Conductive liquid crystalline polymer composition
A liquid crystalline polymer composition that is thermally and/or electrically conductive and has a reduced tendency to create a static electric charge during a molding operation is provided. More particularly, the composition contains carbon fibers distributed within a liquid crystalline polymer matrix. Through the use of carbon fibers having relatively high purity, high temperature sizing agent, and/or various process parameters, molded parts can be produced having excellent characteristics while minimizing the amount of carbon fibers contained within the polymer matrix.
1. A molded part that comprises a polymer composition, the polymer composition comprising carbon fibers distributed within a liquid crystalline polymer matrix that constitutes from about 25 wt. % to about 95 wt. % of the composition, wherein carbon fibers constitute from about 0.5 wt. % to about 20 wt. % of the composition, and wherein the molded part exhibits a surface resistivity of about 1×10 14 ohms or less as determined in accordance with IEC 60093, dielectric constant of about 5 or more as determined at a frequency of 10 MHz, and dissipation factor of about 1 or less as determined at a frequency of 10 MHz.
2. The molded part of claim 1 , wherein the liquid crystalline polymer matrix is formed from a polymer that contains aromatic ester repeating units that include aromatic dicarboxylic acid repeating units, aromatic hydroxycarboxylic acid repeating units, or a combination thereof.
3. The molded part of claim 2 , wherein the polymer further contains aromatic diol repeating units.
4. The molded part of claim 1 , wherein the carbon fibers have a carbon content of about 85 wt. % or more.
5. The molded part of claim 1 , wherein the carbon fibers have a density of from about 0.5 to about 3.0 g/cm 3 .
6. The molded part of claim 1 , wherein the carbon fibers have an average diameter of from about 0.5 to about 30 micrometers.
7. The molded part of claim 1 , further comprising glass fibers, particulate filler, or a combination thereof.
8. The molded part of claim 1 , further comprising a functional compound that includes an aromatic diol, aromatic carboxylic acid, hydrate, or a combination thereof.
9. The molded part of claim 1 , wherein the carbon fibers comprise a sizing agent, the sizing agent comprising an aromatic polymer.
10. The molded part of claim 8 , wherein the aromatic polymer has a thermal decomposition temperature of at least 350° C.
11. A compact camera module comprising the molded part of claim 1 .
12. The molded part of claim 1 , wherein the carbon fibers and liquid crystalline polymer matrix are melt processed within an extruder, and wherein the carbon fibers are supplied to the extruder at a location downstream from the feed section where the liquid crystalline polymer matrix is supplied.
13. The molded part of claim 1 , wherein the molded part exhibits a surface resistivity of from about 1×10 2 to about 1×10 8 ohms as determined in accordance with IEC 60093, dielectric constant of about 10 or more as determined at a frequency of 10 MHz, and dissipation factor of about 0.5 or less as determined at a frequency of 10 MHz.