Research On Water-Repellent And Oil-Repellent Finishing With Silica Sol For Cotton Fabric

The main ingredient of cotton fiber is cellulose. The cotton fabrics have strong hydrophibic properties. They are easily wetted by the water and contaminated by the oil. In order to become water-repellent and oil-repellent, the water-repellent and oil-repellent finishing is necessary. The surface energy could be lower with the water-repellent and oil-repellent finishing. And the fabrics still have the air-permeability, the air and water vapour could be passed through but not with the water and oil.The water-repellent and oil-repellent finishing was carried out by the sol-gel mothod for the cotton fabrics in this study. With the hydrolysis of TEOS, the ethanol solvent, HCl catalyzer, the sol was prepared. And the sol was modified by the different additives. The cotton fabrics were treated with the double dip and double nip, and firstly dried then curned with the 75% wet pick up. The contact angles were measured. The molar ratio of the TEOS and ethanol and distilled water, the concentration of the HCl, the time and temperature of the preparation, the concentration and structure of the different additives and the curing time were stuied. The contact angle is 139.80°with 4 wt% HTMOS. The water-repellence is attained. The raining rate of the cotton fabric with the sol finishing is 4, the height of the hydraulic pressure is 42 cm and the increasing weight percentage of the water is 12%. It can be seen from the image of the atomic force microscope (AFM) that the surface roughness was attained after the sol finishing with the HTMOS additives. The different coupling agents were used to improve the wash fastness. After 15 cycles washing, the good water-repellence still could be attained with 0.027 mol/Lγ–chloropropyltriethoxysilane. The effect of structure and concentration of the additives on the oil-repellence was studied. The AATCC–998–1992 was used, the rate of 5 was achieved with 20 wt% of FAS.The water-repellent and oil-repellent finishing with the sol-gel method for the dyed cotton fabric had no adverse effect on the washing fastness, rubbing fastness and light fastness. The colour darkened, the shade was slightly changed. The anti-crease properties of the fabric with wash-and-wear finishing and elongation at-break were not affacted. The air-permeability, tensile strength and rigidness were increased. The beetling properties and abrasion resistance were decreased. It can be seen the water-repellent and oil-repellent finishing has no adverse effect on the cotton fabric properties.