At the end of their service life, polyurethanes can be sent for reuse (for example, rebonding) or chemical recycling*, or can be incinerated for energy recovery. In many cases, polyurethanes can be just as valuable after they have served their intended purpose and are ready to be discarded.
Today, there are more options than ever for reuse of polyurethane scrap materials, with some no- or low-cast options available. For example, CPI is working with the Vehicle Recycling Program to promote the recycling of polyurethane car parts and several interested companies to investigate energy recovery methods for polyurethane foam. Of course, consideration must be given to national, regional and local requirements.
There are several mechanical recycling processes for polyurethanes currently in use:
- Regrinding industrial and post-consumer flexible polyurethane foam into powders to produce new foam.
- Flexible Foam Bonding yields a variety of padding products, including recovered pieces of flexible polyurethane foam used in products such as carpet underlay and athletic mats.
- Adhesive Pressing coats polyurethane granules with a binder and then cures them under heat and pressure to make contoured parts like automotive floor mats and tire covers.
- Compression Molding polyurethane granules under heat and pressure can produce rigid and 3-D parts, such as pump and motor housings.
Energy recovery processes are another key initiative in the polyurethanes industry to help reduce fossil fuel consumption. CPI conducts experiments and implements practices to convert post-consumer polyurethane waste into valuable energy. CPI has also provided ongoing support to the first community mattress-recycling program in the United States, and developed the Recycled Polyurethane Markets Database of contacts and companies who recycle polyurethane and polyurethane raw materials in the United States and Canada.
Advanced Chemical Recycling processes include:
- Glycolysis produces polyols, a key polyurethane raw material, from process and post-consumer polyurethane scrap by reacting polyurethanes with diols at high temperatures.
- Hydrolysis, a reaction of polyurethane with water, can produce polyols and amine intermediates from polyurethane process and post-consumer scrap. When recovered, the polyols can be used as effective fuels and the intermediates can be re-used to produce other polyurethane components.
- Pyrolysis uses a heated, oxygen-free environment to break down polyurethane and plastics into gas and oil.
- Hydrogenation takes pyrolysis one step further to produce pure gases and oils through a combination of heat, pressure and hydrogen. The purity of gases and oils derived from pyrolysis and hydrogenation, and the associated costs to produce functional finished products are important issues to be resolved.
- When disposed of in landfills, polyurethane-based products usually so not show any adverse effects on landfill processes, such as degradation or unwanted materials leaching.