| Wool is a typical kind of natural protein fiber with many excellent properties such aselasticity, warmth retention and abrasion resistance. However, the scale structure on the surfaceof wool fiber severly affects the wettability and printing property. In order to improve the inkjetprinting property of wool fabric and solve the problems of high wastewater, high pollution, highenergy consumption and low value added in traditional printing pretreatment process, dielectricbarrier discharge (DBD) atmospheric pressure plasma is applied on the pretreatment of woolfabric for digital printing and the printing property is improved significantly in this paper. At thesame time, atmospheric pressure plasma dry treatment is used with digital printing technology toachieve continuous production of wool printed fabric. The paper is divided into three parts:Firstly, according to the atmospheric pressure plasma discharge characteristics, eightdifferent kinds of materials are applied to research into the burn through prevention effect ofwool fabric separately. On this basis, further research of gap spacing on the burn throughprevention effect of wool fabric is executed, and a new burn through prevention method of woolfabric with atmospheric pressure plasma treatment is constructed, meanwhile providing a newidea for filamentary discharge turning into glow discharge under ordinary conditions of pressure.The optimization results indicate that the method not only avoids burning through of wool fabric,but also has a positive significance for surface modification of wool fabric.Secondiy, wettability improvement and uniformity of wool fabric after plasma treatment arechosen as the evaluation index. By optimizing atmospheric pressure plasma output power,treatment time, gas flow rate and gap spacing, the atmospheric pressure plasma pretreatmentconditions of wool fabric are as follows: output power60W, treatment time60s, gas flow rate1.5L/min, gap spacing2mm. Under above conditions, the alteration of surface micromorphology,chemical composition, wettability, weight loss, aging effect, whiteness, strength and handle ofwool fabric before and after plasma treatment are compared by the means of scanning electronmicroscop(eFESEM), X-ray photoelectron spectroscopy(XPS), optical contact angle measuringdevice, etc. The results demonstrate that the scale layer of wool fiber is etched and oxidative degradated after atmospheric pressure plasma treatment. The carbon concentration substantiallydecreases, the concentration of oxygen significantly increases, but the concentration of sulfur donot obviously changes; the wettability is significantly improved, the weight loss is only about2.6%; the fabric wettability declines with the prolonging of the storage time; the breakingstrength increases and the whiteness of plasma treated fabric had no obvious change, but thehandle decreases.Finally, the influence of sodium alginate, urea, sodium sulfate, glycerin and paste pH valueon K/S value of wool fabric in traditional screen printing are investigated, and the optimumprescription is established as follows: sodium alginate3%(o.w.p=on weight of paste, similarlyhereinafter), urea5%(o.w.p), sodium sulfate7%(o.w.p), glycerin5%(o.w.p), ammonium sulfate1%(o.w.p), penetrantJFC1%(o.w.p). The paste is made according to the optimum prescriptionand then applies it to the sized wool fabric, the ink-jet printing technology is used to print patternon fabric at last. The results show that the K/S values of wool printed fabric have a significantlyimprovement, the dry and wet rubbing fastness can reach grade4and grade3separately, and thesoaping fastness can reach grade4-5. In addition, the digital printing fabric exhibits a much moreintense colouring compared with traditional screen printing, the outline sharpness of fabric isgood and the pattern barely bleeds. The technology can meet the requirements of industrializedproduct. |
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