Process for preparing a resorbable polyester as a granulate or powder by bulk polymerization

A process for preparing a bio-resorbable polyester as a granulate or powder by bulk polymerization of one or more monomer(s), the process comprising a) to g):

• a) filling a monomer granulate having a mean particle size in a range from about 0.5 to 3 mm, comprising the one or more monomer(s), into a container,
• b) adding a polymerization catalyst and a chain length moderator on top of the monomer granulate,
• c) adding further of the monomer granulate on top of the polymerization catalyst and the chain length moderator,
• d) closing the container,
• e) carrying out a polymerization reaction in the closed container at a temperature in the range of 50° C. to 170° C., wherein a solid polymer in the form of a polymer block is formed,
• f) removing the polymer block from the container, and
• g) comminuting the polymer block to a granulate or powder,
• wherein the container is an unstirred container,
• wherein b) and c) are carried out once or are repeated, and
• wherein a) to e) are carried out under inert atmosphere.