D21D
Treatment of the materials before passing to the paper-making machine
D21D (Treatment of the materials before passing to the paper-making machine) appears on 1,557 US grants and 901 published applications in this corpus.
Search patents in D21D- Granted patents
- 1,557
- Published applications
- 901
- Assignees
- 459
- Inventors
- 1,861
- Latest grant
- 6 Oct 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 17 | 0 |
| 1977 | 13 | 0 |
| 1978 | 17 | 0 |
| 1979 | 19 | 0 |
| 1980 | 30 | 0 |
| 1981 | 36 | 0 |
| 1982 | 18 | 0 |
| 1983 | 23 | 0 |
| 1984 | 28 | 0 |
| 1985 | 29 | 0 |
| 1986 | 30 | 0 |
| 1987 | 43 | 0 |
| 1988 | 23 | 0 |
| 1989 | 27 | 0 |
| 1990 | 42 | 0 |
| 1991 | 54 | 0 |
| 1992 | 45 | 0 |
| 1993 | 54 | 0 |
| 1994 | 32 | 0 |
| 1995 | 40 | 0 |
| 1996 | 37 | 0 |
| 1997 | 47 | 0 |
| 1998 | 48 | 0 |
| 1999 | 43 | 0 |
| 2000 | 43 | 0 |
| 2001 | 34 | 19 |
| 2002 | 36 | 26 |
| 2003 | 38 | 30 |
| 2004 | 18 | 43 |
| 2005 | 27 | 36 |
| 2006 | 19 | 39 |
| 2007 | 25 | 41 |
| 2008 | 23 | 30 |
| 2009 | 17 | 28 |
| 2010 | 29 | 31 |
| 2011 | 25 | 25 |
| 2012 | 29 | 30 |
| 2013 | 19 | 30 |
| 2014 | 27 | 35 |
| 2015 | 29 | 38 |
| 2016 | 18 | 27 |
| 2017 | 21 | 32 |
| 2018 | 21 | 31 |
| 2019 | 27 | 49 |
| 2020 | 30 | 51 |
| 2021 | 36 | 48 |
| 2022 | 34 | 47 |
| 2023 | 41 | 40 |
| 2024 | 43 | 47 |
| 2025 | 35 | 28 |
| 2026 | 18 | 20 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Main groups
Granted patents with any code in the group
Recent patents
- Method for fractionation of highly refined cellulose6 Oct 2026US 12,753,551 B2Stora Enso OYJ
- Refiner filling piece having multiple coatings on bars22 Sep 2026US 12,742,288 B2Aikawa Fiber Technologies Oy
- Blade for a refiner for refining lignocellulosic material, and refiner comprising at least one blade4 Aug 2026US 12,698,591 B2Valmet Corporation
- System and method for fiber cleaning, alignment, and sizing30 Jun 2026US 12,668,919 B1
- Accept tank mixing arrangement30 Jun 2026US 12,668,920 B2Andritz Inc.
- Blade for a refiner for refining lignocellulosic material, and refiner comprising at least one blade1 Oct 2026US 2026/0297848 A1Valmet Corporation
- Method and plant for dense pulp refining for papermaking17 Sep 2026US 2026/0275633 A1
- Process for producing a fibrous material27 Aug 2026US 2026/0250912 A1Stora Enso OYJ
- Method, system and program for producing a refiner segment out of a worn refiner segment, and a rebuilt refiner segment20 Aug 2026US 2026/0241456 A1Valmet Corporation
- Production of ctmp from a hardwood/softwood mixture23 Jul 2026US 2026/0210039 A1Billerud Aktiebolag (publ)
Most cited
By later US patents
- Super microfibrillated cellulose, process for producing the same, and coated paper and tinted paper using the same136US 6,183,596 B2Tokushu Paper Mfg. Co., Ltd. · 2001
- Apparatus for fluidizing, degassing and pumping a suspension of fibrous cellulose material130US 5,209,641 AKamyr, Inc. · 1993
- System and method for producing bonded fiber/cellulose products111US 8,795,470 B22014
- Super microfibrillated cellulose, process for producing the same, and coated paper and tinted paper using the same110US 6,214,163 B1Tokushu Paper Mfg. Co., Ltd. · 2001
- Method and apparatus for manufacturing microfibrillated cellulose fiber109US 7,381,294 B2Japan Absorbent Technology Institute · 2008