Method for manufacturing thermosetting positive temperature coefficient thermistor and conductive adhesive therewith

Abstract

The invention relates to a method for manufacturing a thermosetting positive temperature coefficient thermistor and conductive adhesive therewith. The method comprises the following steps of: coating conductive adhesive on one side of a metal foil, eliminating solvent by roasting for 120-600 seconds at 120-200 DEG C to obtain a conductive semi-solid sheet, and controlling the gelation time of the semi-solid sheet at 170 DEG C hot plate / 70-110 seconds; oppositely superposing and sticking two semi-solid sheets with the same size at the conductive adhesive coating surfaces and carrying out hot pressing and full solidifying to form a solid sheet; and cutting the solid sheet into chips with proper size, welding conductive pins on the surfaces of the metal foils of the chips to obtain the thermosetting positive temperature coefficient thermistor. The method induces a semi-solid sheet manufacturing procedure, so that the controllability of semi-solid epoxide resin is enhanced, and finished product with low electrical resistivity, good uniformity and excellent reliability can be obtained by combining semi-solidifying degree and the hot press process.

Description

technical field [0001] The invention relates to a thermistor whose main raw material is a polymer composite material, in particular to a method for manufacturing a thermosetting positive temperature coefficient thermistor, as well as a thermosetting conductive adhesive used in the manufacturing process and its preparation. The resistance value of the finished thermistor has the characteristic of increasing with the increase of temperature. Background technique [0002] Positive temperature coefficient (positive temperature coefficient) material means that its resistivity increases with the increase of temperature. Some polymers blended with conductive fillers can be made to have a lower room temperature resistivity, and the resistivity increases as the temperature rises, and the resistivity rises sharply at a certain temperature point. Such materials, which have positive temperature coefficient properties, have been fabricated into thermistors used in overcurrent protection...

AI Technical Summary

Problems solved by technology

As we all know, thermoplastic resin is widely used as a matrix for manufacturing thermistors, but thermoplastic resin needs to be cross-linked and cured to obtain better temperature resistance effect; carbon black, graphite, carbon fiber, etc. are often used as conductive particles and resin blends , but its disadvantage is that the ideal low room temperature resistivity cannot be achieved; nickel powder can be blended with some thermoplastic crystalline polymers to produce materials with low room temperature resistivity and high positive temperature coefficient effect, but its long-term reliability is due to the fact that nickel powder is easily destroyed Oxidation and reduction, the epoxy resin and nickel powder blending system has received widespread attention because it does not require irradiation and the epoxy resin can form an anti-oxidation layer on the nickel powder after curing

[0003] In the literature, there is a technology of using epoxy and nickel powder systems to manufacture thermosetting polymer positive temperature coefficient thermistors, but there are generally few descriptions of the manufacturing process, and the resistance uniformity is mostly out of the scope of investigation. In the actual application process The uniformity of product resistance is an important indicator of inspection, which will affect the normal operation of electrical equipment and reduce the qualified rate of products in severe cases

Images