Women's hygiene pads with foam absorbent layer and improved body fit.

Abstract

A women's hygiene pad comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent layer disposed between the top sheet and the back sheet. The absorbent layer comprises a layer of open-cell foam including arrangement of macrovoids. The arrangement of macrovoids defines paths located along the xy plane of the open-cell foam layer and includes left and right front path sections mainly located in front of the transverse axis.

Description

Technical Field

[0001] The present disclosure generally relates to feminine hygiene pads having a foam absorbent layer component, and more particularly to feminine hygiene pads having a foam absorbent layer with a macrovoid arrangement.

Background Art

[0002] Feminine hygiene pads containing an absorbent component formed of an elastic, open cell polymer foam are currently manufactured and commercially available. Incorporating an elastic open cell foam can impart cushioning, flexibility, and a comfortable feel to the pad, and in some instances can provide a relatively thin (i.e., having a relatively low thickness) pad, which is considered desirable for some consumer / user market segments, as thin and flexible pads can be relatively unobtrusive when worn under clothing as compared to pads that rely on a cellulose fiber material component for absorbency.

[0003] In the case of feminine hygiene pads, close conformity of the pad to the wearer's body is considered important for at least three purposes. Minimizing the possibility that discharged menstrual fluid can move along the skin surface and be captured and absorbed by the pad and leak (thereby soiling underwear, outerwear, bedding, etc.). Maximizing the efficient utilization of the absorbent component and function of the pad, and unobtrusiveness under clothing. However, due to the elasticity of typical open cell polymer foams, pads manufactured using such foam layer components can be somewhat resistant to bending and creasing and can have a shape memory that biases them towards their as-manufactured configuration (typically, substantially planar / flat). As a result, they can be somewhat resistant to maintaining close conformity to the complex, unlined curves and intersecting shape features of the human female body in the crotch region. For example, absorbent products having a more structured configuration with 3D shape features that provide closer body conformity (such as interlabial pads or inserts) can cause discomfort.

Summary of the Invention

[0004] Therefore, manufacturers who can provide comfortable and flexible feminine hygiene pads with improved body fit compared to currently available products can enjoy a competitive advantage in the market. [Means for solving the problem]

[0005] This disclosure solves the problem of body conformity in women's hygiene pads by providing an absorbent layer having a macrovoid arrangement that can improve the ability of the pad to closely conform to the wearer's body in the crotch area while remaining comfortable for the wearer.

[0006] This specification describes a feminine hygiene pad comprising a front end, a rear end, a longitudinal axis and a transverse axis having an intersection point, a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent layer disposed between the top sheet and the back sheet. The absorbent layer comprises a layer of open-cell foam having a thickness in the z direction and an outer circumference along the xy plane. The layer of open-cell foam includes an arrangement of macrovoids therein, the macrovoids having a depth in the z direction. The arrangement of macrovoids defines paths along the xy-plane of the open-cell foam layer, mainly located in front of the horizontal axis, beginning at a left-center position close to the axis intersection, and ending at a left-outer position located in front of the first left-center position and further out on the vertical axis than the first left-center position; and a right-front path section mainly located in front of the horizontal axis, beginning at a right-center position close to the axis intersection, ending at a right-outer position located in front of the first right-center position and further out on the vertical axis than the first right-center position.

[0007] Furthermore, this specification describes a feminine hygiene pad comprising a front end, a rear end, and longitudinal and transverse axes having intersections, a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent layer disposed between the top sheet and the back sheet. The absorbent layer includes a layer of open-cell foam having a thickness in the z direction and an outer circumference along the xy plane. The layer of open-cell foam includes an arrangement of macrovoids therein, the macrovoids having a depth in the z direction. The arrangement of macrovoids defines paths along the xy-plane of the open-cell foam layer, mainly located forward of the transverse axis, beginning at a left-center position close to the axis intersection and ending at a left-outer position located forward of the first left-center position and further outward on the longitudinal axis than the first left-center position; and mainly located forward of the transverse axis, beginning at a right-center position close to the axis intersection and ending at a right-outer position located forward of the first right-center position and further outward on the longitudinal axis than the first right-center position. The ratio of macrovoid length to void length in at least one of the left-front and right-front path sections is approximately 30:1 to approximately 1:5. [Brief explanation of the drawing]

[0008] [Figure 1] This is a plan view of an example of a women's hygiene pad with the top sheet facing the observer. [Figure 2] This is a plan view showing an example of an absorption layer. [Figure 3A] Figure 1 is a schematic cross-sectional view of a women's hygiene pad. [Figure 3B] Figure 3B is an enlarged portion of the drawing in Figure 3A, enlarged to show a sublayer of the absorption layer that may be present in some examples. [Figure 4A] This is a plan view of an example of an absorption layer with an example of macrovoid arrangement. [Figure 4B] Figure 4A is a plan view of the absorption layer, showing the path of the macrovoids. [Figure 4C] Figure 4A is a plan view of the absorption layer, showing the path of the macrovoids. [Figure 4D]Figure 4A is a plan view of the absorption layer, showing the zone of bending or displacement in the z direction around the path of the macrovoid. [Figure 4E] Figure 4D shows a cross-sectional view taken along lines 4E-4E and 4F-4F, illustrating the configuration of the absorbent layer when the pad containing the absorbent layer is worn by the wearer / user. [Figure 4F] Figure 4D shows a cross-sectional view taken along lines 4E-4E and 4F-4F, illustrating the configuration of the absorbent layer when the pad containing the absorbent layer is worn by the wearer / user. [Figure 4G] This is a plan view of an example of an absorption layer, where an example of macrovoid arrangement is combined with an example of pore arrangement. [Figure 4H] This is a plan view of another example of an absorption layer, where an example of macrovoid arrangement is combined with an example of pore arrangement. [Figure 4I] This is a plan view of an example of an absorption layer, showing the arrangement of macrovoids and an example of added reinforcing material. [Figure 5] This figure shows an example of the arrangement of macrovoids defining a forward path as described herein. [Figure 6] This diagram shows the arrangement of macrovoids that do not define a forward path, as described herein. [Figure 7] This diagram shows the arrangement of macrovoids that do not define a forward path, as described herein. [Figure 8] This figure shows an example of the arrangement of macrovoids defining a forward path as described herein. [Figure 9] This diagram shows the arrangement of macrovoids that do not define a forward path, as described herein. [Figure 10] This figure shows an example of the arrangement of macrovoids defining the backward path as described herein. [Figure 11A] This is a schematic cross-sectional view of a portion of a pad having an absorbent layer that is not folded (Figure 11A) and an absorbent layer that is folded (Figure 11B) across the entire depth of the macrovoid. [Figure 11B]Schematic cross-sectional views of a portion of a pad having an absorbent layer without creases (FIG. 11A) and an absorbent layer with creases (FIG. 11B) across the full depth of the macrovoids. [Figure 12] Schematic cross-sectional view of a part of a pad with an absorbent layer having partial-depth macrovoids.

Mode for Carrying Out the Invention

[0009] Definitions For a feminine hygiene pad opened and laid flat on a horizontal plane, "lateral" refers to a direction perpendicular to the longitudinal direction and parallel to the horizontal plane.

[0010] For a feminine hygiene pad opened and laid flat on a horizontal plane and having a length measured from a front end to a rear end, "longitudinal" refers to a direction parallel to the line along which the length is measured and parallel to the horizontal plane. "Length" refers to the dimension measured in the longitudinal direction.

[0011] For a feminine hygiene pad, the terms "front side", "rear side", "front", and "rear" relate to the positions normally worn by the user and the features or regions of the pad corresponding to the front and rear sides of the user's body when standing upright.

[0012] For a feminine hygiene pad opened and laid flat on a horizontal plane, or for a nonwoven web material laid flat on a horizontal plane, "z-direction" refers to the direction perpendicular to the horizontal plane, and any plane parallel to the horizontal plane may be referred to as the "x-y plane". When the pad is being worn by the user (and thus biased into a curved configuration), the "z-direction" at any particular point location on the pad refers to the direction perpendicular to the surface facing the wearer of the pad at the particular point location. For a nonwoven web during manufacture, "z-direction" refers to the direction perpendicular to both the machine direction and the cross-machine direction of the product, and any plane parallel to the machine direction and the cross-machine direction may be referred to as the "x-y plane".

[0013] With regard to women's hygiene pads, "facing the wearer" is a relative positional term referring to a feature of the pad's component or structure that, during use, is closer to the wearer than another feature of the component or structure located along the same z-direction. For example, the top sheet has a wearer-facing surface that is located closer to the wearer than the outward-facing surface on the opposite side of the top sheet.

[0014] In the context of women's hygiene pads, "outward-facing" is a relative positional term referring to a feature of the pad's component or structure that, during use, is further from the wearer than another feature of the component or structure located along the same z-direction. For example, the top sheet has an outward-facing surface that is located further from the wearer than the wearer-facing surface on the opposite side of the top sheet.

[0015] The terms "inside" and "outside," which indicate relative positions, refer to the position of a first feature relative to a second feature with respect to the horizontal or vertical axis of the pad or its layer component, where both features are on the same side of the axis. For example, if the first feature is closer to the vertical axis of the pad than the second feature, the first feature is "inside" the second feature in the horizontal direction, and the second feature is "outside" the first feature in the horizontal direction. Similarly, if the first feature is closer to the horizontal axis of the pad than the second feature, the first feature is "inside" the second feature in the vertical direction, and the second feature is "outside" the first feature in the vertical direction.

