Abstract:
The present invention addresses the problem of improving quick-drying properties of a top sheet at a part that often contacts with the skin of a wearer. A top sheet ( 10 ) for absorbent articles comprises an upper layer sheet ( 11 ), a lower layer sheet ( 12 ), multiple bonded parts ( 40 ) at which the sheets ( 11, 12 ) are bonded to each other, and multiple unbonded parts ( 50 ) which are surrounded by the multiple bonded parts ( 40 ). Each of the unbonded parts ( 50 ) has a larger area ( 51 ) that has a relatively large area and a smaller area ( 52 ) that has a relatively small area and is extended in one direction from the larger area ( 51 ). The upper layer sheet ( 11 ) is protruded convexly in the larger areas ( 51 ) and the smaller areas ( 52 ).

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a top sheet provided on a surface of an absorbent article directly coming into contact with a skin of a wearer. More specifically, the invention relates to a top sheet obtained by joining a plurality of stacked sheet members using embossing. 
       BACKGROUND ART 
       [0002]    A tape-type disposable diaper, a pants-type disposable diaper, a urine pad, a panty liner, a light incontinence pad, a sanitary napkin, etc. has been known as an absorbent article installed on a crotch of a wearer. In such an absorbent article, a surface facing a skin of the wearer (skin facing surface) includes a top sheet. The top sheet is a sheet member that continuously comes into contact with the skin of the wearer. Thus, in general, a material causing low skin irritation is used. For example, a material causing low irritation is considered to be preferable for the top sheet. Examples of the irritation include mechanical irritation generated due to contact or friction with the skin, irritation due to environmental deterioration such as mustiness at a position at which the absorbent article is worn, chemical irritation generated when a hydrophilizing agent used for the top sheet or excreta touches the skin, etc. 
         [0003]    In addition, a conventionally known scheme, an uneven embossing pattern is formed by performing embossing on the top sheet for the absorbent article to reduce a contact area with the skin, thereby reducing mechanical irritation due to friction, etc. In addition, since a gap is generated between the skin and the top sheet when embossing is performed on the top sheet, it is possible to expect an effect that mustiness is partially relieved. Further, when embossing is performed on the top sheet, excreta such as urine flows along unevenness and easily diffuses, and absorbency of the top sheet is considered to be improved by diffusion effect thereof. In this way, various embossing patterns formed on the top sheet have been devised in order to further improve a low irritation property, a mustiness relief effect, and a liquid diffusion effect of the top sheet (Patent Literatures 1 to 3). 
       CITATION LIST 
     Patent Literature 
       [0004]    Patent Literature 1: JP 2009-000512 A 
         [0005]    Patent Literature 2: JP 2004-000466 A 
         [0006]    Patent Literature 3: JP 2009-160032 A 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0007]    Patent Literatures 1 to 3 disclose a conventional embossing pattern in which a region surrounded by three or more joining portions is set to a protrusion. In the conventional embossing pattern, the joining portions are formed at positions of latticed apexes of a triangle, a rectangle, or another polygon. For this reason, in the conventional embossing pattern, for example, a protrusion surrounded by a plurality of joining portions has a simple shape such as a regular triangle, a square, a regular hexagon, etc. In this way, when the protrusion of the embossing pattern has a simple shape such as a square, and when a liquid excreted by the wearer touches the top sheet, the top sheet evenly diffuses the liquid in every direction. When the liquid is evenly diffused in every direction, there is a merit that liquid absorption efficiency is enhanced. 
         [0008]    However, when the liquid touching the top sheet is diffused all around the protrusion, a region of the top sheet touched by the liquid is evenly damp in a wide range. As a result, there has been a problem that the region damped by absorbing the liquid rarely dries as a whole. In other words, when the liquid evenly diffuses around the protrusion, the region damped by this liquid almost simultaneously dries. However, there is a desire to rapidly dry at least a region easily touching the skin of the wearer by priority when the top sheet absorbs the liquid. 
         [0009]    In this regard, an issue to be solved by the invention is to provide a top sheet in which a quick drying property of a region that easily touches the skin of the wearer may be enhanced. 
       Solution to Problem 
       [0010]    As a result of a keen examination of solution to the above-mentioned problem, the inventors of the invention have determined to form a plurality of joining portions around a non-joining portion that convexly swells such that the non-joining portion includes a large region having a large area and a small region having a small area which extends in one direction from the large region. In this way, when a liquid touches a top sheet, the liquid may be rapidly moved from the large region to the small region, and the large region easily touched by a skin of a wearer may be rapidly dried by priority. Since the liquid flows from the large region into the small region, there is a possibility that a drying time of the small region may increase. However, it is possible to enhance at least a quick drying property of the large region. When a drying time of the large region having the large area shortens, a feeling of wearing an absorbent component including the top sheet is improved. In addition, the inventors have conceived that the problem of the conventional invention may be solved based on the above-described information, and completed the invention. Specifically, the invention has configurations below. 
         [0011]    A first aspect of the invention relates to a top sheet  10  of an absorbent article. 
         [0012]    The top sheet  10  of the invention includes an upper layer sheet  11 , a lower layer sheet  12 , a plurality of joining portions  40 , and a plurality of non-joining portions  50 . 
         [0013]    The upper layer sheet  11  and the lower layer sheet  12  are stacked on each other. The upper layer sheet  11  is positioned on a side that directly touches the skin of the wearer, and the lower layer sheet  12  is disposed on a rear side of the upper layer sheet  11 , and does not directly touch the skin of the wearer. 
         [0014]    The plurality of joining portions  40  joins the upper layer sheet  11  and the lower layer sheet  12  to each other. 
         [0015]    Each of the plurality of non-joining portions  50  is surrounded by a plurality of joining portions  40 . 
         [0016]    Herein, each of the non-joining portions  50  includes a large region  51  having a relatively large area, and a small region  52  having a relatively small area and extending in one direction from the large region  51 . The upper layer sheet  11  convexly swells in the large region  51  and the small region  52 . 
         [0017]    The large region  51  and the small region  52  may hold spaces therein, and insides thereof may be filled with fiber. 
