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TECHNICAL LIBRARY

Featuring more than 1,000 searchable technical papers, business features, country commentaries and fashion articles from editions of World Leather going back to 2002. The papers are categorised into nine topics to make the library easy to navigate.


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WET END: Soaking, liming/unharing, deliming & bating; Pickling & tanning

62 Items Found

 
Sustainable sourcing of tannins
In this article, Italian chemicals manufacturer Silvateam offers more details about how it sources sustainable tannins, and its use of quebracho from Argentina and of tara from Peru. In the previous issue of World Leather, it focussed on its sourcing of chestnut tannins from Italy.
World Leather - Jun/July 2019
Hides go to waste
Demand for high-quality leather remains strong, but no one in the global industry can be in any doubt that lower-value material is harder to sell than at any time in living memory. As a result, what we thought would never happen has come to pass: hides really are going to waste.
World Leather - Apr/May 2019
Taking tanning to the next level with an improved pickle product
Although chrome tanning is already at what leather chemicals manufacturer Lanxess calls “a high level of performance”, it explains that it is working to make further improvements to this tanning method.
World Leather - Apr/May 2019
Tannins: a sustainable solution
In the first of two articles, Italian chemicals manufacturer Silvateam offers insight into sources of sustainable tannins from areas of Italy and South America. The second article will contain information about its use of quebracho from Argentina and tara from Peru. This paper focuses on its efforts to source chestnut tannins from Italy in a manner that respects the environment while also supporting the economic growth of local rural areas.
World Leather - Apr/May 2019
Mercier Turner augments its Newsplit machine
Since World Leather last published information about the Newsplit splitting machine from French tanning machinery provider Mercier Turner in 2015, the company has continued to make progress on a seven-year project to refine and improve lime-splitting capabilities.
World Leather - Feb/Mar 2019
LIFE Biopol project moves out of the laboratory
During the 2019 India International Leather Fair (IILF) in Chennai, World Leather sat down with commercial director wet end for Smit & zoon, Arnaud Backbier, to discuss the LIFE Biopol project that the company has been involved with through Codyeco, the Italian leather chemicals producer it acquired in 2017.
World Leather - Feb/Mar 2019
Elimination of wastewaters from liming/unhairing and chrome tanning in wet blue manufacture
This paper concerns a radical new approach to the unhairing/liming and chrome tanning processes for wet salted bovine hides. The technology - developed by BIOSK Chemicals, China - was presented at the 11th Asian International Conference of Leather Science and Technology (2018), Xi’an. These techniques, as used by four major tanneries in China, are described in detail where major savings in chemicals and water are being made. In addition, major environmental issues arising from traditional methods of leather making are being avoided.
World Leather - Dec/Jan 2018
Soaking of bovine hides and its control in the tannery
Tanners can pay a heavy price for paying too little attention to soaking bovine hides. Mistakes at this stage produce faults that cannot be corrected later.
World Leather - Dec/Jan 2018
Generating consistent leather splits for footwear
Tanning technology provider Gemata has said the Starsplit splitting machine it developed and introduced to the market in 2017 can bring about a revolution in the lime-splitting process. This could be very good news for tanners but equally so for the large number of footwear brands interested in using leather splits in the shoes they are preparing for the coming seasons.
World Leather - Oct/Nov 2018
Salt and acid-less tanning system from Buckman
Buckman has developed technology that it claims can eliminate the pickling and basification stages in chrome-tanning.
World Leather - Apr/May 2018
Boron in hide and skin curing processes
With the prevalence of tannery effluent being used for irrigation, tanners need to be aware of the specific monitoring requirements pertaining to soil and water sources as this article about boron illustrates.
World Leather - Dec/Jan 2017
Closed-loop liming and chromium tanning systems in industrial practice
Chinese leather chemicals manufacturer Biosk continues to roll out its system for offering tanners closed-loop liming and chrome-tanning procedures, in which floats can be reused time and time again.
World Leather - Dec/Jan 2017
Gemata introduces revolutionary splitting machine
We take a closer look at Gemata’s Starsplit splitting machine, which has features that include a newly developed automatic feeder system.
World Leather - Oct/Nov 2017
Formaldehyde and acetaldehyde on leather: similarities and discrepancies
BASF presents new emission data that could help to minimise formaldehyde in leathers.
