EP0881326A1 - Process for producing bleached special cellulose pulps - Google Patents

Process for producing bleached special cellulose pulps Download PDF

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Publication number
EP0881326A1
EP0881326A1 EP97108710A EP97108710A EP0881326A1 EP 0881326 A1 EP0881326 A1 EP 0881326A1 EP 97108710 A EP97108710 A EP 97108710A EP 97108710 A EP97108710 A EP 97108710A EP 0881326 A1 EP0881326 A1 EP 0881326A1
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EP
European Patent Office
Prior art keywords
bleaching
pulp
pulps
derivatives
fibers
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.)
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EP97108710A
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German (de)
French (fr)
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EP0881326B1 (en
Inventor
Jiri Voronecky
Jörg Kühn
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Glatfelter Gernsbach GmbH and Co KG
Original Assignee
Papierfabrik Schoeller & Hoesch GmbH
Papierfabrik Schoeller and Hoesch GmbH and Co KG
Schoeller und Hoesch GmbH
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Application filed by Papierfabrik Schoeller & Hoesch GmbH, Papierfabrik Schoeller and Hoesch GmbH and Co KG, Schoeller und Hoesch GmbH filed Critical Papierfabrik Schoeller & Hoesch GmbH
Priority to DK97108710T priority Critical patent/DK0881326T3/en
Priority to DE59704964T priority patent/DE59704964D1/en
Priority to AT97108710T priority patent/ATE207153T1/en
Priority to EP97108710A priority patent/EP0881326B1/en
Priority to ES97108710T priority patent/ES2164279T3/en
Priority to PT97108710T priority patent/PT881326E/en
Publication of EP0881326A1 publication Critical patent/EP0881326A1/en
Application granted granted Critical
Publication of EP0881326B1 publication Critical patent/EP0881326B1/en
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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
    • D21C5/00—Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting materials
    • 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

Definitions

  • the present invention relates to a method for manufacturing of bleached special pulps from annual plants the preamble of claim 1.
  • the physical properties of paper include, for example Basis weight, paper thickness, volume, porosity, mechanical strength, whiteness, opacity, etc.
  • Chemical properties are, for example, the alkalinity of the Paper, amount and type of fillers, amount and type of impregnation salts, Amount and type of polysaccharide components in the raw material used, e.g. of pentosans, lot and type of non-polysaccharide residues used in the Raw material such as resin, etc., amount and kind of in the manufacturing process auxiliary materials used etc.
  • the processes involved in the manufacture of pulp be applied to ensure that the optimal paper-technical properties of the pulp during production also achieved and the important cellulose components of the Raw fiber material can be obtained to the maximum amount To obtain pulp with the desired properties.
  • the determination of the viscosity or the degree of polymerization belongs in the optimization of paper technology Properties of pulp to the important criteria for the Choice of pulp.
  • paper types that are supposed to be lightweight (e.g. 7.0 - 35 g / m 2 ) and have good filtration properties for gases and liquids (e.g. highly porous filter wrapping papers for cigarette filters, cigarette paper, teabag filter papers etc.) or have good impregnation properties (e.g. electrolytic Papers, fiber intestinal papers, etc.), special pulps based on annual plants are required as fiber raw materials.
  • gases and liquids e.g. highly porous filter wrapping papers for cigarette filters, cigarette paper, teabag filter papers etc.
  • impregnation properties e.g. electrolytic Papers, fiber intestinal papers, etc.
  • special pulps based on annual plants are required as fiber raw materials.
  • the plants are processed into special pulp generally in a first stage by means of a mechanical and / or biological process.
  • the unwanted vegetable parts removed.
  • the non-cellulose-containing components are broken down and the chemical digestion for the subsequent chemical Process facilitated.
  • the fibrous raw material becomes certain components, i.e. the unwanted vegetable Parts removed, which are the removed components act about 20 to even 70 wt .-% of the original mass can.
  • the bleaching process depends on the bleach and used method of the degree of polymerization of the pulp reduced. Such a reduction during the bleaching process is predominantly undesirable, however, because the degree of polymerization is reduced e.g. the solubility of the pulp, its behavior in the initial or slightly ground state and the ability to impregnate of the individual fibers changes.
  • the object of the present invention is therefore a method specify for the production of bleached special pulps, with a clear one with the same whiteness of the pulp Reduction in the degradation of the degree of polymerization of the pulp is achieved in the bleaching process.
  • Special pulp can according to the invention according to the desired Properties from a wide variety of fiber materials getting produced.
  • suitable fiber-donating plants such as flax (Linum usitatissimum), Hemp (Canabis Sativa), jute (Carchorus olitorius), Kenaf (Hibiscus Sabdoriffa), Sun hemp (Crotalaria junicea), Manila hemp (Musa textilis), Sisal (Agave sisalina), Esparto (Stipa tenacissima) etc.
  • flax Lium usitatissimum
  • Hemp Canabis Sativa
  • jute Carchorus olitorius
  • Kenaf Hibiscus Sabdoriffa
  • Sun hemp Crotalaria junicea
  • Manila hemp Mosal (Agave sisalina), Esparto (Stipa tenacissima) etc.
  • the fiber donors Plants under a mechanical or biological Process or a combination thereof from the undesirable exempted from vegetable parts.
  • a fiberization then takes place in a further process step of the plants in single fibers in a chemical-mechanical Process stage.
  • they are already mechanical or biologically prepared fibers with inorganic and / or organic chemicals cooked and, if necessary, mechanically frayed.
  • usable organic chemicals to influence the delignification process for example Call antrachinone.
  • Any pulp obtained from the cooking process Cooking process for example an alkaline process or a neutral sulfite process.
  • it can be according to the invention in the case of the pulps used for pulps Trade hard fibers or pulps from soft fibers.
  • the pulp obtained during the cooking process is then as part of a single or multi-stage bleaching process bleached.
  • this bleaching takes place under Use of additives. It is expedient in the additives around aromatic hydrocarbons.
  • aromatic used according to the invention Hydrocarbons are naphthalene or derivatives thereof or Antrachinone or derivatives thereof, in particular antrachinone or Derivatives thereof, such as 9,10-antrachinone.
  • the additives are usually used in amounts of 0.001 to 10% by weight, expediently from 0.01 to 1% by weight, preferably from 0.05 to 0.55% by weight, in particular 0.1 to 0.3% by weight, based on the mass of absolutely dry fibers, which is to be dispersed in the bleaching liquor.
  • bleaching is used in the bleaching process of chlorine and its derivatives and the chlorine-free bleaching processes using other special oxidizing agents distinguished.
  • One of the oldest bleaching agents is chlorine and its derivatives. Because when bleaching with chlorine or its derivatives organically bound chlorine derivatives, which are undesirable for environmental reasons are larger (when using chlorine gas) or smaller amounts (when using chlorine dioxide) arise this type of bleaching process is less preferred today.
  • a bleaching process using chlorine-free bleaching agents for example using oxygen (O 2 ), ozone (O 3 ), hydrogen peroxide (H 2 O 2 ), peracetic acid (C 2 H 4 ), is predominantly used today O 3 ) etc., preferred.
  • the bleaching process can be a single or multi-stage bleaching process using chlorine or derivatives thereof or a single or multi-stage chlorine-free Act bleaching process. It is preferably chlorine-free Bleaching process from several bleaching stages.
  • the bleaching liquor contains various others Components such as bleaching chemicals and other auxiliary components.
  • the bleaching liquor for example, can contain chelating agents such as sodium diethylenetriaminepentaacetate (DTPA). , are added. These chelating agents bind the metals contained in the bleaching liquor and thus prevent catalytic decomposition of the bleaching agents.
  • chelating agents such as sodium diethylenetriaminepentaacetate (DTPA).
  • the intrinsic viscosity is defined as follows:
  • Example 1 unbleached cellulose made from kenaf or abaca fibers was used as the pulp.
  • the pulp suspension was adjusted to the desired consistency, adjusted to the desired pH with NaOH, buffered with sodium silicate, heated and mixed with H 2 O 2 as a bleaching chemical.
  • Naphthalene or antrachinone was used as an additive in an amount of 0.2% additive per kg of absolutely dry fibers.
  • compositions of the bleaching liquors used are given below: Trial 1 Additive [type] 0 naphthalene Pulp [type] Kenaf Kenaf Amount of fibers [kg] 7.00 7.00 H 2 O [kg] 92,072 92,072 NaOH 100% [kg] 0.088 0.088 pH 10.8 10.8 Sodium silicate [kg] 0.140 0.140 Temperature [° C] 70 70 Bleaching time [h] 3.0 3.0 H 2 O 2 35% [kg] 0.700 0.700 Trial 2 Additive [type] 0 naphthalene Pulp [type] Abaca Abaca Amount of fibers [kg] 7.00 7.00 H 2 O [kg] 92,072 92,072 NaOH 100% [kg] 0.088 0.088 pH 10.9 10.9 Sodium silicate [kg] 0.140 0.140 Temperature [° C] 70 70 Bleaching time [h] 3.0 3.0 H 2 O 2 35% [kg] 0.700 0.700 Trial 3 Additive [type] 0 Antrachin

