Conductive Composite and Circuit Protection Device Including a Conductive Composite

1 . A conductive composite composition, comprising:

a polymer material;

a plurality of conductive particles; and

a high melting point additive;

wherein the high melting point additive comprises at least 1% of the conductive composite, by volume of the total composition.

2 . The conductive composite composition of claim 1 , wherein the conductive composite has a resistivity of less than 10 ohm-cm.

3 . The conductive composite composition of claim 1 , wherein the polymer material is a semi-crystalline polymer.

4 . The conductive composite composition of claim 3 , wherein the semi-crystalline polymer is selected from the group consisting of thermoplastics comprising polyolefins, thermoformable fluoropolymers, copolymers of at least one olefin and at least one non-olefin, and combinations thereof.

5 . The conductive composite composition of claim 3 , wherein the polymer material is a high density polyethylene.

6 . The conductive composite composition of claim 1 , wherein the polymer material is a low melt index polymer having a melt index of less than 1.0.

7 . The conductive composite composition of claim 1 , wherein the polymer material comprises between about 30% and about 80% by volume of the total composition.

8 . The conductive composite composition of claim 1 , wherein the conductive particles comprise between about 20% and about 50% by volume of the total composition.

9 . The conductive composite composition of claim 1 , wherein the conductive particles have a resistivity of less than 10 −3 ohm-cm.

10 . The conductive composite composition of claim 1 , wherein a D50 value of the conductive particles is between 1.0 and 2.5 microns.

11 . The conductive composite composition of claim 10 , wherein particles having the D50 value of between 1.0 and 2.5 microns improve electrical performance of the conductive composite as compared to particles having a D50 value below 1.0 micron and above 2.5 microns.

12 . The conductive composite composition of claim 1 , wherein an oxidation rate of the high melting point additive is greater than an oxidation rate of both the polymer material and the conductive particles.

13 . The conductive composite composition of claim 1 , wherein the high melting point additive is selected from the group consisting of 1,2-dihydro-2,2,4-trimethylquinoline, pentaerythritol tetrakis(2-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), and combinations thereof.

14 . A method of forming a conductive composite composition, the method comprising:

providing a polymer material;

loading the polymer material with, by volume of the total composition, between about 20% and about 50% conductive particles;

loading the polymer material with, by volume of the total composition, at least 1% high melting point additive; and

crosslinking the polymer material to form a polymer matrix of the conductive composite;

wherein the crosslinking is at a dose of the equivalent of at most 80 Mrads.

15 . A circuit protection device, comprising:

a body portion comprising a conductive composite composition, the conductive composite composition comprising:

a polymer material;

a plurality of conductive particles; and

at least 1%, by volume, of a high melting point additive loaded in the polymer material; and

leads extending from the body portion, the leads arranged and disposed to electrically couple the circuit protection device to an electrical system.