AU2018310177B2

AU2018310177B2 - Absorbent article

Info

Publication number: AU2018310177B2
Application number: AU2018310177A
Authority: AU
Inventors: Takamasa MURAI; Haruki Toda
Original assignee: Unicharm Corp
Current assignee: Unicharm Corp
Priority date: 2017-08-01
Filing date: 2018-04-13
Publication date: 2022-07-21
Anticipated expiration: 2038-04-13
Also published as: CN110603018B; JP6479107B2; TW201909863A; TWI791516B; CN110603018A; WO2019026354A1; JP2019025148A; AU2018310177A1

Abstract

The present invention provides an absorbent article capable of causing less discomfort to a wearer and being less likely to give rise to skin conditions such as bedsores or rashes. This absorbent article comprises a surface sheet (5) and an absorber (6) and has a longitudinal direction, a width direction, and a thickness direction. The absorbent article further comprises: a low friction member (14) disposed on a skin-facing side of the surface sheet (5) at least in a rear region (4), and having a plurality of openings (16) that penetrate the absorbent article in the thickness direction; and a cover sheet (13) disposed on the skin-facing side of the low friction member (14). Furthermore, each of the plurality of openings (16) are specifically configured so as to have an opening periphery portion (17) disposed on the skin-facing side and a rib portion (18) protruding toward the non-skin-facing side from the opening periphery portion (17).

Description

DESCRIPTION TITLE ABSORBENT ARTICLE FIELD

[0001] The present invention relates to an absorbent article such as a urine-absorbing pad or disposable diaper, and particularly it relates to an absorbent article that is unlikely to produce skin conditions such as bedsores or rash on the skin of the wearer.

BACKGROUND

[0002] In recent years it has been attempted to employ various strategies for absorbent articles such as urine-absorbing pads and disposable diapers, to ameliorate skin conditions such as bedsores and rashes (dermatitis) produced in the skin of wearers.

[00031 PTL 1, for example, discloses one such absorbent article, as a disposable urine-absorbing pad with a bedsore-preventing function, comprising an outer surface sheet, an absorbent body provided on the body side of the outer surface sheet, an inner surface sheet provided on the body side of the absorbent body, a left side sheet provided on the left side of the pad, a right side sheet provided on the right side of the pad, an overlap sheet provided in the gluteal region and a low friction member with pores provided between the overlap sheet and the inner surface sheet, wherein the right side edge and left side edge of the overlap sheet are joined to the left side of the right side sheet and the right side of the left side sheet, respectively. The disposable urine absorbing pad disclosed in PTL 1 can be produced at low cost, and since the overlap sheet easily moves in the longitudinal direction relative to the inner surface sheet, it has a function of preventing creation or aggravation of bedsores.

[CITATION LIST] [PATENT LITERATURE]

[0004]

[PTL 1] Japanese Unexamined Patent Publication No. 2014-155609

SUMMARY [TECHNICAL PROBLEM]

[0005] However, when a liquid-impermeable low friction member is provided on the body side (skin-facing surface side) of the inner surface sheet (top sheet) as in the absorbent article disclosed in PTL 1, and excreted fluid such as urine that has been absorbed into the absorbent body situated on the non-skin-facing surface side of the top sheet is released from the absorbent body as humidity by evaporation, discharge of humidity becomes blocked at the portion covered by the liquid-impermeable low friction member (more specifically, the portion other than the open pores of the low friction member), and therefore migration of humidity has tended to create a wetted or musty state that is felt by the wearer, thus resulting in discomfort. In addition, when open pores are formed in the low friction member, and excreted fluid such as urine that has been absorbed by the absorbent body rewets to the skin-facing surface side, the excreted fluid has easily migrated to the skin-facing surface side through the open pores of the low friction member, thus wetting the skin of the wearer with the excreted fluid and producing discomfort for the wearer. Furthermore, when the skin of the wearer remains in a wetted state by excreted fluid such as urine or humidity resulting from it, the skin of the wearer becomes wet and wrinkled, making it difficult to maintain resistance to chemical irritation or physical irritation (i.e., the protective function against various skin irritation is reduced), and in cases where skin that is in a wet wrinkled state is converted to an alkaline condition by the ammonia components in excreted fluid such as urine (i.e., it undergoes chemical irritation), or abrasion and shifting force against the top sheet cause physical irritation, the skin may not be able to withstand such irritation, leading to such skin conditions as bedsores and rash (dermatitis). Since such a skin condition is more likely to occur when the wearer is lying face upward, it tends to occur near the gluteal region of the wearer (specifically, near the sacrum).

[00061 It is therefore a potential advantage of the present invention to provide an absorbent article that is unlikely to produce discomfort for the wearer, while also being unlikely to cause skin conditions such as bedsores or rash.

[SOLUTION TO PROBLEM]

[00071 One aspect (aspect 1) of the invention is an absorbent article comprising a top sheet and an absorbent body situated on a non-skin-facing surface side of the top sheet, and having a lengthwise direction, a widthwise direction and a thickness direction, wherein: the absorbent article has, in a plan view, an abdominal region, a dorsal region, and a crotch region located between these two regions, in the lengthwise direction, the absorbent article further comprises, in at least the dorsal region, a low friction member situated on a skin-facing surface side of the top sheet and having a plurality of openings penetrating the thickness direction, and a cover sheet situated on the skin-facing surface side of the low friction member, and each of the plurality of openings has an opening perimeter edge located on the skin facing surface side and a rib section protruding from the opening perimeter edge toward a non skin-facing surface side.

[00081 Since the absorbent article of aspect 1 comprises, in the dorsal region that corresponds to the gluteal region of the wearer that is susceptible to skin conditions such as bedsores and rash, a low friction member situated on the skin-facing surface side of the top sheet and a cover sheet that directly contacts with the skin of the wearer (specifically, the skin of the gluteal region), and friction resistance is reduced due to the low friction member provided between the cover sheet and top sheet, the cover sheet moves relatively easily with respect to the top sheet in the in-plane direction. Thus, even when the wearer has moved while wearing the absorbent article of aspect 1, the cover sheet can move in the in-plane direction together with the skin of the wearer to match movement of the wearer, so that physical irritation is unlikely to be produced on the skin of the wearer by abrasion or shifting. With the absorbent article of aspect 1, since the low friction member has rib sections that protrude from the opening perimeter edges toward the non-skin-facing surface side at each of the plurality of openings, the rib sections function as spacers between the low friction member and top sheet, allowing spaces to be formed between the low friction member and top sheet, as air channels to allow humidity from excreted fluid such as urine to be discharged. Thus, the absorbent article of aspect 1 makes excreted fluid such as urine and its resulting humidity, which have rewetted the skin-facing surface side, less likely to contact with the skin of the wearer, thus making the wearer less likely to sense a wetted state or musty state, or making the skin of the wearer unlikely to maintain a wetted state (i.e., a wet wrinkled state of the skin of the wearer). The absorbent article of aspect 1 is therefore less likely to create discomfort for the wearer and less likely to cause skin conditions such as bedsores and rash.

[0009] As used herein, the "excreted fluid" to be absorbed by the absorbent article is not particularly restricted so long as it can be absorbed and held in the absorbent body described below, and for example, it includes liquids such as urine, sweat and blood, and also low-viscosity matter such as soft feces.

[0010] Another aspect (aspect 2) of the invention is the absorbent article of aspect 1 wherein a

product of a height (hr) and thickness (tr) of the rib section is in a range of 2.0 x 10-3 mm to 5.0 X 10-3 m2

[0011] Since the rib sections of the absorbent article of aspect 2 have a specific structure such that the product of the height (hr) and thickness (tr) of the rib sections is in the range of 2.0 x 10 3 m2 to 5.0 x 10-3 m 2 , then even when force such as body pressure of the wearer is exerted in

the thickness direction of the absorbent article, the rib sections are less likely to collapse in the thickness direction, allowing the low-friction property of the low friction member (i.e., the state of low friction resistance between the cover sheet and the low friction member) to be maintained while more stably exhibiting the function as a spacer between the low friction member and the top sheet. As a result, since the absorbent article of aspect 2 is less likely to cause physical irritation by abrasion or shifting on the skin of the wearer, and is unlikely to allow rewetted excreted fluid such as urine or its humidity to contact again with the skin of the wearer, it can more stably exhibit the function and effect of being less likely to create discomfort for the wearer and less likely to cause skin conditions such as bedsores and rash.

[0012] Another aspect (aspect 3) of the invention is the absorbent article of aspect 1 or 2, wherein the opening perimeter edge has a skin-facing surface thereof curved toward the non skin-facing surface side.

[00131 Since the absorbent article of aspect 3 has the skin-facing surfaces of the opening perimeter edges of the openings of the low friction member curved toward the non-skin-facing surface side, it can firmly resist force applied in the in-plane direction, and even if the rib sections have collapsed in the thickness direction, the curved opening perimeter edges act as flat springs to readily restore the rib sections, so that as a result, it is possible to more reliably and continuously form the aforementioned spaces. In addition, curving of the skin-facing surfaces of the opening perimeter edges toward the non-skin-facing surface side makes it unlikely for the opening perimeter edges to catch onto the cover sheet (particularly the cover sheet that moves in the in-plane direction), and allows friction resistance between the cover sheet and low friction member to be further reduced. Therefore, the absorbent article of aspect 3 can even more reliably and continuously exhibit the function and effect of the absorbent article of aspect 1 or 2.

[0014] Another aspect (aspect 4) of the invention is the absorbent article of any one of aspects 1 to 3, wherein at the rib section, a rigidity of a tip section located on the non-skin-facing surface side is higher than a rigidity of the opening perimeter edge.

[0015] Since the absorbent article of aspect 4 has openings of the low friction member wherein the rigidity of the tip sections of the rib sections is higher than the rigidity of the opening perimeter edges, making the rib sections unlikely to deform, then even when force has been applied in the thickness direction or in-plane direction, it is possible to more reliably form the spaces between the low friction member and the top sheet.

[00161 Another aspect (aspect 5) of the invention is the absorbent article of any one of aspects 1 to 4, wherein at the rib section, a tip section located on the non-skin-facing surface side is situated in an interior of the top sheet.

[00171 Since the absorbent article of aspect 5 has a construction for the openings of the low friction member wherein the tip sections of the rib sections are situated on the interior of the top sheet (i.e., a construction in which the tip sections of the rib sections are embedded in the interior of the top sheet), the anchor effect of the construction makes the rib sections unlikely to move or deform, and the spaces can be more stably and reliably formed.

[00181 Another aspect (aspect 6) of the invention is the absorbent article of any one of aspects 1 to 5, wherein the top sheet has a protrusion-recess structure in which an elevated section protruding toward the skin-facing surface side in the thickness direction of the absorbent article and running continuously in a prescribed first direction, and a groove section depressed toward the non-skin-facing surface side in the thickness direction and running continuously in the first direction, are arranged alternately along a second direction that is perpendicular to the first direction.

[0019] Since the absorbent article of aspect 6 has a specific protrusion-recess structure in which the top sheet has elevated sections and groove sections, the elevated sections of the top sheet can function as spacers between the low friction member and top sheet, in addition to the rib sections of the low friction member, thus helping to more reliably ensure the aforementioned spaces. Moreover, since the top sheet of the absorbent article of aspect 6 has groove sections, whereby the low friction member and top sheet can be even further separated (i.e., an even larger cross-sectional area can be ensured in the thickness direction of the spaces), excreted fluid such as urine that has been absorbed into the absorbent body, and its resulting humidity, are unlikely to reach the skin-facing surface side of the low friction member (i.e., they are unlikely to contact with the skin of the wearer), and it is even less likely for the wearer to sense a wetted or musty state, or for the skin of the wearer to become wet.

[0020] Another aspect (aspect 7) of the invention is the absorbent article of aspect 6, wherein the rib section has a tip section thereof located on the non-skin-facing surface side overlapping with the elevated section in the thickness direction.

[0021] In the absorbent article of aspect 7, since the tip sections of the rib sections of the low friction member overlap with the elevated sections of the top sheet in the thickness direction, so that the low friction member and top sheet can be even further separated, excreted fluid such as urine that has been absorbed into the absorbent body, and its resulting humidity, are even less likely to reach the skin-facing surface side of the low friction member. Thus, the absorbent article of aspect 7 can more effectively and reliably exhibit the function and effect of the absorbent article of aspect 6.

[0022] Another aspect (aspect 8) of the invention is the absorbent article of aspect 6, wherein the rib section has a tip section thereof located on the non-skin-facing surface side overlapping with the groove section in the thickness direction.

[00231 In the absorbent article of aspect 8, since the tip sections of the rib sections of the low friction member overlap with the groove sections of the top sheet in the thickness direction, so that movement of the rib sections in the in-plane direction is restricted by the groove sections of the top sheet, it is possible to more stably and more reliably ensure the spaces formed between the low friction member and top sheet.

[0024] Another aspect (aspect 9) of the invention is the absorbent article of any one of aspects 1 to 8, wherein the absorbent article further comprises an absorbent sheet that includes a superabsorbent polymer, between the top sheet and the absorbent body, the absorbent sheet overlapping with the low friction member in the thickness direction.

[0025] Since the absorbent article of aspect 9 further comprises, between the top sheet and absorbent body, an absorbent sheet that includes a superabsorbent polymer, at a location overlapping with the low friction member in the thickness direction, and the absorbent sheet

(more specifically, the superabsorbent polymer included in the absorbent sheet) swells upon absorbing excreted fluid such as urine, the swelling of the absorbent sheet causes the top sheet to be pushed upward to the skin-facing surface side, so that it is easier to form a state in which the tip sections of the rib sections of the low friction member are embedded inside the top sheet. Thus, even after the absorbent article of aspect 9 has absorbed excreted fluid such as urine, the rib sections of the low friction member are unlikely to move or deform, and the spaces can be more stably and more reliably formed. In addition, since the absorbent article of aspect 9 comprises the absorbent sheet, it can exhibit more excellent absorption performance.

