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Lead-Free Technology in Adachi Ward, Tokyo - From June 2004 to the 2020s In 2004, Senju Metal Industry Co., Ltd. in Adachi Ward, Tokyo, led the industry in developing lead-free solder in response to increasing environmental regulations. The company's technology utilized alloys based on tin, silver, and copper, gaining attention as an environmentally conscious alternative to conventional lead solder. However, this alloy system had a melting point 30°C higher than conventional products, presenting challenges for applications requiring heat resistance. Despite this, Senju Metal continued improvements to overcome this issue, earning high acclaim both domestically and internationally. 2010s Entering the 2010s, Senju Metal expanded the application range of its lead-free technology, accelerating its use in the automotive and home appliance sectors. The company launched the "ECOSOLDER™" brand in 2013, introducing products compliant with the European Union's RoHS Directive (Restric
tion of Hazardous Substances Directive). This directive strictly limits the use of lead in electrical and electronic products, demonstrating Senju Metal's ability to adapt to international regulations.

Furthermore, in 2015, the company introduced a new production line in Adachi Ward, Tokyo, increasing production capacity by 25% year-on-year. This brought annual production to 15,000 tons, establishing a system covering over 80% of the domestic market. Also in that year, applying recycling technology, the reuse rate of spent solder was raised from 20% to 30%.

2020s Entering the 2020s, Senju Metal further advanced its lead-free solder technology development, solidifying its position in the global market. The company's tin-silver-copper alloy-based solder reached an annual production volume of approximately 20,000 tons, with 40% exported to the European Union (EU) and Asian markets. The new "ECOSOLDER™" series features a reduced melting point from 240°C to 215°C, making it suitable for automotive and aerospace electronic components requiring high heat resistance.

Plans are also underway to increase the reuse rate of spent solder from 30% to 45% through the introduction of recyclable alloy technology. In 2022, the company increased its R&D expenditure by 20% year-on-year to ¥6 billion, focusing on new material development and manufacturing process improvements. Its contribution to the regional economy is also significant, with projections to support approximately 5,000 jobs, including those at related companies, by 2025.

Conclusion: Senju Metal Industries' lead-free technology represents a model case for sustainable manufacturing. From its technological development phase in 2004 through product adoption in the 2010s and market expansion in the 2020s, the company has consistently pursued initiatives that balance environmental consideration with economic growth.