Twin screw compounders

Fig. 11.25 Schematic of twin-screw compounding system for producing glass-reinforced polymer pellets. [Reprinted by permission from D. B. Todd and D. K. Baumann, Twin Srew Reinforced Plastics Compounding, Polym. Eng. Set, 18, 321-325 (1978).]...

As described in the preface, the first co-rotating twin screw extruders in the ZSK series were put into operation in 1957. According to Herrmann [1], ZSK is the abbreviation for the German expression Two-shaft kneading disc extruder (Zweiwellige Knetscheiben-Schneckenpresse). The expression twin-screw compounder used in the preface is the term... 

Figure 16.5 shows examples of screw barrel designs for the ZSK twin-screw compounder. 

Table 16.2 Examples of material choices for barrels with wear inserts as well as for solid barrels in ZSK twin-screw compounders... 

The first twin-screw compounder (ZSK) went into production at Werner Pfleiderer in 1957, marking the beginning of a success story for this type of machine. The first major applications were in the chemical industry. Today, the machine is predominantly used in the plastics industry, e. g., in extrusion and compounding. These screw machines are therefore also known as extruders and the twin-screw is known as the twin-screw extruder. 

Fig. 5 Schematic diagram of a twin-screw compounding extruder. (From Ref. f)...

Miyagawa, Y. Sato, H. Okabe, T. Nishiyama, T. Miyajima, M. Sunada, H. In vivo performance of wax matrix granules prepared by a twin-screw compounding extruder. Drug Dev. Ind. Pharm. 1999, 25, 429-435. 

Anonymous, High Performance Twin-screw Compounding System, Werner Pfleiderer GmbH, Techn. Inf. BuU. Nos. 21E.8910A.1000, 05-098/2, 05-085/1, 05-100/2 (1989). 

The recent acquisition of Colortech by PPM, a German color compounder, presented an opportunity to eonduet a direct comparison of thermo-kinetic and conventional twin screw compounding technologies. The goal was to run identical color concentrate formulations on commercial scale processing equipment operated by individuals skilled in the art. Primary performance criteria were to include dispersion quality and color strength. Secondary characteristics such as melt index, ash content and product density were also evaluated. 

Five commercial LLDPE and LLDPE/LDPE-based concentrate formulations were selected for comparison in HIDM and Twin Screw compounding trials (see Table 1). 

Twin screw compounding work was carried out in Bingen, Germany on a Theysohn TSK 60 mm 36 1 L/D co-rotating twin screw extruder fitted with a Gala underwater... 

The plant starts with twin-screw compounding of PP and glass fiber to produce a hot sheet, which is robotically transferred to a vertical compression press of 3300 tons. The fast-stroke press has automatic parallelism control. Another robot transfers parts to a 110-ton press that punches out attachment holes in the parts. Finally a third robot transfers parts to a machine that inserts hole reinforcements and inspects the parts. 

The ILC/D-LFT process starts with continuous glass rovings, PP, and other additives and feeds them Into a twin-screw compounding extruder. The glass becomes cut during processing... 

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