Abstract

Reduction of degradation of cellulose and its derivatives in the production of bleached special pulp from annual plants comprises using additives (I) that do not react with the half stuff, bleaching chemicals and other components of the bleaching liquor but inhibit degradation.

Description

Die vorliegende Erfindung betrifft ein Verfahren zur Herstellung von gebleichten Spezialzellstoffen aus Einjahrespflanzen nach dem Oberbegriff des Patentanspruchs 1.The present invention relates to a method for manufacturing of bleached special pulps from annual plants the preamble of claim 1.

Bekanntlich werden entsprechend den angestrebten Eigenschaften unterschiedliche Holzarten, die die gewünschten Eigenschaften zu liefern vermögen, für Zellstoffe eingesetzt. Bei den unterschiedlichen Eigenschaften wird die Wahl insbesondere im Hinblick auf die gewünschten chemischen und physikalischen Eigenschaften des Papiers, das aus dem Zellstoff hergestellt werden soll, ausgerichtet.As is known, according to the desired properties different types of wood that add the desired properties deliver assets used for pulp. With the different The choice is particularly with regard to properties on the desired chemical and physical properties of the paper that is made from the pulp should be aligned.

Zu den physikalischen Eigenschaften des Papiers gehören beispielsweise Flächengewicht, Papierdicke, Volumen, Porosität, mechanische Festigkeit, Weißgrad, Opazität usw.The physical properties of paper include, for example Basis weight, paper thickness, volume, porosity, mechanical strength, whiteness, opacity, etc.

Chemische Eigenschaften sind beispielsweise die Alkalität des Papiers, Menge und Art der Füllstoffe, Menge und Art der Imprägnierungssalze, Menge und Art der polysaccharidischen Komponenten im verwendeten Rohmaterial, wie z.B. von Pentosanen, Menge und Art der nicht-polysaccharidischen Reststoffe im verwendeten Rohmaterial, wie z.B Harz usw., Menge und Art der beim Herstellungsprozeß verwendeten Hilfsstoffe usw.Chemical properties are, for example, the alkalinity of the Paper, amount and type of fillers, amount and type of impregnation salts, Amount and type of polysaccharide components in the raw material used, e.g. of pentosans, lot and type of non-polysaccharide residues used in the Raw material such as resin, etc., amount and kind of in the manufacturing process auxiliary materials used etc.

