An absorbent hygienic article for absorbing body fluids

Abstract

The present invention relates to an absorbent hygienic article (10) for absorbing body fluids The absorbent hygienic article comprises a topsheet (12), an acquisition distribution layer (14), an absorbent core (16) and a backing layer (18), wherein the acquisition distribution layer is arranged between the topsheet and the absorbent core. The topsheet is a nonwoven material comprising cellulose-based fibres. The acquisition distribution layer is a nonwoven material comprising continuous filaments made of regenerated cellulose, which continuous filaments are multibonded by a combination of merged filaments, hydrogen bonding and physical intermingling of the filaments. The invention further relates to a method of manufacturing the absorbent hygienic article.

Description

[0001] AN ABSORBENT HYGIENIC ARTICLE FOR ABSORBING BODY FLUIDS

[0002] TECHNICAL FIELD

[0003] The invention pertains to an absorbent hygienic article for absorbing body fluids, which absorbent hygienic article comprises a topsheet, an acquisition distribution layer, an absorbent core and a backing layer. The invention further relates to a method of manufacturing the absorbent hygienic article.

[0004] BACKGROUND

[0005] In the field of disposable absorbent hygienic articles such as disposable sanitary napkins, diapers, incontinence pads, and the like, which are thrown away after a single use, it is a rising concern to minimize the environmental impact of such absorbent hygienic articles. Hence, it is a desire that disposable hygienic articles may be manufactured using a minimum of non-renewable, e.g. oil-based, polymeric materials.

[0006] However, conventionally used polymeric materials have good functional advantages when used e.g. as an acquisition and distribution layer, such as quick inlet and low rewet.

[0007] An object of the present disclosure is therefore to offer an absorbent hygienic article having a minimum of non-renewable materials, or even none, without losing functionality.

[0008] SUMMARY

[0009] The above objects may be achieved with an absorbent hygienic article in accordance with claim 1 and / or a method according to claim 19. Further embodiments are set out in the dependent claims, in the following description and in the drawings.

[0010] Thus, according to a first aspect of the present invention, there is provided an absorbent hygienic article for absorbing body fluids. The absorbent hygienic article comprises a topsheet, an acquisition distribution layer, an absorbent core and a backing layer, wherein the acquisition distribution layer is arranged between the topsheet and the absorbent core. The topsheet is a nonwoven material comprising cellulose-based fibres. The acquisition distribution layer is a nonwoven material comprising continuous filaments made of regenerated cellulose, which continuous filaments are multibonded by a combination of merged filaments, hydrogen bonding and physical intermingling of the filaments.

[0011] Accordingly, the topsheet and the acquisition distribution layer of the absorbent hygienic article according to the invention are to a major extent, or even substantially completely or completely, made of renewable materials. Yet, the absorbent hygienic article has good functional properties, such as quick inlet and low rewet. Hence, an absorbent hygienic article may be provided which has a minimum of non-renewable materials without losing functionality.

[0012] As may be concluded from the description herein of possible materials for the different layers of the absorbent hygienic article according to the invention, it is possible to provide an absorbent hygienic article, which to a major extent, or even substantially completely or completely, is made of renewable materials.

[0013] According to the invention, the topsheet is a nonwoven material comprising cellulose- based fibres. Hence, the topsheet may be constituted by a nonwoven material comprising a mixture of cellulose fibres with one or more of regenerated cellulose fibres, natural cellulose fibres and cellulose pulp fibres.

[0014] The term “cellulose-based fibres” as used herein comprises man-made and / or natural cellulose-based fibres. Examples of man-made cellulose-based fibres, also called regenerated cellulose-based fibres, are lyocell or viscose. Examples of natural cellulose-based fibres are seed hair fibres, e.g. cotton, kapok, and milkweed; leaf fibres, e.g. sisal, abaca, pineapple, and New Zealand hemp; or bast fibres e g flax, hemp, jute and kenaf.

[0015] The fibres may be cut to staple fibres. The cutting of the fibre bundle to staple fibres is normally done to result in a single cut length, which may be altered by varying the distances between the knives of the cutting wheel. Thereby the fibre length may be set depending on the planned use of the staple fibres.

[0016] The term “cellulose pulp fibres” as used herein comprises pulp fibres from chemical pulp, e.g. kraft, sulphate or sulphite, mechanical pulp, thermo-mechanical pulp, chemo-mechanical pulp and / or chemo-thermo-mechanical pulp, abbreviated as CTMP. Pulps derived from both deciduous (hardwood) and coniferous (softwood) may be used. Fibres may also come from non-wood plants, e.g. cereal straws, bamboo, jute or sisal. The fibres or a portion of the fibres may be recycled fibres, which may belong to any or all of the above categories.

