US 11,905,407 B2 · Polylactide-based masterbatch, for a commercially viable single-step in-mold annealing injection molding process

Abstract

Polylactide (PLA) parts can be crystallized via two procedures. In the first procedure, i.e. a 2-step post-mold annealing process, the complete crystallization of PLA parts can be done after molding in a secondary operation called as post-mold annealing to make higher heat-resistant PLA parts. There are limitations to this 2-step operation, namely, a) warpage of parts with complex geometries, and b) scaling up higher production volume times. In the second procedure, i.e. 1-step in-mold annealing process, the complete crystallization of PLA parts can be done in the mold itself by holding the temperature of the mold at the crystallization temperature of PLA which is about 100° C. The 1-step in-mold annealing process using a masterbatch blended with neat PLA results in a highly crystalline article produced in a significantly lower cycle time.

Claims20

Dependent claims

A process comprising:

in-mold annealing in a 1-step a polymer blend and forming an article, said polymer blend comprising,
a) 100 parts by weight of a neat polylactide resin having a weight average molecular weight of from about 110,000 to about 175,000, said neat polylactide resin having a d (dextrorotatory) content of from about 0.2% to about 1.0%, and
b) from about 10 to about 100 parts by weight of a masterbatch, said masterbatch comprising from about 15 wt. % to about 50 wt. % of a polylactide resin having a weight average molecular weight of from about 110,000 to about 175,000, from about 30 wt. % to about 70 wt. % of a crystallization aid compound comprising a salt of a sulphonate, or a salt of a phosphonate or a salt of a silicate, from about 5 wt. % to about 30 wt. % of a compostable random copolyester, and wherein said cycle time to produce said article is from about 20 to about 50 seconds for a 5 gram molded article.

A composition comprising:

a) 100 parts by weight of a neat polylactide having a weight average molecular weight of from about 110,000 to about 175,000, said neat polylactide having a d (dextrorotatory) content of from about 0.2% to about 1.0%,
b) from about 10 to about 100 parts by weight of a masterbatch, said masterbatch comprising from about 15 wt. % to about 50 wt. % of a polylactide, from about 30 wt. % to about 70 wt. % of a crystallization aid compound, and from about 5 wt. % to about 30 wt. % of a compostable random copolyester, said masterbatch polylactide having a d (dextrorotatory) content of from about 0.2% to about 2.5%, and said composition capable of being molded in a single step and having a crystallinity of at least 45%.

Dependencies are inferred from the claim text.

Facts

Application

17/604,103Filed 13 May 2020 · us provisional application

Priority

17 May 2019

Published

US 2022/0204755 A130 Jun 2022

Granted

20 Feb 2024

Term ends

Not estimatedThe source records don’t support an estimate.

Classification27 codes

C08L 67/04
Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain ; Compositions of derivatives of such polymers:…
B29C 45/0001
Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor: characterised…
B29C 45/0013
Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor: using fillers…
B29C 71/02
After-treatment of articles without altering their shape; Apparatus therefor: thermal after-treatment

Polylactide-based masterbatch, for a commercially viable single-step in-mold annealing injection molding process

Life of this patent

Polylactide-based masterbatch, for a commercially viable single-step in-mold annealing injection molding process

Life of this patent

Abstract

Claims20