Package and manufacturing method in which welds are concealed within the print

Abstract

The present invention relates to a method for manufacturing a tubular body (2) for a package in tube form (1), comprising the steps of: defining the geometrical characteristics of the tubular body (2) to be produced; creating an initial image (6) covering the surface of the tubular body (2) to be produced; creating an intermediate image (8) from the initial image (6) by adding lateral strips (13) to one of the edges of the initial image (6); printing at least one intermediate image (8) on a sheet; cutting small strips on each lateral side of the intermediate image (8) to form a final image (10); and shaping the tubular body (2) and the sheet as an edge-to-edge assembly to obtain design continuity between the right and left edges of the image.

Description

REFERENCE TO RELATED APPLICATIONS

[0001] This PCT application claims priority to an earlier European patent application No. 21170375.6, filed on April 26, 2021 in the name of AISAPACK HOLDING SA, the contents of which are incorporated herein by reference in their entirety. [Technical field]

[0002] The invention is within the field of packaging formed by printed sheets which are welded or joined. The invention more particularly relates to a package with a tubular body obtained by butt welding or joining of sheets. The invention applies in the field of packaging, in particular in the field of recyclable flexible tubes intended to contain cream or paste products, or in the field of cans for containing liquids instead of aluminium, or in the field of flasks for cosmetics. State of the art

[0003] Butt welding of sheet structures to produce tube bodies has already been described in the prior art, in particular in US Pat. No. 5,569,144, US Pat. No. 4,733,800, EP Pat. No. 2,720,849, EP Pat. No. 2,720,850, EP Pat. No. 2007,567, EP Pat. No. 2004,506, EP Pat. No. 2004,389.

[0004] EP 2720849 and EP 2720850 teach a method for butt welding multi-layer sheets to form a tubular body. EP 2720849 proposes to bevel cut the edges at different angles to form a slight overlap of the edges of the sheets in the weld zone. EP 2720849 teaches, for the part of the bevel cut, to bevel cut the edges of the sheets and to apply circumferential pressure to said edges during the welding operation. These publications do not teach how to obtain a continuity of design in the welded zone to hide the weld.

[0005] EP 2007567, EP 2004506 and EP 2004389 propose in particular to add a reinforcing strip to the end butt welds in order for the welds to have sufficient strength. The butt welds proposed in these publications also allow for tubular bodies with a decoration in the weld zone. The possibility of masking the weld zone by a decoration is a great advantage in the field of packaging, especially when aimed at the cosmetics sector. However, the prior art does not allow for a continuity of the decoration on the two sides of the weld to be obtained with high precision.

[0006] EP 2 720 849, EP 2 720 850, EP 2007 567, EP 2004 506 and EP 2004 389 allow a significant improvement in the aesthetics of the welded package, since they allow decorations to be applied within the weld zone. However, the designs that can be used within the weld zone generally remain limited, since a slight offset is regularly observed between the left and right parts of the weld.

[0007] EP 3300881 A1 proposes a method for cutting the edge of a printed sheet before welding to improve the weld aesthetics of the end of the printed sheet, said end being overlap welded. The method proposes to use the edge of the printed snapshot to control the position of the cut. This method makes it possible to improve the aesthetics of the weld by overlapping, but it cannot be applied to butt welding to solve the problem of offset of the pattern on both sides of the weld.

[0008] The aim of the present invention is to improve the known method.

[0009] More particularly, the object of the invention is to propose a simple means for producing a tubular body decorated over its entire surface, where no welds are visible.

[0010] The present invention makes it possible to remedy the above-mentioned drawbacks, in particular by producing butt welds with design continuity in the welded zone in order to hide the weld and avoid the visible offsets that occur in the state of the art.

[0011] The invention relates to a method for producing tubes with a so-called "360°" decoration, i.e. a decoration extending over the entire circumference of the tube, by welding printed sheets.

[0012] The invention particularly relates to a method that makes it possible to hide the welding zone in the design.