[0017] The absorbent core may be symmetrical or asymmetrical in shape. It may for example be wider towards the front of the absorbent hygienic article than towards the rear of the absorbent hygienic article. The acquisition distribution layer may be narrower than the absorbent core, have the same shape as the absorbent core or be wider than the absorbent core, i.e. partly or fully extend beyond the periphery of the edge of the absorbent core. The acquisition distribution layer may also be shorter or longer than the length of the absorbent core in a longitudinal direction, i.e. it may or may not extend beyond the periphery of the absorbent core.

[0018] The topsheet may comprise cellulose-based staple fibres. The term “cellulose-based staple fibres” as used herein comprises both fibres, which have been cut from fibre bundles to a length being within a desired length range, and fibres having a natural length being within the desired length range, e.g. some of the natural cellulose-based fibres mentioned above, also called staple-length fibres. The desired length may e.g. be in the range of 2-25 mm, such as within the range of 2-20 mm, 5-15 mm or 6-12 mm.

[0019] The topsheet may be like the topsheet disclosed in WO 2021 / 126035 A1 , i.e. constituted by a cellulosic fibrous web, also referred to herein as a cellulose-based fibrous web, the fibres in the cellulosic fibrous web being constituted by a mixture of cellulose fibres comprising regenerated cellulose fibres and / or natural cellulose staple fibres and cellulose pulp fibres, the cellulosic fibrous web being a foam-formed, hydroentangled fibrous web. Alternatively, an absorbent layer in the absorbent core may be as disclosed in WO 2021 / 126035 A1 , i.e. constituted by a cellulosic fibrous web, the fibres in the cellulosic fibrous web being constituted by a mixture of cellulose fibres comprising regenerated cellulose fibres and / or natural cellulose staple fibres and cellulose pulp fibres, the absorbent fibrous web being a foam-formed, hydroentangled fibrous web. A further alternative is that both the topsheet and an absorbent layer in the absorbent core are as disclosed in WO 2021 / 126035 A1 , i.e. being formed by a respective cellulosic fibrous web, the fibres in the cellulosic fibrous web being constituted by a mixture of cellulose fibres comprising regenerated cellulose fibres and / or natural cellulose staple fibres and cellulose pulp fibres, the absorbent fibrous web being a foam-formed, hydroentangled fibrous web. The acquisition distribution layer of the absorbent hygienic article according to the invention is a nonwoven material comprising continuous filaments made of regenerated cellulose, which continuous filaments are multibonded by a combination of merged filaments, hydrogen bonding and physical intermingling of the filaments. Examples of such continuous filaments made of regenerated cellulose, also called man-made cellulose, are lyocell and viscose.

[0020] Multibonded refers to that bonding of the nonwoven material is obtained by more than one bonding method. In the acquisition distribution layer of the absorbent product of the invention, at least three different bonding methods contribute to the strength of the nonwoven material: merging, hydrogen bonding and physical intermingling.

[0021] Bonding by merging is obtained when filaments come into contact with each other before they are completely coagulated, i.e. solidified. Thereby, molecules from one filament mix irreversibly with molecules from a neighbouring filament. This kind of bonding may e.g. occur during manufacturing of lyocell filaments, e.g. in a meltblown or spunbond type process such as a lyocell process.

[0022] The lyocell process is a wet-spinning process, in which cellulose is dissolved in a solvent generating a viscous spinning solution, often referred to as a spin dope, which is extruded through at least one spinneret to form filaments. As long as there is still solvent left in the filaments, they will have sticky surface. If the filaments then come into contact with neighbouring filaments, they will stick to each other. Thereby, molecules from one filament mix irreversibly with molecules from a neighbouring filament. Hence, the filaments will be irreversibly locked to each other in the contact points after the solvent has been completely removed. The solvent may e.g. be washed out with water, which is a non-solvent for cellulose.

[0023] Hydrogen bonding is a chemical bonding occurring between the cellulose molecules.

[0024] Physical intermingling is a physical process in which filaments are mixed with neighbouring filaments. Typically, this happens as the filaments contact a forming belt. The filaments are traveling at a faster rate of speed than the forming belt. Hence, as the filaments contact the forming belt, they will buckle and sway side to side, and back and forth, just above the forming belt. During this buckling and swaying, the filaments will intermingle with neighbouring filaments.

[0025] Examples of how to perform multibonding are disclosed in WO 2018 / 184049 A1 , to which reference is made. Thereby, WO 2018 / 184049 A1 describes how to perform bonding by merging and physical intermingling.

[0026] The topsheet and the backing layer may be joined to each other in a peripheral join to enclose the absorbent core and the acquisition distribution layer, or the topsheet and the backing layer may be made of a single sheet of liquid permeable cover material which is wrapped around the absorbent core and the acquisition distribution layer. Furthermore, the topsheet and the backing layer may be indirectly joined, e.g. by being directly joined to the absorbent core, the acquisition distribution layer or another component arranged between the topsheet and the backing layer. Indirect joining of the topsheet and the backing layer may e.g. be employed if all of the topsheet, the backing layer, the acquisition distribution layer and the absorbent core are made from roll materials.

