Viscose and Lyocell Fiber Patents: Who Leads, Where the Gaps Are 2026
- One filer dominates. The leading assignee alone accounts for 34 of 59 records in scope, well ahead of anyone else in the ranking.
- Filing has cooled since 2019. Activity peaked at 20 records that year and has since fallen back toward single digits, with the midpoint year at just 4.
- Concentration is extreme at the top. The top 5 assignees combined hold 81.4% of all 59 records in scope, and the top 10 hold 93.2% — there is almost no long tail left to search.
What this landscape covers
This landscape tracks patent activity at the intersection of viscose fiber production, lyocell fiber processing, and regenerated cellulose fiber manufacture, filtered to documents that address NMMO solvent recovery, carbon disulfide emission, fibrillation tendency, pulp raw material selection, or closed-loop process design. The scope is narrow by design: it isolates the process chemistry and fiber-treatment claims that determine whether a regenerated cellulose fiber process is commercially and environmentally viable, rather than the broader universe of cellulose fiber patents.
Fifty-nine records sit in scope, spanning 2015 through the 2026 cut-off. Because publication typically lags filing by around eighteen months, the most recent one to two years understate real filing activity — the apparent decline after 2019 is real in direction but likely less steep than the raw counts suggest.
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Filing trend and technology composition
Two views of the same 59 records: how filing activity moved year over year, and which IPC subclasses carry the claim density.
Filing trend, 2017–2026
Filings rose from a single record in 2017 to a peak of 20 in 2019, then declined toward a midpoint of 4 in 2022. The 2026 figure of 0 reflects the partial year and publication lag rather than a sudden stop.
Technology composition by IPC subclass
D01F (chemical filament and fibre features) covers 93.2% of the 59 records, confirming this is fundamentally a fiber-composition field. D04H (nonwovens), D21H (pulp and paper compositions) and D06M (textile chemical treatment) each sit in the 17-25% range, marking the main adjacent claim areas rather than the core.
Shares are the percentage of the 59 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Viscose and Lyocell Fiber Production with Eureka
This page is one run against one query. Ask Eureka your own question about viscose and lyocell fiber production and every answer comes back with the patent numbers behind it.
Try EurekaThe documents anchoring this field
Lyocell fiber treatment method (US5562739A)
The fibrillation tendency of lyocell fibre can be reduced by application to the fibre of a solution of a chemical reagent which contains at least two aliphatic aldehyde groups capable of reacting with each other in aqueous solution to form a cyclic hydrate containing a -CHOH-O-CHOH- linkage, followed by reaction between the fibre and the reagent. The protection afforded by the invention is retained upon repeated laundering.Filed by Courtaulds Fibres (Holdings) Limited, this document sits among the most-cited records in scope and defines a chemical-crosslinking route to fibrillation control that later filings had to design around.
View full record| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5725821A | Process for the manufacture of lyocell fibre | 199 |
| 2 | US5562739A | Lyocell fiber treatment method | 92 |
| 3 | US5520869A | Treatment of fibre | 43 |
| 4 | CN104005225A | 一种减少lyocell纤维素纤维原纤化倾向的方法 | 22 |
| 5 | US20210010163A1 | Lyocell fiber with increased tendency to fibrillate | 7 |
| 6 | CN117822140A | 一种大麻浆粕莱赛尔纤维及其制备方法 | 6 |
| 7 | JP1996049167A | Method for processing fiber | 5 |
| 8 | US20210002802A1 | Lyocell fiber with viscose like properties | 4 |
| 9 | WO2019170732A1 | Lyocell fiber with increased tendency to fibrillate | 4 |
| 10 | KR1020030004395A | Lyocell fibers | 4 |
Citation counts favour older documents in any searched corpus; treat them as a signal of foundational influence, not of current commercial relevance.
Patent titles are shown in the language they were filed in, not translated, so that each record stays verifiable against the original filing — a translated title will not match in Eureka or in any national register. 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
Read together, the concentration figures and the technology composition point to a field where the core process chemistry is locked up and the remaining room sits in adjacent applications.
The core is not open ground
With the top 5 assignees holding 81.4% of all 59 records and the top 10 holding 93.2%, new entrants attempting a core fibrillation-control or NMMO-recovery claim are filing directly against the densest part of the field.
Filing has slowed from its 2019 peak
Activity peaked at 20 records in 2019 and had fallen to 4 by the 2022 midpoint. Several of the largest assignees show 0 filings in the latest year, with some down 100% year over year — though publication lag means the very latest years are always undercounted.
This is a fiber-composition field first
D01F chemical filament and fibre features covers 93.2% of the 59 records in scope, dwarfing the next largest subclass. The adjacent classes — nonwovens, pulp compositions, textile chemical treatment — each sit at a fraction of that density and represent where secondary claims are being built.
