Effect of Mechanical and Physical Properties on Fabric Hand

H Behery

• Publisher: Woodhead Publishing
• Year: 2005
• Print ISBN: 9781855739185
• eBook ISBN: 9781845690984
• Topic: Tecnología e ingeniería
• Subtopic: Ciencias de los materiales

It is a consumer's instinct to use the sense of touch when choosing a garment; to describe and assess the fabric quality and its suitability for a specific end use. The way that the fabric feels is described as its handle or 'fabric hand'. Fabric hand can be evaluated by mechanical or electronic devices and by human judges using psychophysical or psychological techniques.Effect of mechanical and physical properties on fabric hand thoroughly explores the techniques and issues involved in this difficult subject. It begins by looking at the concepts of fabric hand, with chapters on the developments in hand measurement, the application of statistical methods and the differences in fabric hand between different cultures. The second part is devoted to the different effects fiber, yarn and fabric can have on fabric hand. The effect of factors including fiber, yarn and woven fabrics are all outlined in separate chapters. Finally, the third section describes the effect that processing has on fabric hand. This includes processes such as wet processing and chemical finishing, mechanical finishing and refurbishing. Finally two important appendices are included for reference. Appendix A is from the Hand Evaluation and Standardization Committee and outlines the Kawabata system for standardization and analysis of hand evaluation. Appendix B describes the SiroFAST system of fabric assurance by simple testing developed by CSIRO, Australia.With an international panel of distinguished contributors, Effect of mechanical and physical properties on fabric hand provides comprehensive coverage on the subject. It will be an essential work for those researching and working in apparel and fashion design, textile selection, fabric designers and developers, manufacturers, and those interested in fabric dyeing and finishing. - Essential reading for all those working in apparel and fashion design, textile selection, fabric design and development and fabric manufacturers - Covers statistical methods in evaluating hand and a comparison of hand evaluation in different cultures - Looks at the effect processing has on fabric hand

1

Introduction

H M BEHERY, Clemson University, USA

Publisher Summary

A critical property of fabric in its end use is its performance and how it withstands washing and/or dry cleaning to maintain its hand. Consumers instinctively use fabric hand to describe and assess fabric quality and its suitability for a specific end use. Fabric hand could be evaluated by mechanical and electronic devices and by human judges using psychophysical or psychological techniques. Judgments of fabric hand provide understanding of underlying fabric properties. In the measurement of fabric hand, psychological approaches use consumer judges, because sensory evaluation of fabric hand by consumers gives information about their perceptions and preferences for fabrics for specific end uses. In early studies, fabric hand was defined as a subjective property evaluated by consumers. The need for developing means to evaluate fabric hand objectively has been recognized over many years. Nowadays, several instrumentations are available and testing measurements and techniques are in use in the textile industry, as well as in research and development work.

1.1 Historical

Consumers instinctively use fabric hand to describe and assess fabric quality and its suitability for a specific end use. Fabric hand could be evaluated by mechanical and electronic devices and by human judges using psychophysical or psychological techniques. Judgments of fabric hand provide understanding of underlying fabric properties. In the measurement of fabric hand, psychological approaches use consumer judges, because sensory evaluation of fabric hand by consumers gives information about their perceptions and preferences for fabrics for specific end uses. In early studies by Schwartz¹ and Brand,² fabric hand was defined as a subjective property evaluated by consumers.

The need for developing means to evaluate fabric hand objectively has been recognized over many years. Several instruments have been designed, redesigned and developed for the measurement of fabric mechanical properties and have evolved through the pioneering work of Peirce³ in 1930, which quantified the relationship between measurable fabric properties and hand.

Nowadays, several instrumentations are available and testing measurements and techniques are actually in use in the textile industry, as well as in research and development work. These are presented and discussed in Chapters 2 and 3.

1.2 Definition and concept of fabric hand

Fabric hand has been defined⁴ as ‘… the subjective assessment of a textile obtained from the sense of touch. It is concerned with the subjective judgment of roughness, smoothness, harshness, pliability, thickness, etc.’. Judgments of fabric hand are used as a basis for evaluation quality, and thus for determining fabric value, both within the textile, clothing, and related industries and by the ultimate consumer. Studies of fabric hand may be of major commercial significance if, for example, they assist in explaining hand assessment or provide a means of its estimation based on objective measurement. It is necessary to examine the subjective assessment of hand before examining its relationship to fabric mechanical and surface properties.

