Patent ID: 12207996

DESCRIPTION OF EMBODIMENTS

Hereinafter, an example of an underpants-type disposable diaper will be described in detail with reference to the accompanying drawings. Note that a dotted pattern portion in the figures indicates an adhesive as bonding means that bonds respective components located on the front surface side and the back surface side thereof, and is formed by solid, bead, curtain, summit, spiral coating of a hot melt adhesive, pattern coating (transfer of the hot melt adhesive in a letterpress method), etc., or application of an elastic member to an outer peripheral surface such as comb gun or sure wrap application instead of or together with the above methods in a fixed part of the elastic member. Examples of the hot melt adhesive include EVA-based, pressure sensitive adhesion rubber-based (elastomer-based), polyolefin-based, and polyester/polyamide-based adhesives, and can be used without any particular limitation. As bonding means that bonds respective components, it is possible to use means by material welding such as heat sealing or ultrasonic sealing.

FIGS.1to7illustrate the underpants-type disposable diaper. This underpants-type disposable diaper (hereinafter also simply referred to as a diaper) has an integral outer body20extending over a front body F and a back body B, and an inner body10fixed to an inner surface of the outer body20to extend from the front body F to the back body B, and the inner body10is obtained by interposing an absorber13between a liquid pervious top sheet11and a liquid impervious sheet12. In manufacturing, after a back surface of the inner body10is bonded to an inner surface (upper surface) of the outer body20by bonding means such as a hot melt adhesive (dotted pattern portion inFIG.2), the inner body10and the outer body20are folded at a center in a front-back direction LD (vertical direction), which is a boundary between the front body F and the back body B, and both side portions thereof are bonded by heat welding, a hot melt adhesive, etc. to form side seal portions21, thereby forming the underpants-type disposable diaper in which a waist opening and a pair of right and left leg openings are formed. The outer body20may be separately provided on the front body F and the back body B.

(Example of Structure of Inner Body)

As illustrated inFIGS.4to6, the inner body10has a structure in which the absorber13is interposed between the top sheet11and the liquid impervious sheet12, and absorbs and retains the excreted liquid passing through the top sheet11by the absorber13. A planar shape of the inner body10is not particularly limited, and is generally a substantially rectangular shape as in the illustrated embodiment.

As the top sheet11that covers the front surface side (skin contact surface side) of the absorber13, a perforated or non-perforated nonwoven fabric, a porous plastic sheet, etc. is preferably used. As a raw material fiber included in the nonwoven fiber, in addition to synthetic fibers such as polyolefin-based fiber such as polyethylene or polypropylene, polyester-based fiber, and polyamide-based fiber, it is possible to use regenerated fibers such as rayon and cupra, and natural fibers such as cotton, and it is possible to use a nonwoven fabric obtained by an appropriate processing method such as a spun lace method, a spun bond method, a thermal bond method, an air through method, or a needle punch method. Among these processing methods, the spun lace method is excellent in flexibility and drapability, and the thermal bond method is excellent in bulkiness and softness. When a plurality of through holes are formed in the top sheet11, urine, etc. can be rapidly absorbed. In the illustrated embodiment, the top sheet11extends up to the back surface side of the absorber13with the side edge portions of the absorber13wrapped around.

As the liquid impervious sheet12covering the back surface side of the absorber13(non-skin contact surface side), a liquid impervious plastic sheet of polyethylene, polypropylene, etc. is used. However, in recent years, a sheet having moisture permeability is preferably used from a viewpoint of preventing stuffiness. As this water blocking and moisture-permeable sheet, for example, it is possible to preferably use a microporous sheet obtained by melt kneading inorganic fine particles such as calcium carbonate in a polyolefin resin such as polyethylene or polypropylene to form a sheet, and then monoaxially or biaxially stretching the sheet. In the illustrated embodiment, the liquid impervious sheet12is folded back to the back surface side on both sides of the absorber13in the width direction WD together with the top sheet11. However, the invention is not limited to such a structure, and another known structure can be adopted.

As the absorber13, it is possible to use a known one, for example, an accumulates of pulp fibers, an assembly of filaments such as cellulose acetate, or one having a nonwoven fabric as a base and a super absorbent polymer mixed and fixed therein as necessary. An overall shape of the absorber13can be an appropriate shape such as a rectangular shape as well as a substantially hourglass shape having a narrowing part narrower than both front and back sides in the crotch part. The absorber13can be provided only in a partial range of the inner body10as long as the absorber13is provided in a range including a back end portion of the inner body10. In a normal case, it is desirable that the absorber13is provided over almost the entire region excluding the front and back end portions of the inner body10.

