CA2014123C - High temperature stable, low input energy primer/detonator - Google Patents

High temperature stable, low input energy primer/detonator Download PDF

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Publication number
CA2014123C
CA2014123C CA002014123A CA2014123A CA2014123C CA 2014123 C CA2014123 C CA 2014123C CA 002014123 A CA002014123 A CA 002014123A CA 2014123 A CA2014123 A CA 2014123A CA 2014123 C CA2014123 C CA 2014123C
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CA
Canada
Prior art keywords
weight
percent
sensitivity
reliability
sensitizer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CA002014123A
Other languages
French (fr)
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CA2014123A1 (en
Inventor
Ramaswamy Coodly
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Breed Automotive Technology Inc
Original Assignee
Breed Automotive Technology Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to GB9406466A priority Critical patent/GB2313373B/en
Priority claimed from GB9406457A external-priority patent/GB2313372B/en
Priority to GB9007635A priority patent/GB2313371B/en
Priority to GB9406457A priority patent/GB2313372B/en
Priority to GB9406467A priority patent/GB2313374B/en
Priority to CA002014123A priority patent/CA2014123C/en
Application filed by Breed Automotive Technology Inc filed Critical Breed Automotive Technology Inc
Priority to DE4012663A priority patent/DE4012663C2/en
Priority claimed from DE4012663A external-priority patent/DE4012663C2/en
Publication of CA2014123A1 publication Critical patent/CA2014123A1/en
Priority to GBGB9406458.1A priority patent/GB9406458D0/en
Publication of CA2014123C publication Critical patent/CA2014123C/en
Application granted granted Critical
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • CCHEMISTRY; METALLURGY
    • C06EXPLOSIVES; MATCHES
    • C06CDETONATING OR PRIMING DEVICES; FUSES; CHEMICAL LIGHTERS; PYROPHORIC COMPOSITIONS
    • C06C7/00Non-electric detonators; Blasting caps; Primers
    • CCHEMISTRY; METALLURGY
    • C06EXPLOSIVES; MATCHES
    • C06BEXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B21/00Apparatus or methods for working-up explosives, e.g. forming, cutting, drying
    • C06B21/0033Shaping the mixture
    • C06B21/0066Shaping the mixture by granulation, e.g. flaking
    • CCHEMISTRY; METALLURGY
    • C06EXPLOSIVES; MATCHES
    • C06CDETONATING OR PRIMING DEVICES; FUSES; CHEMICAL LIGHTERS; PYROPHORIC COMPOSITIONS
    • C06C9/00Chemical contact igniters; Chemical lighters

Abstract

A method for the manufacture of primers/detonators with 90-99.99% reliability and achieving sensitivity of 0.8 inch-oz to 3.0 inch-oz, able to withstand temperatures within the range of -40 C to 200 C and able to withstand temperature cycling and humidity for 95% RH at 95 C to -40 C. Mechanical and chemical sensitizers are utilized in lieu of tetracene, the utilization of oxidizers as sensitizers, the utilization of high energy fuels, and a method of co-precipitating the primary explosive and mechanical sensitizer.

