DE2407962C3 - Detonating fuse - Google Patents

Description

The preferred copolymer is a copolymer of ethylene and vinyl acetate. The copolymers should preferably have a melt flow index from 0.1 to 25, preferably from 1 to 7 the measurement according to British standard 2782, part 1/105 c / 1970 at a load of 2 16 kg takes place.

Since the melting point of the copolymer is lower than that of the polyethylene, the copolymer is expediently by extrusion, preferably duich pressure extrusion, on the Fuse applied, whereby high quality

else 1 to 7, has.

4. Detonating fuse according to one of the antigen, extruded sheaths with much smaller ones Proverbs 1 to 3, characterized in that the extrusion temperatures are obtained as they are bis-copolymer is applied to the fuse through her for extrusion of outer sheaths on pressure extrusion. Detonating fuses were necessary. To this

5. Detonating fuse according to one of the methods used in the manufacture of fuses Proverbs 1 to 4, characterized in that the 30 with a PETN core is the extrusion temperature Jacket made of mixed polymer of finely divided carbon - kept below the PETN melting point werstoff contains. the.

The fuse advantageously has an or

several reinforcement layers made of textile winding,

as with conventional fuses around the

The invention relates to a detonating fuse with a Sprengsioffkern are wound. Textile-wrapped core, in particular made of pentaerythritol-tetra fuses, previously had a low level of water-resistant nitrate, which may develop around the explosive core, mainly because of the tendency of the water, to form reinforcing layers made of textile through capillary action along the textile layer like fine-fiber thermoplastic yarn wandering and holding by one immersed in water and penetrating an outer extruded watertight cord end from the side over long distances in a sheath made of a thermoplastic material on the explosive core,
shows. It has now surprisingly been found that

A detonating fuse usually contains a copolymer used according to the invention Core made of explosive material, which is released by a 45 during the extrusion into the interstices of the Reinforcement wrap is surrounded, for example, the textile layer penetrates and the migration of the Wasvon natural or synthetic textile yarns. This is largely prevented by the textile layer the detonating fuse usually has a core. The water resistance of the detonating cord will made of PETN (pentaerythrite tetranitrate), and a safety-improved as a result. Fuses with particularly good The fuse has a black powder core. The 50 water resistance can be established, though The core is often a thin cover made of paper or the textile windings made of fine-fiber plastic-plastic film The reinforcing yarns are yarn, e.g. B. fine-fiber polypropylene, exist, which is placed around the cover, and a waterproof man-made fine-fiber polypropylene thread that is tied with a hot rod Plastics are usually made from extruded hot melt adhesive from a copolymer made from ethypresses applied to the yarns. The waterproof 55 len and vinyl acetate coated is in this outward coat usually consists of plasticized looks particularly suitable. Examples of such hot polyvinyl chloride (PVC) or polyethylene, and the hot-melt adhesives are mentioned in DT-OS 22 03 261, required extrusion temperature exceeds 160 ° C, in applications where there is a risk that the

a temperature that experiences an electrostatic charge above the melting point of the fuse, PETN (141 ° C). There is, therefore, a great deal of risk that the interpolymer shell may be made conductive during the extrusion process of fine carbon, which is excessively heated and ignited. The advantage is that any charge can easily report such accidents. It would therefore be able to be derived to earth
Of course, it is advantageous to use a jacket material. In addition to the advantages mentioned above, the

use that can be extruded at lower temperature 65 fuse according to the invention at low temperatures. doors more flexible and surprisingly more abrasion-resistant

The object of the invention is therefore to provide a fuse as fuse with polyvinyl chloride or polyamide an outer, watertight, extruded ethylene jacket. She is therefore taking for use

more suitable for harsh conditions, for example in frozen areas and for hanging Explosive charges in raw firing holes.

The invention is further illustrated by the following examples of detonating fuse, 5 of which Examples 1 and 2 have conventional PVC or polyethylene jackets and are used for comparison, while Examples 3 to 5 correspond to the invention.

The detonating fuses are carried out by a common The fuse-making method used, for example, in GB-PS 20 200 is described. The cords have a charge rate crystalline PETN explosive core of 10 g / ro, that of a 0.18 mm thick. a 15 Paper tube is surrounded. The paper tube was covered with a helically spun reinforcement layer from 10 strands of one fibrillated by pin rolling 1000 denier polypropylene tape, 2.5 mm wide and 0.01 mm thick, with 26 turns / m was spun, covered what a helically spun sheet of 8 strands of the same fibrillated by pin rolls Polypropylene tape with 39 turns / m followed. A 0.4 mm thick plastic jacket was through a Cross-head extrusion machine extruded around the polypropylene layers, the shell of the Examples 3 to 5 were extruded under pressure.

