MXPA00004248A - Composition and process for cleaning and deoxidizing aluminum - Google Patents

Abstract

Cleaning and deoxidizing aluminum surfaces can be accomplished simultaneously by contacting the surfaces with an aqueous liquid composition that contains as its cleaning active ingredients (i) alcohols and/or ether alcohols, (ii) alkaline builders, and (iii) alkali stable surfactants, and, optionally but preferably, also contains fluoride and chelating agents.

Description

COMBINATION AND PROCEDURE TO CLEAN AND DEODORIZE ALUMINUM BACKGROUND OF THE INVENTION The invention relates to a process for degreasing, cleaning, deoxidizing, chemically treating and / or activating surfaces of solid objects, which are constructed of, and / or coated with, metallic aluminum and / or aluminum alloys containing At least 55 percent atomic aluminum and that can be stained with a wide variety of contaminants, when the process begins. Next, unless the context otherwise requires being sensitive or there is an express contrary indication, such as the use of the "pure" or similar qualification, the term "aluminum", when used to describe a substrate which is to be treated or suitable to be treated by a process, according to the invention, will include both pure aluminum and all aluminum alloys containing at least 55 atomic% pure aluminum. Preferred aqueous compositions and processes of the invention provide satisfactory preparation of clean, electrochemically active aluminum surfaces for use in subsequent surface finishing operations in the aerospace industry and in many other industrial uses of aluminum.

The aluminum articles, in contact with the natural environmental atmosphere, spontaneously develop superficial layers, consisting mainly of aluminum and oxygen atoms, which cause the aluminum surfaces to become "passive" electrochemically, that is, they do not undergo a regime easily appreciable of many electrochemical reactions, such as the displacement plating of copper on the aluminum surface, when in contact with an aqueous liquid containing copper cations in solution, which would be expected, from the thermodynamic electrode potentials for aluminum metallic, that occur easily. Before effectively undertaking the use of many of the desired surface treatment processes on aluminum articles, much or all of this passivating layer must be removed from any aluminum surface that has it. The removal of such layers is known in the art as a "deoxidation" or "chemical treatment" process, these terms are intended here to be interchangeable.

- "- In principle, the" chemical treatment "requires the appreciable continuous dissolution of the surface being treated, during prolonged exposure of the same aluminum surface to a chemical process, while" deoxidation "can occur without such continuous dissolution, Removing only portions of the initially formed surface Likewise, many mechanical operations, such as stamping, cutting, welding, grinding, stretching, machining and polishing, are used in the aluminum industry to supply shaped metal articles. Metal working, lubricants, anti-joint agents, machining coolers and / or the like, are normally used to prevent adhesion or sticking of tools to metal articles in the various metalworking operations. and anti-adhesion agents and / or the additives present in these compositions, usually leave a residue oily or, oily and / or waxy on the surface of the metal which is going to work. Any residue, initially present in normal form, must be removed before it is supplied to a worked article with a protective surface finish or incorporated into a finishing set. Processes of this type are known as processes of oxides and other non-elemental forms of underlying metal, or by transforming these portions into the elemental metal or alloy, without the need to dissolve any substrate that is orignally in elemental form. However, in practice, an "ideal" deoxidation process has not yet been developed, so chemical treatment is also required to achieve deoxidation, and the two terms are used interchangeably in general. ) of "degreasing" and / or "cleaning", with the last of these terms being somewhat more general, since it requires the removal of all contaminating materials, with one possible exception for strongly adhered conversion coatings, such as passivating oxide layers on aluminum. At present, it is usually necessary, in practical form, to provide different types of treatment compositions and process conditions to achieve defatting / cleaning and deoxidation / chemical treatment. This necessarily increases the cost of the process. Therefore, a main object of this invention is to provide compositions and processes that achieve in practice the defatting / cleaning and the deoxidation / chemical treatment, simultaneously, a combination of services denoted generally immediately as "cleaning / deoxidation", so that aluminum articles, which have grease or are otherwise stained and passivated surfaces, "less partially, are simultaneously ready for one or more subsequent surface treatments, which usually include the formation of a conversion coating, which makes it possible for the articles to meet the highly demanded standards of the aerospace industry, together with those of any, or almost any other practical use of aluminum Other objects will become apparent from the following description Except in the claims and the operation examples, or where otherwise expressly indicated, all the numerical quantities in this description, indicating amounts of material or conditions of reaction and / or use, will be understood as modified by the word "approximately", in the description of the broader scope of the invention The practice within the stated numerical limits is, however, generally preferred. Also, through the description, unless expressly stated otherwise io: percent, "parts of" and values of relationships, go in weight or mass; the term "polymer" includes that of "oligomer", "copolymer", "terpolymer" and the like; the description of a group or class of materials as suitable or preferred, for a given purpose, in relation to the invention, implies that mixtures of two or more of the members of the group or class are equally suitable or preferred; the description of the constituents in chemical terms refers to the constituents at the time of addition to any combination specified in the description or generation in situ within the composition by the chemical reactions mentioned in the specification between one or more constituents recently aggregates, and one or more constituents already present in the composition, when the other constituents are added, and do not exclude unspecified chemical interactions between the constituents of a mixture, once mixed; the specification of the constituents in ionic form further involves the presence of counter-ions sufficient to produce electrical neutrality for the composition as a total or for any substance added to the composition; any counter-ion specified and intelligently, is selected as reference among other constituents explicitly specified in ionic form, the possible extent; otherwise, such counter-ions can be freely selected, except to prevent counter-ions from adversely affecting an object of the invention; the word "mol" means "mole gram" and the word itself and all grammatical variations can be used for any chemical species defined by all the types and numbers of atoms present, regardless of whether the species are ionic, neutral, unstable, hypothetical or in fact a stable neutral substance, with well-defined molecules; and the terms "solution", "soluble", "homogeneous" and the like, will be understood to include not only true solutions in equilibrium or homogeneous, but also dispersions that do not show a visually detectable trend toward phase separation over a period of time. observation of at least 100 or preferably at least 1000, hours during which the material is not mechanically altered and the temperature of the material is maintained within the range of 18 to 25SC.

