Quality evaluation of bleached, dyed and printed textiles

R.B.CHAVAN

Department of Textile Technology

Indian Institute of Technology

Hauz-Khas, New Delhi 110016

E-mail: rbchavan@hotmail.com

Identification of fibres

Burning test

Fibre Burning behaviour

Cotton Burn with continuous flame, smell burning paper

Wool Does not burn, smell burning hair, balck char

Silk Does not burn, rotten smell

Nylon Does not burn, melt, white hard bid

Polyester Does not burn, melt, white hard bid

Acrylic Burn, no melting, black char

Solubility test

Fibre Solvent

Cotton Cuprammonium hydroxide, cadoxene

Wool 5% NaOH, boil

Silk Saturated zinc chloride

Polyester Ortho chloro phenol (OCP)

Nylon Formic acid

Acrylic Dimethyl formamide (DMF)

Desizing enzyme activity

1. Rate of disappearance of blue colour of stach iodide solution

2. Rate of decrease in viscosity of starch solution

Desizing efficiency

Qualitatative

1. Staining with starch iodide solution of desized fabric

Quantitative

1. Determination of weight of sized and desized fabric of same dimensions

2. Quantitative estimation of residual starch on desized fabric.

Scouring efficiency

1. Time required for absorption of a drop of water on scoured fabric ( 3 seconds)

2. Sinking test (Yarn, Fabric)

Bleaching efficiency

1. Whiteness of bleached fabric (% reflection of light 70%)

Fibre degradation during scouring and bleaching

1. Carboxyl group estimation (Methylene Blue absorption)

2. Estimation of Aldehyde groups (Copper Number)

3. Loss in strength of fabric (Tensile strength)

Dyeing and printing

Colour strength of commercial dye

1. Comparison of dyeing of standard dye sample and test sample

2. Measurement of optical density of same concentration of standard and test dye sample

Fastness properties

1. Wash fastness

2. Light fastness

3. Rubbing fastness (Crock fastness)

4. Perspiration fastness

5. Fastness to chlorine

Fastness property evaluation

Grey scale

1. Grey scale for colour change

2. Grey scale for staining

Fastness grades

1-5 for all except light fastness

Grade 1 Poor

Grade 5 Best

Light fastness grade 1-8

Grade 1 poor, Grade 8 best

Blue wool standards from grade 1-8 essential for exposure of samples to light

Laboratory facilities

1. Spectrophotometer

2. Digital balance with accuracy upto three decimals

3. Fade-o-meter for light fastness

4. Landero-meter for wash fastness

5. Crock meter for rubbing fastness

6. Perspiro-meter for perspiration fasness

7. Tesnsile strength tester

8. Abrasion tester

9. Stiffness tester

10.Crease recovery angle tester

11.Pilling tester

12.Abrasion tester

Environment related parameters

1. Estimation of banned amine on dyed sample

Principle

Reduction of dye from dyed or printed sample with sodiun hydrosulphite and casutic soda under standard conditions. Estimation of liberated amine using

HPLC Or

GC-mass spectrometer

Comparison of peaks with standard amines

List of banned amines

Amine 1-4 Carcinogenic to human

Amine 5-20 Carcinogenic to animals

Mechanism of dye degradation in human body

Metal Estimation

Cr, Cu, Hg etc

Instrument used

Atomic abasorption spectrometer