Tubular packaging manufacturing method

Abstract

Method of manufacturing a tubular packaging by welding the end of a tubular body (2) to a component (3), said method comprising the following steps: A. supplying a component (3), such as shoulder, a cap or a bottom; B. supplying a tubular body (2); C. heating (12) the interface (14, 14') of the component (3) and the tubular body (2) to be welded; D. positioning the zones to be welded (14, 14'); E. pressurizing (18) and cooling (19) the weld (21); in which method, during heating of the interface (14), the outer face (9) of the tubular body is actively cooled (10, 11) during step C, such that the surface layer (9) of the tubular body (2) does not flow during step E and a bead (22) of material originating from the tubular body (2) is formed at the end of the surface layer (9).

Description

[0001] P4279PC01 / 101-192 spec dpt

[0002] TUBULAR PACKAGING MANUFACTURING METHOD

[0003] CORRESPONDING APPLICATION

[0004] The present application claims priority to the earlier European patent application N° EP24203413.0, filed on September 27, 2024 in the name of AISAPACK HOLDING SA, the content of this earlier application being incorporated by reference in its entirety in the present application.

[0005] TECHNICAL FIELD

[0006] The invention relates to the field of the welding manufacture of flexible packaging tubes comprising at least one flexible tubular body joined to a component by welding. According to the invention, the component may be, for example, a tube head, an opening / closing system or a closed end such as a bottom.

[0007] PRIOR ART

[0008] Publication EP 2279 072 describes a system for welding a tube head to a tubular body. The system described comprises a mandrel on which the tubular body and the tube head to be welded to one another are placed. To perform the welding, the system comprises, on the one hand, heating means for heating the tubular body / tube head interface at the location where the weld is to be made and also cooling means. These cooling means comprise a cooling ring that bears on the outside of the tubular body and an insulation ring located between the cooling ring and a forming ring. During the welding method, the end of the tubular body is subjected, on the one hand, to heating on its internal portion intended to be welded to the tube head, and, on the other hand, to cooling on its external portion by the cooling ring; however, this cooling is not applied to the portion of the tube located at the level of the insulation ring, which corresponds to the very end of the tubular body, and that portion is itself also heated. P4279PC01 / 101-192 spec dpt

[0009] SUMMARY OF THE INVENTION

[0010] With the emergence of mono-material, lightweight packaging containing larger amounts of recycled resin, the visual quality of the weld between the tubular body and the component can deteriorate. In the context of the present invention, the term “mono-material” is understood to mean a packaging or a portion of a packaging (such as, for example, a tubular body) that is essentially formed of the same material or materials of the same type or family, typically in the order of 95%. On the other hand, with the advent of lighter caps, many caps no longer cover the weld area, making even minor visual defects in this zone more critical.

[0011] The object of the invention is to remedy assembly defects when welding a component to a tubular body formed, in particular, by extrusion, by extrusionlabelling (see publications WO 2015 / 159234 and WO 2018 / 051235), or by injection. These tubular bodies tend to deform when heated due to internal stresses created during their manufacture, which causes problems when welding them to a component.

[0012] The most frequent defects that can appear at the weld between the component and the tubular body, particularly when using the method and system described in publication EP 2 279 072 cited above, are as follows:

[0013] - a defect in the form of a crease or striation

[0014] - a defect due to print degradation

[0015] - a skirt rollover defect.

[0016] There is therefore a need to improve the quality, particularly the visual quality, of welds between the component and the tubular body, and an object of the invention is to propose a method and welding means capable of remedying these defects so as to obtain packagings with improved weld characteristics.

[0017] An object of the invention is to provide a welding method that improves the quality of the weld assembly of flexible packaging tubes comprising at least one flexible P4279PC01 / 101-192 spec dpt tubular body and a component that may be, for example, a tube head, an opening / closing system or a closed end such as a bottom. These tubes are intended, particularly though not exclusively, for packaging liquid or viscous products, semi-liquids or solids (for example, in powder form).

[0018] The invention relates to a welding method carried out on an indexed rotary turret, enabling high-throughput manufacture of packaging tubes.

[0019] An aim of the invention is to provide a method that improves the visual quality of the weld joining the component to recyclable tubular bodies referred to as “monomaterial” (i.e. formed essentially from the same material or material family) and / or of reduced wall thickness.

[0020] Another aim of the invention is to provide a method that improves the visual quality of the weld joining the component to tubular bodies comprising recycled and / or bio-based and / or biodegradable materials.

