Due to environmental concerns, progressively more water-based inks are used in conventional and nonimpact printing (NIP) technologies.Water-based flexo inks as well as inks used in NIP technologies use significantly smaller pigment particles than traditional litho inks [Chovancova et al, 2005; Frimova et al, 2005]. Conventional deinking eliminates significantly larger pigments than particles coming from new ink systems. Therefore, novel water-based inks for flexography and inkjet pose a huge issue to recycling facilities. Pressure sensitive label is a significantly larger contaminant of recycled fibers than inks. It was realized that its chemistry and chemistry of novel inks is very similar. Both types of contaminants are based on acrylic chemistry.
This experimental work focuses on deinking of water-based flexo and NIP inks. Elimination of pressure sensitive adhesive in this experimental work serves as a model for ink elimination procedures due to similar chemistries thus similar behavior. The impact of pH on stickies and ink agglomeration during deinking was studied. Experiments demonstrated that acidic pH causes acrylic based inks and stickies to grow in size, which eases their removal.