WO1995035408A1 - Delignification d'une pate chimique avec un peroxyde en presence d'un metal de transition - Google Patents

Delignification d'une pate chimique avec un peroxyde en presence d'un metal de transition Download PDF

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Publication number
WO1995035408A1
WO1995035408A1 PCT/FI1995/000353 FI9500353W WO9535408A1 WO 1995035408 A1 WO1995035408 A1 WO 1995035408A1 FI 9500353 W FI9500353 W FI 9500353W WO 9535408 A1 WO9535408 A1 WO 9535408A1
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WO
WIPO (PCT)
Prior art keywords
peroxide
pulp
peracid
treatment
delignification
Prior art date
Application number
PCT/FI1995/000353
Other languages
English (en)
Inventor
Aarto Paren
Jukka JÄKÄRÄ
Juha Patola
Original Assignee
Kemira Chemicals Oy
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
Application filed by Kemira Chemicals Oy filed Critical Kemira Chemicals Oy
Priority to AU27400/95A priority Critical patent/AU2740095A/en
Publication of WO1995035408A1 publication Critical patent/WO1995035408A1/fr

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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
    • 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
    • D21C9/1026—Other features in bleaching processes
    • D21C9/1042—Use of chelating agents

Definitions

  • the bleaching chemical used has conventionally been chlorine, by means of which an effective bleaching is achieved and the quality of the paper obtained is high.
  • chlorine a compound that has been used for treating a wide range of bleaching conditions.
  • other bleaching chemi ⁇ cals such as chlorine dioxide, oxygen, ozone, peroxides, and peracids.
  • the overall objective has been to shift to bleaching which is completely free of chlorine chemicals in order to avoid the environmental hazards caused by chlorine chemicals, and chlorine residues in completed paper.
  • the bleaching process usually comprises a bleaching sequence made up of successive treatment steps, wherein oxidative steps which decompose lignin and alkaline washing steps alternate.
  • oxidative steps which decompose lignin and alkaline washing steps alternate.
  • a pulp has been ob ⁇ tained which in its brightness, 83-87 % ISO, and in its strength is not of the level of pulp bleached with chlorine chemicals.
  • ozone has been used as the oxidant, a bright ⁇ ness above 88 % ISO has been achieved, but there has been the problem of the proneness of the process to disturbances.
  • a chemical pulp contains, in a water-insoluble form, heavy metals derived from the wood raw material, mainly iron, man ⁇ ganese and copper, which catalyze the decomposition of the peroxide and the peracid used as oxidants and thereby increase the consumption of these chemicals in bleaching. These decom ⁇ position reactions also have a detrimental effect on the quali ⁇ ty of pulp obtained by peroxide bleaching.
  • the invention is characterized in that, before a peroxide and/or peracid treatment activated with an above-mentioned transition metal, the pulp is chelated in order to eliminate any heavy metals, such as iron, manganese and/or copper, derived from the wood raw material.
  • the chelation takes place directly before the ac ⁇ tivated delignification step, whereby the situation is avoided that heavy metals released in the bleaching step/steps between the removal of heavy metals and the activated delignification would pass into the activated peroxide and/or peracid step.
  • the bleaching according to the invention comprising chelating and an activated peroxide and/or peracid treatment, to obtain, without chlorine chemicals, a strong, completely white pulp with a brightness above 88 % ISO.
  • the bleaching can be performed without chlorine chemicals or ozone, although the chelating according to the invention, pre- ceding the peroxide and/or peracid step, is also advantageous in a bleaching sequence which comprises chlorine chemical or ozone treatment steps.
  • the invention decreases the consumption of peroxide and/or peracid and enables the metal used as an activator to be efficiently recycled.
  • the invention is suitable for all different chemical pulps, such as softwood and hardwood sulfate pulps, sulfite pulps, semialkaline pulps, and organo- solv pulps. Furthermore, the invention can be exploited in pulping processes, in particular organosolv cooking, such as milox.
