Copper Foil Patents: Who Leads, Where the Gaps Are 2026
Rolled Annealed and Electrodeposited Copper Foil Patents: Who Files, What They Claim, Where Gaps Remain
34.7% concentration. The five leading assignees together hold 1,545 of 4,453 records in scope — a genuinely concentrated field at the top, not a fragmented one. Filings ran at 215 in 2017 and peaked at 216 in 2018, then declined toward 13 in 2026 (a partial year). The only growth figure safe to quote directly is the confirmed three-year span: 132 records in 2021 falling to 75 in 2024, a -43% move. Because publication lags filing by roughly 18 months, 2025 and 2026 figures are still filling in and should not be read as a continued decline.
- 1MITSUBISHI GAS CHEM CO INC11.6%
- 2MITSUI MINING & SMELTING CO LTD8.3%
- 3JX NIPPON MINING & METALS CORP7.2%
- 4RESONAC CORP5.0%
- 5ZEON CORP2.6%
See the full rolled annealed and electrodeposited copper foil analysis in Eureka
- The complete ranking, not just the top five
- Every IPC branch with its share of the corpus
- The most-cited records, and where claim space is still thin
Common questions on copper foil patents
Who are the leading patent holders in rolled and electrodeposited copper foil?
The ranking covers 100 companies, and it is concentrated at the top: the leading assignee holds 515 records, compared with 118 at fifth place and 69 at tenth. Together the top five hold 34.7% of all 4,453 records in scope, and the top ten hold 44.7%. The assignees are predominantly large Japanese chemicals, electronics-materials and metals groups with long-running portfolios in copper foil for printed circuit boards and laminates.
Is patent filing activity in copper foil growing or declining?
Filing volume peaked at 216 records in 2018 and has since declined; the confirmed three-year comparison shows 132 records in 2021 falling to 75 in 2024, a drop of 43%. That 2024 figure is the most recent year that can be read as complete, because publication typically lags filing by around 18 months. Years 2025 and 2026 in the raw data appear low simply because those records have not all published yet, not because filing has stopped.
What technology areas do copper foil patents mostly cover?
The dominant IPC classes are H05K (printed circuits and assemblies), touching 64.5% of the 4,453 records, and B32B (layered products and laminates), touching 44.6%. Electroplating and electroforming (C25D) appears in 22.0% of records, and polymer-chemistry classes such as C08L, C08G, C08J and C08K each sit below 19%. Because a single record can carry several IPC classes, these shares add up to more than 100%, and the pattern shows most patenting is framed around circuit and laminate integration rather than foil-production chemistry alone.
Disclaimer. This analysis is based on Patsnap Eureka data drawn from a limited snapshot of global patent records and is provided for general information and reference only. Patent data carries inherent limitations — recent filings are under-counted because of publication lag, counts may be on a record or family basis, classification and applicant-name data may contain errors or duplicates, and the underlying search query defines the scope shown — so the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing here is an exhaustive prior-art, novelty, freedom-to-operate or validity search, nor does it constitute legal, financial or professional advice, and it should not be relied upon as such. Verify independently and review with qualified patent and legal professionals before acting on it.
Method: Filing trend and technology composition. Derived from a Patsnap search on Rolled Annealed and Electrodeposited Copper Foil covering 2015–2026, data cut-off 2026-07-31. Counts reflect published records only and shift as new filings publish. Every share divides by all records in scope. Data: Patsnap Eureka. See the full landscape report.