Polyimide Testing Patents: Leaders, Trends & White Space 2026
- Filing has cooled since 2021. the peak year for this search (12 families) has given way to a flatter, declining trend through the most recent full year — consistent with a field settling into incremental claims rather than fresh invention.
- C08L dominates the composition mix. 181 of 200 records sit in polymer-composition claims, with condensation-polymer chemistry (C08G, 128 records) as the dominant secondary class — testing and inspection claims are filed on top of material claims far more often than as standalone method patents.
- The United States leads filing offices. 64 of the tracked records were filed at the USPTO, ahead of the EPO (55) and Japan (29) — a signal for where enforcement risk and prior art density concentrate first.
What this landscape covers
This review tracks 200 patent families filed between 2015 and 2026 that combine polyimide or polyimide-film claims with thermal analysis, dielectric testing, mechanical testing or film-inspection language, indexed against C08L79/08, G01N25 and G01R31. It is a narrow cut of a much larger polyimide literature: most records here claim a material or film composition and fold in a test or inspection method as a dependent claim or example, rather than claiming a standalone measurement apparatus.
Because publication lags filing by roughly 18 months, the most recent year in the trend chart is understated and should not be read as a real drop-off. The picture that does hold up across the full window is a mid-2010s build-up, a 2021 peak, and a flatter tail since — more consistent with consolidation around known test protocols than with an open, fast-growing field.
Filing trend and technology composition
Two views of the same 200-family dataset: how filing volume has moved year over year, and how the underlying IPC classes describe what is actually being claimed.
A 2021 peak followed by a flatter tail
Filings ran from 8 in 2017 up to a peak of 12 in 2021, sat at 9 by the 2022 midpoint, and have declined since — a pattern that reads as maturing claim space rather than an emerging one, though the final one to two years are still filling in as publications catch up.
Composition claims carry the testing language
C08L (polymer compositions) appears in 181 of 200 records and C08G (condensation polymers) in 128, meaning most testing and inspection claims are attached to a specific polyimide formulation rather than filed as a generic method. Additive use (C08K, 66), processing and solution claims (C08J, 50) and layered-product claims (B32B, 24) round out the picture; printed-circuit applications (H05K, 16) are the smallest but most application-specific slice.
Shares are the percentage of the 200 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Polyimide Testing and Inspection with Eureka
This page is one run against one query. Ask Eureka your own question about polyimide testing and inspection and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative filing and most-cited prior art
US20190134963A1 — Polyimide film layered body (Toyobo Co., Ltd., 2019-05-09)
A laminate mainly made of polyimide with low thermal expansion, high mechanical strength, and high heat resistance, and a method for manufacturing the same are provided. A surface of a polyimide film is activated and then treated by a silane coupling agent. Subsequently, the obtained silane coupling agent-treated polyimide films are superimposed, and pressure and heat are applied to the superimposed polyimide films so as to manufacture a polyimide film laminate.Abstract truncated at source; full claim language should be checked against the granted specification before relying on it for freedom-to-operate work.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6001507A | Non-aqueous electrolyte secondary battery | 122 |
| 2 | US20020016438A1 | Polyimide silicone resin, process for its production, and polyimide silicone resin composition | 51 |
| 3 | US9745198B2 | Porous nanostructured polyimide networks and methods of manufacture | 40 |
| 4 | JP1990251564A | Fluorine-containing polyimide composition and production thereof | 37 |
| 5 | US6141093A | Method and apparatus for locating power plane shorts using polarized light microscopy | 34 |
| 6 | JP1992288344A | Protective film and member having protective layer | 34 |
| 7 | US20050054753A1 | Sealing composition and seals made by using the same | 27 |
| 8 | US5059273A | Process for preparing polyimide composites | 27 |
| 9 | US6734276B2 | Polyimide and circuit substrate comprising the same | 22 |
| 10 | US6114472A | Thermoplastic resin composition containing amorphous polyimide | 22 |
Citation counts are measured within this searched corpus and favour older filings; treat them as a signal of past influence on later filers, not of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three read-throughs from the trend and classification data that matter more than the raw counts.
The field has passed its filing peak
Volume rose steadily from 2017 to a high of 12 families in 2021, then eased to 9 by 2022 and has trended down since. That is not evidence the underlying material science is finished — it more often means the core test protocols (thermal cycling, dielectric breakdown, mechanical pull) are now well-precedented and later filers are claiming narrower variations.
Testing claims ride on composition claims
Nine in ten records in this search carry a C08L polymer-composition class, and nearly two-thirds also carry C08G condensation-polymer chemistry. A standalone inspection-method patent, unattached to a specific polyimide formulation, is the exception here rather than the rule.
