US2124569A - Priming composition - Google Patents

Description

Patented July 26, 1938 UNITED STATES PATENT OFFICE PRIMING COMPOSITION George C. Hale and William H. Rinkenbach, Dover, N. J.

No Drawing. Original application September '26,

1935, Serial No. 42,284. Divided and this application January 24, 1938, Serial No. 186,708

2 Claims. (CI. 52 1) (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) The invention described herein may be manutruly homogeneous blend very diificult to obtain. factured and used by or for the Government for The lack of homogeneity which often results in governmental purposes, without the payment to the firing pin contacting only crystals or par-v us of any royalty thereon. ticles of the nonexplosive constituents of the 5 This invention relates to priming compositions priming mixture, is one of the main causes of 5 for propellent powders and other explosives, and ignition failures or ignition delays.

more particularly the use of normal lead dini- It has been considered that a marked improvetroresorcinate as the essential constituent of the ment in the uniformity of behavior of primer priming compositions. compositions would be obtained if compositions The term priming composition commonly recould be formulated so as to contain only explo- 10 fers and refers herein to an explosive composisive constituents. It was believed that if all nonti-on used to effect ignition of a propellent powder explosive oxidizing agents, fuels, and abrasives or other explosive. It is the function of a primor sensitizers could be eliminated and only sensiing composition to deliver intensely hot, flaming tive explosives used, the difficulty of attaining gases when combustion of the composition is inithe highest degree of homogeneity would be elimlo tiated by the impact or stab of a firing pin or inated; if all particles of the composition were other firing device. It is not required that the sensitive explosives any particle struck by the composition detonate or produce highly brisant firing pin would readily ignite. An extension 2 effects; in fact such effects are definitely avoided of this idea led to the belief that the ideal would compositions. Thus the sensitive, highly brisant alone, would provide all the characteristics reexplosives such as mercury fulrninate, lead azide, quired of a primer composition, i. e. the high delead styphnate, and hexanitromannite have never gree 0f s ty to impact, the pid rate of been used alone as priming compositions but it burning. the inability to detonate under the Conhas been general practice to employ such so called ditions of use, etc. We have discovered that 25 detonating agents in admixture with other manormal lead dinitroresorcinate has combined in terials which will reduce the brisant effect of the se f a t properties qu d for certain uses detonating agent and provide a sensitive priming of a pr Composition Which ust function mixture which will burn rather than detonate un er a s a or flame a It is i n y under the conditions of use. Apparently only sensitive to impact or flame that it ignites under one other type of priming composition has been the conditions available in ammunition, it burns used viz., a mixture of oxidizing agents, fuels p y W t out p ducing objeotional brisant or and sensitizing agents none of which alone are blast e ts Comparing s y Wit Standard milexplosive, or at least capable of detonating, but i ry pri r compositions n this p t. It is whi h h mixed become sensitive to ignition insoluble in water, does not absorb moisture from 35 and burn rapidly with intense heat effects. the air, and leaves no objectionable residue in the There is a fundamental objection to the two bore of the guns. Since it alone provides these types of priming mixtures referred to which have characteristics its use eliminates the hazard of been used up to the present time in that it is mixing, always present in the manufacture of extremely difiicult to provide the intimate mixing previous types of primer compositions. The

f ingredients necessary to Obtain the degree of chemical formula for normal lead dinitroresoruniformity desired. When it is considered that cinate is as follows; many primers are expected to fire from the stab of a sharp pointed firing pin which contacts only a very small part of the primer charge, which is present itself in only minute amount it is apparent that the maximum uniformity in composition is required if the primers are to function uni- Non formly. Yet as mentioned above the compositions in general use at present almost invariably It may be prepared by f of a lead Salt 50 contain three or four nonexpmsive constituents such as lead nitrate on sodium dlmtroresorcinate. such as ground glass, antimony sulphide, calce primers are used in y difierent types cium silicide, barium nitrate, etc., having widely of ammunition components such as military fuzes, different specific gravity, hardness, crystal form small arms cartridges, etc., it was recognized that and other physical characteristics which make a the lead dinitroresorcinate might not serve all of 55 by the common methods of formulating priming be attained if an explosive could be found which, 29'

these difierent purposes with the same degree of efficiency and an effort was made to modify its speed of action and sensitivity by employing it in mixture with other materials. It was found that such mixtures can be prepared which vary markedly in brisant efiects without losing the degree of sensitivity required for consistent functioning. Compositions comprising the lead dinitroresorcinate in admixture with finely divided black powder, in admixture with tetracene-and in admixture with nitrocellulose have been found to function efiiciently and with various speeds of action and with the production of an increased volume of gaseous products. A comparison of the behavior of the new compositionscontaining lead dinitroresorcinate, with a composition of the type in general use at present is shown in the following table:

Composition Egg $522 Impulse Gas volume Co. 1 Lead dmitroresorcinata. 100 2. 1.9 4. 4

2 Lead dinitroresorcinate 75 3. 5" 3. 3 6. 4

Black powder 25 3 Lead dinitroresorcinate. 75 3. 0" 2. 12" 4. 50

Tetracene 25 4 llxlezrcury fulgllinafie o assium c are e Antimony su1phide 21 0 8" 25 Ground glass 31 To facilitate loading, 2% of shellac in alcohol solution was added to moisten and bind the compositions.

Composition No. 4 is listed above as representative of the type in use at present and for comparison with the new compositions developed. It is noted that composition No. 1 comprising lead disitroresorcinate alone has even a higher degree of sensitivity than composition No. 4, substantially the same impulse value or brisant effect and a higher gas volume, while compositions 2 and 3 are intermediate in sensitivity between compositions 1 and 4 and have appreciably higher impulse and gas volume values than composition No. 4. It is thus indicated that the new compositions cited do not merely duplicate but are superior to the present type of composition No. 4 in both sensitivity and gas volume. In addition these new compositions are entirely free of ground glass, antimony sulphide or any other non-explosive material a particle of which may be contacted directly by a firing pin and thus lead to failure of the primer to ignite. An additional outstanding advantage of these compositions results from the resistance of lead dinitroresorcinate to decomposition. It has been found to have stability far superior to mercury fulminate and other sensitive explosives commonly used in primer compositions.

In general, any dinitro compound is much less sensitive than a trinitro compound and for this reason the latter type of compound is usually found in primer compositions. However, we discovered that lead dinitroresorcinate is even more sensitive than the trinitroresorcinol or the lead salt of trinitroresorcinol While having only approximately one-sixth the brisance. Accordingly it is more suitable in use for priming compositions where initiation is effected by the stab of a firing This application is a division of our co-pending application Serial Number 42,284, filed September 26, 1935, and now issued as Patent Number 2,116,514 dated May 10, 1938.

We claim:

1. A priming composition consisting of normal lead dinitroresorcinate 75% and tetracene 25%.

2. A priming composition consisting of normal lead dinitroresorcinate and tetracene.

GEORGE C. HALE. WILLIAM H. RINKENBACH.