Daneben ist bei den Prozessen, die bei der Herstellung von Zellstoff angewendet werden, darauf zu achten, daß die optimalen papiertechnischen Eigenschaften des Zellstoffs bei der Herstellung auch erreicht und die wichtigen Cellulosekomponenten des Rohfasermaterials erhalten werden, um die maximale Menge an Zellstoff mit den gewünschten Eigenschaften zu gewinnen.In addition, the processes involved in the manufacture of pulp be applied to ensure that the optimal paper-technical properties of the pulp during production also achieved and the important cellulose components of the Raw fiber material can be obtained to the maximum amount To obtain pulp with the desired properties.

Im Hinblick auf die Kontrolle der bei der Zellstoffherstellung notwendigen chemischen Prozesse dienen meist die Messung des Restligningehalts (z.B. die Kappa-Zahl nach DIN 54 357) sowie die Bestimmung des Abbaugrads der polysaccharidischen Komponenten (z.B. die Viskosität nach SCAN C15:62) als geeignete Parameter zur Koordination der Verfahrensparameter.With regard to the control of the pulp production necessary chemical processes mostly serve the measurement of Residual lignin content (e.g. the kappa number according to DIN 54 357) and the determination of the degree of degradation of the polysaccharidic components (e.g. the viscosity according to SCAN C15: 62) as suitable parameters to coordinate the process parameters.

Insbesondere die Bestimmung der Viskosität bzw. des Polymerisationsgrads gehört bei der Optimierung der papiertechnischen Eigenschaften von Zellstoffen zu den wichtigen Kriterien für die Auswahl des Zellstoffs.In particular the determination of the viscosity or the degree of polymerization belongs in the optimization of paper technology Properties of pulp to the important criteria for the Choice of pulp.

So sind beispielsweise für bestimmte Papiersorten papiertechnische Eigenschaften des Zellstoffs gewünscht, die nur durch spezielle Rohfasermaterialien und einen geeigneten Herstellungsprozeß erreichbar sind.For example, there are paper technologies for certain types of paper Properties of the pulp desired only by special Raw fiber materials and a suitable manufacturing process are reachable.

Beispielsweise werden für Papiersorten, die leichtgewichtig sein sollen (z.B. 7,0 - 35 g/m2) und dabei gute Filtrationseigenschaften für Gase und Flüssigkeiten besitzen (z.B. hochporöse Filterumhüllungspapiere für Zigarettenfilter, Zigarettenpapier, Teebeutelfilterpapiere usw.) oder gute Imprägnierungsfähigkeit besitzen (z.B. elektrolytische Papiere, Faserdarmpapiere usw.), Spezialzellstoffe auf der Basis von Einjahrespflanzen als Faserrohstoff benötigt.For example, for paper types that are supposed to be lightweight (e.g. 7.0 - 35 g / m 2 ) and have good filtration properties for gases and liquids (e.g. highly porous filter wrapping papers for cigarette filters, cigarette paper, teabag filter papers etc.) or have good impregnation properties (e.g. electrolytic Papers, fiber intestinal papers, etc.), special pulps based on annual plants are required as fiber raw materials.

Die Verarbeitung der Pflanzen zu Spezialzellstoff erfolgt dabei allgemein in einer ersten Stufe mittels eines mechanischen und/oder biologischen Prozesses. Hierbei werden die unerwünschten pflanzlichen Teile entfernt. Im biologischen Prozeß werden insbesondere die nicht-cellulosehaltige Komponenten abgebaut und der chemische Aufschluß für den sich anschließenden chemischen Prozeß erleichtert.The plants are processed into special pulp generally in a first stage by means of a mechanical and / or biological process. Here, the unwanted vegetable parts removed. In the biological process especially the non-cellulose-containing components are broken down and the chemical digestion for the subsequent chemical Process facilitated.

Die anschließende Zerfaserung der Pflanzen in Einzelfasern wird üblicherweise in einem kombinierten chemischen-mechanischen Prozeß vorgenommen.The subsequent shredding of the plants into individual fibers usually in a combined chemical-mechanical Process made.

Bei dem genannten Zerfasern werden aus dem faserigen Rohmaterial bestimmte Komponenten, d.h. die unerwünschten pflanzlichen Teile, entfernt, wobei es sich bei den entfernten Komponenten um etwa 20 bis sogar 70 Gew.-% der ursprünglichen Masse handeln kann.In the case of said defibering, the fibrous raw material becomes certain components, i.e. the unwanted vegetable Parts removed, which are the removed components act about 20 to even 70 wt .-% of the original mass can.

Bei dem sich anschließenden ein- oder mehrstufigen Bleichen wird ungebleichter Zellstoff als Halbstoff nach dem Abschluß des Kochprozesses (ca. 50 - 75% der Rohfasern) und der eventuell durchgeführten mechanischen Zerfaserung einer Behandlung mit Chemikalien mit oxidativem Charakter unterzogen. Ziel des Bleichprozesses ist es hierbei, die Reste von Lignin, farbwirkenden Substanzen, Holocellulose und "Schäben" zumindestens teilweise zu entfernen.In the subsequent single or multi-stage bleaching unbleached pulp as pulp after the completion of the Cooking process (approx. 50 - 75% of the raw fibers) and possibly performed mechanical defibration with a treatment Chemicals with an oxidative character. target of The bleaching process here is the remains of lignin, color-acting Substances, holocellulose and "shives" at least partially remove.

