US2115823A

US2115823A - Lubricating composition

Info

Publication number: US2115823A
Application number: US613132A
Authority: US
Inventors: Floyd L Miller; Winning Carl
Original assignee: Standard Oil Development Co
Current assignee: Standard Oil Development Co
Priority date: 1932-05-23
Filing date: 1932-05-23
Publication date: 1938-05-03
Anticipated expiration: 1955-05-03

Description

Patented May 3, 1938 UNITED STATES LUBRICATING COMPOSITION Floyd L. Miller and Carl Winning, Elizabeth, N. 1., assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application May. 23, 1932,

Serial No. 613.132

24 Claims.

The present invention relates to improved lubricating oils and more specifically tolubricating oils of low pour point and to methods for reducing cold test or pour point of such oils by the use of relatively small quantities of pour depressing agents. Our method will be fully understood from the following description.

Hydrocarbon oils used for lubricating purposes frequently contain waxy constituents which cause them to congeal at relatively elevated temperatures, say 30, 45, 60 or even at 75 F. or higher, depending on the amount of waxy constituents present. Butfor the high congeaiing point these oils would be good liquid lubricants at temperatures considerably therebelow and it is the practice in oil refining to remove wax, or a suflicient amount thereof, .for the purposein hand. We have discovered a class of substances, however, which may be added to oils in extremely small quantities and which in such quantities have the power of so modifying the crystal form or crystal growth that the oil remains liquid at temperatures far below their normal solidification or pour points. The materials which we contemplate in this connection are of the general class of solubilized polysaccharides, that is to say, the polysaccharides which have been rendered soluble in oily liquids and which comprise derivatives of cellulose, starch, sugar, dext'rin and the like. It is not necessary that these materials be greatly soluble but only to the extent of l or 2% and in some instances to even less. The solubilized products which we have particularly in mind are derivatives of the polysaccharides which contain hydrocarbon groups in' sutlicient quantity to bring about a solubility in oil to the degree indicated above. These hydrocarbon groups may be attached to the polysaccharide so as to form ethers or esters or similar compounds and are made by the meth- 40 ods now generally known in the art. The degree of solubility as indicated above depends to a great extent on the number and length of the hydro-v carbon chains and these are preferably straight chains, although branch chains and cycle groups are permissible. If chains of more than 8 or 10 carbon atoms, for example, preferably 10 to 22 carbon atoms, are attached to the cellulose molecule, for example, the material becomes relatively soluble and may be termed for our purposes freely soluble, which is to say that it becomes soluble to the extent of at least 2 or 3% and generally to even 10%. Where shorter chains are used the materials are progressively less soluble and may be so insoluble that they cannot be used at all for the purpose in hand. We prefer to use polysaccharide derivatives which are soluble to an extent of 2 to 10% or more, and as stated above, these derivatives may be esters, ethers or some similar derivatives. The hydrocarbon chains should contain at least 8 or 10, preferably 10 5 carbon atoms, and the number of chains should be such as to bring the total number ofcarbon atoms in the hydrocarbon radicals to 20 or more. The carbon atoms of the chain which are attached only to carbon or hydrogen may be termed the 10 carbon atoms of the hydrocarbon group.

For our purposes the esters have been indicated as suflicient and the cellulose or other esters of organic acids such as 'stearic 'acid, oleic acid, erucic or behenic and the like may be used. But 15 the lower acids such as lauric and the like are also entirely suitable though where two stearyl groups suffice, 3 lauric groups are desirable to give the desired solubility. synthetically produced acids,

for example produced by the oxidation of paraflin 20 wax or ceresin or, of hydrocarbon oils with air or other oxidizing agents such as nitric acid or similar substances may be used. Mixtures of these synthetic acids may serve our purpose and these acids may be used in connection with the natural acids as indicated above. 01 the ester derivatives the mono-, di-, or tri-acid esters are all suitable, although it is preferable to use a tri-ester in order to obtain greater solubility. Of the ethers' it is preferable to use those which are 30 soluble to the same extent as theacids used above and the ethers of decyl alcohol, or tetradecyl, cetyl and the like may be used although these are given merely as examples. The ethers, in fact, may be made from any of the higher halides, for 35 example containing more than 8 or 10 carbon atoms, and as i diated in connection with the acid radicals hy rocarbon derivatives should contain enough groups to provide at least 20 and preferably more carbon atoms in the hydrocarbon to groups. 1 f

