SKIN TREATMENT PROCESS Russian patent published in 2004 - IPC

FIELD: leather industry. SUBSTANCE: invention relates to treating rawstock and can be used in manufacture of leathers from bovine hides to fabricate uppers, clothes, and fancy leather ware. Method comprises retannage with chrome tanner, neutralization, filling, retannage with vegetable tanner, dyeing, and greasing. In the chrome tanner-retannage process, anionic dye in amount of 1.0-1.5% on the weight of dressed skin. Filling, retannage with vegetable tanner, and dyeing all are conducted in the same vat in a consecutive treatment manner: (i) first with aqueous solution of preparation Polinap 101 based on alkali-neutralized acrylic acid polymer with molecular weight 60000-65000 or with aqueous dispersion of preparation Polinap 101 based on alkali-neutralized acrylic acid polymer with molecular weight 30000-32000 both taken in amount 4-5% on the weight of intermediate product on conversion to solid material, conduction time being 35-40 min; (ii) then retannage with vegetable tanner; (iii) adding mixture of nafthelenesulfonate and high- molecular anionic surfactant at their weight ratio (75-99):(1-25) in amount of 2.5-3% and anionic dye in amount of 2-3% both on the weight of dressed skin and carrying out dyeing for 50-60 min. After that follow treatment with formic or acetic acid in amount of 1-2% on the weight of dressed skin and retreatment with acid to pH 3.6-3.8. EFFECT: enabled uniform filling of skin imparting high elasticity, improved hygienic properties, and increased intensity and resistance of coloration to dry and wet friction. 3 ex