GB360371A - Improvements in or relating to the manufacture of sheet material from fibres produced from animal hides and skins - Google Patents

Abstract

Artificial leather is made by disintegrating scraps and cuttings of leather and hides, suspending the disintegrated fibres in water, neutralizing the suspension, adding a binding agent such as rubber latex, adding a catalyst to precipitate the binder on to the fibres, and subsequently separating the liquid to form a sheet of fibrous material. Where the initial material is not tanned, a tanning agent may be added prior to neutralization, and when leather scrap is used, a detanning agent is added, followed by a tanning agent. In one method, the material is first washed in water, after which a thin slurry of the fibres in aqueous suspension is made. The fibres are then neutralized and partially detanned by the addition of a mild alkali such as sodium carbonate if the fibres are vegetable tanned, or by the addition of Rochelle salts if the fibres are mineral tanned. A tanning agent such as sumach or quebracho, mineral tannin such as chrome, or a synthetic tannin, is then added, and a grease in the form of an emulsifiable oil such as sulphonated cod oil or colloidal neat's foot oil. After mixing, the slurry is again neutralized by means of an alkali. A binding material is then added, for example, rubber, guttapercha, or balata latex, or a synthetic latex. An acid catalyst such as alum, calcium chloride or an organic acid is next added to precipitate the binder on the fibres. The liquids in the slurry are then extracted in any manner, for instance by discharging it upon a screen and applying pressure or suction to produce a coherent sheet. The sheet material is then passed through pressure rolls. Dyes may be added to the slurry. In the treatment of untanned raw material, the material is washed, made into a slurry, a tanning agent and grease are added as before described, the slurry is neutralized by the addition of alkali, or by washing in water, and the binding agent is added as before. Subsequent treatment is the same as previously described.