Conductive composition exhibiting PTC behavior and over-current protection device using the same

• US 20060108566A1
• Filed: 11/04/2005
• Published: 05/25/2006
• Est. Priority Date: 11/19/2004
• Status: Abandoned Application

• Current Assignee: Polytronics Technology Corporation
• Original Assignee: Polytronics Technology Corporation
• Inventors: Tsai, Tong Cheng, Chen, Kuo Hsun, Ma, Yun Ching
• Application Number:
  US11/266,217
• Publication Number:
  US 20060108566A1
• Time in Patent Office: Days
• US Class Current: 252/500
• CPC Class Codes: H01B 1/24 the conductive material comprising carbon-silicon compounds, carbon or silicon
• CPC Class Codes: H01C 7/027 consisting of conducting or semi-conducting material dispersed in a non-conductive organic material

Abstract

The present invention discloses a conductive composition comprising a plurality of polymers and at least one conductive filler. The polymers are compatible under a molecular size and the form of the conductive filler includes a flake. The conductive composition of the present invention owns better electrical characteristics than a conventional conductive composition that comprises a single polymer. The present invention further discloses an over-current protection device comprising two metal foils and a PTC (positive temperature coefficient; PTC) composition layer. The PTC composition layer contains the conductive composition.

Claims

1. A conductive composition exhibiting PTC behavior, comprising:

a plurality of polymers, which are compatible under a molecular size; and

at least one conductive filler dispersed in the polymers, wherein the form of the conductive filler includes a flake.

2. The conductive composition of claim 1, further comprising a coupling agent that improves the resistance uniformity and processibility of the conductive composition.

3. The conductive composition of claim 1, wherein the polymers are selected from the group consisting of epoxy resin, polyethylene, high-density polyethylene, polyoctylene, polypropylene, carboxylic resin and its copolymer or the mixture thereof.

4. The conductive composition of claim 1, wherein the conductive filler is selected from the group consisting of carbon black, metal and ceramic materials.

5. The conductive composition of claim 1, wherein the conductive filler is a mixture of nickel powder and carbon black.

6. The conductive composition of claim 5, wherein the volume percentage of the nickel powder is from 23% to 33%.

7. The conductive composition of claim 5, wherein the volume percentage of the carbon black is from 5% to 25%.

8. The conductive composition of claim 2, wherein the volume percentage of the coupling agent is from 0% to 5%.

9. An over-current protection device, comprising:

two metal foils; and

a PTC composition layer, which comprises;

a plurality of polymers, which are compatible under a molecular size; and

at least one conductive filler dispersed in the polymers, wherein the form of the conductive filler includes a flake.

10. The over-current protection device of claim 9, wherein the polymers are selected from the group consisting of epoxy resin, polyethylene, high-density polyethylene, polyoctylene, polypropylene, carboxylic resin and its copolymer or the mixture thereof.

11. The over-current protection device of claim 9, wherein the conductive filler is selected from the group consisting of carbon black, metal and ceramic materials.

12. The over-current protection device of claim 9, wherein the conductive filler is a mixture of nickel powder and carbon black.