Desmodur® CD-C

Desmodur CD-C is moisture-sensitive and should therefore always be stored in moisture-tight containers. Prolonged storage at temperatures in excess of 300C leads to a deterioration in quality as the product becomes increasingly cloudy due to the deposition of low solubility sediment (dimer formation). If the recommended storage temperature is exceeded for a long period (especially if the temperature of the product rises to above 500C), or if the recommended shelf life is excessed, a chemical reaction may take place. In addition to a reduction in the NCO content and an increase in viscosity, carbon dioxide in particular may be generated. The resultant increase in pressure may cause the container to swell or burst. Storage at below 150C results in crystallization. Desmodur CD-C should under no circumstances be stored in crystallized form as this will promote the formation of insoluble dimers and it will no longer be possible to melt the product completely. Delivered product should be spot–check for crystallization, and cooling to below 150C must be avoided. If Desmodur CD-C has been transported or stored below 150C for a short time, the material must be re-melted immediately at 60 - 700C. The melting point and the time required for this should not be exceeded as this also significantly promotes dimer formation. The entire container contents must be melted and homogenized before the container is immediately tightly resealed and its contents cooled down to the recommended storage temperature. There is no risk that quality will be affected should be product have crystallized briefly, but it can be expected that the shelf life will be reduced. The melted material should be used as soon as possible.