Epoxy Resin Composite Patents: Leaders & Filing Trends 2026
- Filing has cooled since its 2019 peak. 542 families in 2019 fell to 56 by 2026 (partial year), with the 2022 midpoint of 303 confirming a declining trend rather than a temporary dip.
- The claim space concentrates in polymer chemistry, not shaping. C08L polymer compositions (12,213 records) and C08G condensation polymers (8,474) dwarf B29C shaping of plastics (1,969), showing most protected value sits in formulation, not processing.
- Momentum has stalled across the historic leaders. Recent-year filings from major Japanese and Chinese assignees have dropped to zero or near-zero, including a -100% YoY swing at Toray Industries, Inc., suggesting the field's largest incumbents are not renewing claim positions at their former rate.
Filing growth compares 2021 (355 records) with 2024 (305) — 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 14,464 records in scope (CR5), not by the ranked leaders only.
What the epoxy resin composite reinforcement patent record shows
Epoxy resin composite reinforcement covers the formulations and processes that let epoxy matrices carry fiber reinforcement — toughened epoxy chemistries, prepreg impregnation methods, and the additive packages that control resin content and cure behaviour. The dataset spans 14,464 patent families filed between 2015 and 2026 across major receiving offices, giving a broad view of where claims have been staked and where filing activity has slowed.
Because publication lags filing by roughly 18 months, the last one to two years in any trend chart will always look thinner than they eventually turn out to be. That lag matters here: the drop-off visible toward 2026 is partly an artefact of pending applications not yet published, but the multi-year decline from the 2019 peak predates that lag and reflects a genuine slowdown in new filing.
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Filing trends and technology composition
Two views of the same 14,464-family dataset: the year-by-year filing curve, and the IPC subclasses that carry the claim density.
A peak in 2019, then a steady decline
Filings rose to 542 in 2019, then eased through the 2022 midpoint of 303 down to 56 by 2026 (a partial year). The shape is consistent with a field that reached broad claim coverage of its core chemistries earlier this decade rather than one still in a growth phase.
Polymer chemistry, not shaping, carries the density
C08L (polymer compositions, 12,213 records) and C08G (condensation polymers, 8,474) lead by a wide margin over B32B (layered products, 4,382) and B29C (shaping of plastics, 1,969). H05K (printed circuits, 3,774) signals a meaningful electronics-laminate use case sitting alongside the structural-composite applications.
Shares are the percentage of the 14,464 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Epoxy Resin Composite Reinforcement with Eureka
This page is one run against one query. Ask Eureka your own question about epoxy resin composite reinforcement and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited records in this dataset
US20160002417A1 — Toughened epoxy resin/glass fiber prepreg and preparation method thereof
The present invention provides a toughened epoxy resin/glass fiber prepreg and a preparation method thereof. In a vacuum apparatus, a plasma-treated glass fiber cloth is impregnated with a toughened epoxy resin so as to form a prepreg with the reinforced fibers fully impregnated with the matrix resin, wherein the resin content is greater than or equal to 15% and less than or equal to 30%. A vacuum infusion process used in the present invention solves problems such as a complex preparation process, relatively high costs and difficult control of the resin content and the like in the current glass fiber prepregs.Filed by CHANGZHOU LOONG TOP NEW MATERIALS TECHNOLOGY CO., LTD, 2016-01-07.
View full filing details| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5648407A | Curable resin sols and fiber-reinforced composites derived therefrom | 403 |
| 2 | US5278257A | Phenol-terminated polyurethane or polyurea(urethane) with epoxy resin | 369 |
| 3 | US4778851A | Rubber-modified epoxy compounds | 311 |
| 4 | JP2009035728A | Prepreg and laminate | 297 |
| 5 | US4034013A | Impact and melt strength improvement of poly(alkylene terephthalate) | 286 |
| 6 | US20060166003A1 | Fabrication of carbon nanotube reinforced epoxy polymer composites using functionalized carbon nanotubes | 240 |
| 7 | US5405688A | Epoxy resin/aminopolysiloxane/aromatic oligomer composite | 217 |
| 8 | US20020009935A1 | Core-crush resistant fabric and prepreg for fiber reinforced composite sandwich structures | 213 |
| 9 | US6632893B2 | Composition of epoxy resin, cyanate ester, imidazole and polysulfide tougheners | 209 |
| 10 | JP2004182851A | Resin composition, prepreg, and printed wiring board therewith | 208 |
Citation counts favour older filings simply because they have had longer to accumulate references — read them as a signal of historical influence on the field's chemistry, not as a ranking of current relevance.
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Reading the filing curve and IPC composition together points to a field with settled chemistry and shifting geographic weight.
The core chemistry is largely staked
A peak-then-decline curve, with the 2022 midpoint of 303 confirming the trend rather than a blip, points to a field where the dominant toughening and impregnation approaches were claimed earlier in the period. New entrants filing broad composition claims now face a denser prior-art floor than they would have in 2018.
Formulation claims outweigh process claims
C08L and C08G together cover far more records than B29C shaping of plastics, meaning the defensible ground in this space is mostly in resin and hardener chemistry rather than in manufacturing method. Process-only filings should expect to sit on top of, not instead of, existing composition claims.