[00261 Another aspect (aspect 10) of the invention is the absorbent article of any one of aspects 1 to 9, wherein the absorbent body comprises an upper absorbing layer situated on the skin facing surface side and a lower absorbing layer situated on the non-skin-facing surface side, the upper absorbing layer having, in the crotch region, an upper layer groove extending in the lengthwise direction and penetrating the upper absorbing layer in the thickness direction, and in the upper layer groove, an angle formed between wall faces on one side edge and the other side edge in the widthwise direction and a virtual bottom side of the upper layer groove is more nearly perpendicular than an angle formed between wall faces of an abdominal side edge and a dorsal side edge in the lengthwise direction and the virtual bottom side of the upper layer groove.

[00271 Since the absorbent body of the absorbent article of aspect 10 comprises an upper absorbing layer and a lower absorbing layer and the upper absorbing layer has an upper layer groove with the aforementioned specific structure in the crotch region, excreted fluid such as urine that has been discharged by the wearer easily reaches the lower absorbing layer through the upper layer groove, and even if the excreted fluid temporarily pools in the upper layer groove, the excreted fluid can be preferentially diffused in the lengthwise direction. Thus, the absorbent article of aspect 10 can efficiently absorb excreted fluid such as urine over a wide area of the absorbent body while minimizing rewetting by excreted fluid that has been absorbed into the lower absorbing layer, by the presence of the upper absorbing layer, and therefore excreted fluid such as urine and its humidity are unlikely to contact the skin of the wearer, and it is possible to further prevent the wearer from sensing a state of wetness or mustiness and prevent the skin of the wearer from being in a wet state.

[00281 Another aspect (aspect 11) of the invention is the absorbent article of any of aspects I to 10, wherein the low friction member is formed of a resin sheet-like member including high density polyethylene at 50 mass% or greater.

[00291 Since the low friction member of the absorbent article of aspect 11 is formed by a resin sheet-like member including high-density polyethylene at 50 mass% or greater, the low friction member is a member with a fixed level of hardness and low friction resistance, and the rib sections formed in the low friction member are less likely to collapse in the thickness direction while the low-friction property of the low friction member can be ensured over a wide area. Thus, the absorbent article of aspect 11 can more stably exhibit the function of the rib sections as spacers between the low friction member and top sheet, and as a result, the skin of the wearer is unlikely to experience physical irritation by abrasion or shifting force, and rewetted excreted fluid such as urine, and its humidity, are even less likely to contact with the skin of the wearer.

[00301 Another aspect (aspect 12) of the invention is the absorbent article of aspect 11, wherein the resin sheet-like member includes the high-density polyethylene and low-density polyethylene in a mass ratio in a range of 50/50 to 75/25.

[00311 Since the resin sheet-like member forming the low friction member in the absorbent article of aspect 12 includes high-density polyethylene and low-density polyethylene in a mass ratio in the range of 50/50 to 75/25, stress that accumulates inside the sheet-like member during formation of the sheet-like member from the resin material or during formation of the openings of the sheet-like member (i.e., interior residual stress) can be reduced by the soft low-density polyethylene component, and rolling (i.e. curling) of the sheet-like member (particularly the widthwise end of the sheet-like member) by relaxation of interior residual stress can be minimized. Since the cover sheet can thus move more smoothly over the low friction member, it is possible to further minimize physical irritation to the skin of the wearer by abrasion or shifting force.

[0032] Another aspect (aspect 13) of the invention is the absorbent article according to any of aspects 1 to 12, wherein the top sheet and low friction member are joined at least partially via a low-tack adhesive having a measured value of0.78 N in a probe tack test.

[00331 Since the top sheet and low friction member of the absorbent article of aspect 13 are joined at least partially via a low-tack adhesive having a measured value of 0.78 N in a probe tack test, it is possible to prevent the low-tack adhesive from joining with the cover sheet situated on the skin-facing surface side through the openings of the low friction member, while anchoring the low friction member to the top sheet. Thus, the absorbent article of aspect 13 can minimize positional shifting and detachment of the low friction member while allowing more stable movement of the cover sheet.

[0034] Another aspect (aspect 14) of the invention is the absorbent article of any one of aspects 1 to 13, wherein the low friction member is formed by a sheet-like member in which both ends in the widthwise direction are displaced toward the skin-facing surface side.

[00351 Since the absorbent article of aspect 14 has both ends in the widthwise direction of the sheet-like member forming the low friction member displaced toward the skin-facing surface side, the ends that are displaced toward the skin-facing surface side press the cover sheet against the skin of the wearer, so that it is possible for the cover sheet to more precisely follow movement of the skin of the wearer.

[00361 Another aspect (aspect 15) of the invention is the absorbent article of any one of aspects 1 to 14, wherein the absorbent article has at least one folding line running in the widthwise direction, for folding of an expanded absorbent article in the lengthwise direction, and the low friction member is disposed at a location that does not overlap with the folding line, in the plan view.

[00371 Since the low friction member of the absorbent article of aspect 15 is disposed at a location that does not overlap with the folding line for folding of the absorbent article in the lengthwise direction, the low friction member does not form a crease running along the widthwise direction, and it is thus possible to ensure ease of movement of the cover sheet especially in the lengthwise direction, while the absorbent article can be stored in a lengthwise folded compact state in a package.

[ADVANTAGEOUS EFFECTS OF INVENTION]

[00381 According to the invention it is possible to provide an absorbent article that is less likely to produce discomfort for the wearer, while also being less likely to cause skin conditions such as bedsores or rash.

BRIEF DESCRIPTION OF DRAWINGS

[00391 FIG. 1 is a plan view of a urine-absorbing pad according to a first embodiment of the invention, as viewed in the thickness direction from the top sheet side, in the expanded state.

FIG. 2 is a cross-sectional view of a urine-absorbing pad according to the first embodiment of the invention, along line II-II in FIG. 1. FIG. 3 is a cross-sectional view of a urine-absorbing pad according to the first embodiment of the invention, along line III-III in FIG. 1. FIG. 4 is a main magnified cross-sectional view of the urine-absorbing pad shown in FIG. 2. FIG. 5 is a perspective view of a low friction member used in the urine-absorbing pad according to the first embodiment of the invention. FIG. 6 is a main magnified cross-sectional view of a modified example of the urine absorbing pad of the first embodiment of the invention. FIG. 7 is a plan view of a urine-absorbing pad according to a second embodiment of the invention, as viewed in the thickness direction from the top sheet side, in the expanded state. FIG. 8 is a main magnified cross-sectional view of the urine-absorbing pad of the second embodiment of the invention. FIG. 9 is a main magnified cross-sectional view of a modified example of the urine absorbing pad of the second embodiment of the invention. FIG. 10 is a plan view of a urine-absorbing pad according to a third embodiment of the invention, as viewed in the thickness direction from the top sheet side, in the expanded state. FIG. 11(a) is a main magnified cross-sectional view of the urine-absorbing pad according to the third embodiment of the invention, and FIG. 11(b) is a main magnified cross-sectional view showing the state of the urine-absorbing pad of the third embodiment of the invention in a state of having absorbed excreted fluid. FIG. 12 is a plan view of a urine-absorbing pad according to a fourth embodiment of the invention, as viewed in the thickness direction from the top sheet side, in the expanded state. FIG. 13 is a partial cross-sectional view of the urine-absorbing pad according to the fourth embodiment of the invention, along line XIII-XIII in FIG. 12. FIG. 14 is a partial cross-sectional view of the urine-absorbing pad according to the fourth embodiment of the invention, along line XIV-XIV in FIG. 12.

DESCRIPTION OF EMBODIMENTS

[0040] Preferred embodiments of the absorbent article of the invention will now be explained in greater detail with reference to the accompanying drawings. Throughout the present description, unless otherwise specified, the concept of "viewing an object (for example, an absorbent article, top sheet, absorbent body or low friction member) on the horizontal plane in the expanded state in the thickness direction of the object, from the upper side in the vertical direction (the top sheet side, when the object is an absorbent article)", will be referred to simply by the phrase "in the plan view".

[0041] The directions used throughout the present description are as follows, unless otherwise specified. Throughout the present description, the "lengthwise direction" is the "long direction of the lengths of a longitudinal object (for example, an absorbent article or absorbent body) in the plan view", the "widthwise direction" is the "short direction of the lengths of a longitudinal object in the plan view (short direction)", the "thickness direction" is the "vertical direction with respect to an object placed on the horizontal plane in the expanded state", with the lengthwise direction, widthwise direction and thickness direction being in a mutually perpendicular relationship. Throughout the present description, the "in-plane direction" is the "direction in which the plane of an approximately sheet-like object (such as an absorbent article, top sheet, absorbent body, low friction member or cover sheet) extends in the plan view (i.e., the horizontal plane direction)", the in-plane direction being in a mutually perpendicular relationship with the thickness direction. Also, throughout the present description, the concept of the "relatively proximal side in the lengthwise direction of a longitudinal object, with respect to the lengthwise center axis Cw located at the center in the lengthwise direction of the object and running in the widthwise direction" is referred to as the "inner side in the lengthwise direction", and the concept of the "relatively distal side in the lengthwise direction of a longitudinal object, with respect to the lengthwise center axis Cw" is referred to as the "outer side in the lengthwise direction". Similarly, the concept of the "relatively proximal side in the widthwise direction of a longitudinal object, with respect to the widthwise center axis CL located at the center in the widthwise direction of the object and running in the lengthwise direction" is referred to as the "inner side in the widthwise direction", and the concept of the "relatively distal side in the widthwise direction of a longitudinal object, with respect to the widthwise center axis CL" is referred to as the "outer side in the widthwise direction". Furthermore, throughout the present description, unless otherwise specified, the concept of the "relatively proximal side with respect to side of the wearer's skin when the absorbent article is worn" is referred to as the "skin-facing surface side", and the concept of the "relatively distal side with respect to the side of the wearer's skin when the absorbent article is worn" is referred to as the "non-skin-facing surface side", in the thickness direction of the absorbent article. The term "when worn" means the time from the point at which the wearer first wears the absorbent article (i.e., when a usable state is first formed), and throughout the period in which that state is maintained (while it is worn). Throughout the present description, the "surface on the skin-facing surface side" and the "surface on the non-skin-facing surface side" for each member composing the absorbent article (for example, the top sheet, absorbent body, low friction member and cover sheet) will be referred to simply as "skin-facing surface" and "non-skin-facing surface", respectively.

[0042] Fig. 1 is a plan view of a urine-absorbing pad 1 (absorbent article) according to afirst embodiment of the invention, as viewed in the thickness direction from the top sheet side, in the expanded state, and Fig. 2 and Fig. 3 are cross-sectional views of the urine-absorbing pad 1 along line II-II and line III-III, respectively, in Fig. 1. Fig. 4 is a main magnified cross-sectional view of the urine-absorbing pad 1 shown in Fig. 2, and Fig. 5 is a perspective view of the low friction member 14 used in the urine-absorbing pad 1.

[0043] As shown in Fig. 1, the urine-absorbing pad 1 according to the first embodiment of the invention, in the plan view, has a longitudinal outer shape with a lengthwise direction L and a widthwise direction W, and the approximate center section in the lengthwise direction L has an approximately hourglass shape constricted toward the inner side in the widthwise direction W. For the purpose of the invention, the outer shape of the absorbent article is not limited to the outer shape of this aspect, and so long as the shape is such that the length dimension in the lengthwise direction L is longer than the width dimension in the widthwise direction W, any longitudinal shape (for example, rectangular, elliptical or gourd-shaped) may be employed according to the particular purpose ofuse.

[0044] As shown in Fig. 1, the urine-absorbing pad 1 of the first embodiment has, in the lengthwise direction L in the plan view, an abdominal region 2 corresponding to the abdominal region (more specifically the lower abdomen) of the wearer when worn, a crotch region 3 corresponding to the crotch region (more specifically the middle crotch) of the wearer when worn, and a dorsal region 4 corresponding to the dorsal region (more specifically the gluteal region) of the wearer when worn, in that order.

[0045] As shown in Fig. 2 and Fig. 3, the urine-absorbing pad 1 comprises, as the basic construction in the thickness direction T, a liquid-permeable top sheet 5 situated on the skin facing surface side Si of the urine-absorbing pad 1, a liquid-absorbing absorbent body 6 situated on the non-skin-facing surface side S2 of the top sheet 5, a sheet-like low friction member 14 situated on the skin-facing surface side Si of the top sheet 5 in the dorsal region 4 and having a plurality of openings 16 penetrating the thickness direction T, and a cover sheet 13 situated on the skin-facing surface side Si of the low friction member 14, in the dorsal region 4. In addition, the urine-absorbing pad 1 of the first embodiment further comprises, as shown in Figs. I to 3, a pair of side sheets situated on the skin-facing surface side Si at both edges in the widthwise direction W of the urine-absorbing pad 1 (specifically, one side sheet 8 disposed at one side in the widthwise direction W and another side sheet 9 disposed at the other side in the widthwise direction W), a back sheet 7 situated on the non-skin-facing surface side S2 of the urine-absorbing pad 1, and a liquid-impermeable anti-leakage sheet 10 situated between the absorbent body 6 and the back sheet 7. As shown in Fig. 1 and Fig. 2, the pair of side sheets have the respective edge sections on the inner sides in the widthwise direction W of the urine absorbing pad 1 when worn (i.e., the inner side edge section 8R in the widthwise direction of the one side sheet 8 and the inner side edge section 9L in the widthwise direction of the other side sheet 9) standing up by contraction of elastic members 11 such as rubber thread, forming anti leakage wall sections 12 that serve to prevent leakage of excreted fluid such as urine.

