Absorbent article

Abstract

To provide an absorbent article capable of suppressing leakage from a backside sheet while suppressing generation of stuffiness in a worn state.SOLUTION: An absorbent article 1 comprising an absorber 20, and a moisture-permeable backside sheet 40 disposed on a non-skin-facing surface side of the absorber 20, comprises a liquid resistant area 70 for preventing transfer of liquid from the absorber 20 to the backside sheet 40, between the absorber 20 and the backside sheet 40. The liquid resistant area 70 includes a pair of outer liquid-resistant areas 71 located laterally Y outward the absorbent article 1, and a pair of inner liquid-resistant areas 72 located laterally Y inward the outer liquid resistant areas 71. The basis weight of the outer liquid-resistant areas 71 is higher than that of the inner liquid-resistant areas 72. A space 80 defined by the backside sheet 40 and the absorber 20 is formed between the pair of inner liquid-resistant areas 72.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an absorbent article. [Background technology]

[0002] Background Art Known absorbent articles, including sanitary napkins and disposable diapers, include an absorbent body, leak-proof cuffs arranged on both side edges of the absorbent body, and a backsheet arranged on the non-skin-facing side of the absorbent body.

[0003] For example, Patent Document 1 describes a disposable diaper having an absorbent body including an absorbent core, leak-proof cuffs located on both sides of the absorbent body in the longitudinal direction, and a liquid-impermeable back sheet located on the non-skin-facing side of the absorbent body. In the diaper described in this document, the base ends of the leak-proof cuffs are joined by the absorbent body and the back sheet.

[0004] Patent Document 2 describes a pants-type disposable diaper having an absorbent body, a liquid-impermeable back sheet located on the non-skin facing side of the absorbent body, and a three-dimensional gather consisting of a three-dimensional gather sheet. In the diaper described in this document, the base end of the three-dimensional gather is located on the non-skin facing side of the back sheet. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2006-247363 A [Patent Document 2] JP 2018-161266 A Summary of the Invention [Problem to be solved by the invention]

[0006] In order to prevent the absorbent article from becoming stuffy when worn, a moisture-permeable back sheet is often used. When a moisture-permeable back sheet is used, due to its moisture permeability, some measure is required to reliably prevent liquid leakage. Therefore, an object of the present invention is to improve the ability to prevent leakage of liquid from the backsheet in an absorbent article having a moisture-permeable backsheet. [Means for solving the problem]

[0007] The present invention relates to an absorbent article comprising an absorbent body and a moisture-permeable backsheet arranged on the non-skin-facing side of the absorbent body. In one embodiment, it is preferable that a liquid-resistant portion is provided between the absorbent body and the back sheet for preventing the migration of liquid from the absorbent body toward the back sheet. In one embodiment, it is preferable that the liquid-resistant regions have a pair of outer-side liquid-resistant regions located on the outer side in the lateral direction of the absorbent article, and a pair of inner-side liquid-resistant regions located laterally inward of the outer-side liquid-resistant regions. In one embodiment, the pair of inner fluid-resistant regions are preferably spaced apart from each other in the lateral direction. In one embodiment, the outer liquid resistant region preferably has a basis weight higher than that of the inner liquid resistant region. In one embodiment, it is preferred that the skin-facing surface of the back sheet is coated with adhesive only in the area that is in direct contact with the liquid-resistant portion, thereby bonding the back sheet to the liquid-resistant portion. In one embodiment, it is preferable that a space defined by the back sheet and the absorbent body is formed between the pair of inner liquid-resistant regions. Effect of the Invention

[0008] According to the present invention, there is provided an absorbent article that can suppress the occurrence of stuffiness when worn and can also suppress leakage from the back sheet. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a plan view of a pants-type disposable diaper, which is one embodiment of the absorbent article of the present invention, in an unfolded and fully stretched state as viewed from the skin-facing side. [Diagram 2] FIG. 2 is a cross-sectional view of the diaper shown in FIG. 1 taken along line II-II. [Diagram 3] FIG. 3 is an enlarged view of a main portion of FIG. [Figure 4] FIG. 4 is an exploded perspective view of the absorbent core of the diaper shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings. Fig. 1 shows a pants-type disposable diaper (hereinafter, simply referred to as "diaper") 1, which is one embodiment of the absorbent article of the present invention.

[0011] The diaper 1 shown in Fig. 1 has a longitudinal direction X corresponding to the front-to-back direction of a wearer and a lateral direction Y perpendicular to the longitudinal direction X. The diaper 1 has a ventral portion F located on the ventral side of the wearer when the diaper 1 is worn, a dorsal portion R located on the dorsal side, and a crotch portion M located between the ventral portion F and the dorsal portion R. When the diaper 1 is worn, the crotch portion M is disposed opposite excretory parts such as the urethra and anus of the wearer.

[0012] The diaper 1 comprises an absorbent body 20, a backsheet 40 arranged on the non-skin facing side of the absorbent body 20, and an exterior body 60 arranged on the non-skin facing side of the backsheet 40. In this specification, the "skin-facing side" refers to the side of a diaper or its constituent members (e.g., absorbent body) that faces the wearer's skin when the diaper is worn, and the "non-skin-facing side" refers to the side that faces away from the wearer's skin when the diaper is worn.