[0021] Another aim of the invention is to provide a method that improves the visual appearance of the weld when the tubular body is printed in the weld zone.

[0022] Another aim of the invention is to provide a method that improves the visual appearance of the weld when the weld is not hidden by a cap.

[0023] Another aim of the invention is to provide a welding method that accommodates tubular bodies which behave differently during welding, these behaviours stemming from the different methods used to manufacture the tubes. In particular, the welding method according to the invention allows assembly of the tubular bodies manufactured by extrusion or by extrusion-labelling (see for example publications WO2015 / 159234 and WO2018 / 051235), or also by injection of resin into a mould. P4279PC01 / 101-192 spec dpt

[0024] In embodiments, the invention provides a welding method that improves the visual appearance of the weld by establishing a controlled thermal gradient through the thickness of the tubular body during the welding operation.

[0025] In embodiments, the invention provides a welding method that improves the visual appearance of the weld by actively cooling the outer surface of the tubular body while heating the interface to be welded.

[0026] In embodiments, the invention provides a welding method that improves the visual appearance of the weld by actively cooling the outer surface of the tubular body during the bringing-together of the zones to be welded.

[0027] In embodiments, the invention provides a welding method that improves the visual appearance of the weld by actively cooling the outer surface of the tubular body to prevent its deformation during pressurizing of the zone to be welded.

[0028] In embodiments, the invention provides a method which, during the pressurizing step of the weld, creates targeted deformation and a flow of material in the weld zone, thereby allowing compression of the weld without degrading the visual appearance of the layer forming the outer surface of the weld. According to the method, at least the layer of the tubular body forming the outer surface does not flow during pressurizing.

[0029] In embodiments of the invention, the weld-compression method creates a flow of molten material having the effect of reducing the thickness of the tubular body at the weld and creating a bead of material at the end of the tubular body, said bead being composed of material of the tubular body located beneath the outer surface.

[0030] In embodiments of the invention, the welding method embeds, at least in part, the bead of material at the end of the weld, thereby improving the continuity of the outer surface of the packaging. Hence, according to embodiments of the P4279PC01 / 101-192 spec dpt invention, at least 60% of the bead is embedded and, preferably at least 80% of the bead is embedded. These values are, of course, indicative and other values are possible within the scope of the present invention.

[0031] In embodiments, the invention relates to a method for manufacturing a tubular packaging by welding the end of a tubular body to a component, said component being, for example, a shoulder, a closure system (such as a cap) or a bottom, said method comprising at least the following steps:

[0032] A. supplying a component;

[0033] B. supplying a tubular body;

[0034] C. heating the interface to be welded of the component and of the tubular body;

[0035] D. positioning the zones to be welded;

[0036] E. pressurizing and cooling the weld; said method being characterized in that, at least during the heating of the interface, the outer face of the zone to be welded of the tubular body is actively cooled in such a manner that a thermal gradient is created through the thickness of the tubular body during step C; the surface layer of the tubular body does not flow during step E and a bead of material originating from the tubular body is formed at the end of the surface layer, said bead being embedded and present at the surface of the weld.

[0037] In embodiments, at least the tubular body is manufactured by extrusion, extrusion-labelling or injection. In embodiments, at least the tubular body may be made from a laminate. In this context, the present invention relates in particular to tubular bodies made from a thin plastic laminate or containing recycled material, or from a cellulose (such as paper) laminate. Depending on the material used, such as recycled material and / or cellulose, the body preferably comprise at least one plastic layer on one side. P4279PC01 / 101-192 spec dpt

[0038] In embodiments, the outer face of the zone to be welded of the tubular body is actively cooled during step D of positioning of the zones to be welded, so as to maintain a thermal gradient through the thickness of the tubular body and avoid the creation of defects in the outer layer of the tubular body.

[0039] In embodiments, the outer face of the zone to be welded of the tubular body is actively cooled during step E of pressurizing of the weld, so as to maintain a thermal gradient through the thickness of the tubular body and avoid deformation of the outer layer of the tubular body.

[0040] In embodiments, the outer face of the zone to be welded of the tubular body is actively cooled after step F of pressurizing of the weld.

[0041] In embodiments, positioning includes folding the heated end of the tubular body against the component by means of a forming surface having a forming angle between 0° and 85°.

[0042] In embodiments, the forming surface has at least one so-called linear portion in which the forming angle is constant and lies between 35° and 85°.

