Containerboard grades and how to go lighter

Containerboard grades

In our strive to make eco-friendly, lightweight containerboard components, we have studied and compared the different paper grades available on the market. Here's our overview, developed from CEPI's market definitions.

Virgin-based containerboard components

The expression virgin-based or fresh fibre containerboard, has traditionally been used for kraftliner and semi-chemical fluting.

Kraft paper has traditionally been defined as “paper or paperboard whose fibre content has no less than 80% fibers obtained by the chemical sulfate or soda processes”. It is produced from fresh cellulose fibres, for example chemical pulp made from softwood and hardwood.

Semi-chemical fluting is divided into two subgrades, semi-chemical 1 and semi-chemical 2. Semi-chemical 1 is the strongest grade and generally contains more than 80% semi-chemical primary fibres. Using semi-chemical pulp generally leads to stronger components than when using recycled-based pulp.

Recycled-based containerboard components

Recycled-based containerboard components normally consist of recycled liner, also called testliner, and recycled fluting medium, in different grammages. 

Testliner is a predominantly recycled fibre-based paper, which can be classified from 1-4 depending on their burst index and SCT values. Testliner 1 is the strongest and testliner 4, is the weakest medium allowed to be called testliner. 

In The European list of corrugated base papers, recycled medium fluting is defined as grammages from 100 g/m² and up. Within this category there are four subgrades; Medium 2, Medium 1, Medium high performance 1 and Medium high performance 2. Medium high performance 2 is the strongest and Medium 2 is the weakest.

The list defines Lightweight recycled medium (LWM) as recycled fibre-based papers in grammages below 100 g/m².

Source: Containerboard Europe, European list of corrugated base papers.