Method of preparing closure components suitable for use in diapers

A method of preparing closure components and a method of preparing a stable roll of such components. The methods include (a) providing a fastening portion comprising fastening means; (b) providing a continuous web of a material in a machine direction, said web having a first outer major surface and a second inner major surface and a left and right longitudinal edge at least one of said first and second major surfaces being capable of releasably engaging with the fastening means; (c) joining said fastening portion in the machine direction to the inner and/or outer major surfaces of the web so that the fastening means of said fastening portion are exposed; applying at least two first cuts to the web in order to provide at least two flaps each having a top edge and a baseline, each of said at least two first cuts being discontinuous in the machine direction and in a cross direction, each of said at least two flaps bearing at least part of said fastening portions and being connected to the web at least through its respective baseline so that the baselines of said at least two flaps face opposite longitudinal edges of the web; (e) folding over the flaps into a direction from their top edges to their baseline essentially along said base line onto the web so that the fastening means releasably engage with the first outer major surface or the second inner major surface of the web. A closure component and a stable roll made according to the methods are also disclosed.

FIELD OF THE INVENTION

The present invention relates to a method of preparing closure components suitable for use in disposable absorbent articles and to a stable roll comprising a sequence of pre-formed closure components which are obtainable by said method.

BACKGROUND OF THE INVENTION

Disposable absorbent articles comprise diapers but also other absorbent articles such as incontinence briefs, diaper holders, feminine hygiene garments, training pants, panties, underpants and the like.

Such disposable absorbent articles typically comprise closure components which are used to safely secure the absorbent article to the body of the wearer. The fastening means employed in such closure components include, for example, adhesive means such as pressure-sensitive adhesive means but mechanical fastening means are also used. In the case of mechanical fastening means, the closure component typically comprises at least a first component of such fastening means which is capable of engaging with at least a second matching component of said fastening means arranged at another part of the absorbent article. Mechanical fastening means include, for example, mechanical hooks as a first male component and a fibrous material as a second mating female component.

Disposable absorbent articles often employ materials such as woven or non-woven materials having an exposed surface providing a cloth-like feeling in order to increase the comfort of wearing. It was found that the closure components and, in particular, mechanical closure components tend to engage with such surfaces during the manufacturing of the absorbent articles in an uncontrolled way which may adversely affect subsequent steps of the process of manufacturing.

U.S. Pat. No. 6,428,526 discloses a process for attaching and protecting a mechanical fastener material on a disposable absorbent article. The process includes applying a continuous hook material to a substrate web and cutting by a cutter to form individual fastening portions whereby a substantial part of the substrate web bearing the hook material is discarded. The fastening portions are then folded over and releasably engaged.

U.S. Pat. No. 5,759,317 discloses a method of forming a plurality of closure components which comprises providing a composite web which includes a web of hook material. The composite web is divided along first and second, non-intersecting, continuous serpentine division lines which repeatedly traverse across a complete lateral width of the hook web and extend generally longitudinally along a medial region of the composite thus providing a serpentine strip which needs to be discarded. The method according to US '317 does furthermore not allow for a wide variation of the shape of the closure components obtained.

An overriding consideration in the construction of absorbent articles is the cost of manufacturing which includes—besides running the process of manufacturing at high speed and with high reliability—also the requirement of minimizing waste.

It is therefore an object of the present invention to provide a cost-effective method of manufacturing closure components suitable for use in disposable absorbent articles such as diapers which is characterized by a high reliability and can be run at high speed with a reduced amount of waste. Other objects of the present invention can be taken from the following detailed description.

BRIEF DESCRIPTION OF THE INVENTION

The present invention refers to a method of preparing closure components suitable for use in absorbent articles such as diapers, comprising the steps of providing a fastening portion comprising fastening means; providing a continuous web of a material in a machine direction, said web having a first outer major surface and a second inner major surface and a left and right longitudinal edge, at least one of said first and second major surfaces being capable of releasably engaging with the fastening means; joining said fastening portion in the machine direction to the inner and/or outer major surfaces of the web so that the fastening means of said fastening portion are exposed; applying at least two first cuts to the web in order to provide at least two flaps each having a top edge and a baseline, each of said at least two first cuts being discontinuous in the machine direction and in a cross direction, each of said at least two flaps bearing at least part of said fastening portions and being connected to the web at least through its respective baseline so that the baselines of said at least two flaps face opposite longitudinal edges of the web; folding over the flaps into a direction from their top edges to their baseline essentially along said base line onto the web so that the fastening means releasably engage with the first outer major surface or the second inner major surface of the web, and applying further cuts to the web to produce individual closure components comprising said flaps in a folded position, wherein the first and further cuts are applied so that the waste w which is defined as
1−(sum of surface area of the closure components with the flaps being in an unfolded position/surface area of the continuous web)
is less than 0.2. The sum of the surface area of the flaps5is measured in their unfolded, i.e. not folded-over state, and the area of the continuous web is measured prior to applying any cuts4,4′,4″.

The present invention furthermore refers to a method of preparing a stable roll comprising a sequence of pre-formed closure components suitable for use in absorbent articles such as diapers, in machine direction, said method comprising the steps of providing a fastening portion; providing a continuous web of a material in a machine direction, said web having a first outer major surface and a second inner major surface and a left and right longitudinal edge, at least one of said first and second major surfaces being capable of engaging releasably with the fastening means; joining said fastening portion in the machine direction to the inner and/or outer major surfaces of the web so that the fastening means are exposed; making at least two cuts in the web in order to provide at least two flaps each having a top edge and a baseline, each of said at least two flaps bearing at least part of said fastening portion, and being connected to the web at least through its baseline so that the baselines of at least two of said flaps face opposite longitudinal edges of the web; folding over the flaps into a direction from their top edges to their baseline essentially along said base line onto the web so that the fastening means releasably engage with the surface of the web, and winding up the web into a roll.

