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Defects of Sulfur Dyeing Part 3

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Defects of Sulfur Dyeing Part 3

October 29, 2017 MH Tomal

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MH Tomal

Author at Textile Study Center

Internship Trainee at SQUARE Fashions Ltd. Studied at Bangladesh University of Textiles Studied at Notre Dame College, Dhaka Studied at Dhaka Residential Model College

Latest posts by MH Tomal (see all)

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Part 01 :Introduction to Sulfur Dyes | History of Sulfur Dyes | Method of manufacture of Sulfur dye | Trade Names of Sulfur Dyes | Characteristics of Sulfur Dyes | Features of Sulfur Dye | Chemical Structure of Sulfur Dye | Chemical Nature of Sulfur Dyes | Chemistry of dyeing with Sulfur Dye

Part 02 :Classification of Sulpher Dyes | Sulfur dyeing methods | oxidizing and reducing agent for sulfur dyeing | Reducing Steps of Sulfur Dyes |Oxidation Step of Sulfur Dye| Dyeing of Cellulosic Fibres with Sulfur Dyes |Typical Recipe for sulfur dyeing | Good Preparation for sulfur dyeing | Dye solution preparation or Reducing Step for sulfur dyeing | Dyeing with sulfur dye |Oxidation of sulfur dye |After treatment for sulfur dye | Precaution in the sulfur dyeing process|Control of Dyeing for sulphar dye | Topping of Sulpher Dyes |Improving of Fastness Properties of sulfur dye

Defects of sulfur Dyeing :

They are mainly two defects which are common in sulfur dyed textile materials:-

Bronziness or Dullness of shades
sulfur Black tendering

Now they are Described below:-

Bronziness of Shades :

This is a common defect found in sulfur dyed textile materials.

Causes:

The causes are as below:-

Excessive delay between lifting of the material from the dye bath and washing off.
Exposure of goods to air while dyeing.
Too much use of common salts as exhausting agents.
Insufficient Na₂S (i.e. reducing agent) in dye bath. As a result of which dye is incompletely reduced.
Strong dye liquor in the dye bath.

Remedies:

The remedies are as below:-

Good washing and dilute solution of Na₂S (0.1%) at 30⁰C or,
A treatment with boiling soap solution or a strong Na₂S solution or,
A treatment with a solution containing 10% salponified palm oil at 60⁰C or,
a) Ammonia : 125-200 gm/100 litre or, 1.25-2 gm/litre

T.R Oil : 200-300gm/100litre or, 2-3 gm/litre.

Time : 15 minutes

Temperature : Water Bath

Or,

b) Olive Oil soap : 2-5 lbs/100 Gallon

Olive Oil : 1-2 lbs/100 Gallon

Soda Ash : 1-2 lbs/100 Gallon

Time : 15-30 minutes

Temperature : 60⁰C

Sulfur Black Tendering:

If sulfur dyed textile materials are stored (weakening) tentering effect is seen on the cellulose. Due to storage a part of the sulfur colour converts in to H₂SO₄ by oxidizing which in turn causes degradation of cotton by hydrolysis. It is a serious problem of sulfur dyed goods.

Causes:

The causes are as below:-

Gradual oxidation of sulfur to H₂SO₄on storage.
After treatment with copper salts causes rapid tendering.
Presence of iron as an impurity causes rapid tendering.
The method of oxidation for the recon version to insoluble form influence tendering.

Remedies:

The remedies are as below:-

Treatment of dyed material with 1-3% K₂Cr₂O₇ and 1-3% CH₃COOH at 60⁰C temperature for 30 minutes followed by through rinsing.
Treatment with a little CH₃COOH so that H₂SO₄may be converted in to harmless acetic acid.
Using 5 gm/litre soda ash after dyeing followed by drying without rinsing.

Stripping of Sulfur dyes:

Unevenly Dyed shades on cellulosic materials with sulfur dyes may be corrected by a treatment with a worm solution of Na₂S in the presence of Albigen A (polyvinyl pyrolodine)

If this method is found to be in effective then the uneven dyed material may be treated with a solution of a NaOCl or bleaching powder (2-3 gm/Litre of available chlorine).

