WO1994002434A1

WO1994002434A1 - Explosive body

Info

Publication number: WO1994002434A1
Application number: PCT/SE1993/000640
Authority: WO
Inventors: Abraham Langlet; Henric ÖSTMARK
Original assignee: Försvarets Forskningsanstalt
Priority date: 1992-07-24
Filing date: 1993-07-22
Publication date: 1994-02-03
Also published as: SE9202232L; SE9202232D0; AU4595493A; SE500178C2

Abstract

An explosive body based on an explosive substance of the triazole or triazolone type contains within a restricted area a salt of the explosive substance having higher sensitivity to initiation than the rest of the explosive body. The invention also relates to a method of preparing the explosive body, in which the body is first moulded and compacted from the explosive substance of the triazole or triazolone type, whereupon a restricted area of the body is treated with an aqueous solution which diffuses into the body and forms with the explosive substance a salt having higher sensitivity to initiation than the rest of the explosive body.

Description

EXPLOS IVE BODY

The present invention relates to an explosive body based on an explosive substance of the triazole or triazolone type, and to a method of prepar¬ ing such an explosive body. More specifically, the invention relates to an explosive body of nitro- and/or aminotriazole or nitro- and/or amino- triazolone, which has been modified in respect of its sensitivity to initiation to be more useful as detonation transmitter in explosive trains, for instance as a so-called primary or booster charge, or in detonators.

A booster charge intensifies an initiation source to bring a less sensi¬ tive explosive to safe and complete detonation. It should have a suffi¬ ciently low initiation energy to be caused, with great reliability, to detonate when affected by the initiation source, and be sufficiently powerful to ensure complete detonation of the less sensitive explosive, such as a main charge or the next step in the explosive train. At the same time, it is desirable, in terms of safety, that the booster charge is as insensitive as possible.

Explosive substances of the triazole and triazolone type are relatively insensitive. This group includes, for instance, NTO (3-nitro-l,2,4- triazol-5-one) as described e.g. in US Patent Specification 4,733,610; ANTA (5-amino-3-nitro-lH-l,2,4-triazole) and DNT (3,5-dinitro-lH-l,2,4- triazole), as described e.g. in Journal of Energetic Materials Vol. 9, 415-428 (1991), K.Y. Lee, C.B. Storm, M.A. Hiskey and M.D. Coburn: An improved synthesis of 5-amino-3-nitro-lH-l,2,4-triazole (ANTA), a useful intermediate for the preparation of insensitive high explosives.

The major advantage of explosive substances of this type is their insen- sitivity to initiation, which however also means that they are not normally suited for use as primary/booster charge or in detonators. The present invention is based on the insight that their sensitivity to initiation can be increased by preparing salts of the explosive substan¬ ce that are more sensitive to initiation than the pure explosive subs¬ tance.

One object of the invention is to provide an explosive body of an explo¬ sive substance of the triazole or triazolone type which accommodates the requirements of insensitivity and initiability and is suited for use e.g. in detonators or as a Dooster charge. Another object of the invention is to provide an explosive body whose sensitivity to initiation can be adapted to the initiation source used.

Yet another object of the invention is to provide an explosive body having increased sensitivity to initiation only in a restricted area thereof.

These objects are achieved by means of an explosive body and a method for preparing the explosive body as defined in the appended claims.

According to the invention, there is provided an explosive body of an explosive substance of the triazole or triazolone type, said body con¬ taining within a restricted area a salt of the explosive substance which is more sensitive to initiation than the rest of the explosive body. The explosive body may advantageously be used as a booster charge and the like, in which the area having higher sensitivity to initiation consists of a restricted superficial part which is turned towards the initiator element.

The salt may consist of a metal salt of the explosive substance with one or more of the metals barium, lead, mercury, chromium, silver, iron, copper, sodium, tallium, tin, uranium, zinc, cobalt, cadmium, molyb¬ denum, strontium, bismuth, tungsten, zirconium and cesium. The salt may also be an organic salt of the explosive substance, such as an amine salt, hydrazine salt, diaminoguanidine salt or triaminoguanidine salt.

Suitable explosive substances of the triazole or triazolone type may consist of nitrotriazolone of the general formula

wherein R, and R_? are the same or different and selected from the group consisting of hydrogen, halogen and -Nh , or a triazole of the general formula

N — N -

wherein R₃ and R. are the same or different and selected from the group consisting of -NO and -NH .

Especially suitable explosive substances for use in the invention are

NTO, 3-nitro-l,2,4-triazol-5-one

3-nitro-4-fluoro-l,2,4-triazol-5-one

l-fluoro-3-nitro-l,2,4-triazol-5-one

l-amino-3-nitro-l,2,4-triazol-5-one

\

3-nitro-l,2,4-triazole NO,

N — N

ANTA, 5-amino-3-nitro-lH-l,2,4-triazole H₂N- NO, N

H \ N — N

3.5-diamino-lH-l,2,4-triazole _H / \ NH, 3 , 5-di ni tro-lH-l , 2 , 4-tri azol e

The invention also relates to a method of preparing an explosive body of the type described above, wherein a restricted area of an explosive body of the triazole or triazolone type is treated with a solution which diffuses into the body and forms with the explosive substance a salt having higher sensitivity to initiation than the rest of the explosive body.

