JP7569671B2 - Disposable diapers - Google Patents

Description

The present invention relates to a disposable diaper.

In general, pants-type disposable diapers have leak-proof cuffs on both sides along the longitudinal direction of the absorbent body to prevent leakage of excrement. For example, Patent Document 1 describes an absorbent article in which the leak-proof cuffs are made to stand up by contracting an elastic member arranged near the free end, and also discloses that a softening embossing process is applied to the free end side of the leak-proof cuffs.

The applicant has also disclosed an absorbent article having a leak-proof wall that is hollow inside (Patent Document 2). The absorbent article described in Patent Document 2 has a leak-proof wall that is highly stable in standing, and can achieve high leakage prevention.

JP 2017-023782 A JP 2009-207599 A

When the wearer moves while wearing the product, the skin rubs against the leak-preventing cuffs, which may result in skin troubles such as redness. Although the leak-preventing cuffs described in Patent Document 1 have softening embossing on the tip side, they cannot prevent the leak-preventing cuffs from rubbing against the wearer's skin, which may cause skin troubles. The leak-preventing wall described in Patent Document 2 has a complex structure because it is hollow inside. Furthermore, the absorbent article described in Patent Document 2 did not give any particular consideration to preventing rubbing between the skin and the leak-preventing cuffs, which have elastic members at their free ends.

Therefore, the objective of the present invention is to provide a disposable diaper that prevents the leak-proof cuffs from rubbing against the wearer's skin, thereby suppressing the occurrence of skin problems.

The present invention relates to a disposable diaper having a longitudinal direction corresponding to the front-to-rear direction of a wearer and a width direction perpendicular to the longitudinal direction, and having a ventral side portion arranged on the ventral side of the wearer when worn, a dorsal side portion arranged on the dorsal side, and a crotch portion located between the ventral side portion and the dorsal side portion, and having a longitudinally elongated absorbent main body including a liquid-permeable top sheet and an absorbent body, and a pair of leakproof cuffs arranged on both sides of the longitudinal direction of the absorbent main body along the longitudinal direction.
It is preferable that the leakproof cuff is composed of two opposing sheets of nonwoven fabric, has a free end at one end and a fixed end at the other end of the width direction, has end fixing portions fixed to the absorbent body near both ends in the longitudinal direction, and has a free end stretch portion near the free ends in which an elastic member is fixed between the two sheets of nonwoven fabric via an adhesive.
It is preferable that there is a slippage region between the free end stretchable portion and the fixed end where the two nonwoven fabrics are not joined, and that in the slippage region, the friction coefficient between the opposing surfaces of the two nonwoven fabrics is 0.275 or less, the length along the longitudinal direction is longer than the length along the width direction, and the length along the width direction is three or more times the length along the width direction of the free end stretchable portion.

The disposable diaper of the present invention prevents the leak-proof cuffs from rubbing against the wearer's skin, thereby reducing the occurrence of skin problems.

FIG. 1 is a perspective view illustrating a disposable diaper according to one embodiment of the present invention. FIG. 2 is a developed plan view showing a schematic view of the skin-facing side (inner surface side) of the diaper shown in FIG. 1 in a fully extended state. FIG. 3 is a schematic cross-sectional view taken along line III-III of FIG. FIG. 4 is an enlarged cross-sectional view showing a schematic cross section of the leak-proof cuff shown in FIG.

The present invention will be described below based on preferred embodiments with reference to the drawings. Figs. 1 and 2 show a pants-type disposable diaper 1 according to one embodiment of the present invention. As shown in Figs. 1 and 2, the diaper 1 has a ventral portion F that is disposed on the ventral side of the wearer when the diaper 1 is worn, a dorsal portion R that is disposed on the dorsal side of the wearer, and a crotch portion M located therebetween. The ventral portion F and the dorsal portion R are connected in a ring shape to form a waist portion that is disposed around the wearer's waist when the diaper 1 is worn. The diaper 1 has a longitudinal direction X that corresponds to the front-rear direction of the wearer, i.e., the direction extending from the ventral portion F through the crotch portion M to the dorsal portion R, and a width direction Y that is perpendicular thereto. The diaper 1 includes an absorbent body 2 and an exterior body 3 that is disposed on the non-skin-facing side of the absorbent body 2.

In this specification, the "skin-facing side" refers to the side of a disposable diaper or its constituent members (e.g., absorbent body) that faces the wearer's skin when the diaper is worn, i.e., the side that is relatively closer to the wearer's skin, and the "non-skin-facing side" refers to the side of a disposable diaper or its constituent members that faces away from the skin when the disposable diaper is worn, i.e., the side that is relatively farther from the wearer's skin. Note that "when worn" here refers to the normal, proper wearing state, i.e., the state in which the disposable diaper is being worn correctly.

In the diaper 1, both sides of the abdominal portion F and both sides of the dorsal portion R of the outer cover 3 are joined together by a joining means such as adhesive, heat sealing, ultrasonic sealing, etc. As shown in FIG. 1, the diaper 1 is a pants-type disposable diaper. The diaper 1 is formed with a pair of side seal portions S, S, a waist opening WH through which the wearer's torso passes, and a pair of leg openings LH, LH through which the wearer's lower legs pass.

As shown in FIG. 2, the abdominal portion F, the back portion R, and the crotch portion M are the three regions of the diaper 1 when the diaper 1 is in an unfolded and stretched state, by dividing the entire length of the diaper 1 in the longitudinal direction X into three equal parts. In the diaper 1 in the state shown in FIG. 2, the absorbent body 2 is a substantially rectangular shape that is long in the longitudinal direction X. The absorbent body 2 is disposed in the region from the abdominal portion F to the back portion R in the outer body 3. In a pants-type disposable diaper such as the diaper 1, the "unfolded and stretched state" refers to a state in which the diaper 1 is separated at the side seal portion S to be in an unfolded state, and the elastic members of each portion of the diaper 1 in the unfolded state are stretched to the designed dimensions (the same dimensions as when the diaper 1 is unfolded flat in a state in which the influence of the elastic members is completely eliminated). In the case of an unfolded disposable diaper, the "unfolded and stretched state" refers to a state in which the diaper 1 is unfolded to the designed dimensions by stretching the elastic members of each portion. The absorbent body 2 is disposed in the center of the outer body 3 in the width direction Y. The absorbent body 2 is joined to the exterior body 3 by a joining means such as an adhesive.

As shown in FIG. 2, the absorbent body 2 comprises a liquid-retentive absorbent 4 and a liquid-permeable top sheet 5 that forms the skin-facing surface of the diaper 1. As shown in FIG. 3, the top sheet 5 covers the entire absorbent 4 and extends outward from the side edges of the absorbent 4 in the longitudinal direction X. The absorbent 4 and the top sheet 5 are joined by a known joining means such as an adhesive. The absorbent 4, like the absorbent body 2, has an elongated shape in the longitudinal direction X of the diaper 1.

