US2514311A - Process of manufacturing an aluminum base grease - Google Patents

Description

July .4, 1950 A. E. CALKINS PROCESS OF MANUFACTURING 4;: ALUMINUM BASE GREASE I Filed Dec. 8, 194a FL lEl DISI'ILLATE.

ALUMINUM SOAP ALUMINUM STEAIZATE) 4 Coolme To' 250-550" F.

NEuTRAL(F|N|sHEn) LUBRICATING Om NORMAL. FINISHING OPERATIONS QAPID COOLING To 'bETwEEN Acu: TIZEATMENT 5013A WASHING:

OVER NQOH EDISTILLATION Lu'bxzlcATme OIL. DISTILLATE. FROM OTHER OPEZATION'S' 'COOLED GREASE To PAcLAeEs CRYSE L ZATIQ IN PACKAGES SHIPMENT Gustav. E. Calida-s Ralph Glam. beer-bower @arle 159626 J w eg "Gina/enters Patented July 4, 1950 PROCESS OF MANUFACTURING AN ALUMINUM BASE GREASE Austin E. Calkins, Westfield, N. J.,, andRalph Barley, Glen Burnie, and Alan Beerbower, Baltimore, Md., assignors'to' Standard Oil Development Company, a corporation of Delaware Application December s, 1948, Serial Ne. 64,164

1 Claim. 1

The present invention relates to a process of preparing an aluminum basegrease. It relates more particularly to an aluminum soap thickened lubricating grease prepared with mineral base lubricating oils so chosen and compounded that a stable grease of good texture and firm consistency is obtained and is capable of being produced by rapid continuous or semi-continuous processes. -In the prior art, a number of successful aluminumfsoap-base greases have been prepared. Because of their smooth texture and other desirable properties, aluminum soap greases have come to be particularly favored for many uses, especially for the lubrication of chassis parts of automobiles, tractors, and the like. The prior art has recognized certain difiiculties, however, in the preparation of alminum soap greases, They pass through a peculiar transition stage in cooling from grease cooking temperature to normal tem-, perature anda hard, grainy and very unsatis factory structure is likely to result unless 1) the cooling is conducted very slowly with careful control, or -(2) certain specific crystallization modifiers are employed to prevent the development of grainlness, etc., during the transition from a rubbery structure to a smooth unctuous gel.

' In the older prior art it was considered essential to cool aluminum soap greases ver carefully, for example by running the molten grease into shallow pans where cooling was allowed to progr'es's very slowly. This was a very slow and tedious process. More recently, as disclosed, for example, inn-the patent to Sproule and Zimmer, No. 2,394,- 567, and in the patent to Beerbower (one of the present inventors) and Zimmer, No. 2,449,580,-it hasbeenfound that modern rapid production methods may be employed in making aluminum soap greases, provided crystallization modifiers such as alkylated mono-nuclear phenol or related materials such as resorcinol are used. Thus, in;

the Sproule and Zimmer patent, about 0.75% by weight of tertiary octyl phenol is added to an aluminum soap grease and such grease may then be prepared by mixing lubricating oil and aluminum soap at a temperature of about 280 to 300 F., and then running the. hot mixture through a rapid chiller, e. g., a continuous close-clearance water-cooled chiller of the thin layer or scraped wall typel Similarly, a grease-containing about 0.1 to 1% of resorcinol may be rapidly cooled as described in said Beerbower and Zimmer patent.

The patented processes and products just described are quite satisfactory, but the present in vention is based upon the discovery that it is readily possible, by a choice of the particular types of mineral lubricating oil employed, to make aluminum soap greases which can be rapidly chilled and which have excellent texture and and the product is found to be an excellent lubricating grease.

, Specifically, we have found that by the proper choiceand blending of appropriate types of mineral lubricating oil which are readily available, at least one of which contains as a natural ingredient a polar compound or group of compounds effective as suitable crystallization modifiers, a. good aluminum soap grease may be prepared. The efficient continuous rapid cooling process may be used with such materials. A lubricating oil distillate which, without finishing, contains active crystallization modifying material comprising alkylated phenols, phenolic derivatives, naphthenic acids, 'etc., is commonly obtained in the simple distillation of Venezuelan or Coastal type crude oils, The quantity of such modifiers is common- 1y of the order of 1 to 1.5% by weight, in the lubricating oil distillate. This is more than is desired and more than is needed to modify the soap crystallization in the rapid or close-clearance cooling process, and greases prepared solely with this oil have very poor structures. Hence, according to this invention, it is necessary to dilute the untreated distillate with a suflicient quantityof refined or neutral oil which has been treated (acid, clay, caustic. selective solvent, or the like) to reduce the free acid and phenolic content to very low values. The two oils are blended to obtain a stock having a modifier content which is about 0.1 to 1%, preferably 0.25 to 0.75% by Weight, based on the finished grease. The optimum amount varies, depending upon the rapidity of cooling and intensity of mechanical working. Byadjusting the proportions of unfinished distillate and neutral stock, the modifier content may be accurately controlled within any reasonable desired limits.

While the exact composition of the modifier which is naturally present-in crude naphthenic Venezuelan or Coastal oils is not fully known, it appears to be a mixture of polar compounds, phenols, organic acids, and acid-phenol substituted aromatics, all of which are soluble in potassium alcoholate or sodium hydroxide solution. These naturally occurring modifiers are effective to a very satisiactory degree for modifying the crystallization of aluminum soaps.