Co-filing is rare and mostly intra-group
Only three co-assignee pairs appear across the dataset, and the strongest of them links two entities that appear to be affiliated group companies rather than independent collaborators. Cross-company joint filing is not a meaningful pattern here.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to viscose and lyocell fiber production, with the prior art for and against each one.
Who holds the claims
Seventeen companies make up the entire ranked list the data endpoint returns for this scope — this is not a top-50 or top-100 cut, it is the whole field as filed.
One assignee sets the baseline
The leading assignee holds 34 of the 59 records in scope, a scale no other filer in the ranking approaches — fifth place holds only 2 and tenth place holds 1.
A short, steep ranking
The ranking runs to only seventeen companies total, and it drops from double digits to single-digit and then to one-record filers very quickly. There is little room between the leader and everyone else.
Even leaders have gone quiet recently
Several of the largest historical filers, including group-affiliated entities tied to the top assignees, show zero filings in the latest year and year-over-year declines of 100%. This tracks the broader post-2019 slowdown rather than any single company's exit.
| Assignee | Recent year | YoY |
|---|---|---|
| Lenzing AG | 0 | -100% |
| Courtaulds Fibres (Holdings) Limited | 0 | — |
| Lenzing Fibers Limited | 0 | — |
| Grasim Industries Limited | 0 | — |
| Lenzing Fibers Limited | 0 | — |
| Yibin Grace Group Co., Ltd. | 0 | -100% |
| Weyerhaeuser Company | 0 | — |
| Sichuan Silaiya Fiber Technology Co., Ltd. | 0 | — |
Where to take this from here
The concentration and composition figures point to specific next steps depending on whether the goal is freedom-to-operate or identifying open claim space.
Map the leader's full claim set
With one assignee holding 34 of 59 records, a freedom-to-operate review should start by pulling that assignee's complete claim history in D01F before scoping any new fiber-treatment or fibrillation-control filing.
Run an assignee deep-dive in EurekaCheck the under-claimed branches
Nonwoven-grade blends, dye-uptake modification and pulp pretreatment show materially lower filing density than the core fiber-treatment claims and merit a closer prior-art check before drafting.
Explore white space in EurekaTrack the post-2019 slowdown
Filing fell from a 2019 peak of 20 to a midpoint of 4 in 2022, with several leaders at zero in the latest year. Confirm whether this reflects market consolidation or a shift in filing strategy before assuming the field is closing.
Monitor filing trends in EurekaCommon questions on this landscape
The ranked list for this scope contains seventeen companies, and it is heavily front-loaded: the leading assignee alone holds 34 of the 59 records in scope, far more than any other filer. The top 5 assignees combined hold 81.4% of all records, and the top 10 hold 93.2%, so the field has almost no meaningful long tail beyond the leading group. Anyone assessing competitive position in this space should treat the leader's portfolio, not the broader ranking, as the primary reference point.
Filing activity peaked in 2019 at 20 records and had declined to a midpoint of 4 by 2022, with several of the largest historical assignees showing zero filings and year-over-year declines of 100% in the latest year. This points to a slowdown rather than growth, though publication lag of roughly eighteen months means the most recent one to two years in any dataset understate true filing activity. The honest read is a mature, consolidating field rather than an expanding one.
D01F, covering chemical filament and fibre features, appears in 93.2% of the 59 records in scope, making it the dominant classification by a wide margin. Nonwovens and felts (D04H), pulp and paper compositions (D21H), and textile chemical treatment (D06M) each cover a meaningfully smaller share of records and represent secondary claim areas built around the core fiber chemistry. Because a single record can carry multiple IPC classes, these shares add up to more than 100% and should not be read as parts of a whole.
US5562739A, held by Courtaulds Fibres (Holdings) Limited, claims a method of reducing lyocell fiber fibrillation tendency by applying a chemical reagent with at least two aliphatic aldehyde groups that react to form a cyclic hydrate linkage with the fibre, with the effect surviving repeated laundering. It is one of the most-cited records in this dataset, which signals it is a frequently referenced prior-art anchor for fibrillation-control chemistry specifically, not for lyocell production broadly. A new filing using a different reagent chemistry or a physical rather than chemical fibrillation-control mechanism would sit outside its specific claim language, but any aldehyde-based crosslinking approach needs a careful design-around review against it.
The composition data shows claim density concentrated heavily in D01F fiber-composition claims, with materially thinner coverage in adjacent branches such as nonwoven-grade lyocell blends, dye-uptake modification for regenerated cellulose, and pulp raw-material pretreatment. Co-assignee filing is also rare, with only three identified pairs in the whole dataset, suggesting little cross-company collaboration to date and room for a new entrant to partner rather than compete head-on. A practical starting point is to check these under-claimed branches against the leading assignee's existing portfolio before scoping a new filing.
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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.