Heat treated polymer powders
AssigneeArkema Inc.
InventorsChristopher A. Bertelo, Manuel A. Garcia-Leiner, Anthony Decarmine, Scott F. Defelice
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Abstract
The invention relates to heat treatment of polymorphic semicrystalline or crystallizable polymers to increase the content of the highest melting crystalline form. Such heat treatment results in a polymer powder that has a consistent, uniform melting range, improved flow and improved durability of the powder particle size for applications that require powder flow at elevated temperatures. In addition to improved powder properties, the articles produced from the powders also exhibit better physical properties in both appearance and in mechanical properties. Thus the invention also includes polymer powders and articles produced by the described processes.
Claims10
A heat-treated polymer powder composition suitable for selective laser sintering, roto-molding or powder coating, said composition comprising at least two semicrystalline or crystallizable polyetherketoneketone polymorphs (X) and (Y) having at least two different melting points, wherein one of (X) or (Y) polymorphs is a highest melting crystalline polymorph relative to other semicrystalline or crystallizable polyetherketoneketone polymorphs in the polymer powder composition, and the other of (X) or (Y) polymorphs is a lower-melting crystalline polymorph,
- wherein the polyetherketoneketone comprises repeating units represented by Formulas I and II:
- —A-C(═O)—B—C(═O)— I(Isomer T)
- —A-C(═O)-D-C(═O)— II(Isomer I)
- where A is a p,p′-Ph-O-Ph- group, Ph is a phenylene radical, B is p-phenylene, and D is m-phenylene, wherein the T:I isomer ratio is in the range of from 60/40 to 80/20,
- whereby the content of the highest melting crystalline polymorph has been increased and/or maximized relative to the content of the other lower-crystalline polymorph in the polymer composition by heat treatment.
Dependencies are inferred from the claim text.