[0013] More specifically, the invention relates to a method for the continuous manufacture of tubular bodies, which comprises at least printing a series of consecutive images on a reel-packaged sheet, unloading said sheet, thus defining a scroll direction, cutting the lateral edges of said sheet so that the remaining width of said sheet corresponds to the diameter of the tubular body to be produced, forming the sheet into a tubular geometric shape, butt-welding the lateral edges of the sheet, and then cutting the tubular bodies perpendicular to the scroll direction and synchronous with the images.

[0014] In an embodiment, the invention is characterized in particular by the fact that the width of the printed image on the sheet is greater than the circumference of the tubular body to be produced and by the fact that a first portion located at the left edge of the image is identical to a second portion located at the right edge of the image, said left and right portions forming two parallel lateral strips of identical width.

[0015] According to an embodiment of the invention, the operation of cutting the edges of the sheet is carried out in order to match the final width of the sheet with the diameter of the tubular body to be produced. According to an embodiment of the invention, the edge cut is contained within the side strips.

[0016] According to an embodiment of the invention, the diameter of the tubular body to be produced is used to define the dimensions of an image, called the "initial image". The width of the initial image is defined by the circumference of the tubular body to be produced, and the height of the initial image is defined by the length of the tubular body.

[0017] According to an embodiment of the invention, the initial image is used to generate an image called "intermediate image" by adding to the left of the initial image a lateral strip corresponding to a copy of the right lateral edge of the initial image, or conversely, by adding to the right of the initial image a lateral edge corresponding to a copy of the left lateral edge of the initial image. The intermediate image thus comprises at least two identical zones located at the lateral edges.

[0018] A series of intermediate images are printed on sheets, which are then packaged on a parent reel, with the lateral edges of the images parallel to the unwinding direction of the sheet. The printing of the sheets can be done in one or more tracks. Routine cutting of the printed sheets allows for width adjustment and packaging of the intermediate images into "child reels", which contain only a single track of images.

[0019] In the process of manufacturing a tubular body according to an embodiment of the invention, the width of the intermediate image is then reduced by cutting small strips at each lateral edge. The image obtained after the edges are cut is called the "final image" and is characterized by the continuity of the design between the left and right lateral edges.

[0020] When carrying out an embodiment of the invention, the measure of continuity of the design between the left and right edges of the final image is used to adjust the remaining width of the sheet, which predetermines the diameter of the tubular body that will be obtained by juxtaposing and butt-welding the lateral edges of the sheet after cutting of the small strips on each lateral edge. Finally, a tubular body with a 360° decoration is obtained.

[0021] Generally, differences are observed between the theoretical and the actual diameter of the tubular body. These small differences may be due to dimensional variations of the sheet under the influence of mechanical and / or thermal stresses. Therefore, an optimization of the final width of the sheet and the diameter of the tubular body according to the invention is necessary to obtain the 360° decoration specified in the present invention.

[0022] The inherent variations in the manufacturing equipment result in greater or lesser variations in the manufactured products. These variations can be reduced by using more or less sophisticated adjustment methods. However, these adjustment methods do not by themselves make it possible to obtain the desired visual quality in the butt welds and the continuity of the design on both sides of the weld.

[0023] One great advantage of the invention and embodiments of the invention is that it makes it possible to largely overcome variations in the butt welds that may be caused by manufacturing equipment. Thus, according to embodiments of the invention, the width of the printed side strip is greater than the amplitude of the positional variations of the sheet perpendicular to the scroll axis. For example, the position of the sheet may vary perpendicular to the scroll axis in printing or cutting the edge of the sheet. According to embodiments of the invention, the width of the side strip is such that the cutting of the edge is always located within said side strip.

[0024] According to an embodiment of the invention, the method can be optimized to reduce the waste caused by the cutting of the edges. To this end, a sheet guide system can be used to limit the variations of the method. Thus, a guide system using one or more sensors that detect the lateral position of the strip during printing makes it possible to adjust the lateral position of the sheet and thus reduce the positional variations of the image relative to the edge of the sheet. Alternatively, fixed guide means can be used.

[0025] A second system preferably used allows adjusting the position of the sheet during the cutting of the edges, prior to the operation of forming the tubular body. According to a preferred embodiment, the second system comprises one or more sensors which detect the lateral position of the image and adjust the lateral position of the sheet during the cutting of the edges. According to an alternative method, a sensor detects the edge of the sheet for adjustment. According to another embodiment, fixed guide means are used.

