34th China Fur & Leather Products Fair 2008
From: 15th January, to 18th January, 2008
Venue: China International Exhibition Centre (Bejing)
City: Beijing
Organisers Website: Fur & Fair http://www.fur-fair.com
The 103rd China Import and Export Fair
From: 15th April, to 20th April, 2008
Venue: China Import and Export Fair (Pazhou) Complex
City: Guangzhou
Organisers Website: http://www.cantonfair.org.cn/en/
The 7th China Dongguan International Fair for Shoes, and Leather Goods Manufacturing Technology and Material
From: 16th April, to 18th April 2008
Venue: Dongguan - Houjie
City: Dongguan
Organisers Website: http://www.chinashoesexpo.com/
The 18th International Exhibition on Shoes & Leather Industry
From: 28th May, to 31th May, 2008
Venue: China Import and Export Fair (Pazhou) Complex
City: Guangzhou
Organisers Website: http://www.shoesleather-guangzhou.com/home.html
The 2nd Fashion Focus Guangzhou Int’l Fair on Leather products and Footwear
From: July 10th, to July 12th 2008
Venue: Guangzhou Jin Han Exhibition Center
City: Guangzhou
Organisers Website: http://www.good-exhibition.com/dgpj/shishangen/index.htm
All China Leather Exhibition (ACLE)
From: 3rd September to 5th September 2008
Venue: Shanghai New International Expo Centre
City: Shanghai
Organisers Website: http://www.aplf.com , http://www.china-leather.com , http://www.messe-duesseldorf.de
The 13th China (Wenzhou) International Leather Fair 2008
From: 24th September, to 26th September 2008
Venue: Wenzhou Int’l Convention & Exhibition Center P.R.China
City: Wenzhou
Organisers Website: http://www.donnor.com/leather/fair/index.asp
The 104th China Import and Export Fair
From: 15th October – to 6th November, 2008
Venue: China Import and Export Fair (Pazhou) Complex
City: Guangzhou
Organisers Website: http://www.cantonfair.org.cn/en/
Compiled By Annabella Fashion Limited
Last Update: 03rd of June, 2008
6/04/2008
Leather Trade Associations
Europe
Italy
Aimpes
Camera Nazionale Della Moda Italiana
Assomac
AgricaLeather
France
Federation francaise de la maroquinerie
CTC (Centre Technique du Cuir)
Syndicat General des Cuirs et Peaux
UK
Leather Technology Center
British Travelgoods and Accessories Association
Society of Leather Technologists and Chemists
Germany
Verband der Deutschen Lederindustrie e.V.
Deutscher Pelzverband eV
Bundesverband Lederwaren und Kunststofferzeugnisse e.V.
Spain
Asociacion Espanola de Fabricantes de Marroquineria, Articulos de Viaje y Afines
Spanish Leather Chemists Association
Portugal
Portuguese Leather Association
Switzerland
International Union of Leather Technologists & Chemists Societies
The Netherlands
Dutch Federation of Tanners
Turkey
Turkish Leather Technologists and Chemists Society
Istanbul Textile and Apparel Exporters' Association
Albania
Albanian Leather/ Footwear Industry
Greece
Association of Greek Furriers
Slovakia
Association of Slovanian Leather and Shoe Industries
Russia
The Union of Russian Tanners
Americas
USA
Travel Goods Association
American Apparel and Footwear Association
American Leather Chemists Association
The United States Hide, Skin and Leather Association
Brasil
Abrameq
Argentina
Argentine Association of Leather Industry Technicians and Chemists
Asia
India
Council for Leather Exporters
Indian Leather Products Association
Vietnam
Vietnam Leather & Footwear Association
China
China Leather Association
Hong Kong
Hong Kong Hide & Leather Traders Association
Bangladesh
Leathergoods & Footwear Manufacturers & Exporters Association of Bangladesh
Syria
Arab Union for Leather Industries
Iran
Association of Leather Producers and Exporters of East-Azarbaijan
Africa
East Africa
Eastern & Southern Africa Leather Industries Association
Morocco
Moroccan Federation of Leather Industries
South Africa
National Ostrich Processors of South Africa
Ethyopia
Ethiopian Leather Industries Association
Oceania
Australia
The Australian Hide, Skin & Leather Exporters Association Ltd
New Zealand
Leather and Shoe Research Association
Italy
Aimpes
Camera Nazionale Della Moda Italiana
Assomac
AgricaLeather
France
Federation francaise de la maroquinerie
CTC (Centre Technique du Cuir)
Syndicat General des Cuirs et Peaux
UK
Leather Technology Center
British Travelgoods and Accessories Association
Society of Leather Technologists and Chemists
Germany
Verband der Deutschen Lederindustrie e.V.
Deutscher Pelzverband eV
Bundesverband Lederwaren und Kunststofferzeugnisse e.V.
Spain
Asociacion Espanola de Fabricantes de Marroquineria, Articulos de Viaje y Afines
Spanish Leather Chemists Association
Portugal
Portuguese Leather Association
Switzerland
International Union of Leather Technologists & Chemists Societies
The Netherlands
Dutch Federation of Tanners
Turkey
Turkish Leather Technologists and Chemists Society
Istanbul Textile and Apparel Exporters' Association
Albania
Albanian Leather/ Footwear Industry
Greece
Association of Greek Furriers
Slovakia
Association of Slovanian Leather and Shoe Industries
Russia
The Union of Russian Tanners
Americas
USA
Travel Goods Association
American Apparel and Footwear Association
American Leather Chemists Association
The United States Hide, Skin and Leather Association
Brasil
Abrameq
Argentina
Argentine Association of Leather Industry Technicians and Chemists
Asia
India
Council for Leather Exporters
Indian Leather Products Association
Vietnam
Vietnam Leather & Footwear Association
China
China Leather Association
Hong Kong
Hong Kong Hide & Leather Traders Association
Bangladesh
Leathergoods & Footwear Manufacturers & Exporters Association of Bangladesh
Syria
Arab Union for Leather Industries
Iran
Association of Leather Producers and Exporters of East-Azarbaijan
Africa
East Africa
Eastern & Southern Africa Leather Industries Association
Morocco
Moroccan Federation of Leather Industries
South Africa
National Ostrich Processors of South Africa
Ethyopia
Ethiopian Leather Industries Association
Oceania
Australia
The Australian Hide, Skin & Leather Exporters Association Ltd
New Zealand
Leather and Shoe Research Association
Leather Terminology
Leather Terminology
- Aniline Finish: Skins are drum-dyed for a soft, smooth feel. They are usually coated with protein, resin, lacquer, or can be waxed.
