Tuesday, 28 April 2015

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Acid Dye

Acid Dye

Acid Dye
Acid Dye
The acid dyes are vast colors containing one or more sulfonic or carboxylic acid salt useful gatherings. These colors are colored onto filaments from acid solution, since positive charge improvement inside the fiber in acid solution goes about as a main impetus for color dissemination and movement into the fiber. Just filaments which add to a positive charge in the vicinity of acid, for example, fleece, silk, and other protein filaments, nylon, and certain adjusted synthetics, are promptly colored by Acid dyes, acid dyes on filaments or fibers are sensibly colorfast to light and washing, however mordanting (more complete insolubilization of the color through response with a metal salt) will enhance the general speed properties of the color. The shading of the color may be influenced to a degree by mordanting; nonetheless, premetallized acid colors are a unique class of acid dyes which have been responded wi th a stringent preceding coloring and which have sufficient solvency to be colored under conditions typically utilized for acid dyes.

Chemical structure of acid dyes:

These dyes are regularly extremely complex in structure yet have extensive fragrant particles, having a sulphonyl or amino gathering which makes them solvent in water. A large portion of the acid dyes has a place with taking after three principle basic particles,

1.Anthraquinon sort
2.Azo dye sort
3.Triphenylmethane sort.

Distinctive sorts of acid dyes 

The essential dyes are grouped into a few gatherings , in view of the leveling properties, economy of the dyeing and quickness properties, however for the most part these are ordered into these three classes,

1.Neutral acid dyes

These are supra processing or fast acid dyes, having medium to great wet speed properties , a percentage of the dyes have poor light quickness in pale shades . large portions of the dyes are utilized as self shades just. These are connected to the fiber in a feebly acid or nonpartisan pH.

2.Weak acid dyes 
These dyes fits in with the processing class of dyes. These dyes have great quickness properties however light speed is moderate to poor.

3.Strong acid dyes
These dyes are connected in a firmly acidic medium furthermore called leveling dyes, however there wet speed properties is a confinement. These dyes are great to create the blend shades.

Arrangement as indicated by dyeing attributes

Acid dyes are generally characterized by dyeing conduct, particularly in connection to the dyeing pH, their movement capacity amid dyeing and their washing speed. The sub-atomic weight and the level of sulphonation of the dye particle focus these dyeing attributes. The first grouping of this sort, taking into account their conduct in wool dyeing, is as per the following:

(1) Level dyeing or balancing acid dyes;

(2) Fast acid dyes;

(3) Processing acid dyes;

(4) Super-processing acid dyes.

Processing is the methodology in which a woolen material is dealt with, in pitifully basic arrangement, with significant mechanical activity to advance felting. Dyes of good speed to processing are key to stay away from shading draining amid the methodology.

Properties of acid dyes

The fundamental properties of acid dyes are:

Since these are sold as a sodium salt, there fore these structure a vast anion in the watery medium. 1.Th acid dyes are anionic in nature.
2.The acid dyes are suitable for wool, silk, polyamide and adjusted acrylics.
3.The acid dyes connected from an unequivocally acidic to nonpartisan pH shower.
4.The acid dyes have no partiality for cotton cellulose's , consequently not suitable for cellulosics.
5.These dyes join with the fiber by hydrogen bonds , vander waals strengths or through ionic linkages.

Instrument of dyeing with acid dyes

Disintegration of dyes in fluid dissolvable, produces a hued anion, 

The protein and polyamide filaments produce cationic locales in water under acidic conditions, as the acidity of the arrangement is expanded more cationic destinations are delivered under these firmly acidic conditions. These cationic locales are subsequently accessible for the acid dye anions to join with through hydrogen holding, vander waals powers or ionic holding. These linkages are sufficiently solid to break , and hence dyeing delivered are quick .

On Wool 

Electrolyte in the acid dye bath goes about as an impeding operators due to chlorides particles pulled in by the positive destinations at the fiber and in the opposition between. Expansion of acid goes about as a n depleting operators , in light of the fact that unequivocally acidic conditions makes more cationic locales accessible and in this manner accessible dye anions got joined with these.

Dyeing temperature 


The dyeing is by and large done at bubbling temperature for 30- 60 minutes relying on the profundity of the shade and dyestuffs utilized.

Dyeing leveling operators
For the situation dyeing with acid dyes , mostly cationic operators, for example, ethoxylated greasy amines are utilized as leveling specialists.

Warming rates
Warming rate is by and large kept 1-30C/Min
Washing off procedure
A regular dyeing cycle of nylon fiber dyeing with acid dyes is demonstrated in the above outline,
Wool dyeing technique with acid dyes.

Fastness properties of acid dyes
The wet and light quickness properties of the acid dyes changes from poor to brilliant , relying on the sub-atomic structure of the dyes.

The quickness properties according to the classification are as per the following

Impartial acid dyes:-following these dyes have great leveling and relocation properties ,and have a low proclivity for the fiber, accordingly the wet quickness properties of this class are by and large poor.
Powerless acid dyes or half processing dyes :- These dyes have a medium to great natural inclination for the fiber and are by and large connected in a pitifully acidic shower, shows medium to great wet speed properties. Solid acid dyes or super processing dyes :- These dyes have poor fatigue properties, in this way connected under exceptionally solid acidic condition , display great quickness properties.

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