Compositions containing thermally conductive fillers
The present invention is directed to a composition comprising a thermoplastic polymer and a thermally conductive filler package comprising thermally conductive, electrically insulative filler particles having a thermal conductivity of at least 5 W/m·K measured according to ASTM D7984) and a volume resistivity of at least 10 Ω·m (measured according to ASTM D257) and being present in an amount of at least 50% by volume based on total volume of the filler package. The present invention also is directed to coatings comprising a thermal conductivity of at least 0.5 W/m·K (measured according to ASTM D7984) and to substrates, at least a portion of which is coated with such a coating.
1 . A composition, comprising:
a thermoplastic polymer;
a thermally conductive filler package comprising thermally conductive, electrically insulative filler particles having a thermal conductivity of at least 5 W/m·K (measured according to ASTM D7984) and a volume resistivity of at least 10 Ω·m (measured according to ASTM D257) and present in an amount of at least 50% by volume based on total volume of the thermally conductive filler package; and
a dispersant, different from the thermoplastic polymer, in an amount of 0.01% by volume to 20% by volume based on total volume of the composition;
wherein the thermally conductive, electrically insulative filler particles comprise thermally stable filler particles,
wherein the composition is substantially solvent-free, and
wherein the composition has a viscosity of 1 Pa's to 750 Pa·s at a shear rate of 10·s −1 as measured by a MARS II rheometer at 80° C. using a cone plate with a diameter of 20 mm and an angle of 1°.
2 . The composition of claim 1 , wherein the composition comprises the thermally stable filler particles in an amount of at least 90% by volume based on total volume of the thermally conductive, electrically insulative filler particles.
3 . The composition of claim 1 , wherein the composition comprises a thermal conductivity of at least 0.5 W/m·K (measured according to ASTM D7984) and a leakage current of less than 0.5 mA/mm 2 (measured according to IEC 60243), a viscosity of 1 Pa·s to 700 Pa·s at a shear rate of 10 s −1 as measured by a rheometer at 80° C. using a cone plate with a diameter of 20 mm and an angle of 1° and/or a total solids content of 40% by volume to 100% by volume based on total volume of the composition.
4 . The composition of claim 1 , wherein the composition comprises the thermoplastic polymer in an amount of 1% by volume to 70% by volume based on total volume of the composition.
5 . The composition of claim 1 , wherein the thermoplastic polymer comprises an elastomeric material.
6 . The composition of claim 1 , wherein the thermoplastic polymer is substantially free of silicone.
7 . The composition of claim 1 , wherein the composition comprises the filler package in an amount of 30% by volume to 99% by volume based on total volume of the composition, further comprises thermally conductive, electrically conductive filler particles having a thermal conductivity of at least 5 W/m·K (measured according to ASTM 7984) and a volume resistivity of less than 1 Ω·m (measured according to ASTM D257) and/or further comprises non-thermally conductive, electrically insulative filler particles having a thermal conductivity of less than 5 W/m·K (measured according to ASTM 7984) and a volume resistivity of at least 1 Ω·m (measured according to ASTM D257).
8 . The composition of claim 1 , wherein the composition further comprises an additive.
9 . The composition of claim 1 , wherein the composition comprises a gap filler composition, a sealant composition, a 3D printable composition, a putty, a molding compound, a potting compound, and/or an adhesive composition.
10 . A battery assembly comprising:
a battery cell; and
a coating formed from the composition of claim 1 on a surface of the battery cell, wherein the coating, in an at least partially cured state, comprises a thermal conductivity of at least 0.5 W/m·K (measured according to ASTM D7984), comprises a leakage current of less than 0.5 mA/mm 2 (measured according to IEC 60243), maintains a temperature of the substrate that is at least 100° C. lower following exposure of the coating on the surface of the substrate to 1000° C. for a time of at least 90 seconds than a surface temperature of a bare substrate exposed to 1000° C. for the time, and/or does not smoke upon exposure of the substrate to 1000° C. for 500 seconds.
11 . A substrate comprising a coating formed from the composition of claim 1 .
12 . The substrate of claim 11 , wherein the coating, in an at least partially cured state, comprises a thermal conductivity of at least 0.5 W/m·K (measured according to ASTM D7984), comprises a leakage current of less than 0.5 mA/mm 2 (measured according to IEC 60243), maintains a temperature of the substrate that is at least 100° C. lower following exposure of the coating on the surface of the substrate to 1000° C. for a time of at least 90 seconds than a surface temperature of a bare substrate exposed to 1000° C. for the time, and/or does not smoke upon exposure of the substrate to 1000° C. for 500 seconds.
13 . The substrate of claim 12 , wherein the substrate comprises a vehicle, a part, an article, an appliance, a battery cell, a personal electronic device, a circuit board, a multi-metal article, or combinations thereof.
14 . The substrate of claim 13 , wherein the vehicle comprises an automobile or an aircraft and/or the part comprises a thermally conductive part.
15 . A gap filler formed from the composition of claim 1 .
16 . A battery assembly comprising the thermal gap filler of claim 15 .
17 . A method of treating a substrate comprising:
contacting at least a portion of a surface of the substrate with the composition of claim 1 .
18 . A method of forming an article comprising extruding the composition of claim 1 .