[00461 Thus, the urine-absorbing pad 1 of the first embodiment comprises, in the dorsal region 4 that corresponds to the gluteal region of the wearer that is susceptible to skin conditions such as bedsores and rash, a low friction member 14 situated on the skin-facing surface side Si of the top sheet 5 and a cover sheet 13 that directly contacts with the skin of the wearer (specifically, the skin of the gluteal region), and since friction resistance is reduced due to the low friction member 14 between the cover sheet 13 and top sheet 5, the cover sheet 13 moves relatively easily with respect to the top sheet 5 in the in-plane direction. Thus, even when the wearer has moved while the urine-absorbing pad 1 is being worn, the cover sheet 13 can move in the in-plane direction together with the skin of the wearer to match movement of the wearer, so that physical irritation is unlikely to be produced on the skin of the wearer by abrasion or shifting force.

[00471 In addition, according to the first embodiment, the low friction member 14 has a plurality of openings 16 penetrating the thickness direction T, and as shown in Fig. 4 and Fig. 5, each of the plurality of openings 16 has an opening perimeter edge 17 situated relatively on the skin facing surface side Si, and rib sections 18 protruding from the opening perimeter edge 17 toward the non-skin-facing surface side S2.

[00481 With the urine-absorbing pad 1 of the first embodiment, since the low friction member 14 has rib sections 18 that protrude from the opening perimeter edges 17 toward the non-skin-facing surface side S2 at each of the plurality of openings 16, the rib sections 18 function as spacers between the low friction member 14 and top sheet 5, as shown in Fig. 4, allowing spaces Sp to be formed between the low friction member 14 and top sheet 5, as air channels to allow humidity from the excreted fluid such as urine to be discharged. Thus, the urine-absorbing pad 1 makes excreted fluid such as urine and its resulting humidity, which have rewetted the skin-facing surface side S1, less likely to contact with the skin of the wearer, thus making the wearer less likely to sense a wetted state or musty state, or making the skin of the wearer less likely to maintain a wetted state (i.e., a wet wrinkled state of the skin of the wearer). Therefore, the urine-absorbing pad 1 of the first embodiment is unlikely to create discomfort for the wearer and unlikely to cause skin conditions such as bedsores and rash.

[0049] Each of the members forming the absorbent article of the invention will now be explained in detail using the urine-absorbing pad 1 according to the embodiment described above.

[0050]

[Low friction member] In the urine-absorbing pad 1 of the first embodiment, as shown in Fig. 1, Fig. 2 and Fig. 4, the low friction member 14 is disposed between the top sheet 5 and cover sheet 13 in the dorsal region 4 of the urine-absorbing pad 1, and it is made of a low-friction sheet-like member that can reduce friction resistance with the cover sheet 13 situated on the skin-facing surface side Si.

[0051] In the plan view, the low friction member 14 has an essentially rectangular outer shape with a prescribed lengthwise length along the lengthwise direction L of the urine-absorbing pad 1 (for example, 100 mm to 200 mm), and a prescribed widthwise length along the widthwise direction W of the urine-absorbing pad 1 (for example, 50 mm to 150 mm). According to the invention, the outer shape (planar shape) of the low friction member is not limited to this aspect, and any outer shape (for example, circular, elliptical or polygonal) and size may be employed so long as it can reduce friction resistance with the cover sheet. The low friction member may be composed of a single sheet-like member as with the first embodiment, or it may be composed of multiple sheet-like members divided in the lengthwise direction and/or widthwise direction. In this case, the multiple sheet-like members composing the low friction member are disposed across prescribed intervals in the lengthwise direction and/or widthwise direction, as placement of multiple sheet-like members in this manner will help ensure liquid permeability and air permeability.

[0052] According to the invention, the sheet-like member that may be used as the low friction member is not particularly restricted so long as it can lower the friction resistance with the cover sheet, and it is possible to use a resin sheet-like member made of a resin or resin composition with a low frictional coefficient, e.g. an olefin-based resin such as polyethylene or polypropylene, a silicone resin or a fluorine resin such as polytetrafluoroethylene; or a covered sheet-like member comprising a material in which a low-friction material with a low frictional coefficient, such as a silicone resin or fluorine resin, covers at least one surface of a base sheet made of a general purpose thermoplastic resin or thermoplastic resin composition, e.g. an olefin based resin such as polyethylene or polypropylene or a polyester resin such as polyethylene terephthalate (the surface on the skin-facing surface side, within the absorbent article). Throughout the present description, "sheet-like member" and "base sheet" include the concept of any sheet-like structure in any desired form, such as a sheet or film having a thin, flat structure, as well as a sheet provided with an optional protrusion-recess structure; or a fiber sheet such as a woven fabric, nonwoven fabric or knitted fabric; or a laminated sheet comprising any combination of the foregoing.

[00531 When a resin sheet-like member is used as the low friction member, the resin sheet-like member preferably includes high-density polyethylene (HDPE) at 50 mass% or greater, and more preferably it includes high-density polyethylene (HDPE) and low-density polyethylene (LDPE) in a mass ratio in the range of 50/50 to 75/25. If the low friction member is formed by a resin sheet-like member including high-density polyethylene at 50 mass% or greater, the low friction member will be a member with a fixed level of hardness and low friction resistance due to the high-density polyethylene component, and therefore the rib sections of the openings formed in the low friction member will be less likely to collapse in the thickness direction while the low-friction property of the low friction member can be ensured over a wide area. Therefore, the absorbent article comprising such a resin sheet-like member as the low friction member can more stably exhibit the function of the rib sections as spacers between the low friction member and top sheet, and as a result, the skin of the wearer is unlikely to experience physical irritation by abrasion or shifting force and rewetted excreted fluid such as urine, and its humidity, are even less likely to contact with the skin of the wearer. Furthermore, if the resin sheet-like member forming the low friction member includes high-density polyethylene and low-density polyethylene in a mass ratio in the range of 50/50 to 75/25, stress that accumulates inside the sheet-like member during formation of the sheet-like member from the resin material or during formation of the openings of the sheet-like member (i.e., interior residual stress) can be reduced by the soft low-density polyethylene component, and therefore rolling (i.e. curling) of the sheet-like member (particularly the widthwise end of the sheet-like member) by relaxation of interior residual stress can be minimized. Consequently, in the absorbent article comprising such a resin sheet-like member as the low friction member, the cover sheet can move more smoothly over the low friction member, and it is possible to further minimize physical irritation to the skin of the wearer by abrasion or shifting force.

[0054] Throughout the present description, "high-density polyethylene" refers to polyethylene with a density of 0.942 g/cm3 or greater, and "low-density polyethylene" refers to polyethylene with a density of0.910 g/cm3 or greater and less than 0.930 g/cm 3

[0055] When the covered sheet-like member described above is used as the low friction member, the covered sheet-like member can be obtained by coating at least one surface of the base sheet made of a general purpose thermoplastic resin or thermoplastic resin composition with a prescribed amount of a low-friction material such as a silicone resin (for example, an amount in the range of about 0.6 g/m2 to 0.8 g/m2). When a silicone resin is used as the low-friction material, there are no particular restrictions on the form of the silicone resin which may be a solvent, solventless or emulsion form, while the cured form of the silicone resin is also not particularly restricted and a thermoset or ultraviolet cued silicone resin may be used. However, when a plastic film made of a general purpose thermoplastic resin or thermoplastic resin composition is used as the base sheet, it is preferred to use an ultraviolet curing silicone resin, because of the potential for deformation or melting of the base sheet when the silicone resin is cured by heating. The method of coating the low-friction material is not particularly restricted, and any coating method using a spray system, roll system, dip system or the like may be employed.

[00561 The structure of the low friction member is not particularly restricted so long as it has a low-friction property that can reduce friction resistance with the cover sheet situated on the skin facing surface side and so long as it has the openings described below, and any desired structure other than the aforementioned sheet-like member may be employed (for example, at least one elongated rod member, or at least one belt-shaped member), although a sheet-like member having an approximately flat structure overall as in the embodiment described above is preferred in consideration of allowing a low friction region to be ensured over a wide area, for easier sliding of the cover sheet on the surface of the low friction member (ease of movement in the in plane direction), and flexibility of the absorbent article as a whole.

[00571 The sheet-like member that may be used as a low friction member is not limited to one having an approximately flat structure overall as in the first embodiment described above, and for example, the sheet-like member may have both ends in the widthwise direction of the absorbent article warped (i.e., displaced) toward the skin-facing surface side. If both ends in the widthwise direction of the sheet-like member forming the low friction member are displaced toward the skin-facing surface side, then the ends that are displaced toward the skin-facing surface side will press the cover sheet situated on the skin-facing surface side of the low friction member against the skin of the wearer, making it possible for the cover sheet to more precisely follow movement of the skin of the wearer.

[00581 According to the invention, the static friction coefficient on the surface of the low friction member (at least the surface on the skin-facing surface side) is not particularly restricted so long as it can ensure a level of sliding allowing the cover sheet to move in the in-plane direction together with the skin of the wearer, matching movement of the wearer, and for example, it may be in the range of 0.04 to 0.80, preferably in the range of 0.10 to 0.50 and even more preferably in the range of 0.10 to 0.40. The dynamic friction coefficient on the surface of the low friction member is likewise not particularly restricted so long as it can ensure a level of sliding allowing the cover sheet to move in the in-plane direction together with the skin of the wearer, matching movement of the wearer, and for example, it may be in the range of 0.10 to 0.75, preferably in the range of 0.10 to 0.55 and even more preferably in the range of 0.10 to 0.45. The static friction coefficient and dynamic friction coefficient may be measured according to JIS P8147 (b), Horizontal plane method. The static friction coefficient and dynamic friction coefficient can be measured using a "#3 Union woven" (#3 shirting) cotton cloth for abrasion conforming to JIS L0803, as a test piece for a horizontal plate, using the low friction member as a weight test piece.

[0059] According to the invention, the low friction member may be disposed so as to completely overlap with the cover sheet in the thickness direction (i.e., so that the low friction member and the cover sheet have the same area in the plan view), or it may be disposed so that the low friction member envelops the cover sheet in the plan view; however, from the viewpoint of satisfactorily ensuring feel on the skin, liquid permeability and gas permeability, the low friction member is preferably disposed at a location overlapping with the cover sheet in the thickness direction, in a narrower region than the cover sheet. In this case, the low friction member preferably has the following fixed planar area so that the low friction member is not exposed even when the cover sheet has moved in the in-plane direction, the planar area of the low friction member being in the range of 10% to 80%, preferably in the range of 20% to 60% and even more preferably in the range of 25% to 50% of the planar area of the cover sheet.

[00601 The location in which the low friction member is disposed is not particularly restricted so long as it is a location overlapping with the cover sheet in the plan view; however, it is preferably at the approximate center of the cover sheet. The absorbent article of the invention also preferably has at least one folding line running in the widthwise direction, for folding of the expanded absorbent article in the lengthwise direction, in which case the low friction member is preferably disposed at a location that does not overlap with the folding line, in the plan view. For example, in the first embodiment described above, the urine-absorbing pad 1 has at least one folding line each, running in the widthwise direction W for folding of the expanded urine-absorbing pad 1 in the lengthwise direction L, at a location near the abdominal region side of the crotch region 3 and at a location near the abdominal region side of the dorsal region 4 (first folding line L i and second folding line L2 in Fig. 1), while the low friction member 14 is disposed at a location that does not overlap with the folding lines (specifically, a location in the dorsal region 4 further toward the dorsal region side than the second folding line L2). If the low friction member is disposed at a location that does not overlap with the folding lines, then a crease running along the widthwise direction will not be formed in the low friction member, so that it will be possible to ensure ease of movement of the cover sheet especially in the lengthwise direction, while the absorbent article can be stored in a lengthwise folded compact state in a package.

[00611 In the urine-absorbing pad 1 of the first embodiment, the low friction member 14 has a plurality of openings 16 penetrating the low friction member 14 in the thickness direction T, as shown in Fig. 2, Fig. 4 and Fig. 5. The plurality of openings 16 each have a roughly circular outer shape in the plan view, and are disposed in a zigzag fashion on the surface of the low friction member 14. In the absorbent article of the invention, the outer shape and manner of arrangement of the openings of the low friction member are not particularly restricted so long as the effect of the invention is not inhibited, and the openings may have any desired outer shapes other than circular (for example, line symmetrical shapes such as elliptical, quadrilateral or hexagonal shapes), and may be disposed in any desired arrangement such as a plurality of rows or a lattice form, in the plan view. Moreover, all of the plurality of openings may have the same outer shapes, or some of the openings may have different outer shapes, or all of the openings may have different outer shapes.

[0062] In addition, as shown in Fig. 4 and Fig. 5, each of the plurality of openings 16 of the low friction member 14 has an opening perimeter edge 17 which is the perimeter edge of the opening 16 that opens to the surface on the skin-facing surface side Si of the low friction member 14, and is delineated as the portion that has a smaller thickness than the thickness tb of the base 14b portion that is not the opening 16 of the low friction member 14 (the base 14b is the portion of the low friction member 14 with approximately constant thickness, the thickness being synonymous with "thickness of the low friction member") (in Fig. 4, this is the portion of the low friction member 14 surrounded by the dotted line), and rib sections 18 protruding from the opening perimeter edge 17 toward the non-skin-facing surface side S2, wherein the opening 16 has a tapered structure in the thickness direction T, the opening diameter (i.e., the diameter of the opening) decreasing from the skin-facing surface side Si toward the non-skin-facing surface side S2. The rib sections 18 contact with the surface of the skin-facing surface side Si of the top sheet 5 at the tip sections 18T.

