US2470537A

US2470537A - Mineral oil compositions

Info

Publication number: US2470537A
Application number: US757325A
Authority: US
Inventors: Stanley P Waugh
Original assignee: TIDE WATER ASSOCIATED OIL COMP
Current assignee: TIDE WATER ASSOCIATED OIL Co; TIDE WATER ASSOCIATED OIL COMP
Priority date: 1947-06-26
Filing date: 1947-06-26
Publication date: 1949-05-17
Anticipated expiration: 1966-05-17

Description

UNITED STATES PATENT OFFICE MINERAL OIL COMPOSITIONS Stanley P. Waugh, Westiield, N. 1., designer to Tide Water Associated Oil Company, Bayo N. 1., a corporation of Delaware No Drawing. Application June 26, 1947, Serial No. 757,325

7 Claims. (Cl. 25%) The present invention relates to improved mineral oil compositions, and, more particularly, to mineral oil compositions having improved performance characteristics. Although the novel compositions, as embodied herein, flnd utility for many usages, they are particularly adapted for use as lubricants, and especially for lubricating of engines operated under wet conditions, as for example, the wick-feed type of reciprocating marine engines. Hence, for purposes of illustration, the description of my invention, as is set forth hereinafter, is described in its adaptability to mineral oil compositions especially suitable for use in lubricating of marine engines of the foregoing type.

It is well-known to those skilled in the art that lubricating compositions for marine engines, e. g., wick-feed type reciprocating engines, should desirably possess certain essential characteristics for optimum performance. In particular, such compositions should not only possess certain physical characteristics, including viscosity, pour point, and the like, of desired values, but should wick-feed satisfactorily, readily emulsify with water (such as condensate formed during operation of the engine) and aqueous salt solutions, and in emulsified form, should possess good adhering characteristics to metal surfaces. For most purposes, mineral oils or fractions'thereof do not possess all of the aforedescribed desired characteristics, and hence, it is common practice, in providing suitable mineral oil base compositions for such usage, to blend mineral oils with bodied fatty oils. In general, compositions now in wide use commercially comprise a suitable mineral oil base stock having dissolved therein a substantial amount of a blown fatty oil, e. g., from about to 20%, and for the most part, at least about 15% by weight of the blown fatty oil. Use of blown fatty oils in such substantial proportional amounts has been found necessary for modification of suitable mineral oil base stocks to provide compounded compositions having the aforedescribed desired properties. More specifically, suitable examples of such lubricating compositions are the compounded mineral oils meeting the specification requirements of Bureau of Ships, Pamphlet N. B. S. 431, Oil, Lubricating Engines (Marine), compounded Navy Symbol 4065, relating to compositions having a viscosity (Saybolt) of 65-80 seconds at 210 F., a pour point not above 35 F., and suitable for lubrication of marine engines (wick-feed) and bearings and thrust bearings of auxiliary deck machinery. In brief, a composition meeting the foregoing speci- -2 flcation comprises a suitable mineral oil base stock having dissolved therein about 15-20% by weight of a suitable bodied fatty oil, e. g., blown rapeseed oil.

Although substantially high proportional amounts of blown fatty oils have been found necessary to desirably modify mineral oil base stocks for satisfactory performance thereof in marine engine lubrication, use of such large proportional amounts of blown fatty oils often impart certain objectional characteristics to the compounded composition. For example, blown fatty oils tend to decompose at elevated temperatures with production of charred or gummy materials and hence, deleteriously affect performance of the compounded composition at elevated temperatures; furthermore, blown fatty oils generally contain a considerable amount of free fatty acids, which tend to enhance corrosion of metal parts in contact with the composition, and additionally, depending upon the degree to which the blown fatty oils have been oxidized and/or polymerized, they tend to form oil-insoluble materials, probably due to continuing oxidation and/or polymerization of the bodied oils. It is highly desirable, therefore, apart from economic reasons, to employ bodied fatty oils in the minimum amount required to modify the mineral'oil base stock and provide blended compositions having the aforedescribed desired characteristics. As described hereinbefore; substantial amounts of bodied fatty oils, e. g., at least about 15% by weight, are generally employed so as to desirably modify the mineral oil base stocks, and by use of such large proportional amounts, the compounded compositions usually possess the hereinbefore described objectionable features resulting from' the use of high concentrations of bodied fatty oils in the compositions.

