASTM G85 A2 testing for at least 1 week, GMW14872 corrosion testing for at least forty days, and/or CASS testing for at least 1 week), the scribe creep on a substrate surface treated with a composition, system and/or method of the present invention was equal to or less than the scribe creep that occurred on a substrate surface that was contacted with a composition comprising a lanthanide series metal and an oxidizing agent prior to exposure to such corrosion testing.
Illustrating the invention are the following examples, which, however, are not to be considered as limiting the invention to their details. Unless otherwise indicated, all parts and percentages in the following examples, as well as throughout the specification, are by weight.
In order to remove the surface oil from the metal substrates, an alkaline solution including Chemkleen 2010LP (a phosphate-free alkaline cleaner available from PPG Industries, Inc.) and Chemkleen 181ALP (a phosphate-free blended surfactant additive available from PPG Industries, Inc.) or CKSP1 (an alkaline cleaner available from PPG Industries, Inc.) and CK185A (a blended surfactant additive available from PPG Industries, Inc.) was prepared. For a 10-gallon composition, 500 mL of Chemkleen 2010LP and 50 mL of Chemkleen 181ALP or 500 mL of CKSP1 and 50 mL of CK185A were added in deionized water and the solution temperature was raised to 120° F.
The native oxide layer of the metal substrate was removed by cleaning the substrate surface with one of the acid cleaners described below. Potassium bifluoride (99.3 wt. %) was purchased from Sigma-Aldrich (St. Louis, MO), hydrofluorosilicic acid (23 wt. %), and sodium hydroxide were purchased from Thermofisher Acros Organics (Geel, Belgium). Fluorozirconic acid (45 wt. % in water) was purchased from Honeywell International, Inc. (Morristown, NJ). Concentrated sulfuric acid was purchased from Fisher Chemical (Pittsburgh, PA) and copper nitrate solution (18 wt. % Cu in water) was purchased from Shepherd Chemical Company (Cincinnati, OH). Wherever applicable, the pH of the deoxidizer composition was measured using a pH meter (DualStar pH/ISE Dual Channel Benchtop Meter, available from ThermoFisher Scientific, Waltham, Massachusetts, USA); pH probe, Fisher Scientific Accumet pH probe (Ag/AgCl reference electrode) by immersing the pH probe in the deoxidizer composition. Free fluoride was measured using a DualStar pH/ISE Dual Channel Benchtop Meter (ThermoFisher Scientific) equipped with a fluoride selective electrode (Orion ISE Fluoride Electrode, solid state, available from ThermoFisher Scientific) by immersing the ISE in the deoxidizer solution and allowing the measurement to equilibrate.
In a clean 3-gallon plastic bucket, 11.34 liters of deionized water were added. Subsequently, sulfuric acid (48 g) and fluorozirconic acid (4.8 g) were added in the bath. The prepared solution was heated to 90° F. and maintained under high stirring using an immersion heater (Polyscience Sous Vide Professional, Model #7306AC1B5, available from Polyscience, Niles, Illinois).
In a clean 3-gallon plastic bucket, 11.34 liters of deionized water were added. Subsequently, hydrofluorosilicic acid (109.16 g), potassium bifluoride (6.97 g), and sodium hydroxide (9.48 g) were added in the bath. The prepared solution was heated to 80° F. and maintained under high stirring using the immersion heater described above.
In a clean 3-gallon plastic bucket, 11.34 liters of deionized water were added. Subsequently, hydrofluorosilicic acid (109.16 g), potassium bifluoride (6.97 g), and sodium hydroxide (9.48 g) were added in the bath. A copper nitrate solution was prepared by dilution of a stock copper nitrate solution (18 wt. % Cu in water) and was added in the bath (21 g, 2 wt %). The prepared solution was heated to 80° F. and maintained under high stirring using the immersion heater described above.
Five compositions containing cerium salts and different additives were prepared and their performance in regard to corrosion properties was compared against CeCl3·7H2O+H2O2 or Zircobond® pretreatment composition (a zirconium-containing pretreatment composition commercially available from PPG Industries, Inc.). Ammonium cerium nitrate and CeCl3·7H2O were supplied by Acros Organics (Geel, Belgium). Gadolinium nitrate was purchased from Alfa Aesar (Ward Hill, MA). Sodium phosphotungstate was purchased from Sigma-Aldrich (St. Louis, MO). Nupal 435 is commercially available from PPG Industries, Inc.
