US2397904A - Gun oil composition - Google Patents

Description

Patented Apr. 2, 1948 UN TE STATES PATENT orncs ammo;

GUN on. coMrosmoN tion of New York No Drawing. Application March 5, 1943, Serial No. 478.142

7 Claims. (CL 252-39) This invention relates to preservative lubricant compositions adapted for use in lubricating small arms and the like and in protecting the same from corrosion. It is concerned more particularly with the provision of a preservative gun oil composition composed of a lubricating oil and additives which composition is substantially neutral and has a very low pour point, and which does not precipitate crystalline bodies upon being cooled to very low temperature (e. g., to --50 F. and lower) Superior preservative lubricant compositions useful both for the lubrication and for the protection against corrosion of small arms over a wide range of temperatures including low temperatures of the order of --50 E. should have the following properties and characteristics:

Pour point Viscosity at 100 F 17 to 26 centistokes. Viscosity at 32 F- 132 to 160 centistokes.

Protection 100 hours min, in humidity cablnet at 100 F. and 100% relative humidity. Volatility from metal surfaces None. Film thickness Min. .0012 centimeters. Polar properties Distinct polar properties as determined when lubricant is spread on water. Immersion test Corrosion must not take place within 200 hours when cold rolled steel covered with the lubricant is immersed in tap water. Water Absorption---" Invisible films of condensed water on metal surfaces must be absorbed by the lubricant.

" Penetration Lubricant must be capable of spreading and penetrating over metal surfaces and into well fitted bearing surfaces.

Lubrication Lubricant must show a low coeihclent of friction and relatively high temperature breakdown when measured on the lubarome er.

Some but not all of the above-recited properties and characteristics. are possessed by a composition composed of lanolin (or wool grease), and

lecithin (or equivalent phosphatide) dissolved.

in a highly refined petroleum lubricating oil of low pour point. Thus, it has been found that when such a composition is'progressively cooled from normal room temperature to a low temperature at which small arms frequently have to be fired, crystalline bodies settle out of the composition whereby both the pour point and viscosit of the composition are very materially increased. Moreover, said composition is deficient in wetting properties toward metal surfaces and in lubricating 'properties' Also, said composition has an undesirably high acid number (due to the fact that both the wool grease and the lecithin are acidic to a degree), and is deficient in corrosion-preventing properties. I

Alkyl esters of said aliphatic carboxylic acids are described in U. 8. Patents Nos. 2,096,390 to Arthur W Burwell and Adolf Kempe and 2,385,733 to Arthur W. Burwell. I have discovered that the properties and characteristics of a gun oil composition of the kind Just described may very materially be improved by .the addition thereto of a small amount of a mixture of oil-- soluble lower alkyl (e. g., methyl or ethyl or propyl) esters of relatively high molecular weight aliphatic carboxyiic acids derived from the oxidation, by the Burwell process disclosed in U. S.

Patent No. 1,690,769 to Arthur W. Burwell, of a highly refined petroleum lubricating oil, preferably one which is substantially free from crystalline bodies, asphalts and unsaturated hydrocarbons, e, g., "Triton" oil. According to said Burwell process, oxidation products including relatively high molecular weight-aliphatic carboxylic acids are produced by contacting a gas containing free oxygen, at a superatmospheric' pressure, with a petroleum hydrocarbon mixture such as a distillate of lubricating grade, in the liquid phase and at an elevated temperature in excess of 199 C. and in the presence of a promoter of oxidation. I have found that the presence of a small amount of these lower alkyl esters of "A10! acids effects a solvent action both on the wool grease and on the lecithin, to the end that the latter do not crystallize out of the composition 'at low temperatures, e. g., at F., and at the drating the resulting product at elevated temperature and separating therefrom any bodies which may settle out of the dehydrated treated composition upon settling and cooling. Such cooling and settling may result in the precipitation (that is the settling out) of some (but by no means all) of the calcium soaps formed by the "liming"- treatment, which precipitable soaps if retained in the composition might depreciate the good functioning of the latter at very low temperatures.

'I'hisFlIming measure, which serves to convert to calcium soaps substantially all of the free acids contained therein (that is, the acids which normally are present in such wool grease and/or lecithin'and/or lower alkylesters oi "Alox acids") whereby the acid number of the composition is depressed to a desirable very low value (e. g., to not exceed 0.3), serves materially to improve the corrosion-inhibiting properties of the composition and to provide a gun oil? which remains brilliantly clear, and fully effective as a lubricant, at very low temperatures (e. g., at -50 F. an lower).