As shown in Figs. 2 and 3, the absorbent body 4 comprises an absorbent core 40 and a core wrap sheet 41 that covers the absorbent core 40. The absorbent core 40 is made of a fiber aggregate or a fiber aggregate that holds a water-absorbent polymer. The core wrap sheet 41 is made of tissue paper or a water-permeable nonwoven fabric. The core wrap sheet 41 preferably covers the entire skin-facing side and non-skin-facing side of the absorbent core 40.

The absorbent core 40 is a single layer as shown in FIG. 3. The absorbent core 40 may or may not have a flexible portion on the inside in the width direction Y. Examples of the flexible portion include a slit penetrating the absorbent core 40 or a low basis weight portion having a low basis weight. When the absorbent core 40 has a flexible portion, the side region 43 along the longitudinal direction X of the absorbent main body 2 is easily raised around the flexible portion when worn, and excrement such as urine can be prevented from flowing outward in the width direction Y. In the embodiment shown in FIG. 3, the flexible portion includes a pair of slits 44, 44 extending in the longitudinal direction X. The slits 44 are disposed at least inwardly away from both side edges of the absorbent core 40 along the longitudinal direction X in the crotch portion M. The side regions 43 of the absorbent main body 2 are portions located outward in the width direction Y from the positions corresponding to the slits 44 in the absorbent main body 2. From the viewpoint of facilitating the standing of the side regions 43, it is preferable that the basis weight of the side regions 43 is smaller than the basis weight of the central region 42 sandwiched between the pair of slits 44, 44. When a low basis weight portion is provided instead of the slits 44, the basis weight of the low basis weight portion is preferably 0 g/ ^m2 or more and 300 g/m2 ^or less, more preferably more than 0 g/ ^m2 and 300 g/m2 ^{or less} , and even more preferably 80 g/m2 or ^more and 120 g/m2 ^or less. The absorbent core 40 may be multi-layered.

As shown in FIG. 3, the non-skin facing side of the absorbent body 2 is covered with a liquid-impermeable leak-proof sheet 7 made of a resin film. The concept of liquid impermeability in relation to the leak-proof sheet 7 includes poor liquid permeability. The leak-proof sheet 7 is arranged so as to cover the entire non-skin facing side of the absorbent body 4. The leak-proof sheet 7, the nonwoven fabric 60 constituting the leak-proof cuff 6, and the absorbent body 2 are joined in sequence to the skin facing side of the exterior body 3 with an adhesive such as a hot melt adhesive.

As shown in FIG. 3, the outer body 3 of the diaper 1 is composed of two sheets 31 and 32 for forming the outer body and elastic members of each part fixed between these two sheets in a stretched state. Between the two sheets 31 and 32 for forming the outer body, as shown in FIG. 2, there are arranged a waist elastic member 33 for forming waist gathers at the periphery of the waist opening WH, a leg elastic member 34 for forming leg gathers at the periphery of the leg opening LH, and a waist elastic member 35 for forming waist gathers at the waist part. The waist part refers to the area from a position 20 mm below the periphery of the waist opening WH to the upper end of the leg opening LH. The elastic members 33, 34, and 35 are fixed between the sheets 31 and 32 in a stretched state by any joining means such as a hot melt adhesive.

As shown in FIG. 2, the absorbent body 2 is provided with a pair of leak-proof cuffs 6, 6 on both sides along the longitudinal direction X of the skin-facing surface. The leak-proof cuffs 6 are composed of two opposing nonwoven fabrics 60, 60. The two nonwoven fabrics may be separate nonwoven fabrics or a single nonwoven fabric folded over. In the embodiment shown in FIG. 3, the leak-proof cuffs 6 are composed of a single nonwoven fabric 60 folded over in the width direction Y and two nonwoven fabrics 60, 60 arranged to face each other.

The leak-proof cuffs 6 shown in FIG. 3 will be described. The diaper 1 of this embodiment has, as the leak-proof cuffs 6, a pair of first leak-proof cuffs 6A, 6A and a pair of second leak-proof cuffs 6B, 6B located outward in the width direction Y from the pair of first leak-proof cuffs 6A, 6A. The nonwoven fabric 60 is folded back in the width direction Y above the absorbent body 4, and is folded back in the width direction Y at a portion located outward from the side edge along the longitudinal direction X of the absorbent body 4. The nonwoven fabric 60 folded in this manner is joined to the top sheet 5 or the leak-proof sheet 7. The joint 68 formed by this joining extends along the longitudinal direction X. The joint 68 is arranged along the side edge along the longitudinal direction X of the absorbent body 4 and is arranged outward from the side edge. The first leak-proof cuff 6A is formed at the portion of the nonwoven fabric 60 folded back above the absorbent body 4, and is formed on the inner side in the width direction Y from the joint 68. On the other hand, the second leakage prevention cuff 6B is formed by folding back the nonwoven fabric 60 from the side edge of the absorbent body 4 outward, and is formed on the outer side in the width direction Y of the joint 68. The joint 68 can be formed using a known joining method such as heat sealing, ultrasonic sealing, or hot melt adhesive.

The first leak-proof cuff 6A and the second leak-proof cuff 6B each have a free end 61 and a fixed end 62 at both ends in the width direction Y. Near the free end 61, one or more elastic members 63 are fixed between the two nonwoven fabrics 60, 60 with adhesive. Because the elastic members 63 are fixed in a stretched state in the longitudinal direction X, both leak-proof cuffs 6A and 6B have a free end stretchable portion 64 near the free end 61, that is, in the area from the free end 61 to the area where the elastic members 63 are fixed with adhesive. As shown in FIG. 3, the position of the joint 68 closest to the free end 61 is the fixed end 62. The fixed ends 62 of the first leak-proof cuff 6A and the second leak-proof cuff 6B are both formed outward from the side edge of the absorbent body 4 in the width direction Y and extend along the side edge 2s of the absorbent body 2.

From the viewpoint of the stretchability of the free end stretchable portion 64 in the longitudinal direction X, it is preferable that the number of elastic members 63 arranged in the free end stretchable portion 64 is two or more. From the same viewpoint, the thickness of the elastic members 63 is preferably 300 dtex or more, more preferably 700 dtex or more, and preferably 900 dtex or less, and more preferably 800 dtex or less.