- Distressed: Buffing surface to create uneven coloration and markings for a weathered look
Glazed Finish: Surface is polished to a high luster by pressurized glass or steel rollers
- Grain: Refers to the outer surface, markings or the patterns on the leather's surface
Leather: A generic term used for all kinds of tanned animal hides or skins
- Metallic: Metallic color applied during the tanning process for a lustrous appearance
- Napa: Commonly refers to the surface or top grain of any soft leather hide
- Patent: Heavily finished to give a highly lustrous, baked-enamel type appearance
- Pearlized: Spray-on finish giving pearlized effect
- Shearling: Natural lamb pelts with the leather side often suede and worn on the outside
- Split: When a thick hide is split, the term refers to the top surface that looks like suede but is not as soft
- Suede: Leathers that are finished by buffing the underside of a hide to produce a velvet-like nap
- Unbuckle: Lightly buffed top grain to a very fine nap that appears smoother than suede
For more terms please refer to the Dictionnary of Leather Terms: http://www.iultcs.org/leather_terms/a.asp
http://www.ab-corporategifts.com/
- Aniline Finish: Skins are drum-dyed for a soft, smooth feel. They are usually coated with protein, resin, lacquer, or can be waxed.
- Distressed: Buffing surface to create uneven coloration and markings for a weathered look
Glazed Finish: Surface is polished to a high luster by pressurized glass or steel rollers
- Grain: Refers to the outer surface, markings or the patterns on the leather's surface
Leather: A generic term used for all kinds of tanned animal hides or skins
- Metallic: Metallic color applied during the tanning process for a lustrous appearance
- Napa: Commonly refers to the surface or top grain of any soft leather hide
- Patent: Heavily finished to give a highly lustrous, baked-enamel type appearance
- Pearlized: Spray-on finish giving pearlized effect
- Shearling: Natural lamb pelts with the leather side often suede and worn on the outside
- Split: When a thick hide is split, the term refers to the top surface that looks like suede but is not as soft
- Suede: Leathers that are finished by buffing the underside of a hide to produce a velvet-like nap
- Unbuckle: Lightly buffed top grain to a very fine nap that appears smoother than suede
For more terms please refer to the Dictionnary of Leather Terms: http://www.iultcs.org/leather_terms/a.asp
http://www.ab-corporategifts.com/
Leather Items Maintenance - FAQ
- What should I do when leather gets rain or salt from the streets on them?
Promptly remove salt deposits by sponging with clear water, then allow wet or damp leather items to air-dry naturally, away from any heat source. You can then treat most items with a specially formulated leather conditioner to renew flexibility while suede can be brushed with a terry towel to restore its look.
- Does leather lose its shape?
If not cared for properly, the skins in your garment can stretch or sag. Leather jackets and shirts should be hung on wide or padded hangers to best maintain their shape. Shoe and boot trees keep footwear looking good and handbags will look better longer when stuffed with white tissue paper.
- How should I store my leathers?
A dark closet that is neither too dry nor too humid is an ideal storage place. When putting garments away for the season, always place them in breathable covers, never plastic, which can dry out the leather.
- What kinds of products can be used to keep my leather looking great?
Be sure to choose products meant for your item. Carefully read and follow the instructions for best results. Never use household products, waxes, silicone or any other preparations that impair the leather's ability to breathe.
- My leather coat became wrinkled during travel. Can it be fixed?
It can. Most wrinkles will hang out on their own although it is perfectly safe to iron leather by carefully following these instructions. Simply set iron on its rayon setting, use heavy brown wrapping paper as a pressing cloth on the right side of the item and iron. Covering one section at a time while always keeping the iron moving, wrinkles should come right out.
- Are there any common things that can damage leather?
Perfumes, hair spray and your natural body oils are a few things that, over time, can discolor or damage leather. You should avoid spraying perfumes or hair spray while wearing your garment and a scarf at the neckline will help keep hair and body oil away from the collar.
- The hem of my favorite leather skirt has come loose. Can I fix it myself?
You can. Small areas can be fixed with a tiny amount of rubber cement. For bigger jobs consult your local leather care professional.
- I had my leather jacket professionally cleaned and the color changed. Is this normal?
As a matter of fact it is. Leather is a natural product and you can never determine exactly how it will react to the cleaning process. An recommended leather cleaner will clean the garment and then restore the essential oils that were lost during the procedure. Since the cleaner can never exactly match the method that was originally used when your garment was created, the result will sometimes be a slight change in color or texture. For this reason it is important to clean matching garments at the same time.
http://www.ab-corporategifts.com/
Promptly remove salt deposits by sponging with clear water, then allow wet or damp leather items to air-dry naturally, away from any heat source. You can then treat most items with a specially formulated leather conditioner to renew flexibility while suede can be brushed with a terry towel to restore its look.
- Does leather lose its shape?
If not cared for properly, the skins in your garment can stretch or sag. Leather jackets and shirts should be hung on wide or padded hangers to best maintain their shape. Shoe and boot trees keep footwear looking good and handbags will look better longer when stuffed with white tissue paper.
- How should I store my leathers?
A dark closet that is neither too dry nor too humid is an ideal storage place. When putting garments away for the season, always place them in breathable covers, never plastic, which can dry out the leather.
- What kinds of products can be used to keep my leather looking great?
Be sure to choose products meant for your item. Carefully read and follow the instructions for best results. Never use household products, waxes, silicone or any other preparations that impair the leather's ability to breathe.
- My leather coat became wrinkled during travel. Can it be fixed?
It can. Most wrinkles will hang out on their own although it is perfectly safe to iron leather by carefully following these instructions. Simply set iron on its rayon setting, use heavy brown wrapping paper as a pressing cloth on the right side of the item and iron. Covering one section at a time while always keeping the iron moving, wrinkles should come right out.
- Are there any common things that can damage leather?
Perfumes, hair spray and your natural body oils are a few things that, over time, can discolor or damage leather. You should avoid spraying perfumes or hair spray while wearing your garment and a scarf at the neckline will help keep hair and body oil away from the collar.
- The hem of my favorite leather skirt has come loose. Can I fix it myself?
You can. Small areas can be fixed with a tiny amount of rubber cement. For bigger jobs consult your local leather care professional.
- I had my leather jacket professionally cleaned and the color changed. Is this normal?
As a matter of fact it is. Leather is a natural product and you can never determine exactly how it will react to the cleaning process. An recommended leather cleaner will clean the garment and then restore the essential oils that were lost during the procedure. Since the cleaner can never exactly match the method that was originally used when your garment was created, the result will sometimes be a slight change in color or texture. For this reason it is important to clean matching garments at the same time.
http://www.ab-corporategifts.com/
Leather Production - Managing Quality
MANAGING QUALITY
The dictionary definition of quality in any product is that it is the characteristic property of that product, and a measure of its standard of excellence of the product.
Quality in a finished leather, or leather product, means an attractive appearance, a long lasting material and a high standard of workmanship. It is related to price and a good quality relates to a higher price compared with a lower standard of quality. The assessment of value, for a certain quality at a certain price, depends on the customer. However, often they are not aware of differences in leather quality.
