US2262773A - Lubrication - Google Patents

Description

Federated Nov. 18, 1 941 wmucs'rron Bert H. Lincoln, Ponca City, Okla., and Alfred Henriksen, deceased, late of Ponca City, th., by John W. Wolfe, administrator de bonis non, Ponca City, Okla asslgnors, by mesne assignments, to The Lubri-Zol Development corporation, Cleveland, Ohio, a corporation of Delaware No Drawing. 7 Application March 19, 19:7,

Serial No. 131,960

'1 Claims. (01. 252-54) This application is a continuation in part of our co-pending application Serial No. 610,988, filed May 12, 1932 and application Serial No. 615,462, filed June 4, 1932.

invention relates, as indicated in my above-mentioned. co-pending application of which this is a continuation in part, to lubrication and more particularly to the improvement of those properties such as increased film strength, reduction in friction, reduction in wear, increased stability, etc.. which may be deficient in plain mineral lubrication oils, especially when employed for the purpose of lubricating under and vegetable oils during use have made them very unsatisfactory for general use, as well as uneconomic'al due to the expense of the fatty oilsand the quantities required.-

Mineral oils having low film strength allow seizure of the rubbing surfaces when, for'one reason or another, pressures are increased or the rubbing speed is slow.

It has been found that commercial stearic acid as found on the market and other saturated fatty acids, when blended with-mineral lubricatextreme conditions, such as those imposed by elevated temperatures, extreme pressures and th like.

- It is a principal object of our invention, therefore, to provide lubricating compositions and a method of lubricating characterized by the aforementioned improvements.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means? hereinafter fully described .and particularly pointed out in the claims, .the following description setting forth in detail certain approved combinations of ingredients embodying our invention, such disclosed means constituting,

however, but certain of various forms in which the principle of the invention maybe used.

Broadly stated, this invention comprises the discovery that lubricating compositions of improved characteristics may be produced by the addition to lubricating oils, such as mineral ii, of various amounts of halogenated organic aci Further objects of this invention are to provide a lubricant with high oiliness character and high film strength without introducing the objectionable features of lubricating oil sludging, gumming, rancid odor and perceptible corrosion.

The application of this invention realizes these objects very economically.

Under conditions of boundary lubrication the viscosity of the lubricant plays only a minor part in lubrication. With slow speeds and heavyloads contributing to boundary lubrication, the lubricant to be efiicient must have a high degree of oiliness or unctuosity and must have a high" film strength. The very best mineral oils are,

chines lubricated 'with mineral oilsonly. For

these particular duties lubricating engineers have used animal and vegetable oils with some chin'wlth a 40% lead disc.

ing oil, will greatly reduce the coefiicient of friction. As an example, a good 'grade mineral oil had'a coefficient of friction of 0.135 to 0.140 when tested on the Herschel friction testing ma- (The Herschel friction testing machine is a development by Dr. W. H. Herschel of, the U. S. Bureau of Standards.) when 0.5% commercial stearic acid was added to the above mineral oil, it had a coefficient of friction of only 0.055. Thus,"by adding a very small amount of stearic acid, the coefficient of friction was only 39 to 41% v as' great as with the original as.

The meltingpoint of commercial stearic acid is around 100-170 F., depending upon the impurities present in the commercial acid. (These impurities do not affect the value of this invention, it being found that any of the commercial stearic acids are suitable.) Stearic acid is completely soluble in mineral oil at high temperatures, but due to its high melting point, the

stearic acid starts solidifying as the temperature 'goes below say 100 F. and at low temperatures, say around 15 to 30 R, will in. time settle out of the solution. This is a common characteristic of the saturated fatty acids of high melting point, which'requires their use in warm weather 1 and prohibits storage and use of lubricants prepared in this manner during cold weather. with this knowledge, the use of saturated fatty acids in mineral oil may be economically and efiiclently applied in a number of places.

It has been found, however, that the solubility and film strength of atty acids can be greatly improved by halogenation. The halogenated fatty acids will remain in solution over long time storage during cold weather and will not cause sludging of the lubricant, gumming or other objectionable features. Addition of halogen to the fatty acid molecule lowers the' melting-point and accomplishes this very beneficial result and makes them available for economical use 'under any kind of temperature conditions.

mbutthechangesoccurringintheanimal' As an example of b nary commercial used in small quantities.

- stearic acid (a saturated acid) with-a melting point around 120140 F. was chlorinated .direct with chlorine until the chlorinated product had a melting point of 62 F. Excess free chlorine and hydrochloric acid are removed by any of the ordinary means and the chlorinated product added to mineral oil lubricants in small quantitles. The poorer the quality of the original lubricating oil, the more the chlorinated acid required. The Herschel friction tssting machine was used to determine theincreased oiliness. The original mineral oil showed a coeificient of friction of 0.135 to 0.140%. Chlorinated stearic acid was added in quantities of from .05% to .5% with the following results:

Amt. oi chlor. stearic acid added to mineral lubricant 0.135 to 0.140 0.072 to 0.077 0.070 to 0.075 0.070 to 0.075 0.070 120 .075

Original mineral lubricant; .05

face pressures which may beconsiderably in excess of 10,000 pounds per square inch. Such pressures are now commonly encountered in hyengines, and are becoming more prevalent with upon the metallic surfaces.

advances in modern machine design.

