Wrapping sheet, packaging formed from such a wrapping sheet, and corresponding manufacturing process

Abstract

Packaging sheet, packaging formed from such a packaging sheet and corresponding manufacturing process The present invention relates to a packaging sheet (10) intended to form by folding a packaging (15) forming an internal volume delimited by a plurality of walls (Pi), the packaging sheet (15) comprising said walls (Pi) before folding as well as at least one closing flap (Ri) in the extension of a respective wall (Pi), an external contact surface (Sext_i) of the flap being intended to come into contact with an internal contact surface (Cint_k) of an internal face (Fint_k) of another wall (Pk) for the closure of the packaging (15).At least one of the external contact surface (Sext_i) and the internal contact surface (Cint_k) comprises a coated portion (25) with a first composition configured such that a first dynamic friction coefficient (µd_1) between said external (Sext_i) and internal (Cint_k) contact surfaces at the coated portion (25) is strictly less than a second dynamic friction coefficient (µd_2) between the external face (Fext_i) of the respective wall (Pi) in the extension of which the flap is located and the internal contact surface (Cint_k). Figure for the abstract: 1.

Description

Title of the invention: Packaging sheet, packaging formed from such a packaging sheet, and corresponding manufacturing process

[0001] The present invention relates to a packaging sheet intended to form a package by folding, a method of manufacturing such a packaging sheet and a package obtained by folding such a packaging sheet.

[0002] In the field of packaging, it is known to form a receiving volume for a product to be packaged by means of a folded packaging sheet.

[0003] The packaging sheet, when flat before folding, forms a pattern of a solid comprising the different walls allowing the receiving volume to be delimited.

[0004] The receiving volume is thus obtained by folding the pattern.

[0005] Each wall has an inner face which, after folding, is on the side of the receiving volume and an opposite outer face.

[0006] In general, inks and / or coatings such as varnishes or lacquers, pigmented or not, are applied to all or part of the external faces of the walls, as well as possibly to all or part of the internal faces of the walls of the packaging sheet.

[0007] These inks and coatings can fulfill different technical functions.

[0008] By way of example, they can provide protection for the packaging and / or the product from variations in environmental conditions, such as humidity. They can also facilitate the identification of the packaged product by the user or consumer, in particular by the formation of appropriate color zones or markings on the external faces of the walls.

[0009] In general, at least one of the walls is extended by a closing flap intended to come into contact after folding with an internal face of another wall for closing the packaging, before or after insertion of the product to be packaged.

[0010] For closing the packaging, the closing flap is slid inside the internal volume along the inner face of this other wall.

[0011] On an industrial scale, the positioning of the closing flap is a limiting step for the speed of manufacturing the packaging and / or for the quality of the packaging formed by folding.

[0012] Indeed, the closure flaps tend to be misaligned relative to the corresponding inner face. In particular, they can twist and / or only insert properly partially along this inner face if the speed of the production line is too high.

[0013] One object of the invention is therefore to offer a packaging sheet intended to form a package by folding, making it possible to obtain packaging on an industrial scale with a high level of quality and a high production rate.

[0014] To this end, the invention relates to a packaging sheet intended to form a package by folding, the package being intended to receive a product to be packaged in an internal volume delimited by a plurality of walls, each wall having an internal face and an external face, the packaging sheet comprising said walls before folding as well as at least one closing flap in the extension of a respective wall, an external contact surface of the closing flap being intended to come into contact with an internal contact surface of a respective internal face of another of said walls for the closure of the package,the packaging sheet being characterized in that at least one of the external contact surfaces of the closing flap and the internal contact surface of the respective inner face of said other wall comprises a portion coated with a first composition configured such that a first coefficient of dynamic friction between said external and internal contact surfaces at the level of the coated portion is strictly less than a second coefficient of dynamic friction between the external face of the respective wall in the extension of which the closing flap is located and the internal contact surface of the respective inner face of said other wall when this inner face is devoid of said coated portion.

[0015] The speed of packaging production lines from prior art packaging sheets is most often determined by the nature of the compositions such as inks and / or coatings which are applied to the external faces of the walls before folding the packaging sheet.

[0016] In order to optimize these production lines, in prior art packaging sheets, the closure flaps are covered with the same compositions, in particular the same inks and / or coatings, as the external faces of the walls they extend.

