Solvent Recovery in Cellulose Fibre Spinning Patents: Leaders & Trends 2026
- Filing peaked in 2021 at 13 records then fell to 2 by 2024, an 85% drop over that three-year span — the sharpest contraction in the dataset.
- One assignee holds 16 of the 39 families far ahead of a long tail where fifth and tenth place both sit at just 2 filings each.
- Separation and hydrocarbon-refining classes dominate B01D and C07C each cover over 40% of records, while polysaccharide-specific class C08B appears in only one filing.
Filing growth compares 2021 (13 records) with 2024 (2) — 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.
What this landscape covers
This dataset tracks patent families addressing solvent recovery in cellulose fibre spinning — recovering and recycling process solvents such as amine oxides, purge-stream treatment, and spin-bath regeneration, with emphasis on impurity accumulation, degradation-product removal, and makeup-solvent cost. The scope spans 39 published records filed between 2015 and mid-2026, drawn from receiving offices including the United States, WIPO/PCT, Canada, China, Europe and India.
Because the underlying processes originate in industrial chemistry and refining as much as in textile fibre production, the assignee base leans toward chemical-process and engineering firms rather than fibre producers themselves. That cross-industry pull shapes both the technology composition and the concentration of filings.
Filing trend and technology composition
Publication lags filing by roughly 18 months, so the most recent one to two years in any trend chart will always look thinner than the true filing rate turns out to be once records catch up.
A sharp rise, then a sharp pullback
Filings rose from 4 in 2017 to a peak of 13 in 2021, then declined to 2 by 2024 — an 85% drop across that span. Readings for 2025 and 2026 are still incomplete and should not be read as a continuation of that decline.
Separation and hydrocarbon chemistry lead the claim space
B01D (separation processes) and C07C (acyclic and carbocyclic compounds) each appear in over 40% of the 39 records in scope, with C10G (hydrocarbon oils and refining) close behind at 30.8%. Classes specific to cellulose chemistry, such as C08B, appear in only one record — a sign that most of the claim density sits in general-purpose separation and refining engineering rather than fibre-specific processing.
Shares are the percentage of the 39 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Solvent Recovery in Cellulose Fibre Spinning with Eureka
This page is one run against one query. Ask Eureka your own question about solvent recovery in cellulose fibre spinning and every answer comes back with the patent numbers behind it.
Try EurekaRepresentative filing and most-cited prior art
Process and facility for recovering methoxypropanols from an aqueous stream
A process for recovering 1-methoxy-2-propanol and 2-methoxy-1-propanol from an aqueous effluent stream by liquid-liquid extraction, followed by extractive distillation, distillation of methoxypropanols from the extraction solvent, and distillative separation of the methoxypropanol isomers. Recovered extraction solvent is recycled to the extraction and extractive distillation steps, and heat transfer from the recovered solvent to the extract fed to the extractive distillation reduces the energy demand of the process.Filed by Evonik Operations, 2023-04-20 (US20230122837A1).
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5496395A | System for recovering organic solvent in soil | 44 |
| 2 | US20190112535A1 | Method for purifying an asphaltene-containing fuel | 15 |
| 3 | WO2005040308A2 | Method and apparatus for converting and removing organosulfur and other oxidizable compounds from distillate … | 15 |
| 4 | US7820031B2 | Method and apparatus for converting and removing organosulfur and other oxidizable compounds from distillate … | 14 |
| 5 | US20070221538A1 | Method and Apparatus for Converting and Removing Organosulfur and Other Oxidizable Compounds from Distillate … | 10 |
| 6 | US5118328A | Process for regenerating adsorbers | 7 |
| 7 | US20150122703A1 | Fouling reduction in supercritical extraction units | 2 |
| 8 | CN116688636A | 一种带有过滤结构的溶剂回收用浓缩装置 | 1 |
| 9 | WO2021204531A1 | Process and facility for recovering methoxypropanols from an aqueous stream | 1 |
Citation counts favour older records within the searched corpus and should be read as a signal of 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. Publication numbers are shown where the record carries one (9 of 9 rows); clicking a row searches Eureka by that number.
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Browse MCP servers →What the filing pattern signals
Three patterns stand out once filing counts and technology classes are set against each other.
One filer dominates a thin field
The leading assignee accounts for 16 of the 39 records in scope, while fifth and tenth place both hold just 2 filings. That gap between the leader and everyone else is wide enough that a newcomer's freedom-to-operate analysis should start with that one portfolio before looking anywhere else.
