Preparation And Properties Of High Light Fastness Reactive Inks For Digital Jet Printing

In this paper, to solve the problem of the poor light fastness of reactive dyes in reactive inks for digital jet printing, especially the poor light fastness of red dye, two methods were adopted. One way was to finish the cotton fabrics with the UV absorber containing reactive group. Another approach was to prepare high light fastness dyes. Meanwhile, reactive inks were prepared by these dyes.A kind of UV absorber was obtained from cyanuric chloride, m-aminobenzene sulfonic acid and 2-(2-hydroxy-5-sulfonicphenyl)-5-amino-benzotriazole. The yield of the product is 86.0%. Its purity is 84.0%, and the solubility is 115 g/L at 25℃. The UV absorber was characterized by MS, IR and UV-Vis spectra. The molar absorptivity of the UV absorber is 8365 L·mol-1·cm-1 at 336 nm. As it is hard to make sure that the digital jet printings were printed by one ink, pad dyeing cottons instead of the digital jet printings were used to study influnces of UV absorber on the light fastness of the dye. Reactive brilliant red K-2BP was applied to cotton pad dyeing. The anti-UV finishing of the dyed cotton fabrics was carried with dip-pad-steam process. The relationship between concentration of the UV absorber and the fixation amount on cotton was investigated. The results showed that fixation amount increased with increase of concentration of the UV absorber, and the light fastness of the dye on cotton treated with the UV absorber increased by 0.5 grades.Yellow, red and blue reactive dyes containing 4-(5-hydroxy-3-methyl-1H-pyrazol-1-yl) benzenesulfonic acid were designed and prepared. The dyes were characterized by MS, IR and UV-Vis spectra. The yield of the yellow dye is 57.9%. Its purity is 87.3%, and the solubility is 160 g/L at 25℃. The maximum absorption wavelength of the yellow dye is 392 nm and the molar absorptivity is 2.1×104 L·mol-1·cm-1. The yield of the red dye is 58.7%. Its purity is 89.2%, and the solubility is 240 g/L at 25℃. The maximum absorption wavelength is 517 nm and the molar absorptivity is 2.8 X 104 L·mol-1·cm-1. The yield of the blue dye is 86.4%. Its purity is 77.4%, and the solubility is 210 g/L at 25℃. The maximum absorption wavelength of the blue dye is 607 nm and the molar absorptivity is 2.9×104 L·mol·1·cm-1. The pad dyeing of cotton was carried out with the obtained yellow, red and blue dyes. The lightfastnesses of the yellow, red and blue dyes are 3-4 grade,4-5 grade and 3-4 grade, respectively. The light fastnesses of the commercial dyes, reactive brilliant yellow K-6G, reactive red K-2BP and reactive turquoise K-GL are 6-7 grade,3 grade and 5-6grade, respectively. It showed that the light fastness of the synthesized red dye increases by 1.5 grades compared with that of reactive red K-BP. While the light fastness of the synthesized yellow and blue dyes were not improved.Reactive inks were prepared using purified commercial dyes:reactive brilliant yellow K-6G, reactive red K-2BP and reactive turquoise K-GL as colorants. The influences of the ingredient contents on conductivity, surface tension and viscosity were studied. The formulation of ink was determined. Physical properties of the inks are in line with standard QB/T 2730.1-2013. The inks print smoothly. Reactive inks were prepared using the synthesized dyes. These inks were applied to digital printing. The results showed that the colors are lighter. The inks print smoothly.