Improving Fastness To Wet Rubbing Of Deep Color Knitted Fabrics Dyed With Reactive Dyes

Reactive dyes have many advantages,such as broad spectrum range,bright color,easy to use,appropriate price and so on,now becoming the main dyes for dyeing cellulose fiber fabrics.But the wet rubbing fastness of deep color cotton fabric dyed with reactive dyes is poor,usually just reaching level 1-2.So how to enhance the wet rubbing fastness of dyed fabrics is one of the key technologies for dyeing industry.In the dyeing process of Xiangshan Hengda printing&Dyeing Co.,Ltd,the wet rubbing fastness of deep color knitted fabrics dyed with reactive dyes is poor.Therefore in order to solve it,this thesis focuses on-the application of dyestuffs,wet rubbing fastness improver and color deepening agent to increase the poor dyeing rubbing fastness.Firstly,black,dark and red reactive dyes for the pure cotton knitted fabric dyeing are selected,namely the selection of deep primary colors for reactive dyes.By studying the four dyeing performance parameters(S,E,F,R),UV visible absorption spectrum curves,the lifting force curves of a variety of dyes,the dyestuffs are selected.The results showed that reactive red ST-RH,reactive super red RHS are more suitable for dyeing big red fabrics;reactive black DR,reactive black RHS are more suitable for dyeing black fabrics;for yellow dyes,reactive yellow ST-RH,reactive golden yellow DF-3R,reactive super orange RHS are more suitable.Thus,when the apparent depth K/S value is same,compared with fabrics dyed with other dyes,the wet rubbing fastness is enhanced half grade.Secondly,the properties of wet rubbing fastness improvers commonly used are studied.The deep color fabrics dyed with reactive dyes are respectively treated in different concentration of wet rubbing fastness improver A,B,C,D,and E.By measuring the dry and wet rubbing fastness and color difference,finally the results show that the wet rubbing fastness improver A is the best for improving the wet crocking fastness.And through experiments,the best application process of wet rubbing fastness improver A is established as follows:one-dip-one-nip(A 50g/L,pH 5.5-6,pad-pickup 100%)→ drying(100℃)→ curing(130℃× 2min).The application results show that when the fabrics are finished by wet fastness improver A,the dry and wet rubbing fastness are improved obviously,the wet rubbing fastness is enhanced 1-1.5 grade;the dry rubbing fastness is increased 1.5-2 grade.Finally,application of deepening agents are investigated,reducing the amount of dyes to enhance the wet rubbing fastness.The black,red,brilliant blue deep color fabrics dyed with reactive dyes are respectively treated in different concentration of deepening agent A,B,C,D,and E.The results show that the effects that black fabrics are finished by any of deepening agents are very obvious and the effect of C is the best.However,all deepening agents have little effects on red,brilliant blue fabrics.So next the paper only discuss black fabrics are treated by deepening agents.The fabrics dyed with reactive black DR(4%(o.w.f),6%(o.w.f)),the fabrics dyed with reactive black ED-H(4%(o.w.f)、6%(o.w.f))are respectively treated in different concentration of deepening agent A,B,C,D,and E.By testing the apparent depth K/S value of treated fabrics and color difference,the results show that C is the best further.And the effects of concentration of deepening agent C,curing temperature and time,rolling rate,padding method are studied.The research show that best application process of deepening agent C is determined as follows:one-dip-one-nip(C 40g/L(4%(o.w.f)black fabrics),C 50g/L(6%(o.w.f)black fabrics),pad-pickup 100%)→ drying(100℃)→ curing(160℃ X3min).The application results show that when the fabric dyed with 4%(o.w.f)reactive black DR is finished by C,the apparent depth K/S value can reach about 33,the same with the apparent depth K/S value of the fabric dyed with 10%(o.w.f)reactive black DR.When the fabric dyed with 4%(o.w.f)reactive black ED-H is finished by C,the apparent depth K/S value can reach about 28,the same with the apparent depth K/S value of the fabric dyed with 6%(o.w.f)reactive black ED-H.Thus,in the same apparent depth K/S value,the wet rubbing fastness is enhanced 0.5-1 grade.At the same time,it can reduces the amount of dyes,accordingly decreasing the emission of dyeing wastewater,to achieve the purpose of saving energy.