US2554985A - Process for the protection of metals - Google Patents

Description

contact with the atmosphere.

Patented May 29, 1951 PROCESS FOR THE PROTECTION OF METALS Lucien Hemmer and Jean Balvay, Paris, France, assignors to Societe anonyme dite: Standard Francaise des Petroles, a corporation of France No Drawing. Application December 16, 1948, Serial No. 65,747. In France January 3, 1948 Claims.

This invention relates to the preparation of anti-corrosion preparations for protecting metal surfaces against corrosion and particularlyto prevent rusting of articles or surfaces of ferrous metals.

It is well known that the tendency to rust is one of the great disadvantages in the use of ferrous metal appliances, and that it is especially -so in humid climates and coastal areas because of the action of chlorine and other reactive materials contained in the atmosphere.

In order to protect metal surfaces from rust, it is usually sufficient to isolate them from all In order to do this, lubricating oils may be used. If two pieces of polished steel are taken and one of them immersed entirely in lubricating oil and the other is simply coated with a thin film of oil, e. g., by rubbing with a pad impregnated with lubricating oil, the plate entirely immersed is protected against rust for a very long time, while the plate which has simply been coated With a thin layer of oil becomes covered with rust after a very short exposure to the air.

The efficiency of the protection of coatings of this general type has been increased by mixing with mineral oils a petrolatum or a parafiin which gives a Vaseline-like product. The problem has not, however, been completely solved.

When a plate protected by a thin coating of oil, on which has been placed a few droplets of water, has been exposed to the air, at the end of a few days rust appears in the regions Where the droplets of oil were placed, even sometime after these have evaporated. This occurs because the films of oil are not strictly continuous,

in particul' r in the regions Where the drops of water were, which permits actual contact between the metal and the atmosphere. This is caused, in. fact, by a preferential displacement of water for oil on the surface of the metal, that is to say, the water has a greater afiinity for the metal surface than the oil and in time displaces the oil on the surface of the metal, at least in part.

In order to obtain an efficient protection of the metal, it is necessary to reverse these conditions and increase the affinity of the oil for the metal surface to a point where it displaces water.

The present inventors have discovered that there are two groups of compounds which, when mixed, are capable of producing the desired con ditions of preferential displacement of water by oil on the surface of the metal,

The first group of compounds comprises those which are soluble in the oils and insoluble in Water and which have also a great affinity for the metal surface. The compounds capable of fulfilling these conditions are:

(a) Natural fatty acids or synthetic fatty acids having more than 10 carbon atoms per molecule, sulfonated fatty acids or alcohols, naphthenic acids, sulfo-naphthenic acids, e. g., such as those obtained by the treatment of petroleum distillates with sulfuric acid, resinic acids (e. g., abietic acid, etc.) obtained from the distillation of wood, resinous or oily residues from paper manufacture, alkyl benzene or naphthalene, sulfonic acids obtained by synthesis, polyacids, such as adipic acid, sebacic acid, and the like.

Cresols extracted from wood tar, such as the thio-cresols, alkyl phenols, mercaptans, or compounds corresponding to the formula I-ISR, R being an aliphatic radical having more than 5 carbon atoms and which may be substituted in the organic radical of these products, may contain one or more of the substitution groups such as: O, OH, N, S, 00, CL, and the like.

(1)) Polyvalent metal salts of the above acids such as salts of lead, copper, iron, tin, zinc, manganese, mercury, and the like, are' better agents than the similar acids. These salts can be prepared by double decomposition or by direct action of the metal, or better still its oxide, with the difierent acids, phenols, thio-phenols or mercaptans (in general the basic salts react better than the acid salts).

(c) The ether salts corresponding to the acids indicated above, in particular, to ether salts of higher alcohols and most particularly, polyalcohols of natural, animal or vegetable origin, such as, suintine, lanoline, spermaceti oil, spermaceti wax, beeswax, Chinese wax, and the like, or of synthetic origin such as the ether salts of pentaerythritol, cholesterol, and the like.

((1) Amines and imines of higher molecular weight, having more than 6 carbon atoms in the molecule, and their salts with the organic acids mentioned above, such as heptadecylamine oleate, and the like, alkyl pyridine bases and their homologues, such as cetyl pyridine, and the like, and their salts with the organic acids indicated above, ammonium bases and pyridinium bases having more than 10 carbon atoms in the molecule, and their salts with the organic acids mentioned above.

The second group of compounds comprises compounds superficially active vis-a-vis the water by having a sufiicient solubility in the oil. The

inventors have discovered that these are generally salts of bases such as sodium, potassium, ammonium, lithium, calcium, quaternary ammonium bases, oxonium, urea and imines, and the like with:

1. The different acids mentioned above.

2. Cresols and phenols or naphthols, alkylated or not, and their corresponding thio compounds.

3. Mercaptans having more than 5 carbon atoms in the molecule.

The process according to the invention consists in mixing from 120% of any one or more of the many compounds of each of these two groups with a lubricating oil. In this manner there are obtained products possessing anti-rust properties greatly superior to those of the pure oils and equally superior to those obtained when using a mixture of the compounds of only one category. A plurality of compounds of each category may also be employed.

