Kraft Paper - Qualities

Qualities

• Normal kraft paper is strong and relatively coarse. It has high tensile strength. The grammage is normally from 40–135 g/m2.

• Sack kraft paper, or just sack paper is a porous kraft paper with high elasticity and high tear resistance, designed for packaging products with high demands for strength and durability.

• Absorbent kraft paper is made with controlled absorbency, i.e., a high degree of porosity. It is made of clean low kappa hardwood kraft and has to have a good uniformity and formation.

• Spinning kraft paper is an especially strong type of kraft paper with relatively low grammage (40 g/m2). This paper requires the best possible machine direction strength and cross machine elongation. This is done by high fiber orientation on the papermachine.

• Hunting cartridge paper is a kraft paper used in shotgun shells. This paper needs a high tensile strength in the machine direction, which is the axial direction of the cartridges. In the cross direction, the cartridge is supported by the gun-pipe, but a sufficient elongation is needed. The body of the cartridge is wound of a kraft paper of 80–120 g/m2, which is further covered by an outer sheet of 60–80 g/m2 with colour and printing.

• Candy wrapping paper or twisting paper are thin 30–40 g/m2 kraft papers and is mostly flexo or offset printed. These papers requires a good strength, with highly oriented fibers. Twisting paper is mostly opaque and often supercalendered.