Paper Bag - Multiwall Paper Sacks

Multiwall Paper Sacks

Multiwall (or multi-wall) paper sacks or shipping sacks are often used as shipping containers for bulk materials such as fertilizer, animal feed, sand, dry chemicals, flour and cement. Many have several layers of sack papers, printed external layer and inner plies. Some paper sacks have a polyethyelene foil or polyethylene coated paper layer in between as a water-repellant barrier.

There are two basic designs of bags: open mouth bags and valve bags. An open mouth bag is a tube of paper plies with the bottom end sealed. The bag is filled though the open mouth and then closed by stitching, adhesive, or tape. Valve sacks have both ends closed and are filled through a valve. A typical example of a valve bag is the cement sack.