EP0050316B2 - Process for preparing a sheet material with retention by paper-making techniques - Google Patents

Process for preparing a sheet material with retention by paper-making techniques Download PDF

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Publication number
EP0050316B2
EP0050316B2 EP81108353A EP81108353A EP0050316B2 EP 0050316 B2 EP0050316 B2 EP 0050316B2 EP 81108353 A EP81108353 A EP 81108353A EP 81108353 A EP81108353 A EP 81108353A EP 0050316 B2 EP0050316 B2 EP 0050316B2
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Prior art keywords
binder
agent
process according
inorganic filler
weight
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EP81108353A
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German (de)
French (fr)
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EP0050316A1 (en
EP0050316B1 (en
Inventor
Daniel Gomez
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Papeteries de Gascogne SA
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Papeteries de Gascogne SA
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Application filed by Papeteries de Gascogne SA filed Critical Papeteries de Gascogne SA
Priority to AT81108353T priority Critical patent/ATE14765T1/en
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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
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/63—Inorganic compounds
    • D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
    • D21H17/69—Water-insoluble compounds, e.g. fillers, pigments modified, e.g. by association with other compositions prior to incorporation in the pulp or paper

Definitions

  • the present invention relates to a process for the preparation by paper techniques of a sheet material comprising, in addition to fibers, an organic binder, a non-binding mineral filler and a flocculant as well as various conventional adjuvants in stationery, aiming to improve the retention of the mineral load in the sheet, the formation of the sheet and its physical characteristics.
  • the invention also relates to a method making it possible to reduce pollution on the one hand, thanks to the reduction in the quantity of mineral materials which pass through the fabric of the paper machine and on the other hand, thanks to the re-use of coating baths in the bulk of the paper.
  • Papermaking processes are known for the production of sheet materials comprising fibers, non-binding mineral fillers, binders and flocculants. These processes use in situ precipitation techniques in the suspension comprising fibers, mineral fillers and binders using flocculants which can be introduced either before and after the binder, as in the published French patent applications n 2 410 084 and 2 429 293, or in the published European patent application No. 0 006 390, either after the binder as is common in stationery and described for example in the published French patent application No. 2 416 291.
  • the mineral fillers and organic binders customary in stationery and intended to be incorporated into the mass of paper are generally added to the fibers at successive stages in the preparation of the pulp.
  • the mineral particles are previously dispersed in aqueous lighthouse with a preferably anionic surfactant before being mixed with one or more types of organic binders.
  • the sleeping bath which is characterized by very good stability, an essential property for good regularity of the sleeping. is never injected into the mass.
  • the present invention relates to a continuous process for the preparation by paper techniques of a sheet material according to which an aqueous dispersion of particles of mineral filler coated with binder is subjected to ionic destabilization before mixing with the fibers. using a specific cationic flocculant.
  • the method of the invention thus allows better control of the flocculation and good regularity of the particle size of the flocs, which promotes the formation, the appearance, the surface uniformity and the inertia of the sheet.
  • the method according to the invention also makes it possible to improve the fiber-filler-binder connections, which results in the obtaining of improved physical characteristics of the sheet, in particular as regards internal cohesion, resistance to bursting and the holding of the sheet which becomes sufficient for very fast machines.
  • the method according to the invention allows the recycling of the coating baths in the bulk of the paper, which reduces pollution.
  • the anionic power of the latter is reinforced by adding, with stirring, a retention agent of anionic nature.
  • the method according to the invention makes it possible to prepare, with conventional means of manufacturing, surfacing or coating and finishing the stationery, a sheet material endowed with advantageous properties for printing-writing. impregnation, coating, packaging and obtaining complexes with various materials intended in particular for the food industry.
  • All the fibers are suitable for the production of the sheet material according to the invention, but preferably use is made of noble cellulose fibers, that is to say coming from resinous wood pulp and / or hardwood, possibly combined with recovered fibers, for example from old paper and textiles.
  • noble cellulose fibers that is to say coming from resinous wood pulp and / or hardwood
  • recovered fibers for example from old paper and textiles.
  • cellulosic fibers with fibers of high synthetic polymers such as polyamide or polyester fibers or with mineral fibers such as glass, ceramic, calcium sulphate fibers and carbon, or cellulose regeneration fibers, or mixtures thereof.
  • softwood pulps treated with soda bleached or unbleached will be preferred.
  • the non-binding mineral fillers that can be used in the process according to the invention are all the usual mineral fillers in stationery and in the paint industry such as, for example, talc, kaolin, natural calcium carbonate, precipitated or originating from operations. for the regeneration of black liquors extracted from the cooking of kraft pasta and more particularly after the caustification operation, magnesium carbonate, alumina hydrates, calcium sulphate, colloidal silica, barium sulphate, carbon dioxide titanium, satin white (hydrated calcium sulfoaluminate), magnesium hydroxide, or mixtures thereof.
  • talc or kaolin will preferably be chosen for acidic reasons (pH usual 4,5-6) or natural calcium carbonate precipitated or coming from the regeneration of kraft pulp cooking liquors in neutral or basic bonding (pH 6.5).
  • the quantity of mineral filler to be introduced in relation to the quantity of fibers can be very variable depending on the desired applications.
  • the quantity of fillers remaining in the sheet may vary from 5 to 40% by weight, and in particular from 10 to 30% by weight relative to the paper.
  • the loading rate may be greater than 50% by weight relative to the paper.
  • the quantity of remaining charges may vary between 2 and 15% by weight relative to the paper.
  • the organic binder which can be used in the process according to the invention is any organic binder, natural or synthetic, usually used in bulk stationery or in a coating bath. It ensures the connection of the constituents of the material together and makes it possible to improve the physical properties of the sheet material.
  • binders suitable in the process of the invention mention may be made of starches native or modified by chemical, enzymatic or thermal means, dextrins, polyvinyl alcohols, casein, animal glue, vegetable proteins, cellulose esters such as carboxymethylcellulose, alginates, dispersions of ready-to-use synthetic polymers such as carboxylated or non-carboxylated styrene-butadiene latexes, acrylic, styrene-acrylic latexes, vinyl acetates, neoprene latexes, latexes acrylonitrile, vinyl chloride latexes.
  • the amount of binder depends on the end use envisaged for the sheet material, but it can vary between 1 and 40 parts by weight, and preferably between 1 and 25 parts by weight, relative to 100 parts by weight of fibers. and charges.
  • an inorganic or organic destabilizing agent of the bath containing the mineral filler and the organic binder, also called flocculant.
  • This product is of the retention agent or cationic flocculant type chosen from those mentioned above.
  • the role of the flocculant is to precipitate the mineral filler and the organic binder before mixing with the fibers by ionic destabilization.
  • This flocculating agent also makes it possible to improve the wet strength of the sheet.
  • the fibrous suspension is added, before the incorporation of the flocculated charge-binder particles, an anionic retention agent in order to increase its anionic power.
  • an anionic retention agent it is possible to use, for example, a modified polyacrylamide of high molecular weight (5 ⁇ 10 6 to 10 7 ) or a sodium polyacrylate.
  • the role of the anionic retention agent associated with the binder flocculated on the filler is to reinforce the fiber-filler bonds in order to obtain, on the one hand, better retention on canvas and, on the other hand, an increase in the internal cohesion of the sheet. .
  • the amount of anionic retention agent depends on the anionicity of the paste used, which is linked to the manufacturing process (kraft or bisulfite paste) but also to the conditions for washing the paste before use.
  • a kraft pulp from an integrated factory has a much more anionic character than a dried and stored pulp before being sent to the paper machine.
  • 0.005 to 1 part by weight of anionic retention agent is used per 100 parts by weight of fibers.
  • the method according to the invention comprises the following stages.
  • the dough is conventionally refined to a Schoepper Riegler degree varying between 15 and 65 depending on the applications, at a variable concentration of between 20 and 60 g / I, using standard conical refiners or double discs, or else 250-350 gll with special refiners for high concentration refining, in particular in the case of the production of packaging supports, in order to obtain a high tear resistance.
  • the anionic retention agent in aqueous solution is added.
  • the mineral filler is dispersed in an aqueous medium in a tank at a variable concentration of between 400 and 600 g / l.
  • an inorganic dispersant such as sodium hexametaphosphate, or organic such as sodium polyacrylate in an amount between 0.02 and 1% compared to the mineral load. If talc is used as a mineral filler, this operation is not necessary because this filler can be very easily disintegrated in water at 150-600 g / l, without special additive.
  • This mixing operation with stirring can very easily be carried out continuously in a static conical or cylindrical type mixer with offset propeller (s) or in dynamic mixers, all the more so in these types of apparatus. it is also possible to adjust the dilution according to the desired concentration of the final bath, which is 50 to 200 g / l before flocculation.
  • the installation is not equipped with a mixer, it is recommended to homogenize the load-binder bath with 200-500 gll before diluting it between 100 and 350 gll.
  • the cationic flocculant is incorporated into the filler-binder suspension, preferably by metering pump, after having been previously diluted 1 to 10 times.
  • the mineral filler-organic binder flocs in aqueous suspension are then introduced continuously into the pulp of the first stage, before or after purification of the latter.
  • the other additives necessary for obtaining the final properties of the sheet material can be added either to the storage tank for the refined pulp, either continuously in the overhead circuit after the incorporation of the mineral filler and the flocculated organic binder.
  • the pH regulator and the sizing agent customary in stationery are preferably incorporated into the pulp after all the other adjuvants, which is usual in the manufacture of paper.
  • the mixture thus prepared is conveyed to the headbox and is then subjected to the usual treatments of the papermaking process such as draining, wet pressing, drying, possibly rubbing, surfacing on paper machine or outside machine, smoothing, calendering , coating, graining.
  • kraft packaging supports are prepared by methods of the prior art (examples 1 and 2) and by the method according to the invention (examples 3 and 4).
  • the percentage of ash remaining in the control medium is fixed at approximately 10%.
  • a control packaging kraft support is prepared using a binder and a flocculant which is added after the binder in the fibrous suspension, using the following constituents:
  • a kraft packaging support is prepared using the method according to the invention.
  • a first mixture of resinous wood pulp having an SR refining degree of 25 and an anionic retention agent is first prepared.
  • a second binder-mineral filler mixture is then prepared using the following constituents:
  • the binder is mixed with talc, dispersed, then 0.2 part by weight of polyethyleneimine in solution is added as a flocculant to the mixture.
  • the second mixture is incorporated into the first mixture.
  • a kraft packaging support is prepared according to the method of the invention in the same way as in Example 3, but by removing the anionic retention agent.
  • the internal cohesion of the sheet material prepared according to the method of the invention is approximately 10% greater than that obtained by the methods of the prior art.
  • a printing-writing medium bonded in a neutral medium having variable grammages is prepared according to a method of the prior art and according to the method of the invention.
  • a print-write control medium having a grammage of 100 g / m 2 , bonded in a neutral medium, is prepared using a process of the prior art according to which the flocculant is added to the fibrous suspension containing the mineral filler and the organic binder.
  • a mixture is obtained having the following composition:
  • a print-write control medium of the above type is prepared, but having a grammage of 200 g / M 2 .
  • a second binder-mineral filler mixture having the following composition is prepared:
  • the starch binder is mixed with the carbonate charge, dispersed, then 0.3 parts by weight of polyethylene imine in solution is added to flocculate the mixture.
  • the second mixture is incorporated into the first mixture, and then:
  • a print-write medium is prepared in the same way as in Example 7, this medium having a grammage of 200 g / m 2 .
  • This example illustrates the reuse of a bath commonly used in bedding in the process according to the invention.
  • the second mixture consists of a coating bath used for print-writing supports printable in offset.
  • This sleeping bath has the following composition:
  • the bath is diluted beforehand to 150 g 11 then, with stirring, the cationic flocculant previously diluted five times is incorporated, which consists of 0.15 part by weight of polyethylene imine in solution per 100 parts by weight of fillers and binder.
  • the second flocculated mixture is incorporated into the first mixture, then there is introduced:
  • the sheet formed is characterized by a rate of remaining charges of 26%, which indicates good retention on canvas, and by a high internal cohesion.

