Quebracho extract

32.01 - derivahves. Tanning extracts of vegetable origin; tannins and their salts, ethers, esters and other - Quebracho extract 3201.20 - Wattle extract 3201.90 - Other 320 1.10 (A) Tanning extracts of vegetable origin. These are vegetable extracts used mainly for the tanning of hides or skins. They are general1 prepared by extraction with warm water (sometimes acidulated) fiom the vegetab e material (wood, barks, leaves, h i t s , roots, etc.) previously ground or shredded. The liquid obtained is filtered or centrifuged and then concentrated and sometimes treated with sdphites, etc. The extracts thus obtmned are liquid but may be further concentrated to paste or solid forms. All these extracts contain varying roportions of tannin as well as etc. They are generally brown, other substances such as sugar, mineral salts, organic yellow or reddish in colow. r acid!, The principal tanning extracts are those from oak, chestnut, quebracho, pines, wattle (mimosa), sumach, myrobalans, vallonia, gambier, mangrove or divi-divi. The heading does not include (a) Raw ve etable materials, whether dried, shredded, powdered or not, of a kind used primarily in the pmb;oion oftaming extracts (heading 14.04). @) Tanning extracts mixed with synthetic tanning substances (heading 32.02). (c) Residual 1 es fiom the manufacture of wood pulp, whether or not concentrated (heading 3904). (B) Tannins and their salts, ethers, esters and other derivatives. Tannins (tannic acids) are the main active constituents of vegetable tanning materials. They are obtained by extraction wth ether or alcohol from the raw vegetable materials of heading 14.04 or from the extracts covered by Part (A above. The heading aIso covers gall-nut extracts (water-extracted gall-nut m n s ) whic are of lesser strength than those extracted with organic solvents. h The heading covers tannins byrogallol and catechol tannins) whether or not containing impurities fiom the extraction process. The most common variety is gall-nut tannin (gallotannic acid). Other tannins include oak bark tannin (quercitannic acid), chestnut wood tannin (castaneotannic acid), quebracho tannin, mimosa tannin, etc. All these tannins are generally in the form of white or yellowish amorphous powders which turn brown on exposure to air. They may sometimes be in the form of scales or needle-like c stals, etc. They are used principally as mordants in dyeing, in the manufacture o inks, for the clarification of wines or beers, in pharmacy and photography. The tannates classified in this heading include those of aluminium, bismuth, calcium, iron, manganese, zinc, hexamethylenetetramine, phenazone or orexine. Other derivatives of tannins include acetyltantun and rnethyleneditannin. These derivatives are usually employed in medicine. The heading does not include : (a) Precious metal tannates or other recious metal compounds (heading 28.43) or tannin derivatives of headings 28.44 to 28.A and 28.52. @) Gallic acid (heading 29.18). (c) Tannates and other tannin derivatives of products of headings 29.36 to 29.39 or 29.41. (d) Synthetic tanning substances, whether or not mixed with natural tanning materials (heading 32.62). (e) Tannates and other tannin derivatives of proteins of headings 35.01 to 35.04, for example, casein tannate (heading 35.01), albumin tannate (heading 35.02), gelatine tamate (heading 35.03). 32.02- Synthetic organic tanning substances; inorganic tanning substances; tanning preparations, whether or not containing natural tanning substances; enzymatic preparations for pre-tanning. - Synthetic organic tanning substances 3202.90 - Other 3202.10 This heading includes : (I) Tanning products. Provided they do not constitute separate chemically defined compounds of Chapter 28 or 29, the tanning products of this heading include : (A) Synthetic organic tanning substances (sometimes known as '' syntans '9. These are roducts which, though they can be used done to tan leather to a pale colour, are more equently mixed or used in conjunction with natural tanning materials to assist their penetrahon into the skins. They include : g (1) Aromatic syntans such as condensation products of formaldehyde with henol-, cresol- or naphthalenesulphonic acids; sulphonated aromatic h drocas ons of hi h molecular weight; polysulphonamides and polyhydroxy-po yarylsulphonesu phonic acids. K f g (2) Alkylsulphonylchlorides (sometimes known as " oilbased synthetic tanning substances "). (3) Resinic tanning products, wholly or almost wholly water-soluble. These products include certain condensation products of formaldehyde with dicyandiamde, with urea or with melamine. (B) Inorganic tanning products or " mineral tannings alurmnium, iron or zirconium salts). ¶' (e.g., based on chromium, The tanning products described in paragraphs (A) and (B above remain classified in this heading even if intermixed (e.g.,. organic syntans mixe with chromium or aluminium salts) or if mixed with natural t m n g substances. d The heading Mher includes products which, in addition to their rincipal use as synthetic tanning substances, also serve subsidiary purposes (e.g., dye leveling or bleaching). (11) Artificial bates, These are complex r arations used to facilitate the removal of the interfibrillary protein and generally also #e?me in the scra ed skins, softening them and renderin them more susceptible to the subsequent action o the tanning substances. They are usua ly based on selected enzymes, on pancreatin, etc., and may be mixed with certain delirning products, or with an extender such as bran or wood flour. F f The heading excludes : (a) Residual lyes fiom the manufacture of wood pulp, whether or not concentrated (heading 38.04). (b) Finishing agents, dye carriers to accelerate the dyeing or fixing of dyestuffs and other products and preparations (for example, dressings and mordants) of a kind used in the leather industry, provided they are not principally used as tanning materials (heading 38.09).