Absorbent article with open-ported toplet comprising

Abstract

The present invention relates to an absorbent article having a wearer-facing surface and a garment-facing surface, the absorbent article comprising: a topsheet, a backsheet, and a layer of absorbent material disposed between the topsheet and the backsheet wherein the topsheet comprises a first layer comprising cellulose-based fibers, the first layer comprises a first surface, an opposite second surface and a plurality of holes with side walls, and the first surface of the first layer forms at least one part of the surface facing the wearer; wherein the first surface of the first layer comprises at least one non-hole region having a first non-hole region contact angle measured by a contact angle test; and wherein each hole of the majority of holes has a sidewall having a hole contact angle measured by a contact angle test, the hole contact angle being higher than the first non-hole area contact angle.

Description

Technical Field

[0001] The present invention relates to an absorbent article comprising an apertured topsheet comprising natural fibers. Background Art

[0002] Absorbent articles have been used as personal hygiene products, such as sanitary napkins, disposable diapers for infants, training pants for young children, incontinence underwear for adults, etc. Such absorbent articles are designed to absorb and contain body exudates, especially large amounts of urine, loose stools, and / or menstrual fluids (collectively referred to as "fluids"). These absorbent articles may include several layers providing different functions, such as a top sheet, a back sheet, and an absorbent core disposed therebetween, as well as other layers (such as a collection layer, a distribution layer, etc.) as needed.

[0003] One of the design criteria for topsheets in absorbent articles is to reduce the amount of time that fluid spends on the topsheet before being absorbed by the absorbent article. If fluid remains on the surface of the topsheet for too long, the wearer may not feel dry and discomfort may increase. Another desired quality of a topsheet is to prevent backflow of fluid through the topsheet and provide a sense of dryness.

[0004] In order to solve the problem of the wearer's skin feeling wet due to long-term fluid retention on the top sheet, an apertured top sheet has been used to allow the fluid to penetrate into the absorbent article faster. Although an apertured top sheet generally reduces the residence time of the fluid on the top sheet, it can cause fluid backflow through the top sheet.

[0005] At the same time, the topsheet captures and retains some fluid in small capillaries that may exist between the fibers, which may be visually perceived by the user of the product as an undesirable stain.Another desirable characteristic of absorbent articles is to present a clean user contacting surface with fewer stains.

[0006] Recently, there has been a growing interest in supplementing or replacing the synthetic components of nonwoven fabrics with natural or cellulose-based fibers to meet consumer demand for materials that are natural, mild to the skin, and more environmentally friendly. For example, natural fibers, especially natural cellulose-based fibers (such as cotton), can be blended with synthetic fibers, or can replace synthetic fibers.

[0007] Natural fibers tend to be highly hydrophilic after destruction and washing. Therefore, in absorbent articles with topsheets containing natural fibers, body fluids remain on and in the topsheet for a long time, which causes a sense of dampness and skin discomfort in the user. As an effort to solve the problem of skin feeling dampness during use, topsheets containing natural fibers can be treated with treatment agents and / or have multiple holes. Although the perforated topsheet has generally reduced the fluid spread on the topsheet by allowing body fluids to penetrate more quickly, the perforated hydrophobic topsheet may still have a relatively high slippage, for example, due to relatively small holes, liquid only slowly penetrates the topsheet through these relatively small holes or even does not penetrate the topsheet through these relatively small holes at all.

[0008] There remains a need for absorbent articles having a topsheet comprising cellulose-based fibers that can reduce fluid backflow through the topsheet without compromising fluid acquisition rate.

[0009] There also remains a continuing need for absorbent articles having topsheets comprising cellulose-based fibers that can provide improved surface cleaning of body fluids. Summary of the invention

[0010] The present invention relates to an absorbent article having a wearer-facing surface and a garment-facing surface, the absorbent article comprising: a top sheet, a back sheet and an absorbent material layer arranged between the top sheet and the back sheet, wherein the top sheet comprises a first layer comprising cellulose-based fibers, the first layer comprising a first surface, an opposite second surface and a plurality of holes having side walls, wherein the first surface of the first layer forms at least a portion of the wearer-facing surface; wherein the first surface of the first layer comprises at least one non-porous area, the at least one non-porous area having a first non-porous area contact angle measured by a contact angle test; and wherein each of the holes in most of the holes has a side wall, the side wall having a hole contact angle measured by a contact angle test, the hole contact angle being higher than the first non-porous area contact angle.

[0011] The present invention also relates to a method for producing an open-cell nonwoven fabric, the method comprising the steps of: a) providing a first layer comprising cellulose-based fibers, a first surface and an opposing second surface; b) providing an open-cell apparatus comprising a first forming member and a second forming member engaged with the first forming member, wherein the first forming member comprises a plurality of pins on a surface thereof and the second forming member comprises a plurality of grooves on a surface thereof; c) wetting the pins on the first forming member with a treating agent having an HLB value of not greater than about 13; and d) moving the first layer between the first forming member and the second forming member such that pores are formed in the first layer when the pins on the first forming member engage with the grooves on the second forming member, wherein the first surface of the first layer comprises at least one non-porous area having a first non-porous area contact angle measured by a contact angle test, and wherein each of the pores in a majority of the pores has a sidewall having a pore contact angle measured by a contact angle test that is higher than the first non-porous area contact angle.

[0012] For ease of discussion, absorbent articles will be discussed with reference to the reference numerals mentioned in these drawings. However, unless otherwise expressly indicated, the drawings and detailed description should not be considered to limit the scope of the claims, and the invention disclosed herein is also applicable to various absorbent article forms. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In the drawings, like reference numbers or other designations refer to like parts throughout the views.

[0014] Figure 1 is a perspective view of an exemplary absorbent article.

[0015] Figure 2 is a schematic plan view of an exemplary absorbent article.

[0016] Figure 3 For along Figure 2 3-3 is a side cross-sectional view of the absorbent article.

[0017] Figure 4A is a schematic diagram of a top sheet with a flat first layer according to the present invention.

[0018] Figure 4B is a schematic diagram of a top sheet with a flat first layer according to the present invention.

[0019] Figure 5 is a schematic diagram of a top sheet with a three-dimensional first layer according to the present invention.

[0020] Figure 6 Schematic diagram of a top sheet having a first layer and a second layer according to the present invention.

[0021] Fig. 7Ais a schematic diagram of a top sheet according to the present invention having a three-dimensional first layer and a flat second layer.

[0022] Figure 7B is a schematic diagram of a three-dimensional top sheet according to the present invention having a first layer and a flat second layer.

[0023] Figure 8 is a schematic diagram of an apparatus for applying a treatment composition to a nonwoven substrate.

[0024] Fig.9A A perspective view of the strikethrough plate used for acquisition time measurements.

[0025] Fig. 9B for Fig.9A A plan view of a vapor permeable panel.

[0026] Fig. 9C for Fig. 9B A plan view of the cross section of the breathable plate in the 9C-9C direction.

[0027] Fig.9D for Fig. 9B A plan view of the parts pf of the breathable plate.

[0028] Fig.9E for Fig. 9B A plan view of the cross section of the breathable plate in the 9E-9E direction.

[0029] Fig.10 is a photomicrograph showing an exemplary liquid drop on a fiber used in the contact angle test method disclosed herein.

[0030] Fig.11 is a schematic plan view of a top sheet disclosed herein. DETAILED DESCRIPTION

[0031] Various non-limiting forms of the present disclosure will now be described to provide an overall understanding of the principles of the structure, function, manufacture and use of an absorbent article, which includes an open-cell top sheet comprising cellulose-based fibers, which has reduced back permeability and improved stain shielding. One or more examples of these non-limiting embodiments are shown in the accompanying drawings. It will be understood by those of ordinary skill in the art that the absorbent articles described herein and shown in the accompanying drawings are non-limiting example forms, and the scope of the various non-limiting forms of the present disclosure is fully defined by the claims. The characteristic structures shown or described in conjunction with one non-limiting form can be combined with the characteristic structures of other non-limiting forms. Such modifications and variations are intended to be included within the scope of the present disclosure.

[0032] "Absorbent article" refers to a wearable device that absorbs and contains liquids, and more specifically, refers to a device that is placed close to or adjacent to the wearer's body to absorb and contain various exudates discharged from the body. Absorbent articles may include diapers, training pants, adult incontinence underwear, feminine hygiene products (such as sanitary napkins, menstrual pants and sanitary pads), and wipes.

[0033] As used herein, the term "comprising" refers to various components, ingredients or steps that can be combined and applied in the process of implementing the present invention. Therefore, the term "comprising" is an open-ended term and includes the more restrictive terms "essentially consisting of..." and "consisting of..."

