| Pad-dry-pad-steam is currently the most commonly used pad-dyeing method in the industry.However,the pad-dry-pad-steam has a long process and high energy consumption.Due to the direct steaming after fabric padding alkali liquor,the fabric has a large moisture content and slow heating,and the reactive dye is easy to migrate and hydrolyze.The process uses a lot of alkali and inorganic salts,and it does not meet the environmental protection requirements of the textile dyeing and finishing industry.Therefore,a technical route of decreasing the water content of padded cotton fabric in low temperature prior to fixation in the sealing device.Thus,a sealed device was incorporated in the fixing process and a low-moisture content pad-bake-steam technology of cotton fabric dyed with reactive dyestuff was established,with the expectation of improving the dyeing properties of cotton fabric and providing a new idea for the future research of textile clean dyeing and finishing technology.The first part of this paper studies the influence of various types of reactive dyes on the low-moisture content pad-bake-steam technology of cotton fabric.Study on bis-monochloro-triazine reactive red 243,monochloros-triazine/vinylsulfone mixed reactive red198 and reactive yellow 145,and divinylsulfone reactive red 278,the effects of alkali and salt dosage,baking temperature and time on the dyeing properties of fabric were exported,and the effects of different types of reactive dyes on the low-moisture content pad-bake-steam dyeing performance of cotton fabric were compared.The results show that when cotton fabrics are dyed with low-moisture content pad-bake-steam process,the appropriate baking temperatures for reactive red 243,reactive red 198,reactive red 278 and reactive yellow 145 were 170℃,140℃,100℃ and 130℃,and the optimum baking time for reactive red 243,reactive red 198,reactive red 278 and reactive yellow 145 were 5 min,4 min,1 min and 5 min,respectively.The optimum baking temperature and time for the first three red reactive dyes gradually decrease with the increase of the reactivity of the reactive groups,which indicates that the higher the reactivity,the lower the appropriate baking temperature and the shorter the optimum baking time for the corresponding reactive dyes when applied in dyeing cotton fabrics using low-moisture content pad-bake-steam process.The suitable baking temperatures for reactive red 198 and reactive yellow145 were 140℃ and 130℃ respectively,and the suitable baking times were 4 min and 5 min respectively,Which shows that for the same type of reactive dyes,the difference between the baking temperature and time required for dyeing cotton fabrics with a low-moisture content pad-bake-steam process is small.In this paper,the differences of K/S value,color parameters,color levelness and color fastness of cotton fabric dyed by low-moisture content pad-bake-steam technology and traditional pad-dry-pad-steam process were compared under the same dye dosage.The results show that compared with the pad-dry-pad-steam process,the K/S value of the fabric dyed by low-moisture content pad-bake-steam process was improved.When the amount of dye is the same,the K/S value of cotton fabric dyed by low-moisture content pad-bake-steam(substituted alkali)process is higher than that dyed by low-moisture content pad-bake-steam(mixed alkali)process.Which means that the substitute alkali can effectively replace the traditional mixed alkali.The △E*value of cotton fabrics dyed by low-moisture content pad-bake-steam technology and traditional pad-dry-pad-steam process were both less than 1 and not much different.Which indicates that the color levelness of cotton fabric dyed by these two processes meet the requirements of industrial production,and the sealing device does not affect the levelness of fabric.The color fastness to rubbing,soaping and perspiration of cotton fabric dyed by the low-moisture content pad-bake-steam technology all meet the requirements of industrial production. |
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