Abstract

1. Process for the preparation, by papermaking techniques, of a material in sheet form comprising fibres, a non-binding inorganic filler, a conventional organic papermaking binder and a flocculant, intended to improve the retention of the inorganic filler in the sheet, the formation of the sheet and its physical properties, characterised in that a homogeneous bath comprising the inorganic filler and the organic binder in prepared and this, before being introduced into the fibre suspension, is destabilised by means of a cationic flocculant chosen from among aqueous solutions of polyethyleneimine, polyamideamide crosslinked polyalkylamide, modified polyacrylamides, aluminium polychloride and cationic starches, as well as aqueous solutions of quaternary ammonium compounds such as hydroxypropyltrimethylammonium chloride.

Description

La présente invention concerne un procédé de préparation par des techniques papetiéres d'un matériau en feuille comprenant outre des fibres, un liant organique, une charge minérale non liante et un floculant ainsi que divers adjuvants classiques en papeterie, visant à améliorer la rétention de la charge minérale dans la feuille, la formation de la feuille et ses caractéristiques physiques.The present invention relates to a process for the preparation by paper techniques of a sheet material comprising, in addition to fibers, an organic binder, a non-binding mineral filler and a flocculant as well as various conventional adjuvants in stationery, aiming to improve the retention of the mineral load in the sheet, the formation of the sheet and its physical characteristics.

L'invention vise également un procédé permettant de diminuer la pollution d'une part, grâce à la réduction de la quantité de matières minérales qui traversent la toile de la machine à papier et d'autre part, grâce à la réutilisation de bains de couchage dans la masse du papier.The invention also relates to a method making it possible to reduce pollution on the one hand, thanks to the reduction in the quantity of mineral materials which pass through the fabric of the paper machine and on the other hand, thanks to the re-use of coating baths in the bulk of the paper.

Le coût de plus en plus élevé des fibres utilisées dans la production de matériaux en feuille ont conduit l'industrie papetière à remplacer les fibres par des charges minérales, qui peuvent être utilisées en quantités plus ou moins importantes.The increasing cost of fibers used in the production of sheet materials has led the paper industry to replace fibers with mineral fillers, which can be used in more or less quantities.