As shown in FIG. 2, the first leak-preventing cuff 6A and the second leak-preventing cuff 6B each have end fixing parts 65, 65 fixed to the absorbent body 2 near both ends in the longitudinal direction X, i.e., in the ventral part F or the dorsal part R. At the end of the ventral part F and the end of the dorsal part R, the end fixing parts 65 of the first leak-preventing cuff 6A are formed in the part of the top sheet 5 that overlaps with the absorbent body 4. The end fixing parts 65 of the second leak-preventing cuff 6B are formed in the part of the leak-preventing sheet 7 that is located outward from the side edge of the absorbent body 4. The leak-preventing cuffs 6A, 6B are made to stand at least in the crotch part M by the elastic members 63 arranged in a stretched state contracting when the diaper 1 is worn. If the leak-preventing cuffs 6A, 6B stand up, urine and other excrement can be prevented from flowing outward in the width direction Y.

As shown in FIG. 3, the first leak-proof cuff 6A and the second leak-proof cuff 6B each have a slippage area 66 between the free end stretchable portion 64 and the fixed end 62, where the two nonwoven fabrics 60, 60 are not joined. The slippage area 66 is an area sandwiched between the inner end of the free end stretchable portion 64 in the width direction Y and the fixed end 62. The inner end is the position of the adhesive that fixes the elastic member 63 that constitutes the free end stretchable portion 64, and is the position closest to the fixed end 62 among the adhesive coating portions that extend from the free end 61 toward the fixed end 62 and fix the elastic member 63. When the inner end cannot be determined, it is an area sandwiched between the elastic member 63 that constitutes the free end stretchable portion 64 and the fixed end 62. The slippage area 66 is formed so that the length along the longitudinal direction X is longer than the length along the width direction Y. The shiftable area 66 extends between the ventral portion F and the dorsal portion R.

The two nonwoven fabrics 60, 60 that make up the slippage area 66 have a friction coefficient of 0.275 or less when the inner surfaces that are the opposing surfaces are brought into contact and a shear force is applied. The friction coefficient between the opposing surfaces of the two nonwoven fabrics 60, 60 in the slippage area 66 is measured by the following method.

[Method for measuring the coefficient of friction between opposing surfaces of two nonwoven fabrics in the slippage area]
First, the nonwoven fabric of the corresponding part is cut out from the product. Specifically, two sheets of nonwoven fabric 60, 60 constituting the part corresponding to the displaceable region 66 are cut out from the leakage preventing cuff 6. At this time, it is confirmed that there is no hot melt or the like attached to the displaceable region. Next, one of the two cut out sheets of nonwoven fabric is stretched so as not to have any wrinkles and attached to a flat horizontal plate with no unevenness. Then, the other nonwoven fabric is attached to the contact surface of the jig for friction measurement. The contact surface is set to a size of 10 mm in the width direction Y of the leakage preventing cuff 6 × 20 mm in the longitudinal direction X of the leakage preventing cuff 6. The other nonwoven fabric attached to the jig is placed on top of one of the nonwoven fabrics attached to the horizontal plate so that the opposing surfaces of the two sheets of nonwoven fabric 60, 60 constituting the displaceable region 66 face each other. If it is difficult to cut out the above dimensions of 10 mm in the width direction Y × 20 mm in the longitudinal direction X, it may be cut out to a specified size. Next, with a normal force (N) of 1.96 N applied to the jig to which the other nonwoven fabric is attached, the jig is moved 20 mm along the longitudinal direction X of the leak-proof cuff at a speed of 300-400 mm/min, and the maximum load at this time is determined as the frictional force (F). The frictional coefficient between the nonwoven fabrics is then calculated as follows: frictional force (F)/normal force (N). A force gauge such as the RZ-1 series manufactured by Aiko Engineering Co., Ltd. is used to measure the frictional force (F). 15 measurements are taken at different locations, N=15, and the average value is taken as the frictional coefficient between the nonwoven fabrics.

In the unfolded and stretched state, as shown in FIG. 3, the length L1 of the displaceable region 66 of each of the pair of first leak-preventing cuffs 6A, 6A along the width direction Y is three times or more than the length L2 of the free end stretchable portion 64 along the width direction Y. Similarly, the length L1 of the displaceable region 66 of each of the pair of second leak-preventing cuffs 6B, 6B is three times or more than the length L2 of the free end stretchable portion 64. When the diaper 1 includes the first leak-preventing cuffs 6A and the second leak-preventing cuffs 6B, it is preferable that the length L1 of either the first leak-preventing cuff 6A or the second leak-preventing cuff 6B is three times or more than the length L2, and it is even more preferable that the length L1 of the average value of the first leak-preventing cuffs 6A and the second leak-preventing cuffs 6B is three times or more than the length L2.

According to the diaper 1 of this embodiment, the leak-preventing cuff 6 has a slippage area 66 in which the friction coefficient between the opposing surfaces of the two nonwoven fabrics 60, 60 is 0.275 or less. Therefore, when the wearer moves his/her body while wearing the diaper 1 and the relative position between the skin and the leak-preventing cuff 6 shifts while in contact with the leak-preventing cuff 6, the opposing nonwoven fabrics 60, 60 can easily slip between each other in the slippage area 66 while maintaining contact between the skin and the leak-preventing cuff 6. Moreover, since the length L1 of the slippage area 66 in the width direction Y is three or more times the length L2 of the free end stretchable portion 64, the leak-preventing cuff 6 can easily slip between the opposing nonwoven fabrics 60, 60 over a wide range in the width direction Y, following the skin, and the surface of the slippage area 66 that abuts against the skin can easily move in the width direction Y. Furthermore, because the length of the shiftable area 66 in the longitudinal direction X is longer than the length L1 in the width direction Y, the shiftable area 66 can move easily in the width direction Y over a wide range in the longitudinal direction X, following the skin. As a result, the leakproof cuff 6 prevents the wearer's skin from rubbing against it, and the occurrence of skin problems such as redness can be suppressed.

In the diaper 1 of this embodiment, as shown in FIG. 3, the absorbent core 40 has a pair of slits 44, 44 that serve as flexible portions, so that when worn, the side regions 43 of the absorbent body 2 are prone to deformation starting from the slits 44. When worn, the nonwoven fabrics 60, 60 are prone to shifting in the shiftable regions 66 of the leak-proof cuffs 6, and in addition, the side regions 43 are prone to shifting and deforming starting from the slits 44, so that chafing of the skin by the leak-proof cuffs 6 can be further prevented.

To prevent the leak-proof cuff 6 from rubbing against the wearer's skin, it is preferable that the shiftable region 66 is present at least in the crotch region M, more preferably from the crotch region M to the dorsal region R, and even more preferably from the abdominal region F to the dorsal region R.

From the viewpoint of ensuring that the displaceable region 66 conforms well to the skin when worn and preventing the leak-proof cuff 6 from rubbing against the skin, the coefficient of friction between the opposing surfaces of the two nonwoven fabrics 60, 60 in the displaceable region 66 is preferably 0.275 or less, and more preferably 0.260 or less. The lower limit of the friction coefficient is preferably as close to 0 as possible, but if it is 0.220 or more, the displaceable region 66 can be given sufficient skin conformability.

