EP2122053B1 - Tracing paper production method - Google Patents

Tracing paper production method Download PDF

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Publication number
EP2122053B1
EP2122053B1 EP07871997.8A EP07871997A EP2122053B1 EP 2122053 B1 EP2122053 B1 EP 2122053B1 EP 07871997 A EP07871997 A EP 07871997A EP 2122053 B1 EP2122053 B1 EP 2122053B1
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Prior art keywords
paper
pulp
suspension
aqueous
sheet
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German (de)
French (fr)
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EP2122053A2 (en
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David Botterill
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ArjoWiggins SAS
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ArjoWiggins SAS
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    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
    • D21H27/06—Vegetable or imitation parchment; Glassine paper
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/005—Microorganisms or enzymes

Definitions

  • paper pulps must undergo a refining step in order to hydrate and fibrillate the fibers.
  • This step densifies the fibrous mat forming on the web of the paper machine and controls the physical and optical characteristics of the paper sheet.
  • this refining step is pushed to obtain a very dense sheet almost free of air (voids), which gives transparency to the paper.
  • the dewatering time can be quite long compared to the dewatering time of a poorly refined dough (to make a conventional non-transparent paper).
  • the present invention aims to solve the disadvantages of the prior art of the manufacture of a tracing paper, in particular to reduce the energy costs of this manufacture while maintaining good mechanical and optical characteristics of the tracing paper.
  • the invention thus provides a method for manufacturing a sheet of tracing paper having good mechanical characteristics and a low opacity index, the pulp of which is based on virgin cellulosic fibers in aqueous suspension is subjected to the action of an enzyme preparation based on cellulases prior to mechanical refining.
  • a tracing paper is manufactured which can have an opacity index of less than 30%, measured according to the ISO 2469 standard.
  • the fibrous composition of the paper pulp according to the invention may comprise at least 50% of virgin cellulosic fibers in dry weight, preferably at least 70% of virgin cellulosic fibers in dry weight, relative to to the total dry weight of the fibrous composition of the pulp. More preferably still the composition may comprise 100% virgin fibers.
  • fibers in the sense of the present invention, as usually used in the paper industry, non-recycled fibers, these fibers may in addition come from broken manufacturing.
  • Broken manufacturing is paper removed at any stage of manufacture on the paper machine and generally pulped.
  • wet manufacturing breaks that is to say accumulated in the wet part of the paper machine
  • dry manufacturing breaks accumulated at any point of the dryness of the machine. paper machine, trimmings from winding, re-slitting and cutting operations as well as paper rejected in sorting.
  • step a) The enzymatic action in step a) is performed on the pulp at the required pH and temperature conditions for the enzymes to be active, according to the knowledge in the field of biotechnology.
  • the enzymatic preparation of the invention uses endo-1,4- ⁇ -glucanase-type cellulases, which are commonly referred to as “endoglucanases”.
  • the pulp is added to the paper pulp composed of at least 50% of virgin cellulosic fibers in aqueous suspension at a rate of 50 g / l, the enzyme preparation containing the cellulases.
  • 0.05 to 1 gram of a cellulase, in particular of endoglucanase type is added to said aqueous suspension based on virgin cellulosic fibers per kilogram of paper pulp on a dry weight basis, and the whole is mixed for a time not exceeding 60 minutes.
  • step a) of the process does not require to be continued beyond 60 minutes.
  • the enzymatic reaction of the cellulases is therefore stopped, preferably by inhibiting it by addition of a chemical inhibitor to the pulp suspension.
  • step b) of the process of the invention the enzymatic action of the cellulases is inhibited by adding to said aqueous suspension of paste a chemical inhibitor so that the enzymatic treatment time of said aqueous suspension of dough does not exceed 60 minutes.
  • said chemical inhibitor is a strong oxidizer. More particularly, said chemical inhibitor is chosen from sodium hypochlorite and hydrogen peroxide, especially used in the form of an aqueous solution.
  • One method to determine that enzyme inhibition has occurred is to track the viscosity of CMC (carboxymethylcellulose) solutions made with the water of dough samples taken before and after the addition of the inhibitor, according to the method described later after the examples.
  • CMC carboxymethylcellulose
  • the CMC solution for the sample taken before the addition of the inhibitor quickly loses its viscosity due to the action of the enzymes on the cellulose chains whereas the CMC solution relative to the sample taken after the addition of the inhibitor (once brought to the activity temperature of the enzymes) remains stable in viscosity.
  • This method makes it possible to optimize the concentration and quantity of the inhibitor as well as the inhibition time.
  • the pulp thus treated, resulting from step b) of the process is subjected according to step c) of the process of the invention to a mechanical refining.
  • the mechanical refining is carried out by means of refiner (s).
  • the paper pulp is refined to a Schöpper-Riegler degree greater than 80.
  • step d) of the process of the invention the aqueous pulp suspension obtained is deposited on the fabric of a paper machine, generally a flat-bed paper machine, and the water is drained by gravity and by means of foils and other dewatering devices.
  • Step d) of the tracing paper manufacturing method according to the invention is characterized by an improvement in the drip rate of the dough on the fabric of the paper machine compared to the same dough not treated with enzymes.
  • the dewatering speed of the aqueous pulp suspension obtained at the end of stage c) of the process is characterized by a dewatering time determined according to the test described below in the paragraph "DESCRIPTION AND CONDITIONS OF REALIZATION OF THE MEASURING DRAINAGE "for a given volume, between 40 and 60 seconds.
  • the dewatering speed of said processed and refined pulp which is characterized by a dewatering time determined according to the test described below in the paragraph "DESCRIPTION AND CONDITIONS OF REALIZATION OF THE SEGMENT MEASUREMENT" for a given volume, can be improved by at least 10% with respect to the dewatering speed of a paste that has not been previously treated enzymatically, but refined so as to obtain a tracing paper of opacity value identical, said dewatering speed being characterized by a dewatering time determined according to the same test described below in the paragraph "DESCRIPTION AND CONDITIONS OF REALIZATION OF THE MEASUREMENT OF DRAINAGE".
  • the temperature of the dough in suspension can be adjusted to a temperature of less than or equal to 80 ° C., preferably between 70 and 75 ° C., and the dripping speed on the fabric of the paper machine of the dough resulting from step d) remains significantly improved.
  • This decrease in the temperature of the pulp suspension as well as the reduction of the pulp refining energy represents an energy gain.
  • the refined paste obtained at the end of step c) is heated to said temperature, in the short circuit of the paper machine leading to the headbox of the machine paper.
  • step e) of the process of the invention the sheet of tracing paper obtained in step d) of the process is dried on drying rollers.
  • the sheet of tracing paper thus obtained has a relatively low opacity index specific to the tracing paper sheets, more specifically an opacity index of less than 40%, preferably less than 30%, measured according to the ISO 2469 standard.
  • the fiber suspension is at a temperature of about 50 ° C and its pH was adjusted to between 6 and 8 to be in the enzyme activation conditions.
  • the pulp suspension is refined in a mechanical refiner by applying a refining energy of 500 kWh / ton so as to obtain a level of fibrillation leading to a final opacity of the paper sheet of 36%.
  • the sheet of tracing paper thus obtained is dried on drying rollers at about 100 ° C.
  • the figure 2 represents the influence of enzymatic treatment on the dewatering time (Dv).
  • the tracing paper manufacturing method according to the invention makes it possible to improve the dripping speed of the dough on the fabric of the paper machine, the dripping speed of the dough which is characterized by a time of dyeing. draining determined according to the test described below in the paragraph "DESCRIPTION AND CONDITIONS FOR PERFORMING THE MEASUREMENT OF DRAINAGE" for a given volume.
  • the dewatering time (in seconds) determined according to the same test described below a sheet of tracing paper obtained according to the same process as that of the invention but whose pulp in aqueous suspension is free of any enzymatic treatment according to Example 2 for a refining energy of 800 kWh / ton, is 95 s.

