US2393797A

US2393797A - High-temperature greases

Info

Publication number: US2393797A
Application number: US484861A
Authority: US
Inventors: John D Morgan
Original assignee: Cities Service Oil Co
Current assignee: Cities Service Oil Co
Priority date: 1943-04-28
Filing date: 1943-04-28
Publication date: 1946-01-29
Anticipated expiration: 1963-01-29

Description

I Patented Jan. 29, 1946 HIGH-TEMPERATURE GREASES John D. Morgan,"Southrange, N. J., assignor to Cities Service Oil Company, New York, N. Y., a corporation of Pennsylvania No Drawing. Application April 28, 1943, Serial No. 484,861

9 Claims. (or. 252-36) This invention relates to improvements in reases for high temperature use, and more particularly to such greases containing large proportions of petrolatum,

A variety of petrolatums have been used in the manufacture of lubricating greases, but as far as known they have constituted relatively minor proportions of the grease. In the manufacture of greases suitable for high temperature use or greases having a relatively low penetration, it has almost invariably been necessary to employ high percentages of soaps. For example, it appears from published data that a soap content of from 25% to 30% is necessary in order to provide a grease with a penetration of about 140. Only about half that amount of soap is used in the greases of this invention. l

In accordance with the present invention, it has been discovered that an excellent high temperature grease may be made from a moderate proportion of lithium stearate in petrolatum. This was an unexpected result because previous work had shown that a grease could not be made from Pennsylvania type oils and lithium stearate alone. A similar difliculty had been previously experienced in attempts to make greases from sodium soaps and Pennsylvania oils, which are classed as oils of low polarit (Klemgard Lubricating Greases, 1937, pages 362 to 363). Petrolatums are regarded as extremely nonpolar, but excellent dispersions of lithium soap inv petrolatum have been secured by the practice of the present invention.

The manufacture of greases in accordance with this invention'maybe illustrated by reference to the following example in which the quantities of the various ingredients are given in percentages by weight.

A grease having a penetration of140 (worked A. S. T. M.) was prepared by melting and intimately mixing 11% by weight of lithium stearate, 2.2% by weight of aluminum stearate, 0.5% by weight of tributyl phosphite and 76.3% by weight of green petrolatum. The tributyl phosphiteis used as an antioxidant. This grease in addition to having the penetration indicated, had-a dropping point of 370 F. The grease furthermore stood theseven-hour test in the Navy beater testing apparatus in which a bearing, is rotated under forced circulation at 3600 revolutions per minute while the grease is heated to a temperalatum grease was free of glycerine, and in fact a substantially pure product made from lithum carbonate and stearic acid. The petrolatum used may be refined instead of the crude product.

ture of 350 F. At the end of this test the grease I was still in good condition and was superior to v knowncommercial greases,

The lithium stearate used in making the petro- The more refined and whiter the petrolatum, the lighter color is the resulting grease. Greases made in accordance with the present invention may be made from somewhat variable quantities of stearate or otherlithium soap and aluminum stearate or other aluminum soap, the balance of the grease in each case consisting essentially of petrolatum. The proportion of lithium soap may vary from about 8% to 14%, while the proportion of aluminum soap may vary from 1.5% to 4%, the higher proportions of aluminum soap being used with the higher proportions of lithium soap. Greases made in accordance with the present, invention are preferably made without the use of mineral or other oils.

A softer grease than the penetration grease described above may be made by including from 1% to 4% of a lead or a silver soap, for example the oleates. The inclusion of 2% of lead oleate in the composition described above raises the penetration to about 240, and gives a grease which still has the high temperature characteristics. The use of this additional soap seems to give an effect different from that normally expected since it is generally found that the larger the proportion of soap, the lower the penetration of the grease. The lead or silver soap in the percentage range referred to, maybe used in the making of other specific greases containing different proportions of lithium soap or in making greases containing lithium soap and aluminum soap in the range of proportions referred to above. The aluminum soap seems to aid in dispersing the lithium soap in the petrolatum.

Antioxidants such as tributyl phosphites, are not essential to the production of a good grease in accordance {with the present invention, but such an antioxidant is preferably employed to aid in prolonging the life of the grease and to inhibit oxidation and corrosion. Other known inhibitors may be employed such as other alkyl phosphites, aryl phosphites and amino compounds.

Although the features of the invention have been described and'illustrated in accordance with certain specific examples, it is to be understood thatithe invention is not to belimited thereto or otherwise be restricted, except by the prior art and the'scop'e of theappended claims.

Having described the invention and illustrated 1. A high temperaturegrease comprising approximately 11 by weight of lithium soap. 2.2%-

by weight of aluminum soap, the remainder being essentially petrolatum. 1 X

2. A high tempera e lubricant having an A. S. T. M. penetration of about 140 and consisting essentially otirom'8% to 14% by weiaht of lithium stearate, from 1.5% to 4% of aluminum stearate, the remainder-of the lubricant being composed essentially of petrolatum.

3. A high temperature grease consisting of petrolatum having dispersed therein from about 8% to about 14% by weight of a lithium soap based on the weight of the grease. v

4. A high temperature relatively hard grease consisting essentially of petrolatum, from 8% to about 14% by weight of a lithium soap; and from, 1% to 4% by weight of a soap having a softening effect on the grease and selected from the group consisting of lead and silver soaps. A

5. A high temperature grease comprising approximately 11% by weight of lithium stearate,

ap r xim tely 22% y w ight of aluminum m ate, approximately --'0.5% by weight of an antioxidant, and approximately 76.3% by weight of petrolatum. 6.Agreaseasdeilnedbyclaimfiwhichineludes a, relatively smallproportion of a soap selected from the silversoal s- 7. A lubricant consisting of a petrolatum which is dispersed approximately 11% byweight v of a lithium soap based on the weight of the grease and a dispersion medium comprising an aluminum soap.

group consisting of lead and