From the viewpoint of making the slippage region 66 conform well to the skin when worn and preventing the skin from being rubbed by the leak-proof cuffs 6, the length L1 of the slippage region 66 is preferably 3 times or more, more preferably 5 times or more, and more preferably 10 times or less, more preferably 8 times or less, and more preferably 3 times or more and 10 times or less, and more preferably 5 times or more and 8 times or less. When the diaper 1 has the first leak-proof cuffs 6A and the second leak-proof cuffs 6B, it is preferable that either the first leak-proof cuffs 6A or the second leak-proof cuffs 6B satisfy the above-mentioned conditions for the length L1 and the length L2, and it is more preferable that the average value of the first leak-proof cuffs 6A and the second leak-proof cuffs 6B satisfy the above-mentioned conditions for the length L1 and the length L2. Regarding the first leak-preventing cuff 6A and the second leak-preventing cuff 6B, the length of the displaceable region 66 in the first leak-preventing cuff 6A in the width direction Y is preferably 3 times or more, more preferably 5 times or more, and preferably 10 times or less, more preferably 8 times or less, and preferably 3 times or more and 10 times or less, and more preferably 5 times or more and 8 times or less, compared to the length of the free end stretchable portion 64 in the first leak-preventing cuff 6A in the width direction Y. The length of the displaceable region 66 in the second leak-preventing cuff 6B in the width direction Y is preferably 2 times or more, more preferably 3 times or more, and more preferably 12 times or less, more preferably 10 times or less, and preferably 2 times or more and 12 times or less, and more preferably 3 times or more and 10 times or less, compared to the length of the free end stretchable portion 64 in the second leak-preventing cuff 6B in the width direction Y.

The length of the displaceable region 66 of the first leakproof cuff 6A along the width direction Y is preferably 10 mm or more, more preferably 15 mm or more, and preferably 35 mm or less, and more preferably 30 mm or less. The length of the displaceable region 66 of the second leakproof cuff 6B along the width direction Y is preferably 20 mm or more, more preferably 30 mm or more, and preferably 50 mm or less, and more preferably 40 mm or less.
The length of the stretchable free end 64 in the width direction Y of the first leakage preventing cuff 6A is preferably 2 mm or more, more preferably 3 mm or more, and preferably 15 mm or less, and more preferably 10 mm or less. The length of the stretchable free end 64 in the width direction Y of the second leakage preventing cuff 6B is preferably 3 mm or more, more preferably 5 mm or more, and preferably 20 mm or less, and more preferably 15 mm or less.

In the embodiment shown in FIG. 3, the leak-proof cuffs 6 having the shiftable region 66 are provided with two cuffs, a first leak-proof cuff 6A and a second leak-proof cuff 6B, so that the shiftable region 66 can move more easily in the width direction Y by conforming to the skin. As a result, the leak-proof cuffs 6 are further prevented from rubbing against the wearer's skin, and the occurrence of skin troubles such as redness can be further suppressed.

From the viewpoint of further improving the ease of slippage between the first leak-preventing cuff 6A and the second leak-preventing cuff 6B, it is preferable that the friction coefficient between the mutually adjacent surfaces of the first leak-preventing cuff 6A and the second leak-preventing cuff 6B is 0.275 or less, and more preferably 0.260 or less. The lower limit of the friction coefficient is preferably as close to 0 as possible, but if it is 0.220 or more, it is possible to sufficiently cause slippage between the first leak-preventing cuff 6A and the second leak-preventing cuff 6B. The mutually adjacent surfaces are the skin-facing surfaces of the nonwoven fabrics 60, 60 that are located on the skin-facing side of the two nonwoven fabrics 60, 60 that constitute the first leak-preventing cuff 6A and the second leak-preventing cuff 6B in the deployed and extended state shown in FIG. 3. The friction coefficient between the first leak-preventing cuff 6A and the second leak-preventing cuff 6B is measured by the same method as the method for measuring the friction coefficient between the opposing surfaces of the two nonwoven fabrics 60, 60 in the slippage-possible region 66 described above.

From the viewpoint of allowing the shiftable region 66 to move sufficiently easily in the longitudinal direction X, in the unfolded and extended state, the length L3 (see FIG. 2) along the longitudinal direction X relative to the length L1 (see FIG. 3) along the width direction Y is preferably 5 times or more, more preferably 10 times or more, preferably 50 times or less, more preferably 20 times or less, and preferably 5 times or more and 50 times or less, more preferably 10 times or more and 20 times or less.
From a similar viewpoint, in the deployed and stretched state, as shown in FIG. 2, the length L3 (see FIG. 2) of the shiftable region 66 along the longitudinal direction X is preferably 60% or more, more preferably 75% or more, and more preferably 95% or less, and more preferably 85% or less, of the length L4 (see FIG. 3) of the leakage preventing cuff 6 along the longitudinal direction X.
The length L3 of the displaceable region 66 is preferably 200 mm or more, more preferably 280 mm or more, and is preferably 500 mm or less, more preferably 360 mm or less.
The length L4 of the leakage preventing cuff 6 is preferably 240 mm or more, more preferably 330 mm or more, and is preferably 600 mm or less, more preferably 500 mm or less.

From the viewpoint of improving the ease of slipping of the shiftable region 66 by conforming to the skin, it is preferable that the mean deviation (MMD) of the friction coefficient of each of the inner surfaces facing each other in the shiftable region 66 of the two nonwoven fabrics 60, 60 is 0.012 or less, more preferably 0.01 or less, and even more preferably 0.008 or less. The lower limit of the mean deviation MMD is preferably as close to 0 as possible, but if it is 0.003 or more, the shiftable region 66 of the leakproof cuff 6 can be given the ability to conform to the skin.

The mean deviation MMD of the friction coefficient is measured by the following method using KESFB4-AUTO-A (product name) manufactured by Kato Tech Co., Ltd., in accordance with the method described in the following publication.
"Standardization and Analysis of Texture Evaluation" by Toshio Kawabata, 2nd Edition, Texture Measurement and Standardization Research Committee of the Japan Textile Machinery Society, July 10, 1980

[Method of measuring mean deviation (MMD) of coefficient of friction]
A test piece measuring 20 cm x 20 cm is taken from the nonwoven fabric constituting the slippage area of the leak-proof cuff or from the nonwoven fabric used for the leak-proof cuff. If a test piece of this size cannot be taken, the size of the test piece may be changed as appropriate. The test piece is attached to a smooth metal test table. At this time, the surface to be contacted with the contactor is attached to the inner surface of the nonwoven fabric of the slippage area. The contactor is pressed against the test piece at the contact surface with a force of 49 cN, and the test piece is moved horizontally for 2 cm at a constant speed of 0.1 cm/sec. A uniaxial tension of 7.3 cN/cm is applied to the test piece. The contactor is the same as the contactor used to measure the surface roughness, and is made by arranging 20 piano wires with a diameter of 0.5 mm, which are bent into a U-shape with a width of 10 mm. The contactor is pressed against the test piece at the contact surface with a force of 49 cN using a weight. The measured value of the mean deviation of the friction coefficient is expressed as the MMD value. This measurement is performed in both the MD and CD directions to obtain MMD _MD and MMD _CD , and the average value is calculated using the following formula (1), which is the mean deviation of the friction coefficient MMD. The MD direction in this measurement is either the longitudinal direction X or the width direction Y, and the CD direction is the direction perpendicular to the MD direction. If a sample test piece can only be taken in either the MD or CD direction, the value in only one direction is used as the mean deviation of the surface roughness MMD.

