On Dec. 23, 2023, South Korea became a 'super-aged society.' The proportion of the population aged 65 and over (10,244,550) among South Korean residents surpassed 20%. The United Nations (UN) classifies a society as aged when the population aged 65 and over accounts for more than 7% of the total, an aging society when it surpasses 14%, and a super-aged society when it exceeds 20%. In this regard, ChosunBiz introduces overseas businesses focused on senior citizens and the societal problems arising from super-aged societies, centered around Japan, which entered a super-aged society 19 years earlier in 2004. [Editor’s note]
Are diapers only for babies? No. Adults, especially women suffering from urinary incontinence and the elderly who cannot go to the bathroom on their own due to illness, also rely on diapers. The issue is when to change the diapers. Parents raising babies face the challenge of constantly checking their child's diaper before they can express themselves. However, the situation changes when older adults use diapers. It is not easy for caregivers to frequently check the diapers. However, if a person wears a diaper for an extended period after using the restroom, it can lead to secondary diseases such as urinary tract infections, making timely diaper changes essential.
Perhaps for this reason, a prototype of a smart diaper unveiled by Japanese semiconductor company Asahi Kasei at CES 2025, the world’s largest IT and electronics fair held in Las Vegas in January, caught attention. The smart diaper developed by Asahi Kasei alerts caregivers when a change is needed, similar to existing smart diapers. Up to this point, it is no different from existing smart diapers launched by domestic startups. What stands out is that it does not require a battery. The smart diaper designed by Asahi Kasei contains electrodes that generate voltage from the patient's urine. This perplexing yet intriguing concept was discussed with Asahi Kasei Group, and Yagi Satoshi, head of the solution development group at Asahi Kasei Electronics, provided answers in writing.
As a reference, the size of the adult diaper market in Japan was $2.51 billion in 2023, with expectations to grow to $4.3 billion by 2032. This translates to an average annual growth rate of 6.3%. The increasing occurrence of urinary incontinence and the aging population have led to significant growth in Japan’s adult diaper market.
First, please introduce the Asahi Kasei Group.
“Asahi Kasei Group is a comprehensive chemical company founded in 1922. Its mission is to 'provide the best daily necessities at affordable prices to help people enjoy a better life.' It achieved notable successes in synthetic chemicals and chemical fibers, including being the first in Japan to synthesize ammonia using the Haber process with hydrogen generated from water electrolysis. Since then, the company has diversified its business, currently operating in three areas: 'Materials' for fiber, chemicals, and electronic components; 'Dwellings' for housing and building materials; and 'Healthcare' for pharmaceuticals and medical services. In Korea, it focuses on chemical, fiber, electronic components, and electronic materials businesses.”
Which team within Asahi Kasei Group developed the adult smart diaper?
“The concept was presented by Asahi Kasei Electronics, which operates in the electronic components business within Asahi Kasei Group.”
What inspired the development of the adult diaper? Was it because the adult diaper market is expected to grow?
“For several years, we have been developing non-contact stethoscopes and thermometers that can detect a person's condition with very little power. During this time, we thought about applying the technology used in sensors for detecting leaks in building plumbing to urine, leading us to create a diaper. In the course of researching the uses of diapers, we discovered that caregivers in medical settings face the chore of visually confirming and changing diapers or recording after changing them. The smart diaper eliminates the hassle of checking the diaper visually and automates the record-keeping process, increasing efficiency. Furthermore, it ensures that the dignity of the individuals receiving care is not compromised.”
I understand that the electrodes installed inside the diaper detect the patient's urine to generate voltage. Could you easily explain how it works without batteries?
“Think of a lemon battery from a grade school science experiment. In the diaper, the electrolyte is not lemon juice but urine. When there is moisture (the electrolyte) between the anode and cathode, electricity is generated. In this way, the power generated using urine in the smart diaper can be used to send alerts via Bluetooth to smart devices like smartphones, indicating when a diaper change is needed. Of course, the power generation is modest when using liquids such as urine or tap water. However, our unique technology enables us to generate enough power to operate electronic devices.”
Although the power generated from urine is low, you mentioned that Asahi Kasei's technology overcomes this. Please explain.
“We do not increase the absolute amount of power generated from urine. However, the smart diaper is equipped with Asahi Kasei’s ultra-low power boost converter, the AP4470L. This boost converter can amplify the 300 mV voltage produced by the moisture in urine to about 3V, even in conditions where urine may not effectively act as an electrolyte. Therefore, even the small amount of power generated from urine can operate sensors and transmit signals for diaper changes via Bluetooth.”
What distinguishes your smart diaper from those released by other companies?
“Other companies' adult diapers contain built-in batteries like button cells. However, our smart diaper generates power from urine, so it does not contain batteries. Therefore, it is superior in terms of safety against accidental ingestion of button batteries. Additionally, since there is no need to replace batteries, it also excels in waterproof properties and durability.”
Although the smart diaper created by Asahi Kasei Group does not have a built-in battery, electrodes that serve as anodes and cathodes are necessary. What is the weight of these electrodes?
“The smart diaper contains electrodes (conductive materials) serving as anodes and cathodes. A thin film performing the role of an electrode is attached to the diaper in the prototype. It uses very lightweight materials like aluminum foil.”
Are there any design features unique to Asahi Kasei diapers among adult diapers sold in Korea, which also includes gray ones?
“Asahi Kasei’s smart diaper has a design identical to that of ordinary diapers. The difference is that it contains electrodes inside the diaper and has an exchangeable electronic device.”
Is the target audience for the smart diaper prototype patients admitted to hospitals?
“Those who need diapers are not limited to patients but include individuals with urinary incontinence, as well as people who work outside for extended periods. Initially, we are considering targeting caregivers at home.”
When is the commercialization of the smart diaper expected?
“While we hope to showcase the mass-produced version to the market as soon as possible, the release date is yet to be determined. The specific timeline for commercialization will be decided through consultations with collaborative partners and diaper manufacturers.”
What price are you expecting for the sale?
“We cannot respond yet as discussions with diaper manufacturers are still ongoing. However, we believe the market will not accept the product if the price significantly differs from existing diapers available in the market. We aim to strike a compromise and present an appropriate price.”
Are there plans to sell smart diapers in Korea as well?
“Demand is expected in advanced countries, including Korea, where aging is progressing. However, regarding the sale of smart diapers, we will need to discuss further with diaper manufacturers.”