Liquid crystalline polymer composition
A polymer composition is disclosed that comprises a polymer matrix containing at least one thermotropic liquid crystalline polymer and at least one hollow inorganic filler having a dielectric constant of about 3.0 or less at a frequency of 100 MHz wherein the weight ratio of the at least one thermotropic liquid crystalline polymer to the at least one hollow inorganic filler is from about 0.1 to about 10 and wherein the polymer composition exhibits a dielectric constant of about 4 or less and a dissipation factor of about 0.02 or less, as determined at a frequency of 10 GHz.
1. A polymer composition comprising:
a polymer matrix containing at least one thermotropic liquid crystalline polymer, and
at least one hollow inorganic filler having a dielectric constant of about 3.0 or less at a frequency of 100 MHz,
wherein the weight ratio of the at least one thermotropic liquid crystalline polymer to the at least one hollow inorganic filler is from about 0.1 to about 10,
wherein the polymer composition exhibits a dielectric constant of 3.4 or less and a dissipation factor of about 0.02 or less, as determined at a frequency of 10 GHz, and wherein repeating units derived from aromatic dicarboxylic acids constitute from 15 mol. % to about 60 mol. % of the thermotropic liquid crystalline polymer.
2. The polymer composition of claim 1 , wherein the weight ratio of the at least one thermotropic liquid crystalline polymer to the at least one hollow inorganic filler is from about 2 to about 6.
3. The polymer composition of claim 1 , wherein the polymer composition exhibits a dielectric constant of about 3.2 or less and a dissipation factor of about 0.005 or less, as determined at a frequency of 10 GHz.
4. The polymer composition of claim 1 , wherein the thermotropic crystalline polymer is an aromatic polyester that contains repeating units derived from 4-hydroxybenzoic acid.
5. The polymer composition of claim 1 , wherein the thermotropic liquid crystalline polymer has a total amount of repeating units derived from naphthenic hydroxycarboxylic and/or naphthenic dicarboxylic acids of about 10 mol. % or more.
6. The polymer composition of claim 5 , wherein the thermotropic liquid crystalline polymer has a total amount of repeating units derived from naphthalene-2,6-dicarboxylic acid of about 10 mol. % or more.
7. The polymer composition of claim 1 , wherein the thermotropic crystalline polymer is present in an amount of about 40 wt. % or more.
8. The polymer composition of claim 1 , wherein the at least one hollow inorganic filler comprises hollow glass spheres.
9. The polymer composition of claim 8 , wherein the hollow glass spheres have an aspect ratio of from about 0.8 to about 12.
10. The polymer composition of claim 8 , wherein the hollow glass spheres have an average diameter of from about 1 micrometer to about 150 micrometers.
11. The polymer composition of claim 10 , wherein the thickness of the walls of the hollow glass spheres is about 40% or less the average diameter of the hollow glass spheres.
12. The polymer composition of claim 1 , wherein the at least one hollow inorganic filler is present in an amount of from about 5 wt. % to about 40 wt. %.
13. The polymer composition of claim 1 , wherein the polymer composition further comprises at least one dielectric filler.
14. The polymer composition of claim 13 , wherein the at least one dielectric filler comprises a fibrous filler, a particulate filler, or a mixture thereof.
15. The polymer composition of claim 13 , wherein the fibrous filler comprises a glass fiber.
16. The polymer composition of claim 13 , wherein the fibrous filler comprises wollastonite.
17. The polymer composition of claim 13 , wherein the particulate filler comprises mica.
18. The polymer composition of claim 17 , wherein the mica is modified by a fluorinated additive.
19. The polymer composition of claim 13 , wherein the at least one dielectric filler is present in an amount of from about 3 wt. % to about 40 wt. %.
20. The polymer composition of claim 13 , wherein the thermotropic liquid crystalline polymer is present in an amount about 50 wt. % or more, the at least one hollow inorganic filler is present in an amount of from about 5 wt. % to about 40 wt. %, and the at least one dielectric filler is present in an amount of from about 3 wt. % to about 40 wt. %.
21. The polymer composition of claim 1 , wherein the polymer composition further comprises a hydrate.
22. The polymer composition of claim 1 , wherein the polymer composition further comprises a polyethylene wax.
23. The polymer composition of claim 1 , wherein the polymer composition has a deflection temperature under load of about 200° C. or more at 1.8 MPa as determined in accordance with ISO 75.
24. The polymer composition of claim 1 , wherein the polymer composition has a tensile strength of about 40 MPa or more as determined in accordance with ISO 527.
25. The polymer composition of claim 1 , wherein the polymer composition has a Charpy notched impact strength of about 3 kJ/m 2 or more as determined in accordance with ISO 179.
26. The polymer composition of claim 1 , wherein the polymer composition has a density of about 2.5 g/cm 3 or less as determined in accordance with ISO 1183.
27. The polymer composition of claim 1 , wherein the polymer composition has a melt viscosity of from about 10 Pa-s to about 100 Pa-s, as determined at a shear rate of 1,000 seconds −1 and a temperature of 20° C. higher than the melting temperature of the at least one polymer.
28. The polymer composition of claim 1 , wherein the polymer composition further comprises a laser activatable additive.
29. The polymer composition of claim 28 , wherein the laser activatable additive contains spinel crystals having the following general formula:
AB 2 O 4
wherein,
A is a metal cation having a valance of 2; and
B is a metal cation having a valance of 3.
30. The polymer composition of claim 28 , wherein the spinel crystals include MgAl 2 O 4 , ZnAl 2 O 4 , FeAl 2 O 4 , CuFe 2 O 4 , CuCr 2 O 4 , MnFe 2 O 4 , NiFe 2 O 4 , TiFe 2 O 4 , FeCr 2 O 4 , MgCr 2 O 4 , or a combination thereof.
31. A molded part that comprises the polymer composition of claim 1 .
32. An electrical connector formed from the polymer composition of claim 1 .