The application of acid dyes with protein materials results inside an ionic or salt link involving the dye molecule as well as the fibre polymer. The point of the fibre polymer where the dye is connected is termed the dye site. In wool, the dye websites are of countless amino group of the fibre. Under dyeing conditions, the amino group becomes certainly charged plus attracts the negatively charged dye anion.
There are a big quantity of amino groups are present inside the wool fibre. As a guide, there are around twenty occasions because numerous amino groups about wool because about nylon plus five instances because numerous amino groups about wool because about silk. Dark shades is commonly be obtained about wool as a result of the very amorphous nature of the fibre, that results inside fairly convenient penetration of the fibre polymer by the dye molecule plus as a result of the presence of minor groups.
Method of dyeing with acid dyes on NYLON
The dyeing attributes of acid dyes for nylon plus wool are synonymous. The shades are pretty synonymous with the related hues about wool, yet the saturation point is lower with nylon. Whenever the pH of the dye answer is 2 or lower, nylon has greatly improved affinity for acid dyes. In practice, dyeing can not be carried out inside the pH area of 2 with 2.5 considering the degradation of the nylon will be excessive.
Acid dyes requiring sturdy acid are used from a dye liquor containing 3 with 5% of formic acid. Sulphuric acid cannot be selected considering it could result degradation of thenylon, as well as the addition of Glauber‟s salt is omitted considering it has no beneficial impact. Non-ionic leveling agent, either alone or mixed with cationic items, are utilized. The goods are entered cold as well as the dye shower is brought with the boil plus dyeing continued at this temperature for ¾ with 1 hr. With these acid dyes fatigue happens perfectly with weaker acid, 1 with 3% acetic acid (80%), can be substituted for the formic acid or, alternatively, 1 with 3% of ammonium acetate can be selected.
The application of acid dyes with nylon additionally results inside ionic bonds or salt hyperlinks involving the dye molecules as well as the polymer. The point where the ionic is created is the terminal amino groups of nylon. The better crystalline fibre structure of nylon compared with wool in addition to the fairly lower amount of amino groups signifies which dark shades about nylon can not be obtained with acid dyes.
Application of Acid dyes on silk
Although silk has an affinity for acid dyes the hues are less quick than about wool. Silk usually exert its affinity for acid dyes at lower temperature than is the case with wool, plus dyeing is generally commenced at 40ºC as well as the temperature is not enabled with rise above 85ºC. Glauber‟s salt is not right for utilize with silk because it diminishes its luster. Sulfuric acid damages the silk. Acid utilized ought to be acetic acid. While utilizing boiled off liquor the shower need to be neutral or just faintly acidic.