[0016] A “macrovoid” in a foam layer is a defined void in the layer having dimensions in the xy plane and the z direction, which is visible to the naked eye of an adult with normal vision at a distance of arm length, and is produced by either (a) removing material from the foam through a manufacturing process after the foam has been formed, or (b) shaping the foam precursor material to form macrovoids into the finished foam. Therefore, closed or open bubbles of random size and position that occur within the foam structure as a characteristic of the foam manufacturing process are not “macrovoids” for the purposes of this specification. Macrovoids may extend entirely through the z-thickness of the foam layer, or only partially through the z-thickness of the foam layer.

[0017] "Forward path of a macrovoid" (or similar expression) means any identifiable virtual straight or curved path along the xy plane of the surface of the absorption layer, having a start point and an end point, respectively, at the distal edge of a macrovoid, the start point and the end point being at least 2.5 cm apart, along which at least 50 percent, preferably at least 67 percent, and more preferably at least 75 percent of the length along which it is traversed two or more macrovoids, and along which the distance from the start point to the end point, separated by no more than 2.5 cm along the straight-line dimension, does not include any discontinuities or changes in direction greater than 30 degrees.

[0018] For illustrative purposes, Figure 5 shows a straight-ahead path 50f (shown as a dotted line) of a macrovoid 51 that conforms to this definition. Path 50f begins at the distal end of the leftmost macrovoid in the figure and ends at the distal end of the rightmost macrovoid in the figure. The length of the path is pl1, and more than 40% of its length traverses the five macrovoids 51 shown, resulting in (sum of lengths a) / pl1 > 0.50.

[0019] Figure 6 shows a path 50x that does not fit this definition because (sum of length b) / pl2 < 0.50.

[0020] Figure 7 shows a path 50x that does not fit this definition because (sum of length c) / pl3 < 0.50.

[0021] In Figure 8, assuming that the straight path dimension pd is greater than 2.5 cm and that the smaller angle α between the lines 52 tangent to the curve of the forward path 50f at each of its ends is 30 degrees or less, Figure 8 shows a curved forward path 50f of a macrovoid 51 that fits this definition. The path does not change direction by more than 30 degrees along the straight path dimension pd which is greater than 2.5 cm. The sum of the individual lengths d of the macrovoids 51 traversed by the path, divided by the length of the curved forward path 50f, is greater than 0.50.

[0022] Figure 9 shows an alternative attempt to identify suitable paths for macrovoids, similar to that shown in Figure 7. When the proposed path 50x is drawn, the portions that cross macrovoids 51, each having a maximum dimension e, are maximized, and the portions that do not cross macrovoids 51 are minimized. The sum of the maximum dimensions e divided by the total path length is greater than 0.50 at this point. However, assuming that the shown straight path dimension pd is less than 2.5 cm, Figure 9 shows a path 50x that does not fit this definition because the path changes direction by more than 30 degrees within a dimension pd of less than 2.5 cm (and does so twice). This unsuitable change of direction is repeated throughout the proposed path 50x. Therefore, even if redrawn, the proposed path 50x does not fit this definition.

[0023] "Backward path of a macrovoid" (or similar expression) means any identifiable virtual straight or curved path along the xy plane of the surface of the absorption layer, having a start point and an end point, respectively, at the distal edge of a macrovoid, the start point and the end point being at least 2.5 cm apart, along which at least 30 percent, or at least 40 percent, or at least 60 percent of the length along which it is traversed two or more macrovoids, and along the straight dimension from the start point to the end point, which are no more than 2.5 cm apart, there are no discontinuities or changes in direction greater than 30 degrees.

[0024] Figure 10 shows a path 50r that fits this definition, since (total length f) / pl4 > 0.30. As shown in Figure 10, in some configurations, a portion of the back path of the macrovoid may intersect with one or more holes 42r (as described herein).

[0025] explanation Referring to Figures 1 and 2, and Figure 3A, the women's hygiene pad 10 may include a liquid-permeable top sheet 20, a liquid-impermeable back sheet 30, and an absorbent layer 40 positioned between the top sheet and the back sheet. This absorbent layer has an outer perimeter 41. Outside the outer perimeter 41, the top sheet and the back sheet may be joined together in a laminated manner by any preferred mechanism, including but not limited to adhesive bonding, heat bonding, or pressure bonding, thereby maintaining and holding the absorbent layer 40 in place between the top sheet 20 and the back sheet 30. The absorbent layer 40 may be cut, as shown in the figures, or otherwise given a shape that is asymmetrical with respect to the transverse axis, for the purpose of enabling the separation of a continuous absorbent layer 40 from the stock material along a nested contour, providing efficient use of the absorbent layer stock material / minimizing cutting scrap. For the purpose of providing a larger surface area for blocking fluids from moving along the skin through the buttock folds, it may be preferable that the wider portion of the shape in the transverse direction be at the rear of the pad. The pad 10 may include opposing wing portions 15 that extend laterally outside the outer circumference 41 with a width dimension relatively larger than that of the main portion of the pad. The outer surface of the backsheet forming the underside of the main portion and the wing portions may have a deposit of adhesive 35 thereon. The adhesive deposit 35 is provided to allow the user to adhere the pad to the inside of the underwear in its crotch area, wrap the wing portions around the inner edge of the leg opening of the underwear and adhere them to the outside / underside of the underwear in the crotch area, and can provide an auxiliary retaining support and help protect the leg edges of the underwear from soiling. When the pad 10 is packaged, the adhesive deposit 35 may be covered with one or more sheets (not shown) of release film or paper, which cover / shield the adhesive deposit 35 from contact with and / or contamination of other surfaces until the user removes the release film or paper and places the pad for use.

[0026] Top sheet The top sheet 20 may be formed from any suitable nonwoven web material that is flexible, soft to the touch, and does not irritate the wearer's skin. Referring again to the figure, the top sheet 20 is positioned adjacent to the surface of the absorbent layer 40 facing the wearer and may be bonded thereto and to the back sheet 30 by any preferred attachment or bonding method. The top sheet 20 and the back sheet 30 may be directly bonded to each other in the peripheral region outside the peripheral portion 41 of the absorbent layer 40, or indirectly bonded by directly bonding to the wearer-facing surface and the outward-facing surface of the absorbent layer, or to any additional optional layer included in the pad, respectively.

[0027] A suitable top sheet material includes a liquid-permeable material that is comfortable when in contact with the wearer's skin and allows discharged menstrual fluid to rapidly permeate through it. Suitable top sheets can be made from a variety of materials, such as nonwoven web materials.

[0028] Non-limiting examples of nonwoven web materials that may be suitable for use as a top sheet include fibrous materials made from natural fibers, modified natural fibers, synthetic fibers, or combinations thereof. Several suitable examples are disclosed in U.S. Patents 4,950,264, 4,988,344, 4,988,345, 3,978,185, 7,785,690, 7,838,099, 5,792,404, and 5,665,452.

[0029] In some examples, the top sheet may include tufts, as described in U.S. Patents 8,728,049, 7,553,532, 7,172,801, 8,440,286, 7,648,752, and 7,410,683. The top sheet may have a pattern of individual hair-like fibrils, as described in U.S. Patent 7,655,176 or 7,402,723. Additional examples of preferred top sheet materials are described in U.S. Patents 8,614,365, 8,704,036, 6,025,535, and U.S. Patent Application Publication 2015 / 041640. Another preferred top sheet may be formed from a three-dimensional substrate, as detailed in U.S. Patent Application Publication 2017 / 0258647. The top sheet may have one or more layers as described in U.S. Patent Application Publication No. 2016 / 0167334, U.S. Patent Application Publication No. 2016 / 0166443, and U.S. Patent Application Publication No. 2017 / 0258651.

[0030] As discussed herein, the component nonwoven web material from which the top sheet 20 is cut may be a nonwoven web material comprising, or primarily (by weight), fibers spun from polymer resins such as polyolefins and / or polyester, including but not limited to polypropylene, polyethylene, and their variants, blends, and two-component or multi-component arrangements.

[0031] Nonwoven webs can be formed by any preferred process that can distribute and accumulate spun fibers of varying lengths in a controlled manner on a moving forming belt to form a vat with a desired fiber distribution to a desired basis weight. Preferred processes include spunbonding and meltblowing. After accumulation, the vat can be processed to compact and bond the fibers into a cohesive web by any preferred method, including calendering, calendering thermal bonding, calendering compression bonding, and through-air bonding. The compacted web can be subjected to further processes such as water flow reinforcement or water flow entanglement to increase the z-direction entanglement of the fibers and increase loft.

[0032] In some examples, nonwoven web materials may be formed by a co-formation process in which finite-length hydrophilic fibers (e.g., plant-based fibers such as cotton or rayon fibers) are physically blended or mixed with a stream of longer but variable-length spun fibers spun from a polymer resin and arranged on a forming belt to form a web, e.g., U.S. Patent No. 8,017,534, U.S. Patent No. 4,100,324, U.S. Patent Application Publication No. 2003 / 020. This is described in Patent No. 0991, U.S. Patent No. 5,508,102, U.S. Patent Publication No. 2003 / 0211802, European Patent No. 0333228, International Publication No. 2009 / 10938, U.S. Patent Publication No. 2017 / 0000695, U.S. Patent Publication No. 2017 / 0002486, U.S. Patent No. 9,944,047, U.S. Patent Publication No. 2017 / 0022643, and U.S. Patent Publication No. 2018 / 0002848.

[0033] If no enhancements are made to the materials and / or processes used, single-component fibers spun from polymer resins generally tend to have a relatively simple surface shape, typically a circular or roughly elliptical cross-section, and a structure that is substantially uncurled or uncrimped along its length. As a result, when the spun fibers are deposited and accumulated on a forming belt, calendered, and bonded (e.g., in spunbonding), the resulting nonwoven web product will have a relatively lower loft and a relatively flat appearance compared to a web of equivalent basis weight formed from more complex shapes, such as curled or crimped fibers. Nonwoven webs with lower loft may be perceived by some consumers as having a less pleasant feel and appearance; that is, they may be perceived as being relatively less soft and less luxurious than those with higher loft.

