Patent Description:
Disposable diapers such as pad-type, tape-type, and underpants-type diapers, as well as sanitary napkins are known as absorbent articles. Such absorbent articles are typically configured to include a liquid-permeable topsheet, a liquid-impermeable backsheet, and an absorbent body provided between the topsheet and the backsheet.

In the absorbent article, in order to utilize not only the area in which a biofluid is discharged and its surroundings, but the whole absorbent body, the absorbent body preferably has an improved biofluid diffusibility, and therefore a variety of configurations have been proposed. As an example, a conventional configuration is known that includes an absorbent body in which a groove extending in the front-rear direction is provided, to facilitate a transfer of biofluid in the front-rear direction (see Patent Literature <NUM>, for example).

<CIT> discloses an interlabial sanitary pad including a pickup module containing an absorbent which is adapted to fit in or adjacent to a vaginal opening, a capacity module containing an absorbent which is adapted to be positioned remote from the vaginal opening, and fluid-wicking fibers serving as the absorbent and further communicating with both the pickup and capacity modules for carrying fluid from the pickup module to the capacity module. The fluid-wicking fibers are longitudinally oriented and packed in the capacity module at a bulk density greater than in the pickup module. The pickup module has a fluid-pervious cover, while the capacity module has a fluid-impervious baffle capable of containing fluid therein. The capacity module can have a flattened fan shape and can contain superabsorbent.

<CIT> relates to an absorbent body for absorbing body fluids. The body is generally planar and elongated and is surrounded by a substantially uniformly compressed peripheral edge.

<CIT> relates to an absorbent structure in an absorbent article, such as a diaper, an incontinence guard, a sanitary napkin or like article. The structure includes a liquid-acquisition and liquid-dispersing core of high bulk, porous material. The core is in liquid communication with a liquid storage part that surrounds the core at least along its longitudinally extending side-edges and which has a mean pore size that is smaller than the mean pore size of the high bulk, porous core. The density of the liquid storage part increases in a direction out towards the longitudinally extending side-edges of the absorbant structure.

<CIT> relates to an absorbent structure containing loosely compacted cellulosic fibers, which structure is particularly suitable for use in absorbent products requiring a substantial liquid holding capacity.

However, with the configuration only having a groove as described in Patent Literature <NUM>, the biofluid may be transferred rearward very rapidly when a large amount of biofluid is discharged all at once. In that case, the amount of the absorbed biofluid may be uneven between the front and the rear of the absorbent body, which may even hinder the utilization of the entire absorbent body.

In view of above, an object is to provide an absorbent article in which a biofluid can be transferred at an appropriate rate, so as to utilize a greater extent of the absorbent body in the front-rear direction. This object is solved by the absorbent article according to the independent claim. Further embodiments of the absorbent article are the subject of the further claims. Thus, the present invention is set out by the set of appended claims. In the following, parts of the description and drawing referring to examples, which are not covered by the claims are not presented as embodiments of the invention, but as illustrative examples useful for understanding the invention.

In one embodiment of an absorbent article, the absorbent article includes a liquid-permeable topsheet, a liquid-impermeable backsheet, and an absorbent body provided between the topsheet and the backsheet, wherein the absorbent body includes a crotch-corresponding region corresponding to the wearer's crotch when worn, and a front region being adjacent to and forward of the crotch-corresponding region, and a rear region being adjacent to and rearward of the crotch-corresponding region, and has a variable-density portion in which the density increases stepwise or gradually from a front toward a rear, the variable-density portion being provided in a region extending at least from the crotch-corresponding region to the rear region. The variable-density portion includes a low-density portion, a medium-density portion, and a high-density portion from the front toward the rear. The absorbent body includes a groove in a front-rear direction. A part in which the groove is provided includes the variable-density portion.

According to the embodiment, the absorbent article is provided in which biofluid can be transferred at an appropriate rate, so as to utilize a greater extent of the absorbent body in the front-rear direction.

Here, a variable-density portion having a density increasing from the front to the rear, and being provided in the region at least extending from the crotch-corresponding region to the rear region, enables the biofluid to be induced from the front to the rear. Accordingly, even when a large amount of biofluid is discharged at a stretch, the absorbent body in the rear region can be sufficiently utilized to prevent biofluid leakage from the lateral sides of the crotch-corresponding region. In this embodiment, the variable-density portion has the density that varies stepwise or gradually, so that the biofluid can be induced rearwardly at an appropriate rate. This allows for the effective utilization of both the crotch-corresponding region and the rear region.

Further, the groove enables an easy transfer of the biofluid along the groove in the front-rear direction, thereby promoting the above-described diffusion of the biofluid from the front toward the rear. Further, because the variable-density portion includes a low-density portion, a medium-density portion, and a high-density portion from the front to the rear, the biofluid can be diffused rearwardly along the groove at an appropriate rate that is not too fast, and both the crotch-corresponding region and the rear region can be effectively utilized.

According to one embodiment of the absorbent article, the variable-density portion is located in a middle region, the middle region being located in a middle in a width direction perpendicular to the front-rear direction and including a biofluid discharge opening corresponding portion corresponding to a biofluid discharge opening of a wearer when worn.

Here, the variable-density portion is located in the middle region. With this configuration, the biofluid in a certain amount can be immediately absorbed at the location where the biofluid is discharged in a normal wearing state, and can be successfully rearwardly diffused.

