Bechtold / Pham Textile Chemistry

2. Revised and Extended Auflage 2023
ISBN: 978-3-11-079577-6
Verlag: De Gruyter
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 491 Seiten

Reihe: De Gruyter STEM

Textile and fibre chemistry form the theoretical basis to understand production and properties of textile based products. In this 2 edition fundamentals of textile chemistry and theoretical and applicatory aspects of colour chemistry are interconnected to draw detailed picture of chemical reactions occurring during production and modification of textile products. An overview about chemical modification, finishing operations is given to explain how to impart special functionalities into functional products. Examples for technical scale processes and representative machinery used therein give insight into the technical reality of a dyehouse. A new chapter about circularity of textiles highlights the interlinkage between product design, including dyes and finishes, and the requirements to develop future fibre-to-fibre recycling.

The work covers all relevant aspects of a textile product from fibre production, coloration, finishing, consumer use and fibre-to-fibre recycling. The content of the book allows a first entry into this multi-disciplinary field. Through its comprehensive character the authors explain the interdependence between textile and fibre processing and aspects of recycling, which makes the work a valuable source of information to design future textiles for circularity.

Zielgruppe

Researchers/students in chemistry, industrial chemistry, chemical

Autoren/Hrsg.

Bechtold, Thomas

Pham, Tung

Fachgebiete

• Naturwissenschaften Chemie Organische Chemie
• Technische Wissenschaften Maschinenbau | Werkstoffkunde Technische Mechanik | Werkstoffkunde
• Technische Wissenschaften Verfahrenstechnik | Chemieingenieurwesen | Biotechnologie Technologie der Textilverarbeitung und Faserverarbeitung
• Naturwissenschaften Chemie Physikalische Chemie

Leseproben

1 Textiles

1.1 Introduction

The architecture of a textile structure is a result of a combination of several production stages. The respective stage of production determines the principles of applicable textile chemical operations and also defines the final result. Application of some chemical treatment, for example, a colouration step, will lead to a completely different result when applied at the level of fibres or fabric.

This explains various properties and appearances of textile products, which also helps in continuous progress in the design of new products and exploring new properties. Examples of different levels of textile chemical modifications are summarised in Table 1.1.

Table 1.1:Relevant stages in textile processing, materials and processes, relevant characteristic properties and examples for products.

Stage	Material/process	Characteristic properties	Example

Spinning

Fibre formation

Native, synthetic polymers

Chemical reactivity, physical properties

Cellulose, polyester

Thread formation

Filament production, staple fibre spinning

Longitudinal structure

Yarn, ply, wrapped yarn

Fabric formation

Weaving, knitting, nonwovens

Physical properties, accessibility

Plain weave, twill, satin, single jersey, fleece, web

Embroidery

Pattern formation

Localised modifications

Tailored fibre placement, conductive lines

Textile chemical modification

Dyeing, printing, finishing

Possible at every stage of production

Chemical, physical properties, surface modification

Coloration, pattern formation, antimicrobial properties, coating

Garment production

Assembly of material to a final product, sewing, taping

Final form and functionality

Clothing, technical products, tents, sails

In Table 1.1 various stages of textile processing and the materials are listed along the production chain. Each stage contributes to the development of characteristic properties, which are dependent on the choice of material, the combination of production steps and conditions.

Based on the stage where a textile chemical treatment is to be installed, the basic methodology and theoretical background as well as the technical equipment will differ.

With the rise of technical textiles, the scope of treatment and the field of applications for textile products have widened further. New techniques to obtain specialised properties, for example, electrical conductivity, surface modification by plasma or specific barrier properties through coating were introduced in textile chemical operations.

An almost endless number of variations and combinations of material and processing steps make a straight ordering and arrangement of textile chemical steps impossible; thus in this chapter, definitions of important textile technical terms and techniques are given to formulate a basic set of fundamental terms that will be useful for the other chapters.

1.2 Spinning

With the exception of silk, all other natural fibres that are of technical relevance are obtained in the form of staple fibres. Staple fibres exhibit a characteristic average length. In the spinning process, fibres are entangled, for example, by rotation, to increase the friction between the individual fibres and thus build a staple fibre yarn.

Different techniques are used to introduce the required number of turns per length into a spun yarn: ring spinning, open-end spinning, friction spinning and air-jet spinning. The characteristics of a yarn will depend on the spinning technology used. This will also influence the outcome of textile chemical operations as accessibility for chemicals will depend on the physical structure of a yarn (e.g., fineness of fibres, yarn count and number of turns per metre).

