US2828263A - Water-resistant sodium greases containing amides - Google Patents

Description

-Ed States Patefif WATER-RESISTANT SODIUM GREASES CONTAINING AMIDES No Drawing. Application January 28, 1957 7 Serial No. 636,464

10 Claims. (Cl. 252-421) This invention relates to sodium base lubricating greases having improved water resistance. It relates also to amethod of producing such water-resistant sodium base greases. I

Althoughgreases thickened with sodium soaps are of great value for certain lubrication, utilizations because of their high melting point, they are notably lacking in-water resistance and therefore cannot be used where water may get into the bearings where the grease is employed. It has been found, however, that the usual sodium soap greases can be modified by the addition of an N-alkyl substituted amide of a higher molecular weight hydroxy or keto fatty acid or an amide product as defined hereinbelow, to the sodium base grease either du r. ing or following its preparation imparts the property of.

water resistance to a great extent.

It is an object -of this invention, therefore, to prepare a water-resistant sodium base grease.

It is a further object of this invention to providea method of preparing a water-resistant sodium base grease.

It is another object of this invention to provide a water-resistant sodium base grease by incorporating in the grease an amide product which has the properties of imparting water resistance to the grease.

According to this invention, a sodium base grease is prepared following the usual procedure for preparing such greases and at some point in the preparation of the grease or following the normal procedure, between.

about 0.5% and by weight of the total grease of an amide or amide product is added and dispersed-in the grease. Upon completion of the preparation of, the grease or completion of the dispersion of amide follow 5 to '10 or 15% by weight, based on the soap stock,

of a mineral lubricating oil. This mixture is stirred and heated to approximately 160, 'F. and sufficient sodium hydroxide, as a, 5.0%.solution of NaOH in water, is added to' completelylneutralize thefats and/or fatty acids employed? The mixture is then vheated to. fcomplete' the" saponifica'tion, the temperature reaching 260-270 F. at this time. To the soap mixture present in the kettle, mineral lubricating oilis added slowly with mixing until approximately one-third to one-half of the total amount requiredfor the batch has been added. At this point,

the free alkalinity is adjusted sothat there will be present approximately 0.1% of free alkalanity calculated as sodium hydroxide. The amide oriamide product is added,

and the mixture heated to 310 320 F. with agitation to complete dehydration, and the remainder of the oil is then added. During the addition of the oil oxidation inhibitors such as those normally added to greases may be incorporated. During the addition of the final amounts of oil, the batch is permitted to cool. Substan tially the same results are obtained if the grease is completed without the addition of amide and following this, the grease. then reheated to a point sufficient to melt the amide, the amide then added and dispersed by mixing and the product cooled.

'As a modification of the above methodof preparation, the sodium grease may be made following the above procedure with the change that the final heating to complete dehydration is effected by heating the mass to 400-420 F. to produce a melt and following completion of the addition of lubricating oil at about this tempera- 15-20 to 100 or over. treated paraflinic' mineral oils of lubricating viscosity are used. Particularly satisfactory oils are the dewaxed and solvent-treated Western mineral lubricating oils having viscosity indices between about 80 and 90 and viscosities between about 30 and about 100 SSU at.21.0 F.

' '1 a The amides or amide products which are useful in preability to resist the washing effects or emulsifying effects paring water-resistant sodium base greases are preferably those prepared by reacting a diamine, such as ethylene diamine, with a hydroxy or keto fatty acid, as for example 12-hydroxy stearic acid or 12-keto stearic acid,

fatty acids which may be employed to produce useful additives for the purpose described will contain from 12 to 22 carbon atoms and preferably one hydroxy or keto group, although dihydroxy or diketo substituted acid may be employed. 2

Another class of amides which may be employed ar the simple N-alkyl substituted'hydroxy or keto fatty acid amides produced by reacting alkyl monoamines with hydroxy or keto fatty acids of the class described hereabove. The alkyl group of the alkyl monoamines will contain from l-lO carbon atoms. This latter class of amides, which will be referred to herein as monoamides,

.are' not the full equivalent of the diamides described above, however, they do impart a certain degree of water resistance and therefore are to encompassed by this invention. I H W Methods of preparing the monoand diamides of this invention are well know A typical method of preparing these compounds is as follows. l i

A chemical equivalent mixture of a diaminesuch. as ethylene diamine and'a hydroxy or keto fatty acidsuch;

as 12-hydroxy stearic acid is converted into the corresponding, diamide by heating this mixture of reactants in the presence of a solvent such as hexane or petroleunr naphtha under reflux using a water trapin the reflux line. Heating continued until the productionof water ceases. ,Following this, treatment the solvent may be removed by distillation. By this or other means of Patented Mar. 25,

These include naphthenic and 'paraffinic type oils ranging in V. I. from Preferably dewaxed and solvent Similar products equally, useful are pre-v be considered as being ainidation there is produced a compound having the following formula:

' o H H II I I II RCNR C-R v where-R is a hydroxyor keto' fatty acid radical-bf 12 to 2 2 carbon atoms, preferably; 16 to 20 carbon atoms; and R is the bivalent hydrocarbon portion of the diamine of 2 to 8 carbon atoms and prefe'rablyQ to'"4 carbon atoms.