The amount of these solubilized polysaccharides to be used for our purpose is, of course, of considerable importance and generally theamount will be less than 2% by weight. It is preferred to 45 use in the neighborhood of /g to 1% and we have observed that there is a fairly well defined optimum quantity for pour inhibition. If large amounts be used the oil is considerably thickened and the pour ,point'is not so low as might be 50 obtained with the optimum quantity. We prefer to use the agents in such small amounts that the thickening caused by solution of these materials is slight but in some instances the thickening will be appreciable. In general we prefer to'use the 55 that is to say, in proportions suitable for pour inhibiting without causing substantial thickening.

V *The agents which we prefer among the polyiii) saccharide derivatives are those of cellulose because they are cheaper and more effective than the other substances, but sugar, starch, dextrin and the like are suitable and give substantially similar effects. There may be some difllculty in dissolving these substances even through they may have been termed freely soluble, but generally heating to 300 or 350 in presence of the oil is sufficient to cause the material to go into solution. The entire quantity of the agent should be dissolved and the oil should be both clear and brightso that the appearance gives no indication of any addition agent whatever. A slight turbidity may not .be objectionable but we prefer to produce-perfectly clear oils and the slight excess over what is clearly soluble should be removed. These agents do not in any way decrease the value of the oils as lubricants or change the properties such as flash, color, carbon content'and the like to any substantial extent.

As an example of the effect of such substances the following may betaken as illustrative:

An oil known as Manchester Spindle is selected with the following specification, but unblended:

Gravity 30. 5 Viscosity at 100 F. 148. 6 seconds Saybolt Viscosity at 210 F..'. 42. 6 seconds Saybolt Flash 390 Color 11.0

Carbon 014% Pour point 30 F.

To such an oil cellulose trilaurate is added in small amounts from 0.1 to 2% by weight and the properties of the 'oil are shown in the following table:

Gravity an 30.5 30.5 30.5 30.5 va. 1oor 165 110 200 302 Vis.@2i0 F. 4 43.1 44.0 41.0 52.6 Pour point 5 -5 0 to- F. The other properties of the oil are substantially unchanged. These oils are .found to be perfectly stable and wholly satisfactory for the operations to which mineral lubricating oils are ordinarily devoted.

Cellulose stearate or oleate or the naphthenate formed from naphthenic acids to be found naturally occurring in petroleum of the type obtained in the Texas fields and also in the Russian or Rumanian fields are suitable for our purposes, and the cellulose esters of acids obtained by the oxidation of paraflin wax with air at temperatures from 100 to 160 C. in the presence oi catalysts of the type of previously oxidized paraffln, manganese, cobalt salts, organic acids, barium cinnamate and the like may be used. The ethers of cellulose are also perfectly satisfactory such as decyl cellulose, etc.

Our invention is not to be limited to any particular solubilized polysaccharides or to any method of making such substances, nor to any theory or explanation of their eifect on waxcontaining oils, but only to the claims in which we wish to claim all novelty inherent in the invention.

We claim:

1. A composition of matter comprising a viscous waxy mineral oil containing an ether of cellulose soluble therein and in pour depressing proportions less than 2% by weight.

2. A composition according to claim 1 in which the hydrocarbon group of the cellulose ether is straight chained and contains at least 20 carbon atoms.

