EP0511695B2 - Verfahren zum Bleichen von Lignocellulose enthaltendem Zellstoff - Google Patents

Verfahren zum Bleichen von Lignocellulose enthaltendem Zellstoff Download PDF

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Publication number
EP0511695B2
EP0511695B2 EP92201005A EP92201005A EP0511695B2 EP 0511695 B2 EP0511695 B2 EP 0511695B2 EP 92201005 A EP92201005 A EP 92201005A EP 92201005 A EP92201005 A EP 92201005A EP 0511695 B2 EP0511695 B2 EP 0511695B2
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EP
European Patent Office
Prior art keywords
pulp
magnesium
bleaching
process according
hydrogen peroxide
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP92201005A
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English (en)
French (fr)
Other versions
EP0511695A1 (de
EP0511695B1 (de
Inventor
Lennart Andersson
Jiri Basta
Lillemor Holtinger
Jan Höök
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nouryon Pulp and Performance Chemicals AB
Original Assignee
Eka Chemicals AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
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First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=20382601&utm_source=***_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0511695(B2) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Eka Chemicals AB filed Critical Eka Chemicals AB
Priority to EP94203640A priority Critical patent/EP0679760B1/de
Publication of EP0511695A1 publication Critical patent/EP0511695A1/de
Application granted granted Critical
Publication of EP0511695B1 publication Critical patent/EP0511695B1/de
Publication of EP0511695B2 publication Critical patent/EP0511695B2/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/16—Bleaching ; Apparatus therefor with per compounds
    • D21C9/163—Bleaching ; Apparatus therefor with per compounds with peroxides
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/1005—Pretreatment of the pulp, e.g. degassing the pulp
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/1026—Other features in bleaching processes
    • D21C9/1036—Use of compounds accelerating or improving the efficiency of the processes
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/147—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications
    • D21C9/153—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications with ozone