The present invention furthermore refers to a stable roll comprising a sequence of pre-formed closure components suitable for use in diapers, said roll comprising a continuous web of a material in machine direction having a first outer major surface and a second inner major surface and a left and right longitudinal edge, said web bearing fastening portions and at least two flaps each having a top edge and a baseline, each of the flaps bearing at least part of said fastening portions and being connected to the web at least through its respective baseline so that the baselines of said at least two flaps face opposite longitudinal edges of the web, said flaps being folded over into a direction from their top edges to their baseline essentially along said base line onto the web so that the fastening means3are in releasable engagement with the corresponding surface1a,1bof the web1.

The invention also relates to a closure component suitable for being attached to absorbent articles, said closure component comprising a base and at least two flaps each of said flaps having a top edge and a baseline and bearing at least part of a fastening portion having fastening means, each of said flaps being connected to the base at least through its respective baseline, said base having a first outer major surface and a second inner major surface at least one of which being capable of releasably engaging with the fastening means of the fastener portions of the flaps.

The invention furthermore refers to the use of said closure component comprising at least two flaps in adult incontinence products.

DETAILED DESCRIPTION OF THE INVENTION

As used above and below, the term “absorbent article” refers to articles which are placed against or in proximity of the body of the wearer to absorb and contain the various exudates discharged from the body. The absorbent article preferably is disposable, i. e. it is intended to be disposed after single use and not intended to be laundered or otherwise restored or reused.

Examples of disposable absorbent articles include diapers, adult incontinence products, training pants, feminine napkins, wound dressings and the like.

A preferred embodiment of the absorbent article referred to in the present invention is a diaper. The term “diaper” as used above and below refers to a garment generally worn by infants or incontinent persons that is drawn up between the legs and fastened about the waist of the wearer.

Diapers10may have any desired shape such as, for example, a rectangular shape, an I shape, a T shape or an essentially hour-glass shape the latter being schematically shown inFIGS. 5a) andb). The diaper10typically has a rear waistband section13, a front waistband section12and an intermediate crotch section15which interconnects the rear and front waistband sections12,13.

The diaper10comprises a top sheet11contacting the wearer's skin, a backsheet17onto which the landing zone14shown inFIG. 5a,5bin dotted lines is attached facing outwards and an absorbent core18(schematically indicated inFIG. 5) sandwiched between said top sheet11and back sheet17.

The diaper10comprises closure components7which are usually anchored at the seam sections16to the lateral edges of the rear waistband section13. The closure component7can be joined to only one of the back sheet17and the top sheet11but it is often preferred that the closure components are joined to both the top sheet11and the back sheet17in order to provide a secure and reliable anchoring. Alternatively, the closure component7can also be joined to the diaper in between the top sheet11and the back sheet17.

The closure component7can be joined to the diaper10by various means comprising, for example, pressure-sensitive adhesives, hot melt adhesives or other adhesives, by ultrasonic bonding, thermal bonding applying heat and pressure, by mechanical bonding, stitching or any combination of these bonding methods. The closure component7comprises a fastening portion2having fastening means3which during the use of the diaper typically engage with the landing zone14on the back sheet side of the front waistband section12in order to secure the waistband sections12,13of the diaper10around the wearer. The fastening portion2forms part of the flap5which is folded onto the inner surface1aof the closure component inFIG. 5aand which is unfolded inFIG. 5b.

The above description of the diaper10is meant to be explanatory only and not limiting. Further details on diapers and their construction can be taken, for example, from EP 0,669,121, EP 0,888,101 and U.S. Pat. No. 6,428,526.

The present invention relates to a novel method of preparing closure components suitable for use in absorbent articles and, in particular, diapers10.

In a first step of the method of the present invention a continuous web1of a material is supplied which continuously extends in the machine direction (MD) and has two longitudinal edges1c,1dextending essentially in such machine direction. The continuous web exhibits a first outer major surface1band a second inner major surface1a.

The term “machine direction” (MD) as used above and below denotes the direction of the running, continuous web1of a material during the manufacture of the closure components. In the embodiment of the continuous web1shown inFIG. 1, the machine direction (MD) corresponds to the direction of the longitudinal edges of the web1. The term “cross-direction” (CD) as used above and below denotes the direction which is essentially normal to the machine direction.

The continuous web1may comprise only one material and exhibit a uniform construction in CD, but it preferably exhibits a sequence of two or more zones having different properties in CD whereby such zones preferably continuously extend in MD.

The term “zone” as used above and below refers to a section of the continuous web1in CD exhibiting an essentially uniform construction and/or uniform properties. The different zones can be formed by different materials which are joined to each other, for example, by adhesive means such as pressure-sensitive adhesive means, ultrasonic bonding, thermal bonding, mechanical bonding, stitching or any combination of these bonding methods. It is, however, also possible that different zones are created by “activating” one or more zones of the web. As used above and below, the term “activating” means subjecting the continuous web1, for example, to a mechanical thermal, electrical and/or chemical treatment in order to impart different functionalities to the treated zones of the web.

The different zones may consist essentially of one material but it is also possible that the zones comprise a sequence of two or more layers of materials and/or exhibit substructures in the direction normal to the major surfaces1a,1bof the continuous web.

One or more zones of the continuous web1preferably comprise a backing or carrier film in order to impart structural integrity and/or stiffness to the web1in CD. The backing or carrier film may be selected from a variety of films or sheetings including single- or multilayered films, coextruded films, laterally laminated films or films comprising foam layers. The layers of such films or sheetings may comprise various materials such, as for example, polypropylene, polyvinylchloride, polyethylene terepthalate, polyethylene, polyolefin copolymers or blends of polyolefins such as, for example, a blend of polypropylene, LPDE (low density polyethylene) and/or LLDPE (linear low density polyethylene), textiles, and non-woven and foamed materials. The thickness of the backing is preferably between 30 and 500 μm and more preferably between 40 and 150 μm. The base weight of the backing is preferably between 20 and 500 g/m2, more preferably between 40 and 300 g/m2and especially preferably between 40-200 g/m2.

One or more zones of the continuous web1preferably comprise one or more elastically extensible materials extending in at least one direction when a force is applied and returning to approximately their original dimension after the force is removed.

