Effects Of Dye Concentration And Diols On The Jetting Properties Of Vinylsulfone-type Reactive Dyes

Reactive dye ink is an important part of ink-jet printing technology for cellulose fiber.For the ink-jet printing of cellulose fabric,the concentration of dye solution is usually high,and the dye molecules are easy to aggregate in concentrated dye solution,which also has an important impact on the physical properties of the dye solution,such as surface tension and viscosity,and these physical properties affect the ink-jet printing effect.Most of the previous studies were focused on monochlorotriazine reactive dyes,while the research about the vinyl sulfone reactive dye is less.Therefore,the four vinylsulfone reactive dyes,Reactive blue 203(B-203),Reactive black 5(B-5),Reactive orange 131(O-131)and Reactive red AS(R-AS),are studied in this paper.The aggregation state of these dyes were studied by UV-vis spectroscopy and Gauss peak fitting.Furthermore,the properties of dye solutions under high concentrated,such as the surface tension and viscosity,were also investigated.In addition,there is an exploration about properties and the ink-jeting performance of dye solutions with ethylene glycol and diethylene glycol.The results showed that,for the four dyes,the aggregation behavior were enhanced by the better planarity structures and high concentration of dyes.The aggregation behavior was also enhanced by the length of conjugated structure,therefore,for R-AS,the aggregation behavior were higher compared to O-131.However,the aggregation behavior of B-5 was lower compared to B-203,and the absorption spectrum of B-203 was red-shifted compared to B-5.This may becaused by that B-203 contains two electronic methoxyl group on the naphthalene ring position.The surface tension of the dye solutions were also decreased with the concentration increaing,this may caused by that the distribution of dye molecules at the gas-liquid interface were increased.The viscosity of dye solution were also increased with the increase of dye concentration,this may induced by that with the increase of dye concentration,the number of dye molecules were increased,and the inter-molecular interaction forces were increased.With the increase of the content of di-alcohol in dye solution,the disaggregation of dye aggregation was enhanced.Meanwhile,the distribution of di-alcohols at the gas-liquid interface were increased,and the surface tension of the dye solution further decreased,the interaction between dialcohols and the dye molecules was increased,and viscosity of dye solution was increased.The surface tension of the dye solution was reduced,which reduces the generation of satellite droplets.With the increasing of viscosity,the droplet trailing was increased.Therefore,by adjusting the surface tension and viscosity of dye solution with diethyl alcohol,stable spherical ink droplets can be obtained.Therefore,by adjusting the surface tension and viscosity of dye solution with diethyl alcohol,the stable ink droplets can be obtained.By studying the effect of ink-jet printing on fabric,it is found that the formation of satellite ink droplets can be inhibited by controlling the amount of diethyl alcohol.And the fineness of ink-jet printing can be improved,while the change of fabric apparent amount was small.