| visibility |
medium |
high |
high |
| How easily can the marker be detected? |
Dependent
on how homogeneous the marker is and the transparency
of the polymer. |
Marker is in high concentration on polymer
surface. |
Marker is placed externally above the polymer
material. |
| compatibility |
medium |
low |
high |
| How easily
can markers be incorporated? |
Extrusion must be optimized
to ensure good dispersion of marker
in the polymer. |
Marker must be formulated into a suitable
surface coating.
Marker may also need to be food contact safe. |
Marker
need only be compatible with the external label rather
than the polymer. |
| separability |
low |
medium |
high |
| How easy is it to separate the markers from the polymer? |
Once marker is extruded into polymer it is almost impossible
to remove. |
Surface coating may be washed off during
recycling. This must
be optimized for each formulation. |
Removal of labels
is a step already required in many recycling
procedures. |
| reliability |
high |
medium |
medium |
| How likely
is it that the marker will remain detectable? |
Polymer
can be identified even in granulated form. |
Surface coatings
could be partially rubbed/washed off prior
to sorting. |
Label could fall off prior to sorting; cannot
be used for granulated
material. |
| viability |
high |
low |
medium |
| How easily
can the method be adopted by industry? |
Markers can easily
be added to masterbatches of polymers. |
New formulations
must be made to suit marker, polymer, and
application. Applying coating may introduce a new manufacturing step. |
Addition of markers to the print process for external labels
may be relatively straightforward. |
