Reactors and know-how for recycling of rigid / semi-rigid PU foam residues

Industrial waste from rigid and/or semi-rigid PU foams can be used in an efficient way for the production of recycling polyols which can be used for the manufacturing of rigid / semi-rigid PUs (sandwich and insulating panels, spray foam, shoe soles etc.).

The process developed by PU Engineering is based on reaction between glykols and the urethan chain ( Glycolysis ).


The recycling process

PU waste should be clean from impurities like paper and metal scraps. Impurities such as PE or PP do not disturb the process.

In a reactor with a volume of 200 dm3 (laboratory installation) up to 10 m3 (fully automatic industrial plant) the raw materials are charged: – glykols, catalysts, additives and rigid PU foam waste. The duration of the chemical process is about 10 hours.

No primary aromatic amines such as toluene diamine (TDA) and methylene diamine (MDA) that are classified as carcinogenic are present.

Up to 60% of PU waste can be included in the recycling polyol formulation, making the product extremely economical.


The productioncosts of the recycling polyol is about 40% lower than the price of the original polyol.


Properties of the recycling polyol based on rigid PU foam wastes:


The hydroxyl number of the recycled polyol can be controlled and fixed at a certain value and any change from Iso-Index is not necessary.


The properties of the PU panels produced with 40 % recycling polyol were compared with the properties of PU panels made with original materials. The comparative data is presented in the following table:


All parameters are in perfectly agreement.


The produced rigid PU foams show comparable properties such as traditional PU rigid foam using up to 40% recycling polyol.


Recycling reactors for rigid PU foam

  • Planning, construction and installation of an industrial (or pilot) installation for the recycling of rigid/semi-rigid PU foam wastes.
  • Transfer of know-how for the recycling of PU foam to recycling polyols suitable for the production of rigid/semi-rigid PU foam
  • Training for the realization of the technology on a laboratory scale.
  • Training on chemical methods for analyzing recycling polyols
  • Training for working with the industrial reactor’s software.
  • Training on the maintenance of the equipment
  • Accompanying the production from our engineers to the full implementation