BRIEF COMPENDIUM OF THE INVENTION It has been found that at least the main object of the invention, indicated above, can be achieved by the use of a liquid working composition, which combines water and at least one of the glycol, "polyglycol" 2, and glycol and polyglycol ether molecules, as their two main constituents and also include alkalizing agents and surfactant molecules, and, optionally and preferably, fluoride anions and / or chelating agents for multivalent metal cations (i.e. metal cations with at least two positive electric charges). More specifically, a working composition, ie a composition for use as such in the * • As is generally known in the art, there are condensation polymers, in which one molecule of water has been eliminated for each, except the first of the "monomers" of glycol in the polymer, which results in an oxygen bond of ether between each two carbon chains, characteristics of the glycol monomers from which the polyglycol is derived, at least formally. cleaning / deoxidation, according to the invention, comprises and preferably consists in essential form of, or more preferably consists of, water and the following dissolved components: A.) a component of organic molecules of compounds that are liquid at 25SC and are selected of the group consisting of: the compounds obtained from molecules containing at least one, preferably at least two, hydroxyl oxygen atoms and containing, otherwise, only carbon and hydrogen, and, optionally, halogen atoms, or preferably only carbon and hydrogen atoms; and compounds obtained from molecules containing at least one, or preferably at least two, oxygen atoms of ether and containing, otherwise, only carbon, hydrogen, hydroxyl oxygen and / or halogen atoms, or preferably only carbon atoms. carbon and hydrogen and, optionally, no more than one hydroxyl oxygen atom; B.) a component of an alkalizing agent, often alternatively known in the detergent art, as a "former", excluding those containing fluoride anions; and C.) a component of surfactant molecules, stable in alkali, which are not part of any of the components mentioned above immediately.

(A) and (B); and, optionally, one or more of the following components: D.) a fluoride anion components; and E.) a component of chelating agents, which are not part of any component mentioned immediately immediately (A) through (D); and F.) a component of a hydrotropic agent, which is not part of any of the components mentioned immediately before (A) to (E).

In this description, "alkali stable", when referring to a surfactant, means that the surfactant is capable of coexisting at its critical concentration of micelles or at a concentration of 5% in an aqueous solution, which also contains at least , preferably increased in the given order, 5, 10, 15, 20, 25 or 29% of sodium hydroxide, without any chemical reaction (except possibly reversible neutralization) between the surfactant and the sodium hydroxide and without the formation of any phase separated in mass detectable with normal human vision without assistance within 24 hours, or preferably, preferably increased in the given order, with 7, 30, 60, 90, 120, 180, 240, 300 or 360 days of storage, without mechanical stirring, at 252c, after being initially mixed. In addition to the working compositions, described above, embodiments of the invention include: concentrated compositions suitable for preparing the working compositions, mixing the concentrated composition with water and, optionally, other concentrated compositions; filler compositions, suitable for maintaining the cleaning / deoxidizing effectiveness of a selected amount of a working composition, according to the invention, by restoring any ingredient of the selected amount of the working composition that is removed from the amount of the composition of work during its use and what is needed to maintain its effectiveness; and process modes, which include a minimum contact of a substrate of an aluminum article with a working composition, according to the invention, to remove any stain initially present on the substrate and produce a surface that is free of any breakage of the substrate. water, when in contact with pure liquid water and spontaneously plated with copper within a period of ten minutes, after immersion at 25 ° C in an aqueous solution of copper (II) sulphate containing at least 1% copper cations (II), and may include other process steps, particularly those which are conventional in proceeding by themselves or following the chemical treatment / deoxidation and / or cleaning / degreasing of the surfaces in the prior art. In addition to the materials, necessary and optional, mentioned above, the compositions of the present invention may additionally contain germicides, preservatives or the like, and they may, and after a period of use generally do so, contain very substantial amounts of aluminum dissolved, mostly in the form of anions and aluminate. A composition of the present invention does not generally require the presence of a foam suppressing agent. The inclusion of foam suppressing agents, however, is also within the broad scope of the invention.

DETAILED DESCRIPTION OF THE INVENTION The working compositions and processes according to this invention are effective over a wide range of pH values. For primary defatting / deoxidation, prior to most subsequent operations, an alkaline working composition, according to the invention, is preferred, because it generally performs adequate degreasing more rapidly. The particular degree of alkalinity that is most preferred, generally requires a compromise between rapid degreasing, which is favored by the higher alkalinity, and avoiding excessive corrosion, which is favored by a lower alkalinity. The alkalinity is conveniently measured by the preparation of a working composition, according to the invention, and by the filling during the use of such composition by a value denoted as "free caustic", with units of grams per liter, abbreviated below as "g / 1", and measured by the following test: A sample of the liquid composition, in which the aluminum was dissolved and in which the free caustic is to be measured, was filtered, using a Buchner funnel, a flask vacuum filtration, and hardened filter paper, Whatman # 50. An aliquot of 10.0 milliliters (hereinafter abbreviated as "ml") of the filtered composition, about 30 ml of distilled, deionized or similarly pure water (hereinafter abbreviated usually as "DI water"), and about 10 ml of a soon of barium chloride in water, containing 100 g / 1 of BaCl 2, was mixed in succession in a container, such as a laboratory cover, causing the precipitation of any non-hydroxide alkalizing agent content of the liquid composition as barium salts. The mixture of the liquid and precipitate was filtered, using the same type of filtration equipment as before, except that a glass fiber filter, having a pore size of 1.2 microns (hereinafter abbreviated usually as "μm") was used. instead of the filter paper. The vessel was rinsed twice with a volume of 30 and 50 ml of DI water each time, with the rinse water being filtered through the same filter as, and collecting the filtrate from, the first filtration after the addition of the soon of BaCl2. The water remaining in the container was then tested with pH paper, which should indicate a neutral pH, if it does not, an additional rinse with DI water should be continued until the remaining water reaches a neutral pH, using a volume of water of extra rinse as small as possible to achieve this purpose. After completing all the rinsing, the filtration should be continued until the filtered precipitate dries and no more drops of liquid are seen to pass through the funnel. The filtered liquid is then titrated with a 1.00 N HCl soon to a white cloudy end point (precipitation of the hydrous aluminum oxide as the pH of the liquid phase falls). The value of the free caustic in g / 1 is 5.6 times the number of ml of the 1.00 N acid soon consumed in the titration. It is also convenient to determine the dissolved aluminum content in the original composition. Four drops of the phenolphthalein indicator soon were added to the titration mixture at this point, and the titration was continued until the pink color disappeared. The number of additional ml of acid 1.00 N required to reach the second end point, multiplied by 2.67, gives the value of g / 1 of the aluminum dissolved in the original composition. If the composition does not contain aluminum, the free caustic is determined in the same way, except that the indicator soon of phenolphthalein is added to the filtrate immediately, and the titration is in the disappearance of the pink color; no precipitate should be formed during this titration.

