AU2008264565A1 - Absorbent article - Google Patents

Description

1 DESCRIPTION ABSORBENT ARTICLE 5 Technical Field [0001] The present invention relates to absorbent articles that absorb liquid. Background Art 10 [0002] In absorbent articles such as diapers or sanitary napkins, when moisture is kept between the user's skin and an absorbent article, the user feels discomfort due a stuffy sensation. [0003] Therefore, an absorbent article has been proposed in which a surface sheet that contacts skin is formed in an irregular shape so as to secure 15 a gap that can serve as a flow path for air (moisture) (see, for example, Japanese Patent Publication No. 3587831). Disclosure of Invention Problem to be Solved by the Invention 20 [0004] However, the irregular shape of the surface sheet disclosed in Japanese Patent Publication No. 3587831 is formed by subjecting part of a fiber aggregate (fibrous web) to heat adhesion by heat-embossing or the like. For this reason, density is higher in the concave section where fibers were heat-adhered than in the convex section. 25 In such an absorbent article, moisture (liquid) cannot smoothly pass through inside the concave section, andmoisture is kept between the user's skin and the absorbent article, which causes a stuffy sensation. Therefore, it is an advantage of the invention to provide an absorbent article which is unlikely to cause a stuffy sensation. 30 Means for Solving the Problem [0005] According to a primary aspect of the invention is an absorbent article including: a liquid-permeable surface sheet; a liquid-impermeable back face sheet; and a liquid-retaining absorbent body 35 disposed between the surface sheet and the back face sheet, the surface 2 sheet including a concave section and a convex section so that the surface thereof has an irregular shape, the concave section having a lower weight per unit area than the convex section, the absorbent body including an interspersed section where a superabsorbent resin is densely gathered. 5 [0006] Features and advantages of the invention other than the above will become clear by reading the description of the present specification with reference to the accompanying drawings. Effects of the Invention 10 [0007] According to the invention, it is possible to provide an absorbent article which is unlikely to cause a stuffy sensation. Brief Description of Drawings [0008] [FIG. 1] FIG. 1A is a top view of a sanitary napkin, and FIG. 1B 15 is a cross-sectional view of the sanitary napkin. [FIG. 2] FIG. 2A is a top view of a nonwoven fabric, and FIG. 2B is an enlarged perspective view of the nonwoven fabric. [FIG. 3A] This is a diagram showing how a fluid is sprayed against a fibrous web. 20 [FIG. 3B] This is a diagram showing a production apparatus of the nonwoven fabric. [FIG. 4] FIG. 4A is a perspective view of a second sheet, and FIG. 4B is a cross-sectional view of the second sheet. [FIG. 5] FIGS. 5A to 5D show a method for producing the nonwoven fabric. 25 [FIG. 6] FIG. 6A shows a top view of the absorbent body, and FIG. 6B is a cross-sectional view of an interspersed section. [FIG. 7] FIGS. 7A to 7D show how liquid that has been excreted onto a sanitary napkin is absorbed. [FIG. 8] This is a table describing constituent fibers of nonwoven 30 fabrics used for evaluation. [FIG. 9] This shows the structure of evaluated objects and results of measuring a rewet rate. [FIG. 10] FIG. 1OA shows a surface sheet of a third embodiment, and FIG. 10B shows a surface sheet of a fourth embodiment. 35 3 List of Reference Numerals (0009] 1 sanitary napkin (absorbent article), 2 surface sheet, 3 second sheet, 3' nonwoven fabric, 4 absorbent body, 5 back face sheet, 6 convex 5 section, 61 central section, 62 lateral section, 7 concave section, 8 side sheet, 9 wing section, 10 nonwoven fabric, 11 fibrous web (fiber aggregate), 12 breathable support member, 13 conveyor, 10 131 belt section, 14 spraying device, 15 spraying section, 16 spraying opening, 17 air intake section, 18 heating section, 31 high density region, 32 low density region, 33 breathable net, 34 fibrous web, 35 convex section, 15 36 concave section, 41 bulging section, 43 absorbent body material, 44 absorbent fiber (pulp fiber), 45 superabsorbent resin (SAP), 46 embossing, 47 deep channel section, 48 interspersed section, 50 liquid 51 surface sheet of the third embodiment, 52 surface sheet of the fourth 20 embodiment, 53 opening section Best Mode for Carrying Out the Invention [0010] At least the following matters will be made clear by reading the 25 description of the present specification with reference to the accompanying drawings. [0011] An absorbent article including: a liquid-permeable surface sheet; a liquid-impermeable back face sheet; and a liquid-retaining absorbent body disposed between the surface sheet and the back face sheet, the 30 surface sheet including a concave section and a convex section so that the surface thereof has an irregular shape, the concave section having a lower weight per unit area than the convex section, the absorbent body including an interspersed section where a superabsorbent resin is densely gathered. 35 [0012] In such an absorbent article, the distance between the user's skin 4 and the absorbent body is reduced due to the concave section of the surface sheet, and also the concave section has a low weight. Therefore, absorption of moisture (liquid) by the absorbent body is facilitated. In addition, moisture that has passed through the concave section can 5 be further absorbed due to the superabsorbent resin. That is, the above-described absorbent article is unlikely to cause a stuffy sensation. Also, regions where the superabsorbent resin particles join together when the superabsorbent resin has absorbed liquid are interspersed, and therefore a phenomenon in which absorption of excreted liquid is 10 interfered with (a blocking phenomenon) can be prevented. Specifically, a stuffy sensation is unlikely to occur since the surface sheet can be maintained in a dry condition. Also, the user's skin and the absorbent body are distanced from each other due to the convex section of the surface sheet, and liquid can be prevented from returning to the surface sheet. 15 [0013] In such an absorbent article, the absorbent body includes an absorbent fiber, and a fiber density of the absorbent fiber in the interspersed section is lower than a fiber density of the absorbent fiber in the absorbent body other than the interspersed section. In such an absorbent article, the absorbent body can be prevented from 20 bulging in the thickness direction in the case where the superabsorbent resin has retained a large amount of moisture and swelled. [0014] In such an absorbent article, a content rate of the interspersed section is higher in an end section in a longitudinal direction of the absorbent body than in a central section in the longitudinal direction 25 of the absorbent body. In such an absorbent article, the interspersed sections located at the end sections can play a role of absorbing moisture until liquid excreted in the central section moves to the end section sides, and therefore moisture that has passed through the concave section can be 30 further absorbed. [0015] Such an absorbent article includes a liquid-permeable second sheet made up of a nonwoven fabric disposed between the absorbent body and the surface sheet, wherein the second sheet includes a high density region having a fiber density higher than an average fiber density of the nonwoven 35 fabric forming the second sheet, and a low density region having a fiber 5 density lower than the average fiber density, the high density region and the low density region penetrating from the surface sheet side to the absorbent body side in the thickness direction of the nonwoven fabric. In such an absorbent article, a large amount of liquid or liquid having 5 a high viscosity can be passed through quickly due to the low density region, and due to the high density region, a small amount of liquid or liquid remaining inside the surface sheet can be drawn due to the capillary force and forwarded to the absorbent body. Also, while returning of liquid can be prevented by the thickness of the second sheet, since the concave 10 section is provided in the surface sheet, the user's skin is prevented from being distanced from the absorbent body too much. As a result, a stuffy sensation is unlikely to occur. [0016] In such an absorbent article, the surface sheet is a nonwoven fabric formed by a fiber aggregate whose surface has an irregular shape as a 15 result of having been sprayed with a fluid. In such an absorbent article, it is possible to make the surface of the surface sheet in an irregular shape, and make the weight in the concave section lower than the weight in the convex section. 20 Outline of Absorbent Article of the Present Embodiment [0017] A description will be given below using a sanitary napkin as an example of the absorbent article. FIG. 1A is a top view of a sanitary napkin 1, and FIG. 1B is a cross-sectional view of the sanitary napkin 1. The sanitary napkin 1 (absorbent article) of the present embodiment 25 includes a liquid-permeable surface sheet 2, a liquid-impermeable back face sheet 5, a liquid-retaining absorbent body 4 disposed between the surface sheet 2 and the back face sheet 5, a second sheet 3 disposed between the surface sheet 2 and the absorbent body 4, and side sheets 8 disposed at both end sides in the width direction. Furthermore, the surface sheet 30 2 includes a concave section 7 and a convex section 6 so that the surface of the surface sheet 2 has an irregular shape. The weight of the concave section 7 is lower than that of the convex section 6. Also, the absorbent body 4 has interspersed sections 48 where a superabsorbent resin 45 (SAP) is densely gathered. Note that in FIG. 1A, the interspersed sections 48 35 provided in the absorbent body 4 are virtually shown with dotted lines.

