NO760666L - PROCEDURE FOR MAKING MECHANICAL MASSES. - Google Patents

PROCEDURE FOR MAKING MECHANICAL MASSES.

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Publication number
NO760666L
NO760666L NO760666A NO760666A NO760666L NO 760666 L NO760666 L NO 760666L NO 760666 A NO760666 A NO 760666A NO 760666 A NO760666 A NO 760666A NO 760666 L NO760666 L NO 760666L
Authority
NO
Norway
Prior art keywords
pulp
mass
mechanical
water
dried
Prior art date
Application number
NO760666A
Other languages
Norwegian (no)
Inventor
Nic Soteland
Original Assignee
Papirind Forskningsinst
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 Papirind Forskningsinst filed Critical Papirind Forskningsinst
Priority to NO760666A priority Critical patent/NO760666L/en
Priority to AT108277A priority patent/AT358917B/en
Priority to DE2707273A priority patent/DE2707273C2/en
Priority to CA272,600A priority patent/CA1103413A/en
Priority to AU22615/77A priority patent/AU510167B2/en
Priority to SE7702073A priority patent/SE439938B/en
Priority to FR7705694A priority patent/FR2342366A1/en
Priority to IT12482/77A priority patent/IT1072075B/en
Priority to BE175244A priority patent/BE851814A/en
Priority to DK86477A priority patent/DK86477A/en
Priority to FI770625A priority patent/FI70442B/en
Priority to GB8113/77A priority patent/GB1572519A/en
Priority to JP2040077A priority patent/JPS52124901A/en
Priority to NL7702142A priority patent/NL7702142A/en
Publication of NO760666L publication Critical patent/NO760666L/en

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00—Fibrous raw materials or their mechanical treatment
    • D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
    • D21B1/12—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
    • D21B1/14—Disintegrating in mills
    • D21B1/16—Disintegrating in mills in the presence of chemical agents
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00—Fibrous raw materials or their mechanical treatment
    • D21B1/38—Conserving the finely-divided cellulosic material
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
    • D21F11/00—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
    • D21F11/14—Making cellulose wadding, filter or blotting paper

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Pressure Sensors (AREA)
  • Air Bags (AREA)

Description

Fremgangsmåte ved fremstilling av mekaniske masser.Procedure for the production of mechanical masses.

Fpreliggende oppfinnelse vedrorer en fremgangsmåte ved fremstilling av mekaniske masser. The present invention relates to a method for the production of mechanical masses.

Mekaniske masser er en fellesbetegnelse for massetyper erholdt ved mekanisk defibrering av forskjellige treslag, eksempelvis ved hjelp av slipestener eller skiveraffinorer, eventuelt etter en^mild kjemikaliebehandling. Mechanical pulp is a general term for types of pulp obtained by mechanical defibration of different types of wood, for example with the help of grinding stones or disc refiners, possibly after a mild chemical treatment.

Da mekanisk masse er et relativt rimelig produkt sammenlignet med cellulosemasser erholdt ved en kjemisk oppslutning av ved, har slike masser fått en bred anvendelse som råstoff ved fremstilling av avispapir, magasinpapir o.l. Imidlertid utviser As mechanical pulp is a relatively inexpensive product compared to cellulose pulps obtained by chemical digestion of wood, such pulps have been widely used as raw material in the production of newsprint, magazine paper etc. However, expelling

massen den uheldige egenskap at den undergår "selvliming" ved lagring, og som folge av denne "selvlimingen" vil mekanisk masse etter lagring utvise mer eller mindre hydrofobe egenskaper, avhengig av lagringstid, harpiksinnhold, lagringsforhold etc, the pulp has the unfortunate property that it undergoes "self-gluing" during storage, and as a result of this "self-gluing", mechanical pulp will exhibit more or less hydrophobic properties after storage, depending on storage time, resin content, storage conditions, etc.

hvilket kan gjore en videre håndtering av en slik masse vanske-lig når denne skal videreforedles. which can make further handling of such a mass difficult when it is to be further processed.

På grunn av "selvliming" har mekanisk masse således kun i be-skjeden grad blitt anvendt for absorpsjonsformål, eksempelvis i bleier, damebind, tamponger, håndklær og lignende produkter, for hvilke formål hoyforedlede, blekede celluloser stort sett har vært enerådende. Because of "self-gluing", mechanical pulp has thus only been used to a modest extent for absorption purposes, for example in nappies, sanitary napkins, tampons, towels and similar products, for which purposes highly refined, bleached celluloses have largely been predominant.