The present invention is based on the discovery that by incorporating certain substances, as described more fully hereinafter, into a suitable mineral oil base stock, the concentration of blown fatty oil employed can be materially decreased, as compared to heretofore used compositions, and yet provide a compounded composition highly effective for use as a lubricant, and particularly for lubrication of marine engines operated under wet conditions, e. g., wick-feed type reciprocating engines. Due to the marked decrease in concentration of bodied fatty oils that may be used by practicing this invention, and yet obtain desired results, with elimination of objectionable features associated with previously employed compositions,

cating composition by incorporating the two foregoing described hexitol anhydride derivatives into a suitable mineral oil base stock containing a concentration of blown fatty oil insuflicient by itself to modify the mineral oil to the extent required for highly satisfactory performance in marine engine lubrication. For example, whereas lubricating oils heretofore employed essentially contained a substantial concentration of blow fatty oil, e. g., about by weight, the present invention embodies compounded mineral oil compositions that are at least equal, and under some circumstances, actually superior in performance thereto even though the bodied fatty oil content of the novel compositions is markedly less than 15%, e. g., as low as 3.0% or even as low as 1.0% by weight, based on the weight of mineral oil. Compositions prepared in accordance with this invention and containing 1.0% by weight by blown rapeseed oil have provided excellent results under actual test in lubricating of wick-feed reciprocating engines in harbor craft.

In preparing the novel compositions embodied herein, the components thereof may be simply blended to provide a solution using heat, agitation and/or other suitable means to expedite solution. In preferred embodiment, the novel compositions are prepared by adding the blown fatty oil and the two component additives to a. suitable mineral oil base stock, and heating the mixture, such as to about 120 F., with agitation to expedite solution. The additive may be added as a combination of a partial ester of a hexitol anhydride and a polyoxyalkylene derivative of a hexitol anhydride partial ester, or these components may be individually added, highly satisfactory results being obtained irrespective of the manner of incorporating these components into the mineral oil base stock.

As embodied herein, the novel compositions comprise the essential use in combination of a suitable mineral oil base stock, a blown fatty oil, a partial ester of a hexitol anhydride, and a polyoxyalkylene derivative of hexitol anhydride partial esters. Thus; whereas the use of the foregoing components in combination provide the desired results, I have found that under certain circumstances, compositions similar thereto except that an essential ingredient has not been used do not provide the highly effective results embodied herein. For example, compositions containing a suitable mineral oil base stock, a blown fatty oil and only one of the two aforedescribed hexitol anhydride derivatives usually provides a composition inferior in solubility and/or emulsifying characteristics. Similarly, compositions containing a suitable mineral oil base stock and the two component additive, but devoid of a blown fatty oil, are usually inferior in solubility and/or emulsifying characteristics, the inferior-solubility characteristics apparently being due to the absence of blown fatty oil in the composition.

The oil used as the base stock in preparing my novel compositions may be derived from any of l the available crude oils, such as paraflinic crudes,

naphthenic base crudes, mixed base crudes, and fractions or blends of such crudes. The base stock is preferably a mineral oil of high quality and of desired viscosity, pour point, gravity, etc., for intended usage. Although it is not intended that my invention be limited thereto, as suitable mineral oil stocks derived from various crudes may be employed, I have for purpose of illustration set forth hereinafter asbase stock A and base stock B examples of base stocks derived from naphthenic crude that may suitably be employed in practicing this invention:

Base Stock Base Stock A B API Gravity l6. 0 18. 6-22. 0 Pour Point F 15 0 Viscosity at 210 F. (Saybolt Universal Seconds) 80-90 47-49 In preparing my novel compositions, I preferv ably employ blown rapeseed oil as the blown fatty oil, although other blown fatty oils of the semidrying type may be used. Thus, for example, blown peanut oil, blown mustard seed oil, certain fractions of fish oils, and similar fatty oils may be employed. As is known to those skilled in the art, such oils are usually prepared by blowing semi-drying fatty oils with air whereby the oils are polymerized and/or oxidized to form thehighly viscous materials known as blown fatty oils.

