Paper Coating Patents: Leaders, Trends & White Space 2026
- Filing has cooled since its 2017 peak. The trend runs from 13 families in 2017 to a flat midpoint of 4 in 2022, with no assignee showing recent-year momentum — a mature, largely settled claim landscape rather than a growing one.
- Chemistry, not paper science, dominates the IPC mix. C09D coatings, C08F addition polymers and C08L polymer compositions together outnumber the core D21H pulp-and-paper class subcategories, showing the real competitive ground is in binder and latex chemistry.
- Citation weight sits on pigment and starch patents from the 1980s-2000s. The most-cited records — precipitated calcium carbonate pigments, starch graft polymers, multi-shell emulsion particles — are decades old, meaning newer filings are building on, not replacing, that prior art.
A chemistry-heavy field built on aging pigment and binder patents
Paper coating and surface treatment patents cover the formulations and processes that give paper and paperboard properties it does not have on its own: print holdout, grease resistance, gloss, and controlled coat weight. The search underlying this landscape spans 1,027 patent families filed between 2015 and the 2026 data cut-off, concentrated under IPC class D21H alongside coatings (C09D), addition and condensation polymers (C08F, C08G, C08L), and inorganic pigment treatment (C09C). That spread signals a field where paper machinery is a secondary concern and polymer and pigment chemistry is the primary battleground.
Filing activity peaked in 2017 and has not recovered; by the 2022 midpoint, annual filings had dropped to a fraction of that peak. Because publication typically lags filing by around 18 months, the final one or two years in any trend understate real activity, but even accounting for that lag the multi-year decline from the 2017 peak is a genuine signal, not a data artefact.
Filing trends and technology composition
The filing curve and the IPC breakdown together show a field where the claim space has been staked out already and current activity is largely defensive or incremental.
A peak in 2017, then a steady decline
Annual filings ran from 13 in 2017 down to 4 at the 2022 midpoint and toward zero in the most recent, still-partial year. This is not a field in an early filing rush; it reads as post-peak, with recent-year momentum flat across every major assignee tracked.
Chemistry classes outweigh the core paper class
D21H accounts for nearly the entire dataset by design of the search, but C09D coatings (300 records), C08F addition polymers (221) and C08L polymer compositions (218) show that most inventive activity sits in the binder, latex and pigment-carrier chemistry layered onto the paper substrate, with C04B ceramics and B41M printing process classes trailing as smaller, more specialised pockets.
Shares are the percentage of the 1,027 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Paper Coating and Surface Treatment with Eureka
This page is one run against one query. Ask Eureka your own question about paper coating and surface treatment and every answer comes back with the patent numbers behind it.
Try EurekaThe prior art carrying the most citation weight
Liquid starch dispersions for coated paper and paperboard (US20030173045A1)
The filing describes a liquid starch dispersion for paper coating combining 5-50% by weight starch, including 20-100% cationic starch, engineered to hold a stable 25°C viscosity of 500-2500 cps both initially and after 90 days of room-temperature storage. The preferred blend pairs cationic starch with ASA starch, positioning the dispersion as a rheology modifier, structurant and binder in a single coating formulation.Filed by National Starch and Chemical Investment Holding Corporation, published 2003-09-18.
View full record| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | EP1712523A1 | Precipitated calcium carbonate pigment, especially for use in inkjet printing paper coatings | 197 |
| 2 | US5879442A | Aqueous slurry of precipitated calcium carbonate and ground calcium carbonate in combination | 109 |
| 3 | US5273824A | Cored multi-shell emulsion particle | 95 |
| 4 | US4617239A | Paper coating agent | 91 |
| 5 | US5003022A | Starch graft polymers | 85 |
| 6 | EP0850880A1 | Aqueous slurry precipitated calcium carbonate and ground calcium carbonate in combination | 81 |
| 7 | US20040034147A1 | Hollow polymer particle, process for producing the same, paper coating composition using the same, coated pap… | 79 |
| 8 | US5726259A | Bimodal latex binder | 79 |
| 9 | US5085707A | Defined and delaminated kaolin product | 78 |
| 10 | US6402826B1 | Kaolin clay pigment for paper coating and method for producing same | 70 |
Citation counts inside a searched corpus favour older, earlier-filed records; treat this table as a map of foundational influence, not of current filing activity.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers mean for a filing decision
Three patterns matter more than the headline family count: where the claim density actually sits, how citation weight is distributed, and how little movement there has been in recent years.
A post-peak field, not a growing one
Annual filings fell from a 2017 peak of 13 to 4 at the 2022 midpoint, trending toward zero in the most recent partial year. Even allowing for an 18-month publication lag understating the tail, the multi-year decline from peak is real and suggests the core claim space is largely staked out.
Binder and latex chemistry outweighs paper-specific claims
Coating formulations (C09D), addition polymers (C08F) and polymer compositions (C08L) together represent more inventive volume than most sub-branches of the core D21H class, confirming that competitive differentiation is happening in the chemistry applied to the sheet, not the sheet itself.