Beim Bleichprozeß wird jedoch abhängig vom Bleichmittel und eingesetztem Verfahren der Polymerisationsgrad des Zellstoffs reduziert. Eine derartige Reduktion während des Bleichprozesses ist jedoch überwiegend unerwünscht, da ein Abbau des Polymerisationsgrades z.B. die Löslichkeit des Zellstoffes, dessen Verhalten in initialem bzw. leicht gemahlenem Zustand und die Imprägnationsfähigkeit der Einzelfasern ändert.The bleaching process depends on the bleach and used method of the degree of polymerization of the pulp reduced. Such a reduction during the bleaching process is predominantly undesirable, however, because the degree of polymerization is reduced e.g. the solubility of the pulp, its behavior in the initial or slightly ground state and the ability to impregnate of the individual fibers changes.

Aufgabe der vorliegenden Erfindung ist es somit, ein Verfahren zur Herstellung von gebleichten Spezialzellstoffen anzugeben, bei dem bei gleichbleibendem Weißegrad des Zellstoffs eine deutliche Verringerung des Abbaus des Polymerisationsgrads des Halbstoffs beim Bleichprozeß erreicht wird.The object of the present invention is therefore a method specify for the production of bleached special pulps, with a clear one with the same whiteness of the pulp Reduction in the degradation of the degree of polymerization of the pulp is achieved in the bleaching process.

Die Lösung dieser Aufgabe ergibt sich erfindungsgemäß aus den in Patentanspruch 1 angegebenen Merkmalen.This object is achieved according to the invention from the in Claim 1 specified features.

Vorteilhafte Weiterbildungen der Erfindung finden sich in den Patentansprüchen 2 bis 9.Advantageous developments of the invention can be found in the Claims 2 to 9.

Erfindungsgemäß wurde festgestellt, daß bei Mitverwendung von speziellen Additiven im Rahmen des Bleichprozesses der Abbau des Polymerisationsgrads des Zellstoffs während des Bleichens deutlich geringer ist. According to the invention it was found that when using special additives as part of the bleaching process the degradation of the Degree of polymerization of the pulp clearly during bleaching is less.

Spezialzellstoff kann erfindungsgemäß entsprechend den angestrebten Eigenschaften aus den verschiedensten Faserstoffen hergestellt werden.Special pulp can according to the invention according to the desired Properties from a wide variety of fiber materials getting produced.

Erfindungsgemäß können zur Herstellung der Spezialzellstoffe geeignete faserspendende Pflanzen wie Flachs (Linum usitatissimum), Hanf (Canabis Sativa), Jute (Carchorus olitorius), Kenaf (Hibiscus Sabdoriffa), Sunnhanf (Crotalaria junicea), Manilahanf (Musa textilis), Sisal (Agave sisalina), Esparto (Stipa tenacissima) usw. verwendet werden.According to the invention for the production of special pulps suitable fiber-donating plants such as flax (Linum usitatissimum), Hemp (Canabis Sativa), jute (Carchorus olitorius), Kenaf (Hibiscus Sabdoriffa), Sun hemp (Crotalaria junicea), Manila hemp (Musa textilis), Sisal (Agave sisalina), Esparto (Stipa tenacissima) etc. can be used.

In einer ersten Stufe der Zellstoffherstellung werden die faserspendenden Pflanzen im Rahmen eines mechanischen oder biologischen Verfahrens oder einer Kombination hiervon von den unerwünschten pflanzlichen Teilen befreit.In a first stage of pulp production, the fiber donors Plants under a mechanical or biological Process or a combination thereof from the undesirable exempted from vegetable parts.

In einem weiteren Verfahrensschritt erfolgt dann eine Zerfaserung der Pflanzen in Einzelfasern in einer chemisch-mechanischen Verfahrensstufe. Zu diesem Zweck werden die bereits mechanisch bzw. biologisch vorbereiteten Fasern mit anorganischen und/oder organischen Chemikalien gekocht und gegebenenfalls mechanisch zerfasert. Als Beispiel für verwendbare organische Chemikalien zur Beeinflussung des Delignifizierungsprozesses läßt sich beispielsweise Antrachinon nennen. Erfindungsgemäß kann der im Rahmen des Kochprozesses gewonnene Halbstoff aus einem beliebigen Kochprozeß, beispielsweise einem alkalischen Verfahren oder einem Neutralsulfit-Verfahren stammen. Ferner kann es sich erfindungsgemäß bei den verwendeten Halbstoffen um Halbstoffe aus Hartfasern oder Halbstoffe aus Weichfasern handeln.A fiberization then takes place in a further process step of the plants in single fibers in a chemical-mechanical Process stage. For this purpose, they are already mechanical or biologically prepared fibers with inorganic and / or organic chemicals cooked and, if necessary, mechanically frayed. As an example of usable organic chemicals to influence the delignification process, for example Call antrachinone. According to the invention Any pulp obtained from the cooking process Cooking process, for example an alkaline process or a neutral sulfite process. Furthermore, it can be according to the invention in the case of the pulps used for pulps Trade hard fibers or pulps from soft fibers.

