Batchwise Dyeing of Woven Cellulosic Fabrics: A Practical Guide | G. J. Parish, G. W. Madaras, and J. Shore

Contents

Preface
This further monograph in the Society of Dyers and Colourists’ series is intended to fill an outstanding gap in the literature covering the dyeing and finishing of cellulosic woven fabrics and blends.

In an attempt to present as complete a picture as possible, there is some overlap of topic from other publications and it became necessary to provide some additional background information on dyeing which in isolation could be regarded as beyond the scope of the title. Furthermore it is relevant to refer to fabric preparation including continuous techniques as these are regularly used prior to batch dyeing. The authors are of the opinion that to have left these subjects out would have created an unnecessary void.

It is also inevitable that in dealing with such a universally practised technology, certain process techniques, whilst internationally developed, are no longer universally applicable or acceptable in certain markets. The authors, mindful of some national or local restrictive legislation on chemical use and/or disposal, advise readers to be cautious in their interpretation of what were once, but may no longer be, acceptable practices.

Chapter 6 incorporates information on machinery for both preparation and dyeing. Some illustrations are included, but a comprehensive illustrative account already exists in Engineering in textile coloration, edited by C Duckworth and published by the Society. Reference to this publication is strongly recommended.

We acknowledge the help and advice received from several individuals and organisations, including the staff of the former Shirley Institute for their encouragement, to Ken Dickinson for helpful criticism and comment, and the several machine manufacturers who provided illustrations.

A special ‘thank you’ goes to Stuart Smith and his staff for editorial support and facilities in manuscript preparation.

CHAPTER 1
Economic background

1.1 INTRODUCTION
The stages to effect coloration of textiles are:

• Mass pigmentation
• Gel dyeing
• Tow dyeing
• Loose-stock dyeing
• Top dyeing
• Yarn dyeing
• Fabric dyeing: batch, pad-batch or continuous
• Garment dyeing.

During the conversion of fibres to yarns and fabrics, the coloration stage is determined by many factors, economics and fashion being the most important. This book is concerned with the batch dyeing of woven fabrics, an operation carried out after weaving, except for the special case of coloured woven designs. It is clearly desirable for the merchant converter or garment manufacturer to postpone the decision of coloration as long as possible in order to cater for the dictates of fashion, and fabric dyeing facilitates this.

Man-made fibres can be dyed at all the stages listed, whereas only stages (d) to (h) are suitable for natural fibres. Routes of coloration (a) to (e) have been discussed in an earlier book; likewise yarn dyeing and the dyeing of wool fabrics have been covered in previous titles. It is the intention here to extend the coverage of fabric dyeing specifically to cellulosics and blends in batchwise form.

In volume terms, gel, tow and loose-stock dyeing are most important, followed closely by yarn and fabric dyeing. Fabric dyeing will always claim a high percentage share of the output of the dyeing industry. Dyeing textiles in fabric or garment form offers the processor maximum flexibility in responding quickly to changes in fashion and market demand.

Fabric dyeing and finishing form an integral part of a sequence of operations in the conversion of cotton from fibre to saleable fabric or garment. Thus the dyer, printer or finisher occupies a position intermediate between weaving and making-up, and the dyeing and finishing industry therefore serves both the weaver and the garment manufacturer or maker-up.

In a truly vertically arranged company, where raw cotton bales enter at one end, and dyed and finished fabrics or garments leave at another, fabric dyeing and finishing form a link in a chain of operational steps. In some sectors the textile industry is horizontally organised, that is companies engage only in one major processing operation, be that spinning, weaving, dyeing, finishing or making-up.

The merchandise in whatever form is often owned by merchants, sometimes by large vertical companies, and the goods are sent to spinner, weaver, dyer and finisher to be processed on commission.

In general, the fastness requirements of a dyed fabric or article will vary according to the end use. A great deal of information is available concerning the properties and performance of dyed fabrics in different end uses and the large multiple retailers, vertical organisations and fibre manufacturers frequently have their own specifications which dyers and finishers are expected to meet.