[0043] In embodiments, the linear portion represents at least 5% of the forming surface.

[0044] In embodiments, the invention relates to packaging (for example a flexible packaging) comprising at least one tubular body and a component, said component being, for example, a tube shoulder, a bottom or a closure system (such as a cap), the end of the tubular body being joined by a weld to the periphery of the component, wherein the weld comprises a bead located at the end of an outer layer of the tubular body and said bead being formed by material(s) located beneath said outer layer, and wherein the bead is at least partially embedded.

[0045] The tubular body may be mono-layer or comprise more than one layer. According to the principles the present invention, the outer face of the tubular body is cooled, P4279PC01 / 101-192 spec dpt the meaning that it is an outer layer of the tubular body that is cooled (when the tubular body comprises at least two layers) or it is the outer surface of the monolayer forming the tubular body, the aim being to avoid a deformation of said outer layer or surface as explained hereunder.

[0046] In embodiments, the bead may be made by material from the tubular body and / or by material from the component.

[0047] In embodiments, at least the tubular body is formed by extrusion, extrusionlabelling or injection. In embodiments, at least the tubular body is be made from a laminate as defined herein.

[0048] In embodiments, more than 60% of the thickness of the bead is embedded.

[0049] In embodiments, the thickness of the tubular body is locally compressed at the weld by at least 1%, and preferably at least 5%.

[0050] In embodiments, the outer surface of the weld comprises a variable welding angle, the welding angle being observed in a plane containing the axis of the tubular body, said welding angle being defined as the angle between the axis of the tubular body and the tangent to the outer surface of the weld.

[0051] In embodiments, the welding angle lies between 0° and about 85°.

[0052] In embodiments, the outer surface of the weld has at least one so-called linear portion in which the welding angle is constant and lies between 35° and 85°.

[0053] In embodiments, the linear surface represents at least 5% of the welded surface.

[0054] In embodiments, the length of the bead visible at the surface is greater than 1% of the weld length. P4279PC01 / 101-192 spec dpt

[0055] In embodiments, the bead is present at the surface over the entire circumference of the weld.

[0056] In embodiments, the colour of the bead is identical to the colour of the component and / or identical to the colour of the outer layer of the tubular body, so as to make it hard to see with the naked eye.

[0057] In embodiments, the thickness of the tubular body is less than 450 microns.

[0058] In embodiments, the tubular body and / or the component comprises (comprise) recycled and / or biodegradable and / or bio-based material.

[0059] In embodiments, the content of recycled and / or biodegradable and / or bio-based material is greater than 10%, and advantageously greater than 30%.

[0060] In embodiments, the invention relates to a device for implementing the method according to the invention, said device comprising at least means such as a nozzle for applying hot air against the inner wall of the tubular body and the outer wall of the component on the zones to be welded, thereby forming a heated interface, and means, such as a guide cooled by suitable means, for actively cooling the outer wall of the zone to be welded of the tubular body.

[0061] In embodiments, the device comprises means for bringing the zones to be welded into contact.

[0062] In embodiments, said contacting means comprise cooling means.

[0063] In embodiments, the contacting means comprise at least a forming ring with a forming surface and a linear forming surface.

[0064] In embodiments, the device comprises means for pressurizing the weld. P4279PC01 / 101-192 spec dpt

[0065] In embodiments, said pressurizing means comprise cooling means.

[0066] BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 illustrates an example of tubular packaging produced according to the invention.

[0068] Figure 2 illustrates an example of an indexed device for assembling a tubular body and a component.

[0069] Figure 3 illustrates an embodiment of a manufacturing method according to the invention.

[0070] Figure 4 illustrates an embodiment of a device allowing a thermal gradient to be created through the thickness of the tubular body during the heating operation of the interface to be welded (step C).

[0071] Figure 5 illustrates an embodiment of a device allowing the heated end of the tubular body to be folded without degrading the outer surface of the weld (step D).

[0072] Figure 6 illustrates the weld between a tubular body and a component according to the invention.

[0073] Figures 7 and 8 illustrate microscope images of welds produced according to the invention.