As stated hereinbefore, the essential components of my novel compositions that enable use of materially reduced concentrations of blown fatty oils comprise a suitable mineral oil base stock, a blown fatty oil, a partial ester of a hexitol anhydride, more preferably a fatty acid partial ester of hexitol anhydride, and a polyoxyalkylene derivative of hexitol anhydride partial esters. For purposes of convenience, the partial esters of hexitol anhydrides are hereinafter referred to as group A compounds, and the polyoxyalkylene derivatives of hexitol anhydride partial esters as group B compounds. The hexitoi anhydrides, as embodied herein, include the sorbitans and sorbides, mannitans and mannides. In preferred embodiment, the partial esters of the hexitol anhydrides are obtained by esterifyihg the hexitol anhydrides with fatty acids containing at least twelve carbon atoms to form the group A compounds. As compared to group A compounds, the group 3 compounds are characterized in that the free hydroxyls of the hexitol anhydride partial esters are modified by reaction with alkylene oxide whereby the group 3 compounds have a higher ratio of ether oxygen to hydrowl; that is, the group B compounds comprise the hydroxypolyoxyethylene ethers of the group A partial esters. Such ethers can be prepared by methods known to those skilled in the art, as for example, by etherifying the partial ester by heating with a preformed polyethylene glycol or by reacting the ester with ethylene oxide in the presence of a suitable catalyst. With reference to the group A compounds, I prefer to employ the partial esters of sorbitan, including the mon'olaurate, monopalmitate, monostearate, trioleate, and the like, esters of sorbitan. With reference to the group 13 compounds, I prefer to employ the polyoxyalkylene derivatives of the sorbitan partial esters, as enumerated hereinbefore, the hydroxy polyoxyalkylene ether of sorbitan monooleate being a highly suitable example thereof.

In order to further describe my invention, several compositions are set forth hereinafter that were prepared and tested in accordance with performance requirements as described in bureau of Ships N. B. S. 431, Navy Symbol 4.065, relating to lubrication of reciprocating-marine engines of the wick-feed type. Apart from certain requirements relating to composition, physical characteristics, and the like, the specification contains a wickteed test and an emulsion test that must be met by a composition considered satisfactory under the specification. The wick-feed test is set forth as method 200.1 in Federal Specification W-L-lill-C and performance thereunder indi cates the wick-feeding characteristics of the oil under test by measuring the flow of oil by wicking action over prescribed time intervals. In order for a marine engine oil-of the type falling within the specifications to meet the wick-feed test, the oil composition should retain 30% flow at the end of 14 days under the conditions of the test procedure. With reference to the emulsion test under the specification, a given amount ofthe test composition is mixed with an equal volume of distilled or salt water (1% NaCl) at 130 F. to form an emulsion, and the emulsion thus formed allowed to stand for minutes. In order to satisfactorily pass the test, the oil should remain emulsified for the 00-minute period.

. Percentageby Weight Composi- Composi- Composition 1 tion 2 tion 3 Base Stock A 58. 0 50.0 50. 0 Base Stock 13 32.0 47. 0 47. 7 Blown Rapeseed Oil 10. 0 3.0 2.0 Sorbitan Trioleata. 0. l Hydroxy Polyoxyalkylene ether of Sorbltan Monocleate 1 0. 15

1 An oily liquid at 0., having a viscosity of 400-600 cp. at 25 0.. and a specific gravity of 1.00 to 1.05.

The foregoing compositions, on being subjected to the aforedescribed emulsion test, gave the following results: both composition 1 containing 10 by weight of blown rapeseed oil and composition 2 containing 3% of the blown-oil, but devoid of the hexitol anhydride derivatives, failed to pass the emulsion test in that oil separation had occurred before conclusion of the 60-minute test period. However, composition 3 containing only 2% of blownrapeseed oil and a minor amount of which did not contain the afo'redescribed two derivatives of sorbitan. Moreover, the emulsion formed by composition 3 was more dense than that of the other two compositions, indicating that more complete water dispersion occurred in composition 3 which is a desired characteristic for lubricating compositions of this type; addi tionally, the emulsion of composition 3 indicated superior adhesiveness to metal surfaces under lubrication.

