DEVICE AND METHOD FOR PRODUCING HOLDING ELEMENTS BY MOULDING

Description

GENERAL TECHNICAL FIELD

[0001] This presentation concerns the field of closure systems, and more specifically concerns hook closure systems as well as the associated manufacturing processes and equipment. STATE OF THE ART

[0002] Conventional methods and apparatus for producing closure systems comprising self-gripping elements such as hooks conventionally use means of extruding plastic material along a continuous profile, then cutting the latter and deforming it along the longitudinal direction in order to form the hooks. For example, document WO 00 / 50208 is known, which presents an example of a device and method for forming a strip of retaining elements. Document US2010 / 0101056 presents a method for ensuring that retaining elements having a flat head are obtained.

[0003] These successive stages involve in particular several heating and cooling stages during the process, which leads to increased complexity and a consequent increase in the dimensions of the equipment required for manufacturing.

[0004] In addition, each cooling step contributes to increasing the device's occupancy time, which is penalizing. In addition, the need for material cooling between the different stages of the process and therefore between the different stations in the installation leads to a slowdown of the production line.

[0005] Furthermore, the cutting stations and stages lead to a significant increase in the dimensions of the equipment, making its installation very complex.

[0006] Furthermore, the various manufacturing processes are commonly limited in terms of the shape of the retaining elements, the shape of the retaining elements being for example determined by structural elements of the associated apparatus which cannot be easily modified by the user without requiring a substantial modification of the apparatus.

[0007] This presentation therefore aims to respond to these different issues. PRESENTATION OF THE EXPOSITION

[0008] This disclosure relates to a method of forming a hook retainer, wherein: a molding strip is provided having an inner face and an outer face, and comprising a plurality of cavities, each cavity defining a rod extending from the outer face towards the inner face, and comprising an end forming a head extending from the rod towards the inner face of the molding strip, the molding strip is positioned on rotational drive means comprising at least two rollers, the inner face of the molding strip being arranged to bear against the drive means, a molding material is distributed on the outer face of the molding strip by a material distribution means arranged opposite the molding strip so as to define an air gap between the material distribution means and the molding strip,the step of distributing the molding material being carried out so as to fill said air gap and the cavities with molding material in order to form a ribbon comprising a base whose thickness is defined by the air gap, and first preforms projecting from said base comprising a stem and a head, the first preforms being formed by the plastic material in the cavities of the molding strip, the ribbon and the first preforms are demolded, the demolded ribbon is introduced into a forming device so as to modify the shape of the head of the preforms by forming.

[0009] According to one example, during the step of demolding the ribbon and the first preforms, the first preforms are plastically deformed so as to obtain second preforms whose shape is distinct from the first preforms, said second preforms then being deformed by the forming device.

[0010] The forming device comprises at least two rotating elements, said rotating elements each having distinct speeds relative to the strip.

[0011] According to one example, the molding material is polypropylene, and wherein during the forming step, at least one forming element of the forming device is maintained at a temperature between 75 and 165°C, in particular around 120°C.

[0012] According to one example, the step of demolding the ribbon and the first preforms results in a change in height of the head and / or the stem, and / or a change in width of the head and / or the stem.

[0013] In one example, the forming device includes an element at room temperature or at an unregulated temperature, and at least one element at a temperature strictly between the heat deflection temperature (HDT) and the melting temperature of the molding material.

[0014] According to one example, the forming step carries out at least one deformation of a portion of the head of each of the second preforms, said at least one deformation tending for each preform, to deform one of the ends of the head of the preform so as to form a rib on the upper face of the head of the preform.

[0015] According to one example, the step of dispensing the molding material is carried out such that the molding material is dispensed when the inner face of the molding strip is in abutment against a driving roller la casting strip.

[0016] According to one example, the step of dispensing the molding material is carried out through a nonwoven sheet disposed on the molding belt, said nonwoven sheet comprising hollowed-out areas allowing the passage of the molding material.

[0017] According to one example, during the step of dispensing the molding material, the air gap between the material dispensing means and the molding belt is between 10 micrometers and 700 micrometers, more particularly between 10 and 500 micrometers, or more precisely between 50 and 100 micrometers.

[0018] The molding material is then typically polypropylene, and the molding material dispensing step is typically carried out at a pressure of between 10 and 100 bars, or between 30 and 50 bars, and at a temperature of between 150 and 300°C.

[0019] The molding belt is then typically driven at a travel speed of between 1 and 500 m / min, more particularly between 5 and 250 m / min.

[0020] In one example, the demolding step is performed when the base of the ribbon is at a temperature below the melting temperature of the molding material, or below the deflection temperature under load of the molding material.

[0021] According to one example, the step of distributing the molding material is carried out so as to form a ribbon extending in a longitudinal direction comprising a base having two edges in the longitudinal direction, one of the edges having hills and valleys, in which the maximum gap between the hills and valleys in a direction transverse to the longitudinal direction is less than 1.0 mm over a length in the longitudinal direction corresponding to 3 consecutive hills.

[0022] According to one example, prior to the demolding step, a layer of non-woven material is applied against the lower face of the base before solidification of said lower face of the base, so as to cause portions of fibers and / or filaments of the layer of non-woven material to penetrate at least partially into the base.

[0023] In one example, during the step of applying the nonwoven against the underside of the base, the layer of nonwoven material is at room temperature or an unregulated temperature, and the temperature of the base results solely from the step of forming the tape.

[0024] In one example, during the step of applying the strip of nonwoven material against the underside of the base, the underside of the base is at a temperature below its melting temperature.

[0025] The present disclosure also relates to an apparatus for implementing a method as defined above, comprising: a molding device, comprising a molding strip mounted on rotational drive means comprising for example at least two rollers), the molding strip comprising an inner face and an outer face, the inner face being mounted to bear against the rotational drive means, the molding strip comprising a plurality of cavities, each cavity defining a rod extending from the outer face towards the inner face, and comprising an end forming a head extending from the rod towards the inner face of the molding strip, a material distribution means arranged opposite the molding device, configured so as to distribute molding material at a point on the molding strip, so as to form a ribbon of preforms comprising a base whose thickness is defined by the air gap, and first preforms projecting from said base comprising a rod and a head, demolding means,configured to demold a ribbon of preforms formed in the molding strip, a forming device, configured to modify the head of the preforms by forming.

[0026] According to one example, the molding strip and the demolding means are configured such that demolding the preform strip causes deformation of the first preforms so as to form second preforms whose shape is distinct from the first preforms.

[0027] According to one example, the apparatus further comprises means for driving a layer of nonwoven material, adapted to apply a nonwoven material against the underside of the base of the strip of retaining elements downstream of the material distribution means.

[0028] The present disclosure also includes an apparatus for forming a hook retaining device, comprising: a molding device, comprising a molding strip mounted on rotational drive means comprising for example at least two rollers, the molding strip comprising an inner face and an outer face, the inner face being mounted to bear against the rotational drive means, the molding strip comprising a plurality of cavities, each cavity defining a rod extending from the outer face towards the inner face, and comprising an end forming a head extending from the rod towards the inner face of the molding strip, a material distribution means arranged opposite the molding device, configured so as to inject molding material at a point on the molding strip, so as to form a ribbon of preforms comprising a base whose thickness is defined by the air gap, and first preforms projecting from said base comprising a rod and a head, demolding means,configured to demold a ribbon of preforms formed in the molding strip, , the molding strip and the demolding means being configured so that the demolding of the preform strip causes deformation of the first preforms so as to form second preforms whose shape is distinct from the first preforms.

[0029] According to one example, the apparatus further comprises a forming device, configured to modify the head of the preforms by forming.

[0030] According to one example, the forming device comprises at least two rotating elements, one of said rotating elements comprising heating means configured to maintain it at a temperature strictly between the deflection temperature under load and the melting temperature of the molding material.

[0031] According to one example, said rotating elements of the forming device each have distinct speeds relative to the molding device.

[0032] According to one example, the forming means are configured so as to produce at least one fold of the head of the preforms, said at least one fold tending to fold at least one end of the head of the preform towards a central portion of the head of the preform.

[0033] According to one example, the forming device comprises a rotating element configured to operate at room temperature or at an unregulated temperature, and at least one rotating element comprising heating means adapted so that said at least one rotating element operates at a temperature strictly between the deflection temperature under load and the melting temperature of the molding material.

[0034] In one example, the rotating elements of the forming device are configured to be rotated at distinct rotational speeds.

[0035] According to one example, the cavities of the molding strips extend in a cavity direction substantially perpendicular to la outer surface of the molding strip, and each define a shank and a head each having rotational symmetry about said cavity direction, the head having a dimension greater than the maximum dimension of the shank measured radially relative to the cavity direction.

[0036] According to one example, the material distribution means is configured to inject molding material at a point on the molding strip when the inner face of the molding strip is in contact with a roller of the rotating drive means.

