DRAFT of “Handbook of the Good Practices on Silk t

 

Mr. Jacques POULENARD

President of Quality and Technical Commission of INTERSOIE France

 

Introduction :

The aim of this project is to substitute to The ISA Standard manual of raw silk testing and classification a new upgraded document based on ISO standards in which will be included not only the technical characteristics needed by the users of the raw silk material but also the environmental and social issues linked with the the specificity of the raw silk chain of production.

That is a collaborative work between Italian delegates, French delegates (represented by the Technical and quality committee of Intersoie); Swiss delegates, to define the content of this new document and for sharing the tasks to engage.

This document could be a way to appreciate the efforts of the manufacturers all along the raw silk chain production on a technical point of view, on a qualitative point of view, on a reglementary and on an environmental and a social point of view.

My short lecture is going to present the state of progress with the draft. The document is based on the structure of the standards.

1. Scope

The many different processes in Silk production, the many different applications and also the many different people involved require different information about the quality and the behaviour of the Silk yarn or thread.

In reeling, trading, twisting, weaving, knitting or dyeing several quality aspects are of importance and must be known, but each process has different needs.

Testing means knowledge and it allows to take correct decision!

The objective of raw Silk testing and classification is to measure the quality of raw Silk, according to established reliable series of methods, and to determine the grade by the results of the quality tests, not only for facilitating a fair and equitable transaction of raw Silk, but also for providing a standard to support reelers, throwsters and weavers to select appropriate lots.

This document aims to introduce and update the methods for Silk quality measure with special focus on the methods using electronic instruments of the main characteristics of the raw Silk and the sustainability in terms of environmental and social responsibility.

2. Reference Documents

ISO 15625 – Electronic Test Method for defects and evenness of raw Silk ISO 21046 – Silk Test Method for size of Silk yarns

ISO 2062 – Yarns from packages – Determination of single-end breaking force and elongation at break using constant rate of extension (CRE) Tester.

ISO 6741 – Fibers and yarns – Determination of commercial mass of consignments

ISO 139 – Standard atmosphere for conditionary and testing

ISO DIS 21046 – Size of Silk yarns GB/T 1797 – Raw Silk

GB/T 1798 – Method for testing of raw Silk

ASTM D 3108 – Standard test method for coefficient of friction – Yarn to solid material

Other quality test methods related to more specific manufacturing processes are considered in the previous ISA standard manual as well in relevant national standard method (GB/T, ISO, JIS).

3. Definitions

Silk: Animal fibre produced by certain insects to build their cocoons and webs. They are several Silkworm, but the Silk produced by mulberry Silkworm is the main source of manufactured Silk, name mulberry Silk.

Raw Silk: Silk filament formed by conglutinating a number of Bombyx mori cocoon baves by reeling machine according to a certain reeling technique and quality requirements.

Silk brin: A Silkworm extrudes two single filaments named “brin”. The two “brin” cemented by sericin give a single thread named “bave”.

Skein: Silk reeled and removed from a re-reeling machine in the form of an open band. Weight of a skein: the weight of a raw Silk skein is 230 g – 330 g depending the customer’s request.

Lot: currently 600 kg of raw Silk in the form, for example, of skeins, or cones, etc.

4. Technical characteristics of raw Silk

4.1 Visual inspection

The purpose of this inspection is to detect unusual aspect of the raw Silk material.

The inspection is conducted on the whole lot of raw Silk and is carried out in an inspection room, which is well illuminated. It’s includes the Appearance and Nature.

4.2 Mechanical and Physical properties

Atmosphere for conditioning and testing; Sampling; Size of Silk yarns – ISO DIS 21046; Tenacity and elongation at break – ISO 2062; Evenness and defects – ISO 15625; Winding test – ISA Manual – 1968 Chapter 2 Article 3; Friction test - ASTM D3108; Cohesion test (standard to be set up); Commercial mass of consignments – ISO 6741-1 (reviewed in progress).

4.3 Miscellaneous Testing Methods

Boil-off test  (standard to set up)

The purpose of this test is to determine the percentage of sericin and water soluble substances which the Raw Silk contains.

All the new standards we need, must be developed with the assistance of the members of the International working Group of ISO TC 38 SC 23 WG5.

4.4 Raw Silk Classification

We need to a new classification of raw silk lots based on the electronic test results.

1.for the determination of the right price of a raw silk lot according to the test results including the electronic test ISO 15625.

2.for the orientation of the raw silk lot according to the end use of the yarn which will be produced.

This new classification has to be clearer than the usual electronic test reports and we have proposed in collaboration with Francesco Gatti, to try to represent the quality level of a raw silk lot with a radar representation.

5. Environmental issues

5.1 Sustainability

Silk is renewable material with a low environmental impact compared with other material.

The Silkworms need for growing mulberry leaves which don’t warrant much application of pesticides and fertilizers.

The mulberry Silkworm has been completely domesticated and cannot live without humans for their care and feeding. The production of raw Silk from the sericulture process to the industrial production is a labour-intensive process.

5.2 Mandatory rules applied to the Silk industry

We propose to focuse on the following synthesis of the chemicals applied in the Silk production chain according to the EU mandatory regulation rules, the Proposition 65 in California, and the China Rules.

The purpose of this chapter is to determine which chemicals registered in the mandatory rules, employed all along the Silk chain production, have to checked.

 

 

6. Social issues – (SA 8000)

First of all the company concerned has to comply with legal, regulatory and other requirements in respect of workers' health and safety in each country where a part of the Silk production chain is established.

The SA 8000 standard “Social Accountability 8000” specifies requirements for social accountability to enable a company to:

a)Develop, maintain, and enforce policies and procedures in order to manage those issues which it can control or influence;

b)Demonstrate to interested parties that policies, procedures and practices are in conformity with the requirements of this standard.

The requirements of this standard shall apply universally with regard to geographic location, and company size.

The company may implement a Management system in accordance with the SA 8000 standard requirements or has to respect at minimum the following items extracted from SA 8000.

In our draft we’ll extract the chapters which can be applied in our silk production chain.