Leather production starts with a material, which is already below the top quality standard in surface appearance, in different degrees. All of the variables should be related to the raw material price. Processing aims to improve the appearance, and so add value. This will involve more costs for the lower grades, compared with the lower costs for the top quality raw material, because much more work is needed to produce an acceptable appearance. For example, the top quality aniline leather has the thin, transparent coloured finish film. Lower qualities need to have covering pigment films, which cover and disguise defects, before they can have an approximately similar aniline appearance. The focus on upgrading the lower priced material has been most successful in the supply of lower priced footwear and leather goods. Of course, it still does not really look like the top quality, but the lower price compensates for this and makes it attractive to the customer from the value aspect. The customer market has to be selected for the particular raw material and production potential available from the facilities.
STANDARDS & PROCESS CONTROLS
Leather needs to have a consistent appearance, with a consistent chemical and physical composition. It also has to behave consistently in the manufacture of the product, for example in the lasting and shaping of a shoe. Customers need to have confidence that the tannery is in control and will be a reliable supplier for quality and delivery. It is always important, but especially for exports from an industry in a developing country, where a good reputation has to be earned and maintained.
To manage quality, control of the relevant property is needed to make this reliable product from a variable raw material. Many of the characteristics of leather are subjective (appearance, feel and softness) but some are objective (thickness and colour). A quality standard does not truly refer to perfection but to an agreed balance between the customer’s need and the supplier’s capability, which may be described in the sales contract and may incorporate a sample pattern for colour, feel or type of appearance. It is also involves mutual understanding and agreement. For raw hides and skins, the standard may be the proportion of different grades of sound material, with grades based on the potential final value of the leather produced. The customer needs to have the consistency and reliability of a uniform supply, within an agreed tolerance.
Once the different standards are established, plans are made to control these at different process stages, by checks and inspections. It is known that process conditions need to be consistent to achieve reliability. Consequently, recording systems are needed, depending on the product required, to achieve the desired reproducibility. The whole manufacturing system can be developed to ensure that each employee plays a part in ensuring that each operation done is a correct step to produce the standard required. The controls need not be complicated but they should begin early in the processing and be maintained consistently.
Contributed By Mr. Woodley, Michael International Consultant May, 2007
http://www.ab-corporategifts.com
The dictionary definition of quality in any product is that it is the characteristic property of that product, and a measure of its standard of excellence of the product.
Quality in a finished leather, or leather product, means an attractive appearance, a long lasting material and a high standard of workmanship. It is related to price and a good quality relates to a higher price compared with a lower standard of quality. The assessment of value, for a certain quality at a certain price, depends on the customer. However, often they are not aware of differences in leather quality.
Leather production starts with a material, which is already below the top quality standard in surface appearance, in different degrees. All of the variables should be related to the raw material price. Processing aims to improve the appearance, and so add value. This will involve more costs for the lower grades, compared with the lower costs for the top quality raw material, because much more work is needed to produce an acceptable appearance. For example, the top quality aniline leather has the thin, transparent coloured finish film. Lower qualities need to have covering pigment films, which cover and disguise defects, before they can have an approximately similar aniline appearance. The focus on upgrading the lower priced material has been most successful in the supply of lower priced footwear and leather goods. Of course, it still does not really look like the top quality, but the lower price compensates for this and makes it attractive to the customer from the value aspect. The customer market has to be selected for the particular raw material and production potential available from the facilities.
STANDARDS & PROCESS CONTROLS
Leather needs to have a consistent appearance, with a consistent chemical and physical composition. It also has to behave consistently in the manufacture of the product, for example in the lasting and shaping of a shoe. Customers need to have confidence that the tannery is in control and will be a reliable supplier for quality and delivery. It is always important, but especially for exports from an industry in a developing country, where a good reputation has to be earned and maintained.
To manage quality, control of the relevant property is needed to make this reliable product from a variable raw material. Many of the characteristics of leather are subjective (appearance, feel and softness) but some are objective (thickness and colour). A quality standard does not truly refer to perfection but to an agreed balance between the customer’s need and the supplier’s capability, which may be described in the sales contract and may incorporate a sample pattern for colour, feel or type of appearance. It is also involves mutual understanding and agreement. For raw hides and skins, the standard may be the proportion of different grades of sound material, with grades based on the potential final value of the leather produced. The customer needs to have the consistency and reliability of a uniform supply, within an agreed tolerance.
Once the different standards are established, plans are made to control these at different process stages, by checks and inspections. It is known that process conditions need to be consistent to achieve reliability. Consequently, recording systems are needed, depending on the product required, to achieve the desired reproducibility. The whole manufacturing system can be developed to ensure that each employee plays a part in ensuring that each operation done is a correct step to produce the standard required. The controls need not be complicated but they should begin early in the processing and be maintained consistently.
Contributed By Mr. Woodley, Michael International Consultant May, 2007
http://www.ab-corporategifts.com
Leather Production - Production Chain
PRODUCTION CHAIN
The industry process chain may be split into 6 main production stages and the product at each stage has the potential to be traded internationally. The relative increase in added value and potential commercial profit can be seen as the raw material passes through the various stages of the chain.
1. Raw material
The raw material comes from cattle hides, and from the skins of other animals. It is biodegradable and loses structure and value if it is not preserved correctly and promptly after slaughter. This is normally by salting or drying. The hides and skins need to be without decay, cuts or damage, and of good shape.
In contrast to the well-developed quality and market standards in developed countries, this is critical factor in developing countries, which persist in primitive systems encouraging informal trade and preventing the full potential value being obtained.
A proposed African scheme is well designed but not implemented yet. ESALIA/CFC sorting standards classify ground, ball and smoked dried hides and skins as rejects; the lowest of 4 acceptable skin selections has defects up to 40% of skin area; above this 40% means that the skins are total rejects, together with untrimmed or poorly trimmed skins. Hides also have 4 grades, with the lowest grade having defects up to 50% of the hide area; above this 50% is a total rejects. "Fallen" hides and skins originate from animals dying naturally and are considered as reject material, unsuitable for processing. After soaking and hair removal in alkaline liming, they are pickled.
2. Pickle
The pickled state is a wet, acidic condition and a preparation for tanning the leather. "Pickled" leather is a traditional product, a commodity for export shipment of skins, which allows the importing tanner the widest choice in tanning materials. All other semi- processed materials have already been tanned and offer less flexibility regarding their potential final product.
3. Wet Blue & Wet White
Wet blue, and Wet White, comes from the tanned state. Tanning gives permanence to the protein and stops further decay. The "blue" refers to the more general chromium tannage, compared with the newer chrome- free white tannage. (Vegetable tannage is an older process, and still used for some upholstery, belts and sole leather. The natural colour of vegetable tannage is brown. It is not traded in the wet condition.)
