3 Ink for textile digital printing
The ink preparation technology in fabric digital printing formula is one of the key parts in printing consumables.
Digital printing on textiles can be used for digital printing in the papermaking industry. Due to environmental issues and high costs, inks based on organic solvents are not welcome. Water is the best vehicle for ink jets. The main disadvantage of water-based inks is the ease of evaporation. Easy to plug the nozzle; usually add ethylene glycol or methanol as a moisturizer [6]; the choice of pigment depends on the type of the base cloth, acid dye for silk or wool, cotton is the best reactive dye; to improve the color yield, Some additives can be added; some use formaldehyde as an antibacterial agent.
In general, different textile types need to correspond to different dye type ink compositions.
The factors that should be considered when selecting and designing dyes for textile ink-jet inks are: high affinity of the dyes to the dyed fabric, better lightfastness, waterfastness and stainfastness, and low toxicity (by Ames test). For example, in the German patent [7], inks with good binding power to textiles are preferred, CI Direct Blue 86 or Acid Blue 90, Reactive Red 24, Direct Yellow 86 or 132 and Acid Black 194 are preferred. The patent [8] developed a three-primary disperse dye ink with good light fastness and color yield for fabric printing and its printed fabric process. The color ink basically contains a yellow, magenta, and blue disperse dye (A, contains CI Disperse Yellow 42, contains CI Disperse Yellow 149 (B), or contains CI Disperse Yellow 198, contains CI Disperse Red 167 (C), or contains CI Disperse Red 302, containing CI Disperse Blue 60(D) or CI Disperse Blue 87, can be used as a dye dispersant with arene sulfonate or lignosulphonate, heat treated at 180° for 10 min, washed with water, and dried to impart light and rub resistance to the fabric. Grade-fastness and show good colour depth.The pigments studied by some [9] were CI Reactive Blue 4 and CI Reactive Yellow 3 with active amino groups in their structure, which reacted with acrylamide to introduce carbon into the structure. Carbon double bonds, modified with water-based and thermosetting polyurethane resins in formulas to provide water-based inks.Cotton fabrics are printed with this formula ink and show good light fastness and feel under anhydrous washing conditions.
Print color inks usually consist of suitable solvents, colorants, thickeners, bactericides, pH buffers, and antioxidants. According to different types of printed fabrics and the need to design different formulations. Stable and qualified jet ink shall have: suitable viscosity, good fluidity and conductivity, certain surface tension, special particle size, small fluctuations in temperature with temperature, easy drying, no chemical reaction with nozzles, etc. Safe, tasteless and long-term application. For a thermal foaming system, deflocculation is also required [10].
4 Application Development of Light Stabilized Sulfur Dyes and Their Inks
Sulfur dyes generally require the use of sodium sulfide or sodium hydrosulfide, sodium polysulfide as a reducing agent, due to their strong alkali, so leuco dyes leuco tendencies usually can only be used for the coloration of cellulose fibers. In recent years, printing and dyeing wastewater has attracted more and more attention to environmental pollution. Sulfur sulfide is used as a reducing agent to produce sulfur-containing wastewater. Selecting sulfur-free reducing agents has become a research hotspot, such as sodium borohydride, thiourea dioxide, hydroxyacetone, and glucose. The most important is glucose, but since the use of these reducing agent dyestuffs is not stable and easily oxidized by air, it has not been widely used.
As the sulphur dyes are recognized as non-allergic, non-carcinogenic and non-heavy metal ion dyes, the dye-free dyeing and multi-purpose development of such dyes has attracted the attention of dye chemists around the world.
The use of such dyes or modified products in inks has also received increasing attention. Domingo et al. [11] prepared insoluble vulcanized pigments by reacting a leuco dye leucosome with a cationic agent, and then added an aqueous resin and other additives to make the ink. The sulphur dye leucosterics used are CI leuco sulfur black 1, CI leuco sulfur black 2, CI leuco sulfur black 18; CI leuco sulfide red 10, CI leuco sulfide red 14, CI hidden Chromatic Sulfur Blue 3, CI Leuco Sulfur Blue 7, CI Leuco Sulfur Blue 11, CI Leuco Sulfur Blue 13, CI Leuco Sulfur Blue 15, CI Leuco Sulfur Blue 20; CI Leuco Sulfur yellow 9, CI leuco sulfide yellow 22 and so on.