[0013] The exterior body 60 is disposed continuously over the entire areas of the abdominal portion F, the crotch portion M, and the back portion R. The peripheral edge of the exterior body 60 forms the outline of the diaper 1. The exterior body 60 is formed by laminating an inner layer sheet 61 and an outer layer sheet 62. The outer layer sheet 62 forms the outermost layer of the diaper 1. The outer layer sheet 62 is directly bonded to the inner layer sheet 61. The inner layer sheet 61 is directly bonded to the surface of the back sheet 40 opposite to the surface facing the leakproof cuffs 50. The inner layer sheet 61 and the outer layer sheet 62 are bonded to each other by a known bonding means such as an adhesive, heat sealing, ultrasonic sealing, etc.

[0014] In the exterior body 60, both side portions 1F, 1R along the longitudinal direction X of the exterior body 60 in the ventral portion F and the dorsal portion R are joined together in a palm-to-palm manner by a known joining means such as adhesive, heat sealing, ultrasonic sealing, etc. As a result, the diaper 1 is formed with a pair of side seal portions (not shown), a waist opening (not shown) through which the wearer's torso passes, and a pair of leg openings (not shown) through which the wearer's lower legs pass.

[0015] A plurality of waist elastic members 63A are arranged in the waist opening region 1W, which is the end region of the exterior body 60 in the longitudinal direction X, sandwiched between an inner sheet 61 and an outer sheet 62. The waist elastic members 63A are made of rubber thread or the like, and are fixed between the sheets 61, 62 in a state in which they are stretchable in the lateral direction Y. When the diaper 1 is worn, the waist elastic members 63A contract to form waist gathers in the waist opening region 1W. The waist region 1D is located inward of the waist opening region 1W of the diaper 1 in the longitudinal direction X. A plurality of waist elastic members 63B are arranged in the waist region 1D. The waist elastic members 63B are fixed between the sheets 61, 62 in a state in which they are stretchable in the lateral direction Y. When the diaper 1 is worn, the waist elastic members 63B contract to form waist gathers in the waist region 1D. In this specification, the "waist region" refers to the region between the waist opening region 1W and the crotch part M.

[0016] Both side portions of the exterior body 60 are constricted inward in the crotch portion M in the lateral direction Y. A plurality of leg elastic members 64 sandwiched between an inner layer sheet 61 and an outer layer sheet 62 are disposed on both side portions of the crotch portion M. The leg elastic members 64 are fixed between the sheets 61, 62 in a state in which they are stretchable in the lateral direction Y. When the diaper 1 is worn, the leg elastic members 64 contract to form leg gathers (not shown) in the crotch portion M.

[0017] The absorbent body 20 has a function of absorbing and retaining excrement such as urine. The absorbent body 20 has a long shape in the longitudinal direction X, and extends in the longitudinal direction X from the ventral portion F to the dorsal portion R with its longitudinal direction coinciding with the longitudinal direction X. The absorbent body 20 includes an absorbent core 21. The absorbent core 21 may be, for example, a stack or sheet containing water-absorbent fibers. The absorbent core 21 may also be a stack containing water-absorbent fibers and water-absorbent polymer particles. The absorbent core 21 may also be a sheet material formed by holding water-absorbent polymer particles between two sheets containing water-absorbent fibers. Examples of absorbent fibers include natural fibers such as wood pulp, such as softwood pulp and hardwood pulp, and non-wood pulp, such as cotton pulp and hemp pulp; modified pulp, such as cationic pulp and mercerized pulp (all of these are cellulosic fibers); and hydrophilic synthetic fibers. These can be used alone or in combination of two or more.

[0018] 2, the entire surface of the absorbent core 21, including the skin-facing surface and the non-skin-facing surface, is covered with a core wrap sheet 22. As the core wrap sheet 22, for example, a tissue paper made of hydrophilic fibers or a liquid-permeable nonwoven fabric can be used. Of the core wrap sheet 22, at least the portion located on the non-skin facing surface of the absorbent core 21 is preferably made of a spunbond-meltblown-spunbond (SMS) composite nonwoven fabric. Since an SMS composite nonwoven fabric exhibits liquid permeability while also having a moderate resistance to liquid penetration, by disposing a core wrap sheet 22 provided with such a nonwoven fabric on the non-skin facing surface of the absorbent core 21, the migration of liquid from the absorbent body 20 to the backsheet 40 can be more effectively suppressed.

[0019] The back sheet 40 is located on the non-skin facing side of the absorbent body 20. The back sheet 40 is moisture permeable, so that steam generated from liquid absorbed in the absorbent body 20 can be easily dissipated from the back sheet 40 to the outside of the diaper 1. As a result, moisture is less likely to accumulate inside the diaper 1, and stuffiness when worn can be suppressed. For example, a moisture-permeable film, a water-repellent nonwoven fabric, or a laminate of a moisture-permeable film and a water-repellent nonwoven fabric can be used as the back sheet 40. The back sheet 40 may have a single-layer structure, or a laminate structure in which one or more types of layers are laminated.

