Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2000-04-27
2002-08-27
Del Cotto, 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...
C510S245000, C510S254000, C510S270000, C510S508000
Reexamination Certificate
active
06440917
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to management of a cleaning process that removes metal salts of intermediate length carboxylic acids, i.e., fatty acids with from 10 to 22 carbon atoms per molecule, from surfaces where such salts are present over an underlying water insoluble substrate, particularly a metal substrate. (The remainder of this description will concentrate on metal substrates, but it is to be understood that it applies, mutatis mutandis, to other types of substrates that are not substantially damaged by contact with or dissolved in water.) Between the exposed surface of metal intermediate length carboxylate salt(s) and the substrate surface, there may or may not be other layers such as phosphate conversion coatings, anodized coatings, or complex oxide layers such as those that can be formed with a commercially available product named BONDERITE® 770X from the Henkel Surface Technologies Div. of Henkel Corp., Madison Heights, Mich.
Metal salts, particularly water-insoluble ones, of intermediate length carboxylic acids are widely used as lubricants for cold drawing of steel and other metals, usually over a phosphate or other conversion coating that is believed to act as a “carries” for the lubricative metal intermediate length carboxylate salt(s). After cold drawing has been completed, in most instances the metal intermediate length carboxylate salt(s) and any underlying conversion coating need to be removed before further processing of the metal article that has been cold drawn.
Such removal/cleaning has been conventionally accomplished with strongly alkaline cleaners, which preferably also contain sequestering agents for the metal cations in any underlying conversion coating, when such a coating is present, and surfactants to aid in wetting of the surface and dispersing and removing soils. However, when substantial amounts of metal intermediate length carboxylate salt(s) have been dissolved in such a cleaner, it becomes strongly prone to foaming, which causes practical difficulties in processing. Up to now, surfactant anti-foam agents have been primarily used to control such foaming, but their success leaves much to be desired in many practical operations: Even if foaming is effectively prevented, as is by no means always accomplished, solid, adherent deposits on various parts of the process equipment tend to accumulate with continued use of a fixed volume of cleaner. Spots or patches of adhering deposit also may be formed on the otherwise cleaned surfaces. Accordingly, a major object of this invention is to provide a method of avoiding impractical degrees of foaming and of adherent deposits on process equipment, or on the otherwise cleaned articles, during cleaning of metal intermediate length carboxylate salt(s) from underlying metal substrates. An alternative object is to achieve results that are more economical, more consistent in cleaning quality, or both, when cleaning metal salts of intermediate length carboxylic acids from metal substrates. Other alternative or concurrent 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 necessarily 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 by 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 one, and in favorable instances more than one, object of the invention as stated above can be achieved by using a particular type of aqueous liquid alkaline cleaning composition that comprises, preferably consists essentially of, or more preferably consists of, water and:
(A) a concentration of dissolved potassium cations; and
(B) a concentration of a component of dissolved metal cations selected from the group consisting of cations with at least one intermediate length carboxylate salt that has a solubility in water at 25° C. that is not greater than 0.15 grams per liter (hereinafter usually abbreviated as “g/l”); and, optionally, one or more of the following components:
(C) a component of dissolved chelating agent molecules;
(D) a component of dissolved surfactant molecules that are not also chelating agents;
(E) a component selected from phosphorus-containing anions that are not part of any of immediately previously recited components (A) through (D); and
(F) a component of inhibitors of at least one of corrosion, staining, or other surface blemishing of metal surfaces, said inhibitors not being part of any of immediately previously recited components (A) through (E),
said aqueous liquid alkaline cleaning composition, if it contains any dissolved sodium cations, having a molar ratio of the concentration of said sodium cations to potassium cations that is not more than 0.17:1.0. A composition according to the invention may be ready for immediate use in cleaning, in which instance it may be designated hereinafter as a “working composition”, or it may be a concentrate composition which is suitable for mixture with water and, optionally, one or more other concentrate compositions to form a working composition. Of course, some compositions according to the invention are suitable for both of these methods of use.
The relatively inexpensively available cations suitable for component (B) of a composition according to the invention as described above also have hydroxides with relatively low solubility in water and therefore can not normally be provided as solutes in substantial concentration in strongly alkaline aqueous solutions. Surprisingly, however, it has been found that if all or most of the alkali metal cations present in the composition are potassium ions instead
Church Richard J.
Hacias Kenneth J.
Conger William G.
Cotto Gregory Del
Harper Stephen D.
Henkel Corporation
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