Japan leads receiving-office volume
Japan's 3,267 filings outpace China's 2,721 and the United States' 2,236, with Europe and South Korea trailing further behind. A filing strategy built only around US and EPO coverage would miss the office carrying the largest share of this dataset.
Historic leaders have gone quiet
Several of the assignees with the deepest historic filing records, including Toray Industries, Inc. and Mitsubishi Gas Chemical Company, Inc., show zero or near-zero filings in the latest year. That pattern is consistent with a maturing claim landscape rather than with any single company exiting the field.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to epoxy resin composite reinforcement, with the prior art for and against each one.
Who holds the ground, and where it is thinning
Assignee activity in this dataset skews toward a small set of Japanese, Chinese and US-based chemical and materials firms, with co-filing patterns suggesting a handful of durable academic-industry links.
One dominant co-assignee relationship
Of the 10 co-assignee pairs in the dataset, the strongest link by a clear margin pairs Dow Global Technologies LLC with University of Minnesota, followed by a related pairing with Regents of the University of Minnesota. This points to a sustained industry-academic research relationship rather than incidental co-filing.
Even active filers are pulling back
Mitsubishi Chemical Corporation still filed in the latest year, but down 80% year-on-year, one of the few assignees in the momentum data still filing at all. That makes it a bellwether: even the most persistent filer in this set is scaling back.
A broad pause, not an isolated one
Toray Industries, Inc., Mitsubishi Gas Chemical Company, Inc., Resonac Holdings Corporation, Guangdong Shengyi Technology Co., Ltd. and Dow Global Technologies LLC all show zero filings in the latest tracked year. Given publication lag, some of this reflects pending applications, but the breadth of the pause across both Japanese and Chinese assignees is notable.
| Assignee | Recent year | YoY |
|---|---|---|
| Mitsubishi Chemical Corporation | 1 | -80% |
| Toray Industries, Inc. | 0 | -100% |
| Mitsubishi Gas Chemical Company, Inc. | 0 | — |
| Resonac Holdings Corporation | 0 | — |
| Guangdong Shengyi Technology Co., Ltd. | 0 | — |
| Dow Global Technologies LLC | 0 | — |
| Sumitomo Bakelite Co., Ltd. | 0 | — |
| Matsushita Electric Works, Ltd. | 0 | — |
Where to take this analysis
The filing curve and IPC composition point to a field with settled core chemistry but open questions on process and sustainability angles.
Map claim scope against the top-cited families
Before drafting new composition claims, check them against the highest-cited records in this corpus, several of which date to the 1980s and 1990s and still anchor toughened-epoxy chemistry.
Explore citation leaders in EurekaTrack the zero-filing assignees for re-entry
Several major assignees have gone quiet in the latest tracked year. A renewed filing from any of them would be an early signal of a new technical direction worth watching closely.
Set up assignee monitoring in EurekaTest white space claims against B29C and H05K
Process-focused and electronics-laminate applications carry far fewer filings than core polymer composition, and may offer more workable claim room than filing directly against C08L.
Run a white space search in EurekaCommon questions on epoxy resin composite reinforcement patents
The dataset shows a concentrated group of Japanese and Chinese materials and chemical companies alongside at least one major US-based chemical firm with academic co-filing ties. Rather than a single dominant leader, the pattern is a moderately concentrated top group followed by a long tail of single-filing entrants. Several of the historically largest filers, including major Japanese carbon-fiber and resin producers, show sharply reduced or zero filings in the most recent tracked year, which is worth factoring into any competitive assessment.
No, the filing trend has declined since a peak of 542 families in 2019, falling to a midpoint of 303 in 2022 and 56 by 2026 (a partial year not yet fully published). Publication lag of roughly 18 months means the very latest year always understates true activity, but the multi-year decline predates that effect. The overall shape points to a field consolidating around established chemistries rather than one still expanding its claim footprint.
C08L (polymer compositions) and C08G (condensation polymers) carry by far the most records, at 12,213 and 8,474 respectively, indicating that most patent value sits in resin and hardener formulation. B32B (layered products) and B29C (shaping of plastics) cover lamination and processing claims but at much lower volume. A smaller but meaningful cluster in H05K reflects epoxy composite use in printed circuit and electronics assemblies, a use case separate from structural composites.
US20160002417A1 describes a toughened epoxy resin/glass fiber prepreg made by impregnating plasma-treated glass fiber cloth with toughened epoxy resin under vacuum, with resin content controlled between 15% and 30%. The claimed vacuum infusion process is presented as a solution to cost and resin-content control problems in earlier prepreg manufacturing methods. Anyone working on vacuum-infused prepregs with resin content in that specified range should review this filing's claim scope directly, since the abstract alone does not fix exact claim boundaries.
The IPC composition suggests process-oriented and application-specific branches are less densely claimed than core resin composition: out-of-autoclave cure cycles, recyclable or reworkable fiber-epoxy bonds, and bio-based toughening agents all sit in lower-volume classification areas relative to C08L and C08G. Given that multiple major assignees have reduced filing activity in the latest tracked year, there may also be room to revisit chemistries those companies previously dominated. Any white-space claim should still be checked against the highest-cited historical families, which remain broad anchors in toughened-epoxy chemistry.
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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.