[0034] To add loft to the web and increase its opacity without increasing the basis weight (and material usage), the fibers used to form the web can be spun in a multi-component, for example, two-component fiber configuration. The polymer resin can be selected and the polymer resin configured in the resin processing apparatus and spinneret beam to spin two-component fibers that crimp or curl as they leave the spinneret as a molten polymer stream, and then cool to solidify into fibers. Known processes and polymer resin selections can be used to produce curled spun two-component fibers having side-by-side, eccentric core-sheath, or other non-coaxial polymer component cross-sectional configurations. In such non-coaxial configurations, one of the polymer components can be selected and / or formulated to have a different melting temperature and / or cooling shrinkage rate than the other polymer components. As the fibers cool, the different properties of the polymer components in the component cross-sections of the molten fiber stream and the non-coaxial cross-sectional arrangement cause the fibers to cool and shrink at different rates, imparting curl to the fibers upon solidification. Each polymer resin component may be a different polymer, a different form or variant of the same polymer, or a different blend thereof. A more detailed disclosure of spinning curled or crimped binary fibers to form a nonwoven web can be found, for example, in U.S. Patent No. 8,501,646, U.S.-European Patent No. 1988793, and U.S. Patent Application Publication No. 2007 / 0275622. In some examples, the binary fiber may have each of the two components being primarily polypropylene-based resin components, formulated to impart different melting temperatures to each component. In some examples, the binary fiber may have each component being primarily polypropylene-based and the other primarily polyethylene-based. In some more specific examples, two-component fibers may be spun in an eccentric core-sheath configuration where the core component is primarily polypropylene-based and the sheath component is primarily polyethylene-based, with the polypropylene-based component being desirable for its greater tensile strength, and the polyethylene-based component being desirable for a smoother, more sleek surface feel, which helps to impart a silky feel to the fiber and nonwoven web materials.It will be understood that other combinations of polyolefins and / or other spun thermoplastic resins can be selected for their different cooling shrinkage rates, as well as other different qualities that affect the quality (including curl or crimp) and properties of the spun fibers in different ways.

[0035] The top sheet may further incorporate or include any features of the top sheet described in U.S. Patent Application No. 16 / 789,516 and / or No. 16 / 789,522.

[0036] Many commercially practical thermoplastic resins, which are sometimes desirable for processing and spinning into two-component fibers, are typically hydrophobic. Examples of such resins include polyolefins such as polypropylene and polyethylene. Nonwoven web materials formed from such fibers are also hydrophobic and therefore cannot readily accept or absorb aqueous fluids such as menstrual fluid. Therefore, when using such resins, additional measures can be taken to make the fibers and / or nonwoven webs hydrophilic. In some configurations, a suitable surfactant can be applied after the formation of the nonwoven web. A particularly suitable surfactant finishing agent is SILASTOL PHP 26 from Schill+Seilacher GmbH in Böblingen, Germany. The finishing can be applied to the web using any preferred method, for example, by a Kissroll coater. The finishing may be applied in an amount suitable for imparting the desired level of hydrophilicity to the nonwoven web, thereby helping to impart the desired level of capillary absorption / desorption pressure to the web. In some configurations, the finishing coating of SILASTOL PHP26 can be applied in an amount sufficient to constitute 0.30 to 0.60 percent, more preferably 0.40 to 0.50 percent, of the weight of the surfactant to the basis weight of the nonwoven web material after drying.

[0037] Wicking performance can be altered and controlled by the method of further processing the web. Factors such as the level of densification (i.e., high density) of the fiber mass in the end structure, and the orientation of individual fibers within the end structure, can affect absorbency and wicking performance.

[0038] Therefore, when the objectives intended herein are combined with the imparting of the preferred basis weight, density, and / or thickness discussed above, it may be desirable that nonwoven web materials, partially or almost entirely formed from fibers spun from thermoplastic polymer resins and used to produce topsheets, be formed via a nonwoven web manufacturing process in which a directional orientation, including some z-direction orientation, is imparted to a substantial portion of the fibers, rather than an orientation primarily biased along the mechanical direction or xy-plane of web structure formation. Following any preferred process of distributing and laying fibers onto bats on a horizontal forming belt (e.g., by a spunbond process), an additional process step may be employed to force some or some of the fibers to reorient in the z-direction. Preferred process steps may include needle punching and water-flow entanglement or water-flow strengthening. A fine, high-speed arrangement of water jets, directed towards the bat as it is carried over the jets, can be desirable because it is less likely to break fibers and less likely to form fibrous threads and surface fuzz (free fiber ends extending from the web surface), while also being effective in reorienting the length of the fibers. A vacuum water removal system (where air is drawn through the web in the z direction into a pattern of orifices or pores on a vacuum drum or belt that carries the bat, pulling the sprayed water along with the air) can be desirable because it tends to form, add, open, and / or open small z-directional passages within the web's fiber matrix, almost in an orifice or pore pattern. While not intended to be bound by theory, it is thought that z-oriented fiber portions and z-directional passages increase the web's ability and tendency to draw aqueous fluids in the z direction. In the top sheet, this means that the material can draw fluid downwards from the surface facing the wearer to the surface facing outwards, i.e., towards the absorbent layer below, thereby reducing the amount of fluid drawn up along the xy plane (and thus reducing the spread of stains from the discharged fluid in the lateral and / or vertical directions).

[0039] Absorption layer In some configurations, the absorbent layer 40 may be formed from or include layers of absorbent open-cell foam material. The foam material may include at least a first sublayer and a second sublayer 40a, 40b (Figure 3B) of absorbent open-cell foam material, and these sublayers are in direct contact with each other. In such examples, for the purposes described in more detail below, the sublayer facing the wearer may be made of a relatively larger foam material, and the sublayer facing outwards may be made of a relatively smaller-cell foam material.

[0040] The open-cell foam material may also be a foam material produced by polymerization of the continuous oil phase of a water-in-oil high internal phase emulsion (HIPE).

[0041] A water-in-oil HIPE has two phases. One phase is a continuous oil phase containing monomers to be polymerized and emulsifiers that help stabilize the HIPE. The oil phase may also contain one or more photoinitiators. The monomer components may be present in the oil phase in amounts of about 80% to about 99% by weight, and in certain examples, about 85% to about 95% by weight. Emulsifier components that are soluble in the oil phase and suitable for forming a stable water-in-oil emulsion may be present in the oil phase in amounts of about 1% to about 20% by weight. The emulsion may be formed at emulsification temperatures of about 20°C to about 130°C, and in certain examples, about 50°C to about 100°C.

[0042] Generally, monomers may be present in an amount of about 20% to about 97% by weight of the oil phase and may include at least one substantially water-insoluble monofunctional alkyl acrylate or alkyl methacrylate. For example, this type of monomer may include C4-C18 alkyl acrylates and C2-C18 methacrylates such as ethylhexyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, isodecyl acrylate, tetradecyl acrylate, benzyl acrylate, nonylphenyl acrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, isodecyl methacrylate, dodecyl methacrylate, tetradecyl methacrylate, and octadecyl methacrylate.

[0043] The oil phase may also contain approximately 2% to 40% by weight, and in certain cases approximately 10% to 30% by weight, of substantially water-insoluble polyfunctional crosslinked alkyl acrylates or methacrylates. The addition of these crosslinked comonomers or crosslinking agents imparts strength and elasticity to the resulting HIPE foam. Examples of this type of crosslinked monomer include monomers containing two or more activated acrylate, methacrylate groups, or combinations thereof. Non-limiting examples of these groups include 1,6-hexanediol diacrylate, 1,4-butanediol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, 1,12-dodecyl dimethacrylate, 1,14-tetradecanediol dimethacrylate, ethylene glycol dimethacrylate, neopentyl glycol diacrylate (2,2-dimethylpropanediol diacrylate), hexanediol acrylate methacrylate, glucose pentaacrylate, sorbitan pentaacrylate, and the like. Other examples of crosslinking agents include mixtures of acrylate and methacrylate moieties, such as ethylene glycol acrylate-methacrylate and neopentyl glycol acrylate-methacrylate. The ratio of methacrylate to acrylate groups in the mixed crosslinking agent may vary from 50:50 to any other ratio as needed.

[0044] The properties of the HIPE foam can be modified by adding any third substantially water-insoluble comonomer to the oil phase in a weight percentage of about 0% to about 15% by weight, and in certain cases, about 2% to about 8% by weight. In certain cases, "toughening" monomers that impart toughness to the resulting HIPE foam may be desired. These monomers include styrene, vinyl chloride, vinylidene chloride, isoprene, and chloroprene. While not limited to theory, such monomers are thought to help stabilize HIPE during polymerization (also known as "curing"), resulting in a more homogeneous and better formed HIPE foam with superior toughness, tensile strength, abrasion resistance, etc. Monomers can also be added to impart flame retardancy, for example, as disclosed in U.S. Patent No. 6,160,028. Monomers can be added to impart color (e.g., vinylferrocene), fluorescence properties, radiation resistance, opacity to radiation (e.g., lead tetraacrylate), charge dispersion, reflection of incident infrared light, absorption of radio waves, wetting of the surface of HIPE foam struts or bubble walls, or any other desired properties in HIPE foam. In some cases, these additional monomers may slow down the overall conversion process of HIPE to HIPE foam, but this trade-off is necessary if the desired properties must be imparted. Thus, such monomers can also be used to slow down the polymerization rate of HIPE. Examples of this type of monomer include styrene and vinyl chloride.

