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US 5,844,066 AGranted
Process for the preparation of lactic acid-based polyester
AssigneeDainippon Ink and Chemicals, Inc.
InventorYasutoshi Kakizawa
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AssigneeDainippon Ink and Chemicals, Inc.
InventorYasutoshi Kakizawa
Estimating the term…
The present invention provides a process for the preparation of a lactic acid-based polyester having an excellent moldability, storage stability and biodegradability which has a less residual lactide left therein and is less susceptible to decomposition of lactic acid-based polyester and attachment of sublimed lactide to the molding apparatus, etc. at the devolatilization step and molding step after the polymerization reaction of lactic acid-based polyester. In the present invention, an organic chelating agent is added to a lactic acid-based polyester to deactivate the esterification catalyst used in the preparation of the lactic acid-based polyester, making it possible to inhibit the decomposition of lactic acid-based polyester at the devolatilizing process and molding process after polymerization reaction. Accordingly, a process for the preparation of a lactic acid-based polyester useful as a packaging material such as film and sheet having a high molecular weight, a high heat resistance, good mechanical properties and excellent moldability, storage stability and biodegradability can be provided.
A process for the preparation of a lactic acid-based polyester, which comprises melt-kneading a lactic acid-based polyester with an organic chelating agent, wherein said lactic acid-based polyester comprises a lactic acid component and a polyester consisting of a dicarboxylic acid component and a diol component in a weight proportion of from 99/1 to 10/90 and said organic chelating agent is at least one member selected from the group consisting of carboxylic acids including a coordinated N atom and hydroxycarboxylic acids.
A molding process of a lactic acid-based polyester, which comprises adding an organic chelating agent to a lactic acid-based polyester, and then molding the mixture wherein said lactic acid-based polyester comprises a lactic acid component and a polyester consisting of a dicarboxylic acid component and a diol component in a weight proportion of from 99/1 to 10/90 and said organic chelating agent is at least one member selected from the group consisting of carboxylic acids including a coordinated N atom and hydroxycarboxylic acids.
Dependencies are inferred from the claim text.