[0034] As used herein, the term "cellulose-based fibers" is intended to include natural cellulose fibers, such as pulp and cotton, and regenerated cellulose fibers, such as rayon (including viscose, lyocell, MODAL (a product of Lenzing AG, Lenzing, Austria) and cuprammonium rayon), unless otherwise specified.

[0035] As used herein, the terms "hydrophilic" and "hydrophobic" have their generally accepted meanings in the art with respect to the contact angle of water on a material surface. Thus, a material having a water contact angle greater than about 90° as measured by a contact angle test is considered hydrophobic, and a material having a water contact angle less than about 90° as measured by a contact angle test is considered hydrophilic.

[0036] As used herein, the term "natural fiber" refers to elongated materials produced by plants and animals, and includes animal-based fibers and plant-based fibers. Natural fibers can include fibers harvested without any post-harvest processing steps, as well as fibers with post-processing steps such as, for example, washing, scouring, and bleaching.

[0037] As used herein, the term "plant-based fibers" includes both harvested fibers and synthetic fibers containing bio-based content. Harvested plant-based fibers can include cellulosic materials such as wood pulp; seed hairs such as cotton; stem (or bast) fibers such as flax and hemp; leaf fibers such as sisal; and husk fibers such as coconut.

[0038] Absorbent products

[0039] Absorbent articles will now be discussed generally and further illustrated in the form of a sanitary napkin 100, as shown in FIG. Figure 1 Presented exemplarily. Figure 1 FIG. 1 is a plan view of an exemplary sanitary napkin 100 in a flat configuration with the garment-facing side turned over. Figure 1As shown, an absorbent article according to the present invention (e.g., a sanitary napkin 100) includes a top sheet 24 having a wearer-facing surface and a garment-facing surface ( Figure 1 2). The absorbent article further comprises a backsheet 26 having a garment-facing surface and a user-facing surface positioned opposite the garment-facing surface and at least partially joined to the topsheet 24. The absorbent article further comprises an absorbent core 28 positioned between the topsheet 24 and the backsheet 26. The absorbent article may further comprise an optional acquisition and / or distribution layer (or system) or a second topsheet 50 presented and / or a pair of wings or wings 23. The topsheet 24, the backsheet 26 and the absorbent core 28 may be assembled in various well-known configurations.

[0040] The backsheet 26 and topsheet 24 can be secured together in a variety of ways. The topsheet 24 and backsheet 26 can be joined to each other using adhesive heat bonding, pressure bonding, ultrasonic bonding, dynamic mechanical bonding, or crimp seals. Fluid-impermeable crimp seals prevent lateral migration of fluid through the edges of the product ("wicking"), inhibiting side soiling of the user's underwear.

[0041] When the absorbent article is Figure 1 When the sanitary napkin is shown, as is typical of sanitary napkins and the like, the sanitary napkin may have a panty adhesive disposed on the garment-facing side of the backsheet 26. The panty adhesive may be any adhesive known in the art for this purpose and may be covered by a release paper prior to use as is well known in the art. If side flaps or wings are present, the panty adhesive may be applied to the garment-facing side so as to contact and adhere to the underside of the user's panties.

[0042] The absorbent article will further be shown in the form of a baby diaper 20, such as Figure 2 Presented exemplarily. Figure 2 1 is a plan view of an exemplary diaper 20 in a flat configuration, wherein the adhesive ends are open and the garment-facing side is turned over. A closed article such as training pants presented to the user can also be flattened by cutting along its side waist. An absorbent article generally has a front edge 110, a rear edge 112, and lateral side edges 113, 114 extending longitudinally. The front edge 110 forms the edge of the front waist and the rear edge 112 forms the edge of the rear waist, which together form an opening for the wearer's waist when worn by the wearer. The lateral edges 113, 114 can each form a leg opening. The absorbent article 20 hypothetically includes a longitudinal centerline 80 that divides the article into a left side and a right side and a vertical transverse centerline 90 that is arranged at half of the article length measured on the longitudinal centerline 80, wherein the two centerlines intersect at a center point C. The adhesive rear end 42 is attached to a landing zone 44 such as at the front of the diaper.

[0043] The other layers of the absorbent article are better shown in Figure 3 In the figure, in addition to showing the liquid-permeable top sheet 24 and the back sheet 26 in cross section, an absorbent core 28 located between the top sheet 24 and the back sheet 26 is also shown.

[0044] An optional acquisition and / or distribution layer (or system) 50 is shown along with other typical diaper components. Figure 3 The acquisition and / or distribution layer may comprise one layer or more than one layer. The acquisition and / or distribution layer may not typically contain SAP, as this may slow down the acquisition and distribution of the fluid, but if a certain degree of fluid retention properties is desired, additional layers may also contain SAP.

[0045] The absorbent article may typically include a pair of partially upright barrier leg cuffs 34 having elastic elements 35 and elasticized gasketing cuffs 32 having elastic elements 33 that are substantially coplanar with the chassis. Typically, both types of cuffs are joined to the chassis of the absorbent article, typically via bonding to the topsheet and / or backsheet.

[0046] The absorbent article may include elasticized back ears 40 having taped ends 42 that may be attached to a landing zone 44 at the front of the article, and front ears 46 typically found in such taped diapers.

[0047] Topsheet comprising cellulose-based fibers

[0048] The topsheet is generally liquid permeable and is configured to receive fluid being discharged from the body and help guide the fluid toward the acquisition system / distribution layer (system) and / or toward the absorbent core. One of the important qualities of a topsheet is the ability to reduce the accumulation of fluid on the topsheet before the fluid can be absorbed by the absorbent article. Another desired quality of a topsheet is to reduce the rewet of the topsheet. It is also desirable that the topsheet presents a clean user contact surface with fewer stains.

[0049] The top sheet in the present invention is the portion of the absorbent article that contacts the wearer's skin during use of the article. As known to those of ordinary skill in the art, the top sheet may be joined to a backsheet, an absorbent core, and / or portions of any other layer. In addition, at least a portion or all of the top sheet may be liquid permeable, allowing liquid body exudates to easily penetrate its thickness.

[0050] The topsheet of the present invention comprises cellulose-based fibers and may also comprise synthetic fibers, such as thermoplastic fibers.

[0051] The top sheet in the present invention comprises a first layer comprising cellulose-based fibers. The top sheet may be formed of a single layer or two layers, or may be formed of more than two layers.

[0052] The synthetic fibers may be selected from polyester, polypropylene, polyethylene, polyether, polyamide, polyhydroxyalkanoate, polysaccharide, and combinations thereof. In addition, other synthetic fibers such as rayon, polyethylene and polypropylene fibers may also be used within the scope of the present disclosure.

[0053] Thermoplastic fibers can be single component fibers (i.e., a single synthetic material or mixture used to constitute the entire fiber), multicomponent fibers such as bicomponent fibers (i.e., fibers are divided into multiple regions that include two or more different synthetic materials or mixtures thereof), and combinations thereof.

[0054] The top sheet may also include semisynthetic fibers made from polymers, particularly hydroxyl polymers. Non-limiting examples of suitable hydroxyl polymers include polyvinyl alcohol, starch, starch derivatives, chitosan, chitosan derivatives, cellulose derivatives such as viscose, gum, arabinan, galactan, lyocell (Tencel ® ) and their combinations.

[0055] The cellulose-based fibers may be selected from the group consisting of wheat straw fibers, rice straw fibers, flax fibers, bamboo fibers, cotton fibers, jute fibers, hemp fibers, sisal fibers, bagasse fibers, yucca fibers, and combinations thereof.

[0056] The topsheet in the present invention may comprise a woven web or a nonwoven web.

[0057] Several examples of nonwoven materials suitable for use as a top sheet may include, but are not limited to: spunbond nonwoven materials; carded nonwovens; air-carded nonwoven materials; hydroentangled nonwoven materials, needle-punched nonwoven materials, and nonwoven materials having relatively specific properties to enable easy deformation.

[0058] Nonwoven webs can be formed by many methods, such as air-laid, wet-laid, melt-blown, spunbonded, needle-punched, and carded. The fibers in the nonwoven web can then be bonded via hydroentanglement, hydroknitting, calendering, through-air bonding, and resin bonding.

[0059] The topsheet may comprise a hydroentangled nonwoven fabric.

[0060] The top sheet may have a thickness of about 10 g / m 2 About 200g / m 2 , or about 20g / m 2 About 100g / m 2 , or about 25g / m 2 About 60g / m 2 , or about 30g / m 2 About 50g / m 2 The basis weight.

[0061] First floor

[0062] The first layer comprises cellulose-based fibers and may be a woven web or a nonwoven web.The first layer may also comprise thermoplastic fibers.

[0063] The list of thermoplastic fibers and cellulose-based fibers and the nonwoven web manufacturing method correspond to the list and method disclosed above for the topsheet.