The simple amides are prepared by substantially the sameprocess, using, however, a mono-amine such 'as propylamine in place of the'diamine. Thus'when an alkylamine is reacted with a hydroxy-or 'keto' fatty acid under dehydrating conditions, the lresulting iproducfwill be a compound of the formula R C-N-R" t t/Here n: is-the hydroxy or keto fatty acid-radicalhavirig l'2'to 22 carbon atoms and preferably l6 -to 20-carbon atfdfiis and R" is a saturated alkyl radical of 1 to afhonatonis and preferably -2 to 6-carbon atoms.

Itispo's's'ilfle, and in fact particularly with th'e'-higher diamines it is -known that side-reaction products are forif'r'ied during the amidation reactiqn. The reaction? mixontaining' any such side reactionproductsmay be us'ed 'and-will impart substantially the same degr'eeof water i'es'istancetothe sodiumgreases as the'pure amides and Gian-tides :For this reason the terms amide and dianiide will'he used herein to cover the-pure materials a's'wve'll as th'e amidation products 'whichmay or may notei l 1,.

"Inf'rdef to dtermine the water resistance oft'greases described 'a has'been employed which will -be"'r"eferi' :0 ef ein asi the hearing test; In this test: a ball he tig'as'sernbly isp acked with -grease and operated at 'speed of 600 R. P. M. while directing a streamof- Wa'tef'againstthe Hearing for a period of one hour. The

diat'e of the water stream is constant throughout the testing of all samples. In some tests the water' is maintained at IO O F. and in others'the temperature is' maintained at 1801F. The bearing is weighed before' thfetest'andfollowing'thetest the bearing is dried and Weighed again to determine the loss of grease.

' 'Ihismethod of determining loss of grease has been found in most casesto check results obtained lay-weigh ing'the amount of grease "applied tothe bearing and tie-'- ter'miniti'g 'the loss by removing and weighing-thez'ig'reas'e re'main'in'g'in the bearing followingthe test. When the gfa's'e is totin'dto' emulsify 'badly' with water the amount of grease left in the hearing at the end of the testis more accurately determine'd"byi'efi1dving thetgrease as with a solvent-"and vaporizing" wa er" and solvent from the -remoVd -g'r'ease before wei'ghing.

--The following examples illustrate theflinipo'r'tant aspects ofthis invention. 1 a

EfdniPl-I Atypical sodium"soap grease isprepared-from the;

following-ingredients:

Grams Tallow fatty acids ("(60 Tallow f 319 Aqueous Naon 50% 2'16-, Mineral lubricating Gil 39 2" Oxidation inhibitor grams o'f dubrb cating oil and after ineIti-tig arid rh-iidng'tat f to low in xample I the aqueous NaOH is added slowly with stirring. When the addition of caustic is complete the temperature ofthe batch is increased to about 260-270 F. to effect reaction between the soap stock and the caustic. About onehalf of the remaining lubricating oil is then added slowly and mixed into the batch while ,gradually increasing the temperature to about 320 F. to' complete saponification. When this temperature' has been reached-"the"remainder of the oil is added-slowly whilestirring and during this addition the batch is cooled. When the temperature reaches" 200 250 'Fgthe' antioxidant isadded. Cooling and mixing is continued until the temperature reaches about ISO-160 F. and the batch is then drawn.

The above grease" has the followingchmacteristics:

ASTM worked penetration at 77 F 280 Dropping point A STM,-F 360 Sodium soap, percent by weight 15 Example' ll oil Comp-say, is added J and stirring continued for 30 minutes. The productis cooled with-slow-stirring.

' Example III -Aigrease is ipre'pared according to the method outlined in Example 1 except that following s aponification and addition of one-half the lubricating oil, .grams 2%- By weight-- of. the' total bat chi of Paricin 28s is added. This'inat'erial is described -in;Example--II. This grease is; substantially the same-as "the product of Example I wits-regard "to consistency, meltingpoint and percent P- 7 Example IV A4000 gram portion cr me-grease produced in Example I -'is heated in a grease-kettle with =stir'ring :to "a temperature-of 300 Fi'a'rfdtoit-isadded20'grams'of an amide product obtaine'd' by reactingchernically equivalent amountsof'ipropyl amine with 1 2 hydr'oxy stearic acid underdehydratingconditions as described hereinabove.

Thisvproduct is considered to-be N-propyl IZ-hydro'xysteer-amide;

' 'Exam le V grease is prepareii following. the method outlined "except thata'ft'er' completion (it-the neutrali Zati6n"afidfafter"addingfibout one-half -of the oil, as gfattis'of the amide prodt'lctides'cribed in Example is added e"pfoduct;grase' is substantially.identical in pidduc'tbf Example :1.

i 7 Example VI )8 300 graniportionfof thegrease produced in :Ex

t-p'iitratiou, nielting point and'pefcent soap with the :Example repeated usingthediamide product ob tainted- -byla tifiiighydfoiiy arachi iie (lid "with 'bulylfle "diatnine implace of tlie' a'mide' described:ia that xainple.