Elastically extensible materials which are useful in the present invention include materials which preferably are elastically extensible without requiring an activation step. Such materials include elastic, natural or synthetic rubber, rubber foams, elastomeric scrims, woven or non-woven elastomeric webs, elastomeric composites, zero-strain stretch laminates or prestrained stretch laminates.

The elastically extensible materials may be made from a group of materials comprising essentially isotropic or essentially anisotropic materials, respectively. Useful elastic materials preferably exhibit an elongation at break as measured according to ASTM D 882 in the preferred direction of stretchability of at least 25% or more and, more preferably, of more than 50% and most preferably of more than 100%.

Preferred essentially isotropically elastic materials include elastomeric polyurethane materials, or natural or synthetic rubber materials such as, for example, ethylene-propylene-diene copolymers (EPDM), styrene-butadiene-styrene block copolymers (SBS) or styrene-(ethylene-butylene)-styrene block copolymers (SEBS). Elastomeric materials of the A-B or A-B-A block copolymer type which are useful in the present invention, include, for example, those described in U.S. Pat. No. 3,265,765, U.S. Pat. No. 3,562,356, U.S. Pat. No. 3,700,633, U.S. Pat. No. 4,116,917 and U.S. Pat. No. 4,156,673. Other elastomeric materials which may be used to form the elastic means include elastomeric polyamide materials and elastomeric polyolefin and polyester materials. Blends of these elastomers with each other or with modifying non-elastomers are also contemplated. For example, up to 50 wt. %, but preferably less than 30 wt. % with respect to the mass of the elastomeric material can be added as stiffening aids such as polyvinyistyrenes, polystyrenes, polyesters, epoxies, polyolefins or coumarone-indene resin. These stiffening aids tend to improve the flexibility of the elasomeric materials.

Preferred elastic materials are commercially available from Exxon Mobil Corp. under the trademark Vector and from Kraton Polymers Comp. under the trademark Kraton.

Additionally or alternatively it is also possible to subject one or more zones of the continuous web1to an activation treatment in order to render such zones elastically extensible and/or to increase such elastic extensibility, respectively. Preferred activation treatments include, for example, ring rolling, embossing, thermoforming, high pressure hydraulic forming or casting. Elastomeric laminates comprising at least one non-elastomeric skin layer and at least one core layer where the laminate is treated to exhibit preferential activation regions and non-preferential activation regions so that the preferential activation regions can be stretched to an elastic state, is disclosed in EP 0,521,388. This elastomeric laminate is useful in the present invention whereby the fastener portions2are preferably adhered to the non-preferential regions.

The continuous web1may comprise further materials such as, for example, stiffening materials, adhesive coatings and release materials such as release coatings or release tapes, coloured films, printings or registered marks. The continuous web1may also impart further functionalities such as breathability or differential stiffnesses to the continuous web1. In case adhesive type fastening means are used printed release coatings may applied to part of the surface of the continuous web1.

Stiffening materials include, for example, thermally or sonically structured surfaces or additional layers or coatings applied to the continuous web1.

The continuous web1and, optionally, further components attached to it, preferably has a Gurley stiffness value both in CD and MD as evaluated according to TAPPI Standard Test T 543 om-94, of less than about 1,000 milligrams (mg) in an area of said continuous web including the fastening portion2, i.e. after the fastening portion2has been assembled to the continuous web1as described below. The Gurley stiffness both in CD and MD preferably is less than 500 mg and especially preferably less than 200 mg.

The process of the present invention further includes providing fastening portions2which may be continuous or form individual, single patches.

The fastening portion2comprises a fastening means3which may be provided by adhesive fastening means, by mechanical fastening means, and/or by other male/female fastening means.

The adhesive of adhesive type fastening means3may be selected from a group of adhesives comprising hot-melt adhesives, UV- or thermally curable adhesives or pressure-sensitive adhesives. Pressure-sensitive adhesives are preferably selected from (meth)acrylate and/or natural or synthetic rubber based pressure-sensitive adhesives. Rubber-resin adhesives preferably comprise in addition to the rubber materials one or more tackifying resin in order to render the rubber materials tacky. Preferred examples of rubber-based pressure-sensitive adhesives are the polystyrene-polyisoprene block copolymers tackified with synthetic polyterpene resins. Suitable acrylate-based pressure-sensitive adhesives are disclosed, for example, in U.S. Re 24,906 or U.S. Pat. No. 4,710,536.

Fastening portions2comprising mechanical fastening means3preferably form part of a mechanical closure system comprising at least two interlocking, releasably engageable fastening means, one of them being a hook (or male) fastening means and the other being a loop (or female) fastening means. One of the fastening means of the mechanical closure system forms the fastening means3of the closure component7of the present invention, and the one or more further fastening means of the closure system are attached to other parts of the absorbent article like, for example, to the landing zone14of a diaper10, so that such article can be secured, for example, to the body of the wearer.

A preferred mechanical fastening portion2comprises a base and a plurality of engageable fastening elements forming fastening means3. In case of hook-type fastening means3, the fastening elements usually comprise a stem supported at the base of the fastening portion2and an enlarged section which is positioned at the end of the stem opposite of the base. The enlarged section may have any shape such as hooks, T's, essentially flat discs, mushroom heads, or any other shape allowing for engagement with the corresponding loop fastening elements.

Mechanical fastening portions2comprising hook-type fastening means can be manufactured from a wide range of materials including nylon, polyester, polyolefins or any combination of these. Hook-type fastening portions which are useful in the present invention are disclosed, for example, in U.S. Pat. No. 4,894,060, U.S. Pat. No. 5,077,870 and U.S. Pat. No. 5,679,302. Preferred hook-type fastener portions2are commercially available from 3M Comp., St. Paul, Minn., U.S.A.

In case of loop-type fastening means3, the fastening elements are usually formed by woven or non-woven fabrics or any other suitable material which interlocks with the corresponding hook fastening elements. Loop-type mechanical fastener portions include, for example, fiber loops projecting from a knitted, woven or non-woven backing or extrusion-bonded, adhesive-bonded and/or sonically-bonded fiber loops. Suitable loop-type fastening portions2comprising knitted or extrusion-bonded fastening means are commercially available, for example, from 3M Comp., St. Paul, Minn., U.S.A.

