Synthetic fibrous materials which may be used as the substrate include those made from polyamides, such as poly(hexamethylene adipamide), poly(hexamethylene sebacamide), polycaproamide, and copolyamides, polyesters and copolyesters such as condensation products of ethylene glycol with terephthalic acid, ethylene glycol with 2. /100 mixture of terephthalic/isophthalic acids, ethylene glycol with a