| Natural dyes have attracted widespread attention and research because of its characteristics of environmental protection,harmlessness to human.Ink-jet printing is recognized as the clean printing and dyeing technology,and is in line with the trend of the printing and dyeing industry.This paper combines natural dyes and ink-jet printing technology,develops natural dye inks used for ink-jet printing on fabrics which is conducive to the clean production of printing and dyeing industry.Through the test work on the p H stability,metal ion stability and temperature stability of natural dyes,screening natural dyes that can be used for red,yellow and blue inks.The results showed that the carmine red dye,safflower yellow dye and gardenia blue dye had good p H stability and temperature stability.The metal ions stability of carmine red dye was poor,and of safflower yellow dye and gardenia blue dye were good.So,it is necessary to avoid adding Fe2+ and Fe3+ into inks during the preparation of carmine red ink.Three natural dyes can be used as the basic raw material for ink-jet printing inks.This paper chose alcohols as moisturizers,viscosity and surface tension regulators for Inks.The results showed that with the increase of the amount of alcohol,the viscosity ranged from 3.0 to 5.0 m Pa·s,the surface tension ranged from 30 to 40 m N/m,the conductivity is less than 10000 ?S/cm,and the storage stability was good in two monthes which met the requirements of inks.The inks chose glycerol,diethylene glycol,triethylene glycol and ethanol as alcohol additives,and the total amount was from 15 to 25%.After filtration,the average particle size of inks reduced to 200-250 nm,which met the requirement of the inkjet printer.Through the observation of ink droplet,the parameters such as ink droplet velocity,ink droplet volume,and the angle of trajectory were analyzed and compared.It verified that the ink viscosity ranged from 3.4 to 5.0 m Pa·s and the surface tension ranged from 30 to 40 m N/m were more suitable.The dyeing experiment took hematoxylin as natural dye,and Fe3+ as mordant.The results showed that black fabrics with K/S=11.03,L*=24.62,and C*=1.82 could be obtained when hematoxylin and Fe3+ were mordanted in the same bath at 120°C and high pressure.On this basis,hematoxylin and Fe3+ were used to prepare black ink through complexation,salting out,centrifugation and grinding.When salting out the complex with Na2CO3,the yield after centrifugal drying was the highest;After grinding,the small particles in the ink were poorly dispersed,and were easily agglomerated to form large particles whose size ranged from 20 to 60 ?m which cannot pass through the microporous membrane.Therefore,the preparation of black natural dye inks remains to be studied to find suitable dispersants.The experiment continued to study pre-treatment and post-treatment process conditions.Selecting guar gum as sizing paste,Fe2+ and Al3+ as mordants.The results showed that when the content of guar gum in the slurry is 2.0% and the urea is 6%,the printing effect was the best;Fe2+ changed the original color printed on the silk,and Al3+ had no change;For three inks,the K/S value of fabric were the highest when the content of Al3+ was from 0.3 to 0.4%;After sizing and mordant processing,washing fastness,rubbing fastness and light fastness all reached grade 3 – 4,which met the requirements of textiles.Steaming was beneficial to the fixation of the dye molecules on the fabric surface.The K/S value of the fabric was the highest when the steaming temperature was 100 °C for 30 mins.The longitude friction coefficient of original silk was 0.144,and the latitude was 0.146.After the sizing,printing,and steaming,the longitude friction coefficient was 0.176 and the latitude was 0.180.After washing,the longitude friction coefficient was 0.148,and the latitude was 0.144,indicating that washing can removal the paste on the surface of the silk does not affect the smooth and supple characteristics of the silk. |
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