EP4183919A1 - Cellulose sheet packaging material with transparency obtained by coating - Google Patents

Cellulose sheet packaging material with transparency obtained by coating Download PDF

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Publication number
EP4183919A1
EP4183919A1 EP22208341.2A EP22208341A EP4183919A1 EP 4183919 A1 EP4183919 A1 EP 4183919A1 EP 22208341 A EP22208341 A EP 22208341A EP 4183919 A1 EP4183919 A1 EP 4183919A1
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EP
European Patent Office
Prior art keywords
layer
coating
cellulose
packaging material
coating layer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22208341.2A
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German (de)
French (fr)
Inventor
Ramiz AGPINAR
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Intersac
Original Assignee
Intersac
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Publication date
Application filed by Intersac filed Critical Intersac
Publication of EP4183919A1 publication Critical patent/EP4183919A1/en
Pending legal-status Critical Current

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Classifications

    • 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
    • D21H27/10—Packing paper
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D33/00—Details of, or accessories for, sacks or bags
    • B65D33/04—Windows or other apertures, e.g. for viewing contents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D5/00—Rigid or semi-rigid containers of polygonal cross-section, e.g. boxes, cartons or trays, formed by folding or erecting one or more blanks made of paper
    • B65D5/42—Details of containers or of foldable or erectable container blanks
    • B65D5/4204—Inspection openings or windows
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D65/00—Wrappers or flexible covers; Packaging materials of special type or form
    • B65D65/38—Packaging materials of special type or form
    • B65D65/42—Applications of coated or impregnated materials
    • 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
    • D21H19/00—Coated paper; Coating material
    • D21H19/72—Coated paper characterised by the paper substrate
    • 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

Definitions

  • the present invention relates to the manufacture and use of sheet materials having a certain at least partially localized transparency, more particularly intended for the field of packaging, and even more specifically for the packaging of food products.
  • the paper which relates to the invention is mainly made of cellulose, the transparency then being obtained by coating.
  • the invention also relates to a corresponding coating process, a device for coating strips of paper with a view to the constitution of the materials according to the invention, as well as packaging made of said material.
  • the invention responds to a growing need expressed by the food industry, mainly mass distribution, to provide visibility to bagged food products.
  • the idea is of course that the consumer can have informative visual access to what he is buying.
  • customers as much as manufacturers want food packaging that is respectful of the environment.
  • the objective of the invention is to create a packaging material entirely in paper, therefore mono-material, with the possibility of a transparent zone on at least a fraction of the surface of the packaging.
  • Such a product therefore responds to new demands due to the renewable nature of cellulose allowing complete recyclability of the packaging.
  • it is a question of creating a cellulose-based material which is able to present total or partial transparency, over at least part of the packaging.
  • the uniqueness of the material gives the packaging an enormous added value in practice, especially but not exclusively in the food sector.
  • the coating of paper to obtain a more or less successful transparency is already known, for example described in the document CN112853816A which discloses the manufacture of a transparent paper used to manufacture food packaging bags, or to make windows to be placed on food packaging boxes, from kraft paper coated with a preferably edible oil.
  • CN203753586U discloses a crystal paper bag with a window formed by making locally transparent an area of a sheet of paper from which said bag is made. Note that the base material of the bag is already translucent, and the more transparent window is achieved by applying a coating of wax to the glassine.
  • JP19890130188 describes the coating on a specific area of an opaque or translucent base paper with an oily solvent such as paraffin or with a silicone-based solution, so as to transform this area into a transparent surface.
  • FR628956A discloses a process for manufacturing transparent papers intended in particular for the packaging of food products, process according to which the paper to be made transparent is coated with a solution of gelatin or the like. The process consists more precisely in coating the paper with a gelatin solution which, after drying, then becomes transparent. Depending on the degree of transparency required, the gelatinous solution can be applied to one or both sides of the paper.
  • glassine type paper or glassine paper for the same objectives also results from the description of GB323302 , the paper then being impregnated with a solution of castor oil or the like and a methylated spirit type solvent containing an aromatic hydrocarbon such as benzol.
  • the document FR 3 008 392 does disclose a paper consisting of a coated cellulose layer, but this invention is more particularly focused on the coating, in this case the weight of the induction layer and the fact that it comprises a vegetable oil, the characteristics put forward for the cellulose layer being limited to the proportions of long and short fibres.
  • the most important part of the sheet materials rendered transparent in the field of the invention obviously remains the layer of paper, which is the main substrate secondarily supporting the coating layer.
  • a light weight paper is certainly less strong than a heavy weight paper, but it is also less opaque.
  • the choice of grammage, with a view to the aforementioned compromise, is therefore important.
  • papers with long fibers are certainly stronger than papers with short fibers, but the ratio between long and short fibers has an impact on the opacity of the paper, and it is therefore not conceivable to do without short fibres, at the risk of sacrificing transparency in favor of solidity.
  • Machine direction and cross machine direction practically refer to the continuous web manufacture of the paper, the web then being wound into reels for storage purposes.
  • the running direction is the unwinding direction of the reel ('long grain' in English), that is to say the axial direction of the strip.
  • the cross direction refers to a perpendicular, rather transverse direction.
  • the cellulose layer should preferably have a cloudy appearance, the corresponding structure of the paper proving to be particularly suitable for obtaining transparency where the coating layer is applied.
  • the par denotes an aspect of the structure of the paper observable by transparency, well known to those skilled in the art.
  • the pair can thus be qualified as regular or melted, irregular or cloudy, according to the more or less homogeneous distribution of the fibers: the qualifier attributed to the pair is immediately recognizable for the person skilled in the art who examines it. It is cloudy when the distribution is irregular and fluffy.
  • a cloudy patch means that the internal appearance of the cellulose layer is cloudy when it is observed by transparency in front of a light source.
  • the coating layer comprises vegetable wax, or animal wax or fat, or mineral paraffin, or a mixture of at least two of them.
  • the coating is used to improve the preservation characteristics of the packaging, its essential function - within the scope of the invention - of providing transparency on all or part of said packaging .
  • the coating layer has a weight of between 1 g/m 2 and 10 g/m 2 , more preferably still of between 4 g/m 2 and 8 g/m 2 .
  • the invention also relates to a process for manufacturing sheet packaging material as presented above, that is to say consisting essentially of a layer of cellulose coated with a coating layer, the process being such that the temperature for depositing said coating layer on the cellulose layer is between 50°C and 200°C or, preferably, between 60°C and 180°C.
  • the deposition temperature depends on the nature of the coating material (wax, paraffin, grease or oil). It may vary in order to guarantee good transparency and usability of the packaging at room temperature, or even at a temperature slightly higher than normal.
  • the cellulose layer covered with the coating layer is cooled at least once between 0° C. and 10° C., preferably between 2° C. and 6°C. This cooling is carried out by means of a cooling system comprising one or more successive cooling stages, making it possible to perpetuate the bond between the coating layer and the cellulose base layer.
  • a paper web printing stage can be arranged upstream of the coating rollers.
  • the coating of the cellulose is in fact generally carried out after the printing, total or partial, of the layer of cellulose.
  • the invention also relates to bag-type packaging made of packaging material according to the characteristics described above, which comprise at least one portion covered with a coating layer forming a transparent zone.
  • the manufacture of bags can then be carried out in various forms, for example by gluing a section of the packaging material as described, that is to say in fact at least one layer of cellulose coated with the coating layer of the invention on another side of the material, coated or not, so as to form a bag, said bag naturally comprising at least one opening.
  • the packaging concerned may be a box with a cardboard frame comprising at least one wall made of sheet packaging material according to the characteristics described above, which is then such that said at least one wall comprises at least one portion covered with a coating layer forming a transparent zone.
  • the invention as described has the preponderant advantage of allowing manufacture by dispensing with supply channels for transparent paper, which leads to a significant drop in production costs.
  • the technical characteristics of the two layers forming the packaging material are moreover such that the degree of transparency achieved can exceed 60%, reach 80%, or even 90% for certain combinations of characteristics.
  • only a portion of the packaging is made transparent, that is to say that the coating of the coating layer is applied by precisely delimiting it, so as to create a window in a bag or in a packaging which otherwise remains opaque.
  • the invention as a whole eliminates the need to separate a polymer window from the cellulose fiber part for recycling. and/or the composting of bags and packaging, which greatly facilitates these operations.
  • FIG. 1 represents a schematic view of a production line for a paper packaging material comprising a layer of cellulose which is coated with an additional layer as defined above, giving it at least localized transparency allowing consumers to see the packaged product;
  • FIG. 2 shows a schematic view of a bag according to the invention, one of the faces of which is provided with a transparent window obtained according to the invention.
  • the device appearing in figure 1 comprises successive rollers which guide and drive the strip of cellulose 1 towards a tray 2 containing a coating product 3 brought to a sufficient temperature for it to be in liquid form.
  • This coating temperature varies according to the nature of the coating product, which may be of plant, animal or mineral origin and, more particularly, may consist of wax, paraffin, grease, oil, etc. As indicated by the cartridge present in tray 2, said temperature can vary between 50°C and 200°C. It is ideally between 60°C and 180°C, in order to guarantee good transparency of the two-layer material, and consequently good usability of the bags, boxes, or other packaging at room temperature or a little higher.
  • two rollers 4, 5 ensure both the laying of the coating liquid on one side of the continuous strip of cellulose 1 - since only the roller 4 dips in said coating liquid - and the guiding of said strip 1 .
  • This system is in this case composed of two cooling rollers 6, 7 brought to a temperature between 0 and 10°C (see in particular the cartridges on said rollers 6, 7) and, more particularly, at a temperature of between 2 and 6°C.
  • Entry rollers 10, 11 and exit rollers 20, 21 complete the device, and make it possible to respectively guide the cellulose strip 1 towards the tray 2 at the entrance, and the bilayer strip towards the exit and possibly other stations.
  • processing for example a station for cutting sections of paper adapted to the type of packaging to be manufactured, and/or a gluing station. It should be noted that if a printed decoration must be applied to the paper, and/or a printing of information, it is done upstream of the coating rollers 4, 5, at the level or upstream of the entry rollers 10, 11.
  • the bag 30 of the figure 2 takes the form of an expandable flattenable pouch due to the existence of lateral bellows 31, 32 and a bottom 33 of substantially the same width, folding against one of the two sides main 34, 35 forming said bag 30.
  • One of these two sections 34, 35 comprises a window 36 obtained by coating with a layer of wax or varnish according to the invention.
  • the present invention makes it possible to make visible by transparency all or part of the contents of a packaging made of a material based on 100% cellulose, such as for example a bag, or which comprises a part with such a material, or a box whose a section is made up of it.
  • a packaging made of a material based on 100% cellulose, such as for example a bag, or which comprises a part with such a material, or a box whose a section is made up of it.
  • a packaging made of a material based on 100% cellulose, such as for example a bag, or which comprises a part with such a material, or a box whose a section is made up of it.
  • a visibility approaching plastic packaging that is to say which has a degree of opacity less than 40%, which can be lowered to 20%, knowing that it is even possible to reach 10%, which moreover constitutes the preferential objective.
  • polymers are totally eliminated, which makes them easily recyclable or compostable.
  • This type of packaging leads to a reduction

