Dyeing presentation

Dyeing presentation

• 1.
  By: Presented by :Ms.K.Kathiroli Asst Prof Dept of fashion technology and costume designing Bon secours college for women – Thanjavur .
• 2.
   * Dyeingis the process of adding color to the textile products like fibers, yarn and fabrics.  * The temperature and time controlling are main key factors in dyeing.  * A dye is a color substance that has a affinity to substrate to which is being applied.  * Both dyes and pigments appear to be colored because they absorb some wavelength of light more than others.
• 3.
   Dyeing isthe application of dyes or pigments on textile materials such as fibers, yarns, and fabrics with the goal of achieving color with desired color fastness. Dyeing is normally done in a special solution containing dyes and particular chemical material. Dye molecules are fixed to the fiber by absorption, diffusion, or bonding with temperature and time being key controlling factors. The bond between dye molecule and fiber may be strong or weak, depending on the dye used.
• 4.
   1.Acid  2.Basic 3.Disperse  4.Reactive  5.Sulphur  6.Azoic  7.Direct  8.Vat  9. Modrant  10.Solvent
• 5.
   *Natural dyes *Synthetic dyes
• 7.
   * Majorityof the natural dyes are from plant sources – bark, berries, roots, leaves, wood and fungi.  * Throughout history, people have dyed their textile using common and locally availabe materials.  * The discovery of man-made synthetic dyes late in 19th century ended large –scale market for natural dyes.
• 8.
   * Thefirst human – made organic dye, mauveine, was discovery serendipity by William Henry Perkin in 1856.  * Synthetic dyes quickly replaced the traditional natural dyes.  * The cost less , they offered a vast range of new colors , and they imparted better properties to the dyes materials.
• 10.
   Vat dyesare a class of dyes that are classified as such because of the method by which they are applied.  Vat dyeing is a process that refers to dyeing that takes place in a bucket or vat. Almost any dye, including fiber-reactive dyes, direct dyes, and acid dyes, can be used in a vat dye.  Cotton, wool, leather and other fibers can be all dyed with vat dyes. The original vat dye is indigo, once obtained from plants but now produced synthetically.
• 11.
   In areactive dye, a chromophore (an atom or group whose presence is responsible for the color of a compound) contains a substituent that reacts with the substrate.  Reactive dyes have good fastness properties owing to the covalent bonding that occurs during dyeing.  Reactive dyes are most commonly used in dyeing of cellulose like cotton or flax, but also wool is dyeable with reactive dyes. Reactive dyeing is the most important method for the coloration of cellulosic fibers.  Reactive dyes can also be applied on wool and nylon; in the latter case they are applied under weakly acidic conditions.
• 12.
   * Incontrast to direct dyes, wool and leather goods are dyed by the process of ion exchange, exploiting the cationic nature of proteins near neutral PH. The development of substantive dyes helped make mordant dyes obsolete. * A substantive dye or direct dye is a dye that adheres to its substrate, typically a textile, by non- ionic forces.
• 13.
   Azoic dyesare organic compounds bearing the functional group R−N=N−R′, in which R and R′ are usually aryl. They are a commercially important family of azoic compounds, i.e. compounds containing the linkage C-N=N-C.  Azoic dyes are widely used to treat textiles, leather articles, and some foods. Chemically related to azoic dyes are azoicpigments, which are insoluble in water and other solvents
• 14.
   Sulpur dyesare the most commonly used dyes manufactured for cotton in terms of volume.  They are inexpensive, generally have good wash-fastness, and are easy to apply.  Sulfur dyes are predominantly black, brown, and dark blue.  Red sulfur dyes are unknown, although a pink or lighter scarlet color is available.
• 15.
   Acid dyesare usually sodium salts of sulphonic acids and a few of them are sodium salts of carboxylic group.  These dyes are mainly used for protein and polyamide fibers.  Acid dyes posses direct affinity for wool, silk, nylon, regenerated and protein fibres.  An acid dye is a dye that is typically applied to a textile at low PH . They are mainly used to dye wool, not cotton fabrics.  Some acid dyes are used as food colorants.
• 16.
   These aresoluble in water with little addotion of acetic acid. Basic dyes produce most brilliant shades.  they have direct affinity for wool and silk but not for cotton.