The bottoming and color developing equipment of cotton yarn is usually a reciprocating yarn dyeing machine. When the bottom of the reciprocating dyeing machine is used, the white yarn before the bottoming is required to be white and free of stains. The yarn must be straight and loose when the yarn is stretched. The sleeve should be flat to prevent the yarn from overlapping. The concentration of free alkali in the bottom bath should be controlled according to the dyeing properties of the phenol.
When the yarn enters the primer of the yarn dyeing machine, it is important to immerse the yarn in the primer and swing it back and forth, and the time should be controlled between 7 and 10 minutes. After the yarn is bottomed out of the cylinder, after draining for two or three minutes, the cloth is dehydrated by a centrifuge, and the moisture content of the base yarn is controlled at 65% to 70%. After the yarn has been primed, it can be stretched and stringed to develop color.
In the process of applying the reciprocating yarn dyeing machine to the bottoming yarn coloring operation, it is necessary to control the pH value, bath ratio and temperature of the dyeing bath, and the bottoming yarn must be completely immersed in the color developing liquid, and continuously Swing and swing left and right to evenly absorb liquid. The speed of coupling by the chromogenic base can be controlled between five and ten minutes. After the color development is completed, the colored yarn is fully washed, dehydrated, packaged, stretched and dried to obtain a dyed finished product.