Study On Low Urea Printing Of Viscose Fabirc With Reactive Dyes

Reactive dye has been widely used in the dying and printing of cellulose fibersfor its good performance.Viscose fabric possessing lots of good properties such asbright luster,good moisture absorption, soft,drapability, dying easily and so on, waswidely employed in clothing,interior decoration fields.However, due to the highdegree of crystallinity of viscose fiber surface with a dense cortex,more urea as aco-solvent in reactive dye printing was required to absorb more moisture to swellfibers in the steaming, thereby promoting dye and fiber fixation.However, urea decomposes to produce CO2and nitrogen compounds undercertain conditions. Nitrogen compounds will accelerate the growth of algae and causewater eutrophication. Currently the emissions targets of ammonia nitrogen in dyeingwastewater become more stringent. Therefore the study of low urea printingtechnology has become a major issue in dyeing industry.In this paper,agent B and agent N containing alcohol ether structure were appliedin viscose fabric reactive dyes printing to partial instead of urea.The impact of K/Svalue,color fastness and permeability of viscose fabric reactive dye printing is studiedby changing the replacement rate of agent,the dosage of NaHCO3and resist salt S andsteaming time.Single factor and orthogonal experiments were made to figure out thebest replacement ratio and printing conditions while the ammonia nitrogen contentwas determined.Using Fourier Transform Infrared Spectrum preliminarycharacterization of the structure of fertilizer B and N; At the same time,by testingwater retention and moisture retention of viscose fabric, printing viscosity index(PVIvalue) and rheological property, thixotropy, hold water and stability of mill paste,themechanism of low urea viscose fabric printing was analyzed.The result showed that the best replacement rate of agent B and agent N were80%and100%respectively with dye dosage charging2%.The best printing conditions were as follows:agent B7%, NaHCO33.5%, resist salt S1.5%, saturatesteam steaming10minutes; agentN5%,NaHCO33%, resist salt S1%,saturated steamsteaming10minutes.The K/S value of the viscose printed products after the two agenttreatment wererelatively close to that after urea printing for the selected9kinds of reactive dyes，andhave good permeability. And the viscose printed products could achieve good washingfastness and rubbing fastness. The content of ammonia nitrogen ofagent B and agentN with8%content4.71mg/L、0.21mg/L respectively, which were obviously lowerthan that of urea (8.83mg/L).Analyzed by low urea printing mechanism, the moisture regain of urea, agent Band agent N were close which showed that all of them could improve thehygroscopicity of viscose fiber. According to liquid rate treated by different agentswith different minutes,the moisture rate of agent B was up to33.6%,and that of agentN was12.8%, slightly lower than that of urea(14.7%). The nitrogen content of agentN was the lowest(1.63%) by element analysis The effect of rheology and thixotropyof the original printing paste showed that the effect of agent B and urea was similar,with the increase of dosage,exhibits Prominent shear-thinning behaviors ofPseudoplastiefluids. The shear thinned phenomenon is more significant. The lower theviscosity response rates, the greater the original structure of the paste viscosity,thixotropy, and not suitable for printing fine decorative pattern. while agent Nshouldn’t be.With this condition, the hold water of the original printing paste werebetterthan urea, and the original printing paste also had a good stability within48hours.