For applications of the aerospace industry, when cleaning / deoxidation is desired, specifically when a layer of 5 μm deep inside the surface must be removed from the substrate, during no more than 15 minutes of the contact time between the surface of the substrate and the liquid cleaning / deoxidizing composition, but the total depth of the material removed during a complete cleaning / oxidation process in a given substrate article, may not exceed of 5 μm, the free caustic value of a working composition, according to the invention, is preferably at least, preferably increased, in the given order, 2, 4, 6, 8, 10, 12 or 14 g / 1 and preferably, independently, is, preferably increased in the given order, no greater than 120, 100, 80 or 60 g / 1, unless exceptionally faster chemical treatment regimes are desired, more preferably not greater , preferably increased in the given order, of 55, 50, 45, -35 or 30. Minor values within these preferences are usually preferred when the content of aluminum dissolved in the composition is relatively low and higher values are p normally referred to when the content of aluminum dissolved in the composition is relatively high, in order to maintain a constant rate of chemical treatment, as part of the cleaning / deoxidation process, according to the invention.

The component (A) is preferably selected from molecules each of which contains at least two ether oxygen atoms and a hydroxyl oxygen atom and otherwise contains only carbon and hydrogen atoms and, optionally, halogen atoms; more preferably, mainly for reasons of economy, these molecules do not contain halogen atoms. Independently, the component (A) is preferably selected from molecules, each of which contains at least, preferably increased in the given order, 2, 4, 6 or 8 carbon atoms and preferably, independently, contains no more of, preferably increased in the given order, 18, 16, 14 or 10 carbon atoms. Independently of all other preferences, component (A) is furthermore selected from substances that are sufficiently soluble in water, to form a solution containing at least, preferably increased in the given order, 2, 5, 10, 12, 15 , 18 or 20% of the substances selected for component (A). The most preferred single material for component (A) is one generally known as "diethylene glycol monobutyl ether", which has the chemical formula HO-C2H4-O-C2H4-O-C4H9. Regardless of its exact chemical constitution, the component (A) in the working composition, according to the invention, is preferably present in a concentration of at least, preferably increased in the given order, of 2, 5, 10, 12 , 15, 17, 18.0, 19.0, 19.5 or 19.9% and independently, preferably, primarily for reasons of economy, no more than, preferably increased in the given order, 75, 50, 35, 30, 27, 25, 23 or 21%. The alkalizing component (B) is preferably selected from various inorganic salts and hydroxides, known as useful as "inorganic formers" in cleaning formulations in general. The trainers • inorganic, except for hydroxides, are generally salts of polyfunctional inorganic acids, such as alkali metal silicates, alkali metal borates, alkali metal carbonates, alkali metal sulfates, alkali metal polyphosphates, alkali metal phosphates, orthophosphates of alkali metals and alkali metal pyrophosphates. Salts, such as sodium silicate, sodium metasilicate, sodium orthosilicate, sodium tetraborate, sodium borate, sodium sulfate, sodium carbonate, trisodium phosphate, disodium orthophosphate, sodium metaphosphate, sodium pyrophosphate, salts of potassium corresponding to all of them, the sodium and potassium hydroxides, and the like, are all alkalizing agents suitable for the compositions according to the invention. Lithium, rubidium and cesium salts and hydroxides are also suitable, although usually less preferred, due to their higher cost, and the ammonium salts are technically suitable, but are generally avoided due to the opportunity of loss by volatilization and odor Annoying companion of ammonium fumes. Due to the higher solubility, potassium cations are preferred over sodium cations in many cases in the constituents of the alkalizing component (B), despite their slightly higher cost. More preferably, in a composition, according to this invention, a hydroxide of an alkali metal and an alkali metal hydroxide of a polyfunctional inorganic acid are both part of the component (B). More particularly, a freshly prepared working composition, according to the invention, free from dissolved aluminum, preferably contains hydroxide ions in a concentration that is at least, preferably increasing in the given order, of 0.05 0.10, 0.15, 0.20, 0.25, 0.30, 0.35m 0.40 or 0.43% of the total composition and preferably, independently, not greater than, with increasing preference in the given order, of 3.0, 2.5, 2.0, 1.5, 1.0, 0.80, 0.70, 0.65, 0.60, 0.55, 0.50, or 0.45 of the total composition (The specified concentrations are preferred in this paragraph and are understood to include all the stoichiometric equivalent as CH ~, of all the soluble hydroxides added in the course of the preparation of a composition, according to the invention, unless some of this content has been removed by physical means.) The free caustic value, determined as described above, is the strongest compositional influence in the chemical treatment regime obtained with a composition according to the invention, the chemical treatment regime increases with the increasing value of the free caustic. This value of free caustic in a preferred composition, freshly prepared, according to the invention, is almost equivalent to the concentration, expressed in g / 1, of the stoichiometric equivalent as the KOH of the concentration of hydroxide ions in the same composition, but as the composition of use, much of the content of the hydroxide ions, originally added, becomes aluminate anions, which do not contribute a substantial amount to the free caustic value. Independently, a composition, according to the invention, which contains both hydroxide and non-hydroxide materials, for component (B), preferably contains the non-hydroxide materials, which are preferably independently selected from the group consisting of of the fully neutralized ales of polyfunctional inorganic acids, in a concentration that is at least, preferably increasing in the given order, of 0.010, 0.020, 0.030, 0.040. 