[0045] The oil phase may further contain emulsifiers to stabilize HIPE. Emulsifiers used in HIPE include (a) sorbitan monoesters of branched-chain C16-C24 fatty acids; linear-chain unsaturated C16-C22 fatty acids; and linear-chain saturated C12-C14 fatty acids, such as sorbitan monooleate, sorbitan monomyristate, and sorbitan monoesters, sorbitan monolaurate diglycerol monooleate (DGMO), polyglycerol monoisostearate (PGMIS), and polyglycerol monomyristate (polyglycerol (b) monomyristate (PGMM); (b) polyglycerol monoesters of branched C16-C24 fatty acids, linear unsaturated C16-C22 fatty acids, or linear saturated C12-C14 fatty acids, e.g., diglycerol monooleates (e.g., diglycerol monoesters of C18:1 fatty acids), diglycerol monomyristate, diglycerol monoisostearate, and diglycerol monoesters; (c) diglycerol monoaliphatic ethers of branched C16-C24 alcohols, linear unsaturated C16-C22 alcohols, and linear saturated C12-C14 alcohols, as well as mixtures of these emulsifiers. See U.S. Patent Nos. 5,287,207 and 5,500,451. Another emulsifier that can be used is polyglycerol succinate (PGS), formed from alkyl succinate, glycerol, and triglycerol.

[0046] Such emulsifiers, and combinations thereof, may be added to the oil phase in such a manner that they constitute about 1% to 20% by weight of the oil phase, about 2% to 15% by weight in certain examples, and about 3% to 12% by weight in certain other examples. In some configurations, co-emulsifiers may also be used to further control bubble size, bubble size distribution, and emulsion stability, for example, at high temperatures above about 65°C. Examples of coemulsifiers include phosphatidylcholine and phosphatidylcholine-containing compositions, aliphatic betaine, long-chain C12-C22 divalent aliphatic quaternary ammonium salts, short-chain C1-C4 divalent aliphatic quaternary ammonium salts, long-chain C12-C22 dialcoyl(alkenoyl)-2-hydroxyethyl, short-chain C1-C4 divalent aliphatic quaternary ammonium salts, long-chain C12-C22 divalent aliphatic imidazolinium quaternary ammonium salts, short-chain C1-C4 divalent aliphatic imidazolinium quaternary ammonium salts, long-chain C12-C22 monovalent aliphatic benzyl quaternary ammonium salts, long-chain C12-C22 dialcoyl(alkenoyl)-2-aminoethyl, short-chain C1-C4 monovalent aliphatic benzyl quaternary ammonium salts, and short-chain C1-C4 monohydroxyaliphatic quaternary ammonium salts. In some formulations, ditalodimethylammonium methyl sulfate (DTDMAMS) can be used as a coemulsifier.

[0047] The photoinitiator may be present in an amount ranging from approximately 0.05% to approximately 10% by weight of the oil phase, and in some configurations, in an amount ranging from approximately 0.2% to approximately 10%. A low amount of photoinitiator allows light to penetrate well into the HIPE foam, enabling polymerization to occur at depths greater than the HIPE foam. However, when polymerization is carried out in an oxygen-containing environment, it may be desirable to have a sufficient amount of photoinitiator to initiate polymerization and overcome oxygen inhibition. Photoinitiators can respond quickly and efficiently to a light source, with the generation of radicals, cations, and other types that can initiate polymerization reactions. Photoinitiators selected for use in foam formation within the scope intended by this disclosure can absorb ultraviolet light with wavelengths ranging from approximately 200 nanometers (nm) to approximately 800 nm, and in certain examples, from approximately 250 nm to approximately 450 nm. When the photoinitiator is present in the oil phase, suitable types of oil-soluble photoinitiators include benzyl ketal, α-hydroxyalkylphenone, α-aminoalkylphenone, and acylphosphine oxide.Non-limiting examples of suitable photoinitiators include: a combination of 2,4,6-[trimethylbenzoyldiphosphine]oxide and 2-hydroxy-2-methyl-1-phenylpropan-1-one (a 50:50 mixture of the two is sold as DAROCUR 4265 by Ciba Specialty Chemicals in Ludwigshafen, Germany); benzyldimethyl ketal (sold as IRGACURE 651 by Ciba Geigy); α-,α-dimethoxy-α-hydroxyacetophenone (sold as DAROCUR 1173 by Ciba Speciality Chemicals); 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one (sold as IRGACURE 907 by Ciba Speciality Chemicals); and 1-hydroxycyclohexyl-phenyl ketone (Ciba Specialty Examples include: sold by Chemicals as IRGACURE184; bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (sold by Ciba Speciality Chemicals as IRGACURE819); diethoxyacetophenone and 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-methylpropyl)ketone (sold by Ciba Speciality Chemicals as IRGACURE2959); and oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone] (sold by Lamberti spa (Gallarate, Italy) as ESACURE KIP EM).

[0048] The dispersed aqueous phase of HIPE contains water and may also contain one or more components such as initiators, photoinitiators, or electrolytes, and in certain examples, these one or more components are at least partially water-soluble.

[0049] One component in the aqueous phase may be a water-soluble electrolyte. The aqueous phase may contain about 0.2% to about 40% by weight, and in certain examples, about 2% to about 20% by weight, of water-soluble electrolytes. The electrolyte minimizes the tendency of mainly oil-soluble monomers, comonomers, and crosslinking agents to dissolve in the aqueous phase. Examples of electrolytes include chlorides and sulfates of alkaline earth metals such as calcium and magnesium, and chlorides and sulfates of alkali metals such as sodium. Such electrolytes may include buffers for controlling pH during polymerization, including inorganic counterions such as phosphates, borates, and carbonates, and mixtures thereof. Water-soluble monomers may also be used in the aqueous phase, examples of which are acrylic acid and vinyl acetate.

[0050] Another component that may be present in the aqueous phase is a water-soluble free radical initiator. The initiator may be present in an amount of about 20 mole percent or less based on the total moles of polymerizable monomers present in the oil phase. In certain examples, the initiator may be present in the oil phase in an amount of about 0.001 to about 10 mole percent based on the total moles of polymerizable monomers. Suitable initiators may include ammonium persulfate, sodium persulfate, potassium persulfate, 2,2'-azobis(N,N'-dimethylene isobutylamidine) dihydrochloride, azo initiators, redox pairs such as persulfate-bisulfate, persulfate-ascorbic acid, and other suitable redox initiators. In some configurations, the addition of the initiator to the monomer phase may be performed near the end of the emulsification process or immediately thereafter to reduce the possibility of premature polymerization that could clog the emulsification system.

[0051] The photoinitiator contained in the aqueous phase may be at least partially water-soluble and may constitute about 0.05% to about 10% by weight of the oil phase, and in certain examples, about 0.2% to about 10% by weight. If the amount of photoinitiator is small, light can penetrate well into the HIPE foam and bring about polymerization at a depth greater than the HIPE foam. However, if polymerization is carried out in an oxygen-containing environment, there should be enough photoinitiator to initiate polymerization and overcome oxygen inhibition. The photoinitiator can respond quickly and efficiently to a light source, with the generation of radicals, cations, and other types that can initiate polymerization reactions. Photoinitiators for use in foam formation within the scope intended by this disclosure can absorb ultraviolet light with wavelengths of about 200 nanometers (nm) to about 800 nm, in certain examples, about 200 nm to about 350 nm, and in certain examples, about 350 nm to about 450 nm. When the photoinitiator is contained in the aqueous phase, suitable types of water-soluble photoinitiators include benzophenone, benzyl, and thioxanthone. Examples of photoinitiators include 2,2'-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride; 2,2'-azobis[2-(2-imidazolin-2-yl)propane]disulfate dehydrated product; 2,2'-azobis(1-imino-1-pyrrolidino-2-ethylpropane)dihydrochloride; 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide]; 2,2'-azobis(2-methylpropionamidine)dihydrochloride; 2,2'-dicarboxymethoxydibenzalacetone, 4,4'-dicarboxymethoxydibenzalacetone, 4,4'-dicarboxymethoxydibenzalcyclohexanone, 4-dimethylamino-4'-carboxymethoxydibenzalacetone; and 4,4'-disulfoxymethoxydibenzalacetone. Other suitable photoinitiators are described in U.S. Patent No. 4,824,765.

[0052] In addition to the components described above, other components may be included in either the aqueous or oil phase of HIPE. Examples include antioxidants, e.g., hindered phenols, hindered amines, and light stabilizers; plasticizers, e.g., dioctyl phthalate, dinonyl sebacate; flame retardants, e.g., halogenated hydrocarbons, phosphates, borates, and inorganic salts, e.g., antimony trioxide, ammonium phosphate, or magnesium hydroxide; dyes and pigments; fluorescent agents; filler particles, e.g., starch, titanium dioxide, carbon black, or calcium carbonate; fibers; chain transfer agents; odor absorbers, e.g., activated carbon microparticles; soluble polymers; soluble oligomers; and similar substances.