Description

La présente invention concerne un procédé de fabrication d'un papier calque à partir d'une composition de fibres cellulosiques incluant une étape de traitement enzymatique des fibres.The present invention relates to a method of manufacturing a tracing paper from a cellulosic fiber composition including a step of enzymatic treatment of fibers.

On désigne par « papier calque », au sens de la présente invention et traditionnellement dans l'industrie papetière, un papier calque dit « naturel » obtenu à partir d'une suspension aqueuse de pâte papetière ayant subie un raffinage poussé des fibres de cellulose qu'elle contient.For the purposes of the present invention, the term "tracing paper" is used traditionally in the paper industry to refer to a so-called "natural" tracing paper obtained from an aqueous suspension of paper pulp which has undergone extensive refining of cellulose fibers which 'it contains.

En effet les pâtes papetières doivent subir une étape de raffinage afin d'hydrater et de fibriller les fibres. Cette étape densifie le matelas fibreux se formant sur la toile de la machine à papier et permet de maîtriser les caractéristiques physiques et optiques de la feuille de papier. Lors de la fabrication de papier calque, cette étape de raffinage est poussée de manière à obtenir une feuille très dense presque exempte d'air (de vides), ce qui donne la transparence au papier.In fact, paper pulps must undergo a refining step in order to hydrate and fibrillate the fibers. This step densifies the fibrous mat forming on the web of the paper machine and controls the physical and optical characteristics of the paper sheet. During the manufacture of tracing paper, this refining step is pushed to obtain a very dense sheet almost free of air (voids), which gives transparency to the paper.

Dans la fabrication de papier calque, on procède donc à un raffinage mécanique d'une pâte en suspension aqueuse avant sa mise en oeuvre sur la machine à papier. Cette étape de fibrillation est réalisée dans des raffineurs mécaniques qui sont des dispositifs gros consommateurs d'énergie.In the manufacture of tracing paper, mechanical refining of a paste in aqueous suspension is then carried out before it is used on the paper machine. This fibrillation step is carried out in mechanical refiners which are large energy consuming devices.

Par ailleurs le haut degré de raffinage des fibres entraîne des problèmes de machinabilité, en particulier des problèmes d'égouttabilité de la pâte lors de la formation de la feuille sur la machine à papier. Or on sait que l'égouttage de la pâte papetière sur la toile d'une machine à papier joue un rôle particulièrement important dans la productivité, notamment pour le papier calque. En effet, il est nécessaire de chauffer la pâte raffinée à des températures de 80 à 95 °C par exemple pour faciliter l'égouttage et ainsi augmenter la productivité de la machine à papier. Ceci entraîne aussi une certaine consommation d'énergie.Moreover, the high degree of refining of the fibers causes machinability problems, in particular problems of drainability of the dough during the formation of the sheet on the paper machine. However, it is known that the dewatering of paper pulp on the web of a paper machine plays a particularly important role in productivity, especially for tracing paper. Indeed, it is necessary to heat the refined pulp at temperatures of 80 to 95 ° C for example to facilitate drainage and thus increase the productivity of the paper machine. This also leads to some energy consumption.

De plus, malgré ce chauffage de la pâte, le temps d'égouttage peut être assez long par rapport au temps d'égouttage d'une pâte peu raffinée (pour faire un papier classique non transparent).In addition, despite this heating of the dough, the dewatering time can be quite long compared to the dewatering time of a poorly refined dough (to make a conventional non-transparent paper).

La demande de brevet français FR 2 557 894 décrit un procédé de traitement de pâtes papetières par une solution enzymatique particulière à base de xylanases favorisant la fibrillation. Selon ce procédé de traitement, une solution de xylanases est ajoutée à une suspension fibreuse de pâtes papetières. La pâte ainsi traitée est ensuite raffinée mécaniquement. Ce traitement enzymatique de la pâte engendre un relâchement de la structure des fibres, relâchement qui favorise l'action ultérieure de l'étape de raffinage.The French patent application FR 2,557,894 discloses a method of treating paper pulps with a particular enzymatic solution based on xylanases promoting fibrillation. According to this treatment method, a solution of xylanases is added to a fibrous suspension of paper pulp. The dough thus treated is then refined mechanically. This enzymatic treatment of the pulp causes a loosening of the fiber structure, loosening which favors the subsequent action of the refining step.

La demande de brevet européen EP 0 262 040 décrit un procédé de traitement d'une pâte papetière à base de fibres recyclées par une préparation enzymatique contenant des cellulases et/ou hémicellulases. Le but poursuivi dans ce document est l'amélioration de l'égouttage de la suspension aqueuse de matière fibreuse sans qu'il y ait d'effet indésirable sur les caractéristiques mécaniques du papier fabriqué à partir de cette pâte. La technique employée pour améliorer l'égouttage de la suspension aqueuse de fibres amenée sur la toile d'une machine à papier ne fait pas appel à une pâte papetière à base de fibres vierges ayant des taux de fibrillation et de fines faibles. De plus, ce document ne décrit pas la fabrication d'un papier calque.The European patent application EP 0 262 040 discloses a process for treating a paper pulp made from recycled fibers with an enzyme preparation containing cellulases and / or hemicellulases. The purpose of this document is to improve the drainage of the aqueous suspension of fibrous material without any undesirable effect on the mechanical characteristics of the paper made from this paste. The technique used to improve the dewatering of the aqueous fiber suspension fed to the web of a paper machine does not make use of a virgin fiber paper pulp having low fibrillation and fine rates. In addition, this document does not describe the manufacture of a tracing paper.

La publication de brevet japonais JP 06 316899 décrit un papier cristal fabriqué en utilisant une pâte à papier préalablement soumise à une hydrolyse enzymatique. Cette technique vise à rendre la pâte plus facilement malaxable ce qui contribue à réduire la consommation d'énergie très importante lors du malaxage de la pâte et également à fournir un papier cristal ayant une transparence améliorée. Toutefois, ce document ne concerne pas la fabrication d'un papier calque.Japanese patent publication JP 06 316899 discloses a crystal paper made using a paper pulp previously subjected to enzymatic hydrolysis. This technique is intended to make the dough easier to knead, which contributes to reducing the very high energy consumption during kneading of the dough and also to providing a crystal paper having an improved transparency. However, this document does not concern the manufacture of a tracing paper.

La présente invention vise à résoudre les inconvénients de l'art antérieur de la fabrication d'un papier calque, notamment de diminuer les coûts énergétiques de cette fabrication tout en maintenant de bonnes caractéristiques mécaniques et optiques du papier calque.The present invention aims to solve the disadvantages of the prior art of the manufacture of a tracing paper, in particular to reduce the energy costs of this manufacture while maintaining good mechanical and optical characteristics of the tracing paper.