[0037] According to one example, the air gap between the material distribution means and the molding belt is between 10 microns and 700 microns, more particularly between 20 and 500 microns, or more precisely between 50 and 100 microns.

[0038] According to one example, the means for driving the molding strip in rotation comprise at least two rollers each having a diameter of between 10 and 10,000 times the thickness of the molding strip, in particular between 50 and 5,000 times the thickness of the molding strip, for example between 100 and 250 mm.

[0039] According to one example, the apparatus further comprises means for applying a strip of non-woven material to the molding strip upstream of the material distribution means.

[0040] In one example, the cavities of the molding strip are open.

[0041] According to one example, the apparatus further comprises a scraping device arranged on the internal face of the molding strip, downstream of the material distribution means.

[0042] In one example, the molding strip includes an inner rubber strip forming its inner face, the ends of the molding strip cavities being formed in said inner rubber strip. PRESENTATION OF FIGURES

[0043] Other features, aims and advantages of the present disclosure will emerge from the following description, which is purely illustrative and not limiting, and which must be read in conjunction with the attached drawings, in which: There Figure 1 schematically presents an example of apparatus for the production of a hook retaining device, The figures 2 to 10 present detailed views of the shape of the retaining elements or preforms obtained, The Figure 11 uses the apparatus presented on the Figure 1 , and adds means of shaping the preforms obtained, The Figures 12A to 12E And 13A to 13J are detailed views illustrating the stages of shaping the hooks as well as the shapes of the hooks or preforms obtained, The Figure 14 is a top view of the ribbon thus obtained illustrating the properties of the edges of this ribbon, The figures 15 and 16 represent an example of apparatus for joining a substrate to a ribbon, for example a ribbon comprising a hook retaining device, The Figure 17 schematically presents an example of a product obtained using such equipment, and The figure 18 schematically presents another example of a product that can be obtained using the equipment presented previously.

[0044] Throughout the figures, common elements are identified by identical numerical references. DETAILED DESCRIPTION

[0045] There Figure 1schematically presents an example of apparatus for the production of a hook retaining device.

[0046] The apparatus as shown comprises a molding strip 1 positioned on rotational drive means 2 comprising here two rollers 21 and 22, a material distribution means 3 adapted to carry out an injection of molding material, for example plastic and / or elastic.

[0047] The assembly formed by the molding strip 1 and the rotation drive means 2 thus forms a molding device.

[0048] The illustrated example comprising two rollers 21 and 22 is not limiting, the number and arrangement of the roller(s) may vary in particular in order to adapt to the length of the molding strip 1 and to the different stations of the apparatus. For example, three rollers could be used or even just one such that the molding strip is arranged on the periphery of the single roller. In particular, only one of the two rollers can be driven in rotation by motorized means, for example the roller 21, the other roller 22 being free, that is to say without motorized means, and driven in rotation via the molding strip, itself driven by the roller 21.

[0049] The molding strip 1 as presented comprises an internal face 11 and an external face 12, the internal face 11 being in contact with the rotation drive means 2.

[0050] The material distribution means 3 is arranged so as to inject molding material onto the external face 12 of the molding strip 1.

[0051] More precisely, the material distribution means 3 is arranged opposite the molding strip 1, spaced from the molding strip 1 so as to define an air gap e indicated on the Figure 1 . The limit of the material injected onto the external face 12 of the molding strip 1 is identified by the reference A, corresponding to the rear edge of the material injected onto the molding strip 1 relative to the direction of movement of the molding strip 1.

[0052] The molding strip 1 is provided with a plurality of cavities allowing the production of hooks of the hook retaining device.

[0053] The cavities 13 are each formed so as to define a rod 14 extending from the external face 12 towards the internal face 11 of the molding strip 1 and a head 15 extending between the rod 14 and the internal face 11 of the molding strip 1. In the example illustrated, the heads 15 of the cavities 13 open onto the internal face 11 of the molding strip 1. The cavities 13 are therefore through-holes. Such an embodiment is not limiting, the cavities 13 can also be blind, and therefore not open onto the internal face 11 of the molding strip 1.

[0054] The portions of the cavities 13 forming the rods 14 typically extend in a direction perpendicular to the external face 12 of the molding strip 1. The portions of the cavities 13 forming the rods 14 typically have a rotation geometry around an axis perpendicular to the external face 12 of the molding strip 1, or a geometry having a plane of symmetry extending in a direction parallel to the direction of travel of the molding strip 1 and / or in a direction perpendicular to the direction of travel of the molding strip 1.

[0055] The portions of the cavities 13 forming the rods 14 have, for example, a generally truncated or cylindrical shape of rotation around an axis perpendicular to the external face 12 of the molding strip 1, and having a rounding at the junction with the external face 12 of the molding strip 1.

[0056] The portions of the cavities 13 forming the heads 15 typically extend radially or transversely relative to an axis perpendicular to the external face 12 of the molding strip 1, and may have rotational symmetry around this axis perpendicular to the external face 12 of the molding strip 1. The portions of the cavities 13 forming the heads 15 typically have a substantially truncated or hexahedral shape.

[0057] The portions of the cavities 13 forming the heads 15 may be linear or curved, for example to form curved portions towards the inner face 11 or towards the outer face 12 of the molding strip 1 extending from the portions of the cavities 13 forming the rods 14.

[0058] The portions of the cavities 13 forming the heads 15 may have a constant or variable thickness.

[0059] In the example shown in the figures, the portions of the cavities 13 forming the heads 15 extend radially around the portions of the cavities 13 forming the rods 14, and have a general disc shape, as can be seen in particular in the Figure 2 which will be presented later.

[0060] The molding strip 1 may have on its internal face 11 or on its external face 12 a particular texture such as grooves, a network of grooves or a network of passages forming a vent or spikes, or be substantially smooth.

[0061] The molding strip 1 may be formed by a superposition of several strips, and is therefore not necessarily single-piece or single-material.

[0062] The material distribution means 3 is typically arranged so as to carry out the injection of molding material into the molding strip 1 in a section of the molding strip 1 where the latter is in abutment against a drive roller, in this case the drive roller 21 in the example shown in the Figure 1 The drive roller then forms a bottom for the cavities 13.

[0063] In the case where the injection of molding material is carried out while the molding strip 1 is not bearing against a drive roller, the material distribution means 3 can then comprise a base arranged on the other side of the molding strip 1, so that the internal face 11 of the molding strip 1 is bearing against the base when the injection of material is carried out, the base then forming a bottom for the cavities 13 of the molding strip 1.

[0064] The molding strip 1 typically has a thickness of between 5 and 5000 micrometers, or between 5 and 2000 micrometers, or more precisely between 20 and 800 micrometers, or between 100 and 500 micrometers.

[0065] The casting strip may have, in the longitudinal direction, a length of between 0.5 and 5 m.

[0066] The molding strip can have, in the transverse direction, a width of between 5 and 3,000 mm.

[0067] The rollers 21 and 22 typically each have a diameter of between 10 and 10,000 times the thickness of the molding strip 1, or between 50 and 5,000 times the thickness of the molding strip 1, more precisely a diameter of between 50 and 750 millimeters, or more particularly a diameter of between 100 and 300 millimeters.

[0068] The use of a molding strip 1 associated with drive means 2 compared to the use of conventional forming means such as rollers in which molding cavities are directly made is advantageous for several reasons.

[0069] The use of a molding strip is particularly interesting in terms of modularity. The molding strip can in fact be easily removed and replaced from the drive means, unlike a solid roller for which the disassembly and reassembly operations are particularly complex to carry out. Such an advantage is particularly observed when the two rollers 21 and 22 are fixed to a frame on one and the same side, leaving the end of the other side free for inserting / removing the molding strip. A means for guiding the molding strip can also be used to facilitate its insertion and / or removal.

[0070] Furthermore, the production of a molding strip is greatly simplified compared to the production of a roller comprising molding cavities. Such rollers are in fact typically produced by stacking successive slices, therefore requiring multiple machining operations and causing significant stresses during assembly and at each change of hook reference and have a significant mass requiring these rollers to be held by their two ends, which consequently complicates their replacement. Furthermore, the use of a molding strip coupled with drive means makes it possible to produce a molding device having a significant length while maintaining simple manufacturing and installation, in particular when one of the rollers is mounted mobile in translation so as to modify the center distance between the rollers and thus allow the tension of the molding strip to be adjusted.Conversely, the production of large diameter molding rolls is particularly complex, and leads to molding means having a very high mass, which therefore implies necessary oversizing for the entire installation in order to support such rolls. In addition, the production of such large diameter molding rolls does not allow acceptable dimensional tolerances to be obtained.

[0071] The various stages of forming a hook retaining device using this apparatus are now described with reference to figures 1 to 4 .

[0072] There Figure 2 represents the molding material once injected into the molding strip 1. We represent on the Figure 2 a side view (in section) of the material in the cavities 13 of the molding strip 1.

