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.

An apparatus includes a process chamber, a controllable compressor for pressurizing a fluid, a pressure reducing member, an inlet for a processing agent and a controller. The process chamber is a pressure chamber. The controllable compressor pressurizes a fluid and introduces the pressurized fluid into the process chamber from a source. Further the controllable compressor controls a predefined pressure in the process chamber to reach a supercritical state of the fluid. An inlet for a processing agent facilitates introduction of the processing agent into the process chamber prior to, during, or subsequent to pressurization of the fluid. The pressure reducing member reduces the pressure of the fluid at least to reach a gaseous state subsequent to processing the leather object such that the time for reduction of pressure exceeds a predefined reduction period or the reduction of pressure does not exceed a predefined leather pressure reduction gradient.

A method for dyeing and/or retanning of leather objects includes providing a leather object. The leather object has been processed by at least a tanning process. The leather object is introduced into a process chamber. The leather object is subjected in the process chamber to a pressurized fluid. The pressure of the pressurized fluid is controlled to reach a supercritical state. The leather object is subjected to a dyeing agent and/or a retanning agent, which dyeing or retanning agent is dissolved and/or transported in the pressurized fluid for at least a predefined period of time while the pressurized fluid is in the supercritical state. The pressure is reduced in the process chamber. The leather object is removed from the process chamber. The pressure reduction is controlled over time.

Method (1) for metal-free tanning of a quantity of hide having initial weight (w), said quantity of hide being contained in a drum, wherein said method (1) comprises at least one tanning treatment (B) of said hide including at least the following operating steps: B.1 feeding aliphatic aldehyde into said drum, in a percentage ranging between about 1% and 3% by weight with respect to the initial weight (w) of said hide, optionally equal to about 2% by weight, and B.2 moving said drum for a time period of at least about 10 min, optionally approximately 20 min at an operating speed between 1 and 8 revolutions/minute, preferably comprised between 4 and 5 revolutions/minute; B.3 feeding citric acid into said drum, in a percentage ranging between about 0.1% and 0.3% by weight with respect to the initial weight (w) of said hide, optionally equal to about 0.2% by weight, and B.4 moving said drum for a time period of at least about other 10 min, optionally approximately 20 min at said operating speed; B.5 feeding aliphatic aldehyde into said drum, in a percentage ranging between about 1% and about 3% by weight with respect to the initial weight (w) of said hide, optionally equal to about 2% by weight, and B.6 moving said drum for a time period of at least about 150 min, optionally approximately 180 min at said operating speed; B.7 feeding sodium formate into said drum, in a percentage ranging between about 0.3% and about 0.7% by weight with respect to the initial weight (w) of said hide, optionally equal to about 0.5% by weight, and B.8 moving said drum for a time period of at least about 20 min, optionally approximately 30 min at said operating speed; B.9 feeding magnesium oxide into said drum, in a percentage ranging between about 0.3% and about 0.7% by weight with respect to the initial weight (w) of said hide, optionally equal to about 0.5% by weight, and B.10 moving said drum for a time period of at least about 60 min, optionally approximately 90 min at said operating speed; B.11 feeding water into said drum, at a temperature ranging between about 30 C. and about 60 C., optionally equal to about 50 C., in a percentage ranging between about 30% and 50% by weight with respect to the initial weight (w) of said hide, optionally equal to about 40% by weight, and B.12 moving said drum for a time period of at least about 100 min, optionally approximately 120 min at said operating speed; B.13 feeding aliphatic aldehyde into said drum, in a percentage ranging between about 1% and 5% by weight with respect to the initial weight (w) of said hide, optionally equal to about 3% by weight, and B.14 moving said drum for a time period of at least about 100 min, optionally appro

Method (1) for metal-free tanning of a quantity of hide having initial weight (w), said quantity of hide being contained in a drum, wherein said method (1) comprises at least one tanning treatment (B) of said hide including at least the following operating steps: B.1 feeding aliphatic aldehyde into said drum, in a percentage ranging between about 1% and 3% by weight with respect to the initial weight (w) of said hide, optionally equal to about 2% by weight, and B.2 moving said drum for a time period of at least about 10 min, optionally approximately 20 min at an operating speed between 1 and 8 revolutions/minute, preferably comprised between 4 and 5 revolutions/minute; B.3 feeding citric acid into said drum, in a percentage ranging between about 0.1% and 0.3% by weight with respect to the initial weight (w) of said hide, optionally equal to about 0.2% by weight, and B.4 moving said drum for a time period of at least about other 10 min, optionally approximately 20 min at said operating speed; B.5 feeding aliphatic aldehyde into said drum, in a percentage ranging between about 1% and about 3% by weight with respect to the initial weight (w) of said hide, optionally equal to about 2% by weight, and B.6 moving said drum for a time period of at least about 150 min, optionally approximately 180 min at said operating speed; B.7 feeding sodium formate into said drum, in a percentage ranging between about 0.3% and about 0.7% by weight with respect to the initial weight (w) of said hide, optionally equal to about 0.5% by weight, and B.8 moving said drum for a time period of at least about 20 min, optionally approximately 30 min at said operating speed; B.9 feeding magnesium oxide into said drum, in a percentage ranging between about 0.3% and about 0.7% by weight with respect to the initial weight (w) of said hide, optionally equal to about 0.5% by weight, and B.10 moving said drum for a time period of at least about 60 min, optionally approximately 90 min at said operating speed; B.11 feeding water into said drum, at a temperature ranging between about 30 C. and about 60 C., optionally equal to about 50 C., in a percentage ranging between about 30% and 50% by weight with respect to the initial weight (w) of said hide, optionally equal to about 40% by weight, and B.12 moving said drum for a time period of at least about 100 min, optionally approximately 120 min at said operating speed; B.13 feeding aliphatic aldehyde into said drum, in a percentage ranging between about 1% and 5% by weight with respect to the initial weight (w) of said hide, optionally equal to about 3% by weight, and B.14 moving said drum for a time period of at least about 100 min, optionally appro

There is provided a process for tanning animal hide comprising treating an animal hide with at least one tanning agent and exposing the treated hide to a dose of ionising radiation of from 1 to 500 kJ/kg wherein the ionising radiation is in the form of a charged particle beam.

There is provided a process for tanning animal hide comprising treating an animal hide with at least one tanning agent and exposing the treated hide to a dose of ionising radiation of from 1 to 500 kJ/kg wherein the ionising radiation is in the form of a charged particle beam.

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.