Conductive masterbatches and conductive monofilaments
The present invention relates to a polyester matrix powder comprising a polybutylene terephthalate, a homogeneously dispersed carbon nanotube powder, a dispersant and a chain extender; to a conductive masterbatch with homogeneous and smooth surface; to a process for the preparation of the conductive masterbatch; to a conductive monofilament prepared from the conductive masterbatch; to a process for the preparation of the conductive monofilament; and to a fabric article prepared from the monofilament. The present invention is characterized in the preparation of carbon nanotube-containing fiber materials with higher conductivity and the improvement of the spinning property of the conductive masterbatches to avoid blocking and yarn breakage during the spinning process.
1. A polyester matrix powder containing a homogeneously dispersed carbon nanotube powder, comprising:
A) 80 to 99.5 wt. % of a polyester polymeric matrix based on a polybutylene terephthalate (PBT) or the copolymer thereof, based on the weight of polyester matrix powder,
B) 1 to 15 wt. % of a carbon nanotube powder milled at ultrahigh speed, based on the weight of polyester matrix powder,
C) 0.01 to 6.0 wt. % of a dispersant, based on the weight of polyester matrix powder,
D) 0.01 to 6.0 wt. % of a chain extender, based on the weight of polyester matrix powder;
wherein components A), B), C) and D) are mixed by means of a high-speed powder mixer to obtain a polyester matrix powder;
wherein the chain extender is selected from the group consisting of a diisocyanatocycloalkane and an oxazoline;
wherein the oxazoline is selected from the group consisting of a diisocyanatocyclohexane, a bis-oxazoline, 1,4-phenylene bis-oxazoline, 2,2′-methylene[(4,s)-4-tert-butyle-2-oxazoline] and 2,2′-methylene[(4,s)-4-phenyl-2-oxazoline].
2. The polyester matrix powder according to claim 1 , wherein the polybutylene terephthalate or the copolymer thereof in component A) is selected from the group consisting of a polybutylene terephthalate homopolymer, a copolyester having a repeat unit of butylene terephthalate (BT) and a block copolymer having a unit of polybutylene terephthalate, and the combination thereof.
3. The polyester matrix powder according to claim 2 , wherein the polyester polymeric matrix is based on a polybutylene terephthalate homopolymer.
4. The polyester matrix powder according to claim 1 , wherein the polybutylene terephthalate or the copolymer thereof has an intrinsic viscosity (I.V.) of more than 0.6 dl/g.
5. The polyester matrix powder according to claim 4 , wherein the polybutylene terephthalate or the copolymer thereof has an intrinsic viscosity (I.V.) in a range of 0.6 to 1.3 dl/g.
6. The polyester matrix powder according to claim 5 , wherein the polybutylene terephthalate or the copolymer thereof has an intrinsic viscosity (I.V.) in a range of 0.8 to 1.3 dl/g.
7. The polyester matrix powder according to claim 1 , wherein the polyester polymeric matrix is in an amount of 84 to 99 wt. %, based on the weight of polyester matrix powder.
8. The polyester matrix powder according to claim 7 , wherein the polyester polymeric matrix is in an amount of 88 to 97 wt. %, based on the weight of polyester matrix powder.
9. The polyester matrix powder according to claim 1 , wherein the carbon nanotube powder prepared via ultrahigh-speed milling has a length (L) of less than 3.0 μm and an L/D value of more than 100.
10. The polyester matrix powder according to claim 1 , wherein the milled carbon nanotube powder has a length (L) of 0.7 to 3.0 μm and an L/D value of 100 to 300.
11. The polyester matrix powder according to claim 1 , wherein the milled carbon nanotube powder is formed from a carbon nanotube with an average tube diameter of 0.5 to 50 nm (nanometer) or with an L/D value of 60 to 600.
12. The polyester matrix powder according to claim 1 , wherein component B) is in amount of 1 to 10 wt. %, based on the weight of polyester matrix powder.
13. The polyester matrix powder according to claim 12 , wherein component B) is in an amount of 2.5 to 10 wt. %, based on the weight of polyester matrix powder.
14. The polyester matrix powder according to claim 13 , wherein component B) is in an amount of 3 to 10 wt. %, based on the weight of polyester matrix powder.
