Types of Paper, Paper Weights & GSM
Despite Kraft and Test liners being so popular, there are in fact a number of other options.
The available paper grades for outer and inner liners when manufacturing cardboard are as follows:
- KRAFT (K): Virgin Kraft paper
- TEST 2 (T2): Partly recycled liner paper
- TEST 3 (T): Fully recycled liner
- CHIP (C): Waste based liners
- FULLY BLEACHED WHITE (BW): Fully bleached Kraft liner
- WHITE TOP (WT): White coated recycled liner
- MOTTLED KRAFT (MK): Mottled white Kraft
- OYSTER (OY): Mottled test liner
- SEMI CHEM (SC): Virgin fibres using neutral sulphite semi-chemical process
- WASTE BASED (WB) 100% recycled fibres
Some of the most common paperweights that are used for corrugated material include:
- 125 GSM
- 150 GSM
- 200 GSM
- 300 GSM
Besides the varying paper weights and types, the type (and number) of fluting must also be considered.
At a basic level, a corrugated board is made up of the two liners, plus the single fluting. This is known as a ‘single wall’ board.
However, adding up an additional fluting section alongside an additional liner is known as ‘double wall’ or ‘double walled’ cardboard.
This effectively adds extra rigidity and strength, making it suitable for packing heavier products or adding additional protection for items that may more delicate or expensive.
Finally, if the items you are shipping are particularly heavy or large (for example automotive parts, industrial equipment etc.) then a ‘triple walled’ grade can also be used. As the name suggests, this adds another section of fluting and additional liner.Also referred to as Tri-Wall (which is the brand name of the manufacturers too), you can see a basic diagram of this below.