On connaît des procédés papetiers pour la fabrication de matériaux en feuille comprenant des fibres, des charges minérales non liantes, des liants et des floculants. Ces procédés font appel à des techniques de précipitation in situ dans la suspension comprenant les fibres, des charges minérales et des liants à l'aide de floculants qui peuvent être introduits soit avant et après le liant, comme dans les demandes de brevets français publiées n°2 410 084 et 2 429 293, ou dans la demande de brevet européen publiée n° 0 006 390, soit après le liant comme cela est courant en papeterie et décrit par exemple dans la demande de brevet français publiée n° 2 416 291.Papermaking processes are known for the production of sheet materials comprising fibers, non-binding mineral fillers, binders and flocculants. These processes use in situ precipitation techniques in the suspension comprising fibers, mineral fillers and binders using flocculants which can be introduced either before and after the binder, as in the published French patent applications n 2 410 084 and 2 429 293, or in the published European patent application No. 0 006 390, either after the binder as is common in stationery and described for example in the published French patent application No. 2 416 291.

Dans les procédés de ce type, les charges minérales et les liants organiques usuels en papeterie et destinés à être incorporés dans la masse du papier sont généralement ajoutés aux fibres à des stades successifs de la préparation de la pâte. Lorsque les charges minérales et les liants organiques sont utilisés pour les traitements de surface tels que le couchage sur machine ou hors machine, les particules minérales sont préalablement dispersées en phare aqueuse avec un tensio-actif préférentiellement anionique avant d'être mélangées à un ou plusieurs types de liants organiques. Le bain de couchage qui se caractérise par une très bonne stabilité, propriété indispensable à une bonne régularité du couchage. n'est jamais injecté dans la masse.In processes of this type, the mineral fillers and organic binders customary in stationery and intended to be incorporated into the mass of paper are generally added to the fibers at successive stages in the preparation of the pulp. When the mineral fillers and organic binders are used for surface treatments such as coating on or off the machine, the mineral particles are previously dispersed in aqueous lighthouse with a preferably anionic surfactant before being mixed with one or more types of organic binders. The sleeping bath which is characterized by very good stability, an essential property for good regularity of the sleeping. is never injected into the mass.

Il est également connu, d'après la demande de brevet allemand DE-A-2 041 406, d'ajouter à l'argile utilisée comme charge avant son mélange avec la colophane utilisée comme liant, une solution de sulfate d'aluminium afin d'abaisser le pH et d'obtenir ainsi une pâte adhérant bien aux fibres de la pâte à papier grâce à la précipitation de la coiophane sur les fibres en milieu acide.It is also known, according to German patent application DE-A-2 041 406, to add to the clay used as a filler before it is mixed with the rosin used as a binder, a solution of aluminum sulfate in order to '' lower the pH and thus obtain a pulp that adheres well to the pulp fibers thanks to the precipitation of the coiophane on the fibers in an acid medium.

La présente invention vise par contre un procédé en continu de préparation par des techniques papetières d'un matériau en feuille selon lequel on fait subir à une dispersion aqueuse de particules de charge minérale enrobées de liant, avant mélange avec les fibres, une déstabilisation ionique au moyen d'un floculant cationique spécifique.The present invention, however, relates to a continuous process for the preparation by paper techniques of a sheet material according to which an aqueous dispersion of particles of mineral filler coated with binder is subjected to ionic destabilization before mixing with the fibers. using a specific cationic flocculant.

Le procédé de l'invention permet ainsi un meilleur contrôle de la floculation et une bonne régularité de la granulométrie des flocs, ce qui favorise la formation, l'aspect, l'uni de surface et l'inertie de la feuille.The method of the invention thus allows better control of the flocculation and good regularity of the particle size of the flocs, which promotes the formation, the appearance, the surface uniformity and the inertia of the sheet.

Le procédé selon l'invention permet également d'améliorer les liaisons fibres-charge-liant ce qui aboutit à l'obtention de caractéristiques physiques de la feuille améliorées, notamment en ce qui concerne la cohésion interne, la résistance à l'éclatement et la tenue de la feuille qui devient suffisante pour des machines très rapides.The method according to the invention also makes it possible to improve the fiber-filler-binder connections, which results in the obtaining of improved physical characteristics of the sheet, in particular as regards internal cohesion, resistance to bursting and the holding of the sheet which becomes sufficient for very fast machines.

Grâce au procédé selon l'invention, la rétention des charges minérales dans la feuille est fortement améliorée.Thanks to the method according to the invention, the retention of mineral fillers in the sheet is greatly improved.

En outre, le procédé selon l'invention permet le recyclage des bains de couchage dans la masse du papier, ce qui diminue la pollution.In addition, the method according to the invention allows the recycling of the coating baths in the bulk of the paper, which reduces pollution.

La présente invention a donc pour objet un procédé en continu de préparation par des techniques papetières d'un matériau en feuille, selon lequel on réalise les opérations suivantes, dans l'ordre cité ci-dessous :

  • 1 ) on prépare une dispersion aqueuse de particules de charge minérale choisie parmi les charges usuelles en papeterie ;
  • 2) on mélange à cette dispersion aqueuse de charge un liant organique classique de la papeterie, sous agitation, jusqu'à obtenir une dispersion aqueuse de particules de charge minérale enrobée de liant ;
  • 3) on fait subir à cette dispersion aqueuse de particules de charge minérale enrobées de liant, sous agitation, avant mélange avec les fibres, une déstabilisation ionique au moyen d'un floculant cationique choisi parmi les solutions aqueuses de polyéthylèneimine, de polyamide-amine, de polyalkylamine réticulée, de polyacrylamides modifiés, le polychlorure d'aluminium, ainsi que les solutions aqueuses d'ammonium quaternaire, le floculant cationique étant utilisé en une quantité réglée pour que la floculation totale se réalise en une minute au maximum ;
  • 4) on introduit les flocs charge minérale-liant organique en suspension aqueuse dans la suspension fibreuse.
The subject of the present invention is therefore a continuous process for preparing a sheet material by paper techniques, according to which the following operations are carried out, in the order mentioned below:
  • 1) an aqueous dispersion of particles of mineral filler chosen from the usual fillers in stationery is prepared;
  • 2) a conventional organic binder from the paper mill is mixed with this aqueous dispersion of filler, with stirring, until an aqueous dispersion of particles of mineral filler coated with binder is obtained;
  • 3) this aqueous dispersion is subjected to particles of mineral filler coated with binder, with stirring, before mixing with the fibers, an ionic destabilization by means of a cationic flocculant chosen from aqueous solutions of polyethyleneimine, of polyamide-amine, crosslinked polyalkylamine, modified polyacrylamides, polychloride of aluminum, as well as aqueous solutions of quaternary ammonium, the cationic flocculant being used in a regulated quantity so that the total flocculation is carried out in one minute at most;
  • 4) the mineral filler-organic binder flocs in aqueous suspension are introduced into the suspension fibrous.

Selon un mode préféré du procédé de l'invention, avant d'incorporer les flocs charge minérale-liant organique dans la suspension fibreuse, on renforce le pouvoir anionique de cette dernière en ajoutant, sous agitation, un agent de rétention à caractère anionique.According to a preferred mode of the process of the invention, before incorporating the mineral filler-organic binder flocs in the fibrous suspension, the anionic power of the latter is reinforced by adding, with stirring, a retention agent of anionic nature.