[0020] In order to prevent the diaper 1 from becoming stuffy when worn, the back sheet 40 preferably has a moisture permeability of 1.5 g / (100 cm 2 h), more preferably 1.8 g / (100 cm 2 h), and more preferably 2.0 g / (100 cm 2 The moisture permeability was measured according to the JIS Z-0208 cup method (condition B: 40±0.5°C, humidity 90±2%).

[0021] In order to prevent leakage when the diaper 1 is worn, the backsheet 40 preferably has a water pressure resistance of 800 mmAq or more, more preferably 1000 mmAq or more, and even more preferably 1200 mmAq or more.

[0022] The water resistance is measured in accordance with the JIS L1092-1998 Water Resistance Test (Hydrostatic Pressure Method) Method A (Low Water Pressure Method). In detail, when performing the water resistance test, a nylon mesh sheet (pore size: 133 μm, thickness: 121 μm, Kurabo Industries, Ltd., DO-ML-20) is placed on top of the test piece (back sheet 40) to perform the measurement. If the size of the test piece does not meet the regulations, a device with a reduced measurement area is assembled so that water hits the test piece of the area that can be collected, and the water resistance can be measured in the same manner. Three test pieces are prepared for the back sheet 40 to be measured, and measurements are performed on each of them, and the arithmetic average value of the measured values ​​is taken as the water resistance of the back sheet 40.

[0023] As shown in Figs. 1 and 2, the diaper 1 further includes a top sheet 30 disposed on the skin-facing side of the absorbent body 20. The top sheet 30 covers at least the skin-facing side of the absorbent body 20 and contacts the wearer's skin when worn. The top sheet 30 has a pair of lateral extensions 31, 31 extending outward in the lateral direction Y from each side edge of the absorbent body 20. Each of the lateral extensions 31 is folded back toward the non-skin-facing side of the absorbent body 20 to cover the side surface of the absorbent body 20 and each side region of the non-skin-facing surface. The side edges 31S of the folded back lateral extensions 31 are spaced apart in the lateral direction Y. Therefore, a central region 31D in the lateral direction Y of the non-skin-facing surface of the absorbent body 20 is not covered by the top sheet 30. The lateral extensions 31 form part of a liquid-resistant portion 70 described later. A liquid-permeable sheet can be used as the top sheet 30, and examples thereof include nonwoven fabrics produced by various manufacturing methods, perforated nonwoven fabrics which are nonwoven fabrics having through-holes, uneven nonwoven fabrics in which an uneven shape is imparted to at least one surface of the nonwoven fabric, and perforated films which are resin films having through-holes. The top sheet 30 may have a single-layer structure, or a laminate structure in which one or more types of layers are laminated.

[0024] As shown in Figs. 1 to 3, a pair of leakage preventing cuffs 50, 50 extending in the longitudinal direction X are provided on both sides of the skin-facing surface of the diaper 1. As shown in Figs. The leak-preventing cuff 50 includes a rectangular leak-preventing cuff-forming sheet 51, and a first elastic member 52a and a second elastic member 52b that are stretchable in the longitudinal direction X. The leak-preventing cuff 50 is formed by folding one leak-preventing cuff-forming sheet 51 in half and joining the two opposing leak-preventing cuff-forming sheets 51 together. The first elastic member 52a and the second elastic member 52b are disposed between the two opposing leak-preventing cuff-forming sheets 51. Each of the leakage preventing cuffs 50 has a base end 5A where the leakage preventing cuffs 50 are joined by the back sheet 40 and the absorber 20, and a free end 5B located at a position spaced from the base end 5A. The base end 5A and the free end 5B both extend along the longitudinal direction X and are substantially parallel to each other. The free end 5B is located at the folding line 5F of the leakage preventing cuff-forming sheet 51 folded in half. A first elastic member 52a is disposed along the free end 5B. As a result, when the leakage preventing cuffs 50 are worn with the diaper 1 on, the base end 5A serves as an upright point and the free end 5B side stands up against the wearer's skin.

[0025] Between the base end 5A and the free end 5B of the leakage preventing cuff 50, the second elastic member 52b is disposed along the vertical direction X. This makes it easier for the leakage preventing cuff 50 to bend inward in the horizontal direction Y at the position where the second elastic member 52b is disposed, making it easier to form an inwardly folded leakage preventing cuff 50.

[0026] 2 and 3, the leakage preventing cuff-forming sheet 51 has a first side edge 5a and a second side edge 5b extending along the extension direction of the fold line 5F. As shown in the figures, when the leakage preventing cuff-forming sheet 51 is folded in half along the fold line 5F, the first side edge 5a and the second side edge 5b do not overlap in the thickness direction. The first side edge 5a and the second side edge 5b are located between the absorbent body 20 and the backsheet 40. The first side edge 5a is located inward of the second side edge 5b in the lateral direction Y. The first side edge 5a of one leakage-preventing cuff-forming sheet 51 and the first side edge 5a of the other leakage-preventing cuff-forming sheet 51 are spaced apart in the lateral direction Y. As a result, between the absorbent body 20 and the backsheet 40, there are formed an outer multilayer region 53 in which two leakage-preventing cuff-forming sheets 51 are superposed, and an inner single-layer region 54 located inward of the outer multilayer region 53 in the lateral direction Y and consisting of only one leakage-preventing cuff-forming sheet 51. The outer multilayer region 53 and the inner single-layer region 54 are adjacent to each other, and no gap exists between them. The outer multilayer region 53 forms a part of an outer liquid-resistant region 71 described below, and the inner single-layer region 54 forms a part of an inner liquid-resistant region 72 described below.