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Wrappers (AREA)
  • Laminated Bodies (AREA)

Abstract

Matériau d'emballage en feuille comportant une couche de cellulose recouverte d'une couche d'enduction revêtant ladite couche de cellulose pour la rendre transparente, la couche de cellulose présentant un grammage compris entre 18 g/m2 et 75 g/m2, contenant entre 10% et 60% de fibres courtes, présentant une résistance à la déchirure en sens travers d'au moins 138 mN, présentant une résistance à la déchirure en sens marche d'au moins 129 mN. La couche d'enduction comporte de la cire végétale, ou de la cire ou de la graisse animale, ou de la paraffine minérale, ou un mélange d'au moins deux d'entre eux.Procédé et dispositif d'enduction d'une bande de papier à couche de cellulose pour former le matériau d'emballage. Sac et boîte d'emballage comportant un tel matériau.Sheet packaging material comprising a layer of cellulose covered with a coating layer coating said layer of cellulose to make it transparent, the layer of cellulose having a basis weight of between 18 g/m2 and 75 g/m2, containing between 10% and 60% staple fibres, having a cross-direction tear strength of at least 138 mN, having a forward-direction tear strength of at least 129 mN. The coating layer comprises vegetable wax, or animal wax or fat, or mineral paraffin, or a mixture of at least two of them.Method and device for coating a strip of cellulose-coated paper to form the packaging material. Bag and packaging box comprising such a material.