In Example 1, the jacket consisted of PVC, which was mixed with 36 parts of diisooctyl phthalate to 100 parts of PVC was softened.

In Example 2, the jacket was made of a low density polyethylene. In Examples 3 to 5 it consisted of a copolymer of ethylene and vinyl acetate with a melt flow index of Copolymer of 2. The properties of the fuses of the Examples are as follows Table given.

Extrusion head temperature

/ \ friction resistance

(mean number of movements for

the hole formation)

Low temperature behavior
Cold bending temperature
Cold forming temperature
Charpy embrittlement temperature

Water resistance
(medium penetration after
24 hours)

Gap propagation

Detonation velocity

tensile strenght

Example _c

3 4 5

Jacket material x, i,., I »"

^ - sä * - S ^ ^ s. S ^

¹ ^ ^VL - 28 »/ oVA 18» / oVA 7 "/ oVA

170 ⁰ C 165 ⁰ C 11O ⁰ C 13O ⁰ C 135 ° C 2.5 12.8 7.5 16.4 18.0 -22 ⁰ C
.-45 ⁰ C -10 to
-2O ⁰ C -4O ⁰ C
-7O ⁰ C
-30 to
-35 ⁰ C -39 ⁰ C
-70 ⁰ C
-30 to
-35 ⁰ C -39 ⁰ C
-7O ⁰ C
-30 to
-35 ⁰ C

110 cm cm

16 cm

17 cm

17 cm

16 mm t 100 kg 16 mm kg 16 mm I. 100 kg 16 mm kg 16 mm kg 6.8 6.8 6.8 6.8 6.8 > > 100 > > 100 > 100

The abrasion resistance was determined by: man a length of detonating cord weighing 3 kg at one end over the right-angled edge of a concrete block while the other end was held at an angle of 30 ° to the horizontal would. The cord was repeatedly moved over the concrete edge until the jacket became holey. The mean number of movements required is given for each example.

The low temperature behavior was determined as the temperature at which the jacket becomes brittle or brittle became too stiff to knot two ends of the cord together. The cold bending temperature was determined according to Standard 2782. Part 1/104 B / 1970, the KaIt-55 deformation temperature according to the British standard 2782, part 1/104 B / 1970 and the Charpy embrittlement temperature according to British standard 2782/306 E / 1970 determined.

The water resistance was determined in the following manner

60 determined: Vertically suspended lengths of detonating cord dived with one end exposed for 24 hours 1.6 m under water. The distance that the water penetrated along the line was measured was.

65 The test for crevice propagation was as follows: Two lengths of detonating cord were parallel to each other held at a measured distance with an air gap in between. It became the maximum

definitely stood at which the detonation was carried over from one length of the cord to the other.

The test results in the table show that the fuse of Examples 3 to 5 at a temperature encased under the PETN melting point would. These fuses were re

the with

flexibility and flexibility ί encased ignition _exp i _os i _V en and mecha-

equally little.

Claims (3)

Patent claims: 1. Detonating fuse with a core, in particular made of pentaerythritol tetranitrai, which if necessary reinforcement layers wrapped around the explosive core from textile windings, such as fine-fiber thermoplastic yarn and an outer extruded waterproof jacket made of a thermoplastic material, characterized in that the jacket material consists of a copolymer consists of ethylene and 7 to 30 percent by weight vinyl acetate, alkyl acrylate or alkyl methacrylate, wherein the alkyl group contains 1 to 4 carbon atoms. 2. detonating fuse according to claim 1, characterized in that the jacket material is a copolymer of ethylene and ethyl acrylate, butyl acrylate or methyl methacrylate. ao 3. detonating fuse according to claim 1 or 2, characterized in that the copolymer a melt flow index of 0.1 to 25, preferably 1 to 7, has. To provide jacket, the material of which can be extruded at lower temperatures and supplies fuses with all other desirable properties, ...,. .. "_, The solution to this problem is according to the invention that the jacket material consists of a Copolymer of ethylene and 7 to 30 percent by weight vinyl acetate, alkyl acrylate or alkyl methacrylate consists, the alkyl group containing 1 to 4 carbon atoms. Suitable acrylates and methacrylates are ethyl and butyl acrylate as well as methyl meth-