[0027] 2 and 3, the side edge 31S of the lateral extension 31, which is the side edge of the topsheet 30, overlaps in the thickness direction with the first side edge 5a of the leakage preventing cuff-forming sheet 51. Alternatively, the side edge 31S of the lateral extension 31 may be located more inward in the lateral direction Y than the first side edge 5a of the leakage preventing cuff-forming sheet 51, or the first side edge 5a of the leakage preventing cuff-forming sheet 51 may be located more inward in the lateral direction Y than the side edge 31S of the lateral extension 31.

[0028] In addition to the above-mentioned configuration, the diaper 1 of this embodiment has a liquid-resistant portion 70 between the absorber 20 and the backsheet 40 for preventing the transfer of liquid from the absorber 20 to the backsheet 40. The liquid-resistant portion 70 has a function of physically preventing the transfer of liquid from the absorber 20 to the backsheet 40 by the constituent material of the liquid-resistant portion 70. The liquid resistant regions 70 have a pair of outer liquid resistant regions 71 located outward in the lateral direction Y of the diaper 1, and a pair of inner liquid resistant regions 72 located inward in the lateral direction Y of the outer liquid resistant regions 71. The pair of inner liquid resistant regions 72 are spaced apart from each other in the lateral direction Y.

[0029] The outer liquid resistant region 71 is located at the outermost position in the lateral direction Y of the diaper 1. The outer liquid resistant region 71 and the inner liquid resistant region 72 are adjacent to each other, with no gap therebetween.

[0030] The outer liquid-resistant region 71 and the inner liquid-resistant region 72 are both made of sheet material. The outer liquid-resistant region 71 includes a portion 31A of the lateral extension 31 of the topsheet 30 located outward in the lateral direction Y, and the outer multi-layer region 53 of the leakage-preventive cuff-forming sheet 51. The inner liquid-resistant region 72 includes a portion 31B of the lateral extension 31 of the topsheet 30 located inward in the lateral direction Y, and the inner single-layer region 54 of the leakage-preventive cuff-forming sheet 51. As a result, the number of laminated sheets of sheet material constituting the outer liquid-resistant region 71 is greater than the number of laminated sheets of sheet material constituting the inner liquid-resistant region 72.

[0031] Since the outer liquid-resistant region 71 and the inner liquid-resistant region 72 are made of different numbers of sheet materials, the outer liquid-resistant region 71 has a higher basis weight than the inner liquid-resistant region 72. When the diaper 1 is worn, a greater external force is more likely to be applied to the outer multilayer region 53 than to the inner single-layer region 54, so that most of the liquid that seeps out from the absorbent body 20 tends to diffuse outward in the lateral direction Y. In the diaper 1 of this embodiment, the basis weight of the outer liquid-resistant region 71, in which liquid is more likely to diffuse, is higher than the basis weight of the inner liquid-resistant region 72, so that leakage of liquid from the backsheet 40 can be more effectively suppressed.

[0032] From the viewpoint of more effectively suppressing leakage of liquid from the backsheet 40, the ratio of the basis weight of the outer-side liquid-resistant region 71 to the basis weight of the inner-side liquid-resistant region 72 is preferably 1.1 or more, more preferably 1.2 or more, and even more preferably 1.3 or more. In addition, the ratio of the basis weight of the outer-side liquid-resistant region 71 to the basis weight of the inner-side liquid-resistant region 72 is preferably 3.0 or less, more preferably 2.8 or less, and even more preferably 2.5 or less. From the same viewpoint, the basis weight of the outer liquid-resistant portion 71 itself is preferably 18 g / m 2More preferably, 19 g / m 2 More preferably, 20 g / m 2 The basis weight of the outer liquid-resistant portion 71 itself is preferably 60 g / m 2 Less than 55g / m 2 More preferably, 50 g / m 2 The following is the result. From the same viewpoint, the basis weight of the inner liquid-resistant portion 72 itself is preferably 8 g / m2, provided that the basis weight is lower than the basis weight of the outer liquid-resistant portion 71. 2 Less than 9g / m 2 More preferably, 10 g / m 2 The basis weight of the inner liquid resistant portion 72 itself is preferably 45 g / m or less, provided that the basis weight is lower than the basis weight of the outer liquid resistant portion 71. 2 Less than 42 g / m, more preferably 2 More preferably 39 g / m or less 2 The following is the result.

[0033] In this embodiment, the basis weight of the outer liquid-resistant region 71 is the sum of the basis weight of the topsheet 30 and twice the basis weight of the leakage-proof cuff-forming sheet 51. On the other hand, the basis weight of the inner liquid-resistant region 72 is the sum of the basis weight of the topsheet 30 and the basis weight of the leakage-proof cuff-forming sheet 51.