According to one embodiment of the absorbent article, the thickness of the medium-density portion is greater than the thickness of the low-density portion and the thickness of the high-density portion.

Here, the thickness of the medium-density portion is greater than the thickness of the high-density portion and the thickness of the low-density portion. Therefore, the groove is less likely collapse, even when a force is applied laterally.

According to one embodiment of the absorbent article, the variable-density portion includes a low-density portion, a medium-density portion, and a high-density portion from the front toward the rear, wherein the absorbent body includes a groove extending in the front-rear direction, the groove including a front groove and a rear groove provided separately in a front-rear direction, and wherein a part in which the front groove is provided includes the low-density portion, and a part in which the rear groove is provided includes the high-density portion, and wherein a part between the part in which the front groove is provided and the part in which the rear groove is provided includes the medium-density portion.

Here, because the front groove and the rear groove are provided, the biofluid can be easily transferred in the front-rear direction along each groove, thereby promoting the above-described diffusion of the biofluid from the front to the rear. Further, because the front groove and the rear groove are separately provided in the front-rear direction, the groove is less likely collapse even when a force is applied laterally. In addition, because the part in which the front groove is provided includes a low-density portion, and the part in which the rear groove is provided includes a high-density portion, and the intermediate part includes a medium-density portion, the biofluid can be transferred rearwardly along the groove at an appropriate rate which is not too fast, and both the crotch-corresponding region and the posterior region can be effectively utilized.

According to one embodiment of the absorbent article, the medium-density portion is provided in the rear region.

Here, the medium-density portion is provided in the rear region, so that the variable-density portion can be disposed in a well-balanced manner in the front-rear direction.

According to one embodiment of the absorbent article, the medium-density portion has a trapezoidal shape in a cross-section cut along the front-rear direction.

Here, in a cross-section along the front-rear direction, the medium-density portion has a trapezoidal shape. With this configuration, the fluid that has traveled on the surface of the absorbent body and reached the medium-density portion may be less likely accumulated in font of the medium-density portion, thereby allowing the biofluid to appropriately rearwardly transfer.

Examples of the present disclosure will now be described with reference to the drawings. In each drawing, unless otherwise noted, the same or corresponding elements may be indicated with same reference number, and the description therefore may not be repeated.

<FIG> shows an overhead view of an absorbent article <NUM> according to an example of the present disclosure. <FIG> shows a cross-sectional view taken along the line I-I in <FIG>. In this example, a pad-type disposable diaper (urine collection pad) is illustrated as an example.

As shown in <FIG> and <FIG>, the absorbent article <NUM> includes a liquid-permeable topsheet <NUM>, a liquid-impermeable backsheet <NUM>, and an absorbent <NUM> provided between the sheets <NUM> and <NUM>. As shown in <FIG>, the absorbent body <NUM> may be wrapped with a wrapping sheet <NUM> made of a nonwoven fabric, crepe paper, or the like. The wrapping sheet <NUM> may be uncolored (or white) or colored. When the absorbent article <NUM> is worn, the topsheet <NUM> side is the skin side, and the backsheet <NUM> side is secured to an outer diaper (an outside diaper), an underwear, or the like.

In this example, the absorbent article <NUM> has an elongated shape as a whole in a planar view. That is, the absorbent article <NUM> has a predetermined length in a first direction (the front-rear direction or the longitudinal direction) D1 and a predetermined width in a second direction (the width direction) D2 perpendicular to the first direction D1, and the predetermined width is smaller than the predetermined length. The front and the rear of the absorbent article <NUM> respectively correspond to the ventral side and the dorsal side when the absorbent article is worn. The shape of the absorbent article <NUM> may be line-symmetric with respect to a front-rear direction centerline CL as shown in the drawings, or may be non-line-symmetric. The configuration of the absorbent article <NUM> (including the thickness, the basis weight of the absorbent body, the groove, etc.) may also be line-symmetric or non-line-symmetric.

As shown in <FIG>, the absorbent article <NUM> has a crotch-corresponding region B1 substantially in the middle in the front-rear direction D1. In this specification, the "crotch-corresponding region" means a portion corresponding to the body's crotch (groin) during use of the absorbent article. For example, the crotch-corresponding region B1 may extend from the middle in the front-rear direction of the absorbent article or its proximity to a predetermined position in the front, or may extend over a predetermined extent in the middle in the front-rear direction of the absorbent article. In the illustrated example, the absorbent article <NUM> includes a constricted portion having a smaller width, and a part of a region in which the constricted portion is formed corresponds to the crotch-corresponding portion. Further, a region adjacent to the front of the crotch-corresponding region B1 and extending to the front edge of the absorbent article <NUM>, is the front region A1. A region adjacent to the rear edge of the crotch-corresponding region B1 and extending to the rear edge of the absorbent article <NUM> is the rear region C1.

As described above, the absorbent article <NUM> is not limited to a planar shape with a portion having a smaller width than the front and rear regions (i.e., a constricted portion), but may have another shape, such as a rectangular shape that has a constant width in the front-rear direction D1.

