Control of thermoplastic polymer crystallization by moisture level control useful for controlling the crystallization of polyesters, e.g. polyethylene terephthalate, polyethylene napthalate, or polybutyene terephthalate

摘要

A process for crystallization of at least partially amorphous thermoplastic polymer material obtained from a polymer melt, in which before crystallization the polymer material is subjected to one or more conditioning steps, in which a controlled moisture level and/or a controlled moisture profile is set up in the material. During crystallization of partially amorphous thermoplastic polymers, in spite of careful temperature control agglomerate formation via pellet formation and/or formation of pellets with their breaking open on the crystallizer walls can occur when the conditions of granulate formation are unsuitable and/or because of unsuitable bedding of the granulate prior to crystallization, and this can be hindered by controlling the moisture content. A process for crystallization of at least partially amorphous thermoplastic polymer material obtained from a polymer melt, in which before crystallization the polymer material is subjected to one or more conditioning steps, in which a controlled moisture level and/or a controlled moisture profile is set up in the material.