         [0018]    As in the above-described configuration, in the invention, the non-joining portion  50  surrounded by the plurality of joining portions  40  has a shape that includes only the large region  51  having the large area and the small region  52  having the small area. In this way, the liquid touching the top sheet  10  may be rapidly moved from the large region  51  to the small region  52 . For example, in order to shorten a drying time of the liquid, the large region  51  may be swelled higher than the small region  52 , or a fiber density (fiber filling rate) of the small region  52  may be set to be higher than that of the large region  51 . In this way, it is possible to enhance a quick drying property of the large region  51  easily touched by the skin of the wearer. In particular, when the large region  51  and the small region  52  of the non-joining portion  50  have spaces therein, a repulsive force is not greatly different between the large region  51  and the small region  52 , and slowly changes. Thus, a tactile property of the top sheet  10  may be softened. 
         [0019]    In the top sheet  10  of the invention, each of the plurality of joining portions  40  preferably has a shape in which a first line portion  41 , a second line portion  42 , and a third line portion  43  connected to one another branch off from a junction  44  thereof in different directions. In addition, the first line portion  41  is preferably curved or bent to swell in a certain direction, and the second line portion  42  is preferably curved or bent to swell in an opposite direction to the first line portion  41 . In other words, a soft S-shape (curved line shape) or Z-shape (bent line shape) is formed by the first line portion  41  and the second line portion  42 . 
         [0020]    As in the above-described configuration, when each of the joining portions  40  has a shape in which three line portions branch off in three directions, and joining portions  40  having such a shape are regularly disposed, the non-joining portion  50  may be formed. In addition, when the first line portion  41  and the second line portion  42  among the three line portions are curved or bent to swell in opposite directions, the large region  51  and the small region  52  may be formed in the above-described non-joining portion  50 . In this way, in the invention, the joining portion  40  preferably has a λ-shape. In addition, in the invention, since all the plurality of joining portions  40  may have the λ-shape, and be disposed in the same direction, an appearance of the top sheet  10  is excellent. 
         [0021]    In the top sheet  10  of the invention, three λ-shaped joining portions  40  are preferably positioned around one certain non-joining portion  50 . In this instance, the three joining portions  40  are a first joining portion  40   a , a second joining portion  40   b , and a third joining portion  40   c.    
         [0022]    In this case, a portion around the one certain non-joining portion  50  is preferably demarcated by elements (i) to (vi) below. 
         [0023]    (i) First line portion  41  and second line portion  42  of first joining portion  40   a    
         [0024]    (ii) Second line portion  42  and third line portion  43  of second joining portion  40   b    
         [0025]    (iii) Third line portion  43  and first line portion  41  of third joining portion  40   c    
         [0026]    (iv) First gap  61  between first line portion  41  of first joining portion  40   a  and third line portion  43  of second joining portion  40   b    
         [0027]    (v) Second gap  62  between second line portion  42  of second joining portion  40   b  and first line portion  41  of third joining portion  40   c    
         [0028]    (vi) Third gap  63  between third line portion  43  of third joining portion  40   c  and second line portion  42  of first joining portion  40   a    
         [0029]    When the portion around the non-joining portion  50  is demarcated as described above, the non-joining portion  50  including the large region  51  and the small region  52  may be appropriately formed. 
         [0030]    In the top sheet  10  of the invention, a height at which the large region  51  swells is preferably higher than a height at which the small region  52  swells. 
         [0031]    As in the above-described configuration, when the convex large region  51  is higher in height than the convex small region  52 , the liquid touching the top sheet  10  may be rapidly moved from the large region  51  to the small region  52 . In addition, when the large region  51  is higher than the small region  52 , the skin of the wearer easily touches the large region  51  having the large area and the high height. On the contrary, the skin of the wearer rarely touches the small region  52  having the small area and the low height. Therefore, the skin of the wearer easily touches the large region  51  having a quick drying property, and is prevented from touching the small region  52  which is difficult to dry. Further, when the small region  52  is lower than the large region  51 , the large region  51  is supported by the small region  52 , and a cushioning property of the large region  51  is enhanced. For this reason, even when a body pressure of the wearer is applied to the top sheet  10 , the large region  51  is rarely crushed. In addition, even when the large region  51  is crushed once, an original shape is easily restored. 
         [0032]    In the top sheet  10  of the invention, the large region  51  may have a space therein, and an inside of the small region  52  may be filled with fiber. 
         [0033]    As in the above-described configuration, when the large region  51  is formed in a dome shape having an internal space, and an inside of the small region  52  is filled with fiber included in the upper layer sheet  11 , the liquid touching the top sheet  10  easily moves from the large region  51  to the small region  52 . In addition, when the large region  51  is supported by the small region  52 , the cushioning property of the large region  51  is enhanced. 
         [0034]    In the top sheet  10  of the invention, the large region  51  and the small region  52  may have spaces therein. 
         [0035]    As in the above-described configuration, in the invention, the non-joining portion  50  surrounded by the plurality of joining portions  40  has a shape including only the large region  51  having the large area and the small region  52  having the small area. In addition, the large region  51  and the small region  52  are formed in a dome shape swelled to hold a space therein. In this way, the liquid touching the top sheet  10  may be rapidly moved from the large region  51  to the small region  52 , and the quick drying property of the large region  51  easily touched by the skin of the wearer may be enhanced. Further, when the large region  51  and the small region  52  of the non-joining portion  50  have spaces therein, a repulsive force is not greatly different between the large region  51  and the small region  52 , and slowly changes. Thus, a tactile property of the top sheet  10  may be softened. 
         [0036]    In the top sheet  10  of the invention, crush points  53  that press the upper layer sheet  11  toward a side of the lower layer sheet  12  are preferably formed in some of the plurality of non-joining portions  50 . In this case, the non-joining portions  50  in which the crush points  53  are formed are preferably continuously disposed in a certain direction. 
         [0037]    As in the above-described configuration, a plurality of joining portions  40  is regularly formed by performing embossing on the top sheet  10 , and a non-joining portion  50  surrounded by the joining portions  40  is convexly swelled to hold a space therein. However, in a pattern in which a plurality of non-joining portions  50  is regularly arranged, crush points  53  are formed in some of the non-joining portions  50  to lower a swelling height, and a space therein is eliminated or narrowed. In other words, a non-joining portion  50  in which a crush point  53  is formed is inhibited from convexly swelling, and is lower in height than another adjacent non-joining portion  50  in which the crush point  53  is not formed. Further, a space is generated between the non-joining portion  50  in which the crush point  53  is formed and the skin of the wearer. In this way, when non-joining portions  50  in which crush points  53  are formed are continuously disposed in a certain direction in a pattern of non-joining portions  50  in which crush points  53  are not formed, a liquid flow path may be formed along the certain direction of connecting the crush points  53 . In addition, when the non-joining portion  50  is pressed, the space inside the non-joining portion  50  is narrowed. Thus, diffusion of the liquid may be induced along the certain direction of connecting the crush points  53  due to a capillary phenomenon. Therefore, for example, when a column of the non-joining portions  50  in which the crush points  53  are formed is formed on an outer side of the top sheet  10  in the width direction, and even when urine is excreted around a side edge of the top sheet  10 , a diffusion direction of urine may be adjusted to a direction in which side leakage does not occur. In this way, side leakage of urine may be prevented by appropriately controlling the diffusion direction of urine using the crush point  53 . 