[0017] This arrangement also ensures a satisfactory visual appearance of the packaging when the flap is opened.

[0018] However, the inventor observed that in many cases, these compositions make surfaces sticky or less slippery. As a result, the speed at which prior art packaging can be produced is limited and / or the defect rate in closed packaging at the flap is too high.

[0019] In the packaging sheet according to the invention, the presence of the coated portion allows, by choosing a first suitable composition, to control the first coefficient of dynamic friction between the external contact surface of the closing flap and the internal contact surface of the respective inner face at the level of the coated portion so that this coefficient is strictly less than the second coefficient of dynamic friction between the external face of the respective wall in the extension of which the flap is located and the internal contact surface of the respective inner face.

[0020] This arrangement ensures satisfactory sliding of the closing flap along the inner face with which it is intended to come into contact when closing the packaging, and thus reduces the rate of defective closed packages and / or increases the production rates of these packages.

[0021] Implementing the coated portion in the packaging sheet according to the invention requires a different distribution step for the compositions such as varnishes, inks, and / or coatings during its production. This goes against the general practice of those skilled in the art, who systematically seek to reduce the complexity of the steps required for packaging production and to simplify these steps.

[0022] As previously mentioned, this increased complexity at the packaging sheet production stage before folding is generally advantageous because it allows for a reduction in the rate of defective closed packages and / or an increase in the production rates of these packages.

[0023] According to other advantageous aspects of the invention, the packaging sheet comprises one or more of the following features, taken individually or in any technically possible combination:

[0024] - said coated portion is formed on the external contact surface of the flap of closure;

[0025] - said coated portion extends from a free edge of the closing flap according to at least 50% of the height of the closing flap between said free edge and the respective wall in the extension of which the closing flap is located;

[0026] - the external face of the respective wall in the extension of which is the closing flap is formed by a layer of a second composition chosen from a varnish, a coating or a lacquer;

[0027] - the external contact surface of the closing flap is formed at least in part by a layer of the second composition, the first composition covering the second composition in the coated portion where applicable;

[0028] - the relative difference between the first dynamic friction coefficient and the second coefficient of dynamic friction is greater than or equal to 15%;

[0029] - the second coefficient of dynamic friction is less than or equal to 0.50;

[0030] - the first coefficient of dynamic friction is less than or equal to 0.35.

[0031] The invention also relates to a package comprising at least one packaging sheet according to any one of the preceding claims, the packaging sheet being folded so as to form the internal volume for receiving the packaged product, the package having at least one closed position in which said external contact surface of the closing flap is in contact with said internal contact surface of the respective internal face of said other wall.

[0032] The invention also relates to a method for manufacturing a packaging sheet comprising: a) the supply of a support material in which the packaging sheet is to be formed; and b) a coating step of at least a portion of the support material, intended to form in the packaging sheet said coated portion on one of the external contact surfaces of the closing flap and the internal contact surface of the respective internal face of said other wall, with the first composition.

[0033] According to another advantageous aspect of the invention, the packaging sheet comprises the following feature:

[0034] - the coating step is carried out before a cutting step along a contour the outcome of which a packaging pattern is formed.

[0035] The invention will become clearer upon reading the following description, given solely by way of non-limiting example, and made with reference to the drawings in which:

[0036] [Fig.1] [Fig.1] is a view of a packaging sheet according to the invention from the side of the external faces of the walls;

[0037] [Fig.2] [Fig.2] is a view of the packaging sheet of [Fig.1] from the side of the inner faces of the walls; and

[0038] [Fig.3] [Fig.3] is a view of a package formed by folding the packaging sheet of figures 1 and 2 into an open position.

[0039] The packaging sheet 10 according to the invention is described with reference to figures 1 and 2.

[0040] The packaging sheet 10 is intended to form a package 15 by folding, visible in [Fig.3].

[0041] The packaging 15 is intended to receive a product to be packaged in an internal volume 20 delimited by a plurality of walls.

[0042] Packaging 15 is, for example, primary packaging or secondary packaging.

[0043] The product to be packaged is, for example, an unpackaged solid product, or a primary package of a fluid or viscous product. In the latter case, the package 15 is therefore a secondary package.

[0044] In a particular embodiment, the product to be packaged is a cosmetic product, such as a block of soap, or a primary packaging of a cosmetic product such as a cream or a perfume.

