US2359738A - Rust-preventive compositions - Google Patents

Description

Patented Oot..10, 1944 RUST-PREVENTIVE COMPGSITIONS Knspel F. Schiermeier, Alton, Ill, assignor to Shell Development Company, San Francisco, Calif., a corporation of Delaware No Drawing. Application February 16, 1943, Serial No. 476,119

11 Claims. 252-43) This invention relates to new and improved rust preventive oils and greases. It is particularly pertains to solution-stable hydrocarbon compositions containing sulfated castor oil, which mixture affords a high degree of protection against rusting.

It is the purpose of the present invention to produce highly efl'ective rust retarding compositions. Another object is to create a solutionstable, substantially anhydrous, lubricating oil composition containing sulfated castor oil. A further purpose is to produce a lubricating grease which has greater resistance to corrosion than normal greases. Another object is to provide a concentrate which may be blended with a mineral oil or grease to impart anti-rusting properties to the resulting substantially water-free mixture. Other purposes will be apparent from the following description.

Sulfated castor oil (popularly known as sulfonated castor oil, Turkey red oil) is very effective as a rust retarding agent. Although commercial sulfated castor oil has been used in oilwater emulsions and as an anti-rusting agent in aqueous media such as anti-freeze solutions, its low solubility in non-aqueous petroleum compositions and poor solution stability in such blends have hitherto made quite impractical the utilization of such a'substance in substantially anhydrous oils or greases.

According to the present invention, however, it has been found that solution-stable oils and greases can be produced, which oils and greases contain sulfated castor oil in corrosion-preventive quantities, by the following expedient. Commercially available suli'ated castor oil is first dehydrated and the dehydrated product is then blended with mineral oil, together with at least one, and preferably two, solutizers. The required solutizer is a normally liquid fatty acid having at least 10 carbon atoms, while the auxiliary or optional solutizer is a polar solvent which is substantially completely miscible with the mineral oil at room temperature and has a solubility in water of at least This auxiliary solvent should also be substantially neutral, that is, having an ionization constant between about and 10".

Commerciall available Turkey red oils normally contain considerable amounts of water of the order of about They may be dehydrated by heating, say by heating to 275 F. with vigorous agitation. The water content of the product, as well as the starting material, may be conveniently determined by refluxing with toluol and collecting the aqueous distillate. When the water content of the dehydrated product has been reduced to about 0.5% or lower, it is suitable for my purpose. While the dehydrated sulfated castor oil may be incorporated in the lubricant as such, I prefer to use its ammonia alkali metal or alkaline earth metal salts.

Of the normally liquid fatty acids, oleic acid is particularly effective as a solutizer for the dehydrated sulfated castor oil. Other solutizers which may be similarly employed are ricinolelc, undecylenic. linoleic, fish oil fatty acids, partially hydrogenated fish oil fatty acids, and the like. These compounds may also contain such elements as chlorine, sulfur, phosphorous, etc., part cularly if a rust preventive extreme pressure lubricant is desired.

quired solubility comprise the C4 to Ca monohydrlc alcohols; esters, ethers and ketones such as butyl carbitol, amyl carbitol, hexyl carbitol, diacetone alcohol, cyclohexanone; ethyl, butyl, propyl and amyl acetates, di-isopropyl and di- 1 ethyl ether, dioxane, butyl and amyl Cellosolve,

acetal, etc. Pyridine may also be used.

Although the sulfated castor oil .may be incorporated in the hydrocarbon composition by means of the principal solvent alone, the use of the auxiliary solvents allows a greater amount of the sulfated castor oil to be utilized and produces a more homogeneous and more stable blend.

Amounts of sulfated castor oil required to impart anti-corrosive properties to various hydrocarbon lubricants may vary between about 0.1% and 5% w. and preferably about 0.5-3.0% w. The principal solvent (liquid fatty acid) may be present in amounts from about 0.3%-10% w., while the auxiliary solvent is present up to about 1.5% w. The total amount of the one or more solubilizers should be at least equal to and should preferably be from about 1 to 2 times the amount by weight of the sulfated castor oil, with the primary solutizer present to at least twice the amount of the auxiliary solvent.

An amount of solutizers less than the above minimum may result in a temporarily homogeneous mixture which, however, is not storagestable and may separate in the course of days,

weeks or months. An excess of the fatty acid such as oleic acid, on the other' hand, may interfere with the rust-protective properties of the oil and in the case of greases may cause undue liquification of the grease.