[0073] As seen on the Figure 2, the molding material enters the molding strip so as to fill the cavity 13, thereby forming a shank and head blank for hooks.

[0074] A layer of molding material is also deposited on the outer face 12 of the molding strip 1 so as to form a base for the retaining device, the thickness of this layer of molding material being determined by the air gap e between the material distribution means 3 and the molding strip 1.

[0075] The air gap e typically has a thickness between 10 and 700 micrometers, or typically between 10 and 500 micrometers, or between 20 and 100 micrometers.

[0076] In the example shown, the cavities 13 of the molding strip 1 are through-cavities. The apparatus may then comprise an element such as a scraper 4 positioned so as to scrape the internal face 11 of the molding strip 1 to remove excess molding material if necessary. Injection means the action of shaping a molding material by molten process, for example, distribution, supply, molding, injection, extrusion.

[0077] The injection of molding material into the molding strip 1 by the material distribution means 3 therefore makes it possible to form a base 51 and a plurality of elements or preforms each comprising a rod 52 and a head 53, the assembly thus forming a ribbon 100. As will be seen later, the elements comprising the rods 52 and the heads 53 are typically first preforms which will then be subjected to a forming step for the production of the hooks.

[0078] A longitudinal direction is defined relative to the direction of movement of the ribbon 100, this longitudinal direction being parallel to the direction of movement of the ribbon 100. This longitudinal direction is commonly referred to as “machine direction” or “MD” according to the English term. The longitudinal direction is designated by the MD axis in the figures.

[0079] A transverse direction, or "cross direction" or "CD" according to the English term, is also defined, corresponding to a direction perpendicular to the longitudinal direction, and extending parallel to a flat face of the ribbon 100. The transverse direction is designated by the CD axis in the figures.

[0080] The base 51 has an upper face 511 and a lower face 512 which are typically substantially parallel, the upper face 511 being the face provided with the hooks and / or preforms.

[0081] The base 51 typically has a thickness of between 10 and 700 micrometers, or typically between 20 and 500 micrometers, or between 50 and 100 micrometers.

[0082] The base 51 typically has a width of between 1 and 3,000 millimeters, or more precisely between 2 and 400 millimeters, or between 3 and 100 millimeters, the width of the base 51 being measured in the transverse direction relative to the longitudinal direction, for example in a direction parallel to the external face 12 of the molding strip 1.

[0083] THE Figures 3, 4 and 5 illustrate three views of the hook preforms thus formed by injecting material into the molding strip 1, respectively in perspective view, in top view and in sectional view.

[0084] It is understood that these are representations of the molding material within the cavities 13, each represented isolated from the molding strip 1 to detail the shape.

[0085] As can be seen in these figures, the hook preforms thus formed, here the first preforms, have a rod 52 of generally cylindrical or conical shape surmounted by a head 53.

[0086] A lower end 521 of the rod 52 is defined, connecting it to the base 51, and an upper end 522 of the rod 52 opposite the lower end 521 of the rod 52.

[0087] The head 53 extends from the upper end 522 of the rod 52.

[0088] In the example shown, the head 53 has a hexagonal shape whose edges form arcs of a circle. The head 53 therefore comprises a plurality of portions extending radially from the upper end 522 of the rod 52. The head 53, and more generally the assembly formed by the head 53 and the rod 52, therefore has rotational symmetry around an axis passing through the center of the rod 52 and the head 53. Several other shapes of head 53 can be envisaged; the example illustrated is solely intended to illustrate one embodiment. The head 53 may in particular have a hexagonal shape.

[0089] The apparatus as presented and the associated method allow operation at high ribbon forming speeds.

[0090] Indeed, conventional production lines for the production of hook retainers operate at reduced forming speeds, these low forming speeds being compensated by widening the formed ribbon. This limitation in terms of forming speed results in particular from the time required for the injected material to solidify.

[0091] The installation and the method as presented, on the contrary, make it possible to form a ribbon with a high forming speed, for example greater than 20 meters per minute, or even greater than 40, 60, 80, 100, 120 or 150 meters per minute, or even between 1 and 500 meters per minute, or even between 5 and 250 meters per minute. The method presented does not require complete cooling of the injected material for the formation of the hooks, and furthermore, the use of a molding strip with low thermal inertia which can have through cavities makes it possible to considerably improve the solidification speed of the ribbon.

[0092] According to one embodiment, the injection of molding material by the material distribution means 3 can be carried out through a sheet of non-woven material arranged on the external face 12 of the molding strip 1.

[0093] A sheet of non-woven material is then placed on the external face 12 of the molding strip 1 upstream of the material distribution means 3. This sheet of non-woven material may have hollowed-out areas facilitating the passage of the molding material, and also areas preventing the passage of the molding material.

[0094] Such an embodiment thus makes it possible to obtain a ribbon having a layer of non-woven material on its upper face, that is to say on its face having the retaining elements, that is to say the hooks. The injection of the molding material directly onto the sheet of non-woven material then makes it possible to ensure strong cohesion of the non-woven material with the base 51.

[0095] Furthermore, by calibrating the distribution of recessed areas facilitating the passage of the molding material and areas preventing the passage of the molding material, a pattern for the distribution of the hooks can be defined.

[0096] The substrate in the calibrated area typically has an air permeability greater than 2000 l / m2 / sec, more particularly, greater than 4000 l / m2 / sec in the hook passage area. This permeability characteristic is either intrinsic to the substrate or related to the substrate by treatment, drilling, punching, needling, suction, embossing or the like. In one example, the substrate may be a non-woven material, for example a printed non-woven material. The permeability of the substrate is for example measured according to ISO 9237 of 1995 with a pressure of 200Pa and circular specimens of 20 cm 2< .

[0097] The grammage of this nonwoven material is typically between 2 g / m 2< and 45 g / m 2< . In the case where the permeability of the nonwoven material is intrinsic, the permeability may be less than 15,000 l / m 2< / sec, or even less than 7,500 l / m 2< / sec. The nonwoven material used is typically a nonwoven with a thickness between 0.10 and 0.8 mm, in particular between 0.20 and 0.60 mm. The thickness of the nonwoven material is measured for example according to the NF EN ISO 9073-2 standard of 1997 using method A for normal nonwovens with a pressure of 0.5 kPa and for a duration of 10 s.

[0098] The nonwoven material may also have locally low mechanical strength or intrinsically low mechanical strength such that the nonwoven material is perforated by the molding material when making the hooks or preforms.

[0099] The material distribution means 3 can be adapted to distribute simultaneously or successively at least two distinct materials, thus making it possible to define two zones made of two distinct materials in the ribbon 100.

[0100] More specifically, the material distribution means 3 can be adapted to simultaneously inject a molding material such as polypropylene for the formation of the base 51 and the hooks, and an elastic material making it possible to form an elastic profile in the extension of the base 51.

[0101] The molding strip 1 can then have shapes adapted for the different zones of the ribbon 100, for example having a portion provided with cavities 13 for the formation of preforms or hooks corresponding to the portion where the molding material is injected, and a portion not having such cavities 13 corresponding to the portion where the elastic material is injected.

[0102] There Figure 6 schematically represents the demolding of the previously formed ribbon 100.

[0103] Due to the geometry of the cavities, it is understood that the heads 53 are necessarily deformed in order to allow their exit from the molding strip 1.

[0104] The portions of the cavities 13 forming the rods 14 and the heads 15 are thus sized so as to allow the heads 53 to pass through the portions of the cavities 13 forming the rods 14 in order to carry out the demolding.

[0105] The demolding therefore causes a deformation of the heads 53, which is shown schematically on the Figure 6 This deformation may be of an elastic and / or plastic nature, and may therefore result in a modification of the heads 53 and the rods 52 in the event of plastic deformation, or the heads 53 and rods 52 may return to their initial shape after demolding in the event of elastic deformation.

[0106] The nature of the deformation depends in particular on the material used, but also on the geometry of the heads 53 and the rods 52.

[0107] To reduce the force exerted on the preforms during demolding, demolding is typically carried out in an area in which the molding strip is not in contact with one of the rollers 21 and 22.

[0108] In the example shown in the Figure 6 , we schematize a deformation of the head 53 which passes from a generally planar shape to a corolla shape, the portions of which extending radially or transversely from the upper end 522 of the stem 52 therefore pass from a substantially planar configuration to a configuration inclined in a direction opposite to the base 51. The perimeter of the free end of the head 53 typically remains unchanged.

[0109] We then represent on the figures 7 to 10 a portion of ribbon 100 thus demolded.

[0110] In the example shown, the demolding of the ribbon 100 has caused a plastic deformation of the head 53, the geometry of which has therefore been modified relative to the shape of the cavity portion 13 forming the head 15.

[0111] There Figure 7 is a perspective view of a portion of ribbon 100 thus demolded, the figure 8 is a top view, and the figures 9 and 10 are two sectional views along two perpendicular planes identified on the Figure 7 .