         [0038]    In the top sheet of the invention, the joining portion  40  is preferably formed between adjacent crush points  53 . Specifically, when a virtual straight line connecting the crush points  53  is drawn, a part of the joining portion  40  is preferably inevitably positioned between adjacent crush points  53  on the straight line. 
         [0039]    As in the above-described configuration, when the joining portion  40  is provided between the crush points  53 , a slightly swelling small wall portion  54  is formed between the crush point  53  and the joining portion  40 . When the small wall portion  54  is formed in this way, a cushioning property of the upper layer sheet  11  may be maintained when compared to a case in which the upper layer sheet  11  is fully crushed without forming the small wall portion  54 . In addition, when the small wall portion  54  is formed, a speed of the liquid flowing along the crush points  53  ranged in one direction may be appropriately decreased. Thus, the liquid may be effectively absorbed around the crush points  53 . In other words, when the joining portion  40  is not provided between the crush points  53 , there is a possibility that a portion between the crush points  53  may be flat or a groove may be formed therebetween. Then, there is a possibility that the liquid may rapidly flow on the crush points  53 , and pass by the crush points  53  without stopping. In this regard, when the small wall portion  54  is provided around the crush point  53  such that the liquid is retained to some extent around the crush point  53  as in the above-described configuration, it is possible to effectively utilize absorption performance of the whole top sheet  10 . 
         [0040]    The top sheet of the invention is preferably divided into a plurality of joining portion forming regions  70  and a plurality of joining portion non-forming regions  80 . The joining portion forming regions  70  are regions in which the joining portion  40  is formed in at least a portion in the width direction. The joining portion non-forming regions  80  are regions in which the joining portion  40  is not formed across the whole width direction between joining portion forming regions  70 . 
         [0041]    Herein, the plurality of joining portion non-forming regions  80  includes at least a first region  81  whose length in the longitudinal direction (vertical width) corresponds to a first length S 1 , and a second region  82  whose length in the longitudinal direction (vertical width) corresponds to a second length S 2 . In addition, the second length S 2  is shorter than the first length S 1 . 
         [0042]    As in the above-described configuration, the joining portion non-forming regions  80  in which the joining portion  40  is not formed across the whole width direction are provided in at least two positions, and vertical widths of the respective joining portion non-forming regions  80  are made different from each other. A joining portion non-forming region  80  having a wide vertical width may smoothly lead urine inside a capillary tube even when the urine is in a state in which salinity concentration and viscosity are high and a movement driving force is small. For this reason, the joining portion non-forming region  80  having the wide vertical width is suitable for diffusion of urine having high salinity concentration. Meanwhile, a joining portion non-forming region  80  having a narrow vertical width may effectively diffuse a liquid in the width direction even when the amount of the liquid is small. Furthermore, the joining portion non-forming region  80  having the narrow vertical width is suitable for diffusion of urine having low salinity concentration. In this way, the top sheet  10  of the invention may appropriately diffuse urine irrespective of whether salinity concentration of urine is high or low. Therefore, the top sheet  10  has a structure that responds to a change in salinity concentration of excreted urine. 
         [0043]    A second aspect of the invention relates to an absorbent article  100  including the top sheet  10 . 
         [0044]    The absorbent article  100  of the invention includes a liquid-permeable top sheet  10 , a liquid-impermeable back sheet  20 , and an absorber  30  positioned therebetween. 
         [0045]    The top sheet  10  is the same as the above-described top sheet according to the first aspect. 
         [0046]    In more detail, the top sheet  10  includes an upper layer sheet  11 , a lower layer sheet  12 , a plurality of joining portions  40  that joins the upper layer sheet  11  and the lower layer sheet  12  to each other, and a plurality of non-joining portions  50  surrounded by the plurality of joining portions  40 . Each of the non-joining portions  50  includes a large region  51  having a relatively large area, and a small region  52  having a relatively small area and extending in one direction from the large region  51 . The upper layer sheet  11  convexly swells in the large region  51  and the small region  52 . 
         [0047]    The large region  51  and the small region  52  may hold spaces therein, and insides thereof may be filled with fiber. 
       Advantageous Effects of Invention 
       [0048]    According to the invention, it is possible to provide a top sheet in which a region easily touching a skin of a wearer has an enhanced quick drying property. The top sheet of the invention maintains a crisp touch for a long time and is excellent in feeling since a region easily touching the skin of the wearer rapidly dries even when the top sheet is touched by a liquid such as urine and damped. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0049]      FIG. 1  is a plan view of an absorbent article viewed from a top sheet side. 
           [0050]      FIG. 2  is an enlarged view of an embossing pattern formed on a top sheet. 
           [0051]      FIG. 3  illustrates components included in the embossing pattern of the top sheet by extracting the components. 
           [0052]      FIG. 4  is an explanatory drawing for a scheme of designing a joining portion formed in the top sheet. 
           [0053]      FIGS. 5( a ) to 5( c )  illustrate cross-sectional views of a top sheet according to a first embodiment. 
           [0054]      FIG. 6  illustrates an example of a method of manufacturing the top sheet according to the first embodiment. 
           [0055]      FIGS. 7( a ) to 7( c )  illustrate cross-sectional views of a top sheet according to a second embodiment. 
           [0056]      FIGS. 8( a ) and 8( b )  illustrate a cross-sectional view of a region in which a crush point is formed. 
           [0057]      FIG. 9  illustrates an example of a method of manufacturing the top sheet according to the second embodiment. 
           [0058]      FIG. 10  illustrates an example of a method of manufacturing the region in which the crush point is formed. 
           [0059]      FIG. 11  is a plan view for description of a concept of a joining portion forming region and a joining portion non-forming region. 
           [0060]      FIG. 12  is an enlarged view of an inside of a dotted frame illustrated in  FIG. 11 . 