[0064] Cotton fiber is a natural cellulose fiber, which has good liquid acquisition, good air permeability and good softness.Therefore, a topsheet having a first layer comprising cotton fibers improves the softness of the topsheet while improving the fluid handling properties of the topsheet.

[0065] The first layer comprises at least 15 wt%, or at least 30 wt%, or at least 50 wt%, or at least 60 wt%, or at least 75 wt%, or at least 95 wt% of cellulose-based fibers (such as cotton fibers and rayon fibers) based on the total weight of the first layer. The first layer may be made of 99 wt% to 100 wt% of cellulose-based fibers (such as cotton fibers and rayon fibers) based on the total weight of the first layer.

[0066] Since the first layer of the top sheet faces the skin of the wearer of the absorbent article during use of the article, having a high content of cellulose-based fibers in the first layer of the top sheet can give the wearer's skin a soft feel, as well as increase the amount of biodegradable material in contact with the wearer's skin and reduce the risk of allergies, irritation or rash on the wearer's skin.

[0067] The first layer includes a first surface, an opposite second surface, and a plurality of pores. The first surface of the first layer includes at least one non-porous region, the at least one non-porous region having no pores.

[0068] The non-porous regions may completely surround the pores. The non-porous regions may together form a substantially continuous grid throughout the first surface of the first layer, while the pores may be discrete elements dispersed in the continuous grid and surrounded by them.

[0069] The non-porous area can be a plurality of discrete areas defined by holes. Each of the plurality of discrete non-porous areas has a perimeter formed by a continuous line of holes, with adjacent holes spaced apart by an edge-to-edge distance of no more than 3 mm. In addition, each of the plurality of discrete non-porous areas has substantially no holes within the perimeter. At least some of the plurality of discrete non-porous areas are sufficiently large, i.e., have a perimeter of about 50 mm as measured according to the non-porous area size measurement. 2 or larger, or about 60mm 2 or larger area.

[0070] The non-hole area may be a landing area or a protrusion.

[0071] The non-porous region is hydrophilic and has a first non-porous region contact angle. The first non-porous region contact angle measured by the Contact Angle Test may be no greater than about 15°, or no greater than about 10°, or no greater than about 5°. The non-porous region may comprise hydrophilic fibers or fibers treated with a hydrophilic treatment agent.

[0072] Hydrophobic fibers can be rendered hydrophilic by treating them with a hydrophilic treating agent, such as a hydrophilic surfactant, for example by spraying the hydrophobic fibers with the hydrophilic treating agent, dipping the fibers into the treating agent, or including the hydrophilic treating agent as part of the polymer melt in producing the thermoplastic fibers. Upon melting and resolidification, the treating agent will tend to remain at the surface of the fibers.

[0073] The non-porous region of the first surface may be free of a treatment agent.The non-porous region of the first surface may include a hydrophilic treatment agent.

[0074] The first layer includes a plurality of holes. Each hole in most of the plurality of holes includes a sidewall having a hole contact angle measured by a contact angle test, and the hole contact angle is higher than the first non-porous area contact angle. The hole contact angle measured by the contact angle test can be equal to or higher than about 40 °, or equal to or higher than about 45 °, or equal to or higher than about 50 °. The hole contact angle can be at least 20 °, or at least 30 °, or at least 40 ° higher than the first non-porous area contact angle.

[0075] The sidewalls of each hole may be treated with a treating agent, such as a treating agent having an HLB value of no greater than about 13.

[0076] The HLB values ​​of commonly used treatment agents are easily obtained in the literature (e.g., the HLB index in McCutcheon's Emulsifiers and Detergents, MC Publishing Co., 2004). Another way to obtain the HLB value is to estimate it by calculation. The HLB system was originally invented by Griffin (J. Soc. Cosmetic Chem., 1, 311, 1949). Griffin defined the HLB value of a surfactant as the molar percentage of hydrophilic groups divided by 5, where all hydrophilic molecules (without non-polar groups) have an HLB value of 20. Other examples of how to calculate HLB values ​​are described in the following literature: Davies in Interfacial Phenomena, 2nd edition, Academic Press, London, 1963 and Lin in J. Phys. Chem. 76, 2019-2013, 1972.

[0077] The first layer may comprise a mixture of hydrophobic fibers and hydrophilic fibers. The amount of hydrophilic fibers may be higher than the amount of hydrophobic fibers. For example, the first layer may comprise a mixture of 5 to 40 wt % of hydrophobic fibers and 60 to 95 wt % of hydrophilic fibers, based on the total weight of the first layer. For example, the first layer may comprise a mixture of 5 to 40 wt % of hydrophobic synthetic fibers and 60 to 95 wt % of hydrophilic cellulose-based fibers, based on the total weight of the first layer.

[0078] The first layer may be a spunlace nonwoven layer. The spunlace layer may be composed of a carrier web and a web comprising cellulose-based fibers, wherein a portion of the web comprises cellulose-based fibers entering the carrier web. The carrier web may be a nonwoven web.

[0079] A fiber web comprising cellulose-based fibers may be formed on one side of a carrier fiber web. The cellulose-based fibers of the natural fiber web may enter the fiber network of the carrier fiber web and interweave with the fiber network. It is understood that the cellulose-based fibers may be interwoven with each other. The carrier fiber web may also be interwoven with a fiber web comprising cellulose-based fibers.

[0080] The carrier fiber web can be made of different types of synthetic fibers. The carrier fiber web can also be made of cellulose fibers.

[0081] The first layer can have various structures.

[0082] See also Figure 4A , the top sheet 24 comprises at least a first layer 1. The first layer 1 comprises a first surface 3 and a second surface 4.

[0083] The first layer 1 comprises a plurality of holes 5. To ensure the stability of the material, regardless of their specific shape and width, the minimum edge-to-edge distance between most of the holes is at least 0.5 mm, or at least 1.5 mm or 2.0 mm. This distance is measured on the first surface 3 of the first layer 1 of the top sheet.

[0084] The shape of the hole can vary. For example, the shape of the hole seen from the first surface of the first layer can be circular, elliptical, rectangular or polygonal. In one embodiment, the hole has a circular shape, an elliptical shape or a polygonal shape.

[0085] The three-dimensional shape of the hole may be a cylinder (eg, with a circular or oval base), a prism (eg, with a polygonal base), or a truncated cone or pyramid.

[0086] Each of the holes 5 has a side wall 6. The side wall 6 may extend outwardly away from a landing area 8 of the second surface of the first layer, such as Figure 4A When the topsheet described herein is incorporated into an absorbent article, the sidewalls of the apertures may be oriented toward the absorbent core of the absorbent article as they extend outwardly.

[0087] The sidewalls of the aperture may extend at least 0.1 mm beyond the second surface of the first layer, or at least 0.2 mm beyond the second surface of the first layer.The sidewalls of the aperture may form a funnel or a channel.

[0088] The side wall 6 may not extend outwards. Figure 4B shown.

[0089] The hole may be tapered and have a conical shape such that the diameter of the hole is larger at a portion of the hole adjacent to the first surface of the first layer than at a bottom edge of the hole.

[0090] Such a tapered configuration helps reduce the risk of rewet, i.e., body fluids flowing back from components below the topsheet, such as the absorbent core, and through the topsheet. With an apertured hydrophobic topsheet, rewet occurs primarily through the apertures. The tapered shape of the apertures can help reduce rewet because the diameter of the apertures toward the absorbent core is smaller than the diameter of the apertures in the first layer.

[0091] The plurality of holes may also vary in width.

[0092] A majority of the pores may contain the treating agent.

[0093] The treatment may be applied via pin coating as described in detail below or other application methods known in the art. The treatment may be applied to a majority of the holes via a hole forming process such as a pin hole process or via a printing process.

[0094] The holes of the first layer of the top sheet may have at least 2.5% open area, or at least 3% open area, or at least 3% open area. The holes of the first layer of the top sheet may have no more than about 10% or no more than 8% open area.

[0095] Each of the majority of the pores, or at least 70% of the pores, or at least 80% of the pores, or at least 90% of the pores has a sidewall having a pore contact angle as measured by a Contact Angle Test that is higher than the first non-pore area contact angle.

[0096] The size of the holes can be determined to achieve the desired fluid and / or air permeability and other properties desired by the wearer. If the holes are too small, fluid may not be able to pass through the holes due to misalignment of the fluid source with the location of the holes or due to, for example, loose stool having a diameter larger than the holes. If the holes are too large, the skin area that can be contaminated by "rewet" from the article increases.

