Abstract: Composite materials comprising propylene-based copolymer coating or tie layers disposed on one or more substrates are set forth herein. In one or more embodiments, the coating compositions comprise propylene and from about 3 to about 25 wt % units derived from ethylene and/or a C4-C8 alpha-olefin, and have a melting temperature less than about 105° C. and a heat of fusion less than about 75 J/g. Processes for forming such composite materials, such as by monoextrusion or coextrusion, are also provided.