[0074] DETAILED DESCRIPTION

[0075] 1 : tubular packaging P4279PC01 / 101-192 spec dpt

[0076] 2: tubular body, for example manufactured by extrusion, extrusion-labelling or injection, can be monolayer or multilayer, or may also be made from a laminate as defined herein

[0077] 3: component

[0078] 4: weld

[0079] 5: assembly zone

[0080] 6: indexed turret

[0081] 7: mandrels

[0082] 8: stations

[0083] 9: outer layer of the tubular body

[0084] 10: cooled guide

[0085] 11 : cooling means of the cooled guide

[0086] 12: hot-air nozzle

[0087] 13: hot air

[0088] 14: heated interface of the tubular body

[0089] 14': heated interface of the component

[0090] 15: cooled surface of the tubular body

[0091] 16: heated surface of the tubular body

[0092] 17: step

[0093] 18: forming ring

[0094] 19: cooling means of the forming ring

[0095] 20: linear surface of the weld

[0096] 21 : welded surface

[0097] 22: bead

[0098] 23: thickness of the tubular body in the conical zone

[0099] 24: thickness of the tubular body

[0100] 25: inner layers of the tubular body

[0101] 26: overthickness of the bead

[0102] 27: length of the bead

[0103] 28: axis of the tubular body

[0104] 29: forming angle

[0105] 30: forming surface P4279PC01 / 101-192 spec dpt

[0106] 31 : linear forming surface

[0107] 32: welding angle

[0108] Figure 1 shows an example of a tubular packaging 1 produced according to the invention comprising at least one tubular body 2, at least one end of which is joined by welding to a component 3. The weld is designated by reference number “4” and the axis of the tubular body is designated by reference number “28”.

[0109] Figure 2 shows an example of a device for assembling the tubular body 2 and the component 3. The device comprises, in particular, an indexed turret 6, mandrels 7 and stations 8. Devices of this kind are described, for example, in publications EP 2 021 156 and EP 3 016 790, provided by way of illustration.

[0110] According to embodiments of the invention and the exemplary embodiment illustrated in Figure 3, the method of welding a tubular body to a component comprises at least the following steps:

[0111] A. supplying a component having a surface to be welded formed at least by a step and an inclined linear portion;

[0112] B. supplying a tubular body;

[0113] C. heating the zones to be welded of the component and of the tubular body while actively cooling at least the outer face of the zone to be welded of the tubular body;

[0114] D. positioning the zones to be welded, for example by folding the heated end of the tubular body against the component by means of a forming surface having a reduced coefficient of friction and a forming angle between 0° and 80°; optionally, actively cooling at least the outer face of the zone to be welded of the tubular body;

[0115] E. pressurizing the zones to be welded, in order to compress the zone to be welded of the tubular body while preventing deformation of the outer layer of the tubular body and forming an embedded bead at the welded end of the tubular body; optionally, actively cooling at least the outer face of the weld. P4279PC01 / 101-192 spec dpt

[0116] Preferably, at least the tubular body is manufactured by extrusion, extrusionlabelling or injection. The tubular body may be monolayer or comprise two or more layers. In embodiments, at least the tubular body may be made from a laminate as described herein.

[0117] The optional active-cooling steps mentioned above may be carried out before and / or during and / or after step D (positioning) and step E (pressurizing), for example during indexing, if these steps are performed at different stations.

[0118] In one embodiment, an additional optional active-cooling step (Step F in Figure 3) may be performed after pressurizing. The cooling steps may be carried out with air, for example, or with other means as described in the present application or with equivalent means.

[0119] Finally, the resulting product undergoes other packaging-manufacturing steps, as described for example in publications EP 2 021 156 and EP 3 016 790, provided by way of illustration.

[0120] Step C:

[0121] An illustrative embodiment of the means used to carry out Step C is shown in Figure 4. Figures 4 to 8 depict sections in a plane containing the axis 28 of the tubular body.

[0122] As depicted in this figure, hot-air nozzles 12 are used to apply a hot-air jet 13 against the inner wall of the tubular body 2 and the outer wall of the component 3 in the zones to be welded, thereby forming a heated interface 14.

[0123] According to embodiments of the invention, at least the end to be welded of the tubular body 2 has a thickness greater than that of the step 17 of the component P4279PC01 / 101-192 spec dpt

[0124] 3. Preferably, the ratio between the thickness of the tubular body 2 and that of the step 17 is between 1.01 and 1.2, and more preferably between 1.03 and 1.1.

[0125] According to embodiments of the invention, active cooling in Step C is achieved by contact of the outer surface 15 of the tubular body 2 with a cooled guide 10. The cooled guide 10 is cooled, for example, by a temperature-controlled water circuit 11 .

