Elastic Laminate

Abstract

An elastic laminate extending in a first widthwise direction, specifically in the CD, and in a second lengthwise direction, specifically in the MD, comprises at least one nonwoven layer and at least one elastic film secured by a top surface or a bottom surface, respectively, to a bottom surface or a top surface, respectively, of the at least one nonwoven layer; When the laminate is not in a stretched state, the nonwoven layers are characterized in that in a cross-section in a first direction, in particular in a CD cross-section, they comprise inverted U-shaped, in particular Ω-shaped, curved portions separated from each other by an intermediate portion.

Description

[Technical Field]

[0001] The present invention relates to elastic laminates intended for use in the hygiene sector, in particular for diapers or adult incontinence pants, which laminates extend according to a given width corresponding to a CD direction (Cross Direction) and a larger length corresponding to the unwinding direction during the production of the laminate, called MD direction (Machine Direction), and comprise a stack of one nonwoven layer and at least one elastic film extending over a width equal to or less than said given width, in particular two lower and upper nonwoven layers sandwiching the at least one elastic film. These laminates are in particular intended for use in the manufacture of elastic rags carrying hooks and intended to be fixed to the edges of the rear central waist of the diaper and to engage with loop elements originating from the front of the waist, creating a movable and elastically adjustable closure of the diaper. [Background technology]

[0002] A laminate of this kind is known, for example, from document EP-A-1 783 257 in the name of the applicant. Summary of the Invention [Problem to be solved by the invention]

[0003] While this elastic laminate from the prior art has significant advantages over what previously existed, it would be desirable to further improve it, particularly when it is in the form of an elastic rug in the waist of a diaper, to improve its user comfort, particularly the apparent ability for the user to stretch without the impression that the laminate will tear as a result of stretching. It would also be desirable to improve its softness to the touch in the stretched state. [Means for solving the problem]

[0004] The present invention thus relates, according to a first aspect, to an elastic laminate extending in a first direction, specifically the cross-machine direction, CD, and in a second direction, specifically the length-machine direction, MD, - at least one nonwoven layer; - at least one elastic film secured to, by, the lower or upper surface, respectively, of the at least one nonwoven layer; - at least one adhesive layer, in particular a glue, provided between the at least one nonwoven layer and the at least one elastic film, - when the laminate is not in a stretched state, in particular before a first elongation of the laminate in a first direction, in particular before a first elongation during use once incorporated into an absorbent element such as a diaper, the nonwoven layer comprises, in a cross section in the first direction, in particular in the cross section CD, undulations that form inverted U-shaped, in particular Ω-shaped, curved portions separated from each other by intermediate portions, The intermediate portion is in contact with at least one adhesive layer and the curved portion is not in contact with at least one adhesive layer.

[0005] The present invention also relates, according to a first aspect, to an elastic laminate extending in a first direction, specifically CD, which is the cross direction, and in a second direction, specifically MD, which is the length direction, - at least one nonwoven layer; - at least one elastic film secured to and by the lower or upper surface, respectively, of the at least one nonwoven layer; - in elastic laminates, in which at least one nonwoven layer is fixed to at least one elastic film in a fixing zone, in particular by ultrasonic welding, calendering or lamination, in particular hot lamination, - when the laminate is not in a stretched state, in particular before a first elongation of the laminate in a first direction, in particular before a first elongation when incorporated into an absorbent element such as a diaper and in use, the nonwoven layer comprises, in a cross section in the first direction, in particular in the cross section CD, undulations that form inverted U-shaped, in particular Ω-shaped, curved portions separated from each other by intermediate portions, the intermediate portion is in contact with at least one elastic film and the curved portion is not in contact with at least one elastic film.

[0006] Preferably, the undulations extend in the second direction, particularly in the MD, over the entire length of at least one nonwoven layer, in particular over the entire length of the laminate, the length of the laminate being in particular greater than 20 mm, in particular greater than 30 mm, further in particular greater than 40 mm, and further in particular greater than 60 mm.

[0007] Preferably, the nonwoven layer or layers forming the at least one nonwoven layer extend in a first direction, in particular in the CD direction, across the entire nonwoven width, and the elastic film or films forming the at least one elastic film extend across the entire elastic width, the ratio equal to the entire elastic width to the entire nonwoven width being between 0.3 and 0.9, preferably between 0.4 and 0.8.

[0008] Preferably, the curved portions extend in the first direction, in particular the CD direction, across the entire curved portion width, the intermediate portions extend across the entire intermediate portion width, and the ratio equal to the entire curved portion width to the entire nonwoven width is between 0.25 and 0.85, preferably between 0.35 and 0.75.

[0009] Preferably, according to another aspect of the invention which forms an invention in itself, independently of the other aspects of the invention, in particular independently of the first aspect, according to an aspect which can also be implemented in a preferred manner in combination with each of these other aspects, in particular in combination with the first aspect: the laminate has an initial thickness (e0) before its first stretching, and when the laminate is stretched in the first or second direction to the so-called maximum elongation, which is at least equal to 50%, the curve giving the relative loss in thickness [(e0-e(t)) / e0] as a function of the elongation (t) has a maximum value between 5 and 50%, preferably not more than 40%, more preferably less than 35% and in particular less than 30%.

[0010] In accordance with the present invention, for a given initial thickness, the laminate is thicker in a stretched state than prior art laminates, providing a user with an impression of greater sturdiness when the user stretches the laminate, particularly when the laminate forms an elastic lug for closure of the waist of a diaper. The laminate is also easy to manufacture, soft to the touch, and / or has a bulky or voluminous appearance.

[0011] Preferably, the curve giving the relative thickness loss [(e0-e(t)) / e0] as a function of elongation (t) has a maximum value greater than 10%, even more preferably greater than 20%.

[0012] Preferably, the so-called maximum elongation in the first or second direction is between 50% and 100%.

[0013] Initial thickness (e0) minus the thickness of the laminate at maximum elongation (e max ) over the initial thickness (e0), i.e., the ratio [(e0-e max ) / e0] is less than or equal to 55%, in particular less than 40%, in particular less than 35%, and / or greater than 5%, in particular greater than 10%, in particular greater than 20%.

[0014] Preferably, the initial thickness (e0) minus the thickness of the laminate at 100% elongation (e 100 ) over the initial thickness (e0), i.e., the ratio [(e0-e 100 ) / e0] is less than or equal to 55%, in particular less than 40%, in particular less than 35%, and / or greater than 5%, in particular greater than 10%, in particular greater than 20%.

[0015] Preferably, the laminate, proceeding from its initial state before the first stretching, stretches to 100% elongation and then relaxes to the unstretched state (0% elongation), with a thickness (e v ) is greater than the initial thickness (e0), and the ratio [(e v -e0) / e0] is greater than 2%, in particular greater than 5%, more in particular greater than 10%, and preferably less than 70%, in particular less than 50%, more in particular less than 35%.

[0016] Preferably, the laminate, proceeding from a first unstretched state, stretches to 100% elongation and then relaxes to a second unstretched state (0% elongation), with a thickness (e v ) and has a thickness (e v ) minus the thickness of the laminate at 100% elongation (e 100 ) over the thickness, i.e., the ratio (e v )[(e v -e 100 ) / e v ] is 60% or less, particularly less than 50%, particularly less than 40%, and particularly less than 35%.

[0017] According to a preferred embodiment, the at least one film is fixed to the at least one nonwoven layer by the interposition of an adhesive, e.g., glue, along a glue band or bands or lines extending at a distance from each other in a second longitudinal direction, particularly in the MD, and at a constant or variable pitch and / or discontinuity in the MD.

[0018] According to another embodiment, fixing the at least one film to the at least one nonwoven layer is carried out by hot laminating the elastic film to at least one of the two nonwovens, and in some cases by hot laminating the elastic film to two upper and lower nonwovens.

[0019] According to yet another embodiment, the fixing of the at least one film to the at least one nonwoven layer is performed by hot calendering and / or ultrasonic welding.

[0020] Preferably, at least one nonwoven layer comprises continuous filaments.

[0021] Preferably, at least one nonwoven layer comprises crimped filaments.

[0022] Preferably, at least one nonwoven layer comprises a spunbond nonwoven.

[0023] Preferably, at least one nonwoven layer comprises a layer of spunbond (S), in particular a spunbond based on crimped filaments, and a meltblown (M) layer, or a nonwoven obtained by melting a combination of several of these layers (for example SM, SMS, SMMS, SSMMS, SSSMMS, SSSMMSS).

[0024] According to another aspect of the invention, which itself forms an independent invention from, and may advantageously be practiced in combination with, the above aspect(s), the laminate, after first being stretched to 100% elongation, when subsequently relaxed to a second, unstretched state (0% elongation), loses a thickness (e v ) is greater than the initial thickness (e0) before it is stretched for the first time, and the ratio [(e v -e0) / e0] is greater than 2%, in particular greater than 5%, also in particular greater than 10%, in particular greater than 12.5%, even more preferably greater than 15%, and / or is preferably less than 70%, in particular less than 50%, more in particular less than 35%.

