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New composite material produced by means of reaction of technopolymers and leather

Polymers are already applied in the tanning industry to
improve aesthetic characteristics. By utilizing different
polymers (technopolymers) we intend to obtain new composite
leather products with higher mechanical performances.

The aim of this project is to set up an industrial process for the production of composite materials using hides and Engineering Polymers with strong mechanical properties. The final composite materials will be characterised by the typical properties of both the leather (softness and other suitable characteristics for the fashion circuit) and the Engineering Polymers (strong mechanical properties, etc.), but they will not be either, presenting their own specific identity. For this reason, a new hide impregnation methodology will be developed, increasing the polymers' ability to firmly penetrate the structure through the establishment of true chemical bonds, so hides with properties unobtainable with present technologies will be produced. In order to achieve such a result, the impregnation methodology should first be examined with several polymers having both good mechanical properties and functional groups capable of assuring good bonding ability with the hide structure. The treatment of the already tanned hide with pre-formed polymers seems to be the simplest method from the points of view of feasibility and process economy. In any case, the macromolecules' capacity of penetrating the structure and their homogeneous distribution should be verified. This will be monitored through spectroscopic analyses and selective extraction. On the basis of the results obtained, and in order to compare the performances, the possibility to impregnate the hides with Engineering Polymers during the final step of tanning phase will also be evaluated, with the aim of obtaining more expanded hides and improving the polymers' penetration into the hides. The utilisation of polymers belonging to the so-called class of Engineering Polymers is due to their strong mechanical properties, strong enough to substitute metals in many applications. Generally the constitutive macromolecules of Engineering Polymers are linear and obtained by polycondensation of relatively stiff monomeric units. This leads to an increase in the vitreous transition temperature (Tg) well above the ambient and fusion temperature (Tm) above 200 deg.C and high elastic modules. (In fact high values of Tg and Tm are also synonymous with high bio-chemical and mechanical stability of the tanned hide over long periods). The preparation for polycondensation also implies the presence, along the macromolecular chain, of functional groups -O-, -CO-, -NH-, etc., that allow good interactions with other materials, in particular the functional groups present in the collagen side chains. Moreover, limited amounts (10-20% wgt) of such Engineering Polymers can cause significant increases in the technical-mechanical properties of the hides, if well distributed in the bulk of the compound. The aliphatic polyamides (Tg=60 deg.C, Tm=225-245 deg.C and elastic module 20,000-25,000 Kg/sq.cm) are low-cost materials with the possibility of significantly improving the mechanical properties of hides, that become more resistant to traction, abrasion and stripping. Similar results can also be obtained with vinyl polymers with hydrocarbonic chain and side functional chains like the copolymers styrene-acrylonitrile (SAN, Tg=115 deg.C and the elastic module of about 35,000 Kg/sq.cm). The research will include laboratory activities and pilot experimentation with the aim of optimising the process and characterising the obtained composite product from the physico-chemical (Tg, Tm, impermeability, resistance to vapour, traction, abrasion, elasticity module, flexibility, softness, etc.) and biological (stability to bacterial and fungi attacks and UV resistance) points of view, in order to satisfy the Standard Methods and the current Safety and quality Standards. Companies in the tanning sector, ENEA (the Pisa office), the Department of Industrial Chemistry of PISA UNIVERSITY and specific consultants for the various research sectors will participate in the project. The work is planned to last 24 months. Keywords: leather, polymers, tanning.
Acronym: 
TECHNO-LEATHER
Project ID: 
2 140
Start date: 
01-12-1999
Project Duration: 
24months
Project costs: 
2 800 000.00€
Technological Area: 
Market Area: 

Raising the productivity and competitiveness of European businesses through technology. Boosting national economies on the international market, and strengthening the basis for sustainable prosperity and employment.