Monitoring And Controlling The Dyeing Rate For Nylon Fabric

Nylon is currently the world’s second largest production of synthetic fiber, it is widely used in various fields of civil and industrial fabrics of clothing with its excellent performance. However,the uneven dyeing phenomenon of nylon fabric is a more prominent issue, and it has been the very focus issue for dyeing workers, especially for the emergence of low liquor ratio and ultra-low liquor ratio dyeing technique in recent years, which is mainly to meet the requirements of energy saving. It made more stringent requirements for the levelness of nylon fabric. For a long time,when the equipment and fabric are determined in dyeing factories, one of the main ways to solve this problem is adding leveler, it can improve the dye transfer and slow down the dyeing rate; the second way is to reduce the whole heating rate or rise the temperature separately, it can also reduce the overall uptake rate and improve the dyeing levelness. These methods are essentially to control the dye’s exhasution rate in dyeing process. Also they can achieve good results. But adding leveler will increase the difficulty of sewage treatment and decreasing the heating rate will increase the whole dyeing time, which decreased the equipment utilization. The technology of controlling dyeing rate for nylon fabric in this text should be a relatively new direction on nylon dyeing for clean production dyeing process.According to the recent studies of quantitative controlling the dyeing rate on natural fiber(cotton and wool) in Donghua University, by online testing the dye concentration, taking the non-linear temperature program as the main controlling factor in the constant dye, aiming to controlling the dyeing rate, an effective way of controlling the dyeing rate of nylon, which belongs to synthetic fiber was explored in this text. Then the experiment was continued in low liquor and ultra-low liquor dyeing conditions to find out the characteristics and applicability of controlling the dyeing rate of individual dyes and mixing dyes.There is no existing dyeing application for online testing now, low liquor and ultra-low liquor dyeing application was needed to build by myself. Then in order to avoid the fabric can not contact the dyeing liquor sufficiently, the dying equipment was desighed to filling the fabric,which shape is like the word “U”. Next the dyeing liquor can pass the pipe by the dynamic function of constant flow pump, playing the dyeing liquor circulation role, then ensured the sufficient contaction between the fabric and dyeing liquor. At last, according to the experimental requirement, we tested a varity of pipe materials, and finally choosing to use the polypropylene film pipe and elongated latex balloons. They both have the properties of thermal conductivity,flexible, heat resistant strength, good chemical resistance and easy to obtain.The experiment studied the dyeing rate quantization control in different dyes’ dyeing process using isothermal staining method. Then exchange the dye dosage, bath liquor and mixed dyeing,developing the influence to uniform dyeing process, and found out the revised method.The research results show that the experiment can realize to control the dyeing rate in physical instead of chemical method. When the dyeing dosage changed between 0.5% and 2.0%,we can use the method of “△E-△t” to revise the curve of dyeing rate, and obtain the desired result. If the bath ratio is between 1:10 and 1:4, the original 1:10 constant speed control technology can use to the bath ratio which is changed within two levels, but it can not use to 1:6 or1:4, so a new isothermic dyeing method should be developed. When the experiment was done with mixed dyes, we can use the method of dosage ratio control temperature to quantitative control the dyeing rate.