Polymer-carbon nanotube-carbon black composite temperature self-regulating positive temperature coefficient (PTC) electric heating material

Abstract

The invention discloses a polymer-carbon nanotube-carbon black composite temperature self-regulating positive temperature coefficient (PTC) electric heating material. The polymer-carbon nanotube-carbon black composite temperature self-regulating PTC electric heating material has positive temperature coefficients and high PTC intensity. The polymer-carbon nanotube-carbon black composite temperature self-regulating PTC electric heating material comprises: by weight, 35 to 75% of one or more of high-density polyethylene, low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, nitrile rubber buna, epoxy resins and polyvinylidene fluoride, 15 to 55% of carbon black and carbon nanotubes, 3 to 12% of an inorganic filling material, and 0.02 to 0.1% of an antioxidant. The above raw materials are mixed, then are subjected to processing molding by a banbury or a double-screw extruder, and are subjected to radiation crosslinking to form the polymer-carbon nanotube-carbon black composite temperature self-regulating PTC electric heating material with high PTC intensity. The polymer-carbon nanotube-carbon black composite temperature self-regulating PTC electric heating material has high PTC intensity and thus a leakage current is low and security and heat stability are good. In an electric warming respect, the polymer-carbon nanotube-carbon black composite temperature self-regulating PTC electric heating material is widely utilized in the fields of temperature self-regulating heaters, over-current protection and temperature sensors.

Description

Technical field: [0001] The invention relates to a high positive temperature coefficient high PTC strength self-control temperature high molecular polymer composite conductive heating material, specifically, a high PTC strength conductive composite material is prepared by using carbon black and carbon nanotubes as conductive fillers, the composite material It is especially suitable for the fields of preparing electric heating, self-temperature-controlling heating devices and the like. Background technique: [0002] PTC material is a conductive thermistor material with a positive temperature coefficient (Positive Temperature Coefficient), which has the characteristics of a huge mutation in the resistance value (the resistance value increases by at least 3 orders of magnitude) within a certain temperature range. [0003] PTC materials are divided into two categories, one is ceramic PTC materials, and the other is polymer-based PTC materials. Polymer-based PTC materials, due t...

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Problems solved by technology

The conductive mechanism of polymer PTC is generally considered to be the result of the combined effect of conductive particle contact conduction and interparticle tunnel conduction mechanism. Carbon black is selected as a conductive filler alone to obtain low volume impedance (less than 0.5Ω.cm) and high PTC strength (greater than 10 5 ) is very difficult, and carbon nanotubes are selected as conductive fillers alone, and the mass percentage of carbon nanotubes that needs to be filled is more than 20%. Powder-filled polymers, due to the high density of metals, are easy to deposit and unevenly dispersed, and the metal particles are easy to oxidize, and the material properties are not stable

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