Synthetic fibres are fabricated as continuous filament fibres, namely, cables. The primary product of a fibre-spinning process is the endless fibre, the filament that, for example, has been obtained through melt extrusion. In rare cases, a single filament, the so-called monofilament, is the final product, which, for example, could be a string for a guitar or a fishing line. When several filaments are produced at the same spinneret, a multifilament is formed. A multifilament yarn, for example, is used to knit tights. For reasons of productivity, a very high number of holes are built in the same spinneret, which then result in a high number of filament yarns, forming a tow. The tow is then cut to staple fibres or is torn in a converter to deliver staple fibres.

Staple fibres are processed to yarns using similar procedure as that for natural fibres. At the stage of fibre spinning, fibre blends can also be formed; these blends are called intimate blends, for example, cotton/polyester (50/50) and cotton/polyamide (40/60).

When two or more yarns are wound together, a ply is formed. When different materials are wound together, another level of material blending is realised.

Core–spun yarns consist of two material layers. The core forms the inner layer, for example, highly elastic polyurethane filament yarn, which then is wrapped with another material, for example, polyamide fibres, to cover the core material. In the given case, the core material is responsible for the high elasticity of the yarn, while the outer layer is required to achieve dyeability of the yarn.

1.3 Linear density – yarn count

A characteristic measure to classify fibres and yarns is given by the linear density, which defines the mass of polymer per length of fibre or yarn [1]. Different systems for linear densities are in use; their use depends on the material and region.

Tex system (Tt): In the tex system, the mass of fibre, yarn in grams per 1,000 m length of fibre, yarn is considered (eq. (1.1)). A yarn count of 1 tex corresponds to a mass of 1 g of material for a yarn length of 1,000 m. Thus in the tex system, the reference length l = 1,000 m. One kilometre of a yarn with 20 tex yarn count will exhibit a mass of 20 g.

(1.1) Tt=ml(units: tex,g/1,000 m)

For fibres the subunit dtex is often used, which then represents the mass of fibre in grams, which is obtained by a length of 10,000 m of fibres.

Metrical number (Nm): An older but still widely used unit is the metrical number (Nm), which considers the length of a fibre, yarn that is obtained by 1 g of fibres, namely, yarn (eq. (1.2)). The unit of the yarn count in Nm thus is metre per gram. Thus, one gam of a yarn with Nm 20 will exhibit a length of 20 m:

(1.2)Nm=lm(units: m/g)

For filament yarns, still an older system is quite often used, the French denier (D). Similar to the Tt system, this count considers the mass of material per reference length; however, the sampling length in the case of the denier system is 9,000 m (eq. (1.3)). Thus, a fibre with a count of 1.3 denier will exhibit a mass of 1.3 g for a length of 9,000 m.

(1.3)D=ml(units: g/9,000 m)

There are still a number of other systems in use to describe the linear density, for example, the Number English (Ne), which relates the mass to a certain defined length.

1.4 Fabric formation

Different techniques are in use to produce plain textile structures. Main techniques are summarised in Table 1.2.

Table 1.2:Main techniques in textile fabric formation.

Technique	Characteristics of formation	Examples

Weaving

Rectangular crossing of warp and weft yarn

Plain weave Twill Satin/atlas

...

Über Autor(innen)

Prof. Dr. Thomas Bechtold, University Innsbruck, Research Institute for Textile Chemistry and Textile Physics.
Prof. Bechtold is the head of the Research Institute for Textile Chemistry and Textile Physics at the University of Innsbruck since 1998. He is one of the leading scientist in the field of fabric and textile chemistry and published over 260 articles/chapters and 20 patents. Prof. Bechtold is involved in several collaborations with industry and interdisciplinary research programmes. In 2015 he was awarded with the „Wissenschaftspreis des Landes Vorarlberg“ in Austria.

Prof. Dr.-Ing. Tung Pham, University Innsbruck, Research Institute for Textile Chemistry and Textile Physics. Prof. Tung Pham is working as industrial research professor at the Research Institute for Textile Chemistry and Textile Physics at the University of Innsbruck since 2016. He obtained his Ph.D. in Chemistry at the Martin Luther University of Halle-Wittenberg from where he moved for a postdoctoral stay at the Queen’s University in Ontario, Canada.