It is believed that ,the halogenated organic acids react chemically or physico-chemically with the metallic surfaces to form a non-fluxing surface which willnot seize or score. This invention is not intended to be limited, however, by any particular theory or explanation of the action When used in conjunction with a; lubricant an amount from about 0.1% and sometimes less to about 20% of the addition agent, based on the amount of oil, and often from about 0.5% to about 2% or less is all that is requiredto render the finished lubricant eflicient under conditions of extreme pressure. In the case of gear lubri- Another sample of commercial stearic acid was chlorinated until the chlor acid had -a melting point of 9 F. This product was added to the same mineral oil with the following results:

Both of the above examples clearly show that the maximum reduction in coeflicient of friction is obtained with small quantities of the chlor. fatty acid. In the case of the fatty acid chlorinated at 9 F. melting point, the coefficient of friction increased when the amount of acid added 45 reached 0.5%. As previously stated, with a poorer quality original mineral oil as much as 2% or more acid may be required to get the same reduction in coeflicient of friction.

It has been found that unsaturated free fatty acids will reduce the coeflicient of friction when For example, 0.5% of oleicv acid in a mineral oil having an original coeflicient of friction of 0.135 to 0.140 gave a product with a coefllcient of friction of 0.055 to 0'.060. 55

Commercial olelc acid representing the field of unsaturated fatty' acids was chlorinated to partial saturation and suflicient. chlorine added to pre-- vent acid sludging or polymerization of the unsaturated acid. This product, when added to a mineral lubricant having an original coeflicient of It is a particular object of this invention to pro,- vide safe and eflicient lubrication for relatively moving metallic surfaces acting with inter-sur- 7 .above, viz., about 0.1% to about 2%.

cants, for example, somewhat larger quantities,- from about 5% to, about 10%, may often be preferred, but ordinary crankcase oils generally require no more than the lesser quantities indicated When, however,- the particular use makes advisable a higher percentage of p the so-called addition agent, the halogenated organic acids may be employed with any such proportion of lubricating oil as may be required to afford the characteristics desired, It is, of course, obvious that generally only such amounts of the addition agent may be included as are soluble in the specified amount of oil. By the term "soluble? as herein used, we intend to indicate the ability toform not only true solutions but also any form of substantially permanently homogenous solution when incorporated in mineral oil. With most of the compounds there is usually little difliculty, especially if the incorporation is effected in the manner described in Cornell Patent No. 2,042,880,

and since quite small percentages often give remarkably improved results it' is seldom of extreme importance that the addition agents be oil-soluble in all proportions. Also, certain com pounds are of value as gelling or bodying agents when used in amounts greater than are strictly soluble; for example, certain compounds such-as halogenated acids of the type which contain an anthracene' nucleus and a plurality of side chains.

- friction of 0.135 to 0.140, gave the following rel molecule.

It is also desirable for many 'uses that the addition agent have a vapor pressure less than atmospheric at C. and where high operating temperatures are encountered as in the combustion chambers of internal combustion engines it is,

preferable that the addition agent have a vapor pressure less than atmospheric at C. L

All of the various halogens are efiective when employed in accordance with the present invention but chlorine is generally preferred inasmuch as it is the least expensive and one of the most used to provide effective addition agents in ac-s cordance with the present invention.

It should also be noted that two or more different halogens may be present-on .the same The brom-chlor compounds and the fluorinated chlorine or bromine compounds give especially satisfactory results.

amples of the halogenated carboxylic acids which may be employed in accordance with this invention:

Halogenated aliphatic acids (fatty acids):

Saturated, e. g.-

Halogenated lauric acid Halogenated palmitic acid Halogenated stearic acid Unsaturated, e. g.-

Halogenated acrylic acid Halogenated oleic acid- Halogenated linoleic acid Halogenated hypo aeic acid Straight chain, e. g.-,

Halogenated lauric acid Halogenated palmitic acid Halogenated stearic acid Halogenated oleic acid Side chain, e. g.

Halogenated iso-butyric acid Halogenated iso-caproic acid Halogenated meta crylic acid Long chain or more C atoms) e. g.--

Halogenated lauric acid Halogenated palmitic acid Halogenated stearic acid Halogenated oleic acid Short chain (less than 10 C-atoms) e. g.-

Halogenated acetic acid Halogenated propionic acid Halogenated butyric acid Halogenated caproic acid Halogenated acrylic acid Hydroxy aliphatic acids, e. g.