Description

La présente invention a trait à la fabrication et à l'utilisation de matériaux en feuille présentant une certaine transparence au moins partiellement localisée, plus particulièrement destinés au domaine de l'emballage, et plus spécifiquement encore à l'emballage de produits alimentaires. Le papier qui relève de l'invention est principalement constitué de cellulose, la transparence étant ensuite obtenue par enduction. L'invention concerne aussi un procédé d'enduction correspondant, un dispositif pour l'enduction de bandes de papier en vue de la constitution des matériaux selon l'invention, ainsi que des emballages réalisés en ledit matériau.The present invention relates to the manufacture and use of sheet materials having a certain at least partially localized transparency, more particularly intended for the field of packaging, and even more specifically for the packaging of food products. The paper which relates to the invention is mainly made of cellulose, the transparency then being obtained by coating. The invention also relates to a corresponding coating process, a device for coating strips of paper with a view to the constitution of the materials according to the invention, as well as packaging made of said material.

L'invention répond à un besoin grandissant exprimé par la filière alimentaire, principalement la grande distribution, de procurer une visibilité aux produits alimentaires ensachés. L'idée est bien entendu que le consommateur puisse avoir un accès visuel informatif à ce qu'il achète. De plus, avec la prise de conscience des enjeux environnementaux, les clients autant que les fabricants veulent des emballages alimentaires qui soient respectueux de l'environnement.The invention responds to a growing need expressed by the food industry, mainly mass distribution, to provide visibility to bagged food products. The idea is of course that the consumer can have informative visual access to what he is buying. Moreover, with the awareness of environmental issues, customers as much as manufacturers want food packaging that is respectful of the environment.

Or, l'offre actuelle en emballages ensachés laissant le produit au moins partiellement visible propose soit des sacs en plastique, soit des emballages en cellulose avec une fenêtre en plastique. Cependant, dans la logique environnementale de réduction de la part du plastique dans les emballages préconisée de nos jours, la tendance est à remplacer les fenêtres en plastique fossile par des fenêtres en bio-plastique ou réalisées en des matériaux de type glassine, encore connu sous la dénomination de papier cristal.However, the current supply of bagged packaging leaving the product at least partially visible offers either plastic bags or cellulose packaging with a plastic window. However, in the environmental logic of reducing the share of plastic in packaging recommended today, the trend is to replace fossil plastic windows with bio-plastic windows or windows made of glassine type materials, still known as the denomination of crystal paper.

Toutefois, l'emploi de ces matériaux s'avère coûteux, du fait de la valeur économique du matériau proprement dit, qui est deux à trois fois plus cher à l'achat que le papier simple, mais également à cause des dépenses liées à la fabrication des emballages, qui nécessite de les associer aux papiers classiques dans les process de fabrication. La nécessité de mettre en place des filières d'approvisionnement distinctes contribue par ailleurs au prix plus élevé des emballages.However, the use of these materials is costly, due to the economic value of the material itself, which is two to three times more expensive to purchase than plain paper, but also because of the expenses associated with manufacture of packaging, which requires combining them with conventional papers in the manufacturing process. The need to set up separate supply chains also contributes to the higher price of packaging.

L'objectif de l'invention est de créer un matériau d'emballage intégralement en papier, par conséquent mono-matériau, avec la possibilité d'une zone transparente sur au moins une fraction de la surface de l'emballage. Un tel produit répond dès lors aux nouvelles demandes du fait du caractère renouvelable de la cellulose permettant une recyclabilité complète de l'emballage. En d'autres termes, il s'agit de créer un matériau à base de cellulose qui est apte à présenter une transparence totale ou partielle, sur au moins une partie de l'emballage. L'unicité de matériau confère en pratique aux emballages une énorme valeur ajoutée, notamment mais non exclusivement dans le secteur alimentaire.The objective of the invention is to create a packaging material entirely in paper, therefore mono-material, with the possibility of a transparent zone on at least a fraction of the surface of the packaging. Such a product therefore responds to new demands due to the renewable nature of cellulose allowing complete recyclability of the packaging. In other words, it is a question of creating a cellulose-based material which is able to present total or partial transparency, over at least part of the packaging. The uniqueness of the material gives the packaging an enormous added value in practice, especially but not exclusively in the food sector.

Il est à noter que l'enduction de papier pour obtenir une transparence plus ou moins aboutie est déjà connue, par exemple décrite dans le document CN112853816A qui divulgue la fabrication d'un papier transparent utilisé pour fabriquer des sacs d'emballage alimentaire, ou encore pour réaliser des fenêtres à disposer sur des boîtes d'emballages alimentaires, à partir de papier kraft enduit d'une huile de préférence comestible. CN203753586U divulgue quant à lui un sac en papier cristal avec une fenêtre formée en rendant localement transparente une zone d'une feuille de papier à partir de laquelle ledit sac est réalisé. Il est à noter que le matériau de base du sac est déjà translucide, et que la fenêtre plus transparente est obtenue en appliquant un revêtement de cire sur le papier cristal.It should be noted that the coating of paper to obtain a more or less successful transparency is already known, for example described in the document CN112853816A which discloses the manufacture of a transparent paper used to manufacture food packaging bags, or to make windows to be placed on food packaging boxes, from kraft paper coated with a preferably edible oil. CN203753586U discloses a crystal paper bag with a window formed by making locally transparent an area of a sheet of paper from which said bag is made. Note that the base material of the bag is already translucent, and the more transparent window is achieved by applying a coating of wax to the glassine.

JP19890130188 décrit l'enduction sur une zone spécifique d'un papier de base opaque ou translucide avec un solvant huileux de type paraffine ou avec une solution à base de silicone, de manière à transformer cette zone en une surface transparente. FR628956A divulgue un procédé de fabrication de papiers transparents destinés notamment à l'emballage de produits alimentaires, procédé selon lequel le papier à rendre transparent est enduit d'une solution de gélatine ou analogue. Le procédé consiste plus précisément à enduire d'une solution de gélatine le papier qui, après séchage, devient alors transparent. Selon le degré de transparence requis, la solution gélatineuse peut être appliquée sur l'une ou sur les deux faces du papier. L'utilisation de papier de type glassine ou papier cristal pour les mêmes objectifs résulte par ailleurs de la description de GB323302 , le papier étant alors imprégné d'une solution d'huile de ricin ou analogue et d'un solvant de type alcool à brûler contenant un hydrocarbure aromatique tel que du benzol. JP19890130188 describes the coating on a specific area of an opaque or translucent base paper with an oily solvent such as paraffin or with a silicone-based solution, so as to transform this area into a transparent surface. FR628956A discloses a process for manufacturing transparent papers intended in particular for the packaging of food products, process according to which the paper to be made transparent is coated with a solution of gelatin or the like. The process consists more precisely in coating the paper with a gelatin solution which, after drying, then becomes transparent. Depending on the degree of transparency required, the gelatinous solution can be applied to one or both sides of the paper. The use of glassine type paper or glassine paper for the same objectives also results from the description of GB323302 , the paper then being impregnated with a solution of castor oil or the like and a methylated spirit type solvent containing an aromatic hydrocarbon such as benzol.