The entire length (the length in the front-rear direction D1) of the absorbent article <NUM> may be approximately <NUM> to <NUM>, and the entire width (the length in the width direction D2) may be approximately <NUM> to <NUM>. Further, the length of the crotch-corresponding region B1 in the front-rear direction D1 may be approximately <NUM> to <NUM>, the length of the rear region A1 in the front-rear direction D1 may be approximately <NUM> to <NUM>, and the length of the rear region C1 in the front-rear direction D1 may be approximately <NUM> to <NUM>. When the absorbent article <NUM> has a constricted portion, the minimum width of the absorbent article <NUM> is approximately <NUM> to <NUM> % with respect to the entire width (the length in the width direction D2 in the portion forward of or rearward of the constricted portion).

As shown in <FIG>, the size of the backsheet <NUM> may be larger than the absorbent body <NUM>. The absorbent body <NUM> may be arranged within the area of the backsheet <NUM>. The liquid-impermeable backsheet <NUM> may include a polyethylene film or the like, or may be a sheet having a moisture-permeability without impairing a water shielding property to prevent stuffiness. An example of such water shielding/moisture-permeable sheet includes a microporous sheet. The microporous sheet may be obtained by melt-kneading an olefin resin such as polyethylene or polypropylene with an inorganic filler to form a sheet, and subsequently stretching the sheet in a uniaxial direction or biaxial directions. The outer surface of the backsheet <NUM> may be covered with an outer sheet, such as a nonwoven fabric.

The topsheet <NUM> is disposed on the topside of the absorbent body <NUM>. In the illustrated example, the topsheet <NUM> does not cover a part of the ends of the width direction D2 of the absorbent <NUM> body, but the topsheet <NUM> may cover the entire absorbent body <NUM>. The topsheet <NUM> may include a porous or nonporous nonwoven fabric, a perforated plastic sheet, and the like. Examples of material fibers forming the nonwoven fabric may include synthetic fibers such as olefin-based fibers including polyethylene and polypropylene, polyester-based fibers, amide-based fibers, and the like, as well as regenerated fibers such as rayon and cupra, and natural fibers such as cotton.

As shown in <FIG> and <FIG>, an intermediate sheet <NUM> can be interposed between the topsheet <NUM> and the absorbent body <NUM>. The intermediate sheet <NUM> prevents reversal of the biofluid once absorbed in the absorbent body <NUM>. Therefore, the intermediate sheet <NUM> may preferably be made of a material having a low water-retention property and a high liquid-permeability, such as a variety of nonwoven fabrics, a mesh film, or the like.

At both ends of the front-rear direction D1 of the absorbent body <NUM>, the backsheet <NUM> and the topsheet <NUM> are bonded with each other. Further, gather sheets <NUM>, <NUM> are each provided on lateral ends of the absorbent article <NUM> along the front-rear direction D1, and the backsheet <NUM> and the gather sheets <NUM>, <NUM> are bonded with each other on each lateral side of the width direction D2 of the absorbent article <NUM>.

Suitable material for the gather sheet <NUM> may include a plastic sheet, a melt-blown nonwoven fabric, or the like may be used. However, in order to provide a comfortable touch to the skin, the nonwoven fabric treated with water-repellent material such as silicone may preferably be used.

As shown in <FIG> and <FIG>, the gather sheets <NUM>, <NUM> are each superimposed on the topsheet <NUM>. The inner end of the width direction D2 of each gather sheet <NUM> may be provided with an elastic member that is attached in its stretched state along the front-rear direction D1 to the sheet. The elastic member may be manufactured from a styrene-based rubber, an olefin-based rubber, a urethane-based rubber, an ester-based rubber, or the like, to form a thread, a string, a band, etc..

The gather sheet <NUM> may also be bonded to the topsheet <NUM>, the wrapping sheet <NUM>, or the backsheet <NUM> disposed directly under the gather sheet <NUM> in the zone shown by a linear hatching in <FIG>. Because the inner end of the width direction D2 of the gather sheet <NUM> may be provided with an elastic member as described above, the unbonded portion in each gather sheet <NUM> (i.e., the inner region in the width direction D2 excluding the front and rear edges of the gather sheet <NUM>) can stand from the topside (the topsheet side) of the absorbent article <NUM> to form each of gathers G, G. The gathers G, G enable the prevention of lateral leakage of biofluids.

The bonding between the gather sheets <NUM>, <NUM> and the components thereunder can be formed, for example, by a hot-melt adhesive, a heat sealing, or an ultrasonic sealing.

The absorbent body <NUM> may be a stacked fibrous body of pulp fibers, an assembly of filaments such as cellulose acetate, a nonwoven fabric, or the like. A superabsorbent polymer in particulate form may be mixed to or fixed to the absorbent body, as necessary. When the superabsorbent polymer particles are mixed, the absorbent body <NUM> may preferably be wrapped in a wrapping sheet <NUM> to prevent spillage of the particulates.

The basis weight of the fiber and the basis weight of the superabsorbent polymer in the absorbent body <NUM> may be appropriately determined. However, the basis weight of the fiber may preferably be approximately <NUM> to <NUM>/m<NUM>, and the basis weight of the absorbent polymer may preferably be approximately <NUM> to <NUM>/m<NUM>. The thickness of the absorbent body <NUM> (the thickness of a part excluding a grooved part, which is an average value if the thickness is not uniform) may be approximately <NUM> to <NUM>, or may be approximately <NUM> to <NUM>.

