Acid Dyes

Darshan Industries is one of the leading manufacturers & exporters of Acid Dyes.

Products

Acid Scarlet MOO

CI Name : Acid Red 73
CI No: 27290
CAS No : 5413-75-2
Acid Metanil Yellow

CI Name : Acid Yellow 36
CI No: 13065
CAS No : 587-98-4

Acid dyes are anionic organic dyes (containing sulfonate groups) that are used with organic cations such as alum to fix them to the surface of fibres.Acid dyes are highly water soluble and have better light fastness than basic dyes.The textile acid dyes are effective for protein fibres such as silk, wool, nylon and modified acrylics.Acid dyes, named for their application under acid conditions, are reasonably easy to apply, have a wide range of colours anddepending on dye selection, can have good colour fastness properties. The dyes are divided into three categories according to their levelling and fastness properties, namely levelling, milling and super milling dyes.

Molecular weights of acid dyes range from 200 to 900.

Chemical structure of acid dyes

These dyes are normally very complex in structure but have large aromatic molecules, having a sulphonyl or amino group which makes them soluble in water. Most of the acid dyes belongs to following three main structural molecules,

Anthraquinone type
Azo dye type
Triphenylmethane type

Molecular Chemistry of Acid Dyes

They contain sulphonic acid groups, which are usually present as sodium sulphonate salts. These increase solubility in water and give the dye molecules a negative charge. In an acidic solution, the -NH2 functionalities of the fibres are protonated to give a positive charge: -NH3+. This charge interacts with the negative dye charge, allowing the formation of ionic interactions. As well as this, Van-der-Waals bonds, dipolar bonds and hydrogen bonds are formed between dye and fibre. As a group, acid dyes can be divided into two sub-groups: acid-leveling or acid-milling.

Properties of Acid Dyes

Acid dyes combine with the fiber by hydrogen bonds, vanderwaals forces or through ionic linkages.
Acid dyes have no affinity for cotton cellulose’s, hence not suitable for cellulosics.
Acid dyes are anionic in nature.
Acid dyes are suitable for wool, silk, polyamide and modified acrylics.
Acid dyes applied from a strongly acidic to neutral pH bath.

Procedure of Acid Dyes

Dye bath set with

5-10% Anhydrous Glauber's Salt 2- 4% Sulphuric Acid (96%)
5-10% Anhydrous Glauber's Salt 2-4% Formic Acid (85%)
5-10% Anhydrous Glauber's Salt 2-4% Glacial Acetic Acid (40%)

Well dissolved dyestuff is added to one of the above-mentionedbaths (Depending on the chemical nature of the dye) while stirring.

The material is entered at about 50°C after running for five minutes temperature is raised gradually to boil and dyeing continued for 45- 60 minutes. If required 1-3% Sulphuric Acid is added after 45 minutes to complete the exhaustion.

Procedures

1:1
Metal complex dyes: These dyes exhibit good migration properties and have good light fastness and wet fastness properties.
Dye bath: 5 -10% Glauber's Salt, 4-5% Sulphuric Acid
Enter the goods at 60°C and raise temperature of the dye bath to boil dye for 90 minutes. Rinse and dry.

1:2
Metal complex dye: These dyes have excellent levelling properties, highlight fastness properties and used widely for combination shade because of excellent dyeing behaviour.
Dye bath : 1-3% Ammonium Sulphate (pH 6-6.5), 5-10% Glauber's Salt
Enter the goods at 50°C and rise the temperature of the dye bath to boile dye for 45- 60 minutes. Rinse and dry.

Darshan Industries – Manufacturer & Exporter of Acid Dyes

Since 1992 Darshan Industries is manufacturing Acid Dyes in its facility located in Ankleshwar. We manufacture acid dyes such as Acid Scarlet MOO & Acid Metanil Yellow. With limited product portfolio in Acid Dyes we have expertise for quality manufacturing with large facility of in Ankleshwar (Gujarat) India. Darshan Industries has already developed Acid dyes for application on leather, wool, nylon, silk etc.