US Patent 8153940 Flat heater including conductive non-woven cellulose material

The invention relates to a flat heater, which is used for applications in the range of heating voltages of up to 1000 V, produces attainable powers of up to 2 kW/m2 and is characterized by the fact that the electrical resistance required for the heating is formed by an electrically conductive cellulose nonwoven. Metallic contacts which are incorporated ensure the connection of the conductive cellulose nonwoven to a voltage source. Polymer films applied on both sides provide mechanical and electrical protection and prevent the ingress of moisture into the cellulose nonwoven.