The absorber13can be wrapped with a wrapping sheet14such as crepe paper having the liquid pervious property and liquid holding property to hold the shape and the polymer as necessary. As the wrapping sheet14, tissue paper, particularly crepe paper, a nonwoven fabric, a polyethylene laminated nonwoven fabric, a sheet with small holes, etc. can be used. However, it is desirable that the wrapping sheet be a sheet through which the super absorbent polymer particles do not pass. When a nonwoven fabric is used instead of the crepe paper, a hydrophilic SMS nonwoven fabric (SMS, SSMMS, etc.) is particularly suitable, and polypropylene, polyethylene/polypropylene composite material, etc. can be used as a material. The basis weight of the wrapping sheet14is desirably 5 to 40 g/m2, particularly desirably 10 to 30 g/m2.

A wrapping mode of the wrapping sheet14can be appropriately determined. However, from a viewpoint of ease of manufacturing and prevention of leakage of super absorbent polymer particles from edges of front and back end portions, a preferable mode is that the absorber13is wound in a tubular shape to surround front and back surfaces and both side surfaces, front and back edge portions are projected from the front and back of the absorber13, and wound and overlapped parts and overlapping parts of front and back protrusions are bonded by bonding means such as a hot melt adhesive or material welding.

Rising gathers90are provided on both sides of the inner body10in the width direction WD. The rising gathers90have rising parts94rising from side portions of the inner body10, and the rising parts94are in contact with a range from a groin portion of the wearer to a gluteal region through a leg circumference to prevent side leakage. More specifically, as illustrated inFIGS.5and6, each of the rising gathers90of the illustrated example has a gather fixed portion91fixed to a side portion of a back surface of the inner body10, a main unit part92extending from the gather fixed portion91to a side portion of a front surface of the inner body10through a side of the inner body10, a fallen portion93formed by fixing front and back end portions of the main unit part92to the side portion of the front surface of the inner body10in a fallen state, and a rising part94formed by not fixing between fallen portions93. Further, these parts have a two-layered structure formed by folding back the gather sheet95, and between the layers, an elongated gather elastic member96is arranged at a tip portion of the rising part94, etc. With such a structure, the rising part94of the rising gather90rises to come into contact with a skin of the wearer. As the gather sheet95, a water repellent nonwoven fabric is preferably used.

Examples of the gather elastic member96include a commonly used material such as polystyrene-based rubber, polyolefin-based rubber, polyurethane-based rubber, polyester-based rubber, polyurethane, polyethylene, polystyrene, styrene-butadiene copolymer, silicone, or polyester. Further, in order to make it difficult to see from the outside, it is preferable that the thickness is 925 dtex or less, the tension is 150 to 350%, and the interval is 7.0 mm or less. Note that as the gather elastic member96, in addition to a thread-shaped member as in the illustrated embodiment, it is possible to use a tape-shaped member having a certain width.

As a row material fiber included in the gather sheet95, similarly to the top sheet11, in addition to synthetic fibers such as polyolefin-based fiber such as polyethylene or polypropylene, polyester-based fiber, and polyamide-based fiber, it is possible to use regenerated fibers such as rayon and cupra, and natural fibers such as cotton, and it is possible to use a nonwoven fabric obtained by an appropriate processing method such as a spun bond method, a thermal bond method, an air through method, or a needle punch method. In particular, in order to prevent stuffiness, it is preferable to use a nonwoven fabric having a low basis weight and excellent air permeability. Further, with regard to the gather sheet95, in order to prevent the permeation of urine, etc., prevent the rash, and enhance the texture (dry feeling), it is desirable to use a water-repellent nonwoven fabric coated with a silicone-based, paraffin metal-based, alkylchromic chloride-based water repellent agent, etc.

(Example of Structure of Outer Body)

As illustrated inFIGS.4to6, the outer body20has a two-layered structure including a pressing sheet20A and a back sheet20B, each of which is made of a nonwoven fabric, etc., elastic members24to27are provided between the pressing sheet20A and the back sheet20B, and between nonwoven fabrics of a folded part20C formed by folding back the back sheet20B toward the internal surface side at the waist opening edge, and the outer body20contracts by the contraction force of the elastic members24to27in a natural length state, so that the outer body20is given elasticity. A planar shape of the outer body20is substantially an hourglass shape as a whole by concave around-leg lines29formed to form leg openings at both sides in the middle in the front-back direction LD.

