Deutsch | English
Nowadays more than ever wood counts among the materials used
for manifold purposes. It is highly estimated because of its
many positive characteristics, such as
a whole variety of treatment, its ratio of strength to weight,
good thermal insulation and acoustic qualities and finally
its beauty – wood has become an absolutely essential
material. Apart from these and other positive features wood
has, compared with other materials, one disadvantage. Because
of its high hygroscopicity it is due to processes of shrinking
and swelling which consequently lead to interstices.
Therefore optimizing the stability of dimensions of wood by
various physical and chemical methods is one of the priorities
of international wood research. So far more than 25 methods
of improving the stability of dimensions of wood have been
Only few of them are applied in production, though.
Structure of the tests
The goal of a research project – Prime Wood GmbH Swiss
- was the improvement of the stability of dimensions of a
beech floor by using various resins which we were offered
by partners in industry. For impregnation we chose impregnation
by vacuum in various cycles optimized in several pre-tests.
The hardening of the resin was achieved by heat. In order
to carry out realistic research impregnated lamellas were
glued to a floor topping with glue for parquet floors. One
floor was – apart from the refinement – additionally
sealed with a water-based system. These test floors were exposed
to various climates, winter and summer conditions symbolically
simulated. While being put to strain, the floors were regularly
measured and the changes of the interstices taken down in
lists. Furthermore, surface standards, such as resistance
to scratching and abrasion were tested.
from a probe
The results reveal a stability of the dimensions of up to
80 % depending on the treatability process and PRIMOL MA and
PRIMOL H used.
With reference to the density of the beech wood an increase
in weight of up to 56% was achieved. The microscopic tests
prove a significant absorption of the resin into the cell
wall. The resin in the lumen which basically hardly adds to
improvement, was partly removed in a final vacuum state at
the end of the impregnation. The idea is to reduce the water
content and possibly the size of the molecules. The results
have also proved significantly better standards of scratching
and abrasion. Tests will be carried out to obtain results
for exposure to various weather conditions, as well as mycological
tests in our own laboratory.
The equipment for the impregnation consists of a vacuum pressure
tube having a vacuum range between -0.8 up to 6 bar. It´s
more or less the same the wood preservation industry has been
using for a long time.