[0025] According to this aspect, it is therefore possible to wind a longer, not yet drawn, laminate onto a reel of a certain diameter (at the output of the production line) while still allowing the same quality of laminate to be used, or to wind the same length of not yet drawn laminate onto a reel of a certain diameter while still allowing a better quality of laminate to be used.

[0026] According to yet another aspect of the present invention, which in itself forms an independent invention from the preceding aspects and which may advantageously be implemented in combination with each or several of those aspects, an elastic laminate extending in a width direction (CD) and a length direction (MD) comprises: - at least one nonwoven layer; - at least one elastic film secured to, respectively by, the lower or upper surface of the at least one nonwoven layer, and characterized by:

[0027] A curve giving the force (N) applied to the laminate in the CD direction as a function of stretch (elongation or elongation as a %) during the first stretch has an inflection point separating a first lower curve segment with its concave surface facing downward from a second upper curve segment with its concave surface facing upward, the first lower segment having a lower vertex and the second upper segment having an upper vertex, the portion of the curve between the origin and the lower vertex being the start segment of the curve, and the portion of the curve between the lower vertex and the inflection point being the use segment of the curve. the portion of the curve between the inflection point and the upper vertex is the stop segment of the curve, the X-axis of the start segment extending from 0% to a value between 5% and 20%, for example 10%, the X-axis of the use segment extending to a value between 5% and 20%, for example 10%, to a value between 60% and 80%, for example 70%, while the X-axis of the stop segment extending following the use segment to a value between 80% and 120%, in particular to 100%, as mentioned in the paragraph above.

[0028] According to a preferred embodiment, the laminate is such that, in the unstretched state of the laminate and / or the elastic film, the nonwoven layers alternately comprise, in the cross-section CD, in particular straight or substantially straight, in particular curved, intermediate portions, in particular with their concave side facing upwards, extending in the CD direction and secured to the elastic film, and inverted U-shaped curved portions, in particular Ω-shaped, consisting of two strand portions each proceeding from two successive intermediate portions and meeting at an apex, not secured to the elastic film and remaining at a distance from the elastic film, so as to define an open space between them and the elastic film, the curvature of the curved portions being greater than that of the intermediate portions.

[0029] By only intermittently fastening the nonwoven layer to the elastic film in this manner, a kind of limit is placed on the possible stretching of the laminate, which has the effect of significantly increasing the stretching ability of the elastic film, particularly when the temperature at which the laminate is used, for example in a diaper, rises significantly, for example approaching 30° C. Thus, particularly at this temperature, when a user stretches the laminate in the CD, the moment the inverted U-shaped portion flattens between the two feet parallel to the stretch direction and the fastening portion, the user will feel a kind of stop, and although body temperature will allow the elastic to stretch further, they will be urged not to stretch the laminate any further to the point where the long-term stability of the laminate will be reduced.

[0030] In this way, the laminate is prevented from rapidly deteriorating, particularly when overstretched, for example, by repeated opening and closing, for example, by countering the phenomenon of "neck-down" or contraction of the elastic material that occurs gradually during use of the diaper, in the case of a diaper. Furthermore, a laminate is obtained that is easier to manufacture and has a softer and / or more bulky or voluminous appearance.

[0031] Preferably, the intermediate portions, in particular the straight or substantially straight intermediate portions, in particular when they are curved with their concave surface pointing upwards, each extend over a distance measured in the CD that is less than 10% of the distance measured in the CD between the two intermediate portions originating from the two strand portions of the inverted U-shaped portion, in particular the Ω-shape, and in particular between 10% and 50% of this distance.

[0032] According to yet another aspect of the present invention, which in itself constitutes an invention independent of the above-mentioned aspects and which can advantageously be implemented in combination with each or several of the above-mentioned aspects, the elastic film based on an elastomeric composition is skinless and preferably has sufficient adhesive and / or tackiness to hold the nonwoven fabric in one or more intermediate portions without glue.

[0033] In accordance with yet another aspect of the present invention, the elastic film includes a skin, preferably two skins, which form the outer surface of the elastic film.

[0034] Very preferably, at least one strip or line of adhesive, in particular glue, is located between the elastic film and the respective intermediate portion.

[0035] Preferably, the height (height of the apex) of the inverted U, particularly the Ω shape, is greater than its width (the distance between the two legs of the inverted U-shaped strand).

[0036] In particular, preferably, each inverted U is Ω-shaped and is defined by two left and right strands that start from a respective straight section and meet at the apex of the inverted U, and one of the two left and right strands of at least one of the inverted U-shaped sections, in particular the two left and right strands of at least one inverted U-shaped section, has a respective curved shape in the starting zone proceeding from the starting straight section, with the respective concave surface facing towards the elastic film.

[0037] Preferably, an additional nonwoven layer is provided on the other side of the elastic film, said additional layer being a short-fiber based nonwoven layer consolidated by water jets or heat, in particular a hydrogen-bonded carded nonwoven (spunlace) or a carded thermally bonded nonwoven.

[0038] Preferably, the nonwoven layer has a first basis weight and the additional nonwoven layer has a second basis weight that is different from the first basis weight, in particular greater than the first basis weight, and in some cases the first basis weight and the second basis weight are equal to within 20%.

[0039] In particular, the nonwoven layer has a first apparent basis weight and the additional nonwoven layer has a second apparent basis weight, and in the elastic zone, the first apparent basis weight is greater than the second apparent basis weight, and the apparent basis weight is determined by measuring the change in the product over time in a cross-sectional view along axis CD and multiplying the change in the product over time by the basis weight of the nonwoven in an unstretched and / or unformed state.

[0040] In particular, the nonwoven layer has a first stiffness and the additional nonwoven has a second stiffness that is less than the first stiffness, and in particular, the nonwoven layer has an elongation in CD at 5N less than 70% and the additional nonwoven layer has an elongation in CD at 5N greater than 70%.

[0041] According to one example, the length of the elastic film in a first direction of the laminate, particularly in the CD, is less than the width of the wrap layer or nonwoven layer in the first direction of the laminate, particularly in the CD.

[0042] According to one example, which may or may not be combined with the previous example, the width of the elastic film in the second direction of the laminate, particularly the MD, is equal to or substantially equal to the length of the wrap layer or nonwoven layer in the second direction of the laminate, particularly the MD.

[0043] The present invention also relates to a method for producing a laminate, in particular a laminate according to the invention.

[0044] According to the invention, the method comprises the steps of taking an elastic film and a nonwoven layer, in particular having continuous filaments, in particular spunbond, in particular "crimped" spunbond; shaping the nonwoven layer so as to obtain, in cross section, a continuous inverted U-shaped nonwoven layer separated by intermediate portions, in particular straight or substantially straight, or curved or substantially curved, wave-shaped nonwoven layers with their concave sides pointing upwards, the curved portions having a greater curvature than the intermediate portions, the latter curvature being in particular zero when straight and close to zero when substantially straight; and fixing the wave-shaped nonwoven layer, preferably by the side of the nonwoven layer opposite the crest of the wave, to an elastic film in an unstretched state.

[0045] Preferably, the filaments are oriented in the MD.

[0046] Preferably, to form (shape) the nonwoven layer, the layer is passed between toothed or saw-toothed rollers.

[0047] Preferably, before the corrugated nonwoven layer is fixed to the elastic film, a strip of adhesive, in particular glue, is laid across the entire width of the elastic film, and then the corrugated nonwoven layer is laminated onto the elastic film.

[0048] According to another embodiment, the elastic film is hot extruded between a support roller and a waver through which the upper nonwoven passes.

[0049] The present invention also relates to baby diapers or adult incontinence pants comprising at least one laminate according to the invention, in particular to form hook tabs extending laterally from the rear waist of the diaper or incontinence pants, so that the hooks engage with loops originating from the front of the waist of the diaper in order to close the diaper or incontinence pants.

[0050] The present invention also relates to an elastic laminate with hooks, comprising a laminate according to the present invention and at least one wrap layer with hooks fixed to the laminate, in particular on the top nonwoven layer, preferably in a zone free of waves or inverted U-shapes.

[0051] The present invention also relates to a roller comprising a laminate according to the present invention, said laminate having a length greater than at least 1 meter and rolled according to an axis perpendicular to the axis MD, said laminate comprising two adjacent elastic films.

[0052] The present invention also relates to the use of a laminate according to the first aspect of the invention to obtain an elastic laminate, in particular when in the form of an elastic lug in the waist of a diaper, having the apparent ability to be stretched by the user without the impression that the laminate will break when stretched, in particular a laminate having an initial thickness (e0) before its first stretching, in which, when the laminate is stretched in a first or second direction to a so-called maximum elongation, which is at least equal to 50%, the curve giving the relative loss in thickness [(e0-e(t)) / e0] as a function of elongation (t) has a maximum value between 5 and 50%, preferably not more than 40%, more preferably less than 35% and in particular less than 30%.

[0053] Preferably, the curve giving the relative thickness loss [(e0-e(t)) / e0] as a function of elongation (t) has a maximum value greater than 10%, even more preferably greater than 20%.

[0054] Preferably, the so-called maximum elongation in the first direction or in the second direction is between 50% and 100%.