6 In addition to sanitary napkins, the absorbent article of the present embodiment having such a configuration can be applied to liners, diapers or the like. [0018] The sanitary napkin 1 as a whole has a shape elongated in a 5 predetermined direction, and this predetermined direction is referred to as a longitudinal direction and a direction that intersects the longitudinal direction is referred to as a width direction. The sanitary napkin 1 is worn so that the portion spanning from the front end section to the rear end section in the longitudinal direction of the sanitary 10 napkin 1 contacts a portion spanning from the abdomen to the buttocks of the user. The side of the sanitary napkin 1 that contacts the body is referred to as a surface side, the side that contacts the undergarment is referred to as a back face side, and the normal line direction with respect to the surface or the back face of the sanitary napkin 1 is referred 15 to as a thickness direction. [0019] Next, respective constituent elements of the sanitary napkin 1 will be described in detail. Surface Sheet 2 20 [0020] FIG. 2A is a top view (surface) of a nonwoven fabric 10, and FIG. 2B is an enlarged perspective view of the nonwoven fabric 10. In the sanitary napkin 1 of the present embodiment, the nonwoven fabric 10 whose surface has an irregular shape as a result of having been sprayed with a fluid f, is used as the surface sheet 2. The nonwoven fabric 10 will 25 be described in detail below. [0021] First, the shape of the nonwoven fabric 10 will be described. On the surface side of the nonwoven fabric 10, the convex sections 6 along a direction corresponding to the longitudinal direction of the sanitary napkin 1 (hereinafter referred to as a "longitudinal direction") are 30 formed at equal intervals in a direction corresponding to the width direction of the sanitary napkin 1 (hereinafter referred to as a "width direction"), and the concave sections 7 (channel sections) are formed between the convex sections 6. That is, the convex sections 6 and the concave sections 7 are formed lined up in the width direction on the surface 35 side of the nonwoven fabric 10. On the other hand, the back face side 7 is a substantially flat face. [0022] The height of the convex section 6 in the thickness direction is set to equal to or more than 0.3 mm and equal to or less than 15 mm (preferably, equal to or more than 0.5 mm and equal to or less than 5 5 mm), and the length of the convex section 6 in the width direction is set to equal to or more than 0.5 mm and equal to or less than 30 mm (preferably, equal to or more than 1 mm and equal to or less than 10 mm) . Also, the distance between peaks (central section in the width direction) of the convex sections 6 that are adjacent to each other with the concave 10 section 7 placed therebetween is set to equal to or more than 0.5 mm and equal to or less than 30 mm (preferably, equal to or more than 3 mm and equal to or less than 10 mm). [00231 The height of the concave section 7 in the thickness direction is set to a height equal to 90% of the height of convex section 6 or lower 15 (preferably, a height in a range between equal to or more than 1% and equal to or less than 50% relative to the convex section 6) . The length of the concave section 7 in the width direction is set to equal to or more than 0.1 mm and equal to or less than 30 mm (preferably, equal to or more than 0.5 mm and equal to or less than 10 mm), and the distance 20 between the central sections of the concave sections 7 that are adjacent to each other with the convex section 6 placed therebetween is set to equal to or more than 0.5 mm and equal to or less than 20 mm (preferably, equal to or more than 3 mm and equal to or less than 10 mm). [0024] Next, a method for producing the nonwoven fabric 10 will be 25 described. [0025] FIG. 3A shows how a fibrous web 11 is sprayed with a fluid f, and FIG. 3B shows a production apparatus of the nonwoven fabric 10. [0026] The nonwoven fabric 10 is produced by spraying the fibrous web 11 (this corresponds to a fiber aggregate; fibers in a state of having a 30 certain degree of freedom between fibers) having a substantially uniform thickness with a fluid f along a predetermined direction (an MD direction, longitudinal direction) from the top face side (the side opposite to a support member) of the fibrous web 11, as shown in FIG. 3A, in a state in which the fibrous web 11 is placed on a breathable support member 12. 35 The fluid f sprayed onto the fibrous web 11 is a fluid mainly constituted 8 by a gas (airflow). [0027] The fibrous web 11 includes a thermoplastic resin fiber, and examples of this thermoplastic resin fiber include single fibers made up of polyethylene (hereinafter referred to as "PE"), polypropylene 5 (hereinafter referred to as "PP"), polyethylene terephthalate or the like, fibers obtained by polymerizing PP and PE, composite fibers of the sheath-core structure composed of PP and PE, or the like. The fibrous web 11 may contain fibers other than the thermoplastic resin fiber, for example, natural fibers such as cellulose. In order to improve whitening 10 properties, for example, inorganic fillers of, for example, titaniumoxide, barium sulfate, calcium carbonate or the like may be contained. In addition, a hydrophilic agent may be kneaded into fibers if improving seeping properties of liquid is desired, and a water-repellent agent may be kneaded into fibers if further prevention of return of liquid is 15 desired. [0028] Specifically, the nonwoven fabric 10 is produced by a nonwoven fabric production apparatus such as the one shown in FIG. 3B. The nonwoven fabric production apparatus causes the fibrous web 11 to be transported with a conveyor 13 in a state supported at the bottom thereof in the MD 20 direction, which is the transport direction. Note that a belt section 131 of the conveyor 13 serves as the breathable support member 12 shown in FIG. 3A. The breathable support member 12 is a support member whose surface is a flat face and having a mesh structure, and is formed by weaving a plurality of wires having a predetermined thickness. This wire portion 25 serves as a non-breathable section where the fluid f cannot flow downward, while the space between the wires serves as a breathable section (opening section) where the fluid f can flow downward. [0029] In this manner, the fibrous web 11 is transported in a state supported at the bottom thereof by the belt section 131, which is the 30 breathable support member 12, in the MD direction, and first, passes under a spraying device 14. The spraying device 14 is constituted by a spraying section 15, spraying openings 16, and an air intake section 17. Fluid f supplied to the spraying section 15 is sprayed toward the fibrous web 11 from the nozzle-shaped spraying openings 16. 35 [0030] The spraying openings 16 are lined up in a row at equal intervals 9 along a CD direction that intersects the MD direction. Since the fibrous web 11 is transported under the spraying openings 16 along the MD direction, the fibrous web 11 is sprayed with the fluid f along the MD direction. Accordingly, fibers in a region sprayed with the fluid f are shifted in 5 the CD direction, and the shifted fibers are blown off to a region that is not sprayed with the fluid f, namely, a region between the regions sprayed with the fluid f. In this manner, the convex section 6 and the concave section 7 are formed along the MD direction on the surface of the fibrous web 11. That is, the region sprayed with the fluid f becomes 10 the concave section 7, and as a result of fibers in the region becoming the concave section 7 being shifted, the region that is not sprayed with the fluid f becomes the convex section 6. Therefore, the weight of the convex section 6 (fiber weight per unit area) is greater than the weight of the concave section 7. 15 [0031] At this time, the fibrous web 11 is in a state supported at the bottom thereof by the breathable support member 12, and therefore fibers in the region sprayed with the fluid f are shifted along the surface of the breathable support member 12. For this reason, the breathable support member 12 side (the back face side) of the fibrous web 11 is in a 20 substantially flat surface shape. Also, since the fluid f sprayed onto the fibrous web 11 flows downward in the breathable support member 12, it is possible to prevent the flow of the fluid f from being changed greatly. Consequently, a good irregular shape can be formed in the fibrous web 11. Supposing that the support member is non-breathable, the fluid f 25 sprayed onto the fibrous web 11 rebounds at the support member, and the irregular shape may not be properly formed. [0032] The fluid f sprayed onto the fibrous web 11 is sucked by the air intake section 17 provided under the belt section 131, and therefore rebound or the like of the fluid f can be further prevented. In addition, 30 due to this air intake, the fibrous web 11 is pressed against the breathable support member 12 so as to be closely attached thereto, and the irregular shape formed in the fibrous web 11 can be maintained. [0033] Thereafter, the fibrous web 11 with the irregular shape having been formed on the top face side (the surface side) thereof is further 35 transported by the conveyor 13, and passes through a heating section 18.

