Advanced Fiber Spinning Technology

T. Nakajima

• Publisher: Woodhead Publishing
• Year: 1994
• Print ISBN: 9781855731820
• eBook ISBN: 9781845693213
• Topic: Technology & Engineering
• Subtopic: Materials Science
• Index: Technology & Engineering

Translated from Japanese, this book details some of the most interesting developments of the last few decades in the field of fibre manufacture. Many of these have been the result of intensive study in industry and research institutes in Japan - the country at the forefront of research in fibre spinning technology.

1

Fundamentals of spinning

Ken-ichi Katayama Takuma National College of Technology, Takuma-cho, Japan

Masaki Tsuji Institute for Chemical Research, Kyoto University, Japan

There are a great many subjects covered by the heading ‘Fundamentals of spinning’. In this chapter, however, we confine ourselves to a description of the fundamentals of mathematical simulation for spinning and of new findings on structural formation during spinning and fiber structure. This description should be undertaken for each of the three types of spinning: melt spinning, dry spinning and wet spinning. However, we are concerned here mainly with melt spinning because it is the easiest for us to formulate and accordingly its theory is the most sophisticated of the three. The others are described only briefly with literature references to the details. Nevertheless, the authors hope that this short treatise will help the readers to understand other parts of this book.

1.1 Introduction

The viscose rayon method was developed towards the end of the last century and the melt spinning method for synthetic fibers was established in the early part of the 1930s. In the beginning of the history of spinning, progress in spinning technique was mainly made by accumulating empirical facts; that is to say, by repeating a set of procedures such as setting a spinning condition and measuring the resultant properties and structures of the spun fibers. There were few studies on physiochemical changes and on structural formation in the spun fibers between the spinneret and the take-up device. With the rapid advance of the synthetic fiber industry in the 1940s, a strong need arose to understand the basics of the spinning process in order to improve the productivity and quality control of the fibers. Consequently, towards the end of the 1950s, Ziabicki published a series of papers concerning melt spinning in which the spinning process was analyzed mathematically as an engineering problem: the papers served as a powerful incentive to researchers in this field of study. About the middle of the 1960s, Kase and Matsuo^1,2 established a method for the quantitative description of the melt spinning process based on hydrodynamics, rheology and the theory of thermal conduction. Subsequently, Katayama et al³ studied structural formation and crystallization during a melt spinning process by using a special model spinning apparatus. From then on, studies in this field have been extensively carried out in Japan and elsewhere and most of the results are to be found in several references.⁴⁻⁹

In melt spinning, we can predict the diameter and temperature and the tension in a running filament if the spinning conditions and the rheological properties of a polymer used in the spinning process are given; the predicted values are, of course, in good agreement with the experimental results. Such a prediction, however, can be made only when no significant crystallization occurs during the spinning process. If crystallization must be taken into consideration, it becomes increasingly difficult for us to carry out mathematical simulation of the quantities mentioned above.

In this case, full quantitative knowledge of the following four points is needed for performing a mathematical simulation of melt spinning:

1 Molecular orientation caused by elongational melt flow.

2 Influence of molecular orientation on crystallization kinetics.

3 Changes in the rheological properties of the polymer caused by molecular orientation and crystallization.

4 Kinetics of non-isothermal crystallization.

The correlation between the above points is shown in Fig. 1.1. In this figure, an arrow indicates that an item from which the arrow starts influences another item to which the arrow is pointing.

1.1 Correlation between factors governing the melt spinning process

In the theory of Kase and Matsuo, mean values of temperature and of stress over the whole area of a transverse section of the filament were used. In the process of high speed spinning, however, the variables such as temperature, stress, orientation and crystallinity must be expressed as functions of the radial distance from the central axis of the filament as well as the distance from the spinneret. For example, consideration of the radial distribution of these variables is inevitable in discussing inhomogenous structures...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright page
• Contributors
• Preface
• Introduction
• Japanese Patents: explanatory note
• 1: Fundamentals of spinning
• 2: Melt spinning
• 3: Solution spinning
• 4: Spinning for nonwovens
• 5: The spinning of highly aesthetic fibers
• 6: Fiber spinning of anisotropic polymers
• 7: Spinning of Thermotropic Liquid-Crystal Polymers
• 8: Gel spinning processes
• 9: Spinning of ultra-fine fibers
• 10: Spinning of optical fibers
• Appendix: Microscopic views of Shingosen
• Index