Rust inhibiting composition

Patented Mar. 17, 1953

2,631,979

UNITED STATES PATENT OFFICE

2,631,979

RUST INHIBITING COMPOSITION

John P. McDermott, Roselle, N. J., assignor to Standard Oil Development Company, a corporation of Delaware

No Drawing. Application August 30,1950, Serial No. 182,420

Claim.

. 1 .

This invention relates to rust preventing oil compositions and more particularly to mineral lubricating oil compositions which tend to inhibit rusting and corrosion of metal parts which are exposed to moisture.

A primary object of the present invention is the preparation of compositions which may be employed as internal combustion engine lubricants and which will also serve for protection of exposed surfaces of such engines when the same are not in use. When operating engines in climates having a high humidity, rusting begins within a very short period of time after the engine is shut down. The compositions of the present invention are particularly valuable in preventing such rusting and they are useful not only in the lubrication of internal combustion engines, but with oil bases of suitable viscosity they may be employed as turbine oils or as lubricants for fire arms, ordnance equipment, industrial machinery, etc., and for any lubricating purposes where metal surfaces are exposed to humid air. The compounds may also be added to other mineral oil bases and employed in motor fuels, emulsions, hydrocarbon polymers, polishes, paints, sprays, and the like.

The compositions of the present invention consist essentially of a hydrocarbon oil solvent containing dissolved therein polymerized linoleic acid. Linoleic acid may be polymerized by heating at a temperature of 330-360° C. in the presence of a small amount of water or in an atmosphere of steam for a period of 3 to 8 hours at pressures varying between 85 and 400 lbs. per sq. in. The resulting product consists essentially of the dimer, but minor proportions of the trimer are also formed. Methods for carrying out this procedure in detail may be found in the article by Charles G. Goebel, Journal of the American Oil Chemists Society, vol. 24, pp. 65-8 (1947). The dimer is of particular interest in connection with the present invention. This is believed to have the formula—

CH;(CHi)s- CH— CH— CH=CH(CH_I)tCOOH

CHi(CHi)s- CH CH— (CHahCOOH \h=CH (CL 252—57) etc., and in lubricating oils containing other additives such as detergents, pour depressants, thickeners, extreme pressure agents, other rust inhibitors such as degras, petroleum sulfonates, 5 pentaerythritol monooleate, lauryl mercapto acetic acid, sorbitan oleate, and the like. In the preparation of plastic type products, cut-back asphalts, microcrystalline waxes, synthetic waxes, and the like are included in the formulation. 10 Concentrations of the polymer in hydrocarbon solvents may vary from 0.025 to 5%, although concentrations of 1 to 2% are more generally preferred, especially when the composition is a mineral lubricating oil.

in the examples below are given detailed descriptions of laboratory tests which were applied to determine the effectiveness of compositions of the present invention, but it is to be understood that these examples are given for illustrative 20 purposes and are not to be construed as limiting the scope of the invention in any way.

Example 1

Compositions were prepared by dissolving 1% 25 and 2% by weight, respectively, of polymerized linoleic acid (consisting of 85% dimer, 12% trimer, and 3% monomer) in a lubricating oil base stock consisting of a conventionally refined Coastal naphthenic oil of 40 seconds viscosity (Saybolt) at ?10° F. These blends and a sample ³⁰ of the unblended base stock were submitted to a humidity cabinet test to determine the degree to which the oils prevent the rusting of a steel surface in a warm humid atmosphere. This test was conducted by dipping panels of 1020 cold ³⁵ rolled steel, 2” x 4 in size, in the oil samples and hanging them in an AN-H-31 humidity cabinet maintained at a temperature of 120 ± 2° F., the panels being surrounded by air of 100% humidity. Failure under this test is considered to take place ⁴⁰ when rusting occurs to an extent greater than three rust spots, no one of which is greater than 1 mm. in diameter. Results are shown in the following table:

Oil Composition 1°

The linoleic acid polymer may be advantageously employed as the active rust preventing ingredient in any hydrocarbon solvent, especially of the petroleum hydrocarbon type, and such solvent oils may, for example, be naphthas, spindle oils, light and heavy lubricating oil fractions, etc., and may be used when other ingredients are present such as in greases, sprays, paints,

Base oiL—____________________________________________

Base oil+1% polymerized linoleic acid_________________

Base oil-j-2% polymerized linoleic acid.................

216 600 ¹ Average of duplicate panels.

Example 2

A turbine oil composition was prepared by dis2,631,979 solving 0.1% by weight of polymerized linoleic acid (composition as in Example 1) in a solvent extracted Mid-continent lubricating oil fraction of 150 seconds (Saybolt) viscosity at 100° F. Samples of this composition and of the unblend- 5 ed base oil were submitted to the standard ASTM turbine oil rust test, designation DGG5-47T, using the procedure prescribed for distilled water. The procedure, in brief, is carried out as follows: 350 ml. of the oil sample is placed in a beaker and , 10. the beaker is placed in an oil bath maintained, at 140° F. A cold rolled steel specimen of cylindrical shape, one-half inch tin diameter and.5,%; inches long is suspended in-the oil.: Then 50 ml.

of the oil is removed and 30 ml. of distilled water 15 added. The oil and water are stirred together for 24 hours, after which the condition of the steel specimen was observed.

The results of the tests carried out as described above were as follows: 20

<td> Oil Composition</td><td> Amount of Rusting ;</td>

<td> Base-oil··__________________________________________ Base oil+,0.1% polymerized linoleic acid..______</td><td> Heavy rusting. 25 No rusting.</td>