Method for darkly dyeing PLA (polylactic acid) filament yarn fabrics

The invention discloses a method for darkly dyeing PLA filament yarn fabrics, which belongs to weaving printing and dyeing industry and comprises the following steps: carrying out low-temperature plasma treatment on the PLA filament yarn fabrics in low-temperature plasma equipment, wherein the treatment conditions are shown as follows: power is 20W-100W, time is 10S-100S, and treatment atmosphere is air; soaking the treated PLA filament yarn fabrics in a crylic acid solution the weight percent is 10-50 percent for 30-200 min; and then dyeing the PLA filament yarn fabrics with dispersed dyes at the temperature of 100 DEG C for 40 min to achieve dye uptake balance. In the invention, the plasma treatment is adopted to carry out physical and chemical modification on the surfaces of the PLA filament yarn fabrics to realize the constant-pressure low-pressure dyeing of the dispersed dyes on the PLA filament yarn fabrics, and the deep dyeing property is greatly improved.