Such products are usually greasy substances which have the undesirable side-effect of plasticizing and softening the coat on which they are used. The selection of feel modifiers, which are auxiliaries of great importance, should be made considering above all the degree of reduction in resistance that they might cause. FENlCE's feel modifiers give a delicate, mellow and persistent result to finished leather, rendering it more natural, without noticeably softening the finishing film. Cases arise in which poor rub resistance is due to the excessive use of dyestuffs in the final coats, or to inadequate fixation. It is, of course, essential to check that the finishing coats and their components contain the minimum quantities possible of plasticizing oils and surfactants.
Poor solidity is also attributable at times to the use of excessively soft polymers.
This situation may be rectified by using them together with firmer binders, either protein or synthetic. Insufficient adhesion to the leather or between the various finishing layers, caused by excessive plating or heavy use of waxes and other release agents in the lower layers may also give rise to poor rub resistance. As a general principle it is wise to avoid spray applications over coats which have been applied with a pad and then plated. This method also avoids poor levelling and other application defects. When intermediate plating is necessary, with the risk of poor subsequent anchorage due to the nature of the coats used, it is advisable to reduce the temperature and duration of the plating.