PLA-PPG-PU Block Copolymers

Title: LACTIDE COPOLYMER, METHOD FOR PREPARING SAME, AND RESIN COMPOSITION COMPRISING SAME

 Number/Link:US2015/0284516

Applicant/Assignee: LG Chem

Publication date: 8-10-2015 (Priority PCT/KR)

Gist”: Polyether-polylactide block copolymers are prepared using ROP and then extended with isocyanates

Why it is interesting: Polylactic acid (PLA) is a well known renewable and biodegradable polymer often used in the form of films or sheets for disposable packaging. The polymer is however not very flexible and the films have poor mechanical properties. According to this invention both flexibility and mechanical properties can be greatly improved by making polyether-polylactide copolymers and then extending these using an isocyanate with a functionality of more than 2. The copolymers are made by ring-opening polymerization of lactide monomer using a polyether diol as a ‘macro’ initiator together with a specific catalyst. In the examples an excess L-lactide monomer is used which is reacted with a 4000 to 6000 mole weight polypropylene glycol, resulting in a block copolymer with a Mw of more than 100,000.  The block copolymer is then reacted with a mixture of MDI and hexamethylenediisocyanate isocyanurate, after which the residual lactide is removed.

L-Lactide

L-Lactide

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