[0034] An adhesive is applied to the skin-facing surface of the backsheet 40 only in the area that is in direct contact with the liquid-resistant region 70, thereby bonding the backsheet 40 to the liquid-resistant region 70. In detail, as shown in Fig. 3, in the outer liquid-resistant region 71 of the liquid-resistant region 70, the outer multilayer region 53 and the backsheet 40 are bonded to each other by an adhesive 71A. In the inner liquid-resistant region 72, the inner single-layer region 54 and the backsheet 40 are bonded to each other by an adhesive 72A. For convenience of explanation, the adhesives 71A and 72A shown in Figs. 2 and 3 are shown to be spaced apart from each other in the lateral direction Y, as if a gap were formed, but in reality, no gap exists between the adhesives 71A and 72A.

[0035] Between the pair of inner liquid-resistant regions 72, a space 80 is formed, which is defined by the skin-facing surface of the backsheet 40 and the non-skin-facing surface of the absorbent body 20. The space 80 has a height corresponding to the thickness of the leakproof cuff-forming sheet 51 located between the backsheet 40 and the absorbent body 20. No liquid-resistant regions 70 are arranged in the space 80, and no adhesives 71A, 72A joining the backsheet 40 and the liquid-resistant regions 70 are arranged either.

[0036] The diaper 1 of the present embodiment having such a configuration has the liquid resistant portion 70 and the space 80, and therefore can suppress the liquid seeping out from the absorbent 20 through the back sheet 40 when the diaper 1 is worn. Specifically, the liquid resistant portion 70 is made of a laminated structure of a plurality of sheet materials, and each of the sheet materials functions as a shielding layer against liquid. As a result, when liquid seeping out from the absorbent 20 transfers to the back sheet 40, the sheet materials constituting the liquid resistant portion 70 prevent the liquid from seeping out further. As a result, the leakage of liquid from the back sheet 40 can be suppressed. The inventors' investigations revealed that the seeping out of liquid is prominent in areas where adhesive is applied, and according to the present embodiment, the seeping out of liquid from such areas is also effectively suppressed.

[0037] In addition, in the space 80, the absorbent 20 and the back sheet 40 are separated, so that liquid migration through the constituent materials of the diaper 1 is unlikely to occur. This prevents the liquid held in the absorbent 20 from seeping out further by the space 80. As a result, leakage of liquid from the back sheet 40 can be suppressed. Since liquid migration through the constituent materials is unlikely to occur in the space 80, leakage of liquid from the back sheet 40 can be more effectively performed than in the liquid-resistant portion 70. In general, in absorbent articles, liquid tends to leak more easily in the central region in the lateral direction Y than in the side regions, so that the space 80 defined in the central region in the lateral direction Y is advantageous in that it more effectively suppresses leakage of liquid from the back sheet 40 when the diaper is worn.

[0038] From the above viewpoints, the thickness of the leakage-barrier cuff-forming sheet 51 used to define the space 80 is preferably 0.10 mm or more, more preferably 0.12 mm or more, and even more preferably 0.15 mm or more.

[0039] The thickness of the sheet 51 for forming the leak-proof cuffs is measured by the following method. 2 (0.5gf / cm 2 The thickness is measured at five or more points using a laser displacement meter while a load of 100 mm is applied. The arithmetic mean value of the thickness is defined as the thickness (mm) of the leak-proof cuff-forming sheet 51.

[0040] It is preferable to use adhesive 71A that bonds the outer multilayer region 53 and the back sheet 40, and adhesive 72A that bonds the inner single layer region 54 and the back sheet 40, which have flexibility sufficient to follow the movement of the leakproof cuffs 50 when the diaper 1 is worn.

[0041] In particular, from the viewpoint of facilitating the manufacture of the diaper 1, it is preferable that both the adhesive 71A and the adhesive 72A are hot melt adhesives. As the hot melt adhesive, various known adhesives can be used. For example, various adhesives containing a tackifier such as a petroleum resin or a polyterpene resin, a plasticizer such as a paraffin-based oil, and, if necessary, an antioxidant such as a phenol-based, amine-based, phosphorus-based, or benzimidazole-based antioxidant can be used. Examples of various adhesives include acrylic adhesives containing one or more vinyl monomer (co)polymers (such as ethylene-vinyl acetate copolymers) including 2-ethylhexyl acrylate, butyl acrylate, ethyl acrylate, cyanoacrylate, vinyl acetate, methyl methacrylate, etc., silicone adhesives containing polydimethylsiloxane polymers, etc., as well as natural rubber adhesives containing natural rubber, isoprene adhesives containing one or more polyisoprene, chloroprene, etc., rubber adhesives such as styrene-butadiene copolymers (SBR), styrene-isoprene-styrene block copolymers (SIS), styrene-butadiene-styrene block copolymers (SBS), styrene-ethylene-butadiene-styrene block copolymers (SEBS), and styrene-ethylene-propylene-styrene block copolymers (SEPS). These may be used alone or in combination of two or more.