The comparative efiiciency was determined by the following method:

Metallic plates 3 x 10 centimeters were perfectly polished by mechanical means and coated with a thin film of the rust resisting oil product by total immersion in the oil product and pouring off the excess of the oil over a period of 6 hours. The plates thus covered with the oily protective coating were maintained in an etuve at 25 C. The true test of corrosion consists in immersing the plates for one hour in standardized synthetic sea water and then to expose to air for a constant temperature for one hour. This cycle is repeated for eight hours and finally the plates remain in contact with the air of the etuve for sixteen hours. The number of days necessary for each plate to be completely covered with rust is noted.

In order to explain more fully the present invention, the following examples are given but the invention obviously is not limited to them.

The use of a mixture of suintine (suint) and lanoline on the one hand and sulfonate of soda on the other hand, being already known, these are used for comparative purposes.

First series of emampZes.Using a single compound from one of the group:

Plate 100% Products Used rust at the end of- Spindle Oil y 1 Spindle Oil+5% lead sulionaphthenate... 10 Spindle Oil+5% suintine 2 Spindle Oil+10% sodium sulfonaphthenate. 2

Spindle il+10% triethanolaminc stearatc Sp ndle Oil+% triethanolamine stearate. Sp ndle Oil+5% triethanolamine suintate. Spindle Oil+5% ammonium chlorostearate Second series of ewamples.Using a mixture of one compound from each of the two groups mentioned:

Third series of examples.Use of a plurality of compounds from each of the two groups:

The oily base may comprise petroleum mineral oils or synthetic oils covering all ranges of viscosities from spindle oils (very light lubricating oils) up to cylinder oils. Mixtures of anti-rust oils, such as those obtained from petroleum or parafiin to obtain products of a Vaseline-like consistency may also be used which may, if desired, be'diluted with a solvent such as gasoline, white spirits, gas-oil, or other appropriate solvents.

Such mixtures can be utilized with advantage wherever it is necessary to preserve a surface of ferrous metal against rust.

In place of using a mineral oil as the oily base, a drying oil may also be used. In this manner, with the addition of pigments generally employed in paints, excellent anti-rust paints may be obtained.

Excellent industrial anti-rust oils, petrolatums, waxes, and ordinary or bituminous or tarry paints can thus be obtained by adding, during or after manufacture, mixtures of from 0.1 to 20% by weight, based on the total composition, of one or more of the compounds of each of the two groups mentioned above.

The invention has been described both in general terms and by way of specific examples. Various ingredients may be used and numerous modifications of detail conforming to the spirit thereof, can be effected without departure from the invention.

What is claimed is:

1. Composition according to claim 6 wherein said oily vehicle is a lubricating oil.

2. Composition according to claim 6 wherein said oily vehicle comprises petrolatum.

3. Composition according to claim 6 wherein said oily vehicle comprises a drying oil.

4. A corrosion inhibiting composition consist-.

ing essentially of a mineral oil base vehicle containing 0.1 to 20% by weight of a metal sulfonaphthenate.

5. Composition according to claim 4 wherein said oily vehicle is a lubricating oil.

6. A rust inhibiting composition consisting essentially of a mineral oil base vehicle containing 0.1 to 20% by weight of at least one metal sulfonaphthenate selected from the groups which consist of lead and sodium sulfonaphthenates and 0.1 to 20% of a material selected from the group which consists of lanoline and suintine.

7. A rust inhibiting composition consisting essentially of a light mineral base lubricating oil containing about 5% by weight of sodium sulfonaphthenate and about 10% by weight of suintine, based on the weight of the total composition.

8. A rust inhibiting composition consisting essentially of a light mineral base lubricating oil containing about 10% by weight, based on the total composition, of sodium sulfonaphthenate and abo 5 of lanoli e.

5 9. Compositmn according to claim 8 to which is added about 2.5% of lead naphthenate.

10. Composition according to claim 8 to which is added about 2.5% of lead sulfonaphthenate.

LUCIEN HEMMER. JEAN BALVAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Lebo Dec. 12, 1939 Rocchini Nov. 4, 1941 Irwin May 26, 1942 Farrington et a1 J an. 19, 1943 Cook et a1 Nov. 9, 1943 Sharp Apr. 17, 1945 Kollen Mar. 25, 1947

Claims (1)

1. 6. A RUST INHIBITING COMPOSITION CONSISTING ESSENTIALLY OF A MINERAL OIL BASE VEHICLE CONTAINING 0.1 TO 20% BY WEIGHT OF AT LEAST ONE METAL SULFONAPHTHENATE SELECTED FROM THE GROUPS WHICH CONSIST OF LEAD AND SODIUM SULFONAPHTHENATES AND 0.1 TO 20% OF A MATERIAL SELECTED FROM THE GROUP WHICH CONSISTS OF LANOLINE AND SUINTINE.