The raw materials
The raw materials used in manufacturing paper may be divided into 4 broad groups : fibrous raw materials, which constitute the main and indispensable element for paper manufacture; sizing material , used to add impermeability to paper according to the end use; loading agents, used to impart specific requisites to paper destined especially for printing; colouring agents, used to correct the base paper and for the production of coloured paper.
Type | Essences | Process |
Coniferous or resinous trees | fir | commonly with bisulphite |
pine | commonly with sulphate | |
larch | commonly with bisulphite | |
cypress | commonly with sulphate | |
Leafy or broad leaved trees | poplar | with bisulphate, sulphate and soda |
beech | with bisulphate | |
chestnut | with bisulphate and soda | |
aspen | with bisulphate | |
birch | with bisulphate | |
eucalyptus | with sulphate | |
Graminaceous | wheat straw | with soda chlorate and monosulphate soda |
rice straw | with monosulphate soda | |
Annual plants | alfa | with soda and soda chlorate |
esparto | with soda and soda chlorate | |
cane | with bisulphate | |
compact cotton / tufts | bland alkaline treatment | |
combed cotton | bland alkaline treatment | |
cotone linters | with soda | |
hemp | with soda | |
linen | with soda |