In producing the oils of this invention, a concentrate of these three ingredients may be compounded having, for example, from about 10% w. to about 70% w. dehydrated sulfated castor oil, about 30% w. to about 90% w. of the principalsolubilizing agent and a few per cent, if any (i. e. up to about 15% w.), of the auxiliary solubilizing agent provided the ratio of solutizer to sulfated castor oil is not below about 1. This concentrate may be dissolved in a refined, mineral lubricating oil to impart rust retarding properties to the resulting mixture. In some instances, upon blending the mineral oil with the concentrate, a light, fiocculent precipitate may appear. It is probably due to the presence of a small amount of more highly sulfated castor oil molecules which are insoluble in petroleiun. It may either be filtered, or allowed to settle and the clear oil decanted. The resultant blend is then solution-stable over a long period of time.

If desired, the concentrate may first be dissolved in a relatively small quantity of mineral oil to produce a blend which is filtered, and the filtered blend is then further diluted with mineral oil to produce the rust-proofing oils of this invention.

As an example of my invention, a concentrate consisting of 40% w. sodium salt of dehydrated sulfated castor oil, 55% w. oleic acid and w. normal amyl alcohol was made up. Since the original sulfated castor oil contained about 25% water, this was dehydrated by heating to 275 F. with vigorous agitation. The dehydrated sulfated castor oil salt was then mixed with the oleic acid at 250 F. The mixture was allowed to cool somewhat, and the alcohol was added and thoroughly mixed to produce the finished concentrate. 3% w. of this rust retarding concentrate was then blended at 100 to 150 F., with a highly refined lubricating oil and the resulting slight precipitate was eliminated by filtration.

To 'test the ei'llcacy of this lubricating oil mixture, steel strips were dipped in-it for minutes, allowed to drain for 10 minutes, and then placed in a, humidity cabinet at 100 F. which contained water-vapor saturated air continuously changing at the rate of about 1 to 1 times an hour. These strips were observed for signs of rusting for a continuous period of over 200 hours. Perfect rust protection was afforded them throughout the trial.

The ingredients of my rust retarding concentrate may also be incorporated into lubricating greases to produce consistent or plastic corrosion retarding greases. Greases to which these ingredients may be added comprise in particular may also effectively be used, but in decreased rust retarding effect.

Plastic greases contain as a rule between about 5% to 50% soap, and usually between about 10% to 26%. Thus, as another example of the present invention, the above concentrate consisting of 40% w. suifated castor oil, w. oleic acid and 5% w. n-amyl alcohol was incorporated in an amount of 3% w. in a lubricating grease having an initial penetration of 130 to 160 and a calcium soap content of 20 to 24% w. In a humidity cabinet test of over 500 hours, the same grease which lacked this concentrate allowed moderate rusting, while the grease containing the present concentrate afforded perfect rust protection to the metal surface. Although this concentrate may be added in amounts greater than about 3% w., relatively larger amounts tend to liquefy this particular grease.

This protection of lubricated or working metal parts against rusting or corrosion obviously has many applications. Corrosion not only has a deleterious effect upon the metal surfaces, but

general with also frequently loosens finely divided metal oxides which may act as oxidation catalysts increasing the rate of deterioration of various organic compounds with which they come in contact, or again they may enter between moving parts of machinery where they act as abrasives.

Although the treatment of the present invention is applicable to various metals, it is particularly eilicacious as applied to steel surfaces or surfaces containing other ferrous metals. For example, it is particularly desirable to protect the surfaces of steel machine parts such as gears and the like, parts of internal combustion engines such as cylinder walls and piston rings, and

other machine parts normally subject to corrosion prior to use and to wear during use. Also when an element or radical possessing or contributing to extreme pressure load-bearing propertiesfor example, S, Cl, P, etc-is present in. my rust preventive composition, the resulting metal surface coating is particularly resistant to abrasion and seizing. Such a coating is of especial benefit in the case of steel bearing surfaces of engines, high load carrying gears such as hypoid gears and various other mechanisms.

My lubricating oil or grease containing the above-described components may similarly be employed advantageously to protect-non-working or stationary metallic surfaces, particularly the polyvalent metal soap greases, e. g. Mg, Ca,,

Ba, Al, etc. soap greases, although they may also causing liquefaction of the grease than for a low 1 soap content grease.

Lesser amounts than 2% those containing iron, against the hazard of corrosion in the presence of water (including alkaline orsea water). To illustrate: Moisture readiLy attacks finished or semi-finished metal ob- Jects unless the metal surface is covered during storage or shipment by a protective coating such as a slushing oil; water in diesel engine fuels often corrodes closely fitted parts such as are found in diesel engine unit type injectors; water in turbines corrodes turbine lubricant circulatory systems, particularly the governor mechanisms of steam turbines; and water in hydrocarbon oils, such as gasoline, rusts steel storage tanks and drums.

