The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 28, 1998
Filed:
Apr. 02, 1997
Ben Duh, Tallmadge, OH (US);
Shell Oil Company, Houston, TX (US);
Abstract
A process is disclosed for the crystallization of a PEN prepolymer containing volatile components. The temperature is maintained in the range of about 20.degree. C. above the Tg and about 10.degree. C. below the Tm while the PEN prepolymer is agitated. The PEN prepolymer is present as chips or pellets. The crystallization is performed in the presence of a liquid or a mixture of liquids that do not degrade the polymer during crystallization. The liquid or liquids employed may be those whose vapor pressure at the amorphous PEN softening temperature are insufficient to forestall expansion of the pellets. When this class of liquid or liquids is employed, the crystallization vessel is pressurized with an inert gas, including air, to prevent the prepolymer expansion. If the liquid or liquids possess sufficiently high vapor pressures at the PEN softening temperature, the pellets do not expand even without the inert air pressurization.