Conductive composite materials with positive temperature coefficient effect and process for making same

A technology of conductive composite material and positive temperature coefficient, which is applied to conductive materials dispersed in non-conductive inorganic materials, etc., can solve the problems of increased material resistance at room temperature, decreased PTC strength, poor stability, etc., and achieves stable room temperature resistivity. Agglomeration, small effect

Inactive Publication Date: 2007-07-25
SHENZHEN JINKE SPECIAL MATERIALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, polymer PTC materials mainly use carbon black as conductive filler, which has the disadvantages of short life and poor stability. Changes occur in the PTC, resulting in a decrease in the strength of the PTC; on the other hand, due to the easy oxidation of carbon black, the room temperature resistance of the material gradually increases during use.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Dissolve 0.95g of high-density polyethylene in xylene, add 0.05g of multi-walled carbon nanotubes and an appropriate amount of other additives to ethanol, and ultrasonically disperse for 30min. Under the condition of ultrasonic and stirring at the same time, add the polyethylene solution to the nanocarbon In the ethanol dispersion liquid of the tube, stirring was continued all day and night, washed with ethanol, filtered and dried. After being molded into a tablet in a flat vulcanizer, it was irradiated with γ-rays with an absorbed dose of 80KGy. The PTC strength of the resulting composite was 2.8 × 10 4 .

Embodiment 2-4

[0021] The implementation method is the same as that in Example 1, except that the dosages of high-density polyethylene and multi-walled carbon nanotubes are changed, and the results are shown in Table 1.

[0022] Table 1

[0023] Example

Embodiment 5

[0025] Add 5g of multi-walled carbon nanotubes to ethanol, ultrasonically disperse for 30min, add 45g of high-density polyethylene powder and an appropriate amount of other additives to mix evenly, filter to remove most of the ethanol, and in the loose state of carbon nanotubes infiltrated by ethanol, mix with high-density polyethylene powder. Grind and disperse the polyethylene powder together until the raw material is basically dry, then put it into a vacuum oven to dry thoroughly. After that, it was melt-blended in an internal mixer, and the blend was molded into a tablet in a flat-plate vulcanizer, and then irradiated with γ-rays with an absorbed dose of 80KGy. The PTC strength of the composite is 4.9×10 6 .

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PUM

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Abstract

Disclosed is a conductive composite materials with positive temperature coefficient effect comprising conductive filler and polymer, wherein the conductive filler includes one-dimensional nano carbon having a diameter of 1-500nm, i.e. single-walled carbon nanotubes, multi-walled carbon nanotubes, carbon nanofibers or their compounds, the weight content of the one-dimensional nano carbon material is 0.1-50%, preferably 1-15%. The polymer is selected from polyethylene, polypropylene, polyvinylidene fluoride, nylon, epoxy resin, ethane-vinyl acetate copolymer, ethene-ethyl acrylate copolymer and EPT rubber.

Description

Technical field: [0001] The invention relates to the composition and preparation technology of a functional one-dimensional nanometer carbon material conductive composite material. In particular, the composition and preparation technology of a one-dimensional nanocarbon material / polymer conductive composite material with a significant positive temperature coefficient effect. Background technique: [0002] The positive temperature coefficient (PTC) effect refers to the phenomenon that the resistivity of a material increases with temperature. Materials with PTC effect (referred to as PTC materials) are widely used in self-limiting temperature heaters, overcurrent protectors, and sensors. PTC materials mainly include ceramic-based PTC materials and polymer-based PTC materials. Ceramic PTC materials are mainly composed of doped barium titanate, and the PTC transformation of barium titanate ceramics occurs near the Curie transition temperature of crystallization. Polymer-based...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08L23/00C08L27/06C08L77/00C08L63/00C08K3/04C08J3/24H01B1/24
Inventor 成会明赫秀娟英哲杜金红李峰
Owner SHENZHEN JINKE SPECIAL MATERIALS CO LTD
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