Hvis harpiksen kan fjernes fra den mekaniske masse, har det vist seg at mekanisk masse med fordel også kan anvendes for de ovenfor nevnte formål, slik som angitt i norsk patent nr. 124.193. Ifolge dette patent kan harpiksen fjernes fra massen eksempelvis ved ekstraksjon med aceton, hvorved det erholdes et produkt med gode absorpsjonsegenskaper. Imidlertid er en industriell eks- tråksjonsprosess en relativt komplisert og fordyrende prosess som krever stor kapitalinvestering i ekstraksjonsutstyr, gjen-vinningsutstyr etc. Aceton-ekstrahering av mekanisk masse har også tidligere vært foreslått for å forbedre den mekaniske masses styrkeegenskaper og for å gjore massen lettere oppslagbar i den etterfølgende foredlingsprosess (Brandal & Lindheim, Pump & Paper Mag. Can. 67 T 431, 1966) . If the resin can be removed from the mechanical pulp, it has been shown that mechanical pulp can advantageously also be used for the above-mentioned purposes, as stated in Norwegian patent no. 124,193. According to this patent, the resin can be removed from the mass, for example by extraction with acetone, whereby a product with good absorption properties is obtained. However, an industrial extraction process is a relatively complicated and expensive process that requires a large capital investment in extraction equipment, recycling equipment, etc. Acetone extraction of mechanical pulp has also previously been proposed to improve the mechanical pulp's strength properties and to make the pulp easier to turn up. in the subsequent refining process (Brandal & Lindheim, Pump & Paper Mag. Can. 67 T 431, 1966).

I norsk ansokning nr. 74.3286 er det beskrevet en fremgangsmåte ved behandling av en mekanisk masse slik at den ved aldring bibeholder sine opprinnelige hydrofile egenskaper. En mekanisk masse behandlet i henhold til norsk ans. nr. 74.3286 vil ved lagring forbli hydrofil og således lett å slå opp ved den etter-følgende foredling. Det har ytterligere vist seg at en slik masse er utmerket egnet for absorpsjonsformål til tross for at den nye behandlingsmåte bare i liten grad påvirker den mekaniske masses harpiksinnhold. In Norwegian application no. 74.3286, a method is described for treating a mechanical pulp so that it retains its original hydrophilic properties during aging. A mechanical pulp processed in accordance with Norwegian ans. No. 74.3286 will remain hydrophilic when stored and thus easy to break up during the subsequent processing. It has further been shown that such a pulp is excellently suitable for absorption purposes despite the fact that the new treatment method only slightly affects the resin content of the mechanical pulp.

Ifolge ans. nr. 74.3286 behandles eller impregneres en mekanisk masse med en buffer som bufrer i pH-området 6-10, fortrinnsvis According to ans. no. 74.3286, a mechanical mass is treated or impregnated with a buffer that buffers in the pH range 6-10, preferably

7-9. Egnede buffere er alkalimetall-salter og ammoniumsalter av eksempelvis fosforsyre, karbonsyre, sitronsyre, vinsyre etc. 7-9. Suitable buffers are alkali metal salts and ammonium salts of, for example, phosphoric acid, carbonic acid, citric acid, tartaric acid, etc.

Bufferen tilsettes den mekaniske masse, fortrinnsvis i form av en vandig opplosning og i en slik mengde at den mekaniske masse tilfores minst 0,2 vekts-% regnet på massens torrvekt, fortrinnsvis 0,-5% eller mer. The buffer is added to the mechanical pulp, preferably in the form of an aqueous solution and in such a quantity that the mechanical pulp is supplied with at least 0.2% by weight calculated on the dry weight of the pulp, preferably 0.5% or more.

