Patent Application
20200323710
The present disclosure pertains to a pant-type absorbent article with a disposal tape. The present disclosure also pertains to a method of permanently attaching a disposal tape to the outer cover of a pant-type absorbent article.
Disposable absorbent articles are designed to receive and contain body exudates or fluids such as urine. The absorbent articles are configured for single use and comprise a liquid permeable topsheet, an outer cover and an absorbent core arranged between the topsheet and the outer cover.
The disposable absorbent articles should be comfortable during use, while being worn, and it may be desired that the absorbent articles have cloth-like and soft appearance as close to regular underwear as possible. For disposable pant-type diapers, the outer cover may often be folded inwardly over the waist edge and is therefore in direct contact with the skin of the wearer and it may therefore be of an advantage to have a soft and cloth-like nonwoven as the outermost material layer on the outer cover.
Disposable pants-type diapers may be provided with various types of disposal tape arrangements to secure a rolled-up garment, and thereby enable easy and hygienic disposal of the diaper. Such disposal tape may be a longitudinally extending fastening tape having an adhesive section releasably bonded to the outer cover of the diaper. The upper end or lower end of the tape is permanently bonded to the outer surface of the garment. The disposal tape can be stretched after peeling a portion of the tape from the base, and then wrapped around the diaper to secure the diaper in a rolled-up configuration for easy disposal. During use of the diaper, rubbing and chafing against clothes of the user may result in detachment of the disposal tape edges, or corner portions, if the attachment of the disposal tape to the outer cover is not sufficient, which gives a negative impression on the quality of the diaper upon disposal, partial detachment of the disposal tape from the outer cover may occur upon unfolding and pulling in the disposal tape when wearer or care giver are wrapping the disposal tape around the rolled up diaper.
The present disclosure offers an improved permanent attachment of the disposal tape to the outer cover of pant-type absorbent articles and a method for permanently attaching the disposal tape to the outer cover of pant-type absorbent articles.
The present disclosure relates to a pant-type absorbent article such as a pant diaper, a sanitary pant or incontinence pant. The article comprises an outer cover being disposed on a garment facing side of the absorbent article and the article further has a front portion, a back portion and a crotch portion therebetween. The absorbent article furthermore comprises an absorbent core arranged in the crotch portion on a wearer facing side of the outer cover. The outer cover comprises a nonwoven fibrous material on a garment-facing side thereof and a disposal tape comprising a tape adhesive zone is permanently attached at the tape adhesive zone to the outer cover in an attachment zone on the nonwoven fibrous material of the outer cover in the back portion of the article. The disposal tape has a folded pre-disposal configuration and an unfolded disposal configuration. The outer cover attachment zone is constituted by a modified portion of the nonwoven fibrous material, wherein a bond strength between the tape adhesive zone and the modified attachment zone is greater than a bond strength between the tape adhesive zone and a non-modified portion of the nonwoven fibrous material.
The term “absorbent article” refers to products that are placed against the skin of the wearer to absorb and contain body exudates, like urine, faeces and menstrual fluid. The disclosure furthermore refers to disposable absorbent articles, which means articles that are not intended to be laundered or otherwise restored or reused as an absorbent article after use. The disclosure refers to “disposable pant-type absorbent articles”, having an outer cover being disposed on a garment facing side of the absorbent article and an absorbent core arranged in the crotch portion on a wearer facing side of the outer cover. Examples of such pant-type absorbent articles are pant diapers, sanitary pants and incontinence pants.
By “permanently attached” refers to the attachment of two elements, herein a nonwoven fibrous material to a disposal tape, such that the elements tend to be and remain bonded during normal use conditions of the absorbent article, such as for example that the disposal tape is permanently attached to the nonwoven fibrous material with such adhesion that the tape withstands a load of at least 25 N in a gripping end of the disposal tape without the tape coming away from the nonwoven fibrous material.
The pant-type absorbent article comprises an outer cover, the outer cover may be elastic, and may comprise an elasticized waist portion, such as comprising elastic members, such as elastic threads, affixed between the outer cover garment facing nonwoven material and a further material layer provided on a wearer facing side of the nonwoven material. The outer cover may also comprise an elastic laminate, such as for example elastic laminate comprising an elastic film which on opposite sides is bonded to first and second non-elastic fibrous nonwoven material. The laminate is made by bonding the non-elastic fibrous nonwoven materials to the elastic film layer and subsequently stretching the composite material. The elastic film material may be of a breathable material.
The modified attachment zone may be a heat-treated zone, such as a heat-treated zone formed by means of heat embossing, ultra sound, heated air or IR. The heat treatment of the nonwoven fibers results in that the polymeric material in the nonwoven fibers softens and/or melts and thereby modifies the nonwoven surface.
