D21C 1/00
Pretreatment of the finely-divided materials before digesting
Official title: Pretreatment of the finely-divided materials before digesting (of waste paper D21C5/02)
D21C1/00 (Pretreatment of the finely-divided materials before digesting) appears on 530 US grants and 595 published applications in this corpus.
Search patents in D21C- Granted patents
- 530
- Published applications
- 595
- Assignees
- 344
- Inventors
- 1,218
- Latest grant
- 6 Oct 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 1 | 0 |
| 1977 | 3 | 0 |
| 1978 | 14 | 0 |
| 1979 | 3 | 0 |
| 1980 | 2 | 0 |
| 1981 | 1 | 0 |
| 1982 | 2 | 0 |
| 1983 | 1 | 0 |
| 1984 | 5 | 0 |
| 1985 | 3 | 0 |
| 1986 | 3 | 0 |
| 1987 | 1 | 0 |
| 1988 | 5 | 0 |
| 1989 | 2 | 0 |
| 1990 | 2 | 0 |
| 1991 | 3 | 0 |
| 1992 | 3 | 0 |
| 1993 | 8 | 0 |
| 1994 | 7 | 0 |
| 1995 | 8 | 0 |
| 1996 | 7 | 0 |
| 1997 | 9 | 0 |
| 1998 | 9 | 0 |
| 1999 | 5 | 0 |
| 2000 | 10 | 0 |
| 2001 | 16 | 3 |
| 2002 | 12 | 12 |
| 2003 | 8 | 5 |
| 2004 | 4 | 9 |
| 2005 | 3 | 8 |
| 2006 | 1 | 9 |
| 2007 | 4 | 11 |
| 2008 | 3 | 13 |
| 2009 | 5 | 19 |
| 2010 | 6 | 21 |
| 2011 | 14 | 29 |
| 2012 | 14 | 32 |
| 2013 | 14 | 29 |
| 2014 | 19 | 32 |
| 2015 | 28 | 35 |
| 2016 | 29 | 32 |
| 2017 | 20 | 34 |
| 2018 | 24 | 30 |
| 2019 | 24 | 31 |
| 2020 | 20 | 29 |
| 2021 | 28 | 43 |
| 2022 | 18 | 35 |
| 2023 | 19 | 32 |
| 2024 | 34 | 26 |
| 2025 | 31 | 21 |
| 2026 | 15 | 15 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
- D21C 1/02Pretreatment of the finely-divided materials before digesting: with water or steam216
- D21C 1/04Pretreatment of the finely-divided materials before digesting: with acid reacting compounds134
- D21C 1/06Pretreatment of the finely-divided materials before digesting: with alkaline reacting compounds96
- D21C 1/10Physical methods for facilitating impregnation68
- D21C 1/08Pretreatment of the finely-divided materials before digesting: with oxygen-generating compounds17
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- Method and system for treating biomass material6 Aug 2026US 2026/0226397 A1Valmet Corporation
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Most cited
By later US patents
- Method for increasing the accessibility of cellulose in lignocellulosic materials, particularly hardwoods agricultural residues and the like177US 4,461,648 A1984
- Prehydrolysis of lignocellulose148US 5,424,417 AMidwest Research Institute · 1995
- Prehydrolysis of lignocellulose126US 5,705,369 AMidwest Research Institute · 1998
- Method of treating lignocellulosic biomass to produce cellulose109US 6,419,788 B1PureVision Technology, Inc. · 2002
- Process for oxygen pulping of lignocellulosic material and recorvery of pulping chemicals96US 6,770,168 B1Kiram AB · 2004