Rigid foam wastes

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. 

Extrinsic detectors, 22 180 Extrinsic fiber-optic sensors, 11 148 Extrinsic photoconductors, 19 138 Extrinsic semiconductors, 22 236-237 Extrinsic wastes, 10 68 Extruded food packaging, 18 45 Extruded lead-copper alloys, 14 776 Extruded lead-tellurium alloys, 14 778 Extruded rigid foam, 23 404-405 Extruders... 

The characteristics for a recycled polyol presented in Table 20.1 have a large range of values due to the fact that the qualities of the rigid PU wastes used are not consistent (the rigid PU foam wastes are made in various densities, various formulations, some foams are degraded and so on). 

Rigid Polyols by Aminolysis of Rigid PU Foam Wastes [31-36,40,41]... 

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]. 

An interesting aminolysis process based on the reaction of ground polyether-based rigid PU foam wastes with an alkanolamine, in the presence of an alkaly hydroxyde as catalyst was developed [36, 40, 41], The ratio between PU waste and alkanolamine could be around 15 1 to 50 1 (one cubic meter of foam can be chemically destroyed by one litre of alkanolamine) [34, 41]. 

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. 

There is no single method for treating polymethane (PUR) waste, due to the different quantities, qualities, mixes, and cleanliness. It is estimated that some 125,000 t of RIM polyurethane is used worldwide, 85% in automotive parts, mainly in bumper fascias. Current technologies for physical recycling of PURs are mainly directed towards flexible and rigid foams, but systems have also been developed for recycling reinforced reaction injection molded (RRIM) PURs, on the... 

The presence of polymers in some systems can cause difficult problems where foam stability is not desirable. Such is particularly the case in waste treatment facihties, where the presence of proteins can cause extreme problems. If polyvalent ions such as Ca and are present, the problem is exacerbated still more. Proteins will bond strongly with such ions and form an essentially cross-finked surface film so rigid that it may approach the strength of a solid foam. Obviously, such a situation will be detrimental to the overall treatment process. In other situations, such as breads and other baked products, the formation of rigid foam walls can be particularly advantageous. 

Rigid PUR foam wastes were simultaneously aminolyzed with NH, ethylene diamine, diethylene triamine, hexamethylenediamine, or ethanolamine and alkoxylated by ethylene oxide, propylene oxide, butylene oxide, phenyl glycidyl ether, or styrene oxide optionally in the presence of a hydroxyl containing tert-amine (dimethyl ethanol... 

Polyurethane materials are extremely versatile in that it is possible to produce a large variety of structures which range in properties from linear and flexible to crosslinked and rigid. The crosslinked PURs are thermosets, which are insoluble and infusible and therefore cannot be reprocessed by extrusion without suffering extensive thermal degradation. At present, the main sources of recyclable waste are flexible PUR foams and automobile waste. Waste and scraps of these materials may consist of 15-25% by weight of total PUR foam production. 

Arcus gasification combuster is described and the principles upon which it works are explained. This combuster combines solid fuel gasification with the burning of the lean gases produced on a small capacity scale. The types of solid fuels which can be used are listed and these include segregated municipal waste and industrial waste such as rigid PU foam and plastics mixed with other materials. Uses of the gas produced are included. 

EarthShell also supplies materials for manufacture of thermoformed trays for fresh produce and meat, as well as disposable plates, bowls, and cups. In these products, polyester is used as a moisture-barrier over a rigid substrate made of a low-cost natural composite supplied by EarthShell and Apack AG, Germany. The EarthShell composite consists of cellulose from paper waste, starch from potato waste, ground limestone, and water. Apack dispenses with the limestone but adds a polymeric ingredient. Both composites are foamed and formed with special equipment in a process comparable to making waffles. 

C linkages and are hydrolytically unstable others do not contain a silicone-carbon bond and are stable. In general, higher-viscosity silicone copolymers are more efficient and wiU provide foams with finer cell structures. Surfactants are used at the 0.5% to 1% level in rigid urethane foams. With too little silicone foam, cell structure is large. Too much silicone does not affect the foam properties, but is wasteful. There is no known health hazard with the use of silicones (20). 

By chemical recovery of polyester [poly(ethylene terephthalate) (PET)] (Chapter 16) and PU wastes, by alcoholysis or by aminolysis (Chapter 20), new polyols are obtained that can be used in rigid PU foam fabrication. The vegetable oil polyols, obtained by chemical transformation of the double bonds in vegetable oils in various hydroxyl groups are a very attractive route to obtain polyols from renewable resources (Chapter 17). 

The reaction of polyethylene terephthalate) (PET) with diethanolamine, followed by propoxylation, gives liquid amidic polyols useful in rigid PU foam fabrication. This method is an efficient variant of PET waste chemical recovery (bottles, x-ray films, fibres and so on) [1]. 

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]. 

Nonwoven scrim Adhesive film/powder Chopped glass mat Adhesive film/powder Central core Adhesive film/powder Chopped glass mat Adhesive film/powder Polyurethane foam Decorative (face) fabric Typically polyester Hot melt Adds rigidity Hot melt Semi-rigid PU foam or resonated waste fibres Hot melt Adds rigidity Hot melt Present if the need for soft touch is required Typically polyester... 

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