Polyester composition

• Main Author: LIGGAT; JOHN JAMIESON
• Format: Patent
• Language: English
• Published: 02.12.1997
• Edition: 6
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; GENERAL PROCESSES OF COMPOUNDING; MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONSONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; WORKING-UP

PCT No. PCT/GB94/01095 Sec. 371 Date Apr. 17, 1996 Sec. 102(e) Date Apr. 17, 1996 PCT Filed May 20, 1994 PCT Pub. No. WO94/28070 PCT Pub. Date Dec. 8, 1994A polyester composition comprises at least one first semi-crystalline or crystallizable polyhydroxyalkanoate (PHA-X) and at least one second polyhydroxyalkanoate (PHA-Y) in semi-crystalline or crystalline form and having a higher crystalline melting point than said PHA-X. The PHA-Y is prepared by an annealing treatment in which the crystalline melting point is raised preferably by at least 5 DEG C. compared to the PHA-X and preferably by at least 3 DEG C. compared to the PHA-Y prior to the annealing treatment. The PHA-X and PHA-Y are preferably selected from polyhydroxybutyrate and polyhydroxybutyrate-co-valerate.