  • chela ⁇ tion constitutes a treatment step directly preceding the ac ⁇ tivated peroxide and/or peracid treatment.
  • the chelation can, for example, be performed within an acid pH range before the peroxide and/or peracid treatment, the pH of which is within the range 2-7, preferably 4.5-5.5, and temperature within the range 30-120 °C, preferably approx. 80-100 °C.
  • the advantage here is that it is not necessary to adjust the pH of the pulp between the successive treatment steps in the sequence.
  • the pH of the chelating step is not in itself crit ⁇ ical, and, when necessary, it can be adjusted by means of, for example, sulfuric acid, sulfur oxide, or organic acids.
  • the pulp is subjected to two chelating treatments, in which case the treat ⁇ ment steps succeed one another in the bleaching sequence, in the following order: chelation, activated peroxide and/or per ⁇ acid treatment, chelation and alkaline peroxide treatment.
  • the second chelating step removes from the pulp any residual acti ⁇ vator metal, such as molybdenum, the presence of which in the alkaline peroxide treatment step would be detrimental.
  • the chelation at the same time removes any heavy-metal residues possibly detached from the pulp by the activated peroxide or peracid delignification.
  • the chelating chemical may be DTPA (diethylenetriaminepenta- acetic acid) , which can be used in the form of a commercial 40 % Na salt solution.
  • a suitable amount of the chemical is 0.5-5 kg of DTPA calculated as 100 % chemical per one metric ton of pulp.
  • the acting time of the chelating chemical may be, for example, 15 min - 4 h and the temperature 30-120 °C, pref ⁇ erably 40-90 °C.
  • DTPA was used with good results in the embodi ⁇ ment examples described below.
  • EDTA ethylenediaminetetraacetic acid
  • organic acids phosphonic acid derivatives such as DTMPA, 8-hydroxy- quinoline, ammoniumthiocyanate, quaternary ammonium compounds, etc.
  • a suitable peroxide is hydrogen per ⁇ oxide, and especially suitable peracids include peracetic acid and performic acid.
  • the metal used as the activator i the peroxide and/or peracid step is preferably molybdenum, which can be used as a suitable compound, for example as a Na molybdenate solution, which is fed into the pulp separate from the feed of the peroxide and/or peracid.
  • molybdenum which can be used as a suitable compound, for example as a Na molybdenate solution, which is fed into the pulp separate from the feed of the peroxide and/or peracid.
  • vanadium and tungsten were used in addition to molybdenum, with good results. It is, however, clear that any transition metals of the above- mentioned groups, known per se, which activate peroxide or peracid delignification, can be used in the invention.
  • silicon and/or phos ⁇ phorus compounds may be used as additives promoting peroxide or peracid delignification. It is thus possible to feed into the pulp, for example, sodium silicate and/or sodium phosphate in the same solution as molybdenum or other such activator metal.
  • the silica or phosphorus may also belong to the same compound as the activator metal, one example being compounds of the silicomolybdenic acid type.
  • the following embodiment examples include experiment series in which the effect of the various parameters of bleaching on the results obtained was investigated.
  • Experiments 1 and 2 were performed on unchelated softwood sul ⁇ fate pulp after an oxygen step, and Experiment 3, respectively, on chelate-treated and washed pulp.
  • Experiment 3 consumed con ⁇ siderably more peroxide than did Experiment 1 or 2.
  • Said acti ⁇ vated peroxide steps were performed at 90 °C.
  • An activated peroxide step at 100 °C yielded similar results.
  • An activated peroxide step (mP) after a chelating step consumed considerably less peroxide and gave a more selective delignification than did a corresponding activated step before which chelate treat ⁇ ment and wash had not been carried out (compare Experiments 4 and 5 or 4 and 6) .
  • an oxygen-delignified softwood sulfate pulp was used the heavy metal content of which was quite low.
  • a sulfate pulp may, however, have considerably higher heavy-metal concentrations.
  • a hardwood sulfate pulp may have heavy-metal concentrations considerably higher than those shown in the table.
  • the raw material used was a softwood sulfate pulp in which the Fe and Mn concentrations after oxygen delignification were 18 ppm Fe and 87 ppm Mn.
