method for modifying the physical and chemical properties of acacia mimosa pflanzenextrakts, a modified plant extract, and use of a chemically modified pflanzenextrakts

摘要

The present invention refers to a process for modification of the physical and chemical properties of a plant extract of Acacia Mimosa, for tanning and retanning of skins, comprising: (a) mixing a powdered extract of Acacia Negra with water at a ratio of about 0.5 to 2.0 kg per liter of water, preferably at a ratio of 1.0 to 1.5 kg per liter, and most preferably of 1.05 to 1.06 kg per liter; or optionally, using a solution of tannin in liquid form in a concentration of 25% to 60%, preferably in a concentration of 45% to 55%, and most preferably in a concentration of 50% of total solids content; (b) heating the mixture thus formed while vigorously stirring the same at a temperature between 50 and 100 DEG C, preferably between 67 and 98 DEG C; (c) slowly adding a sulphonation agent to the heated mixture, at a ratio by weight of about 1/100 to about 1/20 to the extract of Acacia Negra; and (d) raising the temperature of the mixture to a range between 45 to 135 DEG C, maintaining a pressure between 0.2 kgf/cm2 and 7 kgf/cm2 for a period comprised between 1 and 14 hours to complete the sulphonation of the tannin.