PROCESS FOR PREPARING COLLAGEN CONTAINING MATERIAL Russian patent published in 1994 - IPC

FIELD: leather industry. SUBSTANCE: a collagen solution is prepared from untanned leather waste products. A paste having solid particles of 0.2-0.6 mm is prepared from tanned leather waste products. The solution and the paste are mixed for 1-5 hr at a temperature not higher than 15 C till a homogeneous compound is formed. This compound has 0.1-2 wt % untanned collagen, 0.3-10 wt % tanned collagen and a pH of 2.6-5.0. The mixture is filtered to a particle size of 0.2-0.6 mm, cooled to a temperature of 0-5 C, a cross-linking agent is added in an amount of 0.15-7.0 wt % and the resulting mixture is homogenized at a temperature of not higher than 5 C. The mixture is frozen and its temperature is reduced from minus 14 to minus 75 C for 0.1-2.0 hr and kept frozen at a temperature of from minus 2 to minus 20 C for 4-24 hr. The resulting polymeric material is them defrosted and kept moistened in the air at room temperature for 6-12 hr. The polymeric material is heated to 85-105 C, cooled to room temperature, treated with an alkali-saline solution at a pH of 9-10 for 10-20 min and squeezed out to a residual moisture content of 30-40%. The material is then subjected to hot pressing and subsequently kept in the air for 12-24 hr. To make the semiproduct leather like, it can be subjected to additional leather treatment. EFFECT: improved properties of the collagen containing material. 2 cl