Definitions

  • the present invention relates to a process for delignification and bleaching of chemically digested lignocellulose-containing pulp.
  • the pulp is bleached at a pH of between about 1 and about 6, whereupon a water-soluble compound containing an alkaline earth metal is added at a pH of between about 1 and about 7 before the pulp is treated with a chlorine-free bleaching agent.
  • the initial acidic treatment removes the trace metals of the pulp, whereas the subsequent addition of alkaline earth metal ions in aqueous solution returns the ions to the positions in the pulp where they have a particularly beneficial effect on the preservation of the cellulose chains and, consequently, on the viscosity, as well as on the consumption of bleaching agent in the subsequent bleaching step.
  • the pulp may be finally bleached to the desired brightness, suitably with a chlorine-free bleaching agent, such a ozone, to completely avoid formation and discharge of AOX.
  • chlorine-free bleaching agents such as hydrogen peroxide, peracetic acid or ozone
  • the delignification and consumption of the bleaching agent become less effective than with chlorine-containing bleaching agents, unless the pulp is pretreated.
  • a hydrogen peroxide treatment in an alkaline environment is disturbed by the presence in the pulp of ions of certain metals, such as Mn, Cu and Fe. These metal ions cause degradation of hydrogen peroxide, thereby reducing the efficiency of the peroxide treatment and increasing the consumption of peroxide.
  • this can be counteracted by pretreating the pulp with an acid, such as sulphuric acid or nitric acid, whereby the concentration of all types of metal ions is reduced.
  • an acid such as sulphuric acid or nitric acid
  • metal ions for example Mg, which are advantageous to the peroxide treatment disappear, which ions stabilize the peroxide and increase the selectivity of the peroxide.
  • CA-A-575,636 discloses the addition of magnesium sulphate to stabilize alkaline peroxide solutions. However, the addition is made directly to the bleaching liquor and in alkaline environment insoluble magnesium hydroxide precipitates. Furthermore, US-A-4,222,819 discloses the addition of magnesium ions to acidic peroxide solutions, but also in this case the addition is made directly to the bleaching liquor. None of the related methods makes possible diffusion of the magnesium ions into the pulp to such an extent, that a pulp of high brightness and strength can be obtained.
  • US-A-3,507,744 relates to a bleaching process for wood pulp, where the pulp is contacted with an alkaline solution containing hydrogen peroxide and further a pyrophosphate to stabilize the peroxide. The aim of the process is to attain high brightness in a single bleaching step without a substantial loss in yield. The process can be preceded by a pretreatment in one or more steps, for example acid treatment and/or addition of barium or calcium salts.
  • the invention provides a process in which lignocellulose-containing pulp is treated under the conditions disclosed in the claims, whereby the metal ions harmful to the subsequent bleaching are effectively removed and the profile of alkaline earth metals is restored before the pulp is bleached in a chlorine-free bleaching step.
  • Acid treatment is an effective process to eliminate metal ions from lignocellulose-containing pulps.
  • ions of alkaline earth metals especially when in their original positions in the pulp, have a positive influence on the selectivity of the delignification as well as on the stability and consumption of chlorine-free bleaching agents, such as peroxides, ozone and oxygen.
  • the present process presents an economic solution to the problem of creating a suitable trace-metal profile for the subsequent chlorine-free bleaching, in that non-desirable metal ions are eliminated while supplied ions of magnesium essentially recover the positions in the vicinity of the cellulose chains previously occupied by ions of alkaline earth metals.
  • Compounds containing magnesium relate to water-soluble chemicals containing magnesium or mixtures of water-soluble chemicals containing magnesium and calcium.
  • Use is suitably made of magnesium-containing compounds such as magnesium sulphate or magnesium chloride, or calcium-containing compounds such as calcium chloride or calcium oxide.
  • Use is preferably made of magnesium sulphate or magnesium chloride, the use of magnesium sulphate being especially preferred.
  • the combination of temperature and pH at the addition of the compound containing magnesium is always so chosen that the compound is in aqueous solution when contacted with the pulp.
  • the acid bleaching step is carried out at a pH of from about 1 up to about 6, suitably from 1.5 up to 5, preferably from 2 up to 4. It is especially preferred that the acid bleaching step is carried out at a pH of from 2 up to 3.
  • the magnesium addition is made at a pH in the range from about 1 up to about 7, suitably in the range from 2 up to 6, preferably in the range from 2 up to 4. It is especially preferred that the addition of magnesium is made at a pH of from 2 up to 3.
  • the chlorine-free bleaching agent is hydrogen peroxide and the pulp is treated at a pH of from about 8 up to about 12, preferably at a pH of from 10 up to 12. Treatment with the other chlorine-free bleaching agents mentioned above, is carried out within the normal pH ranges for each bleaching agent, which are well-known to the person skilled in the art.
  • the treatment according to the invention is carried out with a washing step between the acid bleaching step and the addition of magnesium ions, such that the trace metals that are harmful to the treatment with a chlorine-free bleaching agent are removed from the pulp suspension.
  • Bleaching and/or delignifying chemicals active within the pH range suitable in the acid treatment are chlorine dioxide, ozone, peracetic acid and/or an acid peroxide-containing compound.
  • a combination of acid treatment and bleaching and/or delignifying treatment takes place in an ozone step.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Polysaccharides And Polysaccharide Derivatives (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Processes Of Treating Macromolecular Substances (AREA)
  • Agricultural Chemicals And Associated Chemicals (AREA)
  • Stringed Musical Instruments (AREA)
  • Diaphragms For Electromechanical Transducers (AREA)
  • Breeding Of Plants And Reproduction By Means Of Culturing (AREA)
  • Investigating Or Analysing Biological Materials (AREA)
  • Materials For Medical Uses (AREA)
  • Noodles (AREA)

Claims (10)

