Foam crystallization of condensation polymers
Patent 4224264 Issued on September 23, 1980. Estimated Expiration Date: 
January 18, 1999. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
January 18, 1999. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3036991 3227784 3384696 3585259 3586647 Polyester granule for melt-shaping and process for the preparation thereof Foamable structural thermoplastic polyester resins Thermoplastic formable blends, a foaming method and products made thereby Patent #: 4097425 InventorsApplicationNo. 06/004433 filed on 01/18/1979US Classes:264/54, Chemical blowing264/141, Subsequent to extruding step264/85, UTILIZING SPECIAL INERT GASEOUS ATMOSPHERE OR FLUSHING MOLD WITH INERT LIQUID521/182, Cellular product derived from a -C-C(=X)-X containing reactant wherein X is a chalcogen atom, e.g., phthalic acid, etc.521/79Extruding a solid polymer containing material to form a cellular productExaminersPrimary: Anderson, PhilipAttorney, Agent or FirmInternational ClassesC08J 9/36 (20060101)C08J 9/00 (20060101) AbstractA normally amorphous condensation polymer is crystallized by foaming it with a chemical blowing agent at a temperature above the softening point of the polymer, extruding the molten polymer to form a solid foam and maintaining the foam at a temperature above the glass transition temperature until crystallization occurs. The crystallized polymer foam may be used as a structural foam. It can be used in solid state polymerization to obtain polymers of enhanced degree of polymerization.Other References
| |
