| 摘要 |
PCT No. PCT/GB95/02257 Sec. 371 Date Sep. 22, 1997 Sec. 102(e) Date Sep. 22, 1997 PCT Filed Sep. 21, 1995 PCT Pub. No. WO96/09402 PCT Pub. Date Mar. 28, 1996A hydroxycarboxylic acid copolyester of R-stereospecific configuration contains a majority of first repeating units capable of forming a highly crystalline high-melting homopolyester and a minority of second repeating units capable when randomly copolycondensed with said first repeating units of lowering the melting point of said homopolyester and is characterised by one or more of: higher crystalline melting point, shorter crystallising time, higher notched impact strength at age 1 month, as compared with corresponding random polyester, and said majority repeating units in the polyester chain being present in blocks longer than correspond to their over-all molar proportionality. The copolyester may be made by fermentation, controlling the distribution of repeating units by reference to the pattern of feeding substrates corresponding to the respective repeating units. |