A peak year, then a steep pullback
Filings hit 13 in 2021 and fell to 2 by 2024, an 85% decline. That contraction lines up with several co-filing partnerships going quiet rather than with the field closing off — it likely reflects a lull between engineering programmes rather than an exhausted technology.
Separation engineering, not fibre chemistry, carries the claims
B01D (separation processes) and C07C (carbocyclic compounds) each cover over 40% of the 39 records, and C10G (hydrocarbon refining) covers 30.8%. Cellulose-specific class C08B shows up once. Most of the patented know-how sits in general separation and refining apparatus that happens to be applied to spin-bath and solvent streams.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to solvent recovery in cellulose fibre spinning, with the prior art for and against each one.
Who is filing, and who is filing together
The ranking below covers all 24 companies the data endpoint returns for this scope — it is not a top-50 or top-100 cut, and most of the field sits well below the leader.
A single chemical-process group leads by a wide margin
The top-ranked assignee holds 16 of the 39 families in scope, built from process-engineering patents around solvent recovery rather than fibre spinning specifically. Its strongest co-filing relationships point to joint work with process-plant engineering partners.
Filings cluster around a small number of joint programmes
Eight co-assignee pairs appear in the dataset, with the strongest pairing linking the leading chemical-process filer to an industrial-solutions engineering partner. That pattern suggests recovery-plant patents here are frequently the product of joint chemical-plus-engineering filing programmes rather than solo R&D.
Recent-year activity has gone quiet across the leaders
Every one of the assignees tracked for recent-year momentum shows zero filings in the latest year — consistent with the broader 2021-to-2024 pullback rather than any single company exiting the space. Given publication lag, this is better read as a filing lull than a closed field.
| Assignee | Recent year | YoY |
|---|---|---|
| Evonik Operations GmbH | 0 | — |
| thyssenkrupp Industrial Solutions AG | 0 | — |
| thyssenkrupp Uhde GmbH | 0 | — |
| Degussa Corp | 0 | — |
| Siemens AG | 0 | — |
| Fraunhofer-Gesellschaft | 0 | — |
| Eastman Chemical Company | 0 | — |
| King Abdullah University of Science and Technology | 0 | -100% |
Where to take this analysis
The filing pattern here raises specific questions worth running down before committing R&D or freedom-to-operate budget.
Map the leader's claim boundaries precisely
With one assignee holding 16 of 39 families, a claim-by-claim read of that portfolio should come before any new filing in this space.
Explore the portfolio in EurekaWatch for the field reactivating
The 2021-to-2024 pullback may be a lull rather than an exit; track new publications as the 2025-2026 filing cohort completes.
Set up monitoring in EurekaTest the under-claimed branches
Cellulose-specific degradation tracking and catalytic purge treatment show thin coverage — worth a focused prior-art search before drafting.
Run a white-space search in EurekaCommon questions about this landscape
One assignee, a chemical-process engineering group, leads with 16 of the 39 families tracked in this dataset. The rest of the field is a long tail: fifth place and tenth place both hold only 2 filings each. This means the leading portfolio is the single most important one to review for freedom-to-operate purposes, since no other filer approaches its scale.
Filings rose from 4 in 2017 to a peak of 13 in 2021, then fell to 2 by 2024 — an 85% decline over that three-year span. However, publication typically lags filing by around 18 months, so the 2025 and 2026 figures in any dataset are still incomplete and should not be read as proof the field is dying. The honest read is a pullback after a 2021 peak, not a confirmed long-term decline.
The two densest IPC subclasses are B01D (separation processes, including filtration) at 43.6% of the 39 records, and C07C (acyclic and carbocyclic compounds) at 41.0%. C10G, covering hydrocarbon oil refining, follows at 30.8%. Because records can carry multiple classes, these figures add to more than 100%, and they show that most patented engineering here overlaps with general separation and refining rather than being cellulose-fibre-specific.
Yes. Classes tied to cellulose-specific chemistry (C08B), contaminated-land solvent reclamation crossover (B09C), and gas-turbine-integrated heat recovery (F02C) each appear in only one to four of the 39 records, well below the B01D/C07C/C10G core. These thinner branches are worth a dedicated prior-art search before drafting, since claim density there is much lower than in the core separation and refining classes.
US20230122837A1 describes a process for recovering methoxypropanol solvents from an aqueous effluent stream using liquid-liquid extraction followed by extractive distillation, with the recovered solvent recycled back into the process and used to preheat the extract feed to cut energy demand. It is a process-and-facility claim rather than a composition claim, meaning it primarily blocks specific extraction-and-recycle plant configurations rather than the underlying solvent chemistry itself. Anyone designing a similar recovery train should check its claim scope on column configuration and heat-integration steps specifically.
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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.