Le procédé selon l'invention permet de préparer avec des moyens classiques de fabrication, de surfaçage ou de couchage et de finissage de la papeterie, un matériau en feuille doué de propriétés intéressantes pour l'impression-écriture. l'imprégnation, l'enduction, l'emballage et l'obtention de complexes avec divers matériaux destinés notamment à l'industrie alimentaire.The method according to the invention makes it possible to prepare, with conventional means of manufacturing, surfacing or coating and finishing the stationery, a sheet material endowed with advantageous properties for printing-writing. impregnation, coating, packaging and obtaining complexes with various materials intended in particular for the food industry.

Toutes les fibres conviennent pour la fabrication du matériau en feuille selon l'invention, mais on utilise de préférence les fibres cellulosiques nobles, c'est-à-dire provenant de pâte de bois résineux et/ou de bois feuillus, éventuellement associées à des fibres de récupération provenant par exemple de vieux papiers et de textiles. Pour certaines applications spéciales, il est également possible de combiner les fibres cellulosiques à des fibres de hauts polymères synthétiques telles que les fibres de polyamides ou de polyesters ou à des fibres minérales telles que les fibres de verre, de céramique, de sulfate de calcium et de carbone, ou encore à des fibres de régénération de la cellulose, ou à leurs mélanges.All the fibers are suitable for the production of the sheet material according to the invention, but preferably use is made of noble cellulose fibers, that is to say coming from resinous wood pulp and / or hardwood, possibly combined with recovered fibers, for example from old paper and textiles. For certain special applications, it is also possible to combine cellulosic fibers with fibers of high synthetic polymers such as polyamide or polyester fibers or with mineral fibers such as glass, ceramic, calcium sulphate fibers and carbon, or cellulose regeneration fibers, or mixtures thereof.

Pour une application impression-écriture ou pour les revêtements muraux, on choisira par exemple des combinaisons de pâtes de bois résineux traitées à la soude ou au bisulfite, mi-blanchies ou blanchies.For a print-write application or for wall coverings, for example, choose combinations of resinous wood pulp treated with soda or bisulfite, semi-bleached or bleached.

Pour l'emballage ou pour l'obtention de complexes alimentaires, on préférera des pâtes de bois résineux traitées à la soude blanchies ou écrues.For packaging or for obtaining food complexes, softwood pulps treated with soda bleached or unbleached will be preferred.

Les charges minérales non liantes pouvant être utilisées dans le procédé selon l'invention sont toutes les charges minérales usuelles en papeterie et dans l'industrie des peintures comme par exemple le talc, le kaolin, le carbonate de calcium naturel, précipité ou provenant des opérations de régénération des liqueurs noires extraites de la cuisson des pâtes kraft et plus particulièrement après l'opération de caustification, le carbonate de magnésium, les hydrates d'alumine, le sulfate de calcium, la silice colloïdale, le sulfate de baryum, le dioxyde de titane, le blanc satin (sulfoaluminate de calcium hydraté), l'hydroxyde de magnésium, ou leurs mélanges.The non-binding mineral fillers that can be used in the process according to the invention are all the usual mineral fillers in stationery and in the paint industry such as, for example, talc, kaolin, natural calcium carbonate, precipitated or originating from operations. for the regeneration of black liquors extracted from the cooking of kraft pasta and more particularly after the caustification operation, magnesium carbonate, alumina hydrates, calcium sulphate, colloidal silica, barium sulphate, carbon dioxide titanium, satin white (hydrated calcium sulfoaluminate), magnesium hydroxide, or mixtures thereof.

Pour des applications classiques en impression-écriture, emballage ou pour les supports d'enduction en phase aqueuse, à l'aide de solvants ou pour plastisols, on choisira de préférence pour des raisons économiques, le talc ou le kaolin en collage acide (pH habituel 4,5-6) ou le carbonate de calcium naturel précipité ou provenant de la régénération des liqueurs de cuisson de pâte kraft en collage neutre ou basique (pH 6,5).For conventional applications in print-writing, packaging or for coating media in the aqueous phase, using solvents or plastisols, talc or kaolin will preferably be chosen for acidic reasons (pH usual 4,5-6) or natural calcium carbonate precipitated or coming from the regeneration of kraft pulp cooking liquors in neutral or basic bonding (pH 6.5).

La quantité de charge minérale à introduire par rapport à la quantité de fibres peut être très variable en fonction des applications désirées.The quantity of mineral filler to be introduced in relation to the quantity of fibers can be very variable depending on the desired applications.

Par exemple, en impression-écriture, la quantité de charges restantes dans la feuille pourra varier de 5 à 40 % en poids, et notamment de 10 à 30 % en poids par rapport au papier. Pour les revêtements divers destinés au bâtiment, le taux de charge pourra être supérieur à 50% en poids par rapport au papier. Pour des applications emballages du type sac de petite, moyenne grande contenance ou pour des enveloppes kraft ou les supports bande adresse par exemple, la quantité de charges restantes pourra varier entre 2 et 15 % en poids par rapport au papier.For example, in printing-writing, the quantity of fillers remaining in the sheet may vary from 5 to 40% by weight, and in particular from 10 to 30% by weight relative to the paper. For various coatings intended for the building, the loading rate may be greater than 50% by weight relative to the paper. For packaging applications of the small, medium large capacity bag type or for kraft envelopes or address tape supports for example, the quantity of remaining charges may vary between 2 and 15% by weight relative to the paper.

Le liant organique pouvant être utilisé dans le procédé suivant l'invention est un liant organique quelconque, naturel ou synthétique, utilisé habituellement en papeterie dans la masse ou dans un bain de couchage. Il assure la liaison des constituants du matériau entre eux et permet d'améliorer les propriétés physiques du matériau en feuille. A titre de liants convenant dans le procédé de l'invention, on peut citer les amidons natifs ou modifiés par voie chimique, enzymatique ou thermique, les dextrines, les alcools polyvinyliques, la caséine, la colle animale, les protéines végétales, les esters cellulosiques comme la carboxyméthylcellulose, les alginates, les dispersions de polymères synthétiques prêtes à l'emploi comme les latex styrène-butadiène carboxylés ou non carboxylés, les latex acryliques, styrène-acryliques, les acétates de vinyle, les latex de néoprène, les latex d'acrylonitrile, les latex de chlorure de vinyle.The organic binder which can be used in the process according to the invention is any organic binder, natural or synthetic, usually used in bulk stationery or in a coating bath. It ensures the connection of the constituents of the material together and makes it possible to improve the physical properties of the sheet material. As binders suitable in the process of the invention, mention may be made of starches native or modified by chemical, enzymatic or thermal means, dextrins, polyvinyl alcohols, casein, animal glue, vegetable proteins, cellulose esters such as carboxymethylcellulose, alginates, dispersions of ready-to-use synthetic polymers such as carboxylated or non-carboxylated styrene-butadiene latexes, acrylic, styrene-acrylic latexes, vinyl acetates, neoprene latexes, latexes acrylonitrile, vinyl chloride latexes.