However, the anti-corrosive protection afforded by my compositions is not limited to those metallic surfaces with which the solvent vehicle isin continued contact. Metal parts may gain a uniform protective coating by being dipped into, sprayed with, heated in contact with, or otherwise treated with my rust retarding lubricants to condition the metal surface with rust resistant properties which properties remain in appreciable degree long after the oil or grease film has substantially completely disappeared. Also such protective oil film may be longer perpetuated by the application of paint orother siccative coating to the treated metal surface. This treatment is particularly adapted to the rust proofing of pipes and other metallic vessels or conduits as well as to exposed metal surfaces such as bridge structures, auto bodies, etc. Or again, my rust retarding oil may be used as a quenching oil to impart unusual surface resistant qualities to the metal treated, the heated metallic (in particular, ferrous) article being immersed in the cooler oil.

I claim as my invention:

1. A homogeneous, storage-stable, substantially anhydrous rust-retarding lubricant comprising predominantly a mineral lubricating oil containing from 0.1% to w. of a compound selected from the group consisting of dehydrated sulfated castor oil and theammonia alkali metal and alkaline earth metal salts thereof, together with a normally liquid fatty acid having at least carbon atoms in an amount at least equal to that of said compound.

2. The composition of claim 1 in which the oastor oil compound is present in an amount of 0.53% w.

3. The composition ofclaim 1 in which the fatty acid is oleic acid.

4. A homogeneous, storage-stable, substantially anhydrous rust-retarding lubricant comprising predominantly a mineral lubricating oil containing from 0.1% to 5% w. of a compound selected from the group consisting of dehydrated sulfated castor oil, and the ammonia alkali metal and alkaline earth metal salts thereof, together with two solubilizers, one being a normally liquid fatty acid having at least 10 carbon atoms, and the other a substantially neutral polar solvent which is substantially completely miscible with the mineral lubricating oil at room temperature and has a solubility in water of at least 5%, the amount of said solubilizers being at least equal to that of said compound, and the amount of said fatty acid being at least twice that of said polar solvent.

5. The composition of claim 4 in which the fatty acid is oleic acid, and the polar solvent is n-amyl alcohol.

6. The composition of claim 4, wherein the amount of said solubilizers is between about 1 and 2 times that of said compound.

7. A homogeneous, storage-stable, substantially anhydrous rust-retarding lubricant comprising predominantly a hydrocarbon lubricating oil containing about 0.1% to 5% w. of a compolmd selected from the group consisting of dehydrated sulfated castor oil. and the ammonia, alkali metal to two times the amount of castor oil compound and the fatty acid being present in at least twice the amount of the alcohol.

8. A homogeneous, solution-stable, rust-retarding composition consisting essentially of substantially anhydrous mineral oil in which is incorpor;

ated about 0.1% w.'to 5% w. sodium salt of de-- hydrated sulfated castor oil, about 0.3 to 10% of oleic acid and not more than about 1.5% w. of an alcohol having from four to six carbon atoms, the total oleic acid and alcohol being present in between aboutone to-two times the amount of the castor oil salt with the oleic acid present in at least twice the amount of the alcohol'.

9. A rust-retarding calcium soap grease comprising essentially a substantially anhydrous mineral lubricating oil in which is incorporated an alkali metal salt of dehydrated sulfated castor oil, an oil-soluble normally liquid fatty acid and an alcohol having from one to six carbon atoms, said fatty acid and alcohol being present in between about one and two times the amount of the castor oil salt with the fatty acid present in at least twice the amount of the alcohol, the final concentration of these additives in the grease being between about 0.1% to 5% w. castor oil salt, about 0.3% to 10% w. fatty acid and not more than about 1.5% w. alcohol.

10. A normally plastic grease comprising predominantly a major proportion of substantially anhydrous mineral lubricating oil and a minor proportion of a soap, which grease contains an alkaline earth metal salt of dehydrated sulfated caster oil. an oil-soluble normall liquid fatty acid and an alcohol having from one to six carbon atoms, said fatty acid and alcohol being present in between about one and two times the amount of the castor oil salt with the fatty acid present in at least twice the amount of the a!- cohol, the final concentration of these additives in the grease being between about 0.1% to 5% w. castor oil salt, about 0.3% to 10% w. fatty acid and not more than about 1.5% w. alcohol,

11. A concentrate suitable for incorporation into hydrocarbon lubricants to impart anti-rusting properties thereto, the essential ingredients of which concentrate comprises sodium salt of dehydrated sulfated castor oil, oleic acid and n-amyl alcohol in a weight ratio of about 8:11:1.

marm- F. SCHIERMEIER.