<FIG> shows a planar view of the absorbent body <NUM>. As shown in <FIG>, the absorbent body <NUM> has an elongated shape as a whole, in the same manner as the absorbent article <NUM>. As illustrated in <FIG>, the absorbent body <NUM> may be line-symmetric in shape and configuration with respect to the front-rear direction centerline CL, but the shape and configuration of the absorbent body <NUM> may not necessarily be line-symmetric. Further, as illustrated in <FIG>, the absorbent body <NUM> has a crotch-corresponding region B2 substantially in the middle in the front-rear direction D1, and this crotch-corresponding region B2 corresponds to the above-described crotch-corresponding region B1 of the absorbent article <NUM>. The region adjacent to the front of the crotch-corresponding region B2 and extending to the front edge of the absorbent body <NUM> is the front region A2, and the region adjacent to the rear of the crotch-corresponding region B2 and extending to the rear edge of the absorbent body <NUM> is the rear region C2.

In the same manner as the whole shape of the absorbent article <NUM> in a planar view, the absorbent body <NUM> may be shaped to have a constricted portion, but may be in a rectangular shape or the like having a constant width and having no constricted portion over the front-rear direction D1, regardless of the shape of the absorbent article <NUM> in a planar view. When the absorbent body <NUM> has a constricted portion as in the illustrated example, the minimum width of the constricted portion may be approximately <NUM> to <NUM> % with respect to the length of the portion forward of or rearward of the constricted portion in the width direction D2.

The crotch-corresponding region B2 of the absorbent body <NUM>, which may form a part of the above-described constricted portion, may be provided in the front half of the absorbent body <NUM> as illustrated, or may be provided in the middle of the front-rear direction D1 of the absorbent body <NUM>, depending on the overall configuration of the product.

As illustrated in <FIG>, the absorbent body <NUM> has a variable-density portion <NUM>, in which the density varies, at least in the region extending from the crotch-corresponding region B2 to the rear region C2. The variable-density portion <NUM> is a portion of the absorbent body <NUM> in which the density increases stepwise or gradually from the front toward the rear. The density of the variable-density portion <NUM> may be varied based on the fibers or filaments contained in the absorbent body <NUM> (i.e., a fiber density).

The range over which the variable-density portion <NUM> extends in the front-rear direction D1 is not particularly limited, as long as the variable-density portion <NUM> is provided at least in the region extending from the crotch-corresponding region B2 to the rear region C2 as described above. For example, the variable-density portion <NUM> may not necessarily be in the front region A1, and may extend from any position in the crotch-corresponding region B2 to any position in the rear region C2. The entire absorbent body <NUM> may be the variable-density portion <NUM>. However, the front edge of the variable-density portion <NUM> may be positioned forwardly at a distance from the rear edge of the crotch-corresponding region B2, the distance being preferably two-thirds or more, more preferably three-fourths or more with respect to the length of the crotch-corresponding region B2 in the front-rear direction D1. In addition, the front edge of the variable-density portion <NUM> may preferably be at or beyond the front edge of the crotch-corresponding region B2. The variable-density portion <NUM> preferably extends in a range that includes the biofluid discharge opening corresponding portion Q, which will be later described.

In the illustrated example, the variable-density portion <NUM> extends from the rear of the front region A2 to the vicinity of the rear edge of the rear region C2 across the entire crotch-corresponding region B2. The rear edge of the variable-density portion <NUM> may be positioned at the same position as the rear edge of the absorbent body <NUM>. However, in order to prevent rearward leakage, the rear edge of the variable-density portion <NUM> may be positioned <NUM> to <NUM>, preferably <NUM> to <NUM> forward from the rear edge of the absorbent body <NUM>.

The planar shape of the variable-density portion <NUM> is not particularly limited, but may substantially be along the contour of the absorbent body <NUM> in a range over which the variable-density portion <NUM> extends. For example, as in the example illustrated in <FIG>, the variable-density portion <NUM> has a smaller width in the front and a lager width in the rear. According to the example illustrated in <FIG>, the front edge of the variable-density portion <NUM> extends in parallel to the width direction D2. However, the front edge may be forwardly convex in the front-rear direction D1, or more forwardly projected as it approaches the front-rear direction centerline CL. The same applies to the rear edge of the variable-density portion <NUM>.

In a state in which the absorbent article is worn in the normal manner, biofluid (such as urine) is drained in the region from the front to the middle of the crotch-corresponding region B2. In other words, the biofluid discharge opening corresponding portion Q corresponding to the biofluid discharge opening such as urethral opening of the wearer when worn, is located substantially from the front to the middle of the crotch-corresponding region B2. In an absorbent article in which the variable-density portion is not provided in the absorbent body, when a large amount of biofluid is discharged at a stretch, the biofluid can only radially spread from the position at which the absorbent body comes into contact with the biofluid, and it is difficult to direct the biofluid in a predetermined direction. Therefore, the biofluid may fail to be absorbed within the cotch corresponding region, and may be leaked laterally. In contrast, according to the present example, the absorbent article <NUM> has the variable-density portion <NUM> in which the density is increased from the front toward the rear, so that the biofluid can be directed from the front to the rear by a difference in capillary force in the absorbent body.