World Leather - Aug/Sept 2017
The difference between an interesting invention and a disruptive innovation
Lanxess’s Dietrich Tegtmeyer examines what makes a true innovation with reference to a fully automated plant for converting shavings into retanning chemicals being tested at Heller-Leder tannery in Germany.
World Leather - Aug/Sept 2017
Stahl’s Centre of Excellence focuses on apparel and furniture
World Leather reports on the opening of Stahl’s new Centre of Excellence dedicated to apparel and furniture in northeastern Spain.
World Leather - June/July 2017
Polycarbodiimides as classificationfree and easy to use crosslinkers for water-based coatings
A new family of VOC-free polycarbodiimides in aqueous delivery form is providing an alternative way of delivering crosslinkers for water-based coatings.
World Leather - Apr/May 2017
Developments in fatliquoring
At February’s IULTCS Congress in Chennai, Dirick von Behr, technical manager for leather at chemicals manufacturer Smit & zoon, presented a paper entitled “Method for determining the optimised exhaustion of fatliquors to minimise the ETP-inflow”. The paper referenced the upcoming changes in German regulations for the treatment of tannery wastewater. World Leather sat down with Mr von Behr to find out more.
World Leather - Apr/May 2017
Tackling “veininess”, Part two
The second and final part of a paper from Lanxess examining the best strategy for addressing the problem of veininess in hides. The first part appeared in World Leather December 2016-January 2017.
World Leather - Feb/Mar 2017
greenLIFE 2: A novel Key Performance Indicator for the assessment of the liming process
Green Leather Industry for the Environment (greenLIFE) is a project run by a group of industry partners in Italy’s Arzignano tanning cluster. The project partners have committed to sharing their findings by publishing a series of papers in World Leather. This is the second of six greenLIFE articles.
World Leather - Feb/Mar 2017
greenLIFE 1: Oxidative liming
In 2014, two of the biggest tanners in the Arzignano cluster, Gruppo Dani and Gruppo Mastrotto, formally launched a joint project called Green Leather Industry for the Environment (greenLIFE), on which they have worked with three technical partners: chemical supplier Ikem, biotechnology firm Ilsa and the cluster’s wastewater treatment service provider, Acque del Chiampo. It has the aim of promoting sustainability in the tanning industry. Half of the funding for greenLIFE came from the European Union, which has asked the project partners to share their findings with the wider leather industry. The partners have picked World Leather as the ideal platform on which to publish the results of greenLIFE. This paper, the first of six World Leather will publish in the course of 2017, kicks the series off.
World Leather - Dec/Jan 2016
Improving the biodegradability of vegetable tanned leather
Tanning stabilises protein, thus making leathers more difficult to biodegrade than raw hides and skins, composting offers a solution to waste disposal problems associated with these leather products. In this event this offers a strong alternative to land-fill disposal or incineration of waste.
World Leather - Dec/Jan 2016
ReVeal – the Dutch veal and calfskin industry opens its doors
Leather chemicals manufacturer Stahl hosted a one-day event called ReVeal last November. The aim was to give finished product brands up-to-date information about transparency and traceability in the leather supply chain, with the focus firmly on Dutch calf leather.
World Leather - Dec/Jan 2016
Chamois leather process based on rubber seed oil, and rationalisation of the oxidation stage
Chamois leather has unique uses, including high quality gasoline filtration, gloves, garments, and cleaning and drying of optical equipment, spectacles, windows, vehicle, jewellery, and silverware. Indonesia is a rubber producing country with the largest rubber plantations in the world. Here, it produces rubber seeds from about 1,500 kg/hectare of land, and this resource has not been utilised optimally. It was considered that rubber seed oil could be used for chamois leather tanning, and an investigation took place to see if: [1] rubber seed oil could be used as chamois leather tanning agent [2] the time consuming oxidation stage could be rationalised.
World Leather - Oct/Nov 2016
A radical new approach within liming and chrome tanning technologies
A revolutionary approach to liming and tanning practices has been successfully developed by BIOSK (SQ) Chemicals, China. Concentrated floats from liming and tanning are retained in self-contained cycles and reused in processing.
World Leather - Aug/Sept 2016
Studies on the determination of soilingand cleaning behaviour of leather. Part 2: Inter-laboratory tests with specificreference concerning the cleaning step
In Part 1 of this study, published in World Leather February/March 2016, inter-laboratory tests enabled a closer view on the test procedures on soiling and cleaning behaviour of leather and their impact on the final result.