           [0061]      FIG. 13  is a cross-sectional view of a region including the joining portion non-forming region. 
           [0062]      FIG. 14  illustrates components included in the embossing pattern of the top sheet by extracting the components. 
           [0063]      FIG. 15  illustrates a first modified example of the embossing pattern. 
           [0064]      FIG. 16  illustrates a second modified example of the embossing pattern. 
           [0065]      FIG. 17  illustrates a third modified example of the embossing pattern. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0066]    Hereinafter, embodiments for implementing the invention will be described using drawings. The invention is not restricted to a mode described below, and includes a mode appropriately corrected from the mode below within a clear range by those skilled in the art. 
         [0067]    In this specification, a “longitudinal direction” basically refers to a direction (Y-axis direction) of connecting a front body part and a rear body part in an absorbent article, and a “width direction” refers to a direction (X-axis direction) two-dimensionally perpendicular to the longitudinal direction. 
         [0068]    In addition, in this specification, “A to B” indicates “A or more and B or less”. 
       1. First Embodiment: When Inside of Small Region is Filled with Fiber 
       [0069]    A description will be given of a first embodiment of a disposable diaper according to the invention with reference to  FIG. 1  to  FIG. 7( c ) . The first embodiment is a mode in which an inside of a small region  52  of an upper layer sheet  11  described below is filled with fiber. 
         [0070]      FIG. 1  is a plan view of an absorbent article  100  according to the first embodiment of the invention viewed from a skin facing surface side. For example, the absorbent article  100  according to the invention may be used for a disposable diaper, a urine pad, a panty liner, a light incontinence pad, and a sanitary napkin.  FIG. 1  schematically illustrates an internal structure of the absorbent article  100 . As illustrated in  FIG. 1 , the absorbent article  100  includes a top sheet  10 , a back sheet  20 , and an absorber  30 . The top sheet  10  is a sheet disposed on a skin facing surface side of the absorber  30  to directly come into contact with a skin of a wearer. In addition, the back sheet  20  is disposed on a non-skin facing surface side of the absorber  30 . As illustrated in  FIG. 1 , the top sheet  10  and the back sheet  20  may be joined to each other around the absorber  30 . In this way, the absorber  30  is enclosed between the top sheet  10  and the back sheet  20 . 
         [0071]    The top sheet  10  is a member that directly comes into contact with a skin of a crotch portion of the wearer to allow a liquid such as urine to permeate the absorber  30 . For this reason, the top sheet  10  is made of a liquid-permeable material having high flexibility. For example, the liquid-permeable material refers to a material through which 5 ml of room temperature water permeates within one minute when the water is placed thereon under standard atmospheric pressure. Examples of the liquid-permeable material included in the top sheet  10  include woven fabric, nonwoven fabric, or a porous film. In addition, for example, a material obtained by performing a hydrophilic treatment on fiber of a thermoplastic resin such as polypropylene, polyethylene, polyester, or nylon, and then forming a nonwoven fabric using the fiber may be used. 
         [0072]    The back sheet  20  is a member for preventing liquid, which permeates the top sheet  10  and is absorbed by the absorber  30 , from leaking to the outside. For this reason, the back sheet  20  is made of a liquid-impermeable material. For example, the liquid-impermeable material refers to a material through which 5 ml of room temperature water does not permeate after one minute or more when the water is placed thereon under standard atmospheric pressure. An example of the liquid-impermeable material contained in the back sheet  20  corresponds to a liquid-impermeable film made of polyethylene resin. In particular, it is preferable to use a microporous polyethylene film in which a plurality of minute holes having a size in a range of 0.1 to 4 μm is formed. 
         [0073]    The absorber  30  is a member for absorbing liquid such as urine, and holding the absorbed liquid. The absorber  30  is disposed between the liquid-permeable top sheet  10  and the liquid-impermeable back sheet  20 . The absorber  30  is made of an absorbent material having a function of absorbing liquid such as urine. A known material may be employed as the absorbent material included in the absorber  30 . For example, one type may be independently used or two or more types may be used in combination as the absorbent material among crush pulp (fluff pulp), a high absorbency polymer, or a hydrophilic sheet. Normally, the absorbent material is used by being formed in a shape of a mat having a single layer or a plurality of layers. 
         [0074]    The absorbent article  100  has a longitudinal direction and a width direction. In the drawings of this application, the longitudinal direction of the absorbent article  100  is indicated by a Y-axis direction, and the width direction of the absorbent article  100  is indicated by an X-axis direction. 
         [0075]    As illustrated in  FIG. 1 , the top sheet  10  is formed by stacking and bonding a plurality of sheet members together. Two or more sheet members may be included in the top sheet  10 . For example, two to five sheet members may be included therein. In the embodiment illustrated in  FIG. 1 , the top sheet  10  is configured by bonding two sheet members corresponding to an upper layer sheet  11  and a lower layer sheet  12  together. The upper layer sheet  11  is positioned on the skin facing surface side, and the lower layer sheet  12  is positioned on the non-skin facing surface. For this reason, a sheet member directly coming into contact with the skin of the wearer corresponds to the upper layer sheet  11 . 
         [0076]    Each of the upper layer sheet  11  and the lower layer sheet  12  may be made of a liquid-permeable material such as woven fabric, nonwoven fabric, a porous film, etc. In particular, nonwoven fabric is preferably used as the upper layer sheet  11  and the lower layer sheet  12 . Nonwoven fabric made of a known fiber may be used. 
         [0077]    Examples of nonwoven fabric may include various nonwoven fabrics such as air-through nonwoven fabric, heat-bond nonwoven fabric, spunbond nonwoven fabric, melt-blown nonwoven fabric, spun lace nonwoven fabric, and needle-punch nonwoven fabric. In addition, when the upper layer sheet  11  and the lower layer sheet  12  are joined to each other using heat fusion, heat-fusible fiber is preferably included in nonwoven fabric. Fiber having a sheath-core structure such as PET/PE, PP/PE, etc. is preferable as heat-fusible fiber. In addition, hydrophilic treatment using a surfactant, etc. is preferably performed on nonwoven fabric. 
