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New types of water-repellent leathers
Production of quality leather in Europe is largely in the hands of small and medium-sized companies that can find it difficult to launch new technologies. In the PlasmaLeather project, these small producers joined with research institutes to develop an innovative and cleaner way to make leather water repellent.
 An effective hydrophobising (water-repellent) treatment for leather extends its life and makes it more practical, but the traditional processes currently used by tanneries require the application of specific chemicals to impart water and stain resistance. The more luxurious, softer and natural leathers are liable easily to be marked or stained and cannot be treated easily by traditional processes without a concomitant losings of their organoleptic characteristics feel and aspect and thus much of their commercial value. The PlasmaLeather CRAFT project (Cold Plasma Treatment for New, High-Quality Water Repellent Leathers) aimed to adapt a cold plasma prototype process, developed for treating fabric, to a wide range of leathers. This process, they hoped, would enable give leathers to be superficially a hydrophobic surface sed without the using traditional water repellent agents and transform the sector into a knowledge-based high-tech industry. This, in turn, would extend the market for quality leathers and provide training opportunities and a better working environment for employees in the leather industry.
Tanneries join research efforts
The majority of Europe's artisan tanneries are found in Italy, Spain and Greece. Some of the foremost among them joined the project, together with related trade associations and research groups. The academic partner was the Universitá degli Studi of Milan-Bicocca, Physics Department. “This mix was ideal for the project,” says Dr Alessandra Siena of Conciaricerca Italia – the research company promoted by UNIC (The Italian Tanners' Association), which managed the project for the coordinator Sicerp SpA. “The SMEs could help with the initial phase of data collection on the characteristics of current leathers and the hydrophobising processes available. They were familiar with the properties that customers would expect in the treated leather and could specify requirements.”
The research partners then went on to develop a prototype cold plasma hydrophobisation unit. Cold plasmas, partially ionised gases and vapours produced in a low-temperature vacuum, have many scientific and technical uses, including surface treatments to impart specific properties such as water repellence. The objective was to optimise a pilot-scale system that was innovative, versatile and virtually chemical-free. The SMEs prepared leathers to the specifications needed by the process and then assessed the quality of the treated samples produced.
System proven
At the end of the two-year project in 2004, the partners had thoroughly investigated the process characteristics and defined the optimal parameters. They successfully developed a semi-industrial scale prototype that uses a cold plasma process to produce new types of improved-quality water repellent leather. “It can treat leathers of a size up to 80 x 50 cm,” explains Siena “and is therefore suitable for lamb, kid, goat, sheepskin and pigskin as well as baby calf and most exotic skins. The product is an innovative leather that is water resistant but with no traditional water-repellent agents on its surface. The process does not affect its natural appearance and aesthetic properties. For example soft leathers such aniline, nubuck and velour types resist spotting and staining while retaining their attractive feel, which is not possible with the traditional processes.”
A certain amount of development work remains to be done before the system can be used for commercial production. “To make the operation profitable, the productivity rate will have to be increased and the operating costs reduced,” comments Siena. “This will require a further phase of industrialisation and commercial upgrading of the technology.” The machine needs to be integrated into a production line with faster loading and unloading and more flexible operation. This should enable the production of high-value products that meet the market requirements of Europe's leather industry.
Advantages all round
This has been a significant CRAFT project in giving the small leather companies an international dimension and an involvement in research programmes for the first time. Participating SMEs are enthusiastic and affirm that PlasmaLeather is relevant to their core business. The sector is not financially strong and stands to benefit from better product quality. The project could serve as a model for other traditional craft industries whose SMEs do not do research or make international contacts. The new process will raise the technological level of the sector and provide work and training opportunities. The technology can be transferred to other countries with even smaller firms that could not join in such a programme. “Besides generating innovative articles,” concludes Siena, “the PlasmaLeather process reduces air emissions, is water-free and virtually chemical-free and will improve working conditions in the sector.” |