[00631 In the urine-absorbing pad 1, the rib sections 18 have specific structures such that the product of the height (hr) and thickness (tr) of the rib sections is in the range of 2.0 x 10-3 m2 to 5.0 x 10-3 m2 As shown in Fig. 4, the protruding heights (hr) of the rib sections represent the distance (mm) in the vertical direction between a reference plane, the reference plane being the skin facing surface of the base 14b, as the portion other than the opening of the low friction member 14, and the tip sections 18T that are locations of the rib sections 18 that are furthest toward the non-skin-facing surface side S2, while the thickness (tr) of the rib sections represents the thickness (mm) at the portions of the rib sections 18 corresponding to 1/2 of the protruding heights (hr) of the rib sections (i.e., the portions where the distances from the reference plane or the tip sections 18T are 1/2 of the protruding heights (hr) of the rib sections in the vertical direction).

[0064] According to the invention, the protruding heights (hr) of the rib sections and the thicknesses (tr) of the rib sections formed at the openings of the low friction member are not particularly restricted so long as the effect of the invention is not inhibited, and for example, the protruding heights (hr) of the rib sections may be protruding heights in the range of 0.05 mm to 1.2 mm and preferably in the range of 0.1 mm to 0.5 mm, while the thicknesses (tr) of the rib sections may be thicknesses in the range of 0.001 mm to 0.1 mm and preferably in the range of 0.005 mm to 0.05 mm, and the rib sections preferably have a specific structure such that the 2 product of the height (hr) and thickness (tr) for the rib sections is in the range of 2.0 x 10-3mm to 5.0 x 10-3mm2 , as in the urine-absorbing pad1 described above, or more preferably they have a structure such that said product is in the range of 2.2 x 10-3 m 2 to 4.8 x 10-3mm2 .

If the rib sections formed in the openings of the low friction member have the structure specified above, then even when force such as body pressure of the wearer is exerted in the thickness direction of the absorbent article, the rib sections will be unlikely to collapse in the thickness direction, and it will be possible to maintain the low-friction property of the low friction member (i.e., the state of low friction resistance between the cover sheet and the low friction member) while more stably exhibiting their function as spacers between the low friction member and top sheet. As a result, since the absorbent article comprising a low friction member having rib sections with this specified structure is unlikely to cause physical irritation by abrasion or shifting on the skin of the wearer, and is unlikely to allow rewetted excreted fluid such as urine or its humidity to contact again with the skin of the wearer, it can more stably exhibit the function and effect of being less likely to create discomfort for the wearer and less likely to cause skin conditions such as bedsores and rash.

[00651 Incidentally, the thickness of the low friction member (i.e., the distance between the skin facing surface and the non-skin-facing surface at the bases, which are the portions of the low friction member other than the openings) is not particularly restricted so long as the effect of the invention is not inhibited, and any thickness (for example, a thickness in the range of 0.01 mm to 1.0 mm) may be employed in consideration of flexibility and strength.

[00661 Throughout the present description, the thickness of the low friction member, the protruding heights of the rib sections and the thicknesses of the rib sections may be those measured using any non-contact meter such as a laser displacement meter, or measured by magnified observation of a cross-section using a scanning electron microscope or the like. The thickness of the low friction member, the protruding heights of the rib sections and the thicknesses of the rib sections used are the average values from measurement at 5 different arbitrary locations, in consideration of the effect of measurement error.

[00671 For the first embodiment, as shown in Fig. 4, at the opening perimeter edge 17 of the opening 16, the skin-facing surface curves toward the non-skin-facing surface side S2 as it approaches the center of the open part of the opening 16, integrally connecting with the rib section 18. If the skin-facing surface of the opening perimeter edge 17 is thus curved toward the non-skin-facing surface side S2, then even when force is applied in the in-plane direction by movement of the wearer, the rib section 18 can firmly resist the in-plane direction force, and even if the rib section 18 has collapsed in the thickness direction T, the curved opening perimeter edge 17 acts as a flat spring to readily restore the rib section 18, so that as a result, it is possible to more reliably and continuously form the aforementioned space Sp. In addition, curving of the skin-facing surface of the opening perimeter edge 17 toward the non-skin-facing surface side S2 makes it unlikely for the opening perimeter edge 17 to catch onto the cover sheet 13 (particularly the cover sheet 13 that moves in the in-plane direction), and allows friction resistance between the cover sheet 13 and low friction member 14 to be further reduced.

[00681 According to the invention, the opening diameters (mm) of the openings of the low friction member are not particularly restricted so long as the effect of the invention is not inhibited, and for example, the opening diameter (di) at the opening perimeter edges may be in the range of 0.01 mm to 5.0 mm while the opening diameter (d2) at the ends of the rib sections may be in the range of 0.005 mm to 4.5 mm. As shown in Fig. 4, the opening diameter (di) of the opening perimeter edges is the opening diameter with the reference location being the boundary between the opening perimeter edge 17 and the portion other than the opening 16 (i.e., the base 14b), and specifically, it is the diameter of an inscribed circle in a plan view diagram drawn by the boundary line between the opening perimeter edge 17 and the base 14b (the maximum circle inscribed in the plan view diagram). Similarly, the opening diameter of the ends of the rib section is the diameter of an inscribed circle in a plan view diagram, drawn by the tip sections 18T of the rib sections 18, as shown in Fig. 4. The opening diameters can be measured by magnified observation of the surface or cross-section of the openings using any magnified observation means such as a microscope or scanning electron microscope.

[0069] For the first embodiment, the rib sections 18 of the openings 16 are formed simultaneously with the perforations (i.e., with formation of the opening perimeter edges), by drawing in the material for formation of the low friction member (for example, the resin sheet like member or base sheet), in its thickness direction, on a suction drum with a plurality of suction holes on its peripheral surfaces while heating, as described below, and therefore the rib sections 18 have lower thickness and relatively higher density in the thickness direction T toward the non-skin-facing surface side S2, as shown in Fig. 4. At the rib sections 18, therefore, the rigidity of the tip sections 18T located on the non-skin-facing surface side S2 is higher than the rigidity of the opening perimeter edges 17. If the rigidity of the tip sections 18T of the rib sections 18 is thus higher than the rigidity of the opening perimeter edges 17, it will be possible to ensure constant strength at the tip sections 18T that contact with the top sheet 5, and since the rib sections 18 are resistant to deformation, the spaces Sp can be more reliably formed between the low friction member 14 and the top sheet 5 even when force is applied in the thickness direction T or in-plane direction as mentioned above. According to the invention, the means for increasing the rigidity of the tip sections of the rib sections is not limited to increasing the density as described above, and the tip sections of the rib sections may have increased rigidity by employing a high-strength material or high-strength structure.

[00701 According to the invention, the means for forming the openings in the low friction member is not particularly restricted, and for example, the material for formation of the low friction member (for example, a resin sheet-like member or base sheet) may be drawn onto a suction drum having a plurality of suction holes on its peripheral surface, in the thickness direction while heating, and locations of the material for formation of the low friction member corresponding to the suction holes may be perforated by suction force of the suction drum; alternatively, an optional perforating processing apparatus or gear processing apparatus comprising roll-shaped or flat molding members comprising a plurality of holes or recesses having approximately the same diameters as the opening diameters of the opening perimeter edges, and a roll-shaped or flat molding member comprising a plurality of perforating protrusions (for example, needle-like protrusions) with diameters small enough to form the rib sections (i.e., approximately the same diameters as the opening diameters of the rib section tips), may be used to perforate the material for formation of the low friction member while clamping and pressing it between the molding members, in order to simultaneously form the opening perimeter edges and the rib sections. The protruding heights (hr) of the rib sections and the thicknesses (tr) of the rib sections can be formed to the prescribed ranges by adjusting the suction force or heating temperature of the suction drum, or alternatively by adjusting the interval between the inner peripheral surfaces of the holes of the molding member and the outer peripheral surfaces of the perforating protrusions. The openings may also be molded to the prescribed shapes by pressing the perimeter edges of the perforations by any molding method such as compression molding or vacuum forming, after the plurality of perforations have been formed in the material for formation of the low friction member using any desired perforation means, thus forming rib sections comprising the specified structure.

[00711 In the urine-absorbing pad 1 of the first embodiment, the rib sections 18 of the openings 16 are in contact with the skin-facing surface of the top sheet 5 at the tip sections 18T; however, the absorbent article of the invention is not limited to such an aspect. Fig. 6 is a main magnified cross-sectional view of a modified example of the urine-absorbing pad 1 of the first embodiment. In Fig. 6, the aspects of the construction other than the parts differing from the first embodiment are basically the same as the construction for the first embodiment, and therefore they will not be explained here. In the modified example shown in Fig. 6, in the rib sections 18 of the openings 16, the tip sections 18T located on the non-skin-facing surface side S2 are located inside the top sheet 5. Since the urine-absorbing pad 1 of the modified example has a construction for the openings 16 of the low friction member 14 wherein the tip sections 18T of the rib sections 18 are situated on the interior of the top sheet 5 (i.e., a construction in which the tip sections 18T of the rib sections

18 are embedded in the interior of the top sheet 5), the anchoring effect of the construction makes the rib sections 18 less likely to move or deform, and the spaces Sp can be more stably and reliably formed.

[0072] According to the invention, the low friction member is preferably joined with the top sheet by any joining means such as a hot-melt adhesive, and most preferably the tip sections of the rib sections of the openings are joined with the top sheet. The joining means may be applied continuously or intermittently in the lengthwise direction and/or widthwise direction of the absorbent article; however, applying the joining means intermittently will tend to ensure gas permeability and will tend to prevent mustiness in the absorbent article.

[00731 The top sheet and the low friction member are preferably joined at least partially by a low-tack adhesive having a measured value of no greater than 0.78 N in a probe tack test. If the top sheet and low friction member are joined at least partially by such a low-tack adhesive, it will be possible to prevent the low-tack adhesive from joining with the cover sheet situated on the skin-facing surface side through the openings of the low friction member, while anchoring the low friction member to the top sheet, and therefore positional shifting and detachment of the low friction member can be minimized while allowing more stable movement of the cover sheet. The measurement value in the probe tack test can be obtained using any probe tack-type test apparatus (for example, a Tacking Tester by Rhesca Corp.).

[0074]

[Cover sheet] The cover sheet to be used in the absorbent article of the invention will now be described. In the urine-absorbing pad 1 of the first embodiment, as shown in Fig. 1, Fig. 2 and Fig. 4, the cover sheet 13 is situated on the skin-facing surface side Si of the low friction member 14, overlapping with the low friction member 14 in the thickness direction T within the dorsal region 4 of the urine-absorbing pad 1, and it is disposed in a manner enveloping the entire low friction member 14 so that the low friction member 14 is not exposed in the plan view. Since the cover sheet 13 can move in the in-plane direction together with the skin of the wearer to match movement of the wearer, as mentioned above, it is possible to reduce the likelihood that physical irritation will be produced on the skin of the wearer by abrasion or shifting force.

[00751 In the plan view, the cover sheet 13 has an long, essentially rectangular outer shape in the lengthwise direction L, with a prescribed lengthwise length along the lengthwise direction L of the urine-absorbing pad 1, and a prescribed widthwise length along the widthwise direction W of the urine-absorbing pad 1. According to the invention, the outer shape of the cover sheet is not limited to this aspect, and any outer shape (for example, circular, elliptical or polygonal) may be employed so long as the entire low friction member can be covered.

[0076] In the urine-absorbing pad 1 of the first embodiment, as shown in Fig. 1 and Fig. 2, the cover sheet 13 has one side edge 13L in the widthwise direction W joined to the inner side portion 8S close to the inner side edge section 8R in the widthwise direction of the one side sheet 8, while also having the other side edge 13R in the widthwise direction W joined to the inner side portion 9S closer to the inner side edge section 9L in the widthwise direction of the other side sheet 9. Joining of the cover sheet 13 with each of the side sheets is carried out from each end of the cover sheet 13 in the lengthwise direction L across to its other end, as shown in Fig. 1, forming joining sections 15 running along the lengthwise direction L. For the first embodiment, the cover sheet 13 does not extend up to both edges in the widthwise direction W of the urine absorbing pad 1.

[00771 Thus, since the cover sheet 13 is joined to a pair of side sheets with a high degree of freedom of movement and in a manner capable of forming the anti-leakage wall sections 12, while not being directly anchored to the body portion of the urine-absorbing pad 1 (in this case, the body portion of the urine-absorbing pad 1 is the portion composed of the top sheet 5, absorbent body 6, anti-leakage sheet 10 and back sheet 7), movement of the cover sheet 13 is unlikely to be restricted by the body portion of the urine-absorbing pad 1, but rather, being joined to the side sheets which have a high degree of freedom, the cover sheet 13 moves relatively easily with respect to the body portion of the urine-absorbing pad 1. In addition, since the cover sheet 13 is joined to the pair of side sheets that can form anti leakage wall sections 12 when it is worn, each of the inner side edge sections in the widthwise direction of the pair of side sheets stand up when the urine-absorbing pad 1 is worn, so that the cover sheet 13 rises to the skin-facing surface side Si from the top sheet 5 or low friction member 14, and friction resistance is less likely to be produced between the cover sheet 13 and the low friction member 14, while force is also less likely to be exerted on the low friction member 14 in the thickness direction T. In the absorbent article of the invention, the cover sheet may also be directly anchored to the body portion of the absorbent article so long as its movement is not restricted. That is, the cover sheet may be joined to the body portion of the absorbent article (more specifically, the top sheet or back sheet) in a manner sufficiently bent to allow formation of a drape, so that its movement is not restricted.

[00781 The sizes of the joining sections 15 between the cover sheet 13 and each side sheet in the widthwise direction W are not particularly restricted so long as they allow joining with sufficient joining strength so that the cover sheet 13 does not detach when the urine-absorbing pad 1 is worn; however, they are preferably in the range of 5 to 30 mm, more preferably in the range of 10 to 25 mm, and even more preferably in the range of 15 to 20 mm. The method of joining the cover sheet with each of the side sheets is also not particularly restricted, and any joining method using a hot-melt adhesive, heat fusion or the like may be employed.

