耐久型水性杂化无氟防水剂的制备及其性能

Preparation and application of durable aqueous organic-inorganic hybrid fluorine-free water-repellant finishing agents

针对当前无氟防水剂整理织物耐久性不佳的问题,引入低表面能聚硅氧烷链段和长碳链十六烷基,并通过对硅溶胶乳液进行氨基改性以提高有机硅改性聚氨酯有机组分和十六烷基改性硅溶胶无机组分的界面作用,制备了一种耐久型水性杂化无氟防水剂,并将其应用于涤纶/棉织物的防水整理。研究了防水剂的硅溶胶组分中氨基硅烷偶联剂质量分数、焙烘温度等因素对织物防水性能及防水耐久性能的影响,考察了防水整理织物的表面形貌及对不同液体的防水效果。结果表明:当γ-氨丙基三乙氧基硅烷(KH-550)质量分数为1.5%,焙烘温度为160℃时,防水剂可在涤纶/棉织物表面形成微纳米尺寸的粗糙结构的拒水膜,水接触角可达131.8°;经20次标准洗涤后,织物的水接触角仍可维持在129°,表现出良好的耐水洗性能。

Objective Fabrics with water-repellent finishing have been extensively favored by consumers as one of the most widely used functional fabrics,and hydrophobic coatings and their applications prospects attract interests from both the academic and industrial comunities.However,their application is hindered by some major bottlenecks,especially the poor durability.Therefore,a method for preparing hydrophobic coatings with excellent mechanical stability is urgently necessary.Method To tackle the poor durability of water-repellent finishing fabrics,this study innovatively introduced low surface energy polysiloxane segments and long carbon chain hexadecyl at the same time.A novel durable water-based hybrid fluorine-free water-repellant finishing agents(NSW)were prepared by amino modification of silica sol emulsion to enhance the interfacial interaction between the organic and inorganic components.This modification corresponded to the long-chain alkyl silane modified sol emulsion and polysiloxane modified waterborne polyurethane emulsion respectively.The specific methods used were described below.A polysiloxane modified polyurethane prepolymer(SiWPU)was synthesized through the polyaddition reaction of polydimethylsiloxane(PDMS),polyethylene glycol(PEG),dimethylol propionic acid(DMPA)and isophorone diisocyanate(IPDI).A method of the long-chain alkyl silane and amino modified sol emulsion(Si-NPs)was provided through the hydrolysis polycondensation reaction of hexadecyl trimethoxysilane(HDTMS),silane coupling agent(KH-550)and tetraethyl silicate(TEOS).Si-NPs were added drop by drop in the emulsification process of Si-WPU,silica nanoparticles were adhered to the polyurethane chain segment taking advantage of the difference in the rate of isocyanate group react with amino and hydroxyl group,and isocyanate group exhibits a higher rate of reaction with amino compared with hydroxyl group.Results The chemical composition of Si-NPs and NSW were investigated using Fourier transform infrared spectroscopy.The most stable emulsion was achieved when KH-550 mass fraction was 1.5%(Si-NPs-1.5 and NSW-1.5),and the stability analysis of Si-NPs and NSW-1.5 were demonstrated using particle size tester and Zeta potential analyzer.In addition,the research also focused on the hydrophobic effects of the amount of aminosilane coupling agent in the silica sol.Baking temperature on the property of finished polyester/cotton fabric was also discussed in detail,and the hydrophobic performance and the wash resistance on the surface of finished polyester/cotton fabric were also investigated.It was found that when the mass ratio of KH-550 was 1.5%and the baking temperature remained at 160℃,NSW formed a complete water-repellent membrane.Under the conditions of these application environment on the surface of treated fabric with water contact angle(WCA)of 131.8°,the WCA of the treated fabric dropped by only 2.8°after 20 rubbing cycles and exhibited good washability.The surface morphology of the treated polyester/cotton fabric before and after washing was observed in order to study the water wash resistance on the surface of finished polyester/cotton fabric more intuitively,and the results of SEM images showed that micro-nano rough structures existed on the surface of finished polyester/cotton fabric.Additionally,the repellent effect of the treated fabric on different liquids was also studied to demonstrate the above viewpoint.Conclusion It is confirmed through the research that when the mass ratio of KH-550 is 1.5%and the baking temperature remains at 160℃,the surface of the finished fabric exhibits the best water resistance performance.In view of the poor durability of finishing agents,a method for preparing fully aqueous and organic-inorganic hybrid fluorine-free water-repellant finishing agents was identified,which is to combine the long-chain alkyl silane modified sol emulsion and polysiloxane modified waterborne polyurethane emulsion for the stable preparation of waterproofing agents.