All of the compositions, as detailed below, were prepared in deionized water and maintained at room temperature. The pH of the compositions was measured using a pH meter (DualStar pH/ISE Dual Channel Benchtop Meter, available from ThermoFisher Scientific, Waltham, Massachusetts, USA; pH probe, Fisher Scientific Accumet pH probe (Ag/AgCl reference electrode) by immersing the pH probe in the composition. When panels were immersed in the composition, the composition was kept under magnetic stirring or the substrate holder rack was manually agitated to keep the uniform distribution of reactive species throughout the solution.
To a clean one-gallon plastic container was added 3.0 liters of deionized water. Ammonium cerium nitrate (8.29 g) was then added. The composition was manually stirred using a glass rod and the volume was filled to 3.78 liters with the addition of deionized water. The pH of the composition was measured using the pH meter as described above.
To a clean one-gallon plastic container was added 3.0 liters of deionized water. Ammonium cerium nitrate (8.29 g) and gadolinium nitrate (2.6 g) were then added. The composition was manually stirred using a glass rod and the volume was filled to 3.78 liters with the addition of deionized water. The pH of the composition was measured using the pH meter as described above.
(iii) Composition 3 (PT-3, Corresponds to First Composition)
To a clean one-gallon plastic container was added 3.0 liters of deionized water. Ammonium cerium nitrate (8.29 g) and sodium phosphotungstate (2.23 g) were then added. The composition was manually stirred using a glass rod and the volume was filled to 3.78 liters with the addition of deionized water. The pH of the composition was measured using the pH meter as described above.
(iii) Composition 4 (PT-4, Corresponds to First Composition)
To a clean one-gallon plastic container was added 3.0 liters of deionized water. Ammonium cerium nitrate (8.29 g) and copper nitrate (2wt %, 7 g) were then added. The composition was manually stirred using a glass rod and the volume was filled to 3.78 liters with the addition of deionized water. The pH of the composition was measured using the pH meter as described above.
To a clean one-gallon plastic container was added 3.0 liters of deionized water. Ammonium cerium nitrate (8.29 g) and NUPAL 435 (378 g) were then added. The composition was manually stirred using a glass rod and the volume was filled to 3.78 liters with the addition of deionized water. The pH of the composition was measured using the pH meter as described above.
(vii) Composition 6 (PT-6, Control)
To a clean one-gallon plastic container was added 3.0 liters of deionized water. Cerium chloride (5.67 g) and hydrogen peroxide (9.45 g) were then added. The composition was manually stirred using a glass rod to dissolve the added salts and the volume was filled to 3.78 liters with the addition of deionized water. The pH of the composition was measured using the pH meter as described above.
(viii) Composition (PT-7, Corresponds to Third Composition)
One gallon of Zircobond® 1.5, a zirconium-containing pretreatment composition (commercially available from PPG Industries, Inc.) was prepared according to manufacturer's instructions. The composition was manually stirred using a glass rod.
Cold rolled steel (CRS) and aluminum alloy AA6111 and AA6022 substrates were purchased from ACT Test Panels, LLC (Hillsdale, MI). Aluminum and CRS substrates were cut from 4″ by 12″ to 4″ by 6″ using a panel cutter prior to application of the alkaline cleaner.
Panels treated in Examples 1-2 were treated according to Process A. Panels were spray cleaned and degreased for 120 seconds at 10-15 psi in one of the alkaline cleaners described above (120° F.) using Vee-jet nozzles and rinsed with deionized water by immersing in a deionized water bath (75° F.) for 30 seconds followed by a deionized water spray rinse using a Melnor Rear-Trigger 7-Pattern nozzle set to shower mode (available from Home Depot). Cleaned substrates were immersed in one of the PT-1 to PT-6 baths for 120 seconds at room temperature. During the immersion, a low agitation was maintained in the solution via manually shaking the panel holders. Pretreated substrates were rinsed by a deionized water spray using a Melnor Rear-Trigger 7-Pattern nozzle set to shower mode (75° F.) for 30 seconds and dried with hot air for approximately 120 seconds using a Hi-Velocity handheld blow-dryer made by Oster® (model number 078302-300-000) on high-setting.
Panels treated in Examples 3-7 were treated according to Process B. Panels were degreased and water cleaned through immersion and spraying steps as described above. After the chemical cleaning, panels were immersed in one of the Deoxidizer Compositions (DX-1 to DX-3) described above at 80-90° F. for 120 seconds under high agitation and then were rinsed by a DI water spray rinse using a Melnor Rear-Trigger 7-Pattern nozzle set to shower mode for 30 seconds. Then, panels were immersed in one of the compositions PT-1 to PT-4 or PT-6 baths for 120 seconds at room temperature. During the immersion, a low agitation was maintained in the solution via manually shaking the panel holders. Treated substrates were rinsed by a deionized water spray using a Melnor Rear-Trigger 7-Pattern nozzle set to shower mode (75° F.) for 30 seconds and dried with hot air for approximately 120 seconds using a Hi-Velocity handheld blow-dryer made by Oster® (model number 078302-300-000) on high-setting.