[00791 For the first embodiment, the cover sheet 13 is disposed only in the dorsal region 4 of the urine-absorbing pad 1 so as to correspond to the region near the gluteal region of the wearer (especially near the sacrum), which is more prone to skin conditions such as bedsores and rash; however, the absorbent article of the invention is not limited to such manner of arrangement, and the cover sheet may be disposed not only in the dorsal region but also in parts of the abdominal region or crotch region that are susceptible to the aforementioned skin conditions.

[00801 Moreover, for the first embodiment, the cover sheet 13 has the dorsal side edge 13B of the cover sheet 13 disposed in a manner extending to the dorsal side edge 1B of the urine absorbing pad 1, as shown in Fig. 1. While placing the cover sheet in this manner is not an essential constituent feature for the absorbent article of the invention, it is preferred for the cover sheet to extend to a location as close as possible to the dorsal side of the absorbent article. If the cover sheet extends to such a location, then it will be possible to cover a wider area near the gluteal region of the wearer that is prone to skin conditions, and such skin conditions will be less likely to occur.

[00811 The size of the cover sheet is not particularly restricted so long as it allows its function as a cover sheet to be exhibited, and the lengthwise length of the cover sheet may be, for example, in the range of 25% to 100%, preferably in the range of 30% to 80% and more preferably in the range of 40% to 70%, of the lengthwise length of the dorsal region 4. When the outer shape of the cover sheet is a shape other than rectangular, the "lengthwise length" is the maximum length in the lengthwise direction of the shape. The widthwise length of the cover sheet, on the other hand, may be, for example, in the range of 50 mm to 250 mm, preferably in the range of 80 mm to 200 mm and more preferably in the range of 100 mm to 180 mm, in consideration of the regions at locations that are susceptible to skin conditions, and tendency toward leakage of excreted fluid. When the outer shape of the cover sheet is a shape other than rectangular, the "widthwise length" is the maximum length in the widthwise direction of the shape.

[00821 According to the invention, the material forming the cover sheet is not particularly restricted, and any sheet-like member may be employed such as, for example, a nonwoven fabric such as an air-through nonwoven fabric or spunbond nonwoven fabric; a woven fabric; a knitted fabric; or a plastic film, with such sheet-like members being either hydrophilic or hydrophobic. Since the cover sheet to be used for the invention is able to directly contact with the skin of the wearer, the sheet-like member used is preferably a sheet-like member with excellent feel on the skin and flexibility. Examples of such sheet-like members include nonwoven fabrics such as air through nonwoven fabrics and spunbond nonwoven fabrics. The sheet-like member forming the cover sheet also preferably has excellent hydrophobicity, from the viewpoint of reducing wetting of the skin of the wearer (specifically, skin in the gluteal region). If a hydrophilic material is used as the sheet-like member forming the cover sheet, it will allow a constant amount of excreted fluid such as urine and its humidity to pass through, and is therefore advantageous in helping to reduce stagnation of excreted fluid such as urine or its humidity between the skin of the wearer and the cover sheet.

[00831 The cover sheet may also be formed of a sheet-like member that can be stretched in at least one direction. If the cover sheet is formed of such a sheet-like member that can be stretched in at least one direction, then when the gluteal region of the wearer has moved, the cover sheet will easily follow movement of the gluteal region of the wearer and will move more precisely with the gluteal region, thus making it possible to even further reduce the likelihood of physical irritation due to abrasion or shifting force on the gluteal region of the wearer. In addition, when the direction in which the cover sheet is able to stretch is parallel to the lengthwise direction of the absorbent article, then even when the gluteal region of the wearer has shifted forward while rising from the bed or during use of a wheelchair, the cover sheet will be able to accurately move together with the gluteal region, making it possible to more reliably minimize physical irritation caused by abrasion or shifting force, and as a result, skin conditions such as bedsores and rash can be more reliably reduced.

[0084] The sheet-like member that can stretch in at least one direction is not particularly restricted so long as it is stretchable in at least one direction, and for example, it is possible to use a nonwoven fabric or a woven or knitted fabric containing elastic fibers; a nonwoven fabric having a surface with alternating ridges and grooves formed in it (i.e., a nonwoven fabric having a ridge-groove structure); a gear stretched nonwoven fabric; or a nonwoven fabric or a woven or knitted fabric bearing an elastic member; or a laminated body comprising a combination of any of these. Of these, a nonwoven fabric having a ridge-groove structure is particularly preferred for the cover sheet as it is stretchable in the direction perpendicular to the direction in which the ridges and grooves run, and such a nonwoven fabric is not only stretchable but also has lower contact area with the skin of the wearer and produces low physical irritation on skin.

[00851

[Side sheets] The pair of side sheets to be used in the absorbent article of the invention will now be described. In the urine-absorbing pad 1 of the first embodiment, as shown in Figs. 1 to 3, the pair of side sheets are composed of one side sheet 8 that is belt-shaped and situated on one side of the urine-absorbing pad 1 in the widthwise direction W, and another side sheet 9 that is belt-shaped and situated on the other side of the urine-absorbing pad 1 in the widthwise direction W, on the skin-facing surface side Si of the top sheet 5. As shown in Fig. 1, the one side sheet 8 and other side sheet 9 extend from the abdominal side edge 1A in the lengthwise direction L of the urine absorbing pad 1 across to the dorsal side edge 1B, in the plan view, and as shown in Fig. 2, the widthwise outer side edge section 8L of the one side sheet 8 and the widthwise outer side edge section 9R of the other side sheet 9, located on the outer sides in the widthwise direction W, are joined with the one side edge and other side edge, respectively, in the widthwise direction W of the anti-leakage sheet 10, forming anchored edges, while the widthwise inner side edge section 8R of the one side sheet 8 and the widthwise inner side edge section 9L of the other side sheet 9, located on the inner sides in the widthwise direction W, are not joined with any member, forming free edges.

[00861 Since the anti-leakage sheet is not an essential constituent feature of the absorbent article of the invention, as explained below, in cases when the absorbent article does not comprise an anti-leakage sheet, the pair of side sheets may be joined with the one side edge (the one side edge 7L of the first embodiment) and the other side edge (the other side edge 7R of the first embodiment), respectively, of the back sheet in the widthwise direction.

[00871 For the first embodiment, as shown in Fig. 1 and Fig. 3, the one side sheet 8 and the other side sheet 9 have, near the widthwise inner side edge section 8R and near the widthwise inner side edge section 9L, elastic members 11 disposed along their lengthwise direction L, so that the one side sheet 8 and the other side sheet 9 contract in the lengthwise direction L and stand up at their respective widthwise inner side edge sections. Contraction of the elastic members 11 causes the respective widthwise inner side edge sections of the one side sheet 8 and the other side sheet 9 to stand up, forming anti-leakage wall sections 12 that serve to prevent leakage of excreted fluid such as urine in the widthwise direction.

[00881

For the first embodiment, as shown in Fig. 1, the elastic members 11 are disposed straddling a wide region from the abdominal region 2 across the dorsal region 4, in the lengthwise direction L of the urine-absorbing pad 1; however, the manner of arrangement of the elastic members is not particularly restricted for the invention. For example, the elastic members may be disposed along the full lengths of the pair of side sheets in the lengthwise direction, or they may be disposed within a prescribed range excluding the regions near the front side edge and near the back side edge in the lengthwise direction of the pair of side sheets, as in the embodiment described above. Arranging the elastic members in the latter way is advantageous in that the ends in the lengthwise direction of the absorbent article will be less likely to warp.

[00891 The stretch factor when the elastic members are attached to the pair of side sheets is not particularly restricted so long as it is a factor that does not overly stretch the cover sheet and makes leakage of excreted fluid unlikely, such a stretch factor being, for example, in the range of 1.3 to 3.0, preferably in the range of 1.5 to 2.5 and more preferably in the range of 1.7 to 2.3, with respect to the natural length of the elastic members. For the first embodiment, the elastic members 11 are placed with one each in the widthwise inner side edge section 8R of the one side sheet 8 and the widthwise inner side edge section 9L of the other side sheet 9; however, there is no limitation to this arrangement for the invention, and the elastic members may be placed with two or more for each of the pair of side sheets. The elastic members used may be rubber threads commonly used in absorbent articles such as urine-absorbing pads or disposable diapers.

[0090] For the first embodiment, as shown in Fig. 1, the pair of side sheets (the one side sheet 8 and other side sheet 9) are constructed of liquid-impermeable sheets having longitudinal belt shaped outer shapes that are long in the direction along the lengthwise direction L of the urine absorbing pad 1; however, the pair of side sheets are not limited to this aspect for the invention, and liquid-impermeable sheets of any desired outer shape and size may be used so long as they are able to form the prescribed anti-leakage wall sections.

[0091] The belt-shaped liquid-impermeable sheets that may be used as side sheets are not particularly restricted so long as they have the prescribed liquid impermeability and flexibility, and for example, any liquid-impermeable sheets may be used such as hydrophobic nonwoven fabrics (for example, hydrophobic or hydrophobicity-imparted spunbond nonwoven fabrics, point bond nonwoven fabrics, or spunbond layer/meltblown layer/spunbond layer (SMS) nonwoven fabrics), liquid-impermeable synthetic resin films, or laminates of these.

[0092] The basis weight and thickness of a belt-shaped liquid-impermeable sheet (for example, a hydrophobic nonwoven fabric or the like) to be used as a side sheet are not particularly restricted so long as the effect of the invention is not inhibited, and any basis weight and thickness may be used in consideration of liquid impermeability and flexibility.

[00931 Although providing such side sheets is not an essential constituent feature for the absorbent article of the invention, if the absorbent article comprises such side sheets then an advantage will be provided since it will be possible to effectively minimize leakage of excreted fluid such as urine in the widthwise direction of the absorbent article, while less friction resistance will tend to be produced between the cover sheet and the low friction member when the cover sheet is joined, as mentioned above, and force will be less likely to be exerted on the low friction member in the thickness direction.

[0094]

[Top sheet] The top sheet to be used in the absorbent article of the invention will now be described. In the urine-absorbing pad 1 of the first embodiment, as shown in Figs. I to 3, the top sheet 5 is disposed at a location that can directly contact with the skin of the wearer (i.e., a location on the skin-facing surface side Si of the urine-absorbing pad 1), except for the portion overlapping with the cover sheet 13 and low friction member 14 in the thickness direction T, and it is composed of a liquid-permeable sheet that allows permeation of excreted fluid discharged by the wearer.

[0095] As shown in Figs. 1 to 3, the top sheet 5 extends in the lengthwise direction L and widthwise direction W so as to cover approximately the entire absorbent body 6 situated on the non-skin-facing surface side S2 of the top sheet 5, in the plan view, and it has an essentially longitudinal rectangular outer shape that is long in the direction along the lengthwise direction L of the urine-absorbing pad 1. For the absorbent article of the invention, the outer shape of the top sheet is not limited to such an aspect, and so long as the skin-facing surface of the absorbent body disposed on the non-skin-facing surface side of the top sheet is not exposed in at least the crotch region, any outer shape or size may be employed according to the particular purpose of use.

[00961 Liquid-permeable sheets that may be used as the top sheet are not particularly restricted so long as they have the prescribed liquid permeability and feel on the skin, and any nonwoven fabric may be used such as, for example, spunbond nonwoven fabrics, air-through nonwoven fabrics or SMS nonwoven fabrics formed using cellulosic fibers or hydrophilicized thermoplastic resin fibers.

[00971

The structure of the top sheet in the absorbent article of the invention is not particularly restricted so long as it has the prescribed liquid permeability and feel on the skin, and it may have an approximately flat structure such as the top sheet 5 of the first embodiment, or a prescribed protrusion-recess structure such as the top sheet of the second embodiment described below; however, from the viewpoint of allowing the effect of the invention to be exhibited more advantageously, the top sheet used is preferably one having a prescribed protrusion-recess structure such as the top sheet of the second embodiment described below.

[00981 The basis weight and thickness of a liquid-permeable sheet (nonwoven fabric or the like) that may be used as the top sheet are not particularly restricted so long as the effect of the invention is not inhibited, and any basis weight and thickness may be used in consideration of liquid permeability and feel on the skin, although from the viewpoint of helping to prevent rewetting of excreted fluid, the top sheet used is preferably a liquid-permeable sheet having a relatively high thickness.

[0099] The top sheet may be joined at the non-skin-facing surfaces of the pair of side sheets, or it may be joined at the skin-facing surface or non-skin-facing surface of the absorbent body, or it may be joined at the skin-facing surface of the anti-leakage sheet or back sheet. The joining method is also not particularly restricted, and any desired joining means may be employed, such as a hot-melt adhesive or heat fusion.

[0100]

[Absorbent body] The absorbent body to be used in the absorbent article of the invention will now be described. As shown in Figs. 1 to 3, the absorbent body 6 in the urine-absorbing pad 1 of the first embodiment is composed of an absorbing member situated between the top sheet 5 and the back sheet 7 (more specifically, the anti-leakage sheet 10) in the thickness direction T of the urine absorbing pad 1, and it absorbs and retains excreted fluid of the wearer that has permeated the top sheet 5.

[0101] As shown in Fig. 1, in the plan view, the absorbent body 6 extends from the abdominal region 2 of the urine-absorbing pad 1 (specifically, near the abdominal side edge 1A in the lengthwise direction L) across to the dorsal region 4 (specifically, near the dorsal side edge 1B in the lengthwise direction L), while also extending from near one side edge in the widthwise direction W across to near the other side edge in the widthwise direction W of the urine absorbing pad 1, being formed long in the direction along the lengthwise direction L of the urine absorbing pad 1 while having an approximately hourglass-shaped outer shape whose center section in the lengthwise direction is constricted toward the inner side in the widthwise direction. According to the invention, the outer shape of the absorbent body (absorbing member) is not limited to this aspect, and it may have any desired outer shape such as a rectangular or oblong so long as it can exhibit the prescribed absorption performance.

