Procedures for the production of gun propellants by use of different extruders

Abstract

This report discusses the use of gun propellants produced by different types of extruders. These extruders are different to each other with respect to their construction, screw configuration and mode of operation. For the production of propellants by solvent processes, we preferred twin-screw extruders operating either in the synchronous mode or the countercurrent mode. The results of this process consist of extruded strands possessing a high density and an excellent surface, especially for single-base propellants produced by use of the countercurrent operating twin-screw extruder. The sychronous twin-screw extruder is mainly applied to the processing of triple-base propellants with a high content of nitroquanidine, such as e.g. M 30. The development of brittleness at low temperature is significantly improved as a result of the manufacturing technique employed. A planetary roller extruder, a four-screw extruder and a synchronously operating, twin-screw extruder are discussed with reference to the production of gun propellant without the use of solvent. A report is given on the advantages and properties of these extruders as regards optimal plastification of water-wet fibrous NC/NG mix. A method of producing propellant chips, which can be subjected to further processing by the selected extruder or a twin-roll unit, is also described. The ballistic properties of the resulting products are superior to those obtained by standard manufacturing processes.