Paper Machine Dewatering Patents: Top Companies & Trends 2026
A data-driven landscape of paper machine dewatering patents: filing trends, leading assignees, IPC technology mix and the most-cited prior art shaping the field.
Filing growth = 2021 (18 records) → 2024 (12); 2024 is the last year we treat as complete. Top-5 share = the 5 largest assignees ÷ all 1,867 records in scope (CR5), not the ranked leaders only.
What paper machine dewatering patents actually cover
Paper machine dewatering sits at the mechanical heart of papermaking: forming fabrics, felts, presses and vacuum systems that pull water out of a moving web before it ever reaches a dryer section. The dataset behind this page draws on 1,867 published records spanning 2015 through the current filing year, captured wherever claims or titles tie machine-level dewatering or filtration directly to pulp, papermaking or paper machine terminology. That scope pulls in both the mechanical engineering side — forming sections, press felts, calenders — and the chemistry side, where additive and polymer patents claim faster drainage through composition rather than hardware.
Because publication lags filing by roughly 18 months, the most recent one or two years in any trend understate real activity; treat 2024 as the last complete year and read anything later as still filling in.
Filing trend and technology composition
Two views of the same 1,867-record dataset: how filing volume has moved year over year, and which IPC subclasses carry the claim density.
Filing trend, 2017 to present
Filings rose to a peak of 44 in 2018, then eased; the 2021-to-2024 comparison shows a move from 18 to 12 filings, a 33% decline over that span. Later years in the chart are still being backfilled by publication lag and should not be read as a continued fall.
Publication lags filing by roughly 18 months, so 2025 onwards are still filling in. Growth rates on this page therefore end at 2024; running them to the last bar would understate the field.
IPC subclass distribution
D21F (paper-making machines) appears on 71.2% of all records, confirming that most activity is claimed at the machine and forming-section level rather than in pulp chemistry alone. D21H (pulp and paper compositions) still reaches 27.8%, and smaller subclasses such as B32B laminates, D03D woven fabrics and B01D separation processes each sit under 5%, marking narrower but still active claim territory.
Shares are the percentage of the 1,867 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Pulp & Papermaking: Paper Machine Dewatering Patent Landscape with Eureka
This page is one run against one query. Ask Eureka your own question about pulp & papermaking: paper machine dewatering patent landscape and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative filing and most-cited records
Method of using aldehyde-functionalized polymers to enhance paper machine dewatering
The invention provides a composition which comprises one or more aldehyde-functionalized polymers comprising amino and/or amido groups wherein at least about 15 mole percent of the amino and/or amido groups are functionalized by reacting with one or more aldehydes. The composition optionally additionally comprises at least about 60 mole percent unreacted aldehyde. In addition, the invention provides a method of enhancing a papermaking process, the method comprising adding the composition in the papermaking process.Filed by Nalco Company, this record exemplifies the chemistry-side approach to dewatering: claiming a polymer composition and its dosing method rather than a mechanical component.
View full record| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US3817827A | Soft absorbent fibrous WEBS containing elastomeric bonding material and formed by creping and embossing | 340 |
| 2 | US6287426B1 | Paper machine for manufacturing structured soft paper | 321 |
| 3 | US4605585A | Forming fabric | 295 |
| 4 | US5932068A | Soft tissue | 225 |
| 5 | US5372876A | Papermaking felt with hydrophobic layer | 220 |
| 6 | WO2000047628A2 | Derivatized microfibrillar polysaccharide | 183 |
| 7 | US5054525A | Double layer forming wire fabric | 181 |
| 8 | US5865955A | Method and device for enhancing the run of a paper web in a paper machine | 178 |
| 9 | US4483745A | Method and apparatus of sheet transfer using a nonporous smooth surfaced belt | 170 |
| 10 | US5182164A | Wet press felt to be used in papermaking machine | 168 |
Citation counts favour older filings that have had more time to accumulate citations within the searched corpus; treat them as a measure of influence on later filings, not as a ranking 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 concentration and class data mean for filing strategy
The ranking and IPC breakdown point to a field with a dominant machine-side incumbent, a long tail of single-digit filers, and chemistry claims still open at the margins.