[0045] The packaging 15 has at least one open position, allowing the insertion and / or removal of the product to be packaged, and a closed position in which this insertion and removal are not possible.

[0046] An example of an open position is shown in [Fig.3].

[0047] The internal volume 20 is of any shape provided that it can be formed by folding a flat pattern.

[0048] The internal volume 20 has, for example, the shape of a cylinder, in particular with an elliptical, polygonal or circular base, a pyramidal shape or even a conical shape.

[0049] The walls delimiting the interior volume 20 are designated hereafter individually by the reference signs PI, P2,..., PN, N being an integer designating the total number of these walls or generically by the reference sign Pi, i being an integer between 1 and N.

[0050] One or more of the walls Pi may be flat in the package 15 in the closed position.

[0051] One or more of the walls Pi can be curved in the package 15 in the closed position.

[0052] In the example of figures 1 to 3, the interior volume 20 is parallelepiped and delimited by 6 flat walls PI to P6.

[0053] Each wall Pi has a respective internal face Fint_i, which is on the side of the internal volume 20 in the packaging 15 in the closed position, as seen in Figures 2 and 3, and a respective opposite external face Fext_i, as seen in Figures 1 and 3.

[0054] The packaging 15 is obtained by folding the packaging sheet 10.

[0055] The packaging sheet 10 includes all the walls Pi before folding as well as at least one closing flap Ri in the extension of a respective wall Pi, an external contact surface Sext_i of the closing flap Ri being intended to come into contact with an internal contact surface Cint_k of a respective internal face Fint_k of another wall Pk (k denoting an integer between 1 and N and different from i) for the closure of the packaging 15.

[0056] The external contact surface Sext_i of the closing flap Ri and the internal contact surface Cint_k encompass all the points respectively of the closing flap Ri and of the respective internal face Fint_k that are in contact with each other at least temporarily during the passage from an open position of the flap to closure Ri to a closed position of this closure flap Ri for closing the package 15.

[0057] The external contact surface Sext_i of the closing flap Ri is for example formed by the entirety of an external face of the closing flap Ri, as shown in [Fig.1].

[0058] The internal contact surface Cint_k is for example formed by a fraction of the internal face Fint_k of the respective wall Pk, as shown in [Fig.2], with an area equal to that of the external contact surface Sext_i of the corresponding closing flap Ri.

[0059] When flat, the packaging sheet 10 therefore forms a pattern of the solid delimiting the internal volume 20.

[0060] In the example of figures 1 to 3, the wall P5 is extended by a closing flap R5, of which an external contact surface Sext_5 is intended to come into contact with an internal contact surface Cint_3 of the internal face Fint_3 of the wall P3.

[0061] In this example, the wall P6 is extended by a closing flap R6, an external contact surface Sext_6 of which is intended to come into contact with an internal contact surface Cint_l of the inner face Fint_l of the wall PL

[0062] The closing flap Ri extends from one side of the respective wall Pi to a free edge Bi over a height Hi.

[0063] On [Fig.1], the closing flap R5 has a free edge B5 and extends a height H5 between the free edge B5 and the wall P5.

[0064] Optionally, the closing flap Ri has one or more rounded or beveled edges extending from the respective wall Pi to the free edge Bi.

[0065] This is the case for flaps R5 and R6 of [Fig.1].

[0066] This arrangement makes it easier to put in place the closing flap Ri for the transition to the closed position of the packaging 15.

[0067] Optionally, the packaging sheet includes at least one additional flap RAi extending from a respective wall Pi.

[0068] One or more of the additional flaps RAi can be configured to allow the formation of the package 15 by gluing.

[0069] This is particularly the case for the additional flap RAI in figures 1 to 3, intended to be glued onto the inner face Fint_4.

[0070] One or more of the additional flaps RAi can be configured to be simply folded directly over the inner volume 20 in the package 15 in the closed position.

[0071] This is particularly the case for the additional flaps RA2a, RA4a, RA2b and RA4b in figures 1 to 3.

[0072] The packaging sheet 10 is formed in a support material whose nature and / or thickness in a direction orthogonal to the internal faces Fint_i and Fext_i of a given wall Pi are chosen to allow the packaging 15 to support the weight of the product to be packaged in the closed position without significant deformation and to allow the folding of the packaging sheet 10 at the edges of the walls concerned.