10 In the heating section 18, the fibrous web 11 undergoes heating processing, thermoplastic fibers in the fibrous web 11 undergo heat adhesion, and the nonwoven fabric 10 whose surface has an irregular shape is produced. [0034] Also, while the temperature of the fluid f sprayed onto the fibrous 5 web 11 may be a room temperature, for example, the temperature may be set to a temperature equal to or higher than the softening point of the fibrous web 11 so as to achieve a good formability of the irregular shape of the nonwoven fabric 10, and preferably, set to a temperature equal to or more than a softening point and in a range from equal to or more 10 than -50 degrees C of a melting point to equal to or less than +50 degrees C of a melting point. At such a temperature, fibers constituting the fibrous web 11 are softened and the repulsion force of the fibers themselves is reduced, and therefore the irregular shape formed as a result of the fluid f being sprayed onto the fibrous web 11 is easily maintained. 15 By further increasing the temperature of the fluid f, fibers start undergoing heat adhesion while the irregular shape is being formed on the surface of the fibrous web 11, and therefore the irregular shape is easily maintained. Also in this case, since fibers undergo heat adhesion due to the fluid f, it is possible to omit heat processing by the heating 20 section 18 shown in FIG. 3B. [0035] In addition, in order to transport the fibrous web 11 to the heating section 18 while maintaining the irregular shape thereof formed by the fluid f in a better manner, it is also possible to suck the fibrous web 11 from below the belt section 131 while the fibrous web 11 is transported 25 from the spraying device 14 to the heating section 18, or to provide the heating section 18 at a position on the immediate downstream side from the spraying device 14. Also, in the case where the fluid f is hot air, the fibrous web 11 may be once cooled with cold air or the like immediately after the irregular shape has been formed, such that the formed irregular 30 shape does not gradually change and deform due to residual heat. [0036] Production is performed such that the average weight of the entire nonwoven fabric 10 produced in this manner is equal to or more than 10 g/m2 more and equal or less than 200 g/m 2 (preferably, equal to or more 22 than 20 g/m2 and equal or less than 100 g/m 2 ). When the average weight 35 of the nonwoven fabric 10 is less than 10 g/m 2 , the nonwoven fabric 10 11 is easily broken, and when the average weight is greater than 200 g/m 2 it becomes difficult for the liquid to move downward (to the absorbent body) . (0037] Incidentally, in the nonwoven fabric 10 of the present embodiment, 5 the irregular shape is formed on the surface of the fibrous web 11 by spraying the fibrous web 11 with the fluid f along the MD direction. Therefore as shown in FIG. 2B, the concave section 7 contains a comparatively large amount of fibers oriented in the CD direction (fibers oriented in a random direction in a range from -450 to +45* relative to 10 the CD direction). On the other hand, both of the end sections in the CD direction of the convex section 6 contain fibers that have been blown off from the region that has become the concave section 7, and therefore both of the end sections contain a comparatively large amount of fibers oriented in the MD direction (fibers oriented in a random direction in 15 a range from -45* to +45* relative to the MD direction). Both end sections in the CD direction of the convex section 6 are referred to as lateral sections 62 and the region between the lateral sections 62 in the convex section is referred to as a central section 61. [0038] The weight of the lateral sections 62 in the convex section 6 is 20 greater than the weight of the central section 61. Specifically, the weight of the central section 61 in the convex section 6 is set to equal to or more than 15 g/m 2 and equal to or less than 250 g/m 2 (preferably, equal to or more than 20 g/m 2 and equal to or less than 120 g/m 2 ) , and the weight in the lateral sections 62 is set to equal to or more than 25 20 g/m 2 and equal to or less than 280 g/m 2 (preferably, equal to or more than 25 g/m 2 and equal to or less than 150 g/m 2 ). Also, the weight of the concave section is set to equal to or more than 3 g/m2 and equal to or less than 150 g/m 2 (preferably, equal to or more than 5 g/m 2 and equal to or less than 80 g/m 2 ). 30 [0039] Further, in the nonwoven fabric 10 (the surface sheet 2) of the present embodiment, the fiber density is adjusted so as to be lower in the concave section 7 than in the convex section 6. Specifically, the fiber density of the concave section 7 is set to equal to or more than 0.002 g/m 3 and equal to or less than 0.18 g/m 3 35 (preferably, equal to or more than 0.005 g/m 3 and equal to or less than 12 0.05 g/m 3 ), and that of the convex section 6 is set to equal to or more than 0.005 g/m 3 and equal to or less than 0.20 g/m 3 (preferably, equal to or more than 0.007 g/m 3 and equal to or less than 0.07 g/m 3 ) . [0040] It should be noted that the irregular shape (size or fiber weight, 5 fiber density of the concave and convex portions) can be adjusted by the air volume or temperature of the fluid f sprayed onto the fibrous web 11 during production of the nonwoven fabric 10, the intake volume by the air intake section, breathability of the breathable support member 12 or the like. For example, the height of the convex section 6 can be 10 increased by increasing the size of the spraying openings 16, and can be decreased by decreasing the size of the spraying openings 16. [0041] In this manner, the sanitary napkin 1 (absorbent article) in which the nonwoven fabric 10 having a surface of an irregular shape, in which the weight in the concave section 7 is lower than that in the convex section 15 6, is used as the surface sheet 2 can make it difficult for a stuffy sensation to occur. [0042] This is because the distance between the moisture, present between the user's skin and the surface sheet, and the absorbent body 4 can be shortened due to the concave sections 7 on the surface of the surface 20 sheet 2, and the concave section 7 of the present embodiment has a lower weight than the convex section and a small resistance due to fibers, and therefore the moisture is easily absorbed by the absorbent body 4. [0043] However, when the entire thickness of the surface sheet 2 is reduced as the concave section 7 and the entire weight thereof is also reduced 25 as the concave section 7, so as to improve moisture absorption, the surface sheet 2 is easily broken and the liquid easily returns to the surface sheet 2. Then, the skin of the user will be soiled and the user will feel discomfort (a wet and sticky sensation will be given). [0044] In response to this, as with the surface sheet 2 of the present 30 embodiment, moisture can be easily absorbed by including both of the concave section 7 and the convex section 6 having a greater weight than the concave section 7, and return of liquid can be prevented by distancing the user's skin from the absorbent body 4 by the convex section 6. Also, the convex section 6 can compensate for easiness of breakage of the concave 35 section 7, thereby making the surface sheet 2 strong. Furthermore, since 13 the thickness of the surface sheet 2 is increased by the convex section 6, cushioning properties are enhanced and the wear comfort for the user can be improved. [0045] Even if a nonwoven fabric includes concave sections and convex 5 sections, for example, in the case of a nonwoven fabric whose surface is formed in an irregular shape by heat-embossing a part of a fibrous web having a substantially uniform thickness, the concave section does not have a lower weight than the convex section, and the concave section has a higher fiber density than the convex section, and therefore it will 10 be difficult for moisture to be absorbed by the absorbent body. Then, moisture remains between the user's skin and the concave section, which causes a stuffy sensation. [0046] That is, the nonwoven fabric 10 in which the weight of the concave section 7 is lower than the weight of the convex section 6 can be used 15 as the surface sheet 2 by producing the nonwoven fabric 10 by spraying the fibrous web 11 with the fluid f (airflow processing) as in the present embodiment, and thus a sanitary napkin (absorbent article) in which a stuffy sensation and return of liquid is unlikely to occur can be provided. In addition, since in the concave section 7 not only moisture but also 20 liquid can pass easily, for example, even when a large amount of liquid is excreted, the liquid can be quickly forwarded to the absorbent body 4. Also, since resistance due to fibers is small in the concave section 7, liquid having a high viscosity can pass through the concave section 7 as well. 25 [0047] The nonwoven fabric 10 includes the concave section 7 and the convex section 6 formed along the MD direction, and is disposed as the surface sheet 2 such that the MD direction of the nonwoven fabric 10 serves as the longitudinal direction of the sanitary napkin 1. Since the surface sheet 2 is visible to the user, it is preferable in terms of appearance 30 that the concave section 7 and the convex section 6 are formed along the longitudinal direction. [00481 In addition, forming the surface of the surface sheet 2 in an irregular shape makes it possible that only the convex sections 6 contact the user's skin and the contact area between the user's skin and the 35 sanitary napkin is reduced, thereby mitigating the impact to the skin.