In view of the results of the foregoing tests, it is clearly evident that use of a minor amount of the two component additive enables the production of highly suitable lubricating oils without necessity of employing the substantially large proportional amounts of blown fatty oils heretofore found essential for suitable performance em= bodied by the requirements of specification, Navy Symbol 4065. For example, whereas mineral oils 7 containing 10% by weight of blown rapeseed oil did not pass the specification requirements, a composition (No. 3) containing only 2% of the blown oil and minor amounts of the two hexitol anhydride derivatives satisfactorily passed the specification requirements as to performance, the superior performance being due to the presence of only 0.3% by weight as the sum of the hexitol anhydride derivatives. Not only does the present invention provide for a material reduction in the concentration of blown fatty oil that may be employed in the lubricating compositions, but additionally, advantages accrue to such compositions in that the amount therein of objectionable free fatty acids normally present in blown fatty oils is correspondingly reduced. For example, blown rapeseed oils usually contain about 0 to 7% of free fatty acids, and in some cases up to about 9%, whereupon compounded mineral oils containing about 15% of bodied rapeseed oil contain about 1% of free fatty acids. However, by em ploying the present invention, satisfactory compositions are prepared that need not contain more than 2 or 3%, or even not more than about 1% of the blown oil, in which case the free fatty acid concentration of the compounded oil is reduced to a negligible amount.

Example If Additional compositions, as embodied herein, were prepared employing proportional amounts of ingredients as set forth below, and subjected to the tests employed with the compositions of Example I. In each case, the compositions performed satisfactorily in a manner similar to composition 3 in Example I.

each of the two sorbitan derivatives passed the test in that no oil separation occurred before termination of the test period.

The foregoing compositions were also subjected to the wick-feed test as aforedescribed and the performance of composition 3 thereunder was 76 oleate; similar compositions except that only one 0! these sorbitan derivatives is employed, or when the composition contains both sorbitan derivatives but is devoid of blown rapeseed oil, exhibit inferior performance either in solubility characteristics, emulsifying capacity, or both. Thus, a mineral oil base containing 3% of blown rapeseed oil and 0.5% of either sorbitan trioleate or the polyoxyalkylene derivative of sorbitan monooleate usually exhibits inferior emulsifying or solubility characteristics; furthermore, a base mineral oil stock containing 0.5% o! sorbitan trioleate and 0.5% of the polyoxyalkylene derivative of sorbitan monooleate, but devoid of bodied rapeseed oil generally exhibits unsatisfactory solubility characteristics. Accordingly, as stated hereinbefore, the improved lubricating compositions as embodied herein are obtained by using in combination the More-described ingredients comprising a suitable mineral oil base stock, a bodied fatty oil, 8. fatty acid partial ester of a hexitol anhydride, and a polyoxyalkylene derivative of hexitoi anhydride partial fatty esters.