La quantité de liant est fonction de l'usage final envisagé pour le matériau en feuille, mais elle peut varier entre 1 et 40 parties en poids, et de préférence entre 1 et 25 parties en poids, par rapport à 100 parties en poids de fibres et de charges.The amount of binder depends on the end use envisaged for the sheet material, but it can vary between 1 and 40 parts by weight, and preferably between 1 and 25 parts by weight, relative to 100 parts by weight of fibers. and charges.

Selon une autre caractéristique du procédé de l'invention, on utilise un agent de déstabilisation minéral ou organique du bain renfermant la charge minérale et le liant organique, encore appelé floculant. Ce produit est du type agent de rétention ou floculant cationique choisi parmi ceux mentionnés ci-dessus. Le floculant a pour rôle de précipiter la charge minérale et le liant organique avant mélange avec les fibres par déstabilisation ionique. Cet agent de floculation permet aussi d'améliorer la résistance à l'état humide de la feuille.According to another characteristic of the process of the invention, an inorganic or organic destabilizing agent of the bath is used containing the mineral filler and the organic binder, also called flocculant. This product is of the retention agent or cationic flocculant type chosen from those mentioned above. The role of the flocculant is to precipitate the mineral filler and the organic binder before mixing with the fibers by ionic destabilization. This flocculating agent also makes it possible to improve the wet strength of the sheet.

L'agent de floculation est incorporé en continu dans la suspension aqueuse renfermant la charge minérale et le liant organique, en une quantité généralement comprise entre 0,006 et 5 parties en poids, et de préférence entre 0,01 et 2 parties en poids pour 100 parties de charge minérale et de liant. La quantité exacte à utiliser dépend de quatre facteurs :

  • - la concentration de la suspension aqueuse de charge et de liant ;
  • - le temps de contact floculant-charge-liant, qui est lié à la configuration des circuits de tête de la machine à papier ;
  • - l'agitation ;
  • - le pouvoir cationique du floculant.
The flocculating agent is incorporated continuously into the aqueous suspension containing the mineral filler and the organic binder, in an amount generally between 0.006 and 5 parts by weight, and preferably between 0.01 and 2 parts by weight per 100 parts mineral filler and binder. The exact amount to use depends on four factors:
  • - Concentration of the aqueous suspension of filler and binder;
  • - the flocculant-filler-binder contact time, which is linked to the configuration of the paper machine's head circuits;
  • - agitation;
  • - the cationic power of the flocculant.

Cependant, cette quantité est réglée pour que la floculation totale se réalise en une minute au maximum.However, this amount is adjusted so that total flocculation takes place in a maximum of one minute.

Selon un mode de réalisation préféré du procédé de l'invention, on ajoute la suspension fibreuse, avant l'incorporation des particules floculées charge-liant, un agent de rétention anionique afin d'augmenter son pouvoir anionique. En tant qu'agent de rétention anionique, on peut utiliser par exemple un polyacrylamide modifié de poids moléculaire élevé (5 x 106 à 107) ou un polyacrylate de sodium.According to a preferred embodiment of the process of the invention, the fibrous suspension is added, before the incorporation of the flocculated charge-binder particles, an anionic retention agent in order to increase its anionic power. As an anionic retention agent, it is possible to use, for example, a modified polyacrylamide of high molecular weight (5 × 10 6 to 10 7 ) or a sodium polyacrylate.

L'agent de rétention anionique associé au liant floculé sur la charge a pour rôle de renforcer les liaisons fibres-charge afin d'obtenir d'une part une meilleure rétention sur toile et d'autre part une augmentation de la cohésion interne de la feuille.The role of the anionic retention agent associated with the binder flocculated on the filler is to reinforce the fiber-filler bonds in order to obtain, on the one hand, better retention on canvas and, on the other hand, an increase in the internal cohesion of the sheet. .

La quantité d'agent de rétention anionique est fonction de l'anionicité de la pâte utilisée, qui est liée au procédé de fabrication (pâte kraft ou bisulfite) mais aussi aux conditions de lavage de la pâte avant utilisation. Une pâte kraft provenant d'une usine intégrée possède un caractère anionique beaucoup plus marqué qu'une pâte séchée et stockée avant d'être envoyée sur la machine à papier. On utilisera avantageusement 0,005 à 1 partie en poids d'agent de rétention anionique pour 100 parties en poids de fibres.The amount of anionic retention agent depends on the anionicity of the paste used, which is linked to the manufacturing process (kraft or bisulfite paste) but also to the conditions for washing the paste before use. A kraft pulp from an integrated factory has a much more anionic character than a dried and stored pulp before being sent to the paper machine. Advantageously, 0.005 to 1 part by weight of anionic retention agent is used per 100 parts by weight of fibers.

Outre les fibres, la charge minérale, le liant organique et les floculants anionique et cationique, on peut utiliser dans le procédé de préparation d'un matériau en feuille selon l'invention divers adjuvants classiques en papeterie tels que:

  • - Un agent de collage utilisé habituellement en papeterie pour réduire la sensibilité à l'eau de la feuille, tel que les colophanes modifiées, les émulsions de paraffine, les alkylcétènes dimères.
  • - Un agent de régulation du pH, par exemple le sulfate d'aluminium ou l'acide sulfurique destiné a régler le pH à 4,5-6 pour un collage en milieu acide.
  • - Un agent anti-mousse.
  • - Un azurant optique.
  • - Un agent de coloration ou de nuançage.
  • - Un agent de résistance à l'état humide comme l'urée-formol, la mélamine-formol, le glyoxal, les polyalky- lènes amines cationiques réticulées, les produits de condensation mélamine-formaldéhyde et acide ami- no-caproique.
  • - Un agent fongicide et/ou bactéricide ainsi que des additifs auxiliaires classiques des bains de couchage impression-écriture comme:
  • - un agent dispersant tel que l'hexamétaphosphate ou le pyrophosphate de sodium, la soude ou le polyacrylate de sodium ;
  • - un agent lubrifiant tel que les dérivés d'acide gras, par exemple le stéreate de sodium ou de calcium ;
  • - un régulateur de viscosité tel que la gélatine, la carboxyméthylcellulose, le polyacrylate d'ammonium, le silicate de sodium, l'éthylènediamine ou l'urée.
In addition to the fibers, the mineral filler, the organic binder and the anionic and cationic flocculants, it is possible to use in the process for the preparation of a sheet material according to the invention various conventional additives in stationery such as:
  • - A sizing agent usually used in stationery to reduce the water sensitivity of the sheet, such as modified rosins, paraffin emulsions, dimeric alkyl ketenes.
  • - A pH regulating agent, for example aluminum sulphate or sulfuric acid intended to adjust the pH to 4.5-6 for bonding in an acid medium.
  • - An anti-foaming agent.
  • - An optical brightener.
  • - A coloring or shading agent.
  • - A wet strength agent such as urea-formaldehyde, melamine-formaldehyde, glyoxal, crosslinked cationic polyalkylene amines, melamine-formaldehyde condensation products and amino-caproic acid.
  • - A fungicidal and / or bactericidal agent as well as conventional auxiliary additives in printing-writing coating baths such as:
  • - a dispersing agent such as hexametaphosphate or sodium pyrophosphate, soda or sodium polyacrylate;
  • - a lubricating agent such as fatty acid derivatives, for example sodium or calcium stereate;
  • - a viscosity regulator such as gelatin, carboxymethylcellulose, ammonium polyacrylate, sodium silicate, ethylenediamine or urea.