[0073] The support material is single-layer or multi-layer.

[0074] The support material is for example chosen from a paper pulp-based material, such as paper or cardboard, or a plastic material, such as poly(ethylbenzene-1,4-dicarboxylate) (also called polyethylene terephthalate, abbreviated PET) or polypropylene (abbreviated PP).

[0075] The paper or cardboard may contain virgin and / or recycled cellulose fibers.

[0076] By way of example, paper or cardboard may have a basis weight between 150 g / m2 and 600 g / m2 and a thickness e between 180 pm and 800 pm.

[0077] The support material has a front side on which the external faces Fext_i of the walls Pi are formed and a back side on which the internal faces Fint_i of the walls Pi are formed.

[0078] The packaging sheet 10 may include one or more layers of coating applied to all or part of the back of the support material and / or all or part of the front of the support material.

[0079] The coating layer can, in a known manner, be configured to impart a color to the support material and / or to form an insulating barrier, in particular for contact with a greasy or wet body or a food product.

[0080] The packaging sheet 10 may include one or more layers of varnish applied to all or part of the back of the support material and / or all or part of the front of the support material.

[0081] The varnish layer is configured to give the support material a specific appearance, including a glossy, satin or matte appearance and / or an iridescent or pearlescent appearance, and / or a specific feel, including a velvety feel or a rough feel.

[0082] One or more walls Pi of the packaging sheet 10 may be printed and / or embossed on the side of the respective external faces Fext_i and / or on the side of the respective internal faces Fint_i.

[0083] According to the invention, at least one of the external contact surface Sext_i of the closing flap R_i and the internal contact surface Cint_k of the respective internal face Fint_k of the other wall Pk comprises a coated portion 25 coated with a first composition configured such that a first coefficient of dynamic friction pd_l between said external contact surfaces Sext_i and internal contact surfaces Cint_k at the level of the coated portion 25 is strictly less than a second coefficient of dynamic friction pd_2 between the external face Fext_i of the respective wall Pi in the extension of which is the closing flap R_i and the internal contact surface Cint_k of the respective internal face Fint_k of said other wall Pk when this internal face Fint_k is devoid of said coated portion 25.

[0084] In the case where the coated portion 25 is included in the internal contact surface Cint_k of the respective internal face Fint_k of the other wall Pk, the second dynamic friction coefficient pa_2 is therefore measured in the absence of the coated portion 25.

[0085] The coefficient of dynamic friction between two given plane surfaces is defined as the ratio of the magnitude of the dynamic friction force, acting tangentially to the two surfaces when the two surfaces slide relative to each other, and the normal force acting in a direction orthogonal to these surfaces.

[0086] The first dynamic friction coefficient pd_l and the second dynamic friction coefficient pa_2 are measured in the present application according to the standard DIN EN ISO 8295:1995.

[0087] For the numerical examples provided below, the determination of the first and second dynamic friction coefficients pa_l, Pd_2 was carried out using the BT1-FR0.5TS. D14 testing machine from Zwick / Roell Amsler, including a force sensor, a specimen holder and the "txpert" testing software.

[0088] The first composition is for example chosen from a varnish, a coating and a lacquer.

[0089] The first composition is, for example, a water-based varnish.

[0090] The first composition is, for example, an acrylic varnish or a varnish polyurethane.

[0091] The first composition may be glossy or matte. The glossiness of the first composition is evaluated according to DIN EN ISO 2813:2014. In the

[0092]

[0093] For the purposes of this application, a surface coated with a given composition is considered glossy if its gloss value is strictly greater than 30 gloss units (30 GU). A surface is considered matte for the purposes of this application if its gloss value is less than or equal to 30 GU, in particular between 10 GU and 30 GU. In the case of a cardboard-type support material, the first composition is chosen for example from the UV-curing varnish Glanzlack newV lac® gloss 60UC1500 supplied by Huber and the gloss varnish ACRYLAC® GLOSS 57G1000 supplied by Huber. The first composition is advantageously chosen so that the relative deviation A, calculated according to the formula ^r2"^1 nn and ■> cntrc 'c premier Za — M o ' X 1 Uu / 0 dynamic friction coefficient 1 and the second dynamic friction coefficient pd_2 are greater than or equal to 15%, 20%, 25%, 30%, 40%, 50%, or even 60%.

