Abstract: A recycling process for achieving near-zero emissions of tannery effluent is characterized in that effluent recycling is carried out independently in soaking, liming, re-liming, de-liming bating, pickling chrome tanning, re-tanning, neutralizing, and dyeing procedures. The effluents in the above procedures can be recycled in each step. This process greatly reduces effluent discharge and helps solve the problem of tanning pollution. The process also improves the quality of the finished leather, effectively decreases loose grain rate and increases compactness and fullness of the finished product. The project can reduce chemical material consumption by 15%-55%. For example, the consumption of chromium powder can be reduced up to 65%. Consumption of other chemical materials can be reduced by more than 90%, while certain chemical materials can be essentially completely conserved.

Abstract: D-Isoascorbic acid or one of its salts, as such or as a constituent of a liquid or solid formulation, is an effective agent for reducing the amount of Cr(VI) compounds in leathers tanned with Cr(III) salts by treatment of the leather in an aqueous liquor after tanning or finishing or of a commodity article with an aqueous solution.

Abstract: A process for retanning leather has been found, which is characterized in that a) a tanned leather is treated in aqueous liquor in the presence of hollow microspheres filled with blowing agent, b) the leather obtained according to a) is dried after further optional retanning steps and c1) treated with steam at 80 to 120° C., in particular at 80 to 100° C., or c2) with infrared radiation having a wavelength of 0.7 to 100 ?m, it also being possible for a finishing step b1) and/or a milling step b2) to follow at a time after the drying step b).

Abstract: This invention is related to the manufacturing process of the modified chromium sulphate used in the tanning process of the animal hides, and chromium tanning process performed by using the said chemical. This invention develops Manufacturing processes of chromium tanning chemical which do not require pickling and basification; Chromium and tanning chemical produced according to this process; and Chromium tanning processes which use the said chemical and do not require pickling and basification. As a result of the reaction of the chromium salts mentioned in the invention with mono and dicarboxyllic acids or salts of these acids, characteristics of the chromium salts change; thereby the invention provides benefits such as the elimination of the pickling and the basification process, minimization of the waste treatment burden and acceleration of the said processes in the tannery.

Abstract: The present invention is related to the use of a new conditioning agent for treating pelts for tanning. This conditioning agent consists in a composition of modified aldehydes, carboxylic acids or polycarboxylic acids and additives. The conditioning agent is used for replacing the steps of deliming and pickling in the pelts treatment. The action of the product can eliminate the step of basification when the tanning is made with chromium salts. The objective of the present invention is the use of a novel composition that can replace the steps of deliming, step 6, and pickling, step 8, described before for one just step called conditioning The proposed system, neutralizes the alkalinity and hence removes the solubility of Calcium from the liming operation attached in the pelt.

Abstract: A formulation and process for making a formulation for leather tanning using highly complexed Chrome III salts coupled with polymer complexing agents of medium and low molecular weight in the range of 500 to 10,000. Complexing polymers can contain vinylic acid/ester co-polymers, polyamine/polyamide co-polymers and polymers condensed from saturated carbon linked aromatic groups based on phenol and naphthalene sulfonates or other aromatic rings.

Abstract: The present invention provides an improved pickling and bating free process suitable for both hides and skins for making chrome tanned leathers by using a mixture of conventional chrome tanning salt and alkali metal salt is used at a pH in the range of 5–5.5.

Abstract: A mixture of THP and a moderator is used to tan leather. The moderator is selected from metaphosphates and polyhydroxy or polypyrolidyl compounds such as glycerol, carboxydrates PVA or PVP.

Abstract: THP and chrome are synergistic tanning agents. The combination of THP with small amounts of chrome and optionally non-ionic and/or cationic surfactants gives increased area yield and shrink temperature compared with THP, and reduced environmental impact compared with chrome. It is possible to combine degreasing, pre-tan and main tan in a single step.

Abstract: A method for producing leather generally including the steps of: (a) providing wet blue, full grain skins, (b) applying a liquid chrome solution to the skins while at a pH of 3.5 or lower, (c) raising the pH level of the skins to at least approximately 6.0 or above, (d) retaining the skins with a vegetable tanning agent, (e) introducing the skins to a dye bath, (f) introducing lubricants into the dye bath, (g) fixing the dyestuff and lubricants in the skins while reducing the pH level to the range of 3.3-3.8, (g) introducing the skins to a second dye bath, (h) fixing the dyestuff while reducing the pH level to a range of 3.0-3.5, (i) introducing the skins to a float containing a waterproofing agent, (j) fixing the waterproofing agent while reducing the pH level to approximately 3.0, (k) capping the skins to remove emulsifiers, and (1) introducing the skins to a bath containing flame resistant agents.