Study On Preparation And Direct Ink-Jet Printing Definition Of Disperse Dye Ink

Knitted polyester fabrics can satisfy consumer's demands of comfort and fashion due to their good air permeability,extensibility and variety in style of clothes.Direct ink-jet printing of disperse dye ink reduces environmental pollution and responds to the country's call for“energy conservation and emission reduction and green environmental protection”based on the fact that there is no usage of transfer paper.However,the ink droplets can be spread to the surroundings along latitude or longitude direction of the fabric in direct ink-jet printing process because polyester fibers have strong capillary effect and a low cohesive force on ink droplets.Therefore,the printed pattern has a blurred edge and poor printing definition.In order to solve the problem of poor printing definition of direct ink-jet printing for knitted polyester fabrics,the heavy fabrics(230g/m~2)were used for single-side printing whiles the light fabrics(110g/m~2)were used for penetrating printing for this article,based on exploring the relationship between the ink formulation and its physical and chemical properties,the effects of dispersion,humectant and surfactant on the ejection behavior of disperse dye ink were studied.The influences of fabric structure,fabric pretreatment and ink droplets size on droplets diffusion properties was analyzed and the effects of baking conditions on printing definition was also studied.The specific content was as follows:The influences of ink formulations on their physical and chemical properties and ejection behavior of ink were studied.It showed that more disperse dyes decreased in stability at high temperature storage,room temperature storage and freeze-thaw and led to lower drop velocity and larger drop trajectory which it disallowed the ink droplets from being sprayed onto the printed pattern accurately.Compound humectant improved preferably the ink stability of high temperature storage,room temperature storage,freeze-thaw and centrifugation.The drop velocity reduced with an increase in the amount of humectant,but too little or too much humectant resulted in satellites and poor printing definition.Surfactant improved ink stability and reduced drop trajectory,so printing definition was improved.The optimal formula of disperse dye ink was that the mass fraction of dispersion,compound humectant(1,2-propanediol:ethylene glycol:diethylene glycol=2:1:1 w/w/w),surfactant TN-6 and defoamer APE-0050 was 15%,30%,1%and 0.01%respectively,and the viscosity and surface tension of ink was 2.82m Pa·s and 26.9m N·m~-11 respectively,there was no satellites and drop trajectory phenomenon,so the ejection behavior was better.The effects of fabric structure,fabric pretreatment and ink droplet size on diffusion properties of ink droplets was studied.It showed that fabric thickness was closely related to the diffusion properties of ink droplets on the fabric surface,there was a linear relationship between fabric thickness and diffusion coefficient of ink droplets on the fabric surface,and there was also a linear relationship between the ratio of droplet's diffuse width to effective porosity of fabric and printed actual line width.The diffusion coefficient of droplets on the fabric surface was reduced effectively and printing definition was improved when the 4%cationic modification agent B-1 was used to pretreat heavy fabrics.The color saturation and printing definition of the fabric's two sides were basically the same when the 2%cationic modification agent(DM-2558:YR=1:1 w/w)and 1%penetrant M-5 were used to pretreat light fabrics.In addition,when ink droplets size was less than 0.2?L,the diffuse width of ink on fabric in the wale direction was larger than that in the course direction.Whereas,when ink droplet size was greater than 0.2?L,the disperse dye ink mainly diffused along the course direction.The diffusion anisotropy of ink droplets might be influenced by the way liquid migrates from one loop to another for warp-knitted polyester fabrics.The relationship between baking conditions of disperse dye ink and printing definition was studied.It showed that the particles of ink further diffused along the yarn because the temperature of the printed fabric was suddenly increased.Therefore,the actual printed line width was larger as compared to its size before baking.The printing definition of heavy fabrics and light fabrics were at their optimum when the baking temperature was 200?and baking time was 1 min and 30s respectively.