Natural pigments for (bio)-plastics colouring

Plant dyes and pigments used until the end of the 19^th century for textile colouring, paints, are now being studied again to meet the demand for natural ingredients. In the field of recycled or bio-sourced plastic polymers, manufacturers are looking to replace synthetic ingredients with natural ingredients, such as coloured pigments. The work carried out by the CRITT Horticole and Couleurs de Plantes has investigated the technical feasibility of colouring bio-sourced plastic polymers, recycled or recyclable, such as PE, PET, PLA and PP with plant pigments in industrial conditions of transformation by extrusion, injection, thermoforming. The results of colour and homogeneity are satisfactory, light stabilities vary depending on the nature of the pigment, and its concentration in the polymer. Regulatory analyses of migrations, heavy metal purity and toxicity have enabled the selection of a range of vegetable pigments suitable for colouring food and cosmetic packaging.