Single screw plasticating extrusion

In the past with the development of single-screw extrusion techniques for newer TP materials, it was found that some plastics with or without additives required higher pressures (torque) and needed higher tempera-... 

Currently, organic pigments can be mixed into plastics in concentrations of 40-50 %, and inorganic pigments up to 75 %, with good dispersing quality by means of single-screw extrusion [48]. 

Extrusion, autothermal (autogenous extrusion, adiabatic extrusion) n. An extrusion operation in which the entire increase in enthalpy of the plastic, from feed throat to die, or very nearly all of it, is generated by the frictional action of the screw. In such an operation, which most commercial single-screw extrusions approach closely, the functions of the barrel heaters are to preheat the machine at startup and, during steady operation, to prevent heat loss from the plastic through the barrel to the surroundings. 

Thompson, M. R., G. Donoian, and J. R Christiano, Examinations of Starve-Fed Single Screw Extrusion in Conventional and Barrier Feed Screws, 57th Annual Technical Conference of the Society of Plastics Engineers, 1999, p. 145. 

ET Screw, Single screw extrusion, blow molding, and injection molding, Barr, Robert, Inc. Ethacure, Liquid aromatic diamine epoxy, and urethane curatives, Albemarle Ethafoam, Polyethylene foam, Dow Plastics Ethanox, Hindered phenolic antioxidants, Albemarle... 

Fig. 6 A cross section of a single-screw extrusion-cooker 1 engine, 2 feeder, 3 cooling jacket, 4 thermocouple, 5 screw, 6 barrel, 7 heating jacket, 8 head, 9 net, 10 cutter, I transport section, n compression section, /// melting and plasticization section. Reproduced with permission from Moscicki et al. (2013). All published manuscripts are licensed undta- a Creative Commons Attribution 3.0 Unported License...

Plastic material transport is different in a twin-screw than in a single-screw extruder. In single-screw extrusion, plastic is conveyed with a drag-induced type or transport. In a twin-screw extruder, plastic... 

Before examining the technology involved in mixing during single screw extrusion of plastics products, the extruder s role in the overall scheme from individual materials to finished extruded composition needs considering. 

Feed rates With twin screw extrusion, much attention is paid to controlling the feed rate of the plastic to the machine, so as to minimize disruptions in the continuous stream of molten plastic to the die. With single screw extrusion and molding, gravity typically provides adequate control of the feeding process. 

Stevens, M. J., Extruder Principles and Operation , Elsevier, New York, 1985. The book summarizes the principles of single screw extrusion processes for plastics and rubbers, practical performance and operating procedures. 

Tadmor, Z., Fundamentals of Plasticating Extrusion, Polym. Eng. Set, 6, 185 (1966) Potente, H., Single-Screw Extruder Analysis and Design, Chapter 5 in Screw Extrusion, White, J. L. and Pontente, H. (Eds.), Hanser, Munich (2003)... 

In the method of producing a hollow foamed plastic body from polyethylene or polypropylene by means of an extrusion blow-moulding process using a single-screw... 

Screw extruders usually are built with a single screw as shown, but may have as many as four screws and the die may have multiple holes of various cross sections. An 8 in. dia screw can have a capacity of 2000 Ib/hr of molten plastics. Tubing can be extruded at 150-300 ft/min. To make pellets, the extrudate goes to cutting machines in which parts as small as washers can be made at rates as high as 8000/min. The extrusion of plastics is described at length by Schwartz and Goodman (Plastics Materials and Processes, Van... 

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