En slik behandling av den mekaniske masse med en vandig opplosning av bufferen er meget billig og enkel å utfore. Tilsetningen kan skje på flere steder under fremstilling av den mekaniske masse, avhengig av produktets bruksområde og tilgjengelig utstyr. Tilsetningen kan eksempelvis skje under massefremstilling i raf-finor eller slipestol, i papirmaskinens bakvannssystem, i lim-pressen, ved påsproytning under eller etter arkdannelsen, inn-sprøytning i massen for denne eventuelt omdannes til masseballer. Denne behandlingsmåte kan således utfores med tilgjengelig utstyr og kan således tillempes i allerede eksisterende produksjons-anlegg. Ved den nye fremgangsmåte vil man eksempelvis kunne fremstille absorberende materialer fra mekaniske masser, hvilket betyr vesentlige besparelser vis-a-vis hoyforedlede celluloseprodukter. Sett fra et.ressurs- og miljomessig hensyn representerer frem-gangsmåten store selvinnlysende fordeler. Such treatment of the mechanical mass with an aqueous solution of the buffer is very cheap and easy to carry out. The addition can take place in several places during the production of the mechanical pulp, depending on the product's area of use and available equipment. The addition can, for example, take place during pulp production in refiners or sanding chairs, in the paper machine's waste water system, in the glue press, by spraying during or after sheet formation, injection into the pulp before it is eventually converted into pulp balls. This method of treatment can thus be carried out with available equipment and can thus be applied in already existing production facilities. With the new method, it will be possible, for example, to produce absorbent materials from mechanical masses, which means significant savings vis-à-vis highly refined cellulose products. Seen from a resource and environmental perspective, the procedure represents major self-evident advantages.

Det har nu overraskende vist seg at det er mulig å fremstille en mekanisk masse som bibeholder de hydrofile egenskaper uten å foreta den efterfolgende bufferbehandling av massen, slik som beskrevet i norsk ansokning nr. 74. 3286. Ifolge den nye fremgangsmåte dannes det onskede buffersystem i massen in situ. Ved å avpasse en eventuell etterbehandling av massen kan dette buffersystem bibeholdes, slik at massen under lagring ikke undergår "selvliming" og således bibeholder de hydrofile egenskaper . It has now surprisingly been shown that it is possible to produce a mechanical mass which retains the hydrophilic properties without carrying out the subsequent buffer treatment of the mass, as described in Norwegian application no. 74. 3286. According to the new method, the desired buffer system is formed in the mass in situ. By adapting any post-treatment of the pulp, this buffer system can be maintained, so that the pulp does not undergo "self-gluing" during storage and thus retains its hydrophilic properties.

Som ovenfor nevnt kan mekaniske masser fremstilles på flere måter og kan også underkastes lette kjemikaliebehandlinger. Slike behandlinger kan omfatte en forbehandling av flisen med sulfittopplosninger, innsproyting av sulfitt og blekekjemikalier i raffinoren, eller massen kan efter defibrering underkastes As mentioned above, mechanical masses can be produced in several ways and can also be subjected to light chemical treatments. Such treatments may include a pre-treatment of the chips with sulphite solutions, injection of sulphite and bleaching chemicals into the refiner, or the pulp may, after defibration, be subjected to

en konvensjonell bleking i bleketårn. Ved flere av disse behandlinger ligger pH i området 7-11, og da prosesstemperaturen a conventional bleaching in a bleaching tower. In several of these treatments, the pH is in the range 7-11, and then the process temperature

samtidig kan ligge i området 50-150°C, vil det dannes organiske syrer på basis av vedens lignin. og karbohydratinnhold. at the same time can be in the range 50-150°C, organic acids will be formed on the basis of the wood's lignin. and carbohydrate content.

Disse syrer kan sammen med natriumhydroksyd fra sulfittbe-handlingen eller peroksydblekingen (ditionittbleking) danne bufférsystemer, som bufrer i området pH 7-10. Disse buffer-systemer oppstår således som biprodukter i massen som folge av de ovenfor nevnte milde kjemiske behandlinger. Together with sodium hydroxide from the sulphite treatment or peroxide bleaching (dithionite bleaching), these acids can form buffer systems, which buffer in the pH range 7-10. These buffer systems thus arise as by-products in the mass as a result of the above-mentioned mild chemical treatments.

Alle mekaniske massetyper som idag underkastes en slik mild kjemisk behandling blir efterbehandlet ved vasking med vann og pH blir justert med svovelsyre eller svoveldioksyd til pH 5-5,5. All mechanical pulp types that are currently subjected to such a mild chemical treatment are post-treated by washing with water and the pH is adjusted with sulfuric acid or sulfur dioxide to pH 5-5.5.