         [0078]    As illustrated in  FIG. 1 , the upper layer sheet  11  and the lower layer sheet  12  are joined to each other by embossing. Embossing refers to a processing method of joining two thermoplastic sheet members by interposing the sheet members between an embossing roller provided with convex embossing protrusions having a predetermined pattern on an outer circumferential surface and a plane roller having a flat surface while heating the sheet members. When embossing is performed, a plurality of concave joining portions  40  is formed on the top sheet  10  at positions touched by the embossing protrusions of the embossing roller, and the upper layer sheet  11  and the lower layer sheet  12  are fusion-bonded to each other in the joining portions  40 . In addition, in general, when the upper layer sheet  11  and the lower layer sheet  12  are joined to each other by embossing, the upper layer sheet  11  becomes thinner in the joining portions  40 . For this reason, the upper layer sheet  11  relatively swells in non-joining portions  50  in which the joining portions  40  are not formed. In this way, the top sheet  10  is formed by heat-fusing the plurality of sheet members together using embossing. 
         [0079]    Next, a description will be given of an embossing pattern formed on the top sheet  10 .  FIG. 2  is an enlarged view of the embossing pattern, and illustrates an inside of a dotted frame illustrated in  FIG. 1  by enlarging the inside. In addition,  FIG. 3  is another enlarged view illustrating components included in one non-joining portion  50  in the embossing pattern by extracting the components. 
         [0080]    As illustrated in  FIG. 2  and  FIG. 3 , the embossing pattern of the top sheet  10  includes a plurality of joining portions  40  that joins the upper layer sheet  11  and the lower layer sheet  12  to each other, and a plurality of non-joining portions  50  surrounded by the plurality of joining portions  40 . The plurality of joining portions  40  is regularly disposed at intervals. Specifically, a plurality of joining portions  40  having the same shape, size, and direction is disposed by being arranged in column shapes at certain intervals in the longitudinal direction, and a plurality of columns of the joining portions  40  is formed in the width direction. In addition, in adjacent columns of joining portions  40 , the respective joining portions  40  are differently arranged in the longitudinal direction, and a so-called zigzag arrangement is formed. In addition, the respective joining portions  40  are arranged on straight lines in the longitudinal direction and the width direction. In the joining portions  40 , the upper layer sheet  11  and the lower layer sheet  12  are heat-fused together. For this reason, the upper layer sheet  11  is concavely hollowed in the joining portions  40 . Meanwhile, the non-joining portions  50  correspond to regions surrounded by the plurality of joining portions  40 , and the upper layer sheet  11  and the lower layer sheet  12  are not joined to each other in the regions. For this reason, when compared to the joining portions  40 , the non-joining portions  50  convexly swells in a direction in which the upper layer sheet  11  touches the skin of the wearer. As illustrated in  FIG. 1  to  FIG. 3 , in the top sheet  10  of the invention, the joining portions  40  and the non-joining portions  50  have novel shapes which have not been present in the past. 
         [0081]    As illustrated in  FIG. 2  and  FIG. 3 , a portion of the non-joining portion  50  has a shape extending in a certain direction. For example, the shape of the non-joining portion  50  may be represented by a bulb shape, a keyhole shape, a gourd shape, a pear shape, etc. Specifically, the non-joining portion  50  includes a large region  51  having a relatively large area and a small region  52  having a relatively small area and extending only in one direction from the large region  51 . The large region  51  and the small region  52  have no boundary therebetween, and are integrally connected to each other. In other words, the joining portion  40  is not formed between the large region  51  and the small region  52 . As illustrated in the figure, the large region  51  and the small region  52  have different shapes. In an example illustrated in the figure, the large region  51  corresponds to a region having a substantially perfect circular shape. In addition, the small region  52  corresponds to a remaining region obtained by excluding the perfect circular large region  51  from the non-joining portion  50 . In the example illustrated in the figure, the small region  52  may be regarded as a substantially square region. For this reason, in a preferable mode illustrated in the figure, the non-joining portion  50  assumes a shape obtained by integrally combining the circular large region  51  and the quadrate small region  52  together. 
         [0082]    Areas of the large region  51  and the small region  52  are difficult to be accurately measured. However, as illustrated in  FIG. 3 , when the perfect circular large region  51  is first demarcated, and the rectangular small region  52  is demarcated in a remaining portion within the non-joining portion  50 , and widths (widths in the X-axis direction) thereof are compared, the width of the large region  51  is clearly wider than the width of the small region. Similarly, when the perfect circular large region  51  is first demarcated, and the rectangular small region  52  is demarcated in a remaining portion within the non-joining portion  50 , and lengths (lengths in the Y-axis direction) thereof are compared, the length of the large region  51  is longer than the length of the small region. In this way, the large region  51  having the larger area may be regarded as a region having a larger width and length than those of the small region  52 . Similarly, the small region  52  having the small area may be regarded as a region having a smaller width and length than those of the large region  51 . The width and length of the small region  52  are preferably half (½) or less the width and length of the large region  51 , respectively. 
         [0083]    In addition, as illustrated in  FIG. 2 , the plurality of non-joining portions  50  having substantially the same shapes is regularly formed in the embossing pattern of the top sheet  10 . Further, directions in which small regions  52  extend from large regions  51  are identical to one another in the respective non-joining portions  50 . For this reason, a unified regular pattern is represented on a surface of the top sheet  10 , and the pattern is beautiful in terms of appearance. 
         [0084]    The above-described non-joining portion  50  having a particular shape is formed by a plurality of joining portions  40  having a particular shape. As illustrated in  FIG. 1  to  FIG. 3 , in the invention, the joining portion  40  preferably has a shape in which three line portions  41  to  43  branch off in three different directions. In the example illustrated in  FIG. 1  to  FIG. 3 , each of the joining portions  40  has a shape of “λ”. In addition, the embossing pattern of the top sheet  10  may be formed by the joining portions  40  having the same shape (λ shape). 
