Recycling means the reuse of the waste materials in a production process for the original purpose or for other purposes excluding energy recovery. Reprocessing can be done using mechanical or chemical methods to reuse the wasted material. Mechanical reprocessing in the production for the original purpose is the best recycling solution.
The recycling of plastics is a difficult problem because of three main features:
1. A worldwide consumption of roughly 200 million tonnes for a turnover of about $700 billion,
2. A heterogeneous stream of very diversified and often non-miscible materials from commodities up to very expensive high-tech materials, including thermoplastics, thermosets, composites, foams, hybrids...
3. A wide scattering of end-of-life parts and goods of various forms and weights, from the carrier bags up to yachts, car bodies or plane wings.
It is estimated that in round figures, plastic wastes produced per year represent 50/60% of the produced plastic goods in the same year, that is to say around 100 million tonnes per annum.