The digital revolution in textile printing – requirements and trends for inkjet inks and textile chemistry

During the last years, inkjet printing of textiles has been attracting increasing interest. At present, screen printing is still the major technology for the textile printing industry. However, the digital textile printing market is growing rapidly due to the rising trend in customisation, smaller production batch sizes, requests for faster product availability and higher ecological requirements. Two of the fastest growing applications in digital textile printing are dye sublimation printing and pigment printing.

Recently, the pigment ink market for textile inkjet printing is emerging rapidly. Pigment inks have a lot of benefits such as a high colour strength and high light resistance. They are considered as “universal inks” because they can be applied directly on a large range of textile substrates without sophisticated or environmentally unfriendly pre- or post-treatments. Water-based pigment inks usually require only simple dry heat for a few minutes as a post-treatment process and no special pre-treatment. However, the development of water-based pigment inks is highly challenging in terms of colloidal dispersion stability, jetting reliability and polymer binder chemistry. We introduce DIAMONTEX P as a new water-based pigment ink for inkjet printing of textiles and evaluate the ink in terms of physical ink parameters (such as viscosity, surface tension and particle size), jetting performance and fastness characteristics (rub and wash fastness).

For most digital textile inkjet inks (besides pigment inks), a proper pre-treatment of the substrate is a necessity, e.g. in order to minimize lateral ink bleeding and to maximize colour definition and colour intensity. Fig. 1A shows printing results of our DIAMONTEX S dye sublimation ink printed directly on polyester textile without and with pre-treatment (DIAMONTEX AF-U) while Fig. 1B shows printing results of the reactive inkjet ink DIAMONTEX R printed on differently pre-treated cotton substrates. Fig. 1A highlights the importance of the pre-treatment in terms of contour sharpness (ink wetting and spreading) while Fig. 1B highlights the discrepancy in colour intensity as a function of the pre-treatment. Therefore, the proper pre-treatment of the textile is a key for successful textile inkjet printing.

 Figure 1: Importance of the pre-treatment of textile substrates for inkjet printing, A) inkjet-printed dye-sublimation ink (DIAMONTEX S) with ink bleeding on polyester textile without pre-treatment and reduced ink bleeding on pre-treated polyester textile (DIAMONTEX AF-U); B) inkjet-printed reactive ink (DIAMONTEX R) showing different color intensity on cotton substrates with alginate pre-treatment, modified alginate pre-treatment and synthetic pre-treatment (DIAMONTEX HQ-R)

Figure 1: Importance of the pre-treatment of textile substrates for inkjet printing, A) inkjet-printed dye-sublimation ink (DIAMONTEX S) with ink bleeding on polyester textile without pre-treatment and reduced ink bleeding on pre-treated polyester textile (DIAMONTEX AF-U); B) inkjet-printed reactive ink (DIAMONTEX R) showing different color intensity on cotton substrates with alginate pre-treatment, modified alginate pre-treatment and synthetic pre-treatment (DIAMONTEX HQ-R)

Dr Enrico Sowade of Zschimmer and Schwarz will present an invited talk - "The digital revolution in textile printing – requirements and trends for inkjet inks and textile chemistry" - at the IMI Europe Inkjet Development Conference, 17-18 April 2018 in Frankfurt, Germany.