A co-solvent free, alcohol free thermoplastic polyamide resin body consisting essentially of from 35% up to 70% by weight of said polyamide resin body of a volatile substance selected from the group consisting of perfume oils, insecticides, odorants, bactericides and animal repellents, the remainder of said thermoplastic polyamide resin body being a fatty polyamide which is a reaction product of ethylene diamine and polymeric fat acids at temperatures in the range of 150.degree.-300.degree. C. employing essentially 1 molar equivalent of amine per molar equivalent of carboxyl group, said polymeric fat acids being polymerized monocarboxylic aliphatic acids having from 8 to 24 carbon atoms, and said polymeric fat acids having a dimeric fat acid content and a ratio of trimeric:
- monomeric fat acids defined substantially within the area ABC of FIG. 5, said fatty polyamide softening in the range of 10.degree.-15.degree. C. on being heated within the range of 120.degree. C. up to 400.degree. C. and having a sharp decrease in viscosity at temperatures above its softening range, said fatty polyamide having a molecular weight within the range between about 9,000 and 12,000, said resin body being a solid solution.