Patent ID: 9056946
Filing Date: 2015-06-16
Classification: C08G,C08L

Abstract:
1. A method for producing stereocomplex polylactic acid, comprising: (1) reacting glycerin with sodium hydroxide in high-temperature and high-pressure water to produce a racemic sodium lactate aqueous solution; (2) recovering racemic lactic acid by separating sodium from the racemic sodium lactate aqueous solution; (3) dimerizing the racemic lactic acid to produce a lactide mixture containing meso lactide and racemic lactide; (4) recovering racemic lactide by separating meso lactide from the mixture; and (5) polymerizing the racemic lactide with a salen-metal complex as a catalyst to produce stereocomplex polylactic acid, wherein the salen-metal complex is: wherein R1 and R2 each represent hydrogen, an alkyl group having from 1 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, a halogen group, a silyl group, an aryl group having from 6 to 18 nuclear carbon atoms, or a methoxymethyl group; R3 represents a divalent aliphatic hydrocarbon group having from 2 to 6 carbon atoms; and M represents Al, Fe, Ti or Y.