World Leather - June/July 2016
The influence of syntans on the assembly of collagen
Since the introduction of the first syntan one hundred years ago by BASF, the role of syntans in the tanning process has changed significantly. While syntans were initially used as dispersers and accelerators for vegetable tannins, they were applied as sole tanning agents later, and with the wide acceptance of chromium or glutaraldehyde tanning, they are now mainly used in the re-tanning process.
World Leather - Apr/May 2016
Studies on the determination of soiling and cleaning behaviour of leather. Part 1: Inter-laboratory test on soiling and cleaning behaviour of leather
A main task of the VGCT Commission “Leather Testing and Assessment” is the detailed examination for the determination of physical and colour fastness properties of leather, especially in terms of procedures. The intention is to detect performance characteristics of the procedures and to reveal and eliminate possible sources of error. Due to the trend for light-coloured leather for upholstery in the automotive and furniture sector, the soiling and cleaning behaviour of leather and its determination gain in importance. From the multiplicity of available test procedures for the characterisation of soiling and cleaning behaviour, the procedure VDA 230-212 was chosen and considered closely by means of an inter-laboratory test programme. In the context each procedural step was examined closely with regard to their impact on the final result of the test. Part 1 presents the results of the inter-laboratory test on soiling and cleaning behaviour of leather. Part 2 (to be published in World Leather later in 2016) will deal with the validation of an optimised mechanical cleaning step.
World Leather - Apr/May 2016
Glutaraldehyde: Proven technology for white metal-free leathers Part 2 of 2: The versatility of glutaraldehyde in leather making
Part 1 of this paper, published in December/January 20015/16 and entitled Pre-tanning with modified glutaraldehyde, describes the theory and practice of glutaraldehyde tanning, ecological and toxicological aspects, and pre-tanning including a guideline formulation. In this paper, Part 2, the study expands upon the versatility of this product, and includes two guideline processes for the retannage and fatliquoring of automotive and footwear leathers.
World Leather - Feb/Mar 2016
Glutaraldehyde: Proven technology for white metal-free leathers Part 1of 2: Pre-tanning with modified glutaraldehyde
The theory and practice of glutaraldehyde tanning Glutaraldehyde first received attention as a tanning agent in the 1960s. For monoaldehydes, the higher homologous species a reprogressively less effective tanning agents than formaldehyde. In general, the same applies to dialdehydes in relation to the smallest example glyoxal. However, glutaraldehyde is an exception to this rule as it is a very efficient tanning agent.
World Leather - Dec/Jan 2015
SLTC 117th Annual Conference / The Mary Rose
The 118th Annual Conference of the SLTC was held at The University of Northampton 25th April 2015. The event was attended by 79 delegates, and was followed in the evening by the SLTC Annual Dinner Dance.
World Leather - June/July 2015
Perceptions of chrome and chrome-free tanning systems by Silvateam, Italy
The findings are based on the opinions of a considerable range of tanneries producing chrome tanned, chrome tanned and chrome-free, and vegetable tanned leathers.
World Leather - Apr/May 2015
Sustainable tanning: waste minimisation in the tannery
Over the last few years the chemical industry has introduced many new technical solutions to the leather industry. Most offer environmental advantage or reduced risk of harm, and these advances are set to continue. In particular, novel enzymatic beamhouse systems and new wet white technologies are two major wet-end process steps where developments have been focused. Advances in these areas will lead to more sustainable leather articles and process conditions with a lower environmental impact.
World Leather - Apr/May 2014
Hybrid chrome tannage coupled with recycling for minimisation of residual chrome from tanning
Today, 80-90% of leathers in the world are tanned with chrome. The increasing requirements of producing safe leathers in a sustainable way have led Silvateam to develop a new technology that permits: • Increase the fixation of chrome oxide to the leather fibres; • Minimise the use of chrome salts in the tanning processes; • Reduce the chrome content in wastewaters.
World Leather - Feb/Mar 2014
Flame resistant leathers for the aviation industry
Clariant: There is a demand for flame retardancy, and a new approach based on EasyWhite Tan achieves these critical specifications as well as meeting the need for secure and environmentally friendlier ingredients and processes.