Selon un mode de réalisation préféré, le procédé selon l'invention comprend les stades suivants.According to a preferred embodiment, the method according to the invention comprises the following stages.

1 el Stade1 st Stadium

1) Les fibres en suspension aqueuse provenant soit du défibrage dans un pulpeur (usine non intégrée), soit directement de l'usine de pâte (usine intégrée) sont stockées à 40-100 gll sous agitation dans un cuvier.1) The fibers in aqueous suspension coming either from defibration in a pulper (non-integrated factory), or directly from the pulp factory (integrated factory) are stored at 40-100 gll with stirring in a vat.

2) La pâte est raffinée de façon classique à un degré Schoepper Riegler variant entre 15 et 65 selon les applications, à une concentration variable comprise entre 20 et 60 g/I, à l'aide de raffineurs coniques ou double disques standards, ou bien à 250-350 gll avec des raffineurs spéciaux pour raffinage haute concentration, notamment dans le cas de la fabrication de supports d'emballage, afin d'obtenir une résistance élevée à la déchirure.2) The dough is conventionally refined to a Schoepper Riegler degree varying between 15 and 65 depending on the applications, at a variable concentration of between 20 and 60 g / I, using standard conical refiners or double discs, or else 250-350 gll with special refiners for high concentration refining, in particular in the case of the production of packaging supports, in order to obtain a high tear resistance.

3) On ajoute éventuellement, sous agitation, l'agent de rétention anionique en solution aqueuse.3) Optionally, with stirring, the anionic retention agent in aqueous solution is added.

2e Stade2nd Stage

1) Préparation de la suspension charge minérale-liant organique.1) Preparation of the mineral filler-organic binder suspension.

La charge minérale est dispersée en milieu aqueux dans une cuve à une concentration variable comprise entre 400 et 600 g/l. Selon la nature de la charge et pour favoriser l'homogénéité de la dispersion afin d'éviter la formation d'agrégats, il est parfois avantageux d'employer un dispersant minéral tel que l'hexamé- taphosphate de sodium, ou organique tel que le polyacrylate de sodium en une quantité comprise entre 0,02 et 1 % par rapport à la charge minérale. Si l'on utilise le talc en tant que charge minérale, cette opération n'est pas nécessaire car cette charge peut être délitée très facilement dans l'eau à 150-600 g/l, sans additif spécial.The mineral filler is dispersed in an aqueous medium in a tank at a variable concentration of between 400 and 600 g / l. Depending on the nature of the filler and to promote the homogeneity of the dispersion in order to avoid the formation of aggregates, it is sometimes advantageous to use an inorganic dispersant such as sodium hexametaphosphate, or organic such as sodium polyacrylate in an amount between 0.02 and 1% compared to the mineral load. If talc is used as a mineral filler, this operation is not necessary because this filler can be very easily disintegrated in water at 150-600 g / l, without special additive.

2) Le liant organique prêt à l'emploi s'il s'agit par exemple d'un latex ou après cuisson s'il s'agit d'amidons natifs, oxydés ou éthérifiés, de dextrines, ou d'esters d'amidons, ou après enzymation s'il s'agit d'un amidon natif, est mélangé à la charge délitée sous agitation. Cette opération de mélange sous agitation peut très facilement se réaliser en continu dans un mélangeur statique type conique ou cylindrique à hélice(s) décalée(s) ou dans des mélangeurs dynamiques, d'autant plus que dans ces types d'appareils, il est également possible de régler la dilution en fonction de la concentration souhaitée du bain final, qui est de 50 à 200 g/l avant floculation.2) The organic binder ready to use if it is for example a latex or after baking if it is native, oxidized or etherified starches, dextrins, or esters of starches , or after enzymation if it is a native starch, is mixed with the disintegrated charge with stirring. This mixing operation with stirring can very easily be carried out continuously in a static conical or cylindrical type mixer with offset propeller (s) or in dynamic mixers, all the more so in these types of apparatus. it is also possible to adjust the dilution according to the desired concentration of the final bath, which is 50 to 200 g / l before flocculation.

Si l'installation n'est pas équipée d'un mélangeur, il est recommandé d'homogénéiser le bain charge-liant à 200-500 gll avant de le diluer entre 100 et 350 gll.If the installation is not equipped with a mixer, it is recommended to homogenize the load-binder bath with 200-500 gll before diluting it between 100 and 350 gll.

3) Le floculant cationique est incorporé dans la suspension charge-liant, de préférence par pompe doseuse, après avoir été préalablement dilué 1 à 10 fois.3) The cationic flocculant is incorporated into the filler-binder suspension, preferably by metering pump, after having been previously diluted 1 to 10 times.

3e Stade 3rd Stage

Les flocs charge minérale-liant organique en suspension aqueuse sont alors introduits en continu dans la pâte du premier stade, avant ou après épuration de cette dernière.The mineral filler-organic binder flocs in aqueous suspension are then introduced continuously into the pulp of the first stage, before or after purification of the latter.

4e Stade4th Stage

Les autres additifs nécessaires pour l'obtention des propriétés finales du matériau en feuille, tels que les azurants optiques, les agents de résistance à l'état humide, etc... peuvent être ajoutés soit dans le cuvier de stockage de la pâte raffinée, soit en continu dans le circuit de tête après l'incorporation de la charge minérale et du liant organique floculés.The other additives necessary for obtaining the final properties of the sheet material, such as optical brighteners, resistance agents in the wet state, etc. can be added either to the storage tank for the refined pulp, either continuously in the overhead circuit after the incorporation of the mineral filler and the flocculated organic binder.

Toutefois, le régulateur de pH et l'agent de collage usuel en papeterie sont de préférence incorporés dans la pâte après tous les autres adjuvants, ce qui est habituel dans la fabrication du papier.However, the pH regulator and the sizing agent customary in stationery are preferably incorporated into the pulp after all the other adjuvants, which is usual in the manufacture of paper.

Le cas échéant il est possible également, comme cela se fait couramment en papeterie, en particulier lorsque les taux de charges sont très élevés, d'incorporer un agent de rétention classique avant la caisse de tête.If necessary, it is also possible, as is commonly done in stationery, in particular when the charge rates are very high, to incorporate a conventional retention agent before the headbox.

Le mélange ainsi préparé est véhiculé vers la caisse de tête et est soumis ensuite aux traitements usuels du procédé de fabrication du papier tels que égouttage, pressage humide, séchage, éventuellement friction- nage, surfaçage sur machine à papier ou hors machine, lissage, calandrage, couchage, grainage.The mixture thus prepared is conveyed to the headbox and is then subjected to the usual treatments of the papermaking process such as draining, wet pressing, drying, possibly rubbing, surfacing on paper machine or outside machine, smoothing, calendering , coating, graining.

Les exemples qui suivent, donnés à titre d'illustration et nullement limitatifs de la portée de la présente invention, permettront de mieux comprendre les avantages du procédé selon l'invention.The examples which follow, given by way of illustration and in no way limit the scope of the present invention, will make it possible to better understand the advantages of the method according to the invention.