14 [0049] Also, forming the surface of the surface sheet 2 in an irregular shape makes it possible that liquid excreted onto the surface sheet 2 enters inside the concave sections 7 so that the convex sections 6 block scattering of the liquid in the width direction. In addition, since most 5 of fibers contained in the concave section 7 of the present embodiment are oriented in the width direction (CD direction) (FIG. 2A), liquid that has entered inside the concave section 7 is unlikely to scatter in the longitudinal direction as well. [0050] By producing the nonwoven fabric 10 (surface sheet 2) such that 10 the concave section 7 has a lower fiber density than the convex section 6 as the nonwoven fabric 10 of the present embodiment, liquid and moisture can be more easily forwarded to the absorbent body 4 due to the concave section 7, and return of liquid is further prevented by the convex section 6. By increasing the fiber density in the convex section 6, the convex 15 section 6 is unlikely to be crushed by an external pressure or the like. [0051] In particular, in the convex section 6, the lateral sections 62 to which fibers have been blown off by the fluid f have a high fiber density. Therefore, even when a small amount of liquid remains in the concave sections 7 after a large portion of excreted liquid has moved to the 20 absorbent body 4 due to the concave sections 7, such liquid can be forwarded to absorbent body 4 due to the capillary force of the lateral sections 62 adjacent to the concave sections 7. The back face side of the surface sheet 2 (nonwoven fabric 10) is a flat face, and the entire back face of the surface sheet 2 contacts the second sheet 3 (or the absorbent body 25 4). Therefore, liquid that has reached the back face side of the surface sheet 2 can smoothly move to the second sheet 3 and further to the absorbent body 4. Specifically, the liquid is unlikely to remain in the surface sheet 2, and as a result, giving a wet and sticky sensation to the user can be prevented. 30 Second Sheet 3 [0052] FIG. 4A is a perspective view of the second sheet 3, and FIG. 4B is a cross-sectional view of the second sheet 3. The sanitary napkin 1 of the present embodiment has the second sheet 3 between the surface sheet 2 and 35 the absorbent body 4. By setting the average fiber density of the second 15 sheet 3 higher than that of the surface sheet 2 so as to make the liquid drawing properties of the second sheet 3 better than those of the surface sheet 2, excreted liquid can be smoothly forwarded to the absorbent body 4. 5 [0053] Also, since the absorbent body 4 can be distanced from the user's skin by the thickness of the second sheet 3 by providing the second sheet 3, rewetting is prevented. However, from a viewpoint of preventing a stuffy sensation, the absorbent body 4 is distanced from the user' s skin by including the second sheet 3, and as a result, absorption of moisture becomes more 10 difficult. However, the surface of the surface sheet 2 of the present embodiment has an irregular shape, and the absorbent body 4 can be prevented from being excessively distanced from the user's skin due to the concave section 7. [0054] The second sheet 3 of the present embodiment is a nonwoven fabric 15 3' having a substantially uniform thickness, and includes a high density region 31 where the fiber density is higher than the average fiber density of the entire nonwoven fabric, and a low density region 32 where the fiber density is lower than the average fiber density. The high density region 31 and the low density region 32 are formed in a dispersed manner in a planar 20 direction of the nonwoven fabric 3', as shown in FIG. 4A, and as shown in FIG. 4B, the high density region 31 and the low density region 32 respectively penetrate from the surface side to the back face side in the thickness direction of the nonwoven fabric 3'. Further, in the high density region 31, the fiber density is higher in the back face side than in the surface 25 side. [0055] In the absorbent article of the present embodiment, the surface side of the nonwoven fabric 3' is disposed so as to face the surface sheet 2 side. Specifically, the high density region 31 and the low density region 32 penetrate from the surface sheet 2 to the absorbent body 4 side, and 30 in the high density region 31 the fiber density is higher in the absorbent body 4 side than in the surface sheet 2 side. [0056] Below, a method for producing the nonwoven fabric 3' used as the second sheet 3 will be described. FIGS. 5A to 5D show a method for producing the nonwoven fabric 3'. The nonwoven fabric 3' is obtained by 35 subjecting a fibrous web 34 in which one or plural types of heat-shrinkable 16 fibers having thermal adhesive properties are blended to heat processing in a state placed on a breathable net 33, and pressurizing the heat-adhered fibers with the breathable net 33 and the opposite face thereto. The production method of the nonwoven fabric 3' is different from the method 5 used for the above-stated surface sheet 2. [0057] Examples of the heat-shrinkable fiber used herein include an eccentric sheath-core multi-component fiber made up of two types of thermoplastic polymer materials having different shrinkage ratios, or side-by-side type multi-component fiber. Examples of the thermoplastic 10 polymer materials having different shrinkage ratios include a combination of ethylene/propylene random copolymer and polypropylene, a combination of polyethylene and ethylene/propylene random copolymer, and a combination of polyethylene and polyethylene terephthalate. [0058] First, a raw material obtained by blending a heat-shrinkable fiber 15 having thermal adhesive properties and a thermal adhesive fiber is spread with a carding machine (not shown) or the like, so that the fibrous web 34 of a predetermined thickness is continuously formed. Also, in the formed fibrous web 34, the heat-shrinkable fiber and the thermal adhesive fiber are not necessarily present in a uniform manner; a region where 20 the heat-shrinkable fiber is gathered and a region where the heat-shrinkable fiber is not gathered are formed. Note that the fibrous web may be formed of plural types of heat-shrinkable fiber. Also, the fibrous web may be formed by an air-laid method, instead of the carding method. 25 [0059] Then, as shown in FIG. 5A, the fibrous web 34 is heat-processed at a predetermined temperature in a state placed on the breathable net 33 (a plate-shaped support member having a flat surface, which has a mesh structure). That is, the fibrous web 34 is heat-processed in a state supported at the bottom side thereof. The predetermined temperature 30 refers to a temperature at which the heat-shrinkable fiber melts and undergoes thermal shrinkage. [0060] As a result, as shown in FIG. 5B, fibers in the fibrous web 34 adhere to other fibers while melting, and a fiber cloth 34' is formed in which fibers have undergone heat adhesion. Also on the face (free face) of the 35 fiber cloth 34' on the side opposite to the side supported by the breathable 17 net 33, an irregular structure (sea-island structure) is formed. On the other hand, the face (support face) of the fiber cloth 34' on the supported side is substantially flat along the surface of the breathable net 33. [0061] During heat processing, heat-shrinkable fibers of the fibrous web 5 34 on the free face side are not prevented from shrinking, and therefore the heat-shrinkable fibers shrink freely in the planar direction while tangling with surrounding fibers (such as a thermal adhesive fiber). Specifically, a convex section 35 in the irregular structure is a region where heat-shrinkable fibers are gathered, and includes a large number 10 of fibers tangled with heat-shrinkable fibers during thermal shrinkage thereof. For this reason, the weight of the convex section 35 is greater than that of the average weight of the fiber cloth 34'. In contrast, a small amount of heat-shrinkable fibers are originally present in a concave section 36, which is a region where thermal adhesive fibers have been 15 tangled with surrounding heat-shrinkable fibers and relocated outside. Therefore the weight of the concave section 36 is lower than the stated average weight. In addition, since fibers present in the concave section 36 are relocated to the convex section 35 due to heating processing, the convex section 35 and the concave section 36 are formed adjacent to each 20 other. [0062] After that, as shown in FIG. 5C, the free face side of the fiber cloth 34' on which the irregular structure is formed is pressed in the thickness direction thereof such that the convex sections 35 are crushed. By pressing the fiber cloth 34' with a definite strength to a thickness 25 equal to or smaller than the thickness of the concave section 36 at this time, the nonwoven fabric 3' having a substantially uniform thickness can be obtained, as shown in FIG. 5D. In addition, if the fiber cloth 34' is pressed in a state heated at a predetermined temperature at the time of pressing, the convex sections 35 are easily crushed, and thus 30 the free face side, which has been irregular, can be made flatter. The region formed as a result of the convex section 35 being crushed becomes the high density region 31, while the region that was the concave section 36 becomes the low density region 32. Furthermore, since the convex section 35 and the concave section 36 are formed adjacent to each other, 35 the high density region 31 and the low density region 32 are also present 18 adjacent to each other in the planar direction. [0063] Also, since the high density region 31 is formed by pressing the convex section 35 on the free face side of the fiber cloth 34', the fiber density is higher in the free face side than in the support face side. 5 Specifically, the free face in FIG. 5D corresponds to the back face of the nonwoven fabric 3' shown in FIG. 4B stated above, and the support face in FIG. 5D corresponds to the surface of the nonwoven fabric 3' shown in FIG. 4B stated above. [0064] It should be noted that in order to favorably obtain the nonwoven 10 fabric 3' in which the high density region 31 and the low density region 32 are dispersed in the planar direction, and the high density region 31 and the low density region 32 penetrate from the free face to the supported face, the weight of the convex section 35 (2X g/m 2 ) at the time when the fibrous web 11 has been heat-processed (FIG. 5B) can be set to 15 at least twice the weight of the concave section 36 (X g/m 2 ), and the fibrous web 34 can be pressed to a thickness equal to or less than the thickness of the concave section 36. For this purpose, it is possible to form a desired irregular structure of fiber by controlling "fiber properties" and "production conditions". 