[0026] According to an embodiment of the invention, the method also comprises a step of final adjusting the diameter of the tubular body, the diameter of the tubular body being predefined by the final image. A first embodiment consists of adjusting the diameter before the welding operation. An alternative embodiment consists of adjusting the diameter simultaneously with the welding operation.

[0027] According to an embodiment, the present invention also relates to a package at least partly produced by the method according to the invention.

[0028] In accordance with these embodiments, the present invention more specifically relates to packages with hidden welds in their design.

[0029] More specifically, the present invention relates to a package comprising at least one tubular body made from sheets decorated and printed and butt-welded in accordance with the principles of the present invention.

[0030] More specifically, according to an embodiment, the invention relates to a tube comprising a flexible tubular body and decorated according to the method described herein, one end of which is connected to a tube head and the other end of which is clamped and welded on the flexible tubular body itself, forming a so-called final weld. The tube head comprises at least one orifice for extracting the product contained in the package. The package may also comprise means for opening and closing said package.

[0031] The tube as described above preferably comprises two main faces geometrically assembled by a final weld, possibly by an opening system such as a hinged plug, etc. The two main faces of the tube are used, for example, as vectors for communication with decorations, images or suitable printing.

[0032] The invention makes it possible in particular to obtain a package with a complex decoration without discontinuities on each side. According to an embodiment of the invention, the longitudinal welds are hidden in one of the two sides.

[0033] The principles of the present invention make it possible, for example, to place a weld on one of the faces of the package without the weld being visible and without altering the aesthetics of the tube.

[0034] According to one embodiment of the invention, the butt welding includes adding material on the side of the inner surface of the tubular body, and the additional material reinforces the butt weld. According to one embodiment of the invention, the additional material can be a welded strip or an extrusion. This additional material can be placed on the inner surface of the tubular body or at least partially embedded within the thickness of the tubular body.

[0035] According to embodiments of the present invention, the welds are difficult to detect on the decorated exterior surface of the package and therefore are invisible to the user.

[0036] Embodiments of the present invention allow for continuity of design on both sides of the weld, thus avoiding discontinuities in pattern or color at the weld.

[0037] Embodiments of the present invention allow for the use of all surfaces of the tubular body as a communication vector.

[0038] Embodiments of the present invention allow for welds to be located at optimal points to obtain high package strength together with optimal aesthetic qualities.

[0039] In an embodiment, the present invention relates to a method for manufacturing a tubular body for a package, said method comprising, in particular, the steps of: -) defining the geometric characteristics of the tubular body to be produced; -) creating an initial image covering the surface of the tubular body to be produced, said initial image having a right side edge and a left side edge; -) creating an intermediate image from the initial image by adding a side strip to one of the edges of the initial image, the side strip including a copy of the other of the edges of the initial image; -) printing at least one intermediate image on the sheet, the intermediate image being arranged such that the lateral edges of the image are parallel to the unwinding direction of the sheet; -) cutting strips, preferably small strips, on each lateral side of the intermediate image to form a final image; -) shaping the sheet as a tubular body and an edge-to-edge assembly to obtain design continuity between the right and left edges of the image.

[0040] In an embodiment, a series of intermediate images may be printed onto the sheet.

[0041] In an embodiment, the image may be printed on several parallel tracks and the sheet may be rolled up to obtain a single track of the image.

[0042] In an embodiment, the characteristic of the tubular body may be the diameter and / or the length and / or the thickness.

[0043] In embodiments, the initial image may include a design formed by an image, a drawing, a solid or shaded color, or a combination thereof.

[0044] In embodiments, edge-to-edge assembly may be performed by welding the sheets or by extruding the tubular body onto the inner surface of the sheet.

[0045] In an embodiment, edge-to-edge welding may include heating, pressing, and cooling the edges of the sheets.

[0046] In an embodiment, after the welding operation, material is added to reinforce the welded zone, for example, on the inner surface of the tubular body and / or on the outer surface of the tubular body.

[0047] In an embodiment, the addition of material may be in the form of plastic strips welded or bonded to the edges of the sheet, or by the addition of beads of extrusion material.

