Preparation Of Silica Sol And Its Properties As A Stabilizing Agent In The H₂O₂-Bleaching Bath

The paper dwells on the preparation of silica sol and its properties as a stabilizing agent in the bleaching bath. The main aim of the study is to overcome the shortcomings of the wide- ly used stabilizing agent at present.After referring to documents about the categories and preparation of silica sol and related research, the preparation by dissolving silicon powder and alkali silica sol are selected as the technologic method. The right reaction condition is obtained: silicon powder 45g,NaOH 7g/L, the reaction hour for 5 hours, the reaction degree for 82℃. The content of SiO2 in silica sol is 31 %. The pH value is 9.The efficiency of the process is over 81 %.The paper proved that the content of SiO2 in silica sol can be tested by a refractometer. Compared to metage way,this method is more convenient.The paper studied the properties of silica sol as a stabilizing agent. The experiments resu- lts demonstrate that silica sol can effectively inhibit hydrogen peroxide from decomposing in strong alkali medium and high temperature.The fabrics bleached by H2O2 chemick contained silica sol can not be broken.Inhibiting effect of silica sol for Fe³⁺ in peroxide bleaching is researched.It is showed that silica sol can effectively inhibit catalysis of 7.5mg/L Fe³⁺ for hydrogen peroxide in bleac- hing without fabrics.In both processes of desizing and scouring and bleaching,silica sol can prevent catalysis of 3mg/L Fe³⁺ for hydrogen peroxide and impart the fabric better whiteness, yellowness, capillary effect,strength.etc compared with other stabilizers.The silica sol was apllied for one-step desizing-couring-bleaching and two-step desizing- scouring/bIeaching process.Results show that application of silica sol can impart the fabric better degradation rate ,capillary effect and whiteness than that with others stabilizers.