US2376306A - Mineral oil composition - Google Patents

Description

' Patented May 15, 1945 p John H. Bishop, Wenonah, N. J., assignor to Socony-Vacuum Oil Company, Incorporated, New York, N. Y., a corporation of New York No Drawing. Application March 17,1942,

' Serial No. 435,077

6 Claims. (crass-41) This invention has to do with lubricants; and

is more particularly concerned with lubricants for ferrous metal surfaces in anenvironment where such surfaces are also subject to contact with water and in consequence are likely to rust.

As is well known to those familiar with the art. difficulties have been experienced during I118 operation of steam turbines, and particularly'during the initial operation or new steam turbines, because of therusting of ferrous metal: 10

parts. The combination offresh (not previously .used) oil; clean, new metal surfaces; and moist conditions of'operation of new steam turbines appears particularly conducive to rusting dimeulties. Particles of rust formed on or carried to tne bearing -,surfaces of small clearance, such as the governor, for example, tend to: cause sticking, which renders them inoperative. In

cases of severe rusting, bearings may be injured.

This rusting phenomenon under conditions or 6 the type outlined above is evidently theresult of improper or inadequate "wetting" of the metal surfaces with oil, thus permitting a preferential contact of the surfaces with the water which is present. One expedient used in the past to prevent rusting. under these conditions has been to mix with the new oil several per cent of an oil which has been previously used in turbine operation for a considerable period of cause the oil to -wet". more adequately and better adhere to the metal surfaces. Such an expedient, however, not only introduces those.ox.-

ldation products'which protectagainst rusting The oxidation products in the used oil 0.05% to'about 0.2% or in aniline dissulpnide. and from about 0.01% to about 0.1% ofdegras fatty acids, in a turbine oil will notonly. prevent undue rusting of themetal parts of a new turbine, especiallynuring the break-in period, of a newturbine, when such problem. is most acute, out will, in, addition, increase the effective life .01 the oil composition. V

I am aware of the fact that it has been proposed, in U. S. Patent No. 2,151,353, to use degras fatty acids in relatively large proportions of. from 5% to 20 %'in coating and drawing compositions.

The present invention distinguishes over the aforesaid disclosure in the discovery that with the combination contemplated herein, a' jvery I small quantity-of the order of 0.10% or less of degras fatty acids may be used to improve 4 t'urbineoils. I

.when'large quantities, such as'5% to 20%. (as

disclosed .in' the aforesaid patent), of degras fatty acids are used in turbine oils substantial combination with a minor proportion of an aniline disulphide in turbine oils, the emulsification tendencies, of the oil composition are substantially. reduced, so much so, in fact, that tne compositions contemplated herein are extremely efrectiv'e and desirable for use in turbines. As small a quantity as 0.01% ofthe liegras fatty acids may be used in the turbine oil compositions 1 contemplated herein to obtain improvementin rust prevention and effective life of the oils Thus.

and undesirable emulsif cation of the 'oil is caused. I have found, however, t at when not more than 0.10% of degras fatty acids is used in f i but iiftroducas as-well other oxidation products, 535 i bs t the u ti y o germs fatty which promote the formation of sludge and acidf. V a h W be used In t in 11 c m vent rusting-have tlie undesirable property of .40 an upper. limit the neishbbrliwd Ora-19% positions contemplated determined by a lowejr'limit of about-0.01% below which effec v tive anti-rustinz'properties are not obtained, and

ity and.increase emulsifying tendencies. other} materials such as stearic acid-have been pro- .posed; but such additives, although they do preminor proportions of both an aniline disulphide I will prevent undue rusting of the metal parts.

