This article is translated from a report issued by the China Dyeing and Printing Association

The Progress and Development of Digital Inks Technology in China

(1) Ink Performance Is Continuously Optimized

The development of nanotechnology and new materials has promoted the development of high-performance digital inkjet inks. Many key technical indicators such as ink fluidity, color saturation, compatibility with printheads and ink supply systems, adaptability to fabrics, as well as key processes such as grinding, filtration, desalination, and dispersion have been continuously improved and optimized. The ink varieties are constantly enriched, and the color spectrum is gradually complete. In addition to the conventional four colors, special color inks such as red, green, royal blue, orange, and gray, as well as fluorescent color inks, can be provided to achieve a wider color gamut application.

In terms of fluidity, it does not block the printhead and can meet the needs of ultra-high-speed printing.

In terms of color fastness, various fastness indicators such as washing fastness, sunlight fastness, and rubbing fastness have been improved.

In terms of safety and environmental protection, it does not contain APEO (alkylphenol polyoxyethylene ether compounds), heavy metals, aldehydes and other chemical components that are harmful to the human body, and is low in VOC (volatile organic compounds), meeting the requirements of safe chemicals. Some companies' products have obtained OEKO-TEX® ECO PASSPORT and Bluesign certifications.

---Disperse Dye Inks

Disperse dye inks continue to be optimized and improved in terms of color fastness and permeability. For example, digital sublimation inks with high sunlight fastness meet the high sunlight requirements of swimwear, outdoor fabrics, etc. Ultra-high concentration digital sublimation inks increase the black density value, with high black saturation, and present a better printing effect for medium and dark patterns. High-penetration digital sublimation inks are especially suitable for long-pile fabrics such as plush, blankets, and carpets. Sublimation inks used for low-weight transfer paper reduce the penetration of ink on low-weight transfer paper, and reduce ink consumption.

---High-temperature Disperse Dye Inks

High-temperature dispersed dye inks achieve higher sunlight fastness by optimizing dyes and ink formulas. Compared with digital transfer, they have high washing fastness and good penetration effect. The heat migration fastness of high energy disperse dye ink is 1 to 2 levels higher than conventional inks, suitable for printing fabrics with high quality requirements such as big-brand clothing.

---Reactive Dye Inks

Reactive dye inks continue to be improved to meet the requirements of good fluidity, high stability, low salt content, bright colors, and storage resistance. However, the relevant indicators of individual colors still need to be improved, such as the reproducibility of black ink, the brightness of royal blue, turquoise, and rose red inks, the wet friction fastness of cyan, royal blue, black, and bright red inks, and the low light fastness of light-colored inks.

---Acid Dye Inks

Acid dye inks have been significantly improved in terms of water fastness and light fastness, especially the light fastness of light-colored inks, which can meet the high light fastness requirements of outdoor fabrics such as nylon. The pretreatment slurry of acid ink further improves the adsorption of acid inks, thereby improving the color fastness, color saturation, and pattern clarity of printed fabrics.

---Digital Textile Pigment Inks

Textile pigment inks include direct printing pigment inkjet inks and digital heat transfer inks, which are used for garment/cut pieces direct inkjet printing (DTG printing), roll-to-roll fabric direct inkjet printing, and digital heat transfer printing (DTF printing). Among them, DTF inks account for more than 75% of the total textile pigment ink consumption, and are mainly suitable for Epson series printheads. With the continuous improvement of technological level, the problems of DTF ink have been effectively solved. The white DTF ink, which has a greater impact on the printing effect, has good whiteness and high covering rate, and the color ink has bright colors.

In terms of color brightness and hand feeling, direct printing pigment inks have gradually approached active inks, and the printing fluency has also been significantly improved. At present, textile pigment ink is widely used in children's clothing, women's clothing, and home textile fabrics. The friction fastness of dark patterns with larger areas still needs to be improved. In addition, the continuous optimization and improvement of the pre- and post-treatment liquids of digital textile pigment inks has played an important role in improving color brightness, fastness, and hand feeling.

(2) Ink Types Are Constantly Enriched

The digital inkjet printing ink industry has formed a relatively complete industrial chain and industrial system. Product categories are constantly enriched. In addition to major inks, new inks such as cationic inks, reductive inks, and latex inks have also been used to further meet the diversified market needs.

---Cationic Dye Inks

Cationic dye inks are mainly used for digital inkjet printing of modified polyester and acrylic carpets. The cationic inks have the characteristics of bright colors, good permeability, and high light fastness. After being treated with a fixing agent, the finished product is washing-free, reducing the consumption of water resources.

---Reductive Inks

The reductive ink developed by Qingdao Yingjietai is mainly used for cellulose fibers such as cotton and linen and their blended fabrics. It has the advantages of high water fastness and light fastness. It can withstand post-treatment such as oxygen bleaching and chlorine bleaching, and can meet special needs such as imitation infrared camouflage.

---Latex Inks

The latex ink developed by Zhengzhou Hongsam Digital has good adhesion and environmental protection, and is resistant to high temperature, stretching, and tearing. It can adapt to more printing media. No sizing or washing is required during the printing process, and the process flow is short. Hongsam latex ink has been used in the fields of leather soft furnishings, shoes, clothing, and bags, and automotive interiors.

(3) R&D and Innovation Capabilities Continue to Increase

The R&D of digital inkjet printing inks and supporting additives focuses on ecological, green, quality and short processes, promoting the continuous formation of differentiated and professional digital inkjet printing solutions to meet broader and more multi-level market requirements. For example, the high-penetration washing-free ink developed for polyester carpet printing; High-sunlight fastness thermal transfer ink developed to improve the sunlight fastness of polyester fabric; High-temperature disperse ink for acetate cellulose fabric developed to improve the printing fastness of acetate cellulose fabric and simplify the printing process; High-sunlight acid ink developed to improve the sunlight fastness of printed fabrics such as nylon and wool; High-penetration and high-concentration flag printing ink developed for printing flag products; Sublimation inks for high-speed machine developed to meet the printing effect under high-speed production mode, showing the improving scientific and technological innovation capabilities of inkjet inks industry.

(4) Development of Short-process Printing Technology for Textile Pigment Inks

The digital textile pigment ink solution focuses on the short-process mode, that is, spraying of pre-treatment liquid, printing, color fixing, and finishing are carried out simultaneously, further giving play to the flexible production advantages of digital textile pigment ink solutions. Zhengzhou Hongsam Digital has developed the Rapid Colour Technology (RCT) digital printing process, which makes the pre-treatment slurry into a sprayable pre-treatment liquid, which is directly sprayed on the fabric through the printhead according to the pattern requirements, and then the pigment ink can be directly printed. RCT technology can achieve the effect of conventional digital printing in terms of ink anti-seepage degree, color brightness and color fastness, while the softness of printed fabrics is better than conventional digital printing. Many digital inkjet printing equipment manufacturers such as Kyocera, MS, Epson, Megani and Hangzhou Honghua can provide integrated textile pigment ink printing solutions, which has promoted the continuous expansion of the application scope of digital textile pigment inks.