Chemical pulp is a man-made fiber of cellulose which is obtained from plant material (95% from wood) and is further processed predominantly in the paper industry, white pulp being used to produce printing and writing paper and brown pulp being used to produce paperboard and packing paper.
Chemical pulp is subdivided into the following groups:
-mechanical pulp (MP, TMP, CTMP)
in each case fully bleached, semibleached or unbleached.
Cellulose raw materials include all cellulose-containing materials, such as wood, cotton, straw and other annual plants. Yield varies between 15 and 80% depending on the raw material and processing method used. During production, the cellulose fibers are separated from one another, either by pressure boiling (chemical pulping) or by mechanical comminution:
-alkaline pressure boiling = sulfate pulp
-acidic or neutral pressure boiling = a) sulfite pulp or b) semichemical pulp
-mechanical comminution = mechanical pulp (MP and TMP)
-CTMP is subjected initially to chemical/thermal pretreatment and is then mechanically comminuted, thereby assuming an intermediate position.
Pressure boiling is followed by multi-stage bleaching. Unbleached chemical pulp is brown.
Once dried, chemical pulp is sold commercially in sheets, pressed blocks or rolls.
A distinction is drawn between papermaking pulps and special pulps. Special pulps are individually produced for their particular field of use, the important factor generally being chemical purity. See also IMDG Code & US CFR.
- Commodity Name:
CELLULOSE (Chemical Pulp)