Nano-silica from rice husk (nano-RHS) was synthesized and used in a coating agent to enhance the
flexographic print quality of bleached kraft liner. The rice husk was refluxed with a 2 M HCl solution and
calcined in a muffle furnace at 650 ◦C for 4 h. The particle size ofthe resultant rice husk ash was reduced to
a very fine nano-RHS by hexadecyltrimethyl ammonium bromide. The synthesized nano-RHS in different
proportions – 1%, 2%, 3%, 4% and 5% (w/wresin) – was added to a water-based coating agent consisting of
acrylic resin. The coating agent with nano-RHS additive was applied by gravure rolling onto the surface
of a 170 g/m2 bleached kraft liner 3–4 m in thickness. The flexographic print quality was determined
with printing details of 31.5 lpc using water-based process colors. The results indicated that the coating
agent with 1% nano-RHS was the most promising for improving the flexographic print quality on the
bleached kraft liner. At this fraction, the best print quality in terms of high sharpness of fonts and texts,
line art, realistic image, and TVI curve (under the requirements ofISO 12647-6) were achieved. In addition,
low tone-value and E*abwith a large, three-dimensional color profile and the widest color gamut were
obtained.