" unduly raisin: theacidity (neutralizationnum ber, or N. N.) of the oil and of accelerating the development of acidity in use.

r The present invention is predicated ,upon the eral oil, 'such *as a turbine oil or the like, of

and dexras' fwool grease). fatty acids provides wetting of the metal surfaces with the oil and This. new and'novel -combination of improving agents in a turbine oil functions in several ways in that'it adequately "we the metal surfaces and inhibits the deleterious effects of'oxidation I upon the oil. The incorporation of from about 60 I above which the emulsion problem becomes too The'presevere for commercial practicability. ferrewquantity of the desras fatty acids for the w purpose of this invention is of the order ,of 0.93%. Y discovery that the admixture with'a viscous min- Broadly,-.this invention contemplates the incorporation, in the aforesaid turbine oil, ofdegr'as fattyacids 'whichare obtained from. degra's,

a mixture of fatty acids,'fatty alcohols and fatty esters. Degras fatty acids may be prepared from degras by various means, and may be purchased on the market. The fatty acids vary inneutral' ization .nuinberand it is believed that such vari-' ation is associated with the method of preparation andmay or may not be associated with differences in degras itself. For example, typical degras fatty acids were prepared i the following ways.

A specimen of wool grease was saponifled under pressure with alcoholic potassium hydroxide.

The unsaponifiable material (fatty alcohols and. fattyesters) was-removed from the-soap mixture formed in the saponification step, with solvent. The fatty acids were recovered by acidifying the soap solutionwith mineral acid and extracting with solvent. The fatty acids thus ob- 0.03% of the fattyacids having an N. N. of from i tained'were free of mineral acids and solvent,

and had a neutralization number (N. N.) of 163.

' A specimen of wool grease was saponifled under pressure with alcoholic potassium hydroxide and with methyl ethyl ketone as a solvent. The unsaponiilable material was removed with solvents, the fatty acids were recovered from the soap soof aniline disulphide and representative degras time. In some instances. as will appear from the 7 table below, the temperature was 140? F. .and in others it was 167 F. also, as will appear from the,

table, the time intervalwas 24 hours in some of the tests and in others it was 48 hours. The mixture was agitated constantly by a motor driven stirrer. The improving agents used inthe oil I samples tested are indicated by the abbreviations lution with a solvent after acidification, and the I solvent was subsequently removed from the fatty acids. The fatty'acids. so obtained were free of mineral acid and solvent, and had a neutralization number ranging from 86 to 147. The fatty acids of lower N. N., from 86 to 110,. were less eflective in turbine oils than were those of higher N. N., from 110 ton-i7. 'For example; 0.02% to 110 to 147 gave perfect rust tests (des unease:

low); whereas tho'se fatty acids havin an N. N. of from 86' to 110, while effective anti-rustingagents,- were requiredin larger amountsto 'pro- -duce' good results.

All degras fatty acids are effective for the pur poses of this invention, and particularly eifec-' tive-and preferred-are those fatty acids obtained from. degraswhich have a neutralization number of from about 110 to about 170. e In combination withthe degras fatty acids inthe aforesaid turbine oils is an aniline disulphide,-

- that'is aniline'disulphide itself or an alkyl-sub stituted aniline disulphide, which functions as an.

antioxidant.

The, aniline disulphides conteinplated hereinmay be represented by the general A. D. S. (aniline' disulphide) and D. F. A. (degras fatty acids). The neutralization number (N. N.) of the degras, fatty acid used is also indicated.

Table-II 20 r I P Per ondition Oil mpmvmg. cent oisteel agent I cent water l hrs. Spqqimens N'0ne 1.0 140 24 Rust. 11.1). 0.1 "1.0 140 24 Do; A.D. 0.13 1.0 140 24 Norust.

' D. F.A ...t 0:1

iN.l\.=l63) I r A .D.S 0.l 1.0 140 24 Do. D; F. 0,02 1 N. N.=l63) 1 L A -1118 0.1 10.0 107 48 Do. s llfilfimifi) 0.02 A 3 a v 11..-... D.S 0:1 10.0 167 (24) D'o. 0.01 y 48) .130.

s 10.0 107 48 Bust.

10. 0 167 48 Do. 10.0 167 48 No rust.

' disulphide and degras fatty acids to inhibit the wherein, R and R" are selected from the group consisting" of hydrogen and aliQl radicals.