Leadership is real but not exclusive
The leading assignee holds 123 records on its own, well ahead of fifth place at 65 and tenth place at 44. Even so, the top five combined account for only 24.6% of all records in scope, and the top ten for 38.4% — meaning most of the field's filing activity sits outside the ranked leaders, spread across the other 90 companies in the ranking.
Volume has eased from its 2018 peak
Filings peaked at 44 in 2018 and had fallen to 12 by 2024, down from 18 in 2021 — a 33% decline over that three-year window. This reads as a maturing, well-claimed mechanical core rather than a shrinking field: dense prior art in forming and press sections makes new machine-level claims harder to differentiate.
Machine claims dominate, chemistry claims persist
D21F appears on 71.2% of all 1,867 records, confirming the field is anchored in machine and forming-section hardware. D21H pulp and paper compositions still reaches 27.8%, showing that additive and polymer routes to faster drainage remain a substantial, separately claimable path alongside the mechanical one.
Filing is spread across several major offices
The United States leads receiving-office counts at 382, followed by the EPO at 307 and Canada at 200; Finland's 154 and WIPO's 141 point to a field with meaningful European and PCT-route activity alongside the US base, consistent with the historical concentration of paper-machine manufacturing in Northern Europe.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to pulp & papermaking: paper machine dewatering patent landscape, with the prior art for and against each one.
Where to take this analysis
The dataset points to specific questions worth running down before committing R&D or freedom-to-operate budget.
Map the chemistry-side white space
D21H compositions sit at 27.8% of records against D21F's 71.2%, and narrower subclasses like B01D separation processes sit under 5% — worth checking whether that gap is genuinely open or simply under-searched by this string.
Explore composition claims in EurekaTrack the long tail below the ranked leaders
With the top ten holding only 38.4% of all 1,867 records, most filing activity sits outside the ranking — a useful signal for identifying emerging entrants before they consolidate.
Run an assignee deep-dive in EurekaWatch for the 2025–2026 publication catch-up
Because publication lags filing by roughly 18 months, the apparent slowdown after 2024 will partly reverse as later filings publish — re-check the trend in a future refresh rather than treating current-year counts as final.
Set a monitoring alert in EurekaCommon questions about paper machine dewatering patents
One assignee leads the ranked field with 123 records, noticeably ahead of fifth place at 65 and tenth place at 44. That said, the top five combined hold only 24.6% of all 1,867 records in scope and the top ten hold 38.4%, so no single company or small group controls the field outright. The ranking covers 100 companies total, and most of the filing volume sits in the long tail below the top ten.
Filings peaked at 44 in 2018 and have since eased, with the 2021-to-2024 window showing a decline from 18 to 12 filings, a 33% drop over that three-year span. That should be read as a maturing, densely claimed mechanical core rather than a collapsing field. Because publication lags filing by roughly 18 months, the very latest years in any chart will always look lower than they will eventually turn out to be, so 2024 is the last year that can be read as complete.
The dataset splits fairly cleanly along IPC lines: D21F, paper-making machines, appears on 71.2% of all records and covers forming fabrics, press sections, felts and vacuum systems. D21H, pulp and paper compositions, appears on 27.8% of records and covers additive and polymer chemistry that improves drainage without changing hardware. Both routes are actively claimed, and a filing can carry classes from both sides at once, which is why the two shares add to more than 100%.
The narrower IPC subclasses are the starting point: B01D separation processes sits at 3.1% of records, D04H nonwovens and felts at 2.1%, and D03D woven fabrics at 3.9%, all well below D21F's 71.2% concentration. Low share does not automatically mean easy filing, since some of these areas may simply be under-searched by the dataset's terms rather than genuinely open. A freedom-to-operate search against the specific claim language in those subclasses is the necessary next step before assuming white space exists.
AU2005208709B2, assigned to Nalco Company, claims a composition of aldehyde-functionalized polymers, with at least about 15 mole percent of amino or amido groups functionalized by reaction with aldehydes, plus a method of adding that composition during papermaking to enhance dewatering. It represents the chemistry-side route to faster drainage rather than a mechanical redesign, and it is representative of a broader set of additive-and-dosing claims that sit alongside the machine-level patents in this dataset. Anyone filing a similar polymer-dosing approach for dewatering enhancement should review its specific mole-percent thresholds closely.
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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.