Fastening portions2comprising mechanical fastening means preferably comprise a base or backing bearing fastening elements on one of its surfaces and an adhesive layer on the opposite surface. The fastening means2is then attached to the continuous web1via such adhesive layer. The base or backing may be selected from a variety of polymeric films or sheetings, sheetings of paper and other woven or non-woven fibrous materials or metal film. The adhesive layer preferably comprises hot-melt adhesives or pressure-sensitive adhesives which are preferably selected from (meth)acrylate and/or natural or synthetic rubber based pressure-sensitive adhesives. The fastening portion2can also be thermally, mechanically or ultrasonically bonded to the continuous web1.

The fastening means3of the fastening portion2and the inner and/or outer surface1a,1bof the continuous web of a material1are selected so that they releasably engage upon folding over flap5obtained by applying cuts4around at least part of the fastening portion2as is described in detail below.

The term “releasable engagement” means that the flap5when folded over onto the corresponding target surface1a,1bof the base7aof the closure component interacts sufficiently strong with such surface so that the flap5is deactivated, i.e. essentially rendered immobile during processing and does not pop open during processing. The interaction must be, however, not too strong so that the flap can be releasably activated, i.e. unfolded, when the absorbent article is used and applied, for example, to the wearer. It may be desirable that the flaps5upon folding over are subjected to an additional pressing step in order to provide a secure releasable engagement. This can be obtained, for example, by passing the continuous web1bearing the flaps in the folded-over state between two rotatable nip rollers. Using an additional pressing down step is often desirable in case of mechanical fastener portions2.

The term “releasable engagement” quantitatively means that the fastening means3preferably exhibits a 180° T-peel adhesion of not more than 2 N/inch from the inner and/or outer surface1a,1bof the continuous web1which the fastening means3contacts upon folding-over of said flap5. The 180° T-peel adhesion which is measured according to ASTM-5170-91 is preferably not more than 2 N/inch, more preferably below 1.5 N/inch and especially preferably below 1 N/inch. The 180° T-peel adhesion preferably is higher than 0.1 N/inch and more preferably higher than 0.2 N/inch to secure adequate bonding of the flap5to the base7aof closure component7during processing. Because of this releasable engagement the flap5bearing the fastening portion2is releasably secured to the continuous web1during the process of manufacturing of the closure components and does not pop open. This allows to run such process of manufacturing with high reliability and at high speeds and therefore to reduce manufacturing costs without damaging the fastening portions2and/or the manufacturing equipment.

If the flap5would not be brought into releasable engagement with the corresponding target surface1a,1bof the base7aof closure component7the flap5could possibly engage to the opposite surface1a,1bof such target surface. This could significantly reduce the attainable speed of the manufacturing process or could even stop such process.

If the fastening portion2comprises a hook-type fastening means, the portion of the inner or outer surface of the web which comes into contact with the hook-type fastening means upon folding-over of the flap5, preferably comprises a woven or non-woven fibrous material and/or loop fastening elements. Likewise, in case the fastening portion2comprises a loop-type fastening means3, the corresponding portion of the inner or outer surface of the continuous web preferably comprises hook-type fastening elements. If the fastening portion2comprises an adhesive-type fastening means3, at least the portion of the inner or outer surface of the continuous web1which comes into contact with the adhesive fastening means upon folding-over of flap5preferably exhibits a low surface energy. Such surface portion of the continuous web preferably is release-treated and, in particular, siliconized. It is also possible that the full surface of the continuous web is release-treated.

The fastening portion2may be provided continuously by unwinding it, for example, from a storage roll22and by subsequently continuously applying it to the continuous web of a material1. It is also possible that the fastening portion2is provided continuously but cut into single, individual patches which are applied individually to the continuous web. It is furthermore also possible that the fastening portion2is provided discontinuously in the form of separate, individual patches which are temporarily attached, for example, to an auxiliary web. The separate, individual patches of the fastening portion are then secured to the continuous web1, and the auxiliary web is wound up.

It is often preferred that the fastening portion is supplied continuously but attached discontinuously, i. e. that the continuous fastening portion is cut into separate, single segments prior to their application to the web. This technique avoids creating of additional waste because an auxiliary carrier web is not required, and it facilitates cutting of the flaps5because the simultaneous cutting of both the continuous web1and the fastening portion2is avoided.

The fastening portions2are applied to the continuous web1so that the fastening means3representing the plurality of fastening elements are exposed.

The fastening portions2can be applied to one or to both of the outer major or inner major surface1a,1b, respectively, of the continuous web of a material1. The fastening portions2can also be arranged in various configurations on the continuous web including symmetrical or non-symmetrical, staggered or parallel or other configurations. The specific configuration chosen depends on various factors such as the size and symmetry of the closure components7to be manufactured, the tolerable amount of waste and the further processability of the closure components.

In the specific embodiment ofFIG. 1, for example, the fastening portions are arranged on one surface of the continuous web in a staggered configuration along the centerline of the continuous web1in MD. The cuts4introduced into the continuous web1(seeFIG. 2) and the subsequent folding-over of the flaps5(seeFIG. 3) results in two continuous sub-webs of closure components7(one of which is shown inFIG. 4b). The closure components7of both sub-webs are symmetrical and of an identical shape. Since the two sub-webs are arranged with respect to each other at a rotation angle of 180°, the closure components7of the two sub-webs can be directly applied without any further rotation to different sides of the rear waistband portion13of a diaper as shown inFIG. 5, for example. The waste generated during this process of manufacturing which is represented by the bridges6,6′, is minimal.

Thus, in view of the properties of the closure components7to be generated in the specific process schematically shown inFIG. 1-4a,4b, it is advantageous to apply the fastening portions2in a staggered configuration onto one surface1a,1bof the continuous web1only.

