Rigid foam wastes glycolysis

The application of a glycolysis process with simultaneous deamination to the recovery of polyols from rigid PU and polyisocyanurate foam waste is described. Properties and applications of the polyols obtained are examined. GETZNER CHEMIE GMBH... 

A split phase glycolysis process for the recovery of polyols from PU foam waste is described. Applications of the polyols in the manufacture of flexible and rigid PU foams are examined, and the economics of the process are analysed. 2 refs. 

Aminolysis of rigid PU foam wastes takes place at higher reaction rates than the glycolysis reaction and at lower temperatures (160-170 °C instead of 190-210 °C) [31-33]. 

The technology for the chemical recovery of rigid PU foam and isocyanuric foam wastes (a variant) by glycolysis processes involves the following main steps ... 

Figure 20.2 Technological scheme for recovery of rigid PU foam wastes by glycolysis process (variant) 1 Mills for PU scrap 2 Storage of ground rigid PU foam 3 Screw for powdered materials 4 Glycolysis and alkoxylation reactor 5 Electrical induction heaters 6 Filter press 7 Storage tank for the recovered polyol 8 Gear or screw (or...

The glycolysis reaction consists of the stepwise addition of finely ground rigid PU foam wastes, to DEG with a continuous screw feeder, in the presence of a catalyst (NaOH,... 

A schematic diagram of the chemical recovery of rigid PU foam wastes by glycolysis is presented in Figure 20.3. Similar technological flows would be used for aminolysis or aminolysis - alkoxylation processes. 

Chemical recovery processes by PU polymer breakdown through hydrolysis, glycolysis and aminolysis processes are extremely important because by using chemical reactions, the PU wastes are chemically transformed into new products which can possibly be used in the fabrication process of new PU. PU wastes are important raw materials for new polyols destined to become rigid and flexible foams. 

Glycolysis of flexible PU foams is also possible. At a ratio of PU waste DEG of 1-1.5 1, two layers are formed (the superior layer being rich in polyether), but at a higher ratio of 2-4 1 a homogeneous polyol mixture results, with an hydroxyl number of 360-390 mg KOH/g, which was used successfully in rigid PU foam fabrication [35]. 

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