  • An activated peroxide step without a preceding chelate treatment and wash consumed the entire portion of 20 kg H2 ⁇ 2/t, whereas an mP step after a chelate treatment and a wash consumed peroxide in an amount of 11.5 kg H 2 0 2 /t.
  • the selectivity of the deligni- fication of the activated peroxide step was considerably higher than that of the reference (Experiment No. 7).
  • Molybdenum-activated peracetic acid/peroxide delignification gives a better final result than does molybdenum-activated peroxide delignification, as shown by a comparison of Experi ⁇ ments 1 and 2 in Table 3.
  • Silicate-modified molybdenum- activated peracetic acid/peroxide delignification (Experiment No. 9) gives an even better result than do those mentioned above.
  • the use of phosphorus instead of silicate gives a result almost equally good, as shown by a comparison of Experiments 6 and 8.
  • Raising of the temperature increases the efficacy of silicate- modified molybdenum-activated peracetic acid/peroxide deligni ⁇ fication (compare Experiments 9 and 10).
  • a raising of the tem ⁇ perature and/or an increasing of the reaction time also inten ⁇ sifies the other delignification processes concerned, as shown by a comparison of Experiments 11 and 12, as well as 1.
  • a softwood sulfate pulp was subjected to oxygen delignifica ⁇ tion, a chelating step by using 1 kg of DTPA/metric ton of pulp, and an alkaline oxygen-promoted peroxide delignification.
  • the kappa number of the obtained pulp was 9.7, brightness
  • the pulp obtained in Experiment 11 was subsequently subjected to an alkaline peroxide treatment by using H2O2 at a rate of 20 kg /metric ton at 80 °C for 240 min, the initial pH being 10.6, without a preceding chelating step (Experiments 111 and 112), and with a preceding chelating step (2 kg DTPA/t) (Ex ⁇ periment 113) for 30 min at 70 °C, the initial pH being 5.5.
  • the results are shown in the following Table 3a.
  • Table 3 shows examples of the effect of various reaction condi ⁇ tions on silicomolybdenym-activated peroxide delignification.
  • a high temperature (compare Experiments 4, 5 and 6) , a high consistency (compare Experiments 5 and 10), and a long reaction time (compare Experiments 8, 5 and 9) improve the efficacy of delignification.
  • the said chelating step also "washes" away molybdenum of the activation step or corresponding catalyst. Molybdenum present in alkaline peroxide bleaching increases the consumption of peroxide, as can be seen in Table 3b. Table 3b
  • a softwood sulfate pulp was subjected to peroxide-promoted oxygen delignification and a chelating step by using 2 kg of
  • Pulps 1, 2, 3, 4 and 6 of Table 4 were subsequently subjected to a chelating step and the chloride-oxide delignified pulp No. 5 was subjected to an alkali(E) step.
  • the washed pulps 1, 2, 3, 4 and 6 were further subjected to an alkaline peroxide treat ⁇ ment and respectively pulp 5, after an alkali and washing step, to a chlorine dioxide (D) step.
  • the bleaching experiments of Table 4a were continued on from the experiments correspondingly numbered in Table 4.
  • a softwood sulfate pulp was subjected to peroxide-promoted oxygen delignification and to a chelating step in which DTPA was used at a rate of 2 kg/one metric ton of pulp.
  • the kappa number of the obtained pulp was 7.7, brightness 55.8 % ISO, and viscosity 800 dm /kg.
  • the results of peroxide and peroxide/- peracid delignification steps, activated with various metals, performed on this pulp are shown in Table 5.
  • Mo-activated peroxide delignifica ⁇ tion gives better results than do corresponding W- and V- activated peroxide delignifications (compare Experiments 1, 2 and 3) .
  • W- and V-activated peroxide/peracid delignifications give better results than do corresponding peroxide delignifi ⁇ cations.
  • An addition of silicate promotes w- and V-activated peroxide and peracid delignifications.
  • a softwood sulfate pulp was chelate-treated with different complex formers. Before the treatment, the stock had the fol ⁇ lowing heavy-metal concentrations: Fe 3.8 mg/kg of pulp (ppm), Mn 24 ppm. The copper concentration in the stock was insig ⁇ nificant.
  • Softwood sulfate pulp before chelation Kappa 9, viscosity 720 dm 3 /kg, Fe 3.8 mg/kg pulp (ppm), Mn 24 ppm.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)

