Meaning of TDI
Toluene diisocyanate (TDI) is a chemical use
the production of polyurethanes, primarily for
flexible foam applications including furniture,
bedding and carpet underlay, as well as
packaging applications. TDI is also used in the
manufacture of coatings, sealants, adhesives
elastomers. In transportation applications, TD
helps produce lighter automobile parts, saving
weight, which leads to improvements in fuel
efficiency and thus energy conservation.
the production of polyurethanes, primarily for
flexible foam applications including furniture,
bedding and carpet underlay, as well as
packaging applications. TDI is also used in the
manufacture of coatings, sealants, adhesives
elastomers. In transportation applications, TD
helps produce lighter automobile parts, saving
weight, which leads to improvements in fuel
efficiency and thus energy conservation.
From a technical perspective, TDI is obtained
nitration of toluene. The hydrogenation of
dinitrotoluene is then obtained to produce
toluenediamine (TDA), which is in turn reacte
with phosgene to form TDI.
Diisocyanates are a family of chemical building
blocks mainly used to make polyurethane
products, such as rigid and flexible foams,
coatings, adhesives, sealants and elastomers.
blocks mainly used to make polyurethane
products, such as rigid and flexible foams,
coatings, adhesives, sealants and elastomers.
Many of the products we rely upon every day
safer and more comfortable through the use
polyurethanes made possible by diisocyanate.
In its chemical formula, two of the six possible isomers are
commercially important: 2,4-TDI (CAS:
584-84-9) and 2,6-TDI (CAS: 91-08-7). 2,4-TDI
is produced in the pure state, but TDI is often
marketed as 80/20 and 65/35 mixtures of the
2,4 and 2,6 isomers respectively. It is
produced on a large scale, accounting for
34.1% of the global isocyanate market in
2000, second only to MDI. Approximately
1.4 billion kilograms were produced in
2000.
commercially important: 2,4-TDI (CAS:
584-84-9) and 2,6-TDI (CAS: 91-08-7). 2,4-TDI
is produced in the pure state, but TDI is often
marketed as 80/20 and 65/35 mixtures of the
2,4 and 2,6 isomers respectively. It is
produced on a large scale, accounting for
34.1% of the global isocyanate market in
2000, second only to MDI. Approximately
1.4 billion kilograms were produced in
2000.
Polyurethane chemistry is complex, but the
basics are relatively easy to understand.
Polyurethanes are produced by combining
diisocyanates with polyols and other chemical
additives. Because a variety of diisocyanates
a wide range of polyols can be used to produce
polyurethane and the speed of the reaction can
be adjusted, a broad spectrum of materials can
be produced to meet specific application need.
basics are relatively easy to understand.
Polyurethanes are produced by combining
diisocyanates with polyols and other chemical
additives. Because a variety of diisocyanates
a wide range of polyols can be used to produce
polyurethane and the speed of the reaction can
be adjusted, a broad spectrum of materials can
be produced to meet specific application need.
Diisocyanates are important in the production
countless products, particularly in the
transportation and construction industries.
In use since the late 1940s, diisocyanates are
family of chemical building blocks mainly use
make polyurethane products, such as rigid an
flexible foams, coatings, adhesives, sealants
elastomers. Many of the products we rely up
every day are safer and more comfortable
through the use of polyurethanes made possible
through diisocyanates.
family of chemical building blocks mainly use
make polyurethane products, such as rigid an
flexible foams, coatings, adhesives, sealants
elastomers. Many of the products we rely up
every day are safer and more comfortable
through the use of polyurethanes made possible
through diisocyanates.
Polyurethane chemistry is complex, but the
basics are relatively easy to understand.
Polyurethanes are produced by combining
diisocyanates with polyols and other chemical
additives. Because a variety of diisocyanates
a wide range of polyols can be used to produce
polyurethane and the speed of the reaction can
be adjusted, a broad spectrum of materials can
be produced to meet specific application need.
Diisocyanates are important in the production
countless products, particularly in the
transportation and construction industries.
Diisocyanates used in polyurethane production
are divided into two types: aromatic
diisocyanates and aliphatic diisocyanates .
are divided into two types: aromatic
diisocyanates and aliphatic diisocyanates .
Let me explain the two types of diisocyanates briefly
Aromatic Diisocyanates
There are two primary aromatic diisocyanates name:
toluene diisocyanate (TDI) and
methylenediphenyl diisocyanate (MDI). TDI is
used primarily in the production of flexible foam
MDI, the second type of DII, comes in two for
Pure MDI and polymeric MDI (PMDI). Pure MDI
is used in the production of a variety of
polyurethane products like elastomers, sealan
adhesives and coatings. PMDI is a highly
versatile product used to produce a wide variety
of rigid, flexible, semi-rigid and polyisocyanur
and thermoset foams.
toluene diisocyanate (TDI) and
methylenediphenyl diisocyanate (MDI). TDI is
used primarily in the production of flexible foam
MDI, the second type of DII, comes in two for
Pure MDI and polymeric MDI (PMDI). Pure MDI
is used in the production of a variety of
polyurethane products like elastomers, sealan
adhesives and coatings. PMDI is a highly
versatile product used to produce a wide variety
of rigid, flexible, semi-rigid and polyisocyanur
and thermoset foams.
There are also less common aromatic
diisocyanates, such as p-phenylene diisocyanate
(PPDI) and naphthalene diisocyanate (NDI).
