Evonik Roehm Gmbh

Hans Baer

Michael Gottschalk

Gerhard Renner

Thomas Fuerst

Felix Hofmann

Silke Schminke

Julian Blaesy

Christian Brunnengraeber

Isabel Wahl

The invention refers to process for preparing a bio-resorbable polyester in particulate form, comprising the steps: a) providing a bio-resorbable polyester with in the form of a dry polymer mass or in the form of a wet polymer mass; b) feeding the polymer mass from step a) into an extruder extruder with at least one degassing zone where the polymer mass is molten, extruded and degassed; c) discharging the degassed polymer mass out of the extruder; d) comminuting the discharged polymer mass to particles with &#x2014;a bulk density of 0.3 g/ml or more, &#x2014;a tapped density of 0.4 g/ml or more and &#x2014;a specific surface area of 2.0 m/g or less.

Process for preparing a bio-resorbable polyester in particulate form

The invention refers to a Process for preparing a bio-resorbable polyester the form of a powder with a bulk density of 0.3 g/ml or more, a tapped density of 0.4 g/ml or more and a specific surface area of 2.0 m/g or less comprising the steps a. dissolving a bio-resorbable polyester in a first solvent to form a polymer solution, b. contacting the polymer solution with a second solvent which is a non-solvent for the bioresorbable polyester and which is mainly water to result the precipitation of the bio-resorbable polyester in the form of a wet polymer mass, c. pre-drying the wet polymer mass at a temperature below the Tof the bio-resorbable polyester, d. comminuting the pre-dried polymer mass to polymer particles with a size below 10 mm, e. drying the comminuted polymer particles below the Tof the bio-resorbable polyester to a residual water content of 1% or less by weight/weight, f. post-treatment of the polymer particles from step e at a temperature in the range from the Tto the Tof the bio-resorbable polyester, g. comminuting the polymer particles from step f to a powder with a particle size of dof 1-300 &#x3bc;m and dof more than 30 and up to 3000 &#x3bc;m.

Process for preparing a bio-resorbable polyester in the form of a powder

Growing community of inventors

Michelstadt, Germany

Hans Baer