September 21, 2021
As reported by CosmeticsDesign-Europe, Unilever has filed a patent application for plastic packaging from coloured post-consumer resin plastic, which allows for greater use of recycled coloured and black plastic.
Black plastics are difficult to recycle as the optical sorting systems used in recycling centers cannot recognize them. To address this issue, the plastics industry has worked on creating new black pigments for its plastics that are near infrared (“NIR”) and thus able to be detected by these sorting systems. However, the black plastic produced from recycled plastic using the NIR black pigments was reportedly underwhelming when compared to new plastic due to discoloration.
Unilever’s patent application addresses this issue by using two layers of recycled plastic. The thicker inner layer comprises at least 50% colored plastic waste while the thin outer layer uses natural plastic waste and is colored using a highly concentrated NIR black pigment that masks any discoloration from the inner layer.
The result is a black plastic that is considered acceptable amongst consumers and product packaging that is made up of more than 95% recycled plastic.
Authors: Zhiyao Chen and Meghan King