Le principe de l'imprégnation ou de l'enduction de papier pour le rendre transparent est donc connu de longue date, car la plupart de ces documents sont anciens. Pour autant, dans certains cas ci-dessus, le papier utilisé est de la glassine ou du papier cristal, dont le coût propre d'une part et la nécessité de l'associer avec d'autres types de papiers pour la fabrication de l'emballage final d'autre part constituent des obstacles rédhibitoires au sens de l'invention.The principle of impregnating or coating paper to make it transparent has therefore been known for a long time, since most of these documents are old. However, in some of the cases above, the paper used is glassine or crystal paper, the cost of which on the one hand and the need to combine it with other types of paper for the manufacture of the final packaging on the other hand constitute prohibitive obstacles within the meaning of the invention.

Le document FR 3 008 392 divulgue bien un papier constituée d'une couche de cellulose enduite, mais cette invention est plus particulièrement focalisée sur l'enduction, en l'espèce le poids de la couche d'induction et le fait qu'elle comprenne une huile végétale, les caractéristiques mises en avant pour la couche de cellulose étant limitées aux proportions de fibres longues et courtes. Or, la partie la plus importante des matériaux en feuille rendus transparents du domaine de l'invention reste évidemment la couche de papier, qui est le substrat principal supportant secondairement la couche d'enduction.The document FR 3 008 392 does disclose a paper consisting of a coated cellulose layer, but this invention is more particularly focused on the coating, in this case the weight of the induction layer and the fact that it comprises a vegetable oil, the characteristics put forward for the cellulose layer being limited to the proportions of long and short fibres. However, the most important part of the sheet materials rendered transparent in the field of the invention obviously remains the layer of paper, which is the main substrate secondarily supporting the coating layer.

Or, pour pouvoir présenter un bon compromis transparence/solidité, indispensable pour les multiples applications actuelles, les papiers adéquats doivent être sélectionnés de manière à présenter des propriétés techniques, notamment mécaniques, adaptées. Avant tout travail sur l'enduit, il faut donc proposer un papier qui présente une combinaison de caractéristiques techniques le rendant certes apte à être enduit, mais surtout présentant un compromis solidité/transparence/souplesse adéquat.However, in order to be able to present a good transparency/solidity compromise, which is essential for the many current applications, the appropriate papers must be selected so as to present suitable technical properties, in particular mechanical properties. Before any work on the coating, it is therefore necessary to propose a paper which has a combination of technical characteristics making it certainly suitable for being coated, but above all presenting an adequate strength/transparency/flexibility compromise.

C'est l'objectif de la présente invention, qui se propose notamment de combiner optimalement les caractéristiques techniques des éléments entrant dans la composition des matériaux d'emballage, de sorte qu'ils présentent d'une part une solidité compatible avec leur utilisation en tant qu'emballage par exemple de produits alimentaires et d'autre part qu'on puisse leur conférer un degré de transparence suffisant pour que les produits emballés soient bien visibles.This is the objective of the present invention, which proposes in particular to combine optimally the technical characteristics of the elements entering into the composition of the packaging materials, so that they present on the one hand a solidity compatible with their use in as packaging for example of food products and on the other hand that they can be given a degree of transparency sufficient for the packaged products to be clearly visible.

A cet effet, l'invention concerne d'abord un matériau d'emballage en feuille comportant une couche de cellulose recouverte d'une couche d'enduction revêtant ladite couche de cellulose pour la rendre transparente, caractérisé en ce que la couche de cellulose :

  • présente un grammage compris entre 18 g/m2 et 75 g/m2 ;
  • contient entre 10% et 60% de fibres courtes ;
  • présente une résistance à la déchirure en sens travers comprise entre 138 mN et 250 mN ; et
  • présente une résistance à la déchirure en sens marche comprise entre 129 mN et 220 mN.
To this end, the invention firstly relates to a packaging material in sheet form comprising a layer of cellulose covered with a coating layer coating said layer of cellulose to make it transparent, characterized in that the layer of cellulose:
  • has a basis weight of between 18 g/m 2 and 75 g/m 2 ;
  • contains between 10% and 60% short fibres;
  • has a tear strength in the transverse direction of between 138 mN and 250 mN; And
  • has a tear resistance in the forward direction of between 129 mN and 220 mN.

En termes de solidité, un papier à faible grammage est certes moins solide qu'un papier à fort grammage, mais il est également moins opaque. Le choix du grammage, dans l'optique du compromis précité, est donc important. De même, les papiers ayant des fibres longues sont certainement plus solides que les papiers ayant des fibres courtes, mais le ratio entre les fibres longues et courtes a un impact sur l'opacité du papier, et il n'est dès lors pas concevable de se passer de fibres courtes, au risque de sacrifier la transparence au profit de la solidité.In terms of strength, a light weight paper is certainly less strong than a heavy weight paper, but it is also less opaque. The choice of grammage, with a view to the aforementioned compromise, is therefore important. Similarly, papers with long fibers are certainly stronger than papers with short fibers, but the ratio between long and short fibers has an impact on the opacity of the paper, and it is therefore not conceivable to do without short fibres, at the risk of sacrificing transparency in favor of solidity.

Pour trouver le papier le plus apte à devenir transparent grâce à l'enduction sans pour autant négliger son aptitude à transporter des denrées, alimentaires ou non, il importe de considérer également certaines propriétés mécaniques du papier comme sa résistance aux déchirures dans le sens marche et dans le sens travers, voire sa résistance à l'éclatement ou encore sa résistance à l'allongement dans le sens marche et dans le sens travers. Sens marche et sens travers font en pratique référence à la fabrication en bande continue du papier, la bande étant ensuite enroulée en bobines à des fins de stockage. Dans cette perspective, le sens marche est le sens de déroulage de la bobine ('long grain' en anglais), c'est-à-dire le sens axial de la bande. Le sens travers fait référence à une direction perpendiculaire, plutôt transversale.To find the paper best suited to becoming transparent thanks to the coating without neglecting its ability to transport foodstuffs, food or not, it is also important to consider certain mechanical properties of the paper such as its resistance to tearing in the direction of travel and in the cross direction, even its resistance to bursting or its resistance to elongation in the direction of travel and in the cross direction. Machine direction and cross machine direction practically refer to the continuous web manufacture of the paper, the web then being wound into reels for storage purposes. In this perspective, the running direction is the unwinding direction of the reel ('long grain' in English), that is to say the axial direction of the strip. The cross direction refers to a perpendicular, rather transverse direction.

