2025
PRE-TREATMENT OF
TEXTILE
WANIA NAWAZ
BACHELORS IN TEXTILE ENGINEERING
NED UNIVERSITY OF ENGINEERING AND TECHNOLOGY |
,1|Page
Abstract
This document provides comprehensive, structured notes on Pre-treatment processes in textile
manufacturing, focusing on cotton and blended fabrics. It explains the sequence, purpose, and
mechanism of each key step—singeing, desizing, scouring, bleaching, and mercerization—
with relevant chemical formulations, machinery diagrams, and industrial conditions.
The notes are tailored for textile engineering students and include solved numerical examples,
viva questions, and MCQs with answer keys to support both theoretical understanding and
exam preparation.
Emphasis is also placed on eco-friendly techniques, safety standards, and modern
developments in pre-treatment. The clean formatting, bullet points, and visual aids ensure ease
of learning and quick revision.
,2|Page
Table of Contents
1. Introduction - page no 3
2. Pre-treatment machinery - page no 16
3. Singeing - page no 34
4. Desizing - page no 48
5A. Scouring of cotton - page no 56
5B. Scouring of wool - page no 62
5C. Scouring of silk - page no 68
6. Bleaching - page no 75
7. Optical Brightening Agents - page no 85
8. Mercerization - page no 91
9. Heat Setting - page no 99
, 3|Page
CHAPTER 1 ( INTRODUCTION )
1. Main Objectives of Pretreatment
Pretreatment (also called preparation) readies textile fabrics for subsequent dyeing, printing, or finishing
operations. Its primary objectives are:
• Removal of Impurities: Eliminate all natural, added, and processing residues (e.g., waxes, oils,
pectins, suint, sericin, sizing agents, dust, dirt) so that the fabric readily and uniformly absorbs
dyes or chemicals.
• Improvement of Wetting and Absorbency: Ensure fibers become fully wetted by water and dye
liquor, avoiding uneven dye uptake or “barre.”
• Stabilization of Fabric Structure: Relax residual tensions (e.g., from weaving or knitting),
allowing uniform shrinkage before dyeing/finishing.
• Enhancement of Quality and Hand: Produce a fabric surface that is clean, soft, and free from
residual stiffening, which leads to better feel (hand) and appearance.
PRE-TREATMENT OF
TEXTILE
WANIA NAWAZ
BACHELORS IN TEXTILE ENGINEERING
NED UNIVERSITY OF ENGINEERING AND TECHNOLOGY |
,1|Page
Abstract
This document provides comprehensive, structured notes on Pre-treatment processes in textile
manufacturing, focusing on cotton and blended fabrics. It explains the sequence, purpose, and
mechanism of each key step—singeing, desizing, scouring, bleaching, and mercerization—
with relevant chemical formulations, machinery diagrams, and industrial conditions.
The notes are tailored for textile engineering students and include solved numerical examples,
viva questions, and MCQs with answer keys to support both theoretical understanding and
exam preparation.
Emphasis is also placed on eco-friendly techniques, safety standards, and modern
developments in pre-treatment. The clean formatting, bullet points, and visual aids ensure ease
of learning and quick revision.
,2|Page
Table of Contents
1. Introduction - page no 3
2. Pre-treatment machinery - page no 16
3. Singeing - page no 34
4. Desizing - page no 48
5A. Scouring of cotton - page no 56
5B. Scouring of wool - page no 62
5C. Scouring of silk - page no 68
6. Bleaching - page no 75
7. Optical Brightening Agents - page no 85
8. Mercerization - page no 91
9. Heat Setting - page no 99
, 3|Page
CHAPTER 1 ( INTRODUCTION )
1. Main Objectives of Pretreatment
Pretreatment (also called preparation) readies textile fabrics for subsequent dyeing, printing, or finishing
operations. Its primary objectives are:
• Removal of Impurities: Eliminate all natural, added, and processing residues (e.g., waxes, oils,
pectins, suint, sericin, sizing agents, dust, dirt) so that the fabric readily and uniformly absorbs
dyes or chemicals.
• Improvement of Wetting and Absorbency: Ensure fibers become fully wetted by water and dye
liquor, avoiding uneven dye uptake or “barre.”
• Stabilization of Fabric Structure: Relax residual tensions (e.g., from weaving or knitting),
allowing uniform shrinkage before dyeing/finishing.
• Enhancement of Quality and Hand: Produce a fabric surface that is clean, soft, and free from
residual stiffening, which leads to better feel (hand) and appearance.
