A PROCESS FOR RAPID CRYSTALLIZATION OF POLYESTERS AND CO-POLYESTERS VIA IN-LINE DRAFTING AND FLOW-INDUCED CRYSTALLIZATION

The present invention relates to a process for introducing strain-induced crystallization to polyesters. Specifically, amorphous polymer from the melt phase reactor is first extruded through a traditional strand die. However, instead of going directly into a pelletizer/cutter, it is stretched uniaxi...

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Bibliographische Detailangaben
Hauptverfasser:	DONELSON, MICHAEL, EUGENE, WEINHOLD, STEPHEN, SHELBY, MARCUS, DAVID, HALL, HARRY, PROBERT
Format:	Patent
Sprache:	eng ; fre ; ger
Schlagworte:	AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS MAKING GRANULES OR PREFORMS PERFORMING OPERATIONS PREPARATION OR PRETREATMENT OF THE MATERIAL TO BESHAPED RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIALCONTAINING PLASTICS SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR SHAPING OR JOINING OF PLASTICS TRANSPORTING WORKING OF PLASTICS WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL
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Beschreibung
Zusammenfassung:	The present invention relates to a process for introducing strain-induced crystallization to polyesters. Specifically, amorphous polymer from the melt phase reactor is first extruded through a traditional strand die. However, instead of going directly into a pelletizer/cutter, it is stretched uniaxially at a temperature only slightly higher than Tg. The chain alignment resulting from stretching makes crystallization occur at a considerably higher rate than with traditional thermal crystallization. After this stretching process, the strand is annealed and fed to the pelletizer and chopped. The process of the present invention is advantageous for crystallizing polymers having slow rate of thermal crystallization half time from the glass. Optically clear polymers having at least about 15% crystallinity and a single melting point endotherm are produced.