Polyurethane recycling

Polyurethane is pulverized to iacrease its bulk density, mixed with 30—80% of a thermoplastic mol ding material, gelled, and then granulated to give coated urethane foam particles 0.1 to 0.15 mm in size (48). The particle bulk density is three times that of the polyurethane, while the volume is 15% less. This material may be injection molded or extmsion molded into products (49). Other technologies for recycling polyurethanes have also been reported. 

Urethanes Technology 15, No.6, Dec. 1998/Jan. 1999, p.26-7 RECYCLING POLYURETHANES LOTS OF WAYS TO DO IT, NOT MUCH BEING DONE ... 

Yang, L. and Kooker, D., Cured polyester plastic compositions derived from recycled polyurethanes, US Patent 5 859 167 1999. 

A simple process for recycling polyurethanes has been developed by the Ford Motor Company. Can you suggest a way to accomplish this What products would you expect to obtain ... 

Research was conducted on the method of recycling polyurethane, formulation of recycled polyurethane-modified recycled polyester (RPUMRPE) and their mechanical and chemical resistance properties. 

This process can achieve a recovery of scrap foam into a polyol mixture, which can be used to produce polyurethane without the need for purification. This method requires low capital investment and is simple enough to cope with variations in the mix scrap foam. The resulting recycled polyol can be incorporated with polyisocyanate to produce recycled polyurethane which can be used to modify recycled polyester mortar made with either virgin or recycled resins. 

Recycled Polymer Mortar from Recycled Polyurethane and Polyster (RPUMRPE) [4]... 

In this work, polyurethane was made from recycled polyol obtained from rigid foam and polyisocyanate. The raw material for the polyester resin was recovered from scrap PET [5], then depolymerized using different amounts of ethylene, propylene glycol into glycolized monomer and oligomer. These glycolized products were reacted with maleic or terephthalic acid to obtained recycled polyester. The proportion of recycled polyurethane to recycled polyester was varied ranging from 1 1, 1 2, 1 2.5, and 0 1. The combined resins were then mixed with initiator,... 

This tensile strength was measured using dog bone specimens with a 1 in.xl in. (25 mm><25 mm) crosssection. The results of Table 1 show that RPUMRPE mortar exhibits an excellent tensile strength of about 1700 psi (11.72 MPa) after 7 days when the ratio (RPU RPE) ranges from 1 2 to 1 2.5. It can be seen that recycled polyurethane improves the tensile strength of the recycled polyester. 

Recycling within the section on Environmental Protection the report describes BASF s approach to recycling, and the example given is of selling solvent stripped from a waste stream. Elsewhere articles feature recycling polyurethane foams and hydrogen chloride. 

Table 3.33 Properties of products incorporating recycled polyurethane...

E. Weigand, Properties and Applications of Recycled Polyurethanes in J. Brandrup, M. Bittner, W. Michaeli, and G. Menges, eds.. Recycling and Recovery of Plastics, Hanser/Gardner, Cincinnati, 683-701 (1996). 

The Alliance for the Polynrethanes Indnstry operates a recycled polyurethane markets database that allows searches for either buyers or sellers of polyurethane. ... 

Alliance for the Polyurethane Industry, Recycled Polyurethane Markets Database, http // www.polyurethane.org/recycling/markets/markets search.asp. 

ICI Polyurethanes is working on development of a split-phase glycolysis chemical recycling technology for polyurethane, and plans to build a full-scale plant in Britain to recycle polyurethane foam from mattresses, furniture, and automotive seat cushioning. 

Other approaches to recycling polyurethane have focused on chopping up the flexible varieties and using them as filler in new polyurethane products. Rebonded seat foam materials have been studied for use in... 

A pilot plant was opened in the UK by ICI in 1998 to look at the feasibility of chemically recycling polyurethane, their method being a process called split-phase glycolysis [8]. Like hydrolysis, the method is complicated by the presence of by-products. Commercial depolymerisation units using the glycolysis of polyurethanes operate in Germany, Austria and Denmark [4]. The requirement for separation can be avoided in this case by further chemical reactions. The basic chemistry involved in these reactions is presented by Ehrig [9] for those who require further details. 

Borda J, Racz A and Zsuga M (2002) Recycled polyurethane elastomers a universal adhesive, J Adhesion Sci Technol 16 1225-1234. 

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