Patent ID: 8900492

Claim:
Insulation sheets, wherein each insulation sheet comprises a homogeneous mixture of plastic materials comprising from about 40 wt % to 100 wt % of a combination of polystyrene (PS) and polyethylene terephthalate (PET) in a PS/PET weight ratio of from about 9:1 to 2:8; and from about 20 wt % to 50 wt % of high density polyethylene; and less than about 5% of other types of plastic, wherein the materials are obtained from a plurality of crushed, melt blended and compression molded post-consumer plastic articles forming the sheet which are devoid of heavy non-plastic contaminants including glass, metals and fibers and having a thickness of from about 3 to 10 mm, and exhibit a thermal conductivity k of from about 0.08 to 0.12 W/m·°K, wherein the insulation sheets are laminated together into a composite laminate structure with trapped air in between the insulation sheets by an air impermeable seal all around a perimeter of the insulation sheet or a sandwiching air-containing bag between individual insulation sheets, prepared by a process according to the following steps: A) providing a plurality of post-consumer plastic articles, said plurality comprising articles made from polyethylene terephthalate, articles made from polystyrene, and from high density polyethylene and other types of plastic; B) crushing said plurality of post-consumer plastic articles to provide a mixture of plastic flakes; C) melt-blending said mixture of plastic flakes, or further reducing the size of particles within said mixture of plastic flakes, to thereby provide a homogeneous mixture of plastic material comprising from about 40 wt % to 100 wt % of a combination of polystyrene (PS) and polyethylene terephthalate (PET) in a PS/PET weight ratio of from about 9:1 to 2:8; and from 20 wt % to about 50 wt % of the high density polyethylene; and less than about 5% of other types of plastic; and D) compression molding said homogeneous mixture of plastic material into insulation sheets having a thickness of from about 3 to 10 mm, said insulation sheets exhibiting a thermal conductivity k of from about 0.08 to 0.12 W/m·°K.