Mean deviation of friction coefficient MMD
= {(MMD _MD ² + MMD _CD ² )/2} ^1/2 ...(1)

From the viewpoint of making it easier to bring the outer surface of the nonwoven fabric 60 in the displaceable region 66 into close contact with the skin and to further improve the ease of slippage between the inner surfaces of the displaceable region 66, it is preferable that the mean deviation MMD of the friction coefficient of the outer surface of the nonwoven fabric 60 is larger than the mean deviation MMD of the friction coefficient of the inner surface. The mean deviation MMD of the friction coefficient of the outer surface is preferably 1.1 times or more, more preferably 1.5 times or more, and more preferably 3 times or less, and even more preferably 2 times or less, the mean deviation MMD of the friction coefficient of the inner surface. The mean deviation MMD of the friction coefficient of the outer surface is preferably smaller than 0.012, more preferably 0.010 or less, and even more preferably 0.005 or more. The mean deviation MMD of the friction coefficient of the outer surface is measured in the same manner as the method for measuring the mean deviation MMD of the friction coefficient described above. Note that when attaching the test piece to the test stand, it is important to attach it so that the surface that comes into contact with the contactor is the outer surface of the nonwoven fabric in the displaceable region.

From the viewpoint of improving the slippage between the leak-proof cuff 6 and the top sheet 5 and thus preventing the wearer's skin from being rubbed by the leak-proof cuff 6, it is preferable that the mean deviation MMD of the friction coefficient of each of the opposing surfaces of the nonwoven fabric 60 and the top sheet 5 of the leak-proof cuff 6 is 0.012 or less, and more preferably 0.010 or less. The lower limit of the mean deviation MMD is preferably as close to 0 as possible, but if it is 0.005 or more, the wearer's skin and the leak-proof cuff 6 are sufficiently unlikely to rub against each other. Note that the surface of the nonwoven fabric 60 that faces the top sheet 5 refers to the outer surface of the nonwoven fabric 60. The mean deviation MMD of the friction coefficient of the opposing surfaces of the nonwoven fabric 60 and the top sheet 5 is measured in the same manner as the method for measuring the mean deviation MMD of the friction coefficient described above. Note that when attaching the test specimen to the test stand, it is important to attach it so that the surface that comes into contact with the contactor is the opposing surface.

From the viewpoint of further improving the ease of slippage between the leak-preventing cuffs 6 and the top sheet 5, it is preferable that the friction coefficient between the nonwoven fabric 60 of the leak-preventing cuffs 6 and the top sheet 5 is 0.275 or less, and more preferably 0.260 or less. The lower limit of the friction coefficient is preferably as close to 0 as possible, but if it is 0.220 or more, it is possible to sufficiently cause slippage between the leak-preventing cuffs 6 and the top sheet 5. The friction coefficient between the nonwoven fabric 60 of the leak-preventing cuffs 6 and the top sheet 5 is measured by a method similar to that for measuring the friction coefficient between the opposing surfaces of the two nonwoven fabrics 60, 60 in the slippage-possible region 66 described above.

The two nonwoven fabrics 60, 60 in the shiftable region 66 are each formed using a highly flexible nonwoven fabric in order to improve the conformability of the shiftable region 66 to the skin when worn. The flexibility of the nonwoven fabric 60 in the leak-proof cuff 6 can be evaluated by the compression load value. The compression load value in the diaper width direction Y of each nonwoven fabric 60 in the leak-proof cuff 6 is preferably 5 cN or less, and more preferably 4 cN or less. The lower limit of the compression load value is preferably as close to 0 cN as possible, but a value of 1 cN or more can provide sufficient softness to the leak-proof cuff 6. The compression load value in the diaper width direction Y of the nonwoven fabric 60 is measured by the following method.

[Method of measuring compressive load value]
The leak-proof cuff 6 is cut out from the absorbent body 2.
In the shiftable region 66, a piece of nonwoven fabric 60 is cut out into a rectangular shape of 80 mm along the longitudinal direction X of the absorbent main body 2 and 20 mm along the width direction Y. This nonwoven fabric is folded at the center of the longitudinal direction X along a line along the width direction Y, and then further folded at the center of the longitudinal direction X along a line along the width direction Y to obtain a quadruple measurement piece. Wrinkles are smoothed out from the measurement piece, and the non-jointed side in the folded state is clamped with a clip or the like to align the ends.
The obtained quadruple test pieces (sample width; 20 mm) are clamped in the lower chuck of a compression tester (for example, Shimadzu Corporation's autograph compression tester "AG-X") with the width direction vertical, so that 5 mm of the vertical end protrudes from the top of the chuck, and the maximum load shown when compressed at a speed of 10 mm/min with a circular compression plate with a diameter of 30 mm or more attached to the upper side of the compression tester is measured.
The width of the test piece does not have to be less than 20 mm, provided that it can be clamped in the chuck of the testing machine so that 5 mm protrudes from the upper part of the chuck.
The same measurements are carried out for five samples, and the average value is regarded as the compression load value of one sheet of nonwoven fabric 60.

The leak-proof cuff 6 is preferably configured by arranging two sheets of nonwoven fabric 60, 60 with a compression load value of 5 cN or less so as to face each other. The two sheets of nonwoven fabric may be separate nonwoven fabrics that satisfy the compression load value conditions, or may be a single sheet of nonwoven fabric that satisfies the compression load value conditions and is folded in half. In the embodiment shown in FIG. 2, the leak-proof cuff 6 is configured by folding a single sheet of nonwoven fabric 60 in half and arranging the two sheets of nonwoven fabric 60, 60 so as to face each other.

The two nonwoven fabrics 60, 60 in the shiftable region 66 each preferably have a bulk softness of 8 cN or less, and more preferably 5 cN or less. If the leak-proof cuff 6 is formed from such a nonwoven fabric 60, when the leak-proof cuff 6 stands up due to the contraction of the elastic member 63, fine wrinkles are likely to form in the two nonwoven fabrics 60, 60. As a result, the two nonwoven fabrics 60, 60 are more likely to separate from each other, and the shiftable region 66 is more likely to shift in accordance with the skin. The lower limit of the bulk softness of the nonwoven fabric 60 is preferably as close to 0 as possible, but if it is 3 cN or more, the two nonwoven fabrics 60, 60 are sufficiently easy to separate from each other. The bulk softness of the nonwoven fabric 60 is measured by the following method.

