Process for the preparation of polyester-masterbatch containing finely divided additives
AssigneeZimmer, Inc.
InventorsDieter Zickler, Ulrich Thiele
Life of this patent
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Abstract
Process for the manufacture of a polyester masterbatch containing finely divided solid additives in homogenous and agglomerate-free distribution, through the mixing, within a homogenizing extruder, of the powdery additive into the polyester, whereby, separately from the addition of the additive, small quantities of a diol are additionally fed into the extruder.
Claims9
In a process for making a polyester masterbatch containing 2-70 weight % /f finely divided solid additives in homogeneous and agglomerate-free distribution comprising providing a homogenizing extruder having a feed end and a discharge end, introducing a polyester into said feed end, said polyester having a predetermined intrinsic viscosity of at least 0.5 dl/g which includes the steps of
- a) adding said additive in the downstream direction at a point along said extruder representing 15-40% of the residence time said polyester is in the extruder, the total residence time being equal to 100%,
- b) adding separately from said additive, and in the downstream direction before the point of said additive addition, approximately 0.01 to 5.0 mol of a diol per mol of polyester to reduce said predetermined intrinsic viscosity by 1 to 70%, measured at said discharge end, said steps being performed in the absence of substances capable of reaction with said polyester, said diol or said additive.
Dependencies are inferred from the claim text.