World Leather - Dec/Jan 2013
Somalia: The Berbera Tannery
The region that today encompasses Somaliland was home to the earliest civilization in the region. The most salient feature of this ancient civilization is thought to be the Laas Geel Neolithic cave paintings, which are among the oldest such rock art in Africa. These cave paintings are located in a site outside Hargeisa, the capital of the Somaliland region, and were untouched and intact for nearly 5-10,000 years until their recent rediscovery at the end of 2002.
World Leather - Dec/Jan 2013
Oxidative unhairing
The following overview by R.P.Daniels is based on: • Presentations: G.A.Defeo, Ars Tinctoria SRL (Italy), and S.Dani, Italprogetti Engineering (Italy): LGR, Reutlingen 2011 and Freiberg Leather Days April 2012. • G. Defeo, ARL Tinctoria,: SLTC Conference Northampton 2013. • Information from: Gruppo Dani, Arzignano, Italy 2012 and Italprogetti, Italy 2013.
World Leather - Oct/Nov 2013
X-Zyme – a novel beamhouse technology
In a partnership for the tanning industry, Novozymes and Lanxess are combining patented biotechnology with chemical and global processing know-how. The two companies are introducing a novel beamhouse process that delivers high-quality pelts and significantly improved effluents.
World Leather - Aug/Sep 2013
Tannery machinery accessories and spare parts from Italy
Providing the many leather producers clustered in the leather centres of Italy with a just-in-time specialist service, spares and an array of auxiliary devices has created a huge marketing opportunity for the small but technically qualified enterprise.
World Leather - Feb/Mar 2013
How a new approach to the tannery drum developed
A historical look at the evolution of the drum and of Swiss tannery Huni.
World Leather - Feb/Mar 2013
Machines in the Tannery: Innovators & Research - Turner
The core business of the company is the production of classic tannery machinery, including fleshing, setting and shaving machines.
World Leather - Feb/Mar 2012
Innovation Part 1: Recycling and regeneration
Twenty world standard tanneries have opened their doors for in-depth study as part of Tannery of the Year Awards 2009 and 2011. Considerable technical information has been published in World Leather following these visits, and there has been an emphasis on environmental aspects. This article is the first in a series that picks out some of the highlights from the innovation stories these top tanneries have shared with us.
World Leather - Oct/Nov 2011
Deep shelf/slow speed processing vessels
Drums fitted with deep shelves and rotating at relatively slow speeds for wet processing hides into leather were first brought into use in the mid-1990s. Since that time the technology has evolved, and they are now being used for soaking, liming, tanning and retanning/dyeing.
World Leather - Dec/Jan 2010
Small moulds can cause big problems
Asignificant cause of loss in value in leather processing is due to fungal or bacterial growth, and even biocidal agents fail in certain cases. These small microorganisms are not visible to the naked eye, and are normally only identified when the defect reaches a certain level.
World Leather - Aug/Sep 2010
The mechanisms of effective soaking: Fresh and brine-cured hides
The soaking of fresh cattle hides differs from the soaking of salted or brine-cured cattle hides. This paper reveals the differences between these two types of raw material, including the relationship between hyaluronic acid extraction from the hide into the float and effective soaking, and other related issues.
World Leather - Feb/Mar 2010
Carbon dioxide deliming of full thickness hides
In World Leather May 2007, a list was given of 45 papers that had been published which addressed various aspects of salinity that arise from leather manufacture. To make the compendium as complete as possible, some papers that were still awaiting publication were also included. This was an unusual step but, with consideration to the growing environmental pressures that tanners are facing, and to make the compendium comprehensive, it was considered right to include this material. The following is one of the papers that was awaiting publication, and concerns the use of carbon dioxide as a proven method of reducing the total dissolved solids (TDS) content of wastewaters. CSIRO was at the forefront in the investigation of this technology and its introduction into commercial use. When reading this paper, it should be remembered that the original report was produced in the early 1990s and, as it has only been subject to a very light edit, some minor details will have now changed. The information set down is, however, fundamental to the highly successful technology and this is probably the most informative study written on this subject.
World Leather - 01 - Feb/Mar 2008
The soaking, unhairing and liming process – Part 3 of 3: Managing the process formulation
In Parts 1 and 2 of this three-part series, detailed guidelines for the successful soaking and unhairing/liming of bovine hides were presented, but there is a problem in practical manufacture. Not only are these initial steps in leather-making the foundation of good quality leather, but the appearance of hides and skins after unhairing and liming is difficult to relate with the final leather.
