Fertilisers containing free acid should be packed in

Fertilizers containing free acid should be packed in HDPE bags as these are water resistant with poor air permeability, safe and resistant to chemicals.
HDPE is High-density polyethylene, these are plastic bags are undoubtedly the most common in the world. The chemical composition of HDPE features long chains of straight molecules that are very linear from start to finish, HDPE polymers have minimal branching.