Hindi Name : Kattha
Gambier trees grow near rivers and forests. Leaves and branches can be collected after one year. Three to four harvests are done every year. Bark could also be collected but it has the effect of killing the tree.
History : Gambier was of great importance for tanning during the XIXth century. At its zenith, 49,000 tons were imported by European tanners and chemicals companies in 1896.
After the discovery of other extracts such as Quebracho and the predominance of chrome tanning in the XXth century, it became into disuse.
With the recent fashionability of Eco Friendly tannage, Gambier culture is becoming again interesting as it is one of the softer extract in the market.
We could mention here that Gambier is sometimes misused to name derivatives of cutch which grow in India and Birman. Actually this above extract belongs to Acacia Catechu family and is mainly suitable for medicine, chewing, since it will give a too strong brown shade in tanning.
Composition :
Gambier belongs to catechic group. It contains catechic, epicatechic group along with anthocyanidol which give the characteristic reddish brown shade of Gambier. Impurities are glucoside and silicate compounds which are added when the liquid Gambier is pourred into mould or to facilitate the spray dryeing.
Properties :
Gambier extract, when used alone, gives a reddish brown shaded leather with full hand, mellow touch and soft character.
The relatively high percentage of glucoside enhances the glazability of the leather and gives the advantage of avoiding grain crackiness. That’s why Gambier extract is the best solution for producing box calf, glazed kid, burnish leather.
On the other hand, full vegetable tannage with Gambier only will give too much spongy leather of strong brown color.
Another particularity of this extract is that it is an excellent auxiliary for dyes, specially the black ones.
Gambier of Acacia Catechu family is commonly used to « cut » the blue tone of black dyes and mordant the fiber of collagene to enhance the reactivity with basic dyes and the dispersion of anionic dyes.
Depending on which brand and origin used, each commercial product will highlight some special qualities of the Gambier.
Commercial Brands :
RETAN FG 211 / RETAN FG 212
: The most versatile Gambier extracts for soft retannage. The fairly content of insoluble gives a nice fullness to leather. Due to the small size of particles, RETAN FG 211 and RETAN FG 212 penetrate very fastly into the inner layer of the leather. Compared to RETAN FG 211, RETAN FG 212 has a tendency to give a softer leather.
RETAN FGC : It is harder than other qualities but still softer compared to the other vegetable extracts families. RETAN FGC gives an average softy but not stretchy leather what makes it particularly recommended for shoe upper and glazed kid. In the final stage of retanning of the wet blue leather, using 1-2 % RETAN FGC provides extra gloss as well as improvement of finishing process adhesion.
RETAN GL / RETAN GP/SP : These Gambier are specialities and high technology is required to provide such extracts in liquid form to the tannery without the formation of phlobaphene or insoluble catechin polymer.
RETAN GL and RETAN GP/SP are the best for high quality leather. They give very pleasant touch, extra gloss and could be used in finishing mixture in the case of burnish and glazed articles. RETAN GL is one of the only vegetable extract which could be used in garment and glove manufacturing as it does not affect the run.
RETAN CPCI
: These extracts belong to Acacia Catechu family. They have very good affinity for textile, natural fibers and of course leather what make them very interesting for improving levelling and yield of dyeing.
RETAN PTK / GAMBIER GPG : These are Gambier extracts which have the characteristic of increasing the viscosity of the retanning bath. They could be used to notably increase the thickness of poor leather such as baby lamb, loose kid and calf.
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