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1. Production and Quality
of Paper

2. Introduction and History of Paper
• Paper is a thin sheet material produced by mechanically or chemically
processing the cellulose fibers derived from plant or plant products.
• They were developed in China, Egypt in earlier days and it is presumed that
Nepal adopted paper making in the Lichhavi dynasty.
• Papers are used for a variety of purpose such as packaging, writing, printing,
as tissue, etc.
• The papers extracted from Allo, Lokta and Argeli are used as Nepali Kagaj.
• China is the top most country in the world in paper production.

3. Pulp and Pulping
• Pulp is a commercial cellulose-derived fibrous material obtained from plant
or plant products like bamboo, wood, etc.
• It is used for the industrial production of paper and is the most important
raw material for the production of paper.
• Other raw materials include sizing elements, fillers, coloring agents, etc.
• The disintegration of long and bulky fibrous materials into individual or
small fibers is called pulping.
• The main objective of pulping is to separate the fibers from the material and
remove the lignin content from the wood mass.

4. Stages in Production of Paper
1. Timbering: Timbers are obtained from the matured trees which can be used
for the production of paper.
2. De-barking: It is the process of removing the bark of the trees from the
log by using knife, axe or hydraulic brakers.
3. Chipping process: The stripped timbers are chipped into small pieces by
using knives and the chips are stored in huge bins.
4. Pulping: It is the process of producing pulp from fibers. One of the various
methods of pulping is applied as per the need and feasibility.
5. Blend chest: Chemicals are added to obtain the desired features of paper.

5. Various Methods of Pulping
i.) Mechanical Pulping: It involves the grinding of raw materials against
abrasive surface to defiber the raw material however, there is no dissolution of
the lignin.
ii.) Chemical Pulping: The cellulose fibers are separated from the raw
materials by dissolving all non-cellulosic components in cooking liquor at
sufficiently high temperature and pressure. Kraft process is one of its type
where Na2S and NaOH are used as digestors.
iii.) Chemo-mechanical Pulping: It involves a chemical pre-treatment of the
raw material before processing the mechanical treatment to produce fibers.

6. Flowsheet Diagram of Paper Production

7. Quality of Paper
1. Weight: The weight of paper required varies according to their purpose.
2. Appearance: Factors such as brightness, whiteness and shape differ it.
3. Surface: Smoothness or roughness of paper depends on the finishing.
4. Opacity: It is the ability of a paper to mask the ink on the other side.
5. Size: Papers are of various dimensions such as A0, A1, A2, A3, A4, etc.
which are produced as per the requirement.
6. Longevity: It depends upon the composition of the paper.