L'invention fournit ainsi un procédé de fabrication d'une feuille de papier calque présentant de bonnes caractéristiques mécaniques et un faible indice d'opacité, dont la pâte papetière à base de fibres cellulosiques vierges en suspension aqueuse est soumise à l'action d'une préparation enzymatique à base de cellulases avant son raffinage mécanique.The invention thus provides a method for manufacturing a sheet of tracing paper having good mechanical characteristics and a low opacity index, the pulp of which is based on virgin cellulosic fibers in aqueous suspension is subjected to the action of an enzyme preparation based on cellulases prior to mechanical refining.

La Demanderesse a constaté de manière surprenante que le procédé selon l'invention permet d'une part d'améliorer l'égouttage de la pâte en suspension grâce à l'accélération de l'égouttage, et/ou de diminuer la température de la suspension de la pâte en caisse de tête qui va être égouttée, et d'autre part d'avoir un gain d'énergie lors de la production de papier calque, notamment en diminuant la quantité d'énergie de raffinage nécessaire.The Applicant has found, surprisingly, that the process according to the invention makes it possible, on the one hand, to improve the dewatering of the suspension paste by accelerating the dewatering, and / or to reduce the temperature of the suspension pulp in headbox that will be drained, and secondly to have a gain in energy during the production of tracing paper, in particular by reducing the amount of refining energy required.

L'homme du métier dans le domaine de la papeterie sait que l'étape de raffinage des fibres cellulosiques nécessite d'être particulièrement poussée dès lors que l'on veut fabriquer du papier calque. Par ailleurs, l'homme du métier sait que les fibrilles et fines ainsi crées ralentissent la vitesse d'égouttage de la pâte.Those skilled in the field of stationery know that the refining step of cellulosic fibers needs to be particularly pushed when one wants to make tracing paper. Moreover, those skilled in the art know that the fibrils and fines thus created slow down the dripping speed of the dough.

De ce fait, l'homme du métier pensait que l'amélioration du procédé de raffinage par une action enzymatique ne permettrait pas d'augmenter la vitesse d'égouttage de la pâte en suspension. Or, la Demanderesse, contrairement aux préjugés de l'homme du métier, a pu après de nombreux travaux de recherche mettre au point un procédé de fabrication de papier calque, à savoir un papier comprenant des fibres cellulosiques très raffinées et présentant de bonnes caractéristiques mécaniques et un faible indice d'opacité, qui permet à la fois d'améliorer l'égouttage de la pâte et de réduire la consommation d'énergie, en particulier de l'énergie de raffinage et de l'énergie liée à la diminution de quelques degrés Celsius de la température de la suspension de pâte destinée à l'égouttage.As a result, one skilled in the art thought that improving the refining process by an enzymatic action would not make it possible to increase the dripping speed of the suspended pulp. However, the Applicant, contrary to the prejudices of the skilled person, was able after much research to develop a tracing paper manufacturing process, namely a paper comprising cellulosic fibers very refined and having good mechanical characteristics and a low opacity index, which allows both to improve the drip of the dough and to reduce the energy consumption, in particular of the energy of refining and the energy related to the decrease of some degrees Celsius of the temperature of the dough suspension for dripping.

Le procédé de fabrication d'une feuille de papier calque ayant un indice d'opacité inférieur à 40%, mesure faite selon la norme ISO 2469, selon l'invention est caractérisé par le fait qu'il comporte les étapes suivantes :

  1. a) on fait agir sur une suspension aqueuse de pâte papetière dont la composition fibreuse comprend au moins 50% en poids sec de fibres cellulosiques vierges, une préparation enzymatique contenant des cellulases ;
  2. b) après un temps d'action enzymatique sur ladite pâte d'au plus 60 minutes (à l'étape a)), on inhibe l'action enzymatique des cellulases sur ladite pâte papetière,
  3. c) on effectue un raffinage mécanique de la pâte papetière obtenue à l'étape b),
  4. d) on égoutte ladite pâte papetière raffinée sur la toile de la machine à papier,
  5. e) on sèche la feuille ainsi formée de sorte à obtenir ladite feuille de papier calque.
The method of manufacturing a sheet of tracing paper having an opacity index of less than 40%, measured according to the ISO 2469 standard, according to the invention is characterized in that it comprises the following steps:
  1. a) is made to act on an aqueous suspension of paper pulp whose fibrous composition comprises at least 50% by dry weight of virgin cellulosic fibers, an enzymatic preparation containing cellulases;
  2. b) after an enzymatic action time on said dough of not more than 60 minutes (in step a)), the enzymatic action of the cellulases on said paper pulp is inhibited,
  3. c) a mechanical refining of the pulp obtained in step b) is carried out,
  4. d) said fine paper pulp is drained onto the fabric of the paper machine,
  5. e) the sheet thus formed is dried so as to obtain said sheet of tracing paper.

Selon un cas particulier de l'invention, on fabrique un papier calque pouvant avoir un indice d'opacité inférieur à 30 %, mesure faite selon la norme ISO 2469.According to a particular case of the invention, a tracing paper is manufactured which can have an opacity index of less than 30%, measured according to the ISO 2469 standard.

Le procédé selon l'invention s'applique à des pâtes papetières à base de fibres cellulosiques vierges. Ainsi, la composition fibreuse de la pâte papetière selon l'invention peut comprendre au moins 50% de fibres cellulosiques vierges en poids sec, préférentiellement au moins 70% de fibres cellulosiques vierges en poids sec, par rapport au poids sec total de la composition fibreuse de la pâte papetière. Plus préférentiellement encore la composition peut comprendre 100 % de fibres vierges.The process according to the invention applies to paper pulp based on virgin cellulosic fibers. Thus, the fibrous composition of the paper pulp according to the invention may comprise at least 50% of virgin cellulosic fibers in dry weight, preferably at least 70% of virgin cellulosic fibers in dry weight, relative to to the total dry weight of the fibrous composition of the pulp. More preferably still the composition may comprise 100% virgin fibers.

On entend par " fibres vierges " au sens de la présente invention, comme usuellement dans l'industrie papetière, des fibres non recyclées, ces fibres pouvant en autre provenir des cassés de fabrication.The term "virgin fibers" in the sense of the present invention, as usually used in the paper industry, non-recycled fibers, these fibers may in addition come from broken manufacturing.

Les cassés de fabrication correspondent au papier éliminé à un stade quelconque de la fabrication sur la machine à papier et généralement remis en pâte. On distingue d'une part les cassés de fabrication humides, c'est-à-dire accumulés dans la partie humide de la machine à papier et d'autre part les cassés de fabrication secs, accumulés en un point quelconque de la sècherie de la machine à papier, les rognures provenant des opérations de bobinage, de re-fente et de coupe ainsi que le papier rejeté au triage.Broken manufacturing is paper removed at any stage of manufacture on the paper machine and generally pulped. One distinguishes on the one hand the wet manufacturing breaks, that is to say accumulated in the wet part of the paper machine and on the other hand the dry manufacturing breaks, accumulated at any point of the dryness of the machine. paper machine, trimmings from winding, re-slitting and cutting operations as well as paper rejected in sorting.