The extract from alkali treated oils may be used also by acidulating it. It contains modifiers of the same general type and may, under some circumstances, be an economical process.

In the drawing, there is shown a flow diagram to illustrate the simplicity and obvious advantages of the process more clearly. As shown therein, the Venezuelan or other naphthenic crude oil is subjected to ordinary vacuum distillation to separate the lighter fuel distillate and the heavier asphalt from the intermediate lubricating oil distillate, The lubricating oil distillate is then separated into two streams so that part of it goes to the grease cooking unit while another part. issubjected to normal finishing operations, If desired, lubricating oil distillate from other operationsmay be brought into the normal finish: ing stage for acid treatment, soda washing, redistillation over sodium hydroxide, and the like, as indicated above.

Ifhe finishedneutral stock is then taken to the cooker where it i blended, in suitable propore tions depending on the desired modifier content, with the unfinished distillate, and also. the aluminum stearate or other aluminum soap. Aluminum stearate is specifically preferred, but, other aluminum. soaps offatty acids of 12 to 22 carbon atoms such as hydrogenated fish oil acids, for example, may. be used. The saturated fatty acids oi this. range are preferred because of their superior. stability against oxidation. The propore tions oi finished and unfinished oils will usually be from about 1 to l parts by weight of finished or neutral stock combined with 10 to 2 parts by weightoi theraw or unfinished oil. Thealuminum soap. content, based on the weight of the finished fiease, is withinthe. limits of about 3% to 30 a range of 5 150.15% being generally preferred.

As the ingredients are mixed, they are heated toa temperature of at least 250 F. and may be heated as high as 350 F. The heating need-not be long continued. In the continuous process, for example, heating is only momentary, i. e., longenough for the ingredients to attain the temperature of 250 F. to 350 F., with complete solvation, and. the heated mixture is then passed in continuous how. to the rapid cooler.

The rapid cooler, which maybe. of the close clearance type, water jacketed, with or without scrapers-or a close fitting worm impeller, is arranged to bring the temperature downbelow the. normal transition temperature range of about 7,0? to 160 F'., for example to a temperature. of

between 7,0? and 100 F. From the cooler, the. product may be packaged directly inasmuch as the final setting up and crystallization of the soap: structure, which forms the body or framework'of the gel, takes place very satisfactorily in the. final package.

Although the flow plan just described suggests using oil whichlby-passes the finishing operation allies. wi h i hi h goes thr u he ish n operation, it will he self-evident that the finished stock may be any substantially neutral oil, derived from naphthenic or Coastal crude, or a Pennsylvania type oil. The latter, which is substantially neutral'when removed from the still, commonly will require no finishing treatment. The product of the invention thus may comprise various types of neutral or substantially neutral stock combined with the unfinished naphthenic oil.

Example As an example of the operation of this invention, the following may be cited: An unfinished Venezuelan distillate (from Lagunillas crude) and a finished Coastal distillate were selected as the two oil components. These oils had the following characteristics:

Untreated F 25 3:? fi flg Lubricating Viscosity at F. (SSU) 1214 916 Viscosity at 210 F. (SSU) 78. 4 70. 5 Gravity (A)? 18.2 23.1 Flash Point, F. (Open Cup)- 45 450 Pour Point. F. (ASTM), +5 0 Sapcnification No 1 2.1 0.14 Color'(Tag-Robinsom un Below 1 10% Cast (Color by reflected light) Blue-Green Blue These oils were then mixed with a commercial aluminum stearate in the following proportions:

Ingredient: Per cent by weight Aluminum stearate 6.00 Venezuelan distillate y, 62.30; Finished Coastal oil 31,70

Unwork-ed penetration (ASTM) 2,14 Worked penetration (ASTM) 326 1800 strokes worked penetration 3,2; ASTM penetration after passage through a h gh pressure grease un 340 ppearance. emi-transpar nt Oil separation (.6 months at 77 1?.) None.

The grease was subjected to all the conventional quality tests for pressure gun applicat'en, andwas found to be very satisfactory.

It isobvious that the proportions of the treated and untreated oils may be varied and the quanti ties and types of soaps, or the fatty materials:

from which they are formed may be selected as desired. The conventional modifiers such as antia.

oxidants, extreme pressure additives, tackiness.

, agents, corrosion inhibitors, etc., maybe employed if desired.

What is claimed is:

The process of preparing stable aluminum-base lubricating greases of smooth texture which com prises combining about 62 by weight of unfinished Venezuelan distillate mineral oil of lubricating oil viscosity and" containing about 1 to by weight of polar compounds including phenols, naphthenic acids, and acid-phenol substituted? aromatic compounds'with about32 of fin-ished:

Coastal oil as a diluent and about 6% of aluminum soap of substantially saturated fatty acid within the range of 12 to 22 carbon atoms as a thickener, heating the mixture to a temperature of above 300 F. and not higher than about 350 F., and thereafter rapidly cooling below about 100 F. in thin layers, accompanied by mechanical working.

AUSTIN E. CALKINS. RALPH DARLEY. ALAN BEERBOWER.

1 8 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,804,124 Southard May 5, 1931 1,902,635 Gebharclt Mar. 21, 1933 2,380,893 Zimmer et a1 July 31, 1945 10 2,431,453 Beerbower et a1. Nov. 25, 1947

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