The leather surface may become tacky as a result of film formation by heat treatment, especially when using soft polymers. This causes sticking of the leathers to the ironing embossing plates and tackiness during piling on trestles. Apart from the additional work required to remove the leathers from the plate or cylinders or to pull the leathers apart, the finishes may also be damaged. Further more there is a risk of soiling by adhesion of dust and fiber particle (buffing or shaving dust)
Tackiness can be reduced or eliminated by adding antisticking agents. The products used for this purpose are wax or paraffin
Emulsions, non thermoplastic binders, polyurethane dispersions or the addition of emulsion lacquers. Silicone oils also have a high antisticking effect. However, their use is not recommended as adhesion of the subsequent finishes may be impaired.
Defoamers
Strong foaming may develop especially during curtain coating because of the constant recirculation of the finishing floats. As a consequence many air bubbles are trapped in the finish film and make en even film formulation impossible. Furthermore, smooth running of the curtain is disturbed which may result in complete tearing of the curtain. Foaming can be prevented by adding alcohol, ethyle glycol, and isopropyl alcohol emulsion lacquers or by using stable binding agents. If foaming does not disappear it is recommended that the circulation rate of the feed pump be reduced.
fMM&T looking to expand in 2010
India
Published: 14 April, 2010
The event, which is organised by APLF Ltd, aims to bring together buyers and sellers of footwear, leather, components and leathergoods to both a domestic and international audience.
Last year the first event attracted 140 exhibitors and some 3,250 buyers and so far the organsiers have booked 130 exhibitors and aim to have a total of 180 by the time the show takes place. Exhibitors for the 2010 represent some 44 different countries making the event international.
It is widely acknowledged in the industry that India has the size and capacity for two major trade shows annually, one serving the south centred around Chennai and one in the north. With the highly successful IILF taking place each January in Chennai fMM&T has the opportunity to serve other parts of the Indian sector clustered around Agra, Kanpur, Ambala, New Delhi and Jallandhar. The organisers also bring considerable experience in operating international trade shows in the leather industry such as the APLF and ACLE.
fMM&T is backed by a number of Indian national and regional associations representing the footwear, leather and components sectors including event partners, the Indian Footwear Components Manufacturers Association (IFCOMA).
The total leather and leather products industry in India is estimated to turnover $7 billion per annum and despite a slow down during the recent global economic crisis has grown steadily over the past decade.
REACh – no major impact for tanners
Worldwide
Published: 13 April, 2010
The impact of the REACh regulations that came into force across the European Union on June 1, 2007 in most cases will not have a major effect on chemical costs that will be passed on to tanners, nor on the availability of chemicals. During a Unido sponsored meeting held in Addis Ababa, Ethiopia on January 18, Jakov Buljan, Unido consultant, outlined the impact of the regulations known fully as Registration, Evaluation, Authorisation and Restriction of Chemicals. He said that at the beginning of 2010 a further 15 chemicals had been added to the banned list and he gave an overview of how the regulations work.
Leather itself is classed as product and is not covered under the regulations although the leather chemicals used in the leather and leather product sectors do. Buljan also confirmed that the regulations only apply to the EU however, virtually every country would be affected by REACh if their products were subsequently sold in European markets.
During the discussion following the presentation, Elton Hurlow, marketing manager of chemical producer Buckman said that the cost and administration burden of the regulation was being borne largely by the chemical companies, but that tanners should obtain letters from their chemical suppliers showing that the chemicals they were buying were compliant with REACh regulations. He estimated that between $50,000 to $150,000 in extra work and compliance will be added to the cost of each low risk product that would be absorbed into chemical maker’s general overheads. He also confirmed that chemical companies were working together to avoid duplication of work on many products and across industrial sectors and that this will keep costs down.
It was mentioned that there may be a few chemicals used in the tanning industry that might be regarded as high risk and could have significant compliance costs as additional data would be required from an independent source. This could run into the millions of dollars in the worse cases.
Biocides used in the leather industry, such as fungicides and bactericides, are an example of substances requiring additional testing and data, but they are already covered outside of REACh through the Biocidal Product Directive legislation.
Tanners with any major concerns about the regulations should consult their chemical suppliers or a professional organisation that has knowledge of the regulations.
Fixing agents
Finishes on the basis of albumin binders have no adequate water-resistance and therefore require additional fixation. Formaldehyde is still most commonly used product. It is mostly applied as a 5-10 % solution and sprayed onto the slightly dried casein binder coat. With polyamide-modified casein binders the formaldehyde solution may also be added directly to the ground or top coating float acid and/or chromium (iii) salts improve the fixing effect, however they are not compatible with the modified casein binders.
In view of ecological requirements and the often unpleasant odour of formaldehyde, modified melamine compounds are also in us. For effective fixation they require a minimum temperature of 175 ⁰C. Glutaraldehyde can also be used; however it is not suitable for white and pale leathers as it results in yellowing.
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