A positive temperature coefficient thermistor and its preparation method

Abstract

The invention provides a positive temperature coefficient thermistor made from a polymer composite material containing a specific positive temperature coefficient and a preparation method of the positive temperature coefficient thermistor. The thermistor comprises a first electric conductor, the polymer composite material with the positive temperature coefficient and a second electric conductor, wherein the polymer composite material and the second electric conductor are sequentially attached to the first electric conductor. The positive temperature coefficient thermistor is characterized in that the polymer composite material with the positive temperature coefficient is prepared from the following components in parts by weight: 70-85 parts of high-density polyethylene, 25-40 parts of polypropylene, 20-35 parts of conductive filler, 4-6 parts of a coupling agent, 2-3 parts of a crosslinking agent, 1-2 parts of an anti-oxidant and 2-3 parts of a lubricating agent. The preparation method of the positive temperature coefficient thermistor comprises the following steps: putting the polymer composite material with the positive temperature coefficient between the two electric conductors, and molding into a three-layer composite core; then irradiating the composite core by an irradiation X ray, carrying out thermal treatment, and welding conducting electrodes to the two electric conductors. The positive temperature coefficient thermistor is a brand new thermistor and contains the polymer composite material with the specific positive temperature coefficient, so that the positive temperature coefficient thermistor has the characteristics of low room temperature inner resistance, high PTC intensity, good stability and the like.

Description

technical field [0001] The invention relates to a positive temperature coefficient thermistor and a preparation method thereof, in particular to a positive temperature coefficient thermistor comprising a positive temperature coefficient polymer composite material and a preparation method thereof. Background technique [0002] At present, positive temperature coefficient thermistors include positive temperature coefficient thermistors for degaussing, positive temperature coefficient thermistors for motor starting, positive temperature coefficient thermistors for overcurrent protection, positive temperature coefficient thermistors for heating, Chip positive temperature coefficient thermistor. [0003] PTC thermistors containing PTC polymer composites are a major class of PTC thermistors, and their performance is mainly affected by the PTC properties of the PTC polymer composites they contain. For thermistor composite materials, it is generally desired to have as low as possib...

AI Technical Summary

Problems solved by technology

The positive temperature coefficient polymer composite material filled with carbon black has the characteristics of adjustable electrical conductivity in a wide range, easy molding, and low cost; but the existing problems are high room temperature resistivity and poor stability of the PTC effect, resulting in PTC strength. And the output power attenuation is too fast, the leakage current is large after protection, etc.

However, the positive temperature coefficient polymer composite material with metal particles as conductive fillers, because the metal particles are always rigid particles during the phase transition process of PTC temperature rise, does not undergo phase transition, resulting in a more serious negative temperature resistance effect during the continuous temperature rise process ( NTC); the appearance of NTC phenomenon not only irreversibly changes the electrical properties of the positive temperature coefficient material, but also causes the material to fail due to high temperature during the use of the material, or even catch fire

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