Pulp (massa)

Pulp is an intermediate product made of wood, and is most commonly used as raw material for paper. The properties of pulp depend on the species of tree and the manufacturing method used. The properties of paper may be modified by modifying the pulp used.

Mechanical, or groundwood pulp is manufactured mechanically, which means that the wood is ground so as to separate the fibres from each other.

Chemical pulp is manufactured through separating the fibres by boiling wood chips and chemicals together.

Mechanical and refiner mechanical pulp are made by grinding.

Chemithermomechanical pulp (CTMP) or chemi- mechanical refiner pulp is so-called semi-chemical pulp: the chips are first treated by chemicals, after which the pulp is manufactured mechanically, in the case of CTMP by grinding.

Wood-free pulp or paper is a product whose raw material does not include mechanical pulp, while wood-containing pulp or paper does include it.

Reinforcement pulp is made of softwood. Its purpose is to add body to the paper; it gives the paper strength, which is needed when it is used for printing, for example.

Special pulp is used for the manufacturing of other products besides conventional paper, such as textiles. Fluff pulp is used in diapers and sanitary towels. Kraft pulp is unbleached sulphate pulp. Market pulp is any pulp that the company does not use in its domestic mills and that it sells on the market or transports to its mills in other countries.