[0097] When the majority of the pores include sidewalls having a pore contact angle higher than the contact angle of the first non-pore region, each of the plurality of pores may have a contact angle within 0.2 mm. 2 Up to 1.5mm 2 , 0.2mm 2 Up to 1.0mm2 , or 0.25mm 2 Up to 0.5mm 2 The plurality of holes may have a regular shape selected from the group consisting of: circle, oval, triangle, square, rectangle, parallelogram, trapezoid, polygon, hourglass, star, and any combination thereof.

[0098] The apertures in the topsheet of the present invention are less likely to trap or retain fluid through or between fibers because the sidewalls have an aperture contact angle as measured by the Contact Angle Test that is higher than the first non-aperture area contact angle, preferably higher than about 40°. Thus, the topsheet disclosed herein provides improved fluid handling properties, such as reduced back-wet onto the wearer-facing surface of the absorbent article and good stain shielding without compromising fluid acquisition rate.

[0099] according to Figure 5 , the first layer 1 may comprise a plurality of protrusions 9. The first layer 1 comprises a plurality of holes 5. The first layer 1 comprises a landing area 8 between most of the holes 5. The landing area may be substantially flat.

[0100] Most of the protrusions 9 may protrude outwardly from the landing area 8 of the first layer 1 of the top sheet 24 .

[0101] The first layer 1 has a first surface 3 and a second surface 4. Most of the protrusions 9 may be located on the first surface 3 of the first layer 1. Most of the protrusions 9 may extend outwardly from the first surface 3 of the first layer 1.

[0102] The plurality of protrusions 9 may be uniformly distributed on the first surface 3 of the first layer 1. The plurality of protrusions 9 may be uniformly distributed and form a shape or pattern on the first surface 3 of the first layer 1. Most of the protrusions 9 may be provided over the entire surface of the first layer 1, or may be provided only in a portion of the first layer 1.

[0103] Most of the protrusions 9 may be surrounded by a plurality of landing areas 8 and / or a plurality of holes 5 .

[0104] The plurality of land areas 8 , the plurality of holes 5 , and the plurality of protrusions 9 may form a three-dimensional surface on the first surface 3 of the first layer 1 of the top sheet 24 .

[0105] Alternatively, the protrusions 9 may extend outwardly from the second surface 4 of the first layer 1. In this case, the protrusions 9 may be referred to as "recesses". The term "recesses" corresponds to protrusions of the top sheet that face away from the wearer's skin when the top sheet is incorporated into the absorbent article. The plurality of landing areas 8, the plurality of holes 5, and the plurality of protrusions 9 may form a three-dimensional surface on the second surface 4 of the first layer 1 of the top sheet 24.

[0106] Most of the protrusions 9 may be hollow.

[0107] When viewed from the first surface 3 of the first layer 1 , most of the protrusions 9 may protrude from the landing area 8 of the first layer 1 in the same direction.

[0108] When the topsheet described herein is incorporated into an absorbent article, the plurality of projections may project toward the skin of the wearer and away from the absorbent core of the absorbent article when the article is in use.

[0109] Alternatively, when the topsheet described herein is incorporated into an absorbent article, the plurality of projections may project toward the absorbent core of the absorbent article.

[0110] When viewed in cross-section, ie, along the Z direction, most of the protrusions 9 may have any suitable shape, including but not limited to: cylindrical, bulbous, conical and mushroom-shaped.

[0111] When viewed from above, most of the protrusions 9 may have any suitable shape including, but not limited to, circular, dome-shaped, diamond-shaped, rounded diamond-shaped, oval-shaped, clover-shaped, triangular-shaped, teardrop-shaped, and elliptical protrusions.

[0112] Most of the protrusions 9 may include an internal void volume 14, which is the portion of the protrusion that does not include any fibers or only includes very few fibers. The void volume 14 can improve the breathability of the top sheet. Most of the protrusions 9 can provide void volume to receive body fluids.

[0113] This three-dimensional first layer of the top sheet provides better softness to the top sheet. It also helps to keep the wearer's skin away from body fluids in the landing area, because the protrusions essentially form a space between the wearer's skin and the body fluids.

[0114] Second floor :

[0115] The topsheet may further include a second layer including a first surface, an opposing second surface, such that the first surface of the second layer is in face-to-face relationship with the second surface of the first layer.

[0116] All aspects of the above-mentioned first layer are also applicable to the second layer in the topsheet comprising the first layer and the second layer.

[0117] The second layer can be a woven or nonwoven web of natural fibers, synthetic fibers, or a combination of natural and synthetic fibers. In one embodiment, the second layer comprises thermoplastic fibers.

[0118] The natural fibers may be selected from wheat straw fibers, rice straw fibers, flax fibers, bamboo fibers, cotton fibers, jute fibers, hemp fibers, sisal fibers, bagasse fibers, yucca fibers, miscanthus fibers, marine or freshwater algae / seaweed fibers, and combinations thereof.

[0119] The list of synthetic fibers corresponds to the list disclosed above for the topsheet and the first layer.

[0120] The second layer may have a plurality of holes that are at least partially aligned with the holes of the first layer. All holes of the second layer may be aligned with the holes of the first layer. This may be achieved by forming the holes of the first layer and the second layer simultaneously after the first layer and the second layer have been arranged in a face-to-face relationship.

[0121] See also Figures 6 to 7B , the first layer 1 can at least partially penetrate the second layer 2 of the top sheet 24 at the hole 5. This property can be enhanced according to the following method.

[0122] Alternatively, the first layer may not penetrate the second layer of the topsheet at the aperture. This feature may be formed using an alternative method such as that described in US5628097 or by using a hole punch.

[0123] Each of the holes 5 in the second layer has a side wall 6. The side wall 6 may extend outwardly away from the landing area 12 of the second surface of the second layer, such as Figures 6 to 7B When the top sheet described herein is incorporated into an absorbent article, the direction of the sidewalls of the apertures may be toward the absorbent core of the absorbent article as they extend outward. The sidewalls of the apertures may extend at least 0.1 mm beyond the second surface of the second layer, or at least 0.2 mm beyond the second surface of the second layer. The sidewalls of the apertures may form a funnel or channel.

[0124] When the topsheet described herein is incorporated into an absorbent article, these sidewalls can be oriented toward the absorbent core of the absorbent article, or can be oriented toward the skin of the wearer when the article is in use.

[0125] The description related to the holes corresponds to the description related to the holes disclosed above for the first layer.

[0126] See also Figure 6 , the top sheet 24 may include a first layer 1 and a second layer 2. The first layer may include a first surface 3 and a second surface 4. The second layer may include a first surface 10 and a second surface 11.

[0127] The first surface 10 of the second layer 2 may be in contact with the second surface 4 of the first layer 1 .

[0128] The second layer 2 may have a plurality of holes 5. The first layer 1 may have a plurality of holes 5. The second layer 2 may have a plurality of holes 5 that are at least partially or completely aligned with the holes 5 of the first layer 1. The holes 5 of the first layer 1 and the second layer 2 may be identical. The plurality of holes 5 of the second layer 2 may have the same width and / or length as the holes 5 of the first layer 1.

[0129] The second layer 2 may include landing areas 12 between the majority of the holes 5. The landing areas 8 of the first layer 1 may be aligned with the landing areas 12 of the second layer 2.

[0130] The landing area 12 of the second layer 2 may completely surround the holes 5 of the first layer 1 and the second layer 2 .

[0131] The landing area 12 of the second layer 2 may be a substantially flat area.

[0132] The land areas 8 , 12 in the first and second layers 1 , 2 may together form a substantially continuous grid through the first and second layers 1 , 2 , whereas the holes 5 may be discrete elements dispersed throughout the first and second layers 1 , 2 .

[0133] In one embodiment, the second surface of the second layer has at least one non-porous region that does not have pores and has a second non-porous region contact angle that is no greater than the first non-porous region contact angle.

[0134] The first layer and the second layer may contact each other and may be joined to each other at the non-aperture area and / or the aperture 5 .

[0135] The first and second layers may be joined together or attached to each other by mechanical bonding, adhesive bonding, pressure bonding, thermal bonding, passing hot air through the two layers, or by other bonding methods to form a topsheet as is known in the art.

[0136] In one embodiment, the first layer is attached to the second layer in the bonding area by a hot melt adhesive.Having a hydrophilic hot melt adhesive attaching the first and second layers can help to have low liquid slippage.

[0137] In one embodiment, the first layer partially interpenetrates the second layer in the pores, wherein the first layer penetrates into the pores, and is hydrophobized. With this feature, the first layer having a higher contact angle can act as a barrier to prevent fluid from flowing back from the second layer and the absorbent core, so that back seepage caused by fluid flowing back from the second layer and the absorbent core can be reduced or prevented. In addition, see Figure 6 , the second layer is not completely covered by the first layer in the hole, and the second layer is exposed in the area adjacent to the bottom edge of the hole. With such features, even if the first layer in the hole has a higher contact angle, the second layer in the hole with a lower contact angle and hydrophilicity still helps the liquid pass through the hole.

