Melt-stable lactide polymer composition and process for manufacture thereof

A method of producing a polylactide polymer composition comprising steps of:

• (a) polymerizing a mixture including lactide in the presence of a polymerization catalyst and at a temperature of greater than about 160.degree. C. to form polylactide polymer composition having a number average molecular weight of between about 10,000 and about 300,000;
• (b) introducing a catalyst deactivating agent into the composition to reduce catalytic depolymerization of the polylactide polymer, said catalyst deactivating agent being obtained from a carboxylic acid containing molecule;
• and
• (c) devolatilizing the polylactide polymer composition to provide a residual monomer concentration of less than 2 wt % based on the weight of the composition.

A method for processing a polylactide polymer composition and comprising steps of:

• (a) providing a polylactide polymer composition comprising:
• (i) polylactide polymer having a number average molecular weight in the range of about 10,000 to about 300,000;
• (ii) residual monomer, if present at all, present in a concentration of less than 2 wt %;
• (iii) residual polymerization catalyst for polymerization of polylactide polymer;
• and
• (iv) catalyst deactivating agent, wherein:
• (A) said catalyst deactivating agent is provided in an amount sufficient to reduce catalytic depolymerization of the polylactide polymer;
• and
• (B) said catalyst deactivating agent obtained from a carboxylic acid containing molecule;
• and
• (b) melt processing the polylactide polymer composition by heating the polylactide polymer composition to a temperature of at least 180.degree. C. and extruding the melted polylactide polymer composition.