Surfactants Flexible moulded

Machine runs for the MDI flexible moulded foam were conducted on a Krauss-Maffei, cylinder displacement series, high pressure machine. Fresh premixes, consisting of the appropriate polyols, water, crosslinker, surfactants and catalysts for each formulation were charged to the machine. Modified MDI was used throughout the entire study. All chemical temperatures were held at 25 °C 2 °C via the machine s internal temperature control units. Foam pours were made into an isothermally controlled heated aluminium mould maintained at 60 °C 2 °C. The mould was a typical physical property tool designed with... 

Figure 1.41 shows a variety of flexible moulded Dabco surfactants which can be utilised in TDI and/or MDI formulations. Using Figure 1.41, proper selection of the surfactant can be made, enabling polyurethane formulators to expand their processing latitude, cell openness, and bulk stability of the foam article in their critical formulations. 

Figure 1.41 Flexible Moulded Surfactant/Property Relationships...

Non-hydrolysable silicone surfactants (for Asian PU foam producers) are Dabco DC2583 and DCS 188, respectively reducing surface skin and producing open-cell foam at low mould temperatures, and producing fine even-cell structure and improved emulsification in flexible slabstock systems. 

Flexible polyether foams are most commonly produced by a one-shot process. In this procedure, diisocyanate, polyol, water, catalysts and surfactant are all mixed simultaneously. Commonly, the mixture is fed continuously into a moving trough wherein, after a few seconds, the foam begins to rise. After 1—2 minutes the foam reaches its maximum height it is then cut into blocks which are allowed to stand for several hours before being sliced into sheets of the required thickness. Alternatively, the mixture of reactants is fed into heated moulds to give foamed-in-place mouldings. 

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