[0042] When the diaper 1 is worn, the regions disposed around the legs of the wearer are more likely to be subjected to external forces resulting from the wearer's movements. In other words, when the diaper 1 is worn, the outer multilayer region 53 is more likely to be subjected to external forces greater than those of the inner single-layer region 54. Therefore, from the viewpoint of maintaining the shape of the diaper 1 when worn, it is preferable that the basis weight of the adhesive 71A bonding the outer liquid-resistant region 71 in the outer multilayer region 53 to the backsheet 40 is greater than the basis weight of the adhesive 72A bonding the inner liquid-resistant region 72 in the inner single-layer region 54 to the backsheet 40.

[0043] In order to maintain the shape of the diaper 1 when worn, the ratio of the basis weight of adhesive 71A to the basis weight of adhesive 72A is preferably 1.1 or more, more preferably 1.2 or more, and even more preferably 1.3 or more. The ratio of the basis weight of adhesive 71A to the basis weight of adhesive 72A is preferably 4 or less, more preferably 3.5 or less, and even more preferably 3 or less. From the same viewpoint, the basis weight of the adhesive 71A itself is preferably 2 g / m 2 More preferably, 3 g / m 2 More preferably, 4 g / m 2 The basis weight of the adhesive 71A itself is preferably 10 g / m 2 Less than 9g / m 2 More preferably, 8 g / m or less 2 The following is the result. From the same viewpoint, the basis weight of the adhesive 72A itself is preferably 1 g / m, provided that the basis weight is lower than the basis weight of the adhesive 71A. 2 More preferably, 1.5 g / m 2 More preferably, 2 g / m 2 The basis weight of the adhesive 72A itself is preferably 9 g / m, provided that it is lower than the basis weight of the adhesive 71A. 2 Less than or equal to 8 g / m 2 More preferably, 7 g / m or less 2 The following is the result.

[0044] It is preferable to use a fiber sheet having air permeability and high resistance to liquid permeation as at least a part of the sheet material constituting the outer side liquid-resistant portion 71 and the sheet material constituting the inner side liquid-resistant portion 72. An example of such a fiber sheet is a nonwoven fabric having a meltblown nonwoven fabric. Specifically, a meltblown nonwoven fabric can be used as the sheet material constituting at least a part of the outer side liquid-resistant portion 71 and the sheet material constituting at least a part of the inner side liquid-resistant portion 72. Alternatively, a laminated nonwoven fabric in which a spunbond nonwoven fabric is disposed on at least one surface of a meltblown nonwoven fabric, such as a spunbond-meltblown (SM) composite nonwoven fabric, a spunbond-meltblown-spunbond (SMS) composite nonwoven fabric, or a spunbond-meltblown-meltblown-spunbond (SMMS) composite nonwoven fabric can be used.

[0045] As shown in Figures 2 and 3, an indicator 90 that notifies urination by a change in color is provided in the region of the skin-facing surface of the backsheet 40 facing the space 80. The indicator 90 is preferably arranged at least in the crotch portion M. In the embodiment shown in Figure 2, a plurality of indicators 90 are arranged to extend in the vertical direction X from the crotch portion M to the ventral portion F and the dorsal portion R. Although the indicators 90 shown in Figure 2 are shown to have the same basis weight, this is merely for convenience of explanation, and they may be formed to have the same basis weight as shown in the figure, or alternatively, they may be formed to have different basis weights.

[0046] In this specification, "color change" includes not only a change from one color to another, but also so-called "coloring" from a colorless state to a colored state and so-called "discoloration" from a colored state to a colorless state. The change in color of the indicator 90 can be visually observed by the wearer, or the caregiver or caregiver of the wearer, to serve as an indication of when to change the diaper 1.

[0047] The indicator 90 may contain a coloring material that changes color when it comes into contact with excrement containing moisture such as urine or sweat, and may be any of the indicators that have been used in this type of absorbent article. The coloring material constituting the indicator may be, for example, a mixture of a pH indicator and an oxidizing compound. The indicator 90 is formed by kneading the coloring material constituting the indicator into a hot melt adhesive, and applying the hot melt adhesive to the skin-facing surface of the back sheet 40.

[0048] The indicator 90 made of hot melt adhesive containing a coloring material exhibits resistance to liquid penetration due to the hydrophobicity of the hot melt adhesive. Therefore, the use of such an indicator 90, together with the formation of the space 80, effectively prevents the liquid held in the absorbent body 20 from migrating to the back sheet 40. Furthermore, by providing the indicator 90 in a region of the skin-facing surface of the backsheet 40 facing the space 80, the indicator 90 faces the central region in the lateral direction Y of the absorbent body 20 where the amount of liquid held is greatest. This increases the chance that the indicator 90 will come into contact with liquid, making it easier to accurately determine when to change the diaper 1.

[0049] 2 to 4, the absorbent core 21 has a two-layer structure including an upper absorbent core 21A and a lower absorbent core 21a located on the non-skin facing side of the upper absorbent core 21A. The non-skin facing side of the upper absorbent core 21A abuts against the skin facing side of the lower absorbent core 21a. The upper absorbent core 21A and the lower absorbent core 21a are covered with a core wrap sheet 22.