Contrary to this it is advantageous, for example, in the specific embodiment shown inFIG. 10to apply fastening portions2subsequent to each other in MD, in an alternating fashion to the inner and outer major surfaces1a,1b, respectively, of the continuous web1. If the fastening portions2were applied to one surface of the continuous web1only, the resulting non-symmetrical closure components7could only be applied to one side of the rear waistband section. By applying subsequent fastening portions2to different surfaces of the continuous web1in an alternating fashion, a continuous web1of non-symmetrical closure components7is obtained which can alternately be applied to the right and left side, respectively, of the rear waistband section13. It should also be noted that the process of manufacturing shown inFIG. 10does not generate any waste.

It is clear from these specific embodiments which were described to exemplify the invention without limiting it, that the specific configuration of the fastening portions2has to be selected and optimized in each case with respect to the shape and dimensions of the closure components7and their desired attachability to one or both sides of the rear waistband section13to be manufactured and the requirements of the process such as the tolerable amount of waste. Processes according to the present invention are preferred where the fastener portions2and their respective positioning on the continuous web1, and the cuts4,4′,4″ are selected to provide a multitude of pairs of a first and a second closure component7so that one of such closure components can be attached to the right and the other to the left side of the rear waistband portion of a diaper, respectively.

It is generally desirable that the surface coverage of the fastening portions2which is defined as the ratio of the sum of the areas of the fastening portions over the area of the continuous web is between 0.001 and 0.25 and more preferably between 0.025 and 0.175.

The fastening portion2can be adhered to the continuous web1, for example, by adhesive means such as pressure-sensitive adhesive means, hot-melt adhesives or other adhesives, by ultrasonic bonding, thermal bonding and/or mechanical bonding. The adhesive means and/or the bonding conditions are preferably selected so that the fastening portion2is strongly bonded to the continuous web1and cannot be removed from such web without irreversibly deforming and/or damaging the continuous web1and/or the fastener portion.

In the next step, the continuous web1and, optionally, further components attached to it are cut to provide foldable flaps5. The term “cut”4as used above and below includes full slits or cuts fully separating two adjacent portions of the continuous web1and, optionally, further components attached to it, and also intermittently arranged slits or cuts, perforations and the like. Full cuts4are preferred. The term “flap” is used above and below to denote a section of the continuous web1which is partly separated from the surrounding continuous web1by one or more cuts4and which is still partly connected to the surrounding continuous web1and/or a continuous sub-web obtained from it, respectively, at least through its baseline5b. The separated part of the flap5can be folded over along the baseline5btowards the surrounding continuous web1whereby in case of perforations or intermittently arranged cuts, the remaining connections between the flap5and the adjacent portions of the continuous web1need to be broken. The cuts4providing the flaps5preferably are discontinuous in MD and CD, i.e. they do not destroy the integrality of the continuous web1in CD or MD, respectively. Discontinuous cuts4are shown, for example, inFIGS. 2 and 3where the cuts discontinuously extend around the fastening portion2but do not extend continuously in CD or MD, respectively. The integrality of the continuous web1is maintained, for example, inFIG. 3via the bridges6. It was found that folding over of the flaps5is facilitated in particular, under high speed processing conditions when the continuous web1is maintained in a connected, i.e. integral state in CD and MD prior to the folding over step.

The baseline5bwhich thus essentially forms a rotation axis for the separated part of the flap5, preferably is a straight line. The extension of the baseline5bcan vary and can be reduced so that the baseline5bhas, for example, a length of 1 mm only. The extension of the baseline5bshould be selected, however, so that the separated part of the flap5is reliably secured to the surrounding part of the web1and so that such separated part of the flap5can be rotated around such baseline without being separated from the surrounding part of the web1.

The separated part of the flap5and the surrounding continuous web1can be separated by one or more cuts4which are arranged so that the separable part comprises at least part of the fastening portion2. The cut or cuts4can form essentially straight lines but they can be of any shape and exhibit, for example, a convexly or concavely curved shape or exhibit, for example, a wavy substructure.

The cut line of the separated part of the flap5which is essentially opposite to the baseline5bis denoted above and below as top edge5aof the flap5. The top edge5acan have any shape and may be represented, for example, by a straight or a convexly and/or concavely curved line, by two or more straight and/or curved lines intersecting with each other or it may include, for example, a wavy or sawtooth-like substructure.

The baseline5bpreferably is essentially parallel with one of the longitudinal edges1c,1dof the continuous web1so that the flap5is rotated upon folding essentially into CD. It is also possible, however, that the baseline5bforms an angle with respect to the longitudinal edges1c,1dof the continuous web1so that the flap5is rotated upon folding along the baseline5bessentially under such angle with respect to CD.

Irrespective of whether the baseline5bis essentially parallel to a longitudinal edge1c,1dof the continuous web1or forms an angle with such longitudinal edge1c,1d, such baseline5bis referred to as facing the longitudinal edge1c,1dwhich is closest to it.

The method according to the present invention provides at least two flaps5along the extension of the continuous web in MD which are facing opposite longitudinal edges1c,1dof the continuous web1. It was found by the present inventor that the waste generated during the manufacture of closure components can be minimized if the longitudinal web1comprises in MD at least one flap5facing the right longitudinal edge1dand at least one flap facing the left longitudinal edge1c, respectively.

The flap density is measured along the extension of the continuous web1in MD as the number of flaps per length unit. The overall flap density preferably is between 3/m and 300/m and more preferably between 5/m and 150/m.

The flap density of the flaps5which are facing the right longitudinal edge and the flap density of the flaps which are facing the left longitudinal edge, preferably deviate from each other by less than 50%, more preferably by not more than 40% and especially preferably by not more than 30% with respect to the lower value of the right and left flap density, respectively.

The length of the flap5in CD and/or normal to the baseline5b, respectively, is defined by the distance between the baseline5band the top edge5aof the flap5. If the baseline5band the top edge5aare not parallel to each other and/or if the top edge5ais not linear, the maximum value of such distance is reported as the length of the flap5in CD and/or normal to the baseline5b. Such length preferably is at least 10 mm, more preferably at least 15 mm and especially preferably at least 20 mm. The length of the flap preferably is between 25 mm and 250 mm, more preferably between 30 and 150 mm and especially preferably between 35 and 100 mm.