Den efterfolgende pH-justering av den mekaniske masse til pH 5-5,5 vil folgelig forskyve massens pH fra det onskete område The subsequent pH adjustment of the mechanical pulp to pH 5-5.5 will consequently shift the pH of the pulp from the desired range

på 6-10, fortrinnsvis 7-9, hvorfor massen efter pH-justering ikke lenger vil bibeholde de hydrofile egenskaper efter aldring. of 6-10, preferably 7-9, which is why the mass after pH adjustment will no longer retain the hydrophilic properties after ageing.

Konvensjonell peroksydbleking av mekanisk masse utfores i dag ved at massen behandles i 2-3 timer ved 50-70°C med en blanding av NaOH, ^ 2G2 °9 vannglass og ved en massekonsistens i området 10-20%. Ved blekeprosessens begynnelse er pH 10-11, mens den efter bleking ligger i området 8-9. Conventional peroxide bleaching of mechanical pulp is carried out today by treating the pulp for 2-3 hours at 50-70°C with a mixture of NaOH, ^ 2G2 °9 glass of water and at a pulp consistency in the range of 10-20%. At the beginning of the bleaching process, the pH is 10-11, while after bleaching it is in the range of 8-9.

Efter den konvensjonelle fremstillingsmetode vil massen efter bleking fortynnes med vann, og pH justeres til ca. 5 med svovelsyre eller svoveldioksyd, hvorefter den avsuges og vaskes med vann. According to the conventional production method, the pulp will be diluted with water after bleaching, and the pH will be adjusted to approx. 5 with sulfuric acid or sulfur dioxide, after which it is suctioned off and washed with water.

Denne fremgangsmåte vil fortsatt være aktuell når massen skal anvendes til ikke-absorberende formål. Skal imidlertid massen anvendes til absorberende formål, eksempelvis til fluffede produkter, tissue-produkter og lignende, må én. eventuell pH justering utfores slik at massens pH ikke senkes til 5-5,5 This procedure will still be relevant when the mass is to be used for non-absorbent purposes. However, if the mass is to be used for absorbent purposes, for example for fluffy products, tissue products and the like, one must. any pH adjustment is carried out so that the pH of the mass is not lowered to 5-5.5

i henhold til konvensjonell fremgangsmåte.according to conventional procedure.

Buffersystemene som er dannet i massen som folge av den milde kjemiske behandling kan bibeholdes ved at man eventuelt full-stendig utelater en efterfolgende vaskebehandling, eller at The buffer systems that are formed in the pulp as a result of the mild chemical treatment can be maintained by completely omitting a subsequent washing treatment, or

vaskebehandlingen kun foretas med vann som eventuelt er svakt alkalisk, eiler hvis det er onskelig å senke massens pH til et the washing treatment is only carried out with water that is possibly weakly alkaline, or if it is desirable to lower the pH of the mass to a

foretrukket område kan dette utfores ved anvendelse av egnede, svake syrer, slik at den vaskede masses pH ligger i området 7-8,5. Anvendes eksempelvis fosforsyre, karbondioksyd, sitronsyre eller vinsyre kan massens innhold av buffersystem forokes hvis dette anses for gunstig. preferred range, this can be carried out by using suitable, weak acids, so that the pH of the washed mass is in the range 7-8.5. If, for example, phosphoric acid, carbon dioxide, citric acid or tartaric acid is used, the mass's content of buffer system can be increased if this is considered beneficial.

Velger man således den riktige efterbehandling for en mekanisk masse som har vært underkastet en mild kjemisk behandling, kan man som ovenfor beskrevet erholde en mekanisk masse som inne-holder en egnet mengde buffer som bufrer i det onskede pH område på 6-10, fortrinnsvis i området 7-9, hvorved den erholdte masse vil forbli hydrofil og ikke undergå "selvliming" ved aldring. Thus, if one chooses the right post-treatment for a mechanical pulp that has been subjected to a mild chemical treatment, one can, as described above, obtain a mechanical pulp that contains a suitable amount of buffer that buffers in the desired pH range of 6-10, preferably in the range 7-9, whereby the mass obtained will remain hydrophilic and will not undergo "self-gluing" when aging.

Den onskede effekt kan også oppnås ved konvensjonell sliping i en slipestol, hvis sproytevannets pH holdes i det alkaliske området. Dette kan eksempelvis utfores ved å anvende som sproyte-vann vaskevann fra en peroksyd-blekning. The desired effect can also be achieved by conventional grinding in a grinding chair, if the pH of the spray water is kept in the alkaline range. This can be done, for example, by using washing water from a peroxide bleach as spray water.

