RU2721259C1 - Preparation of treatment composition and bath maintenance system and method for treatment formed therefrom - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to processing compositions intended for forming a protective coating on the surface of substrates, as well as to preparation of such compositions and to methods for maintaining baths for treatment formed from said treatment compositions. Method of producing a treatment composition for forming a protective coating on a substrate containing lithium carbonate involves a reaction of lithium cation and a carbon dioxide source in an aqueous medium to obtain a treatment composition. Said treatment composition contains lithium cation in amount of 5 ppm to 5,500 ppm, with respect to lithium cation, based on total weight of treatment composition, and an anion of carbonate in amount of 15 ppm to 25,000 ppm, based on the anion of carbonate, based on the total weight of the treatment composition. Substrate treated with the composition obtained by said method. Method of preparing a bath for forming a protective coating on a substrate containing said treatment composition comprises feeding into the bath during and/or after treatment of the substrate in said bath of at least one of a carbon dioxide source and a lithium source in an amount sufficient to maintain the pH of the treatment composition from 9.5 to 12.5. Substrate treated in a bath containing a composition containing lithium carbonate to form a protective coating, wherein said bath is prepared using said method.

EFFECT: providing treatment compositions which are environmentally safe and harmless to health, which can be obtained in a cost-effective manner from readily available resources, and can form a protective layer, which provides effective protection against corrosion and having a suitable adhesion on the surface of the substrate, comparable to compositions containing phosphates and/or chromates.

16 cl, 3 dwg, 6 tbl, 13 ex

Description

Cross reference to related applications

This application claims priority on provisional application US No. 62 / 374,188, filed August 12, 2016 and entitled "Sealing Composition" ("Sealing composition"), and provisional application US No. 62 / 526,382, filed June 29, 2017 and entitled "Preparation of Treatment Composition and System and Method of Maintaining a Treatment Bath Formed Therefrom ",

FIELD OF THE INVENTION

The present invention relates to processing compositions for processing substrates, such as metal substrates, such as processing compositions for forming a protective coating on a surface, as well as to the preparation of such compositions and systems, and to methods for maintaining treatment baths formed from such processing compositions.

State of the art

The use of protective coatings on metal surfaces to improve the corrosion resistance and paint adhesion characteristics is well known in the field of metal finishes. Conventional techniques include treating metal substrates with treatment compositions containing phosphate and chromium to increase the corrosion resistance and adhesion of the coating formed by the treatment composition to the surface of the substrate. However, the use of such phosphate and / or chromate-containing compositions poses environmental and health problems. As a result, processing compositions free of chromates and / or phosphates were developed.

During a typical treatment process, when the processing composition is in contact with the substrate, some ingredients, such as metal ions in the processing composition, are deposited on the surface of the substrate or bonded to it, forming a protective layer. As a result, the concentration of these ions in the composition may decrease during the process, which may adversely affect the performance and reproducibility of the coating among substrates sequentially coated in the same coating composition. Accordingly, it is necessary to create processing compositions that do not pose problems for the environment and health, and can be used to form protective coatings having effective anticorrosion and adhesive characteristics on the surface of the substrate, and means to avoid or at least reduce composition variations with ongoing the use of such processing compositions of the substrates and the associated adverse effects on the characteristics and reproducibility of the coating. Therefore, the present invention is directed to the creation of processing compositions that are environmentally friendly and harmless to health, can be obtained in a cost-effective way from readily available resources, and at the same time they can form a protective layer that provides effective corrosion protection and has suitable adhesion on the surface of the substrate, comparable to compositions containing phosphates and / or chromates.

Another goal is to provide a method and system that enables the continued use of treatment baths formed from such compositions for treating substrates that produce coatings with desired characteristics in a reproducible manner without compositional variations affecting corrosion or adhesion characteristics.

Disclosure of invention

These problems are solved using the processing composition and the method of its manufacture, as well as the method and system for maintaining the bath for processing, as indicated in the attached claims and set forth in more detail in the following description.

The processing compositions described herein typically contain a carbon dioxide source, a lithium cation, which may be in the form of a lithium salt, and an aqueous medium.

The processing composition may contain lithium carbonate, wherein lithium carbonate can be formed by reacting carbon dioxide and lithium cation in situ in an aqueous medium.

Thus, the present invention relates to a method for manufacturing a treatment composition comprising combining lithium cation and carbon dioxide in an aqueous medium to form a treatment composition containing lithium in an amount of from 5 ppm to 5500 ppm (based on lithium cation) based on the total weight of the processing composition, and carbonate in an amount of from 15 ppm to 25,000 ppm (based on carbonate) based on the total weight of the processing composition.

The present invention further relates to a system for maintaining a treatment bath formed from a treatment composition comprising lithium carbonate, the system comprising a lithium salt; and / or carbon dioxide; and, if necessary, a source of hydroxide.

Also part of the present invention is a method for maintaining a treatment bath formed from a processing composition comprising lithium carbonate, the method comprising supplying, at the time and / or after processing the substrate of said bath, at least one of carbon dioxide and lithium salt to the bath in an amount sufficient to maintain the pH of the bath for processing at a level of from 9.5 to 12.5, lithium in an amount of from 5 ppm to 5500 ppm (calculated on lithium cation) based on the total weight of the bath for processing, and carbonate in an amount of 15 ppm to 25,000 ppm (when calculated on carbonate) based on the total weight of the bath for processing.

In addition, the present invention relates to substrates treated with such compositions and supported bathtubs for processing. The coating characteristics and reproducibility of coatings formed on substrates treated with such compositions and supported by treatment baths are more uniform on sequentially processed substrates than the coating characteristics and reproducibility of coatings formed on substrates treated with compositions that were not formed or supported in this way. Accordingly, protective coatings formed from the compositions and treatment baths supported in accordance with the present invention are reproducible and exhibit suitable corrosion characteristics and adhesion to the surface of the substrate.

Brief Description of the Drawings

Figure 1 is a flowchart detailing the sequential steps used to prepare processing baths containing the processing compositions used in Examples D to J.

2 is a flowchart detailing the sequential steps used to prepare processing baths containing the compositions used in Examples L-O.

3 is a diagram illustrating a layer thickness of a processing composition on a substrate surface.

The implementation of the invention

For the purposes of the following detailed description, it should be understood that the invention may contemplate various alternatives and sequences of steps, unless expressly indicated otherwise. Further, except in any working examples or where indicated otherwise, all numbers, such as numbers expressing values, quantities, percentages, ranges, subranges and fractions, may be read as if they were preceded by the word “approximately”, even if this the term is not explicitly stated. Accordingly, unless otherwise indicated, the numerical parameters set forth in the following description and the attached claims are approximate values, which may vary depending on the desired properties to be obtained using 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 conventional rounding methods. If a closed or open numerical range is described here, then all numbers, values, quantities, percentages, subranges and fractions within or within the scope of the numerical range should be construed as expressly included in the initial disclosure of this application and their values, as if these numbers, amounts, percentages, subranges and fractions were clearly recorded in their entirety.

Although the numerical ranges and parameters defining the broad scope of the invention are approximate, the numerical values set forth in the specific examples are reported as accurately as possible. However, any numerical value by its nature contains certain errors that inevitably arise as a result of the standard deviation found in their respective test measurements.

Used here, unless otherwise indicated, the term plural may cover its singular and vice versa, unless otherwise specified. For example, although reference is made here to the “lithium salt”, “hydroxide”, and “processing composition” in the singular, 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 indicated otherwise, even if “and / or” may be explicitly used in certain cases.

The terms “comprising”, “comprising” and the like, used in this application, are understood in the context of this application as a synonym for the term “comprising” and, therefore, are open and do not exclude the presence of additional undescribed and / or unclaimed elements, materials, ingredients and / or process steps. As used herein, the term “consisting of” is understood in the context of this application to exclude the presence of any vague element, ingredient and / or process step. As used herein, the term “consisting essentially of” is understood in the context of the present application to include the indicated elements, materials, ingredients and / or process steps “and those that do not substantially affect the main and new characteristic (s)” of what is currently time is described.

Used in this application, the terms “on”, “k”, “applied”, “deposited on”, “formed on”, “applied on”, “deposited on”, mean formed, superimposed, applied and / or secured on, but not necessarily in contact with the surface. For example, a coating layer “formed over” a substrate does not exclude the presence of one or more other intermediate coating layers of the same or different composition located between the formed coating layer and the substrate.

Unless otherwise disclosed herein, the term “substantially free” when used with respect to the absence of a specific material means that such material, if any, is present in the composition, the bath containing the composition and / or the layers formed from and containing the composition is present only in trace amounts of 5 ppm or less, depending on the total weight of the composition, bath or layer (s), depending on the circumstances. Unless otherwise disclosed herein, the term “substantially free” when used with respect to the absence of a specific material means that such material, if any, is present in the composition, the bath containing the composition and / or the layers formed from the composition and containing the composition, only in a trace amount of 1 ppm or less, based on the total weight of the composition, bath or layer (s), as the case may be. Unless otherwise disclosed herein, the term “completely free” when used with respect to the absence of a specific material means that such material, if present at all in the composition, the bath containing the composition and / or the layers formed from the composition and containing the composition, is absent the composition, the bath containing the composition and / or the layers formed from and including it (i.e., the composition, the bath containing the composition and / or the layers formed from the composition and containing the composition, contain 0 ppm of such material ) When a composition, a bath containing the composition, and / or the layer (s) formed and containing it are substantially free, practically free, or completely free of a particular material, this means that such material is excluded from them, except that the material may be present as a result of, for example, transfer from previous bathtubs for processing in a production line, sources of tap water, a substrate (s) and / or equipment wear.

As used herein, the term “salt” refers to an ionic compound formed from metal cations and nonmetallic anions and having a total electric charge of zero. Salts may be hydrated or anhydrous.

As used herein, the term “aqueous composition” refers to a solution or dispersion in a medium that contains predominantly water. For example, the aqueous medium may contain 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 medium. The aqueous medium may, for example, consist essentially of water.

As used herein, the term “oxidizing agent” when used with respect to a component of a sealant composition refers to a chemical that is capable of oxidizing at least one of the metal present in the substrate with which the sealant is in contact and / or the metal complexing agent present in the sealing composition. When used with respect to the term “oxidizing agent”, the phrase “oxidizable” means the ability to remove electrons from an atom or molecule present in a substrate or in a sealing composition, as the case may be, thereby reducing the number of electrons.

As used herein, the term “Group IA metal” refers to an element that is located in Group IA of the CAS version of the Periodic Table of the Elements, as shown, for example, in “Handbook of Chemistry and Physics”, 63rd edition (1983), corresponding to group 1 in the current IUPAC numbering.

As used herein, the term “compound of a metal of group IA” refers to compounds that contain at least one element that is in group IA of the CAS version of the Periodic Table of the Elements.

As used in this application, the term “Group IIA metal” refers to an element of Group IIA in the CAS version of the Periodic Table of Elements, as shown, for example, in “Handbook of Chemistry and Physics”, 63rd edition (1983), corresponding to group 2 in current IUPAC numbering.

As used herein, the term “Group IIA metal compound” refers to compounds that contain at least one element that is in group IIA of the CAS version of the Periodic Table of the Elements.

As used in this application, the term “Group IIIB metal” refers to yttrium and scandium in the CAS version of the Periodic Table of the Elements, as shown, for example, in the Handbook of Chemistry and Physics, 63rd edition (1983), corresponding to group 3 in current IUPAC numbering. For clarity, the “Group IIIB metal” explicitly excludes elements of the lanthanide family.

As used herein, the term “Group IIIB metal compound” refers to compounds that contain at least one element that is in group IIIB of the CAS version of the Periodic Table of the Elements as defined above.

As used herein, the term “Group IVB metal” refers to an element that is located in Group IVB of the CAS version of the Periodic Table of the Elements, as shown, for example, in Handbook of Chemistry and Physics, 63rd edition (1983), corresponding to Group 4 in the current IUPAC numbering.

As used herein, the term “Group IVB metal compound” refers to compounds that contain at least one element that is in the IVB group of the CAS version of the Periodic Table of the Elements.

As used herein, the term “VB group metal” refers to an element that is in the VB group of the CAS version of the Periodic Table of Elements, as shown, for example, in “Handbook of Chemistry and Physics,” 63rd ed. (1983), which corresponds to group 5 in the current IUPAC numbering.

As used herein, the term “VB group metal compound” refers to compounds that contain at least one element that is in the VB group of the CAS version of the Periodic Table of the Elements.

As used in this application, the term “metal of the VIB group” refers to an element that is in the VIB group of the CAS version of the Periodic Table of Elements, as shown, for example, in “Handbook of Chemistry and Physics”, 63rd edition (1983), corresponding to group 6 in the current IUPAC numbering.

As used herein, the term “Group VIB metal compound” refers to compounds that contain at least one element that is in the VIB group of the CAS version of the Periodic Table of the Elements.

As used herein, the term “Group VIIB metal” refers to an element that is in group IA of the CAS version of the Periodic Table of the Elements, as shown, for example, in “Handbook of Chemistry and Physics”, 63rd edition (1983), corresponding to group 7 in the current IUPAC numbering.

As used herein, the term “Group VIIB metal compound” refers to compounds that contain at least one element that is included in Group VIIB of the CAS version of the Periodic Table of the Elements.

As used herein, the term “Group XII metal” refers to an element that is in group IA of the CAS version of the Periodic Table of the Elements, as shown, for example, in “Handbook of Chemistry and Physics”, 63rd edition (1983), corresponding to group 12 in the current IUPAC numbering.

As used herein, the term “Group XII metal compound” refers to compounds that contain at least one element that is in group XII of the CAS version of the Periodic Table of the Elements.

Used in this application, the term "elements of the lanthanide family" refers to elements 57-71 of the CAS version of the Periodic system of elements and includes elemental versions of the elements of the lanthanide family. In accordance with the present invention, elements of the lanthanide family can be those that have both common oxidation states of +3 and +4, hereinafter referred to as + 3 / + 4 oxidation states.