In the example illustrated in <FIG>, the variable-density portion <NUM> includes a low-density portion <NUM>, a medium-density portion <NUM> and a high-density portion <NUM> disposed from the front to the rear. The low-density portion <NUM> is a portion having a relatively lower density in the variable-density portion <NUM>, the high-density portion <NUM> is a portion having a relatively high density in the variable-density portion <NUM>, and the medium-density portion <NUM> is a portion having a density between the low-density portion <NUM> and the high-density portion <NUM>. The densities of the low-density portion <NUM>, the medium-density portion <NUM>, and the high-density portion <NUM> are relative densities. The low-density portion <NUM>, the medium-density portion <NUM>, and the high-density portion <NUM> each may have a uniform density within each portion, or may have a density varying stepwise or gradually within each portion.

In the illustrated example, the variable-density portion <NUM> is configured to have a rearwardly stepwise increasing density. However, the variable-density portion <NUM> may be configured to have a rearwardly gradually increasing (continuously increasing) density.

Because the variable-density portion <NUM> has a stepwise or gradually varying density, the biofluid can be induced rearwardly at an appropriate transfer rate, thereby reducing the area in which the biofluid is transferred at an excessively high rate. This reduces a part of the absorbent body through which biofluid passes without being sufficiently utilized for absorption, and allows for the effective utilization at least of both the crotch-corresponding region B2 and the rear region C2. Thus, the absorbent body <NUM> can be utilized in a greater extent in the front-rear direction D1.

The density of the low-density portion <NUM> may be approximately <NUM> to <NUM>/m<NUM>, the density of the medium-density portion <NUM> may be approximately <NUM> to <NUM>/m<NUM>, and the density of the high-density portion <NUM> may be approximately <NUM> to <NUM>/m<NUM>. Each of these densities of the low-density portion <NUM>, the medium-density portion <NUM>, and the high-density portion <NUM> may be a uniform density within each portion, or may be varied stepwise or gradually within each portion.

In the specification, the density of the absorbent body can be measured as follows. A part to be measured is cut out from the absorbent body to have a predetermined size, and the area and the weight of the part are measured. Further, the thickness is measured by using a thickness measuring instrument ("Peacock", model number: FFD-<NUM>, manufactured by Ozaki Mfg. ), for example. The density can be calculated from the area, the thickness and the weight measured as above.

The variable-density portion <NUM> can be formed using any conventional method. For example, fibers may be stacked in a fiber stacking process so as to have a greater basis weight in an area in which a higher density is desired in the absorbent body, and then pressed by press rolls with no protrusion or depression. Alternatively, fibers may be stacked so as to have a homogeneous basis weight as a whole, and then pressed by press rolls that have a protrusion corresponding to an area in which a higher density is desired in the absorbent body. The latter case results in a difference in thickness within the variable-density portion <NUM>. In addition, the variation in density can also be achieved by using different materials to form the low-density portion <NUM>, medium-density portion <NUM>, and high-density portion <NUM>.

<FIG> shows a planar view of another absorbent body <NUM> in the example. In the same manner as the absorbent body <NUM> illustrated in <FIG>, the absorbent body <NUM> also has a variable-density portion <NUM>. The variable-density portion <NUM> has a low-density portion <NUM>, a medium-density portion <NUM>, and a high-density portion <NUM> from the front toward the rear. The absorbent body <NUM> differs from the absorbent body <NUM> (illustrated in <FIG> and <FIG>) in that the size and the shape of the variable-density portion <NUM> are different. The variable-density portion <NUM> in the absorbent body <NUM> has a smaller width than the variable-density portion <NUM> of the absorbent body <NUM>. Further, the variable-density portion <NUM> has the same width along the front-rear direction D1.

<FIG> illustrates a middle region D including the biofluid discharge opening corresponding portion Q, and lateral regions E and E' each outwardly adjacent to the middle region D in the width direction D2. The variable-density portion <NUM> is arranged so as to correspond to the middle region D. The variable-density portion <NUM> may extend over the middle portion D, or may have a width smaller than that of the middle region D and extend within the middle region D. In either case, the variable-density portion <NUM> is preferably provided at least in the middle region D. This arrangement allows the biofluid to be absorbed immediately at the position where the biofluid is discharged when the absorbent article is worn in the normal manner, and to be effectively dispersed rearwards. The width and the size of the middle region D and the lateral regions E and E' are illustrated only by way of example in the present specification and the drawing, but may depend on the type of absorbent article, the purpose of use (health condition, and sex of the target wearer for the absorbent article), etc. The length of the middle region D may be approximately <NUM> to <NUM> in the width direction D2.

In the examples illustrated in <FIG> and <FIG>, a region other than the variable-density portion <NUM>, <NUM>, which has no density variation (i.e., a region with a substantially uniform density), is provided around the variable-density portion <NUM>, <NUM>. In other words, the density is substantially uniform in a region other than the variable-density portion <NUM>, <NUM>. The density of the absorbent body <NUM>, <NUM> in a constant density region, is not particularly limited, but preferably has a density lower than the density of the highest density region in the variable-density portion <NUM>, <NUM>. The density of the region without a density variation may also have a density similar to the average density in the variable-density portion <NUM>, <NUM>, or may have a density equivalent to the average density of the density in a location having a highest density and the density in a location having a lowest density in the variable-density portion <NUM>, <NUM>. Alternatively, the region without a density variation may have the same density as the density in any of the low, medium, and high-density portions, or may have the density different from the density in either of the low, medium, and high-density portions. The above density may be an average density in the portion when there is a density difference within the portion.

