Abstract:

Objective Diacetate fiber is a kind of synthetic fiber which can be naturally degraded, and it is widely used in fashion clothing fabrics. Digital printing technology is an important technical means to broaden diacetate fiber fabrics. Digital printed diacetate fiber fabrics was mainly achieved through high temperature steaming fixation, which was energy and water consuming and also may cause damage to the diacetate fabrics. In order to achieve water and energy saving digital printing process for diacetate fabrics, alternative baking fixation technology for the diacetate digital printing process was put forward.

Method Three printing thickeners were used to pretreat the diacetate fabric. After inkjet printing, the printed fabric was baked at different baking temperatures and times. Through testing the surface contact angle of the pretreated diacetate fiber fabric and the color yield (K/S value) of the printed fabric, the type and amount of pretreatment additives, the baking temperature and time were determined. Confocal Raman imaging technology was used to observe disperse dye diffusion in the diacetate fiber to investigate effect of curing temperature and pretreatment additive concentration on the diffusion of disperse dyes in diacetate fibers. Finally, color management and fastness test of printed products were carried out in the digital printing process under the condition of baking and fixing process.

Results The color yield of baking printed diacetate fabric reached and exceeded that of steaming printed products. Pretreatment of diacetate fiber with thickener KF-388 made the pretreated fabric obtain the same surface contact angle as that of printing paste thickener pretreated diacetate fiber. Laser Raman imaging proved that more dyes diffused into the diacetate fiber when the baking temperature of the printing diacetate fabric exceeded 200 ℃ and above. The fastness test also showed the disperse dyes did not diffused into the fiber when the printing diacetate fiber fabric was baked at 170-190 ℃. Most of disperse dyes exfoliated from the surface of the fiber during the soaping test. The soaping fastness grade of printed fabrics through baking at low temperature was nearly 2-3 which is intolerable to be the luxurious digital printing products. The baking process has a certain negative effect on the hand feeling and other properties of printed fabrics, such as whiteness and strength retention rate and so on. The determination of baking temperature needs to combine the color yield and the performance of printed products. The color management for the diacetate fiber fabric printing process is also key to get an expected color yield. The K/S value of CMYK color pattern after color management almost doubles that of CMYK color pattern before color management.

Conclusion In order to achieve non-steaming and no-washing printing for diacetate fiber fabric, KF-388 is found to be a suitable pretreatment additive, the dosage of which should be more than 2.0%, with the baking temperature of printing being kept at 200 ℃ for 60 s. The printed fabric can obtain the required color yield, hand feeling, whiteness and strength retention rate comparable to the steaming printing process for the diacetate fiber fabric. Laser Raman imaging technology are used to analyze the diffusion of disperse dyes in acetate fibers. The soaping fastness of printed products can be maintained above grade 4. The color management of the digital printing process for diacetate fabric adjusts the total ink output and the linearization of printing process, so as to ensure the quality of diacetate digital printing to achieve what you see is what you get.

Key words: diacetate fabric, non-steaming digital printing, disperse dye, digital printing, Raman microscopic imaging