Waste reduction in polyurethanes manufacturing

Polyurethanes frequently can be recycled in various ways. Choosing the appropriate recycling method depends on numerous factors, such as the properties of the polyurethane, market demand, the intended application for the recycled material and logistics (costs for collection, transportation, storage etc.).

Options for recycling/recovery of polyurethane include:

  • Mechanical recycling
  • Chemical recycling
  • Feedstock recycling
  • Energy recovery

Center for the Polyurethanes Industry (CPI)

The Center for the Polyurethanes Industry (CPI) and their associated issue management group, Polyurethane Recycle and Recovery Council (PURRC), have published documents on these topics that are accessible via the American Chemistry Council (ACC) website.

  • Click here to view recycling information on the ACC Internet site.
  • Click here to view information about energy recovery from flexible and rigid polyurethane foams.
  • Click here to view a list of publications from ACC regarding pre- and post-consumer recycling of plastics.

Flexible foam recycling/recovery

The methods below highlight some of the ways that polyurethane flexible foam can be recycled/recovered.

Rebonding (mechanical recycling): Flexible foam particles such as industrial scrap can be molded and held together with a binder to form a product. Applications include carpet padding, flooring, athletic mats, cushioning, packaging and acoustical materials.

Regrinding (mechanical recycling): Flexible foam and other types of polyurethane manufacturing scrap can be ground into a powder and mixed with polyol, thereby forming new polyurethane foam products which are molded into seating materials, for example.

Glycolysis (chemical recycling): This process produces polyols by reacting flexible foam or other polyurethanes with diols at temperatures greater than 200 degrees C. It is more suitable for recycling manufacturing process scrap vs. post consumer waste. Glycolysis yields polyols which can replace up to 90% of the virgin polyols in flexible/semi-rigid foam applications.

Energy recovery: There is value in energy recovery when recycling is not technically or economically feasible, as polyurethane foam's net heating value ranges from approximately 25 to 30 MJoules/kilogram. Various combustion technologies can be used for flexible foam incineration with energy recovery.

Rigid foam recycling/reuse

The methods below highlight some of the ways that polyurethane rigid foam can be recycled / reused.

Particle reuse: Particles/powders obtained from grinding up manufacturing process scrap can be used as adsorbents for cleaning up liquid spills.

Adhesive pressing (mechanical recycling): This process involves coating rigid foam particles from manufacturing foam block/panel scrap and other sources with binders such as polymeric MDI. This material can then be molded or pressed into boards by curing at elevated temperature and pressure. Typical applications include particle boards for flooring and housing/construction.

Glycolysis (chemical recycling): Similar to flexible foams, rigid foams can be recycled using glycolysis.

Energy recovery: Similar to flexible foams, energy can be recovered from rigid foam insulation.

Recycling options for Reaction Injection Molding (RIM)

Several options are possible for recycling polyurethane RIM parts, including regrinding, adhesive pressing, compression molding, injection molding, glycolysis and energy recovery.

Recycling of polyurethanes in mixed waste streams

Since polyurethanes and other plastics are frequently part of streams containing a variety of wastes, various feedstock recycling processes can be used to transform mixed plastics wastes into gaseous and liquid hydrocarbons for use in other processes. This includes feedstock recycling processes, pyrolysis, syngas generation via gasification and oil generation through hydrogenation.