The modified attachment zone may be a compressed area, such as a compressed zone formed by means of embossing, such as by a stamp or by a roller. The compression of the nonwoven fibrous material compresses and flattens the nonwoven material which provides a bonding surface.
The modified attachment zone may have a modified cross-section appearance, such that the nonwoven fibers are at least partly consolidated or flattened within the attachment zone. Such modification may be formed by heat-treating and/or compressing and modifying the attachment zone such that the bond strength to the disposal tape adhesive zone is improved. A combination of heat and compression may be achieved using heated rollers and heat embossing, which softens and/or melts the polymeric material in the nonwoven while also providing pressure to provide a flattened surface.
The modified attachment zone may be a plasma-treated zone, such as atmospheric pressure plasma, or a corona-treated zone. Plasma and corona treatments increase the bond strength between the nonwoven outer cover and the disposal tape by modifying the surface of the nonwoven.
A plasma treatment modifies the nonwoven fiber surface on a nano-scale by changing the chemical structure of the fiber. Plasma is an outwards neutral, partially ionized gas, the composition of which depends on the gas used in the formation of plasma. Gas molecules are ionized in an electric field through electron impacts, and the ionized, highly reactive species, such as ions, electrons and radicals, modify the surface of the nonwoven material. Plasma treatments provide a permanent surface modification.
Corona treatments use a low corona discharge to impart changes in the properties of the nonwoven surface. The surface modification provided by the corona treatment is not permanent.
The outer cover may be a laminate of the nonwoven fibrous material and at least one further material layer, such as a nonwoven material and/or a thermoplastic film.
The laminate may have a lamination bonding area of from 5 to 100%. The laminate may be bonded be means of adhesive slot bonding or spray coating. Optionally, the laminate bonding area may be below 100%, such as from 5% to 95%.
The nonwoven fibrous material may comprise a plurality of discrete bonds, such as thermal bonds, and the cumulated surface area of the discrete bonds may be in the range of from 1% to 25% of the total surface area of the nonwoven fibrous material, such as from 5% to 25% of the total surface area of the nonwoven fibrous material. It has been found that nonwoven materials having a low cumulated area of discrete bonds provide a soft and underwear-like appearance to the nonwoven material. The discrete bonds may further have a distance to adjacent discrete bonds of at least 2 mm, or at least 4 mm, the distance being measured from edge to edge of the discrete bonds. The nonwoven fibrous material may furthermore be treated with a melt additive to increase the softness of the nonwoven material, examples of such melt additives are polyolefin waxes and primary and secondary amides, such as erucamide, oleamide and stearyl derivatives. However, the fact that the nonwoven material is soft and fluffy renders it more difficult to attach the disposal tape to the nonwoven fibrous material. A problem also noticed by the present inventors in connection with absorbent articles having softer nonwoven fibrous materials as outer covers, is that the bond strength between a softer nonwoven material and a disposal tape is not strong enough, which may lead to partial detachment of the disposal tape when using it for wrapping the used absorbent article.
The nonwoven fibrous material may thus be a soft nonwoven fibrous material, for example a spunbond nonwoven material, a laminate of a spunbond-meltblown-spunbond material. The nonwoven fibrous material may be a carded nonwoven material and the nonwoven fibrous material may be a through-air-bonded nonwoven material. To increases the softness of the nonwoven fibrous material, the nonwoven materials may have a low cumulative area of thermal discrete bonds.
The nonwoven fibrous material may have a higher bond area in the modified attachment zone than in the non-modified portion of the nonwoven fibrous material.
The cumulated surface area of the bonds in the modified attachment zone may be at least 30%, such as from 30% to 85%, of the total surface area of the modified attachment zone.
For an absorbent article comprising an elastic outer cover, there may also exist a need for a strong attachment between the outer cover nonwoven material and the disposal tape as the wrinkles resulting from the elastic outer cover may result in weaker bonding of the disposal tape and/or increased risk of the disposal tape outer edges to detach from the outer cover.
The disposal tape may have an outer circumferential edge in the folded pre-disposal configuration and the outer cover attachment zone may have an outer circumferential edge. The outer cover attachment zone may extend to or beyond the outer circumferential edge of the disposal tape when arranged in the unfolded pre-disposal configuration. The outer cover attachment zone may extend beyond the outer circumferential edge of the disposal tape by at least 1 mm, or at least 2 mm, or at least 5 mm.
The fact that the outer cover attachment zone may extend to or beyond the outer circumferential edge of the disposal tape provides higher bond strength between the nonwoven fibrous material and the disposal tape at the circumferential edge of the disposal tape which prevents the outer edges to loosen from the nonwoven fibrous material which may cause the disposal tape to get caught in the wearer clothing and result in premature unfolding of the disposal tape.
