Industries using livestock products for processing
Leather industryIs usinglivestock productsThe processing industry uses animal hides as the main raw material for serial processing.It generally includes the leather industry with raw hides as the processing object, the leather shoes manufacturing industry with leather as the main raw material, and other leather products processing industries, as well as the fur processing industry and the manufacturing industry of supporting materials and professional equipment.
With the increasingly extensive use of leather products and the rapid development of synthetic materials, shoes, boxes, bags, bags, gloves, etc., which have always used leather, have also partially used artificial leather, synthetic leather and other non natural leather materials.
brief introduction
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Due to different livestock varieties and feeding conditions, the quality of animal hides as raw materials for leather and fur varies, such as different widths, thicknesses and weights.As far as a piece of rawhide is concerned, the tightness and thickness of fiber tissue in each part are uneven.The primary purpose of leather industry production is to adopt a variety of methods to transform different hides into more uniform leather and fur, so as to keep their quality consistent and stable.Therefore, both chemical treatment in batches and single machine sheet by sheet operation are available in tanning and fur production.Although the production of shoes and other leather products has been mechanized, it still needs superb skills and experience to produce high-quality products.
Development history
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prehistoric
In prehistoric times, human beings used animal skins to wrap their bodies for warmth and feet, which can be regarded as primitive leather clothing, boots and shoes (seeHistory of leather technology)。1000 BC ago, the ancient Greeks used leather products for commodity trading.In the 9th century BC, the ancient Egyptians used leather products.In the 13th century, the production of leather and fur in China has been relatively developed. Marco Polo wrote in his travel notes that Genghis Khan's army wore leather armor and used leather bags to hold water and cheese for marching and fighting.In the 18th century, the gradual development of modern science and technology laid the foundation for the formation of the leather industry.At the end of the 19th century, the chemical basic substances of leather and fur, collagen and keratin, were further understood. With the advent of chrome tanning technology, leather manufacturing gradually developed from experience to an engineering technology, which promoted the leather production technology and the manufacturing of supporting machinery and equipmentChemical materialsProduction has developed into a new industry.Since then, the technical control and production management have been increasingly improved, and the quality of all kinds of leather has been basically stable and consolidated, so as to meet the requirements of large-scale production of mechanized shoes and other leather products.At the beginning of the 20th century, various leather industrial systems with different characteristics were gradually formed in many countries, and machinery and equipment were further developed. In addition to natural tanning agents, many kinds of tanning agents were also developedSynthetic tanning agent, additives, fatliquoring agents, finishing agents, etc., leather production is becoming more and more modern.By the end of the 1980s, leather and shoe making had partially realized continuity on the basis of mechanized production, and some had also adopted microcomputer and electronic computer automatic control technology.
Industrial period
Countries with relatively developed modern leather industry include the United States, Italy, the Soviet Union, the Federal Republic of Germany, the United Kingdom, Spain, Brazil, etc.The tanning, shoemaking and other leather products industries in these countries are closely related toSupporting materialsThe manufacturing industry closely cooperates and develops synchronously, forming a production system centered on finished products such as shoes and other leather products.With the development of leather industry, international cooperation and academic exchanges have become increasingly widespread.The leather industry and supporting material manufacturing industry exchange information with footwear and other leather product manufacturing industries, predict changes in popular styles and colors, promote each other and develop as a whole.
In 1987, the total world leather output was 1.39 billion square meters, of which the output of various types of leather is shown in the table.The total output of footwear in the world was about 5.8 billion pairs in 1975 and 8 billion pairs in 1988 (half of which were natural leather shoes).China is rich in pig skin and goat skin resources. At the end of the 1980s, the production of pig leather ranked first in the world.
With the expansion of production scale, toxic and harmful waste water containing sulfur and chromium ions discharged from tanning production has become increasingly serious public hazards.Generally, the following two methods are adopted: one is to treat toxic and harmful wastewater by mechanical, chemical and biochemical methods;The second is to reform the production process, develop and apply products that can reduce pollutionChemical materialsStudy on enzymatic unhairing process, less (no) chrome, less bath tanning, less salt preservation of raw hides or natural preservation.In 1968, Xinxing Tannery in Shanghai, China first applied the enzymatic unhairing process to the production of pig leather, and combined with the pollution-free and less polluting tanning process, it reduced the environmental pollution of tanning wastewater.
Modern leather production
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Modern leather production has developed from the traditional three processing steps of preparation, tanning and finishing to two stages of dry and wet processing (see tanning).Wet processing begins to be separated from traditional tanneries. Factories are set up near the origin of raw hides or slaughterhouses to process raw hides and tan them into wet blue leather or wet white leather.Traditional tanneries only carry out dry processing and process wet blue leather or wet white leather into finished leather, which not only saves salt for preservation of raw leather, reduces pollution, but also improves the quality of finished leather.On the basis of component standardization and production assembly, modern leather shoe manufacturing implements small batch and multi variety production to adapt to changes in market demand.Leather and fur clothing are becoming more fashionable, and other leather products are developing in the direction of novel modeling, reasonable structure, multiple functions and matching with clothing.
With the shortage of raw hides, the appreciation of labor force value, and the increasingly strict requirements for environmental protection, the distribution, product structure and trade environment of the world leather industry are changing.Developed countries are committed to the production of high value-added products, while developing countries have begun to shift from raw hides to semi-finished products and manufactured products.All countries in the world are making full use of their raw leather resources, paying attention to scientific research, strengthening production management, and producing beautiful leather products with a wide range of varieties.
