D21C 3/00
Pulping cellulose-containing materials
Official title: Pulping cellulose-containing materials (digesters D21C7/00)
D21C3/00 (Pulping cellulose-containing materials) appears on 1,111 US grants and 1,183 published applications in this corpus.
Search patents in D21C- Granted patents
- 1,111
- Published applications
- 1,183
- Assignees
- 603
- Inventors
- 2,330
- Latest grant
- 4 Aug 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 9 | 0 |
| 1977 | 9 | 0 |
| 1978 | 21 | 0 |
| 1979 | 12 | 0 |
| 1980 | 11 | 0 |
| 1981 | 9 | 0 |
| 1982 | 9 | 0 |
| 1983 | 5 | 0 |
| 1984 | 12 | 0 |
| 1985 | 8 | 0 |
| 1986 | 10 | 0 |
| 1987 | 10 | 0 |
| 1988 | 14 | 0 |
| 1989 | 14 | 0 |
| 1990 | 17 | 0 |
| 1991 | 13 | 0 |
| 1992 | 5 | 0 |
| 1993 | 12 | 0 |
| 1994 | 12 | 0 |
| 1995 | 15 | 0 |
| 1996 | 14 | 0 |
| 1997 | 20 | 0 |
| 1998 | 18 | 0 |
| 1999 | 17 | 0 |
| 2000 | 29 | 0 |
| 2001 | 28 | 8 |
| 2002 | 23 | 31 |
| 2003 | 18 | 22 |
| 2004 | 15 | 30 |
| 2005 | 10 | 29 |
| 2006 | 12 | 23 |
| 2007 | 16 | 26 |
| 2008 | 11 | 33 |
| 2009 | 14 | 38 |
| 2010 | 17 | 51 |
| 2011 | 30 | 56 |
| 2012 | 32 | 48 |
| 2013 | 36 | 51 |
| 2014 | 56 | 78 |
| 2015 | 35 | 73 |
| 2016 | 42 | 70 |
| 2017 | 39 | 63 |
| 2018 | 39 | 38 |
| 2019 | 38 | 57 |
| 2020 | 30 | 47 |
| 2021 | 44 | 60 |
| 2022 | 32 | 69 |
| 2023 | 31 | 48 |
| 2024 | 54 | 53 |
| 2025 | 62 | 53 |
| 2026 | 22 | 28 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
- D21C 3/22Pulping cellulose-containing materials: other features of pulping processes565
- D21C 3/02Pulping cellulose-containing materials: with inorganic bases or alkaline reacting compounds387
- D21C 3/04Pulping cellulose-containing materials: with acids, acid salts or acid anhydrides221
- D21C 3/20Pulping cellulose-containing materials: with organic solvents or in solvent environment182
- D21C 3/003Pulping cellulose-containing materials: with organic compounds88
- D21C 3/006Pulping cellulose-containing materials: with compounds not otherwise provided for29
- D21C 3/18Pulping cellulose-containing materials: with halogens or halogen-generating compounds17
Recent patents
- Optimization of chemical consumption in biomass delignification4 Aug 2026US 12,698,589 B2Sixring Inc.
- Processes for fractionation of biomass4 Aug 2026US 12,698,590 B2The Board of Trustees of The University of Alabama
- Approach to biomass delignification28 Jul 2026US 12,692,653 B2Sixring Inc.
- 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
- 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
- Method and system for treating biomass material6 Aug 2026US 2026/0226397 A1Valmet Corporation
- Foam-Based Manufacturing System and Process6 Aug 2026US 2026/0226679 A1Kimberly-Clark Worldwide, Inc.
- Chemical wood pulp with enhanced tensile strength6 Aug 2026US 2026/0226685 A1SöDra SkogsäGarna Ekonomisk FöRening
Most cited
By later US patents
- Lyocell fibers and process for their preparation138US 6,235,392 B1Weyerhaeuser Company · 2001
- Hydrolysis and fractionation of lignocellulosic biomass137US 6,022,419 AMidwest Research Institute · 2000
- Process of pulping and bleaching fibrous plant material with tert-butyl alcohol and tert-butyl peroxide128US 5,252,183 AABB Lummus Crest Inc. · 1993
- Lyocell fibers having enhanced CV properties115US 6,221,487 B1Weyerhauser Company · 2001
- High efficiency organosolv saccharification process109US 4,470,851 A1984