Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2000-07-13
2002-08-13
Delcotto, Gregory (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S254000, C510S255000, C510S269000, C510S271000, C510S272000, C134S003000, C134S040000
Reexamination Certificate
active
06432899
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a process for degreasing, cleaning, deoxidizing, etching and/or activating surfaces of solid objects that are constructed of and/or coated with metallic aluminum and/or aluminum alloys that contain at least 55 atomic percent of aluminum and that may be soiled with a wide variety of contaminants when the process is begun. Hereinafter, unless the context requires otherwise to be sensible or there is an express contrary indication, such as the use of the qualifier “pure” or the like, the term “aluminum” when used to describe a substrate being treated by or suitable to be treated by a process according to this invention is to be understood to include pure aluminum and all the alloys of aluminum that contain at least 55 atomic % of pure aluminum. Preferred aqueous compositions and processes of the invention provide satisfactory preparation of dean electrochemically active aluminum surfaces for use in subsequent surface finishing operations in the aerospace industry and in many other industrial uses of aluminum.
Aluminum articles in contact with the ambient natural atmosphere spontaneously develop surface layers, largely constituted of aluminum and oxygen atoms, that cause the aluminum surfaces to become electrochemically “passive”, i.e., not to undergo at any readily appreciable rate many electrochemical reactions, such as the displacement plating of copper onto the aluminum surface when it is contacted with an aqueous liquid that contains copper cations in solution, that would be expected, from thermodynamic electrode potentials for metallic aluminum, to occur readily. Before many of the surface treatment processes desired to be used on aluminum articles can be effectively undertaken, much or all of this passivating layer must be removed from any aluminum surface that has it. Removing such layers is known in the art as a “deoxidizing” or “etching” process, these terms being intended to be interchangeable herein.
1
1
In principle, “etching” requires continuing appreciable dissolution of the surface being etched during prolonged exposure of the same aluminum surface to an etching process, while “deoxidizing” could occur without such continuing dissolution, by removing only the portions of the surface initially constituted of oxides and other non-elemental forms of the underlying metal, or by transforming these portions into elemental metal or alloy, without the necessity of dissolving any of the substrate that was originally in elemental form. In practice, however, no such “ideal” deoxidizing process has ever been developed, so that achieving deoxidizing also
requires etching, and the two terms are usually used interchangeably.)
Also, many mechanical operations such as stamping, cutting, welding, grinding, drawing, machining, and polishing are used in the aluminum industry to provide shaped metal articles. In metal working operations, lubricants, antibinding agents, machining coolants and/or the like are normally utilized to prevent binding and sticking of the tools to the metal articles in the various metal working operations. The lubricants, coolants, and antibinding agents and/or the additives present in these compositions usually leave an oily, greasy, and/or waxy residue on the surface of the metal which has been worked. Any such residue initially present normally should be removed before a worked article is given a protective surface finish or incorporated into a finished assembly. Processes of this type are known as “degreasing” and/or “cleaning”, with the latter of these terms being somewhat more general, because it requires removal of all contaminant materials, with a possible exception for tightly adhering conversion coatings such as the passivating oxide layers on aluminum.
At present, it is usually practically necessary to provide distinct types of treatment compositions and processing conditions to accomplish degreasing/cleaning and deoxidizing/etching. This necessity increases the cost of processing. Accordingly, a major object of this invention is to provide compositions and processes that will practically accomplish degreasing/cleaning and deoxidizing/etching simultaneously, a combination of utilities generally denoted hereinafter as “cleaning/deoxidizing”, so that aluminum articles having greasy or otherwise soiled and at least partially passivated surfaces are made ready simultaneously for further surface treatment(s), usually including formation of a conversion coating, that enable the articles to meet the highly demanding standards of the aerospace industry, along with those of any or almost any other practical use of aluminum. Other objects will be apparent from the description below.
Except in the claims and the operating examples, or where otherwise expressly indicated, all numerical quantities in this description indicating amounts of material or conditions of reaction and/or use are to be understood as modified by the word “about” in describing the broadest scope of the invention. Practice within the numerical limits stated is generally preferred, however. Also, throughout the description, unless expressly stated to the contrary: percent, “parts of” and ratio values are by weight or mass; the term “polymer” includes “oligomer”, “copolymer”, “terpolymer” and the like; the description of a group or class of materials as suitable or preferred for a given purpose in connection with the invention implies that mixtures of any two or more of the members of the group or class are equally suitable or preferred; description of constituents in chemical terms refers to the constituents at the time of addition to any combination specified in the description or of generation in situ within the composition by chemical reaction(s) noted in the specification between one or more newly added constituents and one or more constituents already present in the composition when the other constituents are added, and does not preclude unspecified chemical interactions among the constituents of a mixture once mixed; specification of constituents in ionic form additionally implies the presence of sufficient counterions to produce electrical neutrality for the composition as a whole and for any substance added to the composition; any counterions thus implicitly specified preferably are selected from among other constituents explicitly specified in ionic form, to the extent possible; otherwise such counterions may be freely selected, except for avoiding counterions that act adversely to an object of the invention; the word “mole” means “gram mole”, and the word itself and all of its grammatical variations may be used for any chemical species defined by all of the types and numbers of atoms present in it, irrespective of whether the species is ionic, neutral, unstable, hypothetical, or in fact a stable neutral substance with well defined molecules; and the terms “solution”, “soluble”, “homogeneous”, and the like are to be understood as including not only true equilibrium solutions or homogeneity but also dispersions that show no visually detectable tendency toward phase separation over a period of observation of at least 100, or preferably at least 1000, hours during which the material is mechanically undisturbed and the temperature of the material is maintained within the range of 18-25° C.
BRIEF SUMMARY OF THE INVENTION
It has been found that at least the major object of the invention as stated above can be achieved by use of a liquid working composition combining water and at least one of glycol, “polyglycol”
2
, and glycol and polyglycol ether molecules as its two major constituents and also including alkalinizing 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, i.e., a composition ready for use as such in cleaning/deoxidizing according to the invention, comprises, preferably consists essentially of, or more preferably consists of, water
Delcotto Gregory
Harper Stephen D.
Henkel Corporation
Ortiz Daniel S.
Wisdom Norvell E.
LandOfFree
Composition and process for cleaning and deoxidizing aluminum does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Composition and process for cleaning and deoxidizing aluminum, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Composition and process for cleaning and deoxidizing aluminum will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2966925