US2346124A - Bullet lubrication - Google Patents

Description

Patented Apr. 4, W44:

2,346,124 BULLET LUBRICATION No Drawing.

4 Claims.

This invention relates to the lubrication of projectiles, and by way of illustration will be described as applied to the lubrication of projectiles for small arms ammunition.

Correct and proper lubrication of the projectiles of small arms ammunition, particularly those having lead surfaces, is an important factor in the maintenance not only of accuracy but of the proper functioning of'the firearm. The character of the friction between the bore surface and the surface of a lead projectile under rapid acceleration is such that unless the projectile is properly lubricated small quantities of lead may be sheared off and accumulate in the bore, impairing its accuracy and eventually dangerously reducing the bore diameter. n the other hand, an excess of lubricant is undesirable for the reason that under the high pressure prevailing within the gun barrel much of the excess is blown back into the chamber and the breech mechanism, especially in repeating and autoloading guns, where it congeals and accumulates. The accumulation of lubricant about the chamber may prevent the proper insertion of cartridges, and a similar accumulation in the breech mechanism frequently prevents the proper functioning of autoloading guns,

Application December 8, 1939, Serial No. 308,298

(0) Stability.--T'he film deposited and dried on the bullet must be of a thickness sufficient to contain the requisite amount of lubricant, .and be stable under adverse storage conditions. A separate stabilizing and thickening agent, such as a protective colloid, may be used.

particularly in cold weather. Further, cartridges having bullets which carry an excess of a soft surface lubricant are dirty and disagreeable to handle, and foreign materials readily adhere to their surface. Gritty materials thus adhering may cause irreparable damage to the bores of guns in which the cartridges are subsequently fired.

It is an object of the present invention to provide a lubricant and a method of its application such that bullets may be coated with a film which has a dry and non-adhesive surface and is of such character that it will become a lubricant under the conditions of projection of the bullet through a gun'bore. The material likewise protects the bullet itself from corrosion under conditions of high temperature and humidity.

More particularly, the invention contemplates the application of lubricants to projectiles by means of emulsions. Such emulsions may be applied in any desired manner, such as dipping, brushing or spraying. The essential features of such emulsions are:

(a) Lubricating capacity.-The lubricant is preferably one which is solid at ordinary temperatures. It must retain or acquire adequate lubricating properties under firing pressure.

(b) Emulsifier.To separate and maintain the lubricant in a state of fine division, an emulsifying agent is necessary.

(d) Film. -The lubricating material exists as a continuous, hard, homogeneous film, which is dry to touch and to which foreign matter does not readily adhere.

(e) Medium.The medium receiving the several ingredients may be water or other suitable fluid.

Thes essential features may be supplied by different ingredients introduced for one purpose only, or a single ingredient may perform two or more functions. For example, stabilizers are frequently unnecessary, and many emulsifiers are themselves film formers. Very satisfactory re- ,sults are secured with compositions comprising merely one or more lubricants emulsified in water with the aid of one or more emulsifiers some of which form films.

Suitabl lubricants include parafiin wax, ceresin wax, camauba wax, montan wax and its derivatives, ozokerite, 'glyceryl tristearate, Japan wax, bees wax, candelilla wax, bayberry wax, palm wax, spermaceti, Chinese insect wax, myrtle wax, higher alcohols and their derivatives, diglycol stearate, glycerol mono stearate, hallowax, Opal wax, cotton seed wax, flax wax, wool wax or lanolin, stearone, keto stearine, modified glyptals, and cellulose derivatives.

A wide variety of emulsifying agents may be used, among which may be mentioned various soaps, such as salts of long chain fatty acids, particularly stearic, palmitic, oleic and perilla oil acids, with alkalies or with various amines such as triethanolamine, diethanolamine, monoethanolamine, methylamine, 2-aminocyclohexanol, Trigamine, and trihydroxyethylamine stearate; sulphonated and sulphated products such as sulphonated castor oil or petroleum oils, sulphonated and sulphated fatty alcohols, and

' sulphonated naphthalenes; and such other emulsifying agents as lecithin, deacetylated chitin, n-octadecyltrimethylammonium bromide,

ammonium oleate, ammonium linoleate, polyvinyl alcohol, and diglycol laurate.

suitable film forming materials include cellulose derivatives such as nitrocellulose, cellulose acetate, ethyl cellulose, and benzyl cellulose; natural resins such as damar, shellac, congo, and kauri; synthetic resins such as acrylate and methacrylate, meta styrene, phenolaldehydes,

Sulphated fatty alcohol (A) vinyl, glyptal, keto-aldehyde, and ether resins; and asphaltic materials such as zilsonite.

