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Abstract
Many different trials to make acrylic fibers more hydrophilic and thereby enhance dye up take were performed. but they have not been very successful.
On the other hand, disperse dyes are used for dyeing acrylic fibers, because of their good level dyeing and migration properties. But the rate of dyeing is low, and exhaustion is poor, particularly in heavy shades, thus only pale to medium shades are dyed at boiling. (33)
Therefore, the main object of this work is to investigate improvement the dyeing properties of acrylic fabric with disperse dyes, by both bio-treatment and chemical treatment.
The present work is divided into two main parts:
1- Pretreatment of acrylic fabric with brewer’s yeast filtrate with different concentration at various conditions of pH, time and temperature with investigating the effect of this bio-treatment on the wettability, tensile strength, electrostatic properties, and dyeability of acrylic fabric with disperse dyes.
2- Dyeing of the enzymatic pretreated acrylic fabric with disperse dyes involves chemical treatment by using hydroxylamine, copper sulphate and organic solvent, with studying different factors, i.e. copper sulphate conc., hydroxylamine conc., type and conc. of solvent, the pH of dyeing bath, time and temperature of dyeing, on the colour strength of dyed fabric and the fastness properties were evaluated.
1. Bio-treatment of acrylic fabric:
Acrylic fabric subjected to brewer’s yeast filtrate treatment at concentrations of 50, 100, 200, 300 and 400 ml/L for 60 min at 80°C and at pH 7.
The effect of pH was studied by treating acrylic fabric with 300ml/L brewer’s yeast at different values of pH, 6,7,8 and 9 for 60 min at 80°C.
The effect of temperature was also studied by using 300ml/L brewer’s yeast, at 40, 50, 60, 70 and 80°C at pH 8 for 60 min.
The effect of time was investigated by treating acrylic fabric with 300ml/L brewer’s yeast, for 15, 30, 45, 60 and 75 min, at 40°-50°, pH 8.
It could be concluded from the results that the hydrophilicity of acrylic fabric was increased as a result of the change in its chemical structure occurred by enzymatic pretreatment process, and introducing new functional groups into the polymer chains (-COOH).
The dyeability of bio-treated acrylic fabric with disperse dyes was significantly increased by increasing the used concentration of brewer’s yeast filtrate.
Bio-treatment is also accompanied with improved wettability and conductivity of the treated acrylic fabric.
On the other hand, the magnitude of reduction in tensile strength increases with increasing the conc. of brewer’s yeast filtrate.
: The optimum conditions of the pretreatment with brewer’s yeast filtrate were concluded to be 300 ml/L brewer’s yeast, time 15 min, temp. 40°-50° and pH 8.
2. Chemical treatment of acrylic fabric:
Enzymatic pretreated acrylic fabric was subjected to dyeing with disperse dyes in the presence of copper sulphate hydroxylamine sulphate, and dimethyl formamide to improve dyeing properties of acrylic fabric to disperse dyes.
Different factors were investigated in order to optimize the dyeing condition.
The effect of copper sulphate concentration was studied by using 0, 0.5, 1, 1.5 and 2g/l, and 1 g/l hydroxylamine, 30 ml/l OMF and the dyeing was carried out at 90°C, pH5 for 90 min.
Also the effect of hydroxylamine concentration was tudied by using 0, 0.5, 1, 1.5 and 2 g/l, the dyeing was carried at 90°C, pH5 for 90 min with 0.5 g/l copper sulphate, 30 ml/1 OMF.
The effect of type and concentration of organic solvents vas also investigated, two different solvents were examined,dimethyl formamide at a concentrations: 0, 10, 20, 30, 40 and 50 dimethod epichlorohydrine was involved in the dyeing bath at Concentrations: 0, 5, 10, 15 and 20 ml/1 under a constant Conditions of time 90 min, temp. 90°C, pH 5 in presence of 1.5 g/l hydroxylamine and 0.5 g/l copper sulphate.
Effect of pH of the dyeing bath was studied, by dyeing acrylic samples at different values of pH, 4, 5, 6 and 7 at 90°C, with 1.5 g/l hydroxylamine, 0.5 g/l copper sulphate, 30-50 ml/l DMF (depends on dyes used).
The effect of temperature was also studied since the dyeing process was performed at 50, 60, 70, 80, 90 and 100°C for 90 min and pH 6, the dyeing bath including 1.5 g/l hydroxylamine, 0.5 g/l copper sulphate 30-50 ml/1 DMF and at L.R 1: 50.
Finally the effect of time of dyeing process was investigated with different durations of time, 30, 45, 60, 75 and 90 min, the dyeing bath was involved with 1.5 g/l hydroxylamine, 0.5 g/l copper sulphate, 30-50 ml/l DMF, at
100°C, pH 6 and L.R 1:50. The dyeing results indicate that presence of a mixture of copper sulphate and hydroxylamine in the dyeing bath increase substantially the exhaustion properties of acrylic fabric to
disperse dyes.
Also it could be concluded that the presence of organic solvent in the dye bath resulted in an appreciable increase in the K/S of dyed fabric which was related to the concentration of solvent in the dye bath.
It could be concluded from the results that the temperature of dyeing bath and the time of dyeing have an important role in improving the dyeability of acrylic fabric to disperse dyes.
The optimum condition of dyeing was achieved with setting the dyeing bath with 0.5 g/l copper sulphate, 1.5 g/l hydroxylamine, 30-50 ml/1 DMF (depends on dyes), pH = 6, at 100°C for 75 min. and at L.R. 1:50