Par ailleurs, de préférence, la couche de cellulose doit présenter un épair nuageux, la structure correspondante du papier s'avérant particulièrement appropriée pour l'obtention de la transparence là où est appliquée la couche d'enduction. L'épair désigne un aspect de la structure du papier observable par transparence, bien connu des personnes de l'art. L'épair peut ainsi être qualifié de régulier ou fondu, d'irrégulier ou de nuageux, selon la répartition plus ou moins homogène des fibres : le qualificatif qu'on attribue à l'épair est immédiatement reconnaissable pour la personne de l'art qui l'examine. Il est nuageux quand la répartition est irrégulière et floconneuse. En d'autres termes encore, un épair nuageux signifie que l'aspect interne de la couche de cellulose est nuageux lorsqu'on l'observe par transparence devant une source de lumière.Furthermore, the cellulose layer should preferably have a cloudy appearance, the corresponding structure of the paper proving to be particularly suitable for obtaining transparency where the coating layer is applied. The par denotes an aspect of the structure of the paper observable by transparency, well known to those skilled in the art. The pair can thus be qualified as regular or melted, irregular or cloudy, according to the more or less homogeneous distribution of the fibers: the qualifier attributed to the pair is immediately recognizable for the person skilled in the art who examines it. It is cloudy when the distribution is irregular and fluffy. In other words again, a cloudy patch means that the internal appearance of the cellulose layer is cloudy when it is observed by transparency in front of a light source.

Selon l'invention, la couche d'enduction comporte de la cire végétale, ou de la cire ou de la graisse animale, ou de la paraffine minérale, ou un mélange d'au moins deux d'entre eux. Contrairement à nombre de configurations connues, où l'enduction est utilisée pour améliorer les caractéristiques de conservation de l'emballage, elle a pour fonction essentielle - dans le cadre de l'invention - d'apporter de la transparence sur tout ou partie dudit emballage.According to the invention, the coating layer comprises vegetable wax, or animal wax or fat, or mineral paraffin, or a mixture of at least two of them. Unlike many known configurations, where the coating is used to improve the preservation characteristics of the packaging, its essential function - within the scope of the invention - of providing transparency on all or part of said packaging .

De préférence, la couche d'enduction présente un poids compris entre 1 g/m2 et 10 g/m2, de préférence encore compris entre 4 g/m2 et 8 g/m2.Preferably, the coating layer has a weight of between 1 g/m 2 and 10 g/m 2 , more preferably still of between 4 g/m 2 and 8 g/m 2 .

L'invention concerne, également un procédé de fabrication de matériau d'emballage en feuille tel que présenté ci-dessus, c'est-à-dire essentiellement constitué d'une couche de cellulose revêtue d'une couche d'enduction, le procédé étant tel que la température de dépose de ladite couche d'enduction sur la couche de cellulose est comprise entre 50°C et 200°C ou, de préférence, entre 60°C et 180°C.The invention also relates to a process for manufacturing sheet packaging material as presented above, that is to say consisting essentially of a layer of cellulose coated with a coating layer, the process being such that the temperature for depositing said coating layer on the cellulose layer is between 50°C and 200°C or, preferably, between 60°C and 180°C.

En réalité, la température de dépose dépend de la nature du matériau d'enduction (cire, paraffine, graisse ou huile). Elle peut varier afin de garantir la bonne transparence et l'utilisabilité des emballages à température ambiante, voire à une température un peu supérieure aux normales.In reality, the deposition temperature depends on the nature of the coating material (wax, paraffin, grease or oil). It may vary in order to guarantee good transparency and usability of the packaging at room temperature, or even at a temperature slightly higher than normal.

Afin de figer la couche d'enduction, selon le procédé de l'invention, la couche de cellulose recouverte de la couche d'enduit est refroidie au moins une fois entre 0°C et 10°C, de préférence entre 2°C et 6°C. Ce refroidissement est effectué au moyen d'un système de refroidissement comportant un ou plusieurs étages successifs de refroidissement, permettant de pérenniser la liaison entre la couche d'enduction et la couche de base de cellulose.In order to set the coating layer, according to the method of the invention, the cellulose layer covered with the coating layer is cooled at least once between 0° C. and 10° C., preferably between 2° C. and 6°C. This cooling is carried out by means of a cooling system comprising one or more successive cooling stages, making it possible to perpetuate the bond between the coating layer and the cellulose base layer.

Un dispositif est également prévu, selon l'invention, pour l'enduction d'une bande continue de papier constituée d'une couche de cellulose, caractérisé en ce qu'il comporte :

  • Au moins deux rouleaux d'enduction entre lesquels la bande est entraînée, au moins un desdits rouleaux d'enduction étant au moins partiellement plongé dans un bac de cire végétale, ou de cire ou graisse animale, ou de paraffine minérale, ou d'un mélange d'au moins deux d'entre eux, porté à une température comprise entre 50°C et 200°C ;
  • au moins un rouleau de refroidissement placé en aval des rouleaux d'enduction, dans le sens de défilement de la bande, ledit rouleau étant porté à une température comprise entre 0°C et 10°C.
A device is also provided, according to the invention, for coating a continuous web of paper consisting of a layer of cellulose, characterized in that it comprises:
  • At least two coating rollers between which the strip is driven, at least one of said coating rollers being at least partially immersed in a tray of vegetable wax, or animal wax or fat, or mineral paraffin, or a mixture of at least two of them, brought to a temperature of between 50° C. and 200° C.;
  • at least one cooling roller placed downstream of the coating rollers, in the running direction of the strip, said roller being brought to a temperature of between 0°C and 10°C.

Selon une configuration possible, un étage d'impression de la bande de papier peut être disposé en amont des rouleaux d'enduction. L'enduction de la cellulose est en effet généralement réalisée après l'impression, totale ou partielle, de la couche de cellulose.According to one possible configuration, a paper web printing stage can be arranged upstream of the coating rollers. The coating of the cellulose is in fact generally carried out after the printing, total or partial, of the layer of cellulose.

Enfin, l'invention concerne aussi des emballages de type sac en matériau d'emballage selon les caractéristiques décrites auparavant, qui comportent au moins une portion recouverte d'une couche d'enduction formant une zone transparente. La fabrication de sacs peut alors être réalisée sous différentes formes, par exemple en collant un pan du matériau d'emballage tel que décrit, c'est-à-dire en fait au moins une couche de cellulose enduite de la couche d'enduction de l'invention sur un autre pan du matériau, enduit ou non, de façon à former un sac, ledit sac comportant bien entendu au moins une ouverture.Finally, the invention also relates to bag-type packaging made of packaging material according to the characteristics described above, which comprise at least one portion covered with a coating layer forming a transparent zone. The manufacture of bags can then be carried out in various forms, for example by gluing a section of the packaging material as described, that is to say in fact at least one layer of cellulose coated with the coating layer of the invention on another side of the material, coated or not, so as to form a bag, said bag naturally comprising at least one opening.

