Process and apparatus for spectroscopic identification and sorting of barrier materials

−1An apparatus and process that makes use of spectral information in the mid-infrared range (400 to 4500 cm) to identify recyclable materials containing barrier polymers from recyclable materials not containing barrier polymers, which includes projecting light containing the mid-infrared (MIR) range onto materials to be analyzed, dispersing the MIR light that has reflected from or passed through the materials or both into various wavelengths, measuring the intensity of the MIR light at least one wavelength responsive to differences between the materials, measuring the intensity of the MIR light at least one wavelength not responsive to differences between the materials in order to provide a reference, and comparing the measurements in order to identify barrier materials from non-barrier materials.