As used herein, the term “lanthanoid compound” refers to compounds that contain at least one of the elements 57-71 of the CAS version of the Periodic Table of the Elements.

As used herein, the term “sealing composition” refers to a composition, for example, a solution or dispersion, that acts on a surface of a substrate or a material deposited on a surface of a substrate, so as to alter the physical and / or chemical properties of the surface of the substrate (for example, the composition provides corrosion protection).

As used herein, the term “conversion composition” refers to a composition, for example, a solution or dispersion that is capable of reacting with the surface of the substrate and chemically altering the surface of the substrate and bonding to it to form a film that provides corrosion protection.

As used herein, the term “treatment bath” refers to a water bath formed from a parent processing composition. The treatment bath may contain components that are by-products of the process of contacting the substrate with the treatment composition.

As used herein, the term “maintaining” a treatment bath formed from a treatment composition refers to maintaining certain treatment bath parameters, including the concentration of certain ingredients and / or pH, in the desired ranges. This can be achieved, as described in more detail below, by adding one or more materials from an appropriate source to the treatment bath at work and / or outside of work. As used herein, the term “at work” means that the article to be treated is present in the treatment bath. As used herein, the term “out of work” means that the product to be exposed to the treatment composition is not present in the treatment bath, but does not mean that the treatment bath is necessarily removed from the processing line.

Pitting corrosion is a localized formation of corrosion in which cavities or holes form in the substrate. The term "corrosion center" as used in this application refers to such cavities or holes resulting from pitting corrosion and is characterized by (1) a rounded, oblong or uneven appearance when viewed at right angles to the surface of the test panel, (2) the shape of comet’s tail, line, or “halo” (i.e., surface discoloration) emanating from pitting, and (3) the presence of a by-product of corrosion (eg, white, grayish or black granular, powdery, or amorphous material) inside or immediately around the corrosion centers. The observed surface cavity or hole must exhibit at least two of the above characteristics in order to be considered a hotbed of corrosion. Surface cavities or holes that have only one of these characteristics may require additional analysis before classifying them as a corrosion focus. Visual inspection using a microscope with a 10x magnification is used to determine the presence of corrosion by-products when the corrosion by-products are not visible to the naked eye.

Unless otherwise specified herein, the terms “total weight of a composition”, “total weight of a bath”, “total weight of a bath for processing” or similar terms as used herein refer to the total weight of all ingredients present in the corresponding composition, including any carriers and solvents .

As mentioned above, according to the present invention, a processing composition comprising lithium carbonate is disclosed. Lithium carbonate, in particular, can be formed in situ, as described above, by reacting carbon dioxide and a lithium cation, which may be in the form of a lithium salt, for example, in an aqueous medium. The processing composition may be a sealing composition, a conversion composition, or the like.

The processing composition of the present invention is usually alkaline. According to the present invention, the pH of the processing composition can be at least 9.5, for example at least 10, for example at least 11, and in some cases, can be no more than 12.5, for example, no more than 12, for example, no more than 11.5. According to the present invention, the pH of the processing composition can be from 9.5 to 12.5, for example from 10 to 12, for example from 11 to 11.5. According to the present invention, the pH of the treatment composition can be adjusted by incorporating an acidic material, including carbon dioxide, water-soluble and / or water-dispersible acids, such as nitric acid, sulfuric acid and / or phosphoric acid. According to the present invention, the pH of the treatment composition can be adjusted by incorporating a base material, including water soluble and / or water dispersible bases, including carbonates such as group I carbonates, group II carbonates, hydroxides such as lithium hydroxide, sodium hydroxide, potassium hydroxide or hydroxide ammonia, ammonia and / or amines, such as triethylamine, methylethylamine or mixtures thereof.

According to the present invention, the carbon dioxide used to form the treatment composition of the present invention may be a gas, a solid (i.e., dry ice), or a combination thereof.

According to the present invention, the lithium salt used to form the processing composition of the present invention may comprise an inorganic lithium salt, an organic lithium salt, or combinations thereof. According to the present invention, the anion and cation of a lithium salt can be soluble in water. According to the present invention, the lithium salt may have a solubility constant in water at a temperature of 25 ° C (K; 25 ° C) of at least 1 × 10 ^-11 , for example, at least 1 × 10 ^-4 , and in some cases may be no more than 5x10 ⁺² . According to the present invention, the lithium salt may have a solubility constant in water at a temperature of 25 ° C (K; 25 ° C) from 1 × 10 ⁻¹¹ to 5 × 10 ⁺² , for example, from 1 × 10 ^-4 to 5 × 10 ^{+ 2} . As used herein, the term “solubility constant” means a product of equilibrium ion concentrations in a saturated aqueous solution of the corresponding lithium salt. Each concentration rises to the power of the corresponding ion coefficient in the balance equation. Solubility constants for various salts can be found in the Handbook of Chemistry and Physics. Examples of suitable lithium salts are lithium carbonate, lithium hydroxide, lithium phosphate, lithium sulfate and lithium tetraborate.

If necessary, the processing composition may also contain hydroxide, such as alkali metal hydroxide, alkaline earth metal hydroxide, or a combination thereof. According to the present invention, the hydroxide may be one or more group I hydroxides, ammonium hydroxide, or mixtures thereof. Hydroxide, if present at all, may be present in any quantity, for example, in an amount at which the pH of the processing composition remains in the range from 9.5 to 12.5. Non-limiting examples of Group I hydroxides include sodium hydroxide, potassium hydroxide, lithium hydroxide, or mixtures thereof. Accordingly, the hydroxide, if used, can be supplied as a component of a lithium salt used to form a processing composition or part thereof, for example lithium hydroxide, if necessary in combination with other lithium salts, such as lithium carbonate. However, the processing composition may also contain one or more hydroxides other than lithium salts, such as, for example, sodium hydroxide, potassium hydroxide, or a combination thereof.

The processing composition of the present invention typically contains an aqueous medium as a carrier. Thus, the composition may be in the form of a solution or dispersion of a lithium salt in a carrier.

According to the present invention, lithium carbonate is formed by combining carbon dioxide and lithium cation in an aqueous carrier medium, where carbon dioxide and lithium cation are balanced to be present in such amounts that lithium is present in the processing composition in an amount of from 5 ppm up to 5500 ppm (when calculated on lithium cation) based on the total weight of the processing composition, and carbonate was present in the processing composition in an amount from 15 ppm to 25000 ppm (calculated on carbonate) the total mass of the processing composition. As indicated above, if necessary, additionally one or more pH modifiers, such as one or more acidic materials and / or one or more basic materials, such as one or more hydroxides, are added to the aqueous medium of the carrier, where amounts of such an optional modifier (s ) pH, carbon dioxide and lithium salts can be balanced so that the pH of the processing composition was 9.5-12.5.

According to the present invention, the processing composition may further comprise at least one group IA metal cation other than lithium, a group VB metal cation and / or a group VIB metal cation. According to the present invention, at least one group IA metal cation other than lithium, group VB metal cation and / or group VIB metal cation may be in salt form, and each cation may be present in the treatment composition in an amount of at least 5 hours. / million, such as at least 50 ppm, such as at least 150 ppm, such as at least 250 ppm (based on metal cation) based on the total weight of the processing composition, and in some cases, may be present in an amount of not more than 5500 ppm, such as not more than 1200 ppm, such as not more than 1000 ppm, such as not more than 500 ppm (based on cation metal) based on the total weight of the processing composition. In some cases, in accordance with the present invention, lithium metal may be present in the processing composition in an amount of from 5 ppm to 5500 ppm, such as from 50 ppm to 1000 ppm (based on metal cation) based on the total weight of the processing composition, such as from 150 ppm to 500 ppm.

Non-limiting examples of anions suitable for salt formation with lithium cations, non-lithium cations of group IA, group VB cations and / or group VIB cations include carbonates, hydroxides, nitrates, halogens, sulfates, phosphates and silicates (e.g., orthosilicates and metasilicates ), so that the metal salt may include carbonate, hydroxide, nitrate, halide, sulfate, phosphate, silicate (for example, orthosilicate or metasilicate), permanganate, chromate, vanadate, molybdate and / or perchlorate.

According to the present invention, each of the metal salts of the processing composition (i.e., lithium salts of metals of group IA other than lithium, group VB and / or group VIB) may be present in the processing composition in an amount of at least 25 ppm, such as at least 150 ppm, such as at least 500 ppm (based on the total amount of compound) based on the total weight of the processing composition, and in some cases not more than 30,000 ppm, such as not more than 2000 ppm, such as not more than 1500 ppm (based on the total amount of compound) based on the total weight of the processing composition. According to the present invention, each of the metal salts may be present in the processing composition in an amount of from 25 ppm to 30,000 ppm, such as from 150 ppm to 2000 ppm, such as from 500 ppm. million up to 1,500 ppm (when calculating the total amount of compound) based on the total weight of the processing composition.

According to the present invention, the sealing composition of the present invention may contain an oxidizing agent such as hydrogen peroxide, persulfates, perchlorates, bubble oxygen, bromates, peroxybenzoates, ozone and the like, or combinations thereof. For example, the sealing composition may contain from 0.1 to 15 wt.% The oxidizing agent, based on the total weight of the sealing composition, for example, from 2 to 10 wt.%, For example, from 6 to 8 wt.%. Alternatively, according to the present invention, the sealing composition may be substantially free, or in some cases substantially free, or in some cases completely free of oxidizing agent.

According to the present invention, the processing composition may exclude chromium or chromium-containing compounds. As used herein, the term “chromium-containing compound” refers to materials that include hexavalent chromium. Non-limiting examples of such materials include chromic acid, chromium trioxide, chromic anhydride, dichromate salts such as ammonium dichromate, sodium dichromate, potassium dichromate, and dichromate of calcium, barium, magnesium, zinc, cadmium and strontium. When a treatment composition and / or bath, or a coating or layer, respectively, formed therefrom is substantially free, substantially free, or completely free of chromium, this includes chromium in any form, such as the compounds containing hexavalent chromium listed above, but not limited to this.

Thus, if necessary, according to the present invention, the present processing compositions and / or baths for processing and / or coatings or layers, respectively, deposited from them, can be essentially free, practically free and / or completely free from one or more of any elements or compounds listed in the previous paragraph. A treatment composition and / or bath and / or coating or layer formed therefrom which is substantially free of chromium or chromium-containing compounds means that chromium or chromium-containing compounds are not intentionally added, but may be present in trace amounts, for example due to impurities or inevitable pollution from the environment. In other words, the amount of material is so small that it does not affect the properties of the processing composition and / or the bath and / or coating or layers formed from it; in the case of chromium, this may further include the fact that the element or its compounds are not present in the processing compositions and / or the bath and / or coatings or layers, respectively, formed from them, at such a level that it causes a load on the environment. The term "essentially free" means that the processing compositions and / or bathtubs and / or coating or layers formed therefrom contain less than 10 ppm of any or all of the elements or compounds listed in the previous paragraph, based on the total weight composition or layer, respectively, if any. The term “substantially free” means that the processing compositions and / or baths and / or coatings or layers formed therefrom contain less than 1 ppm of any or all of the elements or compounds listed in the previous paragraph, based on the total weight of the composition , bathtubs of a coating or layer, as the case may be, if at all. The term "completely free" means that the processing compositions and / or baths and / or coatings or layers formed therefrom contain less than 1 ppm of any or all of the elements or compounds listed in the previous paragraph, based on the total weight of the composition , baths, coatings or coatings, as appropriate, if any.

According to the present invention, the present treatment compositions and / or baths for processing and / or coatings or layers formed therefrom, in some cases, exclude phosphate ions or phosphate-containing compounds and / or sludge formation, such as aluminum phosphate, iron phosphate and / or zinc phosphate resulting from the use of a processing agent based on zinc phosphate. As used herein, the term “phosphate-containing compounds” includes compounds containing a phosphorus element, such as orthophosphate, pyrophosphate, metaphosphate, tripolyphosphate, organophosphonates and the like, and may include monovalent, divalent or trivalent cations, such as sodium, potassium, calcium , zinc, nickel, manganese, aluminum and / or iron, but not limited to. When the treatment composition and / or bath and / or layers or coatings containing it are substantially free, substantially free, or completely free of phosphate, this includes phosphate ions or compounds containing phosphate in any form.

Thus, according to the present invention, the treatment compositions and / or baths and / or coatings or layers applied therefrom can be substantially free, or in some cases can be substantially free, or in some cases can be completely free of one or several of any ions or compounds listed in the previous paragraph. Processing compositions and / or baths and / or coatings or layers deposited therefrom that are substantially phosphate-free, mean that phosphate ions or phosphate-containing compounds are not intentionally added, but may be present in trace amounts, for example, for impurities or inevitable pollution 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 the fact that phosphate is not present in the processing compositions and / or baths and / or coatings or layers deposited therefrom at such a level that they create an environmental burden. The term "essentially free" means that the processing compositions and / or baths and / or coatings or layers deposited therefrom contain less than 5 ppm of any or all of the phosphate anions or compounds listed in the previous paragraph, calculated the total weight of the composition, bath, coating or layer, respectively, if any. The term “substantially free” means that the treatment compositions and / or baths and / or coatings or layers formed from them contain less than 1 ppm of any or all of the phosphate anions or compounds listed in the previous paragraph, based on the total the mass of the composition, bath, coating or layer, respectively, if any. The term "completely free" means that the processing compositions and / or baths and / or coatings or layers formed from them contain less than 1 ppm of any or all of the phosphate anions or compounds listed in the previous paragraph, based on the total the mass of the composition, bath, coating or layer, respectively, if any.

According to the present invention, the sealing composition may exclude cations of Group IIA metals or compounds containing Group IIA metals, including but not limited to calcium. Non-limiting examples of such materials include group IIA metal hydroxides, group IIA metal nitrates, group IIA metal halides, group IIA metal sulfamates, group IIA metal sulfates, group IIA carbonates and / or group IIA metal carboxylates. When the sealant composition and / or coating or layer, respectively, formed therefrom is substantially free, substantially free, or completely free of a Group IIA metal cation, this includes Group IIA metal cations in any form, such as compounds containing Group IIA metals, listed above, but not limited to.