Alternativement, mais non limitativement, l'emballage concerné peut être une boîte à ossature en carton comportant au moins une paroi en matériau d'emballage en feuille selon les caractéristiques décrites auparavant, qui est alors tel que ladite au moins une paroi comporte au moins une portion recouverte d'une couche d'enduction formant une zone transparente.Alternatively, but not limitatively, the packaging concerned may be a box with a cardboard frame comprising at least one wall made of sheet packaging material according to the characteristics described above, which is then such that said at least one wall comprises at least one portion covered with a coating layer forming a transparent zone.

L'invention telle qu'exposée présente l'avantage prépondérant de permettre une fabrication en s'affranchissant des filières d'approvisionnement en papier transparent, ce qui conduit à une baisse sensible des coûts de production. Les caractéristiques techniques des deux couches formant le matériau d'emballage sont par ailleurs telles que le degré de transparence atteint peut dépasser les 60%, atteindre 80%, voire 90% pour certaines combinaisons de caractéristiques. Dans la plupart des cas, seule une portion des emballages est rendue transparente, c'est-à-dire que l'enduction de la couche de revêtement est appliquée en la délimitant précisément, de sorte à créer une fenêtre dans un sac ou dans un emballage qui reste par ailleurs opaque.The invention as described has the preponderant advantage of allowing manufacture by dispensing with supply channels for transparent paper, which leads to a significant drop in production costs. The technical characteristics of the two layers forming the packaging material are moreover such that the degree of transparency achieved can exceed 60%, reach 80%, or even 90% for certain combinations of characteristics. In most cases, only a portion of the packaging is made transparent, that is to say that the coating of the coating layer is applied by precisely delimiting it, so as to create a window in a bag or in a packaging which otherwise remains opaque.

L'invention, dans son ensemble, permet de s'affranchir de la nécessité de séparer une fenêtre en polymère de la partie en fibre de cellulose pour le recyclage et/ou le compostage des sacs et emballages, ce qui facilite grandement ces opérations.The invention as a whole eliminates the need to separate a polymer window from the cellulose fiber part for recycling. and/or the composting of bags and packaging, which greatly facilitates these operations.

D'autres buts et avantages de la présente invention apparaîtront au cours de la description qui va suivre se rapportant à des modes de réalisation qui ne sont donnés qu'à titre d'exemples indicatifs et non limitatifs.Other aims and advantages of the present invention will appear during the description which will follow relating to embodiments which are given only by way of indicative and non-limiting examples.

La compréhension de cette description sera facilitée en se référant aux dessins joints en annexe, et pour lesquels :The understanding of this description will be facilitated by referring to the attached drawings, and for which:

La figure 1 représente une vue schématisée d'une ligne de fabrication d'un matériau d'emballage en papier comportant une couche de cellulose qui est enduite d'une couche additionnelle telle que définie auparavant, lui conférant une transparence au moins localisée permettant aux consommateurs de voir le produit emballé ;There figure 1 represents a schematic view of a production line for a paper packaging material comprising a layer of cellulose which is coated with an additional layer as defined above, giving it at least localized transparency allowing consumers to see the packaged product;

La figure 2 montre une vue schématisée d'un sac selon l'invention, dont l'une des faces est munie d'une fenêtre transparente obtenue selon l'invention.There picture 2 shows a schematic view of a bag according to the invention, one of the faces of which is provided with a transparent window obtained according to the invention.

Le dispositif apparaissant en figure 1 comporte des rouleaux successifs qui guident et entraînent la bande de cellulose 1 vers un bac 2 contenant un produit d'enduction 3 porté à une température suffisante pour qu'il soit sous forme liquide. Cette température d'enduction varie selon la nature du produit d'enduction, qui peut être d'origine végétale, animale ou minérale et, plus particulièrement, être constitué de cire, de paraffine, de graisse, d'huile etc. Comme l'indique le cartouche présent dans le bac 2, ladite température peut varier entre 50°C et 200°C. Elle se situe idéalement entre 60°C et 180°C, afin de garantir la bonne transparence du matériau bicouche, et par conséquent une bonne utilisabilité des sacs, boîtes, ou autres emballages à température ambiante ou un peu plus élevée.The device appearing in figure 1 comprises successive rollers which guide and drive the strip of cellulose 1 towards a tray 2 containing a coating product 3 brought to a sufficient temperature for it to be in liquid form. This coating temperature varies according to the nature of the coating product, which may be of plant, animal or mineral origin and, more particularly, may consist of wax, paraffin, grease, oil, etc. As indicated by the cartridge present in tray 2, said temperature can vary between 50°C and 200°C. It is ideally between 60°C and 180°C, in order to guarantee good transparency of the two-layer material, and consequently good usability of the bags, boxes, or other packaging at room temperature or a little higher.

En pratique, deux rouleaux 4, 5 assurent à la fois la pose du liquide d'enduction sur une face de la bande continue de cellulose 1 - puisque seul le rouleau 4 trempe dans ledit liquide d'enduction - et le guidage de ladite bande 1.In practice, two rollers 4, 5 ensure both the laying of the coating liquid on one side of the continuous strip of cellulose 1 - since only the roller 4 dips in said coating liquid - and the guiding of said strip 1 .

Afin de pérenniser l'enduction, c'est-à-dire de garantir que la couche d'enduction reste bien fixée sur la couche de cellulose, un système de refroidissement est nécessaire. Ce système est en l'espèce composé de deux rouleaux 6, 7 de refroidissement portés à une température comprise entre 0 et 10°C (voir en particulier les cartouches sur lesdits rouleaux 6, 7) et, plus particulièrement, à une température comprise entre 2 et 6°C.In order to perpetuate the coating, that is to say to guarantee that the coating layer remains firmly attached to the cellulose layer, a cooling system is necessary. This system is in this case composed of two cooling rollers 6, 7 brought to a temperature between 0 and 10°C (see in particular the cartridges on said rollers 6, 7) and, more particularly, at a temperature of between 2 and 6°C.