[0053] HIPE foams are produced from the polymerization of monomers containing a continuous oil phase of HIPE. In certain examples, a HIPE foam layer may have one or more sublayers and may be either a homogeneous or heterogeneous polymer open-cell foam. Homogeneity and heterogeneity relate to different layers within the same HIPE foam, which are similar in the case of a homogeneous HIPE foam and different in the case of a heterogeneous HIPE foam. A heterogeneous HIPE foam may contain at least two different sublayers that differ in chemical composition, physical properties, or both. For example, these sublayers may differ in one or more of the following: foam density, polymer composition, specific surface area, or pore size (also called bubble size). For example, in a HIPE foam that differs in pore size, the average pore size of each sublayer may differ by at least about 20%, at least about 35% in certain examples, and at least about 50% in other examples. In another example, if the difference in sublayers of a HIPE foam layer relates to density, the density of the layers may differ by at least about 20%, at least about 35% in certain examples, and at least about 50% in other examples. For example, if one layer of HIPE foam has a density of 0.020 g / cc, another layer may have a density of at least about 0.024 g / cc or less than 0.016 g / cc, at least about 0.027 g / cc or less than 0.013 g / cc in certain examples, and at least about 0.030 g / cc or less than 0.010 g / cc in other examples. If the difference between layers relates to the chemical composition of HIPE or HIPE foam, the difference may reflect a difference in the relative amount of at least one monomer component, for example, at least about 20%, at least about 35% in certain examples, and at least about 50% in further examples. For example, if one sublayer of HIPE or HIPE foam consists of about 10% styrene in its formulation, another sublayer of HIPE or HIPE foam may consist of at least about 12%, and in certain examples, at least about 15%.

[0054] A HIPE foam layer structured to have separate sublayers formed from different HIPE can provide a HIPE foam layer having a range of desired performance characteristics. For example, a HIPE foam layer comprising first and second foam sublayers, where the first foam sublayer has a relatively larger pore size or bubble size than the second foam sublayer, can absorb incoming fluid more quickly than the second sublayer when used in an absorbent article. For example, when using a HIPE foam layer to form the absorbent layer of a feminine hygiene pad, the first foam sublayer can be overlaid on a second foam sublayer having a relatively smaller pore size compared to the first foam sublayer. The smaller pore size exerts greater capillary pressure, drawing the acquired fluid from the first foam sublayer and restoring the first foam sublayer's ability to acquire more fluid from above. The pore size of the HIPE foam may be in the range of 1 to 200 μm, and in certain examples, may be less than 100 μm. The HIPE foam layer of this disclosure, having two main parallel surfaces, may have a thickness of about 0.5 to about 10 mm, and in certain examples, about 2 to about 10 mm. The desired thickness of the HIPE foam layer will depend on the material used to form the HIPE foam layer, the rate at which the HIPE is deposited on the belt, and the intended use of the resulting HIPE foam layer.

[0055] The HIPE foam layer of this disclosure is a relatively continuous cell. This refers to individual cells or pores in the HIPE foam layer that are in substantially unobstructed communication with adjacent cells. Cells in a HIPE foam structure that are thus substantially continuous have intracellular openings or windows of sufficient size to rapidly transfer fluid from one cell to another within the HIPE foam structure. For the purposes of this disclosure, a HIPE foam is considered "continuous" if at least about 80% of the cells in the HIPE foam, each at least 1 μm in size, are in fluid communication with at least one adjacent cell.

[0056] In addition to being open-cell, in certain examples, HIPE foams are adapted to be sufficiently hydrophilic to absorb aqueous fluids. In some examples, the inner surface of the HIPE foam may be made hydrophilic by residual hydrophilic surfactants or salts remaining in the HIPE foam after polymerization, by selected post-polymerization HIPE foam treatment procedures (described later), or a combination of both.

[0057] In some configurations, for example, when used to form the absorbent structure of a women's hygiene pad, the HIPE foam layer can be flexible and exhibit an appropriate glass transition temperature (Tg). Tg represents the midpoint of the transition between the glassy and rubbery states of the polymer. Generally, HIPE foams with a Tg higher than the operating temperature may have high strength, but they are also relatively rigid and potentially prone to fracturing (brittleness). In certain specific cases, regions of the HIPE foam of this disclosure that exhibit either a relatively high Tg or excessive brittleness will be discontinuous. These discontinuous regions also generally exhibit high strength, so they can be prepared at a low density without compromising the overall strength of the HIPE foam.

[0058] HIPE foams intended for applications requiring flexibility should include at least one continuous region having the lowest possible Tg, as long as the HIPE foam as a whole possesses acceptable strength at the operating temperature. In certain cases, the Tg of this region is less than approximately 40°C for foams used under approximately ambient temperature conditions, and in other specific cases, the Tg is less than approximately 30°C. With respect to HIPE foams used in applications where the operating temperature is higher or lower than the ambient temperature, the Tg of the continuous region may be up to 10°C higher than the operating temperature, may be the same as the operating temperature in certain cases, and may be about 10°C lower than the operating temperature in further cases where flexibility is desired. Therefore, monomers are selected to provide the corresponding polymer having the lowest possible Tg.

[0059] HIPE foams useful for forming absorbent layers and / or sublayers within the scope intended of this disclosure, and methods for producing them, are incorporated herein by reference to the extent not contrary to this disclosure, U.S. Patents 10,045,890, 9,056,412, 8,629,192, 8,257,787, 7,393,878, 6,551,295, and 6,525,10 U.S. Patent No. 6, U.S. Patent No. 6,550,960, U.S. Patent No. 6,406,648, U.S. Patent No. 6,376,565, U.S. Patent No. 6,372,953, U.S. Patent No. 6,369,121, U.S. Patent No. 6,365,642, U.S. Patent No. 6,207,724, U.S. Patent No. 6,204,298, U.S. Patent No. 6,158,144, U.S. Patent No. 6,107,538, U.S. Patent No. 6,107,356, U.S. Patent No. 6,083,211, U.S. Patent No. 6, U.S. Patent No. 013,589, U.S. Patent No. 5,899,893, U.S. Patent No. 5,873,869, U.S. Patent No. 5,863,958, U.S. Patent No. 5,849,805, U.S. Patent No. 5,827,909, U.S. Patent No. 5,827,253, U.S. Patent No. 5,817,704, U.S. Patent No. 5,817,081, U.S. Patent No. 5,795,921, U.S. Patent No. 5,741,581, U.S. Patent No. 5,652,194, U.S. Patent No. 5,650,222, U.S. Japanese Patent No. 5,632,737, US Patent No. 5,563,179, US Patent No. 5,550,167, US Patent No. 5,500,451, US Patent No. 5,387,207, US Patent No. 5,352,711, US Patent No. 5,397,316, US Patent No. 5,331,015, US Patent No. 5,292,777, US Patent No. 5,268,224, US Patent No. 5,260,345, US Patent No. 5,250,576, US Patent No. 5,149,Examples of foams and methods described in U.S. Patent No. 720, U.S. Patent No. 5,147,345, and U.S. Patent Publication Nos. 2005 / 0197414, 2005 / 0197415, 2011 / 0160326, 2011 / 0159135, 2011 / 0159206, 2011 / 0160321, and 2011 / 0160689 are also included, but are not limited to.

[0060] As shown in Figures 1 and 2, the absorbent layer formed of HIPE foam may include one or more patterns of forward and backward pores 42f, 42r, including at least a first pattern located within the expected discharge location near the intersection of the longitudinal axis 100 and the transverse axis 200 of the pad. The pores 42f, 42r may be formed by punching, cutting, molding, or otherwise extending throughout the entire Z-direction depth of the HIPE foam absorbent layer, or penetrating only the layer facing the wearer, or in part of the portion facing the wearer. When the HIPE foam absorbent layer is positioned in direct contact with the top sheet as described herein, and there is no intervening trapping layer formed of another material, the pores 42f, 42r can function as a group of “reservoirs” that help receive, temporarily hold, and distribute relatively small amounts of rapid menstrual fluid discharge until the HIPE foam has enough time to distribute and absorb the fluid by capillary action. In addition, such pores help to reduce the bending stiffness of the absorbent layer, which may help to increase the wearer’s comfort of the pad. For example, the area occupied by the bonding region 25 may include a pattern of holes having an average radius of 1.0 mm to 4.0 mm, more preferably 1.5 mm to 3.5 mm, or other maximum dimensions. The pattern may be 1 cm 2 3.0 to 9.0 holes per unit area, more preferably 1 cm 2The pores may be present with a numerical density of 4.0 to 8.0 pores per unit area. When selecting the appropriate average size, numerical density, and surface area occupied by the pore pattern, the manufacturer may wish to balance the volume of the desired “reservoir” when it is necessary to hold the absorbent material in close proximity to and near the expected discharge point. Further details regarding such pore configurations combined with examples of suitable absorbent layers can be found in U.S. Patent No. 8,211,078.

[0061] Preferably, the top sheet 20 is bonded to the wearer-facing surface of the absorbent layer 40 in a manner that ensures close proximity between the two, providing rapid fluid movement through the top sheet to the absorbent layer 40, while avoiding an unacceptable degree of obstruction that would hinder downward fluid movement (e.g., caused by excessively large deposits of adhesive between these components). Bonding the top sheet to the absorbent layer also helps to fix the absorbent layer 40 within the enclosed space, helping to integrate the overall structure of the pad and enhance the user / wearer's impression of quality. The top sheet 20 may be bonded to the absorbent layer 40 in any preferred manner, including that described in U.S. Patent Application No. 16 / 789,522. By effectively integrating the absorbent layer 40 and the top sheet 20, such bonding also helps to reduce the likelihood of the pad folding or creasing along a series of holes, thereby further directing and facilitating hinge or fold along the path of the macro-aperture, as intended herein. To further integrate the pad and minimize the occurrence of open spaces (spaces not occupied by absorbent material) between the top sheet and the back sheet, the surface facing outward of the absorbent layer may also be bonded to the back sheet, either the surface of the back sheet 30 facing the wearer or the surface of the absorbent layer 40 facing outward, via a deposition pattern or dispersion of adhesive applied between these components.