[0094] It has been observed in particular that, for a production line of a case whose substrate material is Algro Design solid bleached board (SBB, "Solid Bleached Board") with a basis weight of 330 g / m² supplied by Sappi, whose inner faces Fint_i are uncoated and whose outer faces Fext_i are coated with Senosoft® WB FP Mattlack 20F 5000 varnish supplied by Weilburger, for which the second dynamic friction coefficient pd_2 is equal to 0.32, the formation of the coated portion 25 with Glanzlack newV lac® gloss 60UC1500 UV varnish supplied by Huber so as to obtain a first dynamic friction coefficient pd_l equal to 0.24 makes it possible to increase the production rate from 80 pieces per minute up to 150 pieces per minute, i.e. an increase in the production rate of 87.5%, with a Ri flap closure failure rate reduced by at least 50%.

[0095] In a particular embodiment, the first dynamic friction coefficient pd_l is less than or equal to 0.35, 0.30, 0.25, or even 0.20.

[0096] In a particular embodiment, the second dynamic friction coefficient pd_2 is less than or equal to 0.50, or even to 0.45.

[0097] In a particular embodiment, the second dynamic friction coefficient pa_2 is greater than or equal to 0.30, 0.35, 0.40, or even 0.45.

[0098] The distribution of the first composition in the relevant contact surface can be continuous or discontinuous.

[0099] For example, the first composition can be applied so as to form a continuous layer, or a discontinuous pattern comprising a plurality of points and / or straight or non-straight bands.

[0100] In a particular embodiment, shown in figures 1 to 3, the coated portion 25 is formed on the closing flap Ri.

[0101] This arrangement allows for a particularly easy application of the first composition during the production of the packaging sheet 10.

[0102] Alternatively, the coated portion 25 is formed on the internal contact surface Cint_k of the respective internal face Fint_k with which the closing flap Ri is intended to come into contact.

[0103] In a particular embodiment, at least a first coated portion 25 is formed on the closing flap Ri and at least a second coated portion 25 is formed on the respective inner face Fint_k with which the closing flap Ri is intended to come into contact.

[0104] In this case, the first composition used to form the first coated portion 25 and the first composition used to form the second coated portion 25 may be identical or different.

[0105] In this case, the first coated portion 25 and the second coated portion 25 can be partially or totally superimposed or be entirely offset from each other in the package 15 in the closed position.

[0106] In particular, the choice of the nature of the first compositions of the first and second coated portions 25 and of the relative positions of these coated portions 25 makes it possible to manage any aesthetic constraints for the packaging 15 while accelerating its production and / or reducing the production defect rate.

[0107] In a particular embodiment, the area of ​​the coated portion 25 is equal to the area of ​​the external contact surface Sext_i of the closing flap Ri.

[0108] Alternatively, the area of ​​the coated portion 25 is strictly less than the area of ​​the external contact surface Sext_i of the closing flap Ri, in particular less than 95%, 90%, 80%, 70%, or 60% of the area of ​​the external contact surface Sext_i of the closing flap Ri.

[0109] Preferably, the area of ​​the coated portion 25 is greater than 30%, 40%, 50%, advantageously 60% of the external contact surface Sext_i of the closing flap Ri.

[0110] In the case where the coated portion 25 is formed on the closing flap Ri, the coated portion 25 is advantageously formed from the free edge Bi.

[0111] This arrangement facilitates the initiation of the sliding of the closing flap Ri along the respective inner face Fint_k for the closure of the package 15.

[0112] In this case, the coated portion 25 can extend from the free edge Bi of the closing flap Ri by at least 50% of the height Hi of the closing flap, preferably at least 60%, at least 70%, at least 75% or even at least 85% of this height, in particular 100% of this height.

[0113] This arrangement ensures easy sliding of the closing flap Ri along its entire travel along the respective inner face Fint_k, as well as a satisfactory visual appearance at the edge separating the wall Pi from the flap Ri, both in the package 15 in the closed position and when the closing flap Ri begins to be moved for the opening of the package 15 at the wall Pi from the closed position.

[0114] In the case where the coated portion 25 is formed on the respective internal face Fint_k with which the closing flap Ri is intended to come into contact, the coated portion 25 is advantageously formed from a free edge B'i of this internal face Fint_k.

[0115] This arrangement facilitates the initiation of the sliding of the closing flap Ri along the respective inner face Fint_k.

