US 12,291,454 B2
Production method of carbon nanotube assembly
Akiyoshi Shibuya, Tokyo (JP); and Keiichi Kawata, Tokyo (JP)
Assigned to ZEON CORPORATION, Tokyo (JP)
Appl. No. 17/760,361
Filed by ZEON CORPORATION, Tokyo (JP)
PCT Filed Feb. 15, 2021, PCT No. PCT/JP2021/005570
§ 371(c)(1), (2) Date Aug. 9, 2022,
PCT Pub. No. WO2021/172077, PCT Pub. Date Sep. 2, 2021.
Claims priority of application No. 2020-034301 (JP), filed on Feb. 28, 2020.
Prior Publication US 2023/0083267 A1, Mar. 16, 2023
Int. Cl. C01B 32/164 (2017.01); C01B 32/162 (2017.01)
CPC C01B 32/164 (2017.08) [C01B 32/162 (2017.08); C01B 2202/08 (2013.01); C01B 2202/32 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A method of producing a carbon nanotube assembly, the method is implemented for growing a carbon nanotube assembly having a specific surface area of 600 m2/g or more on a substrate having a catalyst on a surface thereof, the method comprising: carrying out formation of the catalyst including one or more of catalyst reduction, promotion of micronization of the catalyst, and improvement in a catalytic activity compared to that of the catalyst before carrying out formation and growing the carbon nanotube assembly, by using an apparatus comprising
a formation unit that implements a formation step of causing an environment around the catalyst to become a reducing gas environment, and heating at least one of the catalyst and the reducing gas;
a growth unit that implements a growth step of growing the carbon nanotube assembly by causing the environment around the catalyst to become a source gas environment, and heating at least one of the catalyst and the source gas;
a connection section that spatially connects a furnace internal space of the formation unit and a furnace internal space of the growth unit to each other;
a first conveyance unit and a second conveyance unit, wherein the first conveyance unit conveys the substrate by screw rotations in the furnace internal space of the formation unit, the second conveyance unit conveys the substrate by screw rotations in the furnace internal space of the growth unit, the first conveyance unit and the second conveyance unit are configured as a single common unit or separate units; and
a gas mixing prevention device which prevents the gas of the furnace internal space of the formation unit and the gas of the furnace internal space of the growth unit from mixing with each other, wherein
the substrate is introduced into the apparatus via a hopper,
the first conveyance unit includes a first driving device, the second conveyance unit includes a second driving device,
the first driving device is arranged on a rear stage side of the formation unit, and the second driving device is arranged on a front stage side of the growth unit,
the formation unit and the growth unit are separate components vertically spaced apart from each other and are connected in series by the connection section, and
the formation step and the growth step while continuously conveying the substrate and preventing the gas environments in the respective steps from mixing with each other.