Eco-Technology for Leather Production

A Reference Guide

No part of this guide may be reproduced or transmitted in any form or by any means, without permission in writing from the Hong Kong Hide & Leather Traders¡¦ Association Limited.

»´ä¥Ö·~°Ó·|¦³¤½¥q THE HONG KONG HIDE & LEATHER TRADERS' ASSN., LTD. Unit B, 3/F., Capital Commercial Building, 446-448 Shanghai Street, Kowloon Telephone : (852) 2388-7644 Fax : (852) 2783-0804 Email : info@leatherassn.com Website : www.leatherassn.com

First published 2005

Printed in Hong Kong. All rights reserved.

Implemented by

Hong Kong Productivity Council

Funded by

Innovation and Technology Fund of HKSAR Government

Acknowledgements

This reference guide would not have been possible without the valuable contributions of the following individuals and organizations in the respective areas.

The Hong Kong Hide and Leather Traders' Association wishes to record its deep appreciation to all of them.

Information and Advice l Mr. Tommy Fong and Ms. Wendy Lai of Hong Kong Footwear Association Limited l Mr. William Tsang of HK Leather Shoe and Shoe Material Merchants Association Ltd. l Mr. Tang Yau Choi of China Leather Industry Association l Mr. Henry Chow of The Association of HK Gloves Traders Ltd. l Mr. Derek Lee of Fongstar Handbag Co., Ltd. l Mr. Lawrence Wong of Leather & Trading Co., Ltd. l Mr. Spencer Yeung, Mr. Alex Kwong and Ms. Ann Lam of SGS Hong Kong Ltd. l Dr. Samuel Wong of Bureau Veritas, Consumer Products Services (HK) Ltd. l Mr. Walter Lui and Mr. Ricky Yan of TFL Hong Kong Ltd.

l Gap Inc. l Kingston Tannery l Sun Holy Manufactory Ltd. l Girraween Ltd. l Wah Kiu Leather Co., Ltd. l Cheong Fat Leather Co., Ltd. l Dr. Boehme Chemical Co. (Germany) l Codyeco spa (Italy) Financial Support l Innovation and Technology Commission, HKSAR Government Project Team l Mr. Wong King Hang l Hong Kong Productivity Council

Kong Kin Fai

Chairman, The Hong Kong Hide and Leather Traders' Association Limited

CONTENTS

Introduction

Section 1

Introduction to Leather Production Process
1.1	Beamhouse Process
1.2	Tanning Process
1.3	Finishing Process
1.4	Consumptions of Water and Chemicals of a Tannery

Section 2

Sources of Waste
2.1	Salted Stocks
2.2	Soaking
2.3	Unhairing and Liming
2.4	Fleshing and Splitting
2.5	Pelt Deliming and Bating
2.6	Pickling and Chrome Tanning
2.7	Sammying and Shaving
2.8	Neutralisation, Re-tanning, Dyeing and Fat Liquoring for Chrome Tanned "Wet-Blue"
2.9	Vegetable Tanning Process
2.10	Summary of Pollution Loads Discharged in Efluents from Individual Processing Operations

Section 3

Government Regulations and Commercial Production Requirements on Discharge Level of Pollutants from Leather Production
3.1	Regulationof Discharge of Pollution Load from Leather Production in China
3.2	Discharge Standards for Tannery Waste Waters for Several Countries
3.3	CEKO - Standard
3.4	German SG Mark
3.5	ICT Eco - Toxicity Guidelines
3.6	Regulation / Requirement and Test Methods for Restriced Substances
3.7	Determination of the Performances of Car Seat Leater
3.8	Methods for Determining the Amount of Hazardous Substances in Leather Product

Section 4

Cleaner Technology for Leather Production
4.1	Rawstock Preservation
4.2	Beamhouse processing
4.3	Tanning Operations
4.4	Post-tanning operations
4.5	Finishing Operations
4.6	Waste Minimisation and Good House Keeping

