Polylactide resin and preparation method thereof
The present invention is directed to an organometallic complex and a catalyst composition capable of producing polylactide resins with improved properties at a higher conversion rate, a method of producing the organometallic complex, polylactide resins having enhanced hydrolysis resistance and heat resistance together with superior mechanical properties, a preparation process therefor, and polylactide resin compositions including the same.
1. A process for preparing a polylactide resin, comprising forming a catalyst composition comprising a complex between a compound of Chemical Formula 2 and a compound of Chemical Formula 3 prior to an initiation of polymerization; and subjecting lactide monomers to ring opening polymerization in the presence of the catalyst composition,
wherein
wherein n is an integer of 0 to 15, p is an integer of 0 to 2, M is Sn or Zn, R 1 and R 3 are the same as or different from each other, and each of them is hydrogen, a substituted or unsubstituted C3 to C10 alkyl, a substituted or unsubstituted C3 to C10 cycloalkyl, or a substituted or unsubstituted C6 to C10 aryl, R 2 is a substituted or unsubstituted C3 to C10 alkylene, a substituted or unsubstituted C3 to C10 cycloalkylene, or a substituted or unsubstituted C6 to C10 arylene, and each of X and Y is independently an alkoxy group or a carboxyl group.
2. The process for preparing a polylactide resin according to claim 1 , wherein the MX p Y 2-p is tin(II) 2-ethylhexanoate (Sn(Oct) 2 ).
3. The process for preparing a polylactide resin according to claim 1 , wherein R l is a monovalent phenyl group substituted with a C1 to C10 alkyl group or a C3 to C10 alkyl group or cycloalkyl group, and R 2 is a divalent phenylene group substituted with a C1 to C10 alkyl group, or a C3 to C10 alkylene group or cycloalkylene group.
4. The process for preparing a polylactide resin according to claim 1 , wherein the compounds of Chemical Formula 2 and Chemical Formula 3 are added at a ratio of 0.001 to 0.1 moles with respect to 100 moles of the lactide monomers, respectively.
5. The process for preparing a polylactide resin according to claim 1 , wherein the ring opening polymerization is carried out in the presence of an initiator comprising a compound with a hydroxy group.
6. The process for preparing a polylactide resin according to claim 5 , wherein the compound with a hydroxy group has 8 or more carbon atoms.
7. The process for preparing a polylactide resin according to claim 5 , wherein the initiator is added at a ratio of 0.001 to 1 mole with respect to 100 moles of the lactide monomers.
8. The process for preparing a polylactide resin according to claim 1 , wherein the ring opening polymerization is carried out in a manner of a bulk polymerization.
9. The process for preparing a polylactide resin according to claim 1 , wherein the ring opening polymerization is carried out at a temperature of 120 to 200° C. for 0.5 to 8 hours.