Process for preparing insulation sheets from unseparated mixtures of post-consumer plastic articles

One or more insulation sheets, optionally laminated together, 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 optionally articles made from high density polyethylene or 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 0 wt % to about 60 wt % of high density polyethylene;
• and thereafter;
• 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.