Printability Analysis on Compostable Films by Flexographic Printing

Aran Hansuebsai and Samatcha Nawakitwong, Chulalongkorn University

Compostable films such as PLA/PBAT and PBAT/starch blends while offer an environmentally friendly, sustainable alternative to oil based films, they also present many challenges in printing applications due to their surface and body structures.

This research focused on the printability of water based acrylic ink on these compostable films, produced in Thailand by flexographic printing. Print quality parameters such as reflectance density, tone reproduction, ink rub resistance and print uniformity were investigated. Results showed that these compostable films were hydrophobic in nature, in combination with fracture and voids of substrate surface. Even the inks can be printed relatively well but showed poor adhesion.  Surface treatment, therefore, was experimented, but having limitation. Higher anilox line screen and printing speed were required to achieve satisfied print quality results. Images of printed surface from SEM and SPM indicated that fracture surface and void of films could lead to defects of print quality, particularly print contrast. This suggests that raw materials mixed with additives are necessary to improve ink laid-down and hold-out on the surface.