Typiquement, les pâtes papetières utilisées pour la fabrication de papier calque sont choisies parmi les pâtes kraft blanchie de résineux du Nord, les pâtes Kraft blanchies de résineux du Sud et leur mélange. Ces pâtes papetières peuvent être éventuellement associées à de faibles quantités de pâte de type feuillu. Les pâtes blanchies au bisulfite peuvent également être utilisées pour la fabrication de papier calque.Typically, papermaking pulps used for the manufacture of tracing paper are selected from bleached northern softwood kraft pulp, bleached softwood kraft pulp from the South and blend thereof. These papermaking pulps may possibly be associated with small quantities of hardwood type pulp. Bleached sulphite pulps can also be used for the manufacture of tracing paper.

L'action enzymatique à l'étape a) se fait sur la pâte aux conditions requises de pH et de température pour que les enzymes soient actives, conformément aux connaissances dans le domaine des biotechnologies.The enzymatic action in step a) is performed on the pulp at the required pH and temperature conditions for the enzymes to be active, according to the knowledge in the field of biotechnology.

De préférence, la préparation enzymatique de l'invention utilise des cellulases de type endo-1,4-β-glucanase, qui sont couramment appelées « endoglucanases ».Preferably, the enzymatic preparation of the invention uses endo-1,4-β-glucanase-type cellulases, which are commonly referred to as "endoglucanases".

Dans un mode de réalisation particulier de l'étape a) du procédé l'invention, on ajoute, dans le pulpeur, à la pâte papetière constituée d'au moins 50% de fibres cellulosiques vierges en suspension aqueuse à raison de 50g/l, la préparation enzymatique contenant les cellulases.In a particular embodiment of step a) of the process of the invention, the pulp is added to the paper pulp composed of at least 50% of virgin cellulosic fibers in aqueous suspension at a rate of 50 g / l, the enzyme preparation containing the cellulases.

Selon un cas particulier de l'invention, on ajoute à ladite suspension aqueuse à base de fibres cellulosiques vierges de 0,05 à 1 gramme d'une cellulase, en particulier de type endoglucanase, par kilogramme de pâte papetière en poids sec, et l'on mélange le tout pendant un temps n'excédant pas 60 minutes.According to a particular case of the invention, 0.05 to 1 gram of a cellulase, in particular of endoglucanase type, is added to said aqueous suspension based on virgin cellulosic fibers per kilogram of paper pulp on a dry weight basis, and the whole is mixed for a time not exceeding 60 minutes.

En effet, la Demanderesse a constaté que le traitement enzymatique de la pâte papetière en suspension de l'étape a) du procédé ne nécessite pas d'être poursuivi au delà de 60 minutes. On arrête par conséquent la réaction enzymatique des cellulases, de préférence en l'inhibant par ajout d'un inhibiteur chimique à la suspension de pâte. Selon l'étape b) du procédé de l'invention, on inhibe l'action enzymatique des cellulases en ajoutant à ladite suspension aqueuse de pâte un inhibiteur chimique de sorte que le temps de traitement enzymatique de ladite suspension aqueuse de pâte n'excède pas 60 minutes.Indeed, the Applicant has found that the enzymatic treatment of the pulp in suspension of step a) of the process does not require to be continued beyond 60 minutes. The enzymatic reaction of the cellulases is therefore stopped, preferably by inhibiting it by addition of a chemical inhibitor to the pulp suspension. According to step b) of the process of the invention, the enzymatic action of the cellulases is inhibited by adding to said aqueous suspension of paste a chemical inhibitor so that the enzymatic treatment time of said aqueous suspension of dough does not exceed 60 minutes.

Selon un mode avantageux de l'invention, ledit inhibiteur chimique est un oxydant fort. Plus particulièrement, ledit inhibiteur chimique est choisi parmi l'hypochlorite de sodium et le peroxyde d'hydrogène, notamment utilisé sous forme d'une solution aqueuse.According to an advantageous embodiment of the invention, said chemical inhibitor is a strong oxidizer. More particularly, said chemical inhibitor is chosen from sodium hypochlorite and hydrogen peroxide, especially used in the form of an aqueous solution.

Selon l'invention, le temps d'action enzymatique des cellulases sur la suspension aqueuse de pâte est préférentiellement compris entre 5 et 45 minutes, plus préférentiellement entre 5 et 30 minutes.According to the invention, the enzymatic action time of the cellulases on the aqueous pulp suspension is preferably between 5 and 45 minutes, more preferably between 5 and 30 minutes.

Une méthode pour déterminer que l'inhibition des enzymes a bien eu lieu, est de suivre la viscosité de solutions de CMC (carboxyméthylcellulose) faites avec les eaux d'échantillons de pâte, prélevés avant et après l'ajout de l'inhibiteur, selon la méthode décrite plus loin après les exemples.One method to determine that enzyme inhibition has occurred is to track the viscosity of CMC (carboxymethylcellulose) solutions made with the water of dough samples taken before and after the addition of the inhibitor, according to the method described later after the examples.

La solution de CMC relative à l'échantillon prélevé avant l'ajout de l'inhibiteur (une fois amenée à la température d'activité des enzymes) perd rapidement sa viscosité du fait de l'action des enzymes sur les chaînes de cellulose alors que la solution de CMC relative à l'échantillon prélevé après l'ajout de l'inhibiteur (une fois amenée à la température d'activité des enzymes) reste stable en viscosité.The CMC solution for the sample taken before the addition of the inhibitor (once brought to the activity temperature of the enzymes) quickly loses its viscosity due to the action of the enzymes on the cellulose chains whereas the CMC solution relative to the sample taken after the addition of the inhibitor (once brought to the activity temperature of the enzymes) remains stable in viscosity.

Cette méthode permet d'optimiser les concentration et quantité de l'inhibiteur ainsi que le temps d'inhibition.This method makes it possible to optimize the concentration and quantity of the inhibitor as well as the inhibition time.

Une fois que l'action enzymatique de la préparation enzymatique à base de cellulases est inhibée, la pâte papetière ainsi traitée, issue de l'étape b) du procédé, est soumise selon l'étape c) du procédé de l'invention à un raffinage mécanique. De manière usuelle, le raffinage mécanique est réalisé au moyen de raffineur(s). Selon un aspect de l'invention, on raffine la pâte à papier à un degré Schöpper-Riegler supérieur à 80.Once the enzymatic action of the cellulase-based enzyme preparation is inhibited, the pulp thus treated, resulting from step b) of the process, is subjected according to step c) of the process of the invention to a mechanical refining. Usually, the mechanical refining is carried out by means of refiner (s). According to one aspect of the invention, the paper pulp is refined to a Schöpper-Riegler degree greater than 80.

Une réduction de la consommation de l'énergie de raffinage lors du raffinage mécanique de la pâte a pu être constatée suite à l'action enzymatique des cellulases sur la pâte en suspension aqueuse.A reduction in the consumption of the refining energy during the mechanical refining of the pulp could be observed following the enzymatic action of the cellulases on the pulp in aqueous suspension.

Selon l'étape d) du procédé de l'invention, on dépose la suspension aqueuse de pâte obtenue sur la toile d'une machine à papier, en général une machine à papier à table plate, et l'on égoutte l'eau par gravité et au moyen de foils et d'autres organes d'égouttage.According to step d) of the process of the invention, the aqueous pulp suspension obtained is deposited on the fabric of a paper machine, generally a flat-bed paper machine, and the water is drained by gravity and by means of foils and other dewatering devices.

