The present application relates to fastening tabs for disposable, absorbent articles, fastening tapes and rolls of fastening tape including such fastening tabs as well as absorbent articles comprising fastening tabs and methods of manufacturing and using such absorbent articles.
Disposable, absorbent articles, such as diapers and incontinence briefs, are widely used not only in the sector of child care, but also for adults suffering from incontinence. The absorbent articles are typically reclosable by fastening tabs that are generally easy to handle and provide reliable fixation.
Generally such fastening tabs either comprise an adhesive-based closure mechanism or a mechanical-based closure mechanism or a combination of both. Fastening tabs relying on a mechanical closure mechanism typically comprise hook-like fastening elements whereby the tab is normally attached to the rear waist portion of the diaper or incontinence brief or, if applicable, to an ear thereof. A large number of documents described such fastening tabs including among others for example EP 2 103 293, WO 2000/013641, and EP 2 055 283. For closing diapers or incontinence briefs provided with such fastening tabs, the fastening tab is typically fastened to a landing zone provided on the front waist portion of the diaper or incontinence brief, respectively. For this purpose, the landing zone typically comprises a surface with a loop material being adapted to engage the hooks of the fastening tab. The provision of such a landing zone may be omitted, when the back sheet of the diaper or the incontinence brief is made of a material that is suitable to engage with hooks of the fastening tab or when the fastening tab includes a so-called loop-transfer element, where upon during initial use of the tab, a piece of loop-comprising material engaged to the hooks on the fastening tab is transferred from the tab onto the front portion of diaper or incontinence brief, as the case may be. Documents describing loop-transfer tabs or tapes include among others U.S. Pat. No. 5,383,872, EP 1 449 505 and EP 1 000 598.
Surprisingly it has been found that by providing a fastening tab with a transferrable mechanical fastening patch including male fastening elements (rather than loop material) that a tab is obtained that in conjunction with a diaper or incontinence brief has a greater degree of adjustability and/or ease in use. This is particularly surprising since although loop-transfer tabs have been commercially known and used since at least a decade, the application of fastening tabs including a transferrable patch of male fastening elements has not been commercially explored. Furthermore, it has been found that the overall construction of such tabs can be simplified in comparison to known loop transfer tabs, in particular so simplified that desirably stable rolls of fastening tapes towards production of such tabs can be provided.
Accordingly, in one aspect of the present invention there is provided a fastening tab comprising a proximal end and a distal end. The proximal end comprises a backing including a first major surface and a second major surface, wherein said first major surface is provided with a release surface (such as a low surface energy film, a microstructured film, or a low adhesion backside coating), wherein the fastening tab further comprises a mechanical fastening patch, said patch comprising on one side male fastening elements and on the opposite side an adhesive, wherein the patch is releasably attached to the release surface via the adhesive. The distal end comprises a backing including a first major surface and a second major surface, wherein said first major surface has a structure or is provided with a structure that is adapted to be engaged by said male fastening elements of the patch.
To further facilitate greater degrees of adjustability and/or ease in use, it has been found advantageous to provide tabs wherein the width of the engaging-structure (e.g. having regard to the transverse direction of the tab from the proximal end to the distal end) is favorably at least 2 times greater than the width of the male fastening element comprising patch, more favorably the width of the engaging-structure is at least 2.5 times greater than the width of the of male fastening element comprising patch, most favorably the width of the engaging-structure is at least 3 times greater than the width of the of male fastening element comprising patch.
Desirably the proximal and distal ends of the tab are configured and arranged such that at least a portion of one end (in particular the distal end) can be folded onto the other end (in particular the proximal end) so that said male fastening elements can releasably engage said engaging-structure.
Desirably the fastening tab is configured and arranged, such that the force to disengage the male fastening elements from the engaging-structure is higher than the force to detach the adhesive of the male fastening element patch from the release surface (such as a low adhesion backside). It will be recognized that through the use of the release surface (e.g. a low adhesion backside), favorably the force to detach the adhesive of the male fastening element comprising patch from the release surface will be typically low, thus facilitating the desirable configuration and arrangement towards a fastening tab where the force needed to disengage the male fastening elements from the engaging-structure will be higher.
The adhesive of the male fastening element comprising patch, referred to in part in the following as the first adhesive, is favorably a pressure sensitive adhesive, more favorably pressure sensitive adhesives based on styrene-isoprene-styrene block copolymer/tackifier mixtures. First adhesives may have a coating weight in the range of 20 to 50 g/m2. Alternatively or additionally, First adhesive may have a thickness in the range of 20 microns to 60 microns.
