Carbon nanotube masterbatch, preparation thereof, and use in forming electrically conductive thermoplastic composition
View Patent ↗An electrically conductive thermoplastic composition is prepared by melt blending a polymer and a masterbatch of carbon nanotubes in wax having a melting point of about 45 to about 150° C. The masterbatch of carbon nanotubes in wax is more easily prepared than a conventional carbon nanotube masterbatch in high molecular weight polymer. Use of the masterbatch of carbon nanotubes in wax also improves the melt flow properties of the electrically conductive thermoplastic composition.
1. A method of forming an electrically conductive thermoplastic composition, comprising:
melt blending
about 80 to about 98 weight percent, based on the weight of the electrically conductive thermoplastic composition, of a polymer, and
about 2 to about 20 weight percent, based on the weight of the electrically conductive thermoplastic composition, of a carbon nanotube masterbatch comprising, based on the weight of the carbon nanotube masterbatch,
about 10 to about 40 weight percent of carbon nanotubes, and
about 60 to about 90 weight percent of a wax having a melting point of about 45 to about 150° C. wherein the wax comprises a fatty acid ester selected from the group consisting of glycerol monostearate, ethylene glycol montanate, glycerol montanate, pentaerythritol tetrastearate, trimethylolpropane tristearate, sorbitan tristearate, and combinations thereof.
2. The method of claim 1 , wherein the wax comprises pentaerythritol tetrastearate.
3. The method of claim 1 , wherein the polymer is selected from the group consisting of polyesters, poly(vinyl chloride)s, polystyrenes, rubber modified polystyrenes, polyolefins, polycarbonates, polyimides, polyetherimides, poly(ether ketone)s, poly(ether ether ketone)s, polysulfones, poly(arylene ether)s, poly(phenylene sulfide)s, polyamides, copolymers of styrene and acrylonitrile, copolymers of alpha-methylstyrene and acrylonitrile, copolymers of acrylonitrile and butadiene and styrene, copolymers of acrylonitrile and styrene and acrylate esters, polyacetals, thermoplastic polyurethanes, and combinations thereof.
4. The method of claim 1 , wherein the polymer comprises a poly(arylene ether).
5. The method of claim 1 , wherein the polymer comprises a poly(arylene ether) and a polyamide.
6. The method of claim 1 , wherein the polymer comprises a poly(arylene ether) and a polystyrene.
7. The method of claim 1 , wherein the polymer comprises a poly(arylene ether) and a rubber-modified polystyrene.
8. The method of claim 1 , wherein the polymer comprises a poly(arylene ether) and a polyolefin.
9. The method of claim 1 , wherein the polymer comprises a poly(arylene ether) and a poly(phenylene sulfide).
10. The method of claim 1 , wherein the polymer comprises a poly(arylene ether) and a polyester.
11. The method of claim 1 , wherein the nanotubes comprise single wall carbon nanotubes.
12. The method of claim 1 , wherein the nanotubes comprise multiwall carbon nanotubes.
13. The method of claim 1 ,
wherein the polymer comprises about 20 to about 50 weight percent, based on the weight of the electrically conductive thermoplastic composition, of a poly(arylene ether);
wherein the polymer further comprises about 30 to about 70 weight percent, based on the weight of the electrically conductive thermoplastic composition, of a polyamide;
wherein said melt blending comprises
melt blending the poly(arylene ether) and the polyamide to form a polymer blend, and
melt blending the polymer blend with the carbon nanotube masterbatch;
wherein said melt blending the poly(arylene ether) and the polyamide and said melt blending the polymer blend with the carbon nanotube masterbatch are both conducted within a single pass through an extruder.
14. The method of claim 1 ,
wherein the polymer comprises about 20 to about 50 weight percent, based on the weight of the electrically conductive thermoplastic composition, of a poly(arylene ether);
wherein the polymer further comprises about 30 to about 70 weight percent, based on the weight of the electrically conductive thermoplastic composition, of a polyamide;
wherein said melt blending comprises
melt blending the poly(arylene ether) and the polyamide to form a polymer blend,
pelletizing the polymer blend, and
melt blending the pelletized polymer blend with the carbon nanotube masterbatch.
15. The method of claim 1 ,
wherein the electrically conductive thermoplastic composition comprises about 88 to about 96 weight percent, based on the weight of the electrically conductive thermoplastic composition, of the polymer;
wherein the polymer comprises a poly(arylene ether) and a polyamide;
wherein the electrically conductive thermoplastic composition comprises about 2 to about 12 weight percent, based on the weight of the electrically conductive thermoplastic composition, of the wax;
wherein the wax comprises pentaerythritol tetrastearate; and
wherein the carbon nanotubes comprise multiwall carbon nanotubes.
16. The method of claim 15 ,
wherein the polymer comprises about 20 to about 50 weight percent, based on the weight of the electrically conductive thermoplastic composition, of the poly(arylene ether); and
wherein the polymer further comprises about 30 to about 70 weight percent, based on the weight of the electrically conductive thermoplastic composition, of the polyamide.
17. The method of claim 13 , wherein the electrically conductive thermoplastic composition comprises about 1.5 to about 8 weight percent, based on the weight of the electrically conductive thermoplastic composition, of the wax.
18. A method of forming a carbon nanotube masterbatch, comprising:
blending
about 10 to about 40 weight percent of carbon nanotubes, and
about 60 to about 90 weight percent of a wax having a melting point of about 45 to about 150° C.;
wherein all weight percents are based on the weight of the carbon nanotube masterbatch and the wax comprises a fatty acid ester selected from the group consisting of glycerol monostearate, ethylene glycol montanate, glycerol montanate, pentaerythritol tetrastearate, trimethylolpropane tristearate, sorbitan tristearate, and combinations thereof.
19. The method of claim 18 , wherein said blending comprises melt blending at a temperature about 10 to about 150 degrees centigrade above the melting point of the wax.
20. The method of claim 18 , wherein the wax comprises pentaerythritol tetrastearate.
21. The method of claim 18 , wherein the carbon nanotube masterbatch consists of the carbon nanotubes and the wax.
22. A carbon nanotube masterbatch formed by the process of claim 18 .