[0126] According to embodiments of the invention, the actively cooled guide 10 has a thermal conductivity greater than 8 W / (m.°K), and preferably greater than 13.

[0127] According to embodiments of the invention, the distance between the cooling circuit 11 and the surface of the tubular body 2 is less than 20 mm, preferably less than 10 mm and advantageously less than 5 mm.

[0128] According to embodiments of the invention, the surface of the cooled guide 10 in contact with the tubular body 2 has for example a tubular geometry of diameter slightly smaller than that of the tubular body 2.

[0129] According to other embodiments of the invention, the surface of the cooled guide 10 that is in contact with the tubular body 2 has a very slightly conical geometry, thereby increasing the clamping of the end of the tubular body 2 against the cooled guide 10.

[0130] According to embodiments of the invention, the active cooling during Step C delivers a cooling power greater than 50 W, and preferably greater than 200 W.

[0131] According to embodiments of the invention, the cooled area 15 of the tubular body 2 is greater than, or equal to, the heated surface 16 of the tubular body 2. P4279PC01 / 101-192 spec dpt

[0132] According to embodiments of the invention, the ratio of the cooled surface 15 to the heated surface 16 is greater than 1 , preferably greater than 1.2, and advantageously greater than 1.5.

[0133] According to other embodiments of the invention, the outer surface 15 of the tubular body 2 is actively cooled with a gas, preferably with an air jet.

[0134] According to other embodiments of the invention, the active cooling of the outer surface 15 of the tubular body 2 is carried out with a jet of moist air, or a jet of air containing fine suspended water droplets.

[0135] According to embodiments of the invention, the active cooling is regulated so as to be able to adjust the cooling power and ensure consistency over time of the welds produced.

[0136] According to the invention, heating of the interface to be welded of the tubular body 2 (inner face 16) together with active cooling of the outer surface 15 of the tubular body 2 makes it possible to create a controlled and adjustable thermal gradient through the thickness of the tubular body 2.

[0137] According to embodiments of the invention, adjusting the cooling power allows a modification of the thermal gradient through the thickness of the tubular body 2.

[0138] According to embodiments of the invention, at the end of Step C, the temperature difference between the heated inner surface 16 and the cooled outer surface 15 is greater than 100 °C, and preferably greater than 150 °C.

[0139] According to embodiments of the invention, at the end of Step C, the average thermal gradient through the thickness of the heated tubular body is greater than 50 °C / mm, and preferably greater than 100 °C / mm. P4279PC01 / 101-192 spec dpt

[0140] According to embodiments of the invention, at the end of Step C, at least 50% of the thickness of the tubular body 2 is molten, and preferably at least 70% of the thickness of the tubular body 2 is molten.

[0141] The transition from Step C to Step D may be achieved by indexing, i.e. transition from one station to another or within the same station by replacing the required tools. During indexing or tool change, an additional active-cooling step for the end of the tubular body 2 may be added, for example by means of air injection or by other equivalent means.

[0142] Step D:

[0143] An illustrative embodiment of the means used to carry out Step D is shown in Figure 5.

[0144] In embodiments of the invention, the heated end of the tubular body 2 can be actively cooled while the surfaces to be welded of the component 3 and the tubular body 2 are brought into contact, in order to maintain the thermal gradient through the thickness of the heated end.

[0145] According to embodiments of the invention, the geometry of the heated end of the tubular body 2 is modified to allow the surfaces to be welded to be brought into contact, said modification being a reduction in the circumference (for example, the diameter) of the heated end.

[0146] According to embodiments of the invention, the circumference reduction at the heated end of the tubular body 2 is greater than 1%, preferably greater than 2%, and advantageously greater than 3%.

[0147] According to embodiments of the invention, the thermal gradient through the thickness of the tubular body 2 is adjusted in Step D to allow deformation of the P4279PC01 / 101-192 spec dpt tubular body 2 without creating defects and, in particular, without degrading the visual aspect of the outer layer 9.

[0148] According to embodiments of the invention, the temperature of the means 18, 19 ensuring active cooling of the outer layer 9 during Step D is controlled and adjusted. The thermal gradient through the thickness of the end of the tubular body is maintained by avoiding or limiting reheating of the outer layer of the tubular body.

[0149] According to embodiments of the invention, the bringing into contact of the surfaces to be welded is carried out by means of a forming ring 18, the relative movement of which, with respect to the tubular body 2, causes the heated end of the tubular body 2 (interface 14 in Figure 4) to be folded down against the heated surface of the component 3 (interface 14' in Figure 4).