20 Absorbent Body 4 [0065] FIG. 6A shows a top view of the absorbent body 4. FIG. 6A virtually indicates the external shape of the sanitary napkin 1 with a dotted line. The absorbent body 4 is made up of an absorbent body material 43 and a 25 covering material that covers the absorbent body material 43. The absorbent body material 43 is made up of an absorbent fiber 44 and a superabsorbent resin 45. As an example of the absorbent fiber 44, pulp fiber (pulp pulverized in fibers) is used, and pulp fibers are accumulated in a sheet form for use. As an example of the superabsorbent resin 45, 30 granular superabsorbent polymer (hereinafter referred to as "SAP") is used. In the absorbent body 4 of the present embodiment, SAP is densely gathered in portions of the absorbent body material 43, and is not evenly dispersed (details will be described later). Note that the absorbent body material 43 may include, other than pulp fiber, cellulose such as cotton, 35 regenerated cellulose such as rayon or fibril rayon, semisynthetic 19 cellulose such as acetate or triacetate, a fibrous polymer, a thermoplastic hydrophobic chemical fiber, or the like. [0066] The covering material that covers the absorbent body material 43 is a sheet having liquid permeability whose mesh is finer than the grain 5 size of SAP, and has a function of preventing SAP or pulp fibers from leaking outside the covering material. Examples of the covering material include thin paper such as tissue paper. [0067) In the absorbent body 4 of the present embodiment, in order to integrate the covering member and the absorbent body material 43, a 10 predetermined portion of the absorbent body 4 is compressed so as to form an embossment at that portion. [0068] In the sanitary napkin 1 including such an absorbent body 4, excreted liquid is absorbed by the absorbent fiber 44 (pulp fiber accumulated in a sheet form) and penetrates to the inside of the absorbent 15 body material 43. Thereafter, as a result of liquid being repeatedly excreted, the liquid inside the absorbent body material 43 scatters inside the absorbent body material 43, and is finally collected by SAP (superabsorbent resin 45). SAP has a property of swelling when moisture is collected therein, and has excellent moisture-absorbing properties. 20 Therefore, SAP has a main role of absorbing moisture before it collects liquid, and an effect of preventing a stuffy sensation is achieved due to SAP. Also in the surface sheet 2 of the present embodiment, the absorbent body 4 easily absorbs moisture with the concave sections 7 having a low weight. Therefore moisture is absorbed further by providing SAP 25 in the absorbent body 4. [0069] In the absorbent body 4 of the present embodiment, as shown in FIG. 6A, a bulging section 41 that bulges to the skin face side is formed in a portion located in the central section in the longitudinal direction and the width direction. The bulging section 41 is formed in an oval shape, 30 and when the user is wearing the sanitary napkin 1, conforming to the shape of the groin of the user so that the absorbent body 4 fits closely to the groin via the surface sheet 2 and the second sheet 3, thereby preventing liquid leakage. [0070] The skin face side of the absorbent body 4 and the second sheet 35 3 are joined by a hot-melt adhesive HMA, and the absorbent body 4, the 20 second sheet 3 and the surface sheet 2 are further firmly joined with a deep channel section 47 formed by the deep-channel embossing of pressing in the thickness direction using a high-temperature pressing member. As shown in FIG. 6A, the deep channel section 47 is formed in a region 5 surrounding the bulging section 41, and a region spanning from the front to the rear in the longitudinal direction of the sanitary napkin 1, on both sides of the bulging section 41. Note that in the deep channel section 47, a shallow bottom section and a deep bottom section whose channel depths differ from each other are alternately disposed. Due to this sort of deep 10 channel section 47 being formed, when the sanitary napkin 1 is worn, the surface side of the sanitary napkin 1 is easily bent in a mountain form along the body. As a result, the sanitary napkin 1 can be closely fit to a groove portion of the body or the like, so that liquid is unlikely to leak. Also, since liquid excreted to the bulging section 41 enters 15 the deep-channel section 47, it is possible to prevent liquid from scattering in the surface direction of the sanitary napkin 1. [0071] FIG. 6B is a cross-sectional view of an interspersed section 48. The interspersed sections 48 are areas where SAP (superabsorbent resin) is densely gathered, and are formed in an oval shape. The interspersed 20 sections 48 are disposed further in the front end side and rear end side than the bulging section 41. Embossing 46 is performed on the portion corresponding to the outer circumference of the interspersed section 48. Note that more of the interspersed sections 48 are present in the rear end section than in the front end section. This is because liquid tends 25 to move to the rear end side (lower back side) in the case where the user lies down for sleep. [0072] While SAP and pulp fiber are mixed in the interspersed section 48, pulp fibers are densely gathered in a substantially even manner in the absorbent body material 43 other than the interspersed sections 48, where 30 SAP is not contained. The weight of pulp fibers in the interspersed section 48 is lower than the weight of pulp fibers in the portion other than the interspersed sections. This is because SAP swells when it absorbs moisture. If the weight of pulp fibers in the interspersed section 48 is similar to that in the region other than the interspersed sections, 35 SAP swells when SAP absorbs moisture and accordingly the interspersed 21 section swells in the thickness direction. In such a case, part of the absorbent body 4 that has been substantially flat bulges, and causes the user to feel a bump (an unpleasant sensation) . That is, by setting the weight of pulp fiber in the interspersed section 48 lower than that in 5 the region other than the interspersed sections, a space is secured in advance preparing for swelling of SAP. [0073] Also, by gathering SAP in some portions (providing interspersed sections 48) instead of evenly dispersing SAP in the absorbent body material 43, it is possible to prevent a phenomenon (blocking phenomenon) 10 in which SAP particles collect liquid and join together so that moisture is prevented from scattering in the absorbent body material 43. When the blocking phenomenon occurs, moisture that has penetrated to the absorbent body material 43 remains in the skin face side thereof, which may deteriorate the absorbing ability of the sanitary napkin 1. Then, liquid 15 remains in the surface sheet 2 or second sheet 3, which makes it impossible to keep the surface sheet 2 in a dry condition, and as a result, a stuffy sensation is caused easily. [0074] Furthermore, in the present embodiment, the bulging section 41 does not include the interspersed section 48. The reason is as follows. Since 20 once SAP has absorbed liquid it is unlikely to release the liquid, it is necessary for the bulging section 41 that is required to absorb liquid repeatedly to move liquid forward or backward, without holding liquid. In such a manner, it becomes possible to effectively use the absorbent body 4 over the entire face thereof. 25 [0075] The sanitary napkin 1 is folded in three at two folding line positions at the time of product wrapping. As shown in FIG. 6A, the interspersed sections 48 are present at portions corresponding to folding line positions used for folding. Since the interspersed section 48 has a low pulp fiber content and a low rigidity, the sanitary napkin 1 can 30 be folded easily by providing the interspersed sections 48 at the folding line positions. Other Constituent Elements [0076] The back face sheet 5 is joined to the back face side (side opposite 35 to the skin face) of the absorbent body 4 with hot-melt adhesive HMA.