The inks composed of water-soluble sulfur dyes, antioxidants, water and organic solvents developed by Canon Inc. of Japan not only have good storage stability, but also can prevent nozzle clogging, and can form high-quality image patterns of different grades. The typical ink composition is: 14 parts of water soluble sulfur black CI, 10 parts of polyethylene glycol (molar mass 2000), 1 part of sodium erythorbate (antioxidant), 90 parts of water and 0.1 part of Emulgen PP-150 [ 12].
Additional studies based on sulphur dyes for inkjet inks are reported in the German patent [13]. The dyes used were CI anion black 1,2,5,6,7,10,11 or 12 anion or one of the corresponding sulfide black leucomers and R1CH(X)CO2H (R1 = H, C1-4- Alkyl; X = Cl, Br) or their alkali metal salts are prepared and obtained in the form of their alkali metal or ammonium salts with a carboxyl content of 5% to 20%. These dyes can be used to print inks or record liquids and can be stably stored in concentrated form.
German patent EP 0 274 ​​416 reports soluble sulfur dyes which incorporate water-soluble sulfonic acid groups in traditional water-soluble sulphur dyes for use in ink-jet pigments and a corresponding series of sulphur dyes, leuco sulfur dyes which form leucoate salts as parent dyes. Specifically include the following:
CI soluble sulfide yellow 9,16,19,20;
CI soluble sulfur orange 1;
CI soluble sulfide red 2,6,7,10,11,12,13;
CI soluble sulfide blue 2,3,5,7,9,11, 15,19;
CI soluble sulfide green 1,2,3,6,9,19,22,25,27,31,36,37;
CI soluble sulfur brown 8,10,12,15,16,21,51,52,63,88,89,90,91,93,96;
CI Soluble Sulfur Black 1,5,6,8,11; Etc. and the corresponding leucochromic salt of the vulcanized parent dye.
An example of a method for preparing a leuco-salt salt of a sulfur dye is as follows:
The following ingredients were mixed and boiled for 1 h. Then 60° hot water was added to make up the solution to 100 parts. Boiling was continued for 1 h. The mixture was cooled. The mixture was filtered through a 1 μm pore size membrane under reduced pressure, and the resulting filtrate was spray dried. Invented a dye.
The dye preparation components are:
Kayaku vulcanized yellow GGN (trade name) 1 copy
Sodium sulfide (20% aqueous solution) 15 parts
Anhydrous sodium carbonate (10% aqueous solution) 6 parts
Soluble sulfur dyes are prepared as follows:
10 g of Hydrso Black B (trade name) was dissolved in 490 mL of water, and the resulting aqueous solution was then treated with an ultrafiltration apparatus suitable for a membrane having a mean pore size of 0.01 μm, during which 250 ml of the filtrate was filtered to obtain dyes and ratios. For a concentrated solution of a material with a large dye particle size, 250 ml of pure water was added, and this operation was repeated 8 times. The obtained concentrated solution was further filtered on the above apparatus using a film having an average particle size of 0.2 μm produced by the same company, thereby obtaining a filtrate containing only the dye. The filtrate was powdered by spray drying to give the CI Water Soluble Sulfur Black 1 used in this patent.
Water-soluble sulphur dyes are characterized by water-soluble groups in the molecular structure of the dyes, good solubility, good levelness of the fibers, and promising development prospects.
The research group has conducted long-term research on the non-toxic dyeing and multi-purpose development of sulfur dyes, researching and synthesizing a series of macromolecular soluble sulphur dyes containing different water-soluble groups and carrying out multi-functional development for new applications. It is expected that ink-jet printing of textiles can be achieved. It has good application performance in many fields.
5 Conclusion
Although textile digital printing has achieved certain development in the past few years, it still needs further research and development and breakthrough in terms of printing speed, pattern quality and reliability.
In the new century, the world is in the era of rapid development of information and digital. Digital printing has the characteristics of high added value, high profitability, high security, and rapid response. It can meet the requirements of environmentally friendly ecology for the convenience and reproducibility of the printing industry. The high-definition, low-pollution and low-raw-material waste requirements have attracted widespread attention in the textile industry at home and abroad.
It is expected that the creative images displayed on the CAD one day can be printed on textiles by digital ink jets as desired. This will bring about a revolution in textile printing and dyeing technology. According to estimates [15], 12% to 50% of printed products in the recent 10 years will be replaced by digital printing technology. This brings unlimited business opportunities, colorful colors and personality charm will undoubtedly lead the fashion.
All in all, further research and development of new functional dyes such as non-polluting multifunctional sulphur dyes will inevitably bring about unlimited business opportunities for jet printing technology. The breakthrough and maturity of jet printing ink technology will effectively promote the future development of domestic textile digital printing. . â€
Source: Asia Pacific Net India India