According to the present invention, the sealing composition in some cases may exclude fluoride or fluoride sources. As used herein, the term “fluoride sources” includes monofluorides, difluorides, fluoride complexes and mixtures thereof, which are known to generate fluoride ions. When the composition and / or layer or coating containing it is substantially free, substantially free, or completely free of fluoride, this includes fluoride ions or fluoride sources in any form, but does not include the unintentional fluoride that may be present in the bath as a result for example, transferring from previous bathtubs for processing in a processing line, from sources of tap water (e.g., fluoride added to water to prevent tooth decay), fluoride from a pretreated substrate, or the like. That is, a bath that is substantially free, substantially free or completely free of fluoride may contain unintentional fluoride, which can be obtained from these external sources, even though the composition used to make the bath before use on the production line was essentially free, practically free or completely free of fluoride.

For example, the sealant composition may be substantially free of any sources of fluorides, such as ammonium and alkali metal fluorides, acid fluorides, fluoroboric, silicic, fluorotitanic and fluorozirconic acids, as well as their ammonium salts and alkali metal salts and other inorganic fluorides; non-exceptional examples of which are zinc fluoride, zinc-aluminum fluoride, titanium fluoride, zirconium fluoride, nickel fluoride, ammonium fluoride, sodium fluoride, potassium fluoride and hydrofluoric acid, as well as other similar materials known to those skilled in the art.

Fluoride present in a sealant composition that is not bound to metal ions, such as Group IVB metal ions, or a hydrogen ion, defined herein as “free fluoride”, can be measured as an operating parameter in the bath of the sealant composition using, for example, two-channel An Orion Dual Star Bench Top Meter equipped with a Fluoride Selective Electrode ("ISE") supplied by Thermoscientific, a Symphony® Fluoride Selective Combination Electrode supplied by VWR International, or similar. See, for example, Light and Cappuccino, “Determination of fluoride in toothpaste using an ion-selective electrode”, J. Chem. Educ., 52: 4, 247-250, April 1975. A fluoride-selective electrode can be standardized by immersing the electrode in solutions of known fluoride concentration and recording readings in millivolts, and then displaying these readings in millivolts on a logarithmic graph. The millivolt reading of the unknown sample can then be compared with this calibration graph and the fluoride concentration determined. Alternatively, a fluoride-selective electrode can be used with a meter that will perform internal calibration calculations, and thus, after calibration, the concentration of the unknown sample can be read directly.

Fluoride ion is a small negative ion with a high charge density; therefore, in an aqueous solution it often forms a complex with metal ions having a high positive charge density, such as Group IVB metal ions or with a hydrogen ion. Fluoride anions in solution that are ionically or covalently bonded to metal cations or a hydrogen ion are defined herein as “bound fluoride”. The fluoride ions that form such complexes cannot be measured with a fluoride-ion selective electrode if the solution in which they are present is not mixed with an ionic strength correction buffer (e.g. citrate anion or EDTA) that releases fluoride ions from such complexes. At this point (all) fluoride ions can be measured with a fluoride-ion selective electrode, and the result of the determination is known as “total fluoride”. Alternatively, total fluoride can be calculated by comparing the mass of fluoride provided in the sealant composition with the total weight of the composition.

In accordance with the present invention, the processing composition may in some cases be substantially free, or in some cases substantially free, or in some cases completely free of cobalt ions or cobalt-containing compounds. As used herein, the term “cobalt-containing compounds” includes compounds, complexes or salts containing a cobalt element, such as, for example, cobalt sulfate, cobalt nitrate, cobalt carbonate and cobalt acetate. When the composition and / or layer or coating containing it is substantially free, substantially free or completely free of cobalt, this includes cobalt ions or compounds containing cobalt in any form.

According to the present invention, the treatment composition may in some cases be substantially free, or in some cases substantially free, or in some cases completely free of vanadium ions or vanadium-containing compounds. As used herein, the term “vanadium-containing compounds” includes compounds, complexes or salts containing a vanadium element, for example, such as vanadates and decavanadates, which include alkali metal counterions or ammonium cations, including, for example, sodium-ammonium decavanadate. When a composition and / or layer or coating containing it is substantially free, substantially free or completely free of vanadium, this includes vanadium ions or compounds containing vanadium in any form.

According to the present invention, the processing composition may further comprise an indicator compound, so named because it indicates, for example, the presence of a chemical substance such as a metal ion, the pH of the composition and the like. “Indicator”, “indicator compound” and similar terms used herein refer to a compound that changes color in response to some external stimulus, parameter or condition, such as the presence of a metal ion, or in response to a specific pH or pH range .

The indicator compound used in accordance with the present invention may be any indicator known in the art that indicates the presence of a substance, a particular pH, and the like. For example, a suitable indicator may be an indicator that changes color after the formation of a complex of a metal ion with a specific metal ion. The indicator of metal ions, as a rule, is a highly conjugated organic compound. The term “conjugated compound”, as used herein, and as will be understood by those skilled in the art, refers to a compound having two double bonds separated by a single bond, for example, two carbon-carbon double bonds with a single carbon-carbon bond between them. Any conjugated compound may be used according to the present invention.

Similarly, an indicator compound may be a compound that changes color when the pH changes; for example, a compound may have one color at an acidic or neutral pH and change color at an alkaline pH, or vice versa. Such indicators are well known and widely available for sale. An indicator that "changes color upon transition from the first pH to the second pH" (that is, from the first pH to the second pH, more or less acidic or alkaline), therefore has the first color (or is colorless) when exposed to the first pH and changes to a second color (or changes from colorless to colored) upon transition to a second pH value (that is, one that is more or less acidic or alkaline than the first pH value). For example, an indicator that “changes color when it changes to a more alkaline pH (or less acidic pH) changes from the first color / colorless to the second color when the pH changes from acidic / neutral to alkaline. For example, an indicator that “changes color when changing to a more acidic pH (or less alkaline pH) changes from the first color / colorless to the second color when the pH changes from alkaline / neutral to acidic.

Non-limiting examples of such indicator compounds include methyl orange, xylenol orange, catechol violet, bromphenol blue, green and violet, Eriochrome black T, celestin blue, hematoxylin, calmagite, gallocyanin, and combinations thereof. If necessary, the indicator compound may contain an organic indicator compound, which is an indicator of a metal ion. Non-limiting examples of indicator compounds include those shown in Table 1. Fluorescent indicators that emit light under certain conditions can also be used in accordance with the present invention, although the use of a fluorescent indicator can also be specifically excluded. That is, alternatively, conjugated compounds that exhibit fluorescence are specifically excluded. As used herein, the term “fluorescent indicator” and similar terms refer to compounds, molecules, pigments and / or dyes that fluoresce or otherwise show color when exposed to ultraviolet or visible light. By "fluorescence" is meant light emission after absorption of light with a shorter wavelength or other electromagnetic radiation. Examples of such indicators, often referred to as “tags”, include acridine, anthraquinone, coumarin, diphenylmethane, diphenylnaphthylmethane, quinoline, stilbene, triphenylmethane, anthracin and / or substances containing any of these components and / or derivatives of any of them, such as rhodamines, phenanthridines, oxazines, fluorones, cyanines and / or acridines.

Table 1

Compound Structure CAS No. Catechol purple
Synonyms:
Catecholsulfonphthalein; Pyrocatecholsulfonphthalein;
Catechol violet

115-41-3 Xylenol Orange
Synonym:
3,3′-Bis [N, N-bis (carboxymethyl) aminomethyl] -
o-cresolsulfonphthalein tetrasodium salt

3618-43-7

In accordance with the present invention, the conjugated compound used as an indicator may, for example, contain catechol violet, as shown in Table 1. Catechol violet (CV) is a sulfonphthalein dye obtained by condensation of two moles of catechol with one mole of anhydride o Sulfobenzoic acid. It was found that CV has indicator properties, and when included in compositions containing metal ions, forms complexes, which makes it useful as a complexometric reagent. Since a composition containing CV chelates metal ions coming from a metal substrate (that is, having a divalent or higher valency), a color from blue to blue-violet is usually observed.

Xylenol orange, as shown in Table 1, can also be used in the compositions of the present invention. It was found that xylenol orange has indicator properties for metal ions (i.e., having a double or higher valency) and when included in compositions containing metal ions, it forms complexes, which makes it useful as a complexometric reagent. Since the composition containing xylenol orange chelates metal ions, the solution of xylenol orange changes from red to usually blue.

According to the present invention, the indicator compound may be present in the treatment composition in an amount of at least 0.01 g / 1000 g of the treatment composition, such as at least 0.05 g / 1000 g of the treatment composition, and in some cases, not more than 3 g / 1000 g of the processing composition, such as not more than 0.3 g / 1000 g of the processing composition. According to the present invention, the indicator compound may be present in the treatment composition in an amount of from 0.01 g / 1000 g of the treatment composition to 3 g / 1000 g of the treatment composition, such as from 0.05 g / 1000 g of the treatment composition to 0.3 g / 1000 g of the processing composition.

In accordance with the present invention, an indicator compound that changes color in response to a specific external stimulus provides an advantage when using a processing composition in the sense that it can serve, for example, as a visual indication that the substrate has been treated with the composition. For example, a processing composition containing an indicator that changes color when exposed to a metal ion present in a substrate will change color when complexed with metal ions in that substrate; this allows the user to see that the substrate is in contact with the composition. Similar advantages can be realized by applying an alkaline or acid layer to the substrate and contacting the substrate with the composition of the present invention, which changes color when exposed to an alkaline or acidic pH.

If necessary, the processing composition of the present invention may further comprise a nitrogen-containing heterocyclic compound. The nitrogen-containing heterocyclic compound may include cyclic compounds having 1 nitrogen atom, such as pyrroles, and azole compounds having 2 or more nitrogen atoms, such as pyrazoles, imidazoles, triazoles, tetrazoles and pentazoles; 1 nitrogen atom and 1 oxygen atom, such as oxazoles and isoxazoles; or 1 nitrogen atom and 1 sulfur atom, such as thiazoles and isothiazoles. Non-limiting examples of suitable azole compounds include 2,5-dimercapto-1,3,4-thiadiazole (CAS: 1072-71-5), 1H-benzotriazole (CAS: 95-14-7), 1H-1,2,3- triazole (CAS: 288-36-8), 2-amino-5-mercapto-1,3,4-thiadiazole (CAS: 2349-67-9), also called 5-amino-1,3,4-thiadiazole- 2-thiol, and 2-amino-1,3,4-thiadiazole (CAS: 4005-51-0). In some embodiments, for example, the azole compound contains 2,5-dimercapto-1,3,4-thiadiazole. Furthermore, according to the present invention, the nitrogen-containing heterocyclic compound may be in the form of a salt, such as a sodium salt.

The nitrogen-containing heterocyclic compound may be present in the treatment composition at a concentration of at least 0.0005 g per liter of composition, such as at least 0.0008 g per liter of composition, such as at least 0.002 g per liter of composition, and in some cases may be present in the processing composition in an amount of not more than 3 g per liter of composition, such as not more than 0.2 g per liter of composition, such as not more than 0.1 g per liter of composition. According to the present invention, a nitrogen-containing heterocyclic compound may be present in the treatment composition (if any) at a concentration of from 0.0005 g per liter of composition to 3 g per liter of composition, such as from 0.0008 g per liter of composition to 0.2 g per liter of composition, such as from 0.002 g per liter of composition to 0.1 g per liter of composition.

As indicated above, the processing composition of the present invention contains an aqueous medium as a carrier. The aqueous carrier may optionally contain other materials, such as at least one organic solvent. Non-limiting examples of suitable solvents include propylene glycol, ethylene glycol, glycerin, low molecular weight alcohols (i.e., C1-C12 alcohols) and the like. If an organic solvent is present at all, it may be present in the treatment composition in an amount of at least 1 g of solvent per liter of treatment composition, such as at least about 2 g of solvent per liter of treatment composition, and in some cases, may be present in an amount of not more than 40 g of solvent per liter of processing composition, such as not more than 20 g of solvent per liter of processing composition. According to the present invention, if an organic solvent is generally present in the treatment composition, it may be present in an amount of from 1 g of solvent per liter of treatment composition to 40 g of solvent per liter of treatment composition, such as from 2 g of solvent per liter of treatment composition to 20 g of solvent per liter processing composition.

As indicated above, the processing composition of the present invention described above can be prepared by a method that includes combining lithium salt and carbon dioxide in an aqueous carrier medium to form a treatment composition containing lithium in an amount of 5 ppm to 5500 ppm (based on lithium cation) based on the total weight of the processing composition, and carbonate in an amount of from 15 ppm to 25,000 ppm (based on carbonate) based on the total weight of the processing composition. Suitable lithium salts and amounts of lithium in the processing composition are described above. For example, the lithium salt used in the method of forming the processing composition may contain lithium carbonate, lithium hydroxide, or a combination thereof. A method of manufacturing a processing composition of the present invention may include adjusting the pH of the processing composition to a pH of at least 9.5, for example at least 10, for example at least 11, and in some cases, to a pH of not more than 12.5, for example no more than 12, for example, no more than 11.5. According to the present invention, the pH of the processing composition can be adjusted so as to have a pH of from 9.5 to 12.5, for example, from 10 to 12, for example, from 11 to 11.5. The pH of the treatment composition can be measured in accordance with any of the methods described below, and can be adjusted using, for example, any acid and / or base, if necessary, as described above.

