Study On Open Width Dyeing Process Of Cotton Knitted Fabrics

Pure cotton knitted fabrics are deeply loved by people because of their soft texture and comfortable wearing characteristics.With the increase in the demand for knitted fabrics for outer clothing,the demand for the processing quality of knitted fabrics increases.The traditional printing and dyeing of knitted fabrics adopt a rope-like intermittent process.Which makes the cloth surface easy to fuzz and wrinkle,long processing time and low production efficiency.The open-width printing and dyeing technology of knitted fabrics is an effective way to produce high-quality knitted fabrics,which can not only improve the problem of fabric defects in the production process,but also greatly improve production efficiency.With the funding of the National Key R&D Program,this research group participated in the research and development of a pad-baking-steaming open-width dyeing production line for knitted fabrics.In order to cooperate with the operation of the production line,this paper studied the open-width dyeing performance of reactive dyes with different structures,optimized the open-width dyeing process conditions of knitted fabrics,obtained a suitable dyeing process,and provide a reference for the selection of the dyeing process parameters of the open-width continuous dyeing production line of knitted fabrics.This article first selects the reactive dyes with three different structures containing bi-vinyl sulfone active group,bis(monochloro-s-triazine)active group and hetero-bi-active group(monochloro-s-triazine and vinyl sulfone active group),respectively,using the traditional exhaust dyeing process and the pad-dry-pad-steam dyeing process is used to dye cotton knitted fabrics.By comparing the dyeing lifting power with K/S value and color parameters,it is found that the bi-vinyl sulfone reactive dyes and the hetero-double reactive reactive dyes are more suitable for the pad-dry-pad-steam dyeing process than the bis(monochloro-s-triazine)reactive dyes.Its dyeing lifting power is good,and the K/S value of the dyed fabric is equivalent to that of traditional exhaust dyeing process.However,the dyeing lifting power of the bis(monochloro-s-triazine)reactive dyes using the pad-dry-pad-steam dyeing process is poor,and the K/S value of the dyed fabric is poor when dyeing deep colors.The K/S value is lower than traditional exhaust dyeing process.Through the comparison of color parameters,it is found that when the dye color is light and bright,the C~*value of the fabric after dyeing by the pad-dry-pad-steam dyeing process is higher,and the vividness of the color can be maintained more.In order to obtain the best parameters for dyeing with different structures of reactive dyes in the pad-dry-pad-steaming dyeing process,the single-factor variable method is used to optimize the alkali dosage and steaming time of the pad-dry-pad-steaming dyeing process.The best dyeing process conditions for the pad-dry-pad-steaming dyeing process of bi-vinyl sulfone reactive dyes when dyeing light colors are:alkali dosage 15-20 g/L,steaming time 2-3 min,when dyeing deep colors,the best dyeing process conditions are:alkali dosage 25-30 g/L,steaming time 4 min,the knit fabrics containing monochloro-s-triazine and vinylsulfone reactive group reactive dyes for the pad-dry-pad-steaming dyeing process when light color dyeing.The best dyeing process conditions are:alkali dosage 10-20 g/L,steaming time 3-4 min,when dyeing deep colors,the best dyeing process conditions are:alkali dosage 20-30 g/L,steaming time 4-6 min.For the bis(monochloro-s-triazine)reactive dyes,the best process conditions for dyeing light colors are:alkali dosage 30-35 g/L,steaming time 7-8 min.Finally,The optimized process parameters are used for the dyeing of knitted fabrics in the open-width pad-dry-pad-steaming dyeing process,and the dyeing effect is compared with the fabric samples dyed by traditional exhaust dyeing.The results show that the dyed fabrics of the pad-dry-pad-steaming dyeing process have high color depth.Compared to traditional exhaust dyeing fabrics,and its level dyeing is equivalent to traditional exhaust dyeing,the color difference"?E"<1,the dry rubbing fastness of the fabrics dyed by the two processes is up to level 5.At the same time,the cotton is dyed by the pad drying process The dry rubbing fastness and soaping fastness of the fabric are equivalent to those of traditional exhaust dyeing,both reaching level 4 or higher.The wet rubbing fastness is half a grade lower than that of the traditional exhaust dyeing process,but they all meet the needs of actual production.