Kraft Paper

Kraft paper is a durable paper material produced using the kraft pulping process. The term “kraft” means strength. Manufacturers cook wood chips with sodium hydroxide and sodium sulfide to remove lignin while preserving long cellulose fibers. These long fibers create high tear resistance and structural integrity, which makes kraft paper ideal for packaging.

What It Is and How It Is Made

During the kraft process, wood chips are processed under heat and pressure. The chemical solution separates strong fibers from the wood structure. The pulp is then washed, screened, and formed into sheets. Manufacturers may leave the paper unbleached, which results in the familiar brown color, or bleach it for a white surface.

There are several common variations:

Unbleached kraft paper usually offers the highest fiber strength. Bleached kraft improves visual appearance but slightly reduces fiber strength due to additional processing.

Why It Matters in Packaging

Kraft paper plays a key role in packaging because it combines mechanical strength and sustainability perception. Long fibers improve tear resistance. So paper bags made from kraft can carry heavier loads without breaking. Corrugated cartons often use kraft linerboard as the outer layer because it protects products during transport.

Many brands prefer natural brown kraft because it signals environmental responsibility. When sourced with FSC certification, kraft paper supports responsible forestry claims. Compared with coated art paper, kraft paper has lower surface smoothness but stronger structural performance. Compared with standard recycled paper, virgin kraft generally provides better tensile strength.

How It Is Applied in Production

In packaging manufacturing, kraft paper is used in several ways. Factories convert it into shopping bags, mailing envelopes, wrapping sheets, and corrugated liners. In rigid box production, kraft paper can wrap greyboard to create a natural look while maintaining structural strength.

GSM selection depends on load requirements:

Kraft paper also supports finishing processes such as hot stamping, embossing, flexo printing, and screen printing. However, because of its absorbent surface, color brightness may appear lower than on coated paper unless white ink or surface treatment is applied.