Der im Rahmen des Kochprozesses gewonnene Halbstoff wird anschließend im Rahmen eines ein- oder mehrstufigen Bleichprozesses gebleicht. Dieses Bleichen erfolgt erfindungsgemäß unter Mitverwendung von Additiven. Zweckmäßigerweise handelt es sich bei den Additiven um aromatische Kohlenwasserstoffe. Bevorzugte Beispiele für erfindungsgemäß verwendbare aromatische Kohlenwasserstoffe sind Naphthalin oder Derivate hiervon oder Antrachinon oder Derivate hiervon, insbesondere Antrachinon oder Derivate hiervon, wie z.B. 9,10-Antrachinon.The pulp obtained during the cooking process is then as part of a single or multi-stage bleaching process bleached. According to the invention, this bleaching takes place under Use of additives. It is expedient in the additives around aromatic hydrocarbons. Preferred Examples of aromatic used according to the invention Hydrocarbons are naphthalene or derivatives thereof or Antrachinone or derivatives thereof, in particular antrachinone or Derivatives thereof, such as 9,10-antrachinone.

Die Additive werden erfindungsgemäß gewöhnlich in Mengen von 0,001 bis 10 Gew.-%, zweckmäßigerweise von 0,01 bis 1 Gew.-%, vorzugsweise von 0,05 bis 0,55 Gew.-%, insbesondere 0,1 bis 0,3 Gew.-%, bezogen auf die Masse an absolut trockenen Fasern, die in der Bleichflotte dispergiert werden soll, zugesetzt.According to the invention, the additives are usually used in amounts of 0.001 to 10% by weight, expediently from 0.01 to 1% by weight, preferably from 0.05 to 0.55% by weight, in particular 0.1 to 0.3% by weight, based on the mass of absolutely dry fibers, which is to be dispersed in the bleaching liquor.

Allgemein wird beim Bleichprozeß das Bleichen unter Verwendung von Chlor und dessen Derivaten und die chlorfreien Bleichprozesse unter Verwendung anderer besonderer Oxidationsmittel unterschieden.Generally, bleaching is used in the bleaching process of chlorine and its derivatives and the chlorine-free bleaching processes using other special oxidizing agents distinguished.

Eines der ältesten Bleichmittel ist Chlor und dessen Derivate. Da bei einem Bleichen mit Chlor oder dessen Derivaten hiervon organisch gebundene Chlorderivate, die aus Umweltgründen unerwünscht sind, in größeren (bei Verwendung von Chlorgas) oder kleineren (bei Verwendung von Chlordioxid) Mengen entstehen, ist diese Art von Bleichprozeß heute weniger bevorzugt.One of the oldest bleaching agents is chlorine and its derivatives. Because when bleaching with chlorine or its derivatives organically bound chlorine derivatives, which are undesirable for environmental reasons are larger (when using chlorine gas) or smaller amounts (when using chlorine dioxide) arise this type of bleaching process is less preferred today.

Im Hinblick auf die Umwelteinflüsse von organisch gebundenen Chlorderivaten wird folglich heute überwiegend ein Bleichprozeß unter Verwendung chlorfreier Bleichmittel, beispielsweise unter Verwendung von Sauerstoff (O2), Ozon (O3), Wasserstoffperoxid (H2O2), Peressigsäure (C2H4O3) usw., bevorzugt.With regard to the environmental influences of organically bound chlorine derivatives, a bleaching process using chlorine-free bleaching agents, for example using oxygen (O 2 ), ozone (O 3 ), hydrogen peroxide (H 2 O 2 ), peracetic acid (C 2 H 4 ), is predominantly used today O 3 ) etc., preferred.

Erfindungsgemäß kann es sich bei dem Bleichverfahren um ein ein- oder mehrstufiges Bleichverfahren unter Verwendung von Chlor oder Derivaten hiervon oder um ein ein- oder mehrstufiges chlorfreies Bleichverfahren handeln. Vorzugsweise besteht das chlorfreie Bleichverfahren aus mehreren Bleichstufen.According to the invention, the bleaching process can be a single or multi-stage bleaching process using chlorine or derivatives thereof or a single or multi-stage chlorine-free Act bleaching process. It is preferably chlorine-free Bleaching process from several bleaching stages.

Erfindungsgemäß ist es bei der Herstellung von Spezialzellstoffen aus Einjahrespflanzen aus technischen und Kostengründen bevorzugt, das Bleichverfahren in einem Aggregat (beispielsweise Bleichbütte, Bleichholländer, usw.) durchzuführen. Auf diese Weise ist es möglich, auf eine Zwischenwäsche zu verzichten. It is according to the invention in the production of special pulps from annual plants for technical and cost reasons preferably, the bleaching process in an aggregate (for example Bleaching chest, bleaching dutch, etc.). To this In this way it is possible to do without an intermediate wash.

Die Bleichflotte enthält neben dem Halbstoff verschiedene andere Bestandteile, wie Bleichchemikalien und andere Hilfskomponenten.In addition to the pulp, the bleaching liquor contains various others Components such as bleaching chemicals and other auxiliary components.

Um insbesondere bei chlorfreien Bleichen den Einfluß von Metallen, wie Mn++, Fe++ und Cu++, in Form einer katalytischen Zersetzung der Bleichmittel, beispielsweise von Peroxiden zu vermeiden, können der Bleichflotte beispielsweise Chelatbildner, wie Natrium-diethylentriaminpentaacetat (DTPA), zugesetzt werden. Diese Chelatbildner binden die in der Bleichflotte enthaltenen Metalle und verhindern somit eine katalytische Zersetzung der Bleichmittel.In order to avoid the influence of metals, such as Mn ++ , Fe ++ and Cu ++ , in the form of catalytic decomposition of the bleaching agents, for example peroxides, in particular in the case of chlorine-free bleaching, the bleaching liquor, for example, can contain chelating agents such as sodium diethylenetriaminepentaacetate (DTPA). , are added. These chelating agents bind the metals contained in the bleaching liquor and thus prevent catalytic decomposition of the bleaching agents.