0.050, 0.055, 0.060, 0.065 or 0.070 moles of alkalizing agents not of hydroxide per kilogram of the total composition, this unit of concentration is then freely applied to any other solute, as well as alkalizing agents not of hydroxide and then abbreviated usually as "M / kg". The concentration of the non-hydroxide alkalizing agents preferably, independently, is not greater, preferably increased in the given order, of 0.50, 0.40, 0.30, 0.20, 0.17, 0.14, 0.12, 0.10 or 0.08 M / kg. Carbonates are the simplest non-hydroxide alkalizing agents most preferred in a composition, according to the invention, in that they can normally be filled, to an extent insufficient than their necessary filler, by the absorption of carbon dioxide from the ambient atmosphere natural. Component (C) preferably contains two sub-components. The preferred subcomponent (Cl) is selected from the group consisting of the surfactant Alkali Surfactant JEN 2700 ™, commercially available from Tomah Chemical Products, Milton, Wisconsin and reported by its supplier as a solution in water of about 35% of its ingredient. surface-active agent, the monosodium salt of iso-decyloxypropylaminodipropionic acid, an amphoteric surfactant, and SURMAX ™ surfactants CS-504, -515, -521, -522, -555, -634, -684, -727, -772 and -786., All commercially available from Chemex, Inc., Greenville, South Carolina and reported by its supplier as alkali-stable, amphoteric-anionic surfactants, including organic esters, and / or organic ester salts , of phosphoric acid with other patented compositional information. The concentration of the subcomponent (Cl) in a composition, according to the invention, is preferably at least, preferably increasing in the order, of 0.02, 0.04, 0.08, 0.10, 0.12, 0.14, 0.16, 0.18, or 0.20, of the total composition and preferably, independently, not greater than, "with increasing preference in the order of 1.0, 0.90, 0.80, 0.70, 0.60, 0.50, 0.40, 0.35, 0.30 or 0.25% of the total composition. The preferred subcomponent (C.2) is selected from the group consisting of alkyl phenol ethoxylates, more preferably octyl and nonyl phenols, these ethoxylates preferably, independently, have a hydrophilic-lipophilic balance value (below) abbreviated as "HLB") which is at least, with increasing preference in 9.0, 10.0, 11.0, 12.0, 12.5, 13.0 or 13.4 and preferably, independently, not greater than, with increasing preference in the given order, of 16.0, 15.0, 14.5, 14.1, 13.8, or 13.6. Independently, the concentration of the subcomponent (C.2) in a composition, according to the invention, is preferably at least, with increasing preference in the given order, of 0.05, 0.10, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45. or 0.48% of the total composition and independently, preferably, not greater than, with increasing preference in the given order, of 3.0, 2.5, 1.5, 1.2, 0.90, 0.70, 0.60 or 0.52% of the total composition. When the subcomponents (Cl) and (C.2), as defined above, are both present in a composition, according to the invention, the ratio of the concentrations, expressed in the same units, of the subcomponents (Cl) and (C.2) in the composition, preferably are at least, preferably increasing in the given order, of 0.10: 1.0, 0.15: 1.0, 0.20: 1.0, 0.30: 1.0, 0.35: 1.0, or 0.40: 1.0 and preferably, independently, not greater than, with increasing preference in the given order of 1.01.0, 0.80: 1.0, 0.70: 1.0, 0.60: 1.0, 0.55: 1.0 or 0.50: 1.0. The presence of the optional component (D) of fluoride anions in a working composition, according to the invention, is usually preferred, because it favors a uniform surface appearance in completing the cleaning / deoxidation process, according to the invention . However, if this is not important in a particular application, component (D) can be omitted. The fluoride ions may be provided to a composition, according to the invention, by any salt sufficiently soluble in water and acids containing simple or complex fluoride anions, and when presumed to be so supplied, for the purpose of calculating the content of the fluoride anions of the composition, will be present in the stoichiometric extension of the anions containing the fluorine atom, in the materials dissolved in the composition, independent of the actual extent of the ionization that may exist in the composition.

Primarily for reasons of economy, the sources of • simple fluoride anions are generally preferred and because of the high preferred alkalinity for the composition as a whole, the salts are preferred over the acids as the source of fluoride anions. The same counterions in these salts, as those described above, for the alkalizing component (B) are preferred for the component (D) for the same reasons. Potassium fluoride is the most preferred single source of component (D). In a dissolved working composition prepared freshly or otherwise, according to the invention, the concentration of fluorine in the form of fluoride anions is preferably at least 0.02, 0.04, 0.06, 0.08, 0.10, 0.12, 0.14 or 0.16 parts per thousand parts of the total composition, a concentration unit that can be freely applied later to any other constituent of the composition as well as fluorine, is usually abbreviated "ppt" and independently of preference is not greater than 1.0, 0.80, 0.60, 0.40, 0.35, 0.30, 0.25 or 0.20 ppt. Because the fluoride anions are complex agents at least moderately effective for aluminum (III) cations, the conversion of them partially to the hexafluoroaluminate (III) anions, after a composition, according to the invention, has been in use for some other reason contains a substantial amount of dissolved aluminum, the fluoride content of the composition is preferably controlled by a so-called "free fluoride" measurement, rather than by the total fluorine content of the composition. "Free fluoride" is measured by the use of an ion-specific electrode and associated equipment known to those skilled in the art. The value of the free fluoride of a freshly prepared composition, according to the invention, should preferably be measured and used as a target for fluoride additions, when these additions are necessary as the composition is used, to restore the value of the free fluoride original for the freshly prepared composition.