According to the present invention, a method of manufacturing a processing composition comprises combining carbon dioxide and lithium salt in an aqueous medium. According to the present invention, carbon dioxide may be supplied to the aqueous carrier medium in the form of a gas, a solid, or a combination thereof. As used herein, the term " fed " when used with respect to carbon dioxide refers to the incorporation of carbon dioxide into the composition using a source other than atmosphere. Carbon dioxide is supplied to the aqueous medium in an amount sufficient to form a treatment composition containing carbonate (calculated on carbonate) in an amount of at least 15 ppm based on the total weight of the treatment composition, such as at least 50 hours / million, such as at least 200 ppm, and in some cases not more than 25,000 ppm, based on the total weight of the processing composition, such as not more than 15,000 ppm, such as not more than 2,400 ppm. / million In some cases, in accordance with the present invention, carbon dioxide may be combined with water in an amount sufficient to form a processing composition containing carbonate (calculated on carbonate), in an amount of from 15 ppm to 25,000 ppm based on the total weight of the processing composition, such as from 50 ppm to 15,000 ppm, such as from 200 ppm to 2400 ppm.

As indicated above, a method of manufacturing a processing composition according to the present invention may also include the addition of a hydroxide, such as group I hydroxides, ammonium hydroxide, or mixtures thereof. The hydroxide source, if present at all, may be present in any quantity, for example, in such an amount that the pH of the processing composition is in the range from 9.5 to 12.5. Non-limiting examples of Group I hydroxides include sodium hydroxide, potassium hydroxide, lithium hydroxide, or mixtures thereof.

As mentioned above, according to the present invention, a system and method for maintaining a treatment bath formed from a treatment composition comprising lithium carbonate are also disclosed. The processing composition may be the processing composition described above, and may be manufactured in accordance with the method described herein above, or may be manufactured by any method known to those skilled in the art. In one example, in accordance with the present invention, a “treatment bath” may refer to a water bath formed from a starting processing composition containing lithium carbonate, for example, as described above, when treating one or more substrates. As used herein, the term “maintaining” a treatment bath formed from a processing composition containing lithium carbonate (regardless of how the lithium carbonate composition was obtained) refers to maintaining certain treatment bath parameters, including lithium and carbonate concentration and pH, in the desired ranges, such as described above for the processing composition of the present invention. This can be achieved, as described in more detail below, by adding one or more materials from an appropriate source to the treatment bath at work and / or outside of work.

According to the present invention, the maintenance system or method may include (i) adding materials to the treatment bath formed from the processing composition that are different from materials used to formulate the processing composition, and / or (ii) adding materials to the processing bath, formed from a processing composition that are the same as those materials used to formulate said processing composition. For example, although a method of maintaining a treatment bath containing a treatment composition may include adding carbon dioxide to the treatment bath, the treatment composition may be formulated using carbonate.

According to the present invention, a maintenance system or method may include adding materials to the treatment bath containing the treatment composition, which are the same as the materials used to formulate the treatment composition. For example, a treatment composition may be formulated using carbon dioxide (as described above), and a method of maintaining a treatment bath containing a treatment composition may include adding carbon dioxide to the treatment bath.

The system or method of the present invention is not intended to simply add more treatment composition to the treatment bath in order to maintain the bath. Rather, as mentioned above, the system and method of the present invention aims to add carbon dioxide and / or lithium salt and / or hydroxide to the treatment bath in an amount sufficient to maintain the pH of the treatment bath from 9.5 to 12.5 , lithium in an amount of from 5 ppm to 5500 ppm (calculated as lithium cation) based on the total weight of the bath for processing, and carbonate in an amount of from 15 ppm to 25,000 ppm ( when calculating for carbonate), based on the total weight of the bath for processing. Adding can be done at work or out of work.

As mentioned above, according to the present invention, a system for maintaining a bathtub for a treatment formed from a treatment composition comprising lithium carbonate is disclosed. According to the present invention, the system may comprise a lithium salt and / or carbon dioxide, optionally a hydroxide or a combination of any of the above. The lithium salt may include one or more of any of the lithium salts described above, such as, for example, lithium carbonate, lithium hydroxide, or a combination thereof. Carbon dioxide may contain carbon dioxide in the form of a gas, a solid, or a combination thereof. The hydroxide may include one or more of any of the hydroxides mentioned above, such as, for example, lithium hydroxide, sodium hydroxide, potassium hydroxide, or a combination thereof. The lithium salts, carbon dioxide and / or hydroxide described above may be included individually or in any combination in the system, and may be added from appropriate sources of the system to the treatment bath formed from the treatment composition to form a treatment bath supporting pH and amount of lithium and carbonate as described above.

As mentioned above, according to the present invention, a method for maintaining a treatment bath formed from a treatment composition comprising lithium carbonate is also disclosed. According to the present invention, the method includes supplying, during and / or after processing the substrate of the bath, at least one of carbon dioxide and lithium salt, and, if necessary, hydroxide in the bath for processing in an amount sufficient to maintain pH. in the bath for processing in the range of 9.5-12.5, lithium in an amount of from 5 ppm to 5500 ppm (calculated on lithium cation) based on the total weight of the bath for processing, and carbonate in an amount of 15 ppm to 25,000 ppm (based on carbonate) based on the total weight of the bath for processing. The lithium salt, carbon dioxide and hydroxide described above can be added to the treatment bath formed from the treatment composition to achieve a treatment bath that maintains the pH and amount of lithium and carbonate as described above in more detail in the context of the treatment composition of the present invention. For example, according to the present invention, the maintenance method may include adding carbon dioxide to the treatment bath formed from the treatment composition in such an amount that the pH of the treatment bath is maintained below 12.5, and / or adding hydroxide to the treatment bath in such an amount so that the pH of the treatment bath is maintained above 9.5. In the examples of the present invention, carbon dioxide can be slowly sparged into the treatment bath or can be added by pouring dry ice into it, piece by piece. According to the present invention, the pH can be periodically or continuously monitored (as described below) and / or a hydroxide can be added to the treatment bath, as discussed above, to maintain a pH of 9.5 to 12.5.

According to the present invention, as described above, after the supply of carbon dioxide and / or lithium salt and / or hydroxide, lithium (calculated as lithium cation) may be present in the processing composition in an amount of at least 5 ppm, such as at least at least 50 ppm, such as at least 150 ppm, such as at least 250 ppm, based on the total weight of the treatment bath, and in some cases may be present in an amount of not more than 5500 hours / million, such as not more than 1200 hours / million, such as not more than 1000 hours / million, such as not more than 500 hours / million, based on the total weight of the bath for processing. In some cases, according to the present invention, after filing carbon dioxide and / or lithium salt in the bath for processing, lithium may be present (calculated as lithium cation) in an amount of from 5 ppm to 5500 ppm based on the total weight bathtubs for processing, such as from 50 to 1200 ppm, such as from 150 to 1000 ppm, such as from 250 to 500 ppm.

According to the present invention, after supplying carbon dioxide and / or a lithium salt and / or hydroxide, carbonate (calculated as carbonate) may be present in the treatment bath in an amount of at least 15 ppm based on the total weight of the treatment bath, such as at least 50 ppm, such as at least 200 ppm, and in some cases may be present in an amount of not more than 25,000 ppm based on the total weight of the treatment bath, such as not more than 15,000 ppm, such as no more than 2,400 ppm In some cases, according to the present invention, after the supply of carbon dioxide and / or a lithium salt and / or hydroxide, carbonate (calculated on carbonate) may be present in the bath for processing in an amount of from 15 ppm to 25,000 ppm calculated on the total weight of the bath for processing, such as from 50 ppm to 15,000 ppm, such as from 200 ppm to 2400 ppm.

In accordance with the present invention, after supplying carbon dioxide and / or a lithium salt and / or hydroxide, the treatment bath may have a pH of at least 9.5, such as at least 10, such as at least 11, and in some cases may have a pH of not more than 12.5, such as not more than 12, such as not more than 11.5. According to the present invention, after supplying carbon dioxide and / or a lithium salt and / or hydroxide, the treatment bath may have a pH of from 9.5 to 12.5, such as from 10 to 12, such as from 11 to 11.5.

According to the present invention, a method of maintaining a treatment bath may further include adjusting the pH of the treatment bath, for example, by adding any acid and / or base as necessary. According to the present invention, the treatment bath can be maintained by incorporating an acidic material, including water-soluble and / or water-dispersible acids, such as nitric acid, sulfuric acid and / or phosphoric acid. According to the present invention, the pH of the treatment bath can be maintained by incorporating base material, including water-soluble and / or water-dispersible bases, such as group I carbonates, group II carbonates, hydroxides, such as sodium hydroxide, potassium hydroxide, lithium hydroxide, hydroxide ammonia, ammonia; amines such as triethylamine, methylethylamine, or mixtures thereof.

The method of maintaining a treatment bath of the present invention may further include monitoring the pH of the treatment bath using a pH meter and probe corresponding to the size of the bath formed from the treatment composition containing lithium carbonate. An example of a suitable pH meter and probe includes, but is not limited to, Accumet AB15 (supplied by Fisher Scientific) and a single junction electrode (Ag / AgCl reference; Fisher Scientific).

The method of maintaining the treatment bath of the present invention may further include monitoring the amount of lithium, lithium carbonate or carbonate in the bath for processing by any method known to those skilled in the art. For example, according to the present invention, a lithium monitoring method may include, for example, using an optical emission spectrometer or an equivalent measuring instrument, and using a standard sample with a predetermined lithium concentration (for example, a standard of known concentration (such as a 500 ppm lithium standard diluted to 5 ppm Li) at a specific wavelength (eg, 670.784 nm) to calculate the concentration of lithium (metal cation) in the treatment bath. The method of maintaining the treatment bath of the present invention may further include monitoring the amount of carbonate in the treatment bath with any by a method known to those skilled in the art, including, for example, using manual titration or an autotitration method.

It has been unexpectedly discovered that carbon dioxide and / or lithium salt, and optionally hydroxide, can be used to maintain a treatment bath formed from a processing composition containing lithium carbonate, such that the pH and concentration of lithium cation and / or concentration of lithium cation and the concentration of carbonate (anion) can be independently changed or controlled, depending on the conditions in the bath, compared with maintaining the bath, for example, using lithium carbonate, in which the pH, concentration of lithium and the concentration of carbonate all change when lithium carbonate is added to the bath (t .e. there is no independent regulation of each such parameter). For example, carbon dioxide and / or a lithium salt, and optionally hydroxide, can be used to maintain a treatment bath formed from a treatment composition containing lithium carbonate, so that the treatment bath has a pH of from 9.5 to 12.5, a concentration lithium from 5 ppm to 5500 ppm (when calculated on lithium cation) based on the total weight of the bath for processing and carbonate concentration from 15 to 25,000 ppm (when calculated on carbonate) calculated on the total the mass of the bath for processing.

As mentioned above, the treatment composition or bath formed from it contains an aqueous medium as a carrier. Accordingly, the composition or bath may be in the form of a solution or dispersion of a lithium salt in a carrier. According to the present invention, the solution or dispersion can be brought into contact with the substrate to be treated with the composition or the bath, by any of a variety of known methods, such as immersion or immersion, spraying, intermittent spraying, immersion followed by spraying, spraying followed by immersion, brush application , or application by roller. According to the invention, the solution or dispersion when applied to a substrate may have a temperature in the range of 40 ° F (5 ° C) to about 160 ° F (71 ° C), such as 60 ° F (16 ° C) to 110 ° F (43 ° C). For example, the process of contacting the substrate with the processing composition can be carried out at room temperature or ambient temperature, such as 23 ° C, unless otherwise indicated. The contact time is often from about 1 second to 2 hours, for example, from 5 minutes to 60 minutes.

According to the present invention, the thickness of the layer formed by the composition for processing, can be, for example, up to 550 nm, for example, from 5 nm to 550 nm, for example, from 10 nm to 400 nm, for example, from 25 nm to 250 nm. The thickness of the layer formed from the processing composition can be determined using several analytical techniques, including, but not limited to, depth profiling with XPS (X-ray photoelectron spectroscopy) or TEM (transmission electron microscopy). As used herein, the term “thickness” as applied to a layer formed by the processing composition of the present invention refers to either (a) a layer formed above the original air / substrate interface, (b) a modified layer formed below the pre-coating / substrate interface , or (c) a combination of (a) and (b) as shown in FIG. 3. Although a modified layer (b) is shown extending to the pre-coating / substrate interface in FIG. 3, an intermediate layer may be present between the modified layer (b) and the pre-coating / substrate interface. Similarly, (c), the combination of (a) and (b) is not limited to a continuous layer and may include multiple layers with intermediate layers between them, and measuring the thickness of the layer (c) may exclude intermediate layers.

Suitable substrates that can be used in the present invention include metal substrates, substrates of metal alloys and / or substrates that have been metallized, such as nickel-plated plastic. According to the present invention, the metal or metal alloy may contain or be steel, aluminum, zinc, nickel and / or magnesium. For example, the steel substrate may be cold rolled steel, hot rolled steel, electroplated galvanized steel, and / or hot galvanized steel. Aluminum alloys of the 1XXX, 2XXX, 3XXX, 4XXX, 5XXX, 6XXX or 7XXX series, as well as clad aluminum alloys, can also be used as a substrate. Aluminum alloys may contain from 0.01 wt.% Copper to 10 wt.% Copper. Machined aluminum alloys 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). Magnesium alloys of the AZ31B, AZ91C, AM60B or EV31A series can also be used as the substrate. The substrate used in the present invention may also contain titanium and / or titanium alloys, zinc and / or zinc alloys and / or nickel and / or nickel alloys. According to the present invention, the substrate may include a part of the vehicle, such as a vehicle body (for example, a door, a body panel, a cargo deck cover, a roof panel, a hood, a roof and / or longitudinal beams, rivets, landing gear components, and / or trim aircraft, but not limited to) and / or the frame of the vehicle. As used herein, the term “vehicle” or its variants includes, but is not limited to, civilian, commercial, and military aircraft and / or land vehicles such as cars, motorcycles, and / or trucks.

