Back to results
US 6,297,315 B1Granted
Process for preparing polytrimethylene terephthalate
AssigneeShell Oil Company
InventorsBen Duh, Ye-Mon Chen, Ann Marie Corey
Life of this patent
Estimating the term…
Abstract
The pelletized product of melt condensation polymerization of 1,3-propanediol and terephthalic acid (or alkyl ester thereof) is crystallized by immersion in water at a temperature within the range of 60 to about 100° C. Hot-water treatment increases the crystallinity of the polymer to at least about 35% and increases pellet density to about 1.33 g/cm3.
Claims10
A process for reducing the self-adhesiveness of polytrimethylene terephthalate pellets comprising the steps of:
- contacting melt-phase-polymerized polytrimethylene terephthalate pellets having an intrinsic viscosity of at least 0.4 dl/g with an aqueous liquid at a temperature within the range of 60 to 100° C. for a time sufficient to induce a degree of crystallinity of 35% to 45% in the polytrimethylene terephthalate pellets.
Dependencies are inferred from the claim text.