Abstract:

Objective Conventional printing methods are characterized by high water consumption and high energy consumption. In order to promote green and low-carbon development and reduce pollution, new printing technologies that save water and energy should be developed. Foam printing is a low-liquor ratio dyeing through the air instead of water as the dye solution, and the foam produced by the combination of these two elements is utilized for printing, so as to achieve water-saving, energy-saving, paste saving, and soft fabric hand. This research aims to prepare foam printing paste and to evaluate its printing performance.

Method By observing and analyzing the foam morphology and combining it with the corresponding printed fabrics, the influences of paste concentration and foam placement time on printing performance were analyzed with using indicators such as the uniformity of foam diameter and the K/S value of the printed fabrics. Factory paste was used as the experimental raw material, and high-definition microscope and X Rite color tester were adopted to observe the foam diameter and the K/S value of the fabrics respectively.

Results The results showed that at the same stirring speed, the foam volume decreased with higher paste concentrations. Observation under a high-definition microscope revealed that the average diameter of the foam bubbles became larger and the degree of homogeneity decreased as the paste concentration increased. At a certain paste concentration, the diameter of the foam bubbles gradually increased and the volume slowly decreased with the increase of the placement time. The higher the paste concentration, the slower the increase rate in diameter and decrease in quantity of foam bubbles. In terms of printing performance, with the increase of paste concentration, the K/S value of the printed fabric showed a tendency to increase initially and then decrease. The color paste residue on the upper edge of the printing screen increased with increasing paste concentration, and the printing pattern became better defined. In the study of the influence of foam placement time on K/S values, the K/S and color difference values of 4% paste concentration were found the most stable, which represents minimal changes in placement time. When the mass fraction of paste is 4%, the foam size distribution is relatively uniform, the fluidity of the printing paste is good, the outline of the printed fabric is clear after printing, and the screen residue is less. When the prepared foam color paste is placed for shorter than 20 min, the degree of foam rupture is smaller, and the K/S value of printed fabric is stable, as well as the color difference is smaller. The wash fastness, rubbing fastness, perspiration fastness, and soaping fastness of the foam printed fabrics could all reach above grade 4, meeting the requirements of use.

Conclusion In this study, foamed color pastes with different mass fractions were prepared, and the characteristics of foams prepared under different conditions were observed by means of microscope. Meanwhile, the printing fabric's K/S value and color fastness were tested and analyzed at different time, which effectively solved the problem that the printing pattern quality would be affected by more foam breakage in foam printing, and reducing the influence caused by more foam bursting. This observation has a strong guiding significance for the implementation of polyamide fabric foam printing process.

Key words: polyamide fabric, foam printing, foam stability, printing color paste, paste, printing property, printing quality