Corrugated cardboard base paper specification-medium and liner

The raw material for corrugated cardboard contains variety kinds of paper ：

• corrugated medium
• test liner
• kraft liner
• white top liner

corrugated medium is corrugated in the single facer , then glued with liner formed to single face corrugated board, and different kinds of liner is used in different industry. Kraft liner corrugated board is top grade packaging material used to package  precious goods like wine, glass arts, china arts etc. Kraft paper is made of 100% pure natural wood pulp. Its features are good density of fiber, good toughness, good compression and tear resistance, surface is smooth suitable to printing. Used as outer liner, inner liner or middle liner of 3/5/7 ply corrugated cardboard. The levels of kraft paper are A, B, C, D. A/B/C level kraft paper can be used as liner.

Test liner is made by : mixing waste paper pulp, wheat pulp or straw pulp as bottom slurry and natural wood pulp as surface, it’s used to produce medium-low grade corrugated cartons.

White top liner is suitable for high definition printing packaging material . Its bottom slurry is waste paper pulp, surface slurry is bleached pulp. White liner as outer liner corrugated board’s surface is smooth shiny, it’s able to be varnished to achieve high definition printing effect just like offset printing.

High definition flexo printing corrugated carton with varnishing process