[0055] Preferably, the initial thickness (e0) minus the thickness of the laminate at maximum elongation (e max ) over the initial thickness (e0), i.e., the ratio [(e0-e max ) / e0] is less than or equal to 55%, in particular less than 40%, in particular less than 35%, and / or greater than 5%, in particular greater than 10%, in particular greater than 20%.

[0056] Preferably, the initial thickness (e0) minus the thickness of the laminate at 100% elongation (e 100 ) over the initial thickness (e0), i.e., the ratio [(e0-e 100 ) / e0] is less than or equal to 55%, in particular less than 40%, in particular less than 35%, and / or greater than 5%, in particular greater than 10%, in particular greater than 20%.

[0057] Preferably, the laminate, proceeding from its initial pre-stretch state to 100% elongation, then relaxes to a non-stretched state (0% elongation), with a thickness (e v ) is greater than the initial thickness (e0), and the ratio [(e v -e0) / e0] is greater than 2%, in particular greater than 5%, more in particular greater than 10% and preferably less than 70%, in particular less than 50%, and more in particular less than 35%.

[0058] Preferably, the laminate, proceeding from a first unstretched state, stretches to 100% elongation and then relaxes to a second unstretched state (0% elongation), with a thickness (e v ) and has a thickness (e v ) minus the thickness of the laminate at 100% elongation (e 100) over the thickness, i.e., the ratio (e v )[(e v -e 100 ) / e v ] is 60% or less, particularly less than 50%, particularly less than 40%, and particularly less than 35%.

[0059] In particular, the laminate according to the invention has a length greater than a width, in particular by a ratio greater than 1.1, in particular greater than 1.25, in particular greater than 2, in particular greater than 50, more in particular greater than 100, and preferably less than 10000, 5000, 2000 or 1000. In particular, the laminate is rolled and / or unrolled, in particular in its length direction.

[0060] By way of example, several embodiments of the present invention will now be described with reference to the drawings. [Brief explanation of the drawings]

[0061] [Figure 1] 1 is a schematic cross-sectional view CD of a preferred embodiment of a laminate according to the present invention.

[0062] [Figure 1A] 3A-3C are schematic cross-sectional views CD of another embodiment of a laminate according to the present invention.

[0063] [Figure 2A] 2A-2C show schematic diagrams of steps during the production of the laminate of FIG. 1; [Figure 2B] The different steps are shown schematically. [Figure 2C] The different steps are shown schematically. [Figure 2D] The different steps are shown schematically. [Figure 2E] The different steps are shown schematically.

[0064] [Figure 3]FIG. 17 is a schematic perspective view of a portion of a "Waver" device intended to form / shape the upper nonwoven by passing it between two toothed rollers, the teeth of the rollers interpenetrating non-contactingly in the CD, said device forming part of the installation shown in FIGS. 13 to 16.

[0065] [Figure 3B] FIG. 4 is a side view of the device of FIG. 3.

[0066] [Figure 4A] 2B shows the tooth profile of two toothed rollers of the equipment in FIG. 3 that can be used to form the upper nonwoven layer of FIG. 2B into a wave shape.

[0067] [Figure 4B] 2B shows another possible tooth profile for the two toothed rollers of the equipment in FIG. 3 that can be used to form the upper nonwoven layer of FIG. 2B into a wave shape.

[0068] [Figure 5] 1 is a table showing the measured thickness of four samples E53-0, E53-1, E53-2 and E53-3 as a function of their stretching (elongation is equal to the ratio of the increase in length to the initial length) for a first example of a laminate according to the invention.

[0069] [Figure 6] Similar to FIG. 5, four tables are illustrated showing the measured thickness of three samples HG1-1, HG1-2 and E46-1 as a function of their elongation (elongation is equal to the ratio of the increase in length to the initial length) for the second, third and fourth examples of laminates according to the invention and for a comparative (or reference) sample of a prior art laminate.

[0070] [Figure 7] FIG. 1 is a perspective view of a tool for supporting and adjusting the stretching of a laminate, used to measure thickness.

[0071] [Figure 8] FIG. 8 is a plan view of the tool of FIG. 7.

[0072] [Figure 9] FIG. 9 is a side view of the tool of FIGS. 7 and 8.

[0073] [Figure 10] FIG. 10 is another side view of the tool of FIGS. 7 to 9.

[0074] [Figure 11] FIG. 11 is a perspective view of an installation for measuring laminate thickness using the stretch support and adjustment tool shown in FIGS. 7 to 10.

[0075] [Figure 12] FIG. 12 is a cross-sectional view of the installation of FIG.

[0076] [Figure 13] 1 is a schematic diagram of an embodiment of a production facility for the laminate of the present invention.

[0077] [Figure 14] FIG. 14 is a schematic diagram of a modified example of the production facility of FIG.

[0078] [Figure 15] FIG. 2 is a schematic diagram of another embodiment of a production facility for the laminate of the present invention.

[0079] [Figure 16] FIG. 2 is a schematic diagram of yet another embodiment of a production facility for the laminates of the present invention.

[0080] [Figure 17] Two curves representing force as a function of elongation (or elongation) are shown, one (solid line) for a laminate according to the invention making it possible to explain the concept of stop and how to determine said stop for a laminate from the curve of force (N) as a function of elongation (%), and the other (solid line with dots) for a prior art laminate.

[0081] [Figure 18A]1 shows the force / elongation curve of a laminate according to embodiment E46-1 of the present invention. [Figure 18B] 1 shows the force / elongation curve of a laminate according to embodiment E53-0 of the present invention. [Figure 18C] 1 shows the force / elongation curve of a laminate according to embodiment HG1-1 of the present invention.

[0082] [Figure 19] FIG. 1 is a perspective view of a diaper including two elastic lugs formed from a laminate according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0083] 1, the laminate comprises, in succession from top to bottom, an upper nonwoven layer 1, two elastic films 2d and 2g on the right and left, respectively, and a lower nonwoven layer 3. The upper nonwoven layer 1 includes undulations.

[0084] The two elastic films 2d, 2g extend in the CD direction over a distance shorter than the distance over which the two nonwoven layers 1 and 3 extend, so that two edge regions and a central region free of elastic films are formed at the left and right edges and the center of the laminate.

[0085] The upper nonwoven layer 1 and the elastic films 2d, 2g are fixed between them by means of an adhesive, in particular a glue strip 4 interposed therebetween.

[0086] Similarly, the lower nonwoven layer 3 and the elastic films 2d, 2g are secured together by adhesive, particularly glue strips or lines 5d, 5g, extending in the MD direction, i.e., the length direction, and spaced apart from each other in the CD direction.

[0087] In the elastic-free areas, the two nonwovens 1 and 3 are directly fixed to each other by right, central and left fields 6d, 7d, 6c, 7c, 6g, 7g, respectively, which extend in the MD direction and have widths substantially equal to the widths of the edge and central regions (i.e., there is no intervening elastic film, only adhesive is present between them).

[0088] In the cross section CD, as shown in FIG. 1 , the undulations of the upper nonwoven layer 1 form a continuous alternating pattern of intermediate portions 9 and inverted U-shaped curved portions 10. The portions 9 extend in the CD direction over respective widths that may be identical for all portions 9. However, these portions may have different widths from portion to portion without departing from the scope of protection of the present invention. Similarly, the inverted U-shaped portions 10 have respective widths (the distance between two consecutive straight portions on the left and right of the inverted U) that may be identical for all inverted U-shaped portions 10, and a U-shape height (the maximum vertical distance between the apex and the elastic film) that is identical for all inverted U-shapes. However, they may have different widths and heights from portion to portion without departing from the scope of protection of the present invention. The intermediate portions 9 may be straight or substantially straight, or may be curved, particularly slightly curved. Whether they are straight or substantially straight, or slightly curved or curved, the portions 9 always have a curvature that is less than the curvature of the curved portions of the inverted U-shape. In the MD direction, the undulations extend continuously over the entire length of the laminate.

[0089] Each inverted U-shaped portion includes two portions in the form of strands, namely a left portion 10g and a right portion 10d, each of which originates at the middle portion 9 and meets at the apex of the inverted U-shaped portion.

[0090] Each of the two left and right strands of the inverted U-shaped portion has a respective curved shape in the starting zone where it proceeds from the straight portion where it originates, with its concave surface facing towards the elastic film.

[0091] The inverted U-shape may have a width (the distance parallel to the CD between the two straight parts where the inverted U starts) between 0.5 mm and 2 mm, and a height between 0.5 mm and 2 mm, in particular between 0.9 mm and 1.8 mm.

[0092] The intermediate portion may have a length in the MD of more than 3 mm, in particular more than 5 mm, in particular more than 10 mm, and / or spanning the entire length in the MD of the laminate and / or spanning the entire length in the MD of the laminate in the form of an elastic lug, in particular less than 100 mm. The intermediate portion may extend continuously or discontinuously in the MD.

[0093] The intermediate portion may have a width between 0.4 mm and 2 mm, in particular between 0.4 mm and 1.9 mm, in particular between 0.5 mm and 1.5 mm, in particular said width being less than 10% of the width of the inverted U-shape, in particular between 10% and 50% of said width, even more preferably between 10% and 30% of said width of the inverted U-shape in the unstretched state.

