PURMOL® 3 ST - An effective means for the removal of water in Polyurethane systems
Polyurethane is created by the reaction of isocyanate with a polyol. This is an addition reaction, in which no side-products are formed:
The presence of water leads to the dimerisation of isocyanates releasing carbon dioxide gas:
The release of carbon dioxide gas is intentional in the production of Polyurethane foams, but is undesirable in most other Polyurethane applications. This is due to the formation of the gas bubbles that accompanies this.
If water traces are introduced through the residual moisture present in the fillers and pigments in the formulation, then it is recommended to work the PURMOL® 3 ST into the polyol component before the addition of the isocyanate. The viscosity of the formulation would otherwise increase drastically; premature hardening could take place or uncontrollable foaming could occur.
Addition of the isocyanate should be delayed for a period of two hours, in order to ensure a complete adsorption of the water.
In addition, PURMOL® 3 ST can remove water traces on the surface of the substrate that is to be coated and can thereby guarantee the formation of a homogenous polyurethane layer without the formation of bubbles.
Finally, this grade can be used in other application areas such as specialist plastic formulations, PURMOL® 3 ST can be used to adsorb other impurities, such as carbon dioxide, hydrogen chloride as well as water. It also may be used in the drying of pigments and organic solvents.
For more information about these and other products, please contact your local depot or dedicated Account Manager. Alternatively, you can contact us through the form below.