US2074039A - Nonleaking lubricant - Google Patents

Description

Patented Mar. 1s, 1937 UNITED 'STATES PATENT ol-Flci-z Roselle Park,

ware

N. J., assi Development Company,

gnors to Standard Oil a corporation of Dela- Application March 29, 1935, Serial N0. 13,616

8 Claims.

The present invention relates to a method for improving lubricating oils for industrial uses, and more speciflcally'fory use in small machinery, textile mills and the like. The invention will be 5 understood from the following description.

In the drawing, Figure 1 shows a graphical representation of the relation between oil consumption and power consumption in a journal bearing when used in connection with normal 10 hydrocarbon lubricating oils and ordinary blended oils; and Figure 2 shows asimilar representation of the comparison of oil consumption and power consumption ofthe oils now in use and of the present improved lubricants. 15 In the lubrication of large machinery such as turbines and similar equipment. it is economical vto provide methods and devices for recovering oil. These generally consist of an oil storage, feed and return pipes, and for this reason the o loss of oil is so small as to be negligible. All of the oil is used and its full value is thus realized. In small machines, however, it is rare that such systems are economical, and in textile mills, for example, where there area large number of small 5 independent'bearings to be lubricated, the loss of oil due to leakage is very large, but itis still usually uneconomical to employ recovery methods and apparatus therefor but the loss is objectionable nevertheless. For this reason, it is very desirable, if possible, to prepare oils which will have the least possible leakage tendency.

It is equally important in lubricating oils to employ a suiflciently low viscosity oil so as to keep the power consumption as low as possible com- 5 patible with good lubrication. It is thus found with ordinary straight mineral oil, oils including oils blended with fatty compounds, soap, aluminum stearate andthe like that increasing viscosities are desirable .in respect to the oil o consumption, but undesirable in respect to power consumption. Therefore, in each instance it is a matter of great importance to choose an oil of such viscosity as to give the best return in respect to both power consumption and oil loss.

i In the present invention it has been found that certain oil compositions are much morefavorable in respect to oil consumption and power consumption than the straight mineral or blended oils heretofore used. This is of especial l importance for textile mills where a large number of small machines, looms, for example, are operated with journal bearings and without any device for recovering the oil. the present compositions, while adequate for carrying the load, s how greatly reduced leakage It is found thatwith little or no increase in power consumption. Indeed, it is frequently the case that the power consumed is even less than with the normal oil of substantially the same viscosity.

The type and quality of the base oils may be varied to suit the particular mill requirements and is, oi course, a mineral lubricating oil which may be derived from any particular source; for example, from paraffine or naphthene crudes. 'I'he viscosity may vary throughout the range of the ordinary lubricating oils, say from about 75 seconds to approximately 2,000 seconds Saybolt at 100 F., depending on the load requirements for the particular bearings and other factors.

To the base oil is added a very small quantity, say less than .5% of a linear hydrocarbon poly- -mer of isobutylene which is soluble in the oil and which is characterized by a molecular weight in excess of 30,000, this Weight being determined by the Staudinger method, Die Hochmolekularen organischen Verbindungen, H. Staudinger, 1932, Berlin. The actual amount of the polymer used in any particular depends to some extent on the particular circumstances, but quantities as low as .001% may be satisfactory, especially where the molecular weight of the polymer is very high, say above 100,000 and it is rare that more than .5% is ever used. For ordinary uses .1% is satisfactory.

The preferred polymer is produced from isobutylene which has been carefully purified and polymerized at a temperature below 50 C. and preferably at temperatures from -80 to -1l0 C. in the presence of active metal halide catalyst such as boron fluoride, although other catalysts may be employed. VThe low temperatures may be readily attained by carrying out the reaction in the presence of liqueed ethylene and allowing the same to evaporate at atmospheric pressure fory example. It should be understood that there is an entire series of linear isobutylene polymers ranging in molecular weight from below 1,000 and up through the range indicated above. but there is a critical molecular weight which marks off the polymer satisfactory for the present purposes. Polymers having molecular weights below about 30,000 when added to the oil merely increase viscosity and the blends showan yoil leakage-power consumption relation comparable to that displayed by a when polymers above 30,000 are used, a totally different effect is noted and the oil consumptionpower consumption relation is vastly Vdifferent from that shown by normal cils of the normal unblended hydro-- carbon oil of the same viscosity yrange. However, t

same viscosity. The polymers which are used, as stated before, have molecular weights above 30,000 and they may be as high as 100,000, 200,000 or even more.

A second ingredient of the oil is a soap. For this purpose the soda soaps are preferable. not only because ot their cheapness but also because of their superior effects in the oil. Sodium oleate may be usedor similar salts of other fat acids such as stearic or palmitic, or mixtures of the same. Similarly, the alkali metal salts of synthetic acids may be used, particularly those prepared by the low temperature oxidation of oils and waxes. The amount of the soap is quite small and is ordinarily less than 1% or 2%. As little as .1% shows a substantial effect, but .5% is usually employed.

While the soap is not an absolutely essential ingredient of the present compounds, the latter are greatly improved by their addition. For example, in many cases the addition of the polymer to the oil will bring about a substantial decrease in oil consumption, but in many cases it brings about also a slight increase in power consumption. However, on the addition of the soap. it is usually found that both the oil and the power consumption are considerably reduced. These eiects, while noticeable in oils of all the viscosity ranges, are most noticeable in the range from say 200 to 900 seconds Saybolt. Blends of oil and soap, which do not contain the polymer do not show the reduction of leakage.