As described in more detail below, when using fastening tabs as described herein with absorbent articles, the male fastening element patch will be moved from the tab to the absorbent article, such that the first adhesive will be adhered to a portion of the absorbent article, e.g. the front waist portion of a diaper or an incontinence brief. Desirably the fastening tab is configured and arranged, such that the force to detach the first adhesive of the transferred male fastening element patch from the absorbent article is greater than force needed to disengage the male fastening elements from the engaging-structure. In regard to the latter, it will be appreciated by the skilled reader that forces needed to disengage common commercial “hook-and-loop” pairings are typically around 5 N/25 mm.
Favorably the first adhesive has a 90° peel adhesion to a smooth polyethylene test surface having an average surface roughness value Ra of about 1.4 μm and an average peak to valley height value Rz of about 12.5 μm greater than 5 N/25 mm, in particular equal to or greater than 6 N/25 mm, more particularly equal to or greater than 7 N/25 mm e.g. as measured according to FINAT Test Method No. 2 “Peel Adhesion (90°) at 300 mm per minute” in 5th Edition FINAT Technical Handbook (Test Methods) 1999 using an automatic roller with a roll-down weight of 5,000 g and roller speed 5 mm/sec, where after placing the sample to be tested on the polyethylene test surface, the sample is rolled down once in each direction . Within the aforesaid range, while first adhesives having 90° peel adhesions greater than 15 N/25 mm may be used, generally first adhesives having 90° peel adhesions up to and including 15 N/25 mm are suitable. In addition or alternatively, the first adhesive favorably has a tack value to a smooth polyethylene test surface having an average surface roughness value Ra of about 1.4 μm and an average peak to valley height value Rz of about 12.5 μm equal to or greater than 5 N/25 mm, in particular equal to or greater than 6 N/25 mm, more particularly equal to or greater than 7 N/25 mm e.g. as measured according to FINAT Test Method No. 9 “‘Loop’ tack measurement” in 5th Edition FINAT Technical Handbook (Test Methods) 1999. It will be appreciated that samples tested in the aforesaid peel adhesion and/or tack test method comprise the first adhesive as provided on the male fastening element comprising patch (e.g. first adhesive on one major surface of the sample to be tested and male fastening elements on the opposite major surface thereof).
Desirably the second major surface at the proximal end is provided at least in part with a second adhesive. The second major surface at the distal end may also be provided at least in part with a third adhesive. In the event, second and third adhesives are provided they may be identical or different. The backing of the proximal end and the backing of the distal end may be either integral or two separate elements, wherein in the latter case the two separate elements are favorably connected to another via a connection member.
The male fastening elements are favorably selected from the group consisting of hook fasteners, mushroom-shaped fasteners, stem-shaped fasteners, cup-shaped fasteners, T-shaped fasteners and mixtures thereof.
The engaging-structure may comprise a structure selected from the group consisting of nonwoven structures, loops, mushroom-shaped fasteners, cup-shaped fasteners, T-shaped fasteners and mixtures thereof.
In another aspect of present invention there is provided a fastening tape comprising a plurality of fastening tabs as described herein, wherein the fastening tabs are arranged in an endless form on the tape so that individual fastening tabs can be provided from the fastening tape by cutting the tape across its width. In a further aspect of the present invention there is a provided a roll of such fastening tape.
Desirably, the proximal and distal ends of the fastening tabs are configured and arranged in the roll such that said male fastening elements are not engaging said engaging-structure. In other words, the fastening tape is desirably rolled in a flat, unengaged (e.g. unfolded) configuration. Moreover relative to the width of the tape as provided in the roll, the proximal and distal ends of the fastening tabs are positioned favorably in two outer lateral regions of rolled fastening tape. This is advantageous in that across the width of the tape the overall height of the tape on the roll is relatively low (e.g. in comparison to known loop transfer tapes where the loop and hooks are typically provided in engaging (e.g. folded) configuration) and the highest elements in the outer two lateral regions of the rolled tape (in other words the male fastening elements and the engaging-structure in the proximal and distal ends, respectively, of the endless configured fastening tabs on the tape) are not too dissimilar in height; both of the aforesaid contributing favorably to the provision of stable rolls.
