Retanning Resin rev.12 from 31/03/13

Aspect Liquid
Colour Yellowish ochre
Odour Characteristic
pH (sol. 10%) 6.0 ± 0.5
Active Matter 36 % ± 1.0
Solubility Soluble
Ionic ChargeAnionic

Alfasin W is a molecule made of a large polymeric chain containing stably-linked phenolic groups.

It has a high tanning capacity due to the presence of phenolic groups and a high filling power due to the ability of his chains to establish cross-links.
The innovation lies in its ability to deploy long chains that link the fibers together during the fixation phase inside the skin.
Molecules connect via the net linking established by the chain itself. Meanwhile a second level of fixing is secured by the phenolic moieties reacting with the moieties of the skin.
During the cross-linking phase, phenolic moieties that are too distant to react with the protein fibers remain free to establish links with other chemicals used in the retanning step of the process (i.e. fatliquors, dyestuff, synthetic tannins and vegetable extracts). As a consequence, retanning baths are more exhausted and the skins appear fuller, softer and with more saturated colours than with conventional retanning. Importantly, before the reticulation phase, Alfasine W accumulates within the empty space between the fibers, giving Alfasine W its characteristically high penetration. We have observed that the global distribution of the polymer in the skin was not uniform and was higher in the areas with more space between the fibers. In turn, this results in a large filling effect in the most spongy parts of the leather, without making areas that are naturally more compact harder. The product is stable with all anionic compounds.
The product comes as a yellowish liquid and is designed for manufacturing White leather.
The polymer has an excellent penetration capacity at a pH higher than 5.0 and a temperature lower than 35°C.
The product starts to react when the pH falls under the value of 3.8, below which it fixes completely.
A high temperature favours the cross-linking between the different molecules present in the fibers. The stability to light is excellent.


Alfasine W shows high qualities in chrome leather retanning as well as vegetable leather processing.
This versatile compound is particularly effective in the production of pastel coloured and white leathers. Items such as leathergoods, upholstery, furniture and garments produced from full grain or split are notably enhanced by Alfasine W.
Alfasine W’s main advantages are:
- Greater fullness of the skin.
- Firm grain and reduction of looseness.
- Excellent exhaustion of the retanning bath.


Chemical-physical properties of the product have been determined in accordance with internal procedures by methods of analysis provided by national and / or internationally recognized standards. The information contained in this data sheet is based on our current knowledge. Given the multiplicity of factors that can influence the processing and use of our products, it is the responsibility of the customer to carry out its part tests and controls.
We cannot endorse any responsibility consequent to an incorrect use of the product.