Abstract

The behaviour of nitroccllulose hasbeenfollowed during the making up of ajoint in mechanical leather to determine those factors that influence the strength and flexibility of the joint. Deep penetration of adhesive into the leather decreased liexibility with out improving the bond strength. Penetration of adhesive into leather was favoured by:

(a) bonding when the adhesive was fluid, i.e. the open time was short
(b) high pressures
(c) a less compact fibre structure such as in chrome leather
(d) leather low in grease. Roughing the scarf surface of the leather was essential for high bond strength.

The adhesive layer bonding the two leather surfaces needs only to be thick enough to form a continuous film. Thicker layers gave less strong bonds.