The optional chelating component (E) is generally preferred in most compositions according to the invention. Any material recognized in the art as a chelating agent for the cations of aluminum, calcium and / or magnesium, in the aqueous solution can be used. The exact function of the chelating agent is not known, but it has at least two potentially valuable functions: as a chelating agent for aluminum, it can promote the chemical treatment regime of a composition that contains it, and as a chelating agent for calcium and magnesium, you can make use of tap water instead of DI water in a satisfactory way in some cases. Preferred chelating agents include organic compounds, sufficiently soluble in water, and the metal salts of these compounds, such as organic acids containing at least two parts of -OH (which may or may not be part of the carboxyl), placed within the molecules of the compounds in some way that the oxygen atoms are separated from each other by at least two carbon atoms. Examples of such organic compounds include nitriloacetic acid ("NTA"), ethylene diamine tetraacetic acid ("EDTA", tartaric, malic and gluconic acids and their salts, and saccharides (sugars), with the latter being preferred and the Especially preferred sorbitol Independently of the exact chemical constitution, the concentration of the chelating agent component in a working composition, according to the invention, is preferably at least, preferably increasing in the given order, of 0.02, 0.04, 0.06, 0.08, 0.10, 0.12 or 0.14% of the total composition and preferably, independently, not greater than, with increasing preference in the given order, of 1.0, 0.8, 0.6, 0.40, 0.35, 0.30, 0.25, 0.20 or 0.15% of the total composition The optional hydrotropic component (F) is not generally needed in most work compositions, in accordance with this invention, in part because many of the preferred constituents of component (C) have some hydrotropic effect, but are useful in a preferred filler composition, as mentioned below. Conventional hydrotropic agents, such as the salts of alkylbenzenesulfonic acids, particularly cis-sulfonic acid, are suitable for the compositions to achieve the cleaning purpose of this invention, but may interfere with the last intended use of Substrates to be cleaned, due to very low tolerances for residual sulfur on the surface are specified for many aerospace applications. Other types of hydrotropes are, therefore, preferred, when an additional hydrotrope is necessary for most formulations, according to the invention. Organic phosphate esters and cyclic acid anhydrides, substituted with alkyl and alkenyl, particularly the anhydrides of C4_6 terminal dicarboxylic acids substituted with alkyl or alkenyl groups, having 6 to 20 carbon atoms, are both useful. A particularly preferred example of this type of hydrotrope is non-n-succinic anhydride. These two types are even more preferred in mutual combination, in a ratio of the phosphate esters to the substituted cyclic anhydrides which is preferably, preferably increasing in the given order, of at least 0.1, 0.2, 0.4, 0.6, 0.80, 0.90. , 1.00, 1.10, 1.20, 1.30, 1.40, 1.50 or 1.55 and preferably, independently, is, with increasing preference in the given order, no greater than 20, 15, 10, 7, 5, 4, 3, 2.7, 2.4, 2.2, 2.0, 1.9, 1.8, 1.75, 1.70 or 1.65. A particular commercial hydrotropic agent, AMPHOTERIC SC, from To ah Products, Inc., with a chemical constitution unknown to the applicant, except that its active ingredients are "based on alkyliminodipropionates" and constitute 35% of the total composition, as supplied commercially (the rest presumably is water); It has also been found to be effective and the most preferred. The amount of the hydrotropic agent is not believed to be critical, but it must be sufficient to achieve its purpose and, for reasons of economy, preferably it is little or no greater than this sufficient value. As a general guide, the amount of the hydrotropic agent in a main filling composition, according to the invention, which includes at least 7% potassium hydroxide and at least 0.1% nonionic surfactants, is preferably at least , preferably increased in the given order, of 0.1, 0.3, 0.5, 0.7 or 0.9% and preferably, independently, not greater than, with increasing preference in the given order, of 11, 7, 5, 3, 2.0 or 1.1% As would be expected, in view of some of the above discussions, the ingredients of a composition, according to the invention, are not depleted during use in the same proportions as are present in the preferred work composition, obtained recently, according to with the invention It has been found that two fillers are preferred, one containing only fluoride anions and their counter-ions as active ingredients, and another containing all other ingredients of a preferred work composition, according to the invention, except the alkalizing agent. not hydroxide, if the latter is a carbonate salt, as is most preferred, plus a hydrotropic agent, but with considerably higher concentrations of component (B), and smaller concentrations of the other necessary components and optional chelating agents, but preferred. More particularly a main filling composition, according to the invention, is a liquid which, in addition to water, preferably comprises, more preferably consists of essential of, or even more preferably consists of the following concentrations of the components, already defined by the Last identifiers for the work compositions: > the component (A) is preferably present in a concentration of at least, preferably increasing in the given order, 0.44, 1.1, 2.2, 2.6, 3.3m 3.7, 4.0, 4.10, 4.20 or 4.30% and preferably, independently, for "economy reasons, not more than, with increasing preference in the given order, of 17, 11, 8.8, 7.7, 6.6, 6.0, 5.5, 5.0, or 4.5%;> hydroxide ions are preferably present in a concentration of at least, with increasing preference in the given order, of 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0 or 4.3% of the total composition and preferably, independently, no greater than, with increasing preference in the given order, of 30.25, 20, 15, 10, 8.0, 7.0, 6.5, 6.0, 5.5, 5.0 or 4.5% of the total composition;> the sub-component (Cl) is preferably present at a concentration which is at less, with increasing preference in the given order, of 0.05, 0.009, 0.019, 0.023, 0.030, 0.033, 0.037, 0.042 or 0.047% of the composition t otal and preferably, independently, not greater than, with increasing preference in the given order, 0.23, 0.21, 0.19, 0.16, 0.14, 0.12, 0.093, 0.081, 0.069 or 0.058% of the total composition; > the subcomponent (C.2) is preferably present in a concentration that is at least, preferably increasing in the given order, of 0.02, 0.04, 0.07, 0.090, 0.095, 0.100, 0.105 or 0.110% of the total composition and preferably, independently, not greater than, with increasing preference in the given order, 1.1, 0.9, 0.7, 0.50, 0.35, 0.23, 0.18, 0.14 or 0.12% of the total composition; > a chelating agent component is preferably present at a concentration that is at least, preferably increasing in the given order, 0.004, 0.008, 0.012, 0.016, 0.020, 0.024 or 0.028 of the total composition and preferably, independently, not greater than, with increasing preference in the given order, 0.20, 0.16, 0.12, 0.080, 0.070, 0.060.0.050, 0.040 or 0.030% of the total composition.