[0027] The topsheet and backing layer generally have a similar extension in the plane of the article, while the absorbent core and the acquisition distribution layer has an extension which is somewhat smaller. The absorbent core is at least located in the central region of the absorbent article and may also extend somewhat into the front and rear regions of the hygienic article. The topsheet and backing layer may be joined to one another by any means common in the art, e.g. ultrasonic welding, thermal welding or gluing.

[0028] One or more of the layers of the absorbent article may be glued or laminated to each other over a part of the surface, over a major part of the surface, over substantially the whole surface or over the whole surface. For example, the topsheet may be laminated to the acquisition distribution layer, which in turn may be glued to the absorbent core. This may improve the contact between the layers, such that fluid can be transported to the absorbent core in an efficient way. This can be achieved by for example spray or slot adhesive.

[0029] Generally, the backing layer is liquid impermeable or at least resistant to liquid penetration. The backing layer may be a breathable backing layer, as known in the art. It may further be preferred that the backing layer is derived from renewable raw materials. The absorbent core in the absorbent hygienic articles as disclosed herein may comprise superabsorbent material. Examples of superabsorbent materials suitable for use in the absorbent hygienic articles as disclosed herein are gelatine; alginates; cellulose based polymers such as methyl cellulose, hydroxymethyl cellulose, carboxymethylcellulose, cellulose acetate phthalate, and the like; starch based polymers such as carboxymethyl starch; natural gums, such as gum arabic, locust bean gum, carrageenan gum, and xanthan gum; pectins; polymers formed from acid-group containing monomers, such as poly-(acrylates), including poly(acrylic acid), poly(methacrylic acid), and the like) poly(ethers), poly-(acrylamides), poly(vinyl alcohol), maleic anhydride copolymers, poly(vinyl sulfonates), hydrolysed acrylonitrile grafted starch, acrylic acid grafted starch, poly(N-vinyl pyrrolidone), poly(2-hydroxyethylacrylate), poly(2-hydroxyethylmethacrylate), poly(sodium acrylate-co-acrylic acid), poly(vinylsulfonic acid); poly-(ethyleneoxide), block co-polymers of ethylene oxide with polyamides, polyesters, and polyurethanes, and salt forms, mixtures and copolymers of the above.

[0030] The absorbent core may to a major extent, or even substantially completely or completely, be made of renewable materials. It may be preferred that the superabsorbent materials used in the absorbent articles as disclosed herein are superabsorbents made from renewable raw materials such as cellulose-based superabsorbent materials or starch-based superabsorbent materials.

[0031] Additives such as softeners, dry-strength agents or wet-strength agents may be added in order to facilitate manufacturing of the topsheet, the acquisition distribution layer and / or the backing layer, or to adjust the properties thereof. However, the materials of the topsheet, the acquisition distribution layer and / or the backing layer may be so strong by themselves, that there is no need for a dry strength agent and / or a wet strength agent to improve strength.

[0032] The nonwoven material of the acquisition distribution layer may be hydroentangled, which may be seen as an alternative or a complement to the above-mentioned physical intermingling. Thereby the nonwoven material of the acquisition distribution layer is typically hydroentangled as a separate material web, i.e. not together with another web layer of the absorbent article. The hydroentangling process typically provides a lot of intermingling between the filaments. Hydroentangling may be used to customize properties such as thickness, drape, softness, strength and aesthetic appearance. Purely as an example, hydroentangling may be used to provide the nonwoven material with deliberately made apertures.

[0033] In a preferred embodiment, the continuous filaments of the acquisition distribution layer are viscose fibres and / or lyocell fibres. These fibres are made of renewable materials.

[0034] At least 80%, preferably at least 90%, more preferably at least 95% by weight of the nonwoven web material of the acquisition distribution layer may be constituted by the continuous filaments made of regenerated cellulose, most preferably the nonwoven web material of the acquisition distribution layer may consist of the continuous filaments made of regenerated cellulose. It is thereby possible to provide an acquisition distribution layer, which to a major extent, or even substantially completely or completely, is made of renewable materials.

[0035] The acquisition distribution layer may have a basis weight of from 20 gsm to 120 gsm, preferably from 30 gsm to 100 gsm, more preferably from 40 gsm to 80 gsm. Basis weight in these ranges have been found useful for an acquisition distribution layer being arranged between the topsheet and the absorbent core, as is the case for this invention.

[0036] The acquisition distribution layer may have a calculated density at a pressure of 0.5 kPa in the range of from 60 to 100 kg / m3, preferably in the range of from 70 to 90 kg / m3. Such materials have a fluffy structure, which has been found to be beneficial for the acquisition distribution layer, e.g. by contributing to the overall breathability of the absorbent hygienic article and to the wearer comfort.