[0048] In an embodiment, the tubular body may be cut into segments, and the cutting into segments is synchronized with the image.

[0049] In embodiments, the sheet may be a monolayer or multilayer film.

[0050] In an embodiment, the sheet may be a laminate.

[0051] In embodiments, the sheet may be based on synthetic materials, cellulose, bio-sourced materials, recycled materials, biodegradable materials, or mixtures of said materials.

[0052] In an embodiment, the present invention relates to a package comprising a tubular body obtained by the method described in the present application.

[0053] In embodiments, the package may be a tube, or a flask, or a can, or any other type of package. [Brief description of the drawings]

[0054] [Figure 1] 1 shows an example of an edge-to-edge weld according to prior art EP 2 720 850 A1. [Diagram 2] 1 shows the operation of cutting the lateral edges of a sheet according to the prior art EP 3 300 881 A1. [Diagram 3] The main steps of the tube manufacturing method according to the invention will now be described. [Figure 4] Shown are so-called "initial", "intermediate" and "final" images used in the present invention. [Diagram 5] 13 shows the step of cutting small strips on either side of the intermediate image. [Figure 6] 1 shows a tube with a 360° design obtained according to the invention. [Figure 7] 7 shows intermediate images used to fabricate the tube shown in FIG. Detailed Description

[0055] 1 tube 2 Tubular body 3 Longitudinal welds 4 Tube Head 5 End welds 6 Initial images 7 Initial Image Width 8 Intermediate Images 9 Intermediate Image Width 10 Final image 11 Final image width 12 Sheet width 13 Side Strips 14 Width of side strip 15 Position of left cut 16 Right cut position 17 Unprinted sheet edges

[0056] 3 shows an example of the steps of the method according to the invention for the production by welding of a tubular body with a 360° design with hidden welds in the continuity of the design. According to one embodiment of the invention, the method comprises, for example, the steps described below.

[0057] The first step involves defining the geometrical characteristics of the tubular body to be produced, i.e. for example the diameter of the tubular body to be produced, the width of the tubular body to be produced and the thickness of the tubular body to be produced. The first step of the method also involves the creation of a design that is desired to be shown all around the tubular body. In the context of the present invention, the design can be of any kind, such as an image, a drawing, a solid or shaded color, or a combination thereof. Thus, an image, called the initial image, is created, the width and height of which correspond respectively to the circumference and length of the tubular body. The initial image therefore completely covers the entire surface of the tubular body.

[0058] The second step of the method involves creating an intermediate image by adding to the left of the initial image a lateral strip corresponding to a copy of the right edge of the initial image, or vice versa, The intermediate image obtained is larger than the initial image, as a result of which the width of the intermediate image is greater than the circumference of the tubular body to be produced.

[0059] The third step involves printing a series of intermediate images on sheets, which are then bound, for example on reels. The intermediate images are arranged so that the lateral edges of the images are parallel to the unwinding direction of the sheet. Depending on the width of the sheet, the images can be printed in one or more mutually parallel tracks. If the images are printed in several tracks, the printed sheets are then wound up for binding, obtaining a single track of intermediate images per reel.

[0060] The fourth step of the method, called "trimming", involves cutting small strips on each lateral side of the intermediate image to obtain an image called "final image", which contains the continuity of the decoration between the left edge of the final image and the right edge of the final image when formed into a tubular body. The width of the final image corresponds substantially to the circumference of the tube to be produced. Preferably, the fourth step is performed in a continuous tubular body production method, where the printed sheet is unrolled, trimmed, formed into a tube and assembled edge-to-edge (e.g. by welding). A precise adjustment of the width of the final image is performed to obtain the continuity of the design between the left and right edges of the image.

[0061] The fifth step involves forming the printed sheet into a tubular geometry, with the printed surface visible on the outside of the tube. In this step, the ends of the printed sheet are placed edge-to-edge and the diameter of the tubular body is adjusted so that the ends of the sheet meet without forming overlaps or crimps in the print zone.