A specific composition falling within the scope and embodying the concepts of the present invention substantially consists of a solution, in a highly refined'p'etroleum lubricating oil having a pour point of --50 F., a viscosity at 100 F. of

from 17 to 20 centistokes and'a viscosity at 32 F. of from 132 to 160 centistokes, of the substantially neutral (i. e., not reactive with calcium hydroxide) components of about 5.0% by weight wool grease, about 4.35% methyl esters of acids derived from the oxidation of a highly refined petroleum lubricating oil free from crystalline bodies, asphalts and unsaturated hydrocarbons, and about 0.4% vegetable lecithin, together with a small, variable, amount (of the order of 1% by weight) of calcium soaps of acids originally brought into the composition by way of the ad-' ditives just mentioned. To this composition I may, and preferably do, add about 0.25% cal cium amyl phenate oxidation-retarding agent (or an equivalent amount of any other. known oilsoluble oxidation-retarding agent).

The composition may be prepared as follows: A concentrate ismade up from about 87 parts by weight of the aforesaid methyl esters of Alex acids, about 8 parts by weight of vegetable lecithin. (e. g., lecithin obtained from soy beans) and about parts by weight of the oxidationretarding agent. The concentrate is blended with the "diluent oil to the extent of about 5% by weight,about 5% by weight of wool grease is added, and the resulting blend is subjected to liming treatment. As will be well understood, a part only of the total amount of diluent oil may be used in preparing a primary blend, the resulting primary blend may then be limed ani thereafter the rest of the diluent oil incorpora ed.

In efiecting the liming treatment the solution of additives in oil is treated, at elevated tem-. perature (L -100 C.), with an excess of calcium hydroxide with thorough stirring, and the reaction mixture is dehydrated by heating (with stirring) to a temperature well above the boiling point of water, say, to a top temperature of about 160 C. Thereafter the dehydrated mixtureis cooled to about room temperature, e. g.,' to 23 C.,-and maintained in quiescent state for some time topermit the settling out of any insoluble material, and, after addition of filter-aide, finally is filtered. The settling and filtration removes I excess lime and any insoluble-calciumsoapsv :gun oil having a very low pour point. When it is cooled from room temperature to about 50 F. no crystalline bodies separate therefrom. Its distinct polar properties make for a tightly clinging film of the composition on a metal surface.

operable at very low temperatures,e. g., at --50 F. or lower without failure due to solidification of lubricant or lack of lubrication. Moreover, the composition satisfactorily resists breakdown at high temperatures.

It has been found that afilm coating or the preservative lubricant composition of the present invention over the surfaces of a firearm effectually protects the latter against corrosion over very extended periods (as during shipment of the firearm or during long-continued storage of the latter).

conventionally employed modes involving either the smearing of the firearm with thick layers of a heavy grease-like protective agent or the embeddingof the firearm in a body of the greaselike material. When the latter material was employed, the so-treated gun could-not be put to use until said material had beencompletely removed (a laborious task, customarily involving use of solvents) and the gun had been oiled with a proper lubricant. Such removal was especially diflicult in case the so-treated firearm had borne i ts coating over a long period (say, a year or thereabouts), because the prior art material upon aging underwent a change adjacent the metal surface, becor'ning gummy or resinous" and ad- ,hering very tenaciously to the metal.

In contradistinction to the prior art modes of protection, the present mode ofiers the advantages that (1 only thin films of the present composition are needed; (2) the composition does not undergo change upon aging; (3) the composition need not be removed before the firearm is put to use but rather constitutes per se a proper lubricant for the gun and its operating. parts. Accordingly, small arms so protected during shipment or storage may simply be taken out of their container, loaded and fired.

It is to be understood that it is within the scope of the present invention to make reasonable adjustments in the relative amounts. of additives employed in the gun oilcomposition and in the identities of the additives. As has been stated hereinbefore, the lower alkyl esters of Alex acids may be ethyl or propyl esters instead of the methyl esters specifically recited.

I claim:

1. A corrosion inhibiting lubricant composition for small arms and the like comprising a substantially neutral solution, in a highly refined petroleum lubricating oil of low pour point, of substantially neutral components of about 5 parts by weight of wool grease, about 0.4 part by weight of lecithin and about 4.35 parts by weight of methyl esters of high molecular weight saturated aliphatic acids derived from the oxidation of a lubricating oil, at superatmospheric pressure and elevated temperature in the presence of a promoter of oxidation, together with oil-soluble calcium soaps of acids normally present in such wool grease, lecithin and methyl esters and about 0.25 part by weight or calcium amyl phenate oxidation-retarding agent, the content of lubricatingoil in said composition being sumcient to bring the total to parts by weight.

