Short-process Pad Dyeing Of Cotton/brocade Fabrics With Reactive Dye

In the textile industry,cotton/polyamide fabrics have excellent properties and are one of the most commonly used two-component fabrics.Twocomponent fabrics have the advantages of both fibers compared to singlecomponent fabrics.However,because the different properties of cotton and polyamide fibers,the traditional dyeing technology has the following two problems,(1)at present,cotton/polyamide fabrics generally use the active/neutral double dye dyeing method,which has a long process,cumbersome process,low efficiency and cannot be continuously produced.(2)Dyeing process resource consumption,low utilization rate of dyes,auxiliaries,wastewater discharge.The above two points are not consistent with the clean dyeing theory,so it is urgent to make a breakthrough in cotton/polyamide dyeing technology.In order to solve the above problems,this paper first abandoned the traditional reactive/neutral double dye dyeing method,using reactive dye single dye dyeing.By studying the dyeing effect of more than ten kinds of reactive dyes on polyamide fiber in cotton/polyamide fabric,the influence of reactive group,hydrophilicity and hydrophobicity,molecular weight on the dyeing effect of polyamide fiber was investigated.The results show that when the dye reactivity is too strong,the color yield of nylon fiber is low.The stronger the hydrophobicity of the dye,the higher the affinity of the dye to the nylon fiber;The molecular weight of the dye is between 650-700,and the fixation rate is the highest.Then,based on the properties of cotton,nylon and reactive dyes,the twobath and two-step pad dyeing process of reactive dye-cotton/polyamide fabric was determined.A variety of reactive dyes were used to dye cotton/polyamide fabrics.The effects of acidity and alkali selection,alkali concentration and twice steaming time on the dyeing effect of cotton fiber and nylon fiber were studied.The results showed that the maximum K/S value of the fabric was about 20,the color fastness was basically maintained above grade 4,the permeability was good,and the color difference was small.The process has strong universality,excellent dyeing effect and good homochromism for reactive dyes.The drying process consumes a lot of energy,so the possibility of eliminating the drying process before soaking lye rolling is explored.Reactive red 218,reactive blue 19 and reactive yellow 15 were selected to study the dyeing effect of the new process.By comparing the K/S value of new and old fabrics,it is found that the more reactive the dye is,the less the change of K/S value is.Therefore,the drying process before dipping and rolling lye can be removed for reactive dyes with two bath and two step dyeing process.The two bath and two step pad dyeing technique proves that reactive dyes need to dye cotton fiber and nylon fiber under alkaline condition and acid condition respectively.By introducing sodium trichloroacetate(TCA)into the dyeing solution,an adaptive p H adjustment system was developed,and finally a one-bath one-step pad dyeing process of cotton/polyamide fabric was designed.Steam will decompose TCA to produce alkaline substances to change the acid and alkali of the dyeing solution,providing a suitable color fixing environment for cotton and nylon fibers.Cotton/tapestry fabric was dyed by reactive red 218 in a one-bath one-step process.The results showed that the ideal color depth and homochromaticness could be obtained when the concentration of dye and sodium trichloroacetate were 25g/L and 20g/L,the initial p H value of the dye was 5 and the steaming time was 25 min.In this paper,three reactive dye pad dyeing processes for cotton/polyamide fabrics are designed.The three dyeing processes are more suitable for clean production with low energy consumption,low carbon emission and high efficiency than the current commonly used cotton/polyamide fabric dyeing technology.