High modulus ductile thermoplastic compositions having transparency to radio frequency signals
Thermoplastic compositions include: a) from about 5 wt % to about 30 wt % of a thermoplastic polymer component including polycarbonate, polyethylene terephthalate or a combination thereof; b) from about 10 wt % to about 55 wt % of a poly butylene terephthalate component; c) from about 0.1 wt % to about 10 wt % of a polyester elastomer component; d) from 0 wt % to about 10 wt % of an acrylic impact modifier component; e) from 0 wt % to about 10 wt % of an ethylene/alkyl acrylate/glycidyl methacrylate terpolymer compatibilizer component; and f) from about 30 wt % to about 70 wt % of a ceramic fiber component. Articles formed from the thermoplastic compositions and methods of forming the articles are also described.
1. A thermoplastic composition comprising:
a) from about 5 wt % to about 30 wt % of a thermoplastic polymer component comprising polycarbonate, polyethylene terephthalate or a combination thereof;
b) from about 10 wt % to about 35 wt % of a polybutylene terephthalate component;
c) from about 0.1 wt % to about 10 wt % of a polyester elastomer component;
d) from 0 wt % to about 10 wt % of an acrylic impact modifier component;
e) from 0 wt % to about 10 wt % of an ethylene/alkyl acrylate/glycidyl methacrylate terpolymer compatibilizer component; and
f) from about 55 wt % to about 75 wt % of a ceramic fiber component,
wherein,
a molded sample of the thermoplastic composition has a tensile modulus of at least about 25 gigapascals (GPa) as determined in accordance with ASTM D638 and a tensile elongation at break of at least about 1.98% as determined in accordance with ASTM D638,
the composition has a melt volume rate (MVR) of from about 12 cm 3 /10 min to about 25 cm 3 /10 min as evaluated at 275° C. under a 5 kilogram (kg) load, and
the combined weight percent value of all components does not exceed 100 wt %, and all weight percent values are based on the total weight of the composition.
2. The composition according to claim 1 , wherein the polycarbonate is a homopolymer comprising repeating units derived from bisphenol A, a polycarbonate copolymer comprising repeating units derived from bisphenol A, sebacic acid, polysiloxane, isophthalate terephthalate resorcinol (ITR), phosphate or a combination thereof.
3. The composition according to claim 1 , wherein the ceramic fiber component has a tensile modulus of at least 150 GPa when tested in accordance with ASTM D638.
4. The composition according to claim 1 , wherein the ceramic fiber component is chopped and has a length from about 0.1 millimeter (mm) to about 12 mm.
5. The composition according to claim 1 , wherein the ceramic fiber component comprises alumina.
6. The composition according to claim 1 , further comprising a transesterification quenching agent.
7. The composition according to claim 6 , wherein the transesterification quenching agent is selected from the group consisting of: an acidic phosphate salt; a Group IB phosphate salt; a Group IIB phosphate salt; a phosphorus oxo-acid; and combinations thereof.
8. The composition according to claim 6 , wherein the transesterification quenching agent is present in an amount from greater than about 0 wt % to about 1 wt %.
9. The composition according to claim 1 , further comprising an additive material, the additive material selected from the group consisting of: an antioxidant; a colorant; a de-molding agent; a dye; a flow promoter; a flow modifier; a light stabilizer; a lubricant; a mold release agent; a pigment; a quenching agent; a thermal stabilizer; a UV absorbant; a UV reflectant; a UV stabilizer; an epoxy chain extender; a flame retardant; and combinations thereof.
10. The composition according to claim 1 , wherein a molded sample of the thermoplastic composition has a notched Izod impact strength of at least about 100 Joules per meter (J/m) as determined in accordance with ASTM D256.
11. The composition according to claim 1 , wherein the thermoplastic composition is transparent to radio frequency signals.
12. The composition according to claim 1 , wherein the thermoplastic composition is colorable in achromatic colors of black, white or gray.
13. The composition according to claim 1 , wherein the thermoplastic composition further comprises from about 0.5 wt % to about 20 wt % titanium dioxide.
14. The composition according to claim 13 , wherein a molded sample of the thermoplastic composition retains at least 80% of its tensile properties as compared to a substantially identical molded sample that does not include titanium dioxide.
15. The composition according to claim 1 , wherein the thermoplastic composition is chemically resistant.
16. The composition according to claim 1 , wherein the thermoplastic composition is flame retardant.
17. An article comprising a composition according to claim 1 .
18. The article according to claim 17 , wherein the article is extrusion-molded, injection-molded, compression-molded, thermoformed, overmolded, or insert-molded with a metallic or composite laminate insert.
19. The article according to claim 17 , wherein the article is selected from the group consisting of: a communication device; a computer device; an electromagnetic interference device; a printed circuit; a Wi-Fi device; a Bluetooth device; a GPS device; a cellular antenna device; a smart phone device; a wireless communication device; a structured media enclosure; an antenna concealing enclosure; an enclosure for networking equipment; a structural component of an electronic device; a portable computing device; a hand-held electronic device; an automotive device; a medical device; a sensor device; a security device; a shielding device; an RF antenna device; an LED device; and an RFID device.