         [0085]    A detailed description will be given of a shape and arrangement of the joining portions  40  with reference to  FIG. 3 . As illustrated in  FIG. 3 , the joining portion  40  has a shape in which the first line portion  41 , the second line portion  42 , and the third line portion  43  branch off from a junction  44  thereof in different directions. In other words, proximal ends (one ends) of the first line portion  41 , the second line portion  42 , and the third line portion  43  are connected at the junction  44 , and distal ends (the other ends) of the first line portion  41 , the second line portion  42 , and the third line portion  43  are directed in different directions. In addition, at least the first line portion  41  and the second line portion  42  preferably have a shape curved in a circular arc shape, or a shape bent at one or more turning points. In the example illustrated in  FIG. 3 , the first line portion  41  and the second line portion  42  are curved in circular arc shapes. In addition, as illustrated in  FIG. 3 , in the first line portion  41  and the second line portion  42  having the circular arc shapes, directions in which arcs bulge out (directions in which the arcs warp) preferably correspond to opposite directions. In other words, when the first line portion  41  and the second line portion  42  are connected to each other, a soft S-shape is formed. In addition, the third line portion  43  may have a circular arc shape similarly to the first line portion  41  and the second line portion  42 , or have a linear shape. In addition, directions in which the first line portion  41  and the second line portion  42  extend are preferably substantially orthogonal to a direction in which the third line portion  43  extends. For example, in the example illustrated in  FIG. 1  to  FIG. 3 , while the first line portion  41  and the second line portion  42  substantially extend in the longitudinal direction (Y-axis direction), the third line portion  43  substantially extends in the width direction (X-axis direction). The directions in which the first line portion  41  and the second line portion  42  extend substantially correspond to opposite directions. For example, while the first line portion  41  extends in a positive direction on a Y axis (upward in the figure), the second line portion  42  extends in a negative direction on the Y axis (downward in the figure). In this sense, the directions in which the first line portion  41  and the second line portion  42  extend are substantially orthogonal to the direction in which the third line portion  43  extends. The first line portion  41  and the second line portion  42  may extend in the width direction (X-axis direction), and the third line portion  43  may extend in the longitudinal direction (Y-axis direction). 
         [0086]    In addition, as illustrated in  FIG. 3 , the first line portion  41 , the second line portion  42 , and the third line portion  43  may have different lengths. In the example illustrated in  FIG. 3 , the first line portion  41  is longer than the second line portion  42 , and the second line portion  42  is longer than the third line portion  43  (the first line portion  41 &gt;the second line portion  42 &gt;the third line portion  43 ). In addition, when all the respective line portions  41  to  43  are formed in circular arc shapes, curvatures (or radii of curvatures) of the respective line portions  41  to  43  may be different from one another or identical to one another. In the example illustrated in the figure, all the curvatures of the respective line portions  41  to  43  correspond to the same value. 
         [0087]    As illustrated in  FIG. 3 , three joining portions  40  are positioned around one certain non-joining portion  50 . The three joining portions  40  positioned around the one certain non-joining portion  50  are defined as a first joining portion  40   a , a second joining portion  40   b , and a third joining portion  40   c . In this case, a portion around the one certain non-joining portion  50  is demarcated by elements (i) to (vi) below. 
         [0088]    (i) First line portion  41  and second line portion  42  of first joining portion  40   a    
         [0089]    (ii) Second line portion  42  and third line portion  43  of second joining portion  40   b    
         [0090]    (iii) Third line portion  43  and first line portion  41  of third joining portion  40   c    
         [0091]    (iv) First gap  61  between first line portion  41  of first joining portion  40   a  and third line portion  43  of second joining portion  40   b    
         [0092]    (v) Second gap  62  between second line portion  42  of second joining portion  40   b  and first line portion  41  of third joining portion  40   c    
         [0093]    (vi) Third gap  63  between third line portion  43  of third joining portion  40   c  and second line portion  42  of first joining portion  40   a    
         [0094]    In other words, as illustrated in  FIG. 3 , firstly, the joining portions  40  are formed such that a distal end of the first line portion  41  of the first joining portion  40   a  and a distal end of the third line portion  43  of the second joining portion  40   b  butt to each other (approach each other). In this instance, the first gap  61  is formed. In addition, the joining portions  40  are formed such that a distal end of the second line portion  42  of the second joining portion  40   b  and a distal end of the first line portion  41  of the third joining portion  40   c  butt to each other (approach each other). In this instance, the second gap  62  is formed. Further, the joining portions  40  are formed such that a distal end of the third line portion  43  of the third joining portion  40   c  and a distal end of the second line portion  42  of the first joining portion  40   a  butt to each other (approach each other). In this instance, the third gap  63  is formed. The first gap  61 , the second gap  62 , and the third gap  63  may correspond to a distance in a range of about 0.1 mm to 20 mm. According to such a principle, a plurality of joining portions  40  is disposed, and a regular embossing pattern is formed. 
         [0095]    As illustrated in  FIG. 3 , the circular large region  51  and the quadrate small region  52  are formed in the non-joining portion  50 , a portion around which is demarcated by the above elements (i) to (vi). The portion around the circular large region  51  is demarcated by the first line portion  41  of the first joining portion  40   a , the second line portion  42 /the third line portion  43  of the second joining portion  40   b , the first gap  61 , and the second gap  62 . Herein, the first line portion  41  of the first joining portion  40   a  and the second line portion  42 /the third line portion  43  of the second joining portion  40   b  are curved to bulge out toward an outside of the non-joining portion  50  (the large region  51 ). For this reason, the large region  51  has a substantially circular shape, and the area thereof becomes larger. Meanwhile, a portion around the quadrate small region  52  is demarcated by the second line portion  42  of the first joining portion  40   a , the first line portion  41 /the third line portion  43  of the third joining portion  40   c , and the third gap  63 . Herein, the second line portion  42  of the first joining portion  40   a  and the first line portion  41 /the third line portion  43  of the third joining portion  40   c  are curved to bulge out toward an inside of the non-joining portion  50  (the small region  52 ). For this reason, the area of the small region  52  becomes smaller. 
         [0096]    In addition, as illustrated in  FIG. 2  and  FIG. 3 , it is considered that each of the plurality of non-joining portions  50  corresponds to an independent region divided by the joining portions  40 , and is not connected to another non-joining portion  50 . However, in the strict sense, it can be understood that non-joining portions  50  are connected to each other through the gaps  61  to  63 . However, since the gaps  61  to  63  correspond to a region formed when distal ends of line portions of three joining portions  40  butt to one another as illustrated in  FIG. 3 , the gaps  61  to  63  are concavely hollowed at a similar level to that of the joining portion  40  when the upper layer sheet  11  and the lower layer sheet  12  are actually joined to each other. At least the gaps  61  to  63  do not convexly swell. Specifically, each of the gaps  61  to  63  positioned around the one certain non-joining portion  50  corresponds to a region in which the first line portion  41 , the second line portion  42 , and the third line portion  43  of three joining portions  40  butt to one another. For this reason, as a result of forming the three joining portions  40 , the gaps  61  to  63  crush together with the three joining portions  40  or are inhibited from swelling. Therefore, adjacent convex non-joining portions  50  are not connected to each other through the gaps  61  to  63 , and the respective convex non-joining portions  50  are substantially independent of each other. In addition, as illustrated in  FIG. 2  and  FIG. 3 , the third line portion  43  of each of the joining portions  40  separates non-joining portions  50  adjacent to each other in the longitudinal direction (Y direction) such that the non-joining portions  50  are not connected to each other. In this regard, the third line portion  43  of each of the joining portions  40  has significance. 