1.2.1 Review of the literature for definition of fabric hand

Peirce³ described hand as being the judgment of the buyer, which depends on time, place, season, fashion, and personal predilections. Therefore, the intention to replace expert human assessors by numerical data from physical testing would be worthless. What human fingers sense, on the other hand, depends upon the physical properties of the cloth, so that data from physical measurements can provide a basis upon which to exercise judgment.

In a series of technical investigations of textile finishing treatments, Schwartz¹ defined hand of a fabric as a property judged as a function of the feel of the material, and explained that the sensation of stiffness or limpness, hardness or softness, and roughness or smoothness constitutes hand. He reported the desirability of physical testing which may analyze and reflect the sensations felt and which can assign numerical values to the measurements of these parameters.

Patterson⁵ studied the causes of changes of hand in woolen fabrics. He defined fabric hand as a certain quality expressed by an individual reaction through the sense of touch upon examining a fabric or one or more fabrics of the same quality. He explained that a woolen fabric may be described as having a good hand, which may be further classified as soft, slick, sharp, woolly, smooth, or silky; if the hand is poor, it may be described as harsh, greasy, gummy, sticky, boardy or dry. However, he concluded that the question of hand of fabrics has been complicated because of the inability to evaluate this property of a fabric by any definite or standard method.

Hoffman and Beste,⁶ in their study of fiber properties related to fabric hand, reported that fabric hand means the impressions that arise when fabrics are touched, squeezed, rubbed, or otherwise handled. The handling of a fabric may convey visual impressions as well as tactile ones; therefore, it seems proper to include luster and covering power in the properties considered.

Thorndike and Varley⁷ studied the frictional property of fabrics as related to hand, and defined hand briefly as a person’s estimation when feeling the cloth between fingers and thumb. Their discussion is based on the assumption that the static and/or dynamic coefficient of friction between the cloth surface and the thumb or fingers is one of the factors which influence the subjective judgment of fabric hand, although flexibility, thickness, and other properties of the material may also be involved when making such an assessment oí cloth quality.

Mechanical properties related to the hand of heavy fabrics were investigated by Kita Zawa and Susami.⁸ They introduced the term ‘synthesized hand’. They discussed whether hand is a psychological phenomenon and whether, if hand is defined as a perceptible pattern obtained by the tactile sense of fingers, transmitted by the nervous system and assessed by the brain, explanation of the sensory pattern in a direct and objective way without clarifying the mechanisms of the sensory organs, nervous system and brain will be impossible. If so, expressing the sensory values of a fabric obtained by different assessors by use of a statistical technique becomes inappropriate. The very difference in the results of hand assessment by different assessors is an important factor in defining hand. Each assessor forms his or her own idea about the pattern of a given fabric; however, regarding such elementary sensory properties as stiffness, thickness and warmth, it is possible that communication between assessors may constitute a common idea, such as ‘wool hand’ or ‘silky touch’. This common and qualitative idea formed by an assessor about the multiplicity of resembling samples is defined as ‘synthesized hand’. A series of basic mechanical properties are assumed to govern the synthesized hand of a fabric. Then, it is possible to develop a correlation between the synthesized hand and the pattern of the mechanical properties of standard samples, provided that this standard pattern can be established.

Lundgren’s⁹ concept of fabric hand is that hand is considered as the summation of the ‘weighed’ contributions of stimuli evoked by a fabric on the major sensory centers presumably present in the human hand. Such centers can be uniquely sensitive to such physical properties as roughness, stiffness, bulk and thermal characteristics. He also stated that the term ‘hand’ is used to describe the tactile and muscular (kinesthetic) sensations produced by a fa...

Table of contents

• Cover image
• Title page
• Table of Contents
• Related titles from Woodhead’s textile technology list
• Copyright
• Dedication
• Contributor contact details
• Preface
• Chapter 1: Introduction
• Part I: Understanding and evaluating fabric hand
• Part II: Effect of fibre yarn and fabric factors on fabric hand
• Part III: Effect of processing on fabric hand
• Appendix A: The Standardization and Analysis of Hand Evaluation (second edition)
• Appendix B: SiroFAST – fabric assurance by simple testing
• Index