Manufacturing of TDI
Manufacturing of TDI
The second main ingredient used in the manufacture of flexible foam slabstock is a di-isocyanate. In most cases this is a toluene di-isocyanate, or TDO. TDI occurs in two different forms (isomers), depending on the position of the reactive isocyanate groups. As these isomers have a different reactivity, it is essential that the isomer ratio of the TDI is carefully controlled. The most commonly used TDI contains a mixture of the 2,4 and 2,6-isomers in the ratio 80/20, sometimes abbreviated to TDO-80 or T80.
TDI-80 is manufactured commercially from toluene. Toluene is first nitrated to give 2,4- and 2,6-dinitrololuene( again in the isomer ratio 80/20) This is then reduced to toluenediamine which is finally phosgenated to give TDI-80.
The chemistry of TDI manufacture
Toluene (Nitration) =
2-4dinitrotoluene + 2-6-dinitrotoluene (reduction) = 2-4-toluenediamine + 2-6-toluenediamine (Phogenation) =
2-4-toluene di-isocyanate + 2-6-toluene di-isocyanate
The second main ingredient used in the manufacture of flexible foam slabstock is a di-isocyanate. In most cases this is a toluene di-isocyanate, or TDO. TDI occurs in two different forms (isomers), depending on the position of the reactive isocyanate groups. As these isomers have a different reactivity, it is essential that the isomer ratio of the TDI is carefully controlled. The most commonly used TDI contains a mixture of the 2,4 and 2,6-isomers in the ratio 80/20, sometimes abbreviated to TDO-80 or T80.
TDI-80 is manufactured commercially from toluene. Toluene is first nitrated to give 2,4- and 2,6-dinitrololuene( again in the isomer ratio 80/20) This is then reduced to toluenediamine which is finally phosgenated to give TDI-80.
The chemistry of TDI manufacture
Toluene (Nitration) =
2-4dinitrotoluene + 2-6-dinitrotoluene (reduction) = 2-4-toluenediamine + 2-6-toluenediamine (Phogenation) =
2-4-toluene di-isocyanate + 2-6-toluene di-isocyanate
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1 comment:
Dear Sir,
it seems that you are a producer of pu slab. can you help me with this?
i am producing the density= 17.5 with this formulation:
p=100 (polymeric 43% mixed with conventional)
tdi= index=115
h2o=4.9
si=1.5
so=0.25
amine=0.18
methylene chloride=4
filler=15% of all
but i can not get a good hardness. that would be very kind of you to help me,
best regards,
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