[0102] Furthermore, the location where the absorbent body is disposed, in the plan view, is also not particularly restricted so long as it is a location including the center section of the absorbent article, that also includes the intersection between the widthwise center axis CL running in the lengthwise direction L and the lengthwise center axis Cw running in the widthwise direction W, and the absorbent body may be disposed in a manner shifted toward one direction in the lengthwise direction of the absorbent article.

[01031 According to the invention, the absorbing member to be used as the absorbent body is not particularly restricted so long as it can absorb and retain excreted fluid such as urine, and any absorbing member known in the field may be used. Examples of such absorbing members include those having an absorbent core formed of an absorbent material, covered with a hydrophilic core wrap sheet such as a tissue. The absorbent material composing the absorbent core may be, for example, hydrophilic fibers or a superabsorbent polymer, and specifically, cellulosic fibers such as ground pulp, cotton, rayon or acetate; granules composed of a superabsorbent polymer such as sodium acrylate copolymer; or mixtures comprising any desired combinations of these.

[0104] According to the invention, the absorbent body may be composed of an absorbent body with a multilayer structure having two or more absorbing layers laminated in the thickness direction, as in the embodiment described below. In this case, each of the absorbing layers may be formed of the aforementioned absorbing member. An absorbent body with a multilayer structure will also be explained in detail for a different embodiment of the invention, described below.

[0105] The basis weight and thickness of an absorbing member that may be used as the absorbent body are not particularly restricted so long as the effect of the invention is not inhibited, and any basis weight and thickness may be used in consideration of the absorption property and flexibility.

[01061

[Back sheet] The back sheet to be used in the absorbent article of the invention will now be described.

In the urine-absorbing pad 1 of the first embodiment, as shown in Figs. I to 3, the back sheet 7 is disposed at a location on the non-skin-facing surface side S2 of the urine-absorbing pad 1 in the thickness direction T, and it is composed of a hydrophobic nonwoven fabric or liquid impermeable sheet that prevents permeation of excreted fluid such as urine that has been discharged from the wearer while still exhibiting the prescribed air permeability, functioning to prevent leakage of the excreted fluid to the outside (for example, the clothing of the wearer).

[01071 As shown in Figs. 1 to 3, in the plan view, the back sheet 7 extends from the abdominal side edge 1A across to the dorsal side edge 1B in the lengthwise direction L of the urine absorbing pad 1, and extends from the one side edge across to the other side edge in the widthwise direction W of the urine-absorbing pad 1, having an approximately hourglass-shaped outer shape similar to the outer shape of the urine-absorbing pad 1. According to the invention, the outer shape of the back sheet is not limited to such an aspect, and so long as the non-skin facing surface of the absorbent body disposed on the skin-facing surface side of the back sheet is not exposed, any outer shape or size may be employed according to the particular purpose ofuse.

[01081 According to the invention, hydrophobic nonwoven fabrics that may be used for the back sheet are not particularly restricted so long as they have the prescribed hydrophobicity and air permeability, and any hydrophobic nonwoven fabric may be used such as, for example, a spunbond nonwoven fabric, point bond nonwoven fabric, meltblown nonwoven fabric, SMS nonwoven fabric (a nonwoven fabric comprising a multilayer structure of three or more layers (for example, a 5-layer structure) that includes nonwoven fabric layers in an arrangement of spunbond layer/meltblown layer/spunbond layer) or an air-through nonwoven fabric. Such a hydrophobic nonwoven fabric does not need to be liquid-impermeable when the absorbent article comprises an anti-leakage sheet between the back sheet and the absorbent body; however, it is preferably one that is liquid-impermeable in cases where the absorbent article does not comprise an anti-leakage sheet between the back sheet and the absorbent body.

[0109] The constituent fibers of the hydrophobic nonwoven fabric are not particularly restricted, and for example, polyolefin-based fibers such as polyethylene or polypropylene; polyester-based fibers such as polyethylene terephthalate; and thermoplastic resin fibers such as various types of composite fibers including core-sheath composite fibers may be used. Moreover, the basis weight and thickness of the hydrophobic nonwoven fabric are not particularly restricted so long as the effect of the invention is not inhibited, and any basis weight and thickness may be used in consideration of air permeability.

[0110]

A liquid-impermeable sheet that may be used as the back sheet, on the other hand, is not particularly restricted so long as it has the prescribed liquid impermeability, and any liquid impermeable sheet may be used, such as a plastic film made of a thermoplastic resin such as polyethylene. The liquid-impermeable sheet used is preferably one having liquid impermeability and also the prescribed air permeability (for example, a plastic film with multiple open pores).

[0111] Also, for the first embodiment described above, the urine-absorbing pad 1 comprises a liquid-impermeable anti-leakage sheet 10 between the back sheet 7 and the absorbent body 6. Such an anti-leakage sheet 10 is composed of a plastic film made of a thermoplastic resin such as polyethylene, and it functions to prevent permeation of excreted fluid such as urine that has been discharged from the wearer and to avoid leakage of the excreted fluid to the outside. Providing such an anti-leakage sheet is not a necessary constituent feature for the absorbent article of the invention; however, when an absorbent article is provided with an anti-leakage sheet it will be possible to more effectively reduce leakage of excreted fluid such as urine.

[0112] According to the invention, the location in which the anti-leakage sheet is placed is not particularly restricted so long as it is a region allowing the function of the anti-leakage sheet to be exhibited, and the anti-leakage sheet may be disposed from the abdominal region across to the dorsal region of the absorbent article, as in the first embodiment described above, or it may be disposed only in a specific region such as the crotch region.

[01131 Another embodiment (second embodiment) of the present invention will now be explained with reference to the accompanying drawings, this embodiment differing from the first embodiment only in the structure of the top sheet. The aspects of the construction other than the parts differing from the first embodiment are basically the same as the first embodiment, and therefore they will not be explained here.

[0114] Fig. 7 is a plan view of a urine-absorbing pad 1 according to the second embodiment of the invention, as viewed in the thickness direction T from the top sheet 5 side, in the expanded state, and Fig. 8 is a main magnified cross-sectional view of the urine-absorbing pad 1 of the second embodiment. As shown in Fig. 7 and Fig. 8, in the urine-absorbing pad 1 of the second embodiment of the invention, the top sheet 5 has a protrusion-recess structure 19 wherein elevated sections 19A that are protruding toward the skin-facing surface side Si in the thickness direction T of the urine-absorbing pad 1 and run continuously in the direction along the lengthwise direction L of the urine-absorbing pad 1, and groove sections 19B that are depressed toward the non-skin-facing surface side S2 in the thickness direction T of the urine-absorbing pad 1 and run continuously in the direction along the lengthwise direction L of the urine absorbing pad 1, are arranged alternately along the widthwise direction W of the urine-absorbing pad 1.

[0115] Since the urine-absorbing pad 1 of the second embodiment has a specific protrusion recess structure 19 in which the top sheet 5 has elevated sections 19A and groove sections 19B, the elevated sections 19A of the top sheet 5 can also function as spacers between the low friction member 14 and top sheet 5, in addition to the rib sections 18 of the low friction member 14, thus helping to more reliably ensure the aforementioned spaces Sp. Moreover, since the top sheet 5 in the urine-absorbing pad 1 of the second embodiment has groove sections 19B, whereby the low friction member 14 and top sheet 5 can be even further separated (i.e., an even larger cross sectional area can be ensured in the thickness direction T of the spaces Sp), excreted fluid that has been absorbed into the absorbent body 6, and its resulting humidity, are unlikely to reach the skin-facing surface side Si of the low friction member 14, and it is even less likely for the wearer to sense a wetted or musty state, or for the skin of the wearer to become wet.

[01161 In the absorbent article of the invention, the direction in which the elevated sections and groove sections of the top sheet run is not limited to the manner of the second embodiment, and the elevated sections and groove sections may run along any other desired direction, such as the widthwise direction of the absorbent article.

[01171 Moreover, in the urine-absorbing pad 1 of the second embodiment, as shown in Fig. 8, the low friction member 14 is disposed so that the tip sections 18T of the rib sections 18 located on the non-skin-facing surface side S2 overlap with the elevated sections 19A of the top sheet 5 in the thickness direction T of the urine-absorbing pad 1. If the tip sections 18T of the rib sections 18 of the low friction member 14 thus overlap with the elevated sections 19A of the top sheet 5 in the thickness direction T, the low friction member 14 and top sheet 5 can be even further separated, and excreted fluid such as urine that has been absorbed into the absorbent body 6, and its resulting humidity, are even less likely to reach the skin-facing surface side Si of the low friction member 14. This will allow the urine-absorbing pad 1 of the second embodiment to more effectively and reliably exhibit the aforementioned function and effect (i.e., the function and effect of making it even less likely that the wearer will sense a wetted or musty state or that the skin of the wearer will become wetted).

[01181 In the urine-absorbing pad 1 of the second embodiment, the low friction member 14 is disposed so that the tip sections 18T of the rib sections 18 located on the non-skin-facing surface side S2 overlap with the elevated sections 19A of the top sheet 5 in the thickness direction T of the urine-absorbing pad 1; however, the manner of arrangement of the low friction member in the absorbent article of the invention is not limited to this form. Fig. 9 is a main magnified cross sectional view of a modified example of the urine-absorbing pad 1 of the second embodiment of the invention. In Fig. 9, the aspects of the construction other than the parts differing from the second embodiment are basically the same as the second embodiment, and therefore they will not be explained here.

[0119] In the modified example shown in Fig. 9, the low friction member 14 is disposed so that the tip sections 18T of the rib sections 18 located on the non-skin-facing surface side S2 overlap with the groove sections 19B of the top sheet 5 in the thickness direction T of the urine absorbing pad 1, as shown in Fig. 9. If the tip sections 18T of the rib sections 18 of the low friction member 14 thus overlap with the groove sections 19B of the top sheet 5 in the thickness direction T, movement of the rib sections 18 in the in-plane direction can be restricted by the groove sections 19B of the top sheet 5, thus making it possible to more stably and more reliably ensure the spaces Sp formed between the low friction member 14 and top sheet 5.

[0120] So long as the protrusion-recess structure of the top sheet of the invention is a protrusion recess structure in which elevated sections protruding toward the skin-facing surface side in the thickness direction of the absorbent article and running continuously in a prescribed first direction, and groove sections depressed toward the non-skin-facing surface side in the thickness direction and running continuously in the first direction, are arranged alternately along a second direction that is perpendicular to the first direction, then the structure on the non-skin-facing surface side is not particularly restricted, and it may be approximately flat as in the second embodiment, or groove sections and elevated sections may be formed corresponding to the elevated sections and groove sections (i.e., it may be formed so that the cross-sectional structure is essentially undulating along the second direction of the top sheet).

[0121] The method for providing a protrusion-recess structure to the top sheet is not particularly restricted, and examples include a method of continuously blasting gas (for example, air) onto a fiber web, or any desired shaping method such as compression molding or gear stretching.

[0122] Another embodiment (third embodiment) of the invention will now be explained with reference to the accompanying drawings, this embodiment differing from thefirst embodiment only in being provided with an absorbent sheet. The aspects of the construction other than the parts differing from the first embodiment are basically the same as the first embodiment, and therefore they will not be explained here.

[01231 Fig. 10 is a plan view of the urine-absorbing pad 1 of the third embodiment of the invention as seen from the top sheet 5 side in the thickness direction T, in the expanded state, Fig. 11(a) is a main magnified cross-sectional view of the urine-absorbing pad 1 of the third embodiment, and Fig. 11(b) is a main magnified cross-sectional view showing the urine absorbing pad 1 of the third embodiment in a state of having absorbed excreted fluid. As shown in Fig. 10 and Fig. 11(a), the urine-absorbing pad 1 of the third embodiment of the invention further comprises an absorbent sheet 20 including a superabsorbent polymer, between the top sheet 5 and the absorbent body 6.

[0124] As shown in Fig. 10, the absorbent sheet 20 has, in the plan view, an essentially rectangular outer shape that is long in the lengthwise direction L, having a prescribed lengthwise length (for example, 100 mm to 200 mm) extending from the crotch region 3 across to the dorsal region 4 of the urine-absorbing pad 1, and a prescribed widthwise length (for example, 100 mm to 200 mm) extending so as to cover most of the absorbent body 6 in the widthwise direction W. The outer shape of the absorbent sheet in the absorbent article of the invention is not limited to this aspect, and any desired outer shape (for example, circular, elliptical or polygonal) may be employed, depending on the desired absorption performance.

[0125] As shown in Fig. 10 and Fig. 11(a), the absorbent sheet 20 in the urine-absorbing pad 1 of the third embodiment is disposed in the plan view so as to extend from the crotch region 3 across to the dorsal region 4 of the urine-absorbing pad 1, and so that it overlaps with the low friction member 14 in the thickness direction T, within the dorsal region 4. If the absorbent sheet 20 is disposed in a manner overlapping with the low friction member 14 in the thickness direction T, then the absorbent sheet 20 (more specifically, the superabsorbent polymer included in the absorbent sheet 20) will swell upon absorbing excreted fluid such as urine, the swelling of the absorbent sheet 20 causing the top sheet 5 to be pushed upward to the skin-facing surface side Si, so that it will be easier to form a state in which the tip sections 18T of the rib sections 18 of the low friction member 14 are embedded inside the top sheet 5, as shown in Fig. 11(b). Thus, even after the urine-absorbing pad 1 of the third embodiment has absorbed excreted fluid such as urine, the rib sections 18 of the low friction member 14 are unlikely to move or deform, and the spaces Sp can be more stably and more reliably formed. Since the urine-absorbing pad 1 of the third embodiment comprises the absorbent sheet 20, it can exhibit more excellent absorption performance.

