Cleaning and liquid contact with solids – Processes – Using sequentially applied treating agents
Reexamination Certificate
2001-04-11
2003-02-25
Lovering, Richard D. (Department: 1712)
Cleaning and liquid contact with solids
Processes
Using sequentially applied treating agents
C134S026000, C508S530000, C508S532000, C510S264000, C510S266000, C516S072000, C516S076000
Reexamination Certificate
active
06524396
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to metal machining and involves mechanical cutting of metal, followed by cleansing and/or anticorrosion treatment. A ‘metal cutting’ procedure is to be understood to be a process in which the shape of a metal item is altered by removing material from the piece being machined with a machining tool. Examples of such a metal cutting procedure are drilling turning, milling and grinding. During these processes, the tool and the piece being machined have to be washed with a liquid cooling lubricant (cutting compound). This serves to lubricate the tool in order to avoid welding and overheating, to dissipate the heat being produced and to remove the turnings or other metal particles which are produced. The cutting compound has to be formulated in such a way that it prevents corrosion of the piece being machined.
BACKGROUND OF THE INVENTION
Cutting compounds which are known for use in engineering include oils, oil-in-water emulsions or water-dissolved, cutting compounds which consist only of an aqueous solution. In the present invention, oil-in-water emulsions and water-miscible concentrates thereof, that is cutting compounds which contain an oil component are considered.
In the processing sequence for a metallic item, the item is generally cleansed and/or protected against corrosion after a cutting procedure. Cleansing should remove in particular residues of the cutting compound, but also other soiling and any metal particles which are still adhering to the item. Hitherto, the choice of cleanser has only been affected by the nature of the cutting compound used during metal machining prior to the cleansing step insofar: as the cleanser has to remove the lubricant. All the constituents of the cutting compound represent ‘contaminants’ for the cleanser, which render the cleanser unusable: after a period of time. Depending on the degree of contamination with cutting compound, the cleanser either has to be topped-up with fresh cleansing-active components, file liquid bath has to be regenerated or the batch discarded and a new batch prepared. This leads to a high consumption of cleanser-active substances which have to be disposed of at the end of their useful life. This involves environmental pollution and Is also economically disadvantageous due to the amount of material consumed.
BRIEF DESCRIPTION OF THE INVENTION
The present invention provides a combination of an agent and a process for metal cutting procedures which makes use of a water-mixed cutting compound, followed by cleansing and/or corrosion protection of the metal part being processed with an aqueous cleansing/anticorrosion agent in which the constituents of the cutting compound and the aqueous cleansing/anticorrosion agent are mutually adjusted in such a way that the constituents of the cutting compound augment, or at least do not impair, the cleansing/anticorrosion agent. With this system, the cutting compound is not a ‘contaminant’ in the cleansing/anticorrosion agent, rather it adds to the effectiveness of the latter. This means that smaller amounts of active substances have to be used for the cleansing/anticorrosion agent itself. The service time of the cleansing/anticorrosion agent is also extended without having to recondition the bath. The use of smaller amounts of substances and lower waste Disposal costs protect the environment and make the entire process cheaper.
A first embodiment of the present invention relates to a combination of agents consisting of a first agent for metal cutting procedures and a second agent for subsequent cleansing and/or anticorrosion treatment, characterised in that the first and second agent contain:
(i) an emulsifier system consisting of:
(a) ethoxylates/propoxylates of fatty alcohols having 8 to 18 carbon atoms in the alcohol, which contains 2 to 6 ethylene oxide units and 4,to 8 propylene oxide units;
and
(b) fatty alcohols and/or fatty alcohol propoxylates having 12 to 24 carbon atoms in the alcohol and 0 to 3 propylene oxide units and/or distillation residues of such fatty alcohols;
in a ratio, by weight, a:b=1:0.2 to 0.2:1;
and
(ii) corrosion inhibitors;
wherein the first agent also contains an oil component.
The emulsifier system used according to the present invention is known from German Patent Application DE-A-197 03 083. Compared with conventional emulsifier systems, it has the advantage that it tends to form only very little foam in soft to moderately hard water, that is in water having, less than 12°, and in particular less than 8°, dH.
DETAILED DESCRIPTION OF THE INVENTION
Strict requirements are thus solaced on the composition of the emulsifier system and the molecular structure of the emulsifiers used. In the first instance, according to (a), fatty alcohol ethoxylates/propoxylates have to be present which contain 2 to 6 ethylene oxide units and also 4 to 8 propylene oxide units. These hydrophilic components have to be combined with the hydrophobic components (b), non-alkoxylated fatty alcohols having 12 to 24 carbon atoms, distillation residues thereof or alkoxylation products thereof having up to, on average, at most 3 propylene oxide units. Furthermore, the approximate ratio, by weight, which is given above must be observed. Distillation residues of fatty alcohols having 12 to 24 carbon atoms are obtainable from Henkel KGaA, Düsseldorf, under the name Pernil® RU.
Non-polar or polar oils of petrochemical or natural origin may be used as the oil component in the first agent. Synthetic oil components are also suitable. Examples of oil components which may be us,ed are paraffinic or naphthenic mineral oil, dialkylethers having 12 to 20 carbon atom.,t and ester oils. The ester oils may be of plant or animal origin and are available as esters of glycerine with three fatty acids (so-called fatty acid triglycerides). One example of this type of ester oil is rape seed oil. Such ester oils may also be obtained synthetically by esterifying glycerine using selected fatty acids or by transesterifying naturally occurring fats and oils using other fatty acids.
The corrosion inhibitors which are used according to the present invention in the aqueous cutting compound and also in the aqueous cleansing/anticorrosion agent and in each of the concentrates thereof are preferably selected from alkanolamines and/or from branched or unbranched, saturated or unsaturated aliphatic mono- or di-carboxylic acids having 6 to 10 carbon atom and/or from aromatic carboxylic acids having 7 to 10 carbon atoms, wherein the carboxylic acids are present partially or completely as salts. When alkanolamines and salts of carboxylic acids are mentioned, this may mean, on the one hand, that the alkanolamine salts of the carboxylic acids are used directly. This is equivalent to a mixture of alkanolamines and carboxylic acids which react with each other to form salts. On the other hand, the alkanolamines may be used as such and the carboxylic acids may be us d as alkali metal salts, preferably as potassium salts. Mixtures of carboxylic acids; and alkali metal hydroxides are equivalent to the alkali metal salts of carboxylic acids. Depending on the pH of the ready-to-use water-mixed cutting compound or the aqueous cleansing/anticorrosion agent, the alkanolamines and/or carboxylic acids are present as equilibrium mixtures consisting of neutral molecules and cations in the case of alkanolamines or anions in the case of carboxylic acids.
The first agent (the cutting compound or its concentrate) and the second agent (the cleansing/anticorrosion agent or its concentrate) may contain the same corrosion inhibitors. However, this is not necessary. It simply has to be ensured that the first agent and also the second agent each contain one or more of the previously-mentioned corrosion inhibitors. However, it is preferable if the first agent contains one or more corrosion inhibitors which are, also present in the second agent. If both agents in ready-to-use form are present during continuous operation, the combination of corrosion inhibitors, which is present in the first
Geke Juergen
Johansson Anders
Oelscher Hans-Peter
Harper Stephen D.
Henkel Kommanditgesellschaft aut Aktien
Lovering Richard D.
Ortiz Daniel S.
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