[0150] According to embodiments of the invention, the temperature of the forming ring 18 is regulated to adjust the temperature of the forming surface 30 and optimize sliding thereon.

[0151] According to a preferred embodiment of the invention, the forming ring 18 is regulated by means of a temperature-controlled water circuit 19.

[0152] According to embodiments of the invention, the forming ring 18 has a thermal conductivity coefficient greater than 8 W / (m.°K), and preferably greater than 13 W / (m.°K).

[0153] According to embodiments of the invention, the forming ring 18 presents a forming surface 30 that comes into contact with the heated end of the tubular body 2 during Step D. The forming surface 30 is characterized by a forming angle 29 that is variable; the forming angle 29 is observed in a plane containing the axis 28 of the tubular body; said forming angle 29 being defined as the angle between P4279PC01 / 101-192 spec dpt the axis 28 of the tubular body and the tangent to the forming surface 30, as illustrated in Figure 5.

[0154] According to embodiments of the invention, the forming angle 29 increases continuously as the radius decreases, so as to progressively fold the end of the tubular body 2.

[0155] According to embodiments of the invention, the forming surface 30 has at least one so-called linear portion 31 in which the forming angle is constant and lies between 35° and 90°, preferably between 45° and 85°.

[0156] According to embodiments of the invention, the linear portion represents at least 5% of the forming surface 30, and preferably at least 15% of the forming surface 30.

[0157] According to a preferred embodiment, the relative displacement between the forming ring 18 and the tubular body 2 takes place along the axis 28 of the tubular body 2.

[0158] According to this preferred embodiment, the forming surface 30, in conjunction with the relative displacement, has the effect of folding down the end of the tubular body 2 against the component 3.

[0159] According to this preferred embodiment, the forming angle 29 lies between 0° and 85°, preferably between 5° and 80°, and advantageously between 10° and 75°.

[0160] According to other embodiments, the forming ring 18 has a radial movement with respect to the axis of the tubular body 2. According to this embodiment, the forming ring 18 comprises a plurality of parts being displaced radially. P4279PC01 / 101-192 spec dpt

[0161] According to other embodiments, the relative movement between the tubular body 2 and the forming ring 18 combines an axial movement and a radial movement.

[0162] According to embodiments of the invention, the forming surface 30 has a low coefficient of friction to allow sliding and deformation of the tubular body 2 during Step D.

[0163] According to embodiments of the invention, the forming surface 30 has a coefficient of friction less than 0.15, preferably less than 0.1. The low coefficient of friction and the thermal gradient in the tubular body 2 enable the heated end of the tubular body 2 to deform without generating defects on the outer face of the tubular body 2, in particular when said outer face is decorated (for example with a decorative film).

[0164] According to embodiments of the invention, the forming ring 18 employs the air- cushion air-bearing principle to reduce friction with the tubular body 2. Advantageously, the forming surface 30 has small holes through which pressurized air is supplied to create this air cushion and reduce friction between the tubular body 2 and the forming surface 30.

[0165] Step E:

[0166] According to embodiments of the invention, pressure is applied to the weld so as to compress the tubular body 2 and ensure good cohesion at the welded interface.

[0167] According to embodiments of the invention, the pressurizing step of the weld serves to forms a bead 22 of material at the end of the tubular body 2, the bead 22 being formed by flow of the molten layers of the tubular body 2. P4279PC01 / 101-192 spec dpt

[0168] According to embodiments of the invention, the outer layer 9 of the tubular body 2 does not flow, because it is cooled at least during the heating operation (Step C of the method); consequently, the material forming said layer 9 is not present in the bead 22. Preventing the outer layer 9 from flowing makes it possible for the invention to avoid visual defects at the weld that would otherwise be created by said outer layer 9.

[0169] According to an optional embodiment, the outer layer 9 is actively cooled during the pressurizing step of the weld, so as to maintain the thermal gradient at the end of the tubular body and prevent deformation of the outer layer 9 while the bead is being formed.

[0170] According to a preferred embodiment of the invention, the outer layer 9 does not flow thanks to the thermal gradient present in the tubular body 2 at the time of the pressurizing step.

[0171] According to another embodiment, the outer layer 9 of the tubular body 2 does not flow because it is actively held in place during the pressurizing step E.

[0172] According to another embodiment, the outer layer 9 does not flow due to the thermal gradient present in the tubular body 2 and because it is actively held during the compression step.