[0138] See also Fig. 7A , the top sheet may include a three-dimensional first layer 1 and a flat second layer 2. The first layer may include a first surface 3 and a second surface 4. The second layer may include a first surface 10 and a second surface 11.

[0139] The first surface 10 of the second layer 2 may be in contact with and bonded to the second surface 4 of the first layer 1 .

[0140] The first layer 1 may have a plurality of protrusions 9 protruding from the landing area 8 of the first layer 1 of the top sheet 24. Most of the protrusions 9 may include an internal void volume 14, which is the portion of the protrusion that does not include any fibers or only includes very few fibers. The void volume 14 can improve the breathability of the top sheet.

[0141] See also Figure 7B , the top sheet 24 can be a laminate comprising the first layer 1 as described above and the second layer 2 as described above in a face-to-face relationship. In other words, the first layer 1 and the second layer 2 are joined to form a laminate.

[0142] The first layer 1 and the second layer 2 are aligned in a face-to-face relationship such that the second surface 4 of the first layer 1 contacts the first surface 10 of the second layer 2. The first layer 1 and the second layer can be mechanically deformed and combined simultaneously to provide a top sheet having holes and optional protrusions. This means that both the first layer 1 and the second layer 2 can be mechanically deformed and combined together simultaneously.

[0143] When the first and second layers comprise a plurality of protrusions 9, the plurality of protrusions 9 of the first layer may be at least partially aligned or fully aligned with the plurality of protrusions 9 of the second layer 2. The protrusions 9 of the first layer 1 and the second layer 2 may be identical.

[0144] The first layer 1 and the second layer 2 may include a plurality of depressions. The holes 5 may be located between most of the depressions and / or within most of the depressions. Some depressions may not have holes 5 therein.

[0145] The plurality of depressions of the first layer may be aligned with the plurality of depressions of the second layer. The plurality of depressions of the first layer and the second layer may be identical. The first layer and the second layer may contact each other at the depressions.

[0146] When the top sheet described herein is incorporated into an absorbent article, the first surface 3 of the first layer 1 faces the body of the wearer during use of the article, and the second surface 4 of the first layer 1 faces the backsheet. When the top sheet comprises a first layer 1 and a second layer 2, the first layer 1 faces the body of the wearer, and the second layer 2 faces the backsheet.

[0147] Absorbent core

[0148] As used herein, the term "absorbent core" refers to the following components, which are used or intended to be used in absorbent articles, and which include absorbent material and optional core wrap. As used herein, the term "absorbent core" does not include a top sheet, a back sheet, and any acquisition-distribution layer or multi-layer system, which are not an integral part of the absorbent core. The absorbent core is typically a component of an absorbent article that has the largest absorption capacity among all the components of the absorbent article. The terms "absorbent core" and "core" are used interchangeably herein. The absorbent core can be manufactured to have a wide variety of sizes and shapes, and can be molded to have different thicknesses, hydrophilicity gradients, superabsorbency gradients, densities, or average basis weights at different locations across the surface of the product.

[0149] See also Figures 1 to 3 The absorbent core 28 can absorb and contain the liquid received by the absorbent article and contains an absorbent material 60 (in Figure 1 See Figures 2 to 3 , the absorbent core 28 may include a channel 29 containing no absorbent material, through which the top side 56 of the core wrap is bonded to the bottom side 58 of the core wrap. Of course, this is entirely optional, and the absorbent core may also have no bonded channels, or even no unbonded channels. The absorbent core may be rectangular, but often has a shaped area that is tapered in the area around the transverse centerline 90.

[0150] The absorbent material includes liquid-absorbent materials commonly used in disposable absorbent articles, such as comminuted wood pulp (commonly referred to as airfelt or fluff). Other examples of suitable liquid-absorbent materials include creped cellulose wadding; meltblown polymers, including coform meltblown polymers; chemically stiffened, modified or crosslinked cellulose fibers; tissue (including tissue wraps and tissue laminates), absorbent foams, absorbent sponges, superabsorbent polymers, absorbent gelling materials, or any other known absorbent material or combination of materials.

[0151] The absorbent material in the absorbent core can be any type. It can be an air-permeable felt core comprising lignocellulose fibers such as pulp fibers mixed with SAP, or an air-permeable felt core without such cellulose fibers. The air-permeable felt core generally comprises 40% to 80% SAP. For the absorbent core comprising a relatively high proportion of SAP at least partially encapsulated in the core wrapper, the SAP content can specifically represent at least 80%, 85%, 90%, 95% and at most 100% superabsorbent polymer by weight of the absorbent material. By weight of the absorbent material, the absorbent material can specifically not comprise or only comprise a small amount of cellulose fibers, such as less than 20%, specifically less than 10%, 5% or even 0% cellulose fibers. The absorbent core can comprise at least 80%, at least 90%, at least 95% or at least 99% absorbent material by weight of the absorbent core. The term "superabsorbent polymer" (abbreviated herein as "SAP") refers herein to an absorbent material that may be a cross-linked polymer and that is typically capable of absorbing at least 10 times their own weight of a 0.9% saline solution when measured using the Centrifuge Retention Capacity (CRC) test (EDANA method WSP 241.2-05E). The SAP may specifically have a CRC value of more than 20 g / g, or more than 24 g / g, or from 20 g / g to 50 g / g, or from 20 g / g to 40 g / g, or from 24 g / g to 30 g / g. The SAP may typically be in particulate form (superabsorbent polymer particles), but it is not excluded that other forms of SAP may be used, such as, for example, superabsorbent polymer foam.

[0152] Negatives

[0153] The backsheet covering the underside of the absorbent core prevents the fluid in the absorbent core from wetting articles that contact the sanitary napkin, such as underwear. Thus, the backsheet can be made of a liquid-impermeable film or a liquid-impermeable but vapor-permeable film / nonwoven laminate, a microporous film, an apertured formed film, or other vapor-permeable or rendered vapor-permeable polymeric film but substantially impermeable to fluids.

[0154] Method for treating nonwoven fabrics with a treatment composition

[0155] When the holes in the nonwoven fabric include a treatment agent, the treatment agent can be applied to the nonwoven fabric using well-known methods such as a pin aperturing process and via a printing process. The treatment agent can be applied to the nonwoven fabric simultaneously with forming holes in the nonwoven fabric using, for example, a pin aperturing process, which includes the following steps: a) providing a first layer including cellulose-based fibers, a first surface, and an opposing second surface; b) providing an aperturing apparatus including a first forming member and a second forming member engaged with the first forming member, wherein the first forming member includes a plurality of pins on its surface, and the second forming member includes a plurality of grooves on its surface; c) wetting the pins on the first forming member with the treatment agent; and d) moving the first layer between the first forming member and the second forming member so that holes are formed in the first layer when the pins on the first forming member engage with the grooves on the second forming member and treating the holes with the treatment agent. When the nonwoven fabric comprises a first layer and a second layer, a first layer comprising cellulose-based fibers, a first surface and an opposite second surface, and a second layer comprising a first surface and an opposite second surface are provided, so that the first surface of the second layer is in a face-to-face relationship with the second surface of the first layer to perform step d), so that holes are formed on both the first layer and the second layer in step d).

[0156] For example, a perforated pin process to form the holes and treat the holes with a treatment agent may correspond to a process with three rollers, wherein a first roller picks up the treatment agent from a container containing the treatment agent and transfers it to an intermediate roller comprising a hole forming element. The intermediate roller intermeshes with a third roller to form holes in the nonwoven fabric while wetting the sidewalls of the holes. A vacuum roller may be used to remove excess hydrophobic surfactant. See Figure 8, prepare the treatment composition and store it in the soaking tank 808. The first roller 802 is placed in the soaking tank 808 so as to be at least partially immersed in the treatment agent in the soaking tank 808, so that when the first roller 802 passes through the treatment agent, a certain amount of the treatment agent can be picked up and brought to the surface of the first roller 802. The first roller 802 may include an elastic or compressible surface (such as rubber) to effectively hold a certain amount of the treatment agent. The first forming member (in this case, the second roller 804) includes a plurality of hole forming elements (such as pins). The second forming member (in this case, the third roller 806) includes a plurality of grooves. The hole forming elements in the first forming member 804 are mutually engaged with the grooves in the second forming member 806. The first layer 1 from the reel or other means is fed between the first forming member 804 and the second forming member 806. When the first nonwoven layer is fed between the first forming member 804 and the second forming member 806, the first forming member 804 can contact the first nonwoven layer 1 with the hole forming elements of the first forming member 804 and the treatment agent thereon. When the first nonwoven layer 1 contacts the hole-forming element of the first forming member 804, the first forming member 804 together with the second forming member 806 forms holes in the first nonwoven layer 1 while wetting the sidewalls of the holes with the treatment agent. Optionally, the second layer 2 from a reel or other means can be fed between the first forming member 804 and the second forming member 806 together with the first layer 1, so that the first layer 1 and the second layer 2 are in a face-to-face relationship, so that holes are formed through the first layer 1 and the second layer 2 and the sidewalls of the holes are coated with the treatment agent.