The oil used in the composition hereinb'efore r describbd maybe of the type normally used for the lubrication of turbines. In general,

the oil may be defined as a viscous mineral oil 1 iron 100 to. 600 seconds at 100 Fi- Typical tut- .bine oils with which a hnixture of an aniline di- I To the efl icacy of the combination 'e disulphide and degras fatty acids in turbine oils-typical turbine oil compositions .fractionhaving'a Sgybolt'Universal viscosity of deleterious effects of oxidation upon turbine oils is shown by the results-of the following Brown- 'Boveri. oxidation teststabulatedbelow in Table 3 III. A typical turbine 0Q coinpiosition, as contemplated by the present "invention, comprising oil A, 0.1% ofaniline disulphide and 0.02% of degras fatty acids (N. N. =l63), was compared with an oil composition-comprising oil A and-0. 1%, of aniline disulphide. That the oxidation characteristics of the oil were only slightly changed by the addition of degras fattyacids is evident from the results given in Table 1 Tabieru on f gg g a. eent l m N.N. Sludge A A.D.S. 0.1 15 0.03 3

A.D.S.- 0.1 24- .0.05 .1 3- D. F, A 0.02

From the foregoin'git will be seen that minor .moportionsof an aniline disulphide and degras;

fatty acids in turbine oils will provide lubricants which may be used =efl'ectively in the presence of moisture to prevent rusting of ferrous metalparts L followingspeciflcations; e I

- eu urn. Q -28.4 22a .ate. 1 5 g 9 385 420 g'iflgsgr i 1 1% its-15s 001 t. moi. "84.5 250.5 43 01 -.2

oil. A and B and very small: amounts by the moisturev present, and to prevent changes in the oxidation characteristics ofsuch oils in such an environment. It is to beunderstood that although we have herein descrilkd and illustrated the invention with certain preferred mineral oil.- blends, the invention is not restricted to the specific examples given but includes within its scope whatever changes fairly come withmthe spirit oftheappendedclaims.

consisting aniline disulphide m; alkyl-substl- Iclaiin:

1. An-oil composition adapted for the lubrication of ferrous metal surfaces in an environment containing water, comprising aviscous mineral oil having in admixture therewith a minor proportion, from about 0.01% to about 0.1%, of degras fatty acids and a minor. proportion, from about 0.05% to about 0.2%, of a compound "selectedfrom the group, consisting oi aniline disulphide and alkyl-substituted aniline disulphides.

2. An oil composition adapted for the lubrication of ferrous metal surfaces in an environment containing water, comprising a viscous mineral 'oilhaving in admixture therewith a minor proportion; about 0.03%, of degrasjatty acids and a minor proportion, from about 0.05% to about 0.2%, of a compound selected from the group consisting of aniline disulphide and alkyl-substi-" tuted aniline disulphides. r

3. An oil composition adapted for the lubrication of ferrous metal surfaces in an environment containing water, comprising a viscous --mineral oil having in admixture therewith a minor proportion, from about 0.01% to about 0.1%, of .degras-fatty acids having a neutralization number of from about 110 to 170, an'd a.

minor proportion, from about 0.05% to about 0.2%, of a compound selected :Irom the grouptuted aniline disulphides.

4. An oil composition adapted for the lubrication of ferrous metal surfaces in an environment containing'water, comprising a viscous mineral oil having in admixture therewith a minor pro- -porti0n,'. from about 0.01% to about 0.1%,of

degras fatty acids having a neutralization-number of from about 110 to about 170, and a minor proportion, from about 0.05% to about 0.2%, of

aniline disulphide.

5. A turbine oilcomposition comprising a mineral oil fraction having a Saybolt Universal viscosity of from 100 seconds to 600 seconds at 100 .-tion of ferrous metal surfaces in an environmentcontaining water, comprising a viscous mineral oil having in admixture'therewith about 0.03%v 'of degras fatty acidsfand about 0.1% of aniline.

F. and having in admixture therewith a minor proportion, from about 0.01% to about 0.1%,. of degras fatty acids and a minor proportion, from about 0.05% to about 0.2%, of a compound selected from the group consisting of aniline disul-.

'phide and alkyl-substituted aniline disulphides.

*6. An oil compositiomadapted for the lubricadisulfide.

JOHN H. BISHOP.