The outer body20of the illustrated embodiment includes, as the elastic member, in a spread shape illustrated inFIGS.1and2, a waist portion elastic member24arranged near a waist opening23and a plurality of lower waist portion elastic members25arranged along the width direction WD at an interval in the vertical direction in the front body F and the back body B. Further, in each of the front body F and the back body B, separately from the lower waist portion elastic members25, the outer body includes a plurality of curved elastic members26and27which are directed from one side seal portion21to the crotch part along one leg opening, traverse the crotch part, and extend while curving in a pattern reaching the other side seal portion21along the other leg opening, and are arranged at an interval without intersecting each other. These elastic members24to27are fixed in a state of being extended at a predetermined stretch rate along an extending direction thereof. Note that in the outer body20, so-called around-leg elastic members that are continuous from the side seal portions of the front body F to the side seal portions of the back body B along the around-leg lines29are not provided.

The waist portion elastic member24is an elongated elastic member such as a plurality of rubber threads arranged at an interval in the vertical direction near a waist opening edge within a range of the side seal portions21where the front body F and the back body B are bonded, and is used to wear the diaper on the body by giving a stretching force to tighten the waist of the body. As the waist portion elastic member24, the rubber threads are used in the illustrated example. However, for example, it is possible to use a tape-shaped stretchable member. In addition, even though the waist portion elastic member24of the illustrated embodiment is interposed between the nonwoven fabrics of the folded part20C of the back sheet20B in the waist portion, the waist portion elastic member24may be interposed between the pressing sheet20A and the back sheet20B.

The lower waist portion elastic member25is an elongated elastic member such as rubber threads arranged at an interval in the vertical direction over a range roughly from an upper portion to a lower portion in the side seal portions21, and is used to apply a stretching force in the width direction WD to each of around-waist parts of the front body F and the back body B, so that the diaper is brought into close contact with the body. Note that a boundary between the waist portion elastic member24and the lower waist portion elastic member25may not be clear. For example, among the elastic members arranged in the width direction WD in the front body F and the back body B at intervals in the vertical direction, even though the number may not be specified, it is sufficient that some of the elastic members on the upper portion side function as the waist portion elastic member, and the remaining elastic members function as the lower waist portion elastic member.

In the back body B, the dorsal side curved elastic member26, which is arranged separately from the lower waist portion elastic member25, is an elongated elastic member such as rubber thread, and is arranged along a predetermined curve. The dorsal side curved elastic member26may be one member and is preferably a plurality of members. In the illustrated example, the dorsal side curved elastic member26is an elongated elastic member of four rubber threads, etc., and these dorsal side curved elastic members26are arranged at intervals without intersecting each other. The dorsal side curved elastic member26is not arranged substantially in a bundle with a few elastic members closely spaced, and three or more, preferably four or more dorsal side curved elastic members26are arranged at intervals of about 3 to 20 mm, preferably 6 to 16 mm to form a predetermined stretchable zone.

In the front body F of the outer body20, the ventral side curved elastic member27, which is arranged separately from the lower waist portion elastic member25, is an elongated elastic member such as rubber thread, and is arranged along a predetermined curve. The ventral side curved elastic member27may be one member and is preferably a plurality of members. In the illustrated example, the ventral side curved elastic member27is four thread-shaped elastic members, and these ventral side curved elastic members27are arranged at intervals without intersecting each other. The ventral side curved elastic member27is not arranged substantially in a bundle with a few elastic members closely spaced, and three or more, preferably four or more dorsal side curved elastic members26are arranged at intervals of about 3 to 20 mm, preferably 6 to 16 mm to form a predetermined stretchable zone.

Note that as illustrated inFIG.2, after continuously fixing the lower waist portion elastic member25and the curved elastic members26and27arranged in the front body F and the back body B to the outer body20during manufacturing, an intermediate portion (part surrounded by a two-dot chain line in the figure) of a part overlapping the absorber13in the width direction WD can be finely cut in a predetermined cutting pattern to form a non-contraction part on which a contraction force does not act, and a part laterally extending from the non-contraction part can be set to a contraction part on which the contraction force acts (that is, a part in which the lower waist portion elastic member25and the curved elastic members26and27are continuously left). In this way, it is possible to prevent unnecessary contraction of the inner body (in particular, the absorber13) in the width direction WD. Naturally, the lower waist portion elastic member25and the curved elastic members26and27can be continuously arranged across the inner body10.

