Continuous production of linear thermoplastic polyesters
Patent 4973655 Issued on November 27, 1990. Estimated Expiration Date: 
June 12, 2009. 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.
June 12, 2009. 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 ReferencesContinuous manufacture of polybutylene terephthalates Method for the preparation of oligomeric alkylene terephthalates Patent #: 4289895 InventorsAssigneeApplicationNo. 365125 filed on 06/12/1989US Classes:528/272, From di- or higher ester of a polycarboxylic acid as sole reactant, or from a polycarboxylic acid or derivative with a compound containing two or more hydroxyl groups or salts thereof528/300, Polyhydroxy-containing compound or salt thereof having an ether-oxygen atom as reactant528/301, Acyclic ether-oxygen compound528/308, Aryl-containing carboxylic acid or derivative of an aryl-containing dicarboxylic acid528/308.3, Processes of preparing528/484Preventing or removing reactor or processing equipment buildupExaminersPrimary: Kight, III, JohnAssistant: Acquah, Samuel A. Attorney, Agent or FirmForeign Patent References
International ClassC08G 063/88Foreign Application Priority Data1988-06-15 DEAbstractA process for the continuous production of linear thermoplastic polyesters comprises the following steps:(a) passing a transesterification or esterification product of an aliphatic or aromatic dicarboxylic acid having a molecular weight of <300 or an ester-forming derivative thereof with an aliphatic or cycloaliphatic diol having a molecular weight of <250 which may additionally contain a poly(alkylene oxide) glycol having a molecular weight of 400 to 4000 at from 250° to 360° C. under a pressure of 0.5 to 20 mmHg downward in the course of a residence time of from 3 to 10 minutes through an essentially upright tubular precondensation zone equipped with internal fitments having a free surface area of from 0.3 to 1.5 m2 /l to form a precondensate and a vaporous diol having a molecular weight <250,(b) separating into a precondensate and vaporous diol and(c) further condensing the precondensate in the bottom phase at from 240° to 290° C. under a pressure of from 0.5 to 20 mmHg in the course of a residence time from 10 to 40 minutes and dishcharging granulable polyester.Field of SearchFrom di- or higher ester of a polycarboxylic acid as sole reactant, or from a polycarboxylic acid or derivative with a compound containing two or more hydroxyl groups or salts thereofPolyhydroxy-containing compound or salt thereof having an ether-oxygen atom as reactant Acyclic ether-oxygen compound Aryl-containing carboxylic acid or derivative of an aryl-containing dicarboxylic acid Processes of preparing Preventing or removing reactor or processing equipment buildup | |