The shape and extension of the one or more cuts4and the shape and extension of the baseline5bof the flaps5essentially determine the size and the shape of the flaps5.

The flaps5can be symmetrical or non-symmetrical, respectively, for example, with respect to a direction normal to the baseline5b. The width of the flap is defined as the extension of the flap in MD or in a direction parallel to the baseline5bif the baseline is not parallel to the longitudinal edge of the continuous web whereby such extension is measured at about half of the height of the flap. The width of the flap5preferably varies between 8 and 200 mm, more preferably between 10 and 180 mm and especially preferably between 12 and 150 mm.

The size and shape of the flap5is selected so that it comprises at least part of the fastening portion2. If such fastening portion2comprises a plurality of individual, single patches each flap may comprise one or more and, preferably, one, of such individual patches or fastening portion2.

If the fastening portion2forms a continuous web applied to the continuous web1of a material in MD, the fastening portions2on the different flaps5are cut along with the continuous web1and, optionally, further materials attached to the continuous web1, during the cutting step.

The cut or cuts4, respectively, can be applied to the continuous web1so that the fastening portion2is located essentially in the center of the flap, i. e. the distance between the top edge5aof the flap5and the center of the fastening portion2essentially equals the distance between the baseline5bof the flap and the center of the fastening portion2. It is also possible that the cut or cuts4are applied to the continuous web so that the fastening portion does not have a centered position with respect to the flap5. In this case it is preferred that the distance between the top edge5aof the flap and the center of the fastening portion2is between 0.05 and 0.8 and more preferably between 0.1 and 0.7 of the distance between the baseline5band the center of the fastener portion.

Although it is possible that the fastening portion essentially extends to the top edge5aof the flap5it is preferred that there is a distance between the top edge5aof the flap and the edge of the fastening portion2facing such top edge5a. This construction provides a soft-edge finger-lift between the top edge5aand the edge of the fastening portion facing the top edge5awhich facilitates gripping and unfolding of the flap5. The fingerlift preferably has a length, i.e. an extension in CD and/or along a direction normal to the baseline5bof the flap, of at least 1 mm, more preferably of at least 2 mm and especially preferably of at least 3 mm.

The flaps5are then folded over in the next step in a direction essentially normal to the baseline5bso that the fastening elements of the fastening portion2are brought into contact and releasably engage with the continuous web1between the baseline5band the longitudinal edge1c,1dsuch baseline is facing.

The part of the continuous web1upon which the fastening portion2is folded and with which it releasably engages, forms the base7aof the closure component7. The individual closure components7are obtained from the continuous web by applying additional cuts4′,4″. The cuts4′,4″ can be full slits or cuts but intermittently arranged slits or cuts, perforations and the like can also be used. The cuts4′,4″ can be used to break down the continuous web1into continuous sub-webs, and/or they can also be used to provide single separated closure components7. The cuts4′ applied inFIG. 4a, for example, provide two separate sub-webs one of which is shown inFIG. 4b. Single separated closure components7are then obtained from the sub-web ofFIG. 4bby applying additional cuts4″.

The cuts4′,4″ can be continuous or discontinuous The cuts4′ applied inFIG. 4a, for example, are discontinuous in MD and extend between adjacent flaps5facing one edge of the continuous web whereas the cuts4″ applied inFIG. 4bare continuous in CD of the sub-web and provide separated single closure components7.

The cuts4′,4″ applied are selected so that the closure component7comprises at least one flap5. The closure component7may comprise, for example, two flaps5,5′ which may be of identical or different shape. The two baselines5b,5b′ of such flaps5,5′ may be arranged in one line or they may be offset with respect to each other. In contrast to the prior art methods for providing closure components such as those disclosed in U.S. Pat. No. 5,759,317 the method of the present invention is very versatile and allows, for example, for the production of flaps5of various shapes and of closure components having more than one flap5.

Using two or more flaps5per closure component7may be especially advantageous in adult incontinence articles where the base7aof the closure component may be large.

In baby diapers10it is generally preferred for cost reasons that the closure component comprises one flap5only.

The cuts4,4′,4″ applied in the method of the present invention are selected so that the waste w generated during the manufacture of the closure components7which is defined as
1−(sum of surface area of the closure components with the flaps being in an unfolded position/surface area of the continuous web)
is less than 0.2. The waste w preferably is less than 10%, more preferably less than 7.5%, especially preferably less than 5% and most preferably less than 2%.

This minimization of waste is obtained by providing at least two flaps5along the extension of the continuous web1in MD which are facing opposite longitudinal edges1c,1dof the continuous web1and by appropriately applying cuts4,4′,4″.

The specific embodiments of the present invention illustrated inFIG. 1-12below give ample guidance how minimization of waste can be achieved by appropriately selecting cuts4,4′ and4″. InFIG. 4a, the waste generated is represented by bridges6,6′. While a small amount of waste is also generated in the embodiments ofFIGS. 8 and 11, no waste is generated in the embodiment ofFIG. 10at all.

The height of the closure component7comprising the flap5in its folded state is typically given by the distance between the baseline5bof the flap5and the baseline of base7awhich usually corresponds to the longitudinal edge1c,1dof the continuous web1such baseline5bfaces. The baseline of the base7aof the closure component7represents the boundary line of the base7ain CD. The height of the basis7aof the closure component7is selected so that at least part of the fastening elements of the fastening portion2releasably engages with the surface of the continuous web1upon folding over. The top edge5aof the flap5may exceed beyond the corresponding longitudinal edge1c,1dupon folding over to an extent that the fastening elements of the fastening portion2still releasably engage with the continuous web1. In this embodiment the height of the flap5is larger than the height of the base7aof the closure component7. In another embodiment which is also preferred, the height of the flap5is smaller than the height of the base7aof the closure component7. The ratio of the height of the flap5and the height of the closure component7preferably varies between 0.05 and 2 and more preferably between 0.1 and 1.5.