[0112] As can be seen from the figures, and in particular from the figures 7, 8, 9 and 10 , the head 53 after demolding has an asymmetrical shape; the orientation of the force during demolding in fact causes distinct deformations on the different portions of the head 53. As shown in the Figure 10, the portion of the head 53 positioned at the front (relative to the direction of travel of the molding strip 1) of the preform is here more raised than the portion of the head 53 positioned at the rear (relative to the direction of travel of the molding strip 1) of the preform, that is to say that the inclination of the portion of the head 53 positioned at the front of the preform has been modified by an angle greater than the angle by which the inclination of the portion of the head 53 positioned at the rear of the preform has been modified. Such an embodiment is not limiting, the head 53 can be produced so as to have a symmetrical shape after demolding. This deformation of the head 53 results in the formation of a flared collar around a central portion of the head 53. This collar has variations in thickness, for example a thickness which becomes thinner as it moves away from the rod 52.Compared to the rod 52, the distal end of the collar has a thickness less than the proximal end of the collar. These thickness variations make the mechanical action of folding easier and reduce the thermal inertia necessary for its deformation in a subsequent step, for example during the folding and / or forming described below.

[0113] More particularly, at least a portion of the collar thus formed has, in section view, an angle A of at least 15° between the mean axis of the portion considered of said collar and a plane parallel to that of the base 51. More particularly, this angle is greater than 35°, even more particularly greater than 45°. On the figure 9 , the angle A as represented is substantially equal to 55° and on the Figure 10 , angle A is approximately equal to 80°.

[0114] Due to the formation of the collar, the maximum dimension of the head of the first preform measured in a plane parallel to the plane of the base 51 (which is referred to as the width of the head) is reduced by 10% to 150%, or by 25% to 100% relative to the head width of the second preform and / or the diameter of the stem of the second preform.

[0115] The height of the head of the second preform is increased by 5% to 100%, or by 12% to 50% relative to the height of the head of the first preform, the height being measured along a plane perpendicular to the plane of the base 51. According to one example, the width of the head is reduced by 0.05mm to 0.2mm for a rod diameter of the order of 0.2mm, the rod diameter of the first and second preforms being substantially identical. The height of the head is increased by 0.025mm to 0.1mm for a rod diameter of the order of 0.2mm, the rod diameter of the first and second preforms being substantially identical.

[0116] It is then considered that the step of injecting the molding material into the molding strip 1 forms first preforms for the hooks, each comprising a rod 52 and a head 53 (as shown for example in the figures 2 to 5), and that these first preforms are then plastically deformed during demolding so as to form second preforms whose shape is distinct from the first preforms, as shown for example in the figures 6 to 10 . Plastic deformation is understood to mean a residual or persistent deformation after elongation and relaxation.

[0117] In the example shown in figures 1 , 11 And 15, the demolding is carried out by means of a demolding roller 6, typically configured so as to separate the base 51 of the ribbon 100 from the molding strip 1 under the effect of the tension of the ribbon and its change of direction. The demolding roller may be equipped with a suction means and / or a surface with a high coefficient of friction, such as for example a rubber coating in order to improve the drive and limit slippage. This demolding roller may be motorized and have a tangential speed slightly higher than that of the strip. The separation between the ribbon 100 and the molding strip 1 is identified in the figures by the reference C, this point corresponding for example to the level from which the base 51 of the ribbon 100 is no longer in contact with the molding strip 1.It may be provided that the molding strip 1 engages on the demolding roller 6, that is to say that the demolding roller 6 forms a lever in the molding strip 1 to facilitate the demolding of the preforms and / or hooks.

[0118] The first or second preforms can then be adapted to perform a function of retaining means, or conversely not have such properties.

[0119] Demolding is typically carried out when the base 51 of the strip 100 is at a temperature lower than the melting temperature of the molding material, or lower than the deflection temperature under load of the molding material, for example when the inner face 11 of the molding strip 1 is at a temperature of the order of 45°C and the upper face 511 of the base 51 is at a temperature of the order of 75°C. The deflection temperature under load is commonly referred to by its English term “Heat Deflection Temperature” or “HDT”.

[0120] The demolding step can be followed by a forming step, in which the second preforms are modified in particular at their head 53.

[0121] We represent schematically on the Figure 11 an apparatus for carrying out such a forming step, and on the figures 12 And 13two successive shape modifications that can be made during such a forming step.

[0122] The apparatus shown in the Figure 11 is similar to the one already shown on the Figure 1 , but also includes a forming device 7 positioned downstream of the demolding roller 6.

[0123] The forming device 7 as shown comprises a drive roller 71 and two forming rollers 72 and 73.

[0124] The drive roller 71 has the function of guiding and driving the ribbon 100. The forming rollers 72 and 73 have the function of carrying out a forming action on the rods 52 and / or the heads 53 of the preforms resulting from demolding.

[0125] In the example shown, the forming device 7 comprises two forming rollers 72 and 73, making it possible to carry out two successive forming steps which are described below. The forming device 7 is not limited to such an embodiment, and may comprise a variable number of rollers or more generally of forming means in order to carry out the desired forming steps. By way of example, the forming device 7 may be configured so as to carry out only a single deformation, and then comprise only a single forming roller.

[0126] The forming rollers 72 and 73 are configured to exert a mechanical and / or thermal force on the heads 53 as well as on the rods 52 of the preforms, so as to cause plastic deformation in order to give a final shape to the hooks.

[0127] An example of forming is described below with reference to the figures 12 to 16 .

[0128] After demolding, the ribbon 100 is driven by the drive roller 71 of the forming device 7. The forming rollers 72 and 73 are arranged so as to each define a passage between the forming roller in question and the drive roller 71 allowing the passage of the ribbon 100.

[0129] These passages between the drive roller 71 and the forming rollers 72 and 73 are sized so as to have a dimension less than the height of the ribbon 100, or where appropriate the height of the ribbon 100 and the substrate, so that the forming rollers 72 and 73 exert a force on the preforms.

[0130] In the example shown, the two forming rollers 72 and 73 will allow two successive stages of deformation of the preforms to be carried out.

[0131] The forming rollers 72 and 73 are each driven in rotation at rotation speeds distinct from that of the drive roller 71, and therefore also distinct from the running speed of the ribbon 100.

[0132] Considering the speed of the drive roller 71 as a reference speed, the first forming roller 72 has a tangential speed lower than that of the drive roller 71, for example between 5 and 200% lower than that of the drive roller 71, or between 10 and 80% lower than that of the drive roller 71, and the second forming roller 73 typically has a tangential speed higher than that of the drive roller 71, for example 5 and 200% higher than that of the drive roller 71, or between 10% and 80% higher than that of the drive roller 71.

[0133] In addition, the forming rollers 72 and 73 are each typically maintained at a predetermined temperature depending on the molding material, for example between 75 and 165°C or more particularly substantially equal to 120°C for a ribbon formed from polypropylene, while the drive roller 71 is maintained at ambient temperature or at an unregulated temperature or at a temperature below the deflection temperature under load, for example below 65°C.

[0134] These drive speed and temperature parameters make it possible to cause adhesion and / or friction and / or sliding of the head 53 of the preforms on the forming rollers 72 and 73, thus causing their deformation.

[0135] THE Figures 12a to 12ethus illustrate the deformation of a preform after action of the first forming roller 72. The direction of rotation of the forming roller 72 and the direction of travel of the ribbon 100 are schematically illustrated by arrows. Upstream of the forming roller 72, the preform as considered is that presented previously with reference to figures 7 to 10 .

[0136] We represent on the Figure 12a schematically the approach of the ribbon relative to the forming roller 72.

[0137] We then represent on the Figure 12bschematically the forming action of the forming roller 72 on the preform. As seen in this figure, the forming roller 72 crushes and deforms a portion of the head 53. More precisely, the forming roller 72 comes into contact with a part of the different portions of the head 53 extending from the upper end 522 of the rod 52, and brings them back towards the central region of the head 53. This deformation of the preform causes a partial softening of the portion brought back towards the central region of the head 53 with the material of the central region of the head 53, and also the formation of a substantially flat inclined region on one face of the head 53.

[0138] There Figure 12c schematically represents the preform after action of the forming roller 72. The Figures 12d and 12e present two other views, respectively in perspective and in top view of such a preform thus deformed.

[0139] As seen in this figure, the forming roller 72 has carried out a deformation on a front of the preform, here the front of the preform relative to the direction of travel.

[0140] This deformation results in the formation of a rib extending in a direction substantially transverse to the longitudinal direction of the ribbon 100.

[0141] The deformation action exerted by the forming roller 72 causes a return of a portion of the head 53 of the preform corresponding to the front of the preform in the direction of travel, but this deformation action causes a flattening of the portions of the head of the preform 53 extending in the transverse direction relative to the direction of travel, thus forming fins extending on either side of the rod 52 in the direction transverse to the direction of travel of the ribbon 100. These fins define attachment portions 54 of the head 53, extending radially beyond the rod 52 of the preform, from the upper end 522 of the rod 52.