  1. Verfahren zum Entholzen und Bleichen von chemisch aufgeschlossenem lignocellulosehaltigem Zellstoff, dadurch gekennzeichnet. daß der Zellstoff bei einem pH-Wert im Bereich von etwa 1 bis etwa 6 mit einer aus Chlordioxid, Ozon. Peressigsäure und Säureperoxiden ausgewählten Bleichchemikalie gebleicht wird, wonach der Zellstoff gewaschen wird, worauf eine Magnesium enthaltende wasserlösliche Chemikalie bei einem pH-Wert im Bereich von etwa 1 bis etwa 7 während etwa 20 bis etwa 180 Min. und in einer Menge von etwa 0.01 bis etwa 10 kg/Tonne trockener Zellstoff, berechnet als Magnesium, zugegeben wird, und daß der Zellstoff anschließend bei einem pH-Wert von etwa 8 bis etwa 12 mit Wasserstoffperoxid gebleicht wird.
  2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der Zellstoff anschließend bei einem pH-Wert von 10 bis 12 mit Wasserstoffperoxid gebleicht wird.
  3. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der chemisch aufgeschlossene Zellstoff Sulfatzellstoff ist.
  4. Verfahren nach Anspruch 1. dadurch gekennzeichnet, daß die Magnesium enthaltende wasserlösliche Chemikalie bei einem pH-Wert von 2 bis 6 zugegeben wird.
  5. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Magnesium enthaltende wasserlösliche Chemikalie ein Gemisch aus magnesiumhaltigen und calciumhaltigen Verbindungen ist.
  6. Verfahren nach Anspruch 1 oder 5, dadurch gekennzeichnet, daß die Magnesium enthaltende wasserlösliche Chemikalie aus Magnesiumsulfat oder Magnesiumchlorid besteht.
  7. Verfahren nach Anspruch 5, dadurch gekennzeichnet, daß die Calcium enthaltende wasserlösliche Chemikalie aus Calciumchlorid oder Calciumoxid besteht.
  8. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß das Bleichen vor der Zugabe einer Magnesium enthaltenden wasserlöslichen Chemikalie bei einem pH-Wert im Bereich von 1.5 bis 5 durchgeführt wird.
  9. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der Zellstoff schließlich in einem oder mehreren Schritten mit Ozon gebleicht wird.
  10. Verfahren nach den Ansprüchen 1-9, dadurch gekennzeichnet, daß der Schritt der bleichung bei einer Temperatur von etwa 10 bis etwa 95°C während etwa 1 bis etwa 120 Min. durchgeführt wird, daß die Magnesium enthaltende wasserlösliche Chemikalie bei einer Temperatur von etwa 10 bis 95°C während etwa 20 bis etwa 180 Min. und in einer Menge von 0.5 bis 5 kg/Tonne trockener Zellstoff, berechnet als Magnesium, zugegeben wird, wobei der behandelte Zellstoff eine Konzentration von etwa 3 bis etwa 35 Gew.-% hat.
EP92201005A 1991-04-30 1992-04-08 Verfahren zum Bleichen von Lignocellulose enthaltendem Zellstoff Expired - Lifetime EP0511695B2 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP94203640A EP0679760B1 (de) 1991-04-30 1992-04-08 Verfahren zum Bleichen von Lignocellulose-enthaltendem Zellstoff

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9101301 1991-04-30
SE9101301A SE470065C (sv) 1991-04-30 1991-04-30 Behandling av kemisk massa med en syra och därefter en magnesium- och kalciumförening vid klorfri blekning

Related Child Applications (2)

Application Number Title Priority Date Filing Date
EP94203640.1 Division-Into 1992-04-08
EP94203640A Division EP0679760B1 (de) 1991-04-30 1992-04-08 Verfahren zum Bleichen von Lignocellulose-enthaltendem Zellstoff

Publications (3)

Publication Number Publication Date
EP0511695A1 EP0511695A1 (de) 1992-11-04
EP0511695B1 EP0511695B1 (de) 1996-08-28
EP0511695B2 true EP0511695B2 (de) 2004-06-02

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Family Applications (2)

Application Number Title Priority Date Filing Date
EP92201005A Expired - Lifetime EP0511695B2 (de) 1991-04-30 1992-04-08 Verfahren zum Bleichen von Lignocellulose enthaltendem Zellstoff
EP94203640A Expired - Lifetime EP0679760B1 (de) 1991-04-30 1992-04-08 Verfahren zum Bleichen von Lignocellulose-enthaltendem Zellstoff

Family Applications After (1)

Application Number Title Priority Date Filing Date
EP94203640A Expired - Lifetime EP0679760B1 (de) 1991-04-30 1992-04-08 Verfahren zum Bleichen von Lignocellulose-enthaltendem Zellstoff

Country Status (14)

Country Link
EP (2) EP0511695B2 (de)
JP (1) JP2592747B2 (de)
AT (2) ATE141971T1 (de)
BR (1) BR9201554A (de)
CA (1) CA2067296C (de)
DE (2) DE69227640T2 (de)
ES (1) ES2091395T3 (de)
FI (1) FI111964B (de)
MX (1) MX9201966A (de)
NO (1) NO180495C (de)
NZ (1) NZ242465A (de)
RU (1) RU2039141C1 (de)
SE (1) SE470065C (de)
ZA (1) ZA923073B (de)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8778136B2 (en) 2009-05-28 2014-07-15 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US9511167B2 (en) 2009-05-28 2016-12-06 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US9512563B2 (en) 2009-05-28 2016-12-06 Gp Cellulose Gmbh Surface treated modified cellulose from chemical kraft fiber and methods of making and using same
US9512237B2 (en) 2009-05-28 2016-12-06 Gp Cellulose Gmbh Method for inhibiting the growth of microbes with a modified cellulose fiber
US10000890B2 (en) 2012-01-12 2018-06-19 Gp Cellulose Gmbh Low viscosity kraft fiber having reduced yellowing properties and methods of making and using the same
US10138598B2 (en) 2013-03-14 2018-11-27 Gp Cellulose Gmbh Method of making a highly functional, low viscosity kraft fiber using an acidic bleaching sequence and a fiber made by the process
US10151064B2 (en) 2013-02-08 2018-12-11 Gp Cellulose Gmbh Softwood kraft fiber having an improved α-cellulose content and its use in the production of chemical cellulose products
US10174455B2 (en) 2013-03-15 2019-01-08 Gp Cellulose Gmbh Low viscosity kraft fiber having an enhanced carboxyl content and methods of making and using the same
US10294613B2 (en) 2011-05-23 2019-05-21 Gp Cellulose Gmbh Softwood kraft fiber having improved whiteness and brightness and methods of making and using the same technical field