[0094] As can be seen in Figures 1 and 1A, the two lower and upper nonwoven layers extend across the entire width of the laminate in the CD direction. This width is the entire width of the nonwoven. The two elastic films 2g and 2d each extend across a width that is less than half the width of the laminate. The sum of the two respective widths over which the two films extend represents the total elastic width. Here, the relationship or ratio of the total elastic width to the total nonwoven width is between 0.4 and 0.8, and in particular, is equal to about 0.7 in Figures 1 and 1A. Figures 1 and 1A show an embodiment in which the upper nonwoven 1 has undulations in the cross section, here in the CD, that form an inverted U-shape separated by intermediate portions, e.g., straight portions, while in the longitudinal direction, here in the MD, these undulations extend seamlessly from one end of the laminate to the other. This shaping is performed, in particular, by a device called a "waver" or "tamper," which will be described below. In contrast, in this example, the lower nonwoven fabric 3 is not formed by a "waver" but is merely activated as described below. It is also possible to perform slight activation on a nonwoven fabric formed by a "waver" as needed. Alternatively, the lower nonwoven fabric 3 can also be formed identically to the upper nonwoven fabric 1, and in particular, like the upper nonwoven fabric 1, it can be formed by a "waver" or "tamper" so that it has undulations in the CD cross section that form an inverted U-shaped portion, particularly a linearly separated portion, by a middle portion, while in the MD the undulations extend continuously from one end of the laminate to the other.

[0095] The curved portions 10 of the upper nonwoven extend in the CD direction across the entire curved portion width, and the middle portion 9 extends across the entire middle portion width, and the ratio equal to the entire curved portion width across the entire width of the nonwoven is between 0.25 and 0.85, in particular between 0.35 and 0.75, and in particular equal to about 0.45 in Figures 1 and 1A.

[0096] Figure 1A shows another embodiment in which the continuous glue band 4 of the embodiment of Figure 1 is replaced by bands or lines 4d, 4g extending lengthwise in the MD and spaced apart from each other in the CD, with the glue bands or lines each having a width in the CD that may be the same or may vary from line / band to line.

[0097] The width of the adhesive, in particular the glue line or band, may be between 0.5 mm and 3 mm, or between 10 mm and 80 mm.

[0098] Furthermore, according to an advantageous embodiment, at least one of the glue lines or bands is located between the elastic film 2d, 2g and one of the intermediate portions 9 of the upper nonwoven layer 1 and has a width in the CD direction that is strictly less than the width of said one of the straight portions 9. In particular, some of the glue lines or bands, in particular all of the glue lines or bands, are each located between the elastic film 2d, 2g and a respective one of the intermediate portions 9 of the upper nonwoven layer 1 and each have a width in the CD direction that is strictly less than the width of said respective one of the intermediate portions 9.

[0099] According to another different embodiment, all the lines or bands of glue are each located between the elastic film 2d, 2g and a respective one of the portions 9 of the upper nonwoven layer 1, and each have a width in the CD direction equal to the width of said respective one of the portions 9.

[0100] The upper nonwoven layer 1 is formed from a nonwoven fabric based on continuous filaments, i.e., long filaments, particularly filaments of 120 mm or more. In particular, the nonwoven fabric of the nonwoven layer 1 may be a spunbond or may include a spunbond combined with another nonwoven fabric, such as SM, SMS, etc.

[0101] The upper nonwoven fabric layer 1 is 10 to 30 g / m 2 Between 10 and 22 g / m 2 The film may have a basis weight between .gtoreq. ...

[0102] The bottom nonwoven layer 3 may be made from continuous filaments, but preferably also from any other nonwoven, in particular based on staple fibres, in particular carded materials such as spunlace.

[0103] The lower nonwoven fabric layer 3 is 10 to 30 g / m 2 Between 18 and 25 g / m 2 The film may have a basis weight between .gtoreq. ...

[0104] The thickness of the upper nonwoven layer (measured perpendicular to the straight section in a static state and in fresh air without applying pressure to the nonwoven) may be between 0.5 mm and 2 mm.

[0105] The thickness of the bottom nonwoven layer (measured perpendicular to the straight section in a static state and in fresh air without applying pressure to the nonwoven) may be between 0.1 mm and 0.5 mm.

[0106] FIG. 2A shows diagrammatically an intermediate laminate obtained during a step during the manufacture of the laminate of FIG. 1 in an installation such as that shown in FIG. 13 or FIG.

[0107] The strips of glue 5d, 5g, as well as the fields of glue 7d, 7c and 7g, are made of a nonwoven layer, for example spunlace, 25 g / m 2, intended to form the bottom nonwoven layer 3. 2 Two elastic films 2g, 2d are placed on top to obtain the intermediate laminate of FIG. 2A.

[0108] Alternatively, a precursor nonwoven layer intended to form the upper nonwoven layer was formed by passing it through the equipment shown in Figures 3 and 4 between two rollers 305 and 306, each containing interpenetrating teeth without contact in the CD, to form the nonwoven layer into an accordion shape, i.e., two accordion-like zones 1d and 1g separated by a non-forming central zone 1c (not passing through the teeth). Furthermore, two edge zones extend between the respective edges of the nonwoven layer and the two accordion-like zones, which likewise do not pass through the teeth and are not formed. During passage through equipment with toothed rollers forming a "waver" module, the upper nonwoven layer is obtained in a shape as shown in Figure 2B. Unlike activation modules well known in the art for activating this type of laminate to release the elasticity of the elastic film within the laminate, the waver module forms the product into a wave shape without breaking the product, especially without breaking the nonwoven. In contrast to activation, which aims to achieve the same or larger width at the exit from the activation block, the waver shapes the product so that the width of the nonwoven fabric at the entrance to the waver is wider than the width of the laminate at the exit from the waver. In the formed regions, particularly along or facing the two elastic films, a formed or "wavy" nonwoven fabric with at least one "wavy" zone has a greater fiber mass or fiber weight per unit width of the laminate than in the non-formed regions, e.g., in Figures 1 and 1A, the two lateral end regions lacking elastic film and the central region also lacking elastic film. At the same time, in these formed regions, the fibers and / or filaments that make up the nonwoven fabric have an average diameter that is substantially the same as the average diameter of the fibers and / or filaments in the non-formed regions. In particular, the relative difference between the two average diameters in the forming and non-forming zones is less than 15%, in particular less than 10%, in particular less than 5%, these variations corresponding to the typical variations in diameter encountered for fibers and / or filaments in nonwoven fabrics."Wavy" zones of a nonwoven fabric can be recognized by observing fibers and / or filaments in the zone that are distinct from zones that have undergone an activation operation and that do not have broken fibers and / or filaments, and / or localized microzones that are free of fibers and / or filaments, and / or microzones with large variations in fiber and / or filament diameter. Microzone characteristics should be observed outside of consolidation points of the nonwoven fabric and / or outside of connection points of the nonwoven fabric to itself and / or to an elastic film and / or to another nonwoven fabric, which connection points are formed by the application of pressure and / or temperature to deform the fibers and / or filaments. Here, the diameter of the fibers and / or filaments refers to the circle of the largest dimension that encompasses the cross-section of the fibers and / or filaments and can have a cross-section that is circular or substantially circular, elliptical or substantially elliptical, or of a different shape. The nonwoven fabric layer formed by the "waver" has, in the unstretched state of the laminate, neutral fibers whose developed length in a cross section in a first direction of the laminate, particularly in the CD, is greater than the width of the laminate, particularly at least 10% greater, particularly at least 15% greater, more particularly at least 20% greater, while in a cross section in a second direction of the laminate, particularly in the MD, the nonwoven fabric layer has neutral fibers whose developed length is equal to or substantially equal to the length of the laminate.

[0109] Subsequently, glue strip 4 and glue fields 6d, 6c and 6g are placed on the intermediate laminate of FIG. 2A to obtain the intermediate laminate of FIG. 2C.

[0110] The nonwoven layer of Figure 2B is then laid down by lamination in an unstretched state onto the intermediate laminate of Figure 2 to obtain the laminate of Figure 1. The intermediate laminate of Figure 2C may or may not be activated prior to lamination with the nonwoven layer of Figure 2B, and / or the nonwoven of the intermediate laminate of Figure 2C may be pre-activated.

[0111] FIG. 2E is an illustration of the laminate of FIG. 2A that has undergone a further activation step prior to coating with glue and laminating the shaped nonwoven.

[0112] The laminate of Figure 2D can then be activated by stretching in the CD to release and / or adjust the elasticity of the bottom nonwoven layer and / or the elastic film, which has the effect of expanding the nonwoven by "breaking" or causing the fibers and / or filaments of the nonwoven to lose their cohesion. Following activation, the nonwoven retracts under the effect of the elastic film, resulting in the laminate of Figure 1. Advantageously, the nonwoven of Figure 2B can be activated prior to the step of forming it into waves.

[0113] According to a variant, it is also possible to carry out activation of the bottom nonwoven layer after the formation of the laminate of FIG. 2A, and to obtain the intermediate laminate of FIG. 2D, in which the glue is placed on the nonwoven from FIG. 2B and then the lamination steps are carried out as described for FIGS. 2C and 2D.

