METHOD OF TANNING Russian patent published in 2010 - IPC C14C3/00 

FIELD: process engineering.

SUBSTANCE: proposed method comprises processing leather semi-product in tanning agent solvent with simultaneous transmission of ultrasound wave through tanning agent solution with leather semi-product. Note that prior to transmitting ultrasound waves, first, total thickness n of all leather semi-product and attenuation factor α at 1 MHz are measured, operating frequency of ultrasound is determined by the formula f=l/(α·n). Note here that electrodes are arranged along the edges of treatment bath to pass 2 to 4 A current through said electrodes.

EFFECT: deeper impregnation of semi-product specimens, reduced time of treatment.