Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Liquid composition
Reexamination Certificate
1996-10-04
2002-04-16
Shah, Mukund J. (Department: 1624)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Liquid composition
C510S423000, C510S433000
Reexamination Certificate
active
06372706
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a process for cleaning hard surfaces, particularly those of metal objects, which are contaminated with oil or similar materials that are widely used as lubricants in machining and/or as temporary protection against corrosion. Such oily materials normally must be substantially totally removed from a metal surface in order to prepare it for uniform formation on the surface of a coating that will provide long term protection against corrosion.
The term “alkaline cleaning solutions” as used herein includes all aqueous solutions that contain (i) at least one dissolved alkalinizing constituent, such as alkali or alkaline earth metal hydroxides, carbonates, borates, phosphates, or silicates and (ii) either no off-setting acid or an amount of such acid that leaves the total composition with a pH greater than 8. The borates, phosphates, and silicates in this class include both simple and condensed types, such as metasilicate, pyrophosphate and tripolyphosphate, and borax and the like. The alkali and alkaline earth metals include particularly sodium, potassium, magnesium, calcium, barium, and the like. More particularly this invention relates to such cleaning solutions, and concentrates for making them, that contain hydroxide(s) as the sole or at least the most predominant alkalinizing constituent.
2. Statement of Related Art
Normally, alkaline cleaner compositions now used for metal surface preparation contain a surfactant component, which may be a single chemical type of surfactant or a mixture of such chemical types, including any or all of the classes of anionic, cationic, amphoteric ionic, and nonionic surfactants. (Cationic surfactants are less commonly used than the other types in metal cleaning formulations, because they are more likely to affect the subsequent processing and treatment of the metal surface in some manner that may be adverse.) Nonionic surfactants are generally preferred for cleaning power, but are not readily dissolved in highly concentrated aqueous solutions of hydroxide, which are desirable for economic reasons to minimize the cost of shipping water: If a highly concentrated liquid can be supplied as a strong alkaline cleaner concentrate, working cleaning solutions that contain the alkaline ingredients from the concentrate can be more economically prepared with local water supplies at the point of use.
It is known that the dissolution of nonionic surfactants into concentrated alkaline aqueous solutions can be aided by mixing with some types of anionic surfactants that contain phosphorous. However, there are often environmental objections to phosphorus containing cleaners. Surfactants containing amine groups, such as are used in some commercial product surfactant mixtures recommended for strongly alkaline cleaners, also can be environmentally undesirable.
DESCRIPTION OF THE INVENTION
OBJECTIONS OF THE INVENTION
One major objective of the invention is to provide an alkaline, if desired very strongly alkaline, aqueous cleaning composition and/or a surfactant combination therefor, with cleaning power at least as good as that achieved by conventional prior art compositions that utilize substantial amounts of phosphorus and/or nitrogen containing surfactants but with minimization of the amounts of phosphorus and/or nitrogen used in the compositions. Another concurrent or alternative objective is to provide alkaline aqueous cleaning compositions with better cleaning power than those of the prior art. Other objectives will appear from the description below.
GENERAL PRINCIPLES OF DESCRIPTION
Except in the claims and the operating examples, or where otherwise expressly indicated to the contrary, 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 and claims, unless expressly stated to the contrary: percent, “parts of”, and ratio values are by weight; 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, and does not necessarily preclude chemical interactions among the constituents of a mixture once mixed; specification of materials in ionic form implies the presence of sufficient counterions to produce electrical neutrality for the composition as a whole, and 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 the objects of the invention; and the term “mole” and its variations may be applied to ionic, chemically unstable neutral, or any other chemical species, whether actual or hypothetical, that is specified by the type(s) of atoms present and the number of each type of atom included in the unit defined, as well as to substances with well defined neutral molecules.
SUMMARY OF THE INVENTION
It has been found that a mixture of particular types of nonionic surfactants with a particular type of anionic organic material, both substantially free from any chemical elements other than carbon, hydrogen, and oxygen, can achieve good cleaning power with acceptably low foaming in moderately to strongly alkaline aqueous cleaning compositions and has sufficient solubility to permit formulation of stable one package liquid concentrates with more than 25% of total alkali metal hydroxide content.
DETAILED DESCRIPTION OF THE INVENTION, INCLUDING PREFERRED EMBODIMENTS
One preferred embodiment of the invention is an aqueous liquid composition that is suitable, as such, after dilution with water, or both as such and after dilution with water, for cleaning hard surfaces, particularly steel and galvanized steel surfaces. This composition comprises, preferably consists essentially of, or more preferably consists of, water and:
(A) an amount of a dissolved alkalinizing component;
(B) an amount of a dissolved component of organic material selected from the group consisting of molecules that contain, in each molecule, (i) at least one carboxyl or carboxylate moiety and (ii) a total of at least 10 carbon atoms; and
(C) an amount of a dissolved component of nonionic surfactants, exclusive of those that are part of any of the previously recited components, selected from molecules that each contain at least four —(CH
2
CH
2
O)— moieties, preferably joined to one another in a block;
and, optionally, one of more of the following components:
(D) an amount of a component of sequestering agent and/or chelating agent that is not part of any of the previously recited components; and
(E) an amount of a component of antifoam agent that is not part of any of the previously recited components.
Preferred alkalinizing agents for component (A) include ammonium, sodium, and potassium hydroxides, with the latter two more preferred. Both of these appear substantially equal in promoting cleaning. Sodium hydroxide is usually less expensive but also forms less soluble salts with almost any acidic material that might be added to the composition and/or is less tolerant of non-electrolytes in mutual aqueous solution with it, so that at least some potassium hydroxide is normally preferred for very strong concentrates according to the invention. In one specific preferred embodiment, only potassium and/or sodium hydroxide(s) are used for component (A).
Independently of other preferences, in a concentrate composition according to the invention, the amount of dissolve
Harper Stephen D.
Henkel Corporation
Jaeschke Wayne C.
Johnson Lance G.
Shah Mukund J.
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