| As an important variety of regenerated cellulose fibers, viscose fiber has been used in many fields, such as textile materials, underwear and decoration. It can not only provide the excellent properties which synthetic fiber cannot provide, but also make up for lack of cotton production. Therefore, viscose fiber always occupies a certain market share. Along with the demand of consumers are more and more high, functional textile has become a hot research topic and water-repellent is an important part. Fluorinated water-repellent agent has been widely used in the water-repellent areas due to its excellent performance both in water and oil repellency. However, PFOS and PFOA, the most important raw materials of fluorochemicals, have been restricted to use because of its potential risk for human health and environment. To develop non- fluoro water repellent agent has great significance. Sol- Gel method is a new way of non-fluoro water-repellent agent. It is of great significance to use this new method in order to replace fluorinated water-repellent agent. In this paper,water-repellent of viscose fiber was researched via silica sol prepared by Sol- Gel method to finish viscose fabric for the construction of rough surface and non-fluorinated water-repellent agent to modify fabric for low surface energy.Silica sol was prepared using tetraethoxysilane as precursor, ammonia as catalyst and ethanol as co-solvent in the experiment. The effects of diameter and polydispersity index(PDI) of silica sol on the water repellency were discussed and results indicate water repellency is not only influenced by silica particle size, but also largely depends on the uniformity of particle size distribution. Good water repellency can be obtained while the diameter of silica sol ranges from 160 nm to 190 nm and PDI below 0.06. It also makes study systematicallyon the preparation condition and factors of silica sol. The optimum condition in this system is molar ratio of TEOS to water/ethanol/ammonia as 1:5:12:0.3 at 40℃ and 1.5h.Experimental results show that viscose fiber only padding silica sol is highly hydrophilic and must be modified by low surface energy substance to obtain water repellency. The effects of Poly(dimethylsiloxane)(PDMS), N-β-aminoethyl-γ-aminopropyl polysiloxane(AEAPS), Hydroxy silicone oil(HSO) on the properties of textile and comparison with different carbon chain length of alkyl siloxane were researched. The results show AEAPS and HSO were better than alkyl siloxane on the water-repellent and softness of textile. Use level of AEAPS to prepare super hydrophobic textile is less than HSO. However, anti- yellowing of HSO is superior to AEAPS.Super hydrophobic textile can be prepared via both directly finishing method by silica sol modified by HSO(m-HSO-Sol) and fractional steps method by first with silica sol padding to build rough surface and second by HSO solution. Fractional steps method is superior to directly finishing method on the washability of water-repellent textile. Based on the research of water-repellent finishing process, results show that the optimum treatment conditions is that using the mass fraction of 2% of HSO or the mass fraction of 0.5% of AEAPS as finishing liquids,dipping the Sol- viscose fiber for 15 minutes, double-dip-double-nip(Rolling residual ratio is 70%),drying in 80℃,baking in 130℃ for 5 minutes. Under the optimum treatment condition, the contact angle of viscose fiber with water is more than 150 degree and can remain above 130 degree after 20 times of washing. |
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