[0116] In this case, the coated portion 25 can extend from the free edge B'i of the inner face Fint_k over a height equal to at least 50% of the height Hi of the closing flap Ri, preferably at least 60%, at least 70%, at least 75% or even at least 85% of this height Hi.

[0117] This arrangement ensures satisfactory sliding of the closing flap Ri along its entire travel along the respective inner face Fint_k, as well as a satisfactory visual appearance at the edge separating the wall Pi from the flap Ri, both in the package 15 in the closed position and when the closing flap Ri is totally or partially positioned outside the inner volume 20.

[0118] In a particular embodiment, the external face Fext_i of the respective wall Pi in the extension of which is the closing flap Ri is itself formed by a layer of a second composition chosen from a varnish, a coating or a lacquer.

[0119] In this case, the external contact surface Sext_i of the closing flap Ri can itself be formed partly or entirely by a layer of said second composition. The coated portion 25, if formed on the closing flap Ri, is then formed above the second composition such that the first composition covers the second composition in the coated portion 25.

[0120] The second composition is for example an acrylic varnish or a water-based varnish, in particular a polyurethane varnish.

[0121] The second composition is advantageously chosen from a matte varnish, a velvet effect varnish (in English, “soft touch”), a satin varnish and a partial glossy effect varnish (in English, “drip off”).

[0122] By way of example, for a cardboard-type material, the second composition can be chosen from the UV varnish Mattlack Litho Offset Mat Varnish E51 of reference 75-600244-0.1200 supplied by Siegwerk and the Senosoft® WB FP Mattlack 20F 5000 varnish supplied by Weilburger.

[0123] The second composition and the first composition are both advantageously varnishes, the first composition being advantageously glossier than the second composition.

[0124] This arrangement allows for an external appearance of the packaging 15 that is matte, satin, velvety to the touch, partially glossy, and / or iridescent, while ensuring proper positioning of the closing flap Ri for closing the packaging.

[0125] A test was carried out using Algro Design 330 g / m² solid bleached board (SBB) supplied by Sappi as the substrate material, the first composition being Glanzlack newV lac® gloss 60UC1500 varnish supplied by Huber, applied at a rate of 1.5 g / m², and the second composition The varnish used was Senosoft® WB FP Mattlack 20F 5000 supplied by Weilburger. For this test, the first dynamic friction coefficient pd_l was 0.24 and the second dynamic friction coefficient pa_2 was 0.32. The coated portion 25 thus formed enabled a 50% reduction in the defect rate during the closing of the closure flap Ri, without any modification to the production line, by increasing the production rate from 80 pieces per minute to 120 pieces per minute.

[0126] The invention also relates to a package 15 comprising at least one packaging sheet 10 according to any one of the embodiments described above, the packaging sheet 10 being folded so as to form the internal volume 20 for receiving the packaged product, the package 15 having at least one closed position in which the external contact surface Sext_i of the closing flap Ri is in contact with the internal contact surface Cint_k of the respective internal face Fint_k.

[0127] The invention further relates to a method for manufacturing a packaging sheet 10 according to any one of the preceding embodiments, the method comprising: a) supplying the support material in which the packaging sheet 10 is to be formed, and b) a coating step of at least a portion of the support material, intended to form in the packaging sheet 10 said coated portion on at least one of the external contact surface Sext_i of the closing flap Ri and the internal contact surface Cint_k of the respective inner face Fint_k, with the first composition.

[0128] This coating step is referred to as the main coating step in the following.

[0129] The process may include, before and / or after the main coating step, one or several chosen from: - a step of supplying the support material, a step of hot stamping at least part of at least one wall Pi and / or at least part of at least one flap Ri and / or at least part of at least one additional flap RAi; - a cold marking step of at least part of at least one wall Pi and / or at least part of at least one flap Ri and / or at least part of at least one additional flap RAi; - a printing step of at least part of at least one wall Pi and / or at least part of at least one flap Ri and / or at least part of at least one additional flap RAi; - an additional step of coating at least part of at least one wall Pi and / or at least part of at least one flap Ri and / or at least part of at least one additional flap RAi using the second composition;

[0130] - an embossing step of the support material; - a cutting step for the support material.