Powdered solid potassium fluoride is effective and inexpensive and, therefore, generally more preferred as supplemental fluoride filler, but if a liquid filler should be preferred, for example due to the better adaptability to automatic filling, in response to The signals from the electrode that detects the free fluoride, a solution in water from any suitable source of fluoride can be used. The aluminum articles to be cleaned / deoxidized should be brought into contact with the aqueous liquid cleaning / deoxidation composition, according to the present invention, at a sufficient temperature, for a sufficient time, to be effective for this cleaning / deoxidation . Normally, the temperature of a working composition, according to the invention, during its actual use, is preferably at least 32 ° C. Higher rates of chemical treatment will be achieved at higher temperatures, as illustrated in the following examples, and a temperature of at least one can be used satisfactorily if a high rate of chemical treatment is desired. Contact times between the cleaning / deoxidation composition and the substrate to be cleaned / deoxidized, in the process according to the invention, are preferably between 1 and 15 minutes. The invention is particularly advantageously applied to aluminum substrates containing at least, preferably increasing in the given order, 65, 75, 85 or 90 atomic percent pure aluminum. The following examples illustrate the compositions and methods of the present invention. The examples are for illustrative purposes only and are not intended to limit the invention.

EXAMPLES OF WORK COMPOSITION AND PROCESS The ingredients and amounts of each used in the two work compositions, according to the invention, are shown in the following Table 1. Both of these compositions were tested for cleaning / deoxidation at least one of the AA2024 AA6061 and AA7075 types of aluminum substrates at various different temperatures and for each composition at each temperature, a substantially linear correlation between the exposure time and the thickness of the material removed during contact times of up to 20 minutes was achieved and designated as the "chemical treatment regime". These chemical treatment regimes are shown in the following Table 2. A major filler, suitable for use in filling any of Composition 1 or Composition 2, has the composition shown in the following Table 3.

VARIATION OF THE REGIME OF THE CHEMICAL TREATMENT WITH THE CONCENTRATION OF DISSOLVED ALUMINUM The values of the regime of the chemical treatment given in Table 2 with for solutions that do not contain dissolved aluminum at the beginning of its use. When Composition 1, as shown in Table 1, has accumulated about 39 g / 1 of dissolved aluminum, its initial free caustic value has been restored by the necessary additions of the main filling composition, shown in Table 3, and its concentration of free fluoride has been restored, if necessary, by the addition of potassium fluoride; the chemical treatment regime at 542C is about 98% of its value when the composition was recently obtained. Under the same conditions, when the accumulated concentration of dissolved aluminum reaches about 42 g / 1, the chemical treatment regime is only 93% of its initial value, and when the dissolved aluminum reaches a concentration of approximately 53 g / 1, the chemical treatment regime is only 88% of its original value. If desired, the original regimes can be restored by increasing the free caustic value of the composition.

TABLE 1 Examples of working compositions, according to the invention Note for Table 1 TRITON ™ X-100 was commercially supplied by Union Carbide Corp., and reported by its supplier, is a 100% active mixture of octylphenol poly (ethoxy) ethanol molecules with an HLB value of 13.5.

TABLE 2: Chemical treatment regimes at various temperatures Note for Table 2 The numbers of the work compositions are those of Table 1.

TABLE: Example of the main filling composition, according to the invention

Claims (36)

