Method for stabilizing polymers containing repeating lactic acid units, and stabilized polymers so made
AssigneeNatureWorks LLC
InventorLaura M. Babcock
Life of this patent
Estimating the term…
Abstract
Metal catalyst residues in resins containing polymerized lactic acid units, such as polylactides, are deactivated by treatment with a polymer or copolymer that contain pendant acid groups and pendant ester groups, with an acid-containing PLA resin, or with a polymer or copolymer having at least one acid groups per 250 atomic mass units and which has pendant lactic acid or poly(lactic acid) groups. The deactivating agent is effective at deactivating the catalyst, and has little effect on the optical clarity of the resin.
Claims26
A process for deactivating metal-containing catalyst residues in a PLA resin, comprising contacting PLA resin containing residues of a metal-containing catalyst with a deactivating agent that includes (1) a polymer or copolymer having pendant acid groups and pendant ester groups wherein the polymer or copolymer contains from 2 to 50 mole percent of repeating units that contain pendant ester groups, (2) an acid-containing PLA resin that contains at least one acid group per 250 atomic mass units and at least one polylactic acid segment that has a weight of at least 1000 atomic mass units, (3) a polymer or copolymer having at least one acid group per 250 atomic mass units and which has pendant lactic acid or poly(lactic acid) groups, or (4) a mixture of any two or more of (1), (2) and (3).
4-6. (canceled)
10-12. (canceled)
15-17. (canceled)
A PLA resin composition comprising a) at least one PLA resin polymer having a number average molecular weight of from 25,000 to 500,000 containing residues of a metal-containing catalyst, and b) from 0.01 to 2 weight percent, based on the weight of combined weight of components a) and b), of a deactivating agent that includes (1) a polymer or copolymer having pendant acid groups and pendant ester groups, wherein the polymer or copolymer contains from 2 to 50 mole percent of repeating units that contain pendant ester groups, (2) an acid-containing PLA resin that contains at least one acid group per 250 atomic mass units and at least one polylactic acid segment that has a weight of at least 1000 atomic mass units, (3) a polymer or copolymer having at least one acid group per 250 atomic mass units and which has pendant lactic acid or poly(lactic acid) groups, or (4) a mixture of any two or more of (1), (2) and (3).
22-34. (canceled)
39-40. (canceled)
Dependencies are inferred from the claim text.