Dye class identification on fibres,

Iidentification of Dye class on fibres

Dye class identification is very important test to select a relevant dye for particular fibre or fabric. All kinds  dyes are not suitable for all textile fibres. For example Reactive dyes are confidently identified for natural cellulose fibres, because it is possible to associate the reactive dyes structure with the cellulose fibre structure.  If the fibre material is unknown, Fibre identification should be carried out first.

   Dye class identification for various fibres

The most well-known dye class identification systems on fibres are:

I. Krefeld method:

 a) For cellulose fibres (cotton, silk, jute etc): dissolve fibre sample in suitable solvent, sulphur test (for sulphur-based dyes), blind vat (oxidation and cationic dyes), stripping and staining reactions (for mordant, acid, direct and diazo dyes), dimethyl formamide test (for reactive dyes), glacial acetic acid test (for vat, naphthol and phthalocyanine dyes).

b) For animal fibres (wool): paraffin test, blind vat and reoxidation (for vat and naphthol dyes), detection of metals (metal complex and chrome dyes), cold glacial acetic acid (cationic dyes), suitable solvent (reactive, acid and direct dyes).

c) For synthetic fibres: a caprolactam melt is prepared or stripping by means of glacial acetic acid carried out. The melt and the solution are mixed with ether and processed further. Dye classes which can be identified are disperse, metal complex, chrome, acid, cationic and naphthol dyes.

II. Reutlinger method:

a) For cellulosic fibres: water, wash, paraffin, pyridine, glacial acetic acid, hydrogen sulphide, chlorine, benzene tests and blind vat.

b) For animal fibres: water, wash, paraffin, glacial ace tic acid, ammonia, pyridine, benzene tests and blind vat.

c) For synthetic fibres: Acetate, Polyamide and Acrylic dyes.

III. In accordance with the AATCC guidelines for cellulosic, animal and synthetic fibres.

Dye classification:

A distinction is made between the following methods of classification:

I. Scientific classification of dyes based on their chemical structure, e.g. anthraquinone, azo dyes, etc.

II. Technical classification of dyes based on their dyeing properties, e.g. direct, acid, wool dyes, etc.

III. Commercial classification of dyes based on various aspects according to the manufacturer, e.g. according to fastness properties such as Sirius Light, Indanthren, etc. or according to the method of dyeing under collective names, e.g. Remazol = reactive dyes (Dystar), Palanil = disperse dyes (BASF), etc.

Wish you good luck-------------------------------------------
You Should read more related post to gain more knowldge.