[0062] Macrovoid Referring to Figures 4A to 4D, the absorbent layer 40 may have an arrangement of macrovoids 51. As intended herein, the macrovoids 51 may have similarities to the holes 42f and 42r described above in that they are visible voids formed within the absorbent layer 40. However, they are distinguished for the purposes intended herein in that the macrovoids 51 function to facilitate or promote substantially longitudinal folding or folding of the absorbent layer 40. In contrast, the front holes 42f function as fluid reservoirs as described above, and the rear holes 42r function as fluid reservoirs or channels, and also facilitate or promote substantially lateral bending / curving of the pad upward around the wearer's buttocks at the rear. In some configurations, for the macrovoid 51 to function more reliably as described below, it may be desirable that the macrovoid 51 has an xy-plane aspect ratio of at least 1.5:1, more preferably at least 2:1, and that its longer dimensions be substantially oriented along paths such as paths 50f, 50r.

[0063] It has been found that providing the absorbent layer 40 with the arrangement of macrovoids having the characteristics described herein can dramatically improve the ability of the pad 10 to closely conform to the wearer's body in the groin area while remaining comfortable for the wearer.

[0064] A suitable arrangement may include a path of the macrovoid 51 comprising left and right forward paths 50f arranged substantially symmetrically on both sides of the vertical axis 100, and a backward path 50r substantially centered along the vertical axis 100 and / or substantially following the vertical axis 100. The left forward path section may be located primarily forward of the horizontal axis 200, starting at a left-center position close to the intersection of the horizontal axis 200 and the vertical axis 100, and ending at a left-outer position located forward of a first left-center position and further out of the vertical axis 100 than the first left-center position. The right forward path section may be located primarily forward of the horizontal axis 200, starting at a right-center position close to the intersection of the horizontal axis 200 and the vertical axis 100, starting at a right-center position located forward of a first right-center position and ending at a right-outer position further out of the vertical axis 100 than the first right-center position. The backward path section may be located primarily backward of the horizontal axis 200.

[0065] Each of the left and right front paths 50f may have a first endpoint 50fe1 located relatively closer to the longitudinal axis 100 of the pad and closer to the intersection of axes 100 and 200 (the “center” as used herein) than a second endpoint 50fe2. The rear path 50r may have a first endpoint 50re1 located relatively closer to the transverse axis 200 than a second endpoint 50re2. To maintain the structural integrity of the foam layer by avoiding an increased possibility of tear propagation across paths that may result from handling or movement of the foam layer during pad manufacturing, pad handling, or pad use / wear, it may be desirable that the left and right front paths 50f do not converge or intersect completely, for example, on or near the longitudinal axis 100. For similar reasons, it may be desirable that the front path 50f does not meet or intersect with the rear path 50r.

[0066] Referring particularly to Figures 4C to 4F, through prototyping and testing, it was found that the arrangement of macrovoids 51 having these features facilitates the folding or hinge of the absorbent layer 40 around paths 50f and 50r. This may be more easily achieved when the absorbent layer 40 is formed of a flexible foam such as polyurethane foam or HIPE foam as described herein. Through testing, it was found that when a pad having some or any combination of these features is properly positioned and applied to the user / wearer's underwear and then normally worn, zones 40fl and 40fr tend to bend upward (or toward the wearer's body) around the folds formed along the path 50f of the macrovoids 51, resulting in the pad taking on a cup-like configuration (in cross-section) that conforms better to the wearer's body in the area adjacent to the vagina. (See Figure 4E.) Simultaneously, zones 40rl and 40rr tend to flex downward (or away from the wearer's body) around folds formed along the path 50r of the macrovoid 51, causing the pad to adopt an inverted V-shape configuration (in lateral cross-section) that better conforms to the wearer's body along the groove of the buttocks. (See Figure 4F.) If the absorbent layer 40 is formed of a suitable foam such as polyurethane or HIPE foam, the flexibility and elasticity of the foam may allow the absorbent layer 40 to flex and migrate between these two configurations in the transition zone 40t more effectively.

[0067] Referring to Figures 4G and 4H, these conformability tendencies can be synergistically enhanced by including and combining patterns of holes 42f and 42r, as described above. For example, a preferred pattern of aperture 42f, such as the pattern shown in Figures 4G and 4H, which is mainly or entirely located between the left and right anterior paths 50f, can not only perform the reservoir and distribution functions described above, but can also increase the flexibility and pliability of the absorbent layer 40 within its zone, enhancing its ability to cup around the user / wearer's body in the area adjacent to the vagina.

[0068] The appropriate pattern of aperture 42r, in cooperation with the macrovoids 51 in the rear portion of the absorbent layer 40, allows the rear portion of layer 40 to curve upward and wrap around the wearer's buttocks when viewed from the side, while simultaneously creating folds along the longitudinal axis 100 to better conform to the wearer's body in and near the buttock groove. It will be understood that attempts to conform generally flat / planar materials to such complexly curved intersecting surfaces can otherwise be difficult.

[0069] In some configurations, it may be preferable for the path of macrovoids 51 to traverse or encompass more than two, more preferably more than three, even more preferably more than four, and even more preferably more than five macrovoids 51, with regions of continuity of the absorbent layer material between the macrovoids. In some configurations, it may be preferable for the path of macrovoids 51 to traverse or encompass about 2 to about 18 macrovoids, or about 4 to about 15 macrovoids 51, or about 6 to about 12 macrovoids 51, or about 8 to about 10 macrovoids 51, with regions of continuity of the absorbent layer material between the macrovoids 51. Providing regions of material continuity between consecutive macrovoids 51 along the path reduces or prevents the ability of the macrovoids to carry fluid along it (which may have undesirable consequences), and also helps the absorbent layer maintain structural robustness and avoid its undesirable tearing, while still facilitating the desired folds along the path. In some configurations, the region of material continuity between consecutive macrovoids 51 along the path may have a gap length (G) of approximately 2 mm to 6 mm, or approximately 3 mm to 5 mm.

[0070] When the pores 42r, which are generally oriented laterally, are included together with the paths 50r of the macrovoids 51 (as described herein), it may be desirable that the macrovoids 51 and the laterally oriented pores 42r do not intersect or coincide, i.e., that regions of material continuity exist between the macrovoids 51 and the pores 42r, for the purpose of maintaining the structural robustness of the absorption layer 40.

[0071] As shown in Figure 4H, in some configurations it may be preferable to have one or more left and / or right front paths 50f of the macrovoid. For example, a suitable arrangement may include a first left front path 50fl1 and a second left front path 50fl2, and / or a first right front path 50fr1 and a second right front path 50fr2. In some configurations, the distance (D1) between the first left front path 50fl1 and the second left front path 50fl2, and / or between the first right front path 50fr1 and the second right front path 50fr2, may be about 2 mm to about 6 mm, or about 3 mm to about 4 mm.

[0072] In some configurations, the macrovoids of the first left front path 50fl1 and the second left front path 50fl2 may be staggered. In some configurations, the macrovoids of the first right front path 50fr1 and the second right front path 50fr2 may be staggered. The first left front path 50fl1 and the second left front path 50fl2, and / or the first right front path 50fr1 and the second right front path 50fr2 may be substantially the same length or of different lengths. In some configurations, the second left front path 50fl2 may contain more macrovoids than the first left front path 50fl1 and / or be longer than the first right front path 50fr1, or vice versa. In some configurations, the second right front path 50fr2 may contain more macrovoids than the first right front path 50fr1 and / or be longer than the first right front path 50fr1, or vice versa.

[0073] Referring to Figures 5, 11A, and 11B, it may be desirable for the macrovoids along the path to have a width mvw of 20% to 300%, preferably 50% to 150%, and more preferably 75% to 125%, of the thickness clpr of the absorbent layer 40. Limiting the macrovoid width to values ​​within these ranges can help ensure that the desired level of flexibility is provided to facilitate easy folding or creasing along the path of the macrovoid, while avoiding macrovoids of a size that would be a gapping opening through the absorbent layer, allowing menstrual blood to move through the absorbent layer in an uncontrolled manner into the space between the absorbent layer 40 and the backsheet 30. Once the topsheet 20 is bonded to the absorbent layer 40 as described above, its portion 20m that bridges the macrovoids suppresses the separation of the absorbent layer 40 across the macrovoids 51 as it bends around the path of the macrovoids (as can be understood by comparing Figures 11A and 11B). This pulls together portions of the absorbent layer 40 inside the fold or crease (as shown in Figure 11B), preferably closing the opening or gap in the absorbent layer provided by the macrovoid 51. The portion 30m of the backsheet 30 bridging the macrovoid 51 may buckle to accommodate the fold or crease, for example, in the manner shown in Figure 11B. If bending / folding / creasing is performed in the opposite direction to that shown in Figure 11B, the roles of the topsheet and backsheet are reversed, and the gap in the absorbent layer in the macrovoid is closed at the top rather than the bottom, as shown in Figure 11B. (For the purposes of this specification, the width of the macrovoid is its maximum dimension in the plane of the surface of the absorbent layer facing the wearer, along the direction perpendicular to the path, at any point where the path traverses it. See, for example, the dimension mvw shown in Figures 5 and 7. The absorbent layer thickness clpr is measured using the thickness measurement method provided below.)

[0074] In other examples, for similar purposes, the macrovoid 51 may be formed or imparted to the absorption layer such that it does not extend in the z-direction through the entire z-direction depth / thickness of the absorption layer 40, but rather extends only partway through the absorption layer 40. See the example shown in Figure 12.

[0075] The macrovoid 51 may have a length of approximately 2 mm to 10 mm, or approximately 2.5 mm to 8 mm, or approximately 3 mm to 6 mm. In some configurations, it may be preferable to have macrovoid 51 with a length of approximately 2 mm to 6 mm. Although not limited to theory, macrovoids with a length of less than approximately 6 mm may help minimize tearing during high-speed machining.

[0076] A particularly suitable configuration may include a macrovoid 51 in the forward path 50f having a length of approximately 4 mm and a gap length (G) between macrovoids of approximately 3 mm.

