Epoxy Resin Additives Patents: Leaders, Trends & White Space 2026
- Filing has cooled since a 2017 peak. 485 families filed in 2017 against 59 so far in the most recent (partial) year, with 2022's 353 marking the last stable midpoint before the decline set in.
- Japan dominates the filing map. 4,758 records route through the Japanese office, nearly double the United States (2,623) and well ahead of China (2,128) and Europe (2,128), pointing to where enforcement and prior art risk concentrate.
- Collaboration is rare and narrow. Only 10 co-assignee pairs appear across 14,813 families, and the strongest link — 42 shared filings — sits between two Japanese conglomerates, not across borders or sectors.
Filing growth compares 2021 (341 records) with 2024 (285) — 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 14,813 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This dataset tracks patent families whose title or abstract references epoxy resin, epoxy, or epoxy formulation, combined with claim or description language around toughening agents, flame retardant fillers, nanofillers, or curing accelerators, and classified under C08K3, C08K5, or C08L63. It captures the additive and filler layer of epoxy chemistry rather than the base resin synthesis itself — the compounds and particulates that determine impact resistance, flame behaviour, thermal conductivity and cure kinetics in finished formulations.
The coverage window runs from 2015 through the third quarter of 2026, with 14,813 published families in total. Because publication typically lags filing by around 18 months, the last one to two years in any trend line will understate actual filing activity — the 2026 figure in particular should be read as a floor, not a ceiling.
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Filing trend and technology composition
Two views of the same corpus: how filing volume has moved year over year, and which IPC subclasses the underlying families actually sit in.
A decade past its peak
Filings ran at 485 in 2017, held near a midpoint of 353 by 2022, and have fallen to 59 in the most recent partial year. Read alongside the 18-month publication lag, the honest interpretation is a market that has plateaued and is now trending down rather than one still accelerating.
Concentrated in polymer composition classes, with electronics as a secondary pull
C08L (polymer compositions) and C08G (condensation polymers) cover the bulk of the corpus, with C08K (additive use) close behind — consistent with a dataset built around formulation and filler chemistry. The presence of H01L (semiconductor devices) and H05K (printed circuits) at meaningful volume signals that a large share of this filing activity is driven by electronics encapsulation and underfill applications rather than structural composites alone.
Shares are the percentage of the 14,813 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Epoxy Resin Additives and Fillers with Eureka
This page is one run against one query. Ask Eureka your own question about epoxy resin additives and fillers and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited prior art and a representative filing
Curing accelerator for deep-ultraviolet-transmitting epoxy resin, deep-ultraviolet-transmitting epoxy resin composition, and deep-ultraviolet-transmitting epoxy resin cured product
The filing discloses a curing accelerator built from a tetraalkylphosphonium dialkyl phosphate, intended to produce deep-UV-transmitting epoxy resin cured products with high heat resistance. It targets a narrow but technically demanding niche: optical and UV-exposed applications where conventional curing chemistry compromises light transmission or thermal stability.Filed by Nippon Chemical Industrial Co., Ltd., published 2009-05-07.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5278257A | Phenol-terminated polyurethane or polyurea(urethane) with epoxy resin | 369 |
| 2 | WO2007025007A1 | Epoxy compositions having improved impact resistance | 275 |
| 3 | EP1632533A1 | Process for producing modified epoxy resin | 261 |
| 4 | US20050070634A1 | Process for applying a streamable epoxy adhesive | 255 |
| 5 | US6573309B1 | Heat-curable, thermally expandable moulded part | 247 |
| 6 | US7037958B1 | Epoxy coating | 221 |
| 7 | US20070027233A1 | Process for producing modified epoxy resin | 219 |
| 8 | US5405688A | Epoxy resin/aminopolysiloxane/aromatic oligomer composite | 217 |
| 9 | WO2006061249A1 | Aqueous binder for mineral fibers | 213 |
| 10 | US6572971B2 | Structural modified epoxy adhesive compositions | 212 |
Citation counts reflect influence within this searched corpus and skew toward older filings — treat them as a map of foundational art, not of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers say about this field
Three patterns stand out once filing volume, geography and citation data are read together.
A field past its filing peak
Volume peaked in 2017 and has declined through the 2022 midpoint of 353 down to 59 in the most recent partial year. Even allowing for the 18-month publication lag, the trajectory points to a maturing space where core additive chemistries are largely staked out.
Japan is the office of record
Japan accounts for nearly twice the volume of the next-largest office (United States, 2,623), with China and Europe close behind. Freedom-to-operate work that skips a Japanese search is working from an incomplete picture.
Filing is largely solitary
Only 10 co-assignee pairs exist across 14,813 families, and the strongest — 42 shared filings between two Japanese firms — is still a domestic, single-sector pairing. Cross-licensing or joint-development filings are the exception, not the norm.