[0114] According to the present invention, it is possible to use non-reactive PSA (pressure-sensitive adhesive) type glues, such as H2465 by Bostik, or reactive PU glues, particularly XPU18314 by Bostik. Preferably, these glues have similar chemical properties to the elastomeric film. For example, when one of these glues is analyzed using infrared spectroscopy to identify chemical functions or liquid chromatography to separate and quantify substances, traces of one or more materials of the elastomeric film, preferably one or more components or their derivatives, are identified.

[0115] Preferably, these glues are based on SIS, SBS, SEBS and SEPS, which allow good compatibility with the film due to their similar chemical properties.

[0116] Preferably, the glue layer has a density of 15 g / m 2 Less than 12 g / m 2less than 8 g / m 2 having a basis weight of less than

[0117] In the present invention, nonwoven fabric is intended to mean the product obtained after the formation of a wrap of consolidated fibers and / or filaments. The consolidation may be mechanical, chemical, or thermal, resulting in the presence of bonds between the fibers and / or filaments. This consolidation may be direct, i.e., by welding, between the fibers and / or filaments, or indirect, i.e., by an intermediate layer between the fibers and / or filaments, such as a size or binder layer. The term "nonwoven fabric" refers to a structure in the form of a tape or wrap of unevenly, irregularly, or randomly interwoven fibers and / or filaments. Nonwoven fabrics may be single-layered or multi-layered. Nonwoven fabrics may be made from various synthetic and / or natural materials. Natural materials are, for example, cellulose fibers such as cotton, jute, paper pulp, and linen, and may also include regenerated cellulose fibers such as rayon or viscose (cellulose acetate). Natural fibers for nonwoven fabric materials may be produced using various processes, such as carding. Synthetic materials include, by way of example and not limitation, synthetic thermoplastic polymers, which are known to form fibers and / or filaments, including, but not limited to, polyolefins such as polyethylene, polypropylene, and polybutylene; polyamides such as polyamide 6, polyamide 6.6, polyamide 10, polyamide 11, and polyamide 12; polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polylactic acid (PLA); polycarbonate; polystyrene; thermoplastic elastomers; vinyl polymers; polyurethanes; and blends and copolymers thereof. Some of these materials are bioplastics, such as bio-derived (e.g., bio-PE, PLA, or PHA (polyhydroxyalkanoates)), polyamide 11, viscose (cellulose acetate), and / or biodegradable (e.g., PLA). Generally, fibers and filaments differ primarily in their length and production method.

[0118] "Continuous filaments" means individual elements that are very long compared to their cross-sectional diameter and that can be continuously extruded to directly form a nonwoven wrap and then consolidated by thermal bonding or other means to achieve the desired performance and / or enable its transport. Preferably, continuous filaments have a length greater than 120 mm.

[0119] "Fiber" is understood as a generic term to denote textile materials or textile material elements that have a short length, less than that of a continuous filament, and that can be spun and / or used to form nonwovens. Two types of fibers are distinguished: short fibers formed of discontinuous material with a short length of less than 50 mm (preferably between 25 mm and 50 mm), and long fibers formed discontinuously and with a length of more than 50 mm (preferably between 60 mm and 120 mm).

[0120] Unlike continuous filaments, which are consolidated immediately after extrusion, the fibers are typically oriented and organized into a wrap during a carding step well known to those skilled in the art. This wrap can then be consolidated by thermal bonding or any other means that achieves the desired performance and / or enables its transport.

[0121] According to the present invention, a "film" refers to a sheet- or wrap-type material whose length and width are each much greater than its thickness (for example, by a factor of 10, 50, or even 1000 or more). Typically, the thickness of a film is less than 0.7 mm, in particular less than 0.5 mm, or even thinner. In particular, a string or thread, or a set of strings and / or threads, is not a film.

[0122] Non-limiting examples of elastomeric materials include styrene / isoprene (SI), styrene / isoprene / styrene (SIS), styrene / butadiene / styrene (SBS), styrene-ethylene / butylene-styrene (SEBS), styrene-ethylene / propylene-styrene (SEPS) copolymers, or SIBS. Mixtures of these elastomers with each other or with non-elastomers that modify certain properties other than elasticity are also contemplated. For example, up to 50% by weight, preferably less than 30% by weight, of polymers may be added to modify certain properties of the substrate (elasticity, heat resistance, processability, UV resistance, coloring, etc.), such as polystyrene or poly-α-methyl-styrene, epoxy polyesters, polyolefins, such as polyethylene or some ethylene / vinyl acetates, preferably those with higher molar masses.

[0123] The elastomer material may be, in particular, a styrene-isoprene-styrene, available, for example, from Kraton Polymers under the name KRATON D®, or from Dexco Polymers LP (USA) or TSRC (Europe) under the name VECTOR SBC4211®, VECTOR SBC4111®, and / or VECTOR SBC4411®, or a mixture of at least two of these materials. TPE (thermoplastic elastomer) materials, in particular polyurethane thermoplastic elastomers, may also be used, in particular ESTANE® 2102-75A-TPU from Lubrizol. Styrene-butadiene-styrene, in particular VECTOR SBC4461® from Dexco Polymers, TSRC COMPANY LP, may also be used. Styrene-ethylene / butylene or styrene-ethylene-butylene-styrene (SEBS) copolymer sequences may also be used.

[0124] Although not exhaustive, the list can be supplemented by the use of all hydrogenated polyisoprene polymers such as styrene-ethylene-propylene-styrene (SEPS), styrene-ethylene-propylene-styrene-ethylene-ethylene-propylene (SEPSEP), hydrogenated polybutadiene polymers such as styrene-ethylene-butylene-styrene (SEBS), styrene-ethylene-butylene-styrene-ethylene-ethylene-butylene-ethylene-butylene-butylene (SEBSEB), styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), styrene-isoprene-butadiene-styrene (SIBS), hydrogenated polyisoprene / butadiene polymers such as styrene-ethylene-ethylene-ethylene-propylene-styrene (SEEPS), hydrogenated vinyl-polyisoprene / hydrogenated polyisoprene / polyisoprene / polystyrene triblock polymers such as commercially available HYBRAR 7311 (Kuraray America, Inc., Houston, TX), and combinations thereof.

[0125] Block polymer architectures such as diblock, triblock, multiblock, star, and radial are also contemplated in this disclosure. In some cases, sequenced copolymers of higher molar mass may be desirable. Sequenced copolymers are available from Kraton Polymers U.S. LLC., Houston, Texas, for example, under the designations Kraton D1184, Kraton FG1901, and Kraton FG1924, and from Kuraray under the designation Septon 8007. Dynasol is another possible source of these polymers.

[0126] Isooctyl acrylate and acrylic acid copolymers, which are thermoplastics that have physical crosslinks in the absence of a crosslinking agent, can also be used in a 90 / 10 monomer ratio.

[0127] Other possible materials are polyolefin polymers with elastomeric properties, primarily ethylene and / or propylene copolymers, especially those derived from metallocene catalysts, such as VISTAMAXX VM-1120® available from ExxonMobil Chemical Company, or indeed rubber-filled polymers.

[0128] Examples of polyolefin-based thermoplastic elastomers that can be used in the elastomeric film layer include, among others, crystalline polyolefins, such as homopolymers or copolymers of α-olefins having 1 to 20 carbon atoms and 1 to 12 carbon atoms.

[0129] The homopolymers and copolymers described below are examples of crystalline polyolefins.

[0130] (1) Ethylene homopolymers. Ethylene homopolymers may be made by either a low-pressure process or a high-pressure process.

[0131] (2) Ethylene copolymers and 10 mole percent or less of an α-olefin other than ethylene, or a vinyl monomer, such as the ethylene octene copolymers available under the trademarks Engage 8407 or Engage 8842 (Dow Chemical, Houston, TX).

[0132] (3) Polypropylene copolymers, examples include polypropylene impact copolymer PP7035E4 and polypropylene random copolymer PP9574E6 (Exxon Mobil, Houston, TX, or indeed polypropylene homopolymer).

[0133] (4) Polypropylene random copolymer and 10 mole percent or less of an olefin other than α-olefin-propylene.

[0134] (5) Sequenced polypropylene copolymer and 30 mole % or less of an α-olefin other than propylene.

[0135] (6) Butene-1-butene homopolymer.

[0136] (7) 1-butene random copolymer and 10 mol % or less of an olefin other than α-olefin-1-butene.

[0137] (8) 4-methyl-1-pentene homopolymer, 4-methyl-1-pentene homopolymer.

[0138] (9) 4-methyl-1-pentene random copolymer and 20 mol % or less of an α-olefin other than 4-methyl-1-pentene.

[0139] Alpha-olefins include, for example, ethylene, propylene, butene-1, 4-methyl-1-pentene, 1-hexene, and 1-octene.