L'étape d) du procédé de fabrication de papier calque selon l'invention se caractérise par une amélioration de la vitesse d'égouttage de la pâte sur la toile de la machine à papier par rapport à une même pâte non traitée par enzymes. La vitesse d'égouttage de la suspension aqueuse de pâte obtenue à l'issue de l'étape c) du procédé se caractérise par un temps d'égouttage déterminé selon le test décrit ci-après au paragraphe «DESCRIPTION ET CONDITIONS DE REALISATION DE LA MESURE DE L'EGOUTTAGE » pour un volume donné, compris entre 40 et 60 secondes.Step d) of the tracing paper manufacturing method according to the invention is characterized by an improvement in the drip rate of the dough on the fabric of the paper machine compared to the same dough not treated with enzymes. The dewatering speed of the aqueous pulp suspension obtained at the end of stage c) of the process is characterized by a dewatering time determined according to the test described below in the paragraph "DESCRIPTION AND CONDITIONS OF REALIZATION OF THE MEASURING DRAINAGE "for a given volume, between 40 and 60 seconds.

Une amélioration de la vitesse d'égouttage de la pâte sur la toile de la machine à papier lors de l'étape d) du procédé selon l'invention a été constatée pour un papier calque ayant un indice d'opacité donné et inférieur à 40%. En effet, la vitesse d'égouttage de ladite pâte traitée et raffinée, qui est caractérisée par un temps d'égouttage déterminé selon le test décrit ci-après au paragraphe « DESCRIPTION ET CONDITIONS DE REALISATION DE LA MESURE DE L'EGOUTTAGE » pour un volume donné, peut être améliorée d'au moins 10% par rapport à la vitesse d'égouttage d'une pâte non traitée préalablement par voie enzymatique, mais raffinée de sorte à permettre l'obtention d'un papier calque de valeur d'opacité identique, ladite vitesse d'égouttage étant caractérisée par un temps d'égouttage déterminé selon le même test décrit ci-après au paragraphe «DESCRIPTION ET CONDITIONS DE REALISATION DE LA MESURE DE L'EGOUTTAGE ».An improvement in the drip speed of the dough on the web of the paper machine during step d) of the method according to the invention was observed for a tracing paper having a given opacity index and less than 40 %. Indeed, the dewatering speed of said processed and refined pulp, which is characterized by a dewatering time determined according to the test described below in the paragraph "DESCRIPTION AND CONDITIONS OF REALIZATION OF THE SEGMENT MEASUREMENT" for a given volume, can be improved by at least 10% with respect to the dewatering speed of a paste that has not been previously treated enzymatically, but refined so as to obtain a tracing paper of opacity value identical, said dewatering speed being characterized by a dewatering time determined according to the same test described below in the paragraph "DESCRIPTION AND CONDITIONS OF REALIZATION OF THE MEASUREMENT OF DRAINAGE".

D'une façon générale, lors de la fabrication d'un papier calque, on règle la température de la suspension de la pâte entre environ 80 et 95°C pour permettre un meilleur égouttage de la feuille de papier. Or, les inventeurs ont constaté de façon surprenante, au cours de leur nombreuses expériences, que non seulement la vitesse d'égouttage de la pâte sur la toile de la machine à papier se trouvait nettement améliorée mais aussi que la température de la suspension de pâte pouvait être réduite de quelques degré Celsius, à savoir de 2 à 10°C pour l'égouttage. Ainsi, lors de la fabrication d'un papier calque selon le procédé de l'invention, on peut régler la température de la pâte en suspension à une température inférieure ou égale à 80°C, de préférence entre 70 et 75°C,et la vitesse d'égouttage sur la toile de la machine à papier de la pâte issue de l'étape d) reste nettement améliorée. Cette diminution de la température de la suspension de pâte au même titre que la réduction de l'énergie de raffinage de la pâte représente un gain d'énergie.In general, during the manufacture of a tracing paper, the temperature of the suspension of the dough is adjusted between about 80 and 95 ° C to allow better drainage of the paper sheet. However, the inventors have surprisingly found, during their many experiments, that not only the drip rate of the dough on the fabric of the paper machine was significantly improved but also that the temperature of the dough suspension could be reduced by a few degrees Celsius, ie from 2 to 10 ° C for dripping. Thus, during the manufacture of a tracing paper according to the process of the invention, the temperature of the dough in suspension can be adjusted to a temperature of less than or equal to 80 ° C., preferably between 70 and 75 ° C., and the dripping speed on the fabric of the paper machine of the dough resulting from step d) remains significantly improved. This decrease in the temperature of the pulp suspension as well as the reduction of the pulp refining energy represents an energy gain.

Plus particulièrement, selon l'invention, la pâte raffinée obtenue à l'issue de l'étape c) est chauffée à ladite température, dans le circuit court de la machine à papier l'amenant jusqu'à la caisse de tête de la machine à papier.More particularly, according to the invention, the refined paste obtained at the end of step c) is heated to said temperature, in the short circuit of the paper machine leading to the headbox of the machine paper.

Ensuite, lors de l'étape e) du procédé de l'invention on sèche la feuille de papier calque obtenue à l'étape d) du procédé sur des rouleaux sécheurs.Then, during step e) of the process of the invention, the sheet of tracing paper obtained in step d) of the process is dried on drying rollers.

La feuille de papier calque ainsi obtenue présente un indice d'opacité relativement faible propre aux feuilles de papier calque, plus précisément un indice d'opacité inférieur à 40 %, de préférence inférieur à 30 %, mesure faite selon la norme ISO 2469.The sheet of tracing paper thus obtained has a relatively low opacity index specific to the tracing paper sheets, more specifically an opacity index of less than 40%, preferably less than 30%, measured according to the ISO 2469 standard.

On obtient ainsi une feuille de papier calque selon le procédé de l'invention qui présente de bonnes caractéristiques mécaniques et un faible indice d'opacité, et qui possède un grammage compris entre environ 30 et 200 g/m2 voire jusqu'à 300 g/m2.This gives a sheet of tracing paper according to the method of the invention which has good mechanical characteristics and a low opacity index, and which has a basis weight of between about 30 and 200 g / m 2 or even up to 300 g / m 2 .

On peut éventuellement ajouter un colorant, par exemple dans la suspension aqueuse de la pâte avant la caisse de tête de la machine à papier, de sorte à obtenir une feuille de papier calque colorée.A dye may be added, for example, in the aqueous suspension of the dough before the head box of the paper machine, so as to obtain a colored sheet of tracing paper.

Les figures annexées et l'exemple non limitatif ainsi que l'exemple comparatif suivants permettront de mieux comprendre l'invention.The appended figures and the nonlimiting example and the comparative example below will make it possible to better understand the invention.

Exemple 1 selon l'inventionExample 1 according to the invention

On met en suspension dans de l'eau chaude à environ 70 °C, dans un pulpeur, 750 kg en poids sec (soit 80% par rapport au poids de la feuille) de fibres vierges longues d'une pâte Kraft blanchie de résineux et 180 kg en poids sec de cassés (soit 20 % par rapport au poids sec de la feuille), de sorte à obtenir une concentration de 50g/l.750 kg dry weight (ie 80% based on the weight of the sheet) of long virgin fibers of a bleached Kraft softwood pulp are suspended in hot water at approximately 70 ° C. in a pulper. 180 kg dry weight of broken (ie 20% relative to the dry weight of the sheet), so as to obtain a concentration of 50g / l.

