A method is provided for producing sustainable leather using by-products from parts of all varieties and species of the plant genus Persea including among them both the American species and the Hass variety. A hide or leather may be produced by the method, and a method is provided for producing the natural tanning agents used in the method to produce sustainable leather and the natural tanning agents produced by the method.

The present invention describes a fully bio-degradable probiotic composition and its method of use as leather tanning auxiliary to offer a green technology to reduce waste and increase the value of by-products reducing the need of synthetic chemicals and improving the quality of effluents. Probiotics or beneficial microorganisms are used to obtain biochemicals through a controlled fermentation of natural ingredients. The result of the process is a consortium of metabolites used in conjunction with probiotic bacteria wherein product has properties very similar to traditional leather auxiliaries extensively used during the leather making process, such as wetting, dispersing, degreasing and solubilizing agents. Therefore, they have clear applications not only in the beam house operations, but also in wet-end and finishing.

Modified polylactones, aqueous compositions including them, as well as their use and methods including their use as fatliquoring agents (fatliquors) in the treatment of leathers, including other embodiments.

Modified polylactones, aqueous compositions including them, as well as their use and methods including their use as fatliquoring agents (fatliquors) in the treatment of leathers, including other embodiments.

A method for tanning an animal substrate comprising the steps: i) agitating the animal substrate with a chromium-free tanning agent; and ii) agitating the animal substrate with a tanning agent having an oxazolidine group; wherein at least some of the agitation is performed in the presence of a solid particulate material having an average particle size of from 1 to 500 mm.

A method for tanning an animal substrate comprising the steps: i) agitating the animal substrate with a chromium-free tanning agent; and ii) agitating the animal substrate with a tanning agent having an oxazolidine group; wherein at least some of the agitation is performed in the presence of a solid particulate material having an average particle size of from 1 to 500 mm.

A process for leather production from a raw animal hide includes the steps of pre-soaking, soaking, unhairing and liming, re-liming, deliming and bating, pickling and tanning, degreasing, re-tanning, neutralizing, dyeing and fatliquoring, and washing the processed hide. Waste liquid is collected from at least one of the foregoing steps is recycled to at least one of the foregoing steps. The collected waste liquid can be recycled to the same step, to a different step, or to two of more steps in the process.

A process for leather production from a raw animal hide includes the steps of pre-soaking, soaking, unhairing and liming, re-liming, deliming and bating, pickling and tanning, degreasing, re-tanning, neutralizing, dyeing and fatliquoring, and washing the processed hide. Waste liquid is collected from at least one of the foregoing steps is recycled to at least one of the foregoing steps. The collected waste liquid can be recycled to the same step, to a different step, or to two of more steps in the process.

A method for tanning animal skin may include: putting the animal skin in contact with a first tanning bath comprising (weight percentages referring to a pelt weight of the animal skin): water, at least one C.sub.2-C.sub.8 aliphatic dialdehyde in a quantity within a range of 2%-30%, and/or at least one non-ionic surfactant in a quantity within a range of 0.1%-20%, wherein the first tanning bath has a pH within a range of 1-5 and a density within a range of 3 B-10 B; bringing the pH of the first tanning bath to a pH greater than 5 and less than or equal to 8; and/or washing the animal skin to obtain a tanned animal skin.

A method for tanning animal skin may include: putting the animal skin in contact with a first tanning bath comprising (weight percentages referring to a pelt weight of the animal skin): water, at least one C.sub.2-C.sub.8 aliphatic dialdehyde in a quantity within a range of 2%-30%, and/or at least one non-ionic surfactant in a quantity within a range of 0.1%-20%, wherein the first tanning bath has a pH within a range of 1-5 and a density within a range of 3 B-10 B; bringing the pH of the first tanning bath to a pH greater than 5 and less than or equal to 8; and/or washing the animal skin to obtain a tanned animal skin.