[0142] The deformation carried out by the forming roller 72 forms a first rib 81 extending at least partially over the attachment portions 54.

[0143] More generally, the deformation carried out by the forming roller 72 results in the formation of a hooking portion 54 and a rib extending at least partially over the hooking portion 54. The rib thus formed extends over the upper face of the head 53, thus providing mechanical reinforcement for the head 53.

[0144] In the case where the head 53 comprises several attachment portions 54, the forming can then result in the formation of a single rib extending continuously between the attachment portions 54, or several separate ribs each extending at least partially over one or more of the attachment portions 54.

[0145] Following this first deformation by the forming roller 72, a second deformation can be carried out by the forming roller 73.

[0146] THE Figures 13a to 13jschematically represent the deformation of the preform by the forming roller 73, and the shape of the hook which results from it. We now speak of a hook once the preforms have been subjected to these forming steps.

[0147] THE Figures 13a and 13b represent the deformation of the preform by the forming roller 73. As seen in these figures, the forming roller 73 is configured to come into contact with a front portion of the preform relative to its direction of movement, and deform the head 53 of the preform.

[0148] The temperature and rotation speed parameters of the forming roller 73 cause adhesion of the material of the head 53 of the preform, making it possible to straighten a portion of the head 53 projecting from the rod 52.

[0149] It is noted in particular that with respect to the ribbon 100, the forming roller 73 has an identical direction of rotation relative to the forming roller 72 described previously, and has a tangential speed greater than the tangential speed of the drive roller 71.

[0150] Due to these characteristics of direction and rotation speed, the forming roller 73 deforms the head 53 of the preform so as to drive the material of the head 53 towards the front of the preform (relative to its direction of movement).

[0151] As a result, the forming roller 72 performs a first deformation of the preform tending to bring the material from the front of the preform towards the central part of the head 53, while the forming roller 73 performs a second deformation of the preform tending to bring the material towards the front of the preform.

[0152] The first rib 81 formed previously is therefore brought back towards the front of the preform, and extends beyond the rod 52 of the preform. The first rib thus modified is identified by the reference 81' in the figures. For the sake of readability, the first rib will be referred to throughout the text by the reference 81. A second substantially transverse rib 82 is formed, also extending between two transverse ends of the hook, here formed by the hooking portions 54.

[0153] As seen on the figures 13c to 13j , the hook thus formed comprises a first rib 81 resulting from both the action of the first forming roller 72 and the action of the second forming roller 73, and a second rib 82 resulting from the action of the second forming roller 73.

[0154] These two ribs 81 and 82 each extend between two opposite ends of the hook in the transverse direction, that is to say between the two hooking portions 54 in the example shown.

[0155] Considering the direction of drive of the ribbon in the installation, a front edge and a rear edge of the hooks are defined. The first rib 81 extends substantially along the front edge of the hooking portions 54, while the second rib 82 extends substantially along the rear edge of the hooking portions 54. The hooking portions 54 thus typically comprise two distinct ribs extending at least partially over the hooking portion considered.

[0156] The hooking portions 54 and the first and second ribs 81 and 82 thus define transverse ends of the hooks having a substantially U-shape with a substantially flat base and the two ribs of which extend in a substantially perpendicular direction.

[0157] The ribs 81 and 82 therefore make it possible to provide mechanical reinforcement for the hooking portions 54, the latter being configured so as to cooperate with complementary elements such as other hooks or loops in order to form a retaining system. Here, the term “mechanical reinforcement” means the fact that the hook is less likely to deform, under the action of the same force, with such a rib or ribs, than a similar hook without such a rib.

[0158] The hooking portions 54 may extend substantially radially relative to the rod 51, or have a free end inclined towards the base 51 as visible for example in the figures 13e , 13i or 13d , which helps improve the hook's holding properties.

[0159] The rib(s) 81 and 82 each extend over only a portion of the head 53. The ribs thus typically extend over only a portion of the periphery of the head 53. The ribs typically have a cumulative length of between 5 and 95% of the length of the periphery of the head 53, or more precisely between 30 and 70% of the length of the periphery of the head 53. The periphery of the head 53 is here considered to be the radial periphery of the head 53 after the step of forming the hooks or during its formation in the molding strip 1.

[0160] In this example, at least one of the ribs 81 and 82 typically has a length greater than the diameter of the rod 52, the diameter being measured in a direction transverse to the longitudinal direction.

[0161] As can be seen from the figures, and more particularly from the figures 13d And 13h, the ribs 81 and 82 each have, when viewed from above the hook, a general inverted V shape (or U or C shape) comprising two branches forming an angle, this angle typically being between 90° and 180°, or more precisely between 110° and 170°, or between 140° and 150°, or substantially equal to 145°. The two branches of the general V shape of the rib converge here towards the front of the hook. This embodiment is only illustrative, and the general V shape can be inverted so that the rib converges towards the rear of the hook, for example by modifying the speed parameters of the forming device 7. The tip of the inverted V shape, or where appropriate the apex of the U or C, can be towards the front in the longitudinal direction.

[0162] The ribs 81 and 82 typically have a symmetry with respect to a plane extending in a longitudinal direction of the base 51, passing through a central axis of the rod 52 of the retaining elements.

[0163] The hooks thus formed typically have a height of between 5 and 5000 micrometers, or between 5 and 2000 micrometers, or more particularly between 20 and 800 micrometers, or more particularly between 100 and 500 micrometers, the height being measured in a direction perpendicular to the upper face 511 of the base 51.

[0164] The head 53 may be heated prior to the forming step so that it is at a temperature between the deflection temperature under load of the molding material and the melting temperature of the molding material, the forming device 7 comprising a rotating element at a temperature, for example, lower than the deflection temperature under load of the molding material.

[0165] As we see in particular on the figures 13f , 13g And 13j , the hook has a substantially flat inclined region on the face of the head arranged at the rear of the hook (relative to the direction of travel of the molding strip 1).

[0166] Another aspect of the device as presented concerns the regularity of the ribbon thus produced.

[0167] The injection of molding material by the material distribution means 3 makes it possible to obtain a ribbon having substantially straight edges in the longitudinal direction from the time the ribbon is produced, without requiring an additional cutting step.

[0168] We represent schematically on the Figure 14 the ribbon 100 as previously described in top view, which ribbon comprises a base and here preforms or hooks. In the example shown in the Figure 14 , the ribbon 100 is shown provided with preforms such as already described in particular with reference to the figures 7 to 10 .

[0169] This figure schematically represents the ribbon 100 obtained following the injection of material into the molding strip 1, this ribbon therefore extending in a longitudinal direction identified by an axis XX on the Figure 14 . It is also represented on the Figure 14the transverse direction, identified by a YY axis. The longitudinal direction identified by the XX axis is here parallel to the machine direction, i.e. the drive direction of the ribbon 100.

[0170] For this ribbon 100, two edges 102 and 104 are defined, each extending in the longitudinal direction, these two edges 102 and 104 defining the two ends of the ribbon 100 in a transverse direction perpendicular to the longitudinal direction.

[0171] The hooks or preforms are generally arranged near the edges 102 and 104. The hooks or preforms are typically arranged at a distance D from the edges 102 and 104 of between 2 and 3 pitches P of hooks, typically equal to 2 or 3 pitches P of hooks, the distance D being measured in the transverse direction relative to the longitudinal direction materialized by the axis XX on the Figure 14. The pitch P between two hooks corresponds to the distance between two successive hooks in the longitudinal direction. In the example shown in the Figure 14 , the hooks or preforms are arranged in columns extending in the longitudinal direction materialized by the XX axis, these columns being repeated identically in the transverse direction. The hooks or preforms can also be arranged in a staggered or “honeycomb” pattern, for example by offsetting the columns of hooks or preforms in the longitudinal direction.

[0172] As shown in the Figure 14, each of the edges 102 and 104 has a succession of hills and valleys, said succession extending in the longitudinal direction and said hills and valleys extending in a plane parallel to that formed by the base 51, these hills and valleys reflecting slight irregularities in the distribution of molding material for the formation of the strip 100, it being understood that a perfectly straight edge is not industrially achievable. The valleys are understood to be the regions of the edges 102 and 104 projecting towards the inside of the strip 100 while the hills are understood to be the regions of the edges 102 and 104 projecting towards the outside of the strip 100. The regularity of the edges 102 and 104 can therefore be evaluated using these successive hills and valleys.

[0173] The edges 102 and 104 have, in sectional view in a direction transverse to the longitudinal direction, a portion of rounded shape. More particularly, the rounded shape is oriented to the lateral exterior of the base. This rounded shape is produced during the formation of the base. In other words, this rounded shape was not obtained by cutting.