Section 5

Chrome Free Leather Processing Trials
5.1	Experimentation Plan
5.2	Details of the Processing Procedures of the Experimentations
5.3	Application of Chemicals for Eco-Leather Production
5.4	Testing Results of the Effluents Collected at Various Stages of the Experimentation Process
5.5	Testing Results of Leathers Produced from Experimentation
5.6	Shrinking Test Result of Leathers Produced from Experimentation

Section 6

Conclusion
6.1	Market for Eco-Leather Products
6.2	Production Practice
6.3	Modification of the Manufacturing Process for Eco-leather

Appendix 1

Analyis of Survey of "Eco-technology for Leather Production"

Introduction

Introduction

Processing hides and skins and converting them into leathers has long been an important industrial activity. The tannery operation involves a sequence of complex chemical reactions and mechanical processes and has always been associated with odour and pollution.

Amongst these, tanning is the fundamental stage, which gives leather its stability and essential character. It is done by chemical reaction between natural tannin, chromium salts or other chemicals and collagen (protein) in the hides. Of world tanneries, 80 ¡V 95 % use chromium salts in their tanning processes. The potential hazards of chromium are complex, for example, chromium in its hexavalent state causes cellular damage via its role as a strong oxidising agent which passes readily through membranes.

The globalisation of the leather industry means that all tanners face the same problems of minimising the environmental impact of processing and selling into the global market.

Now, more and more Western countries have defined their requirements on chrome-tan leather and its products. Some infant shoes importers are demanding chrome-free leathers. Chrome-free tanning can achieve 80% of the good thermal stability property of the leather produced by the conventional chrome-tanned method and such quality standard is widely accepted by importers in developed countries.

In order to enhance the competitiveness and responsiveness of Hong Kong leather industry to market demand on chrome-free leather, the Hong Kong Hide and Leather Traders¡¦ Association and the Hong Kong Productivity Council (HKPC) proposed a project to develop eco-technology for cleaner tanning production.

The project work included collection of information on eco production methods for leather production in advanced countries; setting up a pilot chrome-free tanning production system for experimentation of chrome-free processes; compilation of a reference guide containing eco-technology in various stages of leather production and details of the procedures of the chrome-free tanning trials; an abridged version was up-loaded to the web site of the Hong Kong Hide and Leather Traders¡¦ Association; and establishment of a library with collection of project information and trial samples at the Hong Kong Hide & Leather Traders¡¦ Association for easy access by the trade.

The information provided inside this guide is of a general nature and is given for reference only. Companies are advised to make their own checks on some of the factors which, depending on their specific situation, may deviate from those that obtained during the project. The Project Team makes no warranty, express or implied, nor assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, equipment, product or process disclosed, nor represents that its use would not infringe privately own rights. Reference herein to any special commercial product, process by trade name, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favouring by the Project Team thereof.

Section 1

Introduction to Leather Production Process

1.1	Beamhouse Process
1.2	Tanning Process
1.3	Finishing Process
1.4	Consumptions of Water and Chemicals of a Tannery

Section 1

Introduction to Leather Production Process The leather production process is divided into three main stages namely beamhouse, tanning and finishing operations.In the beamhouse, there are soaking, liming, unhairing with sulfide, fleshing, trimming, deliming and bating processes to remove unwanted parts such as hair, skin, hoof, etc. The hides are then prepared for the subsequent tanning process. Tanning is to change decomposable raw hide to finished leather which is more stable, not decomposable, and resistant to weather condition and heat. After tanning, the hide or skin is kept in a comparatively stable stage for further trimming, selecting mechanical operation according to its quality. Then it is ready for sale or further processing. Finishing processes include re-tanning and fat-liquoring to improve quality of the tanned product, dyeing to achieve the customer's required colour, and spraying, pattern printing, etc to fulfill the market demand or customer requirement. Table 1-1 is the processing steps for leather production from raw hides.

Table 1-1 Process steps for the production of leather from raw hides

	Chrome tanned leather	Vegetable tanned leather
Beamhouse	Soaking	Soaking
	Liming	Liming
	Fleshing Splitting