Printing on biodegradable film

Biodegradable plastics have found an important niche market in single use plastic bags destined to advertising in shops and supermarkets. The increase of its use in applications of packaging and container sector has generated the development and the study of techniques suitable for printing, due to its physic-chemical characteristics.

The specific properties of bioplastic films recommend its use in printing systems where inks are fast dried, as is the case of flexography and rotogravure printing, widely used in the graphic arts industry.

In addition, bioplastic films have a surface tension exceeding 38 dinas/cm. It allows printing without using treatments which increase its surface energy, such as the corona treatments of electric shocks which must be applied to the polyolefin film.

Recently ink series called “ecological” have been developed. It is a very generic concept which tries to position most environmentally friendly ink series. It can refer to its capacity of generating fewer emissions of VOCs (volatile organic compounds) and to the fact that part of its components are obtained from synthesis of renewable resources.

In any case, its compatibility with the requirements established by the EN13432 European legislation plays a key role when we must choose the most suitable ink for printing on biodegradable polymer films. It must not affect the biodegradability of the support material or generate eco-toxicity problems in the final compost, so its formulation must be free from heavy metals.