The ends of the male fastening elements which are distal to the first adhesive (i.e. those ends of the male fastening elements typically involved in the releasable engagement to the engaging-structure) are favorably positioned in the roll towards the second major surface at the proximal end. For those embodiments wherein the second major surface at the proximal end is provided at least in part with a second adhesive and said ends of the male fastening elements are in contact with said second adhesive in the roll, this will further facilitate the stability of the roll, and surprisingly without detrimentally effecting the unwinding of the roll. Moreover, it has been observed even if the force (e.g. peel force) to disengage said ends of the male fastening elements from the second adhesive is higher than the force needed to detach the first adhesive of the male fastening element patch from release surface (which is normally the case), the roll can be unwound without the first adhesive and release surface peeling apart. Without wanting to be bound to a particular theory, this seems to be due to a combination of factors: one being that the tabs are arranged in an endless form on the roll and thus there is no leading edge from which a peeling of the first adhesive from the release surface can be initiated, and another being that the ends of individual male fastening elements that are in contact with second adhesive typically have edges from which a peeling of male fastening elements from the second adhesive can be initiated.
Accordingly rolls described herein are favorably free of a release liner between the male fastening elements and the second major surface at the proximal end, and in particular for those embodiments having a second adhesive at the proximal end, are free of a release liner between the male fastening elements and the second adhesive provided on said second major surface at the proximal end. This is particularly advantageous in light of known loop-transfer tapes which commonly employ a release liner in the roll. Rolls are also favorably free of a release liner between the engaging-structure and the second major surface at the distal end, and in particular for those embodiments including a third adhesive at the distal end, are free of a release liner between the engaging structure and the third adhesive provided on said second major surface.
In a further aspect of the present invention, there is provided an absorbent article, in particular a diaper or an incontinence brief, comprising a back sheet, a top sheet and an absorbent core there between and a fastening tab as described herein, wherein the fastening tab is attached to the absorbent article at least its proximal end.
For absorbent articles that are diapers and incontinence briefs, fastening tabs may be attached to a rear waist portion or alternatively for absorbent articles comprising an ear or ears, at a distal end portion of the ear(s), more particularly to the inside of the rear waist portion or to the inside of the ear(s), respectively.
Favorably prior to use by the user, e.g. in the packaged and/or storage condition of the absorbent article, the fastening tab is folded so that the male fastening elements are releasably engaged with the engaging-structure, more favorably the distal end of the fastening tab is folded onto the proximal end of the fastening tab so that the male fastening elements are releasably engaged with the engaging-structure.
As mentioned above, as the result of the use of a release surface in the proximal end of the fastening tab, typically the force to detach the adhesive of the patch from the release surface is lower, in particular much lower, than the force to disengage the male fastening elements from the engaging-structure. This means that starting from for example the favored packaged configuration of an absorbent article, e.g. a diaper or an incontinence brief, where the fastening tab is folded and the male fastening elements are releasably engaged with the engaging-structure, when the user unfolds the fastening tab, the adhesive of the patch will detach from the release surface while the male fastening elements of the patch remain releasably engaged with the engaging-structure at the distal end of the tab. Accordingly the patch with its engaged fastening elements is transferred from the proximal end onto the distal end of the fastening tab and additionally the adhesive of the patch is now exposed.
After this first unfolding, the user can then close the absorbent article, e.g. a diaper or an incontinence brief, by pressing the distal end of the fastening tab onto a respective (e.g. appropriate) portion of the absorbent article, so that the adhesive of the patch adheres to the respective portion of the absorbent article. For example for absorbent articles that are diapers or incontinence briefs, the adhesive of the patch can be adhered e.g. on a front waist portion, in particular on the outside of the front waist portion. Upon this first closure the adhesive of the patch with its male fastening elements will be advantageously affixed onto the absorbent article, i.e. onto said respective portion of the absorbent article. Thus in this sequence of unfolding and first closure, the patch has been transferred from the proximal end to the distal end of the fastening tab and subsequently from the distal end of the fastening tab onto the respective portion of the absorbent article.
Furthermore, it will be recognized that after the aforementioned second transfer, the patch and the fastening tab will favorably function like a regular mechanical-based closure system. Moreover upon the user pulling the fastening tab to open the absorbent article, the engaging-structure at the distal end of the fastening tab will disengage from the fastening elements of the patch, while the patch remains adhered to the absorbent article. Thereafter the user may then reclose the absorbent article by pressing the distal end of the fastening tab onto the patch such that the engaging-structure at the distal end of the fastening tab releasably (re-)engages the fastening elements of the patch.
It is to be understood that the present invention covers all combinations of particular, suitable, desirable, favorable advantageous and preferred aspects of the invention described herein.