[0037] The acquisition distribution layer may have a calculated density at a pressure of 2.0 kPa in the range of from 80 to 120 kg / m3, preferably in the range of from 85 to 105 kg / m3.

[0038] Such materials have a fluffy structure also when subjected to pressure, which has been found to be beneficial for the acquisition distribution layer. Hence, the acquisition distribution layer will remain fluffy also when the absorbent hygienic article is worn by a user and thereby subjected to different load situations during the use.

[0039] The acquisition distribution layer may have an air permeability above 3000 mm / s, preferably above 4000 mm / s, more preferably above 5000 mm / s, most preferably above 6000 mm / s, with air permeability being measured according to the standard method NWSP 070.1. RO (20), with test area 20 cm2and pressure 200 Pa. An upper limit may be 10000 mm / s or 12000 mm / s. Such materials have a fluffy structure, which has been found to be beneficial for the acquisition distribution layer e.g. by contributing to the overall breathability of the absorbent hygienic article and to the wearer comfort.

[0040] The cellulose-based fibres of the topsheet may be wood based and / or plant based. These fibres are examples of renewable materials.

[0041] At least 80%, preferably at least 90%, more preferably at least 95% by weight of the nonwoven web material of the topsheet may be constituted by the cellulose-based fibres, most preferably the nonwoven web material of the topsheet may consist of cellulose- based fibres. It is thereby possible to provide a topsheet which to a major extent, or even substantially completely or completely, is made of renewable materials.

[0042] The topsheet may have a basis weight of from 15 gsm to 40 gsm, preferably, more preferably. Basis weight in these ranges have been found useful for a topsheet of the absorbent hygienic article of this invention.

[0043] The absorbent hygienic article may have an inlet time of 3.4 seconds or less, preferably 3.1 seconds or less and more preferably 2.8 seconds or less for a first liquid insult, as measured according to the method disclosed herein, described in the section TEST METHODS below.

[0044] The absorbent hygienic article may have an inlet time of 7.0 seconds or less, preferably 6.5 seconds or less and more preferably 6.0 seconds or less and most preferably 5.5 seconds or less for a second liquid insult, as measured according to the method disclosed herein, described in the section TEST METHODS below.

[0045] The absorbent hygienic article may have an inlet time of 10.0 seconds or less, preferably 9.0 seconds or less and more preferably 8.0 seconds or less and most preferably 7.5 seconds or less for a third liquid insult, as measured according to the method disclosed herein, described in the section TEST METHODS below. Such inlet times after the first, second and third insults are perceived as positive by the user of the absorbent hygienic article, since these values indicate that the fluid disappears rapidly from the surface.

[0046] The absorbent hygienic article may have a rewet of 1.6 gram or less, such as a rewet of 1.5 gram or less as measured according to the method disclosed herein, described in the section TEST METHODS below. Such low rewet amounts are perceived as positive by the user of the absorbent hygienic article, since the experienced wetness of the absorbent hygienic article thus is low.

[0047] In an absorbent hygienic article as disclosed herein, 8% or less, preferably 6% or less, more preferably 4% or less, most preferably 2% or less of the artificial menstrual fluid used when testing rewet may be located in the acquisition distribution layer after rewet as measured according to the method disclosed herein.

[0048] At least 90%, preferably at least 92%, more preferably at least 94%, most preferably at least 96% of the artificial menstrual fluid used when testing rewet may be located in the absorbent core after rewet as measured according to the method disclosed herein.

[0049] Typically, the rest of the artificial menstrual fluid used when testing rewet is located in the topsheet, i.e. other than the artificial menstrual fluid located in the acquisition distribution layer and in the absorbent core is located in the topsheet, if assuming that there are no additional layers in the absorbent hygienic article.

[0050] In general, it is beneficial that as much of the artificial menstrual fluid as possible enters into and is captured by the absorbent core, since this lowers the risk of a user perceiving the absorbent hygienic article as wet. Furthermore, an acquisition distribution layer which retains only a small amount of liquid may act as a distance between a user’s skin and the majority of the liquid which is absorbed in the absorbent core. Hence, is desirable that the majority of the liquid, such as at least 90%, preferably at least 92%, more preferably at least 94%, most preferably at least 96%, which is absorbed by the absorbent hygienic articles as disclosed herein is absorbed and retained in the absorbent core.

[0051] The absorbent hygienic article according to the invention may for example be a sanitary napkin, a diaper or an incontinence protector. According to a second aspect of the present invention, there is provided a method of manufacturing an absorbent hygienic article as described herein. The method comprises

[0052] - providing a web of the topsheet material,

[0053] - providing a web of the acquisition distribution layer material,

[0054] - providing the absorbent core,

[0055] - providing a web of the backing layer material,

[0056] - joining the webs directly or indirectly such that the acquisition distribution layer is arranged between the topsheet and the absorbent core.

