Polyimide Composite Patents: Who Leads, Filing Trends 2026
- Filings peaked in 2018 and have since flattened. the curve fell from 30 in 2018 to a 2022 midpoint of 18, with no sign of a new growth phase.
- China dominates the filing map. 291 of the tracked receiving-office filings originate there, versus 35-39 each for Japan, Europe and the US.
- Collaboration is rare. only four co-assignee pairings exist across the entire 438-family dataset, and most are single instances.
Filing growth compares 2021 (25 records) with 2024 (29) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 438 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Polyimide composite reinforcement covers fiber-reinforced and filler-loaded polyimide matrix systems — the additive packages, condensation chemistry, and processing methods used to turn a heat-resistant polyimide resin into a structural composite. This landscape draws on 438 patent families published between 2015 and 2026, filed against IPC classes spanning polymer additives (C08K), polymer compositions (C08L), processing (C08J), condensation chemistry (C08G) and composite shaping (B29C).
Filing activity in this space peaked in 2018 and has not returned to that level since, and China accounts for the majority of receiving-office filings tracked here. The technology composition is heavily weighted toward additive and formulation chemistry rather than fabrication method, which shapes where new claims are likely to collide with prior art.
Filing trends and technology composition
The filing curve and the IPC spread together show where claim density has built up and where it has thinned out since polyimide composite filings peaked in the late 2010s.
A peak-and-plateau filing curve
Filings rose to a peak of 30 in 2018, sat near a midpoint of 18 by 2022, and have not returned to peak levels since — a flat-to-declining trend rather than a growth curve. The final year or two is necessarily undercounted, since publication typically lags filing by around 18 months.
Additives and processing dominate the IPC spread
C08K (additives) and C08L (polymer compositions) each cover roughly three-quarters of the dataset, with C08J (processing) close behind — a heavy concentration on formulation and processing claims. B32B (laminates), B29B (plastics preparation) and C09K (miscellaneous materials) trail well behind, marking the thinner branches of the IPC spread.
Shares are the percentage of the 438 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Polyimide Composite Reinforcement with Eureka
This page is one run against one query. Ask Eureka your own question about polyimide composite reinforcement and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative filing and the most-cited records
EP0776924A2 — Mitsubishi Jukogyo's addition-cured polyimide prepreg system
An addition type polyimide resin raw material composition having high heat resistance and high corrosion resistance comprising a tetracarboxylic anhydride and/or tetracarboxylic diester compound, diamine compound and exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride and/or exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic monoester compound; a composition containing a prepreg; a fiber-reinforced polyimide composite prepreg, coating material and paint using them; and a curing method thereof.Filed by Mitsubishi Jukogyo Kabushiki Kaisha, published 1997-06-04.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20120065283A1 | Reinforced thermoplastic articles, compositions for the manufacture of the articles, methods of manufacture, … | 93 |
| 2 | US5549394A | Bearing arrangement having a polyimide graphite-fiber reinforced composite embedded therein | 78 |
| 3 | US4759987A | Polyimide powder and process for producing the same | 61 |
| 4 | US5664890A | Bearing arrangement having a polyimide graphite-fiber reinforced composite embedded therein | 52 |
| 5 | CN108276576A | 碳纳米管和石墨烯共价连接协同增强聚酰亚胺复合材料及其制备方法 | 47 |
| 6 | US4244853A | Composition and method for making polyimide resin-reinforced fabric | 43 |
| 7 | US6036900A | Resin transfer imidization of polyimide matrix composites | 36 |
| 8 | CN1676548A | 一种短纤维增强聚酰亚胺复合材料及制备方法和用途 | 35 |
| 9 | US5043419A | Process for preparing a polyimide and a composite material containing the same | 33 |
| 10 | CN102942668A | 一种填充功能填料的聚酰亚胺复合泡沫材料制备方法 | 31 |
Citation counts favour older records simply for having been available longer; treat this as a map of influence within the corpus, not a ranking of current commercial importance.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. Each row carries its publication number; clicking a row searches Eureka by that number.
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Four figures from this dataset matter more than the raw count: they show where claim density has settled, and where it has not.
A plateaued field, not a growing one
The filing curve rose to 30 in 2018, sat at 18 by the 2022 midpoint, and has not returned to peak levels since. This is a mature filing base rather than an emerging one, though the final year or two is always understated due to publication lag.
Additive chemistry is the densest claim zone
C08K and C08L together cover the large majority of records, meaning most of the field's claim space is already staked out in filler and formulation chemistry rather than in processing or shaping method.
Filing activity is concentrated in one jurisdiction
China's receiving-office count is roughly eight times any single Western or Japanese office in this dataset, which changes where freedom-to-operate risk actually concentrates for a global filer.