According to the present invention, at least a portion of the surface of the substrate can be cleaned and / or deoxidized and / or otherwise pretreated by any conventional means known in the field of cleaning or pretreatment of the metal substrate, before contacting at least a portion of the surface of the substrate with the treatment composition or a treatment bath described above to remove grease, dirt and / or other foreign substances. At least a portion of the surface of the substrate can be cleaned by physical and / or chemical means, such as machining the surface with an abrasive tool and / or cleaning / degreasing the surface with commercially available alkaline or acidic cleaners that are well known to those skilled in the art. Examples of alkaline cleaners suitable for use in the present invention include Chemkleen ™ 166HP, 166M / C, 177, 490MX, 2010LP and Surface Prep 1 (SP1), Ultrax 32, Ultrax 97, Ultrax 29 and Ultrax92D, each of which are commercially available PPG Industries, Inc. (Cleveland, Ohio), and any DFM, RECC 1001, and 88X1002 series cleaning products supplied by PRC-DeSoto International, Silmar, CA), as well as Turco 4215-NCLT and Ridolene (supplied by Henkel Technologies, Madison Heights, MI). Treatment with such cleaning agents is often preceded or followed by a rinse with water, such as tap water, distilled water, or combinations thereof.

As mentioned above, according to the present invention, at least a portion of the cleaned surface of the substrate can be mechanically and / or chemically deoxidized. As used herein, the term “deoxidation” means the removal of an oxide layer located on a surface of a substrate in order to facilitate uniform deposition of a conversion composition or a pretreatment composition, as well as to facilitate the adhesion of such a coating of the composition to the surface of the substrate. Suitable deoxidizing agents are known to those skilled in the art. A typical mechanical deoxidizing agent may be to uniformly provide surface roughness to the substrate, for example using abrasive or cleaning sponges. Typical chemical deoxidants include, for example, acid-based deoxidants such as phosphoric acid, nitric acid, fluoroboric acid, sulfuric acid, chromic acid, hydrofluoric acid and ammonium difluoride, or Amchem 7/17 deoxidants (available from Henkel Technologies, Madison Heights, MI) ), OAKITE DEOXIDIZER LNC (supplied by Chemetall), TURCO DEOXIDIZER 6 (supplied by Henkel), or combinations thereof. Often, the chemical deoxidant contains a carrier, often an aqueous medium, so that the deoxidizer can be in the form of a solution or dispersion in the carrier, in which case the solution or dispersion can be brought into contact with the substrate by any of various known methods, such as immersion or immersion, spraying , intermittent spraying, immersion followed by spraying, spraying followed by immersion, brush application, or roller application. In accordance with the present invention, one skilled in the art will select the temperature range of the solution or dispersion when applied to a metal substrate based on etching rates, for example, at a temperature in the range of 50 ° F to 150 ° F (10 ° C to 66 ° C ), such as from 70 ° F to 130 ° F (from 21 ° C to 54 ° C), such as from 80 ° F to 120 ° F (from 27 ° C to 49 ° C). The contact time can be from 30 seconds to 20 minutes, for example, from 1 minute to 15 minutes, for example, from 90 seconds to 12 minutes, for example, from 3 minutes to 9 minutes.

After the purification and / or deoxidation step (s), the substrate can be washed if necessary with tap water, deionized water and / or an aqueous solution of washing agents to remove any residue. According to the present invention, the wet surface of the substrate can be pretreated by any method known to those skilled in the art of protecting the substrate, for example, anodized or treated with a conversion composition, and / or can be treated with one of the processing compositions described above, or the substrate can be dried before treatment the surface of the substrate, for example, is dried in air, for example, using an air knife, by instantly evaporating water by briefly applying a high temperature to the substrate, such as from 15 ° C to 100 ° C, such as from 20 ° C to 90 ° C or in a heating unit using, for example, infrared heat, for example, for 10 minutes at 70 ° C, or by passing the substrate between the squeeze rollers. According to the present invention, the conversion composition may contain, for example, an element of the lanthanide family, a metal of group IIIB and / or a metal of group IVB, and may further comprise a metal of group IIA, group VB metal, group VIB metal, group VIIB metal, and / or group XII . According to the present invention, an element of the lanthanide family may, for example, include cerium, praseodymium, terbium, or combinations thereof; Group IIA metal may include magnesium; Group IIIB metal may include yttrium, scandium, or combinations thereof; Group IVB metal may include zirconium, titanium, hafnium, or combinations thereof; a metal of group VB may include vanadium; Group VIB metal may include trivalent or hexavalent chromium and / or molybdenum; Group VIIB metal may include manganese; and a Group XII metal may include zinc.

According to the present invention, after the substrate has contacted the treatment composition, the coating composition containing the film-forming resin can be applied to at least a portion of the surface of the substrate that has been in contact with the treatment composition. Any suitable technology can be used to apply such a coating composition to a substrate, including, for example, brushing, dipping, spraying, spraying, and the like. However, in some cases, as described in more detail below, such a coating composition may include an electrodeposition step, in which the electrodepositable composition is deposited on a metal substrate by electrodeposition. In some other cases, as described in more detail below, such a coating composition comprises a powder coating step. In other cases, the coating composition may be a liquid coating composition.

According to the present invention, 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 the horizontal surface of the substrate by removing any diluents or carriers present in the composition or by curing at room temperature or elevated temperature. Conventional film-forming resins that can be used include, but are not limited to, those commonly used in automotive OEM coating compositions, automobile repair coating compositions, industrial coating compositions, architectural coating compositions, strip metal coating compositions, and aerospace coating compositions, inter alia. As used herein, the term “thermosetting” refers to resins that are irreversibly “cured” by curing or crosslinking, where the polymer chains of the polymer components are joined together by covalent bonds. This property is usually associated with the crosslinking reaction of the components of the composition, often caused, for example, by heating or irradiation. Curing or crosslinking reactions can also be carried out under ambient conditions. After curing or crosslinking, the thermosetting resin does not melt when exposed to heat and does not dissolve in solvents. Used in this application, the term "thermoplastic" refers to resins that contain polymer components that are not connected by covalent bonds and, therefore, can undergo a liquid flow when heated and soluble in solvents.

As indicated previously, in accordance with the present invention, an electrodepositable coating composition comprising a water-dispersible film-forming resin containing an ionic salt group can be deposited on a substrate by an electrodeposition step, wherein the electrodepositable coating composition is applied to a metal substrate by electrodeposition. The film-forming polymer containing an ionic salt group may comprise a film-forming polymer containing a cationic salt group for use in a composition for a cationic electrodepositable coating. As used herein, the term “film-forming polymer containing a cationic salt group” refers to polymers that contain at least partially neutralized cationic groups, such as sulfonium groups and ammonium groups, which impart a positive charge. A film-forming polymer containing cationic salt groups may contain active hydrogen functional groups, including, for example, hydroxyl groups, primary or secondary amino groups, and thiol groups. Film-forming polymers containing cationic salt groups that contain active hydrogen functional groups may be referred to as film-forming polymers containing cationic salt groups containing active hydrogen. Examples of polymers that are suitable for use as a film-forming polymer containing cationic salt groups include alkyd polymers, acrylics, polyepoxides, polyamides, polyurethanes, polyureas, polyethers and polyesters, among others, but not limited to. A film-forming polymer containing a cationic salt group may be present in the composition for a cationic electrodepositable coating in an amount of from 40 to 90 wt.%, Such as from 50 to 80 wt.%, Such as from 60 to 75 wt.%, Based on the total the mass of solids of the resin electrodepositable coating composition. As used herein, the term “resin solids” includes a film-forming polymer containing an ionic salt group, a hardener, and any additional water-dispersible, non-pigmented component (s) present in the electrodepositable coating composition.

Alternatively, a film-forming polymer containing an ionic salt group may comprise a film-forming polymer containing an anionic salt group for use in an anionic electrodepositable coating composition. As used herein, the term “film-forming polymer containing an anionic salt group” refers to an anionic polymer containing at least partially neutralized anionic functional groups, such as carboxylic acid and phosphoric acid groups, which impart a negative charge. A film-forming polymer containing an anionic salt group may contain functional groups with active hydrogen. Film-forming polymers containing anionic salt groups that contain active hydrogen functional groups may be referred to as film-forming polymers containing anionic salt groups containing active hydrogen. A film-forming polymer containing an anionic salt group may include base-solubilized film-forming polymers containing a carboxylic acid group, such as a 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 an ester of a fatty acid, unsaturated acid or anhydride and any further unsaturated modifying materials that have further reacted with the polyol. Also suitable are at least partially neutralized copolymers of hydroxyalkyl esters of unsaturated carboxylic acids, unsaturated carboxylic acid and at least one other ethylenically unsaturated monomer. Another suitable anionic electrodepositable resin includes an alkyd-aminoplast carrier, i.e., a carrier containing an alkyd resin and an amino aldehyde resin. Another suitable anionic electrodepositable resin composition comprises mixed esters of a resinous polyol. Other polymers with an acidic functional group, such as phosphated polyepoxide or phosphated acrylic polymers, may also be used. Typical phosphated polyepoxides are disclosed in US Patent Application Publication No. 2009-0045071 in paragraphs [0004] - [0015] and in US Patent Application Ser. No. 13/23093 in [0014] to [0040], cited portions of which are incorporated herein by reference. A film-forming polymer containing an anionic salt group may be present in the composition of the anionic electrodepositable coating in an amount of from 50% to 90%, such as from 55% to 80%, such as from 60% to 75%, based on the total weight of resin solids electrodepositable coating compositions.

The electrodepositable coating composition may further comprise a hardener. The hardener can react with reactive groups, such as active hydrogen groups, a film-forming polymer containing an ionic salt group, to cure the coating composition to form a coating. Non-limiting examples of suitable hardeners are at least partially blocked polyisocyanates, aminoplast resins, and phenoplastic resins such as phenol formaldehyde condensates, including allyl ether derivatives thereof. The hardener may be present in the composition of the cationic electrodepositable coating in an amount of from 10 to 60 wt.%, Such as from 20 to 50 wt.%, Such as from 25 to 40 wt.%, Based on the total weight of solids of the resin of the electrodepositable coating composition. Alternatively, the hardener may be present in the composition of the anionic electrodepositable coating in an amount of from 10 to 50 wt.%, Such as from 20 to 45 wt.%, Such as from 25 to 40 wt.%, Based on the total weight of solids of the resin of the electrodepositable composition coverings.

The electrodepositable coating composition may further comprise other optional ingredients, such as a pigment composition, and, if necessary, various additives, such as fillers, plasticizers, antioxidants, biocides, UV absorbers and stabilizers, sterically hindered amine light stabilizers, antifoam agents, fungicides, dispersants additives, flow control agents, surfactants, wetting agents, or combinations thereof. The electrodepositable coating composition may contain water and / or one or more organic solvents. Water may, for example, be present in an amount of from 40 to 90 wt.%, Such as from 50 to 75 wt.%, Based on the total weight of the electrodepositable coating composition. When used, organic solvents can usually be present in an amount of less than 10 wt.%, Such as less than 5 wt.%, Based on the total weight of the electrodepositable coating composition. The composition for electrodepositable coating, in particular, can be presented in the form of an aqueous dispersion. The total solids content in the electrodepositable coating composition may be from 1 to 50 wt.%, For example, from 5 to 40 wt.%, For example, from 5 to 20 wt.%, Based on the total weight of the electrodepositable coating composition. Used in this application, the term "total solids content" refers to the non-volatile content of the electrodepositable coating composition, that is, materials that will not evaporate when heated to 110 ° C for 15 minutes.

The composition of the cationic electrodepositable coating can be applied to the electrically conductive substrate by placing the composition in contact with the electrically conductive cathode and the electrically conductive anode, the surface on which the coating is applied is the cathode. Alternatively, the anionic electrodepositable coating composition may be deposited on the electrically conductive substrate by contacting the composition with the electrically conductive cathode and the electrically conductive anode, the surface on which the coating is applied is an anode. The adhesive film of the electrodepositable coating composition is deposited in a substantially continuous manner on the cathode or anode, respectively, when sufficient voltage is applied between the electrodes. The applied voltage can vary, and can be, for example, from one volt to several thousand volts, for example, from 50 to 500 volts. The current density is usually 1.0 to 15 amperes per square foot (10.8 to 161.5 amperes per square meter) and tends to decrease rapidly during electrodeposition, indicating the formation of a continuous self-insulating film.

After the cationic or anionic electrodepositable coating composition has been electrodeposited on at least a portion of the electrically conductive substrate, the coated substrate can be heated to a temperature and for a time sufficient to cure the electrodeposited coating on the substrate. For cationic electrodeposition, the coated substrate can be heated to a temperature in the range of 250 to 450 ° F (121.1 to 232.2 ° C), such as 275 to 400 ° F (135 to 204.4 ° C), such as 300 to 360 ° F (149 to 180 ° C). For anionic electrodeposition, the coated substrate can be heated to a temperature in the range of 200 to 450 ° F (93 to 232.2 ° C), such as 275 to 400 ° F (135 to 204.4 ° C), such as 300 to 360 ° F (149 to 180 ° C), such as 200 to 210.2 ° F (93 to 99 ° C). The curing time may depend on the curing temperature, as well as on other variables, for example, the thickness of the electrodepositable coating film, the level and type of catalyst present in the composition, and the like. For example, the curing time may be from 10 minutes to 60 minutes, for example, from 20 to 40 minutes. The thickness of the resulting cured electrodepositable coating can be from 2 to 50 microns.

Alternatively, as mentioned above, according to the present invention, after the substrate has come into contact with the treatment composition, the powder coating composition can then be applied to at least a portion of the surface of the substrate that has come into contact with the treatment composition. As used herein, the term “powder coating composition” refers to a coating composition that is completely free of water and / or solvent. Accordingly, the powder coating composition disclosed herein is not synonymous with water-based and / or solvent-based coating compositions known in the art. According to the present invention, the powder coating composition may contain (a) a film-forming polymer having a reactive functional group; and (b) a hardener that is reactive with said functional group. Examples of powder coating compositions that may be used in the present invention include the ENVIROCRON polyester powder coating composition line (supplied by PPG Industries, Inc.) or a hybrid epoxy polyester powder coating composition. Alternative examples of powder coating compositions that can be used in the present invention include low temperature curable powder coating compositions containing (a) at least one tertiary semicarbazide 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 described in US Pat. No. 7,470,752, owned by PPG Industries, Inc. and incorporated herein by reference); curable powder coating compositions typically containing (a) at least one tertiary semicarbazide 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 described in US patent No. 7,432,333, owned by PPG Industries, Inc. and incorporated herein by reference); and those containing a solid dispersed mixture of a polymer containing a reactive group having a Tg of at least 30 ° C (such as described in US Pat. No. 6,797,387, owned by PPG Industries, Inc. and incorporated herein by reference).