[0174] The apparatus and the method as presented previously make it possible to obtain edges 102 and 104 of the ribbon such that for a length L in the longitudinal direction corresponding to three consecutive hills, the maximum gap E between the hills and the valleys in a direction transverse to the longitudinal direction is less than 3.0 mm, or more precisely less than 2.0 mm, or even more precisely less than 1.0 mm, or even between 0.001 mm and 1.0 mm, more particularly between 0.001 mm and 0.5 mm, even more particularly between 0.001 mm and 0.1 mm.

[0175] Such a definition is also applicable for a length corresponding to three consecutive valleys; the maximum difference between the hills and the valleys in a direction transverse to the longitudinal direction is less than 3.0 mm, or more precisely less than 2.0 mm, or even more precisely less than 1.0 mm, or even between 0.001 mm and 1.0 mm, more particularly between 0.001 mm and 0.5 mm, even more particularly between 0.001 mm and 0.1 mm.

[0176] The 3 consecutive hills or valleys are typically over a distance less than the distance corresponding to 15 hook steps, preferably less than a distance of 25 mm.

[0177] Obtaining edges 102 and 104 which can thus be described as “straight” is advantageous in that it makes it possible to avoid a subsequent step of rectification of the edges, for example via a cutting step, such straight edges being perceived by the user as a sign of product quality.

[0178] Furthermore, the apparatus and method used make it possible to obtain such straight edges without requiring the formation of longitudinal excess thicknesses at the edge of the ribbon, such excess thicknesses not being of functional interest. The base 51 of the ribbon 100 can thus be free of an excess thickness extending continuously along its edges, and typically has a substantially constant thickness from one edge to the other. More generally, it is understood that the base 51 of the ribbon can be free of a non-functional excess thickness (the sole function of which would be to improve the regularity of the edges of the ribbon), which is advantageous in terms of production insofar as excess thicknesses lead to excess consumption of material and increase the occupation time of the molds.

[0179] As understood from the preceding description, the straight edges are obtained via the injection of the molding material by the material distribution means 3. The subsequent demolding and forming steps retain these straight edges as described previously, insofar as these steps do not result in the application of forces to the edges of the base 51 of the ribbon 100. The ribbon 100 thus obtained at the end of these different steps therefore has a straight edge as defined previously.

[0180] Furthermore, in the case of simultaneous or successive distribution of at least two distinct materials by the material distribution means 3, the interface between the two materials is then typically produced so as to have a straight demarcation, as described previously with reference to the edges of the base 51 of the ribbon 100. More precisely, in the case of simultaneous or successive distribution of two materials, each material is injected by the material distribution means 3 so as to form straight edges at the two transverse ends of the ribbon of material thus formed. Consequently, the junction between the two materials is a junction between two straight edges as defined previously, and therefore has a profile that is described as straight according to the definition established previously. The distribution means may, for example, comprise two injection or extrusion nozzles.

[0181] The apparatus presented above and the associated method may also have means and a step of associating a substrate with the ribbon.

[0182] Such association of a substrate to a tape comprising gripping elements is typically achieved by means of an adhesive, or via fusion of the base or substrate, as mentioned previously.

[0183] In order to achieve such a bonding of a substrate to the base of the ribbon, the proposed apparatus may comprise substrate drive means, adapted to provide a substrate feed and to apply the substrate against the lower face 512 of the base 51 of the ribbon 100 downstream of the material distribution means 3.

[0184] We represent schematically on the figures 15 and 16 an example of apparatus comprising such means.

[0185] The apparatus as illustrated is similar to that presented previously with reference to the Figure 1 ; the common elements are therefore not described again here.

[0186] As seen on the figures 15 and 16 , the apparatus as presented comprises substrate drive means 9, here consisting of two rollers 91 and 92, configured to provide a substrate feed 200 downstream of the material distribution means 3.

[0187] The substrate 200 is typically a layer of nonwoven material, a plastic film, an elastic film or a composite film, or a thermally consolidated set of fibers and / or filaments. The substrate 200 is, for example, a web of fibers and / or filaments.

[0188] In the example shown on the figures 15 and 16 , the substrate is represented as a layer of non-woven material.

[0189] A nonwoven fabric is a product obtained by forming a web of fibers and / or filaments that have been consolidated. The consolidation may be mechanical, chemical, or thermal and results in the presence of a bond between the fibers and / or filaments. This consolidation may be direct, i.e., made directly between the fibers and / or filaments by welding, or it may be indirect, i.e., through an intermediate layer between the fibers and / or filaments, for example, a layer of glue or a layer of binder. The term nonwoven fabric refers to a ribbon-like structure or web of fibers and / or filaments that are interwoven in a non-uniform, irregular, or random manner. A nonwoven fabric may have a single-layer structure or a multi-layer structure. A nonwoven fabric may also be joined to another material to form a laminate.A nonwoven fabric may be made from various synthetic and / or natural materials. Exemplary natural materials are cellulose fibers, such as cotton, jute, linen and the like and may also include re-processed cellulose fibers, such as rayon or viscose. Natural fibers for a nonwoven material may be prepared using various processes such as carding. Exemplary synthetic materials include, but are not limited to, synthetic thermoplastic polymers, which are known to form fibers that include, but are not limited to, polyolefins, e.g., polyethylene, polypropylene, polybutylene and the like; polyamide, e.g., polyamide 6, polyamide 6.6, polyamide 10, polyamide 12 and the like; polyesters, for example polyethylene terephthalates, polybutylene terephthalates, polylactic acids and the like, polycarbonates, polystyrenes, thermoplastic elastomers, polymeric vinyls, polyurethanes and blends and copolymers thereof. For example, the nonwoven may be a nonwoven of the Spunbond, Spunmelt, carded thermally bonded, SMS, SMMS, SS, SSS, SSMMS, SSMMMS, Air through or other type.

[0190] The substrate is not limited to a nonwoven, and may more generally be a nonwoven, a woven material, a knitted material, or a combination of several of these materials.

[0191] The substrate drive means 9 are configured to supply the apparatus with substrate 200, and to apply this substrate 200 against the lower face 512 of the base 51 of the ribbon 100 downstream of the material distribution means 3. The substrate drive means 9 are configured so that this application is carried out prior to the solidification of the base 51 of the ribbon 100. Thus, this application causes at least partial penetration of the substrate 200 beyond a plane defined by the lower face 512 of the base 51 of the ribbon 100. Reference B is used in the figures to indicate the point of contact between the base 51 of the ribbon 100 and the substrate 200.

[0192] More specifically, the lower face 512 of the base 51 is substantially planar, and defines a plane. The application of the substrate against this face causes penetration of portions of the substrate 200, for example of fibers and / or filaments of the layer of non-woven material in the case where the substrate 200 is a layer of non-woven material within the base 51, thereby passing through the lower face 512 of the base 51. This is thus schematically shown on the Figure 17 an example of a product resulting from this joining between the ribbon 100 and the substrate 200.

[0193] To the extent that such an application is carried out prior to the solidification of the base 51 of the tape 100, it is not necessary to heat the base 51 of the tape 100 and / or the substrate 200 in order to achieve such a bond.

[0194] For example, considering a base 51 made of polypropylene, the application of the substrate against the lower face 512 of the base 51 is typically carried out when the lower face 512 of the base 51 has a temperature between the melting temperature of the material and the Vicat B softening temperature of the material constituting it minus 30°C or between the melting temperature of the material constituting it and the Vicat A softening temperature of the material constituting it. More particularly, when the base comprises a polypropylene-based material, the lower face 512 of the base 51 has a temperature between 75°C and 150°C, typically of the order of 105°C, this temperature typically being measured by means of an infrared or laser camera.The VICAT softening temperature is defined as the temperature obtained using one of the methods described in ISO 306 or ASTM D 1525 with a heating rate of 50°C / h and a standard load of 50N for VICAT B and a standard load of 10N for VICAT A.

[0195] More generally, when applying the substrate 200 against the lower face 512 of the base 51, the lower face 512 of the base 51 is at a temperature lower than its melting temperature, or more particularly lower than the deflection temperature under load of the material forming the base 51, or even substantially equal to the ambient temperature (or to an unregulated temperature), and the temperature of the base 51 comes solely from the step of forming the ribbon 100. Considering the points A, B and C defined previously and visible in particular on the Figure 15, the distance traveled by the base 51 between points A and B is typically between 20.0 mm and 400 mm. Similarly, the distance traveled by the base 51 between points B and C is typically between 400 mm and 1500 mm. The distance traveled by the base 51 between points B and C is typically twice the distance traveled by the base 51 between points A and B.

[0196] The roller 92 is typically configured to pressurize the substrate 200 against the underside 512 of the base 51 to facilitate penetration of the substrate 200 into the base 51.

[0197] The roller 92 may have patterns or reliefs on its surface, so as to promote the penetration of the substrate 200 into the base 51.

[0198] The substrate 200 may be applied uniformly or non-uniformly against the lower face 512 of the base 51.

