Thick film element having covering layer with high heat conductivity

An use of a thick film element for coating products having a single-sided heating covering layer, wherein the thick film element has a covering layer with high heat conductivity and comprises:

• a carrier;
• a thick film coating deposited on the carrier;
• and a covering layer overlaid on the coating, wherein the thick film coating is a heating material, and a mode of heating is electrical heating, wherein the carrier, the thick film coating and the covering layer are selected from a material that fulfills every of following equations:
• λ
• 1
• ⁢
• A
• ⁢
• T
• 1
• -
• T
• 0
• d
• 1
• =
• a
• ×
• λ
• 3
• ⁢
• A
• ⁢
• T
• 3
• -
• T
• 0
• d
• 3
• ,
• λ
• 2
• ⁢
• A
• ⁢
• T
• 2
• -
• T
• 0
• d
• 2
• =
• b
• ×
• λ
• 1
• ⁢
• A
• ⁢
• T
• 1
• -
• T
• 0
• d
• 1
• ,
• ⁢
• λ
• 2
• ⁢
• A
• ⁢
• T
• 2
• -
• T
• 0
• d
• 2
• =
• c
• ×
• λ
• 3
• ⁢
• A
• ⁢
• T
• 3
• -
• T
• 0
• d
• 3
• ;
• wherein 200≤a≤104, 0<b≤1000, 0<c≤5×105;
• T2<TMinimum melting point of the covering layer;
• T2<TMinimum melting point of the carrier;
• T0≤30° C.;
• wherein a value of
• λ
• 1
• ⁢
• A
• ⁢
• T
• 1
• -
• T
• 0
• d
• 1
• represents a heat transfer rate of the covering layer;
• a value of
• λ
• 2
• ⁢
• A
• ⁢
• T
• 2
• -
• T
• 0
• d
• 2
• represents a heat generating rate of the thick film coating;
• a value of
• λ
• 3
• ⁢
• A
• ⁢
• T
• 3
• -
• T
• 0
• d
• 3
• represents a heat transfer rate of the carrier;
• λ1 represents a heat conductivity coefficient of the covering layer at a temperature of T1;
• λ2 represents a heat conductivity coefficient of the thick film coating at a temperature of T2;
• λ3 represents a heat conductivity coefficient of the carrier at a temperature of T3;
• A represents a contact area of the thick film coating with the covering layer or the carrier;
• d1 represents a thickness of the covering layer;
• d2 represents a thickness of the thick film coating;
• d3 represents a thickness of the carrier;
• T0 represents an initial temperature of the thick film heating element;
• T1 represents a surface temperature of the covering layer;
• T2 represents a heating temperature of the thick film coating;
• T3 represents a surface temperature of the carrier;
• d2≤50 μm;
• 10 μm≤d1≤10 mm, d3≥10 μm;
• TMinimum melting point of the carrier>25° C.;
• and λ1>λ3.