"Wet blue" leather is well-established as a commodity for international trading, because of the widespread use of chrome tanning. As such it is price sensitive, provided quality and reliability is established. As stated above, this form of export is increasingly preferred by importers, because it arrives without risk of transmittable diseases, a factor of concern with unprocessed hides and skins. It also has the advantage that all processes, which cause the most damage to the environment, have already been carried out in the exporting country. A further advantage is that importers can specify the range of the quality selection they need to buy – which conversely means that the exporter has to consider the sale of the other grades.
"Wet white" leather is of increasing interest where chromium is to be avoided – for example, for automotive upholstery. These FOC (‘free of chrome’) leathers are expected to experience increasing demand in the future, as environmental concern and legislation grows.
After tanning, the wet hides and skins are usually dyed and further treated with softening chemicals. After drying, their condition is known as the "crust". This is the first point in the process at which they are actually dry.
4. Crust
Crust leather is dry and is easier to ship. It is also easier to see the quality of the surface appearance for grading and value judgements. It is ready for further processing, either for more wet work (retanning and dyeing), or for direct dry finishing.
It may be pure vegetable tanned crust, or a combination of chrome, synthetic and vegetable tannage. It is an advantage to develop such a product for a specific customer, who provides the guidance; otherwise it is much more difficult.
Properties such as tightness, softness and the response to finishing operations are critical in making a good product and demand greater technical ability.
Although some countries propose that exports should only be allowed as crust, or at an even later stage (in order to add value), the results have often been negative. The hides and skins from individual animals are different, and unique in their appearance, reflecting the animal's history. The classification of relative quality is the key operation in a tannery, and is carried out at several stages in the process.
The profitability of the whole business depends on using the grades for the appropriate products, and making an overall profit from all the raw material used. There should be no inventory without a potential sale"dead stock". After sorting for quality – surface appearance, feel, thickness – finishing coats of colour are applied, to improve the appearance and serviceability of the hides. These qualities are all customer-specific.
5. Finished leather
Finished leather has the potential to add even more value and to provide much better earnings, but it also is much more difficult to achieve successfully. Compared with wet blue leather, which can be made into a number of final products, finished leather has to be made in a specific type, colour and thickness for each specific product (and usually for each specific customer). There is no room for error to achieve a profit, and it is essential to develop finished leathers for each grade of crust material. The necessary semi-processed hides and skins (stages 2 to 4) are taken from the normal production line, according to the demands of the market. Specialist processing equipment is involved through all the stages.
6. Finished leather products
Finished leather products are made from the different leathers into a wide range of products. The major use of cattle hides is for the uppers of heavier leather shoes, but there are increasing demands for furniture and automotive upholstery. Skins are used for lighter shoes, leather clothing and gloves. Large and small leather goods, from suitcases and golf bags, to wallets and briefcases, are made from both hides and skins. Each finished leather product has its own specific leather requirements.
Contributed By Mr. Woodley, Michael International Consultant May, 2007
http://www.ab-corporategifts.com
The industry process chain may be split into 6 main production stages and the product at each stage has the potential to be traded internationally. The relative increase in added value and potential commercial profit can be seen as the raw material passes through the various stages of the chain.
1. Raw material
The raw material comes from cattle hides, and from the skins of other animals. It is biodegradable and loses structure and value if it is not preserved correctly and promptly after slaughter. This is normally by salting or drying. The hides and skins need to be without decay, cuts or damage, and of good shape.
In contrast to the well-developed quality and market standards in developed countries, this is critical factor in developing countries, which persist in primitive systems encouraging informal trade and preventing the full potential value being obtained.
A proposed African scheme is well designed but not implemented yet. ESALIA/CFC sorting standards classify ground, ball and smoked dried hides and skins as rejects; the lowest of 4 acceptable skin selections has defects up to 40% of skin area; above this 40% means that the skins are total rejects, together with untrimmed or poorly trimmed skins. Hides also have 4 grades, with the lowest grade having defects up to 50% of the hide area; above this 50% is a total rejects. "Fallen" hides and skins originate from animals dying naturally and are considered as reject material, unsuitable for processing. After soaking and hair removal in alkaline liming, they are pickled.
2. Pickle
The pickled state is a wet, acidic condition and a preparation for tanning the leather. "Pickled" leather is a traditional product, a commodity for export shipment of skins, which allows the importing tanner the widest choice in tanning materials. All other semi- processed materials have already been tanned and offer less flexibility regarding their potential final product.
3. Wet Blue & Wet White
Wet blue, and Wet White, comes from the tanned state. Tanning gives permanence to the protein and stops further decay. The "blue" refers to the more general chromium tannage, compared with the newer chrome- free white tannage. (Vegetable tannage is an older process, and still used for some upholstery, belts and sole leather. The natural colour of vegetable tannage is brown. It is not traded in the wet condition.)
"Wet blue" leather is well-established as a commodity for international trading, because of the widespread use of chrome tanning. As such it is price sensitive, provided quality and reliability is established. As stated above, this form of export is increasingly preferred by importers, because it arrives without risk of transmittable diseases, a factor of concern with unprocessed hides and skins. It also has the advantage that all processes, which cause the most damage to the environment, have already been carried out in the exporting country. A further advantage is that importers can specify the range of the quality selection they need to buy – which conversely means that the exporter has to consider the sale of the other grades.
"Wet white" leather is of increasing interest where chromium is to be avoided – for example, for automotive upholstery. These FOC (‘free of chrome’) leathers are expected to experience increasing demand in the future, as environmental concern and legislation grows.
After tanning, the wet hides and skins are usually dyed and further treated with softening chemicals. After drying, their condition is known as the "crust". This is the first point in the process at which they are actually dry.
4. Crust
Crust leather is dry and is easier to ship. It is also easier to see the quality of the surface appearance for grading and value judgements. It is ready for further processing, either for more wet work (retanning and dyeing), or for direct dry finishing.
It may be pure vegetable tanned crust, or a combination of chrome, synthetic and vegetable tannage. It is an advantage to develop such a product for a specific customer, who provides the guidance; otherwise it is much more difficult.
Properties such as tightness, softness and the response to finishing operations are critical in making a good product and demand greater technical ability.
Although some countries propose that exports should only be allowed as crust, or at an even later stage (in order to add value), the results have often been negative. The hides and skins from individual animals are different, and unique in their appearance, reflecting the animal's history. The classification of relative quality is the key operation in a tannery, and is carried out at several stages in the process.
The profitability of the whole business depends on using the grades for the appropriate products, and making an overall profit from all the raw material used. There should be no inventory without a potential sale"dead stock". After sorting for quality – surface appearance, feel, thickness – finishing coats of colour are applied, to improve the appearance and serviceability of the hides. These qualities are all customer-specific.
5. Finished leather
Finished leather has the potential to add even more value and to provide much better earnings, but it also is much more difficult to achieve successfully. Compared with wet blue leather, which can be made into a number of final products, finished leather has to be made in a specific type, colour and thickness for each specific product (and usually for each specific customer). There is no room for error to achieve a profit, and it is essential to develop finished leathers for each grade of crust material. The necessary semi-processed hides and skins (stages 2 to 4) are taken from the normal production line, according to the demands of the market. Specialist processing equipment is involved through all the stages.