[0199] The bond made between the substrate 200 and the base 51 of the ribbon 100 can be made uniformly or non-uniformly.

[0200] In the case where the substrate 200 is a set of thermally consolidated fibers and / or filaments, the connection with the base 51 is also achieved by penetration into the base of a portion of the fibers and / or filaments of the substrate 200.

[0201] In the case where the substrate 200 is a set of thermally consolidated fibers and / or filaments, a plastic film, an elastic film or a composite film, the bonding with the base may then result in a shrinkage phenomenon of the ribbon 100 during its cooling, this shrinkage promoting the bonding surface between the substrate and the base of the ribbon. This shrinkage has no impact on the visual appearance for the end user.

[0202] More specifically, it is well known that molded parts exhibit a shrinkage or shrinkage phenomenon during cooling of the material. In the present case, the strip 100 exhibits portions of distinct thicknesses due to the presence of the retaining elements extending from the upper face 511 of the base 51. These zones exhibiting an excess thickness will cause material shrinkage phenomena vertically from the rods 52 of the hooks, thus forming material shrinkage zones 530 in the lower face 512 of the base 51.

[0203] However, since the substrate 200 is applied against the lower face 512 of the base 51 prior to the solidification of the base 51, this removal of material takes place after application of the substrate against the lower face 512 of the base 51. The application under pressure of the substrate 200 against the lower face 512 of the base 51 as well as the fact that the base 51 is not solidified during this application results in adhesion by molecular interdiffusion between the substrate 200 and against the lower face 512 of the base 51. Thus, during the removal of the material from the base 51 during its solidification as mentioned previously, the substrate 200 remains in contact with the lower face 512 of the base 51, and regions of the film forming the substrate 200 therefore match the shape of the material removal zones in the lower face 512 of the base 51. These regions of the film forming the substrate 200 therefore penetrate beyond the plane defined by the lower face 512 of the base 51.Thus, the surface area of the film forming the substrate 200 in contact with the lower face 512 of the base 51 is greater than the projection of the surface area of the film onto a plane defined by the lower face 512 of the base 51, which makes it possible to increase the adhesion between the substrate 200 and the tape 100.

[0204] In the case where the substrate 200 is a layer of non-woven material, the demolding of the hooks is carried out easily even with a non-woven whose grammage is less than 80gsm. For example, the grammage of the non-woven can be between 5gsm and 120gsm, or between 10gsm and 70gsm.

[0205] In the case where the substrate 200 is a layer of non-woven material, the apparatus may comprise a calendering device upstream of the substrate drive means 9, thus making it possible to carry out a calendering step locally or not of the layer of non-woven material prior to its application against the tape 100.

[0206] This method of securing a substrate 200 to a ribbon 100 is particularly advantageous in that it does not cause deformation of the ribbon 100, and therefore advantageously makes it possible to retain the shape of the base 51 obtained during the injection step, and in particular to retain the straight edges that can be obtained via the method and apparatus described previously.

[0207] This method of securing a substrate to a ribbon can be applied to a method of forming a ribbon as described previously, or more generally to any other method of forming a ribbon comprising retaining elements such as hooks.

[0208] The various devices and methods described above can be used independently or in combination.

[0209] As an example, the following is described with reference to the figure 18 a product that can be obtained using the equipment and processes described above.

[0210] There figure 18 thus presents a product 300 comprising a ribbon 100 made of plastic material, the ribbon 100 is formed in one piece with a film of elastic material 310 by extrusion. More particularly, the ribbon 100 made of plastic material is formed in one piece with a film of elastic material 310 by simultaneous or successive extrusions. Here, "successive extrusions" means the fact that the film 310 and / or the ribbon 300 is produced in the continuity of the formation of the ribbon 300 and / or the film 310, or even on the same production line.

[0211] There figure 18 is a sectional view along a plane perpendicular to the longitudinal direction of the formed product 300.

[0212] The ribbon 100 is similar to the ribbon as previously described, and includes a base 51 and hooks extending from the upper face 511 of the base 51.

[0213] The elastic material film 310 was extruded simultaneously, successively or prior to the extrusion of the ribbon 100 by the material distribution means 3, thus defining a connection between the ribbon 100 and the film 310 along one of their transverse ends. The transition between the elastic film 310 and the base 51 of the ribbon 100 is thus typically continuous.

[0214] Thus, the elastic material film 310, the base and the retaining elements of the plastic material ribbon 100 are made from a single piece and produced by extrusion. The numerical reference 320 designates the interface between the elastic material film 310 and the ribbon 100.

[0215] "In one piece" means that the tape and the film are bonded only by simultaneous or successive distributions of material, for example by simultaneous or successive extrusion. In other words, the bond obtained is achieved only by intramolecular diffusion from the tape to the elastic film and / or from the elastic film to the tape.

[0216] This interface 320 can be produced along a plane substantially parallel to the longitudinal direction of the product 300 as shown in the figure 18 , or make an overlap between the elastic film 310 and the tape 100.

[0217] When the hooks and the base are made of the same material, we can see that there is a continuity of material from the base to the hooks and vice versa. In other words, the material forming the hooks and the material forming the base are contiguous.

[0218] For the elastic film 310, an upper face 311 and a lower face 312 are defined. According to the example shown in the figure, the upper face 311 of the elastic film 310 is here in the extension of the upper face 511 of the base 51 of the ribbon 100. According to the example shown in the figure 18 , the lower face 312 of the elastic film 310 is here in the extension of the lower face 512 of the base 51 of the ribbon 100.

[0219] The assembly formed by the elastic film 310 and the tape 100 thus constitutes an intermediate layer, having a lower face and an upper face.

[0220] As seen on the figure 18 , a substrate 200 is secured to the lower face of the intermediate layer, that is to say to the lower face 312 of the elastic film 310 and to the lower face 512 of the base 51 of the ribbon 100.

[0221] The substrate 200 is for example a non-woven material, as described previously.

[0222] The substrate 200 is secured to the intermediate layer by partial encapsulation in said intermediate layer, that is to say by partial encapsulation of the substrate in the base 51 of the ribbon 100 and in the elastic film 310. This securing is carried out via the method and the apparatus already described previously with reference to figures 15 to 17 .

[0223] The product 300 as presented also comprises a support layer 330 secured to the upper face of the intermediate layer. This support layer 330 extends over the upper face 311 of the elastic film 310, and also at least partially over the upper face 511 of the base 51 of the ribbon 100.

[0224] The support layer 330 may be of identical composition to the substrate 200, or of a distinct composition; for example, it may be a layer of non-woven material, a knit or a grid.

[0225] In the example shown, the support layer 330 is secured to the upper face of the intermediate layer by gluing. This is thus schematically shown on the figure 18 a layer of glue 340 extending on the upper face 311 of the elastic film 310 and also partially on the upper face 511 of the base 51 of the tape 100.

[0226] The support layer 330 is then typically secured to the upper face of the intermediate layer after securing the substrate 200 to the lower face of the intermediate layer.

[0227] It is understood that this method of securing is only illustrative, and that any other suitable method can be used to secure the support layer 330 to the upper face of the intermediate layer.

[0228] The support layer 330 may for example be arranged on the molding strip 1 prior to the distribution of material by the material distribution means 3, so that the plastic and elastic material is injected onto the molding strip while the support layer 330 is positioned on the molding strip 1, as mentioned previously.

[0229] The upper face and / or the lower face of the base 51 of the tape 100 and / or the elastic film 310 may be smooth (except for the hooks) or not. They may for example have raised elements, for example transition elements, removed hooks, recesses such as holes, slots, or projections such as spikes, points, domes and / or peaks. These raised elements may have a height that is less than the height of the retaining elements, more particularly less than 40% of the height of the retaining elements, in particular, less than 25% of the height of the retaining elements. Such raised elements may be advantageous in certain applications, for example to define areas having a distinct roughness or a different surface appearance carrying practical and / or aesthetic advantages.

[0230] In the case where the substrate 200 and / or the support layer 330 is a non-woven material, the substrate 200 and / or the support layer 330 may be activated prior to its attachment to the intermediate layer, as indicated previously.

[0231] A plastic material is understood to mean a thermoplastic material, more particularly a polyolefin material based on homopolymer or copolymer.

[0232] For example, the list of plastic materials: LLDPE (Linear Low Density Polyethylene), LDPE (Low Density Polyethylene), m-PE (Metallocene Polyethylene), HDPE (High Density Polyethylene), EVA (Ethylene Vinyl Acetate) and PP (PolyPropylene), comprising a monomodal or multimodal (e.g. bimodal) molecular weight distribution, in particular a composition comprising LLDPE and a plastomer, in particular a polyethylene-based plastomer. Polyamide (PA), polylactic acid (PLA), polyhydroxyalkanoates (PHA), PVOH, PBS could also be used.