Abstract

L'invention concerne un procédé de délignification d'une pâte chimique, par exemple d'une pâte au sulfate ou au sulfite, où la pâte est traitée avec un peroxyde et/ou un peracide en présence d'un activateur renfermant un métal de transition du groupe du titane, du groupe du vanadium ou du groupe du chrome, comme par exemple le molybdène, le vanadium ou le tungstène. L'invention repose essentiellement sur le fait qu'avant ce traitement au peroxyde et/ou au peracide, on élimine de la pâte les métaux lourds amenés par le bois tels que le fer, le manganèse et/ou le cuivre, en utilisant un agent chélatant. L'agent chélatant convertit les métaux lourds en sels complexes solubles qui sont éliminés avec la solution de l'agent chélatant ou avec les eaux de lavage. Le traitement par l'agent chélatant et le traitement par le peroxyde et/ou le peracide font partie d'une opération de blanchiment qui peut comprendre d'autres étapes de traitement, par exemple un traitement par l'oxygène, une seconde étape de traitement par un agent chélatant ou un traitement par un peroxyde alcalin.
PCT/FI1995/000353 1994-06-20 1995-06-19 Delignification d'une pate chimique avec un peroxyde en presence d'un metal de transition WO1995035408A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU27400/95A AU2740095A (en) 1994-06-20 1995-06-19 Delignification of chemical pulp with peroxide in the presence of transition metal

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI942968A FI942968A (fi) 1994-06-20 1994-06-20 Menetelmä kemiallisen massan delignifioimiseksi
FI942968 1994-06-20

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Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996037654A1 (fr) * 1995-05-22 1996-11-28 Mo Och Domsjö Aktiebolag Blanchiment de pate de cellulose en une seule et meme etape avec un agent complexant, une substance contenant du molybdene et un agent de blanchiment oxydant
FR2813896A1 (fr) * 2000-09-14 2002-03-15 Atofina Procede de delignification et blanchiment par un oxydant et un catalyseur d'oxydoreduction
WO2003049880A1 (fr) * 2001-12-06 2003-06-19 Kazem Eradat Oskoui Procede d'extraction de substances contaminantes presentes dans des matieres solides
WO2006119392A1 (fr) * 2005-05-02 2006-11-09 International Paper Company Materiaux lignocellulosiques et produits fabriques a partir de ces materiaux
US8262850B2 (en) 2003-09-23 2012-09-11 International Paper Company Chemical activation and refining of southern pine kraft fibers
RU2523118C1 (ru) * 2013-06-17 2014-07-20 федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Пермский национальный исследовательский политехнический университет" Способ отбелки лиственной сульфатной целлюлозы
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
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
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
US9512237B2 (en) 2009-05-28 2016-12-06 Gp Cellulose Gmbh Method for inhibiting the growth of microbes with a modified cellulose fiber
US9951470B2 (en) 2013-03-15 2018-04-24 Gp Cellulose Gmbh Low viscosity kraft fiber having an enhanced carboxyl content 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
US10865519B2 (en) 2016-11-16 2020-12-15 Gp Cellulose Gmbh Modified cellulose from chemical fiber and methods of making and using the same
US11332886B2 (en) 2017-03-21 2022-05-17 International Paper Company Odor control pulp composition

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4410397A (en) * 1978-04-07 1983-10-18 International Paper Company Delignification and bleaching process and solution for lignocellulosic pulp with peroxide in the presence of metal additives
US4427490A (en) * 1978-04-07 1984-01-24 International Paper Company Delignification and bleaching process for lignocellulosic pulp with peroxide in the presence of metal additives
US4661205A (en) * 1981-08-28 1987-04-28 Scott Paper Company Method of bleaching lignocellulosic material with peroxide catalyzed with a salt of a metal
EP0578303A1 (fr) * 1992-07-06 1994-01-12 Solvay Interox Procédé pour la délignification d'une pâte à papier chimique

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4410397A (en) * 1978-04-07 1983-10-18 International Paper Company Delignification and bleaching process and solution for lignocellulosic pulp with peroxide in the presence of metal additives
US4427490A (en) * 1978-04-07 1984-01-24 International Paper Company Delignification and bleaching process for lignocellulosic pulp with peroxide in the presence of metal additives
US4661205A (en) * 1981-08-28 1987-04-28 Scott Paper Company Method of bleaching lignocellulosic material with peroxide catalyzed with a salt of a metal
EP0578303A1 (fr) * 1992-07-06 1994-01-12 Solvay Interox Procédé pour la délignification d'une pâte à papier chimique