In some cases bleaching with KMnO₄ solution may be effectively carried out. In other cases the dyed material may be treated with worm NaOCl solution in the presence of NaOH.

The uneven dyeing of material causes due to the following reasons:-

The oxidation of dye during dyeing when the material comes in contact with air.
Presence of gummy material on the fabric.
Defective Dye.

Uses of Sulfur Dye:

To dye Umbrella cloth with sulfur black.
To dye cotton fabric eg-lining boot.
To dye rubber material hence after treatment by CuSO₄ is necessary

S-Radical in Sulfur dye:

In case of tendering of sulfur, due to storage lose of strength occurs and forms to sulfur radical. Three types of sulfur radical are present in sulfur dyes as below:-

Mechanically free sulfur : Air+S= H₂SO₄
Stable sulfur: 70%-80%, not easily oxidized.
Chemically active sulfur : 20-25%

Colors/Shades found from Sulfur dyes:

Red : not good, not pure red color.
Black, blue, brown : Excellent Shade.
Others : Olive, Orange, green etc.

Causes for the Popularity of Producing Black Shades with Sulfur Dyes:

Low cost
Fair to good light fastness
High Wash fastness
Easy to apply
Low energy required
Chemical resistance is moderate to good.
Wide range of shades especially on heavy, durable shades on apparel fabric.

Comparison between Sulfur & Vat Dyes:

*Subject*	*Sulfur Dye*	*Vat Dye*
1. Molecular Size	1. Dye molecules are very Large	1. Smaller than Sulfur
2. Shade	2. Gives dull shade due to varying conditions	2. Gives bright shades
3. After reduction	3. Smaller size molecules are obtained D–S–S–D+[H] à D–SH + SH–D	3. Vat dyes are reduced as below Save
4. Fabric Dyed	4. Cotton, Rayon, Nylon & P/C	4. Cellulose Rayon etc
5. Hydrolysis	5. Under high temperature and Humidity	5. Susceptible to hydrolysis i.e. easy to Hydrolysis.
6. Wash Fastness	6. Good to very good	6. Excellent
7. Price	7. Cheaper than Vat dye	7. Very costly dye
8. Light fastness	8. Good to very good	8. Excellent for anthraquinone.
10. *Sulfur* linkage	9. Contain *Sulfur* linkage	9. No *Sulfur* linkage is present.
10. Ionization	10. The dye molecules are negatively ionized after reduction	10. Same

Reasons for why so called:

The dyes are so called as they contain sulfur linkage within their molecules but dissolved in a solution of sulphide which acts as a reducing agent, breaking the sulfur linkage and converting the molecules into simpler components Water insoluble sulfur dye molecule)which are soluble in water and substantive towards cellulose.

Dye–S–S–Dye

Reference

Broadbent A D 2001 Basic principles of textile coloration Society of Dyers and Colourists p 566
Shenai V A Chemistry of Dyes and Principles of dyeing
Carr C M 1995 Chemistry of the Textiles Industry (Dordrecht: Springer Netherlands)
Chakraborty J N Fundamentals and Practices in Colouration of Textiles
John Wiley & Sons Inc 2000 Kirk-Othmer Encyclopedia of Chemical Technology (Hoboken, NJ, USA: John Wiley & Sons, Inc.)
Ühnel G E R D K, Aktiengesellschaft B, Olff J O W, Ag B, Uppert G Ü R, Aktiengesellschaft B, Chmitt M I S, Aktiengesellschaft B, Etired C H H E I D R, Ag C, Etired M A X H Ü R, Aktiengesellschaft H, Etired H E L E R and Aktiengesellschaft B 2016 Textile Dyeing , 2 . Dyeing of Cellulose Fibers 1–27
Hunger K 2003 Industrial Dyes: Chemistry, Properties, Applications
Rahman M M Wet Processing 1
Iqbal M 2008 Textile Dyes 167
ARNOLD R. LANG DYES AND PIGMENTS: NEW RESEARCH

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MH Tomal

Author at Textile Study Center

Internship Trainee at SQUARE Fashions Ltd. Studied at Bangladesh University of Textiles Studied at Notre Dame College, Dhaka Studied at Dhaka Residential Model College