[0157] The treating agent may have an HLB value of no greater than about 13.

[0158] By treating the pores with a treatment having an HLB value of no greater than about 13, which results in areas such as the perimeter and sidewalls of the pores being coated with the treatment, the coated areas become hydrophobic or less hydrophilic than the non-porous areas of the first surface of the first layer. Fluids are less likely to be absorbed by the fibers or trapped between the fibers in these areas, which can result in a reduction in fluid re-wet and a reduction in stain size. On the other hand, the non-porous areas remain hydrophilic and the negative impact on acquisition speed is minimized.

[0159] Thus, a topsheet as disclosed herein can provide reduced rewet and a light-transmitting surface on the wearer-facing surface of an absorbent article without compromising rapid liquid acquisition.

[0160] Measurement

[0161] 1. Contact angle test

[0162] Cut out a rectangular sample measuring 1cm × 2cm from the raw material nonwoven fabric or the top sheet of a disposable absorbent product, being careful not to touch the sample surface or damage the structure of the material. The sample has a length (2cm) aligned with the longitudinal centerline of the product. Use tweezers to clamp the edge of the sample and gently handle the sample, and use double-sided tape to flatten the sample on the SEM sample holder and fix it with carbon glue, with the skin-facing side facing up. Use a small hobby pneumatic spray gun device to spray the sample with a fine mist of water droplets. The water used to generate the droplets is distilled deionized water with a resistivity of at least 18MΩ-cm. Adjust the spray gun so that the droplets each have a volume of about 2pL. Approximately 0.5mg of water droplets are evenly and gently deposited on the sample. After applying the water droplets, the placed sample is immediately immersed in liquid nitrogen for freezing. After freezing, the samples were transferred to a QuorumPP3010T Cryo-SEM preparation chamber at -150°C, coated with Pt, and transferred to a Hitachi Ethos NX5000 Cryo-SEM chamber at -150°C. High-resolution images of the droplets on the fibers were obtained using a Hitachi Ethos NX5000 Cryo-SEM or equivalent instrument. Droplets were chosen randomly, but were only suitable for imaging if their orientation in the microscope was such that the projection of the droplet extending from the fiber surface was approximately maximized. The contact angle between the droplet and the fiber was determined directly from the images taken and was Fig.10 The middle part is shown as line 3700.

[0163] Such a method is performed on a non-porous area of ​​the first surface of the first layer to measure the first non-porous area contact angle. Ten individual droplets located on the middle of the non-porous area between two adjacent pores are imaged, thereby making twenty contact angle measurements (one measurement on each side of each imaged droplet), and the arithmetic mean of these twenty contact angle measurements is calculated and reported as the first non-porous area contact angle.

[0164] Such a method was also performed on wells to measure the well contact angle. Forty contact angle measurements were made (one measurement on each side of each imaged droplet) by imaging ten individual droplets near the top of three separate wells and ten droplets near the bottom of the same three separate wells, and the arithmetic mean of these forty contact angle measurements was calculated and reported as the well contact angle.

[0165] 2. Artificial Menstrual Fluid ("AMF") Preparation

[0166] AMF consists of a mixture of defibrinated sheep blood, phosphate buffered saline solution and a mucus component and has a viscosity between 7.15 cSt and 8.65 cSt at 23°C ± 1°C.

[0167] The viscosity on the AMF is performed using a low viscosity rotational viscometer such as a Cannon LV-2020 RotaryViscometer (Cannon Instrument Co., State College, US) with a UL adapter or equivalent. A spindle of appropriate size within the viscosity range is selected and the instrument is operated and calibrated according to the manufacturer. Measurements are made at 23°C ± 1°C and at 60 rpm. Results are reported to the nearest 0.01 cSt.

[0168] Defibrinated sheep blood

[0169] Defibrinated sheep blood (purchased from Cleveland Scientific, Inc., Bath, OH, US) or equivalent collected under sterile conditions with a packed cell volume of 38% or greater was used.

[0170] Phosphate buffered saline solution

[0171] Phosphate buffered saline solution consists of two separately prepared solutions (Solution A and Solution B). To prepare 1L of Solution A, add 1.38 ± 0.005g sodium phosphate monobasic monohydrate and 8.50 ± 0.005g sodium chloride to a 1000mL volumetric flask and add distilled water to the volume. Mix thoroughly. To prepare 1L of Solution B, add 1.42 ± 0.005g sodium phosphate dibasic anhydrous and 8.50 ± 0.005g sodium chloride to a 1000mL volumetric flask and add distilled water to the volume. Mix thoroughly. Add 450 ± 10mL of Solution B to a 1000mL beaker and stir at low speed on a stir plate. Insert a calibrated pH probe (accurate to 0.1) into the beaker of Solution B and add enough Solution A while stirring to bring the pH to 7.2 ± 0.1.

[0172] Mucus components

[0173] The mucus component is a mixture of phosphate buffered saline solution, potassium hydroxide aqueous solution, gastric mucin and lactic acid aqueous solution. The amount of gastric mucin added to the mucus component directly affects the final viscosity of the prepared AMF. The successful range of gastric mucin is usually between 38 grams and 50 grams. To prepare about 500 mL of the mucus component, 460 ± 10 mL of the previously prepared phosphate buffered saline solution and 7.5 ± 0.5 mL of 10% w / v potassium hydroxide aqueous solution are added to a 1000 mL heavy glass beaker. The beaker is placed on a stirring hot plate and the temperature is raised to 45°C ± 5°C while stirring. A predetermined amount of gastric mucin (± 0.50 g) is weighed and slowly sprinkled into the previously prepared liquid that has reached 45°C without agglomeration. Cover the beaker and continue mixing. Within 15 minutes, the temperature of the mixture is brought to above 50°C, but not more than 80°C. While maintaining this temperature range, heating was continued for 2.5 hours with gentle stirring, after which the beaker was removed from the hot plate and cooled to below 40°C. Next, 1.8 ± 0.2 mL of 10% v / v lactic acid aqueous solution was added and mixed thoroughly. The mucus component mixture was autoclaved at 121°C for 15 minutes and cooled for 5 minutes. The mucus component mixture was removed from the autoclave and stirred until the temperature reached 23°C ± 1°C.

[0174] Allow the temperature of the sheep blood and mucus components to reach 23°C ± 1°C. Using a 500mL graduated cylinder, measure the volume of the entire batch of the mucus component and add it to a 1200mL beaker. Add an equal amount of sheep blood to the beaker and mix thoroughly. Using the viscosity method described previously, ensure that the viscosity of the AMF is between 7.15cSt – 8.65cSt. If not, dispose of the batch and make another batch as needed for adjusting the mucus component.

[0175] Unless intended for immediate use, qualified AMF should be refrigerated at 4°C. After preparation, AMF may be stored in an airtight container at 4°C for up to 48 hours. Prior to testing, the AMF must be brought to 23°C ± 1°C. After testing is complete, discard any unused portion.

[0176] 3. Back-infiltration test

[0177] For absorbent articles loaded with artificial menstrual fluid (AMF) as described herein, rewet is measured.

[0178] After dispensing 3.0 ml, 6.0 ml and 9.0 ml of AMF, the amount of fluid remaining on the topsheet under 0.1 psi pressure, i.e., rewet, was measured.All measurements were performed in a laboratory maintained at 23°C ± 2°C and 50% ± 2% relative humidity.

[0179] Remove the test product from all packaging, being careful not to press or pull the product while handling. Do not attempt to smooth out wrinkles. Condition the test product at 23°C ± 2°C and 50% ± 2% relative humidity for at least 2 hours prior to testing.

[0180] Place the test product on a flat, level surface with the body side facing up and load the strikethrough plate in the center of the test product to apply 0.25 psi pressure on the test product.

