METHOD OF MANUFACTURING NATURAL PILE LEATHER Russian patent published in 2004 - IPC

FIELD: leather industry. SUBSTANCE: invention relates to manufacturing natural pile leather from bovine hides and is designed for fabrication of uppers, clothes, and fancy leather ware. Method comprises retannage of intermediate product with chrome tanner, neutralization, filling with acrylic polymer, retannage with vegetable tanner, dyeing by anionic dyes, greasing, treatment with formic or acetic acid, and rinsing. Filling, retannage with vegetable tanner, and dyeing are carried out at 40-45 C and liquid coefficient 0.9-1.0 by consecutive treatment: (i) with aqueous solution of preparation Polinap 101 based on alkali-neutralized acrylic acid polymer with molecular weight 60000-65000 and vegetable tanner both in concentration 3-4% on the weight of intermediate product; (ii) adding mixture of nafthelenesulfonate and high-molecular anionic surfactant at their weight ratio (75-99): (1-25) in amount of 2.5-3% on the weight of intermediate product; (iii) dyeing; (iv) treatment with aqueous solution of preparation Polinap AD based on cationic polyacrylamide with molecular weight 30000-32000 in amount 1.5-2.5% on the weight of intermediate product; and (v) treatment with formic or acetic acid to pH 3.6-3.8. EFFECT: improved elastoplastic properties and increased intensity and stability of coloration. 4 ex