[01261

According to the invention, the absorbent sheet is not particularly restricted so long as it is a sheet-like member including a superabsorbent polymer, and for example, a superabsorbent polymer such as a sodium acrylate copolymer may be covered with a hydrophilic cover sheet such as a tissue. In addition to a superabsorbent polymer, the absorbent sheet may also include an absorbent material as in the absorbent body described above.

[01271 The basis weight and thickness of the absorbent sheet are not particularly restricted so long as the effect of the invention is not inhibited, and any basis weight and thickness may be used in consideration of the desired absorption performance and flexibility.

[01281 A fourth embodiment, as yet another embodiment of the invention, will now be explained with reference to the accompanying drawings, this embodiment differing from the first embodiment only in the construction of the absorbent body. The aspects of the construction other than the parts differing from the first embodiment are basically the same as the first embodiment, and therefore they will not be explained here.

[0129] Fig. 12 is a plan view of a urine-absorbing pad 1 according to the fourth embodiment of the invention, as viewed in the thickness direction T from the top sheet 5 side, in the expanded state, Fig. 13 is a partial cross-sectional view, as a cross-section of the urine-absorbing pad 1 of the fourth embodiment along lines XIII-XIII in Fig. 12, and Fig. 14 is a partial cross-sectional view, as a cross-section of the urine-absorbing pad 1 of the fourth embodiment along line XIV XIV of Fig. 12. As shown in Figs. 12 to 14, the absorbent body 6 of the urine-absorbing pad 1 of the fourth embodiment of the invention comprises an upper absorbing layer 61 situated on the skin facing surface side Si and a lower absorbing layer 62 situated on the non-skin-facing surface side S2, in the thickness direction T. In the plan view, the upper absorbing layer 61 is formed long in the direction along the lengthwise direction L of the urine-absorbing pad 1, with the crotch region 3 having an approximately hourglass-shaped outer shape that is constricted toward the inner side in the widthwise direction, while the lower absorbing layer 62 is formed long in the direction along the lengthwise direction L of the urine-absorbing pad 1, in the plan view, and has an essentially rectangular outer shape with a smaller widthwise length than the minimum widthwise length of the upper absorbing layer 61.

[01301 The upper absorbing layer 61 has an upper layer groove 61S extending along the lengthwise direction L in the crotch region 3 and penetrating the upper absorbing layer 61 in the thickness direction T. As shown in Fig. 12, the upper layer groove 61S is situated in the crotch region 3 of the urine-absorbing pad 1, while extending in the lengthwise direction L through the center in the widthwise direction W of the absorbent body 6 (i.e., it is situated on the widthwise center axis CL that runs in the lengthwise direction L). Since the upper layer groove 61S is thus formed at a location corresponding to the location where excreted fluid such as urine discharged from the wearer is supplied, excreted fluid such as urine that has been discharged from the wearer can be rapidly taken up into the lower absorbing layer 62 through the upper layer groove 61S, before it diffuses on the top sheet 5 (i.e., essentially without soiling the skin-facing surface of the urine-absorbing pad 1).

[01311 For the fourth embodiment, the lower absorbing layer 62 has a lower layer groove 62S extending along the lengthwise direction L in the crotch region 3 and penetrating the lower absorbing layer 62 in the thickness direction T. As shown in Fig. 12, the lower layer groove 62S is situated in the crotch region 3 of the urine-absorbing pad 1, while extending in the lengthwise direction L through the center in the widthwise direction W of the absorbent body 6 (i.e., it is situated on the widthwise center axis CL that extends in the lengthwise direction L), being formed in a manner overlapping with the upper layer groove 61S in the thickness direction T (i.e., overlapping in the plan view). Therefore, excreted fluid such as urine that has been discharged can be rapidly taken up into the lower absorbing layer 62 through the upper layer groove 61S of the upper absorbing layer 61 and the lower layer groove 62S of the lower absorbing layer 62. Incidentally, it is not an essential constituent feature of the absorbent article of the invention for the lower absorbing layer to have a lower layer groove penetrating the lower absorbing layer in the thickness direction, and the lower absorbing layer may lack such a lower layer groove, or it may be formed as a recess that is depressed in the thickness direction from the skin-facing surface side toward the non-skin-facing surface side of the lower absorbing layer.

[0132] The upper layer groove 61S and lower layer groove 62S of the fourth embodiment may also be formed so that their respective locations match in the plan view (i.e., so that both grooves are communicating with each other in the thickness direction). Therefore, a groove 6S is formed in the absorbent body 6 with the upper layer groove 61S and lower layer groove 62S overlapping in the thickness direction T. This will allow the absorbent body 6 of the fourth embodiment to rapidly take up excreted fluid such as urine that has been discharged, into the lower absorbing layer 62 through the upper layer groove 61S of the upper absorbing layer 61 and the lower layer groove 62S of the lower absorbing layer 62, while also making it less likely that excreted fluid such as urine that has been absorbed into the lower absorbing layer 62 will rewet, due to the intervening upper absorbing layer 61.

[01331 The length in the lengthwise direction L and the length in the widthwise direction W of the upper layer groove 61S and lower layer groove 62S in the plan view (the "lengthwise length" of the grooves will hereunder be referred to as "length", and the widthwise length of the grooves will be referred to as the "width") may be of any desired sizes in consideration of the sizes of the upper absorbing layer 61 and the lower absorbing layer 62, from the viewpoint of the desired absorption performance and flexibility. For example, the width of the upper layer groove 61S may be in the range of usually 5.0 to 50 mm and is preferably in the range of 10 to 20 mm. Similarly, the width of the lower layer groove 62S is equal to or narrower than the width of the upper layer groove 61S, and is in the range ofusually 5.0 to 40 mm and preferably in the range of 10 to 15 mm. The length of the upper layer groove 61S is in the range of usually 50 to 300 mm, preferably in the range of 50 to 200 mm and even more preferably in the range of 50 to 150 mm. Similarly, the length of the lower layer groove 62S is equal to or narrower than the length of the upper layer groove 61S, and is in the range of usually 30 to 250 mm and preferably in the range of 30 to 150 mm. If the width and length of the upper layer groove 61S are equal to or greater than the width and length of the lower layer groove 62S, respectively, then the size of the groove 6S will be kept essentially constant in the plan view of the absorbent body 6, even with some shifting during the step of layering the upper absorbing layer 61 and the lower absorbing layer 62 or during movement when the article is worn. Furthermore, since a level difference is produced on the inner wall surface of the groove 6S and the surface area of the groove 6S is increased, it is possible to increase the absorption performance of the absorbent body 6 at the portion where the groove 6S has been formed.

[0134] The groove 6S of the absorbent body 6 for the fourth embodiment will now be described in further detail. As shown in Fig. 13 and Fig. 14, the upper layer groove 61S comprises a pair of wall faces running along the lengthwise direction L and situated facing each other in the widthwise direction W, i.e. a wall face SU1 of one side edge WU1 in the widthwise direction W and a wall face SU2 of the other side edge WU2 in the widthwise direction W, and a pair of wall faces running along the widthwise direction W and situated facing each other in the lengthwise direction L, i.e. a wall face FWU of the abdominal side edge LU1 in the lengthwise direction L and a wall face BWU of the dorsal side edge LU2 in the lengthwise direction L, while the lower layer groove 62S comprises a pair of wall faces running along the lengthwise direction L and situated facing each other in the widthwise direction W, i.e. a wall face SLI on one side edge WL1 in the widthwise direction W and a wall face SL2 on the other side edge WL2 in the widthwise direction W, and a pair of wall faces running along the widthwise direction W and situated facing each other in the lengthwise direction L, i.e. a wall face FWL on the abdominal side edge LL1 in the lengthwise direction L and a wall face BWL on the dorsal side edge LL2 in the lengthwise direction L. In Fig. 13, the left side in the lengthwise direction L is the front end (abdomen side), and the right side is the rear end in the lengthwise direction L (dorsal side). The virtual bottom side BU of the upper layer groove 61S is a plane imaginarily extending to the upper layer groove 61S, as a perforation through the non-skin-facing surface of the upper absorbing layer 61. Similarly, the virtual bottom side BL of the lower layer groove 62S is a plane imaginarily extending to the lower layer groove 62S, as a perforation through the non skin-facing surface of the lower absorbing layer. Therefore, the virtual bottom side BU of the upper layer groove 61S and the virtual bottom side BL of the lower layer groove 62S are in a mutually parallel relationship.

[01351 In the urine-absorbing pad 1 of the fourth embodiment, as shown in Fig. 12 and Fig. 13, the distance between the abdominal side edge LL1 in the lengthwise direction L of the lower layer groove 62S and the abdominal side edge 1A of the urine-absorbing pad 1 is shorter than the distance between the dorsal side edge LL2 in the lengthwise direction L of the lower layer groove 62S and the dorsal side edge 1B of the urine-absorbing pad 1. Also in the urine-absorbing pad 1 of the fourth embodiment, as shown in Fig. 13, the angle Pl formed between the wall face FWL of the abdominal side edge LL1 in the lengthwise direction L of the lower layer groove 62S and the virtual bottom side BL of the lower layer groove 62S is formed so as to be more nearly perpendicular and steeper with respect to the virtual bottom side BL than the angle P2 formed between the wall face BWL of the dorsal side edge LL2 in the lengthwise direction L of the lower layer groove 62S and the virtual bottom side BL of the lower layer groove 62S. For example, when the wearer is in an erect or a sitting posture, and excreted fluid such as urine that has been discharged from the wearer leaks out from the abdominal side edge LL1 in the lengthwise direction L of the lower layer groove 62S, the leaked excreted fluid tends to flow through the upper layer groove 61S toward the abdominal side edge 1A of the urine-absorbing pad 1; however, if the lower layer groove 62S is formed as described above, then excreted fluid such as urine that leaks out from the abdominal side edge LL1 in the lengthwise direction L of the lower layer groove 62S can be less likely to be directed toward the abdominal side edge 1A of the urine-absorbing pad 1.

[01361 In the urine-absorbing pad 1 of the fourth embodiment, as shown in Fig. 12 and Fig. 13, the distance between the abdominal side edge LU1 in the lengthwise direction L of the upper layer groove 61S and the abdominal side edge 1A of the urine-absorbing pad 1 is shorter than the distance between the dorsal side edge LU2 in the lengthwise direction L of the upper layer groove 61S and the dorsal side edge 1B of the urine-absorbing pad 1. Also in the urine-absorbing pad 1 of the fourth embodiment, as shown in Fig. 13, the angle al formed between the wall face FWU of the abdominal side edge LU1 in the lengthwise direction L of the upper layer groove 61S and the virtual bottom side BU of the upper layer groove 61S is formed so as to be more nearly perpendicular and steeper with respect to the virtual bottom side BU than the angle a2 formed between the wall face BWU of the dorsal side edge LU2 in the lengthwise direction L of the upper layer groove 61S and the virtual bottom side BU of the upper layer groove 61S. If the upper layer groove 61S is formed in this manner, than when the wearer is in an erect or a sitting posture, excreted fluid such as urine that leaks from the abdominal side edge LU1 in the lengthwise direction L of the upper layer groove 61S will be less likely to be directed toward the abdominal side edge 1A of the urine-absorbing pad 1, similar to the lower layer groove 62S.

[01371 In the urine-absorbing pad 1 of the fourth embodiment, as shown in Fig. 13 and Fig. 14, the angles P 1, P2, P3, P4 formed respectively between each of the wall faces FWL, BWL, SLI, SL2 of the lower layer groove 62S and the virtual bottom side BL of the lower layer groove 62S are formed more nearly perpendicular and steeper with respect to the virtual bottom sides BU, BL, than the angles al, u 2 , 03, a4 formed between each of the wall faces FWU, BWU, SUl, SU2 of the upper layer groove 61S and the virtual bottom side BU of the upper layer groove 61S. In other words, each of the wall faces FWU, BWU, SU1, SU2 of the upper layer groove 61S are formed more gently with respect to the virtual bottom sides BL, BU of the groove 6S, than each of the wall faces FWL, BWL, SLI, SL2 of the lower layer groove 62S. Therefore, since each of the wall faces FWU, BWU, SU1, SU2 of the upper layer groove 61S are more gently formed in the urine-absorbing pad 1 of the fourth embodiment, excreted fluid such as urine is more easily taken up into the lower layer groove 62S through the upper layer groove 61S, and since the wall faces FWL, BWL, SLI, SL2 of the lower layer groove 62S are more steeply formed, excreted fluid such as urine that has already been taken up into the lower absorbing layer 62 is less likely to rewet.

[01381 Furthermore, in the urine-absorbing pad 1 of the fourth embodiment, as shown in Fig. 12 to Fig. 14, the distance between one side edge WUIin the widthwise direction W of the upper layer groove 61S and one side edge in the widthwise direction W of the urine-absorbing pad 1, and the distance between the other side edge WU2 in the widthwise direction W of the upper layer groove 61S and the other side edge in the widthwise direction W of the urine-absorbing pad 1, are shorter than the distance between the abdominal side edge LU1 in the lengthwise direction L of the upper layer groove 61S and the abdominal side edge 1A in the lengthwise direction L of the urine-absorbing pad 1, and the distance between the dorsal side edge LU2 in the lengthwise direction L of the upper layer groove 61S and the dorsal side edge 1B in the lengthwise direction L of the urine-absorbing pad 1. Also in the urine-absorbing pad 1 of the fourth embodiment, as shown in Fig. 12 and Fig. 13, the angles 03, C4 formed between the respective wall faces SUl, SU2 of the one side edge WUl and the other side edge WU2 in the widthwise direction W of the upper layer groove 61S and the virtual bottom side BU of the upper layer groove 61S, are formed to be more nearly perpendicular and steeper with respect to the virtual bottom side BU than the angle a Iformed between the wall face FWU of the abdominal side edge LU1 in the lengthwise direction L of the upper layer groove 61S and the virtual bottom side BU of the upper layer groove 61S, and the angle a2 formed between the wall face BWU of the dorsal side edge LU2 in the lengthwise direction L of the upper layer groove 61S and the virtual bottom side BU of the upper layer groove 61S. Since the urine-absorbing pad 1 of the fourth embodiment comprises an upper layer groove 61S having the structure specified above, excreted fluid such as urine that has been discharged by the wearer easily reaches the lower absorbing layer 62 through the upper layer groove 61S, and even if the excreted fluid temporarily pools in the upper layer groove 61S, the excreted fluid can be preferentially diffused in the lengthwise direction L. Thus, the urine absorbing pad 1 of the fourth embodiment can efficiently absorb excreted fluid such as urine over a wide area in the lengthwise direction L of the absorbent body 6 while minimizing rewetting by excreted fluid that has been absorbed into the lower absorbing layer 62, by the presence of the upper absorbing layer 61, and therefore excreted fluid such as urine and its humidity are less likely to contact the skin of the wearer, and it is possible to further prevent the wearer from sensing a state of wetness or mustiness and prevent the skin of the wearer from being in a wet state.

