Masterbatch boosts PLA’s melt strength by 3- to 5-fold

Teknor Apex has introduced a new melt-strength enhancer in masterbatch form that increases the pull force that can be applied to polylactic acid (PLA) by 300 to 500% over a wide range of drawdown ratios. As a result, higher throughputs in extrusion and thermoforming become possible, while scrap rates are reduced.

Terraloy MB-90001A1 melt strength enhancer broadens the processing window of PLA in cast film and sheet for clear end products such as clamshell containers used in produce packaging, food service takeout, and other applications. In thermoforming clamshell containers, a degree of force is required to force a hot sheet of plastic into a mold, and the deeper the mold cavity and the sharper the corners, the greater the force needed to fully shape the sheet into a finished container. At loading levels of 6 to 10%, the masterbatch dramatically increases the extensional force that can be applied to PLA during processing at drawdown ratios as high as 35:1.

"Poor melt strength has limited productivity in the processing of standard PLA and prevented use of the resin in certain applications," said Edwin Tam, manager of new strategic initiatives for the Bioplastics Division of Teknor Apex. "Besides overcoming these obstacles, the new Terraloy masterbatch disperses more efficiently and uniformly in PLA than additives that come in powder form and does not affect the clarity of neat PLA."