' Example? Afgiaijseis. prepared according to l ixamplel using the i clieni'ically"euivalent--ainount of I- Z-hydmxy I stearic acid qnivalent proportions Example XI To 500 grams of the grease produced in Example IX isadded 15 grams of Paricin and the mixture heated and stirred to' a temperature of 290 -F. Cooling 18' then effected while stirring.

Example XII To 500 grams of the grease produced in Example IX is added 25 grams of the product obtained by reacting 12-keto stearic acid with a chemically equivalent amount of octyl amine. The reaction product containing as a major ingredient N-octyl-12-keto-stearamide is added after heating the grease to 270 F. and the resulting mixture then cooled with stirring.

Example XIII A sodium stearate grease containing about 13.5% soap is prepared from the following ingredients:

Grams Stearic acid 30 Sodium hydroxide 4.8 Paricin 285 4 460 oil 200 This is a naphthemc oil having a V. I. of 28 and a viscosity at 100 F. of 600 SSU.

The stearic acid and a small amount of oil is heated to 140 F. and the caustic added. After heating to 260 F. approximately half the oil is added as the batch temperature is gradually increased. At a temperature of 290 F. the diamide, Paricin 285, is added and the heating continued to 220 F. The remainder of the oil is added as the batch cools. The product has a penetration of 153 at 77 F.

Results of bearing tests to determine water resistance of the greases of the above examples are shown in the following table.

Percent Water Loss Amide Product Bearing Test Product of Example N 0.

Reaction Product ot- Percent 100 F. 180 F.

by Wt.

I I II Ethylene diamine+12-hy- 2. 6 18. 5 67. 5

droxy stearic acid. III do 2. 6 19 56 IV Propyl amine+12-hydroxy 2. 0 25 61 stearic acid. do 2. 0 25 63 1,5-diamino pentane+12- 3. 0 22 59 keto stearic acid. Ethylene diamine+hy- 3. 0 19 55 droxy palmitlc acid. Butylene diamine+hy- 8. 0 18 63 droxy arachidlc acid. 100 Ethylene diamine+12-hy- 3 20 60 droxy stearic acid. XI do 3. 0 5 35 XII 0ctylamine+12-keto ste- 5.0 5 28 aric acid. XIII Ethylene dlamine-l-lZ-hy- 1. 7 7. 5 45. 5

droxy stearic acid.

In the above table it will be observed that the products of Examples I and IX are ordinary sodium soap greases without added amides. Example I grease is made with tallow and tallow fatty acids and thus contains saturated and unsaturated fatty acid soaps and Example IX grease is made with 12-hydroxy stearic acid. Both of these products were completely washed from the bearing at 100 F.

amass fourth-of any of these greases is washed from the bear ing at F. and even at F. a good portion of the grease remains in thebearing.

Greases of Examples X, X] and XII are sodium 12- hydroxy stearate greases of the type produced in Example IX but containing amide product. These products show even greater resistance to water than those based on sodium soaps of tallow and tallow fatty acids.

The grease of Example XIII being made from stearic acid, a saturated acid and containing an amide product is similar to the preceding group of greases in water resistance.

It is to be noted that the bearing test is very severe compared with conditions encountered in ordinary service even where water or moist conditions are encountered so that even though some grease is washed from the bearing in the above test these greases containing amide product are successfully used in service where the ordinary sodium soap greases have been found to fail in a relatively short period of time.

As would be understood by one skilled in the art when the term sodium soap grease is used it is meant to include those products consisting essentially of lubricating oil containing thickening proportions of sodium soap with or without added oxidation inhibitors.

The foregoing description and examples are illustrative of the invention but are not to be taken as limiting the invention since many variations may be made without departing from the spirit and the scope of the following claims.

I claim:

1. A water resistant sodium soap grease consisting essentially of mineral lubricating oil and thickening proportions of sodium soap and containing between about 0.5% and about 5% of an amide product obtained by reacting under dehydrating conditions an amine selected from the class consisting of alkylene diamines having 2-8 carbons per molecule and alkyl monoamines having -1 to 10 carbon atoms per molecule with a fatty acid selected from the class consisting of hydroxy and keto fatty acids having 12 to 22 carbon atoms per molecule.

2. A water resistant sodium soap grease consisting essentially of mineral lubricating oil and thickening proportions of sodium soap and containing between about 0.5 and about 5% of an amide product selected from the class consisting of (1) diamides having the formula H 0 I ll in which R is a fatty acid radical of 12 to 20 carbon atoms having at least one substituent of the class consisting of hydroxyl and ketone substituents and R is the bivalent hydrocarbon portion of the alkylene diamine and (2), monoamides having the formula in which R is the same as R in the diamide formula and R" is a saturated alkyl radical of 1 to 10 carbon atoms.

3. A grease according to claim 1 in which said amide product is a diamide obtained by reacting ethylene diamine with 12-hydroxy stearic acid.

4. A grease according to claim 1 in which said amide product is a diamide obtained by reacting butylene diamine with lz-hydroxy stearic acid.