[0062] The sixth step involves edge-to-edge welding or joining of the ends of the sheets. Preferably, the assembly is carried out using the operations of heating, pressing and cooling of the ends of the sheets. Edge-to-edge welding may involve the addition of material reinforcing the welded zone. This addition of material may be in the form of a plastic strip welded or joined onto the ends of the sheets, or by the addition of a bead of extrusion material. Preferably, the addition of the reinforcement is made on the inner surface of the tube. The tubular body may also include reinforcement on the outer surface of the weld.

[0063] Finally, the seventh step involves cutting the tubular body into segments of similar length, the cutting operation being synchronized with the image. The final cutting operation results in a tubular body decorated all around, with the welds hidden within the print.

[0064] Figure 4 shows, as a non-limiting example, an example of an initial image 6, an intermediate image 8 and a final image 10 with a design made up of images / drawings. The initial image 6 has a width 7 corresponding to the circumference of the outer surface of the tubular body to be produced. The width 7 of the initial image is measured perpendicular to the unwinding direction of the sheet and to the axis of the tubular body. The initial image 6 is a virtual image (not printed) corresponding to the design one wishes to obtain on the tubular body.

[0065] FIG. 4 shows an intermediate image 8 constructed by adding, to the left of the initial image, a strip 13 that is a copy of the strip 13 on the right of the initial image. Another intermediate image (not shown) can be obtained by copying, to the right of the initial image, the strip 13 on the left of the initial image. In all cases, the intermediate image is characterized by the fact that it contains two identical lateral strips 13 (one is a copy of the other). The lateral strips 13 can contain images, drawings, plain or shaded colors, or combinations thereof, etc., the important factor being that the two lateral edges should be identical. The intermediate image 8 thus obtained has a width 9 that is greater than the circumference of the tube it is desired to produce. The intermediate image 8 is then printed on a sheet that is used to produce the tubular body by welding the ends.

[0066] Since the decoration will ultimately be located on a cylinder with a 360° design, it is a wise implementation to optimize the primary image to select the zones where the welds will be located on the package. Generally, in the case of a tube form package, it is avoided, for example, to have a weld located at the fold formed by the end welds 5 of the package.

[0067] FIG. 4 also shows the final image 10 obtained in an operation of trimming the edges of the sheet. This operation consists in particular in taking a small strip from each side of the sheet in order to create a continuity of the decoration between the left and right edges of the sheet. This trimming operation is necessary in the manufacturing process in order to remove edges of the sheet that may have been damaged during storage on the reel and to adjust the width of the sheet with high precision before the formation of the tubular body. FIG. 4 shows the width 11 of the final image adjusted to obtain the continuity of the design between the left and right edges, i.e. the continuity that will be created during edge-to-edge welding of the sheet formed into a tubular body. The positions of the cuts 15 and 16 are located inside the strip 13. The distance between the cut positions 15 and 16 is set during the production, which allows the width 11 to have negligible variations throughout the production.

[0068] FIG. 5 shows one of the advantages of the invention, which makes it possible to overcome variations in the lateral positioning of the sheets in the manufacturing method. FIG. 5 shows in amplified form the principle of the invention, which makes it possible to guarantee the continuity of the design between the left edge of the image and the right edge of the image, even if the image is displaced laterally. According to the principle of the invention, the distance between the cutting positions 15 and 16 is constant, so that the width 11 of the final image is constant, even if the image is displaced laterally relative to the cutting positions. The method according to the invention makes it possible to overcome the variations in the lateral position, as long as the variations in the positioning are contained within the lateral strips 13 of width 14, since the strips 13 contain the same image or part of an image. The invention thus makes it possible to overcome the variations in the lateral position of the image relative to the edge of the sheet of width 12, said sheet being able to include a non-printed lateral portion 17. The invention also makes it possible to overcome the variations in the position of the printed sheet relative to the cutting positions 15 and 16. The variations shown in FIG. 5 are exemplary and in reality appear over much longer sheet lengths, which may amount to several hundred meters. The invention also makes it possible to overcome variations that appear when changing reels, for example when the design on the second reel is offset laterally relative to the design on the preceding reel.

[0069] Figure 6 shows a package in tube form 1 with circumferential design continuity obtained by the method according to the invention. The tube 1 comprises a tubular body 2 fixed to a tube head 4 with an orifice for extracting the product contained in the package. The tube head 4 is generally associated with an opening and closing system such as a plug (not shown). The tubular body 2 is closed on the side of the tube opposite the head by an end weld 5. The package 1 shown in Figure 6 is characterized in that the longitudinal welds 3 of the tubular body 2 are completely hidden in the image with design continuity on both sides of the longitudinal welds 3.

