Most materials used for packaging are paper /card based. Card and paper are made from wood pulp and waste paper. When paper is examined through a microscope the fibres that form the material can be seen. The fibres are made from cellulose which is extracted from the wood pulp and recycled waste paper.
Wood pulp is the raw material and this comes from both coniferous and deciduous trees. Other chemicals are added until the correct texture / thickness is reached.
STAGES OF PAPER MANUFACTURE
A tree is cut down and the trunk is fed into a chipping machine where it is cut into very small pieces.
The wood chips are boiled in water to form a thick wood pulp
Chemicals / ingredients such as starch and bonding agents are added. The pulp is poured over a fine mesh and the water escapes leaving the cellulose fibres behind. This forms the paper.
Paper based materials such as cardboard are thick because they are made up of several layers of pulp. If greater even thickness is needed this is achieved by gluing layers of card together in a process called laminating.