Development of Conductive Paste for High accuracy Vital Sensing Electrodes

June 6, 2022

Tokyo, Japan –June 6, Sumitomo Bakelite Co., Ltd. (Headquarters: Shinagawa-ku, Tokyo, President: Kazuhiko Fujiwara) has developed a silver paste based on DuraQ®, a highly tear-resistant silicone rubber. Joint development with Mitsufuji Co., Ltd. (Headquarters: Seika-cho, Soraku-gun, Kyoto Prefecture, President: Ayumu Mitera) has demonstrated that high-precision vital sensing with extremely low body motion noise is possible by combining a conductive cloth made of silver-plated yarn with our company silver paste.

Development Background

In recent years, wearable devices equipped with vital data measurement functions have appeared, which are used daily in response to changing consumer health awareness and demand. However, many wearable devices have been susceptible to noise caused by body movement, therefore it has been said that it is difficult to obtain accurate vital data.
We have been developing conductive silver paste based on our original silicone rubber with high tear resistance for stretch wiring. This silver paste, which is biocompatible and can draw stretchable wiring. This stretchable circuit is wash-resistant and is attracting attention for use in wearable vital sensing. It also has good conductivity and a specific resistance of 10-4 Ω · cm.
With the cooperation of Mitsufuji Co., Ltd., we have demonstrated that the electrocardiographic waveform with extremely low noise, which could not be obtained with conventional dry electrodes, can be measured even during body movement (for example, while walking) by combining it with a conductive cloth made of silver-plated yarn.

About Developed Products

High Tear-Resistant Silicone Rubber DuraQ® uses our company's original formulation technology to combine the properties of ordinary silicone rubber with a low hardness (30 A), average tear strength of 39.1 N/mm, and the world's highest level of extremely high tear strength.

Tough, excellent in abrasion resistance, and compatible with a wide range of types with hardness from 30 A to 70 A, with biocompatibility. The developed product is a paste made from this silicone rubber as a base resin.
The plain type is an insulating paste, and the one mixed with conductive fine particles such as silver powder is a conductive paste.

Application as Wearable Electrocardiograph Electrode

By using electrodes (hereinafter referred to as "new electrodes") made by combining our company silver paste with conductive fabric made from silver plated yarn, a product of Mitsufuji Co., Ltd., for example, as a wearable electrocardiograph, we were able to measure electrocardiogram shapes with extremely low body motion noise.
Generally, to measure a valid electrocardiogram (raw, unprocessed data), the person must be quiet and immobile. For example, electrocardiography during a 5-minute walk showed only 1.6% noise with the new electrodes. Also, a high success rate can be obtained during sports.

Actual measurement data during walking (noise 1.6%)
(provided by Mitsufuji Co., Ltd.)

In this way, electrocardiography can be performed as raw data that is not complemented even when the body is moving. This enables continuous electrocardiography during daily life, and is expected to be used in medical applications. The new electrode has also been demonstrated to be resistant to linen washing.

Potential application field

  • Various high-temperature environmental work such as transportation and construction sites
  • Work involving stress, such as pilots, drivers, and cabin attendants
  • Sports
  • Medical and nursing care profession
  • Automobile
  • IoT, Metaverse

Mitsufuji Co., Ltd.

Head Office :   13F Keihanna Plaza, 7–1 Chome Hikaridai, Seika, Soraku District, Kyoto 〒619-0237
Main Businesses :   Development, manufacture and sale of silver-metalized conductive fiber AGposs® and wearable IoT hamon® products

  • The above measurements, figures and expressions are representative values or examples and are not guaranteed.

Related Information

For inquiries on this product

Sumitomo Bakelite Co., Ltd., Smart Community Marketing & Developing Division