Halogenated lactic acid Halogenated glyceric acid Halogenated mannitic acid Halogenated malic acid Halogenated saccharic acid Halogenated citric acid Halogenated ricin-oleic' acid Aromatic substituted fatty acids:

Halogenated mandelic acid Halogenated phenyl-lactic acid Halogenated phenyl-acetic acid Where the aromatic hydrocarbon is selected from the group of, benzene or its homologs- Halogenated phthalic acid Halogenated phenyl-acetic acid Halogenated tolyl-acetic acid Halogenated xenyl-acetic acid Halogenated phenyl-stearic acid Halogenated tolyl-lauric acid Halogenated xenyl-palmitic acid Halogenated cinnamic acid Where the aromatic hydrocarbon is selected from the group of naphthalene and its homologs Where the aromatic hydrocarbon is selected from the group of phenanthrene, anthracene, and their homologs Compounds where the aliphatic radicle has more carbon atoms than the aromatic radicle Where the compound contains a hydroxyl radicle-- (a) Attached to cle: Halogenated mandelic acid Halogenated phenyl lactic acid the. aliphatic radi- (b) Attached to the aromatic radicle: Halogenated hydroxy phenyl lactic acid I the halogen is attached- (a) To the aliphatic radicle (b) To the aromatic radicle (c) To both radicles When the halogen is attached to a carbon of the benzenoid ring structure it is especially stable and not readily hydrolysed.

To determine the film strength of lubricants under high pressure, two testing machines have been developed. One is called the Mougey machine and was perfected by Diz'H. G. Mougey of the General Motors Corporation and has been described by the inventor in various literature. The other machine is known as the Timken machine and was developed by the Timken Roller Where Bearing Company, which has also been described in the literature. The primary object of these machines is to give very high pressure per unit area of rubbing surfaces under conditions resembling those found in commercial use but probably a little more severe. The lubricant is placed between the friction surfaces and usedwith increasing pressure or load at the friction point until seizure of the metal surfaces occurs. With the Mougey machine the pressure or load may be held constant and one may determine the time required for seizure of the metal surfaces. By the use of these machines itis easy to compare the film strength of two oils.

Using the Mougey machine a good grade mineral oil allowed seizure of the friction surfaces in 30 minutes with a load of 20004? per square inch. Using another sample of the same mineral oil blended with 0.5% of chlorstearic acid of 9 ,F. melting point and operating the Mougey machine at 2000 pounds per square inch pressure, there were no signs of seizure after a period of 45 minutes, providing a decided superiority of film strength in the lubricant blended with chlorstearic acid. With higher pressures, larger quantitles of the chlorstearic acid should be used-as much as 5% or more being required.

Using the Timken machine with the original lubricant seizure of metal surfaces occurred when 18.2 pound weight had been added, which represent a pressure of approximately 10,500 pounds per square inch. To a sample of this same lubricant 0.25% of chlorstearic acid of 9 F. cold test was added, and when this blended lubricant was used in the Timken machine seizure did not occur until a 32.2 pound weight had been added representing a pressure of approximately 19,000

pounds per square inch.

Repeating the test on the Timken machine with the same original lubricant containing 0.5% of chlorstearic acid of 9 F. melting point, metal seizure did not occur until 38.0 pound weights had been added, which represents a pressure of approximately 22,000 pounds per square inch. Thus, by adding 0.5% of the product of this invention to a high quality lubricant, its film strength is more than'doubled.

The above tests clearly demonstrate the econo my and efilciency of the process and show that by this invention it is possible to prepare a lubricant for practically any duty by either varying.

the percentage of product blended and/or varying the degree of halogenation of the product to be blended.

' It has also been found that lubricants prepared halogenated oleic acid by this invention do not lose their oiliness c acteristics when diluted with small amounts of unburned mot'or fuel, making this type of lubricant of unusual value in actual commercial lubri-' hours at 392 F., the

2,262,778 proportion of a halogenated aromatic substituted I number of 91.6 while the same oil with 0.5% of gave a sludging number of 72.4 or a reduction in sludging number of 19.2.

Othe modes of applying the principle of the inventi 11 may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.

We therefore particularly point out and distinctly claim as our invention:

1. A lubricating composition comprising a major proportion oflubricating oil and a minor proportion of a halogenatedaromatic substituted fatty acid.

2. A lubricating composition comprising a major proportion of lubricating oil and a minor aliphatic acid. i

3. A lubricating composition comprising a major proportion of lubricating mineral oil and a minor proportion of halogenated organic acid containing an aromatic group in the molecule.

4. A- lubricating composition comprising a major proportion" of lubricating mineral oil and a minor proportion of halogenated organic acid containing an aromatic group-in the molecule, which aromatic group is selected from the group I of benzene and its homologs. v

5. A lubricating composition comprising a major proportion of lubricating mineral oil and a minor proportion of a halogenated aromatic substituted fatty acid of the type in which a hydroxyl group is attached to a chain structure.

6. A lubricating composition comprising a major proportion of lubricating-oil and aminor proportion of a halogenated hydroxy aromatic acid. I A

7. A lubricating composition comprisinga major proportion of lubricating mineral oil and. a minor proportion of halogenated organic acid containing a benzenegroup in the molecule.

- 1 BERT H. LINCOLN.

v JOHN W. WOLFE, Administrator de boats non of the Estate of Alfred Henriksen Deceased.