[0077] A particularly preferred configuration includes a macrovoid 51 with a rear path 50r having a length of approximately 3 mm, and the gap length (G) between the macrovoids and / or between the macrovoids and the holes 42r intersecting the macrovoid paths may be approximately 3 mm.

[0078] In some configurations, the ratio of the macrovoid length to the void length of the macrovoid 51 path can be approximately 30:1 to approximately 1:5, or approximately 10:1 to approximately 1:1.

[0079] Macrovoids 51 (and, if included, associated holes 42f, 42r) may be formed within or imparted to the absorbent layer 40 by any preferred method or process. In some configurations, they may be mechanically knife-cut, die-cut, or perforated through the absorbent layer or its precursor web or sheet. In some configurations, the process may involve passing the layer (or precursor material of the web or sheet) through a nip between a pair of die-cut rollers configured to cut a desired arrangement of macrovoids (and, if included, holes) through the layer, web, or sheet. In some examples, the same die-cut rolls may be configured to cut out both holes 42f, 42r and macrovoids 51. In such examples, the peripheral edges and inner walls of the resulting macrovoids (and, if included, holes) have visible evidence of such mechanical cutting. In other examples, the material may be removed from the absorption layer (or precursor material in web or sheet form) by other methods configured to remove the material along a defined profile that forms a desired macrovoid shape, including but not limited to laser cutting, fluid or water jet cutting, or etching. In other configurations, the material for forming the absorption layer may be formed in or on a mold configured to form a desired arrangement of macrovoids 51 with or without holes 42f and / or 42r into the absorption layer (or precursor material). However, mechanical cutting or punching, or fluid jet cutting or etching may be preferred because these methods leave open, exposed bubbles or holes in the absorption layer material along the peripheral edges / walls of the macrovoids (and holes, if included), which can enhance fluid distribution and absorbency.

[0080] Referring to Figure 4I, in some configurations it may be desirable to add a reinforcing material 60 molded beneath the absorbent layer 40 (i.e., on the side facing outward from the absorbent layer 40). The reinforcing material 60 may be a sublayer component molded and adapted to impart increased bending resistance to one or more selected areas of the pad occupied by the absorbent layer 40, and in cooperation with the path of the macrovoid 51, to direct and / or more effectively guide hinges and folds or creases along it, thereby reducing or avoiding folds / creases of the pad at undesirable locations. Thus, in configurations including the reinforcing material 60, it may be desirable that the reinforcing material 60 be located beneath one or more areas of the absorbent layer 40 not occupied by the macrovoid 51. In the example shown in Figure 4I, the reinforcing material 60 is located beneath the area between the left and right paths of the macrovoid 51, mainly in the forward area of ​​the pad (i.e., mainly forward of the transverse axis 200), straddling the longitudinal axis 100 and substantially symmetrical with respect to it. This feature allows the absorbent layer 40 to be folded more easily along the left and right paths of the indicated macrovoid 51 as intended, but also resists excessive bending or folding in undesirable locations, such as intermediate regions between the left and right paths. This may be desirable in configurations that include a pattern of aperture 42f (e.g., as shown in Figures 4G and 4H) between the left and right paths of the macrovoid 51, otherwise it may reduce the stiffness of the absorbent layer 40 in that region. Reinforcement 60 may be added so as to be below part or all of the pattern of aperture 42f.

[0081] The reinforcing material 60 may be formed from, or include, additional molded sections of nonwoven web material, film, tissue, paper, or any other additional material that impart additional bending stiffness to selected and defined areas of the pad occupied by the absorbent layer 40. In some configurations, the reinforcing material 60 may simply be formed or imparted by an added or extra-basis deposit between the absorbent layer 40 and the backsheet 30, having a defined shape configured to impart stiffness to the corresponding defined areas of the pad. In other configurations, the reinforcing material 60 may be formed from, or include, an application of additional or increased basis weight fastening adhesive 35 applied to the outward-facing surface of the backsheet in areas where additional reinforcement is desired, as described above. In such configurations, when the user places and fastens the pad to their underwear for use / wear, the desired additional stiffness is brought about by the increased and / or relatively more continuous contact surface area and the bonding / adhesion of the pad structure to the underwear fabric in areas of the desired additional stiffness along that contact surface area.

[0082] In other configurations, one or more portions or regions of the pad occupied by the absorbent layer 40 may undergo selective mechanical deformation via deformation rollers to increase the flexibility / flexibility of the absorbent layer 40, and thus increase the flexibility / flexibility of the pad in selected zones, as described in U.S. Patent Application No. 63 / 424,979. Referring to Figure 4D, in some configurations, the transition zone 40t may undergo such selective deformation to increase its ability to flex and transition from a creased / cupping configuration reflected in Figure 4E to a creased / inverted "V" configuration reflected in Figure 4F. In other configurations, one or more peripheral edge regions of the absorbent layer 40 may be selectively deformed to increase the flexibility and flexibility of the absorbent layer 40 around regions adjacent to or adjacent to its xy-plane peripheral edge 41. In some configurations, a portion or preferably a large portion of the xy-plane surface area of ​​the pad, including the surface area of ​​the absorbent layer 40 located behind the transverse axis 200, may be mechanically deformed as described above. This can improve the pad's ability to conform to and move with the user / wearer's body along the contour of the gap in the buttocks. Additionally or alternatively, in some configurations, a portion, or preferably a large portion, of the pad's xy-plane surface area, including the surface area of ​​the absorbent layer 40 positioned laterally outward of the left and right anterior path sections 50f, can be mechanically deformed as described above. This can improve the pad's ability to conform to and move with the user / wearer's body in the slitted anterior portion of the groin area where the section contacts the lower torso, i.e., the portion where the section contacts the lower body. However, in such configurations, it may be desirable to avoid mechanical deformation of portions of the absorbent layer (40) including the paths of the macrovoids 50f, 50r, or the macrovoids 51 themselves, in order to avoid undesirable damage to the pad structure. When the pad is mechanically deformed, the foam layer has visible evidence of such deformation in the area subjected to such deformation, in the form of a tear or crack along the z direction, as described in U.S. Patent Application No. 63 / 424,979.

[0083] Back seat The backsheet 30 can be positioned adjacent to the surface facing outward of the absorption layer 40 and can be bonded to this surface by any preferred mounting method. For example, the backsheet 30 may be fixed to the absorption layer 40 by a uniform continuous layer of adhesive, a patterned layer of adhesive, or an arrangement of independent lines, spirals, or dots of adhesive. Alternatively, mounting methods may include thermal bonding, pressure bonding, ultrasonic bonding, dynamic mechanical bonding, or any other preferred mounting mechanism, or a combination thereof. In other configurations, it is intended that the absorption layer 40 is not directly bonded to the backsheet 30.

[0084] The backsheet 30 may be impermeable to or substantially impermeable to liquids (e.g., urine, menstrual fluid) and may be manufactured from a thin plastic film, but other flexible liquid-impermeable materials may also be used. As used herein, the term “flexible” refers to a material that conforms easily to the overall shape and contours of the human body. The backsheet 30 can prevent, or at least substantially prevent, the fluid absorbed and contained within the absorbent layer 40 from escaping from and reaching articles of the wearer’s clothing, such as underwear and other clothing, that may come into contact with the pad 10. However, in some examples, the backsheet 30 may be made to allow vapor to escape from the absorbent layer 40 (i.e., the backsheet is made to be breathable), while in other examples, the backsheet 30 may be made not to allow vapor to escape (i.e., it is made to be non-breathable). Thus, the backsheet 30 may include a polymer film, such as a polyethylene or polypropylene thermoplastic film. Suitable materials for the backsheet 30 are, for example, thermoplastic films having a thickness of about 0.012 mm (0.5 mil) to about 0.051 mm (2.0 mil). Any suitable backsheet known in the art may be used in conjunction with the present invention.

[0085] Some preferred examples of backsheets are described in U.S. Patent Nos. 5,885,265, 4,342,314, and 4,463,045. Suitable single-layer breathable backsheets for use herein include, for example, those described in British Patent Nos. A2184389, A2184390, A2184391, U.S. Patent Nos. 4,591,523, 3,989,867, 3,156,242, International Publication No. 97 / 24097, U.S. Patent Nos. 6,623,464, 6,664,439, and 6,436,508.

[0086] The backsheet may have two layers, namely a first layer comprising a vapor-permeable aperture-forming film layer and a second layer comprising a breathable microporous film layer, as described in U.S. Patent No. 6,462,251. Other suitable examples of two-layer or multi-layer breathable backsheets for use herein include those described in U.S. Patents No. 3,881,489, 4,341,216, 4,713,068, and 4,818,600; and European Patents No. 203821, 710471, 710472, and 0793952.

[0087] Thickness measurement The thickness of the absorbent layer 40 test specimen is measured as the distance between the reference platform on which the specimen is placed and the press that applies a specified pressure to the specimen over a specified period of time. All measurements are performed in a laboratory maintained at 23°C ± 2°C and 50% ± 2% relative humidity, and the test specimen is conditioned in this environment for at least two hours prior to testing.

[0088] The thickness is measured using a manual micrometer equipped with a clamp capable of applying a steady pressure of 2.0 kPa ± 0.01 kPa to the test specimen. The manual micrometer is a self-weight instrument with accurate readings to 0.001 mm. A suitable instrument is the Mitutoyo Series 543 ID-C Digimatic, available from VWR International, or an equivalent. The clamp is a flat, grounded, circular movable surface with a diameter smaller than the test specimen and capable of applying the required pressure. A suitable clamp has a diameter of 25.4 mm, but a smaller or larger clamp can be used depending on the size of the specimen being measured. The test specimen is supported by a horizontal, flat reference platform that is larger than the surface of the clamp and parallel to the surface of the clamp. The system is calibrated and operated according to the manufacturer's instructions.

