WO1986005175A1

WO1986005175A1 - Process for the manufacture of combustible moulded ammunition components

Info

Publication number: WO1986005175A1
Application number: PCT/EP1986/000110
Authority: WO
Inventors: Manfred Haider; Ulrike Jeck; Jürgen KNOBLOCH; Wilhelm Oversohl (Deceased)
Original assignee: Wnc-Nitrochemie Gmbh; Oversohl, Elisabeth, Christine (Heiress Of Oversoh
Priority date: 1985-03-05
Filing date: 1986-03-04
Publication date: 1986-09-12
Also published as: EP0218614A1

Abstract

In a process for the manufacture of combustible moulded ammunition components of felted and hot-pressed fibre material, manufactured of cellulose, polyvinylchloride and, as the case may be, of nitrocellulose, the raw felts are pressed for densification and drying at temperatures at which polyvinylnitrate softens.

Description

Process for producing combustible ammunition parts.

Combustible molded ammunition parts are increasingly used as propellant charge containers or cartridge cases in tank cannons and field howitzers. Such molded parts consist of cellulose and one or more energy sources such as nitrocellulose, hexogen or octogen. Flammable molded parts made of cellulose and nitrocellulose have e.g. proven to be useful.

The ratio of the proportion of cellulose to the proportion of nitrocellulose depends on the demands placed on the molded parts in terms of strength and combustion behavior.

In addition to cellulose and nitrocellulose, the ammunition moldings contain a binding resin to achieve sufficient strength. The molded parts can be produced in a known manner of operation in such a way that suction molds are immersed in aqueous pulps of a suitable concentration or rotating suction molds are supplied with pulps to form raw felts which are compressed and dried in hot presses. Depending on the selected production method, raw felts can be produced in a uniform or zone-wise different composition. The binder resins can be introduced into the raw felts via the aqueous pulps or by immersing the pressed molded parts in a manner known per se.

It has proven to be generally necessary that approx. 15% binder resin has to be introduced into the molded parts in order to achieve a usable strength of the molded parts.

Since the binder resins significantly reduce the heat of explosion of the combustible material, the combustibility of the molded parts is impaired by the binder resin content. 10% resin content lower e.g. the heat of explosion of the combustible material around 150 - 220 cal / g.

In order not to reduce the flammability of the molded parts too much by the binder resin content, a compromise between the desired strength and the necessary flammability reserve must often be accepted.

Surprisingly, a way has now been found that solves this difficulty in a technically simple manner by introducing an energy source via the pulp into the raw felt, which acts as a binder resin. These two functions, on the one hand to be an energy carrier and on the other hand to be binding resin, can be fulfilled by polyvinyl nitrate (PVN).

The heat of explosion from PVN is 1180 cal / g

(= 4941 KJ / Kg); it is comparable to that of highly nitrated nitrocellulose.

Since PVN becomes plastic at 40 - 50 ° C, the conditions when hot pressing the raw felts can be selected so that that a binding resin effect is achieved by PVN. The press temperatures are advantageously kept between 100-120 ° C. The optimum pressing times are to be determined in tests depending on the raw felt thickness and the PVN content; they are usually between 5 and 8 minutes.

Flammable molded parts are obtained through PVN installation, the strength values of which are considerably higher than those with 12% binding resins.

The PVN can be introduced into the raw felt as fine-grained material or fiber via the aqueous pulps. α PVN can contain the nitrocellulose in the flammable

Replace molded parts completely so that the molded parts consist of cellulose and PVN.

In order to ensure optimum flammability of the molded parts in addition to high strength, it is often expedient to leave certain proportions of nitrocellulose in the molded parts. It should be noted here that increasing PVN content increases the material strength and increasing nitrocellulose content increases the flammability.

Advantageous compositions contain e.g. a share in

Pulp from 40% by weight PVN 30 to 50% by weight

Nitrocellulose 30 to 10% by weight

The following examples explain the method of operation according to the invention in its possibilities, but do not mean any limitation to the composition or method of implementation. Examples:

example 1

A raw felt of the following composition, calculated on dry substance, is produced in a known manner via an appropriately composed aqueous pulp.

unbleached pulp: 40%

Polyvinyl nitrate, ground: 40%

Nitrocellulose, 12.6% N ": 19% stabilizer, Centralit: 1%

After the raw felt was compacted for 4 minutes in a hot press at 130 ° C., a sleeve with the following material properties was obtained:

Wall thickness: 1.7 mm

₃ Density: 1.56 g / cm

Tensile strength: 420 bar

Explosive heat: 2190 Joule / g combustion behavior: 20 m / sec

Example 2:

A raw felt of the following composition, calculated on dry substance, is produced in a known manner via an appropriately composed aqueous pulp. bleached cellulose 40% polyvinyl nitrate, fibers 30%

Nitrocellulose, 13.25% N _, 29%

Stabilizer, acardite 1%

After compacting the raw felt for 4 minutes in a 1 13300 ° CC high-heat PPrreessssee wwuurrddee, obtain a sleeve with the following material properties

Wall thickness 1.8 mm, density 1.62 g / cm

Tensile strength 492 bar explosion heat 2161 Joule / g combustion behavior 12 m / sec

A raw felt with three zones of different composition is produced in a known manner via three correspondingly composed pulps. The three zones, when converted to dry matter, have the following compositions:

Zone 1 Zone 2 Zone 3 unbleached pulp 50% 60% 65% polyvinyl nitrate, fibers 25% 30% 34.5% nitrocellulose, 13.25% N t, 24.5% 9.5% -

Stabilizer, acardite 0.5% 0.5% 0.5%

After compacting the raw felt in a hot press at 130 ° C. for 4 minutes, a molded part with the following material properties was obtained: Zone 1 Zone 2 Zone

Wall thickness mm 1.52 1, 52 1, 53

Density g / cm3 1, 62 1, 58 1, 53

Tensile strength bar 566 579 603

Heat of explosion Joule / g 1800 1441 1243

Burning behavior m / sec 14 26 34.8

The zone-wise different composition was chosen for this molded part, a cartridge case with a firmly attached projectile, on the one hand to ensure the required mechanical strength on the projectile side in zone 3 and on the other hand to ensure sufficient combustion behavior on the weapon breech side in zone 1.

Claims

Expectations

1.

Process for the production of combustible ammunition parts from felted, and hot-pressed fiber material as

Fabric base, characterized in that the raw felts are made from cellulose and polyvinyl nitrate, optionally with the addition of nitrocellulose, and the raw felts are compressed for compression and drying at temperatures at which the polyvinyl nitrate softens.

Second

A method according to claim 1, characterized in that the nitrocellulose content up to 90% of the energy source:

Is polyvinyl nitrate + nitrocellulose.

3rd

A method according to claim 2, characterized in that the nitrocellulose content is 30-50% of the energy carrier: polyvinyl nitrate + nitrocellulose.

4. The method according to any one of claims 1-3, characterized ge indicates that the pressing of the water-moist raw felts takes place in presses hot above 100 ° C.

5th

Method according to claim 4, characterized in that the pressing of the water-moist raw felts in 110

- 130 C hot presses happens.

6th

Method according to one of claims 1 to 5, characterized in that the compacts to form ammunition such as cartridge cases, propellant charge containers, ignition tubes or the like. processed or assembled.