6. Finished leather products
Finished leather products are made from the different leathers into a wide range of products. The major use of cattle hides is for the uppers of heavier leather shoes, but there are increasing demands for furniture and automotive upholstery. Skins are used for lighter shoes, leather clothing and gloves. Large and small leather goods, from suitcases and golf bags, to wallets and briefcases, are made from both hides and skins. Each finished leather product has its own specific leather requirements.
Contributed By Mr. Woodley, Michael International Consultant May, 2007
http://www.ab-corporategifts.com
Leather Production - Finishing
FINISHING
The object of finishing leather is to improve its serviceability by protecting it from damage by water, soil and mechanical action. At the same time, it is also improving the cutting area. Finishing adds value by improving the surface appearance so much that the leather becomes attractive to look at and attractive to touch and feel; any of the surface defects below the finish cannot be seen or considered by the buyer, or the ultimate user of the leather product. Experience and an appreciation of colour effects are needed to achieve the desired results. The technician often has to be able to develop a finished look to match a competitive sample in a short time.
Finishing can modify the shade, gloss and handle of the leather, improve its physical properties (such as its light and rub fastness), and hide any defects or irregular appearance. It is heavily applied to corrected grain leathers and to splits in order to imitate full grain leathers and often used to obtain fashion effects on all leathers.
The lowest grades of leather need the most finishing work, compared with the minimum amount of finishing for the best grades. At the same time, the best grades sell at the highest price and the lowest grades at the lowest price. With such a difference in the finishing costs for these extremes of sales prices, it can be seen that the top quality traditionally has a much higher profit margin than the bottom quality. It is naturally essential that all grades and qualities are eventually sold, although it will be to different buyers.
Aniline leather is considered the top quality because the transparent finish does not cover any of the surface full grain. Originally, it referred to leather without any finish, which had been drum dyed with aniline dyestuffs and this was the only colouring it received. It should now mean that there are no covering pigments used in the finishing films; therefore, the leather has to be almost without defects. Most finishes for a classic appearance on leather do have some covering property, but try to produce the aniline effect by incorporating dyestuffs at some stage. The shortage of high quality raw material means that a lot of progress has been made to upgrade the lower grades, by improving the cutting value and surface appearance. The section on upgrading shows some possibilities.
All the individual operations are options according to the finished article and the quality of the crust to be finished. Normally, there are several layers of finish applied and the constitution varies between the different coats - base coats, top coats and pigmented coats. Adhesion to the leather and inter-coat adhesion is essential in wet and dry conditions. The flexibility of films has to match the flexibility of the leather. For example, there is difference in leather for garment, glove, shoe or upholstery. The lower films in a finish are more flexible with good adhesion to the base, compared with the upper films, which provide the protective surface by being harder. The top coat needs to be the most resistant to damage. The film properties are built up progressively in the finish, with different formulations for base, intermediate and top coats.
The table gives a general scheme for better full grain grades with more pigment being used to cover problem areas, assisted by some printing (embossing) with hair-cell to give an even grain appearance. Corrected leathers have more finish coats and need attention to impregnate and seal the buffed surface.
There is a large variety of finish formulations, which are mainly water based. There are different colouring materials, including inorganic and organic pigments, dyestuffs and waxes, feel modifiers, matting agents, fillers, polymers of all types, casein, dispersing agents, plasticizers, diluents. These are applied to the leather in several coats; starting with higher rates such as 20 grams per square foot, and ending lighter as 5 grams.
Care has to be taken in handling the leather so that the surface is kept as flat as possible during all the finish operations. Creases and folds reduce the finish effect and certainly lose value in the finished leather.
1. APPLICATION always involves waste finishes as liquid or spray
Hand padding and spraying have been almost replaced by roller and curtain coaters and spraying machines in all medium and large productions. There are exceptions for special leathers, developments and samples. The costs of finishing small batches are high if the large amount of finish needed to prime the machines has to be eventually discarded. Controls on spraying machines reduce waste and are important to reduce and control toxic emissions from spray exhausts. This prevents atmospheric pollution from Volatile Organic compounds (VOC). Conveyor drying and stacking machines are linked into the finishing lines.
2. UPGRADING
The object is to improve the value of the lower quality raw material, including splits. It includes the following possibilities:
- A complete film, with embossing or grain pattern, transferred from a previously coated release papers. Ideal for splits and gives high abrasion resistance with a good appearance. They can be used from shoes to leather goods and smaller parts of car upholstery.
- Laminated film, glued to splits. Used for sport shoes and a wide range of fashion effects. A major use is for leather goods and belts.
- High coverage finishes. A thin film with reduced transparency gives a natural appearance and can be used on full grain without the risk of overloading a sensitive grain.
- Stucco fillers. These are a type of plaster and are applied by hand, or roller coater after impregnation and re-buffing. The surface becomes more even as the small scars and scratches are physically filled. After application, leather is re-buffed and finished conventionally. Needs care to avoid poor lasting and low flex resistance.
- Cationic products can give good base sealing because they are the opposite charge to the subsequent normal anionic finishes. It prevents absorption and seals defects.
- Foam finishing. The foam is produced in a finishing mixture by a special pump and applied from roller coaters. As the foam does not penetrate deeply, it maintains the softness of the leather. The trapped air results in a thicker film, compared with a film of equivalent solids content from a roller coater. Consequently, it covers well and has a natural appearance. It also embosses well with good print retention and flexibility. The most common use is on splits and heavily buffed leathers.
- Fine buffing, polishing, the use of sandblast and hair cell grain embossing plates below the finish, all are disguising the basic problem areas.
- Roller coaters are an important finishing machine, with an increasing variety of uses as both the mechanical performance and the finish formulations are developed in different directions. The leather has to be flat, and firm enough to pass through the rollers without damage. Concentrated finishes can be applied cleanly to low quality leathers. Like curtain coaters, the viscosity needs to be regulated and polymer emulsions need to be mechanically stable.
- Reverse roller coating is especially good for white leathers because fewer coats are needed and it is easier to keep the leather clean. Finishing white leather otherwise is a difficult operation.
- Synchro-roller coating, also known as direct forward coating, is for soft full grain side or on sheep nappa. It applies a thick soft film, which does not firm the leather but does cover defects and seal damaged grain.
- Gravure printing by engraved rollers and the surface tipping of embossed or milled leather produces unique surface designs and disguises defects.
- Fashion effects such as rub off, oily pull up, semi-aniline (transparent coloured films on a covering base film) and other optical effects are all used to distract the eye from the defective area.
- Dry milling breaks up the surface appearance and hides the defects underneath.
