Multi-layer kraft paper bags

A multi-layer kraft bag carries weight and grease at the same time. Charcoal, granular goods, coffee and pet food all put a bag under load while the contents try to migrate through the paper. Layer count, the inner ply and the bottom construction decide whether the bag holds.

Why more than one layer

A single ply of kraft at 120 gsm will carry a light retail purchase but not 2 kg of granules. Two and three-ply constructions combine plies of different grades so that strength, print surface and grease resistance are provided by different layers rather than compromised in one. The outer ply takes the print; the inner ply takes the load and the contact.

Grease and moisture resistance

Kraft absorbs oil. For charcoal, coffee or anything with free fat, an inner barrier is required: a PE coating, a laminated film, or a grease-resistant inner ply. Without it, the bag wicks oil to the outside within days and the print darkens. If the product also needs moisture protection, the same inner layer does both jobs.

Bottom and side construction

The bottom is where a heavy bag fails. A folded and glued square bottom spreads the load across the full footprint; a simple pinch bottom concentrates it and splits. Side gussets add volume without increasing the footprint, and a reinforced top edge keeps the opening from tearing when the bag is carried by a folded-over top.

Handles and load

Twisted paper handles glued to the inner face of a multi-layer bag carry more than handles glued to the outer surface, because the load passes into the plies rather than through the print layer. Above roughly 4 kg, reinforcement patches at the handle anchor are not optional.

Print on kraft

Uncoated kraft absorbs ink, so solids print softer and fine reversed-out type fills in. Design on the actual stock colour rather than on white - a colour that looks right on screen shifts warm on brown kraft. For a rich solid, a white underprint layer is what makes it opaque.

Minimum order and lead time

Paper bags start at 100 pieces. Sampling is 1–3 pieces and takes 2–3 working days; bulk production runs 7–15 working days after approval. Digital printing on short runs can ship in 48 hours.

Send the fill weight, whether the contents are greasy or damp, and the quantity. Layer structure and inner barrier are specified from those two answers.