Flexible slabstock Polyether

It can be seen that moulded flexible PU foams using EO capped polyether polyols (block copolymers PO-EO with terminal poly[EO] block) represent only 22% of total worldwide consumption and that the majority of foams are flexible slabstock PU foams which use random copolyethers of PO-EO. It can therefore be concluded that the most important polyols for flexible PU foams production are in fact the random copolyethers PO-EO. 

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). 

The polyether polyols for flexible PU foams frequently have a distinct, unpleasant smell. In case of flexible slabstock foams where, in the centre of the PU bun, there are high temperatures (150-170 °C), an unpleasant odour appears during the foaming process which remains for a long time in the resulting PU foams. 

Not taking cyclic molecules into account, the general structures of industrial silicone surfactants for flexible slabstock foam production can be seen in Figure 2.13. The main building blocks of these materials are a PDMS backbone and attached polyethers based on ethylene oxide and propylene oxide addition products. The siloxane backbones can either be linear or branched and can have their polyether substituents attached in an either pendant or terminal location. These four general structures are outlined in Figure 2.13). 

Figure 6a and c show typical structures of silicone surfactants for the production of polyurethane foam, i.e., comb-like and branched siloxanes. Siloxanes that are modified with polyether groups are important surfactants for rigid, ester, or flexible slabstock foams. 

There are two main types of flexible foam slabstock polyester-based foams, used for technical and high elongation grade laminates or textiles and polyether-based foams used for upholstery, HR, and flame retardance. By varying the type of polyester or polyether, the length of the polyol chain, the structure and size of the hard segment, and the amount of blowing, the foam can be tailored to meet the required specifications. ... 

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). 

The PO homopolymers (MW of 3000) initiated by glycerol are some of the most popular polyols for flexible PO slabstock. This structure is one of the oldest structures of a polyether used for flexible PU foams. In essence these polyether triols are obtained by the anionic polymerisation of PO initiated by glycerol and catalysed by KOH. 

The random copolyether triols PO-EO, usually called heteropolyether polyols, with a MW of 3000-3600 daltons, are the most important polyether polyols for flexible PU slabstock foams, generally used in furniture industry. The worldwide consumption of flexible PU foams is presented in Figure 4.16. 

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). 

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. 

Bayer markets a dimethylpropane phosphonate-based FR called Levagard VP SP 51009 to enable rigid PU foam to meet fire regulations. Clariant offers liquid phosphorus polyols for the protection of polyether flexible and slabstock moulded automotive foams. Flexible PU is also commonly flame retarded in Europe with chlorinated phosphate esters. Borates have not shown... 

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... 

Slabstock flexible polyether foam is used mainly for furniture cushioning, mattresses and vehicular seating. The largest application of moulded flexible polyether foam is in automobile seating. 

Uses Surfactant for the production of standard flexible polyurethane slabstock foam based on polyether polyols... 

Uses Foam stabilizer in mfg. of flexible polyether PU slabstock and molded foam ... 

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