the shelf liner is a multi - layered thermoplastic composite sheet of consistent thickness , with a non - slip bottom side and a decorative top side . a decorative top sheet is fused to a top surface of a substrate layer . the substrate layer comprises a nonwoven fabric or material that is coated on both sides , and can be fully impregnated , with a foamed plasticized polyvinyl chloride . the foamed plasticized polyvinyl chloride coating on the bottom side of the substrate layer gives the shelf liner a non - slip characteristic . an interlayer of polyvinyl chloride plastisol is disposed between the top sheet and the substrate to enhance the fused bonding of the layers . a bottom surface of the substrate layer may be fully or partly covered with a bottom coating to modify the non - slip nature of the shelf liner .