As can be seen from this example, the contraction part in a site where the elastic members24to27are arranged becomes the stretchable region. The stretchable region may be provided only on the waist side of the back end portion of the absorber13in the back body B, and may be provided in each portion as in the illustrated example or another known example.

For example, the above-mentioned outer body20can be manufactured by technologies described in JP H4-28363 A and JP H11-332913 A. In addition, to cut the curved elastic members26and27on the inner body10and make the curved elastic members26and27discontinuous, cutting methods described in JP 2002-35029 A, JP 2002-178428 A, and JP 2002-273808 A are preferably adopted.

Unlike the illustrated example, the curved elastic members26and27may be provided only on one of the front body F and the back body B. In addition, when the curved elastic members26and27are provided on both the front body F and the back body B, it is possible to adopt a mode (not illustrated) in which a part or all of a group of the curved elastic members27arranged on the front body F side intersects with a part or all of a group of the curved elastic members26arranged on the back body B. However, as in the illustrated example, it is preferable to adopt a mode in which the group of the curved elastic members27arranged on the front body F side does not intersect with the group of the curved elastic members26arranged on the back body B, and the groups are spaced apart in the vertical direction in the intermediate portion in the front-back direction LD, particularly at a position slightly biased to the front body F.

Further, the curved elastic members26and27may not be entirely curved, and may have a partially linear part.

Stretch rates of the elastic members24to27during fixing can be appropriately determined. However, in the case of using for normal adults, the stretch rate of the waist portion elastic member24can be set to about 160 to 320%, the stretch rate of the lower waist portion elastic member25can be set to about 160 to 320%, and the stretch rates of the curved elastic members26and27can be set to about 230 to 320%.

(Cover Sheet)

As illustrated inFIGS.1and4, to cover the front and back end portions of the inner body10attached on the inner surface of the outer body20and prevent leakage from front and back edges of the inner body10, cover sheets50and60may be provided. The illustrated embodiment will be more specifically described. The cover sheet50on the front side extends over the entire part in the width direction WD from the inner surface of the folded part20C at a waist side end portion in the inner surface of the front body F to a position overlapping the front end portion of the inner body10, and the cover sheet60on the back side extends over the entire part in the width direction WD from the inner surface of the folded part20C at a waist side end portion in the inner surface of the back body B to a position overlapping the back end portion of the inner body10. When a slight non-adhesive part is provided over the entire part in the width direction WD (may be only a center portion) at a crotch side edge portion of each of the cover sheets50and60, the adhesive does not stick out, and this part can be made slightly rise from the top sheet to function as a leak prevention wall.

When the cover sheets50and60are separately attached as in the illustrated embodiment, there is an advantage that a degree of freedom in selecting a material is increased. However, there is a demerit that the number of materials and manufacturing processes is increased. For this reason, the folded part20C obtained by folding back the outer body20on the inner surface of the diaper can be extended to the part overlapping the inner body10to form a part equivalent to the above-described cover sheets50and60. Note thatFIG.3illustrates an adhesive part72of the cover sheets50and60to the inner surface of the outer body20.

(Dorsal Side Barrier)

On the inner surface of the underpants-type disposable diaper, a barrier sheet71is provided to extend from a position on the front side of the back end of the absorber13to the back side thereof and extend outward in the width direction from positions of the both side edges of the absorber13in the width direction WD. Though, as the barrier sheet71, a dedicated sheet may be arranged, it is desirable to form the barrier sheet71by extending the cover sheet60to the crotch side as in the illustrated example. In the barrier sheet71, a dimension of a part extending to the front side of the back end of the absorber13can be appropriately determined, and may be set to, for example, about 5 to 10% of a maximum length L of the product (about 40 to 80 mm in the case of an adult disposable diaper). A front end of the barrier sheet71can be located on the crotch side of the side seal portion21.

