US 2956951 A
Description (OCR text may contain errors)
WATER BASE LUBRICANT CONTAINING DIMETHYL SULFOXIDE Michael J. Furey, Berkeley Heights, NJ., assignor to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Filed Oct. 26, 1956, Ser. No. 618,434
4 Claims. (Cl. 252-48.2)
This invention relates to water-base lubricants. Particularly, it relates to a water-base lubricant wherein water has been thickened to a lubricating oil viscosity with an organic thickener and small amounts of an organic sulfoxide have been added to impart extreme pressure properties to the lubricant.
The water-base lubricants of the invention are nonflamrnable, inexpensive lubricants having high load-carrying ability. These lubricants may be used as cutting oils, hydraulic fluids, metal-working fluids, and as general purpose lubricants where operating temperatures are not excessive.
The lubricating compositions of this invention will comprise water which has been thickened to a lubricating oil viscosity with an ether cellulose and which contains an extreme pressure improving amount of a dialkyl sulfoxide.
The ether cellulose thickeners operable in this invention include the water soluble C to C alkyl cellulose ethers such as methyl cellulose, ethyl cellulose, propyl cellulose, butyl cellulose, etc., and which include the monoand di-alkyl cellulose ethers, mixtures thereof, and mixed ether celluloses such as methyl ethyl cellulose, methyl propyl cellulose, etc.
The dialkyl sulfoxides useful in the invention have the general formula:
wherein each R represents the same or different alkyl radicals, containing from 1 to 3 carbon atoms, i.e., methyl, ethyl and nand iso-propyl radicals. For example, the sulfoxide can be dimethyl sulfoxide, diethyl sulfoxide, methyl ethyl sulfoxide, etc.
The lubricant of this invention will comprise a major proportion of water and a thickening amount, such as 0.5 to 10 wt. percent, e.g., 1 to 5 wt. percent, of ether cellulose and an extreme pressure imparting amount of dialkyl sulfoxide, such as 0.5 to 5.0 wt. percent, e.g., 1.0 to 3.0 wt. percent of the sulfoxide.
The invention will be further understood by the following examples.
EXAMPLE I A lubricant containing 1.7 wt. percent of a dimethyl ether of cellulose (commercially available under the name of Methocel 400), 2 wt. percent of dimethyl sulfoxide and 96.3 wt. percent of water, was prepared as follows: The Methocel 400 was mixed with about onefifth of the required amount of water as hot water for about minutes. The remaining four-fifths of the water was then added as ice water and the mixture was stirred until smooth and homogeneous. The resultant fluid was clear and colorless. The viscosity of this base mixture at room temperature was approximately 260 centistokes,
States Patent ice . 2 which is similar in viscosity to an SAE 30 grade oil. The 2 wt. percent of dimethyl sulfoxide was then added to the methyl cellulose thickened water. The sulfoxide immediately dissolved and the resultant product remained clear and colorless.
The product of Example I was then evaluated for its load-carrying ability in an Almen machine (a steel pin rotating at 600 r.p.m. between two halves of a loaded bearing) with gradual loading at 10 second intervals until failure. The product was also tested in the Shell 4-ball E.P. lubricant test. The results of these tests are shown in the following table, along with comparative data for a typical mineral lubricating oil.
Table 1 LOAD-CARRYING PROPERTIES OF METHYL CELLULOSE 'gIglENED WATER CONTAINING DIMETHYL SULF- As seen from the above table, the methyl cellulose thickened water had very little load-carrying ability in itself. However, upon the addition of 2 wt. percent of dimethyl sulfoxide, it was able to carry a total of 15 Almen weights before failure, and carried a load of 102 kg. in the 4-ball E.P. test. The typical lubricating oil carried a maximum of only 3 Weights in the Almen test and a 45 kg. load in the 4-ball test, thus illustrating the very high load-carrying ability of the water-base lubricant of the invention.
Other water-soluble additives may also be added to the composition, such as dyes, corrosion-inhibitors, metal deactivators, wetting agents, supplementary anti-friction or anti-wear additives, and bacteriostatic agents.
What is claimed is:
l. A water-base lubricant composition comprising a major proportion of water, 1 to 5 wt. percent of a water soluble ether cellulose thickener and l to 3 Wt. percent of a dialkyl sulfoxide having in the range of 1 to 3 carbon atoms in each alkyl group, wherein said lubricant composition is a clear solution.
2. A water-base lubricant composition comprising about to 99 wt. percent water, about 0.5 to 10.0 Wt. percent of a water soluble C to C alkyl ether cellulose thickener and about 0.5 to 5.0 wt. percent of a watersoluble dialkyl sulfoxide having in the range of 1 to 3 carbon atoms in each alkyl group, wherein said lubricant composition is a clear solution.
3. A water-base lubricant composition according to claim 2 wherein said ether cellulose is a methyl cellulose and said dialkyl sulfoxide is dimethyl sulfoxide.
4. A process of lubricating relatively moving, contacting surfaces which comprises applying to said surfaces a lubricant consisting of water thickened to a lubricating viscosity with a water-soluble alkyl cellulose ether thickener, and containing about 0.5 to 5.0 wt. percent of a water-soluble dialkyl sulfoxide having in the range or 1 to 3 carbonatoms in each alkyl group, wherein said lubricant is a clear solution.
References Cited in the file of this patent UNITED STATES PATENTS 4 Modl Nov. 14, 1944 Rogers et a1 June 28, 1949 Rogers et a1. .2; Dec. 12, 1950 McBride Nov. 25, 1952 Sullivan et a1. Dec. 31, 1957 OTHER REFERENCES Bastian: Metal Working Lubricants, McGraw-Hill, N.Y., 1951, pages 5 and 6.