World Leather - 05 - Aug/Sept 2007
The practicalities of the unhairing/liming process. Part 2 of 3
This second paper provides detailed information on the key aspects that underpin good practice within commercial unhairing/liming systems.
World Leather - 02 - April 2007
The soaking, unhairing and liming process: Part 1 of 3
The practicalities of the soaking process.
World Leather - Nov 2006
Technologies to improve the useful area of leather
The manufacturing of leather is facing diverse challenges including pressure from the eco-toxicity point of view, in the form of stringent new regulations. The measures necessary to deal with these issues add to the cost pressure that tanners are experiencing.
World Leather - Aug/Sep 2006
Back to Basics: Modifying the skin structure & Hides and skins and mechanical forces
Essay 1: Before first-time drying and the formation of a flat stable substrate, the conversion of hides and skins into leather can be viewed as two distinct stages: the removal of unwanted skin components and the location of specific materials within the collagen structure. Essay 2: The role of the process vessel in leather manufacture is greater than that of a chemical reactor. While chemical reactions take place, considerable forces are applied to the goods undergoing process. The way these forces are received, and the outcome, strongly affects the chemical distribution within each hide or skin.
World Leather - Nov 2005
Optimum chrome tanning of hides and modified Thrublu process for lime-split hides
Chrome tanning for a long time enjoyed a unique position amongst tanners and almost 90% of leather produced is chrome tanned. A number of studies have been published suggesting that Chromium(III) itself may be toxic at higher levels and Chromium(VI) is a known carcinogen. So, tanners have to consider how best to modify their tanning process for better exhaustion of chrome and look for alternative means to minimise the impact of tanning on the environment.
World Leather - Nov 2005
The diffusion barrier within the unhairing process
World Leather takes a look at the hair-saving processes for bovine hides that are being applied in tanneries in several countries to replace traditional hair burning systems.
World Leather - Oct 2005
Removing phospholipids from hides: Looking back on a “New perspective on wet processing”
The paper "New perspective on wet processing" was published in World Leather October/November 1993, in which the advantages offered by the removal of phospholipids were discussed. Given that the value of raw hides and leather selling prices - strongly influenced by area and quality - are so important to the tanner, perhaps it's time to re-evaluate this technology.
World Leather - Oct 2005
Hides and skins: Temperature and physical change
This article takes a look at the profound influence temperature has on the physical properties of hides and skins within every stage of leather manufacture.
World Leather - Aug/Sep 2005
Hides and skins: Physical change and effects within chemical processing
The forces applied to skins in wet chemical processing relate to the type of processing vessel and its internal configuration. These forces can be viewed as constant when processing at uniform loadings, float levels, speed of rotation and time. We take a look how the way these forces act will vary as the skin physically changes.
World Leather - Aug/Sep 2005
A practical alternative to salt for the preservation of hides and skins
Salt as a preservative for hides and skins is simple in application, low in cost and effective. Accordingly it is the most common form of preservation, but in practical term salt cannot be removed within effluent treatment. It enters the environment where the true costs are experienced in reality.
World Leather - May 2005
The role of bound and free water in the liming process
In World Leather August/September 2004, observations were presented showing that if limed hides were washed at different temperatures, a warmer wash caused an increase in softness and hide relaxation, but without change in the total water content. References were made to earlier investigations that address aspects that need taking into account. Translations and detailed studies of these reports are summarised in the following paper.
World Leather - Dec/Jan 2004
Bating: gaining area while retaining cutting values
It is almost 100 years since Otto Röhm introduced the first industrial application of an enzymatic product. This was the bating process of animal hides within leather production, the enzymes being derived from pancreatic glands. This can be seen
World Leather - Oct 2004
Observations: Temperature related relaxation within liming and other wet processes
It is well known that by liming at higher temperatures, say, 29°C instead of 25°C, that hides and skins are softer, show less draw and growth marks, and appear less swollen. In addition, after fleshing there is a greater loss of fine wrinkles in
World Leather - Aug/Sep 2004
Wasserglass in leather production
The main objective of this project—funded by the CRAFT programme of the EC(2)—was to develop findings from a previous investigation on the application of Wasserglass. In the study, procedures for pelt treatment with Wasserglass(3)
World Leather - Aug/Sep 2004
Aqueous degreasing and the custom designed surfactant
The degreasing of hides and skins can be considered state of the art. Excluding the use of solvents, the most effective water-based products are nonylphenol ethoxylates (NPEs).
World Leather - Nov 2003

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