[0173] A first embodiment of a means for actively holding the outer layer 9 involves the use of a pressure ring having a surface with a high coefficient of friction greater than 0.5, and preferably greater than 1.

[0174] A second embodiment of a means for actively holding the outer layer 9 involves holding the outer surface 15 of the tubular body 2 by suction (negative pressure). Advantageously, the pressurizing surface has small holes through which a vacuum is applied, in order to lock the outer layer 9 of the tubular body 2 in place. P4279PC01 / 101-192 spec dpt

[0175] According to embodiments of the invention, the portion of the outer layer 9 of the tubular body 2 that does not flow during pressurizing represents less than 50% of the thickness of the tubular body 2, preferably less than 30% of the thickness of the tubular body 2.

[0176] According to embodiments of the invention, the bead 22 makes it possible to ensure that the tubular body 2 has been properly heated during the welding operation.

[0177] According to embodiments of the invention, the bead 22 is partly embedded in the assembly to avoid creating a break in the surface at the end of the weld, as illustrated in Figure 6.

[0178] According to embodiments of the invention, at least 80% of the thickness of the bead 22 is embedded, and preferably at least 90% of the thickness.

[0179] According to embodiments of the invention, the pressurizing step E simultaneously makes it possible to cool the weld, at least in part.

[0180] According to embodiments of the invention, the outer surface 15 of the tubular body 2 is actively cooled during the pressurizing step E.

[0181] According to embodiments of the invention, active cooling during the pressurizing step E delivers a cooling power greater than 50 W, and preferably greater than 100 W.

[0182] According to embodiments of the invention, the thickness of the tubular body 2 is locally compressed by at least 1%, and preferably by at least 5%, at the weld.

[0183] According to a preferred embodiment of the invention, the pressurizing step is performed by means of the forming ring 18 that was used to bring the surfaces to be welded into contact (step D). P4279PC01 / 101-192 spec dpt

[0184] According to another embodiment of the invention, the pressurizing step is carried out by means of a pressure ring, the geometry of the pressure ring optionally differing from that of the forming ring 18.

[0185] According to embodiments of the invention, the outer surface 15 of the tubular body 2 is actively cooled during the pressurizing step E. The active cooling allows the outer layer 9 of the tubular body to be locked during compression of the weld and prevents the appearance of surface defects.

[0186] According to a preferred embodiment of the invention, active cooling during the pressurizing step E is achieved by contact of the outer surface 15 of the tubular body with the forming ring 18. The forming ring 18 is cooled by a temperature- controlled water circuit 19, for example.

[0187] According to a preferred embodiment of the invention, the compressed weld is kept in contact with the pressure ring, in order to cool the weld.

[0188] According to an alternative embodiment, the weld is cooled by forced convection with air.

[0189] In embodiments, the invention relates to packaging comprising at least one flexible tubular body 2 joined by a weld 4 to a component 3, the weld having no outwardly visible cosmetic defects on its outer face. An example of packaging 1 is shown in Figure 1, and a detail of the assembly zone 5 is shown in Figure 6.

[0190] In a preferred embodiment, the tubular body 2 has no side seam, since it is manufactured by extrusion, by extrusion-labelling or also by injection.

[0191] According to embodiments of the invention, the tubular body 2 is decorated in the weld zone with the component 3. P4279PC01 / 101-192 spec dpt

[0192] According to embodiments of the invention, the tubular body 2 is “mono-material” and / or reduced in thickness. Preferably, the thickness of the tubular body 2 is less than 450 microns, and advantageously less than 350 microns.

[0193] According to other embodiments of the invention, the tubular body 2 and / or the component 3 comprises (comprise) recycled and / or biodegradable and / or biobased material. Preferably, in the tubular body 2 the content of recycled and / or biodegradable and / or bio-based material is greater than 10%, and advantageously greater than 30%.

[0194] According to embodiments of the invention, the weld between the component 3 and the tubular body 2 has a bead 22 of material projecting beyond the end of the outer layer 9 of the tubular body 2 and originating in part from layers located beneath said outer layer 9.

[0195] According to embodiments of the invention, the bead 22 is embedded in the weld. Preferably more than 60% of the thickness of the bead 22 is embedded, advantageously more than 80% and ideally more than 95%.

[0196] According to embodiments of the invention, the thickness of the tubular body 2 is locally compressed at the weld by at least 1 %, and preferably at least 5%, in other words the post-compression thickness is 99%, respectively 95%, of the precompression thickness.

