D21C 3/02
Pulping cellulose-containing materials: with inorganic bases or alkaline reacting compounds
Official title: with inorganic bases or alkaline reacting compounds, e.g. sulfate processes
D21C3/02 (Pulping cellulose-containing materials: with inorganic bases or alkaline reacting compounds) appears on 387 US grants and 490 published applications in this corpus.
Search patents in D21C- Granted patents
- 387
- Published applications
- 490
- Assignees
- 284
- Inventors
- 1,013
- Latest grant
- 14 Jul 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 4 | 0 |
| 1977 | 1 | 0 |
| 1978 | 5 | 0 |
| 1979 | 0 | 0 |
| 1980 | 1 | 0 |
| 1981 | 1 | 0 |
| 1982 | 0 | 0 |
| 1983 | 0 | 0 |
| 1984 | 2 | 0 |
| 1985 | 1 | 0 |
| 1986 | 0 | 0 |
| 1987 | 1 | 0 |
| 1988 | 2 | 0 |
| 1989 | 7 | 0 |
| 1990 | 9 | 0 |
| 1991 | 6 | 0 |
| 1992 | 1 | 0 |
| 1993 | 4 | 0 |
| 1994 | 6 | 0 |
| 1995 | 3 | 0 |
| 1996 | 7 | 0 |
| 1997 | 6 | 0 |
| 1998 | 6 | 0 |
| 1999 | 4 | 0 |
| 2000 | 7 | 0 |
| 2001 | 11 | 4 |
| 2002 | 13 | 20 |
| 2003 | 12 | 11 |
| 2004 | 11 | 11 |
| 2005 | 3 | 13 |
| 2006 | 7 | 8 |
| 2007 | 1 | 15 |
| 2008 | 2 | 12 |
| 2009 | 3 | 8 |
| 2010 | 3 | 20 |
| 2011 | 6 | 22 |
| 2012 | 18 | 23 |
| 2013 | 13 | 19 |
| 2014 | 21 | 26 |
| 2015 | 15 | 35 |
| 2016 | 17 | 25 |
| 2017 | 13 | 30 |
| 2018 | 18 | 11 |
| 2019 | 16 | 23 |
| 2020 | 9 | 17 |
| 2021 | 14 | 21 |
| 2022 | 10 | 24 |
| 2023 | 9 | 25 |
| 2024 | 17 | 22 |
| 2025 | 31 | 25 |
| 2026 | 10 | 20 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
Recent patents
- Process and system for producing pulp, energy, and bioderivatives from plant-based and recycled materials14 Jul 2026US 12,678,759 B2Circ, LLC
- Process for producing and using fibrillated biodegradable microfibers7 Jul 2026US 12,674,278 B2
- Extraction of delignified, cellulose-based fibers from natural plant material, and materials incorporating such fibers12 May 2026US 12,624,500 B2University of Maryland, College Park
- Process and system for producing pulp, energy, and bioderivatives from plant-based and recycled materials28 Apr 2026US 12,611,644 B2Circ, LLC
- Paper pulp, a method for producing paper pulp, and paper pulp products31 Mar 2026US 12,590,411 B2ShenZhen YUTO Packaging Technology Co., Ltd.
- Process and System for Producing Pulp, Energy, and Bioderivatives from Plant-Based and Recycled Materials10 Sep 2026US 2026/0264040 A1Circ, LLC
- Method of Preparing High-Strength, High-Toughness, and Recyclable Fiberboard with Bionic Structure3 Sep 2026US 2026/0258602 A1Northeast Forestry University
- Chemical wood pulp with enhanced tensile strength6 Aug 2026US 2026/0226685 A1SöDra SkogsäGarna Ekonomisk FöRening
- Preparation of Maple Wood for CTMP Production30 Jul 2026US 2026/0218448 A1Billerud Aktiebolag (publ)
- Maple HT-CTMP30 Jul 2026US 2026/0218449 A1Billerud Aktiebolag (publ)
Most cited
By later US patents
- Lyocell fibers and process for their preparation138US 6,235,392 B1Weyerhaeuser Company · 2001
- Lyocell fibers having enhanced CV properties115US 6,221,487 B1Weyerhauser Company · 2001
- Method of treating lignocellulosic biomass to produce cellulose109US 6,419,788 B1PureVision Technology, Inc. · 2002
- Process for producing a pulp suitable for papermaking from nonwood fibrous materials101US 6,302,997 B1HurterConsult Incorporated · 2001
- Lyocell nonwoven fabric98US 7,067,444 B2Weyerhaeuser Company · 2006