[0140] Commercially available polyolefin-based thermoplastic elastomers intended for use in the elastomeric film layer include VISTAMAXX™ (a propylene and / or ethylene-based elastomer available from ExxonMobil Chemical, Houston, Texas), INFUSE™ (an olefin block copolymer available from Dow Chemical Company, Midland, Michigan), VERSIFY™ (a propylene / ethylene elastomer obtained specifically through INSITE technology) such as VERSIFY™ 4200 (Dow Chemical Company, Midland, Michigan), ENGAGE™ (an ethylene octane copolymer available from Dow Chemical Company, Houston, Texas), and NOTIO 0040 and NOTIO 3560 (available from Mitsui Chemical (USA), New York, NY), and Adflex X100G (available from Lyondellbase). The following materials may also be used: - propylene elastomers, in particular the "Vistamaxx" range by EXXON MOBIL with reference numbers 6000 and / or 6102 and / or 6102FL and / or 6202 and / or 6202FL and / or 6502, 7050BF and / or 7810, and / or - olefin block copolymers, in particular the "Infuse" range by DOW CHEMICAL with reference numbers 9000 and / or 9007 and / or 9010 and / or 9077 and / or 9100 and / or 9107, and / or - polyolefin elastomers, in particular the "Engage" range by DOW CHEMICAL with reference numbers 8402 and / or 8401 and / or 8411 and / or 8407 and / or 8137 and / or 8200 and / or 8207, and / or - propylene-ethylene copolymers, in particular the "Versify" range by DOW CHEMICAL with reference numbers 3200 and / or 3300 and / or 3401 and / or 4200.

[0141] In a particularly preferred embodiment, the polyolefin-based thermoplastic elastomer is VISTAMAXX™ 6102FL or VISTAMAXX 7050BF (available from ExxonMobil Chemical, Houston, Texas). A registered trademark reference "™" stands for "Trademark."

[0142] In other cases, the thermoplastic elastomer may be a thermoplastic ester / ether elastomer.

[0143] "Elastomeric material" refers to a material that can be stretched without rupture under the effect of an extensional force applied in a given direction and that can substantially return to its original shape and dimensions after the extensional force is relaxed. This is, for example, a film that, upon elongation of 100% of its initial dimension at ambient temperature (23°C - Celsius), retains a residual deformation or strain (also called "permanent set" or "set") following stretching and relaxation of no more than 30%, preferably no more than 20%, and even more preferably no more than 10% of its initial dimension (before stretching). The elastomeric material may be a thermoplastic elastomeric material, particularly a physically crosslinked or chemically crosslinked thermoplastic elastomeric material as described herein.

[0144] To measure the stiffness of the nonwoven layer, the following test, among others, can be used.

[0145] Stiffness can be measured using a constant extension of the towing rack being extended at a constant rate of, for example, 508 mm / min, involving a computer interface with a 5 N, 10 N, or 100 N load cell (a suitable instrument is MTS Alliance with TestWorks4 software, available from MTS Systems Corp., Eden Prairie, Minnesota). Testing is performed at 23°C + / - 2°C and a relative humidity of approximately 50% to + / - 2%.

[0146] The rack defines a gap between two lateral clamping jaws, made of, for example, stainless steel, and a plunge blade made of a "light" metal such as aluminum, centrally located halfway between the jaws above the gap. The sample is positioned so that the two ends of the area of ​​the nonwoven layer whose central stiffness is desired to be studied are each clamped to one of the jaws, so that the point on the sample where stiffness is desired to be measured is directly under the plunge blade.

[0147] Cut specimens larger than 50 mm wide and 40 mm long to allow testing with a jaw-to-jaw length of 40 mm. If the element does not have enough material for a specimen of this size, use the available dimensions to compare the stiffness of specimens of the same dimensions. The plunge blade descends at a constant speed of 508 mm / min over a vertical distance of 40 mm, and the acquisition frequency is adjusted to 100 Hz.

[0148] The software is programmed to calculate the maximum peak bending force and stiffness (N / m) of the curve generated, which gives the force (N) as a function of elongation (m). Stiffness is calculated as the slope of the bending / extension curve relative to the linear region of the curve, using a minimum line segment of at least 25% of the total peak bending force to calculate the slope.

[0149] 7 to 10 show an example of a tool 100 for supporting and adjusting a laminate sample for the purpose of determining its thickness.

[0150] The tool comprises a rectangular base 101 from which two lower walls 102, 103 project laterally to the left and right, between which two front and rear rails 104, 105 extend in the form of rods. A trolley 106 is mounted so that it can slide along the two rails 104 and 105. Clamping means are provided which make it possible to lock the trolley 106 in a selected position along the rails 104, 105. These means are controlled by a handle 107 which can be manually rotated between a locked position, in which the trolley 106 can no longer slide along the rails, and an unlocked position, in which the trolley 106 can slide along the rails.

[0151] A movable jaw 108 is attached to the top of the trolley 106 and a fixed jaw 109 is attached to the top of the right lateral bottom wall 103 , the clamping of said jaws being controllable by a clamping nut 111 .

[0152] To support a rectangular laminate sample, for example 30 mm x 30 mm, its two opposite edges in the CD direction are each securely held by one of two movable jaws 108 and one fixed jaw 109. The stretch (elongation) intended to be applied to the sample is then adjusted by releasing the handle 107 to thus slide the movable jaw 108. A slide 110 with markers makes it possible to know the value of the elongation depending on the position of the movable jaw.

[0153] To measure the thickness of a sample of laminate S supported and stretched by tool 100 or an equivalent tool, a pressure application and thickness measurement device 200, particularly known as the "Precision Thickness Tester" sold by VVC under the reference D-2005-V, can be used, as shown in Figures 11 and 12.

[0154] The device 200 is a cylindrical tube with a surface area of ​​25 cm 2 that is placed at one end of a cylindrical arm 203 that is vertically movable under the control of electronic control means incorporated in the device. 2 The other end of the arm includes a disk 202 having a circular surface of 25 cm. 2 To perform these measurements, a 15 mm x 15 mm square pallet 201 is used, so the force applied to the sample is 11.1 kPa (11.1 kPa = 1 kPa * (25 cm 2 / 2.25cm 2 )), not 1 kPa. Therefore, once the laminate is clamped between the pallet and the disk, the thickness of the sample can be measured in the area of ​​the surface of the pallet by performing the following steps:

[0155] The "zero" button on the instrument is pressed and the arm moves downward until it comes into direct contact with the 15x15mm pallet (without the sample) to define a value of 0 micrometers.

[0156] Measure the thickness to ensure that a value of 0 micrometers is obtained.

[0157] The thickness is then measured with a larger weight, for example 10%, to ensure that a value of 0 micrometers is obtained.

[0158] Next, 15 x 15 mm (2.25 cm 2 ) Position the sample on top of the pallet (i.e., 11.1 kPa = 1 kPa * (25 cm 2 / 2.25cm 2 )) Position the 15x15mm pallet on the axis of the cylindrical arm.

[0159] Measurements are then taken according to different stretch amounts adjusted, for example, by the support and adjustment tool 100 shown in FIG. 11, or an equivalent tool.

[0160] To obtain a curve showing the relative loss in thickness as a function of elongation, the laminate is stretched to at least four stretch values, e.g., 25%, 50%, 75%, and 100%, and for each stretch value, the thickness, e.g., e, is measured according to the method described above. 25 , e 50 , e 75 and e 100 is measured and a straight line is plotted connecting successive points thus determined to obtain the curve.

[0161] 5 and 6 show thickness measurement data as a function of stretching samples for four examples of laminates according to the invention and one comparative example of a prior art laminate.

[0162] The prior art laminate was made of Pampers® Baby-Dry size 4 TM and an elastic laminate taken from a pack of diapers bearing the trademark "02184499341631" and from a diaper bearing the reference number "02184499 34 16:13 05 / 08 / 20 Made in Germany E". The product comprises an elastic film sandwiched between two nonwoven fabrics, said elastic film being secured to the two nonwoven fabrics in a stretched state by ultrasonic welding.

[0163] In the present invention, the maximum elongation of a laminate means the elongation in the CD direction at which at least one undulation appears in the cross section of the laminate in the MD direction. In particular, in the present invention, the test is not performed beyond 100% elongation. The maximum loss in thickness is taken at 100%. The maximum elongation is between 50% and 100%. If necessary, the maximum loss in thickness is taken at 100% elongation.

[0164] 13 to 16 are diagrammatic views showing a production facility which makes it possible in particular to obtain the laminates of the invention.

[0165] 13, two first lamination rollers 301 and 302 define a lamination gap between which a first nonwoven layer NT1 passes, with a glue line being laid down by foil at a first coating point on the layer, Coating 1. Two elastic films are also passed into the gap, side by side and spaced apart from each other, so that the films are fixed by laminating them to the first nonwoven layer in the lamination gap.

[0166] The intermediate laminate formed of the first nonwoven fabric layer NT1 and the two elastic films is then conveyed towards a second lamination gap formed between two second lamination rollers 303, 304.

[0167] A second coating point, Coating 2, is positioned upstream of the second lamination gap, with a foil ensuring that a line of glue is placed on the intermediate laminate from the elastic film die.

[0168] Also, a second nonwoven layer NT2 passes through the second gap. Upstream of the second gap, the second nonwoven layer passes into a wave-forming gap known as a waver, which is formed by two toothed rollers 305, 306 called waver rollers, the teeth of the rollers interpenetrating without contact in the CD as shown in Figures 3 and 4B, forming the second nonwoven layer into a wave shape, after which the second nonwoven layer is introduced into the second gap to be laminated to an intermediate laminate, thus obtaining a final laminate at the exit from the second gap.

