Nanogels-based ink prepared using electron beam-synthesized poly(vinyl pyrrolidone) nanogels as pigment dispersing and stabilizing agent

Abstract

Dispersion and stabilization of water-insoluble organic pigment particles using nanogels in water-based inks (e.g., inkjet, offset) is a progress opportunity for organic printing ink technology. This work proposes poly(vinyl pyrrolidone) (PVP) nanogels as a nano-structured particle “bumper” for dispersing, wetting, and stabilizing the pigment particles to protect them from flocculation. The expected satisfactory dispersion and stabilization reflects not only quality of formulated ink, but also the finished printed object. The PVP nanogels were prepared in pure water using electron beam-induced chemical reactions, particularly cross-linking, governing particles formation, as well as their final size. Influence of absorbed dose of radiation (2–10 kGy) as well as different molecular weights (MW) of the polymer (PVP-1, ca. 10 kDa and PVP-2, ca. 1400 kDa) on the nanogels formation was studied. The hydrodynamic diameter (Dh) of the PVP nanogels is in the range of around 15–340 nm, depending on the MW of PVP and the absorbed dose. AFM micrographs support the finding of nanoscopic structure of PVP nanogels. The water-insoluble organic pigment (Yellow 12) was used to formulate a water-based nanogels ink. The PVP nanogels in ink play an important role in pigment dispersion/stabilization, reduction of the pigment size, increase of hiding power, and improvement of lightfastness, as well as thermal, water, soap, alkali, and acid resistance properties. This work provides a promising advancement in printing ink and coating technologies due to employing the polymeric nanogels as dispersing, wetting, and stabilizing nanoplatform.