Exemples 1 à 4Examples 1 to 4

On prépare plusieurs supports kraft d'emballage par des procédés de l'art antérieur (exemples 1 et 2) et par le procédé selon l'invention (exemples 3 et 4). Le taux de cendres restantes du support témoin est fixé à environ 10 %.Several kraft packaging supports are prepared by methods of the prior art (examples 1 and 2) and by the method according to the invention (examples 3 and 4). The percentage of ash remaining in the control medium is fixed at approximately 10%.

Exemple 1Example 1

On prépare un support kraft d'emballage témoin en n'utilisant ni liant, ni floculant, à l'aide des constituants suivants :

Figure imgb0001

  • * Pâte de bois résineux traitée à la soude et écrue.
A control packaging kraft support is prepared by using neither binder nor flocculant, using the following constituents:
Figure imgb0001
  • * Softwood pulp treated with soda and unbleached.

Exemple 2Example 2

On prépare un support kraft d'emballage témoin en utilisant un liant et un floculant qui est ajouté après le liant dans la suspension fibreuse, à l'aide des constituants suivants :

Figure imgb0002
A control packaging kraft support is prepared using a binder and a flocculant which is added after the binder in the fibrous suspension, using the following constituents:
Figure imgb0002

Exemple 3Example 3

On prépare un support kraft d'emballage en utilisant le procédé selon l'invention.A kraft packaging support is prepared using the method according to the invention.

On prépare d'abord un premier mélange de pâte de bois résineux ayant un degré de raffinage SR de 25 et d'un agent de rétention anionique.A first mixture of resinous wood pulp having an SR refining degree of 25 and an anionic retention agent is first prepared.

Ce premier mélange à la composition suivante:

Figure imgb0003
This first mixture with the following composition:
Figure imgb0003

On prépare ensuite un second mélange liant-charge minérale à l'aide des constituants suivants :

Figure imgb0004
A second binder-mineral filler mixture is then prepared using the following constituents:
Figure imgb0004

Le liant est mélangé au talc, dispersé, puis on ajoute au mélange 0,2 partie en poids de polyéthylèneimine en solution à titre de floculant.The binder is mixed with talc, dispersed, then 0.2 part by weight of polyethyleneimine in solution is added as a flocculant to the mixture.

On incorpore le second mélange au premier mélange.The second mixture is incorporated into the first mixture.

On ajoute ensuite :

Figure imgb0005
Then we add:
Figure imgb0005

Exemple 4Example 4

On prépare un support kraft d'emballage selon le procédé de l'invention de la même façon que dans l'exemple 3, mais en supprimant l'agent de rétention anionique.A kraft packaging support is prepared according to the method of the invention in the same way as in Example 3, but by removing the anionic retention agent.

Les caractéristiques des supports kraft d'emballage obtenus dans les exemples 1 à 4 sont rassemblées dans le tableau 1 qui suit. (Voir Tableau 1 page 7)

Figure imgb0006
The characteristics of the kraft packaging supports obtained in Examples 1 to 4 are collated in Table 1 which follows. (See Table 1 page 7)
Figure imgb0006

Il ressort des résultats indiqués dans le tableau 1 que la préfloculation selon l'invention de la charge et du liant avant leur incorporation dans la suspension fibreuse améliore fortement le pourcentage de rétention globale des charges minérales dans le support ainsi que certaines caractéristiques physiques du support, notamment la longueur de rupture moyenne, l'indice d'éclatement moyen et le taux de cendres minérales resfantes.It appears from the results indicated in Table 1 that the preflocculation according to the invention of the filler and of the binder before their incorporation into the fibrous suspension greatly improves the percentage of overall retention of the mineral fillers in the support as well as certain physical characteristics of the support, in particular the average rupture length, the average burst index and the rate of resfantes mineral ash.

On voit également que la rétention est d'autant meilleure que la pâte contient un agent de rétention anionique.It is also seen that the retention is all the better as the paste contains an anionic retention agent.

En outre, la cohésion interne du matériau en feuille préparé selon le procédé de l'invention est supérieure d'environ 10 % à celle obtenue par les procédés de l'art antérieur.In addition, the internal cohesion of the sheet material prepared according to the method of the invention is approximately 10% greater than that obtained by the methods of the prior art.

Exemple 5 à 8Example 5 to 8

On prépare selon un procédé de l'art antérieur et selon le procédé de l'invention un support d'impression-écriture collé en milieu neutre ayant des grammages variables.A printing-writing medium bonded in a neutral medium having variable grammages is prepared according to a method of the prior art and according to the method of the invention.

Exemple 5Example 5

On prépare un support témoin d'impression-écriture ayant un grammage de 100 g/m2, collé en milieu neutre, en utilisant un procédé de l'art antérieur selon lequel on ajoute le floculant dans la suspension fibreuse contenant la charge minérale et le liant organique.A print-write control medium having a grammage of 100 g / m 2 , bonded in a neutral medium, is prepared using a process of the prior art according to which the flocculant is added to the fibrous suspension containing the mineral filler and the organic binder.

On obtient un mélange ayant la composition suivante :

Figure imgb0007
A mixture is obtained having the following composition:
Figure imgb0007

Exemple 6Example 6

On prépare un support témoin d'impression-écriture du type précédent, mais ayant un grammage de 200 g/M2.A print-write control medium of the above type is prepared, but having a grammage of 200 g / M 2 .

Exemple 7Example 7

On prépare un support d'impression-écriture collé en milieu neutre, ayant un grammage de 100 g/m2, selon le procédé de l'invention.A print-write support bonded in a neutral medium, having a grammage of 100 g / m 2 , is prepared according to the method of the invention.

On prépare d'abord un premier mélange ayant la composition suivante :

Figure imgb0008
First preparing a first mixture having the following composition:
Figure imgb0008

On prépare un second mélange liant-charge minérale ayant la composition suivante :

Figure imgb0009
A second binder-mineral filler mixture having the following composition is prepared:
Figure imgb0009

Le liant d'amidon est mélangé à la charge de carbonate, dispersé, puis on ajoute pour floculer le mélange 0,3 partie en poids de polyéthylène imine en solution.The starch binder is mixed with the carbonate charge, dispersed, then 0.3 parts by weight of polyethylene imine in solution is added to flocculate the mixture.

Le second mélange est incorporé au premier mélange, puis on introduit :

Figure imgb0010
The second mixture is incorporated into the first mixture, and then:
Figure imgb0010

Exemple 8Example 8

On prépare un support d'impression-écriture de la même façon que dans l'exemple 7, ce support ayant un grammage de 200 g/m2.A print-write medium is prepared in the same way as in Example 7, this medium having a grammage of 200 g / m 2 .

Les caractéristiques des supports d'impression-écriture obtenus dans les exemples 5 à 8 sont rassemblées dans le tableau 2 suivant.

Figure imgb0011
The characteristics of the print-write supports obtained in Examples 5 to 8 are collated in Table 2 below.
Figure imgb0011

Il ressort des résultats indiqués dans le tableau ci-dessus que le procédé selon l'invention permet d'améliorer le pourcentage de rétention globale des charges minérales dans le support et la solidité de ce dernier puisque, à taux de cendres plus élevé, les caractéristiques mécaniques des supports selon l'invention sont sensiblement équivalentes à celles des témoins.It appears from the results indicated in the table above that the method according to the invention makes it possible to improve the percentage of overall retention of mineral fillers in the support and the solidity of the latter since, at a higher ash rate, the characteristics mechanical supports according to the invention are substantially equivalent to those of the controls.