[0057] As mentioned above, the topsheet and the backing layer may be joined to each other in a peripheral join to enclose the absorbent core and the acquisition distribution layer, or the topsheet and the backing layer may be made of a single sheet of liquid permeable cover material which is wrapped around the absorbent core and the acquisition distribution layer. Furthermore, the topsheet and the backing layer may be indirectly joined, e.g. by being directly joined to the absorbent core, the acquisition distribution layer or another component arranged between the topsheet and the backing layer. Indirect joining of the topsheet and the backing layer may e.g. be employed if all of the topsheet, the backing layer, the acquisition distribution layer and the absorbent core are made from roll materials.

[0058] TEST METHODS

[0059] Absorbent hygienic articles or web samples of the layers of the absorbent hygienic articles disclosed herein can be subjected to testing according to the methods described herein.

[0060] Before testing, single absorbent hygienic articles or single layer web samples should rest flat and exposed for 24 hours in a stable laboratory environment set to 23°C and 50% relative humidity. All subsequent testing should then be made in this same environment.

[0061] Web thickness is measured under a pressure of 0.5 kPa. A suitable thickness gauge should have an accuracy of at least 0.01 mm. Pressure is exerted from a square foot measuring 50 x 50 mm. The foot is gently lowered onto the sample, and a thickness value is read after 5 seconds. A mean value is reported from measurements of ten representative samples

[0062] An additional thickness measurement was made in the same way but instead using a pressure of 2.0 kPa.

[0063] Density was calculated by dividing the known basis weight by the measured mean thickness and is reported in the unit kg / m3.

[0064] Determining Air Permeability

[0065] Air permeability is determined according to the standard method NWSP 070.1. RO (20).

[0066] Determining Inlet Rate, Rewet and Liguid Distribution

[0067] An artificial menstrual fluid, herein abbreviated as AMF, according to the French standard AFNOR Q34-018, is used when testing inlet rate, rewet and liguid distribution.

[0068] For the inlet rate and rewet determinations, the sample should rest flat on a laboratory bench. Folded absorbent hygienic articles are unfolded, and carefully stretched flat. A smooth, liguid impermeable polyethylene film should be placed underneath to prevent leakage.

[0069] The centre point of the sample is identified, i.e. the point where the longitudinal centreline crosses the transverse centreline. AMF is introduced via a tube (internal diameter about 2 mm) connected to an automatic dispenser. The orifice of the tube is positioned perpendicular to the centre point, with about 5 mm distance to the sample surface.

[0070] The sample is subjected to three 3.0 ml liguid insults of AMF (i.e. 9.0 ml in total), introduced at a rate of 150 ml / min. When a liguid insult has been absorbed (i.e. when there is no more free fluid on the sample surface), a stopwatch is started, and the next liguid insult is introduced after 15 minutes.

[0071] Rewet is measured 15 minutes after the third liguid insult, i.e. the last liguid insult of the test, has been absorbed. A stack of five pre-weighed filter papers (90 x 120 mm, 420 g / m2per sheet, Quality 167 from Munktell Ahlstrom or eguivalent filter papers) is centred on top of the sample. A 5.5 kg weight with bottom dimension 90 x 120 mm (exerting a pressure of 5 kPa) is gently lowered on top of the stack. After 15 seconds the weight is removed, the filter papers are weighed, and AMF rewet is determined. Mean values are reported from measurements of three representative samples.

[0072] In addition, the liquid distribution within the absorbent hygienic article was also evaluated. Materials of the different layers were weighed separately before adding the AMF liquid. After the rewet measurement, each layer was weighed separately again to obtain a weight in grams for the AMF liquid. Thereafter a percentage is calculated, for which the amount of AMF liquid in grams for each layer was divided with the total amount in grams of AMF liquid left in the complete absorbent hygienic article.

[0073] BRIEF DESCRIPTION OF THE DRAWINGS

[0074] The absorbent hygienic article as disclosed herein will be further explained hereinafter by means of non-limiting examples and with reference to the appended drawings wherein:

[0075] Fig. 1 shows a sanitary napkin according to the invention.

[0076] Fig. 2 shows a cross-section taken along the line ll-ll through the sanitary napkin of Fig. 1. Fig. 3 shows a comparison for inlet measurements.

[0077] Fig. 4 shows a comparison for rewet measurements.

[0078] Fig 5A-B shows environmental scanning electron microscope (ESEM) images.

[0079] DETAILED DESCRIPTION

[0080] It is to be understood that the drawings are schematic and that individual components or features, such as layers of material are not necessarily drawn to scale. The sanitary napkin shown in the figures is provided as an example only and should not be considered limiting to the invention as disclosed herein. In particular, it is to be understood that shape and dimensions are non-essential features of the invention and may be varied within the scope of the claims.