The above substances are the principal ingredients of the present compounds although it will be understood that other agents may be added, for example, higher alcohols, glycerine or glycol, fatty acids or esters. or other polar compounds which have the property of reducing frictional losses. Resins vmay also be added for certain purposes, as well as aluminum soaps such as naphthenate, oleate or stearate or dyes, oxidation or pour point inhibitors none of appear to interfere with the eiIect of the primary ingredients.

To illustrate the operation of the improved oils and'the advantages of these compositions, the following examples may be considered.

Example 1 A large number oi' tests on straight minerals and mineral oils blended with soaps, fatty substances and the like were run on a bearing which consisted of a one-inch diameter steel shaft in a bronze sleeve of four-inch length. The oil was fed at the center of the sleeve and then allowed to leak at the ends. This'oil that leaked out was collected and leakage thus determined in cubic centimeters per minute. The runs were conducted at a speed of 1,200 R. P. M. obtained by means of `a D. C. motor, and power consumption was measured by the difference in wattage consumed by the motor and the bearing, and by the motor alone. y

It was found in general that power consumption increased with viscosity and oil consumption decreased therewith. The entire eifect appears to be a viscosity phenomenon. The power consumption when plotted against leakage made a fairly smooth curve which is represented in Figure 1 of the drawing. Since there was no attempt to control all of the variables, such as temperature and the like, the curve is shown but the deviation from the mean was not great which drawing and was undoubtedly within the experimental error at all times. Care was taken to insure that the bearing and motor were in substantially the same condition during all of these comparable tests.

In the above tests. the oil and oil blends represented on the curve varied in viscosity from to 1,200 seconds Saybolt at 100 F. and samples included straight mineral oils of that viscosity range, mineral oils, oils containing lard oil, sodium and potassium oleates or other soaps, aluminum stearate, sodium or calcium sulfonates, rosln and the like. It will be seen that the particular composition of the oil did not have any substantial effect on the relation between oil consumption and power consumption.

Example 2 having viscosities of about 200, 500, and 900 sec-v onds Saybolt at 100 F. respectively, and similar oils containing .1% of an isobutylene polymer, having a molecular weight of 60,000 to 100,000 together with .2% of sodium oleate.

The oil leakage and power consumption tests were carried out according to the same procedure used in Example 1 and the data are plotted in Figure 2 of the drawing, curve A representing the straight mineral oils, while curve B represents the oils containing polymer and soap. The wide dillerence between the leakage and power consumption in the present compositions and the straight mineral oils can be readily seen from the Example 3 Data. some of it included in Example 2, on oils, unblended oil and oil blended with the soap alone or with the polymer alone and with the combinatiglns of soap and polymer are shown in the table The present compositions do not show any undesirable eilects which would in any way hinder their employment for the most exacting uses. For example, it is found that the present oils can be scoured from clothes which they have stained without the slightest dimculty. In practical tests it is-found that over 99% could be removed without difilculty and that they are equal to ordinary mineral oils in this respect. The oils have excellent lubricating properties suicient to carry such loads as will be normally applied to them in textile mills. They are also quite stable toward heat and the eiects of air.

These oils may also be used in conjunction with emulsiers, colloidal materials such as graphite, clay, zinc oxide, etc., sludge dispersers. low molecular weight oil thickeners, volitalized oils, waxes, extreme pressure agents, organometallic compounds, and the lik 'I'he oils prepared according to may in many cases be employed this invention in soluble oil compositions for oiling textile fiber cordage,

leather and similar materials.

The present invention is not to be limited by any theories of the advantages of the present oils nor to any specific composition, rmolecular weight of polymer, or speciilc soap or combination of ingredients, but only to the claims in which inherent in the We claim:

1. A lubricating oil adapted for low power consumption and leakage, comprising a mineral oil lubricating oil and a small quantity, less than .5% of an oil soluble linear polymer of isobutylene lubricating oil having a viscosity'in the ran e of about to 2,000 seconds Saybolt at 100 F., and less than .5% of an oil soluble linear polymer of viscosity from about 200 at 100 F., less than .5%

isobutylene having a molecular weight in excess -ot 30,000.

3. A lubricating oil according to claim 2 in which the polymer has a molecular weight within the range from 30,000 to 300,000 and is present,

in proportion within the limits of .001 to .5%.

4. A lubricating oil according to claim 2 in which the polymer has a molecular weight within the range from 30.000 to 300,000 and is .present in an amount from .001 to .1%.

5. An improved consumption and leakage comprising a mineral lubricating oil having a viscosity in the range of 75 to 2,000 seconds Saybon at 1oo F., a, small quantity, less than .5% of an oil soluble linear polymer of isobutylene having a molecular weight in excess of 30,000 and a small quantity of an alkali metal soap.

6. A composition according to claim 5 in which a sodium soap is used.

7. A lubricating oil for low power consumption and leakage comprising a mineral oil having a to 900 seconds Saybolt of a polymer of isobutylene having a molecular weight in excess of 30,- 000 and less than .1% of a sodium soap.

8. A composition according to claim 7 in which the amount of polymer is between .001 and .1%

`and the amount of soap is between .1 and 1%.

JOHN c. z i. EJNAR, W. cARLsoN.

lubricating oil of low power`

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