         [0097]    Next, a description will be given of an example of a method of designing the embossing pattern with reference to  FIG. 4 . As illustrated in  FIG. 4 , first, a latticed pattern is presumed in which a plurality of virtual perfect circles having a certain amount of width is disposed to come into contact with one another such that width portions thereof overlap each other. In other words, the latticed pattern refers to a pattern in which a certain virtual perfect circle is disposed to come into contact with other virtual perfect circles at an interval of 90 degrees. All the plurality of virtual perfect circles is formed to have the same radius (r). The radius (r) of the virtual circle is preferably in a range of 1.0 mm to 11.0 mm, and more preferably in a range of 2.0 mm to 5.0 mm. A width of the virtual perfect circle is identical to a width of the joining portion  40 . 
         [0098]    In this case, firstly, the first line portion  41  of the joining portion  40  is formed in a circular arc shape curved along a circumference of a certain virtual perfect circle. A length L 1  of the first line portion  41  is obtained using [Equation] L 1 =2πr×(θ 1 /360). Herein, “r” denotes a radius of the virtual perfect circle. In addition, when each of the distal end and the proximal end of the first line portion  41  is connected to a center of the virtual perfect circle by straight lines, “θ 1 ” denotes an angle formed by the respective straight lines (that is, an angle of a sector). For example, θ 1  may be set to a range of 60 degrees to 100 degrees, 70 degrees to 90 degrees, or 75 degrees to 85 degrees. 
         [0099]    In addition, the second line portion  42  and the third line portion  43  of the joining portion  40  are formed along a circumference of a different virtual perfect circle from that of the first line portion  41  described above. That is, the second line portion  42  and the third line portion  43  are positioned on a circumference of a virtual perfect circle adjacent to the virtual perfect circle on which the first line portion  41  is formed. For this reason, the junction  44  of the respective line portions  41  to  43  is positioned on a boundary between two adjacent virtual perfect circles. In addition, the second line portion  42  and the third line portion  43  are positioned on a circumference of the same virtual perfect circle. Therefore, the second line portion  42  and the third line portion  43  integrally form one circular arc shape. For this reason, it may be considered that each of the joining portions  40  has a shape obtained by combining two circular arcs corresponding to a circular arc formed by the first line portion  41  and a circular arc formed by the second line portion  42  and the third line portion  43 . 
         [0100]    A length L 2  of the second line portion  42  is obtained using [Equation] L 2 =2πr×(θ 2 /360). When each of the distal end and the proximal end of the second line portion  42  is connected to a center of the virtual perfect circle by straight lines, “θ 2 ” denotes an angle formed by the respective straight lines (that is, an angle of a sector). For example, θ 2  may be set to a range of 45 degrees to 85 degrees, 50 degrees to 80 degrees, or 55 degrees to 70 degrees. In addition, a length L 3  of the third line portion  43  is obtained using [Equation] L 3 =2πr×(θ 3 /360). When each of the distal end and the proximal end of the third line portion  43  is connected to a center of the virtual perfect circle by straight lines, “θ 3 ” denotes an angle formed by the respective straight lines (that is, an angle of a sector). For example, θ 2  may be set to a range of 5 degrees to 45 degrees, 10 degrees to 40 degrees, or 20 degrees to 35 degrees. In addition, as illustrated in  FIG. 4 , a sum of θ 2  and θ 3  is preferably 90 degrees (±5 degrees). 
         [0101]    In this way, it is possible to relatively easily design the joining portions  40  having the particular shape. In addition, the respective joining portions  40  are disposed based on a pattern of virtual perfect circles disposed in a lattice shape, and thus the respective joining portions  40  may be regularly disposed. The distal ends of the respective line portions  41  and  43  are preferably formed as smooth curves through rounding. In addition, an acute angle is formed at a connection position of the first line portion  41  and the third line portion  43 , and thus the connection position is preferably subjected to rounding to form a curve. 
         [0102]      FIGS. 5( a ) to 5( c )  schematically illustrate cross sections of the top sheet  10 .  FIG. 5( b )  is a cross-section view taken along Y-Y line illustrated in  FIG. 5( a ) , and  FIG. 5( c )  is a cross-section view taken along X-X line illustrated in  FIG. 5( a ) . As illustrated in  FIG. 5( b )  and  FIG. 5( c ) , each of the non-joining portions  50  surrounded by a plurality of joining portions  40  includes one large region  51  and one small region  52 . In addition, the upper layer sheet  11  convexly swells in the large region  51  and the small region  52 . Further, a height at which the upper layer sheet  11  swells in the large region  51  is higher than a height at which the upper layer sheet  11  swells in the small region  52 . For example, when a height H 1  of the small region  52  is set to 100%, a height H 2  of the large region  51  is preferably in a range of 120% to 300%, 130% to 250%, or 140% to 200%. 
         [0103]    In addition, in an example illustrated in  FIG. 5( b )  and  FIG. 5( c ) , the large region  51  of the non-joining portion  50  is formed in a dome shape that holds a space on the inside. In other words, the upper layer sheet  11  is separated from the lower layer sheet  12  and convexly swells in the large region  51 . For this reason, a space is formed between the upper layer sheet  11  and the lower layer sheet  12 . Meanwhile, an inside of the small region  52  of the non-joining portion  50  is filled with fiber included in the upper layer sheet  11 . For this reason, in the small region  52 , fiber of the upper layer sheet  11  at least partially comes into contact with the lower layer sheet  12 . In this way, a density of fiber included in the upper layer sheet  11  may be low in the large region  51  and high in the small region  52 . 
         [0104]    In order to form the large region  51  in the dome shape, the upper layer sheet  11  may be pressed from the non-skin facing surface side (rear surface side) to convexly swell the upper layer sheet  11  in a region corresponding to the large region  51  before the upper layer sheet  11  and the lower layer sheet  12  are overlapped with each other. Thereafter, when the upper layer sheet  11  and the lower layer sheet  12  are overlapped with each other to join both sheets in the respective joining portions  40 , a space is formed between the upper layer sheet  11  and the lower layer sheet  12  in the large region  51 . In addition, when the upper layer sheet  11  is pressed in the region corresponding to the large region  51 , fiber included in the upper layer sheet  11  may be allowed to flow from the large region  51  to the small region  52 . In this way, a fiber density of the large region  51  may be decreased, and a fiber density of the small region  52  may be increased. In this way, it is possible to form the large region  51  which is high in height and low in fiber density, and the small region  52  which is low in height and high in fiber density. 
