Roehm Gmbh & Co Kg

Bernhard Schaefer

Uwe Numrich

Michael Meier-Kaiser

The invention relates to a method for regulating the minimal value of the pressure in the first half of the metering zone in a direction of conveyance in a single-screw degassing extruder or in a cascade extruder during the conveying of a melt consisting of a thermoplastic. The single-screw degassing extruder or the cascade extruder each have a first screw section (), a degassing zone (), a metering zone (), and a measuring control loop (M), which includes a pressure measuring sensor (P) in the first half of the metering zone, a regulator (R) and an actuator (S) for influencing the pressure in the metering zone. The pressure is measured by the pressure measuring sensor (P) and is set by the regulator (R) and the actuator (S) so that the minimal value at the location of measurement ranges from 0.1 to 10 bar.

Method and device for regulating pressure in a single-screw degassing extruder or in a cascade extruder

A film comprising at least one layer of fluorine polymers and poly(meth)acrylates is prepared by (i) preparing a mixture of fluorine polymer and poly(meth)acrylate; and (ii) extruding the mixture maintained below its gel-forming temperature through the die of an extruder having a filter placed before entry of the mixture into the die, the temperature of the die being maintained higher than the temperature of the composition upon entry into the die but lower than the gel-forming temperature of the mixture, onto a roll having a temperature &lE;100&deg; C., thereby forming the at least one layer in the shape of a film.

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Gross-Gerau, Germany

Bernhard Schaefer