Panels treated in Example 8 were treated according to Process C. Panels were degreased and water cleaned through immersion and spraying steps as described above. After the chemical cleaning, panels were immersed in PT-7 bath for 120 seconds at room temperature. During the immersion, a low agitation was maintained in the solution. Treated substrates were rinsed by a deionized water spray using a Melnor Rear-Trigger 7-Pattern nozzle set to shower mode (75° F.) for 30 seconds. After this, treated panels were immersed in PT-1 bath for 120 seconds at room temperature. During the immersion, a low agitation was maintained in the solution via manually shaking the panel holders. Pretreated substrates were rinsed by a deionized water spray using a Melnor Rear-Trigger 7-Pattern nozzle set to shower mode (75° F.) for 30 seconds and dried with hot air for approximately 120 seconds using a Hi-Velocity handheld blow-dryer made by Oster® (model number 078302-300-000) on high-setting.
After the AA6111, AA6022, and CRS panels were treated according to one of Processes A to C, some of the panels were electrocoated with EPIC 200 FRAP (a cationic electrocoat with components commercially available from PPG Industries, Inc.) as detailed below. After the mixing of all the necessary components to prepare the electrocoat bath (resin, paste, and deionized water), ultrafitration was performed where ˜25% of the electrocoat bath was removed, which was replenished with fresh deionized water. During the electrocoating step, panels were held ˜200 V at 90° F. with a ramp time of 30 seconds, targeting the final thickness of electrocoat ˜0.65+0.1 mils. Electrocoated panels were water rinsed using a spray gun set to shower mode (75° F.) for 30 seconds and then panels were baked in an oven (Despatch Model LFD-1-42) at 177° C. for 25 minutes.
Electrocoated panels were X-scribed on one side of the panel. For corrosion performance evaluation, panels were placed in ASTM G85 A2 testing for a minimum of 1 week (i.e., 7 cycles), CASS (Copper Accelerated Acetic Acid Salt Spray) testing for a minimum of 1 week, or GMW14872 for a minimum of 40 cycles (i.e., 40 days). After the exposure, corroded panels were dried under ambient conditions. The loose coating around the X-scribe was removed by applying a scotch filament tape (3M Industries Adhesives and Tapes Divisions, St. Paul, MN) and pulling it off. Afterwards, the width of exposed metal region along the scribe was recorded for 5 or 12 locations and averaged to assess the corrosion performance of the panel. In cases when scribe creep was too wide or the coating came off while tape pulling, the scribe width was reported as 25 mm (i.e., FAIL) and indicates catastrophic delamination of the electrocoat layer that precluded reliable scribe creep measurements. As used herein, scribe creep refers to the area of paint loss around the scribe either through corrosion or disbondment (e.g., affected paint to affected paint). One skilled in the art understands that there is an inherent variability between conditions of different corrosion tests and that therefore corrosion performance of treated panels may vary from one standardized corrosion test to another (e.g., from ASTM G85 A2 testing to CASS testing).
29 AA6111 panels were treated according to Process A (Table 3), with 6 panels being treated with PT-1, 4 with PT-2, 4 with PT-3, 8 with PT-4, 2 with PT-5, and 5 with PT-6 (comparative). All of the panels were then electrocoated with EPIC 200 FRAP as described above. PT-1 (4 panels), PT-2 (2 panels), PT-3 (2 panels), PT-4 (6 panels), PT-5 (2 panels) and PT-6 (3 panels) were exposed to CASS corrosion testing (20 days) and PT-1 (2 panels), PT-2 (2 panels), PT-3 (2 panels), PT-4 (2 panels), and PT-6 (2 panels) were exposed to ASTM G85 A2 testing (70 cycles). Corrosion performance data are reported in
The data in Example 1 demonstrate that peroxide free compositions PT-1 to PT-5 deliver comparable or better corrosion performance against the peroxide containing cerium-based pretreatment PT-6 (control).
6 CRS panels were treated according to Process A (Table 3), with 2 panels being treated with one of PT-4, PT-5, or PT-6. All of the panels were then electrocoated with EPIC 200 FRAP as described above. All of the panels were exposed to GMW14872 cyclic corrosion testing (40 cycles). Corrosion performance data are reported in
The data in Example 2 demonstrate that peroxide free pretreatment compositions PT-4 and PT-5 deliver comparable or improved corrosion performance against a peroxide containing composition PT-6 (control) on cold rolled steel substrate.
