Applications
DESMODUR VP.PU 1520 A/31 is a liquid, dark-brown polymeric isocyanate based on diphenylmethane-4,4'-diisocyanate with isomers and homologues of higher functionality.
Sampling
Moisture access should be prevented when taking product samples.
Specification
| Property | Test Condition | Value | Unit | Standard |
|---|---|---|---|---|
| Density at 20 °C | approx. 1,23 | g/cm3 | DIN 51757 | |
| NCO content | 29,5 - 31,5 | % by wt. | MDI-01-01 | |
| Coefficient of thermal expansion | 0,000659 | K^-1 | ||
| Viscosity at 25 °C * | 250 - 350 | mPa*s | MDI-01-02 | |
| Acidity | max. 500 | ppm HCI | MDI-01-03 | |
| Specific heat (cp) | approx. 1,51 | kJ/kgK |
Storage
Storage in original sealed Covestro containers.Recommended storage temperature: 10 – 30 °CProtect from moisture, heat and foreign material.Covestro represents that, for a period of 6 months following the day of shipment as stated in the respective delivery documents, the product will meet the values set forth in section "specification" above provided that the product is stored in full compliance with the storage conditions and is otherwise handled appropriately. The lapse of this period does not necessarily mean that the product no longer meets specifications. However, prior to using said product, Covestro recommends to test such a product if it still meets the specifications. Covestro does not make any representation regarding the product after the period and Covestro shall not be responsible or liable in any way for the product failing to meet specifications after the period.
Processing
DESMODUR VP.PU 1520 A/31 may undergo partial crystallization at temperatures below 0 °C. The product can, however, be brought back into the liquid state by heating the entire contents of the drum for a short time to a maximum of 70 °C, although this may lead to an increase in the solids content. Drums including empty ones should always be kept tightly sealed. The product should never be allowed to come into contact with water, which reacts with DESMODUR VP.PU 1520 A/31 to form polyureas and carbon dioxide. Contact with water in any form (damp drums, solvents containing water, moist air) must be prevented not only during storage, but also when removing material from drums and during processing. Failure to do so may lead to a dangerous build up of pressure in tanks and drums due to the generation of carbon dioxide. In addition, polyureas forming in DESMODUR VP.PU 1520 A/31 can cause solids to separate out, leading to blockages in the filters, pumps and pipelines of the processing equipment and resulting in production problems.