The attachment zone may be modified in an intermittent pattern or in a continuous pattern covering entirely the outer cover attachment zone.
The disposal tape may be rectangular and may be z-folded when in the pre-disposal configuration.
The disposal tape comprises or consists of a thermoplastic film.
The disposal tape may be permanently attached to the attachment zone by means of an adhesive. The adhesive may for example be a pressure-sensitive hot melt (PSHM) adhesive.
The disposal tape may have a length and a width in the unfolded configuration and, the width may be in the range from 5 to 30 mm, such as from 12 to 20 mm. It has been discovered by the inventors that a disposal tape having width of at least 5 mm, such as at least 12 mm, and being adhered adhesively to an outer cover nonwoven fibrous material being modified according to the present disclosure gives a significantly improved attachment of the disposal tape.
The present disclosure also pertains to a method of permanently attaching a disposal tape to an outer cover of a pant-type article, comprising:
The attachment zone may be modified by one or more of the following treatments; a heat or cold embossing, ultra sound, plasma charges, such as corona treatment, heated air and/or infrared radiation.
The step c) of producing an absorbent article may include elastifying the outer cover by means of elastic elongated elements or an elastic material or wherein the wherein the nonwoven fibrous material is an elastic nonwoven fibrous material, providing an at least partly elastic outer cover and wherein the elastic outer cover is stretched during the zone modification step a) and the disposal tape attachment step b).
The modification step a) may comprise a step of simultaneous heat and compression treatment, such as by heat embossing, for example by a heated roller or a heated stamp.
The fact that the modification step may be carried out with a simultaneous heat and compression treatment provides an improved bond strength between the tape adhesive zone and the modified attachment zone without the need to use too high temperatures or too high pressures, which could otherwise risk to impair the nonwoven fibrous material or require heating of the compression tool to high temperatures resulting in high energy consumption in order to obtain a desired modified nonwoven fibrous structure. Such modification may result in that the nonwoven fibers in the modified attachment zone are at least partly consolidated and flattened.
The modification step a) may comprise modifying a zone on the nonwoven fibrous material with heat treatment, and step b) is performed immediately after step a) while the modified attachment zone still has a temperature above the temperature of a non-modified portion of the nonwoven fibrous material.
The present disclosure will be further explained hereinafter by means of non-limiting examples and with reference to the appended drawings wherein:
It is to be understood that the drawings are schematic and that individual components, such as layers of materials are not necessarily drawn to scale. The pant-type absorbent article shown in the figures are provided as examples only and should not be considered limiting to the disclosure. Accordingly, the scope of the invention is determined solely by the scope of the appended claims.
The outer cover 2 may however also be formed of a continuous outer nonwoven fibrous material 4 extending over the outer cover main portion 2a, the front portion 2b and the back portion 2c. The outer cover 2 may be reinforced in the outer cover main portion 2a extending over the crotch area of the wearer, with a breathable or non-breathable polymeric film or with a film/nonwoven laminates.
Examples of breathable materials are microporous polymeric films, nonwoven laminates from spunbond and meltblown layers, laminates from microporous polymeric films and nonwoven materials. In the absorbent core 25 area, covering the absorbent core, outer cover 2 may comprise a liquid impervious film layer, such as a thin thermoplastic film, e.g. a polyethylene or polypropylene film. The liquid impervious film layer covers at least the absorbent core 25 on the garment-facing side of the pant diaper 1.
The liquid permeable topsheet 24 can be any suitable topsheet material as known by the person skilled in the art and may be fibrous topsheet material composed of a nonwoven material, e.g. spunbonded, meltblown, carded, hydroentangled, wet laid etc. Suitable nonwoven materials can be composed of natural fibers, such as woodpulp or cotton fibres, synthetic thermoplastic fibres, such as polyolefins, polyesters, polyamides and blends and combinations thereof or from a mixture of natural and synthetic fibres. Further examples of topsheet materials are porous foams. The materials suited as topsheet materials should be soft and non-irritating to the skin and be readily penetrated by body fluid, such as urine or menstrual fluid. The topsheet material may be essentially constituted of non-absorbent fibers, such as synthetic thermoplastic fibers, such as such as polyolefins, polyesters, polyamides and blends and combinations thereof. The synthetic fibers may be mono component fibers, bicomponent fibers or multicomponent fibers including polyesters, polyamides and/or polyolefins such as polypropylene and polyethylene.
