Conversion of contaminated polyethylene terephthalate to decontaminated polybutylene terephthalate
September 1, 2020. 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 3859257 Polybutylene terephthalates having a low carboxyl content and continuous process for the production thereof Process for the continuous production of polybutylene terephthalate of high molecular weight Method for producing polybutylene terephthalate Process for the production of PBT carpet yarn Process for increasing the direct esterification reaction rate of a diacid with a glycol Process for preparing polybutylene terephthalate from pet scrap Process for the conversion of poly(ethylene terephthalate) waste to poly(alkylene terephthalate) Patent #: 5451611 InventorAssigneeApplicationNo. 623388 filed on 09/01/2000US Classes:521/48.5, Treating with alcohol521/48Treating polyesterExaminersPrimary: Cain, Edward J.Assistant: Lee, Katarzyna W. Attorney, Agent or FirmForeign Patent References
International ClassC08J 011/04Foreign Application Priority Data1998-03-27 AUAbstractDecontaminated crushed polyethylene terephthalate is converted to decontaminated PBT withtout requiring a catalyst by mixing with 1,4-butanediol under reduced pressure, transeterifying at 120-190° C., distilling off ethanediol and tetrahydrofuran under sub-atomspheric pressure. The method lowers costs, and decreases wasteful by-products and removes contaminants present in post-consumer PET, (e.g. paper, pigments, plastics, dyes, mineral sands, and clays) and chemical and water insoluble contaminants.Field of SearchContaining hydroxyl groupTreating polyester Treating with alcohol Clay, e.g., fullers earth, fire clay, etc. Mixing with carbon, e.g., graphite, etc., having numerical limitations, other than amount, e.g., included herein are particle size, surface area, etc., or composition or product thereof, DNRM | |