On ajoute à ladite dispersion aqueuse à base de fibres 0,2 gramme d'enzymes cellulases de type endo-1,4-β-glucanase par kilogramme du mélange pâte en poids sec. On maintient l'activité enzymatique pendant 15 minutes, puis on l'arrête en ajoutant à ladite suspension aqueuse de pâte une solution aqueuse d'hypochlorite de sodium.0.2 gram of endo-1,4-β-glucanase cellulase enzymes per kilogram of the dough mixture on a dry weight basis is added to said aqueous fiber dispersion. The enzymatic activity is maintained for 15 minutes and then stopped by adding an aqueous solution of sodium hypochlorite to said aqueous slurry.

La suspension de fibres est à une température d'environ 50 °C et son pH a été ajusté entre 6 et 8 pour être dans les conditions d'activation des enzymes.The fiber suspension is at a temperature of about 50 ° C and its pH was adjusted to between 6 and 8 to be in the enzyme activation conditions.

On raffine la suspension de pâte à papier dans un raffineur mécanique en appliquant une énergie de raffinage de 500 kWh/tonne de sorte à obtenir un niveau de fibrillation conduisant à une opacité finale de la feuille de papier de 36%.The pulp suspension is refined in a mechanical refiner by applying a refining energy of 500 kWh / ton so as to obtain a level of fibrillation leading to a final opacity of the paper sheet of 36%.

On chauffe la pâte ainsi raffinée dans le circuit court de la machine à papier à une température d'environ 80°C, et on l'amène jusqu'à la caisse de tête puis on dépose la pâte sur la toile d'une machine à papier à table plate, on l'égoutte et on la presse.The dough thus refined is heated in the short circuit of the paper machine at a temperature of about 80 ° C., and it is brought to the headbox and then the dough is deposited on the fabric of a machine. flat-table paper, it is drained and pressed.

Puis, on sèche la feuille de papier calque ainsi obtenue sur des rouleaux sécheurs à environ 100 °C.Then, the sheet of tracing paper thus obtained is dried on drying rollers at about 100 ° C.

On obtient ainsi une feuille de papier calque ayant un indice d'opacité de 36 % et un grammage de 110 g/m2.This gives a sheet of tracing paper having an opacity index of 36% and a basis weight of 110 g / m 2 .

Exemple 2 comparatif selon l'art antérieurComparative Example 2 According to the Prior Art

On met en suspension dans de l'eau, dans un pulpeur, 750 kg en poids sec (soit 80% par rapport au poids de la feuille) de fibres vierges longues d'une pâte Kraft blanchie de résineux et 180 kg en poids sec de cassés (soit 20 % par rapport au poids sec de la feuille), de sorte à obtenir une concentration de 50g/l.750 kg dry weight (ie 80% relative to the weight of the sheet) of long virgin fibers of a bleached Kraft softwood pulp and 180 kg of dry weight are suspended in water in a pulper. broken down (ie 20% relative to the dry weight of the sheet), so as to obtain a concentration of 50 g / l.

On raffine cette suspension de pâte à papier dans un raffineur mécanique en appliquant une énergie de raffinage de 800 kWh/tonne de sorte à obtenir un niveau de fibrillation conduisant à une opacité finale de la feuille de papier de 36%.This pulp suspension is refined in a mechanical refiner by applying a refining energy of 800 kWh / ton so as to obtain a level of fibrillation leading to a final opacity of the paper sheet of 36%.

On chauffe la pâte ainsi raffinée dans le circuit court de la machine à papier à une température d'environ 85°C, et on l'amène jusqu'à la caisse de tête puis on dépose la pâte sur la toile d'une machine à papier à table plate, on l'égoutte et on la presse. Puis, on sèche la feuille de papier calque ainsi obtenue sur des rouleaux sécheurs à environ 100 °C.The dough thus refined is heated in the short circuit of the paper machine at a temperature of about 85 ° C., and it is brought to the headbox and then deposited on the fabric of a machine. flat-table paper, it is drained and pressed. Then, the sheet of tracing paper thus obtained is dried on drying rollers at about 100 ° C.

On obtient ainsi une feuille de papier calque ayant un indice d'opacité de 36 % et un grammage de 110 g/m2.This gives a sheet of tracing paper having an opacity index of 36% and a basis weight of 110 g / m 2 .

Figures :Figures:

  • La figure 1 représente la courbe de l'indice d'opacité en fonction de l'énergie de raffinage d'une feuille de papier calque issue d'une pâte traitée par action enzymatique selon l'invention (exemple 1) et celle d'une feuille de papier calque issue d'une pâte non traitée selon l'art antérieur (exemple 2).The figure 1 represents the curve of the opacity index as a function of the refining energy of a sheet of tracing paper obtained from an enzyme-treated paste according to the invention (example 1) and that of a sheet of paper layer resulting from an untreated pulp according to the prior art (example 2).
  • La figure 2 représente la courbe du temps d'égouttage (noté Dv) en fonction de l'énergie de raffinage d'une feuille de papier calque issue d'une pâte traitée par action enzymatique selon l'invention (exemple 1) et celle d'une feuille de papier calque issue d'une pâte non traitée par enzyme selon l'art antérieur (exemple 2).The figure 2 represents the curve of the dewatering time (denoted Dv) as a function of the refining energy of a sheet of tracing paper resulting from an enzyme-treated paste according to the invention (example 1) and that of a sheet of tracing paper from a paste not treated with enzyme according to the prior art (Example 2).
Interprétation des résultatsResults interpretation

La figure 1 représente l'influence du traitement enzymatique sur l'énergie de raffinage de la pâte en suspension aqueuse.The figure 1 represents the influence of enzymatic treatment on the refining energy of the pulp in aqueous suspension.

Comme on peut le voir sur le figure 1, l'indice d'opacité de 36 % d'une feuille de papier calque obtenue selon le même procédé que celui de l'invention mais dont la pâte en suspension aqueuse est exempte de tout traitement enzymatique (exemple 2), nécessite une énergie de raffinage de 800 kWh/tonne tandis que le même indice d'opacité de 36 % peut être obtenu pour une feuille de papier calque telle que décrite dans l'exemple 1 dont la pâte en suspension aqueuse a été soumise à un traitement enzymatique à raison de 0,2 gramme d'une cellulase de type endo-1,4-β-glucanase par kilogramme de pâte avec une énergie de raffinage de l'ordre de 500 kWh/tonne. Par conséquent, un papier calque obtenu selon le procédé de l'invention permet une diminution de la consommation d'énergie de raffinage d'environ 38%.As can be seen on the figure 1 , the opacity index of 36% of a sheet of tracing paper obtained according to the same process as that of the invention but whose paste in aqueous suspension is free of any enzymatic treatment (Example 2), requires an energy of refining of 800 kWh / ton while the same opacity index of 36% can be obtained for a sheet of tracing paper as described in Example 1, the pulp in aqueous suspension was subjected to enzymatic treatment at the rate of 0.2 gram of an endo-1,4-β-glucanase cellulase per kilogram of pulp with a refining energy of the order of 500 kWh / ton. Therefore, a tracing paper obtained according to the method of the invention allows a reduction in the energy consumption of refining of about 38%.