Electronics is a real secondary driver
Semiconductor devices (H01L) and printed circuits (H05K) together account for a substantial share of the corpus alongside core polymer classes, indicating that encapsulation and underfill use cases shape a meaningful portion of additive innovation, not just structural composites.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to epoxy resin additives and fillers, with the prior art for and against each one.
Who is filing, and where activity has stalled
Assignee-level filing has gone quiet across the board in the most recent year, even among historically active filers — a pattern worth checking against each firm's broader portfolio before reading too much into any single year.
Even the most active recent filer is slowing
Shin-Etsu Chemical shows just 1 filing in the latest year against an 88% year-on-year decline — the only assignee in the momentum set with any recent activity at all. Every other tracked assignee, including Sumitomo Bakelite Co., Ltd. (Sumitomo Bakelite) and Resonac Holdings Corporation (Resonac), shows zero filings in the latest year.
Read the latest year with caution
A near-universal drop to zero in the most recent year is consistent with the roughly 18-month gap between filing and publication rather than an actual halt in R&D. The safer read is that these firms' most recent work simply has not published yet.
The strongest tie is domestic and narrow
The single strongest co-assignee relationship in the dataset links two Japanese firms — Resonac and Hitachi — at 42 shared filings, with the next two pairs (Sumitomo Bakelite with NEC, and Sumitomo Bakelite with Sumitomo Dielec) both below 25. Cross-border joint filing is essentially absent from the top tier.
| Assignee | Recent year | YoY |
|---|---|---|
| Shin-Etsu Chemical Co., Ltd. | 1 | -88% |
| Sumitomo Bakelite Co., Ltd. | 0 | — |
| Resonac Holdings Corporation | 0 | — |
| Nitto Denko Corporation | 0 | — |
| Matsushita Electric Works, Ltd. | 0 | — |
| Toray Industries, Inc. | 0 | — |
| Dow Global Technologies LLC | 0 | — |
| Mitsubishi Gas Chemical Company, Inc. | 0 | — |
Where to take this analysis
The trends above raise questions that a landscape summary can point to but not fully answer.
Check freedom-to-operate against the Japanese-office cluster
With Japan accounting for the largest single share of receiving-office volume, any new formulation work in toughening agents or curing accelerators should be checked against that cluster first, not treated as a secondary market.
Run a claim-level FTO check in EurekaTest the under-claimed branches for real white space
Thin filing density in areas like phosphonium-based latent catalysts or low-outgassing underfill fillers may reflect genuine white space or simply narrower commercial demand — the difference matters before committing R&D spend.
Explore white space mapping in EurekaWatch for the publication-lag rebound
The near-universal drop to zero in the latest year across major assignees is likely a lag artifact rather than a real slowdown. Revisiting this trend in 12–18 months will show whether filing has actually stalled or simply not yet published.
Track assignee filing activity in EurekaCommon questions about epoxy resin additive patents
In this landscape, the additive layer covers toughening agents that improve impact resistance, flame retardant fillers, nanofillers used for thermal or mechanical reinforcement, and curing accelerators that control cure kinetics. These are claimed separately from the base epoxy resin synthesis itself, usually under IPC classes covering additive use in polymers (C08K) and specific polymer compositions (C08L). A workable claim typically ties a specific compound class or particle chemistry to a measurable performance outcome, such as impact strength, flame rating, or cure temperature.
Filing volume peaked at 485 in 2017 and has fallen steadily to 59 in the latest partial year, with 2022 marking a midpoint of 353. This pattern is consistent with a maturing field where core toughening-agent and flame-retardant-filler chemistries are already well claimed, pushing new filings toward narrower niches. It is also worth discounting the most recent one to two years for publication lag, since filings made recently may not yet be visible in the data.
Japan is the largest receiving office in this dataset by a wide margin, with roughly 4,758 records compared to 2,623 in the United States and similar volumes in China and Europe. Any freedom-to-operate or prior art search that omits Japanese-language filings is working from an incomplete picture of this field. That said, meaningful volume also exists in the US, China, and Europe, so a single-office search is rarely sufficient on its own.
Independent filing dominates: only 10 co-assignee pairs appear across 14,813 patent families in this dataset. The strongest pairing links two Japanese firms with 42 shared filings, and the next strongest pairs sit below 25. Cross-border or cross-sector joint filing is rare, suggesting that most innovation in toughening agents, fillers and curing accelerators happens inside single organisations rather than through formal co-development partnerships.
Filing density is comparatively thin in narrower technical branches such as deep-UV-stable curing accelerators, phosphonium-based latent catalysts, nanofiller dispersion methods for thermal interface applications, and low-outgassing fillers for underfill use. These pockets sit adjacent to the dense core of general toughening and flame-retardant claims, where prior art is thick. Thin filing does not guarantee freedom to operate, but it is a reasonable starting point for a more targeted claim-mapping exercise before committing to a specific formulation route.
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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.