15. The polyester matrix powder according to claim 1 , wherein the dispersant is an ethylene-acrylic copolymer.
16. The polyester matrix powder according to claim 15 , wherein the dispersant is ethylene-acrylic acid copolymer.
17. The polyester matrix powder according to claim 1 , wherein the dispersant is in an amount of 0.1 to 2.0 wt. %, based on the weight of polyester matrix powder.
18. The polyester matrix powder according to claim 17 , wherein the dispersant is in an amount of 0.2 to 1.5 wt. %, based on the weight of polyester matrix powder.
19. The polyester matrix powder according to claim 1 , wherein the oxazoline is 2,2′-methylene[(4,s)-4-tert-butyle-2-oxazoline] or 2,2′-methylene[(4,s)-4-phenyl-2-oxazoline].
20. The polyester matrix powder according to claim 1 , wherein the chain extender is in an amount of 0.1 to 1.0 wt. %, based on the weight of polyester matrix powder.
21. The polyester matrix powder according to claim 20 , wherein the chain extender is in an amount of 0.1 to 0.8 wt. %, based on the weight of polyester matrix powder.
22. Conductive masterbatches, which are prepared from the polyester matrix powder according to claim 1 .
23. The conductive masterbatches according to claim 22 , wherein the resistance of conductive masterbatches is in a range of 10 0 to 10 8 Ω/sq.
24. The conductive masterbatches according to claim 23 , wherein the resistance of conductive masterbatches is in a range of 10 0 to 10 5 Ω/sq.
25. A conductive monofilament, which is formed from the conductive masterbatches according to claim 22 .
26. The conductive monofilament according to claim 25 , wherein the fiber diameter of the conductive monofilament is in a range of 0.05 to 1.0 mm.
27. The conductive monofilament according to claim 26 , wherein the fiber diameter of the conductive monofilament is in a range of 0.1 to 0.5 mm.
28. The conductive monofilament according to claim 25 , wherein the conductive monofilament has a volume resistance in a range of 10 4 Ω·cm or less, a strength of 0.8 gf/d or more and an elongation of 10% or more.
29. The conductive monofilament according to claim 28 , wherein the conductive monofilament has a volume resistance in a range of 10 1 to 10 3 Ω·cm, a strength of 1.0 to 4.0 gf/d and an elongation of 10 to 70%.
30. Textiles comprising the monofilament according to claim 25 .
31. The textiles according to claim 30 , wherein the textiles have a surface resistance of less than 10 5 Ω/sq.
32. The textiles according to claim 31 , wherein the textiles have a surface resistance of 10 1 to 10 5 Ω/sq.
33. A process for the preparation of a conductive monofilament comprising the steps:
1) providing conductive masterbatches,
2) placing the conductive masterbatches at a temperature of 110 ° C. and baking over a period of 6 to 30 hours to obtain dried conductive masterbatches,
3) feeding the dried conductive masterbatches into a single screw extruder and extruding at a processing temperature of 250 to 285° C. and at a screw speed of 20 rpm, and then extruding through a filter with 60 μm screen, followed by spinning via a spinning nozzle with a pore diameter of 0 5 mm and a length of 1 mm to obtain a spun filament,
4) cooling the spun filament from step (3) at a cooling rate of 5 to 30 m/min through a cooling device and then winding at a winding rate of 40 to 100 m/min to form a conductive monofilament;
wherein the conductive masterbatches are prepared from a polyester matrix powder containing a homogeneously dispersed carbon nanotube powder, comprising:
A) 80 to 99.5 wt. % of a polyester polymeric matrix based on a polybutylene terephthalate (PBT) or the copolymer thereof, based on the weight of polyester matrix powder,
B) 1 to 15 wt. % of a carbon nanotube powder milled at ultrahigh speed, based on the weight of polyester matrix powder,
C) 0.01 to 6.0 wt. % of a dispersant, based on the weight of polyester matrix powder,
D) 0.01 to 6.0 wt. % of a chain extender, based on the weight of polyester matrix powder,
wherein components A), B), C) and D) are mixed by means of a high-speed powder mixer to obtain a polyester matrix powder.