Families Citing this family (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI89516B (fi) 1989-05-10 1993-06-30 Ahlstroem Oy Foerfarande foer blekning av cellulosamassa med otson
US6398908B1 (en) 1991-04-30 2002-06-04 Eka Nobel Ab Process for acid bleaching of lignocellulose-containing pulp with a magnesium compound
SE500353C2 (sv) * 1992-10-26 1994-06-06 Sca Wifsta Oestrand Ab Peroxidblekning av sulfatmassa med tillsats av magnesium före blekningen
SE512137C2 (sv) * 1992-10-29 2000-01-31 Eka Chemicals Ab Förfarande för blekning av lignocellulosahaltig massa
SE9203366L (sv) * 1992-11-11 1994-05-12 Mo Och Domsjoe Ab Förfarande vid delignifiering och/eller blekning av cellulosamassa
US6007678A (en) * 1992-11-27 1999-12-28 Eka Nobel Ab Process for delignification of lignocellulose-containing pulp with an organic peracid or salts thereof
ATE184060T1 (de) * 1993-04-20 1999-09-15 Eka Chemicals Ab Verfahren zum bleichen von lignozellulose- enthaltendem zellstoff
SE9301960L (sv) * 1993-06-08 1994-07-25 Kvaerner Pulping Tech Blekning av kemisk massa med peroxid vid övertryck
US6605181B1 (en) * 1993-10-01 2003-08-12 Kvaerner Pulping Aktiebolag Peroxide bleach sequence including an acidic bleach stage and including a wash stage
BE1007757A3 (fr) * 1993-11-10 1995-10-17 Solvay Interox Procede pour le blanchiment d'une pate a papier chimique.
US6776876B1 (en) 1994-10-13 2004-08-17 Andritz Oy Method of treating cellulosic pulp to remove hexenuronic acid
FI102301B1 (fi) * 1994-10-13 1998-11-13 Ahlstrom Machinery Oy Menetelmä selluloosamassojen käsittelemiseksi
DE19516151A1 (de) 1995-05-03 1996-11-07 Sven Siegle Verfahren zur Herstellung einer Pulpe aus zellulosehaltigem Material, die Pulpe selbst und deren Verwendung
FI105701B (fi) 1995-10-20 2000-09-29 Ahlstrom Machinery Oy Menetelmä ja laitteisto massan käsittelemiseksi
JPH108092A (ja) * 1996-06-21 1998-01-13 Mitsubishi Paper Mills Ltd 過酸化物漂白用安定化剤及びそれを用いた繊維系物質の漂白方法
BE1010679A3 (fr) * 1996-10-11 1998-11-03 Solvay Interox Procede de delignification et de blanchiment de pate a papier chimique.
ID23571A (id) * 1997-08-25 2000-05-04 Praxair Technology Inc Metoda penerapan ozon dalam pemutihan ecf
JP2002266272A (ja) * 2001-03-12 2002-09-18 Nippon Paper Industries Co Ltd セルロース質繊維材料パルプの漂白方法
US6743332B2 (en) * 2001-05-16 2004-06-01 Weyerhaeuser Company High temperature peroxide bleaching of mechanical pulps
KR100547491B1 (ko) * 2005-04-27 2006-01-31 이권혁 대나무를 이용하여 생산하는 섬유용 펄프의 제조방법 및 그 펄프
RU2636306C2 (ru) 2012-04-18 2017-11-21 ДжиПи СЕЛЛЬЮЛОУС ГМБХ Использование поверхностно-активного вещества для обработки пульпы и улучшение введения крафт-пульпы в волокно для получения вискозы и других вторичных волокнистых продуктов
BR112015006593B1 (pt) * 2012-09-27 2022-07-12 Andritz Inc. Processo químico mecânico de formação de polpa
CA2989264A1 (en) * 2015-09-30 2017-04-06 Imerys Minerals Limited Methods for bleaching aqueous pulps and compositions for use in these methods
US10865519B2 (en) 2016-11-16 2020-12-15 Gp Cellulose Gmbh Modified cellulose from chemical fiber and methods of making and using the same
WO2021209586A1 (en) * 2020-04-16 2021-10-21 Bim Kemi Ab Delignification process