Depending on the height of the base7aof the closure component7, one or more closure components7can be obtained in the CD of the continuous web1. If the closure component7essentially extends over the width of the continuous web1in CD so that only one closure component7is obtained in CD (see, for example,FIG. 10), the continuous web may be wound into a stable roll for storage. If the continuous web1comprises along its width in CD more than one closure component7as exemplified inFIG. 4a,borFIGS. 8 and 9, two or more continuous sub-webs may be obtained upon cutting (see, for example,FIG. 4b) which each may be wound up into stable rolls for storing. Alternatively, prior to winding the sub-webs for storage, the bridges6,6′ which may still be present between the sub-webs to form an integral web1, can be weakened by introducing, for example, perforations into such bridges. The bridges connecting, for example, the two sub-webs ofFIG. 4aare denoted therein with the reference number6. After introducing such perforations the continuous web1can be rolled up and stored. The sub-webs can then be obtained by merely unwinding the roll and separating the continuous web1by tearing it in CD thereby breaking said perforations. This eliminates one cutting operation on high speed manufacturing lines such as manufacturing lines for disposable diapers. This configuration of the roll of the continuous web1also eliminates the need to inventory ‘right hand’ and left hand’ rolls of the sub-webs as both are contained in one stable roll.

The individual closure components7can then be obtained by unwinding such rolls and cutting. A specific example of a continuous web1containing one closure component7in CD, is shown inFIG. 10. Alternatively, when the cuts4′,4″ are introduced as weakened lines such as perforations prior to winding up the roll for storage, the closure components7can be obtained by unwinding the rolls and tearing the web to break such perforations.

If the continuous web1comprises two or more closure components in CD, the continuous web1is preferably cut into continuous sub-webs first each of them comprising one closure component7in CD. This is exemplified inFIGS. 4aand4bfor a continuous web1comprising two closure components7in CD. The continuous sub-webs obtained upon cutting can each be wound into a stable roll for storage. One of the two sub-webs obtained from the continuous web1ofFIG. 4ais shown inFIG. 4b. Each of the sub-webs can be wound up in single planetary or levelwinding format or may be festooned since the fastening means3of the fastening portions2are releasably engaged to the surface of the base7aof the closure component, i.e. since the fastening means are temporarily deactivated. The individual closure components7can be obtained by unwinding the roll and cutting.

The width and shape of the base7aof the closure component7can be varied broadly. The width of the base7a, i. e. its extension in MD, can be less than the width of the closure component although this is usually not preferred. The width of the basis7aof the closure component7can be distinctly greater than the width of the flap5to provide so-called “big ear”-type closure components7. Closure components of this type provide both a closure system and an ear region to an absorbent article as is schematically illustrated for a diaper having an hour-glass shape, inFIGS. 5aand5b. The ear-region partly overlaps with the front waistband portion12upon securing the diaper to the body of a wearer to provide a reliable and comfortable fit.

When using big-ear type closure components7the chassis of the diaper can have, for example, a rectangular shape which considerably facilitates manufacturing of the diaper.

The ratio of the width of the base7aof the closure component7and the width of the flap5preferably is between 0.5 and 20, more preferably between 0.8 and 18 and especially preferably between 1 and 15.

The shape of the base7aof the closure component7can vary broadly and includes, for example, essentially rectangular or trapezoidal shapes shown inFIGS. 4b,9and10.

In the first step of the method according to the present invention the fastening portion2and the continuous web1are provided, and the fastening portion2is fastened to the continuous web1. Any method capable of bonding different materials together is considered suitable in the method of the present invention. The fastening portion2can be joined to the web1, for example, by adhesive bonding, ultrasonic bonding, thermal bonding, mechanical bonding and/or stitching whereby bonding of the fastening portion2can be effected via part or all of the surface of the fastening portion which is opposite to the fastening means3.

Cutting the web1in order to provide flaps5may be performed by using rotary cutters, air knives, thermal knives, pinch cutters, ultrasonic cutters or lasers. Folding-over of the flaps5around its baseline5bonto the base7aof the closure component7may be effected, for example, by using a sprocket wheel in conjunction with a folding bar or plows. If desired and/or necessary, the flaps5may subsequent to the folding step be pressed into contact with the surface of the base7aof the closure component7in order to reliably engage the fastening elements of the fastening portion2with the surface of the base7aof the closure component7. This may be obtained, for example, by passing the web1comprising flaps5being folded over through a pair of rotatable nip rolls.

The resulting construction can then be wound up for storing, for example. The resulting construction can also be subjected to further cutting in order to provide sub-webs8and/or single closure components7.

A specific example of the process of the present invention is described in some detail below in connection withFIG. 6.

In the process of the present invention, the fastening portion2of the flaps5is releasably engaged with the base7aof the closure component7so that the flaps5do not pop open or flutter even at high manufacturing speeds. This could result in damaging the fastening portion2, other parts of the absorbent article to be manufactured and/or the manufacturing equipment.

In addition to this, the process of the present invention provides a low or very low amount of waste. This is obtained by providing at least two flaps5along the extension of the continuous web1in MD which are facing opposite longitudinal edges1c,1dof the continuous web1.

The invention will now be explained by referring to the specific embodiments ofFIG. 1-10. These specific embodiments are to illustrate the invention without limiting it.

FIG. 1shows a section of a continuous web1having two parallel longitudinal edges1c(left edge in MD) and1d(right edge in MD). Individual fastening portions2comprising fastening means3are applied discontinuously in a staggered configuration along the (hypothetical) centerline of the continuous web.

InFIG. 2, cuts4have been applied around each fastening portion2to provide essentially rectangular flaps5. The baseline5bwhich is defined by the two end-points of the cut line4, is essentially parallel to the respective longitudinal edge1c,1dsuch baseline5bfaces. The baselines5bof two subsequent flaps5face opposite longitudinal edges1c,1dso that a sequence of flaps5is obtained which are foldable to opposite longitudinal edges in an alternating fashion.

The top edge5aof the flap5which is essentially parallel to the baseline5bexceeds the upper edge of the fastening portion2to provide a fingerlift.

The configuration ofFIG. 3has been obtained by folding over the flaps5ofFIG. 2to the corresponding longitudinal edges1c,1d. The fastening portions2which are shown in dotted lines are in contact with the surface1aof the continuous web1. The integrity of the continuous web1is maintained through the bridges6in the middle of the continuous web1.