Des rouleaux d'entrée 10, 11 et des rouleaux de sortie 20, 21 complètent le dispositif, et permettent de guider respectivement la bande de cellulose 1 vers le bac 2 en entrée, et la bande bicouche vers la sortie et éventuellement d'autres postes de traitement, par exemple un poste de découpe de pans de papier adaptés au type d'emballage à fabriquer, et/ou un poste de collage. A noter que si une décoration imprimée doit être appliquée au papier, et/ou une impression d'informations, elle se fait en amont des rouleaux d'enduction 4, 5, au niveau ou en amont des rouleaux d'entrée 10, 11.Entry rollers 10, 11 and exit rollers 20, 21 complete the device, and make it possible to respectively guide the cellulose strip 1 towards the tray 2 at the entrance, and the bilayer strip towards the exit and possibly other stations. processing, for example a station for cutting sections of paper adapted to the type of packaging to be manufactured, and/or a gluing station. It should be noted that if a printed decoration must be applied to the paper, and/or a printing of information, it is done upstream of the coating rollers 4, 5, at the level or upstream of the entry rollers 10, 11.

Le sac 30 de la figure 2, obtenu selon les caractéristiques de l'invention, prend la forme d'une pochette aplatissable expansible du fait de l'existence de soufflets 31, 32 latéraux et d'un fond 33 sensiblement de même largeur, repliable contre l'un des deux pans principaux 34, 35 formant ledit sac 30. L'un de ces deux pans 34, 35 comporte une fenêtre 36 obtenue par enduction d'une couche de cire ou de vernis selon l'invention.The bag 30 of the figure 2 , obtained according to the characteristics of the invention, takes the form of an expandable flattenable pouch due to the existence of lateral bellows 31, 32 and a bottom 33 of substantially the same width, folding against one of the two sides main 34, 35 forming said bag 30. One of these two sections 34, 35 comprises a window 36 obtained by coating with a layer of wax or varnish according to the invention.

Il est à noter que les caractéristiques inhérentes à la présente invention n'altèrent pas les caractéristiques standards des emballages ou sacs prévus pour contenir des produits alimentaires, comme celui présenté en figure 2, à savoir :

  • test de résistance à l'éclatement : au moins 70 kPa ;
  • test de perméabilité : au moins 14s/100ml ;
  • résistance à l'humidité : de 0 à 50 % selon le cas.
It should be noted that the characteristics inherent in the present invention do not alter the standard characteristics of packaging or bags intended to contain food products, such as the one presented in picture 2 , to know :
  • burst strength test: at least 70 kPa;
  • permeability test: at least 14s/100ml;
  • humidity resistance: from 0 to 50% depending on the case.

In fine, la présente invention permet rendre visible par transparence tout ou partie du contenu d'un emballage en un matériau à base de 100% de cellulose comme par exemple un sac, ou qui comporte une partie avec un tel matériau, ou une boîte dont un pan en est constitué. En d'autres termes, elle permet de réaliser par exemple des sacs ou des boîtes dont une portion au moins présente une visibilité se rapprochant d'un emballage en plastique, c'est-à-dire qui présente un degré d'opacité inférieur à 40%, que l'on peut abaisser à 20%, sachant qu'il est même possible d'atteindre 10%, ce qui constitue d'ailleurs l'objectif préférentiel. Dans un tel emballage, les polymères sont totalement supprimés, ce qui les rend facilement recyclables ou compostables. Ce genre d'emballages conduit à diminuer les déchets d'emballage du fait de son caractère mono-matériau.Ultimately, the present invention makes it possible to make visible by transparency all or part of the contents of a packaging made of a material based on 100% cellulose, such as for example a bag, or which comprises a part with such a material, or a box whose a section is made up of it. In other words, it makes it possible, for example, to produce bags or boxes of which at least a portion has a visibility approaching plastic packaging, that is to say which has a degree of opacity less than 40%, which can be lowered to 20%, knowing that it is even possible to reach 10%, which moreover constitutes the preferential objective. In such packaging, polymers are totally eliminated, which makes them easily recyclable or compostable. This type of packaging leads to a reduction in packaging waste due to its mono-material nature.

L'invention décrite ne se limite pas aux exemples donnés, notamment en référence aux figures, mais elle englobe notamment les variations de forme apportées par exemple au sac de la figure 2.The invention described is not limited to the examples given, in particular with reference to the figures, but it encompasses in particular the variations in shape made, for example, to the bag of the picture 2 .

Claims (13)