[0050] In a plan view, the upper absorbent core 21A has an elongated shape with the front side in the vertical direction X (the portion closer to the ventral side portion F) being wider than other portions, and has a shorter length in the vertical direction X than the lower absorbent core 21a, and a shorter length in the horizontal direction Y than the length (width) of the lower absorbent core 21a. The lower absorbent core 21a has a generally rectangular shape that is long in the vertical direction X in plan view, and has a larger dimension (area) in plan view than the upper absorbent core 21A. In a plan view, the upper absorbent core 21A entirely overlaps with the lower absorbent core 21a, and the lower absorbent core 21a extends outward from the periphery of the upper absorbent core 21A. As a result, the lower absorbent core 21a forms the outline of the absorbent core 21. The upper absorbent core 21A is located on the skin-facing surface of the lower absorbent core 21a at a position slightly biased toward the ventral side from the center in the longitudinal direction X of the lower absorbent core 21a. The upper absorbent core 21A and the lower absorbent core 21a may be joined to each other by an adhesive, but in this embodiment, the two are not joined to each other, and are separable rather than being integral and inseparable.

[0051] A narrow lower layer central opening 21b is formed in the central region of the lower layer absorbent core 21a in the lateral direction Y so as to extend in the longitudinal direction X and penetrate the lower layer absorbent core 21a in the thickness direction. At the same time, a pair of narrow lower layer side openings 21c, 21c are formed on both sides of the lower layer central opening 21b in the lateral direction Y so as to extend in the longitudinal direction X and penetrate the lower layer absorbent core 21a in the thickness direction, and are symmetrical with respect to the lower layer central opening 21b (the longitudinal center line CLx extending in the longitudinal direction X so as to divide the diaper 1 in half in the longitudinal direction X). The pair of lower layer side openings 21c, 21c have the same length, and the positions of both ends thereof are aligned with each other. These openings 21b, 21c are both spaces where no absorbent core-forming material exists, and are disposed at least in the crotch portion M. These openings 21b, 21c are both narrow, that is, the length (width) in the horizontal direction Y is shorter than the length in the vertical direction X.

[0052] An end 21d on the ventral portion F side of the lower central opening 21b is located closer to the ventral portion F than an end 21e on the ventral portion F side of the pair of lower layer lateral openings 21c. On the other hand, an end 21f on the dorsal portion R side of the lower central opening 21b is located closer to the ventral portion F than an end 21g on the dorsal portion R side of the pair of lower layer lateral openings 21c.

[0053] On the other hand, in the upper absorbent core 21A, an upper central opening 21B is formed in a region overlapping with the lower central opening 21b of the lower absorbent core 21a in a plan view, penetrating the upper absorbent core 21A in the thickness direction and extending in the vertical direction X. The length of the upper central opening 21B is the same as the length of the lower central opening 21b. In addition, the positions of both ends of the upper central opening 21B are the same as the positions of both ends of the lower central opening 21b. Therefore, when the upper absorbent core 21A and the lower absorbent core 21a are stacked, a narrow central opening 23A is formed penetrating the absorbent core 21 in the thickness direction. The central opening 23A is located in the central region in the horizontal direction Y of the absorbent core 21 and extends along the vertical direction X.

[0054] The central opening 23A is a portion where the constituent material of the absorbent core 21 is partially missing. In other words, the central opening 23A is a non-stacking portion where there is no constituent material of the absorbent core 21 at all or where there is a small amount of constituent material. Therefore, in the following description, the central opening 23A is also referred to as the central non-stacking portion 23. By forming the central non-stacking portion 23 in the absorbent core 21, the core wrap sheet 22 covering the absorbent core 21 can bend toward the inside of the absorbent core 21 at the position of the central non-stacking portion 23.

[0055] When the upper absorbent core 21A and the lower absorbent core 21a are stacked, the lower side openings 21c, 21c formed in the lower absorbent core 21a are located on the sides of the upper absorbent core 21A, as shown in Fig. 4. Therefore, when the upper absorbent core 21A and the lower absorbent core 21a are stacked, a narrow side opening 24A is formed that penetrates the absorbent core 21 in its thickness direction. The side openings 24A extend in the vertical direction X and are formed symmetrically with respect to the central opening 23A.

[0056] The side opening 24A is a portion where the constituent material of the absorbent core 21 is partially missing. In other words, the side opening 24A is a non-stacking portion where there is no constituent material of the absorbent core 21 at all or where there is a small amount of constituent material. Therefore, in the following description, the side opening 24A is also referred to as a side non-stacking portion 24. By forming the side non-stacking portions 24 in the absorbent core 21, the core wrap sheet 22 covering the absorbent core 21 can bend toward the inside of the absorbent core 21 at the positions of the side non-stacking portions 24.

[0057] Since the absorbent body 20 has the central non-stacking portion 23 and the side non-stacking portions 24, the core wrap sheet 22 present at the positions corresponding to the non-stacking portions 23, 24 tends to bend inwardly of the absorbent body 20. As a result, the space 80 defined by the back sheet 40 and the absorbent body 20 tends to become larger. This makes it more difficult for liquid to migrate from the absorbent body 20 to the back sheet 40 via the constituent materials of the diaper 1. As a result, leakage of liquid from the back sheet 40 can be more effectively suppressed.

