Conductive composite material and PTC (Positive Temperature Coefficient) thermal sensitive element prepared from same

A technology of conductive composite materials and thermal elements, which is applied to conductive materials dispersed in non-conductive inorganic materials, resistors with positive temperature coefficients, layered products, etc. Poor dispersion and other problems, to achieve the effects of good electrical conductivity, good PTC strength and resistance reproducibility, and low room temperature resistivity

Inactive Publication Date: 2011-07-20
SHANGHAI CHANGYUAN WAYON CIRCUIT PROTECTION CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the limited conductivity of carbon black itself, it cannot meet the requirements of extremely low resistance
The conductive composite material with positive temperature coefficient of resistance, which uses metal powder as the conductive filler, has extremely low resistance, but because the metal powder is easy to oxidize, it is necessary to encapsulate the conductive composite material to prevent the metal powder from being oxidized in the air. The resistance of the package increases, but the volume of the encapsulated PTC component cannot be effectively reduced, and it is difficult to meet the requirements of miniaturization of electronic components.
In order to obtain an extremely low resistance value and meet the requirements of miniaturization of electronic components, metal carbide ceramic powder (such as titanium carbide) is gradually used as a conductive filler for a low-resistance positive temperature coefficient conductive composite material, but added to a conductive composite The proportion of metal carbide ceramic powder in the material is relatively large, which is not well dispersed in the polymer, so that its resistance cannot be further reduced

Method used

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  • Conductive composite material and PTC (Positive Temperature Coefficient) thermal sensitive element prepared from same
  • Conductive composite material and PTC (Positive Temperature Coefficient) thermal sensitive element prepared from same
  • Conductive composite material and PTC (Positive Temperature Coefficient) thermal sensitive element prepared from same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] The composition of the conductive composite material that prepares PTC thermosensitive element is:

[0052] (a) The volume fraction of crystalline polymer is 40%, the melting temperature is 135°C and the density is 0.952g / cm 3 high-density polyethylene;

[0053] (b) The conductive filler is titanium carbide-tantalum carbide-tungsten carbide solid solution, the volume fraction is 60%, its particle size is less than 10 μm, and the volume resistivity is 42 μΩ.cm;

[0054] (c) The coupling agent is monoalkoxy isopropyl dioleate acyloxy titanate, the volume fraction is 0.5% of the volume of the conductive filler, and the density is 0.976g / cm 3 .

[0055] Set the temperature of the torque rheometer at 180°C and the rotational speed at 30 rpm, first add the crystalline polymer and the coupling agent and banbury for 1 minute, then add the conductive filler, and then continue banbury for 20 minutes to obtain a conductive composite The material is to pass the melted and mixed ...

Embodiment 2

[0060] The steps of preparing the conductive composite material and the PTC thermosensitive element are the same as in Example 1, but the volume fraction of the coupling agent in the conductive composite material is increased from 0.5% to 1.0% of the volume of the conductive filler.

[0061] The electrical characteristics of the PTC thermal element of this embodiment are shown in Table 1.

Embodiment 3

[0063] The steps of preparing the conductive composite material and the PTC thermosensitive element are the same as in Example 1, but the volume fraction of the coupling agent in the conductive composite material is increased from 0.5% to 1.5% of the volume of the conductive filler.

[0064] The electrical characteristics of the PTC thermal element of this embodiment are shown in Table 1.

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Abstract

The invention relates to a conductive composite material and a PTC (Positive Temperature Coefficient) thermal sensitive element prepared from the same. The conductive composite material comprises the following components in parts by volume: 15-75 percent of crystalline polymer substrate and 25-85 percent of conductive filler with the particle size between 0.1 mum and 10 mum, wherein the conductive filler is dispersed in the crystalline polymer; and a coupling agent is titanic acid ester which accounts for 0.05-5 percent by volume of the conductive filler. The structural formula of the conductive composite material is (R1O)m-Ti-(OX-R2-Y)n, wherein radical R1 is alkyl, radical X is phosphoric acid easer base, radical R2 is alkyl, radical Y is acyloxy, m is more than or equal to 1 and less than or equal to 4, n is more than or equal to 1 and less than or equal to 3, and m and n are integers. The PTC thermal sensitive element prepared from the conductive composite material is formed by fixedly clamping a conductive composite material layer between two metal foils. The invention has the advantages that: the conductive material has high electric conductivity; and the PTC element prepared from the conductive composite material has very low room temperature resistivity, high PTC intensity and resistance reproducibility.

Description

technical field [0001] The invention relates to a polymer core material used in a PTC thermosensitive element, in particular to a conductive composite material with low room temperature resistivity and a PTC thermosensitive element prepared therefrom. Background technique [0002] Conductive composite materials with a positive temperature coefficient of resistance can maintain an extremely low resistance value at normal temperatures, and have the characteristics of being sensitive to temperature changes, that is, when an overcurrent or overtemperature occurs in the circuit, its resistance will instantly increase to A high resistance value makes the circuit in an open circuit state to achieve the purpose of protecting circuit components. Therefore, a conductive composite material with a positive temperature coefficient of resistance can be connected to the circuit as a material for the current sensing element. Such materials have been widely used in electronic circuit protec...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08L63/00C08L23/06C08L23/12C08L27/16C08L23/08C08L31/04C08L33/12C08L33/02C08K13/02C08K3/14C08K3/38H01B1/20H01C7/02B32B15/08
Inventor 杨铨铨刘正平刘玉堂高道华王军
Owner SHANGHAI CHANGYUAN WAYON CIRCUIT PROTECTION CO LTD
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