Pulp Varieties

Pulp Varieties

 

Mechanical Pulp

• Stone Groundwood pulp: mechanically grinds the wood into relatively short fibres. End-use: the resulting pulp is used mainly in newsprint and wood-containing papers, such as lightweight coated (LWC) and super-calendered papers.

• Thermo-mechanical pulp (TMP): the wood particles are softened by steam before entering a pressurised refiner. End-use: TMP has mainly the same end-uses as Stone Groundwood pulp.

Variants of the above two processes are also possible.


Semi-chemical pulp

• Semi-chemical pulp: produced in a similar way to TMP, but the wood particles are chemically treated before entering the refiner.
End-use: this pulp has properties suited to tissue manufacture. Some chemi-thermo mechanical pulp is used in printing and writing grades.


Chemical pulp

• Sulphite pulp: produced by cooking pre-cut wood chips in a pressure vessel in the presence of bisulphite liquor. The pulp may be either bleached or unbleached.
End-use: ranges from newsprint, printing and writing papers, to tissue and sanitary papers.

• Sulphate (or Kraft) pulp: pulp produced by cooking wood chips in pressure vessels in the presence of sodium hydroxide (soda) liquor. The pulp may be unbleached or bleached.
End-use: widespread uses - pulp used for graphic papers, tissue and carton board, wrappings, sack and bag papers, envelopes and other speciality papers.

 

De-inked pulp

• Pulp made from recovered paper from which inks and other contaminants have been removed.