28 AA6111 panels were treated according to Process B (Table 3). All panels were treated with DX-1 followed by treatment with one of the pretreatment compositions as described above, with 8 panels being treated with PT-1, 4 panels being treated with PT-2, 4 panels being treated with PT-3, 6 panels being treated with PT-4, and 6 panels being treated with PT-6 (comparative). All of the panels were then electrocoated with EPIC 200 FRAP as described above. PT-1 (6 panels), PT-2 (2 panels), PT-3 (2 panels), PT-4 (4 panels), and PT-6 (4 panels) were exposed to CASS corrosion testing (20 days) and PT-1 (2 panels), PT-2 (2 panels), PT-3 (2 panels), PT-4 (2 panels), and PT-6 (2 panels) were exposed to ASTM G85 A2 testing (70 cycles). Corrosion performance data are reported in
The data in Example 3 demonstrate that peroxide free cerium-based compositions PT-1 to PT-4 deliver a comparable corrosion performance against a peroxide containing pretreatment composition PT-6 (control).
20 AA6022 panels were treated according to Process B (Table 3). All panels were treated with DX-1 followed by pretreatment with one of the pretreatment compositions as described above, with 4 panels being treated with one of PT-1 to PT-4 and 4 with comparative composition PT-6. All of the panels were then electrocoated with EPIC 200 FRAP as described above. 2 panels with one of these compositions were exposed to CASS corrosion testing (27 days) and 2 panels with each of these pretreatment compositions were exposed to ASTM G85 A2 testing (42 cycles). Corrosion performance data are reported in
The data in Example 4 demonstrate that peroxide free cerium-based compositions PT-1 to PT-4 deliver a comparable corrosion performance against a peroxide containing pretreatment composition PT-6 (control).
4 AA6111 panels were treated according to Process B (Table 3). All panels were treated with DX-3 followed by pretreatment with one of the pretreatment compositions as described above, with 2 panels being treated with PT-1 and 2 panels being treated with PT-6. All of the panels were then electrocoated with EPIC 200 FRAP as described above. All of the panels were exposed to CASS corrosion testing (20 days). Corrosion performance data are reported in
The data in Example 5 demonstrate that peroxide free treatment composition PT-1 in combination with DX-3 deoxidizer delivers a comparable corrosion performance as observed with peroxide containing pretreatment composition PT-6 (control) and DX-3 deoxidizer.
4 CRS panels were treated according to Process B (Table 3). All panels were treated with DX-3 followed by pretreatment with one of the pretreatment compositions as described above, with 2 panels being treated with PT-1 and 2 panels being treated with PT-6. All of the panels were then electrocoated with EPIC 200 FRAP as described above. All of the panels were exposed to GMW14872 corrosion testing (40 cycles). Corrosion performance data are reported in
The data in Example 6 demonstrate that peroxide free composition PT-1 in combination with DX-3 deoxidizer delivers a comparable corrosion performance as observed with peroxide containing pretreatment composition PT-6 (control) and DX-3 deoxidizer.
10 AA6111 panels were treated according to Process B (Table 3), with 6 panels being treated with DX-1, 2 panels with DX-2, and 2 panels with DX-3 and all panels being treated with PT-1. All of the panels were then electrocoated with EPIC 200 FRAP as described above. All of the panels were exposed to CASS corrosion testing (20 days). Corrosion performance data are reported in
The data in Example 7 demonstrate that peroxide free cerium composition PT-1 preceded by silicon-based deoxidizer (DX-2) exhibits better corrosion protection than that by PT-1 preceded by zirconium-based deoxidizer (DX-1). Copper addition in deoxidizer DX-2 (i.e., DX-3 deoxidizer) further enhances the corrosion protection of PT-1.
8 AA6111 panels were treated according to Process C (Table 3), with 4 panels being treated with PT-7 only and 4 panels being treated with PT-7 followed by PT-1. All of the panels were then electrocoated with EPIC 200 FRAP as described above. 2 panels from each of these two sets were exposed to CASS corrosion testing (20 days) and 2 panels from each of these two sets were exposed to ASTM G85 A2 testing (42 cycles). Corrosion performance data are reported in
The data in Example 8 demonstrate that treatment of a substrate with a cerium-containing composition that is free of peroxide following pretreatment with a zirconium-containing pretreatment composition enhances the corrosion performance.
This application claims priority to U.S. Provisional Patent Application Ser. No. 63/163,353, filed on Mar. 19, 2021, and entitled “Systems and Methods for Treating a Substrate,” incorporated in its entirety herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2022/012961 | 1/19/2022 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63163353 | Mar 2021 | US |
