Rotational Molding Patents: Who Leads, Where the Gaps Are 2026
- 48.4% concentration. The top 5 assignees alone account for 147 of the 304 records in scope, with a long tail of single- and few-filing entrants behind them.
- Filings have flattened since 2021. Activity peaked at 17 records in 2021 and sat at 8 by the 2022 midpoint, suggesting the core claim space is largely staked out rather than expanding.
- Medical-device overlap is real. A61F and A61M classes cover roughly 8% of records each, showing rotational molding claims reaching into implants and fluid-handling devices, not just industrial parts.
What the rotational molding patent record shows
Rotational molding patenting in this dataset sits at the intersection of process engineering and material science: claims cover mold rotation and heating cycles under B29C, alongside the polyolefin and additive compositions classified under C08L and C08K that make those cycles work. The 304 records in scope span 2015 through the 2026 cutoff, with receiving offices led by the United States, the European Patent Office and Canada. Publication lags filing by roughly 18 months, so the most recent filing years are undercounted relative to how the field will eventually look.
The picture is one of a mature, moderately concentrated field: a handful of assignees hold a large share of the record base, filing activity has cooled since a 2021 peak, and secondary classes such as A61F, A61M, B32B and B44C point to niche applications — medical devices, layered products, surface finishing — built on top of a stable core process.
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Filing trends and technology composition
Two views of the same 304 records: how filing activity has moved year over year, and how those records distribute across IPC subclasses.
Filing trend, 2017-2026
Filings rose to a peak of 17 records in 2021, then eased to 8 by the 2022 midpoint and continued declining toward the 2026 cutoff, which is itself partial. Read the tail end as incomplete rather than as a genuine drop-off, given the usual 18-month publication lag.
IPC subclass composition
B29C (shaping of plastics) and C08L (polymer compositions) dominate, covering 72.4% and 53.9% of the 304 records respectively. Additive-related C08K and processing-related C08J trail well behind, while A61F, A61M, B32B and B44C each sit near 8%, marking smaller but consistent application niches. Because records can carry multiple classes, these shares sum to well over 100% and should not be read as a single pie.
Shares are the percentage of the 304 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Rotational Molding with Eureka
This page is one run against one query. Ask Eureka your own question about rotational molding and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative filing and most-cited prior art
Polymer compositions having densification accelerators and rotational molding processes for making hollow articles therefrom (US20250145792A1)
Filed by Cytec Industries, this application claims rotational molding processes that add a densification accelerator — alkoxylated fatty alcohols, esters, amines or amides — to the polymer composition before the standard fill, rotate, heat, cool and demold sequence. The accelerator is positioned to improve how the composition fuses and spreads to the mold walls during the heating step.Published 2025-05-08. Abstract condensed from the original filing.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US6602452B2 | Rotational molding of medical articles | 125 |
| 2 | US6362270B1 | Thermoplastic compositions for durable goods applications | 97 |
| 3 | US5530055A | Nucleated polyolefin-based composition for rotational molding | 92 |
| 4 | US5746961A | Method for enhancement of the surfaces of molded plastic products | 67 |
| 5 | US5498307A | In-mold labeling using an adhesive | 61 |
| 6 | US20040010225A1 | Rotationally molded medical articles | 55 |
| 7 | US5532282A | Polyolefin-based composition for rotational molding | 51 |
| 8 | US5783611A | Composition and process for rotational molding foamed articles | 46 |
| 9 | US20020077401A1 | Thermoplastic compositions for durable goods applications | 45 |
| 10 | US4123307A | Method for forming hollow shells by rotational casting and winding thereon | 42 |
Citation counts reflect influence within the searched corpus and skew toward older records; they are not a measure of current commercial importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three findings shape where new claims still have room to land.
The top of the field is dense
With the top 5 assignees holding 147 of 304 records and the top 10 holding 188 (61.8%), new entrants filing squarely on core mold-rotation or base polyolefin composition claims are filing into occupied ground.
Growth has plateaued, not accelerated
Filing volume crested in 2021 and had eased to 8 by the 2022 midpoint. Several leading assignees show zero filings in the latest tracked year, though the tail end of any trend understates true activity due to publication lag.