22 Also, on the skin face side of the absorbent body 4, from a position slightly overlapping both side sections of the absorbent body 4 to the back face sheet 5, the side sheet 8 is joined with hot-melt adhesive. A round sealing process is performed in which the outer edge section of the sanitary napkin 5 1 is hot-melt bonded at a low temperature, so that the second sheet 3 and the absorbent body 4 are held between the surface sheet 2 and the back face sheet 5. Back Face Sheet 5 10 [0077] The back face sheet 5 is a liquid-impermeable sheet member. The back face sheet 5 is formed from a film sheet constituted of a resin such as polyethylene, polypropylene, or the like. The back face sheet 5, on the side of the opposite face of the sanitary napkin 1, is formed sufficiently wider than the absorbent body 4, and the entire circumference 15 of the outer edge section thereof is positioned to the outside of the outer edge section of the absorbent body 4. Adhesive is applied to the back face side of the back face sheet 5, and the sanitary napkin 1 is attached to the inside of the undergarment by adhesive interposed between the back face sheet 5 and the undergarment. 20 [0078] Also, on both sides in the width direction, wing sections 9 are formed protruding to the outside in the width direction. When the sanitary napkin 1 is worn, the wing sections 9 are, in a state folded back to the opposite face side, fixed to the undergarment. [0079] The back face sheet according to the present embodiment is a 25 liquid-impermeable sheet formed from thermoplastic fiber of polyethylene, polypropylene, or the like, but it is also possible to use a sheet member in which thin paper, nonwoven fabric, or the like has been layered and that includes a thermoplastic and liquid-impermeable sheet. 30 Side Sheet 8 [0080] The side sheets 8 overlap a portion of the surface sheet 2 (more precisely, both end sections in the width direction of the surface sheet 2), and are provided on the skin face side of the sanitary napkin 1 in both end sections in the width direction of the sanitary napkin 1. The 35 side sheets 8 are formed from an appropriate nonwoven fabric, such as 23 an air-through nonwoven fabric formed with a synthetic resin fiber or a spun-bonded nonwoven fabric, or a nonwoven fabric made up of spunbond-meltblown-spunbond layers. 5 Working Mechanism of the Sanitary Napkin 1 [0081] FIGS. 7A to 7D show how liquid 50 that has been excreted onto the sanitary napkin 1 is absorbed into the sanitary napkin 1. Note that FIGS. 7A to 7D show a cross-sectional view of the bulging section 41 that does not contain the interspersed section 48. 10 [0082] As shown in FIG. 7A, liquid 50 such as menstrual blood is excreted onto the surface sheet 2 of the sanitary napkin 1. Then, the excreted liquid 50 first enters the concave section 7 between the convex sections 6. Therefore, scattering of the liquid 50 in the width direction in the surface sheet 2 can be blocked by the convex sections 6. In this manner, 15 by forming the surface of the surface sheet 2 in an irregular shape and reducing the scattering area of the liquid 50 in the surface sheet 2, the contact area of the surface sheet 2 that is wet with the liquid 50 with the user's skin can be reduced. Also, since the surface sheet 2 is visible to the user, a smaller scattering area of the liquid 50 (menstrual 20 blood) is preferable from a visual perspective as well. [0083] In the present embodiment, the average fiber density is adjusted so as to be higher in the second sheet 3 than in the surface sheet 2, and therefore a large portion of the liquid 50 in the surface sheet 2 passes through the surface sheet 2 where resistance due to fibers is small, 25 and can quickly move to the second sheet 3. Especially, the concave section 7 of the surface sheet 2 has a shorter distance to the second sheet 3 compared with the convex section 6, and also has a lower fiber density than the convex section 6. Therefore, the concave section 7 can forward the liquid 50 to the second sheet 3 easily. 30 [0084] Thereafter, the liquid 50 that has reached the surface side of the second sheet 3 passes through the inside of the low density region 32 of the second sheet 3 and moves to the absorbent body 4, as shown in FIG. 7B. Since the low density region 32 of the second sheet 3 penetrates the second sheet 3 in the thickness direction, the liquid 50 can be quickly 35 forwarded to the absorbent body 4. For this reason, scattering of the 24 liquid 50 in the planar direction can be suppressed in the second sheet 3 similarly to the surface sheet 2. Even liquid having a high viscosity can pass through the concave section 7 of the surface sheet 2 or the low density region 32 of the second sheet 3, and move to the absorbent body 5 4. [0085] Then, after a large portion of the liquid 50 has moved to the absorbent body 4, as shown in FIG. 7C, the liquid 50 remaining on the surface sheet 2 is drawn to the inside of the surface sheet 2 due to the capillary force of the lateral sections 62 (convex section 6) where the 10 fiber density is high. The liquid remaining in the surface sheet 2 is drawn to the second sheet 3 (high density region 31) due to the capillary force of the high density region 31 of the second sheet 3. Furthermore, since the fiber density in the high density region 31 is higher in the absorbent body 4 side than in the surface sheet 2 side, the drawn liquid 15 50 can be forwarded to the absorbent body 4 due to the capillary force. Note that since pulp fibers are layered in the absorbent body 4, the fiber density is higher in the absorbent body 4 than in the high density region 31. The liquid 50 remaining in the low density region 32 of the second sheet 3 can also move to the absorbent body 4 due to the capillary force 20 of the high density region 31. [0086] That is, in the sanitary napkin 1 (absorbent article) of the present embodiment, liquid quickly moves to the absorbent body 4 without scattering in the planar direction, and liquid is unlikely to remain in the surface sheet 2 and the second sheet 3. With such a sanitary napkin 25 1, excreted liquid reliably moves to the absorbent body 4, and the surface sheet 2 and the second sheet 3 are dried to a predetermined condition after the liquid is excreted. Therefore, soiling the skin of the user or giving the user discomfort (a wet and sticky sensation) can be prevented. In addition, liquid can be repeatedly excreted. 30 [0087] In this manner, liquid that has moved to the absorbent body 4 scatters in the planar direction as liquid is repeatedly excreted. Especially, the surface sheet 2 and the second sheet 3 of the present embodiment have good liquid forwarding properties (because liquid is unlikely to scatter in the planar direction), and a large portion of liquid 35 is absorbed by the bulging section 41 that contacts an excreting opening 25 of the body. For this reason, liquid in the bulging section 41 moves forward and backward in the bulging section 41, and finally, is absorbed by the superabsorbent resin (SAP) of the interspersed section 48 to be retained there. Since SAP can hold a large amount of liquid as described 5 above, even if liquid is repeatedly excreted, there is little possibility for overflowing of liquid. [0088] Also, once the superabsorbent resin (SAP) has absorbed liquid, the superabsorbent resin is unlikely to release the liquid. Therefore, liquid is unlikely to return to the surface sheet 2 side (rewet) in the 10 absorbent body 4 including SAP. In particular, in the present embodiment, the absorbent body 4 and the user's skin are distanced from each other as much as possible by providing the convex sections 6 in the surface sheet 2, such that liquid does not return to the surface sheet 2 side. Therefore, it is possible to provide a sanitary napkin 1 in which returning 15 of liquid to the surface sheet 2 side is less likely, by providing the superabsorbent resin SAP in the absorbent body 4. [0089] Of the absorbent body material 43, while the absorbent fiber 44 (pulp fiber) absorbs moisture, the superabsorbent resin (SAP) has better hygroscopic properties. For this reason, until liquid absorbed by the 20 absorbent body 4 (bulging section 41) reaches the interspersed section 48 including SAP, moisture is absorbed mainly by the interspersed section 48 (SAP) so that a stuffy sensation is unlikely to be caused. In particular, in the present embodiment, the concave section 7 having a low weight (low fiber density) is provided in the surface sheet 2 such that moisture is 25 easily absorbed. Therefore it is possible to provide a sanitary napkin 1 (absorbent article) that is unlikely to cause a stuffy sensation, by providing the interspersed section 48 where SAP is densely gathered in the absorbent body 4. 