Zur Bestimmung des Polymerisationsgrads des nach dem Bleichen erhaltenen Zellstoffs stehen mehrere Methoden zur Verfügung. Die Verfahren erfordern jedoch überwiegend eine erheblichen apparativen und Zeitaufwand, so daß sie zur Routineprüfung von Zellstoffen nicht in Frage kommen.To determine the degree of polymerization after bleaching The pulp obtained has several methods available. The However, processes predominantly require considerable equipment and time spent making routine pulp testing not acceptable.

Die einfachste Methode, die eine Bestimmung des Polymerisationsgrads ermöglicht, ist die Messung der Viskosität von Zellstofflösungen mit Hilfe von Kapillarviskosimetern. Eine Ableitung des Polymerisationsgrads aus Viskositätsmessungen stellte schon 1930 Staudinger fest. [η]=KMM The simplest method that enables the degree of polymerization to be determined is to measure the viscosity of pulp solutions using capillary viscometers. Staudinger found a derivation of the degree of polymerization from viscosity measurements as early as 1930. [η] = K M M

Hier bedeuten:

[η]
Grenzviskosität
KM
Konstante
M
Molmasse
Here mean:
[η]
Intrinsic viscosity
K M
constant
M
molar mass

Die Grenzviskosität wird wie folgt definiert:

Figure 00060001
The intrinsic viscosity is defined as follows:
Figure 00060001

Hier bedeuten:

η
Viskosität einer Zellstofflösung
ηo
Viskosität des verwendeten Lösungsmittels
t
Auslaufzeit einer Zellstofflösung im Viskosimeter
to
Auslaufzeit eines Lösungsmittels im Viskosimeter
c
Konzentration der Zellstofflösung
Here mean:
η
Viscosity of a pulp solution
η o
Viscosity of the solvent used
t
Expiration time of a cellulose solution in the viscometer
t o
Flow time of a solvent in the viscometer
c
Concentration of the pulp solution

Später wurde die Staudinger-Lösung des Zusammenhangs zwischen Viskosität und Molmasse weiter präzisiert (z.B durch die Staudinger-Mark-Houwink-Gleichung), wobei jedoch der direkte Zusammenhang der Viskosität mit der Molmasse bestehen blieb. Diese Gesetzmäßigkeit hat folglich in der Praxis durch unterschiedliche Normen (z.B. TAPPI, T206, ISO 5351/1, SCAN C15:62 usw.) breite Anwendung gefunden.Later the Staudinger solution of the connection between Viscosity and molar mass further specified (e.g. using the Staudinger-Mark-Houwink equation), but the direct connection the viscosity with the molar mass remained. This In practice, lawfulness therefore has different Standards (e.g. TAPPI, T206, ISO 5351/1, SCAN C15: 62 etc.) widely used.

Im folgenden wird die vorliegende Erfindung anhand einiger Beispiele, die die vorliegende Erfindung in keiner Weise einschränken sollen, weiter veranschaulicht.In the following, the present invention is illustrated by means of a few examples, which in no way limit the present invention are further illustrated.

Beispiel 1example 1

Als Halbstoff wurde in Beispiel 1 ungebleichter Zellstoff aus Kenaf- bzw. Abaca-Fasern verwendet. Die Halbstoffsuspension wurde auf die gewünschte Konsistenz eingestellt, mit NaOH auf den gewünschten pH-Wert eingestellt, mit Natriumsilikat gepuffert, erwärmt und mit H2O2 als Bleichchemikalie versetzt. Als Additiv wurde Naphthalin bzw. Antrachinon verwendet in einer Menge von 0,2% Additiv pro kg absolut trockene Fasern. Die Zusammensetzungen der verwendeten Bleichflotten sind im folgenden angegeben: Versuch 1 Additiv [Typ] 0 Naphthalin Halbstoff [Typ] Kenaf Kenaf Fasermenge [kg] 7,00 7,00 H2O [kg] 92,072 92,072 NaOH 100%-ig [kg] 0,088 0,088 pH 10,8 10,8 Natriumsilikat [kg] 0,140 0,140 Temperatur [°C] 70 70 Bleichdauer [h] 3,0 3,0 H2O235%-ig [kg] 0,700 0,700 Versuch 2 Additiv [Typ] 0 Naphthalin Halbstoff [Typ] Abaca Abaca Fasermenge [kg] 7,00 7,00 H2O [kg] 92,072 92,072 NaOH 100%-ig [kg] 0,088 0,088 pH 10,9 10,9 Natriumsilikat [kg] 0,140 0,140 Temperatur [°C] 70 70 Bleichdauer [h] 3,0 3,0 H2O235%-ig [kg] 0,700 0,700 Versuch 3 Additiv [Typ] 0 Antrachinon Halbstoff [Typ] Kenaf Kenaf Fasermenge [kg] 7,00 7,00 H2O [kg] 92,072 92,072 NaOH 100%-ig [kg] 0,088 0,088 pH 10,8 10,8 Natriumsilikat [kg] 0,140 0,140 Temperatur [°C] 70 70 Bleichdauer [h] 3,0 3,0 H2O235%-ig [kg] 0,700 0,700 Versuch 4 Additiv [Typ] 0 Antrachinon Halbstoff [Typ] Abaca Abaca Fasermenge [kg] 7,00 7,00 H2O [kg] 92,072 92,072 NaOH 100%-ig [kg] 0,088 0,088 pH 11,0 11,0 Natriumsilikat [kg] 0,140 0,140 Temperatur [°C] 70 70 Bleichdauer [h] 3,0 3,0 H2O235%-ig [kg] 0,700 0,700 In Example 1, unbleached cellulose made from kenaf or abaca fibers was used as the pulp. The pulp suspension was adjusted to the desired consistency, adjusted to the desired pH with NaOH, buffered with sodium silicate, heated and mixed with H 2 O 2 as a bleaching chemical. Naphthalene or antrachinone was used as an additive in an amount of 0.2% additive per kg of absolutely dry fibers. The compositions of the bleaching liquors used are given below: Trial 1 Additive [type] 0 naphthalene Pulp [type] Kenaf Kenaf Amount of fibers [kg] 7.00 7.00 H 2 O [kg] 92,072 92,072 NaOH 100% [kg] 0.088 0.088 pH 10.8 10.8 Sodium silicate [kg] 0.140 0.140 Temperature [° C] 70 70 Bleaching time [h] 3.0 3.0 H 2 O 2 35% [kg] 0.700 0.700 Trial 2 Additive [type] 0 naphthalene Pulp [type] Abaca Abaca Amount of fibers [kg] 7.00 7.00 H 2 O [kg] 92,072 92,072 NaOH 100% [kg] 0.088 0.088 pH 10.9 10.9 Sodium silicate [kg] 0.140 0.140 Temperature [° C] 70 70 Bleaching time [h] 3.0 3.0 H 2 O 2 35% [kg] 0.700 0.700 Trial 3 Additive [type] 0 Antrachinone Pulp [type] Kenaf Kenaf Amount of fibers [kg] 7.00 7.00 H 2 O [kg] 92,072 92,072 NaOH 100% [kg] 0.088 0.088 pH 10.8 10.8 Sodium silicate [kg] 0.140 0.140 Temperature [° C] 70 70 Bleaching time [h] 3.0 3.0 H 2 O 2 35% [kg] 0.700 0.700 Trial 4 Additive [type] 0 Antrachinone Pulp [type] Abaca Abaca Amount of fibers [kg] 7.00 7.00 H 2 O [kg] 92,072 92,072 NaOH 100% [kg] 0.088 0.088 pH 11.0 11.0 Sodium silicate [kg] 0.140 0.140 Temperature [° C] 70 70 Bleaching time [h] 3.0 3.0 H 2 O 2 35% [kg] 0.700 0.700

