US2390491A - Lubricant - Google Patents

Description

Q Patented Deall, 1945 2,390,491 wnmcm Harry '1. Bennett and Jerry R. Marshall, Tulsa, Okla, assignors to Mid-Continent Petroleum Corporation, Tulsa, Okla, a corporation of Delaware No Drawing. Application January 30, 1942,

Serial No. 428,867

2 Claims. (Cl. 252-486) This invention relates to lubricants and more particularly to the problem of inhibiting foaming therein. Objectionable foaming occurs when air is violently whipped into lubricants. An ordinary illustration of this condition appears in gear housings where the gears are only partially covered with oil so as to turn in an'oil-air sphere. Rapid rotation of the gears will then convert the lubricant into a foamy mass lacking the required lubricating properties. In addition to the various objections arising from insufficient lubrication, the volume of the lubricant is very greatly increased, and portions of the foam may be forcibly discharged from the housing. Therefore, excessive foaming may result in actual loss of valuable lubricant, while greatly impairing the lubricating value of the lubricant.

In commercial practice, the hazards and economic losses due to foaming lubricants are recognized as serious problems in this art, but it appears that such foaming has been regarded as an inevitable result of violently whipping air into the lubricant. The usual high grade lubricants, deliberately prepared to meet the special requirements for gear oils, are subject to'objectionable foaming. Our investigation of the prior lubricents in this art has failed to disclose any real I solution of these specific problems.

The present invention is a result of special study I and development work devoted to numerous conditions involved in this subject, the object being to create the cooperative conditions essential to a complete and entirely feasible solution of the old problem. Actual tests have shown that the in-- vention herein described will positively inhibit foaming in the lubricants. The tests show that we have successfully accomplished this outstanding result in a commercially feasible manner,

[ herein is intended to cover reactions which may result eitherin the formation of' true sulfonic .acids, sulfuric acid esters or both; it being understood that the nature of the resultant product depends largely upon the conditions and the materials which enter into the reaction. Thus the term su1fonated" is used generically to describe reaction products resulting from the use of sulfating and sulfonating agents.

Various products may be employed. However, we prefer to use an ester of sulfonated carboxylic acid such as the reaction product of the acyl esters of ricinoleic acid or of oleic acid, an unsaturated carboxylic acid, or of 12 hydroxy-ste'aric acid or other carboxylic acids containing a double bond or hydroxyl group or both when reacted with an energetic sulfonating agent as oleum, chlorosulfonic acid or sulfuric acid ester as butyl sulfuric acid in the presence of a group protecting agent as acetic anhydride. Various combinations of the above reagents may be used, or one may use other reagents known to the art.

However, the resulting product that is pref ferred is an acyl ester of a sulfonated carboxylic acid having more than 10 carbon atoms in the acid group and containing not mOre than 12 car- 'bon atoms in the acyl group. Esterification may 7 be in the sulfo group, the carboxyl group, the

whipped into the lubricant. In actual practice,

we have found that the quantity of'the selected ester may be very small, for example, less than 1%. and preferably less than 0.1%, of the lubricant. We will hereinafter refer to a specific exfoaming in certain petroleum oils which would that the invention is not limited to the popular have otherwise been subjected to very excessive foaming. However, it is to be understood that similar results are obtainable when the foam inhibitors are incorporated in other lubricants, and

chine known as a Mix Master" having rotary Example 1 Volume of lubricant mm gg figafi Lubricating stock Before Alter 16 minto minagitation agitation utes utes i B. A. E. 140 extreme presc. c. c. c. c'. c. c. 0.

sure gear lubricant"... 500 1,000 980 850 Above lubricant containin 0.05% (am inhibi or 600 540 500 e00 Example 2 v Volume oi agitated. Volume of mbncam mixture after settling Lubricating ntock Before Alter min- 60 minagitation agitation utes utes c. c. c. c. e. c. c. c. S. A. E. 60 aeroplane oil. 875 825 600 Above lubricant contsining 0.05% foam inhibitor 500 525 500 500 If desired the selected ester may be blended with a solvent in order to incorporate the ester in the oil. In such case the solvent may be an organic or an inorganic solvent and the one selected would depend upon its solvent value in the ester of sulfonated carboxylic acid and also its solvent value in lubricating oil.

It was found that a-small quantity,,less than 10%, 0t amyl acetate had the desirable solvent properties and could be used as the solvent. However, the use of amyl acetate is given here only as a specific example and is not intended to limit the use of solvents to this specific solvent, nor to this type of solvents, because other solvents known to the art possess the same valuable solvent properties.

Finally, it was found that when water was present, as is often the case inside of gear housings, caused by the condensation of moisture from the air, that the foaming tendency of the oil was not increased by the presence of water when an acyl ester of sulfonated carboxylic acid is used' to reduce foam formation, butin some cases the action of the foam reducing agent is increased in the presence of very small amounts of water.

It is, however, not to be construed that any solvent is necessary since an acyl ester of sulfonated carboxylic acid as indicated will act as a foam reducing agent in the absence of all sol vents. The solvent merely facilitates the incorporating of the foam-inhibiting agent in the oil.

We claim:

1. A lubricant comprising a petroleum lubricating oil wherein foaming is inhibited by an acctyl ester of a sulfonated rlcinoleic acid disinhibitor consisting of an acetyl ester of sulfonated ricinoleic acid, the quantity of said ester being less than .1% of the lubricant but suflicient to inhibit foaming of said lubricant.

HARRY T. BENNETT. JERRY R. MARSHAIL.