Before working with this product, you must read and become familiar with the available information on its risks, proper use, and handling. Information is available in several forms, e.g., in particular in the currently valid safety data sheets and product labels. For further information contact your Covestro representative.
Product description
Desmodur® XP 2556 is a prepolymer containing ether groups and based on diphenylmethane-4,4'-diisocyanate with isomers. It is used both as a one-component moisture-reactive adhesive and in combination with polyols as a two-component system for the formulation of adhesive and coating materials.
Form supplied
Solvent-free, yellowish viscous liquid
Sampling
The ingress of moisture must be avoided.
Specification
| Property | Test Condition | Value | Unit | Standard |
|---|---|---|---|---|
| NCO content | 15,5 - 16,3 | % | MDI-01-01 | |
| Viscosity at 25 °C | 1,500 - 2,000 | mPa*s | MDI-01-02 |
Typical Values
| Property | Test Condition | Value | Unit | Standard |
|---|---|---|---|---|
| Density at 20 °C | 1,14 | g/cm3 | DIN 51 757 | |
| Vapor pressure at 20 °C | (MDI) | 16 | mbar | EG A4 |
| Flash point | approx. 217 | °C | DIN EN ISO 2719 |
Storage
Recommended storage temperature 10 - 30 °C.Remains stable for six months from delivery when stored in closed containers under the exclusion of moisture.
Processing
At temperatures below 0 °C, crystals of diphenylmethane-4,4´-diisocyanate can form in Desmodur® XP 2556. The product can be rehomogenized by carefully heating the entire contents of the container to max. 70 °C for as briefly as possible.Care must be taken during compounding, transfer, etc. to exclude moisture as even the slightest traces of moisture adversely affect storage stability. It must be ensured that the containers - including those that are empty - are kept sealed. Above all, contact with water must be prevented as it reacts with Desmodur® XP 2556 to form polyureas and carbon dioxide. During storage, sample withdrawal, transfer and processing of Desmodur® XP 2556, the ingress of water in any form (damp containers, aqueous solvents, moist air) must be prevented as otherwise the formation of carbon dioxide may result in a dangerous increase in pressure in the tanks and containers. Furthermore, the formation of polyureas in Desmodur® XP 2556 can cause solids to separate, leading to blockages and malfunctions of the filters, pumps and pipelines of the foaming unit.
Health and Safety Information
Disclaimer
Contact
Please use our contact form or contact us directly by sending an e-mail to technical-datasheets@cx.covestro.com .