Although in the foregoing examples certain concentrations have been set forth for the cornbination oi ingredients employed in preparing my novel compositions, such concentrations have been set forth for illustrative purposes, and are not to be considered limitative. As will be appreciated by those skilled in the art, the concen trations of ingredients may be varied depending on factors such as solubility characteristics, the conditions under which the compounded composi tion is to be used, the type and composition or specific ingredients employed, and the like. In general, however, compounded compositions as embodied herein usually comprise a major proportional amount 02 a suitable mineral oil base stock containing up to about 15% of a blown fatty oil, and minor, but effective, amounts of each or. the hexitol anhyclricie derivatives as described hereinbefore. In a preferred embodiment, particularly for lubricating of reciprocating marine engines, the compounded composition comprises at least about 85% by weight of a suitable mineral oil base, up to about 1.0% of each of the two types of hexitol anhyclride derivatives, and the balance a blown fatty oil. Although the amount of each or these derivatives may exceed about 1.0% by weight of the compounded composition without apparent deleterious efiects, such higher amounts are not usually necessary, as from about 0.05 to about 1.0% of each derivative has been found to provide highly satisfactory results. Furthermore, although the two hexitol anhydride derivatives may be employed in other than sub stantially equal amounts by weight, as long as an efiective amount of each derivative is employed, it is preferred that these derivatives be used in substantlally equal amounts by weight as usage in this manner provides more efiective results in performance, solubility, emulsifying characteristics, and the like. A particularly suitable ex ample of a composition falling within the foregoing preferred ranges of ingredient concentrations is illustrated by the composition hereinbefore designated as composition 3, containing about 97% of mineral oil, about 0.15% of sorbitan trloleate, about 0.15% of the hydroxy-polyoxyalkylene ether of sorbitan monooleate, and the balance substantially all blown rapeseed oil.

Although the present invention has been described in conjunction with certain preferred embodiments thereof, those skilled in the art will readily recognize that variations and modifications can be made. Such variations and modifications are to be considered to be within the purview of th specification and the scope of the appended claims.

I claim:

. i. A lubricating composition suitable for use under aqueous conditions and characterized by forming upon admixture with water a water-inoil emulsion having lubricating properties which comprises a mineral oil in major proportional amount having dissolved therein (a) at least about 1% but less than about 15% by weight of a blown semi-drying fatty oil and (b) about 0.05 to about 1.0% by weight of (1) a hexitol anhydride partially esterifled with a fatty acid of at least 12 carbon atoms and (2) about 0.05 to about 1.0% by weight of a polyoxyaliwlene derivative of a hexitol anhydride partially esterified with a fatty acid of at least 12 carbon atoms.

2. A composition, as defined in claim 1, where in the partial ester of a hexitol anhydride is sorbitan partially esterified with a fatty acid oi at least 12 carbon atoms.

3. A composition, as defined in claim 1, wherein the polyoxyalkylene derivative is a hydroxypolyoxyalkylene ether of a sorbitan partially esterified with a fatty acid of at least 12 carbon atoms.

e. A composition suitable for lubrication of marine engines under wet conditions and charnotarized by forming a water in-oil emulsion upon admixture with water comprising a mineral oil of lubricating grade in major proportional amount having dissolved therein; about i to 15% by weight of blown rapeseed oil, about 0.05 to 1.0% by weight of a hexitol anhydride partially esterified with a fatty acid of at least 12 carbon atoms and about 9.05 to 1.0% of a hydroxy-poly oxyalkylene ether of a hexitol anhydride partially esteriiiecl with a fatty acid or at least 12 carbon atoms.

5. A composition comprising a. mineral oil base stock in major proportional amount having dissolved therein about i. to 15% by weight of blown rapeseed oil, about [Hi5 to 1.0% of a sor bitan partially esterified with a fatty acid of at least 12 carbon atoms and about 0.05 to 1% of a hydroxy-polyoxyallrylene ether of a sorbitan partially esterified with a fatty acid of at least 12 carbon atoms.

6. A composition comprising a mineral oil in major proportional amount having dissolved therein about 1 to 15% by weight of blown rapeseed oil, about 0.05 to 1.0% or sorbitan trioleate and 0.05 to 1.0% of a polyoxyalkylene ether or sorbitan monooleate.

7. A composition comprising a mineral oil in major proportional amount having dissolved therein about 1.0 to 3.0% by weight of blown rapeseed oil, about 0.15% of sorbitan trioleate and about 0.15% of a hydroxy-polyoxyalkylene ether of sorbitan monooleate.

ST P. WAUGE.

REFERENCES @HCEIZZJ The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,231,167 Lazar Feb. 11, 1941 2,228,429 Wright Jan. 14, 194:1 2,398,193 Sharp Apr. 9, 1940 o'rnna REFERENCES "Atlas spans and Atlas Tweens." publication of Atlas Powder 00., publication date about November, 10%2.