CHAPTER ONE

INTRODUCTION

1. BACKGROUND OF THE STUDY

Processing of skin or hides into stable material – leather is known as tanning. Leather, the primary product from the tanning industry, where the product has got its applications in making footwear, furniture, bags, etc. The global leather industry generated about 18 billion square feet leather in 2003 with an estimated price of US$40 billion (World Leather Magazine). Most developing countries including India are producing 60 % of world’s leather needs. For making the leather, Tanning is considered as a major process which involves more chemical reactions as well as mechanical operations. During the process more chemicals including chromium, acid solvents, etc are involved, these processes release effluent of 30L/kg of processed skin, where tanneries of India are releasing effluent more than 50,000 mg/day with huge quantity of organic pollutants. 70% of chrome (III) is usually discharged (IULTCS, 2008) and leads to heavy metal contamination in water. Release of chromium by tanneries is higher now than mentioned parameters.

The global leather has been in existence during which technologists were concerned to inflict stability to raw skins and hides. Until the approach of chrome tanning, there were very few options available for tanners such as aluminium tawing, smoke tanning, oil tanning and vegetable tanning. The term tannin was firstly used in 1796 by Seguin in order to specify the specific components of vegetable extracts having a potential to bind with collagen making insoluble complexes by blocking the action of other proteolytic enzymes which affect the physical condition of the skin (Terrel, 2009). The process of this extraction may include non-tannins and other materials which have no tanning strength which contributes in determining the functional properties of the leather. Oils of animals Leather are also smoke tanning where the oil in animals’ brain used as tanning agent which gives highly durable leather (Tegtmeger, 2013). Today chrome tanning is the most commonly used method which accounts for world’s leather production.

Sheep skins are an important source of raw material for tanning industry. They are considerably smaller than hides (Ian Leach, 1995). In Egypt there are 4,450,000 heads of sheep (FAO, 2002 a) produced 2.7 million pieces of skin weighed 1600 tones (dry weight) and the export value of skin averaged 2.8 million US$ (FAO, 2002 b). There are about 702,213 heads of the Barki breed located in the North Western Coastal Zone, (Younis, 1995).

The art of technique to convert hides and skins into leather is called tanning. Leather is animal skin so treated that it becomes more permanently resistant to decomposition when wet, and supple when dry (Mann, 1960), because the tanning process converts the protein of the raw skins into a stable material (Tereza Varnali, 2004).

Mineral and vegetable tanning are the most common methods used in tanning (Yazicioglu & Boler, 1983; Bayer, 1987 and Anthony,1998). Chrome tanning is frequently used in mineral tanning (Fred O’Flaherty et al., 1958). It is based on the reaction between the collagen fiber in raw skin and a trivalent chromium salt (Virve et al., 2000). On the other hand, leaves, fruits, barks, wood and roots of various vegetables contain tannins that can be used as tanning agents (Parthasarthy & Kamath, 1974; Yazicioglu & Boler, 1983 and Tereza Varnali, 2004). In the meantime quebracho and mimosa are the most materials used in vegetable tanning which contains 35% and 18% tannins in the bark or wood, respectively (Mann,1960).

Chrome-tanned leather tends to be softer, more liable, has higher thermal stability, very stable in water, and takes less time to be produced than vegetable-tanned leather, (Yazicioglu and Boler, 1983). Today, mineral tanning is particularly popular because it is effective and efficient. However, vegetable tanning is still used for certain purposes, i.e. making some shoes, soles, bags, and luggage cases (Ian Leach, 1995).

Although, the future of tanning industry lies with chromium salts (Anthony, 1998), it represents one of the common sources of metal pollutants in the environment by discharging tannery wastes directly into sewage system (Chakir, 2001). Thus, the present investigation aimed to study the effect of tanning methods and regions on physical and chemical properties of Barki sheep leather.

1. STATEMENT OF THE PROBLEM

Anthony (1998) reported that the future of tanning industry lies with chromium salts. The tanneries discharge its waste water into the sewerage network. Effluents wastes contain various chemicals, two of which are the polluting chemicals that pose a serious threat to the environment. These are sulfides used in the unhairing process and chromium salts used for chrome tanning. The influence of tannage on skin physical properties is certainly real, but it is difficult to assess, quantitatively, the changes in these properties as a function of tanning. The processes of tanning interact to give the feel associated with the different commercial leathers, so it isn't surprising that the specific influence of tanning on physical properties is not known.

The global leather industries have been in existence for over 400 years and during that time technologists have been concerned to impose stability to the raw hides and skins (Covington, 2009). Until the advent of chromium tanning, toward the end of 19th century, the options available to the tanner were limited to the following processes: vegetable tanning, aluminium tawing, oil tanning and brain and smoke tanning (Covington, 2009).

It is in the light of the above and the existing gaps in literature that the study seeks to investigate the relationship effect between tanning methods and quality strength of leather.

1. AIM AND OBJECTIVES

The aim of the study is to investigate the relationship effect between tanning methods and quality strength of leather.

Specifically, the study sought to:

1. Ascertain the historical background and growth of leather industry
2. Examine critically the role of various Governments and  organizations in the development of leather industry
3. Identify challenges and problems facing the quality strength of leather  
4. Evaluate the prospects of leather industry

1. RESEARCH QUESTIONS

Arising from the research objectives, the following research questions will be critically addressed as presented below:

1. What is the historical background and growth of leather industry
2. What are the role of various Governments and  organizations in the development of leather industry
3. What are the challenges and problems facing the quality strength of leather  
4. What is the prospects of leather industry

1. RESEARCH HYPOTHESIS

H0 there is no relationship effect between tanning methods and quality strength of leather

H1 there is relationship effect between tanning methods and quality strength of leather

1. SIGNIFICANCE OF THE STUDY

The study is on the impact of tanning methods on the quality and strength of leather is very important especially as leather work is the trending issue in the production industry.

The study findings will be highly useful to the shoe makers, bags, belts etc on the knowledge impact of tanning methods on the quality and strength of leather.

Ultimately, the study will reveal the challenges and problems facing the quality strength of leather and the prospects of leather industry which will be highly beneficial to the leather production industry.

1. SCOPE OF THE STUDY

 The study focuses mainly on investigating the impact of tanning methods on the quality and strength of leather, specifically; the interest of the study will be restricted on the leather production industry department, due to time and financial constraints. Thus, the investigation of the study will be conducted within leather industry and the focus of the study will be on members and staff of leather production industry.

1. LIMITATION OF THE STUDY

TIME CONSTRAINTS: One the challenges experienced by the researcher is the issue of time; the research will simultaneously engage in departmental activities like seminars and attendance to lectures. But the researcher was able to meet up with the deadline for the submission of the project.

FINANCIAL CONSTRAINTS: Every research work needs funding; however lack of adequate funds might affect the speed of the researcher in getting materials for completion of the project.

1.9 DEFINITION OF TERMS

 Tanning

The action or process of converting animal skin into leather by soaking it in a liquid containing tannic acid, or by the use of other chemicals.

 Chromium

Chromium is a chemical element with the symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard, and brittle transition metal. ... The name of the element is derived from the Greek word χρῶμα, chrōma, meaning color, because many chromium compounds are intensely colored.

Leather

Leather is a durable and flexible material created by tanning animal rawhide and skins. The most common raw material is cattle hide. ... Leather is used to make a variety of articles, including footwear, automobile seats, clothing, bags, book bindings, fashion accessories, and furniture.