Conductive property of nano silver ink on flexographic prints

Abstract

This research is aimed to study the possibility of applying a flexographic printing with nano-silver ink for fabricating conductive lines on paper and film substrates. The rheological behavior of ink and the varying effects of anilox line screen on printing speeds and print quality were investigated. Printed layer thickness and its resistivity were analyzed. It was found that non linearlty of ink gave little effects on relationships between image parameters and printing conditions. It is because the viscosity of nano-silver ink is much lower than that of common water based flexographic ink. Press setting, packing material and rubber ink fountain roller should be in good conditions to protect printing problems such as ghosting and wave patterning. Results showed that anilox line screen did not relate well to print quality, while higher printing speed rather gave preferable printed results such as better resolution and low spreading, but non-homogeneity of solid area was still existed. The smallest text size which could be produced was 6 pt for positive font and 8 pt for negative font. Anilox line screen 600 lpi and printing speed 60 m/min was proposed as best condition in this study. Image of 0.1 mm finest line with about 10% width spreading and 5 µm thickness was achieved. An average sheet resistivity was at 1.26 ± 0.06 /cm2. This obtained value is a little larger than that of practical RFID devices.