[0233] An elastic material is understood to mean a material adapted to be stretched under the effect of a stretching force exerted in the lateral direction and to substantially return to its initial shape and dimensions after release of said stretching force. This is, for example, a material which retains a residual deformation or remanence after elongation and release (residual deformation also called "permanent set" or "SET") of less than 30%, or even less than 20%, or for example less than 5%, of its initial dimension (before elongation) for an elongation of 100% of its initial dimension, at room temperature (23°C). The SET may be measured as indicated in patent application EP1783257, the content of which is incorporated by reference, and in particular paragraphs

[0056] to

[0062] of publication EP1783257A1 which detail an example of SET measurement.

[0234] Examples of elastic materials include: styrene / isoprene (SI), styrene / isoprene / styrene (SIS), styrene / butadiene / styrene (SBS), styrene-ethylene / butylene-styrene (SEBS), styrene-ethylene / propylene-styrene (SEPS) or SIBS copolymers. Blends of these elastomers with each other or with non-elastomers that modify certain characteristics other than elasticity may also be considered. For example, up to 50 percent by weight, but preferably less than 30 percent by weight, of polymer may be added to modify certain characteristics of the base materials (elasticity, heat resistance, processability, UV resistance, coloring, etc.), such as polyvinyl styrenes, polystyrenes or poly a-methyl-styrenes, epoxy polyesters, polyolefins, for example polyethylenes or certain ethylene / vinyl acetates, preferably those of high molecular weight.

[0235] The elastic material may be, in particular, a styrene-isoprene-styrene, available for example from Kraton Polymers, under the name KRATON D (Registered Trademark), or from DEXCO POLYMERS LP under the name VECTOR SBC 4211 (Registered Trademark). TPE (ThermoPlastic Elastomer) materials may also be used, in particular a thermoplastic polyurethane elastomer, in particular PELLETHANE (Registered Trademark) 2102-75A from The Dow Chemical Company. Styrene-butadiene-styrene may also be used, in particular KRATON D-2122 (Registered Trademark) from Kraton Polymers, or VECTOR SBC 4461 (Registered Trademark) from Dexco Polymers LP. Alternatively, a styrene-ethylene / butylene, such as KRATON G-2832 (Registered Trademark) from Kraton Polymers, or a styrene-ethylene-butylene-styrene (SEBS) block copolymer, such as KRATON (Registered Trademark) G2703, may be used.Alternatively, a copolymer of isooctyl acrylate and acrylic acid can be used in monomer ratios of 90 / 10. Alternatively, a polyamide polyester block copolymer PEBAX (Registered Trademark) 2533 from Arkema can be used.

[0236] Other possible materials are polyolefin polymers, mainly ethylene and / or propylene copolymers, with elastomer characteristics, notably derived from metallocene catalysis, such as VISTAMAXX VM-1120 (Registered Trademark), available from Exxon Mobil Chemical, or polymers filled with rubber, such as Santoprene filled with EPDM.

[0237] Materials may also be used to promote the bond between the plastic material and the elastic material. In an alternative embodiment, it could be envisaged that the cavities of the molding strip each comprise a rod which extends between the upper face and the lower face of the molding strip, from one of these faces to the other.

[0238] Various systems and methods compatible with the present disclosure are described in patent applications FR 16 53866, FR 16 53870, FR 16 53872, FR 16 53873, FR 16 53888, FR 16 53894 and FR 16 53897.

Claims

1. A method of forming a retaining device with hooks, wherein: · a molding strip (1) is provided that presents an inside face (11) and an outside face (12), and that has a plurality of cavities (13), each cavity (13) defining a stem (14) extending from the outside face (12) towards the inside face (11) and including an end forming a head (15) that extends from the stem (14) towards the inside face (11) of the molding strip (1); · the molding strip (1) is positioned on rotary drive means (2), the inside face (11) of the molding strip (1) being arranged to bear against the drive means (2) ; · molding material is dispensed against the outside face (12) of the molding strip (1) by material dispenser means (3) arranged facing the molding strip (1) in such a manner as to define a gap between the material dispenser means (3) and the molding strip (1), the step of dispensing the molding material being performed in such a manner as to fill said gap and the cavities (13) with molding material so as to form a tape (100) comprising a base (51) of thickness that is defined by the gap, and first preforms projecting from said base (51) each comprising a stem (52) and a head (53), the first preforms being formed by the plastics material in the cavities (13) of the molding strip (1); · the tape (100) is unmolded; and · the unmolded tape (100) is inserted in a forming device (7) so as to modify the shapes of the heads (53) of the preforms by forming, characterized in that the forming device (7) comprises at least two rotary elements (72, 73), each of said rotary elements having a speed that is different from the drive speed of the tape.

2. A method according to claim 1, wherein said modification of the shapes of the heads (53) of the preforms by forming produces at least one deformation of a portion of the head (53) of each of the preforms, said at least one deformation tending, for each preform, to deform one of the ends of the head (53) of the preform so as to form a rib (81, 82) on the top face of the head (53) of the preform.

3. A method according to either claim 1 or claim 2, wherein during the step of unmolding the tape (100), the first preforms are deformed plastically so as to obtain second preforms of shape that is different from the shape of the first preforms, said second preforms subsequently being deformed by the forming device (7).

4. A method according to any one of claims 1 to 3, wherein the molding material is polypropylene, and wherein during the forming step, at least one forming element (72, 73) of the forming device is maintained at a temperature lying in the range 75°C to 165°C, and in particular close to 120°C.

5. A method according to claim 3, wherein the step of unmolding the tape (100) and the first preforms leads to a change in the height of the head (52) and / or of the stem (53), and / or to a change in the width of the head (52) and / or of the stem (53).

6. A method according to any one of claims 3 to 5, wherein the forming device (7) comprises an element at ambient temperature, and at least one element at a temperature that lies strictly between the heat deflection temperature (HDT) and the melting temperature of the molding material.

7. A method according to claim 3 or according to claim 3 taken in combination with any one of claims 4 to 6, wherein the forming step produces at least one deformation of a portion of the head (53) of each of the second preforms, said at least one deformation tending, for each preform, to deform one of the ends of the head (53) of the preform so as to form a rib (81, 82) on the top face of the head (53) of the preform.

8. A method according to any one of claims 1 to 7, wherein during the step of dispensing the molding material, the gap between the material dispenser means (3) and the molding strip (1) lies in the range 10 µm to 700 µm, more particularly in the range 10 µm to 500 µm, or more precisely in the range 50 µm to 100 µm.

9. A method according to claim 8, wherein the molding material is polypropylene, and the step of dispensing the molding material is performed at a pressure lying in the range 30 bar to 50 bar, and at a temperature lying in the range 150°C to 300°C.

10. A method according to any one of claims 1 to 9, wherein the unmolding step is performed while the base (51) of the tape (100) is at a temperature lower than the melting temperature of the molding material, or lower than the heat deflection temperature of the molding material.

11. A method according to any one of claims 1 to 10, wherein prior to the unmolding step, a layer of nonwoven material (200) is applied against the bottom face (512) of the base (51) before said bottom face (512) of the base (51) has solidified so as to cause portions of the fibers and / or filaments of the layer of nonwoven material (200) to penetrate into the base (51), at least in part.

12. A method according to claim 11, wherein during the step of applying the nonwoven material (200) against the bottom face (512) of the base (51), the layer of nonwoven material (200) is at ambient temperature, and the temperature of the base (51) is the result only of the step of forming the tape (100).

13. Apparatus for performing a method according to any one of claims 1 to 12, comprising: • a molding device, comprising a molding strip (1) mounted on rotary drive means (2), the molding strip (1) having an inside face (11) and an outside face (12), the inside face (11) being mounted to bear against the rotary drive means (2), the molding strip (1) having a plurality of cavities (13), each cavity (13) defining a stem (14) extending from the outside face (12) towards the inside face (11), and including an end forming a head (15) that extends from the stem (14) towards the inside face (11) of the molding strip (1); • material dispenser means (3) arranged facing the molding device (1,2), and configured in such a manner as to dispense molding material at a point of the molding strip (1) so as to form a tape (100) of preforms having a base of thickness (51) defined by the gap, and first preforms each comprising a stem (52) and a head (53) projecting from said base (51); • unmolding means (6) configured to unmold the tape (100) of preforms formed in the molding strip (1); and • a forming device (7), configured to modify the heads (53) of the preforms by forming.

14. Apparatus according to claim 13, wherein said forming device (7) is configured so as to produce at least one deformation of a portion of the head (53) of each of the preforms, said at least one deformation tending, for each preform, to deform one of the ends of the head (53) of the preform so as to form a rib (81, 82) on the top face of the head (53) of the preform.

15. Apparatus according to claim 13 or claim 14, further comprising drive means (9) for driving a layer of nonwoven material (200) and adapted to press a nonwoven material (200) against the bottom face (512) of the base (51) of the tape (100) of retaining elements downstream from the material dispenser means (3).