Polymer foam sheet and barrier layer composite

A composite comprising of:

• a foamed low density polyethylene sheet of about 2 to about 20 mm in thickness, having a first surface and a second surface;
• and
• a moisture barrier layer adjacent at least one of the first and the second surfaces;
• wherein the moisture barrier layer is a single film layer comprising at least one of:
• a co-extruded thermoplastic-thermoplastic laminate film, a co-extruded thermoplastic-polyolefin vinyl acetate film, a co-extruded polyolefin-polyolefin laminate film, a co-extruded polyolefin-polyolefin vinyl acetate film, a co-extruded thermoplastic-cellulose laminate film, and a co-extruded cellulosic-polyolefin vinyl acetate film.

A method of manufacturing a composite comprising:

• heating and admixing at least one low density polyethylene resin, at least one cross-linking agent and at least one blowing agent for a period of time sufficient to form a melt suitable for forming a polymer sheet;
• extruding said melt via a flat die in the form of a continuous low density polyethylene sheet;
• continuously engaging the low density polyethylene sheet under conditions sufficient to at least partially cross-link the low density polyethylene sheet so as to provide at least partially cross-linked low density polyethylene sheet;
• continuously engaging the at least partially cross-linked low density polyethylene sheet under conditions sufficient to partially decompose the at least one foaming agent and to at least partially foam the partially cross-linked low density polyethylene sheet so as to provide an at least partially cross-linked foamed low density polyethylene sheet having substantially closed cells;
• splitting the at least partially cross-linked foamed low density polyethylene sheet, so as to provide at least two partially cross-linked foamed low density polyethylene sheets, each having a thickness of about 2 to about 20 mm and each having a first surface and a second surface;
• and
• laminating a moisture barrier layer to at least one of the first and the second surfaces of the split sheets;
• wherein the moisture barrier layer is a single film layer comprising at least one of:
• a co-extruded thermoplastic-thermoplastic laminate film, a co-extruded thermoplastic-polyolefin vinyl acetate film, a co-extruded polyolefin-polyolefin laminate film, a co-extruded polyolefin-polyolefin vinyl acetate film, a co-extruded thermoplastic-cellulose laminate film, and a co-extruded cellulosic-polyolefin vinyl acetate film.