High electrical conductivity waterborne inks for textile printing

Printing of conductive inks is an attractive means of manufacturing of electronic components on flexible substrates including textiles. The textiles thus produced are often referred to as “e-textiles.” When high electrical conductivity is required, inks are preferably made from metal nanoparticles such as silver. However, such inks are expensive and generally not known to withstand severe washing and wearing to which textiles are normally subjected during the end use. In the present study, which forms a part of a larger study by the authors, waterborne dispersions of conductive grades of carbon black were converted into finished inks followed by washing and creasing tests to ascertain the durability of these inks. We found that not only were the inks stable after letdown with different binders, but they possessed high electrical conductivity despite the fact that the final pigment loading in all of the formulated inks was significantly less than the pigment loading that is generally found in commercial conductive inks. In addition, the electrical conductivity after washing and creasing tests of the formulated inks was found to be significantly greater than that of the tested commercial conductive inks. This shows that using large surface area, highly conductive grades of carbon black pigments in relatively small amounts in inks for textile printing is beneficial in achieving some of the critically required characteristics, particularly those pertaining to durability of the ink film.