[0131] The main coating step is advantageously carried out on the flat packaging sheet 10, and in particular before a cutting step of the support material according to a contour at the end of which the pattern of the packaging 15 is formed.

[0132] In a first embodiment, at the end of the manufacturing process, the packaging sheet 10 is obtained in unfolded form.

[0133] Alternatively, the manufacturing process comprises one or more steps selected from: - a folding step; - a step of gluing an additional flap RAi onto a wall other than the one it extends or onto another additional flap.

[0134] In this case, the main coating step is advantageously carried out before the folding and / or gluing steps.

Claims

Demands

1. Wrapping sheet (10) intended to form a package (15) by folding, the package (15) being intended to receive a product to be packaged in an internal volume delimited by a plurality of walls (Pi), each wall (Pi) having an inner face (Fint_i) and an outer face (Fext_i), the wrapping sheet (15) comprising said walls (Pi) before folding as well as at least one closing flap (Ri) in the extension of a respective wall (Pi), an external contact surface (Sext_i) of the closing flap (Ri) being intended to come into contact with an internal contact surface (Cint_k) of a respective inner face (Fint_k) of another of said walls (Pk) for the closure of the package (15),the packaging sheet (10) being characterized in that at least one of the external contact surface (Sext_i) of the closing flap (Ri) and the internal contact surface (Cint_k) of the respective inner face (Fint_k) of said other wall (Pk) comprises a coated portion (25) with a first composition configured such that a first coefficient of dynamic friction (pd_l) between said external (Sext_i) and internal (Cint_k) contact surfaces at the level of the coated portion (25) is strictly less than a second coefficient of dynamic friction (pa_2) between the external face (Fext_i) of the respective wall (Pi) in the extension of which is the closing flap (Ri) and the internal contact surface (Cint_k) of the respective inner face (Fint_k) of said other wall (Pk) when this inner face (Fint_k) is devoid of said coated portion (25).

2. Packaging sheet (10) according to claim 1, wherein said coated portion (25) is formed on the external contact surface (Sext_i) of the closing flap (Ri).

3. Packaging sheet (10) according to the preceding claim, wherein said coated portion (25) extends from a free edge (Bi) of the closing flap (Ri) for at least 50% of a height (Hi) of the closing flap (Ri) between said free edge (Bi) and the respective wall (Pi) in the extension of which the closing flap (Ri) is located.

4. Packaging sheet (10) according to any one of the preceding claims, wherein the outer face (Fext_i) of the respective wall (Pi) in the extension of which is the closing flap (Ri) is formed by a layer of a second composition selected from a varnish, a coating or a lacquer.

5. Packaging sheet (10) according to the preceding claim, wherein the external contact surface (Sext_i) of the closing flap (Ri) is formed at least in part by a layer of the second composition, the first composition covering the second composition in the coated portion (25) where appropriate.

6. Wrapping sheet (10) according to any one of the preceding claims, wherein the relative difference (A) between the first dynamic friction coefficient (pd_1) and the second dynamic friction coefficient (pa_2) is greater than or equal to 15%.

7. Wrapping sheet (10) according to any one of the preceding claims, wherein the second dynamic friction coefficient (pd_2) is less than or equal to 0.

50.

8. Wrapping sheet (10) according to any one of the preceding claims, wherein the first dynamic friction coefficient (p <i_l) est inférieur ou égal à 0,35.

9. Packaging (15) comprising at least one packaging sheet (10) according to any one of the preceding claims, the packaging sheet (10) being folded so as to form the internal volume (20) for receiving the packaged product, the packaging (15) having at least one closed position in which said external contact surface (Sext_i) of the closing flap (Ri) is in contact with said internal contact surface (Cint_k) of the respective inner face (Fint_k) of said other wall (Pk).

10. A method for manufacturing a packaging sheet (10) according to any one of claims 1 to 8, the method comprising: a) supplying a support material in which the packaging sheet (10) is to be formed; and b) a step of coating at least a portion of the support material, intended to form in the packaging sheet (10) said coated portion (25) on one of the external contact surfaces (Sext_i) of the closing flap (Ri) and the internal contact surface

11. (Cint_k) of the respective inner face (Fint_k) of said other wall (Pk), with the first composition. Method of manufacturing a packaging sheet (10) according to the preceding claim, wherein the coating step is carried out before a cutting step along a contour at the end of which a pattern of the packaging (15) is formed.

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