| The traditional H2O2bleaching for cotton fabric could be achieved desired effect in the condition of high temperature, high pH value and longer processing. It can cause high energy consumption, serious damage to the fabrics and a great waste of resources. Therefore, it is propitious to build up low-temperature and high efficient cotton fabric pre-treatment process by the use of an activator to promote hydrogen peroxide bleaching at lower temperature and pH value. In that way can achieve the requirement of energy conservation and emissions reduction.In order to build up low temperature and high efficient pretreatment activation system, cationic activator N-[4-triethylammoniomethyl]-benzoyl) caprolactam chloride (TBCC) was synthesized. Its application conditions on cotton fabric were investigated. There were mainly three parts in this paper:Part I:Synthesis and characterization of TBCC. The two-step reactions were applied to synthesize TBCC. Firstly, chlorine methyl benzoyl chloride, caprolactam and triethylamine were used as raw materials to synthesize4-chloromethyl benzoyl caprolactam in solvent toluene, the yield was88.3%. Then4-chloromethyl benzoyl caprolactam and triethylamine was used as raw materials to synthesize the target product TBCC in the solvent acetonitrile, the yield could reach90.3%. This synthesis process was with high yield, simple and safety.Part II:The mixtures of TBCC with refining agent or surfactant were used for cotton fabric bleaching, and the activation effect was compared with the activation effect of TAED. The effect of concentration of mixture, hydrogen peroxide dosage, NaOH dosage, temperature and time on bleaching was analyzed. The results showed that the combining of TBCC with surfactant, as well as refining agent, could both improve the treatment effect, thereby reducing the amount of activator and production costs. And the effect of TBCC complex was better than TAED.Part III:The application of TBCC in cold pad-batch pretreatment of cotton fabrics was conducted. The influences of activator dosage, hydrogen peroxide solution concentration, NaOH dosage, temperature and time on fabric whiteness, capillary effect and breaking strength were investigated and the result was compared with H2O2/TAED activation system, the optimum conditions were determined. The process was compared with traditional cold pad-batch process and conventional hydrogen peroxide bleaching technology. The result showed that the activation could greatly shorten cold heap of time, reduce the amount of alkali. The capillary effect and breaking strength of the treated fabric were good, which was in line with the development trend of energy conservation in dyeing and printing industry. Then the enzyme refining and H2O2/TBCC activated bleaching system was studied. The two baths in two steps, a bath in two steps and a bath step methods were used to pure cotton knitted fabric. The results showed that the effect of knit fabric treated by a bath one-step short flow processing was closely with the conventional pretreatment. The whiteness, capillary effect and breaking strength all could meet the requirements of the subsequent processing. Therefore it could reach requirement of low temperature, environmental protection and high efficiency in the pretreatment of knitted cotton fabric.The research indicated that it could not only be beneficial to reducing the oxygen bleaching temperature and the amount of alkali, but also improve the bleaching effect and reduce fiber damage through adding activator during cotton fabric hydrogen peroxide bleaching process. If appropriate proportion of compound was used, it could also reduce the dosage of the activator and production cost in the premise of guarantee of bleaching effect. |
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