Hoechst Aktiengesellschaft

Uhde Inventa-fischer Gmbh

Arteva Technologies, S.a.r.l.

Thuringisches Institut Fur Textil Und Kunststoff-forschung E. V.

Rainer Schaller

Hilmar Mildenberger

Burkhard Sachse

Detlef Gneuss

Thomas Maier

Peter Braun

Eike Schulz Van Endert

Kurt Hanimann

Heinz Ehrhardt

Klaus Heinemann

Michael Frey

Ulrich Hertenstein

Eduard Lindner

Ralf Henke

Wolfgang F HÖLDERICH

Ralf-Peter GOTTLÖBER

Heinz Meierkord

Jürgen Musch

Axel Nechwatal

Mettu Anilkumar

The present invention relates to increasing the molecular weight during a thermal treatment of polyester in combination with a latent heat granulation. With the newly-developed method, an SSP (Solid State Postcondensation) can be directly combined with an underwater granulation. The method differs from a conventional solid state postcondensation by an increase in the molecular weight being possible without additional heat input and hence only by using the residual heat and the crystallization heat present. A characterizing element is improved water separation and dehumidification during the granulation. Only in this way is an increase in viscosity possible even with a small granulate of an average particle weight less than 20 mg.

Method for increasing the molecular weight of a polyester granulate by using its residual heat

A filter device for filtering plastic melts includes a filter wheel having cavities which are covered by screening elements. A pressure sensor is provided in a melt inflow line upstream of the filter wheel. A pressure sensor is also provided in a melt outflow line downstream of the filter wheel. The pressure sensors measure the pressure drop across the filter. The melt inflow and outflow lines are connected to a melt channel in the filter device, respectively. A melt return line is in connection via a pump and a discharge line with a backflushing slot. The discharge line is connected to an accelerator for increasing pressure in surges. A further melt return/discharge line is connected via a 3-way valve and a return line to the melt inflow line or to a disposal line.

Filter device for cleaning plastics melts

Process for isolating dimethyl 4,4'-biphenyldicarboxylate from residues of DMT production, which includes first distilling the residues at a pressure of at most 7 mbar at a boiler temperature from 200.degree. to 350.degree. C., subsequently treating the distillate which distills over in the range from 230.degree. to 270.degree. C. at a pressure of, for example, 0.2 mbar for from 10 to 60 minutes with 0.7 to 10 times the amount of an organic solvent at a temperature from 70.degree. to 180.degree. C., if required, separating the clear solution from undissolved components, cooling the removed clear solution to a temperature from 45.degree. to 65.degree. C. and allowing it to crystallize at this temperature, resulting in a suspension of dimethyl 4,4'-biphenyldicarboxylate crystals from which the crystals are isolated by washing one or more times with the same or a different solvent and by drying.

Isolation of dimethyl 4,4'-biphenyldicarboxylate

Compounds of the formula (I) ##STR1## in which n denotes a number from 2 to 6, m denotes 1 or 2,

Carbamoylimidazole derivatives and their use as fungicides

Growing community of inventors

Wertingen, Germany

Rainer Schaller