COMPETITON - What sets NATwood apart from other
Thermally Improved Wood
(Thermo wood, Stellac Wood, le Bois Rétifié, Plato)
Wood is exposed to a temperature of 180 - 230°C for 24 - 48
hours under the exclusion of
oxygen. Swelling and shrinking of thermally improved wood are reduced
and the attack of
micro organisms is impeded. The colour is clearly changed toward
dark brown to black. The
disadvantages are the smell of burning, diminished mechanical properties,
hardness and change of colour.
Wood is soaked with synthetic monomers. Afterwards these are hardened
by applying heat or ionising radiation. There is hardly any swelling
or shrinkage with polymer
wood. The attack of micro organisms is almost completely prevented.
The mechanical proper-
ties, above all the hardness of the surface, are greatly improved.
Polymer wood is more like
plastic than wood. Monomers can permanently escape.
Pressure-Impregnated Wood (CCA Procedure)
Wood is impregnated under pressure with an aqueous solution of various
salts (cuprous, chro-
mous and arsenous salts) and other specifically active substances.
The prime purpose of this
form of wood improvement is an increased resistance against decay.
The mechanical properties
of wood are not improved by pressure-impregnation. Although this
method is often compared
with the Natwood technology, it is very different in its use and
purpose. The only common fea-
tures of the products are a considerably improved resistance against
micro organisms and si-
milarities in manufacturing. The use of hazardous and toxic materials
have brought this tech-
nology into disrepute.