30 Second Embodiment [0090] In the foregoing embodiment, the second sheet 3 is disposed between the surface sheet 2 and the absorbent body 4. However, there is no limitation to this. For example, with an absorbent article such as that of the second embodiment (not shown), which includes a surface sheet 2 35 having an irregular surface in which the concave section has a lower weight 26 than the convex section, and an absorbent body 4 including an interspersed section where superabsorbent resin is densely gathered, it is possible to provide an absorbent article that is unlikely to cause a stuffy sensation without disposing the second sheet 3 between the surface sheet 5 2 and the absorbent body 4. [0091] In the case of the absorbent article of the second embodiment, since it is possible to shorten the distance between the absorbent body 4 (especially SAP) and the concave section 7 of the surface sheet 2 by the thickness of the second sheet 3 compared with the aforementioned absorbent 10 article. Therefore, it is possible to absorb a larger amount of moisture. As a result, the absorbent article of the second embodiment causes less of a stuffy sensation than the aforementioned absorbent article. [0092] However, return of the liquid is less likely in the aforementioned absorbent article, since the aforementioned absorbent article can 15 distance the absorbent body 4 from the user's skin by the thickness of the second sheet 3 further than the absorbent article of the second embodiment. [0093] Also, as the foregoing embodiment, it is possible to draw liquid remaining in the surface sheet 2 inside the second sheet 3 so as to forward 20 the liquid to the absorbent body 4 by providing the second sheet 3. Accordingly, as a modified example of the second embodiment, it is possible to propose an absorbent article (not shown) in which the second sheet 3 is provided in the region contacting the excreting opening of body (e.g., bulging section 41) only, and the second sheet 3 is not disposed on the 25 front and rear sides of the absorbent article where the interspersed sections 48 are disposed. In such an absorbent article, liquid can move to the absorbent body 4 without the liquid remaining in the surface sheet 2 due to the second sheet 3 in the region where the liquid is excreted, and in the regions on the front and rear sides of the absorbent article 30 where the second sheet 3 is not disposed, the distance between moisture and the absorbent body 4 (SAP) can be shortened. Therefore, causing a stuffy sensation can be less likely. Evaluation Test of Absorbent Article 35 [0094] The aforementioned surface sheet andsecondsheet (nonwoven fabric) 27 were actually produced and rewetting properties thereof were evaluated. First, the method for evaluating the rewetting properties will be described. 5 Evaluation Method of Rewetting Properties [0095] Following instruments are used for measurement. 1) Artificial menstrual blood 2) Auto-burette (Metrohm Corp., model No. 725) 3) Scale 10 4) Perforated acrylic board (including an opening of 40 mm x 10 mm in the center; length x width = 200 mm x 100 mm; weight: 125 g) 5) Acrylic board (used to apply the load of weight evenly to the filter paper; length x width = 100 mm x 70 mm; weight: 45 g) 6) Weight 15 7) Stopwatch 8) Filter paper (Manufactured by Advantech Toyo, No. 2; length x width = 50 mm x 35 mm) The artificial menstrual blood is prepared by mixing the followings into one liter of ion-exchanged water. 20 (1) glycerin (80 g), (2) carboxymethylcellulose sodium (NaCMC) (8 g), (3) sodium chloride (NaCl) (10 g), (4) sodium hydrogen carbonate (NaHCO3) (4 g), (5) Pigment: Red No. 102 (8 g), (6) Pigment: Red No. 2 (2 g), and (7) Pigment: Yellow No. 5 (2 g). [0096] The evaluation procedure is as follows: 25 1) The weight of ten sheets of filter paper is measured. --- A 2) The acrylic board is placed on an evaluated object (nonwoven fabric + absorbent body) such that the center of the opening of the acrylic board is matched to the center of the evaluated object. 3) The nozzle of the auto-burette is positioned 10 mm above the acrylic 30 board. 4) Artificial menstrual blood is dripped (rate: 95 ml/min, drip amount: 6 ml). 5) Upon passage of one minute immediately after the artificial menstrual blood has drained from the surface of the nonwoven fabric, ten sheets 35 of filter paper are placed matched to the center of the surface sheet, 28 and the acrylic board (no opening) and weight are superposed thereon so as to apply a total load of 50 g/cm 2 . 6) Upon passage of one minute, the weight and the acrylic board are removed and the weight of the filter paper is measured. --- B 5 Based on the measurement results A and B, the rewet rate is calculated. The rewet rate (%) = ((B-A) x 100) / (drip amount: 6ml) Evaluation of Nonwoven fabrics [0097] The production conditions, evaluation results and the like of 10 nonwoven fabrics (surface sheet, second sheet) actually produced will be described below. FIG. 8 is a table describing constituent fibers of nonwoven fabrics used for evaluation. As shown in the table in FIG. 8, a comparative surface sheet a (a nonwoven fabric produced by the air-through production method), a working surface sheet b (a nonwoven 15 fabric 10 produced by the airflow processing illustrated in FIG. 3A as described above) , a comparative second sheet c (a nonwoven fabric produced by the air-through production method), and a working second sheet d (the nonwoven fabric 3' whose production method was illustrated in FIG. 5 as described above) were produced. Then, the rewet rate of these evaluated 20 objects obtained by combining these four types of nonwoven fabrics and an absorbent body was measured. [0098] It should be noted that the same absorbent body was used in common, which is produced by wrapping 500 g/m 2 of fluff pulp with a 15 g/m 2 of tissue (thin paper), and being subjected to flat pressing (not including 25 SAP) . The density of the absorbent body is adjusted to 0.09 g/cm 3 . Then, hinge pressing is performed so that the nonwoven fabric (the surface sheet and the second sheet) does not rise from the absorbent body. The hinge is convex-shaped on the inside, and the narrowest portion thereof is 38 mm long. While adhesive is applied to the hinge portion, the portion that 30 absorbs artificial menstrual blood is not subjected to the hinge pressing. [0099]Also, the air-through production method is a method in which a fibrous web is placed on a breathable net or drum, and is blown with a hot air, such that the intersections of the constituent fibers undergo heat adhesion, thereby forming a nonwoven fabric. The air-through 35 nonwoven fabric has a substantially flat surface, and a substantially 29 uniform fiber density over the entire region of the nonwoven fabric. [0100] FIG. 9 shows the construction of evaluated objects (nonwoven fabric + absorbent body) and results of measuring the rewet rate. The rewet rate was measured for the following five types of evaluated objects. 