1. CLAIMS 1. A liquid, aqueous material composition suitable for cleaning / deoxidizing aluminum surfaces, this composition comprises water and the following dissolved components: A.) a component of organic molecules of compounds that are liquid at 252C and are selected from the group consisting of: the compounds obtained from molecules containing at least one hydroxyl oxygen atom and containing, otherwise, only carbon and hydrogen atoms; and compounds obtained from molecules which contain at least one ether oxygen and which do not otherwise contain atoms in addition to the carbon-, hydrogen, ether oxygen, hydroxyl oxygen and halogen atoms; B.) a component of an alkalizing agent, excluding any that contains fluoride anions; and C.) a component of molecules of an alkali-stable surfactant, which is not part of any of the components (A) and (B), mentioned immediately above.
2. 2. The aqueous liquid composition of claim 1, wherein the component (A) is selected from molecules each of which contains at least two oxygen atoms of ether and one hydroxyl oxygen atom and, otherwise, only hydrogen atoms. carbon and hydrogen.
3. 3. The aqueous liquid composition of claim 1, wherein the component (A) is selected from molecules, each of which contains at least 2 carbon atoms and no more than 18 carbon atoms.
4. 4. The aqueous liquid composition of claim 1, wherein the component (A) is selected from substances that are sufficiently soluble in water, to form a solution containing at least 2% of the substances selected for the component (A).
5. 5. The aqueous liquid composition of claim 1, wherein component (A) comprises diethylene glycol monobutyl ether.
6. 6. The aqueous liquid composition of claim 1, wherein the amount of the component (A) is about 2 to 75%, based on the total weight of the aqueous liquid composition.
7. 7. The aqueous liquid composition of claim 1, wherein the component (B) is selected from the group consisting of alkali metal hydroxides, alkali metal silicates, alkali metal borates, alkali metal carbonates, alkali metal sulfates, polyphosphates of alkali metals, alkali metal phosphates, alkali metal orthophosphates and alkali metal pyrophosphates, and combinations thereof.
8. 8. The aqueous liquid composition of claim 1, wherein the component (B) comprises an alkali metal hydroxide and an alkali metal salt of a polyfunctional inorganic acid.
9. 9. The aqueous liquid composition of claim 1, which is free of dissolved aluminum and contains hydroxide ions in a concentration that is between about 0.05 and 3.0% of the total composition.
10. 10. The aqueous liquid composition of claim 9, wherein the amount of the alkali metal salt of the polyfunctional inorganic acid is from about 0.010 to 0.50 moles per kilogram of the total composition.
11. 11. The aqueous liquid composition of claim 9, wherein the alkali metal salt of the polyfunctional inorganic acid is a carbonate.
12. 12. The aqueous liquid composition of claim 1, wherein component (C) comprises a subcomponent (C.l), selected from the group consisting of the monosodium salt of isodecyloxypropylaminodipropionic acid, organic esters of phosphoric acid, and salts of organic esters of phosphoric acid.
13. 13. The aqueous liquid composition of claim 12, wherein the amount of the component C.l is at least about 0.02% and not more than about 1.0% of the total composition.
14. 14. The aqueous liquid composition of claim 1, wherein component (C) comprises a subcomponent (C.2), selected from the group consisting of alkylphenol ethoxylates.
15. 15. The aqueous liquid composition of claim 14, wherein the ethoxylates have a hydrophilic-lipophilic equilibrium value that is at least about 9.0 and no greater than 16.0.
16. 16. The aqueous liquid composition of claim 14, wherein the amount of the subcomponent (C.2) is at least about 0.05% of the total composition and not more than about 3.0% of the total composition.
17. 17. The aqueous liquid composition of claim 12, further comprising a subcomponent (C.2), selected from the group consisting of alkylphenol ethoxylates.
18. 18. The aqueous liquid composition of claim 17, wherein the ratio of the amounts of the subcomponents (C.l) and (C.2) is at least about 0.10: 1.0 and not greater than about 1.0: 1.0.
19. 19. The aqueous liquid composition of claim 1, further comprising a component (D), which includes fluoride anions.
20. 20. The aqueous liquid composition of claim 19, wherein the amount of fluoride anions is at least about 0.02 parts per thousand parts of the total composition and not more than about 1.0 part per thousand parts of the total composition.
21. 21. The aqueous liquid composition of claim 1, further comprising a chelating agent, which is not part of any of the components (A) to (C).
22. 22. The aqueous liquid composition of claim 21, wherein the chelating agent comprises an organic water-soluble compound, containing at least two parts of -OH, placed within the compound molecule, so that the two oxygen atoms are separate each other by at least the carbon atoms.
23. 23. The aqueous liquid composition of claim 21, wherein the amount of the chelating agent is at least about 0.02% of the total composition and not more than about 1.0% of the total composition.
24. 24. The aqueous liquid composition of claim 1, further comprising a hydrotropic compound.
25. 25. The aqueous liquid composition of claim 1, this composition consists essentially of water and the following dissolved components: about 17 to 25% of the diethylene glycol monobutyl ether, based on the total weight of the aqueous liquid composition; an amount of potassium hydroxide, which corresponds stoichiometrically at a concentration of about 0.35 to 0.55%, based on the total weight of the aqueous liquid composition; about 0.060 to 0.10 moles of potassium carbonate per kilogram of the aqueous liquid composition; approximately 0.16 to 0.35%, based on the total composition of a surfactant, selected from the group consisting of the monosodium salt of iso-decyloxypropyl amine dipropionic acid, organic esters of phosphoric acid and salts of the organic esters of phosphoric acid, and their mixtures; about 0.40 to 0.60%, based on the total composition, of a surfactant, selected from the group consisting of octyl- and nonyl-phenol poly (ethoxy) -ethanol molecules, the latter surfactant mentioned, as a total, which has a value of HLB that is approximately 12.0 to 15.0; an amount of potassium fluoride, which imparts to the total composition a value of free fluoride possessed by a total reference composition, which does not contain dissolved aluminum cations, but, otherwise, contains from about 0.12 to 0.30 ppt of anions of dissolved fluoride, together with all the other ingredients of the actual total composition; and about 0.10 to 40% sorbitol, based on the total weight of the aqueous liquid composition.
26. 26. An aqueous liquid composition of material suitable for cleaning / deoxidizing aluminum surfaces, this composition has been obtained by mixing with a first water body at least the following masses, which dissolve in the first body of water, when mixed with it: A.) a second mass of molecules, selected from the group consisting of organic molecules of compounds that are liquid at 252C, these molecules further (i) contain at least one hydroxyl oxygen atom and otherwise contain only hydrogen atoms, or (ii) contain at least one ether oxygen atom and, otherwise, do not contain atoms other than carbon atoms, hydrogen, hydroxyl oxygen, ether oxygen, and halogen atoms; B.) a third mass of an alkalizing agent, excluding any that contains fluoride anions; and C.) a fourth mass of alkali stable surfactant molecules, which are not part of any of the components (A) and (B), mentioned immediately above.Hey
