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Positive temperature coefficient material, preparation method thereof and thermistor containing positive temperature coefficient material

A positive temperature coefficient, thermistor technology, applied in the direction of resistors with positive temperature coefficient, etc., can solve the problems of low PTC strength, the thermistor cannot be used normally, and poor aging resistance.

Active Publication Date: 2012-07-11
BYD CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are mainly the following problems in the application of positive temperature coefficient materials: (1) The aging resistance of materials is poor, and when they are used repeatedly or in special environments, the performance of positive temperature coefficient materials changes greatly
It greatly limits the application stability and safety of products such as current limiting elements and heating devices
(2) The pressure resistance and current resistance performance of the thermistor made of positive temperature coefficient material cannot meet the requirements. For example, on the battery pack of electric vehicles, ordinary thermistors cannot be used normally when the normal working current is high.
This is because the working environment of the battery is harsh, and it is in a high temperature state for a long time. In addition, its working current and voltage are relatively high. The working current is generally greater than 50A, and the voltage is higher than 120V. Meet the use requirements
[0003] CN1167325 discloses the application of a kind of macromolecular positive temperature coefficient material containing nucleating agent, the composition of this material has also added a kind of nucleating agent except polymer, conductive filler and conductive filler, although improved the material resistivity Uniformity and yield, but its anti-aging performance and withstand voltage and current performance are far from meeting the requirements

Method used

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  • Positive temperature coefficient material, preparation method thereof and thermistor containing positive temperature coefficient material
  • Positive temperature coefficient material, preparation method thereof and thermistor containing positive temperature coefficient material
  • Positive temperature coefficient material, preparation method thereof and thermistor containing positive temperature coefficient material

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preparation example Construction

[0019] The invention provides a method for preparing a positive temperature coefficient material, comprising the following steps:

[0020] 1) Mix additives, nucleating agents, and polymers in an extruder and cut them into mixture I with a particle diameter of 4 mm;

[0021] 2) Fully mix the titanate-modified conductive filler and titanate-modified flame retardant in a high mixer to obtain mixture II;

[0022] 3) mixing mixture I, mixture II and lubricant in an internal mixer to obtain a positive temperature coefficient thermistor material;

[0023] Wherein, based on the total weight of the mixture I, II and the lubricant, based on the total weight of the mixture, the content of the additive is 0.5-10 wt%, and the content of the polymer is 5-15 wt%, The content of the nucleating agent is 0.5-10wt%, the content of the lubricant is 0.5-3wt%, the content of the titanate-modified conductive filler is 80-90wt%, the content of the titanate-modified flame retardant is 1- 6wt%; the a...

Embodiment 1

[0042] This embodiment is used to illustrate the preparation of the positive temperature coefficient material and thermistor of the present invention.

[0043] By mixing 2% ethylene-octene copolymer, 2% EPDM, and 10% high-density polyethylene resin that account for the positive temperature coefficient material to obtain a mixture, the mixture obtained above is sent into a twin-screw compounding extruder ( In SJSH-30 type, Nanjing Rubber and Plastic Machinery Factory), the length-to-diameter ratio of the extruder is L:D=36:1, and the screw diameter is Φ53 mm. Adjust the rotation speed of the screw to 400 rpm, and divide it into 5 sections from the feed end to the discharge end, and control the temperature of each section at: 170°C; 175°C, 180°C, 185°C, 185°C; The vacuum degree of the mixture is maintained at 0.05 to 0.08 MPa; under the above conditions, through melt extrusion and granulation, mixture I is obtained; 80% titanate modified nickel powder, 4% titanate modified magne...

Embodiment 2

[0047] Mix 0.5% ethylene-octene copolymer, 0.5% EPDM, and 15% polyethylene resin, which account for positive temperature coefficient materials, to obtain a mixture, and send the above-mentioned mixture into a twin-screw compounding extruder (SJSH- Type 30, Nanjing Rubber and Plastic Machinery Factory), the length-to-diameter ratio of the extruder is L:D=36:1, and the screw diameter is Φ53 mm. Adjust the rotation speed of the screw to 400 rpm, and divide it into 5 sections from the feed end to the discharge end, and control the temperature of each section at: 170°C; 175°C, 180°C, 185°C, 185°C; Keep the vacuum degree of 0.05 to 0.08 MPa; under the above conditions, through melt extrusion granulation, to obtain the mixture I; 82% of titanate modified carbon black, titanate modified 1% of alumina in Mix at room temperature (25° C.), first at 800 rpm for 20 minutes, then at 2000 rpm for 3 minutes to obtain mixture II. Finally, mixture I, mixture II and 1% zinc stearate were mixed ...

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PUM

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Abstract

The invention provides a positive temperature coefficient material. The material is formed by melting a mixture, and the mixture comprises a polymer, a conductive filler, a nucleating agent, an additive, a flame retardant and a lubricant; through considering the total weight of a mixture as a reference, the components by weight percent are 0.5 to 10 wt% additive, 5 to 15 wt% polymer, 0.5 to 10 wt% nucleating agent, and 0.5 to 3 wt% lubricant, 80 to 90 wt% conductive filling material, and 1 to 6 wt% flame retardant; the additive is ethylene-propylene-diene rubber; the conductive filling material is titanate modified conductive filling material; and the flame retardant is titanate modified flame retardant. The invention further provides a preparation method of the material and a thermistor containing the material. The positive temperature coefficient material has good ageing-resistance and pressure resistant and current resistance.

Description

technical field [0001] The invention relates to a positive temperature coefficient material, a preparation method thereof and a thermistor containing the material. Background technique [0002] Some polymer conductive composite materials have a positive temperature coefficient (PTC) effect, that is, the resistivity of the material increases with the increase of temperature, and the resistivity shows a sudden change of magnitude near the critical temperature. Thermistors made of polymer positive temperature coefficient materials are widely used in battery protection for mobile communication equipment, overcurrent protection for computer equipment, and other fields. However, there are mainly the following problems in the application of positive temperature coefficient materials: (1) The aging resistance of materials is poor, and when they are used repeatedly or in special environments, the performance of positive temperature coefficient materials changes greatly. It greatly l...

Claims

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Application Information

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IPC IPC(8): C08L23/06C08L23/12C08L23/16C08L23/08C08L33/04C08L27/18C08L27/12C08L27/08C08L27/16C08L27/14C08K13/06C08K9/04B29B9/06H01C7/02
Inventor 任茂林李晓芳林信平
Owner BYD CO LTD
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