Further, the thickness of the region without a density variation, which is the region other than the variable-density portion <NUM>, <NUM>, is not particularly limited, and may be larger or smaller than the variable-density portion <NUM>, <NUM>. When there is a thickness difference in the variable-density portion <NUM>, <NUM>, the region without a density variation may have a thickness less than the greatest thickness of the variable-density portion <NUM>, <NUM>, or a thickness greater than the smallest thickness of the variable-density portion <NUM>, <NUM>.

<FIG> shows a planar view of the absorbent body <NUM> in another example. In addition, <FIG> shows a cross-sectional view taken along the II-II line in <FIG>. The absorbent body <NUM> has a variable-density portion <NUM>, and the variable-density portion <NUM> has a low-density portion <NUM>, a medium-density portion <NUM>, and a high-density portion <NUM> from the front to the rear, in the same manner as in the absorbent body <NUM> (<FIG> and <FIG>) and the absorbent body <NUM> (<FIG>) described above. However, as illustrated in <FIG> and <FIG>, the absorbent body <NUM> differs from the absorbent bodies <NUM> and <NUM> in that the absorbent body <NUM> has a groove <NUM>. The groove <NUM> is a depression toward the backsheet side and lower than the surrounding region. As illustrated in <FIG> and <FIG>, a part of the absorbent body <NUM> in which the groove <NUM> is provided, has the variable-density portion <NUM>. More specifically, the part in which the groove <NUM> is provided, or the part with the groove <NUM> is the variable-density portion <NUM>. In other words, a low-density portion <NUM>, a medium-density portion <NUM>, and a high-density portion <NUM> are formed within the part in which the groove <NUM> is provided.

As shown in <FIG>, the groove <NUM> extends in the front-rear direction D1 in the absorbent body <NUM>. Specifically, the groove <NUM> is formed along the front-rear direction centerline CL to straddle the front-rear direction centerline CL in the width direction D2. In the illustrated example, the groove <NUM> is a single groove extending in the front-rear direction, but may include a plurality of grooves extending in the front-rear direction. In either case, the groove <NUM> is preferably disposed within the middle region D or near the middle region D. Because the groove <NUM> may be located within the middle region D as illustrated in <FIG>, a part of the biofluid can be immediately absorbed at the position where the biofluid is discharged, and unabsorbed biofluid can be directed rapidly rearward.

The width of the groove <NUM> is preferably <NUM> to <NUM>, and more preferably <NUM> to <NUM>. The width of the groove <NUM> may be constant along the front-rear direction D1 as shown in <FIG>, but may vary. For example, the width of the groove <NUM> may be gradually forwardly or rearwardly increased or decreased. The groove may meander, or may be formed in a regular or irregular wavy line.

The groove <NUM> may extend from the front edge of the absorbent body <NUM> to the rear edge, but preferably the front edge of the groove <NUM> is located <NUM> to <NUM> rearward from the front edge of the absorbent body <NUM>. Further, the rear edge of the groove <NUM> is located <NUM> to <NUM> forward of the rear edge of the absorbent body <NUM>. These may ensure a certain absorption capacity of the absorbent body <NUM> and also maintain the shape of the absorbent body <NUM>.

In the part in which the groove <NUM> is provided, the thickness of the absorbent body <NUM> is uniform. However, the thickness is not necessarily constant. The thickness of the absorbent body <NUM> within the part with groove <NUM> is not particularly limited as long as the thickness is less than that of the surrounding area. For example, the thickness of the absorbent body <NUM> in the part with the groove <NUM> may be gradually reduced from the front to the rear. In such case, the cross-sectional shape of the groove <NUM> cut along the front-rear direction D1 may be a long triangle in the front-rear direction D1.

The thickness of the absorbent body in the part with the groove <NUM> may be <NUM> to <NUM>%, preferably <NUM> to <NUM>%, of the thickness of the surrounding area, i.e., the thickness of the absorbent body in the part provided with no groove.

In the example illustrated in <FIG> and <FIG>, a part in which the groove <NUM> is not provided is a portion having no varied density, or a portion other than the variable-density portion <NUM>. However, the variable-density portion may be formed also in the part in which the groove <NUM> is not provided in the absorbent body. In that case, the region other than the part with the groove <NUM> in the absorbent body may have a density stepwise or gradually increasing from the front to the rear. Further, in the absorbent body, the density in the part in which the groove <NUM> is provided may be substantially the same as the density in the part in which the groove <NUM> is not provided.

<FIG> shows a variation of the absorbent body <NUM>. The example illustrated in <FIG> has the same basic structure as in the example illustrated in <FIG> and <FIG>, but differs in that the former has a raised part in the middle in the front-rear direction D1. In the example illustrated in <FIG>, the thickness DM of the medium-density portion <NUM> is higher than the thickness DL of the low-density portion <NUM> located forward of the medium-density portion <NUM> and the thickness DH of the high-density portion <NUM> rearward of the medium-density portion <NUM>. The greater thickness in the middle of the groove <NUM> prevents the groove <NUM> from collapsing even when the absorbent body <NUM> deforms due to the force from both lateral sides when the absorbent article is worn. In the example illustrated in <FIG>, the thickness DL of the low-density portion <NUM> and the thickness DH of the high-density portion <NUM> are the same, but they may be different from each other.