27. 27. The aqueous liquid composition of claim 26, wherein the second mass constitutes at least about 5% of the total aqueous liquid composition and the third mass includes hydroxyl ions, which constitute about 0.10% of the total aqueous liquid composition.
28. 28. The aqueous liquid composition of claim 27, wherein: the mass (A) is selected from molecules, each of which contains at least two oxygen atoms of ether and one hydroxy oxygen atom, and, otherwise, tdo not contain more atoms, except the carbon, halogen and hydrogen atoms, these last mentioned molecules, each one includes at least 2 carbon atoms and no more than 18 carbon atoms; the mass (B) is selected from the group consisting of alkali metal hydroxides, alkali metal silicates, alkali metal borates, alkali metal carbonates, alkali metal sulfates, alkali metal polyphosphates, alkali metal phosphates, metal orthophosphates Alkali metals and alkali metal pyrophosphates; the mass (C) includes a sub-mass (Cl), selected from the group consisting of the monosodium salt of iso-decyloxypropylaminodipropionic acid, organic esters of phosphoric acid, salts of organic esters of phosphoric acid, and mixtures thereof, and a different sub-mass ( C.2), selected from the group consisting of alkylphenol ethoxylates, the sub-mass (Cl) constitutes at least about 0.04% of the total composition, the sub-mass (C.2) constitutes at least about 0.10% of the total composition, and the sub-mass (Cl) has a relation to the sub-mass (C.2) that is from 0.20: 1.0 to 0.80: 1.0; there is also a fifth mass (D) in mixture to obtain an aqueous liquid composition of fluoride anions, which imparts to the total composition a value of the free fluoride possessed by a total reference composition, which does not contain dissolved aluminum cations, but , otherwise, it contains from about 0.04 to 0.60 ppt of dissolved fluoride anions, along with all other ingredients of the current total composition; and there is a sixth mass in admixture to obtain an aqueous liquid composition, of a chelating agent, selected from the group consisting of nitrilotriacetic acid, ethylenediamine tetraacetic acid, citric acid, tartaric acid, malic acid, gluconic acid, salts of all acids mentioned immediately above, and saccharides, this sixth mass constitutes from about 0.04 to 0.6% by weight of the total aqueous liquid composition.
29. 29. The aqueous liquid composition of claim 28, wherein: the mass (A) is selected from molecules that do not contain halogen atoms and from 4 to 14 carbon atoms; the mass (B) includes a sub-mass (Bl) of alkali metal hydroxides, containing hydroxide ions which constitute approximately 0.25 to 0.70% of the total composition and a sub-mass (B.2) selected from the group consisting of silicates of alkali metals, alkali metal borates, alkali metal carbonates, alkali metal sulfates, alkali metal polyphosphates, alkali metal phosphates, alkali metal orthophosphates and alkali metal pyrophosphates, all neutralized completely, and the sub-mass (B.2) it contains a number of moles corresponding to about 0.020 to 0.20 moles per kilogram of the total composition; the sub-mass (Cl) constitutes approximately 0.08 to 0.60% of the total composition, the sub-mass (C.2) constitutes approximately 0.25 to 1.5% of the total composition, and the sub-mass (Cl) has a relation to the sub-mass (C) .2) which is from 0.25: 1.0 to 0.60: 1.0.
30. 30. The aqueous liquid composition of claim 29, wherein the following is first mixed with water to obtain an aqueous liquid composition: a second mass of diethylene glycol monobutyl ether, which constitutes approximately 17 to 25% of the total mass of the aqueous liquid composition; a sub-mass (B.l) of potassium hydroxide, which corresponds stoichiometrically to a concentration of hydroxide ions which is approximately 0.35 to 0.55%, based on the total mass of the aqueous liquid composition; a sub-mass (B.2) of potassium carbonate, which constitutes approximately 0.060 to 0.10 moles of potassium carbonate per kilogram of the aqueous liquid composition; a submamma (C.l) that constitutes from approximately 0.16 to 0.35%, based on the total composition; a sub-mass (C.2) constituting approximately 0.40 to 0.60% of the total mass of the aqueous liquid composition and selected from the group consisting of octyl- and nonyl-phenol poly (ethoxy) ethanol molecules, this sub-mass (C .2) as a total has a value of HLB that is approximately 12.0 to 15.0; an amount of potassium fluoride, which imparts to the total composition a free fluoride value, possessed by the total reference composition, when it contains approximately 0.12 to 0.30 ppt of dissolved fluoride anions; and a mass of sorbitol ,. which constitutes approximately 0.10 to 0.40% of the total composition.
31. 31. A method for cleaning / deoxidizing an aluminum substrate, this method comprises an operation of contacting the substrate with an aqueous liquid cleaning / deoxidation composition, according to any of claims 1 to 30, with a sufficient temperature and for a enough time to make the cleaning / deoxidation effective.
32. 32. The method of claim 31, wherein the sufficient temperature is at least about 322C.
33. 33. The method of claim 31, wherein sufficient time is approximately 1 to 15 minutes.
34. 34. The method of claim 31, wherein the aluminum substrate contains at least 65 atomic percent of pure aluminum.
35. 35. An aluminum substrate, which has been cleaned / deoxidized by the method of claim 31.
36. 36. A concentrated, liquid, aqueous composition suitable for filling the liquid compositions used to clean / deoxidize aluminum surfaces, in a process according to claim 31, this concentrated composition comprises water and the following dissolved components: approximately 0.44 to 17%, based on the total weight of the concentrated, liquid, aqueous composition of a component of organic molecules of compounds that are liquid at 252C, these molecules contain: (i) at least one hydroxyl oxygen atom, and , otherwise, only carbon and hydrogen atoms, or (ii) at least one ether oxygen atom, and, otherwise, no atom other than the carbon atoms, hydrogen, hydroxyl oxygen and halogen atoms; a component of an alkalizing agent, including hydroxyl ions, in an amount sufficient to constitute about 0.05 to 30.0% of the total composition; about 0.005 to 0.23% of an alkaline stable surfactant, selected from the group consisting of the monosodium salt of iso-decyloxypropyl aminopropionic acid, organic esters of phosphoric acid, salts of organic esters of phosphoric acid and their mixtures; about 0.02 to 1.1% of an alkali-stable surfactant, of the group consisting of the alkylphenol ethoxylates; and about 0.004 to 0.20% of a chelating agent, selected from the group consisting of water-soluble organic compounds, containing at least two parts of -OH, placed within the compound molecule, so that the two atoms of oxygen from the two -OH parts are separated from each other by at least two carbon atoms.