TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The layers (ii) and (iii), preferably layer (i) contain a polyethene including linear low density polyethylene, low-density polyethylene medium-density polyethylene, and/or high-density polyethylene. The backsheet: has a dielectric breakdown voltage of at least 20 kV and a thickness of at least 0.25-0.7 mm; has a reduction of dielectric break down voltage of less than 1% and a reduction in elongation at break and tensile strength of less then 20% after exposed to steam at 121 degrees C and a pressure of 1 bar for 100 hours; and does not contain any layers between (i) and (ii), (ii) and (iii) or between (i), (ii) and (iii). The layers (i), (ii) and/or (iii) are co-extruded, and the polymers in the layers (i), (ii) and (iii) are crosslinked. The layers (ii) and/or (iii) contain flame retardants and/or antidripping agents. The layer (ii) contains no pigments, layer (iii) contains carbon particles. EXAMPLE - Polywhite NG 8270 W (RTM: White masterbatch containing titanium dioxide (60%) in polyethylene) (2000 g) was blended with hostalen HD 9550 F (high density polyethylene) (7500 g) and with Polybatch UV 1952 (RTM: Stabilizer masterbatch containing hindered amine light stabilizer (10%)) (500 g) in a tumble mixer at room temperature to give a top layer composition-1. Polyblack 1423 (RTM: Black masterbatch containing carbon black (40%) in polyethylene) (1000 g) was blended with hostalen HD 9550 F (8500 g) and with Polybatch UV 1952 (RTM: Stabilizer masterbatch containing hindered amine light stabilizer (10%)) (500 g) in a tumble mixer at room temperature to give back layer composition-3. Lupolen 3020K (RTM: Low density polyethylene) (9500 g) was blended with Polybatch UV 1952 (RTM: Stabilizer masterbatch containing hindered amine light stabilizer (10%)) (500 g) in a tumble mixer at room temperature to give a middle layer composition-2. The layer compositions were metered and melted with different screw extruders and fed the polymers into a Cloeren 3-layer-feed block to feed the molten stream into the positions (1)-(2)-(3) in the final melt stream. The melt stream was fed through a slot die. The co-extruded examples were made while casting from a slot die directly onto a chilled stainless steel roll without significant draw. The cooled layers were wound into a roll to give a three-layer product. The co-extruded three-layer product was subjected to electron beam radiation (295 kV with a beam current of 4 mA) to crosslink the material, and the samples were treated to obtain the back sheet.