Posted: 12 January 2010 at 2:40am | IP Logged

Here I am starting first application of Herbal tanning and I prefer to start with soaking.

use of Saraka Indica Bark, at the soaking will give uniform soaking.

http://www.new.dli.ernet.in/rawdataupload/upload/insa/INSA_1 /20006186_99.pdf

Use of calotropis gigenta in lime will remove air bubbles and minimise the lime blast. This leaves and milk, will suck the air from the pelt which block the lime from penetrating through and once the blocked air is removed the fibrils will be filled with lime and even liming can take place.

The Chemical formula of  Calotropis gigantea  is C28 H 44 O

www.ias.ac.in/jarch/proca/21/00000014.pdf

 The latex ofCalotropis gigantea contains caoutchouc to a small extent. 1.3%. The resinols are best separated from the coagulum by means of acetone. The mixture consists essentially of resinols having the formula C₃₀H₅₀O and by repeated fractional crystallisation a very small yield of α-calotropeol could be obtained. The toxic principle of the latex, gigantin, contains nitrogen and sulphur and resembles uscharin in several respects, but differs from it in composition and in its behaviour on hydrolysis.

I am not having a lab to test this, and I happened to see a Road side butcher who was making drums for this Pongal Festival who was using the above said herbals.

Then I went to Library to refer old manuals and one Tamil palm leaf found a quote on this.

I wish our Leather Chemists Association to look in to this and see if adding these herbals will minimise the pollution created by the tanner!

Posted: 12 January 2010 at 7:12am | IP Logged

Herbal Tanning

For Tanning

I hereby suggesst emblica officinalis extract  followed by Pinus Deodara., These herbal barks, when penetrated in to the upholstry and fixed with Myroblem powder will give a great releif to any patients and will take away the heat in their body.

Pinus Deodara has 8% tannin and Emblica officnalis extract has 30-40% Tanins.

It will not create any allergy and if applied correctly the Leather Tanners can acheive many things.

With a good faith that some one will undertake the trails, I am posting this here after verifying so many herbal books and manuscripts.

I am ready to assist you!

Posted: 13 January 2010 at 10:53am | IP Logged

Interesting idea here.  Combination tannages did not really evolve as one would expect in that very small phenolic groups can become serious tanning agents when combined with metals, aldehydes or other linking compounds.  Therefore, many plant extracts not traditionally considered tanning agents could become useful as tanning materials, even with some considerable advantages, ie faster penetration, lighter colors, etc. 

Phenolic compounds are very common plant metabolism products. 

Posted: 13 January 2010 at 12:10pm | IP Logged

Look at page 297 of Covington's book, there is a lot more that meet the eye with combination tannages.

Divi-divi and Myrobalan ( 68 C Tc ) get to 115- 120 C in Al-Veg semi- alum tannage. but Quebracho and Wattle do not get more than 88-98 C. The other way around Veg-Al, only Wattle get up to 102 C Ts, the rest barely make it two 85 C.

Covintong reffers to  Kalleberger/Herandez work on combitation tannages, with other metals, and to me there is a general approach but can not be gereralized, each case is different , not only regarding the two component combiantion but concentration as well.

Your chrome and the burried carboxilic groups can be look at a particular case, but please do not make a dogma out of it.

Regards

Zercas 

Posted: 13 January 2010 at 1:17pm | IP Logged

While I have not read Covington and have no idea how he could screw up the Wattle/alum (or any polyvalent metal) tannage to get such low values for Ts, I find the other results fantastic and useful.  Likewise, if David's theory holds water, it can easily add another piece to the stability development to go higher, stronger and better. 

Now that is exciting!  Plus the point with Divi-Divi and Myrobalans simply scratches the surface of thousands of phenol rich plant extracts, most of which have never even been considered for tanning, that might be used.  Here the idea would be to search the rich pages of analytical work performed and published on plants around the world to focus into potential sources.  Even weak tannages such as Oak, pine and other sources historically used in desparate times or places could easily be much more effective with these modifications.

Posted: 13 January 2010 at 1:32pm | IP Logged

Yes Waldo, I saw that low value in Covington's reference, but I had to post it as I saw it. The point is that there is a large are to be explore there, and the key is penetration as you just mentioned, thus size of the veg molecule is the issue.

We have touch this before, here is the link, how come that indu paper mentions 162 C with Myrobolans? I belibe is a natural material and not an extract, could it be? Many "not tannins" molecules able to panetrate more deeply?

http://www.leatherchemists.org/forum/forum_posts.asp?TID=113 3&KW=myrobalans&TPN=1

Regards

Zercas

Posted: 13 January 2010 at 8:07pm | IP Logged

the suggestion here is may be how the pelt will react with the tannins, but the main purpose of this herbal tanning is that if the tannins are filling the fibrils of the pelt, and if a human sits on the upholstery, or wear the leather garment made out of the herbal tan will help the man. Here the tear strength or the life of the leather is immaterial.

The resin in the herbal should react with the Human skin and penetrate in to the body and react with the blood cells.

For example, we the South Indians will take festival dinners in banana leaves, when the hot Rice/ food stuff is served on these leaf, the resin in between the nerves of the leaf will melt, mix with the food and go inside which will give even digestion.

Further a patient with burn injury is made to lie on the banana leaf, so that the resin in the leaf go in to his body.

The life of the leather tanned with these herbal may be less but it should give comfort to the patients.

This is the right time to start the research on these herbal tanning.