1070-4272/03/7602-0310 $25.00 C 2003 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 76, No. 2, 2003, pp. 310!313. Translated from Zhurnal Prikladnoi Khimii, Vol. 76, No. 2, 2003,
Original Russian Text Copyright + 2003 by Plotnikova, Egorov, Khaliullin.
AND POLYMERIC MATERIALS
Flame Retardants for Wood, Based on Urea-Formaldehyde
Resin with Mineral Fillers
G. V. Plotnikova, A. N. Egorov, and A. K. Khaliullin
East-Siberian Institute, Ministry of Internal Affairs, Irkutsk, Russia
Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences, Irkutsk, Russia
Received March 29, 2001; in final form, November 2002
Abstract-The efficiency of flame retardants for wood, based on urea-formaldehyde resin with mineral
fillers is studied.
Wood is among the most widely used materials. Its
advantages are well known, as well as the major draw-
back, namely, high inflammability.
Wood and related materials are virtually equal
in fire points and specific heats of combustion .
Ignition of wood can occur both from open flame and
from hot objects and gases. Heat flow from the flame
initiates pyrolysis of wood materials.
Thermal decomposition of wood proceeds in two
stages. In the first stage (up to 280oC), endothermic
decomposition takes place, and the second stage is
divided into two substages, namely, combustion of
gases formed in thermal decomposition (flame burn-
ing) and combustion of charcoal formed (smoldering).
Raising the charcoal yield at the expense of com-
bustible gaseous decomposition products can con-
siderably reduce the inflammability of wood. This
can be achieved by decreasing the heating rate of the
material in order to form a layer of charcoal having
low thermal conductivity, directing pyrolysis toward
formation of incombustible gases, and providing con-
ditions for prevention of charcoal smoldering.
In practice, the methods to decrease the combus-
tibility of wood are as follows: applying flame-re-
tardant coating ensuring formation of a coke layer and
impregnation of wood and related materials or intro-
duction of dehydrating agents into their structure.
The most advanced method for flame retardation in
timber-based materials under conditions of a building
yard is to apply flame-retardant coatings. When af-
fected by a local short-term fire hazard source, flame-
retardant coatings hamper burning of wooden struc-
tures, facilitate fire extinguishing, and, in some cases,
prevent fire events.
Polymers demonstrating a tendency toward carbon-
ization are capable of retarding burning of wood. In
recent years, extensive studies of their application for
flame retardation has been carried out. For example, it
has been demonstrated that wood impregnated with
urea oligomers passes into the category of difficultly
inflammable materials . However, despite the ad-
vances in science and engineering in the field of wood
preservation, no efficient method reducing the inflam-
mability of wood, suitable for mass construction ap-
plication, has been developed. The drawbacks of the
existing methods are either the complexity of fire-
proofing treatment, or in short supply of materials, or
the resulting deterioration of mechanical and decora-
In this work, we studied the effect of the composi-
tion of urea-formaldehyde resin (UFR) filled with
natural minerals on the flame-retardant efficiency of
coatings on wooden structures.
As a binder for the coatings we used KF-Zh urea-
formaldehyde resin [GOST (State Standard) 142313
88] ensuring the desired mechanical and adhesion
characteristics. The formulations were filled with
finely crushed mica (phlogopite), mineral wool, basalt
fiber, and graphite. To reduce the combustibility, a
fire retardant (diammonium hydrogen phosphate) was
The formulations were prepared as follows. First,
the fire retardant was dissolved in the resin. Then