Exemple 9Example 9

Cet exemple illustre la réutilisation d'un bain couramment utilisé en couchage dans le procédé selon l'invention.This example illustrates the reuse of a bath commonly used in bedding in the process according to the invention.

On prépare un premier mélange ayant la composition suivante :

Figure imgb0012

  • * Pâte de bois résineux traitée au bisulfite et blanchie.
  • ** Pâte de bois feuillus traitée au bisulfite et blanchie.
A first mixture is prepared having the following composition:
Figure imgb0012
  • * Softwood pulp treated with bisulfite and bleached.
  • ** Pulp of hardwood treated with bisulfite and bleached.

Le second mélange est constitué par un bain de couchage utilisé pour des supports d'impression-écriture imprimables en offset. Ce bain de couchage a la composition suivante :

Figure imgb0013
The second mixture consists of a coating bath used for print-writing supports printable in offset. This sleeping bath has the following composition:
Figure imgb0013

On dilue préalablement le bain à 150g11 puis, sous agitation, on incorpore le floculant cationique préalablement dilué cinq fois, qui est constitué par 0,15 partie en poids de polyéthylène imine en solution pour 100 parties en poids de charges et de liant.The bath is diluted beforehand to 150 g 11 then, with stirring, the cationic flocculant previously diluted five times is incorporated, which consists of 0.15 part by weight of polyethylene imine in solution per 100 parts by weight of fillers and binder.

On incorpore le second mélange floculé au premier mélange, puis on introduit :

Figure imgb0014
The second flocculated mixture is incorporated into the first mixture, then there is introduced:
Figure imgb0014

La feuille formée se caractérise par un taux de charges restantes de 26 %, ce qui indique une bonne rétention sur toile, et par une cohésion interne élevée.The sheet formed is characterized by a rate of remaining charges of 26%, which indicates good retention on canvas, and by a high internal cohesion.

Claims (11)

1. Continuous process for the preparation, by papermaking techniques, of a sheet material, characterised in that the following operations are carried out in the order mentioned below:
1) an aqueous dispersion is prepared of particles of inorganic filler chosen from the usual papermaking fillers;
2) a conventional organic papermaking binder is mixed with this aqueous filler dispersion, with stirring, until an aqueous dispersion of inorganic filler particles which are coated with binder is obtained;
3) this aqueous dispersion of inorganic filler particles coated with binder is subjected, with stirring, before mixing with the fibres, to an ionic destabilisation by means of a cationic flocculant chosen from aqueous solutions of polyethyleneimine, of polyamideamine, of crosslinked polyalkylamine, of modified polyacrylamides, aluminium polychloride and aqueous quaternary ammonium solutions, the cationic flocculant being employed in a quantity adjusted so that complete flocculation is produced in one minute at most;
4) the inorganic filler-organic binderflocs in aqueous suspension are introduced into the fibre suspension.
2. Process according to Claim 1, characterised in that, before incorporating the inorganic filler-organic binderflocs into the fibre suspension, the anionicity of the latter is strengthened by adding, with stirring, a retention agent of an anionic nature.
3. Process according to Claim 1 or 2, characterised in that the ionic destabilisation of the filler-binder aqueous dispersion is obtained by introducing into this dispersion a cationic flocculant diluted 1 to 10-fold beforehand.
4. Process according to any one of Claims 1 to 3, characterised in that the inorganic filler is chosen from talc, kaolin and natural or precipitated calcium carbonate.
5. Process according to any one of Claims 1 to 4, characterised in that the organic binder is chosen from natural or chemically, enzymatically or thermally modified starches, dextrins, polyvinyl alcohols, casein, animal glue, vegetale proteins, cellulose esters, alginates and ready-for-use dispersion of synthetic polymers such as latices.
6. Process according to Claim 5, characterised in that the organic binder is natural starch employed after cooking.
7. Process according to Claim 5 or 6, characterised in that the quantity of binder is between 1 and 40 parts by weight and preferably between 1 and 25 parts by weight per 100 parts by weight of fibres and filler.
8. Process according to any one of Claims 1 to 7, characterised in that the cationicflocculant is incorporated in a quantity of between 0.006 and 5 parts by weight, and preferably between 0.01 and 2 parts by weight, per 100 parts by weight of inorganic filler and organic binder.
9. Process according to Claim 2, characterised in that the retention agent of an anionic nature is chosen from modified polyacrylamides of high molecular weight and sodium polyacrylates.
10. Process according to any one of Claims 1 to 9, characterised in that adjuvants which are usual in papermaking are additionally employed, such as a sizing agent, a pH regulating agent, an antifoam agent, an optical whitener, a colouring or tinting agent, a wetstrer.gth agent, a fungicidal and/or bactericidal agent, a dispersing agent, a lubricating agent and a viscosity regulator.
11. Process according to Claim 1, characterised in that the aqueous dispersion of inorganic filler particles coated with binder from stage 2) is a coating bath.
EP81108353A 1980-10-21 1981-10-15 Process for preparing a sheet material with retention by paper-making techniques Expired - Lifetime EP0050316B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81108353T ATE14765T1 (en) 1980-10-21 1981-10-15 PROCESS FOR MAKING A WEB MATERIAL WITH IMPROVED RETENTION ON A PAPER MACHINE.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8022501A FR2492425A1 (en) 1980-10-21 1980-10-21 PROCESS FOR THE PREPARATION BY PAPER TECHNIQUES OF A SHEET MATERIAL WITH IMPROVED MACHINE RETENTION, SHEET MATERIAL OBTAINED AND ITS APPLICATION IN PARTICULAR IN THE FIELD OF PRINTING WRITING, PACKAGING AND COATINGS
FR8022501 1980-10-21

Publications (3)

Publication Number Publication Date
EP0050316A1 EP0050316A1 (en) 1982-04-28
EP0050316B1 EP0050316B1 (en) 1985-08-07
EP0050316B2 true EP0050316B2 (en) 1991-12-04

Family

ID=9247151

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81108353A Expired - Lifetime EP0050316B2 (en) 1980-10-21 1981-10-15 Process for preparing a sheet material with retention by paper-making techniques

Country Status (7)

Country Link
US (1) US4943349A (en)
EP (1) EP0050316B2 (en)
AT (1) ATE14765T1 (en)
DE (2) DE3171717D1 (en)
ES (1) ES8302822A1 (en)
FI (1) FI69669C (en)
FR (1) FR2492425A1 (en)

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Also Published As

Publication number Publication date
ES506382A0 (en) 1983-01-16
DE50316T1 (en) 1983-04-14
EP0050316A1 (en) 1982-04-28
FI813268L (en) 1982-04-22
FI69669B (en) 1985-11-29
FR2492425A1 (en) 1982-04-23
ES8302822A1 (en) 1983-01-16
ATE14765T1 (en) 1985-08-15
DE3171717D1 (en) 1985-09-12
US4943349A (en) 1990-07-24
EP0050316B1 (en) 1985-08-07
FR2492425B1 (en) 1984-08-17
FI69669C (en) 1986-03-10

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