[0081] In the following, the claimed absorbent hygienic article is described with reference to a sanitary napkin, see Figures 1 and 2. As set out herein, the claimed invention is applicable to any other type of absorbent hygienic article comprising a topsheet, a backing layer, an acquisition distribution layer and an absorbent core with the acquisition distribution layer arranged between the topsheet and the absorbent core. The absorbent hygienic articles as disclosed herein are intended for being at least partly placed in the crotch portion of a user for absorbing blood, vaginal discharges, urine, faeces, etc. The absorbent hygienic articles of the invention include sanitary napkins, diapers for children and adults, incontinence protectors, etc.

[0082] Figure 1 is a schematic view of a sanitary napkin 10 according to the invention. Figure 2 shows a cross-section trough the sanitary napkin of Fig. 1. When going from the top wearer-facing side to the bottom garment-facing side of the sanitary napkin 10, it comprises a topsheet 12, an acquisition distribution layer 14, an absorbent core 16 and a backing layer 18.

[0083] The topsheet 12 and the backing layer 18 are joined to each other in a join 20 extending along the peripheral edge of the sanitary napkin 10. Such joins may be made e.g., by thermobonding, needling or by means of adhesive. Typically, the materials of the layers are supplied as roll materials from which the individual layers are cut out.

[0084] The topsheet 12 is a nonwoven material comprising cellulose-based fibres. Hence, the topsheet 12 may be constituted by a mixture of cellulose fibres comprising one or more of regenerated cellulose fibres, natural cellulose staple fibres and cellulose pulp fibres.

[0085] The acquisition distribution layer 14 is a nonwoven material comprising continuous filaments made of regenerated cellulose, which continuous filaments are multibonded by a combination of merged filaments, hydrogen bonding and physical intermingling of the filaments.

[0086] The absorbent core 16 may be of any type commonly used in sanitary napkins. Thereby, the absorbent core 16 may to a major extent, or even substantially completely or completely, be made of renewable materials. It may be preferred that the superabsorbent materials used, if any, in the absorbent articles are superabsorbents made from renewable raw materials such as cellulose-based superabsorbent materials or starch-based superabsorbent materials.

[0087] The absorbent core may be symmetrical or asymmetrical in shape. It may for example be wider towards the front of the absorbent hygienic article than towards the rear of the absorbent hygienic article. The acquisition distribution layer may be narrower than the absorbent core, have the same shape as the absorbent core or be wider than the absorbent core, i.e. partly or fully extend beyond the periphery of the edge of the absorbent core. The acquisition distribution layer may also be shorter or longer than the core length in longitudinal direction, i.e. it may or may not extend beyond the periphery of the absorbent core.

[0088] The backing layer 18 is of the type commonly used in sanitary napkins. It is liquid impermeable or at least resistant to liquid penetration.

[0089] Three samples of sanitary napkins were tested in order to evaluate the absorbent article of the invention. They all have the same topsheet, absorbent core and backing layer, but the acquisition distribution layers, abbreviated ADL, were different for the three samples.

[0090] Sample 1 is a sanitary napkin made according to the invention:

[0091] Topsheet: Glatfelter 25 gsm, 100% viscose fibres

[0092] ADL1 : Lenzing 65 gsm, Composition: 100% lyocell fibres, substantially continuous Absorbent Core: Saba ultra visible 470

[0093] Backing layer: Plastic layer, resistant to liquid penetration and liquid impermeable Hence, ADL1 is made of renewable material.

[0094] The absorbent core used for making Samples 1-3 is the absorbent core used for the product Saba Ultra Invisible buenos dias Toallas Ultradelgadas con alas (Regular), which is an ultra-thin day towel with wings sold in Mexico. The absorbent core comprises fluff pulp fibres, i.e. cellulose fibres. The absorbent core is mat-formed. It is formed in-line during manufacturing and is built up by defibrillated cellulose fibres. It is also compressed during manufacturing to get the right properties / density. There are no superabsorbents in the absorbent core. The absorbent core has a thickness of 3.7 mm and a grammage of 469 gsm, giving it a density of 127 kg / m3.

[0095] Sample 2 has another acquisition distribution layer, ADL2, which is made of a renewable material according to prior art:

[0096] ADL2: Mogul 70 gsm, carded, spunlaced nonwoven Composition: 100% viscose fibres Sample 3 has another acquisition distribution layer, ADL3, which is known to have good functional properties, but which is made of an oil-based polymeric material: ADL3: Glatfelter 70gsm, airlaid,

[0097] Composition: 75% pulp fibre + binder fibre + binder (EVA)

[0098] The results of the measurements are set out in Table 1 , showing data for the three different acquisition distribution layers, and in Table 2, showing data for the three different samples. See also the diagrams in Figure 3, showing inlet data, and Figure 4 showing rewet data for the samples.

