Description
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. Many of the products we rely upon every day are safer and more comfortable through the use of polyurethanes made possible by 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 and 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 needs. Diisocyanates are important in the production of countless products, particularly in the transportation and construction industries.
There are two primary aromatic diisocyanates: toluene diisocyanate (TDI) and methylenediphenyl diisocyanate (MDI). There are two primary aromatic diisocyanates: toluene diisocyanate (TDI) and methylenediphenyl diisocyanate (MDI).
TDI is used primarily in the production of flexible foams. MDI is used in the production of a variety of polyurethane products like elastomers, sealants, adhesives and coatings.
TOLUENE DIISOCYANATE (TDI)
Applications: Flexible foams, polyurethane products like elastomers, sealants, adhesives and coatings
| PARAMETER | TEST METHOD | VALUE |
| Appearance | Visual | Clear Liq. |
| Purity (% by wt.) | H900.6500S | Min. 99.5 |
| Color (APHA) | H900.1700S | Max.25 |
| Hydrolyzable Chlorine (ppm by wt.) | H900.3500S | Max.60 |
| Total Acidity (ppm by wt.) | H900.0500S | Max.40 |
| Isomer ratio 2,4 TDI (%wt.) | H900.4100 | 80±1 |
| Isomer ratio 2,6 TDI (%wt.) | H900.4100 | 20±1 |
| Sp.gr at 25/4 °C | S690.3000 | 1.22±0.02 |
| NIC (ppm) | H900.5800 | Max.30 |
METHYLENEDIPHENYL DIISOCYANATE (MDI PURE)
Applications: Raw material for production of various kinds of polyurethans, Sponges, Adhesives Refrigerator parts
| PARAMETER | VALUE |
| Appearance | Dark Colored Liquid, or Crystals Musty Smell, Volatile |
| Melting Point | 42-44 °C min |
| Specific Gravity at 18 ⁰C | 1.18 |
| NCO | Min. 33.4 % wt |
| Isocyanate Equivalent Weight | Max. 125.8 |
| 2,4 MDI content | 1.7-2.3 % wt |
| Hydrochloric acid | Max. 30 ppm wt |
| Ortho- dichlorobenzene | Max. 20 ppm wt |
| Phenyl isocyanate | Max. 20 ppm wt |
| Color (APHA) | Max. 20 |
METHYLENEDIPHENYL DIISOCYANATE (MDI POLYMERIC)
Applications: Flexible Foams, Polyurethane plastics, Polyurethane Coatings, Elastomer, Rigid Foams, Urethane Sealants, Cast Elastomer, etc.
| PARAMETER | VALUE |
| Appearance | Dark Brown Liquid |
| Specific Gravity at 25 ⁰C | 1.2-1.25 |
| Hydrolysable Chloride | Max 0.2 % |
| NCO | 30-32 % |
| Viscosity at 25 ⁰C | 150-300 Cp |