Nach Ablauf der Bleiche wurde kein freies H2O2 mehr festgestellt, d.h. das gesamte H2O2 war während des Bleichprozesses verbraucht worden. Dabei wurden die folgenden Ergebnisse erhalten: Ergebnisse Versuch 1 ohne Additiv mit Additiv Weiße (%) 63,0 63,4 Viskosität (dm3/kg) 513 610 Versuch 2 ohne Additiv mit Additiv Weiße (%) 80,0 80,3 Viskosität (dm3/kg) 1273 1520 Versuch 3 ohne Additiv mit Additiv Weiße (%) 69,3 70,1 Viskosität(dm3/kg) 683 759 Versuch 4 ohne Additiv mit Additiv Weiße (%) 81,4 81,2 Viskosität (dm3/kg) 1463 1787 After the bleaching, no free H 2 O 2 was found, ie all of the H 2 O 2 had been consumed during the bleaching process. The following results were obtained: Results Trial 1 without additive with additive Whiteness (%) 63.0 63.4 Viscosity (dm 3 / kg) 513 610 Trial 2 without additive with additive Whiteness (%) 80.0 80.3 Viscosity (dm 3 / kg) 1273 1520 Trial 3 without additive with additive Whiteness (%) 69.3 70.1 Viscosity (dm 3 / kg) 683 759 Trial 4 without additive with additive Whiteness (%) 81.4 81.2 Viscosity (dm 3 / kg) 1463 1787

Die Viskositätsmessungen wurden dabei mit Hilfe des oben beschriebenen Kapillarviskosimeters durchgeführt. Es zeigte sich, daß in allen Fällen bei Mitverwendung der Additive ein deutlich niedrigerer Viskositätsabfall bei vergleichbarem Weißegrad erreicht wurde. Diese positive Wirkung läßt sich, wie im Beispiel gezeigt wird, sowohl mit Hart- als auch mit Weichfasern erreichen.The viscosity measurements were carried out using the method described above Capillary viscometer performed. It was found, that in all cases when using the additives a clear Lower viscosity drop achieved with comparable whiteness has been. This positive effect can be, as in the example is shown with both hard and soft fibers.

Beispiel 2Example 2

Um zu zeigen, daß kein Einfluß des Kochprozesses auf das erfindungsgemäße Bleichverfahren vorhanden ist, wurde ungebleichter Halbstoff aus einem alkalischen Antrachinon-Verfahren und ungebleichter Halbstoff aus einem Neutralsulfit-Antrachinon-Verfahren einem erfindungsgemäßen Bleichverfahren gemäß Beispiel 1 unterzogen. Dabei wurden die folgenden Ergebnisse erhalten: Ergebnisse Ungebl. Halbstoff [gekocht] Na + A.Q. Na + SO3 + A.Q. Additiv [Typ] 0 A.Q. 0 A.Q. Weiße [%] 72,1 71,8 73,2 73,8 Viskosität [dm3/kg] 740 884 621 811 In order to show that there is no influence of the cooking process on the bleaching process according to the invention, unbleached pulp from an alkaline antrachinone process and unbleached pulp from a neutral sulfite-antrachinone process were subjected to a bleaching process according to Example 1 according to the invention. The following results were obtained: Results Unblown Pulp [cooked] Na + AQ Na + SO3 + AQ Additive [type] 0 AQ 0 AQ White [%] 72.1 71.8 73.2 73.8 Viscosity [dm 3 / kg] 740 884 621 811

Es zeigt sich, daß der Kochprozeß keinen Einfluß auf das erfindungsgemäße Bleichverfahren besitzt.It turns out that the cooking process has no influence on the invention Bleaching process.