- Finishes with special properties command a special price, and needs a specific approach. The special property becomes more critical than some natural defects. Such leathers would include scuff resistant, water repellent, washable and dry cleanable finishes.
3. BUFFING and the production of waste as dry tanned dust
The object is to obtain a more even surface for finishing on low quality leather, where the grain has defects, which cannot be covered uniformly. The grain surface is buffed off by a fast revolving cylinder, covered with abrasive paper. This reveals an even surface with a suitable base for heavier finishing coats. Buffing papers are graded by the size of the grit, so that 80-100 are very rough, and would only be used for the start of producing a suede nap appearance. 150-220 grits are finer and suitable to start buffing a corrected grain leather. Finer papers are 280,320 and 360. A buffing sequence is normally at least 2 different grades on the grain- say 220 and 320. Buffing too deep gives too much absorbency and penetration of the finish, which makes the grain open and the surface unable to be filled by the finish. The final buffed surface has to have even absorption, so it is often necessary to buff the thinner belly areas with a separate cut, with a small width machine or feeding in a different direction towards it. Normal buffing is done from butt to shoulder, but it is also done in both directions. The flesh side of full and corrected grain is often buffed as required. Buffing cylinders revolve at about 1000 rpm and the machines have to be connected to efficient dust extraction systems. The type of retannage affects the buffing properties, in that there has to be surface filling of the grain to allow the degree of buffing. Vegetable or replacement syntans are preferred.
4. DUST REMOVAL - with the collection of the dust for disposal
After each buffing operation, the leather passes on the conveyor of an air-blast de-dusting machine underneath a thin jet of compressed air, which clears the dust by blowing it into the attached extraction system. It is important that the surface is absolutely clean, and free of dust, for proper finishing and appearance.
5. IMPREGNATE
This operation is an option and has the object to reduce the looseness of the leather structure by making it tighter and firmer, and to improve the selection. It is used on leather, which will not be suitable as full grain, and has been buffed. This buffing needs to be done so that the whole surface has an even absorption. If leather is given a relatively heavy finish coat, the appearance is often unsatisfactory because it does not look natural and has a poor break. To avoid this, corrected grain leathers are sometimes impregnated with penetrating dispersions. These must penetrate deeply and stick the looser layers of the structure together. About 20-30 grams of mixture are applied per square foot, which has to be done by curtain coater, roller machine or airless spray. After standing overnight to allow maximum penetration, the leather is dried flat, preferably on a lower temperature vacuum machine. The surface is then either polished, if it is full grain, or rebuffed, if corrected, with a fine 400-grit paper and de-dusted. The result is a smooth sealed surface ready for further finishing.
6. DYE STAIN
Spray staining with liquid dye solutions is done to colour the surface of un-dyed leather and to level drum dyed shades. It is used for all grades of leather.
7. POLISH
This is done with a fast revolving cylinder made of stone, felt or resin roller and used on all types
of hides and skins. It flattens the grain and softens the leather, with applications before, and between finishing coats.
8. BASE COAT
This is the first and the most important coat of finish because it has to provide the adhesion of the whole film to the actual leather. The composition is formulated to meet this priority. The polymers used are soft and flexible. The formulation will usually include some covering pigments and fillers, to hide as many defects as possible.
9. PIGMENT COAT
This is considered to be a main covering coat due to its pigment proportion at 100-150 grams per litre. It can be applied by pad, roller or spray. Later coats have reduced pigment levels to improve the natural appearance. Organic pigments are more natural than inorganic and can be used at 25 grams per litre, without affecting the transparent look. It should always look as natural as possible.
10. CONTRAST COAT
This transparent coloured coat contains dyestuffs, which is slightly darker than, and contrasts with the colour of, the covering base coat. The effect of this colour contrast is to appear as an aniline finish, with the clear dyed film disguising the pigmented look below it.
11. TOP COAT
The final coat has to protect the coloured film below and is important for the fastness properties of the film. It determines the final look and handle of the finish. Traditionally, it may be in solvent or low- solvent solution. Special cross-linking systems to cross-link acrylics and urethane films are now used to achieve the same properties without solvent emission being a problem.
12. PRESS
Pressing and ironing are intermediate and final operations in building up the finish film. The straight through heated rollers are preferable for productivity and maintaining leather softness. The hydraulic ram presses use heavier pressure to compress the fibre structure, and are essential for obtaining an effective embossing print.
13. GLAZE
Classic glazed kid is made by the original design machine with a glazing jack, usually of glass, which rubs the leather surface with a reciprocating action. The heat and pressure produced give a deep glaze effect, due to the protein binders and dyes, and gives a true aniline appearance. The machine principle is unchanged for many years and needs skilled operators. Although, there are safety concerns in the handling of the leathers, it does produce a unique appearance. The wet fastness is a problem. A rotary ironing machine gives the nearest alternative effect, and does not need the same amount of skill for operation. It is also used for hides.
14. DRY DRUM (MILL) AND TOGGLE - some dust produced from drum
This option of a fast revolving (20 rpm) dry drum is increasingly used to produce very soft leather with a relaxed surface appearance. It could be for upholstery, garments, or casual shoes. There are degrees of development, with dust extraction needed to clean any fibres from the atmosphere, and a moisturising spray injection. It can be done on crust leather without finish, split, suede or on finished leather, provided the finish film will withstand the mechanical action. Several hours running of the drum is often needed. The leather has to be toggled afterwards to restore the flat surface and the area.
15. FINAL SORT , and often trimming with production of dried waste finished leather pieces and
trimming
Here is the final quality check and assessment of the leather value, sorting into different grades. There is a limited amount of light trimming, where this improves the selection and allows an upgrade. This is another skilled operation and determines the financial balance of each production lot and the impression it makes on the customer. Any leather, which does not meet the standard required, has to be dealt with separately; in a different grade, reworked or rejected.
16. MEASURE
The area of the sorted leathers is measured, usually electronically on a horizontal conveyor. The accuracy of the machine needs to be checked on a daily basis with a template. The individual area of each piece can be stamped on it, together with a suitable code to identify the production lot and permit it to be traced.
17. PACK
It is important to maintain the finished appearance in packing so that the leather can arrive in the customer’s warehouse looking as attractive as it did when it was sorted in the tannery. It can be difficult to achieve this when there is a lot of handling in shipment. This normally means that some finished leather, sensitive to damage, is rolled with the grain surface on outside of the roll; others are placed grain to grain. Smaller skins are folded. The outermost piece is covered with a protective wrapper, which is then fixed tightly with a non-damaging tape or chord. It is important that the leathers are held tight to prevent any possible movement in travel. If feasible, small leathers are packed flat onto small pallets. It is important that any packing for individual rolls is permeable to avoid moisture being trapped during the time of shipment. Cartons provide the best protection against the handling in transit, with several rolls or bundles in each carton. A container shipment with cartons of leather packed by the tannery is ideal. It is essential that there should be no risk of damage from the weather. Wet, cold and heat all affect finishes and leathers.