Den mekaniske masse inneholdende det in situ dannede buffer system kan torkes direkte på konvensjonell måte, eller det kan omformes til et onsket produkt, så som et tissue-produkt, hvori det i arkformningsmaskinen anvendes et bakvann som reagerer alkalisk. The mechanical pulp containing the in situ formed buffer system can be dried directly in a conventional way, or it can be transformed into a desired product, such as a tissue product, in which a backwater that reacts alkaline is used in the sheet forming machine.

Oppfinnelsen illustreres ved de efterfolgende eksempler.The invention is illustrated by the following examples.

Det ble fremstilt forskjellige mekaniske masser som ble undersokt med hensyn til vannabsorpsjonsegenskaper. Efter frem-stillingen ble massene torket i en syklon og fluffet (i en Wenneberg-kvern). De fluffede masser ble deretter kunstig altret ved 105°C i en time, hvoretter massen fikk henstå i 30-60 min. ved romtemperatur for den eldete massens vannabsorpsjon ble bestemt. Vannabsorpsjonen for ikke-eldet masse og for masse som ikke var fremstilt i henhold til foreliggendeOppfinnelse ble også bestemt. Different mechanical masses were prepared and investigated with regard to water absorption properties. After preparation, the masses were dried in a cyclone and fluffed (in a Wenneberg mill). The fluffed masses were then artificially sacrificed at 105°C for one hour, after which the mass was allowed to rest for 30-60 min. at room temperature for the water absorption of the aged pulp was determined. The water absorption for unaged pulp and for pulp not prepared according to the present invention was also determined.

Bestemmelse av vannabsorpsjons-hastigheten ble ved disse Determination of the water absorption rate was by these

forsok utfort ved at 10 g lufttorr, fluffet masse fordeles jevnt i et metallnett (metallkurv med dimensjonene 7 cm x 20 cm experiment by distributing 10 g of air-dry, fluffed mass evenly in a metal net (metal basket with dimensions 7 cm x 20 cm

x 1 cm) som ble plassert i en beholder inneholdende 200 ml vann. Den tid det tar fra det oyeblikk metallnettet plasseres i beholderen og til all masse er gjennomfuktet med vann er et mål for massens vannabsorpsjonshastighet. x 1 cm) which was placed in a container containing 200 ml of water. The time it takes from the moment the metal mesh is placed in the container until all the mass is soaked with water is a measure of the mass's water absorption rate.

EKSEMPEL 1EXAMPLE 1

Det ble fremstilt en raffinormasse ved at 25 kg granflis fikk ligge natten over i 220 1 av en vandig 10% Na SO opplosning (pH 8,6) i 12 timer ved 20 oC. Den.impregnerte flis ble deretter raffinert i en skiveraffinor med et kraftforbruk på 800 kWt/tonn. En del av den således erholdte masse (i det efterfolgende betegnet med la) ble torket og absorpsjonstiden for og etter aldring bestemt. A raffinor mass was produced by allowing 25 kg of spruce chips to lie overnight in 220 1 of an aqueous 10% Na SO solution (pH 8.6) for 12 hours at 20 oC. The impregnated chips were then refined in a disc refiner with a power consumption of 800 kWt/ton. A part of the mass thus obtained (in the following denoted by 1a) was dried and the absorption time before and after aging was determined.

En del av massen ble godt utvasket med vann (masse lb) og deretter torket og vannabsorpsjonen ble bestemt. Part of the pulp was well washed with water (mass lb) and then dried and the water absorption was determined.

Ytterligere en del av massen ble vasket med S02vann (masse lc) slik at massens pH ble 5,5, hvoretter massen ble torket og vannabsorpsjonen bestemt. A further part of the mass was washed with SO 2 water (mass 1c) so that the pH of the mass became 5.5, after which the mass was dried and the water absorption determined.

Resultatene fremgår av den efterfolgende tabell.The results appear in the following table.

EKSEMPEL 2: Bleket masseEXAMPLE 2: Bleached pulp

Granslipmasse ble bleket til en lyshet på 73% ved 2% H20 2, 1,2% NaOH og 5% vannglass pH efter bleking var 8,5. Spruce pulp was bleached to a lightness of 73% with 2% H2O 2 , 1.2% NaOH and 5% water glass pH after bleaching was 8.5.