[Method of measuring bulk softness]
In an environment of 22°C and 65% RH, a test piece is cut out from the nonwoven fabric 60 of the leak-proof cuff 6, with a length of 150 mm in the CD direction along the orientation direction of the constituent fibers and 30 mm in the MD direction perpendicular to the CD direction. The test piece is stapled at two points, top and bottom, to form a ring shape with a diameter of 45 mm. At this time, the stapler core is made longer in the CD direction. Next, using a tensile tester (for example, Tensilon tensile tester "RTA-100" manufactured by Orientec Co., Ltd.), the ring-shaped test piece is set up in a cylindrical shape on a sample stand, and the maximum load is measured when the ring-shaped test piece is compressed from above with a flat plate approximately parallel to the stand at a compression speed of 10 mm/min. This measurement is performed on any three points cut out from the nonwoven fabric 60 , and the average value of these values is taken as the bulk softness.

The leak-preventing cuff 6 has a pleasant feel against the skin and is less likely to leave marks on the skin caused by the contact between the skin and the leak-preventing cuff 6. From this viewpoint, the deformation amount of the leak-preventing cuff 6 when compressed at 1 kPa is preferably 1 mm or more, and more preferably 1.1 mm or more. The deformation amount when compressed at 1 kPa is measured by the following method.

[Method for measuring deformation amount when compressed to 1 kPa]
The leak-preventing cuffs 6 are removed from the diaper 1, and with the leak-preventing cuffs 6 stretched, a test piece 5 mm wide and 120 mm long in the longitudinal direction X is cut out from the free end 61 to include the free end stretchable part 64, and the test piece is attached to the test stand of the measuring device while stretched to 70 mm in the longitudinal direction X. At this time, the elastic member 63 of the leak-preventing cuffs 6 is positioned at the center of the test stand. A KES compression tester (KESFB3-AUTO-A, manufactured by Kato Tech Co., Ltd.) is used as the measuring device to compress the test piece (free end stretchable part) under the following conditions, and the deformation amount at 1 kPa compression is determined from the stress-strain at that time.
Compression speed: 0.02 mm/s
Compressor: 2 cm ² circular plates

In order to prevent the skin from coming into contact with the top sheet 5 when worn and to improve the ease with which the shiftable region 66 can shift by following the skin, as shown in FIG. 3, in the deployed and extended state, the thickness L6 of the free end stretchable portion 64, 64 of each of the pair of first leak-proof cuffs 6A, 6A is preferably 0.4% or more, more preferably 0.5% or more, and more preferably 5.0% or less, and even more preferably 1.0% or less, of the distance L5 along the width direction Y between the free ends 61, 61 of the pair of first leak-proof cuffs 6A, 6A. The thickness L6 of the free end stretchable portion 64 is measured using a digital microscope (manufactured by Keyence) to measure the cross section of the leak-proof cuff cut in the width direction Y with a sharp blade.

In order to improve the ease of shifting of the shiftable area 66 by conforming to the skin, the thickness L6 of the free end stretchable portion 64 is preferably 0.3 mm or more, more preferably 0.5 mm or more, and is preferably 2.0 mm or less, and more preferably 1.0 mm or less.
From a similar viewpoint, the distance L5 between the free ends 61, 61 of a pair of first leakage-proof cuffs 6A, 6A is preferably 40 mm or more, more preferably 50 mm or more, and is preferably 150 mm or less, and more preferably 80 mm or less.

3, when the absorbent body 4 has slits 44, from the viewpoint of improving the ease with which the shiftable region 66 shifts in accordance with the skin, in the deployed and stretched state, the free end stretchable portion 64 of the first leakage preventing cuff 6A is preferably located outward in the width direction Y from the slits 44. In addition, it is preferable that the shiftable region 66 of the first leakage preventing cuff 6A and the side region 43 of the absorbent main body 2 overlap in the thickness direction.

From the viewpoint of further improving the ease of slippage between the nonwoven fabrics 60, 60 in the slippage possible region 66, as shown in FIG. 4, it is preferable to use two nonwoven fabrics 60, 60 in which the embossed portions 80 in which the constituent fibers are integrated are formed in a state spaced apart from each other in the planar direction. From the viewpoint of further improving the ease of slippage, it is preferable to use a nonwoven fabric whose constituent fibers are mainly composed of propylene random copolymer. Examples of nonwoven fabrics 60 that satisfy these requirements include spunbond nonwoven fabrics, meltblown nonwoven fabrics, and laminated nonwoven fabrics of spunbond layers and meltblown layers. A lubricant such as a surfactant may be added to the nonwoven fabric 60 in order to further improve the ease of slippage.

When forming the leak-proof cuff 6 by arranging two sheets of nonwoven fabric 60, 60 facing each other, from the viewpoint of further improving the ease of slippage between these nonwoven fabrics 60, 60, it is preferable that, as shown in FIG. 4, one surface 6f of the two sheets of nonwoven fabric 60, 60 is an embossed surface with greater undulations than the other surface 6n, and that the embossed surfaces 6f face each other in the slippage area 66. In other words, it is preferable that the recess 91 formed by the embossed portion 80 on one surface 6f is deeper than the other surface 6n. The recess 91 is a depression with the embossed portion 80 at its bottom.

From the same viewpoint as above, the nonwoven fabric 60 preferably has an area ratio of the embossed portion 80, which is the ratio of the total area of the multiple embossed portions 80 to the surface area of one side, of 18% or less, and more preferably 15% or less. The lower limit of the total area ratio is preferably as low as possible, but if it is 8% or more, the ease of slippage between the nonwoven fabrics 60, 60 can be further improved.

The area of each of the embossed portions 80 formed on the nonwoven fabric 60 is preferably 0.1 mm ² or more, more preferably 0.3 mm ² or more, and preferably 0.7 mm ² or less, more preferably 0.5 mm ² or less.

Of the multiple embossed portions 80 in the nonwoven fabric 60, the shortest distance between one embossed portion 80 and another embossed portion 80 located closest to the embossed portion 80 is preferably 0.8 mm or more, more preferably 1.0 mm or more, and preferably 3.0 mm or less, more preferably 2.0 mm or less.

From the viewpoint of allowing the shiftable area 66 to move easily in accordance with the movement of the skin when worn, it is preferable that the inner surfaces of the two nonwoven fabrics 60, 60 facing each other are raised. Examples of raised nonwoven fabrics include those described in JP 2012-092475 A and JP 2014-139357 A.