The invention will now be described with reference to the following drawings.
In the description that follows, unless expressly stated otherwise, terms such as ‘top’, ‘bottom’, ‘above’, ‘below’, etc, refer only to features as shown in the Figures, and no restriction as to orientation of use, etc, is intended. Not all Figures are to the same scale.
In the exemplary embodiment depicted in
Adhesives suitable for use as second and/or third adhesives include pressure sensitive adhesives, more favorably pressure sensitive adhesives based on styrene-isoprene-styrene block copolymer/tackifier mixtures. Second and/or third adhesives may have coating weights in the range of 20 to 50 g/m2. Alternatively or additionally, second and/or third adhesives may have thicknesses in the range of 20 microns to 100 microns.
Second and/or third adhesives, like first adhesives, may favorably have a 90° peel adhesion to a smooth polyethylene test surface having an average surface roughness value Ra of about 1.4 μm and an average peak to valley height value Rz of about 12.5 μm greater than 5 N/25 mm, in particular equal to or greater than 6 N/25 mm, more particularly equal to or greater than 7 N/25 mm e.g. as measured according to FINAT Test Method No. 2 “Peel Adhesion (90°) at 300 mm per minute” in 5th Edition FINAT Technical Handbook (Test Methods) 1999 using an automatic roller with a roll-down weight of 5,000 g and roller speed 5 mm/sec, where after placing the sample to be tested on the polyethylene test surface, the sample is rolled down once in each direction. Within the aforesaid range, while second and/or third adhesives having 90° peel adhesions greater than 15 N/25 mm may be used, generally 90° peel adhesions up to and including 15 N/25 mm are suitable.
In the peel adhesion and loop tack testings mentioned herein, the polyethylene test surface may be provided by adhering (e.g. via double sided tape) an appropriate polyethylene film onto a (e.g. glass or stainless) test plate. Such a polyethylene film may be obtained as follows: A low density polyethylene resin (such as the low density resin marketed under the trade designation TENITE 1550P by Eastman Chemical Co. Kingsport, Tenn.) having a melt index of 3.5 grams/10 min and a density of 0.918 grams/cm is extruded at a melt temperature of 182° C. vertically downward through a conventional coat-hanger slot extrusion die. The melt exiting the die is drawn into a nip formed by a mirror finish chrome roll (8° C. inlet water temperature) and a silicone rubber roll (7° C. inlet water temperature) resulting in a film of 330 microns thickness, whereby the surface of the film that was in contact with the chrome roll will be that surface of the film that used for testing. Said surface typically has an average surface roughness value Ra of 1.4 μm and an average peak to valley height value Rz of about 12.5 μm as measured using a laser profilometer (e.g. a laser profilometer model number UB-16 available from UBM Messtechnik GmbH, Ettlingen, Germany) and computed in accordance with Deutsche Industrie Norm (DIN) 4768 and DIN 4762.
In alternative embodiments, the second major surface at just the proximal end may be provided with an adhesive for affixing the tab onto an absorbent article. Such an embodiment in depicted in
As indicated supra, the present invention further relates to tapes comprising a plurality of fastening tabs as described herein as well as rolls of tapes comprising a plurality of fastening tabs. An exemplary embodiment of such tape and roll is shown in
The backing of fastening tabs described herein may be selected from a variety of films or sheetings including single-layered and multi-layered films, co-extended films, laterally laminated films or films comprising film layers. The layers of such films or sheetings may comprise various materials such as, for example, polypropylene, polyvinylchloride, polyethylene terephthalate, polyethylene, polyolefin copolymers or blends of polyolefins such as, for example, a blend of polypropylene, low density polyethylene and/or linear low density polyethylene, textiles, and non-woven and foamed materials. In alternate embodiments, the backing of fastening tabs described herein may be selected from a variety of fibrous webs, including wovens, knitted webs or nonwovens. For embodiments including a fibrous web as a backing and a second and/or third adhesive, the backing may be poly-coated to minimize penetration of adhesive into the backing. Fibrous-web-backings (e.g. nonwoven backings) may be favorably selected such that the male fastening elements can releasely engage directly the first major surface of the backing, i.e. said first major surface has an inherent structure that can be releasably engaged by said male fastening elements of the patch.
