Corrugated fibreboard is a very popular material, being strong but lightweight and versatile enough for a variety of applications. The structure is made up of a few key elements, including:
- Liners - the flat sheet elements; and
- Fluting - the wavy element attached to one or more liners, by means of adhesive applied to the top of the flutes.
The liners typically come in different levels of thickness and paper quality:
- Kraft liners
Made with at least 70-80% virgin pulp fibre. These liners are very stiff and strong with a good finished surface, and
are considered the top material grade. Kraft liners have a natural brown colour that varies slightly, depending on the
fibres, the pulping process and the mill location.
- Test liners
A cheaper alternative with a higher recycled fibre content. Test liners are typically not as strong as Kraft liners.
While many types of corrugated packaging may look similar to the untrained eye, the elements used have a significant impact on its performance. The material is classified according to the number, quality and thickness of the liners and fluting used. The more layers used, the stronger the packaging will be.