additives
1. Substances added in small proportions to
products to improve their performance, or to
enhance their attractiveness or value. Additives
are also used to prevent bacterial action, drying,
staling, as well as to inhibit corrosion,
oxidation, decomposition, etc. 2. All of the
nonfibrous raw materials used in making paper.
They may be added at any point during the
papermaking process or after the paper has been
manufactured. Treatment of the entire sheet
(internal treatment) entails mixing the additives
with the paper pulp, in which case they are known
as wet-end additives. If only the surface of the
sheet is to be treated, the additives are applied
directly to the surface of the paper, and are
known as external additives. Paper additives are
used to color and size paper, control pH, improve
physical properties, and increase wet strength.
They are also used as defoamers, dispersants,
plasticizers, preservatives, retention aids, and
the like. (58 , 98 )
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