Lumber, Plywood, and Other Wood Products - Carpenter's and Builder's Math, Plans, and Specifications - page 80

Masonite, Celotex, Insulite, and Beaver board or, in the instance
of particleboards, by the kind of particle used, such as flakeboard,
chipboard, or oriented strand board (OSB).
These panel materials are all reconstituted wood (or some other
lignocellulose like bagasse) in that the wood is first reduced to small
fractions and then put back together by special forms of manufacture
into panels of relatively large size and moderate thickness. These
board or panel materials in final form retain some of the properties
of the original wood, but, because of the manufacturing methods,
gain new and different properties from those of the wood. Because
they are manufactured, they can be and are tailored to satisfy a use,
need, or group of needs.
Speaking in general terms, the wood-base panel materials are
manufactured by the following methods:
Changing wood substance, essentially to fibers and then inter-
felting them together again into the panel material classed as
building fiberboard.
Strictly mechanical means of cutting or breaking wood into
small discrete particles and then, with a synthetic resin adhe-
sive or other suitable binder, bonding them together again in
the presence of heat and pressure. These latter products are
appropriately called particleboards .
Building fiberboards, then, are made essentially of fiberlike com-
ponents of wood that are interfelted together in the reconstitution
and are characterized by a bond produced by that interfelting. They
are frequently classified as fibrous-felted board products. At certain
densities under controlled conditions of hot pressing, rebonding of
the lignin effects a further bond in the panel product produced. Bind-
ing agents and other materials may be added during manufacture to
increase strength, increase resistance to fire, moisture, or decay, or to
improve some other property. Among the materials added are rosin,
alum, asphalt, paraffin, synthetic and natural resins, preservative
and fire-resistant chemicals, and drying oils.
Particleboards are manufactured from small components of
wood that are glued together with a thermosetting synthetic resin
or equivalent binder. Wax sizing is added to all commercially pro-
duced particleboard to improve water resistance. Other additives
may be introduced during manufacture to improve some property
or provide added resistance to fire, insects such as termites, or decay.
Particleboard is among the newest of the wood-base panel materials.