Description

!,I 201q,~23 'i A HIGH TEMPERATURE STABLE, LOW INPUT ENERGY PRIMER/DETONATOR
~I Backuround of the Invention The invention relates to a method of manufacturing primers/detonators stable at high temperatures up to 1o0°C or better, having an all-fire impact sensitivity of 1.0 inch-oz or less, and high degree of reliability.
The invention more particularly relates to the development of a primer/detonator, which can function with a very high degree of reliability at temperatures as low as -40°C, as high as 100°C
or better, and function equally well at ambient temperatures, and ~ should have an all-fire sensitivity to impact of 1 inch-oz or less in the aforementioned temperature range.
i The explosive industry uses a variety of primers/detonators.
~i Basically these devices consist of a primary explosive component I
initiated by stab (friction) or impact, an intermediate explosive ;I composition to be set-off by the primer composition, and a base i~ charge of secondary explosive like RDX or HMX to give the desired output to perform work, which may be to set off another explosive I
device in the ignition train. One of the common low input energy primers/detonators is an M55 Detonator, which is extensively used in ordnance for anti-personnel and anti-vehicular munition systems. The make up of these detonators consist of:
i (a) A primary explosive composition containing basic lead i styphnate, dextrinated lead azide, antimony sulfide, barium ~,~ nitrate, and tetracene.
(b) An intermediate explosive charge of RD 1333 lead azide.
i; (c) RDX as secondary explosive.
! These detonators/primers are set-off by stab action with a ~~ firing pin and show a sensitivity of about 0.80 inch-oz at 99.99%
reliability and 95% confidence level. In this detonator system, while basic lead styphnate and dextrinated lead azide fill their ~~ role as the main primary explosives, barium nitrate fills the I
I
i ~0 14 1 23 I role as a supplier of oxygen to the system and the antimony II sulfide as a fuel cum mechanical sensitizes, because of its high melting point. But it is tetracene that plays a unique and important role. It is a chemical sensitizes with the unique property that makes the system function at an input sensitivity or energy below 1 inch-oz.
While tetracene is an excellent sensitizes and one of the best which explosive chemists have developed, its inherent weakness is that when temperatures higher than 85°C are encountered, the primers begin to fail. With heat aging above 85°C, the tetracene begins to decompose and leak out from the i primer. Sensitivity starts to decrease at 95°C, after 100 hours, i the impact energy required will be increased by at least a factor I~ of 3.
i While there are many applications for primers/detonators ',~~ that would function reliably at temperatures of 100°C or higher ~I (like high cycle firing machine guns), a civilian application is i !I in the automobile crash air bags used in motor vehicles for ~~ protecting occupants in crashes. In self-contained air bag j modules involving mechanical sensors, the primers are used to ignite the propellant system, which then generates the gas to inflate the air bag. The industry standards demand that air bag i~ systems function reliably at as high a temperature as 100°C; and at the same time function equally reliably at -40°C. Also, ;~ industry standards demand that they function with a high degree I~ of reliability and have a long shelf life.
The operating parameters expected for primers/detonators to !~ fulfill the aforesaid, as well as similar requirements can be I~
~i summed up as follows:
(i) The composition used in the primer should be easy v to manufacture and capable of loading in automatic industry 'I

machines used for manufacture of primers/detonators.
(ii) They should be safe for handling, particularly in systems using lead styphnate, where protection against static electricity may be an important safety factor.
(iii) They should be thoroughly stable at temperatures as high as 100°C and should function reliably at temperatures as low as -40°C.
(iv) In Systems using stab action energy to set off the system, the all-fire energy required for setting off the system should be 1 inch-oz or less, similar to those required for primers using tetracene as the sensitizer, where the all-fire sensitivity value is calculated statistically to 99.99% reliability and 95%
confidence level for the entire population.
umm~ry of the Invention A principal object of an aspect of the present invention is to provide conditions of assembly and, make up of detonators for the production of primers/detonators, with a high sensitivity to stab action and a high degree of reliability.
Another object of an aspect is to eliminate tetracene with its inherent limitation of decomposing at temperatures higher than 85°C~ and provide a method to use mechanical sensitizers like sand, glass powder, or carborundum in primer mixes to improve both sensitivity to impact and temperature aging.
~1 further object of an~aspect is to provide a method of the foregoing with a method to co-precipitate the mechanical sensitizer with an explosive to improve homogeneity and sensitivity.
Still another object of an aspect is to provide a composition using a powerful oxidizer like potassium chlorate as a sensitizer.
Still another object of an aspect is to provide a composition, eliminating primary explosives like azide and styphnate and using oxidizers and fuels like potassium chlorate, and antimony sulfide, in combination with a "., -3-mechanical and chemical sensitizer, to achieve a high degree of sensitivity, reliability, and temperature aging properties.
Another important object of an aspect is to improve the primers of the foregoing type to withstand very high temperature by using high energy fuels like selenium and titanium.
Still another important object of an aspect is to provide a method of manufacturing detonators with a high degree of reliability at 90%-99.99% reliability and 95%
confidence level, and achieve primers/detonators of sensitivity 0.8 inch-oz to 3.0 inch-oz, having temperature aging properties that would retain sensitivity from -40°C
to 200°C and capable of standing temperature cycling and humidity from 95% RH at 95°C to -40°C.
The above operating parameters could be achieved by eliminating tetracene with its inherent limitation of decomposing at temperatures higher than 85 C, and replacing it with mechanical sensitizers, or by developing an entirely different composition system, using ingredients which are highly stable at the temperatures for which the system is being designed.
According to an aspect of the invention, there is provided a consolidated mixture of a primer initiating composition omitting tetrazene as a sensitizer yet capable of withstanding aging and providing a relatively high degree of sensitivity, reliability, and confidence level within a wide temperature range consisting essentially of:
from 40 to 42 weight percent of basic lead styphnate;
from 20 to 22 weight percent of lead azide;
from 15 to 20 weight of barium nitrate; and from 1 to 3 weight percent of a sensitizer selected from the group consisting of silicon carbide, fused alumina, ground glass powder, and pure silica sand.
According to an aspect of the invention, A method of forming an explosive primer capable of withstanding aging within the temperature ranging from -40 C to 200 C and providing sensitivity of 0.80 inch-oz at 99.99% reliability and 95% confidence level, which comprises forming a mixture consisting of:

(a)from 40 to 42 percent by weight of basic lead styphnate;
(b) from 20 to 22 percent by weight of lead azide;
(c) from 15 to 20 percent by weight of antimony sulfide;
(d) from 15 to 25 percent by weight of an oxidizer selected from the group consisting of Chlorate and barium nitrate; and (e) from 1 to 3 percent by weight of a mechanical sensitizer selected from the group consisting of glass powder, and sand; and taking from 15 to 25 mg of the mixture formed; and consolidating the taken mixture under a pressure of from 70 to 100 kpsi.
Other objectives and advantages of the invention will become more apparent to those skilled in the art, as the invention is -4a-disclosed in the examples given below:
Detailed Description Primer Initiating Composition Basis Lead Styphnate - 40 - 42% )use 15-25 Lead Azide - 20 - 22% )milligrams and Antimony Sulfide - 15 - 20% )consolidate at Barium Nitrate - 15 - 20% ) 70-100 Kpsi Carborundum - 1 - 3% ) y Intermediate charges and the base charge could be varied i ~) from the standard intermediate lead azide and base charges like j PETN, RDX, or HMX to less powerful output charges, like a mixture ~~ of basic lead styphnate, barium nitrate and antimony sulfide or i titanium-potassium perchlorate or zirconium-potassium perchlorate.
Detonators assembled as above and initiated by a standard firing pin would stand aging at 100°C and would give a sensitivity of 2-3 inch-oz at 99% reliability and 95% confidence level.
EXAMPLE II
Similar to Example I, but replacing carborundum with ground glass powder or pure silica sand-like Ottawa sand and in the same sieve size spectrum as for carborundum in Example I and with output charge as desired. Weight of charge and consolidation pressures also as in Example I, would give primers with a sensitivity of 2-3 inch-oz at 90% reliability and 95% confidence level.

2~ ~4 ~ 2~
! ! ~,xAMPLE m The reliability of mixing mechanical sensitizers like carborundum, sand and glass powder could be very much improved i ~ and thus improve the overall reliability by encapsulating the sensitizer into the primary explosive by co-precipitating the ~ primary explosive and the mechanical sensitizer. As an example, the lead styphnate and mechanical sensitizer like carborundum, sand, or glass powder could be co-precipitated in the proportion i they would be present in the final composition. The method of Preparation would be as follows:
A solution of magnesium styphnate is prepared by i il neutralizing styphnic acid with magnesium oxide, filtering off I
j the excess magnesium oxide. The mechanical sensitzer ~~ is suspended in the magnesium styphnate solution in the .proportion it exists in the final mixture. Lead nitrate or lead il i acetate solution is run down into the mixture of magnesium styphnate and mechanical sensitizer, which is kept stirred at 50 C. The co-precipitated lead styphnate mechanical sensitizer is cooked at 50 C for a further period of 10 minutes, filtered washed thrice with distilled water, and used in making the primer composition.
Primer/detonator made up with the above co-precipitated mix and in a manner similar to that in Example I, improves uniformity, and gives a primer with a sensitivity of 3-3.5 inch-oz at 99.99%
i reliability and a 95% confidence level.