Medical and layered-product niches persist
Implant, fluid-device, laminate and surface-finishing classes each hold a steady single-digit share of records, indicating rotational molding claims have carved durable footholds outside industrial tanks and containers.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to rotational molding, with the prior art for and against each one.
Who is filing, and where the gaps sit
The ranked leaders account for a little over 60% of records between the top 10 and roughly half between the top 5; behind them the field thins out quickly into single- and low-filing entrants.
A single filer holds a clear lead
The leading assignee's 53 records sit well ahead of fifth place at 11 and tenth place at 7, a steep drop that marks a genuine leader rather than a crowded top tier.
A long tail beyond the leaders
Beyond the top 10, the ranking (the entire 100-entity list the dataset returns, not a top-50 or top-100 cut) thins into occasional filers, consistent with a technology where core claims are settled and most participants file defensively or narrowly.
Co-filing is limited but present
Only nine co-assignee pairs appear in the dataset, with the strongest pairing linked to five shared records, suggesting most filings in this space are pursued independently rather than through joint development.
| Assignee | Recent year | YoY |
|---|---|---|
| Total Petrochemicals Research Feluy | 0 | — |
| Nova Chemicals (International) S.A. | 0 | — |
| STEVENSON MICHAEL J | 0 | — |
| MCGHAN MEDICAL | 0 | — |
| Allergan, Inc. | 0 | — |
| Cytec Technology Corp. | 0 | — |
| MAZIERS ERIC | 0 | — |
| Dow Global Technologies LLC | 0 | — |
Where to take this analysis
The dataset points to a field with settled core claims and a few specific pockets still open. Two directions follow from that.
Map claim scope against the leader's portfolio
With one assignee holding 53 of 304 records, understanding the exact claim boundaries of that portfolio is the first step before filing anywhere near mold-rotation or base composition claims.
Explore assignee portfolios in EurekaTest white-space claims in the under-claimed branches
Densification accelerators, wall-thickness uniformity control and bubble-removal process claims show thinner coverage than the core B29C/C08L classes and warrant a closer novelty check.
Run a novelty search in EurekaCommon questions about rotational molding patents
One assignee leads the ranked field with 53 records, well ahead of the fifth-place holder at 11 and tenth place at 7. That gap indicates a genuine market leader rather than a crowded top tier, and it means any new filing near core process or base polyolefin composition claims should be checked against that leader's portfolio first. The top 5 assignees combined hold 147 of the 304 records in scope, or 48.4%, so concentration is real but not absolute — a long tail of smaller filers still exists beyond the leaders.
Filing activity peaked at 17 records in 2021 and had eased to 8 by the 2022 midpoint, with several leading assignees showing zero filings in the most recent tracked year. That points to a plateau rather than continued growth. It is worth remembering that publication typically lags filing by around 18 months, so the very latest years in any trend chart will always look thinner than they eventually turn out to be once pending applications publish.
Within the 304 records in scope, B29C (shaping of plastics) covers 72.4% and C08L (polymer compositions) covers 53.9%, confirming that process and material claims dominate. Beyond that core, additive-related C08K appears in 19.1% of records, and smaller but consistent shares near 8% each show up in A61F (implants), A61M (body-fluid devices), B32B (laminates) and B44C (surface finishing) — evidence that rotational molding claims extend meaningfully into medical devices and layered or decorated products.
The thinner classes relative to the core process and composition groups — surface decoration overlapping B44C, wall-thickness uniformity control, bubble-removal process steps, and densification accelerator chemistries like the ones in the 2025 Cytec filing — show lower record density than base mold-rotation or polyolefin composition claims. That does not guarantee novelty, but it flags where fewer prior filings compete for claim scope, which is where a freedom-to-operate or novelty search is most worth the effort.
It is moderately concentrated: the top 5 assignees hold 48.4% of the 304 records in scope, and the top 10 hold 61.8%. That leaves a substantial share of records, roughly two-fifths, spread across a long tail of the remaining ranked entities and unranked occasional filers. Co-filing is uncommon — only nine co-assignee pairs appear in the dataset, with the strongest linked to five shared records — so most participants are filing independently rather than through joint ventures.
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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.