The thickness of the backing is favorably between 30 microns and 500 microns, and more favorably between 40 and 150 microns. The basis weight of the backing is favorably between 15 and 500 g/m2, more favorably between 20 and 300 g/m2 and particularly favorably between 20 and 200 g/m2. It will be appreciated by the skilled reader that for a particular basis weight, the thickness of a nonwoven backing will generally greater than a film backing. Having regard to the aforesaid favorable basis weights for backings, nonwoven backings most favorably have basis weights between 35 and 85 g/m2.
Substantially any thermoplastic materials suitable for film production can be used to produce the one or more patches of fastening material. Preferred thermoplastic resins include polyesters, such as poly (ethylene terephthalate); polyamides, such as nylon; poly (styrene acrylonitrile); poly (acrylonitrile butadiene styrene); polyolefins, such as polypropylene and/or polyethylene; and plasticized polyvinylchloride.
The male fastening elements may comprise male fastening elements selected from the group consisting of hook fasteners, mushroom-shaped fasteners, stem-shaped fasteners, cup-shaped fasteners, T-shaped fasteners and mixtures thereof. Male fastening elements usually comprise a stem supported by the exposed major surface of a patch of fastening material and an enlarged section which is positioned at the end of the stem opposite to the exposed major surface. The fastening elements can also be formed by stem having no enlarged section at the end of the stem, wherein such stems are preferably essentially conical, cylindrical or pyramidal. Fastening elements suitable in the present invention can be manufactured from a wide range of materials including thermoplastic polymers such as, for example, nylon, polyester, polyolefins (e.g. polypropylene and/or polyethylene) or any combination of these. The fastening elements preferably comprise the material of which the patch of fastening material is formed. The height of the fastening elements may range from 0.1 to 0.4 mm.
Engaging-structures suitable in the present invention can be manufactured from a wide range of materials including thermoplastic polymers such as, for example, nylon, polyester, polyolefins (e.g. polypropylene and/or polyethylene) or any combination of these. As will be described in more detail below, the proximal and distal ends of the tab are advantageously configured and arranged such that at least a portion of one end (in particular the distal end) can be folded onto the other end (in particular the proximal end) so that said male fastening elements can releasably engage said engaging-structure. Depending on the particular male fastening elements used, the engaging-structure may comprise a structure selected from the group consisting of nonwoven structures, loops (e.g. knitted loops, woven loops, extrusion bonded loops), mushroom-shaped fasteners, cup-shaped fasteners, T-shaped fasteners and mixtures thereof. The height of engaging-structure may range up to 0.4 mm.
Desirably, the fastening tab is configured and arranged, such that the force to disengage the male fastening elements from the engaging-structure is higher than the force to detach the adhesive of the fastening element patch from the release surface.
In particular,
Absorbent articles including at least one fastening tab as described herein wherein the distal end of the fastening tab is folded onto the proximal end of the fastening tab so that the male fastening elements are releasably engaged with the engaging-structure are preferred for storage and/or product packaging purposes. Accordingly an advantageous method of manufacturing such an absorbent article, in particular a diaper or incontinence brief, comprises the steps of: a) providing an absorbent article comprising a back sheet, a top sheet, and an absorbent core therebetween; b) providing at least one fastening tab as described herein; c) affixing the at least one fastening tab with at least its proximal end to the absorbent article; and d) folding the distal end of the at least one fastening tab onto the proximal end of the at least one fastening tab so that the male fastening elements are releasably engaged with the engaging-structure.
Methods of using such an absorbent article advantageously comprise the steps of: a) unfolding the distal end of the fastening tab so that the adhesive of the patch detaches from the release surface (e.g. low adhesion backside) and the male fastening elements of the patch remain engage with the engaging-structure, and b) closing the absorbent article by pressing the distal end of the fastening tab onto a respective portion of the absorbent article, thereby affixing the adhesive of patch (i.e. the first adhesive) to said respective portion of the absorbent article. This is best understood by making reference to
In particular
It will be further appreciated that the re-opening and re-closing of the absorbent article is advantageously possible. Favorable methods of use comprise the further step of: opening the absorbent article by pulling the distal end of the fastening tab so that the engaging-structure of the fastening tab disengages from the male fastening elements of the patch while the patch remains affixed to respective portion of absorbent article. Such favorable methods of use comprise more favorably the additional step of: re-closing the absorbent article by pressing the distal end of the fastening tab onto the patch so that the engaging-structure of fastening tab releasably engages the fastening elements of the patch.
This is best understood by making reference to
Number | Date | Country | Kind |
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14176556.0 | Jul 2014 | EP | regional |
Filing Document | Filing Date | Country | Kind |
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PCT/US2015/039669 | 7/9/2015 | WO | 00 |