Abstract: A multi-layer composite made of at least one copolyamide protective layer, and at least one copolyamide barrier layer, with the protective layer placed such that it is between the barrier layer and a source of moisture. The protective copolyamide layer is composed of a partially aromatic, amorphous copolyamide of a specified composition, and the barrier layer is composed of a partially aromatic barrier copolyamide of a specified composition. This multi-layer composite is especially useful in reusable packaging systems, such as beverage bottles or containers of any kind.

Abstract: An adhesive copolyamide composition having a dry powder DSC melting point of at least 100.degree. C., a glass transition temperature above 60.degree. C., a dry powder softening point of at least 100.degree. C., preferably a water content after storage in water of more than 20% by weight, and a wet softening point of less than 100.degree.. Such compositions exhibit softening points and heat resistances in excess of 100.degree. C. and can be processed and set at substantially lower temperatures. No low molecular weight additives are required nor are any solvents necessary. The compositions are comparable in their heat-resistance, softening points, and bond strength to conventional high performance hot melt adhesives.