Effect of Various Conditions on Disperse Dyeing
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The document discusses the effect of various conditions on disperse dyeing. It explains that temperature, pH, and time all play important roles. For dyeing with disperse dyes, a temperature above 100°C is needed for fiber swelling. The dye bath pH should be between 4.5-5.5 for satisfactory dye exhaustion. Time is also crucial - if not maintained properly, it can result in poor color fastness and an unacceptable dyeing outcome. Maintaining the appropriate conditions is essential for effective disperse dyeing.
Effect of Various Conditions on Disperse Dyeing
- 1. GREEN UNIVERSITY OF BANGLADESH Department Of Textile Engineering ASSIGNMENT Remarks: Course Code : TE 305 Course Title : Textile Coloration II Submitted To: Name : Mr. Md. Mahbubur Rahman Designation : Senior Lecturer Department : Textile Submitted By: Name : Md. Rakibul Hassan ID : 183014057 Section : E1 Department : Textile Date Of Performance : 27 July 2020 Date Of Submission : 04 August 2020 Assignment Topic : Effect of various conditions on disperse dyeing.
- 2. Effect Of Various Conditions On Disperse Dyeing Introduction: Disperse dye is one kind of organic substances which is free of ionizing group. Disperse dyes are less soluble in water and used for dyeing synthetic textile materials. Disperse dyes is mainly used for dyeing polyester yarn of fabric. in the other hand, Reactive dyes are used for coloring cotton or cellulosic fiber. A class of slightly water-soluble dyes originally introduced for dyeing acetate and usually applied from fine aqueous suspensions. Disperse dyes are widely used for dyeing most of the manufactured fibers. Dyes are colored, unsaturated organic chemical compounds capable of giving colour to a substrate (a textile), i.e. colouring or dyeing it. Example of disperse dye The term “disperse dye” have been applied to the organic colouring substances which are free from ionizing groups, are of low water solubility and are suitable for dyeing hydrophobic fibres. The dye has derived its name for its insoluble aqueous properties and the need to apply it from an aqueous dispersion. Of all the dyes, they are of the smallest molecular size. Disperse dyes have substantivity for one or more hydrophobic fibres e.g. cellulose acetate, nylon, polyester, acrylic and other synthetic fibers. The negative charge on the surface of hydrophobic fibres like polyester can not be reduced by any means, so non-ionic dyes like disperse dyes are used which are not influenced by that surface charge. Effect of various conditions: Effect of Temperature: In case of dyeing with disperse dye, temperature plays an important role. For the swelling of fibre, temperature above 100°C is required if high temperature dyeing method is applied. Again in case of carrier dyeing method, this swelling occurs at 85-90°C. In case of thermasol
- 3. dyeing method, if temperature is kept more, fabric is kept for less time in thermasol unit. Because in higher temperature, less time is enough for thermo fixation of dye. If it is kept for more time, then dye sublimation and loss of fabric strength may occur. Again though disperse dye is a water insoluble dye, its solubility increases with increasing temperature. Effect of PH: For disperse dyeing the dye bath should be acidic and pH should be in between 4.5-5.5. For maintaining this pH, generally acetic acid is used. We may also use any mineral acid like H3PO4. But those are strong and costly. So mild acid like acetic acid is used for controlling pH of the bath. At this pH dye exhaustion is satisfactory. During colour development, correct pH should be maintained otherwise fastness will be inferior and colour will be unstable. Effect of Time: During disperse dyeing, Time plays an important role. For perfect dyeing time is a must useful thing that should be maintained. If time is not maintained in disperse dyeing, there will be some problem such as- 1. Color shed will not be good 2. Dies will not absorb with fabric 3. Color fastness will not be good 4. The outcome of dyeing process will not be acceptable 5. Light fastness will not be good So it is important to maintain Time. In normal temperature method perfect dyeing time is 80-100 degree celsius ,and in high temperature method, time will be 105-140 degree Celsius. Conclusion: After having this discussion, we got to know about disperse dye and some conditions & their effects during disperse dyeing. --The End-- Submitted by Md Rakibul Hassan Id: 183014057