The disposable absorbent article in this disclosure includes an absorbent core 25, provided on a wearer-facing side of the outer cover. The absorbent core 25 may be of any conventional kind and of any useful size and shape. Examples of commonly occurring absorbent materials are cellulosic fluff pulp, tissue layers, highly absorbent polymers (so called superabsorbents), absorbent foam materials, absorbent nonwoven materials or the like. It is common to combine cellulosic fluff pulp with superabsorbents in an absorbent structure. It is also common to have absorbent structures including layers of different material with different properties with respect to liquid acquisition capacity, liquid distribution capacity and storage capacity. This is well-known to the person skilled in the art and does therefore not have to be described in detail. The thin absorbent bodies, which are common in today's sanitary articles, often include a compressed mixed or layered structure of cellulosic fluff pulp and superabsorbent. The size and absorbent capacity of the absorbent structure may be varied to be suited for different uses such as, adult incontinence pants and baby pant diapers.
In
The pant diaper 1 in
The nonwoven fibrous material 4 may be a soft nonwoven fibrous material 4, for example a spunbond nonwoven material, a laminate of a spunbond-meltblown-spunbond material. The nonwoven fibrous material may be a carded nonwoven material and the nonwoven fibrous material may be a through-air-bonded nonwoven material. Nonwoven fibrous materials having a low cumulated area of discrete thermal bonds have been found to have improved softness. The discrete thermal bonds may be located in a sparse pattern including discrete bonds having a distance to adjacent bonds of at least 2 mm, or at least 4 mm, the distance being measured between edge to edge of the discrete bonds. The cumulated surface area of the bonds may be in the range of from 1% to 25% of the total surface area of the nonwoven material 4. The nonwoven material 4 may furthermore be treated with a melt additive to increase the softness of the nonwoven material 4.
A disposal tape 10 is attached to the nonwoven fibrous material 4 of the outer cover 2 in the back portion 8 of the pant diaper 1. The disposal tape 10 is attached to the pant diaper 1 with an adhesive, in a folded pre-disposal configuration. The adhesive may for example be a pressure sensitive hot melt (PSHM) adhesive. The disposal tape 10 may for example comprise or consist of a thermoplastic film, such as a polyolefin film. The disposal tape 10 has an outer circumferential edge 15 in the folded pre-disposal configuration.
The bond strength may be measured with any method relevant for measuring the bond strength between the tape adhesive zone 12 and the modified attachment zone 13 and comparing it with bond strength between the tape adhesive zone 12 and the non-modified portion 14 of the nonwoven fibrous material.
The modification of the nonwoven fibrous material 4 and the attachment of the disposal tape 10 to the nonwoven fibrous material 4 may optionally be performed prior to assembly of the pant diaper 1. The nonwoven fibrous material 4 may be provided in the form of a continuous nonwoven fibrous material web and by modifying zones on the continuous nonwoven fibrous material web with a predefined distance between the zones. The modification may be achieved, as set out herein, by means of heat treatment, plasma treatment, by compressing said zone or a combination of two or more of said treatments to provide the modified attachment zone 13. In a subsequent step a disposal tape 10 may be attached to each modified attachment zone 13. The disposal tape 13 is attached at the tape adhesive zone 12, provided with an adhesive layer, to the nonwoven fibrous material 4 by pressing and thereby bonding the tape adhesive zone 12 to the modified attachment zone 13. The modification of the nonwoven and the attachment of the disposal tapes may be performed either in a separate production step, such that the nonwoven material may be delivered to the pant-type diaper assembly line in rolls with the disposal tapes already attached to the modified attachment zones at predefined and repeated locations, or alternatively when producing pant-type absorbent articles on a continuous production line, prior to, during or after the assembly of the pant-type absorbent article.
As illustrated in
The disposal tape 10 may comprise a first tape 22 and a second tape 11 attached to the outer cover 2, the first tape 22 comprising a first tape reinforcing section 22a and a first tape connection section 22b being attached to the second tape 10, such disposal tape configuration having an T-shaped attachment configuration when the disposal tape 10 is in an unfolded disposal configuration provides an improved attachment to the nonwoven fibrous material 4.
Measurement of adhesive strength between disposal tape and backsheet material.
A method was used to determine the adhesive strength between the disposable tape and the backsheet nonwoven material of a diaper when subjected to a defined pulling speed in a tensile tester. The test was conducted at least 24 hours after the product had been manufactured and packed in a bag. An Instron tensile tester with a 50 or 100 N load cell connected to a computer running suitable software was used for the test. The back-waist part of the diaper was secured in a fixture, specially designed for the method, in the Instron tensile tester. The tensile tester pulled the tape at 300 mm/min in a 90° angle and registered the maximum force generated during the test. One test series with disposal tape adhered with glue on a heat-treated zone on the backsheet nonwoven material of the diaper according to the present disclosure and one test series of reference sample glued directly to the backsheet nonwoven material were tested. The result is shown in Table 1. From the result, it is evident with a confidence interval of 95%, that the modified zone of the backsheet nonwoven material according to the present disclosure increased the bonding strength to the disposal tape considerably.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/080539 | 11/27/2017 | WO | 00 |