18. DESPATCH FOR SHIPMENT
The documents for shipment need to show all information to conform to the original order and the production schedule of the tannery, to allow tracing and form the basis of future orders. These details also allow the tannery to check the financial contribution made by this production lot.
Contributed By Mr. Woodley, Michael International Consultant May, 2007
http://www.ab-corporategifts.com
The object of finishing leather is to improve its serviceability by protecting it from damage by water, soil and mechanical action. At the same time, it is also improving the cutting area. Finishing adds value by improving the surface appearance so much that the leather becomes attractive to look at and attractive to touch and feel; any of the surface defects below the finish cannot be seen or considered by the buyer, or the ultimate user of the leather product. Experience and an appreciation of colour effects are needed to achieve the desired results. The technician often has to be able to develop a finished look to match a competitive sample in a short time.
Finishing can modify the shade, gloss and handle of the leather, improve its physical properties (such as its light and rub fastness), and hide any defects or irregular appearance. It is heavily applied to corrected grain leathers and to splits in order to imitate full grain leathers and often used to obtain fashion effects on all leathers.
The lowest grades of leather need the most finishing work, compared with the minimum amount of finishing for the best grades. At the same time, the best grades sell at the highest price and the lowest grades at the lowest price. With such a difference in the finishing costs for these extremes of sales prices, it can be seen that the top quality traditionally has a much higher profit margin than the bottom quality. It is naturally essential that all grades and qualities are eventually sold, although it will be to different buyers.
Aniline leather is considered the top quality because the transparent finish does not cover any of the surface full grain. Originally, it referred to leather without any finish, which had been drum dyed with aniline dyestuffs and this was the only colouring it received. It should now mean that there are no covering pigments used in the finishing films; therefore, the leather has to be almost without defects. Most finishes for a classic appearance on leather do have some covering property, but try to produce the aniline effect by incorporating dyestuffs at some stage. The shortage of high quality raw material means that a lot of progress has been made to upgrade the lower grades, by improving the cutting value and surface appearance. The section on upgrading shows some possibilities.
All the individual operations are options according to the finished article and the quality of the crust to be finished. Normally, there are several layers of finish applied and the constitution varies between the different coats - base coats, top coats and pigmented coats. Adhesion to the leather and inter-coat adhesion is essential in wet and dry conditions. The flexibility of films has to match the flexibility of the leather. For example, there is difference in leather for garment, glove, shoe or upholstery. The lower films in a finish are more flexible with good adhesion to the base, compared with the upper films, which provide the protective surface by being harder. The top coat needs to be the most resistant to damage. The film properties are built up progressively in the finish, with different formulations for base, intermediate and top coats.
The table gives a general scheme for better full grain grades with more pigment being used to cover problem areas, assisted by some printing (embossing) with hair-cell to give an even grain appearance. Corrected leathers have more finish coats and need attention to impregnate and seal the buffed surface.
There is a large variety of finish formulations, which are mainly water based. There are different colouring materials, including inorganic and organic pigments, dyestuffs and waxes, feel modifiers, matting agents, fillers, polymers of all types, casein, dispersing agents, plasticizers, diluents. These are applied to the leather in several coats; starting with higher rates such as 20 grams per square foot, and ending lighter as 5 grams.
Care has to be taken in handling the leather so that the surface is kept as flat as possible during all the finish operations. Creases and folds reduce the finish effect and certainly lose value in the finished leather.
1. APPLICATION always involves waste finishes as liquid or spray
Hand padding and spraying have been almost replaced by roller and curtain coaters and spraying machines in all medium and large productions. There are exceptions for special leathers, developments and samples. The costs of finishing small batches are high if the large amount of finish needed to prime the machines has to be eventually discarded. Controls on spraying machines reduce waste and are important to reduce and control toxic emissions from spray exhausts. This prevents atmospheric pollution from Volatile Organic compounds (VOC). Conveyor drying and stacking machines are linked into the finishing lines.
2. UPGRADING
The object is to improve the value of the lower quality raw material, including splits. It includes the following possibilities:
- A complete film, with embossing or grain pattern, transferred from a previously coated release papers. Ideal for splits and gives high abrasion resistance with a good appearance. They can be used from shoes to leather goods and smaller parts of car upholstery.
- Laminated film, glued to splits. Used for sport shoes and a wide range of fashion effects. A major use is for leather goods and belts.
- High coverage finishes. A thin film with reduced transparency gives a natural appearance and can be used on full grain without the risk of overloading a sensitive grain.
- Stucco fillers. These are a type of plaster and are applied by hand, or roller coater after impregnation and re-buffing. The surface becomes more even as the small scars and scratches are physically filled. After application, leather is re-buffed and finished conventionally. Needs care to avoid poor lasting and low flex resistance.
- Cationic products can give good base sealing because they are the opposite charge to the subsequent normal anionic finishes. It prevents absorption and seals defects.
- Foam finishing. The foam is produced in a finishing mixture by a special pump and applied from roller coaters. As the foam does not penetrate deeply, it maintains the softness of the leather. The trapped air results in a thicker film, compared with a film of equivalent solids content from a roller coater. Consequently, it covers well and has a natural appearance. It also embosses well with good print retention and flexibility. The most common use is on splits and heavily buffed leathers.
- Fine buffing, polishing, the use of sandblast and hair cell grain embossing plates below the finish, all are disguising the basic problem areas.
- Roller coaters are an important finishing machine, with an increasing variety of uses as both the mechanical performance and the finish formulations are developed in different directions. The leather has to be flat, and firm enough to pass through the rollers without damage. Concentrated finishes can be applied cleanly to low quality leathers. Like curtain coaters, the viscosity needs to be regulated and polymer emulsions need to be mechanically stable.
- Reverse roller coating is especially good for white leathers because fewer coats are needed and it is easier to keep the leather clean. Finishing white leather otherwise is a difficult operation.
- Synchro-roller coating, also known as direct forward coating, is for soft full grain side or on sheep nappa. It applies a thick soft film, which does not firm the leather but does cover defects and seal damaged grain.
- Gravure printing by engraved rollers and the surface tipping of embossed or milled leather produces unique surface designs and disguises defects.
- Fashion effects such as rub off, oily pull up, semi-aniline (transparent coloured films on a covering base film) and other optical effects are all used to distract the eye from the defective area.
- Dry milling breaks up the surface appearance and hides the defects underneath.
- Finishes with special properties command a special price, and needs a specific approach. The special property becomes more critical than some natural defects. Such leathers would include scuff resistant, water repellent, washable and dry cleanable finishes.