After applying the powder coating composition, the coating is often heated to cure the applied composition. The heating or curing operation is often carried out at a temperature in the range from 150 to 200 ° C., such as from 170 to 190 ° C., for a period of time from 10 to 20 minutes. According to the invention, the thickness of the resulting film is from 50 to 125 microns.

As mentioned above, according to the present invention, the coating composition may be a liquid coating composition. As used herein, the term “liquid coating composition” refers to a coating composition that contains a proportion of water and / or solvent. Accordingly, the liquid coating composition disclosed herein is synonymous with water-based and / or solvent-based coating compositions known in the art. According to the present invention, the liquid coating composition may contain, for example, (a) a film-forming polymer having a reactive functional group; and (b) a hardener that is reactive with said functional group. In other examples, the liquid coating may contain a film-forming polymer that can react with oxygen in air or coalesce into a film with the evaporation of water and / or solvents. These film formation mechanisms may require application, or be accelerated by the use of heat or some type of radiation, such as ultraviolet or infrared radiation. Examples of liquid coating compositions that can be used in the present invention include the SPECTRACRON® solvent-based coating composition line, the AQUACRON® water-based coating composition line, and the UV-cured RAYCRON® coating line (all supplied by PPG Industries, Inc). Suitable film-forming polymers that can be used in the liquid coating composition of the present invention may include (poly) ester, alkyd, (poly) urethane, isocyanurate, (poly) urea, (poly) epoxy, anhydride, acrylic, (poly) ether , (poly) sulfide, (poly) amine, (poly) amide, (poly) vinyl chloride, (poly) olefin, (poly) vinylidene fluoride, (poly) siloxane, or combinations thereof.

According to the present invention, the substrate that has come into contact with the treatment composition can also come into contact with the primer composition and / or the coating composition. The primer coating can be, for example, chromate primers and high-quality finish coatings. In accordance with the present invention, the primer coating may be a conventional chromate-based primer, such as available from PPG Industries, Inc. (product code 44GN072), or a chromium-free primer, such as available from PPG (DESOPRIME CA7502, DESOPRIME CA7521, Deft 02GN083, Deft 02GN084). Alternatively, the primer coating may be a chromate-free primer, such as the coating compositions described in US Ser. No. 10/758,973, entitled "CORROSION RESISTANT COATINGS CONTAINING CARBON", and US Patent Application Ser. No. 10 / 758,972 and 10 / 758,972, both under the name "CORROSION RESISTANT COATINGS", all of which are incorporated herein by reference, and other chromium-free primers known in the art that may meet the requirements of the Ministry’s standard US Defense MIL-PRF-85582 Class N or MIL-PRF-23377 Class N, may also be used in accordance with the present invention.

As mentioned above, the substrate of the present invention may also contain a finishing coating. As used herein, the term “finish coat” refers to a mixture of a binder agent (s), which may be an organic or inorganic polymer, or a mixture of polymers, usually with at least one pigment, and may optionally contain at least one a solvent or mixture of solvents, and may optionally contain at least one hardener. Finishing coating, as a rule, is a coating layer in a single-layer or multilayer coating system, the outer surface of which is exposed to the atmosphere or the environment, and its inner surface is in contact with another coating layer or polymer substrate. Examples of suitable finishes include those that comply with MIL-PRF-85285D, such as those available from PPG (Deft 03W127A and Deft 03GY292). In accordance with the present invention, the finish coating may be an improved performance finish, such as those available from PPG (Defthane® ELT.TM. 99GY001 and 99W009). However, other finishes and finishes with improved characteristics may be used in the present invention, as will be understood by those skilled in the art with reference to this description.

According to the present invention, the metal substrate may also comprise a self-priming finish coating or a reinforced self-priming finish. The term “self-priming topcoat”, also referred to as “directly on a substrate” or “directly on a metal”, refers to a mixture of a binder (s), which may be a polymer or a mixture of polymers on an organic or inorganic basis, usually at least at least one pigment, which may optionally contain at least one solvent or mixture of solvents, and may optionally contain at least one hardener. The term “reinforced self-priming topcoat”, also referred to as “reinforced coating applied directly to a substrate”, refers to a mixture of functionalized fluorinated binding agents, such as fluoroethylene-alkyl-vinyl ether, in whole or in part with other binding agent (s), which may be a polymer or a mixture of polymers on an organic or inorganic basis, usually at least one pigment, may optionally contain at least one solvent or mixture of solvents, and may optionally contain at least one hardener. Examples of self-priming finishes include those that comply with TT-P-2756A. Examples of auto primer coatings include those supplied by PPG (03W169 and 03GY369), and examples of reinforced self-priming coatings include Defthane® ELTTM / ESPT and product code number 97GY121 supplied by PPG. However, other self-priming topcoats and reinforced self-priming topcoats can be used in the coating system of the present invention, as will be appreciated by those skilled in the art with reference to this disclosure.

According to the present invention, a self-priming finish coating and a reinforced self-priming finish coating can be applied directly to the sealed substrate. The self-priming topcoat and the reinforced self-priming topcoat can optionally be applied to an organic or inorganic polymer coating, such as a primer or paintwork. The self-priming finish coating and the reinforced self-priming finish coating are typically a coating layer in a single layer or multi-layer coating system, where the outer surface of the coating is exposed to the atmosphere or the environment, and the inner surface of the coating is usually in contact with the substrate or an optional polymer coating or primer.

According to the present invention, a topcoat, a self-priming topcoat and a reinforced self-priming topcoat can be applied to the sealed substrate in either a wet or “not fully cured” state that dries or cures over time, so that the solvent evaporates and / or occurs chemical reaction. Coatings can dry or cure either naturally or by accelerated methods, such as a UV curing system, to form a film or “cured” paint. Coatings can also be applied in a semi- or fully cured state, such as with an adhesive material.

In addition, dye and, if necessary, various additives, such as surfactants, wetting agents or a 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. Examples of dyes include pigments, dyes and tinting agents, such as those used in the paint industry and / or listed by the Association of manufacturers of dry paints (DCMA), as well as compositions with special effects. In general, the colorant may be present in the coating composition in any amount sufficient to provide the desired visual and / or color effect. The dye may be from 1 to 65 wt.%, For example from 3 to 40 wt.% Or from 5 to 35 wt.% Based on the total weight of the composition.

ASPECTS

Thus, in view of the foregoing, the present application, in particular without limitation, relates to the following aspects 1-24:

1. A composition comprising carbon dioxide and lithium cation in an aqueous medium.

2. The composition of aspect 1, wherein the carbon dioxide comprises a gas, a solid, or combinations thereof.

3. The composition according to any one of aspects 1 or 2, wherein the lithium cation is present in an amount of from 5 ppm to 5500 ppm (based on lithium cation) based on the total weight of the processing composition.

4. The composition according to any one of the preceding aspects, where the pH is from 9.5 to 12.5.

5. The composition according to any one of the preceding aspects, further comprising hydroxide.

6. The composition according to any one of the preceding aspects, in which the carbonate is present in an amount of from 15 to 25,000 ppm (based on carbonate) based on the total weight of the processing composition.

7. A method of manufacturing a processing composition, comprising combining a lithium cation and carbon dioxide in an aqueous medium to form a processing composition in situ, wherein the processing composition contains lithium in an amount of from 5 ppm to 5500 ppm (based on lithium cation ) based on the total weight of the processing composition and carbonate in an amount of from 15 ppm to 25,000 ppm (when calculated on carbonate) based on the total weight of the processing composition.

8. A method of manufacturing a processing composition according to aspect 7, in which the lithium cation is present in the form of lithium carbonate, lithium hydroxide, or a combination thereof.

9. A method of manufacturing a processing composition according to any one of aspects 7 or 8, wherein the carbon dioxide is supplied to the aqueous medium in the form of a gas, a solid, or a combination thereof.

10. A method of manufacturing a processing composition according to any one of aspects 7-9, comprising adding hydroxide to the aqueous medium.

11. A method of manufacturing a processing composition according to aspect 10, wherein the hydroxide comprises lithium hydroxide, sodium hydroxide, potassium hydroxide, or a combination thereof.

12. A method of manufacturing a processing composition according to any one of aspects 7-11, comprising adjusting the pH of the processing composition to a value of from 9.5 to 12.5.

13. The processing composition obtained in accordance with the method according to any one of aspects 7-12.

14. A method of maintaining a bath for processing formed from a processing composition containing lithium carbonate, the method comprising supplying, during and / or after processing the substrate of said bath, at least one of carbon dioxide and lithium salt in the bath in an amount sufficient to maintain pH baths at a level of from 9.5 to 12.5, lithium in an amount of from 5 ppm to 5500 ppm (when calculated on a lithium cation) based on the total weight of the bath for processing, and carbonate in an amount of 15 hours ./mln up to 25,000 ppm (calculated on carbonate) based on the total weight of the bath for processing.

15. The method of maintaining a treatment bath of aspect 14, wherein the lithium salt comprises lithium carbonate, lithium hydroxide, or a combination thereof.

16. A method of maintaining a treatment bath according to any one of aspects 14 or 15, wherein the carbon dioxide is supplied to the bath in the form of a gas, a solid, or a combination thereof.

17. A method of maintaining a bath for processing according to any one of aspects 14 to 16, comprising supplying hydroxide to the bath.

18. The method of maintaining the treatment bath of aspect 17, wherein the hydroxide comprises lithium hydroxide, sodium hydroxide, potassium hydroxide, or a combination thereof.

19. A method of maintaining a treatment bath according to any one of aspects 14-18, further comprising monitoring the pH of the treatment bath, the amount of carbonate in the treatment bath, the amount of lithium in the treatment bath, or combinations thereof.

20. The substrate processed by the processing composition according to any one of aspects 1-6 or 13, or by using a treatment bath maintained in accordance with the method according to any one of aspects 14-19.

21. A system for maintaining a treatment bath formed from a processing composition comprising lithium carbonate, the system comprising:

- source of lithium salt; and / or

- carbon dioxide source; and

- if necessary, a source of hydroxide.

22. The system for maintaining a bathtub for processing according to aspect 21, wherein the lithium salt source includes lithium carbonate, lithium hydroxide, or a combination thereof.

23. A system for maintaining a treatment bath according to any one of aspects 21 or 22, wherein the carbon dioxide source comprises carbon dioxide in the form of a gas, a solid, or a combination thereof.

24. A system for maintaining a treatment bath according to any one of aspects 21-23, comprising a hydroxide source including lithium hydroxide, sodium hydroxide, potassium hydroxide, or a combination thereof.

While the specific features of the present invention have been described above for purposes of illustration, it will be apparent to those skilled in the art that numerous variations of the details of the treatment composition and the bath formed from it and the methods for preparing and maintaining it disclosed herein may be made without departing from the scope of the attached claims.

The invention is illustrated by the following examples, which should not be construed as limiting the invention to their details. All parts and percentages in the examples, as well as throughout the description are given by weight, unless otherwise indicated.

Examples

Table 2 - Materials

Lithium carbonate, 98% Alfa aesar Lithium hydroxide monohydrate, 98% minimum Alfa aesar Carbon dioxide gas Air gas Sodium hydroxide, granules, 98% Alfa aesar Sodium Phosphate Dodecahydrate, 97% Alfa aesar Polyvinylpyrrolidone (PVP), 8000 m.m. Alfa aesar Allantoin, 98% Alfa aesar 2,5-dimercapto-1,3,4-thiadiazole, 98% Acros organics Carbowet GA100, 100% Air products Cerium nitrate solution (65.37% Ce (NO ₃ ) ₃ ∙ 6H ₂ O) ProChem Inc. Yttrium nitrate solution (72.45% Y (NO ₃ ) ₃ ∙ 6H ₂ O) ProChem Inc. Cerium chloride solution (32.2% as CeO ₂ *) ProChem Inc. Hydrogen Peroxide Solution (30% H ₂ O ₂ ) Alfa aesar

* According to Certificate of Analysis from the supplier

Table 3 - The composition of the cleaner / deoxidant (Example A)

Mass (g) Sodium hydroxide, granules, 98% 0.016 Sodium Phosphate Dodecahydrate, 97% 0,063 Polyvinylpyrrolidone (PVP), 8000 m.m. 0.002 Allantoin, 98% 0.003 2,5-dimercapto-1,3,4-thiadiazole (DMTD), 98% 0,100 Carbowet GA100 0.410 Deionized water 98.7

The ingredients and their relative amounts used to prepare the cleaner / deoxidizing composition of Example A are shown in Table 3. Sodium hydroxide and sodium phosphate were completely dissolved in deionized water with moderate mechanical stirring using a mixing plate (VWR, 7x7 CER HOT / STIR) . Then, when sodium hydroxide and sodium phosphate were completely dissolved, PVP was mixed until dissolved, then allantoin was added and mixed until dissolved, then DMTD was added and mixed until dissolved. After complete dissolution, DMTD was mixed with Carbowet GA100 with moderate stirring with a mechanical stirrer, as described above.

Table 4 - Conversion composition (Example B)

Mass (g) Yttrium Nitrate Solution 12.48 Cerium nitrate solution 10.40 Cerium chloride solution 0.04 Hydrogen peroxide solution 1,04 Deionized water 1953

The ingredients used to prepare the solution of the conversion coating composition from Example B and their amounts are shown in Table 4. Solutions of cerium nitrate, yttrium nitrate and cerium chloride were weighed in separate dishes. Then, using 500 g of deionized water, the solutions were transferred to a vessel containing 1000 g of deionized water with moderate stirring. The remaining 453 g of water was added, and the solution was stirred for 10 minutes to ensure uniformity before the addition of hydrogen peroxide. The final solution was mixed for at least 30 minutes before use.

