Method for forming a low viscosity polyarylene sulfide
AssigneeTicona LLC
InventorsVenkata M. Nekkanti, Hendrich A. Chiong, Jacob Grayson
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Abstract
A method for washing a polyarylene sulfide with a washing solution that contains a carefully controlled solvent content is provided. More particularly, the washing solution typically contains water (e.g., deionized water) in an amount of from about 30 wt. % to about 70 wt. % and an aprotic organic solvent in an amount of from about 30 wt. % to about 70 wt. %. Within such carefully controlled ranges, the present inventors have discovered that the polyarylene sulfide can retain a relatively high oligomer content, which in turn, helps minimize the melt viscosity.
Claims18
A method for forming a washed polyarylene sulfide, the method comprising contacting a slurry of a polyarylene sulfide with a washing solution within a vessel in which the slurry of the polyarylene sulfide enters the vessel at a slurry inlet that is located such that solids of the slurry flow via a gravity flow from the slurry inlet to a solids outlet and in which the washing solution enters the vessel at a liquid inlet and flows counter current to the gravity flow of the solids to a liquid outlet that is above the slurry inlet, wherein the washing solution contains from about 30 wt. % to about 70 wt % of water and from about 30 wt. % to about 70 wt. % of an aprotic organic solvent, wherein the washed polyarylene sulfide has an oligomer content of from about 0.5 wt. % to about 2 wt. % and a melt viscosity of about 2,350 poise or less, as determined in accordance with ISO Test No. 11443:2005 at a shear rate of 1200 s−1 and at a temperature of 310° C.
Dependencies are inferred from the claim text.