Indian interest in Silvateam solutions
26/04/2011
The company took part in discussions about cleaner technology in Chennai at the start of this year during the India International Leather Fair.
Silvateam participated with two presentations, ‘Application of recycling vegetable tanning’ conducted by Eric Poles, leather business unit manager, and ‘Application of metal free tanning process’ by Massimo Scabbia, chief technologist.
Mr Poles explained the company’s semi-rapid vegetable tanning system. Starting from pickled or pre-tanned pelts, he explained that it is possible to carry out vegetable tanning with float in a relatively short time and with minimal damage to the grain from mechanical action. He also said the residual liquor from the tanning can be recycled indefinitely. After a few batches of leather tanned with this liquor, equilibrium is established in the concentration of tannins and non tannins. Spent liquors exhausted from colouring and precolouring have a minimum level of tannins, are very rich in salts and non tannins and can be used in the pickle instead of brine.
Massimo Scabbia explained chrome-free tanning methods that use two hybrid syntans developed by Silvateam. The hybrid syntans are based on a condensation product of 4.4 dihydroxidiphenylsulphone and a special polyaldehyde, called Ledosol XT, and a condensation product between phenol urea formaldehyde syntan and neutralised condensed naphthalene sulphonic acid, called Blancotan MSR.
This hybrid syntan requires no salt for pickling. The leathers produced are wet white with good shaving and light fastness properties and a shrinkage temperature varying from 70 to 74 degrees Celsius.
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