2~~4~23 EXAMPLE IV
~i p The mix in Example I could be sensitized by using a more powerful oxidizer in place of tetracene. A typical mix made with the following composition:
Lead Styphnate - 40%
Lead Azide - 20%
Antimony Sulfide - 15%
I Barium Nitrate - 20%
Potassium Chlorate - 5%
i) j The composition in Example IV can be used in place of the primary mix in Example I and primers/detonators made as in Example I, ~~ using 25 mgms of the primer composition, consolidated at 100 i K.psi gives detonators/primers with a sensitivity of 3.1 inch-oz i ~~ at 99.99% reliability and 95% confidence level.
II
EXAMPLE V
A completely new approach is by, going away from the conventional primary explosives and still achieve a high degree of sensitivity. This is achieved by using a combination of mechanical and chemical sensitizers. A typical example of such a type is:
Potassium Chlorate - 35 - 37%
Antimony Sulfide - 52 - 56%
i Glass Powder - 2 - 3%
Sulfur - 3 - 4%
i Lead Thiocyanate - 4 - 6%
The detonator/primer made using the above primary mix, using 15-25 mgms of the mix pressed at 70-100 Kpsi, has an all-fire I stab sensitivity of 0.80 inch-oz at 99.99% reliability and 95%
confidence level. The base charge could be varied to suit the , output desired. Its functionally reliable after aging both at -'I
il 't 40 C and 100 C for extended periods, without any significant loss in sensitivity.
t EXAMPLE VI
The sulfur in Example V can be substituted with high energetic fuels like selenium, titanium, or zirconium. They would maintain the sensitivity and at the same time allow them to be used up to 200 C without loss in sensitivity.
The scope and ambit of the invention is not limited to the i j materials, conditions of processing, and assembly of the primer/detonator mentioned. As an example, co-precipitating the il lead azide and lead styphate in the proportion it exists in the i composition would achieve a higher degree of sensitivity or replace part of the oxidizer in Examples I to III with a more powerful oxidizer like potassium chlorate. Judicious combination I
of the ingredients could lead to higher sensitivity and higher output. Similarly, newer designs of the firing pin with more acute included angle from 26 used in standard pin up to 14 and I
also more edges on the pins to develop more hot spots for initiation would make the system function at lesser impact energy.
Thus, the several aforementioned objects and advantages are most effectively attained by the invention which has important I application in the ordinance, automobile crash air bag and other i fields having need for primers/detonators. Although several 'i embodiments have been disclosed in detail herein, it should be understood that this invention is in no sense limited thereby and its scope is to have determined by that of the appended claims.
~ li li .1 i :; ;~, ;-i:;:: . .. : , ,

Claims (2)

1. A consolidated mixture of a primer initiating composition omitting tetrazene as a sensitizer yet capable of withstanding aging and providing a relatively high degree of sensitivity, reliability, and confidence level within a wide temperature range consisting essentially of:
from 40 to 42 weight percent of basic lead styphnate;
from 20 to 22 weight percent of lead azide;
from 15 to 20 weight of barium nitrate; and from 1 to 3 weight percent of a sensitizer selected from the group consisting of silicon carbide, fused alumina, ground glass powder, and pure silica sand.
2. A method of forming an explosive primer capable of withstanding aging within the temperature ranging from -40 C to 200 C and providing sensitivity of 0.80 inch-oz at 99.99 reliability and 95% confidence level, which comprises forming a mixture consisting of:
(a)from 40 to 42 percent by weight of basic lead styphnate;
(b) from 20 to 22 percent by weight of lead azide;
(c) from 15 to 20 percent by weight of antimony sulfide;
(d) from 15 to 25 percent by weight of an oxidizer selected from the group consisting of Chlorate and barium nitrate; and (e) from 1 to 3 percent by weight of a mechanical sensitizer selected from the group consisting of glass powder, and sand; and taking from 15 to 25 mg of the mixture formed; and consolidating the taken mixture under a pressure of from 70 to 100 kpsi.
CA002014123A 1990-04-04 1990-04-09 High temperature stable, low input energy primer/detonator Expired - Fee Related CA2014123C (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
GB9007635A GB2313371B (en) 1990-04-04 1990-04-04 A high temperature stable,low input energy primer/detonator
GB9406457A GB2313372B (en) 1990-04-04 1990-04-04 A high temperature stable,low input energy primer/detonator
GB9406467A GB2313374B (en) 1990-04-04 1990-04-04 A high temperature stable,low input energy primer/detonator
GB9406466A GB2313373B (en) 1990-04-04 1990-04-04 A high temperature stable,low input energy primer/detonator
CA002014123A CA2014123C (en) 1990-04-04 1990-04-09 High temperature stable, low input energy primer/detonator
DE4012663A DE4012663C2 (en) 1990-04-04 1990-04-20 Ignition initiation composition
GBGB9406458.1A GB9406458D0 (en) 1990-04-04 1994-03-31 A high temperature stable,low input energy primer/detonator

