Component A is a hydroxyl-containing
liquid that reacts with component B to produce the polymeric base
of polyurethane foam. Its color varies from light-yellow to deep-brown,
and it consists of a blend of several chemical compounds such as
polyesters, emulsifiers, foaming agents, and stabilizers. Component
A is low-toxic, inexplosive, and must be stored in a dry ventilated
place at temperatures not lower than 0į—.
Component A tends to split
during storage and must be thoroughly agitated before use by tumbling
and rolling the drum for 5 or 10 minutes. Component A is transported
in metal drums (100L, 200L, 220L or 240L).
Component B is a polyisocyanate
blended from 50 to 60 per cent of diphenylmethane diisocyanate and
larger molecular weight polyisocyanate with a volume ratio of isocyanate
groups not lower than 30%.
It looks like a dark liquid
and has a characteristic smell. The blend is toxic (the MPC of its
vapors in the occupational air is 0.2 mg/m3) and fire hazardous
(flash point 175°—, ignition temperature 215 °—).
Component B (polyisocyanate)
easily reacts with water and atmospheric moisture, producing a sediment
of solid polymeric material that cannot be reprocessed. Therefore,
drums containing component B must be tightly sealed and never exposed
to water or atmospheric moisture.
On long storage, particularly
at temperatures below +100?—, polyisocyanate (PIR) can disengage
a dark-colored fine crystalline mass that substantially increases
the componentís dynamic viscosity. In such cases, PIR can be reprocessed
after a special treatment.
The only Russian manufacturer
able to produce PIR is ZAO Korund, which was down since mid-2002
till late 2004 for a number of reasons. The plant resumed the manufacture
of small quantities of isocyanate in the beginning of 2005 (initially,
for batching of spraying systems).
The overwhelming part of
component B used in our country comes from outside Russia. The main
PIR suppliers are Bayer, Elastogran (Germany), Huntsman (Netherlands),
and Dow Chemical (USA). Some isocyanate is also imported from Hungary,
Japan and, to a smaller extent, from Poland. Since the fall of 2003,
we have greater supplies of component B from China, where a new
Huntsman plant was launched. Dow and BASF are also rapidly building
similar facilities in China, which are expected to be commissioned
by the summer of 2006. This may put an end to the current shortage
of isocyanate and, consequently, stop the price hike.
There are simple reasons
why European and U.S. companies are building factories in China:
the good financial investment climate, the cheap manpower, and the
desire to move the hazardous production to remote countries. The
quality of isocyanate currently manufactured in China is not worse
that that produced in German or Spanish plants, but its price may
be somewhat lower. In Russia, Chinese-made PIR is sold ex storehouses
in Syzran (Samara Region).
For the period from June
to October 2004, the price for isocyanate has risen from RUR 65,000
to RUR 105,000. Price increasing factors have again been in place
since early June of 2005.
The 2004 price hike has
resulted in an extraordinary situation that could not have occurred
before, where the price of a foreign-made system bought directly
from Moscow offices of Dow, Huntsman, Elastogran, or Bayer does
not differ much from systems offered by domestic manufacturers of
Russian companies (except
Korund) only produce polyol. Domestic component A is manufactured
in Vladimir, Dzerzhinsk, Cheboksary, Perm, and Nizhnekamsk. As of
the early summer of 2005, the average price of a SYSTEM (A + B,
at a maximum ratio of 1/1.1) in Russia does not exceed RUR 90,000
(exclusive of tare cost). As of the early summer of 2006, the average
price of a SYSTEM (A + B, at a maximum ratio of 1/1.1) in Russia
does not exceed RUR 85,000 (exclusive of tare cost).
To have a guaranteed end product with claimed properties, one should
always purchase a SYSTEM of components (A + B) rather than try to
save and buy PIR and polyester separately. A small cost reduction
may result in an unsatisfactory quality of foamed plastic, although
it will be impossible to recover the damage from the component suppliers.
This is why we recommend
buying compositions directly from FEED MANUFACTURERS who warrant
that the produced polyester matches the specific batch of polyisocyanate
supplied in the system.
If you are buying the components
from resellers rather but not manufactures of component A, you are
both overpaying, being the source of the agentís profit, and running
a risk of getting unsolvable problems during processing. To avoid
such error, one should just keep in mind that the domestic feed
MANUFACTURERS are ONLY located in Vladimir, Cheboksary, Perm, Nizhnekamsk,
Below is the list of dedicated
polyol producers whose product quality has been appreciated by our
ZAO Uretan, OOO Vladipur, OOO Izolan in Vladimir;
ZAO Korund in Dzerzhinsk
OAO Himprom in Cheboksary
OOO Dekka in Perm
Besides, we have good relationships
with Russian representative offices and distributors of Bayer, Elastogran,
Huntsman, and Dow.