[0058] 2 and 3, the area where adhesive 72A is applied, which bonds the inner liquid-resistant portion 72 and the backsheet 40, overlaps in the thickness direction with the side non-stacking portion 24, which is one of the non-stacking portions in the absorbent core 21. As described above, in the moisture-permeable backsheet 40, liquid leakage is likely to occur in the area where adhesive is applied, but according to the embodiment shown in Fig. 2 and 3, the area of ​​the absorbent core 21 facing the area where adhesive 72A is applied is a non-stacking portion, which has the advantage that seepage of liquid from the absorbent body 20 to the backsheet 40 is even less likely to occur.

[0059] While the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above-described embodiments and can be modified as appropriate without departing from the spirit of the present invention. For example, the adhesive 71A and the adhesive 72A shown in FIG. 2 may be applied separately to the backsheet 40 so that a gap is formed between the adhesives 71A and 72A.

[0060] In addition, in the embodiment shown in Figure 2, the outer side liquid-resistant portion 71 is made up of three sheets of sheet material and the inner side liquid-resistant portion 72 is made up of two sheets of sheet material, but there is no limit to the number of layers of the outer side liquid-resistant portion 71 and the inner side liquid-resistant portion 72, provided that the number of layers of the sheet material constituting the outer side liquid-resistant portion 71 is greater than the number of layers of the sheet material constituting the inner side liquid-resistant portion 72.

[0061] 2, the position of the side edge 31S of the lateral extension 31 of the topsheet 30 coincides with the position of the first side edge 5a of the leakage preventing cuff 50, but instead the position of the side edge 31S may be outward in the lateral direction Y from the position of the first side edge 5a of the leakage preventing cuff 50. Alternatively, as long as a sufficient space 80 is secured, the position of the side edge 31S may be inward in the lateral direction Y from the position of the first side edge 5a of the leakage preventing cuff 50.

[0062] In the above embodiment, the present invention is applied to a pants-type disposable diaper, but the application of the present invention is not limited to this, and the present invention may be applied to disposable diapers of types other than pants-type disposable diapers, and absorbent articles other than disposable diapers, such as sanitary napkins, incontinence pads, and panty liners. [Explanation of symbols]

[0063] 1. Pants-type disposable diapers 20 Absorber 21 Absorbent Core 22 Core wrap sheet 30 Surface sheet 40 Back sheet 50 Leak proof cuff 53 Outer multilayer area 54 Inner single layer area 60 Exterior body 70 Fluid-resistant areas 71 Lateral fluid resistant area 72 Medial fluid resistant area 80 space F ventral part M Inseam R dorsal part X vertical direction Y Horizontal

Claims

1. An absorbent article comprising an absorbent body and a moisture-permeable backsheet disposed on the non-skin-facing side of the absorbent body, a liquid-resistant portion is provided between the absorbent body and the back sheet to prevent liquid from migrating from the absorbent body to the back sheet; the liquid-resistant regions include a pair of outer-side liquid-resistant regions located on the outer sides in the lateral direction of the absorbent article, and a pair of inner-side liquid-resistant regions located inward in the lateral direction of the outer-side liquid-resistant regions, The pair of inner fluid-resistant portions are spaced apart from each other in the lateral direction, the outer liquid-resistant portion has a basis weight higher than that of the inner liquid-resistant portion, an adhesive is applied to the skin-facing surface of the backsheet only in an area that is in direct contact with the liquid-resistant portion, thereby joining the backsheet and the liquid-resistant portion; An absorbent article wherein a space defined by the backsheet and the absorbent body is formed between the pair of inner liquid-resistant regions.

2. Further provided is a top sheet disposed on the skin-facing side of the absorbent body, the topsheet has lateral extensions extending outward in the lateral direction from each side edge of the absorbent body, The absorbent article according to claim 1 , wherein the lateral extensions are folded back toward the non-skin-facing surface of the absorbent body to form part of the liquid-resistant region.

3. 3. An absorbent article as described in claim 1 or 2, wherein the basis weight of the adhesive joining the outer side liquid-resistant region and the back sheet is higher than the basis weight of the adhesive joining the inner side liquid-resistant region and the back sheet.

4. the outer liquid-resistant portion and the inner liquid-resistant portion are both made of a sheet material; The absorbent article according to claim 1 or 2, wherein the number of sheets forming the outer liquid-resistant portion is greater than the number of sheets forming the inner liquid-resistant portion.

5. 5. The absorbent article according to claim 4, wherein at least a portion of the sheet material constituting the outer liquid-resistant region and the sheet material constituting the inner liquid-resistant region is made of a spunbond-meltblown-spunbond composite nonwoven fabric.

6. The absorbent body has an absorbent core containing water-absorbent fibers and a core wrap sheet covering the absorbent core, The absorbent article according to claim 1 or 2, wherein the absorbent core has, in a central region in the lateral direction, a non-stacking portion in which a constituent material of the absorbent core is partially missing.

7. The absorbent article according to claim 6, wherein the adhesive-coated area that bonds the inner liquid-resistant portion and the backsheet and the non-stacking portion overlap in the thickness direction.

8. The absorbent article according to claim 6, wherein the portion of the core wrap sheet located on the non-skin-facing surface of the absorbent core is made of a spunbond-meltblown-spunbond composite nonwoven fabric.

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