De-inking is the removal of printed ink from a material before it is recycled. The term comes from paper recycling, and it is now also applied to printed plastic film and packaging.
Ink left on plastic film carries through into the melt. It darkens the recyclate, turning it grey, brown or green, and can release gases and odour during extrusion. De-inking washes the ink off shredded film with water-based surfactant or caustic solutions, often combined with hot washing, so that clear or near-natural granules can be produced from printed scrap. Packaging that is surface printed and developed with design for recycling in mind is far easier to de-ink.