Table 5 - Sealing compositions (Examples C-O)

LiCO ₃ (98% purity) (g) LiOH (98% purity) (g) Li (mol) CO ₂ 5% LiOH solution (g) Deionized Water (g) pH Etc. C 3.06 --- 0,081 --- --- 1996.94 11.52 Etc. D --- 1.99 0,081 --- --- 1998.01 12.69 Etc. E --- --- --- Bubbling --- --- 11.42 Etc. F --- --- --- Bubbling --- --- 10.54 Etc. G --- --- --- Bubbling --- --- 9.47 Etc. H --- --- --- --- 15.3 --- 10.47 Etc. I --- --- --- --- 15,5 --- 11.48 Etc. J --- --- --- --- 23,2 --- 12.47 Etc. K 3.06 --- 0,081 --- --- 1996.94 11.14 Etc. L --- 1.99 0,081 --- --- 1998.01 12.17 Etc. M --- --- --- Bubbling --- --- 11.37 Etc. N --- --- --- Bubbling --- --- 9.50 Etc. O --- --- --- --- 15,54 --- 11.37

In preparing the sealant compositions, the pH for each of Examples CJ was measured using a pH meter (Accumet AB15, Fisher Scientific) and a single junction electrode (Ag / AgCl reference; Fisher Scientific), and the pH for each of Examples K-O was measured using pH- meter (Mettler Toledo, Seven2Go, model S2) and an electrode with a double open junction (Mettler Toledo, Xerolyt® polymer standard).

The sealant composition of Example C and Example K was prepared using the ingredients shown in Table 5 by dissolving lithium carbonate in deionized water with moderate stirring using a stirring plate as described above (VWR, 7x7 CER HOT / STIR). The final pH value in Example C was 11.52. Example C was used to process panels in Comparative Example 1 (described below). The final pH value in Example K was 11.14. Example K was used for processing panels in Comparative Example 9 (described below).

The sealant composition of Example D and Example L was prepared using the ingredients shown in Table 5 by dissolving lithium hydroxide in deionized water with moderate stirring using a stirring plate as described above. In Example D, the final pH was 12.69. Example D was used for processing panels in Comparative Example 2 (described below). In Example L, the final pH was 12.17. Example L was used for processing panels in Comparative Example 10 (described below).

After using a bath containing the composition of Example D for processing panels according to Comparative Example 2, a sealant composition of Example E was prepared by sparging carbon dioxide gas in a bath containing the composition of Example D until the final pH was 11.42. See Figure 1 and Table 5. Example E was used to process the panels in Example 3 (described below).

After using the bath containing the composition of Example E to process the panels in accordance with Example 3, the sealing composition of Example F was prepared by sparging an additional amount of carbon dioxide gas in the composition of Example E until a final pH of 10.54 was obtained. See Figure 1 and Table 5. Example F was used to process the panels in Example 4 (described below).

After using the bath containing the composition of Example F to treat the panels of Example 4, the sealant composition of Example G was prepared by sparging an additional amount of carbon dioxide gas in the composition of Example F to obtain a final pH of 9.47. See Figure 1 and Table 5. Example G was used to process the panels in Example 5 (described below).

After using a bath containing the composition of Example G to process the panels according to Example 5, a sealant composition of Example H was prepared by adding a 5% lithium hydroxide solution to the composition of Example G until a final pH of 10.47 was reached. See Figure 1 and Table 5. Example H was used to process the panels in Example 6 (described below).

After using a bath containing the composition of Example H according to Example 6, a sealant composition of Example I was prepared by adding a 5% lithium hydroxide solution to the composition of Example H until a final pH of 11.48 was obtained. See Figure 1 and Table 5. Example I was used to process the panels in Example 7 (described below).

After using a bath containing the composition of Example I in accordance with Example 7, the sealing composition of Example J was prepared by adding a 5% lithium hydroxide solution to the composition of Example I to obtain a final pH of 12.47. See Figure 1 and Table 5. Example J was used to process the panels in Example 8 (described below).

After using the bath containing the composition of Example L to process the panels according to Comparative Example 10, the sealant composition of Example M was prepared by sparging carbon dioxide gas in the bath containing the composition of Example L to a final pH of 11.37. See Figure 2 and Table 5. Example M was used to process the panels in Example 11 (described below).

After using the bath containing the composition of Example M to process the panels according to Example 11, the sealing composition of Example N was prepared by sparging an additional amount of carbon dioxide gas in the composition of Example M until a final pH of 9.5 was obtained. See Figure 2 and Table 5. Example N was used to process the panels in Example 12 (described below).

After using a bath containing the composition of Example N according to Example 12, the sealant composition of Example O was prepared by adding a 5% lithium hydroxide solution to the composition of Example N until a final pH of 11.37 was obtained. See Figure 2 and Table 5. Example O was used to process the panels in Example 13 (described below).

Panel Preparation

Comparative Example 1

A bare 2024T3 aluminum substrate (obtained from Priority Metals, Orange County, CA) measuring 3 ”x 5” x 0.032 ”was manually wiped with methyl ethyl ketone and a disposable cloth, and air-dried before chemical cleaning. The panel was immersed in the cleaner-deoxidizer composition from Example A for 3.5 minutes at ambient temperature with periodic stirring. The panel was then subjected to two washes by immersion in deionized water for two minutes for each washing, both at ambient temperature with periodic stirring. After a second wash, the panel was cascaded with deionized water for 10 seconds. The panel was then immersed in the conversion composition from Example B for 5 minutes at ambient temperature without stirring. The panel was then washed by immersion in deionized water for 2 minutes at ambient temperature with periodic stirring, followed by a 10-second cascade washing in deionized water. The panel was then immersed in the sealing composition from Example C for 2 minutes at ambient temperature with periodic stirring. The panel was air-dried at ambient conditions overnight before a corrosion test, as described below.

Reference Example 2

A bare 2024T3 aluminum substrate (obtained from Priority Metals, Orange County, CA) measuring 3 ”x 5” x 0.032 ”was manually wiped with methyl ethyl ketone and a disposable cloth, and air-dried before chemical cleaning. The panel was immersed in the cleaner-deoxidizer composition from Example A for 3.5 minutes at ambient temperature with periodic stirring. The panel was then subjected to two washes by immersion in deionized water for two minutes for each washing, both at ambient temperature with periodic stirring. After a second wash, the panel was cascaded with deionized water for 10 seconds. The panel was then immersed in the conversion composition from Example B for 5 minutes at ambient temperature and without stirring. The panel was then washed by immersion in deionized water for 2 minutes at ambient temperature with periodic stirring, followed by a 10-second cascade washing in deionized water. The panel was then immersed in the sealing composition from Example D for 2 minutes at ambient temperature with periodic stirring. The panel was air-dried at ambient conditions overnight before corrosion tests, as described below.

Example 3

After the panels of comparative Example 2 were treated with the sealing solution from Example D, the pH of the bath was adjusted by sparging carbon dioxide gas in the bath until the pH reached 11.42 (i.e., to obtain Example E as described above ) See Figure 1.

Then, an additional bare 2024T3 aluminum substrate (obtained from Priority Metals, Orange County, CA) measuring 3 ”x 5” x 0.032 ”was manually wiped with methyl ethyl ketone and a disposable cloth, and air-dried before chemical cleaning. The panel was immersed in the cleaner-deoxidizer composition from Example A for 3.5 minutes at ambient temperature with periodic stirring. The panel was then subjected to two washes by immersion in deionized water for two minutes for each washing, both at ambient temperature with periodic stirring. After a second wash, the panel was cascaded with deionized water for 10 seconds. The panel was then immersed in the conversion composition from Example B for 5 minutes at ambient temperature and without stirring. The panel was then washed by immersion in deionized water for 2 minutes at ambient temperature with periodic stirring, followed by a 10-second cascade washing in deionized water. Then the panel was immersed in the sealing composition from Example E for 2 minutes at ambient temperature with periodic stirring. The panel was air-dried at ambient conditions overnight before corrosion tests, as described below.

Example 4

After the panels were treated with the sealing solution from Example E, the pH of the bath was adjusted by bubbling carbon dioxide gas in the bath until the pH reached 10.54 (i.e., to obtain Example F as described above). See Figure 1.

Then, an additional bare 2024T3 aluminum substrate (obtained from Priority Metals, Orange County, CA) measuring 3 ”x 5” x 0.032 ”was manually wiped with methyl ethyl ketone and a disposable cloth, and air-dried before chemical cleaning. The panel was immersed in the cleaner-deoxidizer composition from Example A for 3.5 minutes at ambient temperature with periodic stirring. The panel was then subjected to two washes by immersion in deionized water for two minutes for each washing, both at ambient temperature with periodic stirring. After a second wash, the panel was cascaded with deionized water for 10 seconds. The panel was then immersed in the conversion composition from Example B for 5 minutes at ambient temperature and without stirring. The panel was then washed by immersion in deionized water for 2 minutes at ambient temperature with periodic stirring, followed by a 10-second cascade washing in deionized water. The panel was then immersed in the sealing composition of Example F for 2 minutes at ambient temperature with periodic stirring. The panel was air-dried at ambient conditions overnight before a corrosion test, as described below.

Example 5

After the panels were treated with the sealing solution from Example E, the pH of the bath was adjusted by bubbling gaseous carbon dioxide in the bath until the pH reached 9.47 (i.e., to obtain Example G as described above). See Figure 1.

Then, an additional bare 2024T3 aluminum substrate (obtained from Priority Metals, Orange County, CA) measuring 3 ”x 5” x 0.032 ”was manually wiped with methyl ethyl ketone and a disposable cloth, and air-dried before chemical cleaning. The panel was immersed in the cleaner-deoxidizer composition from Example A for 3.5 minutes at ambient temperature with periodic stirring. The panel was then subjected to two washes by immersion in deionized water for two minutes for each washing, both at ambient temperature with periodic stirring. After a second wash, the panel was cascaded with deionized water for 10 seconds. The panel was then immersed in the conversion composition from Example B for 5 minutes at ambient temperature and without stirring. The panel was then washed by immersion in deionized water for 2 minutes at ambient temperature with periodic stirring, followed by a 10-second cascade washing in deionized water. The panel was then immersed in the sealing composition from Example G for 2 minutes at ambient temperature with periodic stirring. The panel was air-dried at ambient conditions overnight before corrosion tests, as described below.

Example 6

After the panels were treated with the sealing solution from Example G, the pH of the bath was adjusted using a lithium hydroxide solution as described above (that is, to obtain Example H as described above). See Figure 1.

Then, an additional bare 2024T3 aluminum substrate (obtained from Priority Metals, Orange County, CA) measuring 3 ”x 5” x 0.032 ”was manually wiped with methyl ethyl ketone and a disposable cloth, and air-dried before chemical cleaning. The panel was immersed in the cleaner-deoxidizer composition from Example A for 3.5 minutes at ambient temperature with periodic stirring. The panel was then subjected to two washes by immersion in deionized water for two minutes for each washing, both at ambient temperature with periodic stirring. After a second wash, the panel was cascaded with deionized water for 10 seconds. The panel was then immersed in the conversion composition from Example B for 5 minutes at ambient temperature and without stirring. The panel was then washed by immersion in deionized water for 2 minutes at ambient temperature with periodic stirring, followed by a 10-second cascade washing in deionized water. The panel was then immersed in the sealing composition from Example H for 2 minutes at ambient temperature with periodic stirring. The panel was air-dried at ambient conditions overnight before corrosion tests, as described below.

Example 7

After the panels were treated with the sealing solution from Example H, the pH of the bath was adjusted using a lithium hydroxide solution as described above (that is, to obtain Example I as described above). See Figure 1.

Then, an additional bare 2024T3 aluminum substrate (obtained from Priority Metals, Orange County, CA) measuring 3 ”x 5” x 0.032 ”was manually wiped with methyl ethyl ketone and a disposable cloth, and air-dried before chemical cleaning. The panel was immersed in the cleaner-deoxidizer composition from Example A for 3.5 minutes at ambient temperature with periodic stirring. The panel was then subjected to two washes by immersion in deionized water for two minutes for each washing, both at ambient temperature with periodic stirring. After a second wash, the panel was cascaded with deionized water for 10 seconds. The panel was then immersed in the conversion composition from Example B for 5 minutes at ambient temperature and without stirring. The panel was then washed by immersion in deionized water for 2 minutes at ambient temperature with periodic stirring, followed by a 10-second cascade washing in deionized water. The panel was then immersed in the sealing composition from Example I for 2 minutes at ambient temperature with periodic stirring. The panel was air-dried at ambient conditions overnight before a corrosion test, as described below.

Example 8

After the panels were treated with the sealing solution from Example I, the pH of the bath was adjusted using a lithium hydroxide solution as described above (that is, to obtain Example I as described above). See Figure 1.

Then, an additional bare 2024T3 aluminum substrate (obtained from Priority Metals, Orange County, CA) measuring 3 ”x 5” x 0.032 ”was manually wiped with methyl ethyl ketone and a disposable cloth, and air-dried before chemical cleaning. The panel was immersed in the cleaner-deoxidizer composition from Example A for 3.5 minutes at ambient temperature with periodic stirring. The panel was then subjected to two washes by immersion in deionized water for two minutes for each washing, both at ambient temperature with periodic stirring. After a second wash, the panel was cascaded with deionized water for 10 seconds. The panel was then immersed in the conversion composition from Example B for 5 minutes at ambient temperature and without stirring. The panel was then washed by immersion in deionized water for 2 minutes at ambient temperature with periodic stirring, followed by a 10-second cascade washing in deionized water. The panel was then immersed in the sealing composition from Example J for 2 minutes at ambient temperature with periodic stirring. The panel was air-dried at ambient conditions overnight before corrosion tests, as described below.