[0070] Figure 7 shows an intermediate image 8 making it possible to produce the package shown in figure 6. The intermediate image comprises two identical lateral strips 13 of width 14 located at the edges of the image. Cutting positions 15 and 16 of fixed width 11 corresponding to the circumference of the tube to be produced make it possible to obtain the final image by a trimming operation. According to the invention, the cutting positions 15, 16 can be moved laterally within the strips 13 while maintaining a constant separation distance 11. According to the invention, the final image obtained after the trimming operation has a continuity of design between the left and right edges of the image. This continuity of design is on the tubular body on both sides of the longitudinal weld.

[0071] Figure 7 shows an intermediate image 8 of width 9 printed on a sheet of width 12. Cutting positions 15 and 16 define the final image of width 11 obtained after the trimming operation and before shaping into a tubular body. The invention makes it possible to overcome small variations in the relative lateral positions between the cutting tools 15, 16, the intermediate image and the edge of the sheet.

[0072] According to a preferred embodiment of the invention, means are used in the method to guide the sheet laterally and to reduce the amplitude of the fluctuations. For example, it is advantageous to use strip guides controlled by cameras that detect either the edge of the sheet or the lateral position of the image. During the trimming operation, the preferred method is to adjust the lateral position of the sheet depending on the position of the image. This makes it possible to limit the waste of the trimming operation.

[0073] According to an embodiment of the invention, the width 14 of the strip 13 must be larger than the amplitude of the variation of the lateral position of the intermediate image 8 relative to the cutting positions 15, 16. According to the invention, the width 14 of the strip 13 is, for example, 0.5-10 mm, preferably 1-3 mm.

[0074] According to an embodiment of the present invention, the width of the intermediate image 13 is, for example, 1 to 10 mm larger, preferably 2 to 4 mm larger than the circumference of the tubular body.

[0075] According to an embodiment of the present invention, the width of the final image is equal to the width of the initial image taking into account possible sheet shrinkage during the printing operation.

[0076] According to an embodiment of the present invention, the circumference of the tubular body is equal to the width of the final image taking into account the shrinkage of the sheets during the edge-to-edge welding operation.

[0077] The sheets used in the context of the present invention may be single- or multi-layer sheets having a thickness of between 20 and 500 microns, preferably between 150 and 450 microns.

[0078] The sheets may be based on plastic resins, bio-sourced materials, recycled materials, or biodegradable materials.

[0079] The printing of the sheet can be done on a surface or can be trapped in a multi-layer structure of the sheet. In the second case, the printing of the sheet is followed by a lamination step to trap the printing.

[0080] The sheets can be printed by using several techniques, separately or in combination, such as, for example, offset printing, UV flexography, screen printing, typography, thermal transfer printing, digital printing, etc.

[0081] The tubular body is manufactured by edge-to-edge welding. Many configurations described in the prior art can be usefully associated with the present invention. Thus, the edges of the sheets can be cut at right angles or at an angle, as proposed for example in EP 2720849. The edge-to-edge weld can be reinforced by inner and / or outer strips, as proposed for example in EP 2007567, EP 2004506 and EP 2004389. One alternative consists in reinforcing the edge-to-edge weld with a weld bead, as described for example in EP 2089213.

[0082] In an embodiment, the sheet may be, for example: -) cellulose, i.e. compositions commonly used in the paper industry. These compositions generally contain a majority of cellulose (e.g. 70% or more), a mineral filler (e.g. calcium carbonate or kaolin), a colorant or optical brightener, a binder (e.g. starch or latex) and possibly lignin. According to the invention, the package may also contain thin barrier layers, e.g. moisture or oxygen barrier layers. These layers are, for example, thermoplastic resins such as PE, PP, EVOH, PVOH, PLA, or thin layers such as SiOx layers or metallized layers, or coatings or nanocoatings. -) multilayer films as described in WO 2013 / 186723, which have reinforcing elements as described therein; -) laminates as described in WO 2007 / 113782, -) the strips described in WO 2009 / 125330 using the welding methods described therein, -) laminates as described in WO 2007 / 113781, -) laminates as described in WO 2008 / 038206, -) Laminates as described in WO 2007 / 113780 and the like.