[0169] In the embodiment of Figure 13, a second nonwoven layer is added to the intermediate laminate at the exit from the wave-forming gap before being introduced into the second lamination gap, with the support roller of the two waver rollers contacting one of the two second lamination rollers 303, 304.

[0170] By adjusting the relative positions of the two waver rollers, the shape of the waves can be adjusted, especially in terms of length and height. By adjusting the number of teeth on the two waver rollers, the number of waves can be adjusted.

[0171] The installations of FIGS. 13, 14 and 16 use a waver according to FIG. 4B having the following dimensions: "Pen" is between 0.5 and 3.5 mm, preferably between 1 and 3.1 mm, and particularly about 2.8 mm. "R2" is between 0.1 and 5 degrees, preferably between 0.2 and 4 degrees, and particularly about 0.50 degrees. "P" is between 0.01 and 3 mm, preferably between 0.02 and 1 mm, and particularly about 0.08 mm. "R" is between 0.1 and 5 degrees, preferably between 0.1 and 3 degrees, and particularly about 0.3 degrees. "Ep2" is between 0.3 and 3 mm, preferably between 0.4 and 1 mm, and particularly about 0.68 mm. "PAS" is between 1 and 4 mm, preferably between 1.5 and 3 mm, and particularly about 2.20 mm. "H" is between 1 and 10 mm, preferably between 2 and 5 mm, and particularly about 4 mm. "Ang2" is between 1 and 10 degrees, preferably between 1.5 and 7 degrees, and particularly about 3.9 degrees. "Ep1" is between 0.5 and 6 mm, preferably between 0.7 and 4 mm, in particular about 1.12 mm. "Ang1" is between 0.1 and 2 degrees, preferably between 0.1 and 0.75 degrees, in particular about 0.25 degrees.

[0172] The installation in Figure 14 is substantially identical to that in Figure 13, the difference being the positioning of the support rollers 305 of the two waver rollers, which remain spaced apart from each of the two second laminating rollers 303, 304.

[0173] 15, two laminating rollers 401 and 402 define a laminating gap, between which a first nonwoven layer NT1 having a glue line deposited by foil at a first coating point, Coating 1, is passed, and a second nonwoven layer NT2 having a glue line deposited by foil at a second coating point, Coating 2, is passed. Also, two elastic films are passed side by side and spaced apart from each other between the two nonwoven layers NT1 and NT2, so that the films are fixed to each other by laminating them to the two nonwoven layers in the laminating gap.

[0174] Upstream of each gap and covering point, each nonwoven layer passes through a wave-forming gap known as a waver or tamper, formed by two toothed rollers called waver rollers or tamper rollers. The teeth of the rollers interpenetrate without contact in the CD, as shown in Figure 4A, forming the two nonwoven layers into a wave shape, which is then introduced into the lamination gap, resulting in the final laminate at the exit from the gap. The relative positions of the waver rollers allow the shape of the waves to be adjusted, particularly in terms of length and height. The number of waves can be adjusted by the number of teeth on the two waver rollers. The two rollers of Figure 4A used in Figure 15 have the dimensions "Pen" between 3 and 6 mm, preferably between 3 and 4 mm, in particular about 3.5 mm, "Diam" between 20 and 50 mm, preferably between 25 and 45 mm, in particular about 38 mm, "R" between 0.1 and 0.7 mm, preferably between 0.15 and 0.6 mm, in particular about 0.51 mm, "PAS" between 1 and 6 mm, preferably between 2 and 5 mm, in particular about 4.32 mm, "Ep" between 0.5 and 3 mm, preferably between 1.2 and 2.3 mm, in particular about 1.91 mm, and "d1" between 1.5 and 4 mm, preferably between 1.7 and 3 mm, in particular about 2.41 mm.

[0175] In the equipment of Figure 15, after the laminate is obtained, and optionally, two toothed rollers are used to stretch the laminate in the transverse direction to "activate" the laminate, i.e., an activation point is also provided to "stretch" the non-elastic or slightly elastic nonwoven fabric and / or elastic film, thereby increasing its stretchability, thereby releasing the elasticity of the elastic material in the laminate and thereby increasing its elasticity.

[0176] 16, two laminating rollers 501 and 502 define a laminating gap, between which passes a first nonwoven layer NT1 having a glue line deposited by foil at a first coating point, Coating 1, and a second nonwoven layer NT2 having a glue line deposited by foil at a second coating point, Coating 2. Two elastic films are also passed side by side into the gap between the two nonwoven layers NT1 and NT2, so that in the laminating gap the films are fixed to each other by being laminated to the two nonwoven layers.

[0177] Upstream of the gap and one of the two covering points, here covering 2, the corresponding nonwoven layer NT2 is passed into a wave-forming gap known as a waver, formed by two toothed rollers called waver rollers, whose teeth interpenetrate without contact in the CD as shown in Figure 4A, shaping the nonwoven layer into the shape of waves, which are then introduced into the lamination gap, thus obtaining the final laminate at the exit from the gap. Depending on the relative positions of the waver rollers, the number of waves, in particular in terms of length units and height, can be adjusted.

[0178] According to an option of the installation of FIG. 16, it is conceivable that the laminating roller 502, together with an optional waver roller 505, forms a wave-forming gap in addition to or instead of the one already provided upstream, thereby performing wave formation directly on one of the two laminating rollers 502.

[0179] Figure 17 shows an example of a curve showing force as a function of elongation for a laminate with a damping effect. The damping effect is characterized by the presence of a stop, i.e., a sudden break in the slope between gradual elongation up to a given elongation (10 N in Figures 18A-18C) without damaging one or more components of the laminate, and a steeper slope thereafter. The stop indicates to the user the optimum range in which the product should be used.

[0180] Braking is defined by the presence of at least three consecutive slope variations: a start slope, an operating slope, and a stop slope, where the operating slope has a smaller (positive) slope than the start slope and the stop slope, but is not zero.

[0181] In particular, according to the present invention, a curve has an inflection point that separates it into a first lower curve segment, whose concave surface faces downward, and a second upper curve segment, whose concave surface faces upward. The first lower segment has a lower vertex, and the second upper segment has an upper vertex. The portion of the curve between the origin (coordinate F=0 for zero stretch percentage (%)) and the lower vertex is the start segment of the curve, the portion of the curve between the lower vertex and the inflection point is the used segment of the curve, and the portion of the curve between the inflection point and the upper vertex is the stop segment of the curve. The start slope can be defined as the average slope of the start segment, the used slope can be defined as the average slope of the used segments, and the stop slope can be defined as the average slope of the stop segments.

[0182] With prior art laminates, there is no gradual hand recoil in the use zone and the user goes directly into the stop zone without a transition that confuses the use zone.

[0183] The use gradient according to the present invention is preferably positioned before 100% elongation. The beginning of the use area according to the present invention is preferably positioned at a force greater than 2 N. The end of the use area according to the present invention is preferably positioned at a force less than 10 N.

[0184] In particular, the X-axis of the start segment extends from 0% to a value between 5% and 20%, for example 10%, the X-axis of the use segment extends from a value between 5% and 20%, for example 10%, to a value between 60% and 80%, for example 70%, while the X-axis of the stop segment extends, following the use segment, to a value between 80% and 120%, in particular up to 100%, as mentioned in the paragraph above.

[0185] 18A, 18B and 18C show example curves for embodiments of stacks according to the present invention.

[0186] Below, three examples of laminates according to the invention, designated E46, E53 and HG1 respectively, are described. [Example]

[0187] Example 1: HG1 The upper nonwoven fabric is 30 g / m 2 The nonwoven fabric is available from SANDLER under the reference SPUNLACE SAWASOFT 2925. Elastic films based on SIS are available in a range of 50 g / m 2 The bottom nonwoven fabric has an average basis weight of 20 g / m 2 The nonwoven fabric is available from FITESA under the reference SPUNBOND HES CD Rod. The structure of Example 1 is as shown in Figure 1b. The product was obtained with a blade penetration of between 3 and 4 mm using the waver of Figure 4A according to the method shown in Figure 15. [Example]

[0188] Example 2: E46

[0189] The upper nonwoven fabric is 25g / m 2 The nonwoven fabric is available from SANDLER under the reference SPUNLACE SAWASOFT2626. The elastic film formed based on SIS50 has a density of 50 g / m 2 The bottom nonwoven fabric is extruded at an average basis weight of 18 g / m 2The nonwoven fabric is available from Texbond SPa under the reference SPUNBOND ULTRASOFT and has a basis weight of 1. The structure of Example 2 is as shown in Figure 1. It contains 17 waves obtained using the waver of Figure 4B by the method shown diagrammatically in Figure 14, with a blade penetration of approximately 2.8 mm. [Example]

[0190] Example 3: E53 Example 3 is similar to Example 2, except that in Example 3 the through-gap is in the region of 2.7 mm, whereas in Example 2 it is in the region of 2.8 mm.

