Novel Methods To Improve Indigo Denim Performance

Denim Garments are favoured by people with their rough and simple style.With the development of the times and the improvement of people’s living standards,people’s requirements on the performence and quality of denim clothing are higher and higher.The treatment of denim garments usually include three processes: desizing,enzyme washing,and softening.The purpose of this paper is to explore the effects of different treatment conditions in the washing process on the properties of indigo denim,and to obtain the best processing conditions.Firstly,the desizing process of indigo denim fabric was studied.Hydrogen peroxide /ammonium persulfate oxidation system was used used for denim desizing,the desizing temperature,pH,dosage of hydrogen peroxide and ammonium peroxydisulfate were used as the influencing factors,the indigo denim fabric was treated according to orthogonal design,the performance was evaluated by measuring the desizing rate,color,tensile strength,rubbing fastness,water absorbent ability and bending stiffness of the fabric.The further treatment was carried out according to the optimum treatment conditions based on respective property obtained,the values of desizing rate,K/S,strength,water absorbent ability and bending stiffness were analyzed by cluster analysis,the optimum desizing conditions were obtained by comprehensive evaluation of desizing performance: the desizing temperature of 60℃,pH of 7,hydrogen peroxide of 1g/L,ammonium peroxydisulfate of 1g/L.Secondly,combined desizing and cellulase denim biotrentement with ozone pretreatment and composite enzyme was studied.The ozone treatment time,dosage of composite enzyme,enzyme washing temperature and time were used as the influencing factors,the indigo denim fabric was treated according to orthogonal design,the performance of treated fabrics was evaluated by measuring the desizing rate,color,tensile strength,rubbing fastness,water absorbent ability,the number of hairiness and bending stiffness.The further treatment was carried out according to the optimum treatment conditions based on respective property obtained,the values of desizing rate,K/S value,whiteness,strength,water absorbent ability,the number of hairiness and bending stiffness were analyzed by grey-cluster analysis,the optimum desizing conditions were obtained by comprehensive evaluation of treatment performance: the ozone time of 2 min,dosage of composite enzyme of 1 g/L,30 min at 60℃.Further comparison showed that the performance of ozone pretreatment plus composite enzyme treatment under optimized condition was better than that of traditional two-step method.Thirdly,the effect of softening treatment on the properties of indigo denim fabric was discussed.The seven different chemical composition softeners were used to treat the denim fabric,and the further treatments were carried out according to orthogonal experiment design that the impregnation temperature,time,softener dosage and drying temperature were used as the influencing factors.Their effects on fabric softness,smoothness,color change,electrostatic and mechanical properties were discussed.The results showed that emulsified silicone oil gave the best softening performance,soften flake obtained the highest dry rubbing fastness grade,however,the fabric treated by them exhibited the poor antistatic performance and low fastness to sunlight.The composite softener OK has good comprehensive properties,the optimum soft and smooth performance achieved when the immersion temperature being 30℃,time 10 min,dosage of 40g/L,drying temperature of 60℃.The impregnation temperature and time significantly influenced on the fabric strength,and water absorbent ability,color strength and light fastness,the dosage of softener showed the strongest influence on the antistatic property of the fabric.Finally,the effect of wet rubbing fastness on denims is explored.The impregnation temperature,time,dosage of wet rubbing fastness improving agent(WT)and baking temperature were used as the influencing factors,the indigo denim fabric was treated according to orthogonal design,the performance of WT was evaluated by measuring the dynamic friction coefficient,softness and rubbing fastness of the fabric.The optimum results obtained when fabric treated under the impregnation temperature of 20℃,time of15 min,WT of 20g/L and baking temperature of 150℃.The further treatment was carried out by the use of both WT and softener OK,firstly impregnated with WT,followed by drying,baking,then impregnated softener,drying,all properties of fabric in rubbing fastness,softness,smoothness,and others could be obvious improved together.