[0181] See also 9A to 9E , the strike-through plate 9001 is constructed of plexiglass with an overall size of 10.2 cm long by 10.2 cm wide by 3.2 cm high. The longitudinal channel 9007 extending along the length of the plate is 13 mm deep and 28 mm wide at the top plane of the plate, with the side walls sloping down at 65° to a 15 mm wide base. The central test fluid well 9009 is 26 mm long, 24 mm deep and 38 mm wide at the top plane of the plate, with the side walls sloping down at 65° to a 15 mm wide base. At the bottom of the test fluid well 9009, there is an "H" shaped test fluid reservoir 9003, which leads to the bottom of the plate to introduce fluid to the article below. The test fluid reservoir 9003 has a total length ("L") of 25 mm, a width ("W") of 15 mm, and a depth ("D") of 8 mm. The longitudinal legs of the reservoir are 4 mm wide and have rounded ends with a radius 9010 of 2 mm. The legs are 3.5 mm apart. The center post has a radius 9011 of 3 mm and accommodates opposing electrodes 9004 that are 6 mm apart. The sides of the reservoir are arched outward at a radius 9012 of 14 mm defined by an overall width W of 15 mm. Two wells 9002 (80.5 mm long x 24.5 mm wide x 25 mm deep) located outside the lateral channels are filled with lead shot to adjust the overall mass of the plate to provide 0.25 psi (17.6 gf / cm 2 ) of the restraining pressure. Electrode 9004 is embedded in plate 9001, thereby connecting the external banana-shaped socket 9006 to the inner wall of fluid reservoir 9003. The circuit interval timer is inserted into the socket 9006 to the inner wall 9005 of fluid reservoir 9003.

[0182] Use a pipette to carefully distribute 3.0ml of AMF to the center of the test article through the perforation of the strike-through plate within 2 seconds. Once the gushing flow is obtained, the plate is removed and the timer is started for 3 minutes. After removing the plate, the image of the top sheet of the test product is quickly obtained using a color scanner HPScanjet G4010 or equivalent, and the scanner surface is cleaned after each scan. In the stain size test described below, the image will be analyzed to measure the stain size on the top sheet. At the end of 3 minutes, 5 filter papers (typical laboratory filter papers, such as Ahlstrom #63212.7cm×12.7cm filter papers) weighed in advance (referred to as "dry weight") are placed on the top of the approximate center of the area contaminated with fluid. Apply the required mass to produce a pressure of 0.1psi on the top of the test product, and keep it under pressure for 5 seconds. Weigh the filter paper again (referred to as "wet weight"). The difference between the wet weight and dry weight of the filter paper is the light pressure back infiltration under the amount of fluid added.

[0183] Repeat the above steps until a total of 9.0 ml of fluid has been dispensed onto the test product.Report the backwet values ​​to the nearest 0.001 gram for the 3.0 ml, 6.0 ml and 9.0 ml gush levels.

[0184] In a similar manner, a total of three replicates were tested for each test product to be evaluated. The light pressure re-bleed was reported as the arithmetic mean of the replicates to the nearest 0.001 gram.

[0185] 4. Stain size test

[0186] The area of ​​stain visible on the topsheet of the absorbent article due to fluid remaining on the topsheet was measured on the topsheet images of the test products obtained in the above-described Rewet Test for gush levels of 3.0 ml, 6.0 ml and 9.0 ml.

[0187] Image analysis was performed using an image analysis program such as Image J software (version 1.52p or above, National Institute of Health, USA) or equivalent. Images were distance calibrated with a ruler image to give an image resolution of 7.95 pixels per millimeter.

[0188] Open the top sheet image in Image J. Set the scale according to the image resolution. Crop the image in the center region to make a minimum bounding rectangle selection around the entire stain area visible on multiple cushion layers. Convert the image type to 8-bit. Apply a Gaussian Blur filter to smooth the image with a Gaussian function with a Sigma (radius) of 2. Then convert the filtered 8-bit grayscale image to a binary image using the “minimum” thresholding method to find the boundaries of the stain area on the top sheet (caused by fluid left on the top sheet) relative to the lighter colored stain area from subsequent layers.

[0189] Obtain the area of ​​the selected stain area on the topsheet and record it as the topsheet stain size to the nearest 0.01 cm 2 Repeat this entire process for three substantially similar parallel articles. The value reported is the average of three individually recorded measurements of topsheet stain size, accurate to 0.01 cm 2 .

[0190] 5. Collection time test

[0191] The acquisition time of absorbent articles loaded with AMF as described herein was measured using a strike-through plate and an electronic circuit interval timer. The time required for the absorbent article to acquire one dose of AMF was recorded. All measurements were performed in a laboratory maintained at 23°C ± 2°C and 50% ± 2% relative humidity.

[0192] See also 9A to 9E, the strike-through plate 9001 is constructed of plexiglass with an overall size of 10.2 cm long by 10.2 cm wide by 3.2 cm high. The longitudinal channel 9007 extending along the length of the plate is 13 mm deep and 28 mm wide at the top plane of the plate, with the side walls sloping down at 65° to a 15 mm wide base. The central test fluid well 9009 is 26 mm long, 24 mm deep and 38 mm wide at the top plane of the plate, with the side walls sloping down at 65° to a 15 mm wide base. At the bottom of the test fluid well 9009, there is an "H" shaped test fluid reservoir 9003, which leads to the bottom of the plate to introduce fluid to the article below. The test fluid reservoir 9003 has a total length ("L") of 25 mm, a width ("W") of 15 mm, and a depth ("D") of 8 mm. The longitudinal legs of the reservoir are 4 mm wide and have rounded ends with a radius 9010 of 2 mm. The legs are 3.5 mm apart. The center post has a radius 9011 of 3 mm and accommodates opposing electrodes 9004 that are 6 mm apart. The sides of the reservoir are arched outward at a radius 9012 of 14 mm defined by an overall width W of 15 mm. Two wells 9002 (80.5 mm long x 24.5 mm wide x 25 mm deep) located outside the lateral channels are filled with lead shot to adjust the overall mass of the plate to provide 0.25 psi (17.6 gf / cm 2 ) of the restraining pressure. Electrodes 9004 are embedded in plate 9001, thereby connecting an external banana-shaped socket 9006 to the inner wall of fluid reservoir 9003. A circuit interval timer is inserted into the socket 9006 to the inner wall 9005 of fluid reservoir 9003. A circuit interval timer (not shown in the drawings) is inserted into the socket 9006 and monitors the impedance between the two electrodes 9004 and measures the time from the introduction of AMF into reservoir 9003 until the AMF is discharged from the reservoir. The timer has a resolution of 0.01 seconds.

[0193] Remove the test product from all packaging, being careful not to press or pull the product while handling. Do not attempt to smooth out wrinkles. Condition the test specimens at 23°C ± 2°C and 50% ± 2% relative humidity for at least 2 hours prior to testing.

[0194] The required mass of the strike-through panel must be calculated for the specific dimensions of the test article so that a confining pressure of 1.72 kPa is applied. Determine the longitudinal midpoint and lateral midpoint of the absorbent core of the article. Measure and record the lateral width of the core to the nearest 0.1 cm. The required mass of the strike-through panel is calculated as the core width multiplied by the strike-through panel length (10.2 cm) multiplied by 17.6 gf / cm 2 , and record the required mass to the nearest 0.1 g. Add lead pellets to the plate to obtain the calculated mass.

[0195] Connect the electronic circuit interval timer to the strike-through plate 9001 and reset the timer to zero. Place the test product on a flat, level surface with the body side facing up. Gently place the strike-through plate 9001 onto the center of the test product to ensure that the "H" shaped reservoir 9003 is centered over the test area.

[0196] Using a mechanical pipette, 3.00 mL ± 0.05 mL of AMF was accurately drawn into the test fluid reservoir 9003. In 3 seconds or less, the fluid was dispensed along the molded lip at the bottom of the reservoir 9003 without splashing. After the fluid had been collected, the collection time was recorded to the nearest 0.01 second. The electrodes 9004 were fully cleaned before each test.

[0197] In a similar manner, test a total of three replicates for each test product to be evaluated. Report the acquisition time (seconds) as the average of the replicates to the nearest 0.01 second.

[0198] 6. Non-hole area size measurement

[0199] (A) Sample preparation

[0200] When nonwoven fabrics are available in raw material form, samples of 55 mm × 55 mm in size are cut from the raw material. When nonwoven fabrics are parts of a finished product, a razor blade is used to remove the nonwoven fabrics from the finished product to cut the nonwoven fabrics from other parts of the finished product to provide a nonwoven fabric sample of 55 mm × 55 mm in size. If necessary, a freezer spray (such as Cyto-Freeze, Control Company, Houston TX) can be used to remove the nonwoven fabric sample from other parts of the finished product.

[0201] (B) Image generation

[0202] Under uniform surface illumination conditions, the nonwoven sample is placed flat on a dark background. Use an optical microscope (such as Keyence 3D Measurement System VR-3200) or equivalent to scan the entire area of ​​the sample. Use an image analysis program (such as ImageJ software (version 1.52p or above, National Institutes of Health, USA) and equivalents to perform analysis, such as area ratio measurement. The image needs to be calibrated with the image of the ruler to give the image resolution. Set the scale according to the image resolution and select a field size of 55mm×55mm for the nonwoven sample.