Cited By (35)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996037654A1 (fr) * 1995-05-22 1996-11-28 Mo Och Domsjö Aktiebolag Blanchiment de pate de cellulose en une seule et meme etape avec un agent complexant, une substance contenant du molybdene et un agent de blanchiment oxydant
FR2813896A1 (fr) * 2000-09-14 2002-03-15 Atofina Procede de delignification et blanchiment par un oxydant et un catalyseur d'oxydoreduction
WO2002022944A1 (fr) * 2000-09-14 2002-03-21 Atofina Procede de delignification et blanchiment par un oxydant et un catalyseur d'oxydoreduction
WO2003049880A1 (fr) * 2001-12-06 2003-06-19 Kazem Eradat Oskoui Procede d'extraction de substances contaminantes presentes dans des matieres solides
US8262850B2 (en) 2003-09-23 2012-09-11 International Paper Company Chemical activation and refining of southern pine kraft fibers
JP2018087403A (ja) * 2005-05-02 2018-06-07 インターナショナル・ペーパー・カンパニー リグノセルロース系材料及びこれから製造した生成物
WO2006119392A1 (fr) * 2005-05-02 2006-11-09 International Paper Company Materiaux lignocellulosiques et produits fabriques a partir de ces materiaux
US8007635B2 (en) 2005-05-02 2011-08-30 International Paper Company Lignocellulosic materials and the products made therefrom
EP2527531A1 (fr) * 2005-05-02 2012-11-28 International Paper Company Matériaux lignocellulosiques et produits obtenus à partir de ceux-ci
EP3575489A1 (fr) * 2005-05-02 2019-12-04 International Paper Company Matériaux lignocellulosiques et produits obtenus à partir de ceux-ci
EP2840182A1 (fr) * 2005-05-02 2015-02-25 International Paper Company Matériaux lignocellulosiques et produits obtenus à partir de ceux-ci
US10907304B2 (en) 2005-05-02 2021-02-02 International Paper Company Ligno cellulosic materials and the products made therefrom
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
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
US9512237B2 (en) 2009-05-28 2016-12-06 Gp Cellulose Gmbh Method for inhibiting the growth of microbes with a modified cellulose fiber
US9777432B2 (en) 2009-05-28 2017-10-03 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US9909257B2 (en) 2009-05-28 2018-03-06 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US9926666B2 (en) 2009-05-28 2018-03-27 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
US11111628B2 (en) 2009-05-28 2021-09-07 Gp Cellulose Gmbh Modified cellulose from chemical kraft fiber and methods of making and using the same
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
US10731293B2 (en) 2009-05-28 2020-08-04 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
USRE49570E1 (en) 2009-05-28 2023-07-04 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
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
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
US10550516B2 (en) 2013-03-15 2020-02-04 Gp Cellulose Gmbh Low viscosity kraft fiber having an enhanced carboxyl content and methods of making and using the same
US10753043B2 (en) 2013-03-15 2020-08-25 Gp Cellulose Gmbh Low viscosity kraft fiber having an enhanced carboxyl content and methods of making and using the same
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
US9951470B2 (en) 2013-03-15 2018-04-24 Gp Cellulose Gmbh Low viscosity kraft fiber having an enhanced carboxyl content and methods of making and using the same
RU2523118C1 (ru) * 2013-06-17 2014-07-20 федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Пермский национальный исследовательский политехнический университет" Способ отбелки лиственной сульфатной целлюлозы
US10865519B2 (en) 2016-11-16 2020-12-15 Gp Cellulose Gmbh Modified cellulose from chemical fiber and methods of making and using the same
US11332886B2 (en) 2017-03-21 2022-05-17 International Paper Company Odor control pulp composition
US11613849B2 (en) 2017-03-21 2023-03-28 International Paper Company Odor control pulp composition

Also Published As

Publication number Publication date
FI942968A0 (fi) 1994-06-20
FI942968A (fi) 1995-12-21
AU2740095A (en) 1996-01-15

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