Conductive ink and RFID antenna printing

With the rapid spread of RFID technology applications, some large ink manufacturers have also introduced new conductive inks in a timely manner, further promoting the development of the RFID market. It can be said that one of the key factors driving the success of the RFID market is the successful development of conductive inks.

The conductive ink is a conductive composite material formed by dispersing metal conductive particles (silver, copper, carbon, usually silver) in a binder, and after being printed on a substrate, functions as a wire, an antenna, and a resistor. The ink is printed on a flexible or hard material (paper, PVC, PE, etc.) to form a printed circuit. After the conductive ink is dried, since the distance between the conductive particles becomes small, the free electrons move along the direction of the applied electric field to form a current, which has good electrical conductivity and can receive the radio frequency signal dedicated to the RFID. For the printed RFID tag internal antenna, a good conductive ink formulation requires good printability, and the printed ink layer has the characteristics of strong adhesion, low resistivity, low curing temperature and stable conductive performance.

According to the analysis of the NanoMarkets market research company, the conductive ink market will develop into a very large industry. By 2015, the total value of the conductive ink market will be three times the current, reaching $2.4 billion. Due to the attractive market potential, ink manufacturers have swarmed into the conductive ink business, hoping to get a slice of it.

Without the development of conductive inks, there is no application of printing technology in the manufacture of RFID tags. Although the RFID market has been growing, the long-term growth that has been expected for a long time depends on the reduction in the production cost of RFID tags and their large-scale application on common commodities. Printing conductive inks will be an ideal solution to reduce the cost of RFID tag production. At present, conductive inks for RFID antenna printing account for only a very small portion of the entire conductive ink market. However, the industry believes that in the next 10 years, the share of conductive inks used in printing RFID antennas will continue to grow rapidly in the entire conductive ink market. At the same time, the share of conductive inks in the entire ink market will also increase significantly.

The currently successful application field of RFID technology is smart card. It adopts HF RFID technology. The most prominent feature is that the reading distance is relatively short, the cost is low, and the reliability is high. It is more suitable for IC bus cards and bank cards. At the same time, the demand for remote reading systems in various industries is also very strong, which promotes the application of UHF RFID technology. Moreover, UHF RFID tags can replace traditional bar codes in areas such as supply chain management for product tracking and identification. However, for UHF RFID tags and related systems to achieve large-scale commercial applications, it is necessary to overcome the biggest obstacle to the high cost of tag production. Etching has always been the most common method for making RFID antennas. Etching RFID antennas must undergo both dry etching and wet etching, which makes it more difficult to reduce production costs. At the same time, etching the RFID antenna also requires a chemical treatment process, which generates a large amount of waste liquid during processing, so etching the RFID antenna is considered to be a very environmentally unfriendly process.

Conductive inks are considered to be the only technology that has gained worldwide acceptance. The method of printing an RFID antenna with conductive ink only needs to undergo a dry process, and does not generate a large amount of waste liquid like the etching process, and is considered to be a more environmentally friendly and efficient process. In addition, the use of conductive ink to print RFID antennas can achieve mass production, and the scrap rate is relatively low, the antenna performance is stable, and the overall production cost of the RFID tag can be greatly reduced. Therefore, it can be said that printing RFID antennas with conductive inks will be the preferred process for making HF RFID and UHF RFID antennas.

In addition, the use of screen printing conductive ink process can also reduce the production cost of RFID tags, one of the reasons is that the investment in the introduction of printing equipment is much cheaper than the introduction of copper etching equipment. In addition, since there is no need to add additional investment to meet the environmental requirements during the printing process, the production cost and equipment maintenance cost are lower than the copper etching method, thereby reducing the cost of the RFID tag.