IMPROVED METHOD OF ANIMAL SKIN TANNING Russian patent published in 2020 - IPC C14C3/16 

FIELD: leather industry.

SUBSTANCE: method for tanning animals skins includes a first tanning step in a tanning tank containing water, at least one C₂-C₈ aliphatic dialdehyde in an amount in range of 2–30 %, at least one nonionic surfactant in an amount in range of 0.1–20 %, wherein said tanning tank has a pH in range of 1–5 and a relative density of the liquid in range of 3 to 10° Bé, bringing pH of tanning tank to pH higher than 5 and lower than or equal to 8, washing said hide to produce animal tanned hide and carrying out a second tanning step, in which the hide is placed in a tin containing water, at least one C₂-C₈ aliphatic dialdehyde in an amount in range of 2–30 %, wherein said tanning tank has a pH in range of 1–5 and a relative density of the liquid in range of 3 to 10° Bé and does not contain a non-ionic surfactant.

EFFECT: proposed method of tanning animal skins enables to obtain tanned hides, having excellent quality and high shrinkage temperature, as well as increase breaking strength of hides.

9 cl, 1 tbl, 2 ex