Preparation method of electrically conductive composite material with positive temperature coefficient effect

Abstract

The invention discloses a making method of conductive composite material with positive-temperature coefficient effect, which comprises the following steps: (1) putting two blending polymers and conductive filler in the double-screw squeezing machine or sealed fusing machine to fuse 5-20 min with fusing temperature higher than fusing point of polymer by 10-50 deg.c; (2) moulding the blending material into film in the flat sulfurized machine.

Description

technical field [0001] The invention belongs to the field of material processing, and in particular relates to a preparation method of a conductive composite material with a positive temperature coefficient effect. Background technique [0002] A characteristic of conductive composite materials with a positive temperature coefficient (PTC) effect is that the resistivity of the material increases with increasing temperature. Conductive polymer composite material is a functional polymer material formed by adding conductive substances to high molecular polymers through dispersion compounding, lamination compounding, and formation of surface conductive films. When adding conductive fillers to the polymer matrix to prepare conductive composites, the change of the conductivity of the composites is discontinuous within a certain concentration range of conductive fillers. As the filler content increases, the resistivity decreases slowly. When the filler content reaches a certain Wh...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that the metal used as the conductive filler is easily oxidized, which will make the conductivity of the conductive material and the strength of the PTC unstable after a period of time

The disadvantage of these two methods is that the content of carbon black used exceeds 20% by mass, and the percolation threshold of the composite material system is relatively large, and the previous patent also needs to irradiate the composite material system with microwaves.

Such a high filling of carbon black will bring some adverse effects, such as increasing the melt viscosity of the system and deteriorating processing performance; reducing the impact strength of the material; carbon black particles are easy to fall off, causing pollution in the clean room, etc.

Microwave irradiation of the system increases the preparation process and increases the cost of materials