[01391 Measurement of the angles l1-a4 and P 1-p4 formed between each of the wall faces of the grooves and each of the virtual bottom sides may be carried out by the following measuring method. First, a 20 x 40 mm measuring sample is cut out from the absorbent article to be measured, with the groove at the center. Next, an FLEX-M863 X-ray fluoroscope by Beamsense Co. is used for a 360-degree scan while rotating the measuring sample 0.2 degrees at a time, with an image being taken at each angle. Next, the 1800 photographed images are combined to form a 3D image. A cross-sectional view in the lengthwise direction L and a cross-sectional view in the widthwise direction W are extracted from the formed 3D image, and the angles l1-a4 and P1-p4 are measured from the respective views.

[0140]

The present invention can be applied to a variety of absorbent articles other than a urine absorbing pad as in the embodiments described above, such as a (light) incontinence pad or disposable diaper. Moreover, the absorbent article of the invention is not limited to each of the embodiments and modified examples described above, and it may incorporate appropriate combinations, substitutes and modifications within a range that is still within the object and gist of the invention. Incidentally, the ordinal terms "first" and "second" as used throughout the present description serve merely to distinguish between the numbered embodiments and are not used to mean any relative ordering, precedence or importance.

EXAMPLES

[0141] The invention will now be explained in greater detail using examples and comparative examples, with the understanding that the invention is not limited only to these examples.

[0142] Example 1 (1) Production of low friction member A master batch comprising 50 mass% high-density polyethylene (HDPE) and 50 mass% low-density polyethylene, an antioxidant and a slip agent were loaded into an extruder, and after melt kneading in the extruder, the melt kneaded mixture in the extruder was extruded through a T-die into the form of a sheet to obtain a molded sheet. Immediately after extrusion, the molded sheet was supplied along the surface of a suction drum covered with a mesh, and a plurality of openings were formed in the semi-molten molded sheet along the opening pattern of the mesh, by the suction force of a suction drum that performed suction while rotating, while also forming rib sections that protruded from the opening perimeter edges of the openings. The semi-molten molded sheet was then cooled to solidification by suction by the suction drum and by a chilling roll in the subsequent step, to obtain a polyethylene sheet (low friction member) comprising a plurality of openings with the specific rib sections shown in Table 1. (2) Production of absorbent article Of the two surfaces of the obtained polyethylene sheet (low friction member), the surface on the side where the rib sections were protruding (i.e., the surface that was to be the non-skin facing surface side when disposed in the absorbent article) was coated with a hot-melt adhesive, and the low friction member was joined to the surface of an absorbent article precursor comprising a top sheet (a hydrophilic air-through nonwoven fabric with a basis weight of 25

g/m2), an interlayer sheet (a tissue with a basis weight of 15 g/m2), an absorbent body (a laminated absorbent body constructed of an upper absorbing layer having pulp with a basis weight of 300 g/m2 and a superabsorbent polymer with a basis weight of 110 g/m 2 , and a lower absorbing layer having pulp with a basis weight of 215 g/m2 and a superabsorbent polymer with a basis weight of 80 g/m2), and a back sheet (a liquid-impermeable film with a basis weight of

22 g/m2), in that order, on the skin-facing surface side of the top sheet, to obtain an absorbent article for Example 1. For this Example, the absorbent article was not provided with a cover sheet, in order to evaluate the rewet property at the portion where the low friction member was disposed, as explained below.

[0143] Examples 2 and 3 Absorbent articles were obtained for Examples 2 and 3 in the same manner as Example 1, except that the respective low friction members were changed to have the structure shown in Table 1.

[0144] Comparative Example 1 An absorbent article was obtained for Comparative Example 1 in the same manner as Example 1, except that the low friction member used was a nylon sheet without rib sections in the openings.

[0145] Comparative Example 2 An absorbent article was obtained for Comparative Example 2 in the same manner as Example 1, except that the low friction member was disposed so that the rib sections protruded to the skin-facing surface side.

[0146] The absorbent articles of Examples 1 to 3 and Comparative Examples 1 to 2 were measured for frictional coefficient on the surfaces of the skin-facing surface sides of the low friction members, by the following <Method of measuring static friction coefficient and dynamic friction coefficient>, and were also measured for rewetting amounts on the portions where the low friction members were disposed, by the following <Method of measuring rewetting amount>, in order to evaluate the frictional properties and rewet properties of the portions where the low friction members were disposed. The compositions of the low friction members, and the measurement results for the frictional coefficients and rewetting amounts, are shown in Table 1 below.

[01471 <Method of measuring static friction coefficient and dynamic friction coefficient> (1) The cover sheet to be used in the absorbent article is prepared separately, and a 1 kg weight with a bottom side size of 50 mm x 50 mm and having a pressure-sensitive adhesive on the bottom side is placed on the cover sheet to bond the weight to the cover sheet. (2) The low friction member used for production of the absorbent article to be measured is set on a horizontal plane with the surface on the skin-facing surface side as the top side. (3) The cover sheet with the 1 kg weight bonded is placed on the top side of the low friction member set on the horizontal plane, with the weight situated above. (4) An arbitrary friction tester is used to pull the weight at a speed of 100 mm/min in the direction parallel to the horizontal plane and corresponding to the lengthwise direction of the absorbent article, and the frictional coefficient during and after movement of the weight is measured, the measured frictional coefficients being recorded as the static friction coefficient and dynamic friction coefficient, respectively.

[01481 <Method of measuring rewetting amount> (1) A cylinder (inner diameter: 60 mm, weight: 550 g) is placed at an artificial urine dropping location of the absorbent article to be measured (hereunder referred to as "measuring sample") (specifically, the center section of the low friction member in the plan view), and 150 ml of artificial urine is dropped, using a burette, from a position 10 mm above the measuring sample at approximately the center section of the cylinder, at a speed of 150 ml/15 sec. Dropping of 150 ml of artificial urine is conducted twice with an interval of 5 minutes, thus dropping a total of 300 ml of artificial urine onto the measuring sample. The artificial urine used for the measurement is prepared by dissolving 200 g ofurea, 80 g of sodium chloride, 8 g of magnesium sulfate, 3 g of calcium chloride and approximately 1 g of dye (Blue #1) in 10 L of ion-exchanged water. (2) After 5 minutes elapses from dropping the total of 300 ml of artificial urine, 70 g of filter paper (100 mm x 100 mm) is placed on the artificial urine dropping location and a 3.5 kg weight with a bottom side size of 100 mm x 100 mm is placed over it, allowing the filter paper to absorb the artificial urine seeping from the measuring sample. (3) After standing for 3 minutes, the weight of the artificial urine-absorbed filter paper is measured. The weight of the filter paper before absorption of the artificial urine is subtracted from the weight of the filter paper after absorption of the artificial urine, calculating the weight (g) of the artificial urine absorbed by the filter paper and recording it as the rewetting amount (g).

[0149]

[Table 1]

~-cn

bb CC )

o tb

.- ~~b

CI

Coo

~-x

o b4

CD C

[0150] As shown in Table 1, the absorbent articles of Examples 1 to 3 which comprised low friction members having rib sections protruding to the non-skin-facing surface side had low frictional coefficients on the skin-facing surfaces of the low friction members, and maintained the low-friction property of the low friction members (i.e., low friction resistance between the cover sheets and low friction members) while having reduced rewetting amounts. However, the absorbent article of Comparative Example 1 which comprised a low friction member without rib sections had a low frictional coefficient on the skin-facing surface of the low friction member, and a large rewetting amount. The absorbent article of Comparative Example 2 which comprised a low friction member having rib sections protruding to the skin-facing surface side had a considerably high frictional coefficient on the skin-facing surface of the low friction member, and the rewetting amount was also large.

[0150A] Any reference to or discussion of any document, act or item ofknowledge in this specification is included solely for the purpose of providing a context for the present invention. It is not suggested or represented that any of these matters or any combination thereof formed at the priority date part of the common general knowledge, or was known to be relevant to an attempt to solve any problem with which this specification is concerned.

[0150B] In this specification, the terms 'comprises', 'comprising', 'includes', 'including', or similar terms are intended to mean a non-exclusive inclusion, such that a method, system or apparatus that comprises a list of elements does not include those elements solely, but may well include other elements not listed.

REFERENCE SIGNS LIST

[0151] 1 Urine-absorbing pad (absorbent article) 2 Abdominal region 3 Crotch region 4 Dorsal region 5 Top sheet 6 Absorbent body 7 Back sheet 8 One side sheet 9 Other side sheet

10 Anti-leakage sheet 11 Elastic member 12 Anti-leakage wall section 13 Cover sheet 14 Low friction member 15 Joining section 16 Opening 17 Opening perimeter edge 18 Rib section 19 Protrusion-recess structure 20 Absorbent sheet

Claims

[Claim 1] An absorbent article comprising a top sheet and an absorbent body situated on a non skin-facing surface side of the top sheet, and having a lengthwise direction, a widthwise direction and a thickness direction, wherein: the absorbent article has, in a plan view, an abdominal region, a dorsal region, and a crotch region located between these two regions, in the lengthwise direction, the absorbent article further comprises, in at least the dorsal region, a low friction member situated on a skin-facing surface side of the top sheet and having a plurality of openings penetrating the thickness direction, and a cover sheet situated on the skin-facing surface side of the low friction member, and each of the plurality of openings has an opening perimeter edge located on the skin-facing surface side and a rib section protruding from the opening perimeter edge toward a non-skin-facing surface side.
[Claim 2] The absorbent article according to claim 1, wherein a product of a height (hr) and thickness (tr) of the rib section is in a range of 2.0 x 10-3 mm to 5.0 x 10- mm
[Claim 3] The absorbent article according to claim 1 or 2, wherein the opening perimeter edge has a skin-facing surface thereof curved toward the non-skin-facing surface side.
[Claim 4] The absorbent article according to any one of claims 1 to 3, wherein at the rib section, a rigidity of a tip section located on the non-skin-facing surface side is higher than a rigidity of the opening perimeter edge.
[Claim 5] The absorbent article according to any one of claims 1 to 4, wherein at the rib section, a tip section located on the non-skin-facing surface side is situated in an interior of the top sheet.
[Claim 6] The absorbent article according to any one of claims 1 to 5, wherein the top sheet has a protrusion-recess structure in which an elevated section protruding toward the skin-facing surface side in the thickness direction of the absorbent article and running continuously in a prescribed first direction, and a groove section depressed toward the non-skin-facing surface side in the thickness direction and running continuously in the first direction, are arranged alternately along a second direction that is perpendicular to the first direction.
[Claim 7] The absorbent article according to claim 6, wherein the rib section has a tip section thereof located on the non-skin-facing surface side overlapping with the elevated section in the thickness direction.
[Claim 8] The absorbent article according to claim 6, wherein the rib section has a tip section thereof located on the non-skin-facing surface side overlapping with the groove section in the thickness direction.
[Claim 9] The absorbent article according to any one of claims 1 to 8, wherein the absorbent article further comprises an absorbent sheet that includes a superabsorbent polymer, between the top sheet and the absorbent body, the absorbent sheet overlapping with the low friction member in the thickness direction.
[Claim 10] The absorbent article according to any one of claims 1 to 9, wherein: the absorbent body comprises an upper absorbing layer situated on the skin-facing surface side and a lower absorbing layer situated on the non-skin-facing surface side, the upper absorbing layer has, in the crotch region, an upper layer groove extending in the lengthwise direction and penetrating the upper absorbing layer in the thickness direction, and in the upper layer groove, an angle formed between wall faces on one side edge and the other side edge in the widthwise direction and a virtual bottom side of the upper layer groove is more nearly perpendicular than an angle formed between wall faces of an abdominal side edge and a dorsal side edge in the lengthwise direction and the virtual bottom side of the upper layer groove.
[Claim 11] The absorbent article according to any one of claims 1 to 10, wherein the low friction member is formed of a resin sheet-like member including high-density polyethylene at 50 mass% or greater.
[Claim 12] The absorbent article according to claim 11, wherein the resin sheet-like member includes the high-density polyethylene and low-density polyethylene in a mass ratio in a range of 50/50 to 75/25.
[Claim 13] The absorbent article according to any one of claims 1 to 12, wherein the top sheet and low friction member are joined at least partially via a low-tack adhesive having a measured value of 0.78 N in a probe tack test.
[Claim 14] The absorbent article according to any one of claims 1 to 13, wherein the low friction member is formed by a sheet-like member in which both ends in the widthwise direction are displaced toward the skin-facing surface side.
[Claim 15] The absorbent article according to any one of claims 1 to 14, wherein the absorbent article has at least one folding line running in the widthwise direction, for folding of an expanded absorbent article in the lengthwise direction, and the low friction member is disposed at a location that does not overlap with the folding line, in the plan view.