Matériau d'emballage en feuille comportant une couche de cellulose recouverte d'une couche d'enduction revêtant ladite couche de cellulose pour la rendre transparente, caractérisé en ce que la couche de cellulose : - présente un grammage compris entre 18 g/m2 et 75 g/m2, - contient entre 10% et 60% de fibres courtes, - présente une résistance à la déchirure en sens travers comprise entre 138 mN et 250 mN, et - présente une résistance à la déchirure en sens marche comprise entre 129 mN et 220 mN. Sheet packaging material comprising a layer of cellulose covered with a coating layer coating said layer of cellulose to make it transparent, characterized in that the layer of cellulose: - has a weight between 18 g/m 2 and 75 g/m 2 , - contains between 10% and 60% short fibres, - has a tear resistance in the transverse direction of between 138 mN and 250 mN, and - has a tear resistance in the forward direction of between 129 mN and 220 mN. Matériau d'emballage en feuille comportant une couche de cellulose recouverte d'une couche d'enduction selon la revendication 1 caractérisé en ce que la couche de cellulose présente un épair nuageux.Sheet packaging material comprising a layer of cellulose covered with a coating layer according to Claim 1 , characterized in that the layer of cellulose has a cloudy appearance. Matériau d'emballage en feuille comportant une couche de cellulose recouverte d'une couche d'enduction selon l'une des revendications précédentes, caractérisé en ce que la couche d'enduction comporte de la cire végétale, ou de la cire ou de la graisse animale, ou de la paraffine minérale, ou un mélange d'au moins deux d'entre eux.Sheet packaging material comprising a layer of cellulose covered with a coating layer according to one of the preceding claims, characterized in that the coating layer comprises vegetable wax, or wax or fat animal, or mineral paraffin, or a mixture of at least two of them. Matériau d'emballage en feuille comportant une couche de cellulose recouverte d'une couche d'enduction selon la revendication précédente, caractérisé en ce que la couche d'enduction présente un poids compris entre 1 g/m2 et 10 g/m2.Sheet packaging material comprising a layer of cellulose covered with a coating layer according to the preceding claim, characterized in that the coating layer has a weight of between 1 g/m 2 and 10 g/m 2 . Matériau d'emballage en feuille comportant une couche de cellulose recouverte d'une couche d'enduction selon la revendication 3, caractérisé en ce que la couche d'enduction présente un poids compris entre 4 g/m2 et 8 g/m2.Sheet packaging material comprising a layer of cellulose covered with a coating layer according to claim 3, characterized in that the coating layer has a weight of between 4 g/m 2 and 8 g/m 2 . Procédé d'enduction de papier pour la fabrication de matériau d'emballage en feuille constitué d'une couche de cellulose revêtue d'une couche d'enduction selon les revendications précédentes, caractérisé en ce que la température de dépose de ladite couche d'enduction sur la couche de cellulose est comprise entre 50°C et 200°C.Process for coating paper for the manufacture of packaging material in sheet form consisting of a layer of cellulose coated with a coating layer according to the preceding claims, characterized in that the temperature of depositing said coating layer on the cellulose layer is between 50°C and 200°C. Procédé d'enduction de papier constitué d'une couche de cellulose revêtue d'une couche d'enduction selon la revendication précédente, caractérisé en ce que la température de dépose de la couche d'enduction sur la couche de cellulose est comprise entre 60°C et 180°C.Process for coating paper consisting of a layer of cellulose coated with a coating layer according to the preceding claim, characterized in that the temperature for depositing the coating layer on the cellulose layer is between 60° C and 180°C. Procédé d'enduction de papier pour la fabrication de matériau d'emballage en feuille constitué d'une couche de cellulose revêtue d'une couche d'enduction selon l'une des revendications 6 et 7, caractérisé en ce que la couche de cellulose recouverte de la couche d'enduction est refroidie au moins une fois entre 0°C et 10°C.Process for coating paper for the manufacture of sheet packaging material consisting of a layer of cellulose coated with a coating layer according to one of Claims 6 and 7, characterized in that the layer of cellulose covered of the coating layer is cooled at least once between 0°C and 10°C. Procédé d'enduction de papier pour la fabrication de matériau d'emballage en feuille constitué d'une couche de cellulose revêtue d'une couche d'enduction selon la revendication 8, caractérisé en ce que la couche de cellulose recouverte de la couche d'enduit est refroidie au moins une fois entre 2°C et 6°C.Process for coating paper for the manufacture of sheet packaging material consisting of a layer of cellulose coated with a coating layer according to claim 8, characterized in that the layer of cellulose covered with the layer of plaster is cooled at least once between 2°C and 6°C. Dispositif pour l'enduction d'une bande (1) continue de papier constituée d'une couche de cellulose, caractérisé en ce qu'il comporte : - au moins deux rouleaux d'enduction (4, 5) entre lesquels la bande (1) est entraînée, au moins un desdits rouleaux d'enduction (4, 5) étant au moins partiellement plongé dans un bac (2) de cire végétale, ou de cire ou graisse animale, ou de paraffine minérale, ou d'un mélange d'au moins deux d'entre eux, porté à une température comprise entre 50° C et 200° C ; - au moins un rouleau de refroidissement (6, 7) placé en aval des rouleaux d'enduction (4, 5), dans le sens de défilement de la bande (1), ledit rouleau (6, 7) étant porté à une température comprise entre 0°C et 10°C. Device for coating a continuous strip (1) of paper consisting of a layer of cellulose, characterized in that it comprises: - at least two coating rollers (4, 5) between which the strip (1) is driven, at least one of said coating rollers (4, 5) being at least partially immersed in a container (2) of vegetable wax , or wax or animal fat, or mineral paraffin, or a mixture of at least two of them, brought to a temperature between 50° C. and 200° C.; - at least one cooling roller (6, 7) placed downstream of the coating rollers (4, 5), in the running direction of the web (1), said roller (6, 7) being brought to a temperature between 0°C and 10°C. Dispositif pour l'enduction d'une bande (1) continue de papier constituée d'une couche de cellulose selon la revendication précédente, caractérisé en ce qu'un étage d'impression de la bande (1) de papier est disposé en amont des rouleaux d'enduction (4, 5).Device for coating a continuous strip (1) of paper consisting of a layer of cellulose according to the preceding claim, characterized in that a printing stage for the strip (1) of paper is arranged upstream of the coating rollers (4, 5). Emballage de type sac en matériau d'emballage en feuille selon l'une des revendications 1 à 5, caractérisé en ce qu'il comporte au moins une portion recouverte d'une couche d'enduction formant une zone transparente. 1Bag-type packaging made of sheet packaging material according to one of Claims 1 to 5, characterized in that it comprises at least one portion covered with a coating layer forming a transparent zone. 1 Boîte à ossature en carton comportant au moins une paroi en matériau d'emballage en feuille selon l'une des revendications 1 à 5, caractérisée en ce que ladite au moins une paroi comporte au moins une portion recouverte d'une couche d'enduction formant une zone transparente.Cardboard frame box having at least one wall made of sheet packaging material according to one of Claims 1 to 5, characterized in that said at least one wall comprises at least one portion covered with a coating layer forming a transparent zone.
EP22208341.2A 2021-11-23 2022-11-18 Cellulose sheet packaging material with transparency obtained by coating Pending EP4183919A1 (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR628956A (en) 1926-10-09 1927-11-02 Klotz Geb Process for manufacturing transparent papers intended in particular for the packaging of food products
GB323302A (en) 1928-10-30 1930-01-02 James Chamberlain Improvements in or relating to transparent sheet material
JPH0130188B2 (en) 1976-01-14 1989-06-16 Pitney Bowes
CN203753586U (en) 2013-10-18 2014-08-06 卢壮兴 Paper-bag improved structure capable of seeing through contents
FR3008392A1 (en) 2013-07-15 2015-01-16 Ace Packaging Nv BAG FOR PRESERVING BREAD.
CN112853816A (en) 2021-01-19 2021-05-28 厦门吉宏科技股份有限公司 Food-grade ultratransparent paper and production process, production equipment and application thereof

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR628956A (en) 1926-10-09 1927-11-02 Klotz Geb Process for manufacturing transparent papers intended in particular for the packaging of food products
GB323302A (en) 1928-10-30 1930-01-02 James Chamberlain Improvements in or relating to transparent sheet material
JPH0130188B2 (en) 1976-01-14 1989-06-16 Pitney Bowes
FR3008392A1 (en) 2013-07-15 2015-01-16 Ace Packaging Nv BAG FOR PRESERVING BREAD.
CN203753586U (en) 2013-10-18 2014-08-06 卢壮兴 Paper-bag improved structure capable of seeing through contents
CN112853816A (en) 2021-01-19 2021-05-28 厦门吉宏科技股份有限公司 Food-grade ultratransparent paper and production process, production equipment and application thereof

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