Plastics have become the ubiquitous workhorse material of the modern economy – combining unrivalled functional properties with low cost. … Today nearly everyone, everywhere, every day comes into contact with plastics – especially plastic packaging, … While delivering many benefits, the current plastics economy has drawbacks that are becoming more apparent by the day. After a short first-use cycle, 95% of plastic packaging material value, or $80–120 billion annually, is lost to the economy.
The New Plastics Economy - Rethinking the future of plastics, World Economic Forum, 2016
Just in Denmark, between 300 and 400 tons of plastic ends up as waste every year. Around 85% of this mass is comprised of the 6 most common types of plastics,
- Polyethylene-terephthalate (PET)
- High-density polyethylene (HDPE)
- Polyvinyl chloride (PVC)
- Low-density polyethylene (LDPE)
- Polypropylene (PP)
- Polystyrene (PS)
while the rest consists of more technical (and expensive) plastics such as nylon (PA) and plexiglass (PMMA), and yet a smaller portion are thermosets.
Plastic can be divided into two major groups of materials, namely thermoplastic and thermosetting plastics. Thermoplastic materials are mouldable when heated, and are therefore relatively easy to recycle. Thermoset materials such as epoxy are cured by a chemical reaction and are therefore very difficult to recycle.
When recycling plastics, i.e. thermoplastics, it is crucial to separate different plastic types, as they have different melting temperatures and properties (cf. Precious Plastic, 2017). Therefore an efficient sorting system is needed, to avoid mixing plastic and ruining the recycled product.
Flexible Plastics Sorting
IHP Systems is developing an innovative, flexible plastics sorting machine – capable of sorting plastics by type and colour – even black plastic items can be sorted by type. The plastic items can be sorted into multiple fractions in one pass.
In order to achieve flexible plastics sorting, the IHP Systems plastic sorting machine utilizes the latest innovations in:
- Chemical Imaging – using spectral cameras to measure chemical spectra on-line.
- Computer Vision – detecting objects and analysing colour in order to sort plastics by colour.
- Machine Learning – classifying chemical spectra in order to sort plastics by type.