Filers mostly work alone
Only four co-assignee pairs appear in the dataset, and the strongest is a repeated aerospace-institute pairing rather than a cross-sector collaboration, suggesting joint development is the exception, not the norm, in this field.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to polyimide composite reinforcement, with the prior art for and against each one.
Who is filing, and where the field is open
Filing activity is spread across aerospace research institutes, Japanese and US materials companies, and Chinese universities, with little cross-assignee collaboration and no assignee showing filing growth in the most recent tracked year.
The only repeat collaboration in the dataset
The strongest co-assignee relationship in this landscape is a Chinese aerospace materials institute paired with a rocket-technology research academy, filing together across eight families — the one clear pattern of sustained joint development in an otherwise fragmented field.
Established chemical companies have gone quiet
Assignees with historically strong positions, including established Japanese and US materials companies, show no filings in the most recent tracked year, which is consistent with the dataset's overall plateau rather than a company-specific pullback.
Chinese universities and manufacturers fill the mid-tier
Chinese university and enterprise-group assignees appear steadily through the dataset's peak years but, like the rest of the field, show no filings in the latest tracked year — a pattern shared across nearly every named assignee here.
| Assignee | Recent year | YoY |
|---|---|---|
| Mitsui Chemicals, Inc. | 0 | — |
| Aerospace Research Institute of Materials & Processing Technology | 0 | -100% |
| E.I. du Pont de Nemours and Company (USA) | 0 | — |
| Heilongjiang Xinda Enterprise Group Co., Ltd. | 0 | — |
| Aerospace Research Institute of Materials & Processing Technology | 0 | — |
| Tongji University | 0 | — |
| China Academy of Launch Vehicle Technology | 0 | — |
| Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences | 0 | -100% |
Where to take this analysis
The dataset points to a mature, formulation-heavy field with concentrated filing geography and thin collaboration. The next steps depend on whether you are clearing a formulation or scouting open ground.
Run a freedom-to-operate check on additive chemistry
With C08K and C08L covering the large majority of families, any new filler or coupling-agent claim should be checked against this dense core before drafting.
Search the additive claim space in EurekaScope the under-claimed branches
B29B preparation steps and C09K specialty-additive packages carry a fraction of the filings the core chemistry does, making them a faster path to distinct claim territory.
Explore white space in EurekaTrack assignee momentum before it shifts
No leading assignee shows filings in the latest tracked year, so a new entrant filing now would be moving into a field with unusually low active competition.
Monitor assignee activity in EurekaCommon questions about polyimide composite reinforcement patents
The most-cited records in this dataset are US20120065283A1 on reinforced thermoplastic articles and the related pair US5549394A and US5664890A on polyimide graphite-fiber composite bearing arrangements. These are influence signals within the searched corpus, not current market-share indicators, since older patents accumulate citations simply by being available longer. A newer, less-cited filing can still be commercially important if it targets a route the older patents do not cover.
No — filings peaked at 30 in 2018 and had fallen to a midpoint of 18 by 2022, with the trend flat to declining through the most recent tracked years. The final year or two in any such dataset is understated because publication lags filing by roughly 18 months, so recent activity is not fully visible yet. Even accounting for that lag, the shape of the curve points to a mature filing base rather than an accelerating one.
C08K (use of additives in polymers) and C08L (polymer compositions) carry the largest share of records, both close to three-quarters of the dataset, followed by C08J for processing and solution work. B29C covers shaping of the finished composite, while B32B, B29B and C09K cover laminate structure, plastics preparation and specialty materials respectively at much lower density. That spread shows the field is defined more by formulation and additive chemistry than by any single fabrication method.
China accounts for the largest share of receiving-office filings in this dataset at 291, well ahead of Japan, Europe and the United States, which each sit in the 35-39 range, with South Korea and WIPO/PCT filings trailing further behind. That concentration reflects where composite manufacturing and materials R&D activity is currently filed, though it does not by itself indicate where the underlying research originated. A filer targeting global freedom-to-operate should still check coverage in Japan, Europe and the US given their comparable filing volumes.
EP0776924A2, filed by Mitsubishi Jukogyo, claims an addition-type polyimide resin composition built on a specific tetracarboxylic anhydride/diester, a diamine, and an exo-epoxy tetrahydrophthalic crosslinker, along with the resulting prepreg, coating and paint. It blocks that particular resin chemistry and its direct downstream products, not the wider space of fiber-reinforced polyimide composites. Work using a different crosslinking chemistry or focused on the curing process rather than the raw resin composition generally falls outside its claim scope.
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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.