Historical Knowledge of Dyes in Heat Transfer Printing Technology

In ancient times, before the invention of synthetic dyes, only natural dyes derived from plants, animals, or minerals were used for textile printing. Since W. Perkin’s invention of synthetic dyes in 1856, natural dyes—being both time-consuming and labor-intensive to apply and unable to be pre‑manufactured into readily available products—have gradually lost their former prominence.

  However, since 1996, Germany has banned certain azo dyes, as these substances have been found to be carcinogenic, teratogenic, and allergenic. Consequently, attention has shifted toward “environmentally friendly” inks specifically designed for thermal transfer printers. The reintroduction of natural, eco‑friendly dyes has opened up new commercial opportunities for the textile industry, enabling it to tap into emerging markets for naturally dyed and printed products. The market for natural textile products remains a vast, largely untapped frontier.

  Fully harnessing these natural resources requires concerted efforts across multiple sectors to develop appropriate technologies, processes, and products. At present, most research has focused on dyeing with natural dyes and enhancing the colorfastness of dyed fabrics, while applications in printing have received scant attention. This study examines the use of only four natural dyes in textile printing and the resulting printed silk and cotton fabrics, which are employed in apparel, home textiles, and handicrafts. The research offers an additional innovative pathway for producing high-value-added products.

  Currently, the heat-transfer inks available on the market are all chemical dyes. Moreover, substandard ink quality or the presence of certain harmful chemical elements can pose health risks to humans; some inks may even trigger skin allergies or respiratory infections. In response, EU countries have begun enacting legislation to ban specific chemical additives that are detrimental to human health, and exported textiles are now subject to rigorous environmental‑compliance certification and inspection. Plant‑based inks, by contrast, are non‑toxic and environmentally friendly—truly green products—and offer a range of health‑promoting benefits, aligning with today’s consumer trend toward returning to nature and prioritizing wellness.

  Plant-based dyes are entirely natural inks derived from indigenous Chinese medicinal herbs, flowers, tea leaves, fruits, and other botanical sources, refined through a series of processes including grinding, soaking, and steaming. They contain no chemical additives, are non‑toxic and harmless, and textiles and garments dyed with them pose no risk to human health. The manufacturing process for these all‑natural plant dyes is fully protected by proprietary intellectual property rights. Plant dyes represent an ideal new export product, particularly for markets such as the European Union, the United States, and Japan. Moreover, the plant‑based inks used in heat‑transfer printers are 100% natural, free of chemicals, and constitute the optimal alternative to synthetic inks for export.