[0197] According to embodiments of the invention, the outer surface of the weld is characterized by a variable welding angle 32; the welding angle 32 being observed in a plane containing the axis 28 of the tubular body; said welding angle 32 being defined as the angle between the axis of the tubular body 2 and the tangent to the outer surface of the weld.

[0198] According to embodiments of the invention, the welding angle 32 increases continuously as the radius decreases. P4279PC01 / 101-192 spec dpt

[0199] According to embodiments of the invention, the welding angle 32 is between 0° and 90°, preferably between 5° and 85°, and advantageously between 10° and 80°.

[0200] According to embodiments of the invention, the outer surface of the weld has at least one so-called linear portion 20 in which the welding angle 32 is constant and lies between 35° and 85°, and preferably between 45° and 80°.

[0201] According to embodiments of the invention, the linear surface 20 represents at least 5% of the welded surface 21 , and preferably at least 15%.

[0202] According to embodiments of the invention, the length of the bead 22 visible at the surface 27 is greater than 1% of the weld length 21, and preferably greater than 5%.

[0203] According to embodiments of the invention, the bead 22 is present at the surface over the entire circumference of the weld.

[0204] According to one embodiment of the invention, the colour of the bead 22 is identical to the colour of the component 2, so as to make it hard to see with the naked eye.

[0205] In another embodiment of the invention, the colour of the bead 22 is identical to the colour of the outer layer 9 of the tubular body so as to make it hard to see with the naked eye.

[0206] Figures 7 and 8 show microscope views of welds produced according to the invention.

[0207] Embodiments have been described to provide an overall understanding of the principles of the structure, function, manufacture and use of the systems and P4279PC01 / 101-192 spec dpt methods disclosed in the present application. Several of these embodiments have been illustrated in the appended drawings and described above. The systems and methods specifically described in the present application and shown in the appended drawings are non-limiting embodiments within the scope of the present invention. The features illustrated or described in connection with one embodiment may be combined with the features of other embodiments. Modifications and variants of this kind are intended to fall within the scope of the present invention. A certain number of issues affecting conventional methods and systems are noted herein and the methods and systems described here may address one or more of these issues. Furthermore, while this invention has been described in conjunction with a certain number of embodiments, alternatives, modifications, equivalents and variants that fall within the spirit and scope of the present invention are also covered by the present application.

Claims

P4279PC01 / 101-192 spec dptCLAIMS1. Method for manufacturing a tubular packaging by welding the end of a tubular body to a component, said component being a shoulder, a cap or a bottom, said method comprising at least the following steps:A. supplying a component;B. supplying a tubular body;C. heating the interface of the component and the tubular body to be welded;D. positioning the zones to be welded;E. pressurizing and cooling the weld; said method being characterized in that at least during the heating of the interface, the outer face of the zone to be welded of the tubular body is actively cooled in such a manner that a thermal gradient is created through the thickness of the tubular body during step C; the surface layer of the tubular body does not flow during step E and a bead of material originating from the tubular body is formed at the end of the surface layer, said bead being embedded and present at the surface of the weld.

2. Method according to Claim 1 , wherein at least the tubular body is manufactured by extrusion, extrusion-labelling or injection or is made from a laminate.

3. Method according to Claim 1 or 2, wherein the outer face of the zone to be welded of the tubular body is actively cooled during step D (positioning of the zones to be welded), so as to maintain a thermal gradient through the thickness of the tubular body and avoid the creation of defects in the outer layer of the tubular body.

4. Method according to any one of Claims 1 to 3, wherein the outer face of the zone to be welded of the tubular body is actively cooled during step E (pressurizing of the weld), so as to maintain a thermal gradient through theP4279PC01 / 101-192 spec dpt thickness of the tubular body and avoid deformation of the outer layer of the tubular body.

5. Method according to any one of the preceding claims, wherein the outer face of the zone to be welded of the tubular body is actively cooled after step F (pressurizing of the weld).

6. Method according to any one of the preceding claims, wherein positioning includes folding the heated end of the tubular body against the component by means of a forming surface having a forming angle between 0° and 85°.

7. Method according to any one of the preceding claims, wherein the forming surface has at least one so-called linear portion in which the forming angle is constant and lies between 35° and 85°.

8. Method according to the preceding claim, wherein the linear surface represents at least 5% of the forming surface.

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