3. BUFFING and the production of waste as dry tanned dust
The object is to obtain a more even surface for finishing on low quality leather, where the grain has defects, which cannot be covered uniformly. The grain surface is buffed off by a fast revolving cylinder, covered with abrasive paper. This reveals an even surface with a suitable base for heavier finishing coats. Buffing papers are graded by the size of the grit, so that 80-100 are very rough, and would only be used for the start of producing a suede nap appearance. 150-220 grits are finer and suitable to start buffing a corrected grain leather. Finer papers are 280,320 and 360. A buffing sequence is normally at least 2 different grades on the grain- say 220 and 320. Buffing too deep gives too much absorbency and penetration of the finish, which makes the grain open and the surface unable to be filled by the finish. The final buffed surface has to have even absorption, so it is often necessary to buff the thinner belly areas with a separate cut, with a small width machine or feeding in a different direction towards it. Normal buffing is done from butt to shoulder, but it is also done in both directions. The flesh side of full and corrected grain is often buffed as required. Buffing cylinders revolve at about 1000 rpm and the machines have to be connected to efficient dust extraction systems. The type of retannage affects the buffing properties, in that there has to be surface filling of the grain to allow the degree of buffing. Vegetable or replacement syntans are preferred.
4. DUST REMOVAL - with the collection of the dust for disposal
After each buffing operation, the leather passes on the conveyor of an air-blast de-dusting machine underneath a thin jet of compressed air, which clears the dust by blowing it into the attached extraction system. It is important that the surface is absolutely clean, and free of dust, for proper finishing and appearance.
5. IMPREGNATE
This operation is an option and has the object to reduce the looseness of the leather structure by making it tighter and firmer, and to improve the selection. It is used on leather, which will not be suitable as full grain, and has been buffed. This buffing needs to be done so that the whole surface has an even absorption. If leather is given a relatively heavy finish coat, the appearance is often unsatisfactory because it does not look natural and has a poor break. To avoid this, corrected grain leathers are sometimes impregnated with penetrating dispersions. These must penetrate deeply and stick the looser layers of the structure together. About 20-30 grams of mixture are applied per square foot, which has to be done by curtain coater, roller machine or airless spray. After standing overnight to allow maximum penetration, the leather is dried flat, preferably on a lower temperature vacuum machine. The surface is then either polished, if it is full grain, or rebuffed, if corrected, with a fine 400-grit paper and de-dusted. The result is a smooth sealed surface ready for further finishing.
6. DYE STAIN
Spray staining with liquid dye solutions is done to colour the surface of un-dyed leather and to level drum dyed shades. It is used for all grades of leather.
7. POLISH
This is done with a fast revolving cylinder made of stone, felt or resin roller and used on all types
of hides and skins. It flattens the grain and softens the leather, with applications before, and between finishing coats.
8. BASE COAT
This is the first and the most important coat of finish because it has to provide the adhesion of the whole film to the actual leather. The composition is formulated to meet this priority. The polymers used are soft and flexible. The formulation will usually include some covering pigments and fillers, to hide as many defects as possible.
9. PIGMENT COAT
This is considered to be a main covering coat due to its pigment proportion at 100-150 grams per litre. It can be applied by pad, roller or spray. Later coats have reduced pigment levels to improve the natural appearance. Organic pigments are more natural than inorganic and can be used at 25 grams per litre, without affecting the transparent look. It should always look as natural as possible.
10. CONTRAST COAT
This transparent coloured coat contains dyestuffs, which is slightly darker than, and contrasts with the colour of, the covering base coat. The effect of this colour contrast is to appear as an aniline finish, with the clear dyed film disguising the pigmented look below it.
11. TOP COAT
The final coat has to protect the coloured film below and is important for the fastness properties of the film. It determines the final look and handle of the finish. Traditionally, it may be in solvent or low- solvent solution. Special cross-linking systems to cross-link acrylics and urethane films are now used to achieve the same properties without solvent emission being a problem.
12. PRESS
Pressing and ironing are intermediate and final operations in building up the finish film. The straight through heated rollers are preferable for productivity and maintaining leather softness. The hydraulic ram presses use heavier pressure to compress the fibre structure, and are essential for obtaining an effective embossing print.
13. GLAZE
Classic glazed kid is made by the original design machine with a glazing jack, usually of glass, which rubs the leather surface with a reciprocating action. The heat and pressure produced give a deep glaze effect, due to the protein binders and dyes, and gives a true aniline appearance. The machine principle is unchanged for many years and needs skilled operators. Although, there are safety concerns in the handling of the leathers, it does produce a unique appearance. The wet fastness is a problem. A rotary ironing machine gives the nearest alternative effect, and does not need the same amount of skill for operation. It is also used for hides.
14. DRY DRUM (MILL) AND TOGGLE - some dust produced from drum
This option of a fast revolving (20 rpm) dry drum is increasingly used to produce very soft leather with a relaxed surface appearance. It could be for upholstery, garments, or casual shoes. There are degrees of development, with dust extraction needed to clean any fibres from the atmosphere, and a moisturising spray injection. It can be done on crust leather without finish, split, suede or on finished leather, provided the finish film will withstand the mechanical action. Several hours running of the drum is often needed. The leather has to be toggled afterwards to restore the flat surface and the area.
15. FINAL SORT , and often trimming with production of dried waste finished leather pieces and
trimming
Here is the final quality check and assessment of the leather value, sorting into different grades. There is a limited amount of light trimming, where this improves the selection and allows an upgrade. This is another skilled operation and determines the financial balance of each production lot and the impression it makes on the customer. Any leather, which does not meet the standard required, has to be dealt with separately; in a different grade, reworked or rejected.
16. MEASURE
The area of the sorted leathers is measured, usually electronically on a horizontal conveyor. The accuracy of the machine needs to be checked on a daily basis with a template. The individual area of each piece can be stamped on it, together with a suitable code to identify the production lot and permit it to be traced.
17. PACK
It is important to maintain the finished appearance in packing so that the leather can arrive in the customer’s warehouse looking as attractive as it did when it was sorted in the tannery. It can be difficult to achieve this when there is a lot of handling in shipment. This normally means that some finished leather, sensitive to damage, is rolled with the grain surface on outside of the roll; others are placed grain to grain. Smaller skins are folded. The outermost piece is covered with a protective wrapper, which is then fixed tightly with a non-damaging tape or chord. It is important that the leathers are held tight to prevent any possible movement in travel. If feasible, small leathers are packed flat onto small pallets. It is important that any packing for individual rolls is permeable to avoid moisture being trapped during the time of shipment. Cartons provide the best protection against the handling in transit, with several rolls or bundles in each carton. A container shipment with cartons of leather packed by the tannery is ideal. It is essential that there should be no risk of damage from the weather. Wet, cold and heat all affect finishes and leathers.
18. DESPATCH FOR SHIPMENT
The documents for shipment need to show all information to conform to the original order and the production schedule of the tannery, to allow tracing and form the basis of future orders. These details also allow the tannery to check the financial contribution made by this production lot.
Contributed By Mr. Woodley, Michael International Consultant May, 2007
http://www.ab-corporategifts.com
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