Massens pH efter bleking var 8,5, efter en mild vannvask var massens pH 7,5. Denne masse (2a) ble undersokt med hensynt til vannabsorpsjon, på samme måte som angitt ovenfor og resultatene er vist i den efterfolgende tabell. The pH of the pulp after bleaching was 8.5, after a mild water wash the pH of the pulp was 7.5. This mass (2a) was examined with regard to water absorption, in the same manner as indicated above and the results are shown in the following table.

En del av den blekede masse ble surgjort på konvensjonell måte med SC>2 vann til pH 5,5 og massens (2b) vannabsorpsjonsegenskaper bestemt som tidligere angitt og resultatene er vist i den efterfolgende tabell. A portion of the bleached pulp was acidified in a conventional manner with SC>2 water to pH 5.5 and the water absorption properties of the pulp (2b) determined as previously indicated and the results are shown in the following table.

For ordens skyld kan dec nevnes at absorpsjonshastigheten For the record, it may be mentioned that the absorption rate

for en gran-raffinormasse er for og efter aldring henholdsvis 8-14 og 90-600. for a spruce raffinor pulp before and after aging are 8-14 and 90-600 respectively.

Det kan av det ovenfor viste resultat klart sees at mekanisk masse fremstilt i henhold til foreliggende oppfinnelse resul-terer i masse med hoy absorpsjonshastighet, selv efter kunstig aldring i 1 time ved 105°C. It can be clearly seen from the result shown above that mechanical pulp produced according to the present invention results in pulp with a high absorption rate, even after artificial aging for 1 hour at 105°C.

Claims (4)

1. Fremgangsmåte ved fremstilling av mekanisk masse egnet for absorpsjonsformål, hvor ved-råstoffet for, under og/eller efter en mekanisk defibrering behandles med alkalisk reagerende bestanddeler og hvor den defibrerte masse torkes, eventuelt eliter arkforming, karakterisert ved at massen torkes i alkalisk bufret tilstand.1. Procedure for the production of mechanical pulp suitable for absorption purposes, where the wood raw material before, during and/or after a mechanical defibration is treated with alkaline-reactive components and where the defibrated pulp is dried, possibly eluting sheet formation, characterized by the pulp being dried in an alkaline buffer state. 2. Fremgangsmåte ifolge krav 1, karakterisert ved at den alkaliske massens pH justeres til pH 7-9 for torking.2. Method according to claim 1, characterized in that the pH of the alkaline mass is adjusted to pH 7-9 for drying. 3.F remgangsmåte ifolge krav 2, karakterisert ved at massens pH justeres med fosforsyre, karbonsyre, sitronsyre eller vinsyre, eller blandinger derav.3. Process according to claim 2, characterized in that the pH of the mass is adjusted with phosphoric acid, carbonic acid, citric acid or tartaric acid, or mixtures thereof. 4. Fremgangsmåte ifolge krav 1, karakterisert ved at massen blekes på i og for seg kjent måte under alkaliske betingelser, hvoretter massen torkes, eventuelt efter en pH-justering til 7-9.4. Method according to claim 1, characterized in that the mass is bleached in a manner known per se under alkaline conditions, after which the mass is dried, possibly after a pH adjustment to 7-9.
NO760666A 1976-02-27 1976-02-27 PROCEDURE FOR MAKING MECHANICAL MASSES. NO760666L (en)

Priority Applications (14)