The thickness DL of the low-density portion <NUM> may be <NUM> to <NUM> % and preferably <NUM> to <NUM> % of the thickness DM of the medium-density portion <NUM>. The thickness DH of the high-density portion may also be <NUM> to <NUM> %, and preferably <NUM> to <NUM> % of the thickness DM of the medium-density portion <NUM>.

In the example illustrated in <FIG>, the medium-density portion <NUM> is preferably located in the rear region C2. In this configuration, the medium-density portion <NUM>, which is relatively thicker than the thickness in the portion forward thereof and the portion rearward thereof and is protruded from the skin side, is not located in the crotch-corresponding region B2, in which the absorbent article can be more closely attached, but is located in the rear region C2 rearward of the crotch-corresponding region B2. This configuration is preferable in light of reducing uncomfortable feeling when the absorbent article is worn. Alternatively, the medium-density portion <NUM> can be located within the crotch-corresponding region B2. In this example, a portion having a greater thickness is provided in the crotch-corresponding region B2, in which the groove <NUM> is particularly likely to collapse. This configuration is preferable in light of preventing the groove <NUM> from collapsing.

In the example illustrated in <FIG>, the length of the front-rear direction D1 of the medium-density portion <NUM> may be <NUM> to <NUM>, preferably <NUM> to <NUM>. A length of <NUM> or more enables the groove to be less likely collapse even when a force is applied from the lateral side of the absorbent body <NUM>, thereby maintaining the function of the groove to induce the biofluid rearwardly. A length of <NUM> or less can prevent excessively reducing the soft part in the absorbent body <NUM>, and thus reducing the absorption capacity of the absorbent body <NUM>.

The grooved part illustrated in <FIG>, in which the thickness DM of the medium-density portion <NUM> is greater than the thickness DL of the low-density portion <NUM> forward of the medium-density portion <NUM> and the thickness DH of the high-density portion <NUM> rearward of the medium-density portion <NUM>, can be formed as follows. As illustrated in <FIG>, a stacked fibrous body is prepared to have a smaller basis weight only in an area in which the low-density portion <NUM> is desired to be formed. Subsequently, the above stacked fibrous body is pressed by using press rolls or a press machine having a shape as illustrated in the upper of <FIG>, i.e., a shape including a less protruded part corresponding to the area in which the medium-density portion <NUM> is be formed, and a more protruded part corresponding to the area in which the high-density portion <NUM> is to be formed. This allows the stacked fibrous body to be moderately compressed in the area in which the medium-density portion <NUM> is to be formed, and to be intensively compressed in the portion in which the high-density portion <NUM> is to be formed. As a result, an absorbent body <NUM> having a low-density portion <NUM>, a medium-density portion <NUM>, and a high-density portion <NUM> is formed as illustrated in <FIG>.

<FIG> shows the absorbent body <NUM> in another example. <FIG> shows a cross-sectional view taken along the III-III line in <FIG>. The absorbent body <NUM> has a variable-density portion <NUM>, and the variable-density portion <NUM> has a low-density portion <NUM>, a medium-density portion <NUM>, and a high-density portion <NUM> from the front to the rear, in the same manner as in the absorbent body <NUM> (<FIG> and <FIG>) described above. In addition, a groove extending from the front to the rear in the front-rear direction is also provided. However, as illustrated in <FIG> and <FIG>, the groove formed in the absorbent body <NUM> differs from the groove formed in the absorbent body <NUM> in that the former includes a front groove <NUM> and a rear groove <NUM> separately in the front-rear direction.

As illustrated in <FIG> and <FIG>, in the absorbent body <NUM>, a part in which the front groove <NUM> is provided may include a low-density portion <NUM> of the variable-density portion <NUM>, and a part in which the rear groove <NUM> is provided may include a high-density portion <NUM> of the variable-density portion <NUM>. The part of the absorbent body <NUM> between the front groove <NUM> and the rear groove <NUM> includes a medium-density portion <NUM>. That is, the absorbent body <NUM> is configured so that the part between the groove <NUM> and the groove <NUM> is the medium-density portion <NUM> of the variable-density portion <NUM>. Thus, in the absorbent body <NUM>, the distance between the groove <NUM> and the groove <NUM> in the front-rear direction D1 can be the length of the medium-density portion <NUM> in the front-rear direction D1. Further, as illustrated in <FIG>, the thickness DM of the medium-density portion <NUM> may be greater than the thickness DL of the low-density portion <NUM> located forward of the medium-density portion <NUM> and the thickness DH of the high-density portion <NUM> located rearward of the medium-density portion <NUM>.

As described above, the absorbent body <NUM> has a front groove <NUM> and a rear groove <NUM> separately in the front-rear direction D1, so that the biofluid which has been induced along the front groove <NUM>, can be controlled not to be transferred at a stretch to the rear groove <NUM>. Therefore, even when a large amount of fluid is discharged, the momentum of the fluid may be reduced in the medium-density portion <NUM> provided between the grooves. In addition, when forces are applied from the lateral sides, the groove is less likely collapsed and thus it is possible to maintain the function of the groove to rearwardly induce the biofluid when worn.