As materials constituting each part of the diaper 1 of this embodiment, those commonly used in the relevant technical field can be used without any particular restrictions. For example, various types of nonwoven fabrics and perforated films can be used as the top sheet 5. As the leakproof sheet 7, for example, liquid-resistant films and spunbond, meltblown, and spunbond laminated nonwoven fabrics can be used. As each elastic member, rubber threads and the like can be used. As the sheets 31 and 32 for forming the outer body, various types of nonwoven fabrics can be used.

Although the present invention has been described above based on its preferred embodiment, the present invention is not limited to the above embodiment and can be modified as appropriate. For example, the embodiment shown in FIG. 1 relates to a pants-type disposable diaper 1 having an exterior body 3 extending over the abdominal portion F, the crotch portion M, and the back portion R. Alternatively, the present invention may be a pants-type disposable diaper with a split exterior body in which the exterior body is divided into a back sheet member arranged on the back side of the wearer and a abdominal sheet member arranged on the abdominal side, the back sheet member and the abdominal sheet member are joined by a pair of side seals to form a tube, and the absorbent body is fixed between the back sheet member and the abdominal sheet member. The present invention may also be an unfolded disposable diaper instead of a pants-type disposable diaper.

The leak-preventing cuffs 6 of the diaper 1 shown in FIG. 3 have joints 68 with the top sheet 5 arranged outward from the side edges along the longitudinal direction X of the absorbent body 4. As a result, the fixed ends 62 of the first leak-preventing cuffs 6A and the second leak-preventing cuffs 6B are both formed outward from the side edges of the absorbent body 4, but the fixed ends 62 of the first leak-preventing cuffs 6A and the second leak-preventing cuffs 6B may be formed inward from the side edges of the absorbent body 4. Even in this form, when the wearer moves his or her body while wearing the diaper 1, the slipperable area of the leak-preventing cuffs is likely to slip in accordance with the skin. An example of such a form is a form in which the top sheet is arranged to cover the entire skin-facing surface of the absorbent body and to roll down from the side edges of the absorbent body to the non-skin-facing surface side, and the rolled-down portion of the top sheet is joined to the nonwoven fabric 60 of the leak-preventing cuffs 6, and the joints are arranged to be located inward from the side edges of the absorbent body.

The diaper 1 shown in FIG. 3 has a first leak-preventing cuff 6A and a second leak-preventing cuff 6B, but may have either the first leak-preventing cuff 6A or the second leak-preventing cuff 6B. In addition, both the first leak-preventing cuff 6A and the second leak-preventing cuff 6B have a shiftable region 66, but instead, either the first leak-preventing cuff 6A or the second leak-preventing cuff 6B may have the shiftable region 66.

The following notes are further provided with respect to the embodiment of the present invention described above.

＜1＞
A disposable diaper having a longitudinal direction corresponding to the front-to-rear direction of a wearer and a width direction perpendicular to the longitudinal direction, and having a ventral side portion arranged on the ventral side of a wearer when worn, a dorsal side portion arranged on the dorsal side, and a crotch portion located between the ventral side portion and the dorsal side portion, the disposable diaper having a longitudinally elongated absorbent main body including a liquid-permeable top sheet and an absorbent body, and a pair of leakproof cuffs arranged on both sides of the longitudinal direction of the absorbent main body along the longitudinal direction,
The leak-proof cuff is configured to include two opposing nonwoven fabrics, has a free end at one end and a fixed end at the other end of both ends in the width direction, has end fixing portions fixed to the absorbent body near both ends in the longitudinal direction, and has a free end stretchable portion near the free ends in which an elastic member is fixed between the two nonwoven fabrics via an adhesive,
A disposable diaper having a slippage-allowing region between the free end stretchable portion and the fixed end where the two nonwoven fabrics are not joined, wherein the friction coefficient between the opposing surfaces of the two nonwoven fabrics in the slippage-allowing region is 0.275 or less, the length along the longitudinal direction is longer than the length along the width direction, and the length along the width direction is three times or more the length along the width direction of the free end stretchable portion.

＜2＞
The disposable diaper according to <1> above, wherein a coefficient of friction between opposing surfaces of the two nonwoven fabrics constituting the slippage area is 0.260 or less.
＜3＞
The disposable diaper according to <1> or <2>, wherein the two nonwoven fabrics have a mean deviation (MMD) of the coefficient of friction of each of the inner surfaces facing each other in the slippage region of 0.012 or less.
＜4＞
The disposable diaper according to any one of <1> to <3>, wherein the length of the shiftable area along the width direction is 5 times or more larger than the length of the free end stretchable portion along the width direction.
＜5＞
The disposable diaper according to any one of <1> to <4>, wherein, in an unfolded and stretched state, the length of the shiftable region along the longitudinal direction is 60% or more and 95% or less of the length of the leakproof cuff along the longitudinal direction.
＜6＞
The disposable diaper according to any one of <1> to <5>, wherein each of the two nonwoven fabrics in the shiftable region has a compressive load value in the width direction of 5 cN or less.
＜７＞
The disposable diaper according to any one of <1> to <6>, wherein each of the two nonwoven fabrics in the shiftable area has a bulk softness of 8 cN or less.
＜8＞
The disposable diaper according to any one of <1> to <7>, wherein the leakage preventing cuffs have a deformation amount of 1 mm or more when compressed at 1 kPa.
＜9＞
The disposable diaper according to any one of <1> to <8>, wherein the two nonwoven fabrics in the slippage region have a larger mean deviation (MMD) of the coefficient of friction of their outer surfaces than the mean deviation (MMD) of the coefficient of friction of their inner surfaces where the nonwoven fabrics face each other.
＜10＞
The disposable diaper according to any one of <1> to <9>, wherein embossed portions in which constituent fibers are integrated are formed in each of the two nonwoven fabrics and spaced apart from each other in a planar direction, and an area ratio of the embossed portions in each nonwoven fabric is 18% or less.