[0099] Table 1: Measurements ADL

[0100] As can be seen in Table 1, ADL1 is has the highest thickness both at 0.5 kPa and 2.0 kPa. It is further seen that ADL2, having a renewable acquisition distribution layer according to prior art, has the lowest thickness both at 0.5 kPa and 2.0 kPa, while ADL3 has values in between the other two ADLs.

[0101] This is also reflected in the calculated density values, for which it can be seen that ADL1 is has the lowest density both at 0.5 kPa and 2.0 kPa. It is further seen that ADL2, having a renewable acquisition distribution layer according to prior art, has the highest both at 0.5 kPa and 2.0 kPa, while ADL3 has values in between the other two ADLs.

[0102] A high thickness, and thus a low density value, indicates that ADL1 has a fluffy structure, which has been found to be beneficial, e.g. by contributing to the overall breathability of the absorbent hygienic article and to the wearer comfort. As indicated by the values at 2.0 kPa, ADL1 has a fluffy structure also when subjected to pressure, Hence, the acquisition distribution layer will remain fluffy also when the absorbent hygienic article is worn by a user and thereby subjected to different load situations during the use.

[0103] The air permeability values show that ADL1 is much more air permeable than ADL2 and ADL3. The higher air permeability value of ADL1 indicates a fluffy structure, which, as mentioned above, has been found to be beneficial, e.g. by contributing to the overall breathability of the absorbent hygienic article and to the wearer comfort.

[0104] Table 2: Measurements Sanitary Napkin

[0105] As can be seen in Table 2 and Figure 3, Sample 1 has the lowest inlet time for all three insults. It is further seen that Sample 2, having a renewable acquisition distribution layer according to prior art, has the highest inlet times, while Sample 3 has values in between the other two samples but closer to Sample 2. Low inlet times are perceived as positive by the user of the absorbent hygienic article, since the fluid disappears rapidly from the surface.

[0106] As can be seen in Table 2 and Figure 4, rewet is on a similar level for Sample 1 and Sample 3, while Sample 2 has a higher rewet. Low rewet amounts are perceived as positive by the user of the absorbent hygienic article, since the experienced wetness of the absorbent hygienic article is low.

[0107] As regards liquid distribution, it can be seen that Sample 1 and Sample 3 have the same amount of artificial menstrual fluid left in the topsheet, both in grams and in per cent, while Sample 2 has more. Further, Sample 1 has the least amount of artificial menstrual fluid left in the acquisition distribution layer, while Sample 3 has more and Sample 2 much more. It thus follows that, Sample 1 has the highest amount of artificial menstrual fluid in the absorbent core, followed by Sample 3 and then by Sample 2. When comparing the values in grams, it should be considered that ADL2 and ADL3 are about 5 gsm heavier than ADL1

[0108] In general, it is beneficial that as much of the artificial menstrual fluid as possible enters into and is captured by the absorbent core, since this lowers the risk of a user perceiving the absorbent hygienic article as wet. Furthermore, an acquisition distribution layer which retains only a small amount of liquid may act as a distance between a user’s skin and the majority of the liquid which is absorbed in the absorbent core. It is desirable that the majority of the liquid, such as at least 90%, preferably at least 92%, more preferably at least 94%, most preferably at least 96%, which is absorbed by the absorbent hygienic articles as disclosed herein is absorbed and retained in the absorbent core.

[0109] When comparing the two samples with acquisition distribution layers made of renewable materials, it turns out that Sample 1 , being according to the invention, has much better functional properties than Sample 2, with an acquisition distribution layer according to prior art, as regards all the measured parameters.

[0110] When comparing Sample 1, being according to the invention, and Sample 3, with a conventional oil-based acquisition distribution layer, it turns out that Sample 1 has similar functional properties, as for rewet and liquid in topsheet, or better functional properties, as for all three inlets and liquid in core, than Sample 3.

[0111] The measurements thus show that, according to the invention, an absorbent hygienic article is provided, which has a minimum of non-renewable, e.g. oil-based, material, or even none, without losing functionality. Figure 5A shows an ESEM image at 100x of the Mogul carded, spunlaced 100% viscose 70gsm material used as ADL2 in Sample 2.

[0112] Figure 5B shows an ESEM image at 100x of the Lenzing 100% lyocell fibres, substantially continuous, 65gsm used as ADL1 in Sample 1.

Claims

CLAIMS1. An absorbent hygienic article (10) for absorbing body fluids, the absorbent hygienic article comprising a topsheet (12), an acquisition distribution layer (14), an absorbent core (16) and a backing layer (18), wherein the acquisition distribution layer (14) is arranged between the topsheet (12) and the absorbent core (16), the topsheet (12) being a nonwoven material comprising cellulose-based fibres, and the acquisition distribution layer (14) being a nonwoven material comprising continuous filaments made of regenerated cellulose, which continuous filaments are multibonded by a combination of merged filaments, hydrogen bonding and physical intermingling of the filaments.