5 (1) Comparative example 1 = Comparative surface sheet a + Absorbent body (2) Comparative example 2 = Comparative surface sheet a + Comparative second sheet c + Absorbent body (3) Comparative example 3 = Comparative surface sheet a + Working second sheet d + Absorbent body 10 (4) Working example 1 = Working surface sheet b + Absorbent body (5) Working example 2 = Working surface sheet b + Working second sheet d + Absorbent body [0101] By comparing the rewet rates of the comparative example 1 and the working example 1, it is understood that the rewet rate of the working 15 example 1 is lower than that of the comparative example 1 (-20.1%) . That is, rewetting is less likely in the working surface sheet b (the aforementioned nonwoven fabric 10 in FIG. 2A) than in the comparative surface sheet a. This is because, as indicated by the table in FIG. 8, the working surface sheet b (convex section) is thicker than the 20 comparative surface sheet a, so that the absorbent body and the filter paper (skin in actuality) can be distanced from each other. [0102] Also, while the comparative surface sheet a has a flat shape, the working surface sheet b has an irregular shape. Therefore, the working surface sheet b can achieve a smaller contact area with the filter paper 25 (skin) than the comparative surface sheet a, and accordingly, it is understood that the working example 1 has a lower rewet rate than the comparative example 1. [0103] Next, by comparing the rewet rates of the working example 1 and the working example 2 (or the comparative example 1 and the comparative 30 example 2), it is understood that the rewet rate of the working example 2 is lower than that of the working example 1 (the rewet rate of the comparative example 2 is lower than that of the comparative example 1) . That is to say, rewetting is less likely when the second sheet is provided between the surface sheet and the absorbent body, since the absorbent 35 body and the filter paper (skin in actuality) can be distanced from each 30 other. However, as described in the second embodiment, from the viewpoint of preventing a stuffy sensation, when the second sheet is provided, the absorbent body and skin (moisture) are distanced from each other, and therefore a stuffy sensation is more likely to be caused compared with 5 the case where the second sheet is not provided. [0104] Furthermore, by comparing the rewet rates of the comparative example 2 and the comparative example 3, it is understood that the rewet rate of the comparative example 3 is lower than that of the comparative example 2. That is to say, rewetting is less likely in the working second 10 sheet d (FIG. 4B) in which the high density region and the low density region penetrate in the thickness direction than in the comparative second sheet c in which the fiber density is substantially uniform over the entire region thereof. In this evaluation method of the rewetting properties, in addition to return of liquid from the absorbent body, the liquid 15 remaining in the second sheet or the surface sheet also returns to the surface sheet due to application of pressure (weight), and is absorbed by the filter paper. In other words, in the working second sheet d, as described above, liquid can be reliably forwarded to the absorbent body due to the capillary force of the high density region so that the liquid 20 is unlikely to remain in the second sheet or the surface sheet. Asa result, the rewet rate is reduced. [0105] Based on this nonwoven fabric evaluation test, it was understood that the rewet rate can be reduced by using the nonwoven fabric subjected to the airflow processing (FIG. 3A) as the surface sheet instead of the 25 nonwoven fabric subjected to the air-through processing, and by disposing the second sheet between the surface sheet and the absorbent body. Furthermore, the rewet rate can be further reduced by using the nonwoven fabric in which the high density region and the low density region penetrate in the thickness direction as the second sheet. 30 Third Embodiment (Modified Example of Surface Sheet) [0106] FIG. 10A shows a surface sheet 51 of a third embodiment. In this surface sheet 51 (nonwoven fabric), convex sections 6A and 6B adjacent to each other in the width direction have different heights. With such 35 a surface sheet 51, the contact area between the user's skin and the surface 31 sheet 51 can be reduced without decreasing the number of convex sections. That is, the surface sheet 51 of the third embodiment can achieve a reduced contact area between the skin and the surface sheet 51 without significantly reducing the strength of the surface sheet 51. 5 [0107] It should be noted that such a surface sheet 51 can be produced by, for example, changing the areas (air volume) of the spraying openings 16 lined up in the CD direction shown in FIG. 3A. Fourth Embodiment (Modified Example of Surface Sheet) 10 [01081 FIG. 10B shows a surface sheet 52 of a fourth embodiment. The concave section 7 of the surface sheet 52 is provided with an opening section 53. Liquid that has entered the concave section 7 can be forwarded to the absorbent body 4 (second sheet 3) more rapidly than in the above-described surface sheet 2 due to the opening section 53. Also, a 15 large amount of liquid or liquid having a high viscosity can also smoothly move to the absorbent body 4 due to the opening section 53. However, since the opening section 53 is provided in the concave section 7, the strength is reduced compared with the above-described surface sheet 2. 20 Also, while the opening section 53 shown in FIG. 10B is an opening that penetrates in the thickness direction, a depression may be formed in the concave section 7. In such a case as well, liquid can be rapidly forwarded to the absorbent body 4. [0109] Note that the surface sheet 52 including such an opening section 25 53 can be produced by, for example, disposing a non-breathable plate or the like on the breathable support member 12 at equal intervals in the MD direction (not shown) . The amount of fibers on the non-breathable plate is smaller than that in other regions, and therefore all fibers (or most of fibers) on the plate is blown off to the region that is to become the 30 convex section by the fluid f. As a result, the opening section 53 is formed. Other Embodiments [0110] In the surface sheet 2 of the foregoing embodiments, while the 35 convex sections 6 are formed at equal intervals in the width direction, 32 this is not a limitation. The convex sections 6 may be formed at different intervals. [0111] In the foregoing embodiments, while the nonwoven fabric in which the high density region 31 and the low density region 32 penetrate in 5 the thickness direction is used as the second sheet 3, this is not a limitation. For example, the nonwoven fabric (comparative second sheet c) produced by the air-through production method may be used as the second sheet 3. However, from the rewetting evaluation test results shown in FIG. 9, it is understood that rewetting is less likely in the working 10 second sheet d than in the comparative second sheet c. [0112] In the absorbent body 4 of the foregoing embodiments, the absorbent body material 43 of the portion other than the interspersed section 48 does not contain the superabsorbent resin (SAP). However, this is not a limitation. The absorbent body material 43 of the portion other than 15 the interspersed section 48 may contain SAP. [0113] The above embodiments are for the purpose of elucidating the understanding of the invention, and are not construed as limiting the invention in any way. The invention can be modified or improved without departing from the gist thereof, and any equivalents thereof are of course 20 included in the scope of the invention.

Claims (5)

1. An absorbent article comprising: a liquid-permeable surface sheet; 5 a liquid-impermeable back face sheet; and a liquid-retaining absorbent body disposed between the surface sheet and the back face sheet, the surface sheet including a concave section and a convex section so that the surface thereof has an irregular shape, the concave section 10 having a lower weight per unit area than the convex section, the absorbent body including an interspersed section where a superabsorbent resin is densely gathered.

2. An absorbent article according to claim 1, 15 wherein the absorbent body includes an absorbent fiber, and a fiber density of the absorbent fiber in the interspersed section is lower than a fiber density of the absorbent fiber in the absorbent body other than the interspersed section. 20

3. An absorbent article according to claim 1 or claim 2, wherein a content rate of the interspersed section is higher in an end section in a longitudinal direction of the absorbent body than in a central section in the longitudinal direction of the absorbent body. 25

4. An absorbent article according to any of claims 1 to 3, comprising a liquid-permeable second sheet made up of a nonwoven fabric disposed between the absorbent body and the surface sheet, wherein the second sheet includes a high density region having a fiber density higher than an average fiber density of the nonwoven fabric forming 30 the second sheet, and a low density region having a fiber density lower than the average fiber density, the high density region and the low density region penetrating from the surface sheet side to the absorbent body side in the thickness direction of the nonwoven fabric. 35

5. An absorbent article according to any of claims 1 to 4, 34 wherein the surface sheet is a nonwoven fabric formed by a fiber aggregate whose surface has an irregular shape as a result of having been sprayed with a fluid.