As can be seen from the adhesive part72of the barrier sheet71(cover sheet60) illustrated inFIG.3, the barrier sheet71includes a free part73not bonded to a member on the back surface side and a fixed part74bonded to the member on the back surface side (the pressing sheet20A and the folded part20C in the illustrated example). The free part73is a part that is located at least in a middle of a part overlapping the absorber13in the width direction WD in the barrier sheet71and is continuous from a front edge to a middle in the front-back direction LD in the barrier sheet71. In addition, the fixed part74surrounds a back side of the free part73and both sides of the free part73in the width direction WD, and width direction inner edges of parts located on both sides of the free part73in the width direction in the fixed part74are adjacent to width direction outer sides of the side edges of the inner body10and the side edges of the inner body10. As illustrated inFIGS.4and9, the barrier sheet71having the free part73and the fixed part74forms a pocket-shaped dorsal side barrier70having an inlet that opens on the crotch side. As illustrated inFIG.13, in the fixed part74, width direction inner edges of parts located on both sides of the free part73in the width direction WD are located on both sides in the width direction on the inner body10(located on the rising gather90in the illustrated example, and may be located on the top sheet11as long as the free part73is formed).

A dimension73W of the free part73in the width direction WD may be substantially the same or narrower than a dimension10W of the inner body10in the width direction WD. The dimension of the free part73in the width direction WD is equal to a width of an inlet of the dorsal side barrier70, and thus a leakage prevention property becomes poor when the dimension is excessively narrow. Thus, the dimension is preferably 70 to 90% of the dimension10W of the inner body10in the width direction WD.

A dimension73L of the free part73in the front-back direction LD may be appropriately determined, and may be the same, longer than, or shorter than a dimension70L of a region in which the barrier sheet71and the inner body10overlap in the front-back direction LD. When the dimension73L of the free part73in the front-back direction LD is long, a pocket of the dorsal side barrier70becomes deep. However, when the dimension is excessively long, the barrier sheet71is likely to be irregularly deformed, and thus it is preferable that the part is located within a range of ±10 mm before and after a back edge of the absorber13.

Characteristically, a torsion hardness (measurement method will be described later) of a predetermined part including the back end portion of the absorber13is set to 0.18 to 0.32 N·cm/cm, particularly preferably 0.22 to 0.28 N·cm/cm. When the torsion hardness of the predetermined part including the back end portion of the absorber13is within this range, as illustrated inFIG.9, a part of the absorber13overlapping the free part73of the barrier sheet71gently bulges outward to circumscribe bulges of both gluteal regions, rippling deformation or bending deformation biting into an intergluteal cleft is less likely to occur, and contraction in the width direction WD becomes smaller. Further, the free part73of the barrier sheet71is raised on the opposite side from the bulge of the absorber13based on the strong absorber13that gently bulges outward to form the pocket-shaped dorsal side barrier70having the inlet that opens on the crotch side. Therefore, the inlet of the dorsal side barrier70is easily opened wider.

On the other hand, when the torsion hardness of the predetermined part including the back end portion of the absorber13is excessively weak, as illustrated inFIG.14, a torsion force applied by movement of the legs and a contraction force in the width direction WD by the elastic member are applied to the part, so that rippling deformation or bending deformation biting into the intergluteal cleft occurs, and contraction in the width direction WD tends to increase. Further, in this case, the absorber13serving as a base of the barrier sheet71is less likely to bulge outward, and the width direction dimension of the free part73of the barrier sheet71becomes excessive, so that the free part73of the barrier sheet71becomes difficult to rise or is deformed in an irregular wavy pattern, and a situation in which the inlet or an inner space of the dorsal side barrier70becomes unnecessarily narrow is likely to occur.

As described above, when the part of the absorber13overlapping the free part73of the barrier sheet71easily contracts in the width direction WD, the situation in which the inlet or the inner space of the dorsal side barrier70becomes unnecessarily narrow is likely to occur. Therefore, it is preferable that the overlapping part between the free part73of the barrier sheet71and the absorber13does not have the stretchable region as in the outer body20of the illustrated example.

The absorber13is not limited by the material, etc. as long as the torsion hardness of the predetermined part including the back end portion is within the above-mentioned range. However, in the case of an aggregate of pulp fibers and super absorbent polymer particles, it is preferable that in the predetermined part including at least the back end portion, a total basis weight of the pulp fibers and the super absorbent polymer particles is 350 to 600 g/m2, a weight ratio of the super absorbent polymer particles to the pulp fibers is 40 to 60%, and a thickness is 6 to 12 mm. In this way, by making the pulp basis weight sufficiently high and having a sufficient thickness, it is possible to obtain the absorber13having the above-mentioned torsion hardness.