Methylenediphenyl diisocyanate (MDI) is a
chemical used in the production of polyurethane
for many applications. MDI is used primarily in
the production of rigid polyurethane foams used
for insulation for your home or refrigerator , and
many other uses. Insulation made with MDI can
help consumers save on their heating and
costs and conserve energy . Some additional
of MDI in polyurethanes include coatings,
adhesives, sealants, and elastomers found in
items such as paints, glues, and weather
resistant materials. It is also used to make many
types of footwear, sports and leisure products
and to a much lesser extent, some specialty
flexible foams. MDI can also be used as a bin
for wood and to produce mold cores for the
foundry industry.
chemical used in the production of polyurethane
for many applications. MDI is used primarily in
the production of rigid polyurethane foams used
for insulation for your home or refrigerator , and
many other uses. Insulation made with MDI can
help consumers save on their heating and
costs and conserve energy . Some additional
of MDI in polyurethanes include coatings,
adhesives, sealants, and elastomers found in
items such as paints, glues, and weather
resistant materials. It is also used to make many
types of footwear, sports and leisure products
and to a much lesser extent, some specialty
flexible foams. MDI can also be used as a bin
for wood and to produce mold cores for the
foundry industry.
From a technical perspective, MDI is obtained
from the condensation of aniline with
formaldehyde to produce methylene dianiline
(MDA), which is in turn reacted with phosgen
form MDI.
Meaning of Aliphatic Diisocyanates
Diisocyanates, including the specific subset of
diisocyanates called aliphatic diisocyanates ,
been used since the late 1940s and have been
extensively studied. Aliphatic diisocyanates, serves
as hexamethylene diisocyanate (HDI), methylene
dicyclohexyl diisocyanate or hydrogenated MDI
(HMDI) and isophorone diisocyanate (IPDI), are
often further reacted to form polyisocyanates
which act as building blocks to form color
polyurethane coatings and elastomers.
diisocyanates called aliphatic diisocyanates ,
been used since the late 1940s and have been
extensively studied. Aliphatic diisocyanates, serves
as hexamethylene diisocyanate (HDI), methylene
dicyclohexyl diisocyanate or hydrogenated MDI
(HMDI) and isophorone diisocyanate (IPDI), are
often further reacted to form polyisocyanates
which act as building blocks to form color
polyurethane coatings and elastomers.
Uses of TDI
Let us now closely examine the uses of TDI
The main use for
toluene di-
isocyanate (TDI),
accounting for
about 90% of
world demand, is
in flexible
polyurethane (PU) foam used in furniture,
mattresses and car seats. Other uses
include rigid foams and adhesives, paints,
concrete sealers, as a cross-linking agent for
nylon 6, and as an intermediate in PU
coatings and elastomers. The main form is
an 80:20 mix of the 2,4 and 2,6-isomers.
toluene di-
isocyanate (TDI),
accounting for
about 90% of
world demand, is
in flexible
polyurethane (PU) foam used in furniture,
mattresses and car seats. Other uses
include rigid foams and adhesives, paints,
concrete sealers, as a cross-linking agent for
nylon 6, and as an intermediate in PU
coatings and elastomers. The main form is
an 80:20 mix of the 2,4 and 2,6-isomers.
DEMAND/SUPPLY
The TDI market started to recover in 2006
after a long and low-priced market in 2005.
More than 225,000 tonnes/year of capacity
closed during 2005 in the US at Bayer,
Huntsman and Lyondell. Dow Chemical shut
its plant in Porto Marghera, Italy, in August
2006.
after a long and low-priced market in 2005.
More than 225,000 tonnes/year of capacity
closed during 2005 in the US at Bayer,
Huntsman and Lyondell. Dow Chemical shut
its plant in Porto Marghera, Italy, in August
2006.
Producers say supply in Europe was tight in
2007 and no change is expected in 2008.
Demand has been robust, with markets in
Eastern Europe and the Middle East also
performing well. Growth last year in Europe,
the Middle East and Africa was expected to
reach 4-5%. Buyers are less optimistic for
2008, citing concerns that reduced consumer
confidence will affect demand.
The Science of TDI
The main route is the nitration of toluene to
dinitrotoluene, followed by catalytic
hydrogenation to toluene diamine, which is
dissolved in an inert solvent and reacted
with phosgene to produce a crude TDI
solution.
dinitrotoluene, followed by catalytic
hydrogenation to toluene diamine, which is
dissolved in an inert solvent and reacted
with phosgene to produce a crude TDI
solution.
TDI can be produced directly from
dinitrotoluene by liquid-phase carbonylation
with o-dichlorobenzene, avoiding the use of
phosgene and the waste recovery problems
associated with hydrogen chloride. One-step
processes based on the reaction between
dinitrotoluene and carbon monoxide have
been developed but not commercialized.
Bayer has developed technology that carries
out phosgenation in the gas, rather than
liquid, phase, reducing solvents use by 80%,
energy by 40% and investment costs by 20%.
Producers are focusing development efforts
on reducing costs and increasing plant size.
Properties
Molar mass- 174.2 g/mol
Appearance -Colorless to pale
yellow liquid
yellow liquid
Odor -sharp, pungent
Density -1.214 g/cm 3,
liquid
liquid
Melting point -21.8 °C (71.2 °F;
294.9 K)
294.9 K)
Boiling point -251 °C (484 °F;
524 K)
524 K)
Solubility in water Reacts
Vapor pressure -0.01 mmHg
(25°C)
(25°C)
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