2. An absorbent hygienic article (10) according to claim 1, wherein the nonwoven material of the acquisition distribution layer (14) is hydroentangled.

3. An absorbent hygienic article (10) according to claim 1 or 2, wherein the continuous filaments of the acquisition distribution layer (14) are viscose fibres and / or lyocell fibres.

4. An absorbent hygienic article (10) according to any one of the preceding claims, wherein at least 80%, preferably at least 90%, more preferably at least 95% by weight of the nonwoven web material of the acquisition distribution layer (14) is constituted by the continuous filaments made of regenerated cellulose, most preferably the nonwoven web material of the acquisition distribution layer (14) consists of the continuous filaments made of regenerated cellulose.

5. An absorbent hygienic article (10) according to any one of the preceding claims, wherein the acquisition distribution layer (14) has a basis weight of from 20 gsm to 120 gsm, preferably from 30 gsm to 100 gsm, more preferably from 40 gsm to 80 gsm.

6. An absorbent hygienic article (10) according to any one of the preceding claims, wherein the acquisition distribution layer (14) has a calculated density at a pressure of 0.5 kPa in the range of from 60 to 100 kg / m3, preferably in the range of from 70 to 90 kg / m3.

7. An absorbent hygienic article (10) according to any one of the preceding claims, wherein the acquisition distribution layer (14) has a calculated density at a pressure of 2.0 kPa in the range of from 80 to 120 kg / m3, preferably in the range of from 85 to 105 kg / m3.

8. An absorbent hygienic article (10) according to any one of the preceding claims, wherein the acquisition distribution layer (14) has an air permeability above 3000 mm / s, preferably above 4000 mm / s, more preferably above 5000 mm / s, most preferably above 6000 mm / s.

9. An absorbent hygienic article (10) according to any one of the preceding claims, wherein the cellulose-based fibres of the topsheet (12) are wood based and / or plant based.

10. An absorbent hygienic article (10) according to any one of the preceding claims, wherein at least 80%, preferably at least 90%, more preferably at least 95% by weight of the nonwoven web material of the topsheet (12) is constituted by the cellulose-based fibres, most preferably the nonwoven web material of the topsheet (12) consists of cellulose-based fibres.

11. An absorbent hygienic article (10) according to any one of the preceding claims, wherein the topsheet (12) has a basis weight of from 15 gsm to 40 gsm, preferably, more preferably.

12. An absorbent hygienic article (10) according to any one of the preceding claims, wherein the absorbent hygienic article has an inlet time of 3.4 seconds or less, preferably 3.1 seconds or less and more preferably 2.8 seconds or less for a first liquid insult, as measured according to the method disclosed herein.

13. An absorbent hygienic article (10) according to any one of the preceding claims, wherein the absorbent hygienic article has an inlet time of 7.0 seconds or less, preferably 6.5 seconds or less and more preferably 6.0 seconds or less and most preferably 5.5 seconds or less for a second liquid insult, as measured according to the method disclosed herein.

14. An absorbent hygienic article (10) according to any one of the preceding claims, wherein the absorbent hygienic article has an inlet time of 10.0 seconds or less, preferably 9.0 seconds or less and more preferably 8.0 seconds or less and most preferably 7.5 seconds or less for a third liquid insult, as measured according to the method disclosed herein.

15. An absorbent hygienic article (10) according to any one of the preceding claims, wherein the absorbent hygienic article has a rewet of 1.6 gram or less, such as a rewet of 1.5 gram or less as measured according to the method disclosed herein.

16. An absorbent hygienic article (10) according to any one of the preceding claims, wherein 8% or less, preferably 6% or less, more preferably 4% or less, most preferably 2% or less of the artificial menstrual fluid is located in the acquisition distribution layer (14) after rewet as measured according to the method disclosed herein.

17. An absorbent hygienic article (10) according to any one of the preceding claims, wherein at least 90%, preferably at least 92%, more preferably at least 94%, most preferably at least 96% of the artificial menstrual fluid is located in the absorbent core (16) after rewet as measured according to the method disclosed herein.

18. An absorbent hygienic article (10) according to any one of the preceding claims, wherein the absorbent hygienic article (10) is a sanitary napkin, a diaper or an incontinence protector.

19. A method of manufacturing an absorbent hygienic article (10) according to any one of the preceding claims, the method comprising- providing a web of the topsheet (12) material,- providing a web of the acquisition distribution layer (14) material,- providing the absorbent core (16),- providing a web of the backing layer (18) material,- joining the webs directly or indirectly such that the acquisition distribution layer (14) is arranged between the topsheet (12) and the absorbent core (16).

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