Unpigmented (Natural) HDPE
Natural material has the highest value as a recycled stream since it has the widest variety of end-use applications. It can be easily identified for food-grade end use applications.
Translucent and opaque colors
HDPE is commonly colored so volumes and markets exist for colored material and it is economical to process.
Optical brighteners are not removed in the recycling process and can create an unacceptable fluorescence for next uses of recycled HDPE. It is difficult to identify material with this negative effect until extremely late in the recycling process where a great deal of added cost has been imparted into a material of low value due to the additive.
REQUIRES TEST RESULTS
Colors with an L value less than 40 or an average NIR reflectance less than or equal to 10 percent
Sortation testing for dark colors using Sort-B-02 will determine whether a dark colored item will be considered Preferred, Detrimental, or Renders Non-Recyclable.
There is no mechanical property inherent in dark HDPE that makes it unrecyclable. The problem lies in sorting and the physics behind polymer identification. NIR (near-infrared) sorting technology used in MRFs is not capable of identifying many dark colored polymers since the colorant absorbs NIR energy. There are dark shades that may be detected by NIR, and a HDPE label of a different color on a package might aid in detection by NIR. It is not feasible to use manual sorting to separate one dark polymer from another since they cannot be distinguished by sight.
Recent innovations in both black colorants and sortation technology have created the possibility of sortable black HDPE containers. NIR detectable dark/black color concentrates are now available in the marketplace. Companies that are considering such colorants and are unsure of their compatibility with recycling should ask their suppliers to provide APR test results. An item may meet APR Guidance for NIR optical sorting, but may still not be considered recyclable in communities that have chosen in the past to not collect black plastics.
Surveys of reclaimers have indicated that they are willing to purchase bales containing black items. However, it is always advisable to verify markets for new items.
It should be noted that dark colors used in oil bottles and industrial items fall outside the scope of the design guide since they are not typically collected through curbside collection that is the focus of this guidance. Non-NIR sortable HDPE, if collected in a source separated or postindustrial stream, can be reclaimed.