Siddarmark, LLC established industrial manufacturing technology for CNT yarn which is applied to wire harness and cloth.
Starting with the seed technology developed by Professor Y. Hayashi at Okayama University, Siddarmark, LLC industrialized the unique technology to spin infinite length CNT yarn (Sugikuro® yarn) from high purity vertically aligned double-walled carbon nanotube (DWCNT) at low cost.
Sugikuro® yarn is manufactured controlling its diameter, conductivity, twist angle, surface property, and mechanical performance under the standardized QC. Although the yarn is made without any post-treatment, the electrical resistance is low at the same level as metal (mercury) and its specific strength exceeds major carbon fiber. As adopting the newly developed CNT synthesis method, the catalyst remains on the substrate almost completely. Therefore, the residual metal in the Sugikuro® yarn is below the detection limit. As a result, no abnormal current occurs inside the yarn.
Sugikuro® Electrical Metal-Plated Yarn
Using Sugikuro® yarn, we succeeded in electroplating of CNT yarn for the first time in the world by an industrial process. Sugikuro® yarn does not require any special electrolyte or process in the electroplating. Electrical conductivity is about 40% of 50 μm diameter copper alloy wire, and specific gravity 55% to the alloy wire, about 100° folding angle at which plating surface does not crack. By adjusting CNT yarn diameter and copper plating thickness it is possible to achieve higher electrical conductivity and weight reduction. You can see the durability of plating (difficulty to peel) from the EDS mapping picture below after the 2018/12/22 V11 CNT Yarn electron beam irradiation (90 eV, 200 kGy twice). It is clear that copper plating applied is quite durable, not like nonelectroplated CNT yarns reported in articles.
Sugikuro® Yarn & Cloth
Sugikuro® CNT yarns have already been applied to sensors, and the electric wire R & D has been also conducted. Despite the fact that metallic impurities are below the measurement limit and no post-treatment has been done, the electrical conductivity is 5.0 x 105 to 1.0 x 106 S / m, showing the world highest level as CNT yarn at present. In addition, the specific strength is the world highest strength of 1.8 GPa. The specific gravity is 0.1 ~ 0.3.
Production trial of CNT cloth using Sugikuro® yarn is conducted. As it is made of the pure CNT, its specific gravity is less than 1/4 of CF cloth, and its strength is equal to or higher than that, while it has higher electrical conductivity. CNT dust will not be generated except for the use by special strong friction. Please be aware of exposure precautions during processing just in case.
Sugikuro® yarn is the only DWCNT in the world that is adopted for strict safety assessment at the national laboratories in Japan and the UK.