What types of bags are we talking about?
Lighter paper bags that are used to carry groceries, fast-food take-outs, over-the-counter goods, wine and liquor.
Heavier multi-wall sacks (stronger packaging used for products such as sugar, flour, cement, seed, fertiliser, animal feed). Multi-wall sacks are also widely used for leaf and yard waste and for organic (food scrap) collection from households. Kraft paper also has a wide range of other uses: as envelopes, file folders, butcher paper, grease-resistant paper, and as air-filled dunnage bags for transporting cargo.
What are paper bags made from?
Paper bags can be made from either kraft pulp (kraft is the German word for strength) or recycled pulp, or a blend of the two. Two kraft pulp mills in Canada use wood chips and sawmill residues as their prime raw material. A third mill that recently closed used predominantly recycled fibre (old boxes collected from supermarkets and factories or from curbside). Sometimes pulp made from wood chips and sawmill residues is added to recycled pulp, to give more strength to the bag.
How are they made?
At the mill, the wet pulp is made into paper and dried on a large, fast paper machine. The rolls which are produced are then sold to a converter who transforms the paper into the required packaging design via printing, slotting, creasing, folding and gluing. Then a brandowner customer or a packager fills the package with product prior to distribution to industry or the public. Any waste material left over from the converting process is collected on-site and sold to paper recycling mills for further use.
Where are they made?
The two Canadian mills making unbleached kraft paper for bags are located in Prince George, British Columbia and The Pas, Manitoba. Kraft paper converters are located all across Canada. A lot of bag material also comes north from US mills and converters.