Comparative Example 9

A bare 2024T3 aluminum substrate (obtained from Priority Metals, Orange County, CA) measuring 3 ”x 5” x 0.032 ”was manually wiped with methyl ethyl ketone and a disposable cloth, and air-dried before chemical cleaning. The panel was immersed in the cleaner-deoxidizer composition from Example A for 3.5 minutes at ambient temperature with periodic stirring. The panel was then subjected to two washes by immersion in deionized water for two minutes for each washing, both at ambient temperature with periodic stirring. After a second wash, the panel was cascaded with deionized water for 10 seconds. The panel was then immersed in the conversion composition from Example B for 5 minutes at ambient temperature and without stirring. The panel was then washed by immersion in deionized water for 2 minutes at ambient temperature with periodic stirring, followed by a 10-second cascade washing in deionized water. Then the panel was immersed in the sealing composition from Example K for 2 minutes at ambient temperature with periodic stirring. The panel was air-dried at ambient conditions overnight before a corrosion test, as described below.

Comparative Example 10

A bare 2024T3 aluminum substrate (obtained from Priority Metals, Orange County, CA) measuring 3 ”x 5” x 0.032 ”was manually wiped with methyl ethyl ketone and a disposable cloth, and air-dried before chemical cleaning. The panel was immersed in the cleaner-deoxidizer composition from Example A for 3.5 minutes at ambient temperature with periodic stirring. The panel was then subjected to two washes by immersion in deionized water for two minutes for each washing, both at ambient temperature with periodic stirring. After a second wash, the panel was cascaded with deionized water for 10 seconds. The panel was then immersed in the conversion composition from Example B for 5 minutes at ambient temperature and without stirring. The panel was then washed by immersion in deionized water for 2 minutes at ambient temperature with periodic stirring, followed by a 10-second cascade washing in deionized water. The panel was then immersed in the sealing composition from Example L for 2 minutes at ambient temperature with periodic stirring. The panel was air-dried at ambient conditions overnight before a corrosion test, as described below.

Example 11

After the panels of comparative Example 10 were processed using the sealing solution from Example L, the pH of the bath was adjusted by bubbling carbon dioxide gas in the bath until the pH reached 11.37 (i.e., to obtain Example M, as described above). See Figure 2.

Then, an additional bare 2024T3 aluminum substrate (obtained from Priority Metals, Orange County, CA) measuring 3 ”x 5” x 0.032 ”was manually wiped with methyl ethyl ketone and a disposable cloth, and air-dried before chemical cleaning. The panel was immersed in the cleaner-deoxidizer composition from Example A for 3.5 minutes at ambient temperature with periodic stirring. The panel was then subjected to two washes by immersion in deionized water for two minutes for each washing, both at ambient temperature with periodic stirring. After a second wash, the panel was cascaded with deionized water for 10 seconds. The panel was then immersed in the conversion composition from Example B for 5 minutes at ambient temperature and without stirring. The panel was then washed by immersion in deionized water for 2 minutes at ambient temperature with periodic stirring, followed by a 10-second cascade washing in deionized water. The panel was then immersed in the sealing composition from Example M for 2 minutes at ambient temperature with periodic stirring. The panel was air-dried at ambient conditions overnight before corrosion tests, as described below.

Example 12

After the panels were treated with the sealing solution from Example M, the pH of the bath was adjusted by bubbling carbon dioxide gas in the bath until the pH reached 9.50 (i.e., to obtain Example N, as described above). See Figure 2.

Then, an additional bare 2024T3 aluminum substrate (obtained from Priority Metals, Orange County, CA) measuring 3 ”x 5” x 0.032 ”was manually wiped with methyl ethyl ketone and a disposable cloth, and air-dried before chemical cleaning. The panel was immersed in the cleaner-deoxidizer composition from Example A for 3.5 minutes at ambient temperature with periodic stirring. The panel was then subjected to two washes by immersion in deionized water for two minutes for each washing, both at ambient temperature with periodic stirring. After a second wash, the panel was cascaded with deionized water for 10 seconds. The panel was then immersed in the conversion composition from Example B for 5 minutes at ambient temperature and without stirring. The panel was then washed by immersion in deionized water for 2 minutes at ambient temperature with periodic stirring, followed by a 10-second cascade washing in deionized water. The panel was then immersed in the sealing composition from Example N for 2 minutes at ambient temperature with periodic stirring. The panel was air-dried at ambient conditions overnight before corrosion tests, as described below.

Example 13

After the panels were treated in the sealing solution from Example N, the pH of the bath was adjusted using a lithium hydroxide solution as described above (i.e., to obtain Example O as described above). See Figure 2.

Then, an additional bare 2024T3 aluminum substrate (obtained from Priority Metals, Orange County, CA) measuring 3 ”x 5” x 0.032 ”was manually wiped with methyl ethyl ketone and a disposable cloth, and air-dried before chemical cleaning. The panel was immersed in the cleaner-deoxidizer composition from Example A for 3.5 minutes at ambient temperature with periodic stirring. The panel was then subjected to two washes by immersion in deionized water for two minutes for each washing, both at ambient temperature with periodic stirring. After a second wash, the panel was cascaded with deionized water for 10 seconds. The panel was then immersed in the conversion composition from Example B for 5 minutes at ambient temperature and without stirring. The panel was then washed by immersion in deionized water for 2 minutes at ambient temperature with periodic stirring, followed by a 10-second cascade washing in deionized water. The panel was then immersed in the sealing composition from Example O for 2 minutes at ambient temperature with periodic stirring. The panel was dried in ambient air overnight before a corrosion test as described below.

Corrosion tests

The panels of Examples 1-8 were placed for 7 days in a neutral salt spray chamber operating in accordance with ASTM B117. Corrosion characteristics were evaluated by counting the number of corrosion foci visible to the naked eye on the panels after a 7-day exposure. Corrosion centers that existed prior to testing, on the edge or as a result of scratches, were excluded from the calculation. Corrosion data are shown in Table 6.

The baths of Examples 9-13 were evaluated for lithium carbonate using an autotitration technique (Metrohm 799 GPT Titrino, Software by Tiamo 2,3). % Li ₂ CO ₃ and% CO _{3 were} calculated using the following formulas:

% Li ₂ CO ₃ = [(volume at EP3-volume at EP2) × M.m. Li ₂ CO ₃ × HCl conc. × 100] / (SW × 1000) and

% CO ₃ = [(volume at EP3 - volume at EP2) × M.m. CO ₃ × HCl conc. × 100] / (SW × 1000),

where EP2 is the second endpoint and EP3 is the third endpoint. The concentration of HCl (N) was 0.1012.

These values were used to calculate the amount of carbonate in baths containing the sealant compositions of Examples 9-13, as shown in Table 6.

Table 6. Results of corrosion tests and analysis of carbonate.

Example pH Pockets of corrosion Sample weight (g) HCl (ml) EP2 * HCl (ml) EP3 ** % Li ₂ CO ₃ % CO ₃ Wednesday CO _{3 (%)} Wednesday CO ₃ (parts /
million) Example 1 (Comparative) 11.52 5 --- --- --- --- --- --- --- Example 2 (Comparative) 12.69 100+ --- --- --- --- --- --- --- Example 3 11.42 6 --- --- --- --- --- --- --- Example 4 10.54 10 --- --- --- --- --- --- --- Example 5 9.47 eighteen --- --- --- --- --- --- --- Example 6 10.47 14 --- --- --- --- --- --- --- Example 7 11.48 3 --- --- --- --- --- --- --- Example 8 12.47 39 --- --- --- --- --- --- --- Example 9
(Comparative) 11.14 --- 10,0781
10.0877 2,0809
2,0735 4,1378
4.1618 0.153
0.155 0.124
0,126 0.125 1248 Example 10
(Comparative) 12.17 --- 10,1993
10.3639 4,0802
4.1290 4,1572
4,2158 0.006
0.006 0.005
0.005 0.005 48 Example 11 11.37 --- 10.1814
10.3984 2,2263
2,2655 4,1518
4,2272 0.141
0.141 0.115
0.115 0.115 1147 Example 12 9.50 --- 10.0817
10.8563 0.8203
0.8730 4.0719
4.3789 0.241
0.241 0.196
0.196 0.196 1960 Example 13 11.37 --- 10.4032
10.3221 3.6583
3,5725 7.0788
6.9857 0.246
0.247 0,200
0.201 0,200 2002

Comparative Examples 1 and 9 illustrate treatment baths containing a composition made of lithium carbonate. These Examples illustrate the pH of such a treatment bath containing a composition made of lithium carbonate, and Comparative Example 9 also demonstrated the amount of lithium carbonate and lithium carbonate in the treatment bath. The pH of the bath for the treatment from Comparative Example 1 was 11.52, and on the treated panel after exposure to salt fog there were 5 foci of corrosion. The treatment bath of Comparative Example 9 had a pH of 11.14 and contained 0.154% lithium carbonate and 1248 ppm carbonate.

Comparative examples 2 and 10 illustrate a treatment bath containing a composition made of lithium hydroxide. In particular, the amount of lithium in Example D (used to obtain Comparative Example 2) was the same as the amount of lithium in Example C (used to obtain Comparative Example 1) (0.081 mol of lithium). The pH of the bath for the treatment from Comparative Example 2 was 12.69, and on the treated panel after exposure to salt fog there were more than 100 foci of corrosion. The treatment bath of Comparative Example 10 had a pH of 12.17 and contained only 48 ppm carbonate. Not wishing to be bound by theory, it is assumed that the carbonate present in the treatment bath of Comparative Example 10 is the result of the conversion of CO ₂ to CO ₃ ^- . These data show that lithium, in the absence of a sufficient amount of carbonate, does not provide corrosion protection for the metal substrate treated in the treatment bath.

Example 3 demonstrated that by sparging CO ₂ in a treatment bath, the pH can be reduced to a range comparable to Comparative Example 1, while at the same time reducing the number of corrosion centers on the treated panel to 6. As demonstrated in Example 11, CO ₂ can also be used to form lithium carbonate in a bath in which prior to the addition of CO ₂ there was only a trace amount of lithium carbonate.

Examples 4, 5, and 12 also demonstrated that sparging additional amounts of CO ₂ into the treatment bath lowers the pH, but these Examples show a tendency to increase the number of corrosion spots on the treated panels after exposure to salt fog while lowering the pH of the treatment bath (i.e. the panels processed in Examples 4 and 5 had 10 and 18 corrosion centers at pH 10.54 and 9.47, respectively), compared with Comparative Example 1, where the pH value was 11.52 and 5 corrosion centers on the treated panel, and compared with Example 3, where there was a pH value of 11.42 and 6 pockets of corrosion on the treated panel. As shown in Example 12, in the bath for processing was 1960 ppm of carbonate. These data show that in a bath containing lithium carbonate, pH is critical to corrosion performance.

Examples 6, 7 and 13 demonstrated that the addition of LiOH to increase the pH to 10.47 and 11.48, respectively, led to an improvement in corrosion performance, since the panels processed in Example 6 had 14 foci of corrosion, while the panels processed in Example 7, had 3 pockets of corrosion.

Example 8 demonstrated that increasing the pH to 12.5 worsened the corrosion performance, despite the fact that the carbonate level was sufficient, with a treated panel having 39 foci of corrosion, an improvement over comparative Example 2 in which there was no lithium carbonate, where more than 100 pockets of corrosion were noted and lithium carbonate was not added to the bath.

The examples demonstrate the interaction of pH, lithium concentration and carbonate concentration with respect to corrosion resistance.

Claims (16)

1. A method of obtaining a processing composition for forming a protective coating on a substrate containing lithium carbonate, comprising the reaction of a lithium cation and a source of carbon dioxide in an aqueous medium to obtain a processing composition, wherein said processing composition contains lithium cation in an amount of from 5 ppm to 5500 ppm, when calculated on lithium cation, calculated on the total weight of the processing composition, and carbonate anion in an amount of 15 ppm to 25,000 ppm, calculated on the carbonate anion, calculated on the total weight of the processing composition . 2. The method according to claim 1, in which the pH of the processing composition is from 9.5 to 12.5. 3. The method according to claim 1, which further comprises adding an acid other than carbon dioxide to the treatment composition. 4. The method according to claim 1, in which the lithium cation is used in the form of a salt representing lithium carbonate, lithium hydroxide, or a combination thereof. 5. The method according to claim 1, which further includes adding a source of hydroxide to the aqueous medium. 6. The method according to claim 5, in which the source of the hydroxide is lithium hydroxide, sodium hydroxide, potassium hydroxide, or a combination thereof. 7. The method according to claim 1, wherein the carbon dioxide source is a gas, a solid, or a combination thereof. 8. The substrate treated with the composition containing lithium carbonate to form a protective coating, and which is obtained by the method according to claim 1. 9. A method of preparing a bath for forming a protective coating on a substrate containing a processing composition containing lithium carbonate, comprising supplying to the bath during and / or after processing the substrate in said bath at least one of a carbon dioxide source and a lithium source in an amount sufficient to maintain the pH of the processing composition from 9.5 to 12.5, while the resulting processing composition contains lithium cation in an amount of from 5 ppm to 5500 ppm, based on lithium cation, based on the total weight of the processing composition and an anion of carbonate in an amount of from 15 ppm to 25,000 ppm, based on the carbonate anion, based on the total weight of the processing composition. 10. The method of claim 9, wherein the carbon dioxide source is a gas, a solid, or a combination thereof. 11. The method of claim 9, wherein the lithium source is lithium carbonate, lithium hydroxide, or a combination thereof. 12. The method according to claim 9, which further comprises supplying a hydroxide source to said bath. 13. The method according to claim 9, in which the amount of lithium carbonate in said bath after said feed is from 25 ppm to 30,000 ppm, based on the total amount of compound, based on the total weight of the processing composition. 14. The method according to claim 9, further comprising monitoring the pH of the bath, the amount of carbonate, the amount of lithium, or combinations thereof in said bath. 15. The method according to claim 9, further comprising adding an acid other than carbon dioxide to said bath. 16. The substrate, processed in a bath containing a composition containing lithium carbonate, to form a protective coating, characterized in that the bath is prepared by the method according to claim 9.

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