Application Number Priority Date Filing Date Title
NO760666A NO760666L (en) 1976-02-27 1976-02-27 PROCEDURE FOR MAKING MECHANICAL MASSES.
AT108277A AT358917B (en) 1976-02-27 1977-02-17 METHOD FOR PRODUCING DRY, UNBLEACHED WOOD GRIND
DE2707273A DE2707273C2 (en) 1976-02-27 1977-02-19 Process in the production of wood pulp
CA272,600A CA1103413A (en) 1976-02-27 1977-02-24 Process for the manufacture of mechanical pulp
AU22615/77A AU510167B2 (en) 1976-02-27 1977-02-24 Mechanical pulp
SE7702073A SE439938B (en) 1976-02-27 1977-02-24 PROCEDURE FOR MANUFACTURING MECHANICAL MASS
FR7705694A FR2342366A1 (en) 1976-02-27 1977-02-25 MECHANICAL PULP MANUFACTURING PROCESS AND NEW PRODUCT THUS OBTAINED
IT12482/77A IT1072075B (en) 1976-02-27 1977-02-25 MECHANICAL PASTA MANUFACTURING PROCESS WITH HYDROPHILE CHARACTERISTICS
BE175244A BE851814A (en) 1976-02-27 1977-02-25 MECHANICAL DOUGH PREPARATION PROCESS
DK86477A DK86477A (en) 1976-02-27 1977-02-25 PROCEDURE FOR MAKING MECHANICAL MASSES
FI770625A FI70442B (en) 1976-02-27 1977-02-25 FREQUENCY REARING FOR MECHANICAL MASSAGE
GB8113/77A GB1572519A (en) 1976-02-27 1977-02-25 Process for the manufacture of mechanical pulp
JP2040077A JPS52124901A (en) 1976-02-27 1977-02-28 Process for making mechanical pulp
NL7702142A NL7702142A (en) 1976-02-27 1977-02-28 PROCESS FOR THE PREPARATION OF MECHANICAL CELLULOSE SEMI-MATERIAL.

Applications Claiming Priority (1)

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NO760666A NO760666L (en) 1976-02-27 1976-02-27 PROCEDURE FOR MAKING MECHANICAL MASSES.

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NO760666L true NO760666L (en) 1977-08-30

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NO760666A NO760666L (en) 1976-02-27 1976-02-27 PROCEDURE FOR MAKING MECHANICAL MASSES.

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JP (1) JPS52124901A (en)
AT (1) AT358917B (en)
AU (1) AU510167B2 (en)
BE (1) BE851814A (en)
CA (1) CA1103413A (en)
DE (1) DE2707273C2 (en)
DK (1) DK86477A (en)
FI (1) FI70442B (en)
FR (1) FR2342366A1 (en)
GB (1) GB1572519A (en)
IT (1) IT1072075B (en)
NL (1) NL7702142A (en)
NO (1) NO760666L (en)
SE (1) SE439938B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE8002027L (en) * 1980-03-14 1981-09-15 Sunds Defibrator IN CONNECTION WITH THE MANUFACTURE OF THERMOMECHANICAL MASS IMPROVING ITS ABSORPTION PROPERTIES
AU5088885A (en) * 1985-11-29 1987-06-04 Gippsland Institute of Advanced Education, The The production of hard compact carbonaceous material through water/acid/alkali treatment
US4976819A (en) * 1988-04-28 1990-12-11 Potlatch Corporation Pulp treatment methods

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2454534A (en) * 1940-08-03 1948-11-23 Wood Conversion Co Process for defibering lignocellulose while subjected to steam and alkali-metal hydroxide
FR1199065A (en) * 1958-06-10 1959-12-11 Saint Gobain Further refining of pulp
US3186899A (en) * 1962-09-11 1965-06-01 Minnesota And Outario Paper Co Groundwood pulp
BE792031A (en) * 1971-12-14 1973-03-16 Mo Och Domsjoe Ab PROCESS FOR THE PREPARATION OF MECHANICAL PULPS
NO136583C (en) * 1974-09-12 1984-06-07 Papirind Forskningsinst MECHANICAL TRIMASSES WITH HIGH SPEED OF ABSORPTION, AND PROCEDURE FOR PREPARING THEREOF

Also Published As

Publication number Publication date
FR2342366B1 (en) 1982-03-05
NL7702142A (en) 1977-08-30
JPS52124901A (en) 1977-10-20
GB1572519A (en) 1980-07-30
DE2707273C2 (en) 1984-01-26
BE851814A (en) 1977-06-16
FI770625A (en) 1977-08-28
SE7702073L (en) 1977-08-28
ATA108277A (en) 1980-02-15
IT1072075B (en) 1985-04-10
DK86477A (en) 1977-08-28
SE439938B (en) 1985-07-08
DE2707273A1 (en) 1977-09-01
FI70442B (en) 1986-03-27
AU2261577A (en) 1978-08-31
FR2342366A1 (en) 1977-09-23
AU510167B2 (en) 1980-06-12
CA1103413A (en) 1981-06-23
AT358917B (en) 1980-10-10

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