In the method of preparation, the explosive body is first moulded and compacted from the relatively insensitive explosive base substance. An aqueous solution containing ions of one of the above-mentioned metals or a ine/hydrazine/guanidine is thereafter dripped onto the body. The solution diffuses somewhat into the body, and a salt of the explosive substance is obtained within a restricted area which is penetrated by the solution. Explosive substances of the triazole and triazolone type are acid and release in the presence of water a proton which can be taken up by the negative ion of the added solution. The metals are added in the form of salts where the negative ion in this reaction forms a weaker acid than the explosive substance and can be driven off from the explosive body by drying. It is especially preferred to use acetates of the metals. After drying, an explosive body has been achieved whose main part consists of an insensitive explosive substance of the triazole or triazolone type which has been changed locally to a more initiation- sensitive salt of the explosive substance. When a restricted, super¬ ficial part of the explosive body is treated in this way, the body becomes sensitive to initiation from one direction only. In the finished charge, the treated portion is thus turned towards the initiator element and a charge is obtained that is relatively insensitive to influence other than from the initiator element used.

The invention also makes it possible to adapt the initiation sensitivity to different initiation sources, such as laser initiators by the choice of solution to be dripped onto the explosive body, the concentration of the solution and the amount thereof.

The invention will be illustrated bv the followinα Examples. Exampl e 1 .

An aqueous solution of lead acetate was dripped onto NTO. After drying, the thus-treated explosive substance was tested by a fallhammer test and for friction sensitivity, and was compared with untreated NTO.

In the fallhammer test, use was made of a falling weight of 2 kg and a 50% ignition frequence was obtained at a fall height of 22.5 cm. For pure NTO, no ignition was obtained even at a fall height of 84 cm.

In friction tests, ignition occasionally occurred at a contact load of 16 kp. For pure NTO, no ignition was obtained even at a contact load of 36 kp.

Example 2.

A body was moulded and pressed from NTO. On a restricted area of the body, an aqueous solution of lead acetate was dripped and allowed to diffuse into the explosive substance. The body was thereafter allowed to dry in room temperature and acetic acid was evaporated. An initiator element in the form of an electric ignitor was placed against the treat¬ ed surface and, upon initiation, the body detonated completely.

Claims

Claims:

1. An explosive body based on an explosive substance of the triazole or triazolone type, c h a r a c t e r i z e d in that it contains within a restricted area a salt of the explosive substance having higher sen¬ sitivity to initiation than the rest of the explosive body.

2. An explosive body as claimed in claim 1, c h a r a c t e r i z e d in that the restricted area consists of a superficial part adapted to be turned towards an initiator element.

3. An explosive body as claimed in claim 1, c h a r a c t e r i z e d in that the explosive substance is 3-nitro-l,2,4-triazol-5-one (NTO).

4. An explosive body as claimed in claim 1, c h a r a c t e r i z e d in that the explosive substance is 3-nitro-4-fluoro-l,2,4-triazol-5-one.

5. An explosive body as claimed in claim 1, c h a r a c t e r i z e d in that the explosive substance is l-fluoro-3-nitro-l,2,4-triazol-5-one.

6. An explosive body as claimed in claim 1, c h a r a c t e r i z e d in that the explosive substance is l-amino-3-nitro-l,2,4-triazol-5-one.

7. An explosive body as claimed in claim 1, c h a r a c t e r i z e d in that the explosive substance is 3-nitro-l,2,4-triazole.

8. An explosive body as claimed in claim 1, c h a r a c t e r i z e d in that the explosive substance is 5-amino-3-nitro-lH-l,2,4-triazole (ANTA) .

9. An explosive body as claimed in claim 1, c h a r a c t e r i z e d in that the explosive substance is 3,5-diamino-lH-l,2,4-triazole.

10. An explosive body as claimed in claim 1, c h a r a c t e r i z e d in that the explosive substance is 3,5-dinitro-lH-l,2,4-triazole.

11. An explosive body as claimed in claim 1, c h a r a c t e r i z e d in that the salt of the explosive substance is a metal salt of one or more metals selected from the grouD consisting of barium, lead, mercury, chromium, silver, iron, copper, sodium, tallium, tin, uranium, zinc, cobalt, cadmium, molybdenum, strontium, bismuth, tungsten, zirconium and cesium.

12. An explosive body as claimed in claim 1, c h a r a c t e r i z e d in that the salt of the explosive substance is an organic salt selected from the group consisting of amine salt, hydrazine salt, diaminoguani- dine salt and tria inoguanidine salt.

13. A method of preparing an explosive body as claimed in claim 1, c h a r a c t e r i z e d by moulding an explosive body based on an explosive substance of the triazole or triazolone type, and treating a restricted area of the body with a solution which diffuses into the body and forms with the explosive substance a salt having higher sensitivity to initiation than the rest of the explosive body.

14. A method as claimed in claim 13, c h a r a c t e r i z e d in that the explosive substance of the triazole or triazolone type is selected from the group consisting of 3-nitro-l,2,4-triazol-5-one; 3-nitro-4- f 1 uoro-1 , 2 , 4-tri azol -5-one ; 1-f 1 uoro-3-ni tro-1 , 2 , 4-tri azol -5-one ; 1- amino-3-nitro-l,2,4-triazol-5-one; 3-ni tro-1, 2, 4-tri azol e; 5-amino-3- nitro-lH-1, 2, 4-tri azol e; 3,5-diamino-lH-l,2,4-triazole; 3,5-dinitro-lH- 1,2, 4-tri azol e.

15. A method as claimed in claim 13, c h a r a c t e r i z e d in that the solution is an aqueous solution of one or more metal salts.

16. A method as claimed in claim 13, c h a r a c t e r i z e d in that the solution is an aqueous solution of an amine, hydrazine, diamino- guanidine or triaminoguanidine.