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US3507744A (en) * 1966-04-01 1970-04-21 Kimberly Clark Co Wood pulp bleaching process utilizing peroxide pyrophosphate high concentration compositions
SE335053B (de) * 1969-05-13 1971-05-10 Mo Och Domsjoe Ab
DE2742262C2 (de) * 1977-09-20 1982-06-09 Degussa Ag, 6000 Frankfurt Verfahren zur Herstellung eines mittel- bis hochviskosen Nadelholz-Sulfitzellstoffs
FR2520397A1 (fr) * 1982-01-28 1983-07-29 Centre Tech Ind Papier Procede pour le traitement de pates papetieres chimiques
FR2557605B1 (fr) * 1983-12-29 1987-12-11 Atochem Procede de blanchiment de pates papetieres par le peroxyde d'hydrogene
JPH0364589A (ja) * 1989-07-28 1991-03-19 Mitsubishi Gas Chem Co Inc 化学パルプの漂白方法

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9970158B2 (en) 2009-05-28 2018-05-15 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US8778136B2 (en) 2009-05-28 2014-07-15 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US9512561B2 (en) 2009-05-28 2016-12-06 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US9512563B2 (en) 2009-05-28 2016-12-06 Gp Cellulose Gmbh Surface treated modified cellulose from chemical kraft fiber and methods of making and using same
US9512237B2 (en) 2009-05-28 2016-12-06 Gp Cellulose Gmbh Method for inhibiting the growth of microbes with a modified cellulose fiber
US9512562B2 (en) 2009-05-28 2016-12-06 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US9511167B2 (en) 2009-05-28 2016-12-06 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US10106927B2 (en) 2009-05-28 2018-10-23 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US10294613B2 (en) 2011-05-23 2019-05-21 Gp Cellulose Gmbh Softwood kraft fiber having improved whiteness and brightness and methods of making and using the same technical field
US10000890B2 (en) 2012-01-12 2018-06-19 Gp Cellulose Gmbh Low viscosity kraft fiber having reduced yellowing properties and methods of making and using the same
US10151064B2 (en) 2013-02-08 2018-12-11 Gp Cellulose Gmbh Softwood kraft fiber having an improved α-cellulose content and its use in the production of chemical cellulose products
US10138598B2 (en) 2013-03-14 2018-11-27 Gp Cellulose Gmbh Method of making a highly functional, low viscosity kraft fiber using an acidic bleaching sequence and a fiber made by the process
US10174455B2 (en) 2013-03-15 2019-01-08 Gp Cellulose Gmbh Low viscosity kraft fiber having an enhanced carboxyl content and methods of making and using the same
US10294614B2 (en) 2013-03-15 2019-05-21 Gp Cellulose Gmbh Low viscosity kraft fiber having an enhanced carboxyl content and methods of making and using the same

Also Published As

Publication number Publication date
EP0511695A1 (de) 1992-11-04
ES2091395T3 (es) 1996-11-01
RU2039141C1 (ru) 1995-07-09
SE470065C (sv) 1996-01-15
EP0679760B1 (de) 1998-11-18
SE470065B (sv) 1993-11-01
JPH05148784A (ja) 1993-06-15
DE69213080D1 (de) 1996-10-02
JP2592747B2 (ja) 1997-03-19
SE9101301L (sv) 1992-10-31
EP0679760A1 (de) 1995-11-02
FI921886A0 (fi) 1992-04-27
NZ242465A (en) 1993-12-23
CA2067296C (en) 1997-03-04
AU651192B2 (en) 1994-07-14
ZA923073B (en) 1992-12-30
NO180495C (no) 2003-06-06
CA2067296A1 (en) 1992-10-31
ATE173518T1 (de) 1998-12-15
SE9101301D0 (sv) 1991-04-30
NO921671D0 (no) 1992-04-29
MX9201966A (es) 1992-11-01
AU1514992A (en) 1993-03-11
BR9201554A (pt) 1992-12-01
ATE141971T1 (de) 1996-09-15
DE69227640D1 (de) 1998-12-24
NO921671L (no) 1992-11-02
DE69227640T2 (de) 1999-05-06
FI921886A (fi) 1992-10-31
NO180495B (no) 1997-01-20
FI111964B (fi) 2003-10-15
EP0511695B1 (de) 1996-08-28

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