We have exhaustive information
on what, where and at what price you can buy. We know ALL Russian
manufacturers and traders of components. And we are ready to share
this information with you. We will help you choose the best feed
supplier to suit your specific objectives and location.
When choosing a PUF system,
the consumer should be primarily based on the required end product
density. For wall insulation, for instance, a density of 40 to 60
kg/m3 is sufficient. The advisable insulation density for roofs,
particularly if they are design for a certain load, is from 60 up
to 80 kg/m3. In addition, heat-insulated flat roofs may be then
coated with a layer (max. 10 mm) of damp-proof skin, whose density
may range from 120 to 200 kg/m3. For spraying onto an interior ceiling
surface, where mechanical load is virtually impossible, an end product
density of 40 or 50 kg/m3 will be sufficient.
Typically, the price of one metric ton of a PUF composition does
not depend on (or varies insignificantly from) the end density of
the foamed plastic.
In theory, a metric ton
of the system having a claimed density of 40kg/m3 is capable of
producing 25 cubic meters of polyurethane foam (1000/40=25). But
the actual PUF output volume is generally smaller. When sprayed,
some part of material always rebounds from the surface to which
it is being applied. Another type of errors that also results in
over-consumption of feed is related to spray drift. In addition,
the components consumption rate depends on the geometrical outline
of the surface to which insulation is applied. In multilayer spraying,
when PUF layers are applied over one another, the inner layer may
be crushed by the outer coating. Experienced workers can minimize
the spraying loss (or over-consumption) of feed, but it takes time
to acquire the necessary skill.
On average, the loss rate may be as high
as 20%. Therefore, the actual raw materials cost for 1 cubic meter
of sprayed PUF in case of a claimed composition density of 40 kg/m3
and a system price of RUR 90,000 per MT is: 90,000/25=3600 RUR,
which must be corrected for 20 per cent loss, i.e. RUR 3600?1.2
= RUR 4320
When the components are mixed, a fine
colloidal solution is produced in the mixing head. The exothermic
reactions result in the buildup of the viscosity and temperature
of the solution. When the temperature exceeds 25 to 28į—, the foaming
agent begins to evaporate heavily and the composite starts to rise,
which is recorded as the initiation time. The growing viscosity
of the system and the presence of a silicone foam stabilizer regulate
the gas bubbles. A further growth of the bubbles is induced by the
polyisocyanate-water reaction. This composite reaction produces
a three-dimensional polymeric structure. The time when an integral
polymeric structure begins to form is recorded as the gel time.
At this stage, the low-crosslinked polymeric system has a large
number of unconverted moieties. The further recorded polymerization
phases are the aftertack time (loss of tackiness on the foamed plastic
surface) and the rise time (the time when the foamed plastic stops
The mentioned processes
occur at the initial stage of rigid foam molding. The main variable
(i.e., the gel time) is chiefly determined by the amount of catalyst
mixed in. Other properties depend on the catalyst type and amount
and on the quality of the primary components. In terms of chemistry,
the thermal insulation hardening process lasts for a few hours after
the product is demolded. And it takes several more days for the
mechanical relaxation processes to be finished.
For manufacturers who
want to have a guaranteed production of high-performance foamed
plastic in low-pressure units, we recommend using systems that contain
polyether-based (light-colored) polyol, not the dark PIR. To obtain
quality foam, the system initiation time must not exceed 25 seconds
and, generally, should be as short as possible.
In order to avoid problems
(such as nonconforming polymerization), we recommend that you purchase
your components only from manufacturers located in Moscow, Vladimir,
Dzerzhinsk, Novocheboksarsk, Nizhnekamsk, Perm, or Togliatti. If
you buy the materials from subpurchasers, you both have to overpay
and cannot be sure about its quality.
The polyurethane foam
production largely depends on the quality and properties of the
feed. One should bear in mind that the material requirements become
even stricter in case of PUF pouring, since the producer has to
account for a variety of what may seem to be external and judgmental
factors whose effect is less significant when PU foam is sprayed.
NST experts can willingly
provide most detailed information concerning different makes of
component systems and recommend a reliable supplier in your region,
whose products will be thoroughly adapted to your conditions and