3. A composition according to claim 1 in which the hydrocarbon group of the cellulose ether contains a plurality of hydrocarbon radicals containing a total of at least 20 carbon atoms in the hydrocarbon groups.

4. A composition according to claim 1 in which an alkylated cellulose is permanently soluble and present to the extent of .1 to 1%. 4

5. A composition of matter comprising a viscous mineral oil containing wax and a cellulose ester of stearic acid in pour depressing proportions less than 2%- by weight.

6. A composition ofmatter comprising a viscous mineral oil containing wax and a soluble cellulose ester of an acid containing from 10 to 22 carbon atoms and in pour inhibiting proportions less than 2% by weight.

'7. A composition of-matter according to claim 6 in which the acids are of the type produced by the low temperature oxidation of paraiiin wax.

8. A composition of matter according to claim 6 in which cellulose trilaurate is used.

9. A composition of matter according to claim 6 in which the ester is present in proportion from 10. A composition of matter comprising a viscous waxy lubricating oil containing ,6 to 2% of an oil soluble cellulose derivative selected from the class of ethers and esters.

11. A mineral oil composition containing wax in amount suflicient to cause the oil to have an undesirably high pour point, and a mineral oil soluble poly-saccharide in amount less than 2% by weight of the composition and adapted to depress the pour point of the oil.

12. A mineral oil composition containing wax in amount suflicient to cause the oil to have an undesirably high pour point, and a mineral oil soluble poly-saccharide derivative made .freely soluble in the oil by the addition to the poly-saccharideof a hydrocarbon radicalto form a compound of the class of esters and ethers, said de-' rivative being added to the oll in pour depressing proportions less than 2% by weight of the composition.-

13. A mineral oil containing wax in amount sufficient to cause the oil to have an undesirably high pour point, and a' cellulose derivative containing a hydrocarbon radical added to the cellulose, such derivative being'freely soluble in the oil and present in proportions less than 2% by weight but suflicient to materially reduce the pour point.

14. A composition of matter comprising a-waxy cellulose derivative with a plurality of hvdrocarbon radicals containing a total of atleast 20 carbon atoms in the hydrocarbon groups.

15. A composition of matter according to claim 13 comprising a viscous mineral oil containing wax and a cellulose ester soluble therein.

16. A composition of matter according to claim 13 comprising a viscous mineral oil containing wax and a cellulose ester soluble therein, such ester being derived from an organic acid containing at least 20 carbon atoms.

17. A composition of matter according to claim 13 comprisng a viscous mineral oil containing wax and a cellulose ester soluble therein, such ester produced by combination of a plurality of acidic groups with the cellulose and providing a total of at least 20 carbon atoms in such acidic groups.

18. A lubricating oil containing wax in amount suiflcient to causethe oil to have an undesirably high pour point, and a small amount of a sub.- stance selected from the class consisting of mineral oil soluble poly-saccharides and their derivatives, such amount being suificient to mate-.- rially reduce the pour point of the oil but insufflcient to increase the Saybolt viscosity measured at 210 F. by more than 10 seconds.

3 19. Composition according to claim 18 in which the poly-saccharide derivative is a soluble cellulose ester of an acid containing from 10-22 carbon atoms.

20. Composition according to claim 18 in which the poly-saccharide derivative is a soluble cellulose ester of an acid produced by the low temperature oxidation of paramnwax.

21. A low pour point mineral oil composition comprising a wax containing mineral oil and a condensation product of sucrose and an aliphatic acid the condensation product being present in relatively small amounts suflicient to cause a lowering of the pour point of the mineral oil.

22. The composition of claim 21, wherein the acid used is a fatty acid.

23. The composition of claim 21, wherein the acid used is stearic acid.

24. A low pour point mineral oil composition comprising a mineral oil and a condensation product of sucrose and an aliphatic acid the condensation product being present in' relatively small amounts sufiicient to cause a lowering of the pour point of the mineral oil.

FLOYD L. MILLER. CARL WINNING.