Factors affecting the quality of reactive dye printing of the textile2012.05.14 09:52
Printing technology has a long history in our country.Early in the Six Dynasties,the Tang and Song dynasties already have the records of “Colored Jiaxie Silk Skirt”.Now the common dyeing process such as tie-dye,batik and textile printing are all originated in china according to the historical research.
With the improvement of the level of the science technology, reactive dyes develop quickly,which has been widely used in printing process.China has explored and produced several mature categories of the reactive dyes successively such as X type,K type, KN type,M type,KE type,KP type with high fixation rate and complete chromatography
1.The general process of the reactive dye printing
Calico-turn the seam cut -desizing,scouring and bleaching-drying- printing-baking–rinsing–triming.
2. Effect of the pretreating process on printing quality
2.1 bleaching process
In order to improve the inherent quality and the appearance quality of the cotton fabrics printing products,we generally need the pretreatment before the dye printing,mainly is the bleaching process so as to remove the fabric pigment,improving the whiteness or color brightness of the fabric.It can remove the residual impurities on the fabrics such as cotton seed hull,wax and so on.
Acid-base properties,temperature,time,concentration and stabilizer of the bleaching solution in the pretreatment process will impact on the fabrics’ whiteness uniformity.Therefore,we should strictly control the process conditions.
2.2. Cold pad-batch method.
The capillary effect of the cotton and other semi-finished products is not high with the cold pad-batch method through practicing.The cotton fabrics which have dealt with cold pad-batch process,to use the imported high efficient scourg agent its capillary effect can reach about 10cm,but changed into some doemestic scouring agent the capillary effect could only be 7~8cm.7~8cm’s capillary effect is feasible on ordinary fabric printing,but the high-grade printing and dyeing products.
Way to slove this problem:use the high-price cold pad-batch scouring agent,or proceeding to baking for a while after cold pad-batching in order to greatly improve the capillary effect.
2.3 desizing scouring process
If the wax on the fabric do not removed clearly during desizing scouring,the residual wax on the fabrics will cause the dye unadsorption,which cause the wax spot in the printing process.
In order to thoroughly remove the wax,you can add some emulsifiers such as peregal and detergents in scourin.To adopt the emulsifiers and sour in one bath can extend the baking time and reduce the wax residue.Especially noticed that through rinsing we must use over 80degrees water,the spray water is forbiden,to prevent the wax adhere to the surface back.
3. Slurry and arranged’s effect on printing quality
Mixing the mill base is very critical,we must gash rip the slurry properly,the thickness must be uniform.Too thick will give rise to impervious or grinning,while too thin is easily staining.In order to prevent the slurry has the intractable or granular solid impurities, the finished slurry must be filtered.
Another important factor is arrangement of the net,usually we first print light-colored and then dark-colored,bright colour ahead and dark colour behind,otherwise it will cause the colors staining.
In short,pre-treatment in reactive dye printing process is very important.If the pretreatment can’t reach the standard or the whiteness is not consistent,the printing will be difficult to proceed.
By Zhu Longyao