United States Patent m
Narayan et al.
US005801224A [ii] Patent Number: [45] Date of Patent:
[54] BULK REACTIVE EXTRUSION
POLYMERIZATION PROCESS PRODUCING
ALIPHATIC ESTER POLYMER
COMPOSITIONS
[75] Inventors: Ramani Narayan; Mohan Krishnan, both of Okemos; Joseph B. Snook; Ajay Gupta, both of East Lansing, all of Mich.; Philippe DuBois, Ciplet. Belgium
[73] Assignee: Board of Trustees operating Michigan State University, East Lansing, Mich.
[21] AppL No.: 639,198
[22] Filed: Apr. 26,1996
[51] Int CL6 C08G 63/08
[52] U.S. CL 528/357; 528/358; 524/47
[58] Field of Search 528/357, 358;
524/47
[56] References Cited
U.S. PATENT DOCUMENTS
5,225,129 7/1993 van den Bag 528/357
5,286,770 2/1994 Basaaliettu — 524/52
5310,599 5/1994 Ford 528/354
5,412,005 5/1995 Bastiolietal 524/47
5,468,837 11/1995 Waotier 528/357
5,500,465 3/1996 Krisbnan et al 524/47
FOREIGN PATENT DOCUMENTS
626405 11/1994 European Pat. Off. .
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Primary Examiner—Tae Yoon
Attorney, Agent, or Firm—Ian C. McLeod
[57] ABSTRACT
A bulk extrusion polymerization process to derive an aliphatic polyester from a suitable ester monomer, preferably e-caprolactone. Novel reaction formulations containing less than 100 ppm water and having an acid value less than 0.5 mg KOH/g and preferably less than 0.2 mg KOH/g enable the polymerization of bulk monomer in an extruder in a resident time of less than 2 minutes. Different catalyst and initiator systems, processing protocols, and screw configurations lead to the preferred manufacture of poly(ecaprolactone) polymer of number average molecular weight, M„, greater man 100,000. A novel poly(e-caprolactone) intermediate optionally grafted to starch, is described which has significantly different processing and use characteristics as compared to a straight-chain polycaprolactone.
16 Claims, 6 Drawing Sheets