As described above, in a case where the free part73of the barrier sheet71rises on the opposite side from the bulge of the absorber13based on the strong absorber13that gently bulges outward, even when the elastic member is not provided, the free part73of the barrier sheet71is slightly pushed toward the center side in the width direction WD, and thus naturally easily rises to the opposite side from the bulge of the absorber13. Therefore, as in the example illustrated inFIGS.4,8and9, it is also preferable not to provide a stretchable part in the width direction WD contracted by the elastic member75in the free part73of the barrier sheet71, thus simplifying the structure and thereby reducing the cost. Naturally, as illustrated inFIGS.11and12, the elastic member75may be attached to the front end portion of the free part73of the barrier sheet71to raise the free part73by a contraction force of the elastic member75.

In particular, in the case of not having the elastic member75for raising the free part73of the barrier sheet71, when the barrier sheet71appears to merge into the surrounding member, for example, in a case where the free part73of the barrier sheet71is improperly bent, a user may not notice this fact during use, and there is concern that the leakage prevention effect may be insufficient. Therefore, as illustrated inFIGS.1and3, it is also preferable to provide a mark79at the front end portion in the free part73of the barrier sheet71so that the presence of the barrier sheet71can be easily noticed. The mark79may be a straight line as in the illustrated example, or may be a pattern or any shape such as a mark or a character. The mark79may be provided by attaching a member to which the mark79is added or a member formed in the shape of the mark79to the free part73. However, it is desirable to provide the mark79by directly printing the mark79on the free part73.

In addition, in particular, in the case of not having the elastic member75for raising the free part73of the barrier sheet71, there is concern that rising of the free part73of the barrier sheet71may be insufficient. In this case, as illustrated inFIGS.1and9, it is preferable that the barrier sheet71is provided to pass over the rising gathers90, and at least a part of the barrier sheet71is arranged to overlap the rising parts94of the rising gathers90. In this way, the free part73of the barrier sheet71easily rises by the rising parts94of the rising gathers90. In this case, a part of the barrier sheet71overlapping the rising gathers90may not be bonded to surfaces of the rising gathers90as illustrated inFIGS.1and9or may be bonded thereto as illustrated inFIG.13. Naturally, as illustrated inFIG.10, the free part73of the barrier sheet71may not be located at the rising parts94of the rising gathers90(the front end of the barrier sheet71is located at the fallen portions93of the rising gathers90).

The material of the barrier sheet71is not particularly limited, and it is desirable to use the same material as that of the gather sheet95. In particular, in the case of not having the elastic member for raising the free part73of the barrier sheet71, when at least an outer surface of the barrier sheet71is a nonwoven fabric of fibers made of polyethylene resin, the barrier sheet71easily adheres to the skin, and rising of the free part73of the barrier sheet71is promoted, which is preferable. In addition, for the same reason, it is preferable that the barrier sheet71has high rigidity.

<Effect Confirmation Experiment>

Samples of the underpants-type disposable diaper illustrated inFIGS.1to9, which were common except that the torsion hardness of the predetermined part including the back end portion of the absorber was different therebetween, were manufactured, and a state of the barrier sheet was observed with a dummy doll wearing each of the samples. The torsion hardness and the observation result of each sample are as follows.

(Sample 1)

Torsion hardness: 0.22 N·cm/cmAs in the example illustrated inFIG.9, the free part of the barrier sheet rose to the opposite side from the bulge of the absorber, and the inlet of the dorsal side barrier reliably opened to the crotch side.
(Sample 2)Torsion hardness: 0.28 N·cm/cmAs in the example illustrated inFIG.9, the free part of the barrier sheet rose to the opposite side from the bulge of the absorber, and the inlet of the dorsal side barrier reliably opened to the crotch side.
(Sample 3)Torsion hardness: 0.15 N·cm/cmAs in the example illustrated inFIG.14, contraction of the absorber in the width direction became large, and the absorber serving as the base of the barrier sheet was less likely to bulge outward. As a result, the inlet of the dorsal side barrier collapsed and became narrow.
(Sample 4)Torsion hardness: 0.35 N·cm/cmThe absorber was not deformed as in the example illustrated inFIG.14. However, the absorber hardly gently bulged outward, and the inlet of the dorsal side barrier was narrower than that of Samples 1 and 2.
<Description of Terms Used Herein>