La figure 2 représente l'influence du traitement enzymatique sur le temps d'égouttage (Dv). Le procédé de fabrication de papier calque selon l'invention permet comme précédemment décrit une amélioration de la vitesse d'égouttage de la pâte sur la toile de la machine à papier, vitesse d'égouttage de la dite pâte qui se caractérise par un temps d'égouttage déterminé selon le test décrit ci-après au paragraphe « DESCRIPTION ET CONDITIONS DE REALISATION DE LA MESURE DE L'EGOUTTAGE » pour un volume donné.The figure 2 represents the influence of enzymatic treatment on the dewatering time (Dv). The tracing paper manufacturing method according to the invention, as previously described, makes it possible to improve the dripping speed of the dough on the fabric of the paper machine, the dripping speed of the dough which is characterized by a time of dyeing. draining determined according to the test described below in the paragraph "DESCRIPTION AND CONDITIONS FOR PERFORMING THE MEASUREMENT OF DRAINAGE" for a given volume.

Comme on peut le voir sur la courbe représentant le temps d'égouttage en fonction de l'énergie de raffinage de la figure 2, le temps d'égouttage (en secondes) déterminé selon le test décrit ci-après, d'une feuille de papier calque telle que décrite dans l'exemple 1 selon l'invention dont la pâte en suspension aqueuse a été soumise à un traitement enzymatique à raison de 0,2 gramme d'une cellulase de type endo-1,4-β-glucanase par kilogramme de pâte pour une énergie de raffinage (en kWh/tonne) de 500 kWh/tonne, est de 48 s. Or, on constate que le temps d'égouttage (en secondes) déterminé selon le même test décrit ci-après, d'une feuille de papier calque obtenue selon le même procédé que celui de l'invention mais dont la pâte en suspension aqueuse est exempte de tout traitement enzymatique selon l'exemple 2 pour une énergie de raffinage de 800 kWh/tonne, est de 95 s.As can be seen on the curve representing the dewatering time as a function of the refining energy of the figure 2 , the dewatering time (in seconds) determined according to the test described below, of a sheet of tracing paper as described in Example 1 according to the invention, the paste in aqueous suspension was subjected to a treatment 0.2 gram of an endo-1,4-β-glucanase cellulase per kilogram of pulp for a refining energy (in kWh / ton) of 500 kWh / ton, is 48 s. However, it is found that the dewatering time (in seconds) determined according to the same test described below, a sheet of tracing paper obtained according to the same process as that of the invention but whose pulp in aqueous suspension is free of any enzymatic treatment according to Example 2 for a refining energy of 800 kWh / ton, is 95 s.

Par conséquent un papier calque obtenu selon le procédé de l'invention permet une nette amélioration de la vitesse d'égouttage de la pâte sur la toile de la machine à papier, d'environ 50 %, en plus du gain d'énergie de raffinage d'environ 38%, pour une opacité équivalente de 36%.Therefore a tracing paper obtained according to the method of the invention allows a marked improvement in the dripping speed of the dough on the fabric of the paper machine, by about 50%, in addition to the gain in refining energy. about 38%, for an opacity equivalent of 36%.

DESCRIPTION ET CONDITIONS DE REALISATION DE LA MESURE DE L'EGOUTTAGE :DESCRIPTION AND CONDITIONS OF REALIZATION OF THE SELECTION MEASUREMENT:

La mesure de la vitesse d'égouttage de la pâte est caractérisée par la détermination du temps d'écoulement de l'eau par gravitation en secondes pour un volume donné, ce temps d'égouttage de la pâte est déterminé de la façon suivante :

  • on prélève un échantillon de pâte en suspension aqueuse et on détermine sa concentration en g/l, puis
  • on prépare, à partir de cet échantillon, un litre de suspension aqueuse de pâte de concentration égale à 0,5g/l, et sa température est de 15 °C
  • on ferme l'appareil de Schöpper-Riegler, normalisé selon la norme internationale IS05267-1 : 1999 et on met les (deux) sorties d'égouttage de l'appareil dans un récipient normalisé selon la même norme,
  • on introduit alors le litre de la préparation de suspension aqueuse de pâte à 0,5g/l dans le bol de l'appareil Schöpper-Riegler,
  • on ouvre les sorties d'égouttage de l'appareil et on déclenche simultanément un chronomètre,
  • on arrête le chronomètre dès que le volume d'eau égoutté dans le récipient normalisé atteint 610ml,
  • on note le temps d'égouttage, exprimé en secondes, nécessaire pour atteindre le volume de 610ml d'eau égoutté.
The measurement of the drip rate of the dough is characterized by the determination of the water flow time by gravitation in seconds for a given volume, this dewatering time of the dough is determined as follows:
  • a sample of paste is taken in aqueous suspension and its concentration is determined in g / l, then
  • from this sample, one liter of aqueous suspension of pulp concentration equal to 0.5 g / l, and its temperature is 15 ° C
  • the Schöpper-Riegler apparatus, standardized according to the international standard IS05267-1: 1999, is closed and the (two) drip outlets of the apparatus are placed in a standard container according to the same standard,
  • the liter of the aqueous paste suspension preparation at 0.5 g / l is then introduced into the bowl of the Schöpper-Riegler apparatus,
  • the drip outlets of the apparatus are opened and a chronometer is simultaneously triggered,
  • stop the stopwatch as soon as the volume of water drained in the standardized container reaches 610ml,
  • we note the draining time, expressed in seconds, necessary to reach the volume of 610ml of drained water.

La concentration en g/l de la pâte est déterminée classiquement par filtration d'un volume donné de l'échantillon de la suspension de pâte, on sèche la pâte récupérée et on la pèse.The concentration in g / l of the dough is conventionally determined by filtration of a given volume of the sample of the dough suspension, the recovered dough is dried and weighed.

DESCRIPTION DE LA DETERMINATION DE L'INHIBITION DES ENZYMES :DESCRIPTION OF THE DETERMINATION OF INHIBITION OF ENZYMES:

Deux échantillons de pâte, A et B, sont prélevés au pulpeur. L'échantillon A contient les enzymes avant inhibition et l'échantillon B (pris au même endroit 5 minutes plus tard) contient les enzymes et l'inhibiteur.Two dough samples, A and B, are taken from the pulper. Sample A contains the enzymes before inhibition and Sample B (taken at the same place 5 minutes later) contains the enzymes and the inhibitor.

Les deux échantillons de pâte sont essorés pour récupérer leurs eaux respectives qui sont ensuite réfrigérées pour désactiver toute enzyme non inhibée dans les deux lots.Both dough samples are dewatered to recover their respective waters which are then chilled to deactivate any uninhibited enzyme in both batches.

Une fois froides, à 4[deg.]C, ces eaux sont utilisées pour dissoudre de la CMC (carboxyméthylcellulose) pour avoir deux solutions respectives A et B de CMC.Once cold, at 4 [deg.] C, these waters are used to dissolve CMC (carboxymethylcellulose) to have two respective solutions A and B of CMC.

Les solutions de CMC sont ensuite portées à la température d'activité des enzymes (autour de 50°C) et les viscosités sont mesurées régulièrement.The CMC solutions are then brought to the enzyme activity temperature (around 50 ° C) and the viscosities are measured regularly.

