METODO CON PROTEZIONE DELLE CONDIZIONI AMBIENTALI PER IL TRATTAMENTO CON CALCE DI PELLI GREZZE

PCT No. PCT/HU82/00009 Sec. 371 Date Oct. 29, 1872 Sec. 102(e) Date Oct. 29, 1982 PCT Filed Mar. 10, 1982 PCT Pub. No. WO82/03228 PCT Pub. Date Sep. 30, 1982.The invention relates to an environment-protecting method for the liming of raw hides, wherein, after an optional mechanical degreasing step, the hides are subjected to presoaking, chemical degreasing, washing, alkaline swelling and collapsing, enzymatic unhairing, plucking and liming, and the sulfide ions remaining in the liquor after liming are deactivated. According to the invention the raw hides are treated, prior to liming, with 0.05 to 0.50% by weight of a proteolytic enzyme with an Anson-activity of 1.2 to 1.5 in a bath of a temperature not exceeding 35 DEG C. and a pH value not exceeding 12, thereafter the hides are subjected to hair-destruction liming with a lime liquor containing not more than 2.0% by weight of disodium sulfide and/or sodium hydrogen sulfide, calculated for the weight of the raw hide, and the sulfide ions remaining in the lime liquor are oxidized directly in the liming vessel so that 100% by weight of water and at least 0.04% by weight of manganese sulfate are added to the used lime liquor in the presence of the limed hides, the hides are rotated in the liquor for at least 15 minutes, thereafter up to 1.0% by weight of technical hydrogen peroxide are added, preferably in three portions at intervals of 10 minutes, to the liquor within an additional rotation period not exceeding 150 minutes.