PROCESS FOR MAKING LEATHER FROM FISH SKINS Russian patent published in 2001 - IPC

FIELD: leather industry. SUBSTANCE: process involves soaking-defatting, liming with calcium hydroxide (25-30 g/cu.dm) and sodium sulfite (2-3 g/cu. dm), deashingdefatting, softening, pickling, tannage with chrome tanner, enzyme treatment combined with defatting, neutralization, dyeing, fattening, fixation of dye and fattening materials on derma fiber. Ashing and tannage are performed in two steps. In the first ashing step, fish skins are treated with sodium sulfite solution for 5-6 h, and, in the second step, mixture of vegetable and synthetic tanners at ratio (3-3.2):7 is used with total tanner concentration 45-55 g/cu.dm. EFFECT: optimized use of ash liquid and accelerated its clarification with no loss in quality of finished leather. 2 cl, 2 tbl