Foundational pigment and starch patents still anchor the field
The most-cited records are precipitated calcium carbonate pigment and starch-graft chemistries filed well before the 2015 window opens. New filings sit downstream of this art rather than displacing it, which raises freedom-to-operate questions for anyone claiming pigment or starch-based coating formulations.
Filing is spread across three major offices with no single hub
Japan, the United States and the EPO each carry a substantial share of receiving-office filings, with Canada, Australia and PCT filings trailing behind. That spread means freedom-to-operate work needs to clear at least three major jurisdictions rather than one dominant office.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to paper coating and surface treatment, with the prior art for and against each one.
Assignee landscape and where activity has gone quiet
No tracked assignee shows filing activity in the most recent year, and co-assignment pairs are few and mostly linked entities, pointing to a field with limited fresh competitive entry.
Recent-year filing has gone flat across the board
Every assignee tracked for recent-year momentum — including the largest historical filers in polymer and pigment chemistry — shows zero filings in the latest year of the dataset. Combined with the post-2017 decline, this points to a field where the incumbents have largely stopped adding to their portfolios rather than one being contested by new entrants.
Co-filing is rare and concentrated within corporate families
Only ten co-assignee pairs appear across the dataset, and the strongest pairs link entities that share a corporate lineage rather than independent competitors filing jointly. This suggests most of the invention work happens inside single organisations, with little cross-licensing or joint-venture patenting.
A wide base of single or low-volume filers
With over a thousand families spread across eight IPC subclasses and six receiving offices, much of the filing volume comes from entities outside the small set of assignees tracked for momentum, indicating a long tail of specialised or one-off filers rather than a field dominated by a handful of players.
| Assignee | Recent year | YoY |
|---|---|---|
| Dow Chemical Company | 0 | — |
| BASF SE | 0 | — |
| JSR Corporation | 0 | — |
| Sumitomo Chemical Co., Ltd. | 0 | — |
| Lamberti S.p.A. | 0 | — |
| Omya International AG | 0 | — |
| Asahi Kasei Corporation | 0 | — |
| International Rayon Company | 0 | — |
Where to take this analysis
The dataset points to a settled but still chemically active field. The next steps depend on whether the goal is freedom-to-operate clearance or identifying an open filing position.
Run a freedom-to-operate check on pigment and starch claims
The heaviest-cited prior art covers precipitated calcium carbonate pigments and starch graft polymers; any coating formulation touching either chemistry should be checked against this cluster before filing.
Explore prior art in Eureka →Map the under-claimed branches against your own formulation
Grease-barrier, recyclable-barrier and bio-based sizing sub-areas show thinner coverage relative to the pigment and latex core; a targeted search will show whether a specific formulation route is genuinely open.
Search white space in Eureka →Track whether the post-2017 decline reverses
With every major assignee flat in the latest year, a renewed filing push from any one of them would be a meaningful signal worth monitoring going forward.
Set up monitoring in Eureka →Common questions on paper coating patents
The assignee base in this dataset is broad, spanning large chemical companies with historical filings in polymer and pigment chemistry alongside a long tail of smaller or single-filing entities. None of the largest tracked assignees show filing activity in the most recent year, so leadership here is better read as historical claim density than as current competitive push. Anyone assessing the field should look at both the cumulative family count for each assignee and how recently they last filed, since the two tell different stories.
Annual filings peaked at 13 in 2017 and fell to 4 by the 2022 midpoint, trending toward zero in the most recent, still-partial year. Part of that tail-end drop is a publication lag artefact, since filings typically take around 18 months to publish, but the multi-year decline from the 2017 peak predates that lag window and looks like a genuine slowdown. A plausible explanation is that the core pigment, starch and latex coating chemistries were heavily claimed in the preceding decade, leaving less open ground for incremental filings.
Beyond the core pulp-and-paper class D21H, the largest concentrations sit in coatings and inks (C09D, 300 records), addition polymers such as vinyl-based latexes (C08F, 221 records), and general polymer compositions (C08L, 218 records). Inorganic pigment treatment (C09C) and condensation polymers (C08G) follow as smaller but still substantial categories. This distribution shows that most inventive effort in paper coating is really binder, latex and pigment chemistry applied to a paper substrate rather than paper-specific engineering.
US20030173045A1 covers a liquid starch dispersion for paper and paperboard coating, specified by a starch content of 5-50% by weight including 20-100% cationic starch, and a defined viscosity range of 500-2500 cps at 25°C that must hold both initially and after 90 days of storage. Filed by National Starch and Chemical Investment Holding Corporation, it is fairly narrow: it blocks dispersions that fall inside both the compositional ratio and the specific viscosity-stability window it claims. Formulations using different cationic-starch ratios, different viscosity targets, or non-starch structurants sit outside its claims, though anyone working with cationic/ASA starch blends for coating should check the full claim set against their formulation.
The densest claim clusters sit around pigment carriers like precipitated calcium carbonate and starch-based binders, both anchored by decades-old, heavily cited prior art. Thinner coverage in this dataset shows up in fluorochemical-free grease-barrier coatings, recyclable barrier formulations, and bio-based sizing agents aimed at compostable paper — all adjacent to the dense core but not yet saturated. A targeted novelty search on any of these sub-areas is a reasonable first step before committing to a filing strategy.
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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.