<11>
The disposable diaper according to any one of <1> to <10>, wherein the two nonwoven fabrics contain a lubricant.
＜12＞
The disposable diaper according to any one of <1> to <11>, wherein the inner surfaces of the two nonwoven fabrics in the shiftable region facing each other are raised.
＜13＞
The disposable diaper according to any one of <1> to <12>, wherein the two nonwoven fabrics have constituent fibers mainly composed of propylene random copolymer.
＜14＞
The disposable diaper according to any one of <1> to <13>, wherein the two nonwoven fabrics each have an embossed portion in which constituent fibers are integrated, one surface of the nonwoven fabric has an embossed surface having greater undulations than the other surface, and the two nonwoven fabrics have embossed surfaces facing each other in the slippage region.
＜15＞
The disposable diaper according to any one of <1> to <14>, wherein in an unfolded and stretched state, a thickness of the free end stretchable portion of each of the pair of leakage preventing cuffs is 0.4% or more and 5.0% or less of a distance along the width direction between the free ends of the pair of leakage preventing cuffs.
＜16＞
The disposable diaper according to <15> above, wherein the free end stretchable portion has a thickness of 0.3 mm or more.
＜１７＞
The disposable diaper according to any one of <1> to <16>, wherein, in a deployed and extended state, a distance between the free ends of the pair of leakage-proof cuffs is 40 mm or more.
＜18＞
The disposable diaper according to any one of <1> to <17>, wherein the elastic member arranged in the free end stretchable portion has a thickness of 300 dtex or more.
＜19＞
The disposable diaper according to any one of <1> to <18>, wherein the number of the elastic members arranged in the free end stretchable portion is two or more.
＜20＞
The disposable diaper according to any one of <1> to <19>, wherein the absorbent body has side regions extending along the longitudinal direction that stand up when the absorbent body is worn.

＜21＞
The disposable diaper according to <20>, wherein in a spread and stretched state, the side regions and the shiftable regions of the absorbent main body overlap in a thickness direction.
＜22＞
The disposable diaper according to <20> or <21>, wherein the absorber has an absorbent core, and has a pair of slits or low basis weight portions extending in the longitudinal direction at inward positions spaced apart from both side edges of the absorbent core at least in the crotch portion, and the side regions are portions of the absorbent main body located outward in the width direction from the flexible portions.
＜23＞
The disposable diaper according to <22>, wherein in an unfolded and extended state, the free end stretchable portion is located outward in the width direction from the flexible portion.
＜24＞
The disposable diaper according to <22> or <23>, wherein the absorbent body has a basis weight of the side regions smaller than a basis weight of a central region sandwiched between the pair of flexible portions.
＜25＞
The disposable diaper according to any one of <1> to <24>, wherein a coefficient of friction between the nonwoven fabric of the leak-proof cuffs and the topsheet is 0.275 or less.
＜26＞
The disposable diaper according to any one of <1> to <25>, wherein the mean deviation (MMD) of the coefficient of friction between the opposing surfaces of the nonwoven fabric and the topsheet of the leak-proof cuffs is 0.012 or less.
＜27＞
The disposable diaper according to any one of <1> to <26>, wherein the fixed ends of the leakage preventing cuffs are formed outward in the width direction from the longitudinal side edges of the absorbent body.
＜28＞
The disposable diaper according to any one of <1> to <26>, wherein the fixed ends of the leakage preventing cuffs are formed widthwise inward of the longitudinal side edges of the absorbent body.
＜29＞
The absorbent body has a pair of first leak-preventing cuffs on both sides in the longitudinal direction thereof, and a pair of second leak-preventing cuffs located outward in the width direction from the pair of first leak-preventing cuffs,
The disposable diaper according to any one of <1> to <28>, wherein one or both of the first leakage preventing cuff and the second leakage preventing cuff are leakage preventing cuffs having the shiftable region.
＜30＞
The disposable diaper according to <29>, wherein both the first leakage preventing cuff and the second leakage preventing cuff have the shiftable area, and the coefficient of friction between the mutually adjacent surfaces of the first leakage preventing cuff and the second leakage preventing cuff is 0.275 or less.

1. Pants-type disposable diapers (disposable diapers)
F: abdominal portion M: crotch portion R: back portion 2: absorbent body 5: top sheet 4: absorbent body 44: slit 6: leak-proof cuff 6A: first leak-proof cuff 6B: second leak-proof cuff 60: nonwoven fabric constituting leak-proof cuff 61: free end 62: fixed end 63: elastic member 64: free end stretchable portion 65: end fixed portion 66: slippage area 80: embossed portion X: longitudinal direction Y: width direction

Claims (7)

A disposable diaper having a longitudinal direction corresponding to the front-to-rear direction of a wearer and a width direction perpendicular to the longitudinal direction, and having a ventral side portion arranged on the ventral side of a wearer when worn, a dorsal side portion arranged on the dorsal side, and a crotch portion located between the ventral side portion and the dorsal side portion, the disposable diaper comprising a longitudinally elongated absorbent main body including a liquid-permeable top sheet and an absorbent body, a pair of first leakproof cuffs arranged on both sides of the longitudinal direction of the absorbent main body along the longitudinal direction , and a pair of second leakproof cuffs located outboard of each of the pair of first leakproof cuffs in the width direction ,
The first leakproof cuff and the second leakproof cuff are each composed of two opposing sheets of nonwoven fabric, and have a free end at one end and a fixed end at the other end of both ends in the width direction, end fixing portions fixed to the absorbent body near both ends in the longitudinal direction, and a free end stretchable portion in which an elastic member is fixed between the two sheets of nonwoven fabric via an adhesive near the free ends,
the first leak-preventing cuff and the second leak-preventing cuff have a slip-able region between the free end stretchable portion and the fixed end where the two nonwoven fabrics are not joined, the slip-able region has a friction coefficient between opposing surfaces of the two nonwoven fabrics of 0.275 or less, a length along the longitudinal direction is longer than a length along the width direction, and the length along the width direction is three times or more the length along the width direction of the free end stretchable portion,
the first leak-preventing cuff and the second leak-preventing cuff have, when the disposable diaper is in an unfolded and extended state, a coefficient of friction between the skin-facing surfaces of the two nonwoven fabrics constituting the first leak-preventing cuff and the second leak-preventing cuff, the skin-facing surfaces of which are located on the skin-facing sides, of 0.275 or less;
The disposable diaper has an embossed portion in which the constituent fibers of the two nonwoven fabrics are integrated, one side is an embossed surface having larger undulations than the other side, and the two nonwoven fabrics have their embossed surfaces facing each other in the slippage area. The disposable diaper according to claim 1, wherein the two nonwoven fabrics in the shiftable area each have a compressive load value in the width direction of 5 cN or less. The disposable diaper according to claim 1 or 2, wherein the two nonwoven fabrics in the shiftable area each have a bulk softness of 8 cN or less. 4. The disposable diaper according to claim 1, wherein the first and second leak -preventing cuffs have a deformation amount of 1 mm or more when compressed at 1 kPa. The disposable diaper according to any one of claims 1 to 4, wherein the absorbent body is configured so that the side regions along the longitudinal direction stand up when worn. 6. The disposable diaper according to claim 5, wherein the absorbent body has an absorbent core and has a pair of slits or low basis weight portions extending in the longitudinal direction at an inner position spaced apart from each of both side edges of the absorbent core at least in the crotch portion, and the side regions are portions of the absorbent body located widthwise outward from the flexible portions. 7. The disposable diaper according to claim 1, wherein a coefficient of friction between the nonwoven fabric and the topsheet of each of the first and second leak-preventing cuffs is 0.275 or less.

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