[0089] If necessary, test samples are obtained by removing them from the absorbent material. When removing test samples from the absorbent material, care should be taken not to impart any contamination or dimensional deformation to the test samples. Test samples must be obtained from an area free of folds or wrinkles and must be larger than the presser foot.

[0090] To measure the thickness, first zero the micrometer against a horizontal, flat reference platform. Place the test specimen on the platform with the test position centered under the clamp. Gently lower the clamp at a rate of 3.0 mm ± 1.0 mm / second until the full pressure is applied to the test specimen. After waiting 5 seconds, record the thickness of the test specimen in 0.01 mm increments. Repeat the same process for a total of five duplicate test specimens. Calculate the arithmetic mean of all thickness measurements and report it in 0.01 mm increments. [Examples]

[0091] In consideration of the foregoing disclosure, the following embodiments are intended herein.

[0092] 1. A liquid-permeable top sheet (20), a liquid-impermeable back sheet (30), an absorbent layer (40) wrapped between the top sheet and the back sheet, a front end, a rear end, a vertical axis (100) and a horizontal axis (200), the vertical axis (100) and the horizontal axis (200) having an intersection point, The absorption layer (40) includes a layer of open-cell foam having a thickness in the z direction and an outer circumference (41) along the xy plane, the foam layer having arrangements of macrovoids (51) therein, the macrovoids having depth in the z direction, and the arrangement of the macrovoids defines paths (50f, 50r) located along the xy plane of the foam layer. A left-forward path section (50f) is located primarily in front of the horizontal axis, starting at a left-center position close to the axis intersection, and ending at a left-outer position located in front of the first left-center position and further outward on the vertical axis than the first left-center position. A women's hygiene pad comprising: a right-front path section (50f) located primarily in front of the horizontal axis, starting at a right-center position close to the axis intersection, and ending at a right-outer position located in front of the first right-center position and further outward on the vertical axis than the first right-center position.

[0093] 2. The feminine hygiene pad according to Example 1, wherein the arrangement of macrovoids further includes a rear path section (50r) substantially along the longitudinal axis and mainly located behind the transverse axis.

[0094] 3. The feminine hygiene pad according to Example 2, wherein one or more, preferably most, more preferably all, of the macrovoids traversed by the rear path section (50r) do not intersect or coincide with any of the existing rear elongated holes (42r), and these rear elongated holes (42r) have their longest dimension oriented mainly along the lateral direction.

[0095] 4. A feminine hygiene pad according to any one of Examples 1 to 3, wherein the absorbent layer has an arrangement of one or more posterior elongated holes (42r) located along the xy plane of the pad and mainly posterior to the transverse axis, the longest dimension thereof being oriented mainly along the transverse direction.

[0096] 5. A women's hygiene pad according to any one of Examples 1 to 4, wherein the absorbent layer has an arrangement of one or more front holes (42f) located along the xy plane of the pad, mainly between the left front pathway section and the right front pathway section.

[0097] 6. A feminine hygiene pad according to any one of Examples 1 to 5, wherein at least a portion, preferably most, of the z-direction depth of the macrovoids extends entirely through the thickness of the foam layer.

[0098] 7. A women's hygiene pad according to any one of Examples 1 to 4, wherein at least a portion, preferably most, of the z-direction depth of the macrovoids extends only partially through the thickness of the foam layer, preferably the z-direction depth is 40% to 70% of the thickness of the foam layer, and preferably the z-direction depth starts from the wearer-facing side of the foam layer and extends therefrom.

[0099] 8. A feminine hygiene pad according to any one of Examples 1 to 7, wherein one or more of the pathway sections traverse at least four, preferably at least five, macrovoids.

[0100] 9. A feminine hygiene pad according to any one of Examples 1 to 8, wherein each macrovoid along each path section has a width equal to 20% to 200%, more preferably 50% to 150%, and even more preferably 75% to 125% of the thickness in the z direction.

[0101] 10. A women's hygiene pad according to any one of Examples 1 to 9, wherein the open-cell foam is one or more of HIPE foam and polyurethane foam, preferably HIPE foam.

[0102] 11. A women's hygiene pad according to any one of Examples 1 to 10, wherein the peripheral portion tapers from a wider xy dimension laterally at the rear of the pad to a narrower xy dimension laterally at the front of the pad.

[0103] 12. A feminine hygiene pad according to any one of Examples 1 to 11, comprising a reinforcing material (60) located beneath one or more portions of the absorbent layer.

[0104] 13. The feminine hygiene pad described in Example 12, wherein the reinforcing material is not located beneath the majority of the macrovoid (51).

[0105] 14. A women's hygiene pad according to either Example 12 or 13, wherein the reinforcing material has an xy surface area mainly located in front of the horizontal axis (200).

[0106] 15. A women's hygiene pad according to any one of Examples 12 to 14, wherein the reinforcing material has an xy surface area located at least partially, more preferably mainly, between the left and right front path sections (50f).

[0107] 16. A feminine hygiene pad according to any one of Examples 1 to 15, wherein the foam layer has an xy-plane surface area, and a portion, preferably the majority, of the pad, including the xy-plane surface area of ​​the foam layer located behind the transverse axis (200), is mechanically deformed.

[0108] 17. A feminine hygiene pad according to any one of Examples 1 to 16, wherein the foam layer has an xy-plane surface area, and a portion, preferably the majority, of the pad, including the xy-plane surface area of ​​the foam layer located laterally outward in the left and right front path sections (50f), is mechanically deformed.

[0109] *** The dimensions and values ​​disclosed herein should not be understood as being strictly limited to the exact numerical values ​​listed. Instead, unless otherwise specified, each such dimension is intended to mean both the listed value and the functionally equivalent range encompassing that value. For example, a dimension disclosed as "40 mm" is intended to mean "approximately 40 mm."

[0110] All documents referenced herein, including all cross-referenced or related patents or patent applications, and any patent applications or patents on which this application claims priority or benefit thereof, are incorporated herein by reference in their entirety, to the extent that they do not contradict this and unless explicitly stated to exclude or limit them. No citation of any document shall be deemed prior art to any invention disclosed or claimed herein, nor shall any such invention be taught, suggested, or disclosed, either alone or in combination with any one or more other references. Furthermore, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in any document incorporated by reference, the meaning or definition given to that term in this document shall prevail.

[0111] While 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 can be made without departing from the spirit and scope of the invention. Therefore, it is intended that all such changes and modifications within the scope of the invention be covered in the appended claims.

Claims

1. These are women's hygiene pads, A front end, a rear end, a vertical axis and a horizontal axis, wherein the axes intersect at a point, Liquid permeable top sheet, Liquid-impermeable backsheet, The system comprises an absorbent layer disposed between the top sheet and the back sheet, The absorption layer includes a layer of open-cell foam having a thickness in the z direction and an outer circumference along the x-y plane, the layer of open-cell foam includes arrangements of macrovoids therein, the macrovoids have a depth in the z direction, and the arrangement of the macrovoids defines paths located along the x-y plane of the layer of open-cell foam. A left-front path section is mainly located in front of the horizontal axis, starting at a left-center position close to the intersection of the axes, and ending at a left-outer position located in front of the first left-center position and further outward on the vertical axis than the first left-center position, A women's hygiene pad comprising: a right-front path section mainly positioned in front of the horizontal axis, beginning at a right-center position close to the intersection of the axes, positioned in front of the first right-center position, and ending at a right-outer position further outward on the vertical axis than the first right-center position.

2. The feminine hygiene pad according to claim 1, wherein the arrangement of the macrovoids further includes a rear path section substantially along the vertical axis and mainly located behind the horizontal axis.

3. The feminine hygiene pad according to claim 1 or 2, wherein the absorbent layer includes an arrangement of one or more front holes located along the x-y plane of the pad, the front holes being located between the left front path section and the right front path section.

4. A women's hygiene pad according to any one of claims 1 to 3, wherein the z-direction depth of a portion of the macrovoid extends entirely through the thickness of the foam layer.

5. A women's hygiene pad according to any one of claims 1 to 3, wherein the z-depth of a portion of the macrovoid is 40% to 70% of the thickness of the foam layer, and the z-depth begins on the side of the foam layer facing the wearer and extends from there.

6. A women's hygiene pad according to any one of claims 1 to 5, wherein one or more of the aforementioned path sections traverse at least four macrovoids.

7. A women's hygiene pad according to any one of claims 1 to 6, wherein each of the macrovoids along each of the path sections has a width, and the width is equal to 20% to 200% of the thickness in the z direction.

8. The women's hygiene pad according to any one of claims 1 to 7, wherein the open-cell foam is one or more of HIPE foam and polyurethane foam.

9. A women's hygiene pad according to any one of claims 1 to 8, wherein the arrangement of the macrovoids further includes a second left-front path section located outside the left-front path section.

10. The women's hygiene pad according to claim 9, wherein the second left-front path section extends substantially parallel to the left-front path section.

11. The women's hygiene pad according to claim 10, wherein the left front path section and the second left front path section are separated by a distance of 2 mm to 4 mm.

12. The feminine hygiene pad according to claim 9, wherein the arrangement of the macrovoids further includes a second right-front path section.

13. The women's hygiene pad according to claim 12, wherein the second right-front path section extends substantially parallel to the right-front path section.

14. A women's hygiene pad according to any one of claims 1 to 13, further comprising a reinforcing material located beneath one or more portions of the absorbent layer.

15. A women's hygiene pad according to any one of claims 1 to 14, wherein the ratio of the macrovoid length to the gap length in at least one of the left front path section and the right front path section is about 30:1 to about 1:5.

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