SILK REELING AND TESTING MANUAL


Table of Contents

by

Yong-woo Lee
National Sericulture and Entomology Institute
Seoul
Republic of Korea

 

FAO AGRICULTURAL SERVICES BULLETIN No. 136

Food and Agriculture Organization of the United Nations Rome 1999

The designations employed and the presentation of material in this publication do not imply the expression of any opinion what so ever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.

M-17
ISBN 92-5-104293-4

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Contents

FOREWORD

CHAPTER 1 – INTRODUCTION

CHAPTER 2 – CHARACTERISTICS OF THE COCOON

    2.1 Physical characteristics of the cocoons
    2.2 Composition of the cocoon
    2.3 Properties of silk

CHAPTER 3 – COCOON QUALITY AND CLASSIFICATION

    3.1 Cocoon quality
    3.2 Factors influencing cocoon quality
    3.3 Classification of cocoons
    3.4 Cocoon testing and grading
    3.5 Cocoon exchange

CHAPTER 4 – COCOON DRYING, STORAGE AND SORTING

    4.1 Objective of cocoon drying
    4.2 Mechanism of cocoon drying
    4.3 Various methods of stifling/drying
    4.4  Degree of drying
    4.5 Types of drying machines and methods
    4.6 Effects of drying conditions on reeling results
    4.7 Cocoon storage
    4.8 Sorting of cocoons

CHAPTER 5 – COCOON COOKING 37

    5.1 Introduction
    5.2 Cocoon cooking methods
    5.3 Degree of cocoon cooking
    5.4 Adjustments to cooking conditions
    5.5 Effects of cocoon cooking conditions on reeling result

CHAPTER 6 – RAW SILK REELING

    6.1 Introduction
    6.2 Various silk reeling devices
    6.3 Methods of silk reeling
    6.4 Quality control during raw silk reeling

CHAPTER 7 – RE-REELING AND FINISHING

    7.1 Re-reeling
                7.1.1 Re-reeling machine and apparatus

                7.1.2 How to re-reel raw silk

                7.1.3 Re-reeling efficiency

                7.1.4 Silk end tying and skein lacing

    7.2 Booking and packing
    7.3 Storage of silk

CHAPTER 8 – UTILIZATION OF BY-PRODUCTS

    8.1 Introduction
    8.2 Doupion silk reeling
    8.3 Reeling of non-mulberry cocoons
    8.4 Manufacture of floss silk
                8.4.1 Degumming

                8.4.2 Opening-up

                8.4.3 Finishing

    8.5 Spun silk
                8.5.1 Introduction

                8.5.2 Yarn count of spun silk

    8.6 Wild silk

CHAPTER 9 – REELING WATER

    9.1 Type of water
    9.2 Impurities
    9.3 Methods of water softening
    9.4 Quality standard of water
    9.5 Analysis of reeling water

CHAPTER 10 – FACTORY PLANNING

    10.1 Annual requirement of cocoons
    10.2 Equipment for installation
    10.3 Location and space
    10.4 Quality and quantity of filature water
    10.5 Selection of proper machinery

CHAPTER 11 – RAW SILK TESTING

    11.1 Introduction
    11.2 Quality test
                11.2.1 Visual inspection
                11.2.2 Uniformity
                11.2.3 General finish
                11.2.4 Nature
    11.3 Sample test
                11.3.1 Winding test

                11.3.2 Size deviation test

                11.3.3 Evenness test

                11.3.4 Cleanness test

                11.3.5 Neatness test

                11.3.6 Tenacity and elongation test

                11.3.7 Cohesion test

    11.4 Quantitative test
                11.4.1 Conditioned weight test

    11.5 Raw silk classification
                11.5.1 Grades

                11.5.2 Grading with the major tests

                11.5.3 Degrading with the auxiliary tests

    11.6 Miscellaneous tests
                11.6.1 Boil-off test for raw silk

    11.7 Exfoliation test for raw silk

REFERENCES

APPENDIX (List of illustrations)

 

LIST OF FIGURES

1.     Size curvature of cocoon bave
2.     Neatness defects
3.     Texture of the silk thread
4.     Hysteresis phenomenon
5.     Shelf-carrier/Cabinet type dryer
6.     One step band type dryer
7.     Hot air circulating type dryer (section)
8.     Hot air circulating type dryer (side view)
9.     Low temperature air duct type dryer
10.   Air expansion in cocoon cavity and partially replaced with steam
        At high temperature permeation part
11.   Cocoon sucks in water at low temperature permeation part
12.   Cocoon cooking machine
13.   Ground plan of automatic reeling machine
14.   Side view of automatic reeling section
15.   Size detector (gauge type)
16.   Dimension and structure of semi-automatic reeling machine
17.   Spun silk manufacturing process
18.   Various cleanness

LIST OF TABLES

1.     World production of textile fibres
2.     Production of raw silk in the world 
3.     Daily loss in weight of fresh cocoons
4.     Variation of shell thickness in different parts
5.     Composition of cocoon
6.     Sericin content to different layers of cocoon shell
7.     Amino acid composition of fibroin and sericin
8.     Specific gravity and tensile strength of various fibres
9.     Effect of transportation containers of fresh cocoons on reeling results
10.   Cocoon classification systems of major sericultural countries
11.   Cocoon classification
12.   An example of cocoon pricing by visual inspection
13.   Optimum moisture content of dried cocoons
14.   Initial temperature for cocoon drying
15.   Effect of incomplete drying on result of reeling
16.   Qualities of raw silk reeled from sorted cocoons
16a. Criteria of insufficient and overcooking
17.   Adjustment of cooking methods depending on variations in cocoon
        quality
18.   Points for cooking operations
19.   Effects of cooking degrees on reeling results
20.   Comparisons of structural features of various reeling machines
21.   Effect of various reeling velocities on silk yield and quality with
        different grades of reelability cocoon
22.   Relationship between reeling velocity and evenness of raw silk quality
23.   Prevention method against various types of cleanness defects
24.   Temperature and humidity of rereeling in the machine
25.   Reeling efficiency of doupion silk by the sizes of thread
26.   A trial of Tasar cocoon reeling
27.   A survey of characteristics of Eri cocoon bave
28.   Yield of flow silk and spun silk by different cocoon raw materials
29.   Ion-exchange types and the quality of water treated
30.   Standard quality of reeling water
31.   pH values and water hardness suitable for cooking parts
32.   Items of machinery required for a silk reeling factory
33.   Building space required for each item of machinery to be installed 78
34.   Average speed and winding period for winding test
35.   Number of skeins in a lot and graduation in scale
36.   An example for size deviation test
37.   Deducting points by neatness results
38-1 ISA Classification table for raw silk of category I
38-2 ISA Classification table for raw silk of category II
38-3 ISA Classification table for raw silk of category III
39.   Chinese classification table for raw silk
40-1 Japanese classification table for raw silk of category I
        (18 denier and finer)
40-2 Japanese classification table for raw silk of category II
        (19 to 33 denier)
40-3 Japanese classification table for raw silk of category III
        (34 denier and coarser)
41-1 Indian classification table for Class I raw silk [ 2.0 tex (or 18
        denier) and finer]  
41-2 Indian classification table for Class I raw silk (2.1 to 3.7 tex
        or 19 to 33 denier)
41-3 Indian classification table for Class I raw silk (3.8 tex or 34denier and coarser)