The width, the arrangement, the size, and the shape of the groove of the absorbent body <NUM> may be determined in the same manner as the groove of the absorbent body <NUM> described with reference to <FIG>. The location of the medium-density portion <NUM>, and also the configuration of the non-grooved part may be determined in the same manner as the absorbent body <NUM> described with reference to <FIG>.

<FIG> shows the absorbent body <NUM> in another example. The absorbent body <NUM> has, in the same manner as in the absorbent body <NUM> illustrated in <FIG> and <FIG>, a variable-density portion <NUM>, which includes a low-density portion <NUM>, a medium-density portion <NUM>, and a high-density portion <NUM> from the front to the rear. The absorbent body <NUM> also has a front groove <NUM> and a rear groove <NUM> separately formed in the front-rear direction. However, the absorbent body <NUM> differs from the absorbent body <NUM> (<FIG> and <FIG>) in that the former has the rear groove <NUM> whose width is rearwardly reduced.

In the absorbent body <NUM>, the wider front end of the rear groove <NUM> enables biofluid which has been flown behind the front groove <NUM> to easily enter into the rear groove <NUM>. Further, the biofluid can be more easily diffused from the rear edge of the rear groove <NUM> into the absorbent body rearward thereof, thereby allowing the rear of the absorbent body to be more effectively utilized.

Besides the width of the rear groove <NUM>, the other configuration of the absorbent body <NUM> may be determined in the same manner as the groove of the absorbent body <NUM> described with reference to <FIG> and <FIG>. The location of the medium-density portion <NUM> and the configuration of the non-grooved part may also be determined in the same manner as in the absorbent body <NUM> described with reference to <FIG>.

<FIG> shows a variation of the absorbent body <NUM> illustrated in <FIG> and <FIG>. The absorbent body <NUM> illustrated in <FIG> has a basic configuration similar to that of the absorbent body <NUM>. Specifically, the absorbent body <NUM> has a low-density portion <NUM>, a medium-density portion <NUM>, and a high-density portion <NUM> from the front toward the rear. The part in which the front groove <NUM> is provided includes a low-density portion <NUM>, the part in which the rear groove <NUM> is provided includes a high-density portion <NUM>, and a portion therebetween includes the middle-density portion <NUM>.

In the absorbent body <NUM>, the front groove <NUM> and the rear groove <NUM> have a different cross-sectional shape along the front-rear direction D1 from that in the absorbent body <NUM> (<FIG>). Specifically, in the illustrated example, the front groove <NUM> and the rear groove <NUM> of the absorbent body <NUM> are configured to have a shorter length in the front-rear direction D1 in the deeper position of the grooves. In other words, the font groove <NUM> and rear groove <NUM> are each shaped in a reverse trapezoid, in which the upper base is longer than the lower base. On the other hand, the medium-density portion <NUM> is shaped in a trapezoid.

<FIG> shows a deformed state of the absorbent body <NUM> when the absorbent article including the absorbent body <NUM> is worn. In <FIG>, the direction of the biofluid flow is illustrated with arrows. As described above, the biofluid which has been flown on the surface of the absorbent body <NUM> to the medium-density portion <NUM> may be controlled not to excessively rapidly flow toward the rear due to the medium-density portion <NUM>. In addition to the suppression of a rapid flow, it is also possible to prevent the biofluid from being accumulated in front of the medium-density portion <NUM>, because the medium-density portion <NUM> has a trapezoidal cross-sectional shape. This allows fluid to be rearwardly well transferred at an appropriate rate.

As illustrated in <FIG>, the absorbent body <NUM> may have different configurations between the front part and the rear part of the medium-density portion <NUM> of the absorbent body <NUM>, which are bordered by the center of the front-rear direction D1 (represented by line L1). For example, the material or basis weight of the absorbent body <NUM> may be different between the front part RF forward of the line L1 and the rear part RB rearward of the line L1. With this configuration, when the absorbent article is curved while being worn, the medium-density portion <NUM> of the absorbent article <NUM> easily bends in the middle in the front-rear direction D1, so that the absorbent article is easily deformed.

Claim 1:
An absorbent article (<NUM>) comprising:
a liquid-permeable topsheet (<NUM>);
a liquid-impermeable backsheet (<NUM>); and
an absorbent body (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) provided between the topsheet (<NUM>) and the backsheet (<NUM>), wherein the absorbent body (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) includes
a crotch-corresponding region (B1) corresponding to the wearer's crotch when worn,
a front region (A1) that is adjacent to and forward of the crotch-corresponding region (B1),
a rear region (C1) being adjacent to and rearward of the crotch-corresponding region (B1), and
has a variable-density portion (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) with a density increasing stepwise or gradually from a front toward a rear, the variable-density portion (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) being provided in a region extending at least from the crotch-corresponding region (B1) to the rear region (C1),
wherein the variable-density portion (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) includes a low-density portion (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), a medium-density portion (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), and a high-density portion (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) from the front toward the rear,
wherein the absorbent body (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) includes a groove (<NUM>, <NUM>, <NUM>) in a front-rear direction, and
wherein a part in which the groove (<NUM>, <NUM>, <NUM>) is provided includes the variable-density portion (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>).