Courier Bag Compound (PLA/PBAT, High Tear Strength)

About This Product

The compound is a melt-blended, film-grade pellet of polylactic acid and polybutylene adipate terephthalate for standard blown film lines at mailing-bag gauges. PLA is a rigid, notch-sensitive aliphatic polyester made by ring-opening polymerisation of lactide; PBAT is a soft, extensible aliphatic-aromatic copolyester dispersed through it at a controlled domain size. Courier bags fail at the seal and the seam, under point loading from whatever is inside them and from sortation equipment, so the governing property is resistance to a tear once one has started, not ultimate tensile strength. In neat PLA a crack begun at a weld or a staple simply runs; the dispersed PBAT domains stop it, because a crack front arriving at one blunts and draws, dissipating energy as plastic deformation across a wide zone instead of along a single plane. Raising the PBAT fraction and tightening domain size buys tear propagation and puncture resistance at the cost of clarity and stiffness, a deliberate trade, and leaves a film that takes the print and adhesive closures the format requires. It is used in courier and mailing bags, e-commerce despatch, blown film conversion and automated parcel handling. Bio Green Chem supplies the courier bag compound to specification on PLA/PBAT ratio, melt flow, film gauge and tear and puncture targets, as a raw material for processing on the buyer's own line; we do not produce finished articles.