March 26, 2021
Notice Regarding Development of Conductive Inkfor Ink Jet Printing Using Copper Nanoparticles

Taiyo Nippon Sanso Corporation (“TNSC”) hereby announces that it has successfully developed
conductive ink using copper nanoparticles which can be applied to ink jet printing for printed electronics.
1. Background
Printed electronics is a technology that uses conductive ink or paste containing copper or silver, which
are highly conductive, to form conductive wiring in electronic components through printing technology.
Etching technology*, the traditional method used for forming conductive wiring, requires a great
number of complicated processes that generate a large amount of waste. Since this method poses a
significant burden on the environment, printed electronics are attracting attention for being simpler andmore environmentally friendly. Some examples of these printing technologies include screen printing
and gravure printing, and in particular, ink jet printing that uses conductive ink is attracting a high levelof interest as a technology that can support rapid model changes to electronic components and various
types of small-quantity production as it does not require a printing plate.
2. Overview of Conductive Ink for Ink Jet Printing Using Copper Nanoparticles
TNSC possesses metallic nanoparticle synthesis technology which relies on its uniquely developed
oxygen combustion technology.
The copper nanoparticles (a dried powder) synthesized in this process have a particle size of approx.
100 nm and are coated with a surface layer of copper oxide. Unlike particles synthesized through thetypical wet process, these have no organic protective coating, so there is very little outgassing when theparticles are sintered. In addition, they allow for low-temperature sintering. Up until now, TNSC hasdeveloped conductive paste that is expected to be used in RF tags, micro wiring, pressure sensors, andother applications.
By using copper nanoparticles and optimizing the composition of dispersing agents and solvents, wehave now developed conductive ink suitable for ink jet printers. The copper nanoparticles within the
conductive ink are held in a dispersed state over long periods of time, and can therefore be discharged
from the ink jet printer without clogging the nozzle, making it possible to print micro wiring patterns.
Additionally, conductivity can easily be demonstrated with photonic curing technology utilizing xenon
lamps, etc. This conductive ink is expected to be used in applications such as touch panels fortransparent conductive films and conductive wiring for organic LED lights using ink jet printing.
Specifications of Conductive Ink Using Copper Nanoparticles
Item

Specifications

Metallic density

30wt％

Viscosity

5～20 mPa・S

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Fig. 1 Appearance of conductive ink

Fig. 2 Conductive wiring pattern made with copper nanoparticle ink printed using an ink jet printer3. Future Plans
TNSC has organized a sample production system for this product at the Yamanashi Laboratory. Moving
forward, we plan to continue efforts to introduce it to customers and provide samples to progress fullscale commercialization.
Notes:* Etching：The process of cutting metal surfaces using corrosion. An anti-corrosion treatment is applied to thesection that will be used, while the unnecessary section is eliminated using a treatment agent.

Taiyo Nippon Sanso Corporation
Tnsc.Info@tn-sanso.co.jp

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