During cardboard production, several layers of paper with different thicknesses and compositions are couched (pressed) together – without the use of glues. Board production is similar to paper production.
In the first production step, recovered paper and pulp are prepared for use in the manufacture. The pulp is separated into its component parts (fibres) in the waste paper treatment plant and macerated or broken up into a mixed pulp for production.
During the treatment process, the material is also freed from foreign bodies and polluting agents; subsequently, the printing inks still present on the recovered paper are removed in a de-inking process.
A basic principle of the treatment is to ensure that the mixture contains both recycled materials and new, unused fresh fibres, as the paper fibres become shorter with every new treatment process and thus lose their tear resistance and strength. This loss of strength not only has an impact on the cardboard’s quality but also leads to tearing of the cardboard sheets on the board machine.