InFIG. 4a, the continuous web1ofFIG. 3is separated into two continuous sub-webs by means of cuts4′. The cuts4′ are formed by two intersecting straight lines whereby the point of intersection defines the point of cutting for providing individual closure components7as can be seen inFIG. 4b. One of the two sub-webs which can be wound into stable rolls if desired, is shown inFIG. 4b. It is also possible, however, that the closure components7are cut and processed directly without an intermediate winding and storage step.

The waste generated during the process of manufacturing shown inFIG. 1-4a,4bwhich is represented by bridges6and6′, is relatively small and tolerable.

FIG. 5schematically shows the closure components7obtained inFIG. 4bbeing attached to a diaper10. The diaper10essentially has an hour-glass shape and comprises a rear waistband section13, a crotch section15and a front waistband section12. The absorbent core18of the diaper10which is schematically indicated for purposes of demonstration only, is sandwiched between the top sheet11forming the inside of the diaper and the outer backsheet17. The closure components7are secured to both lateral ends of the rear waistband portion13via seam sections16. Bonding of the closure components7can be effected by various methods including, for example, adhesion bonding, ultrasonic bonding, thermal bonding or mechanical bonding. InFIG. 5a, the flap5is folded over to the base7aof the closure component7. The closure component7is obtained in this configuration in the process of the present invention as is shown inFIG. 4a,4b. InFIG. 5b, the flap5has been folded back so that the fastening portion2is exposed. In this configuration, the fastening elements of the fastening portion can be engaged with the corresponding fastening elements of the landing zone14applied to the backsheet17of the diaper10.

FIG. 6schematically shows a method of manufacturing the closure components7ofFIG. 4band the corresponding equipment. The continuous web1of a material is unwound from supply roll21and fed into a lamination station24a,24bwhere individual patches of fastening portion2are laminated to the continuous web1. The individual fastening portions are obtained by unwinding a continuous fastening portion2from supply roll22which is cut by cutting means23. The individual, single patches of fastening portion2are bonded to the continuous web1by means of a pressure-sensitive adhesive which is attached to the base of the fastening portions2. The individual patches of fastening portion2are held in place during lamination by vacuum roller24b. The resulting continuous web1comprising individual fastening portions2is shown inFIG. 1.

The cuts4are applied around the fastening portion2through the continuous web1by the rotary cutting means25a,25bcomprising a rotary cutting wheel25b. The flaps5thus prepared which are shown inFIG. 2are folded over by means of the sprocket wheel26ain conjunction with sprocket wheel26aand folding bar26b. The resulting continuous web1comprising flaps5which are folded over, is shown inFIG. 3. This construction can be wound onto storage roll28and stored.

Alternatively, the continuous web1comprising flaps5being folded over as shown inFIG. 3can be passed through rotary cutting means29a,29bto provide additional cuts4′ as shown inFIG. 4c. Because of these additional cuts4′ the construction ofFIG. 4ais separated into two continuous sub-webs8from which individual closure components7can be cut. One of such sub-webs8is shown inFIG. 4b. The two sub-webs8ofFIG. 4bcan be wound onto storage rolls30a,30band stored.

The continuous web1ofFIG. 7bears a plurality of individual patches of fastening portion2being arranged in pairs directly opposite to each other along the centerline of the continuous web1. The individual patches of fastening portion2comprise fastening means3.

FIG. 8shows a plurality of flaps5which are obtained by applying cuts4around the individual patches of fastening portion2. The flaps comprise a top edge5aand a baseline5bwhich is defined by the end points of the lateral cuts providing the sides of the flaps5.

The flaps are folded around their baseline5btowards the respective longitudinal edge1c,1dwhich is faced by such flaps5as is shown inFIG. 9. Individual closure components7can be cut from the two continuous sub-webs8ofFIG. 9.

The individual closure components7which can be obtained from the sub-web8ofFIG. 4bandFIG. 9, respectively, are symmetric. These symmetric individual closure components7can be applied, for example, to both lateral ends of the rear waistband section13as is schematically shown inFIG. 5.

Contrary to this, subsequent closure components7which can be cut from the continuous web1ofFIG. 10can be applied to different ends of the rear waistband section13only if the individual patches of fastening portion2are applied to different surfaces1a,1bof the continuous web. This results from the unsymmetrical shape of the closure components7ofFIG. 10. The corresponding structure is shown inFIG. 10where cuts4have been provided around the fastening portions2to provide flaps5, the cuts4are indicated by solid bold lines. The flaps5thus obtained have not yet been folded over inFIG. 10, the further cuts4′ which are required to provide individual closure components7are shown in bold dot-dash lines. The waste generated when manufacturing the closure component7according toFIG. 10, is zero.

If the fastening portions2were applied in the construction ofFIG. 10only to one surface of the continuous web, the resulting closure components could only be used on one side of the rear waistband section13of diaper10, for example. In this case, two different production runs would be required applying the fastening portion2in a first run, for example, to surface1aand in the second run to the other surface1bof the continuous web, respectively.

FIG. 11schematically shows the continuous web1of a material bearing discrete fastening portions2,2′ having a different size. The smaller fastening portions2are arranged directly opposite to each other along the centreline of the continuous web in MD, and they separate two adjacent larger fastening portions2′ from each other. The larger fastening portions2′ are arranged along the centreline of the continuos web in MD in a staggered configuration with respect to each other.

The fastening portions2,2′ are arranged on flaps5,5′ which likewise are of a different size. The flaps5,5′ which are defined by cuts4(shown in bold lines) each have a top edge5a,5a′ and a baseline5b,5b′.

The flaps shown inFIG. 11have not yet been folded over. Subsequent to such folding over step, further cuts4′ are applied (shown in bold dash-dotted lines) to provide a plurality of individual closure components one of which being shown inFIG. 12.

The closure component7ofFIG. 12which comprises two flaps5,5′ and two fastening portions2,2′, is especially suited for use in adult absorbent articles such as adult incontinence products.