[0083] A variant of the invention consists in producing the tubular body by extrusion labeling according to the methods described in WO 2015 / 159234 and WO 2018 / 051235. In this variant, a thin sheet is printed according to the principles of the invention. In the continuous extrusion labeling methods described in WO 2015 / 159234 and WO 2018 / 051235, the sheet is then trimmed according to the invention before forming the sheet into a tubular geometry. The tubular body is then extruded onto the inner surface of the sheet formed into a tubular geometry. The sheet can thus be, for example, a monolayer film as described in these publications, or another equivalent film used in the field of packaging as described in the present application.

[0084] The embodiments described in this application are therefore described as illustrative examples and should not be considered as limiting. Other embodiments may, for example, use equivalent means to those described. The embodiments may be combined with each other depending on the circumstances, and means used in one embodiment may also be used in another embodiment.

Claims

1. 1. A method for manufacturing a tubular body for a package, the method comprising: - defining geometric characteristics of the tubular body to be produced; creating an initial image covering a surface of the tubular body to be produced, the initial image having a right side edge and a left side edge; creating an intermediate image from the initial image by adding a side strip to one of the edges of the initial image, the side strip including a copy of the other of the edges of the initial image; printing at least one intermediate image on the sheet, the intermediate image being oriented such that the lateral edges of the image are parallel to the unwinding direction of the sheet; cutting strips from each lateral edge of the intermediate image to form a final image; forming the sheet into a tubular body and an edge-to-edge assembly to obtain design continuity between the right and left edges of the image; A method comprising:

2. The method of claim 1 , wherein the series of intermediate images is printed on a sheet.

3. 2. The method of claim 1, wherein the image is printed on several parallel tracks and the sheet is rolled up to obtain a single track of the image.

4. The method of claim 1 , wherein the characteristic of the tubular body is a diameter and / or a length and / or a thickness.

5. The method of claim 1 , wherein the initial image comprises a design formed by an image, a drawing, a solid or shaded color, or a combination thereof.

6. The method of claim 1 , wherein the edge-to-edge assembly is fabricated by welding the sheets together or by extruding a tubular body onto an inner surface of the sheets.

7. The method of claim 1 , wherein edge-to-edge welding comprises heating, pressing, and cooling the edges of the sheets.

8. 8. The method according to claim 6 or 7, wherein after the welding operation, material is added to reinforce the welded zone, said addition of material being performed on the inner surface of the tubular body and / or on the outer surface of the tubular body.

9. 9. The method of claim 8, wherein the addition of material is in the form of plastic strips welded or bonded onto the ends of the sheet, or by the addition of beads of extrusion material.

10. The method of claim 1 , wherein the tubular body is cut into segments, and the cutting into segments is synchronized with the image.

11. The method of claim 1 , wherein the sheet is a monolayer or multilayer film.

12. The method of claim 1 , wherein the sheet is a laminate.

13. The method of claim 1 , wherein the sheet is based on synthetic materials, cellulose, bio-sourced materials, recycled materials, biodegradable materials, or mixtures of said materials.

14. A tubular body comprising a sheet having a plurality of lateral edges, the sheet bearing a print forming a final image, the plurality of lateral edges of the sheet being edge-to-edge welded to one another such that the welds are concealed within the print to form continuity of the design of the image.

15. A tubular body as described in claim 14, comprising added material, the addition of material being performed on an inner surface of the tubular body and / or an outer surface of the tubular body.

16. A tubular body as described in claim 15, wherein the addition of material is in the form of a plastic strip welded or bonded onto the end of the sheet or by the addition of a bead of extruded material.

17. The tubular body of claim 14, wherein the sheet is a monolayer or multilayer film.

18. The tubular body of claim 14, wherein the sheet is a laminate.

19. The tubular body of claim 14, wherein the sheet is based on a synthetic material, cellulose, a biosourced material, a recycled material, a biodegradable material, or a mixture of said materials.

Images