Flexible slabstock foams continuous

The polyether triols are the most important class of polyether polyols and they are used in flexible PU foam fabrication. The majority of polyether triols used in flexible foams are copolymers of PO-EO. Random copolymers are used in continuous slabstock flexible foams and block copolymers (PO-EO), with terminal poly[EO] block, are used in moulded foams (hot moulding and cold cure moulding processes). 

This structure was used successfully for continuous slabstock flexible PU foams. The polyethers have a MW of 3000-3600 daltons (hydroxyl number of 46-56 mg KOH/g), a viscosity of 550-650 mPa-s, have practically only terminal secondary hydroxyl groups and contain around 10-12% EO internally distributed. 

PHD polyols are successfully used for high resilience flexible PU foams (made by the cold cure process), for continuous slabstock flexible PU foams and for elastomers obtained especially by reaction injection moulding (RIM) technology. 

PIPA polyols, in spite of some disadvantages (tendency to foam shrinkage, and scorching), are used successfully for continuous slabstock flexible PU foams and high resilience foams (cold cure moulding process). 

The polyether most used in practice for continuous free rise slabstock flexible PU foams are the triols, copolyethers PO-EO, containing around 10-15% EO randomly distributed (most used 10-12% EO), of MW in the range of 3000-3600 daltons (OH = 42-60 mg KOH/g). 

In this section the most important random copolyether PO-EO structures were presented. Considering the highest production volume, the random copolyethers PO-EO with a MW of 3000-3600 daltons are the most important polyether type produced worldwide, used in continuous flexible slabstock foams, with the highest volume of consumption (of around 78% from the total flexible foams). 

For continuous flexible PU slabstock production, the heteropolyether triols PO-EO are considered universal polyols used in conventional soft and supersoft flexible PU foams, covering a large range of densities (12-40 kg/m3) and load bearing properties. 

Flexible polyester foams are nearly always prepared by a one-shot process most commonly they are produced as slabstock by a continuous method exactly comparable to that described previously for polyether foams. A typical formulation might be as follows ... 

Polyether foams. "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. About 80% of such foam is produced in slabstock form in large blocks (with cross-sections up to about 12 m wide and 1.25 m high) and 20% is moulded. Commonly, in the production of slabstock the mixture is fed continuously into a moving trough... 

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