LEATHER PROCESSING by Vaibhavi Kokane

LEATHER PROCESSING

VAIBHAVI KOKANE

Textile Value Chain

Introduction

In the strictest sense of the term, the ‘Leather Industry’ covers the preserving of the rawhide after the slaughterhouse and the tanneries which process the raw skins into durable leathers. India is the second-largest producer of footwear in the world. In India, there is a high earning foreign exchange and in leather is in the top 10 sectors.

Why the leather industry is in the top 10 sectors?

World’s 20% cattle production happens in only India, which means India is producing maximum raw material and in India there is maximum skill manpower, and using upgrade technology, international standard, etc. And that is the reason for India's share increases in competition. Process of Tanning: The flowchart below shows the complex process of Tanning Leather

Procuring animal skin

By Salting: Animal Skin is composed of 60-65 % water, 30-32 % protein, approximately 10 % fat, and 0.5 – 1 % minerals. It prevents putrefaction of the protein (collagen) from bacterial growth. Salt removes water from the hides and skins using a difference in osmotic pressure. In wet salting, the hides are heavily salted, then pressed into packs for about 30 days. In brinecuring, the hides are agitated in a saltwater bath for about 16 hours. Curing can also be accomplished by preserving the hides and skins at very low temperatures.

Pre-tanning or bean house operations

Soaking: The skins are de-haired, degreased desalted, and soaked in water for six hours to two days. To prevent damage of the skin by bacterial growth during the soaking period, biocides such as dithiocarbonates, 2 –thiocyanates, Ethylbenzothiazoline, etc. To protect wet leathers from microbial growth. Liming: After soaking the hides are treated with milk of lime supplemented by sodium sulphide, cyanides, amines, etc.

Unhairing and Scudding: Unhairing agents are used such as sodium hydroxide, sodium hydrosulphide, calcium hydrosulphide Dimethylamine, and sodium sulfhydrate. Most of the hair is then removed mechanically, initially with a machine and then by hand using a dull knife a process known as scudding. Deliming and Bating: Depending on the end-use of the leather, hides are treated with enzymes to soften them, a process called bating. Enzymes act properly so the pH of the collagen is brought down to a lower level so the enzymes may act on it, in a process known as de- liming. Pickling: Once bating is complete, the hides and skins are treated first with common salt (sodium chloride) and then with sulphuric acid in case a mineral tanning is to be done. This process is known as Pickling. The salt penetrates the hide twice as fast as the acid and checks the ill effect of the sudden drop of PH. Chrome Tanning: Chromium(ll) sulphate and sodium bicarbonate (base) are added to this process. Chromium(ll) sulphate is used as a tanning agent. Chromium(ll) sulphate dissolves to give the hexaaquahromium (ll) cation, which at higher pH undergoes processes called olation to give polychromies(ll) compounds that are active in tanning, being the cross-linking of the collagen subunits. The cross-linkage of chromium ions with free carboxyl groups in the collagen. It makes the hide resistant to bacteria and high temperature. The chromium-tanned hide contains about 2-3% by dry weight of Cr Vegetable Tanning: Hides are kept immersed in Tannin liquor for several weeks in series of vats with increasing concentration of tannins. Tannins bind to the collagen proteins in the hide and coat them, causing them to become less water-soluble and more resistant to bacterial attack. The process also causes the hide to become more flexible. The vegetable-tanned hide is not very flexible. It is used for luggage, furniture, footwear, belts, and other clothing accessories.

Procuring animal skin: The animal is killed and skinned before the body heat leaves the tissues.

Curing is the preservation of hides. Curing can be performed in different ways.

GLOBAL LEATHER MACHINERY EXPORT HIT HARD

BY COVID-19 PANDEMIC

Textile Value Chain

Leather manufacturing had always been a procedure which was performed manually with the help of tools. In the recent years, machinery has taken over the leather manufacturing industry. Leather machinery is taking over the leather production industry due to its recent advances that reduce time, cost and manpower required for leather production. The coronavirus pandemic had a lot of adverse effect on the global textile industry. Leather machinery exports witness this impact globally. A subsequent decrease was witnessed in the export of leather machinery in the year 2020 due to the pandemic. China was the leading exporter of the leather machinery in the year 2019 as well as 2020. Its export was worth 527 million dollars in the year 2019. The export dropped drastically in the year 2020 due to the covid-19 pandemic. Though a reduction in the export was witnessed, China’s global share in leather machinery export climbed up from 39% in 2019 to 41% in 2020.

Italy was the second largest exporter of leather machinery in 2019 and 2020 with the export worth 394 million dollars and 272 million dollars. Records suggest that it was the top exporter for the past 3 years from 2016-2018 but China’s export drastically increased in 2019, while Italy’s export dropped dramatically. Its share in the global export of leather machinery in the year 2020 was 32%.

Due to the covid-19 pandemic, almost all the nation’s exports dwindled in 2020. Taiwan’s export of leather machinery was one $28 million in the year 2019 due to the pandemic its export decreased to $76 million in 2020. Not only the exports but even its global share fell from 10% to 9% in the year 2020. Turkey's contribution was worth 1% in the global share of leather machinery export. Turkey's global share remains same in both the years. Its export was worth 11 million Dollars in the year 2019. These exports drastically shrinked to $5 million in the year 2020. USA was surprisingly not among the top exporters of leather machinery. Its export was worth $15 million and $10 million in the year 2019 and 2020, respectively. Its contribution was 1% in both years to global share. France was the only nation that witnessed a hike in export in the year 2020. Its export was worth $19 million in 2019, in 2020 its export increased to $19.6 million. Its contribution to the global share was one person in the year 2019. There was a subsequent increase in its global share in 2020 which was 2%.

Korea's export was worth $87 million in the year 2019. There was a dramatic decrease in its export in the year 2020 due to the pandemic. Korea's export fell to $46 million in the year 2020. Its global share was 7% in the year 2019. There was a decrease in its global share in the year 2020. Its global share was 6% in the year 2020. Germany's export was worth $54 million in the year 2019. Like other nations Germany also witnessed decrease in its export in the year 2020 due to the pandemic. Its export was worth $46 million in 2020. despite the decrease in the export in the year 2020 Germany witnessed a hike in its global share from 4% in 2019 to 6% in 2020.

Hong Kong exported the leather machinery's worth $19 million in the year 2019. Its export dwindled to $8 million in the year 2020 due to the pandemic. Its global share remained 1% in both the years for the same. Though Spain was among the top ten exporters of leather machinery, its export was word $13 million only in the year 2019. Its export filled two $9 million from$13 million in the earlier year in the year 2020 due to the pandemic. Its global share remained 1% in both the years for leather machinery export. The export done by other countries was worth $83 million which was even less than Korea in the year 2019. This export fell drastically two $55 million in the year 2020 due to the pandemic.