SYNTANS Syntans: abbreviation for synthetic tannins. It covers substances which are manufactured to replace partially or completely, the natural vegetable extracts, to accelerate production and to make it cheaper. Introduction of new functional groups which do not occur in vegetable tannins such as sulfonic groups opened new prospects for tanning. Syntans are frequently used in retanning chrome leather. There are replacement syntans and auxiliary (assisting to the tanning process) syntans. Sizes of 800 or less, which correspond to 2-4 aromatic rings are of practical importance. Molecules of greater sizes do not tan or tan only superficially. Bonds between aromatic rings in syntans are essential for their properties. For example extension of a molecule by a CH2 member weakens tanning ability of syntan. Replacement of such a bridge by a sulfonyl group one increases tanning and improves resistance to light. Resistance to light is also improved by a -SO2-NH- sulfonamide sequence. Bonding groups can be put in the following order of increasing light resistance: -CH2-
Posted on: Mon, 25 Nov 2013 07:59:12 +0000