The RFID tags market is experiencing considerable growth, with the production of RFID tags estimated to reach approximately 35 billion in 2020. Development of conductive silver ink for flexographic printing is urgently required to support the production of environmentally-friendly and low-cost UHF RFID tag printing onto soft substrates (paper or PET). The conductive silver ink for flexo printing contains innovative dispersants. As silver ink demonstrates great dispersion stability and conductivity, a small amount of these dispersants ( < 1 wt%) will be enough for rapid printing (25 m/min). In addition, a multi-scale silver power formula improves the conductivity of silver ink (3,000–10,000 folds) (volume resistivity 21 μΩ.cm), and rheological additives are used to increase the printing accuracy of conduits. This technology can thus compensate for the drawbacks of the traditional etching process, such as generation of wastewater, and the fact that tags cannot be etched onto paper substrates.
Applications & Benefits
ITRI plays the role of a developer of the key material, silver ink. It integrates ink, substrate coating, and printing press manufacturers to co-develop conductive silver flexo printing ink to be applied to the printing of UHF RFID antennae with a resistance of 10–20 Ω, and reading distance of up to 7 m via UHF IC Bonding.