- 2. A corrosion inhibiting lubricant composition v for small arms and the like comprising a substanabout 5 parts by weight of wool grease,about 0.4

a small arm lubricatedwith the composition is 76 9811- by-weight of lecithin and about 4.35 parts This mode of protecting said mechanism has several advantages over the heretofore pressure and elevated temperature in the 'p-res enceof a promoter of oxidation, together with oil-soluble calcium soaps of acids normally present in such wool grease, lecithin and methyl esters, and about 0.25 part by weight of calcium amyl phenate oxidation-retarding agent, thecontent of lubricating oil in said composition being suflicient to bring the totalto lOOjparts by weight.

3. In the process of preparing a preservative lubricantcomposition comprising a solution of about-% by weight of wool grease and about 0.4% by weight of lecithin in a highly refined petroleum lubricating oil oflow pour point, the improvement which consists in converting to oil-soluble calcium esters the calcium hydroxide-reactive constituents of the wool greasev and the lecithin by treating the solution with an excess or calcium hydroxide, whereby to form said oil-soluble calcium soaps, dehydrating the resulting reaction mixture, and removing insoluble components of the dehydrated reaction mixture from the latter, thereby retaining said oil-soluble calcium soaps in the solution.

4. In the process of preparing a corrosion inhibiting lubricant composition, for small arms and the like comprising a solution of wool grease and lecithin in a highly refined petroleum lubricating oil of low pour point, the improvement which consists in preventing the separation of crystalline bodies from the solution upon cooling the latter to a low temperature of the order of 50 F. by dissolving in said solution a mixture of oil-solublelower alkyl esters of high molecular weight saturated aliphatic acids derived from the liquid-phase controlled partial oxidation of a petroleum lubricating oil iraction substantially free from crystalline bodies, asphalts and unsaturated hydrocarbons, said oxidation being effected at superatmospheric pressure and elevated temperature in the presence or a promoter of oxidation, the amount of said lower alkyl esters mixture so added being about 4.35% by weight oi. the complete composition.

5. Process of producing a corrosion inhibiting lubricant composition having a low pour point which comprises preparing a solution, in a highly refined lubricatingoil having a pour point of the order of 50 F., of wool grease, lecithin and a mixture of lower alkyl esters or high molecular weight saturated aliphatic acids derivedi'rom the oxidation of a petroleum lubricating oil traction,

and about 0.4%, respectively, in the final solution and the amount of said lower alkyl esters mixture in said-solution 'being of the order oi 4.35% and at least sumcient to prevent the sep-- aration of crystalline bodies from said solution upon cooling of the latter to a low temperature of the order of 50' F., treating the solution, at elevated temperature with an excess of alkaline earth metal hydroxide, dehydrating the so-treated solution by further heating at a temperature materially above the boiling point of water, and separating from the dehydrated treated solution ingredients which are insoluble therein at room temperature.

6. Process of producing a corrosion inhibiting lubricant composition for small arms and the like having 'a low pour point which comprises preparing a mixture of about 87 parts by weight of methyl esters of high molecular weight saturated about 5 parts by weight of a calcium amyl phenate oxidation-retarding agent, blending the resulting mixture, together with an approximately equal amount of wool grease, with about twenty times its weight of a highly refined mineral lubricating oil having a low pour point of the order of F. whereby to form a solution, and liming the so-prepared solution to an acid number not greater than 0.3 by treating the same, at ele-, I

vated temperature, with an excess of calcium hydroxide, heating the resulting reactionmixture to a temperature in excess of the boiling point 01' water whereby to dehydrate the same, cooling the dehydrated reaction mixture substantially to room temperature, and separating from the reaction mixture material insoluble therein at such temperature.

7. A corrosion inhibiting lubricant composition for small arms and the like comprising a substantially neutral solution, in a highly refined petroleum lubricating oil of low pour point, oi substantially neutral components 01' about 5 parts by weight of wool grease, about 0.4 part by weight the amounts of wool grease and lecithin used being such as to give concentrations or about 5% or lecithin and about 4.35 parts by weight 01' lower 'alkyl esters of high molecular weight saturated aliphatic acids derived from the oxidation or a lubricating-oil ,at superatmospheric pressure and elevated temperature in the presence of a prometer of oxidation, together with oil-soluble calcium soaps of acids normally present in such wool grease, lecithin and methyl esters. the content or lubricating oil in said composition being suflicient to bring the total to parts by weight.

. JAMES E.'