US and Europe carry the enforcement risk
The United States and the European Patent Office between them account for well over half the tracked filings, with Japan a distinct third. WIPO/PCT filings (17) suggest a modest but real appetite for multi-jurisdiction protection, while China (8) and Canada (10) remain comparatively thin.
Collaboration is rare and legacy-driven
Only two co-assignee pairings surface in this dataset, the stronger being a historical link between two Mitsubishi chemical entities across six shared families. Cross-company joint filing is not a meaningful feature of this space; most activity is single-assignee.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to polyimide testing and inspection, with the prior art for and against each one.
Who is active, and where momentum has stalled
Assignee activity in this dataset skews toward established polyimide and specialty-chemical manufacturers, several of which show no filings in the most recent tracked year.
Several established filers went quiet
Assignees including DIC, Mitsubishi Chemical, Evonik Operations, SABIC and Noritake all show zero filings in the latest tracked year in this search, with one entity down 100% year-over-year. That is consistent with the broader post-2021 slowdown rather than any single company exiting the space.
Legacy corporate structures still show in the record
The strongest co-assignee pairing in this dataset links Mitsubishi Chemical and Mitsubishi Petrochemical across six shared families, reflecting a historical corporate relationship rather than an active joint-development programme.
Specialty-chemical manufacturers, not equipment makers, lead filing
Most of the highest-activity assignees in this space are polyimide resin and film producers rather than test-equipment vendors, reinforcing that inspection and testing claims here are largely defensive extensions of material patents rather than a separate instrumentation business.
| Assignee | Recent year | YoY |
|---|---|---|
| DIC Corporation | 0 | — |
| Aspen Aerogels, Inc. | 0 | -100% |
| Mitsubishi Chemical Corporation | 0 | — |
| Evonik Operations GmbH | 0 | — |
| SABIC Global Technologies B.V. | 0 | — |
| Noritake Co., Limited | 0 | — |
| E.I. du Pont de Nemours and Company | 0 | — |
| Teijin Limited | 0 | — |
Where to take this analysis
The dataset points to a field with occupied composition-claim space but thinner standalone method claims. Two directions follow from that.
Check freedom-to-operate before filing a composition claim
With 181 of 200 records already classed under C08L polymer compositions, a new polyimide formulation claim is more likely to run into dense prior art than a narrowly drafted test-method claim would.
Run a freedom-to-operate search in EurekaModel the standalone test-method gap
The scarcity of pure inspection or measurement claims, separate from a specific polyimide formulation, suggests room for method-only filings that are formulation-agnostic.
Explore white space with EurekaCommon questions about polyimide testing patents
This search identifies 200 patent families filed between 2015 and 2026 that combine polyimide or polyimide-film claims with thermal, dielectric or mechanical testing language, or film-inspection methods. That figure reflects the specific IPC and keyword search used here (C08L79/08, G01N25, G01R31 among others) and is narrower than the total polyimide patent literature, which is much larger. Broadening or narrowing the keyword set will change the count, so treat 200 as a defined-scope figure rather than an industry total.
Filings in this dataset rose from 8 in 2017 to a peak of 12 in 2021, then eased toward 9 by 2022 and have trended down since. That pattern is more consistent with core test protocols — thermal cycling, dielectric breakdown, mechanical pull testing — becoming well established and precedented than with the underlying material science losing relevance. It's also worth noting publication lag: filings from the last one to two years are still being published, so the most recent years in any chart understate true activity.
The dataset shows activity concentrated among established polyimide and specialty-chemical manufacturers rather than test-equipment vendors, with several long-standing filers, including DIC, Mitsubishi Chemical, Evonik Operations and SABIC, showing no filings in the most recent tracked year. This is consistent with the broader post-2021 slowdown across the field rather than any single company exiting. Full current assignee rankings are rendered in the table on this page rather than summarised here, since a hand-picked list would go stale as the dataset updates.
The clearest gap is standalone test-method claims: 181 of 200 records in this search carry a C08L polymer-composition class, meaning most testing and inspection claims are filed as dependent claims or examples attached to a specific polyimide formulation rather than as formulation-agnostic method patents. Smaller IPC classes in this dataset, such as printed-circuit-integrated inspection (H05K, 16 records) and layered-product testing (B32B, 24 records), also show comparatively thin claim density. A first claim drafted around a measurement method independent of any particular resin chemistry is one route into that gap.
In this dataset the United States leads with 64 filings, followed by the European Patent Office at 55 and Japan at 29, with WIPO/PCT, Canada and China trailing further behind. For freedom-to-operate or prior-art work aimed at US or European commercialisation, those two offices carry the bulk of the enforceable prior art in this space. China's comparatively low count (8) may reflect either lighter actual filing activity there or gaps in how this particular search string surfaces Chinese-language filings, so a supplementary China-specific search is worth running before concluding the market is open.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.