Extrusion temperature profile

The blend was either pelletized on a Modern Plastics Machinery 1" extruder at 500°F or 550°F for 1, 2, 3, 4 and 5 extrusions. Samples of each formulation were collected after the first, third and fifth extrusions. The extrusion temperature profile was kept as follows ... 

Polyaryl ether ketones may be processed on conventional injection moulding and extrusion equipment, providing sufficiently high temperatures can be achieved. Melt temperatures required are typically 370°C for unreinforced PEEK, 390°C for reinforced PEEK and both unreinforced and reinforced PEK and unreinforced PEEKK, and 410°C for reinforced PEEKK. For the latter material a temperature profile from feed zone to nozzle would be... 

Most of the compounds were extrusion compounded in a conical, partially intermeshing, counter rotating twin screw extruder (Haake Reomix TW-lOO). The extruder speed was set at 50 rpm and the barrel temperature profile was set to produce a melt temperature of 260°C at the die. Samples were injection molded in a 31.8 MT Battenfeld press with a 59 cc shot size. Where noted, samples were compounded in a 60 cc Brabender internal mixer and compression molded. 

Onwulata, C. 1., Konstance, R. P., Phillips, J. G., and Tomasula, P. M. (2003b). Temperature profiling Solution to problems of co-extrusion with whey proteins. /. Food Process. Preserv. 27,337-350. 

The baseline extrusion process was numerically simulated using the processing conditions in Table 9.4 and the method described in Section 9.2.1, that is, with a rate of 77 kg/h, a screw speed of 27 rpm, and a discharge pressure of 10.6 MPa. The iterative calculation process was used to estimate a bulk temperature of 160 °C and a pressure of 13.1 MPa at the entrance to the meter section. The axial pressure and temperature profile for the simulation is shown in Fig. 9.5. 

Axial screw temperature profiles have been measured before, but they have been limited by the number of sensors and the quality of the data. The data presented here expand the existing knowledge of extrusion and also provide a new method for determining the ending location of the solid bed. 

Keum, J. and White, J. L., Heat Transfer Coefficients and Screw Temperature Profiles in Modular Twin Screw Extrusion Machines, SPE ANTEC Tech. Papers, 50,108 (2004)... 

Experimentators managed to produce thin films from all polymers under investigation but their thickness differed with certain regularities despite the fact that the films were produced at different laboratories and on different equipment. The shape of sleeve and temperature profile over sleeve length also differed significantly, as well as the specific impact elasticity of films both along and transverse to the direction of extrusion. 

Generally speaking, the appearance of the pipes and profiles was fairly good it was still noted that the extrudate appearance improves considerably, extrusion temperatures being the same, by operating with screw rotation speeds shifted toward high values. 

A typical example of a tubular reactor for one-step processing of a newly synthesized polymer is described in a number of patents.183,184 This device consists of a high-pressure tube with the temperature profile regulated along its length. An extrusion die is mounted at the outlet end of the reactor. Continuous feeding is provided by a piston pump. 

H. Zamodits, Extrusion of Thermoplastics, Ph.D. Thesis, University of Cambridge, 1964 also H. Zamodits and J. R. A. Pearson, Flow of Melt in Polymer Extruders, Part 1. The Effect of Transverse Flow on a Superimposed Temperature Profile, Trans. Soc. Rheol., 13, 357 (1969). 

To improve properties such as mechanical, thermal, and dimensions of certain molded TSs, also certain TPs, they are exposed to a postcure. The part is literally baked in an oven. Experience or a material supplier s recommended times and temperature profiles required to enhance properties are used. Baking also improves creep resistance and reduction in stresses. This postcuring is also used with certain TPs after IM or extrusion to improve their performance. 

Extrusion conditions feed rate, 800 g min", screw speed, 300 rpm twn Aes, 4 mm diameter, barrel temperature profile, 25/55/120/150/150°C from feed port to die. From Guy and Home (1988) with permission. 

Processing. SAN copolymers may be processed using die conventional fabrication mediods of extrusion, blow molding, injection molding, diennofomiing, and casting. Small amounts of additives, such as antioxidants, lubricants, and colorants, may also be used. Typical temperature profiles for injection molding and extrusion of predried SAN resins are as follows (101). 

Extrusion of tubes, hose, and profiles is done on standard extruders for rubber. The usual temperature pattern is a gradual increase of temperature from the feed zone to the die. The die temperature is typically 100°C (212°F), and the screw temperature is approximately the same as the temperature of the feed zone [44]. Processing aids are almost always required to improve the surface appearance and to increase the extrusion rate. Extrusion represents only a small proportion (about 10%) of the total consumption of fluorocarbon elastomers [52].Cold feed extruders typically used for extrusion of rubber stocks are also suitable for the extrusion of fluorocarbon elastomers. Extrusion should be carried out at temperatures below 120°C (250°F) to avoid scorch. In most cases a breaker plate and screen pack are used to generate backpressure on the screw and to remove foreign particles from the stock. A straight head is used for the extrusion of profiles or tubing, whereas a cross-head die is used for... 

In reactive polymerization it is important to control extrusion conditions (extruder profiles, temperature profiles, residence times) as well as having a good understanding of the polymerization kinetics, thermodynamics and properties (i.e. reaction rates, conversion times, heats of polymerization, ceiling termperatures of the polymerization reactions, viscosity (M ) changes). All of the processes discussed in Section 1.2 are brought to bear in the environment of the extruder. 

After mixing, preconditioned materials are discharged into an extruder. The final product characteristics are affected by screw and barrel profiles, screw speed, processing conditions (temperature, moisture content, etc.), raw material properties, and die/knife type. A single-screw extruder is used in 85%-90% of all semimoist pet food production. All equipment requires stainless steel construction due to low pH (4.0-4.5) of most formulas. The extrusion temperature is maintained... 

The reactive extrusion is a process demanding precise operation by well-trained personnel. The knowledge of the extruder, compounding and mixing principles, design of screw and temperature profile, local residence time distribution, etc., is required. For optimization of the reactive extrusion in- or on-line process monitoring, control, and data logging are recommended — this imposes further demands on the extruder operator. 

Description A variety of LDPE homopolymers and copolymers can be produced on these large reactors for various applications including films, molding and extrusion coating. The melt index, polymer density and molecular weight distribution (MWD) are controlled with temperature profile, pressure, initiator and comonomer concentration. Autoclave reactors can give narrow or broad MWD, depending on the selected reactor conditions, whereas tubular reactors are typically used to produce narrow MWD polymers. 

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