Recycling reactors for flexible PU foam residues


H&S technology of flexible PU foam recycling is based on optimized acidolysis method where PU residues are being dissolved in a mixture of carboxylic acids and basic polyol. In comparison to previous conversion methods, polyols generated by H&S technology have good reactivity and contain the number of primary aromatic amines (methylene and toluene diamine) below the legal requirements. Primary aromatic amines are hazardous and not acceptable in bedding and upholstery foams.

Process sequence and duration

Raw materials required for the process

  • Flexible PU foam residues
  • Basic polyether polyol for flexible foam
  • Carboxylic acids
  • Catalyst


Recovered polyol can substitute 20% and more of conventional polyol for production of bedding and furniture PU foam higher percentage for technical foams without any influence on the physical and mechanical properties of the PU foam.

Properties of the conventional PU foam produced with 20% recovered polyol produced on a continuous slabstock line (example):

Foam density 23 kg/m³

  Master sample (foam without recovered polyol) Foam with 20% recovered polyol
Resilience, %: 42,6 44,3
Hardness, [N]: 148,75 146,68
Support factor: 2,2 2,3
Compression set (50%): 2,3 2,4
Tensile strength, [kPa]: 156 152
Elongation at break, %: 241 238

Foam density 40 kg/m³

  Master sample (foam without recovered polyol) Foam with 20% recovered polyol
Resilience, %: 47,2 48,7
Hardness, [N]: 167,30 165,46
Support factor: 2,3 2,2
Compression set (50%): 1,88 1,91
Tensile strength, [kPa]: 158 157
Elongation at break, %: 214 214

The costs to manufacture recoverd polyol are 25-30% percent lower than the market price of the original basic polyether polyol.

Mattress produced out of conventional PU foam with 20% recycled polyol.

Repeatable recycling of the flexible PU foam

The process based on H&S technology enables to convert slabstock foam residues into polyol for at least 20 cycles without considerable influence on the chemical and mechanical properties of the recycled polyol and resulted PU foam.

Reactor and peripheral equipment (Core unit)


1. Reaktor
2. Activation tank
3. Feeding system for PU residues
4. Cooling tank

Flexible foam reactors can be supplied with batch capacity from 1t to 5t.