Suitable protective colloids include such protein derivatives as casein, glue, albumen, and gelatinc; such natural resins and water soluble gums as arabic, tragacanth, madagascar, ghatti, shirag, and karaya; and such other materials as polyvinyl alcohols, weter soluble cellulose derivatives such as methyl'cellulose. cellulose glycollic acid, and amino cellulose such as deacetyh ated chitin.

In preparing the emulsion, the lubricating wax may first be melted and the emulsifying agent added and properly stirred into the melted wax. The water soluble ingredient may be dissolved in water, and the solution added slowly to the mixture of wax and emulsifying agent, proper dispersion and consistency of the emulsion being secured by agitation during and/or subsequent to bringing the various ingredients together. A pig- 20 ment may be added to secure any desired color.

Specific examples of such emulsions are as follows:

Per cent (arnauba wax l'arailin wax Steanne Casein )iStenol phosphate- Stem-i0 acid. Polyvinyl alcohol. Palmitlc acid Monoethanolaminmorax Sulphated fatty alco (C) Stearyl alcohol Stearyl trimethyl ammonium broide (20% paste) Sulphetcd fatty alcohol (B) Sulphatcd fatty alcohol A Olcate flakes (sodium oleate 88.2%) Borax Water Hydrogenated montan wax Stcaryl aleohoL--. Sulphated fatty coho] (B) Sulphatcd fatty alcohol (A) Oleate flakes (sodium oleate 88.2%) Borax ax Sulphated fatty al- M difi 31 "l' t'i' 0 e 8 YD a (RX-4732)..

Stearyl alcoho Oleic acid 'lriethanol amino. Borax Deacetylated ehltin Shellac Water.

In the above tables, stearyl alcohol is to be understood as a technical product containing a substantial proportion of stearyl alcohol in the presence of other higher or lower alcohols. Sulphated fatty alcohol (A) is a technical sodium lorol sulphate product containing approximately 60% of sodium lorol sulphate and 5% of sodium sulphate and sodium chloride, the remainder being water. Sulphated fatty alcohol (B) is a mixture of 1 part diethylcyclohexylamine lorol sulphatewith 2 parts of technical stearyl alcohol. Sulphated fatty alcohol (0) is a technical sodium lorol sulphate product containing about 45% of sodium lorol sulphate, the remainder being chiefly sodium sulphate.

As heretofore indicated, such emulsions may be applied to projectiles eitherloose or in finished cartridges by such methods as dipping, spraying or brushing. Due to the fine dispersion of the lubricating wax and the film forming properties of the emulsion, the evaporation of the fluid medium resultsin a substantially continuous lubrieating coating and a hard, dry and usually lustrous surface resembling a lacquer finish. This surface is resistant to ordinary abrasions, dry to touch, and foreignmaterials do not readily adhere to it. The quantity of lubricant on a pro- Jectile may be accurately regulated through control of either or both the concentration of the wax in the emulsion or the consistency of the emulsion.

The lubrication of projectiles by the use of emulsions is believed to be broadly new, and the appended claims are-accordingly to be given a broad construction. v

This application is a continuation-in-part of this inventors prior co-pending application, Serial No. 107,464, filed October 24, 1936.

What is claimed is:

1. A composition for the lubrication of pro- Jectiles which contains polyvinyl alcohol and parailin wax finely dispersed in a fiuid'medium.

2. A composition for the lubrication of projectiles consisting of an aqueous emulsion of paraflin wax and polyvinyl alcohol.

3. The method 'of lubricating projectiles which comprises applying thereto a composition containing paraflin wax andpolyvinyl alcohol dispersed in a fluid medium.

f1- The method of lubricating projectiles which comprises the steps of applying to the projectiles a water emulsion of paramn wax and polyvinyl alcohol and thereafter evaporating the water to leave upon the projectiles a thin substantially continuous and substantially dry-surfaced lubricatins film.

WALTER ARTHUR DEW.