Claims

1. An elastic laminate extending in a first direction, specifically a cross direction, CD, and in a second direction, specifically a length direction, MD, at least one nonwoven layer, at least one elastic film secured to the lower or upper surface, respectively, of said at least one nonwoven layer by the upper or lower surface, respectively; an elastic laminate comprising at least one adhesive layer, in particular a glue, provided between said at least one nonwoven layer and said at least one elastic film, When the laminate is not in a stretched state, the nonwoven fabric layers comprise, in a cross section in the first direction, in particular in a cross section in the CD direction, curved portions in an inverted U shape, in particular in an Ω shape, separated from each other by intermediate portions; an elastic laminate, characterized in that said intermediate portion is in contact with said at least one adhesive layer and said curved portions are not in contact with said at least one adhesive layer.

2. An elastic laminate extending in a first direction, specifically a cross direction, CD, and in a second direction, specifically a length direction, MD, at least one nonwoven layer, at least one elastic film secured to the lower or upper surface, respectively, of said at least one nonwoven layer by the upper or lower surface, in elastic laminates in which the at least one nonwoven layer is fixed to the at least one elastic film in a fixing zone, in particular by ultrasonic welding, calendering or lamination, in particular hot lamination, When the laminate is not in a stretched state, the nonwoven fabric layers comprise, in a cross section in the first direction, in particular in a cross section in the CD direction, curved portions in an inverted U shape, in particular in an Ω shape, separated from each other by intermediate portions; an elastic laminate, characterized in that said intermediate portion is in contact with said at least one elastic film and said curved portions are free from contact with said at least one elastic film.

3. 3. A laminate according to claim 1, wherein the nonwoven layer or layers forming said at least one nonwoven layer extend in said first direction, in particular in said CD direction, over the entire nonwoven width, and the elastic film or films forming said at least one elastic film extend over the entire elastic width, the ratio equal to said entire elastic width to said entire nonwoven width being between 0.3 and 0.9, preferably between 0.4 and 0.

8.

4. 3. A laminate according to claim 1, wherein the curved portions extend in the first direction, in particular in the CD direction, over the entire curved portion width, and the intermediate portions extend over the entire intermediate portion width, the ratio equal to the entire curved portion width to the entire nonwoven width being between 0.25 and 0.85, preferably between 0.35 and 0.

75.

5. The laminate has an initial thickness (e ０ ), and when the laminate is stretched in the first or second direction to a so-called maximum elongation, which is at least equal to 50%, the relative loss of thickness [(e ０ −e(t)) / e ０ 3. An elastic laminate according to claim 1, wherein the curve giving [value] has a maximum value between 5 and 50%, preferably less than 40%, more preferably less than 35%.

6. The initial thickness (e ０ ) minus the thickness of the laminate at maximum elongation (e ｍａｘ ) of the initial thickness (e ０ ), i.e., the ratio [(e ０ -e ｍａｘ ) / e ０ 6. The elastic laminate of claim 5, wherein the .lambda. % of the cross-sectional area is 55% or less, in particular less than 40%, in particular less than 35%, and / or greater than 5%, in particular greater than 10%, in particular greater than 20%.

7. The initial thickness (e ０ ) minus the thickness of the laminate at 100% elongation (e １００ ) of the initial thickness (e ０ ), i.e., the ratio [(e ０ -e １００ ) / e ０ 6. The elastic laminate of claim 5, wherein the .lambda. % of the cross-sectional area is 55% or less, in particular less than 40%, in particular less than 35%, and / or greater than 5%, in particular greater than 10%, in particular greater than 20%.

8. The laminate progresses from a first unstretched state to 100% elongation, and then relaxes to a second unstretched state (0% elongation), resulting in a thickness (e ｖ ) and the thickness (e ｖ ) minus the thickness of the laminate at 100% elongation (e １００ ) across the thickness, i.e., the ratio [(e ｖ -e １００ ) / e ｖ 3. Elastic laminate according to claim 1, characterized in that ] is equal to or less than 60%, in particular less than 50%, in particular less than 40%, in particular less than 35%.

9. 3. An elastic laminate according to claim 1, characterized in that the fixing of the at least one film to the at least one nonwoven layer is carried out by the interposition of an adhesive, for example a glue, along one or more glue strips or lines extending lengthwise in the second direction, in particular the MD direction, and at a distance from each other in the first direction, in particular the CD direction.

10. The elastic laminate of any of claims 1 to 2, wherein said at least one nonwoven layer comprises continuous filaments.

11. The elastic laminate of claim 1 , wherein the at least one nonwoven layer comprises crimped filaments.

12. The elastic laminate of claim 1 , wherein the at least one nonwoven layer comprises a spunbond nonwoven.

13. When the film is stretched to 100% elongation from its initial state, i.e., before its first stretch, and then relaxed to the unstretched state (0% elongation), the thickness (e ｖ ) is the initial thickness (e ０ ) and the ratio [(e ｖ -e ０ ) / e ０ 3. An elastic laminate according to claim 1, wherein the % % elongation is greater than 2%, in particular greater than 5%, more in particular greater than 10% and preferably less than 70%, in particular less than 50%, more in particular less than 35%.

14. 3. The elastic laminate according to claim 1, wherein in the unstretched state of the laminate and / or the elastic film, the nonwoven layers alternately comprise, in the cross-section in the CD, intermediate sections which are in particular straight or substantially straight, or in particular curved, with their concave surfaces pointing upwards and having a curvature less than that of an inverted U-shape, extending in the CD and fixed to the elastic film, and curved sections in the inverted U-shape, in particular Ω-shaped, each consisting of two strand sections proceeding from two successive intermediate sections and meeting at an apex, which are not fixed to the elastic film, remain spaced apart from the elastic film and define an empty space between them.

15. 3. A laminate according to claim 1, wherein the intermediate portions each extend over a distance measured in the CD that is less than 10% of the distance measured in the CD between two intermediate portions originating from two strand portions of an inverted U-shaped portion, in particular an Ω-shape, and in particular between 10% and 50% of said distance.

16. 3. Elastic laminate according to claim 1, characterized in that the elastic film based on an elastomeric composition does not comprise a skin.

17. 15. Laminate according to claim 14, characterized in that at least one strip or line of adhesive, in particular glue, is located between the elastic film and the respective intermediate portion.

18. 15. The laminate of claim 14, wherein each inverted U is Ω-shaped and is defined by two left and right strands that start from a respective intermediate portion and meet at an apex of the inverted U, and wherein one of the two left and right strands of at least one inverted U-shaped portion, or in particular the two left and right strands of at least one inverted U-shaped portion, has a respective curved shape in an initiation zone proceeding from the intermediate portion where it starts, the concave side of the respective curved shape facing towards the elastic film.

19. 3. A laminate according to claim 1, characterized in that an additional nonwoven layer is provided on the other side of the elastic film.

20. 20. Laminate according to claim 19, characterized in that the additional layer is a nonwoven layer based on staple fibers, in particular a carded nonwoven, in particular a spunlaced or carded thermobonded nonwoven.

21. 20. The laminate of claim 19, wherein the nonwoven layer has a first basis weight and the additional nonwoven layer has a second basis weight different from the first basis weight, in particular greater than the first basis weight.

22. 20. The laminate of claim 19, wherein the nonwoven layer has a first stiffness and the additional nonwoven layer has a second stiffness that is less than the first stiffness, in particular the nonwoven layer has an elongation in the CD direction at 5N of less than 70% and the additional nonwoven layer has an elongation in the CD direction at 5N of greater than 70%.

23. 3. A laminate according to claim 1, wherein the undulations forming the inverted U-shaped portions extend over the entire length of the at least one nonwoven layer in the second direction, in particular in the MD direction.

24. 3. A method for producing a laminate, in particular a laminate according to any one of claims 1 to 2, comprising the steps of: - taking an elastic film; - taking a nonwoven layer, in particular a nonwoven with continuous filaments, in particular spunbond; - shaping said nonwoven layer so as to obtain a nonwoven layer in the form of waves separated by an inverted U-shape, in particular a straight or substantially straight intermediate section, or curved or substantially curved, with their concave surfaces pointing upwards and having a curvature less than that of the inverted U-shape, in particular an Ω-shaped continuous configuration in cross section; - fixing the nonwoven layer in the form of waves to the elastic film, in particular on the side of the nonwoven layer opposite the crests of the waves.

25. Baby diapers or adult incontinence pants comprising at least one laminate according to any of claims 1 to 2.

26. 3. An elastic laminate with hooks, comprising a laminate according to any one of claims 1 to 2 and at least one wrap with hooks fixed to the laminate, in particular on the nonwoven layer, preferably in a zone free of waves or inverted U-shapes.

27. 3. A roll comprising the laminate of any one of claims 1 to 2, wherein the laminate has a length greater than at least 1 meter, is wound along an axis perpendicular to an axis in the MD direction, and comprises two adjacent elastic films.

28. 3. Use of a laminate according to any one of claims 1 to 2 to obtain an elastic laminate, in particular in the form of an elastic lug in the waist of a diaper, having the apparent ability to be stretched without the user having the impression that the laminate will break by stretching, said laminate having an initial thickness (e ０ ), and when stretched in said first or second direction to a so-called maximum elongation, which is at least equal to 50%, the relative loss of thickness [(e ０ −e(t)) / e ０ ] has a maximum value between 5 and 50%, preferably not more than 40%, more preferably less than 35%.

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