In a case where the following terms are used in the specification, those have the following meanings unless otherwise specified in the specification.“Front-back direction” means a direction (vertical direction) indicated by the reference character LD in the figure, “width direction” means a direction (right-left direction) indicated by WD in the figure, and the front-back direction and the width direction are orthogonal to each other.“Spread state” means a flatly spread state without contraction or slack.“Stretch rate” means the value when the natural length is taken as 100%. For example, a stretch rate of 200% is synonymous with a stretch magnification of 2 times.“Basis weight” is measured as follows. After the sample or test piece is preliminary dried, it is allowed to stand in a test room or apparatus under normal conditions (the test location is at a temperature: 23±1° C., relative humidity: 50±2%) until the constant mass. The preliminary drying is to make the sample or test piece be constant mass in an environment of a temperature of 100° C. Note that the fibers of an official moisture regain of 0.0% do not need preliminary drying. From a test piece having a constant weight, a sample having a size of 100 mm×100 mm is cut out using a template for sampling (100 mm×100 mm) per square meter. The sample is weighed and the weight is multiplied by 100 into the weight per square meter. The resulting value is defined as the basis weight.“Torsion hardness” means a value measured by the following test. In order to apply as little force as possible to the absorber, a part having a front-back direction dimension 60 mm×a width direction dimension 140 mm is cut out to include the back end of the absorber, and the whole is wrapped with a single layer of crepe paper (basis weight 15 g/m2) to manufacture a specimen. Using a torsion tester (KES-YN-1-B, manufactured by KATO TECH CO., LTD.), both end portions of the specimen in the width direction are pinched with a chuck having a chuck distance of 110 mm, and a maximum load (torsion hardness) when twisted by 70 degrees around a longitudinal center axis is measured. Conditions of the tester are SENS (recording sensitivity): 10, torsion angle: 7, CONTROL: 7, speed: 12 cm/s. Note that the test is performed on five specimens, and an average value is used as a measured value of the torsion hardness.“Thickness” of the absorber is measured using a thickness measuring instrument of OZAKI MFG. CO., LTD. (PEACOCK, digital type, model FFD-7 (measurement range 0 to 20 mm)) by making the sample and the thickness measuring instrument horizontal.“Thickness” other than the above thickness is automatically measured using an automatic thickness measuring instrument (KES-G5 Handy Compression Measurement Program) under the conditions of load: 0.098 N/cm2and pressurized area: 2 cm2.“Water absorption capacity” is measured according to JIS K7223-1996 “Testing method for water absorption capacity of super absorbent polymers”.“Water absorption rate” is the “time that elapses before the end point” measured in accordance with JIS K7224-1996 “Testing method for water absorption rate of super absorbent polymers” has been carried out using 2 g of superabsorbent polymer and 50 g of physiological saline solution.When environmental conditions in tests and measurements are not described, the tests and measurements shall be carried out in a test room or apparatus under normal conditions (the test location is at a temperature: 23±1° C., relative humidity: 50±2%).The dimension of each part means the dimension in the spread state, not the natural length state, unless otherwise specified.

INDUSTRIAL APPLICABILITY

The invention can be used for the underpants-type disposable diaper as in the above example.

REFERENCE SIGNS LIST

10INNER BODY11TOP SHEET12LIQUID IMPERVIOUS SHEET13ABSORBER14WRAPPING SHEET20OUTER BODY20C FOLDED PART21SIDE SEAL PORTION24WAIST PORTION ELASTIC MEMBER25LOWER WAIST PORTION ELASTIC MEMBER26,27CURVED ELASTIC MEMBER26DORSAL SIDE CURVED ELASTIC MEMBER27VENTRAL SIDE CURVED ELASTIC MEMBER29AROUND-LEG LINE90RISING GATHER91GATHER FIXED PORTION92MAIN UNIT PART93FALLEN PORTION94RISING PART95GATHER SHEET96GATHER ELASTIC MEMBERF FRONT BODYB BACK BODYLD FRONT-BACK DIRECTIONWD WIDTH DIRECTION70DORSAL SIDE BARRIER71BARRIER SHEET73FREE PART74FIXED PART75ELASTIC MEMBER79MARK