[0203] (C) Image analysis - creating binary images

[0204] Open the sample image in ImageJ. Convert the image type to 8-bit. The 8-bit grayscale image is then converted to a binary image (where "black" foreground pixels correspond to holes) using the "minimum" thresholding method: If the histogram of gray level (GL) values ​​(ranging from 0 to 255, each gray level value i has a tendency P i The bin has exactly two local maxima, then the gray level threshold t is defined as P under this value. t-1 > P t And P t ≤ P t+1 If the histogram has more than two local maxima, the histogram is iteratively smoothed using a windowed arithmetic mean of size 3, and this smoothing is performed iteratively until there are exactly two local maxima. The grayscale value threshold t is defined as the value P at which t-1 > P t And P t ≤ P t+1 The procedure identifies the gray level (GL) value of the smallest population located between the dark pixel peaks of the pores and the lighter pixel peaks of the sample material. If the histogram contains zero or one local maximum, the method cannot proceed and no output parameters are defined.

[0205] (D) Size of non-hole area

[0206] The filtered image is created by removing small openings or defects in the binary image using an outlier removing median filter which replaces a pixel with the median value of the surrounding area with a radius of, for example, 5 pixels if the pixel is darker than the surrounding pixels. An inverted image is created so that discrete non-hole areas have a pixel value of 255.

[0207] Apply the ImageJ plugin "Local Thickness" to the image. Local thickness analysis measures the diameter of the largest sphere that fits inside the object and contains each point (i.e., foreground pixel in the image). (Reference "New algorithms for Euclidean distance transformation on an n-dimensional digitized picture with applications", T. Saito and J. Toriwaki, Pattern Recognition 27, 1994, 1551-1565). Convert the image type of the local thickness map to 16 bits.

[0208] The ImageJ plugin "k-means Clustering" was applied to the images obtained above, which segments the images into a defined number of clusters with similar intensities. The options for k-means clustering used in this analysis were: 5 clusters (i.e., the image was divided into 5 segments); a cluster center tolerance of 0.0001; randomization seed enabled (randomization seed: 48); clusters displayed as centroid values. The image of the clusters represented by the centroid values ​​was used and segmented via centroid value thresholding to select only discrete non-hole areas. The histogram data of the binary image was used to calculate the area ratio (%) of the discrete non-hole areas by dividing the count of foreground pixels (corresponding to the discrete non-hole areas) by the total number of pixels of the entire area of ​​the image and multiplying it by 100%. This value is reported to the nearest 1%. The same image was also used for size / area analysis. The scale was set according to the image resolution. If necessary, watershed segmentation was used to separate discrete non-hole areas that were in contact with each other. When incomplete areas on the edge of the image were excluded, the area (mm) of each discrete non-hole area was measured. 2 The size / area of ​​the discrete non-porous regions is the arithmetic mean of the area values ​​and is reported to the nearest 1 mm. 2 .

[0209] Example

[0210] Example 1: Nonwoven Substrate Preparation

[0211] Using 35 gsm 100% hydrophilic cotton spunlace nonwoven fabric (Xiamen Yanjiang New Materials Co., Ltd., China) as the first layer and 30 gsm carded air-permeable nonwoven fabric made of 4D hydrophilic PE / PET fibers as the second layer, various apertured nonwoven substrates were prepared as shown in Table 1 below. All nonwoven substrates were apertured to form Fig.11 When viewed from the first surface 3 of the first layer, Fig.11 The pattern in FIG. 1 has holes 5 and non-hole areas 8. It has a size of about 78 mm as measured by the non-hole area size measurement method. 2 The non-hole area size.

[0212] The nonwoven fabric has a first surface 3, a plurality of pores 5, and a plurality of discrete non-porous areas (in this case, land areas 8). While the pores are being formed, substrates 1 and 3 are perforated and the pores are coated with a beeswax emulsion (FX-211, Xiamen Bondeli Chemical Technology Co., Ltd., China).

[0213] Table 1

[0214]

[0215] Example 2: Nonwoven properties

[0216] The contact angle of the non-pore area in the first surface of the first layer in each nonwoven substrate prepared in Example 1 ("first non-pore area contact angle") and the contact angle of the sidewall of the pore ("pore contact angle") were measured according to the contact angle test disclosed herein. Table 2 below includes the measurement results.

[0217] Table 2

[0218]

[0219] Example 3. Absorbent Article

[0220] Sanitary Napkins 1 to 4 were prepared as exemplary absorbent articles having a top sheet made of the nonwoven substrate in Example 1 using a common secondary top sheet, absorbent core, and back sheet.

[0221] The Rewet, Stain Size, and Acquisition Speed ​​of each of sanitary napkins 1 through 4 were measured according to the Rewet, Stain Size, and Acquisition Speed ​​Tests disclosed herein. Table 3 below includes the measurement results.

[0222] Table 3

[0223]

[0224] Sanitary napkin 1 having substrate 1 as the topsheet exhibits significantly lower rewet and smaller stain size than sanitary napkin 2 having substrate 2 as the topsheet. In addition, sanitary napkin 1 exhibits the same acquisition time as sanitary napkin 2.

[0225] Sanitary napkin 3 with substrate 3 as the topsheet exhibited significantly lower rewet and smaller stain size than sanitary napkin 4 with substrate 4 as the topsheet, with the same fluid acquisition time, especially in the first 3 ml gush.

[0226] The dimensions and values ​​disclosed herein should not be understood as being strictly limited to the exact numerical values ​​cited. Instead, unless otherwise indicated, each such dimension is intended to represent the stated value and a functionally equivalent range around that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm".

[0227] Unless expressly excluded or otherwise limited, each document cited herein, including any cross-referenced or related patent or patent application and any patent application or patent to which this application claims priority or the benefit of, is hereby incorporated by reference in its entirety. The citation of any document is not an admission that it is prior art to any of the present invention disclosed or claimed herein, or an admission that it, by itself or in combination with any one or more of the references, proposes, suggests, or discloses any such invention. In addition, to the extent that any meaning or definition of a term in this invention conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this invention shall govern.

[0228] Although specific embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications may be made without departing from the spirit and scope of the present invention. Therefore, it is intended that all such changes and modifications within the scope of the present invention be covered in the appended claims.

Claims

1. An absorbent article having a wearer-facing surface and a garment-facing surface, the absorbent article comprising a top sheet, a back sheet, and an absorbent material layer disposed between the top sheet and the back sheet, wherein the topsheet comprises a first layer comprising cellulose-based fibers, the first layer comprising a first surface, an opposing second surface, and a plurality of apertures, wherein the first surface of the first layer forms at least a portion of the wearer-facing surface; wherein the first surface of the first layer comprises a hydrophilic non-porous region having a first non-porous region contact angle measured by a contact angle test; and Each of the pores in the majority of the pores has a sidewall having a pore contact angle measured by a contact angle test, the pore contact angle being higher than the first non-pore area contact angle.

2. The absorbent article of claim 1, wherein the aperture contact angle as measured by the Contact Angle Test is equal to or greater than about 40°.

3. An absorbent article according to claim 1 or 2, wherein the difference between the first non-aperture area contact angle and the aperture contact angle is at least about 20°.

4. The absorbent article according to any one of the preceding claims, wherein the first layer further comprises thermoplastic fibers.

5. The absorbent article according to any one of the preceding claims, wherein the non-porous area does not contain a treating agent.

6. The absorbent article according to any one of claims 1 to 5, wherein the non-porous area is treated with a hydrophilic treatment agent.

7. The absorbent article according to any one of the preceding claims, wherein the sidewall of each aperture is coated with a treatment having an HLB value of no greater than about 13.

8. The absorbent article according to any one of the preceding claims, wherein the apertures are formed by a pin punching process.

9. The absorbent article according to any one of the preceding claims, wherein the first layer comprises a plurality of protrusions extending outwardly away from the absorbent core.

10. The absorbent article of any of the preceding claims, wherein the topsheet further comprises a second layer having a first surface, an opposing second surface, and a plurality of apertures such that the first surface of the second layer is in face-to-face relationship with the second surface of the first layer.

11. The absorbent article of claim 10, wherein the second layer comprises thermoplastic fibers.

12. An absorbent article according to claim 10 or 11, wherein the second surface of the second layer comprises at least one non-porous area having a second non-porous area contact angle, the second non-porous area contact angle being no greater than the first non-porous area contact angle.

13. The absorbent article according to any one of the preceding claims, wherein the first layer is a hydraulically spunlace nonwoven layer.

14. The absorbent article according to any one of the preceding claims, wherein the apertures in the first layer have an open area of ​​at least 3%.

Images