La solution A de CMC, sans inhibiteur (une fois amenée à la température d'activité des enzymes), perd rapidement sa viscosité par l'action des enzymes sur les chaînes de cellulose alors que la solution B de CMC, avec inhibiteur, reste stable en viscosité. Nous pouvons donc conclure que l'inhibition a bien eu lieu.CMC solution A, without inhibitor (once brought to the enzyme activity temperature), rapidly loses its viscosity by the action of enzymes on the cellulose chains whereas CMC solution B, with inhibitor, remains stable in viscosity. We can therefore conclude that the inhibition has taken place.

Claims (13)

  1. A method for manufacturing a sheet of natural tracing paper having an opacity index of less than 40%, measured according to ISO 2469 standard, characterized in that it comprises the following successive steps:
    a. an enzyme preparation containing cellulases is reacted with an aqueous suspension of paper pulp, the fibrous composition of which comprises at least 50% by dry weight of virgin cellulosic fibers,
    b. after an enzymatic action time on said pulp of at most 60 minutes, the enzymatic action of cellulases on said paper pulp is inhibited using a chemical inhibitor,
    c. the paper pulp obtained in step b) is mechanically refined to a Schopper-Riegler degree above 80,
    d. said refined pulp is drained on the wire cloth of a paper machine,
    e. the sheet thus formed is dried so as to obtain said sheet of tracing paper.
  2. A method according to claim 1, characterized in that the paper pulp comprises at least 70% by dry weight of virgin cellulose fibers, relative to the total dry weight of the fiber composition of the paper pulp.
  3. A method according to claim 1, characterized in that said paper pulp consists of 100% by dry weight of virgin cellulose fibers, relative to the total dry weight of the fiber composition of the paper pulp.
  4. A method according to any one of claims 1 to 3, characterized in that the cellulases of the enzyme preparation of step a) are of the endo-1,4-β-glucanase type.
  5. A method according to any one of claims 1 to 4, characterized in that, during step a) 0.05 to 1 gram of cellulases per kg of paper pulp by dry weight is reacted.
  6. A method according to claim 5, characterized in that said chemical inhibitor is a strong oxidant.
  7. A method according to claim 6, characterized in that said chemical inhibitor is selected from sodium hypochlorite and hydrogen peroxide, especially in the form of an aqueous solution.
  8. A method according to any one of claims 1 to 7, characterized in that the enzyme action time of cellulases on the aqueous pulp suspension ranges from 5 to 45 minutes, more preferably from 5 to 30 minutes.
  9. A method according to any one of claims 1 to 8, characterized in that the refined pulp obtained at the end of step c) is heated up to a temperature of less than or equal to 80°C, prior to the step d) of drainage.
  10. A method according to preceding claim 9, characterized in that said temperature ranges from 70°C to 75°C.
  11. A method according to one of claims 9 to 10, characterized in that the refined pulp obtained at the end of step c) is heated to said temperature, in the short circuit of the paper machine leading same up to the headbox of the paper machine.
  12. A method according to any one of claims 1 to 11, characterized in that the aqueous pulp suspension is drained on the wire cloth of a Fourdrinier paper machine during step d) of said method.
  13. A method for manufacturing a sheet of tracing paper according to any one of claims 1 to 12, characterized in that the rate of drainage of the aqueous pulp suspension in step d) corresponds to a drainage time ranging from 40 to 60 seconds, with said drainage time being determined as follows:
    - a sample of the aqueous pulp suspension is taken and the concentration thereof is determined in g/l then
    - one liter of an aqueous pulp suspension having a concentration of 0.5g/l is prepared from this sample,
    - the Schopper-Riegler apparatus standardized according to ISO5267-1 : 1999 international standard is closed and the drainage outlets of the apparatus are placed in the same vessel standardized according to the same standard,
    - the liter of the preparation of an aqueous pulp suspension at 0.5g/l is then introduced into the bowl of the Schopper-Riegler apparatus,
    - the drainage outlets of the Schopper-Riegler apparatus are then opened and a chronometer is triggered simultaneously,
    - the chronometer is stopped as soon as the volume of water drained in the standardized vessel reaches 610 ml,
    - the drainage time, in seconds, required to reach the volume of 610ml of water drained is then noted.
EP07871997.8A 2006-12-22 2007-12-20 Tracing paper production method Active EP2122053B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0611303A FR2910500B1 (en) 2006-12-22 2006-12-22 PROCESS FOR PRODUCING PLATE PAPER
PCT/FR2007/052586 WO2008087337A2 (en) 2006-12-22 2007-12-20 Tracing paper production method

Publications (2)

Publication Number Publication Date
EP2122053A2 EP2122053A2 (en) 2009-11-25
EP2122053B1 true EP2122053B1 (en) 2019-01-09

Family

ID=38529473

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Application Number Title Priority Date Filing Date
EP07871997.8A Active EP2122053B1 (en) 2006-12-22 2007-12-20 Tracing paper production method

Country Status (4)

Country Link
EP (1) EP2122053B1 (en)
ES (1) ES2719628T3 (en)
FR (1) FR2910500B1 (en)
WO (1) WO2008087337A2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4310249A1 (en) 2022-07-19 2024-01-24 SAPPI Netherlands Services B.V. Translucent paper products

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2402504A1 (en) * 2010-06-29 2012-01-04 M-real Oyj Transparent paper containing fibrous materials from annual plants and/or other quick-growing non-wooden fibrous materials
FR2965570B1 (en) 2010-09-30 2012-11-02 Arjo Wiggins Fine Papers Ltd METHOD FOR THE ENZYMATIC REFINING OF A PAPER PULP COMPRISING CELLULOSIC FIBERS TO REDUCE THEIR LENGTH
EP3483337B1 (en) * 2017-11-14 2021-12-08 Aw Branding Limited Recyclable and repulpable translucent or transparent paper - use for packaging applications

Family Cites Families (8)

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Publication number Priority date Publication date Assignee Title
US2792765A (en) * 1954-03-12 1957-05-21 Riegel Paper Corp Manufacture of glassine and greaseproof papers
FI900544A (en) * 1990-02-02 1991-08-03 Enso Gutzeit Oy Tutkimuskeskus FOERFARANDE FOER TILLVERKNING AV MASSA.
DK115890D0 (en) * 1990-05-09 1990-05-09 Novo Nordisk As ENZYME
JPH06316899A (en) * 1993-04-30 1994-11-15 Dai Showa Seishi Kk Glassine paper
DK0749473T3 (en) * 1994-03-08 2006-02-27 Novozymes As Hitherto unknown alkaline cellulases
KR100256636B1 (en) * 1994-04-12 2000-05-15 김충섭 Manufacturing method for improving the amount of fillers and reinforcing the strength of scott internal interrity in paper
EP1433843A3 (en) * 1995-12-18 2005-04-13 AB Enzymes Oy Novel xylanases, genes encoding them, and uses thereof
FR2765898B1 (en) * 1997-07-10 1999-10-01 Thibierge Et Comar COLOR TRACK PAPER

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4310249A1 (en) 2022-07-19 2024-01-24 SAPPI Netherlands Services B.V. Translucent paper products
WO2024017751A1 (en) 2022-07-19 2024-01-25 Sappi Netherlands Services B.V. Translucent paper products

Also Published As

Publication number Publication date
WO2008087337A3 (en) 2008-12-18
FR2910500A1 (en) 2008-06-27
ES2719628T3 (en) 2019-07-11
FR2910500B1 (en) 2010-01-01
WO2008087337A2 (en) 2008-07-24
EP2122053A2 (en) 2009-11-25

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