Claims (12)

Verfahren zur Reduzierung des Abbaus von Cellulose und Derivaten hiervon bei der Herstellung von gebleichten Spezialzellstoffen aus Einjahrespflanzen, dadurch gekennzeichnet, daß bei dem Bleichprozeß Additive zugefügt werden, die nicht mit dem Halbstoff, den Bleichchemikalien und anderen Komponenten der Bleichflotte reagieren, aber den Abbau von Cellulose und den Derivaten hiervon mindern.Processes to reduce cellulose and cellulose degradation Derivatives thereof in the manufacture of bleached specialty pulps from annual plants, characterized, that additives are added in the bleaching process that are not with the pulp, bleaching chemicals and other components of the bleaching liquor react, but the breakdown of cellulose and reduce the derivatives thereof. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß es sich bei den verwendeten Additiven um aromatische Kohlenwasserstoffe handelt.A method according to claim 1, characterized in that the additives used are aromatic hydrocarbons acts. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß es sich bei den verwendeten Additiven um Naphthalin oder Derivate hiervon handelt.A method according to claim 1 or 2, characterized in that that the additives used are naphthalene or derivatives thereof. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß es sich bei den verwendeten Additiven um Antrachinon oder Derivaten hiervon handelt.A method according to claim 1 or 2, characterized in that that the additives used are antrachinone or derivatives thereof. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß es sich um einen vollkommen chlorfreien Bleichprozeß handelt.Method according to one of the preceding claims, characterized characterized that it is a completely chlorine-free Bleaching process. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß es sich bei den Halbstoffen um Halbstoffe aus Hartfasern (wie z.B. Abaca, Sisal, usw.) handelt. Method according to one of the preceding claims, characterized characterized that it is in the semi-fabrics Pulp materials made from hard fibers (such as abaca, sisal, etc.) acts. Verfahren nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß es sich bei den Halbstoffen um Halbstoffe aus Weichfasern (wie z.B. Jute, Kenaf, usw.) handelt.Method according to one of claims 1 to 5, characterized characterized in that the pulps are pulps made of soft fibers (such as jute, kenaf, etc.). Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß 0,001 - 10 Gew.-% Additiv, bezogen auf die Masse an absolut trockenen Fasern, die in der Bleichflotte dispergiert werden soll, zugegeben werden.Method according to one of the preceding claims, characterized characterized in that 0.001-10% by weight additive, based on the mass of absolutely dry fibers in the bleaching liquor should be dispersed, added. Verfahren nach Anspruch 8, dadurch gekennzeichnet, daß 0,01 - 1 Gew.-% Additiv, bezogen auf die Masse an absolut trockenen Fasern, die in der Bleichflotte dispergiert werden soll, zugegeben werden.A method according to claim 8, characterized in that 0.01 - 1 wt .-% additive, based on the mass of absolute dry fibers that are dispersed in the bleaching liquor should be admitted. Verfahren nach Anspruch 9, dadurch gekennzeichnet, daß 0,05 - 0,55 Gew.-% Additiv, bezogen auf die Masse an absolut trockenen Fasern, die in der Bleichflotte dispergiert werden soll, zugegeben werden.A method according to claim 9, characterized in that 0.05 - 0.55 wt .-% additive, based on the mass of absolute dry fibers that are dispersed in the bleaching liquor should be admitted. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die Halbstoffe in einem Alkali-Antrachinon-Verfahren vor dem Bleichprozeß gekocht wurden.Method according to one of the preceding claims, characterized characterized in that the pulps in an alkali anthraquinone process were cooked before the bleaching process. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die Halbstoffe vor dem Bleichprozeß in einem Neutralsulfit-Antrachinon-Verfahren gekocht wurden.Method according to one of the preceding claims, characterized characterized in that the pulps before the bleaching process were cooked in a neutral sulfite-antrachinone process.
EP97108710A 1997-05-30 1997-05-30 Process for producing bleached special cellulose pulps Expired - Lifetime EP0881326B1 (en)

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DK97108710T DK0881326T3 (en) 1997-05-30 1997-05-30 Process for producing bleached special cellulose pulp
DE59704964T DE59704964D1 (en) 1997-05-30 1997-05-30 Process for the production of bleached special pulps
AT97108710T ATE207153T1 (en) 1997-05-30 1997-05-30 METHOD FOR PRODUCING BLEACHED SPECIAL PULP
EP97108710A EP0881326B1 (en) 1997-05-30 1997-05-30 Process for producing bleached special cellulose pulps
ES97108710T ES2164279T3 (en) 1997-05-30 1997-05-30 PROCEDURE FOR THE MANUFACTURE OF BLEACHED SPECIAL CELLS.
PT97108710T PT881326E (en) 1997-05-30 1997-05-30 PROCESS FOR THE PREPARATION OF BRANDED SPECIAL CELLS

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EP2751334A1 (en) * 2011-08-30 2014-07-09 Cargill, Incorporated Pulp composition

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Publication number Priority date Publication date Assignee Title
EP2751334A1 (en) * 2011-08-30 2014-07-09 Cargill, Incorporated Pulp composition
EP2751334A4 (en) * 2011-08-30 2015-04-22 Cargill Inc Pulp composition

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ES2164279T3 (en) 2002-02-16
EP0881326B1 (en) 2001-10-17

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