Applications Claiming Priority (7)

Application Number Priority Date Filing Date Title
GB9007635A GB2313371B (en) 1990-04-04 1990-04-04 A high temperature stable,low input energy primer/detonator
GB9406457A GB2313372B (en) 1990-04-04 1990-04-04 A high temperature stable,low input energy primer/detonator
GB9406467A GB2313374B (en) 1990-04-04 1990-04-04 A high temperature stable,low input energy primer/detonator
GB9406466A GB2313373B (en) 1990-04-04 1990-04-04 A high temperature stable,low input energy primer/detonator
CA002014123A CA2014123C (en) 1990-04-04 1990-04-09 High temperature stable, low input energy primer/detonator
DE4012663A DE4012663C2 (en) 1990-04-04 1990-04-20 Ignition initiation composition
GBGB9406458.1A GB9406458D0 (en) 1990-04-04 1994-03-31 A high temperature stable,low input energy primer/detonator

Publications (2)

Publication Number Publication Date
CA2014123A1 CA2014123A1 (en) 1991-10-10
CA2014123C true CA2014123C (en) 2001-11-20

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Application Number Title Priority Date Filing Date
CA002014123A Expired - Fee Related CA2014123C (en) 1990-04-04 1990-04-09 High temperature stable, low input energy primer/detonator

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Country Link
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GB (2) GB2313371B (en)

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3321343A (en) * 1966-03-28 1967-05-23 Olin Mathieson Priming composition containing carbon which exhibits conchoidal fracture
GB1204417A (en) * 1967-05-18 1970-09-09 Olin Corp Formerly Known As Ol Ammunition priming compositions and processes of making them
US4029530A (en) * 1974-07-18 1977-06-14 Remington Arms Company, Inc. Method of forming lead styphnate ammunition priming mixture
CH594578A5 (en) * 1977-04-07 1978-01-13 Oerlikon Buehrle Ag
GB2045225B (en) * 1979-03-07 1982-11-10 Ici Ltd Explosive composition
NO142837C (en) * 1979-06-01 1982-09-16 Dyno Industrier As POWDER-SHEET, FUEL-SENSITIVE EXPLOSION WITHOUT EXPLOSIVE COMPONENTS
DE2952069C2 (en) * 1979-12-22 1983-02-17 Dynamit Nobel Ag, 5210 Troisdorf Use of zinc peroxide in explosive or pyrotechnic mixtures
DE3008001C2 (en) * 1980-03-01 1982-06-03 Dynamit Nobel Ag, 5210 Troisdorf Pyrotechnic mixture of sentences for delay elements
DE3321943A1 (en) * 1983-06-18 1984-12-20 Dynamit Nobel Ag, 5210 Troisdorf LEAD- AND BARIUM-FREE APPLICATION SETS
US4608102A (en) * 1984-11-14 1986-08-26 Omark Industries, Inc. Primer composition
US5015311A (en) * 1990-10-05 1991-05-14 Breed Automotive Technology, Inc. Primary/detonator compositions suitable for use in copper cups

Also Published As

Publication number Publication date
GB9406458D0 (en) 1997-09-17
GB2313371A (en) 1997-11-26
CA2014123A1 (en) 1991-10-10
GB9007635D0 (en) 1997-09-03
GB2313371B (en) 1998-02-18

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