         [0105]    As described in the foregoing, when a liquid touches the top sheet  10  at the time of urination of the wearer, etc., the liquid may be rapidly moved from the large region  51  to the small region  52  by adjusting the heights and the fiber densities of the large region  51  and the small region  52 . That is, the liquid flows down from the large region  51  high in height to the small region  52  low in height. In addition, the liquid is absorbed by the small region  52  high in fiber density rather than the large region  51  low in fiber density. For this reason, even when the sheet is damp due to the liquid touching the sheet, the large region  51  rapidly dries. The large region  51  has a large area and a high height, and thus easily touches the skin of the wearer. Therefore, when a drying time of the large region  51  is shortened, it is possible to shorten a time at which the liquid touches the skin of the wearer, and to prevent the wearer from feeling an unpleasant feeling. Meanwhile, the liquid moved from the large region  51  is temporarily retained in the small region  52 . For this reason, the small region  52  takes a longer time to fully dry when compared to the large region  51 . However, the small region  52  has a small area and a low height, and thus rarely touches the skin of the wearer. For this reason, even when the small region  52  takes time to dry, the wearer may rarely feel an unpleasant feeling. In addition, in the top sheet  10  of the invention, the small region  52  is provided at only one location for one large region  51 . For this reason, a liquid coming into contact with the large region  51  moves only in one direction toward the small region  52  protruding from the large region  51 . In other words, in the top sheet  10  of the invention, the liquid does not diffuse in every direction around the large region  51 , and thus the number of regions in which the liquid is temporarily retained does not excessively increase. When a plurality of (two or more) regions in which the liquid is retained is present around the large region  51 , there is a demerit that the skin of the wearer is more likely to touch the liquid retaining regions. In addition, there is a concern that the number of liquid retaining regions touched by the skin of the wearer may increase. For this reason, the wearer may feel an unpleasant feeling. On the other hand, when the small region  52  for retaining the liquid is provided at only one location for one large region  51  as in the invention, the number of liquid retaining regions may be suppressed to the minimum. Therefore, according to the invention, a temporary liquid retaining region may be appropriately controlled not to give an unpleasant feeling to the wearer. 
         [0106]    Next, a description will be given of a method of manufacturing the top sheet  10  described above with reference to  FIG. 6 .  FIG. 6  illustrates a method of forming a convex swelling portion on the upper layer sheet  11  in the upper layer sheet  11  and the lower layer sheet  12  included in the top sheet  10 , and then joining the upper layer sheet  11  and the lower layer sheet  12  to each other in a predetermined embossing pattern. As illustrated in  FIG. 6 , an apparatus for manufacturing the top sheet  10  includes a pin roller  110 , an embossing roller  120 , and a plane roller  130 . 
         [0107]    As illustrated in  FIG. 6 , the pin roller  110  has a projection portion  111  that convexly projects at a plurality of locations on a peripheral surface thereof. The projection portion  111  of the pin roller  110  is provided to form the large region  51  that convexly swells on the upper layer sheet  11  of the top sheet  10 . For this reason, the projection portion  111  is provided at a position that comes into contact with a region scheduled to become the large region  51  of the upper layer sheet  11 . 
         [0108]    A plurality of convex embossing protrusions  122  disposed in a predetermined pattern and a plurality of concave hollow portions  123  are formed on a peripheral surface of the embossing roller  120 . The embossing protrusions  122  are provided to join the upper layer sheet  11  and the lower layer sheet  12  of the top sheet  10  in a predetermined embossing pattern. The embossing protrusions  122  of the embossing roller  120  may be heated by a heating device (not illustrated). In addition, the hollow portions  123  are provided at positions corresponding to a plurality of projection portions  111  provided on the peripheral surface of the pin roller  110 , and have shapes capable of receiving the projection portions  111 . The embossing protrusions  122  of the embossing roller  120  are not formed at positions at which the hollow portions  123  are provided. 
         [0109]    A peripheral surface of the plane roller  130  corresponds to a smooth surface. The plane roller  130  is provided to interpose the upper layer sheet  11  and the lower layer sheet  12  of the top sheet  10  between the embossing protrusions  122  of the embossing roller  120  and the plane roller  130  to press and heat the sheets, thereby heat-fusing both sheets. The peripheral surface of the plane roller  130  may be made of metal or rubber. In addition, the peripheral surface of the plane roller  130  may be heated by the heating device (not illustrated). 
         [0110]    As illustrated in  FIG. 6 , the pin roller  110  and the embossing roller  120  are disposed to face each other, and the upper layer sheet  11  is introduced between both rollers. In addition, the embossing roller  120  and the plane roller  130  are disposed to face each other, and the upper layer sheet  11  and the lower layer sheet  12  are introduced in an overlapping state between both rollers. 
         [0111]    As illustrated in  FIG. 6 , the upper layer sheet  11  drawn from an original fabric roll (not illustrated) is introduced between the pin roller  110  and the embossing roller  120  via one or a plurality of guide rollers. Referring to the upper layer sheet  11 , the non-skin facing surface (surface not directly coming into contact with the skin of the wearer) comes into contact with the pin roller  110 , and the skin facing surface (surface directly coming into contact with the skin of the wearer) comes into contact with the embossing roller  120 . In this instance, when the upper layer sheet  11  is fit to the hollow portions  123  of the embossing roller  120  while being pressed against the projection portions  111  of the pin roller  110 , pressed portions swell. In this way, a portion swelling in a dome shape toward the skin facing surface side (the large region  51  of the non-joining portion  50 ) is formed on the upper layer sheet  11 . Thereafter, the upper layer sheet  11  is introduced between the embossing roller  120  and the plane roller  130  while coming into contact with the peripheral surface of the embossing roller  120 . 
         [0112]    Meanwhile, the lower layer sheet  12  drawn from another original fabric roll (not illustrated) is introduced between the embossing roller  120  and the plane roller  130  via one or a plurality of guide rollers. The upper layer sheet  11  and the lower layer sheet  12  overlap each other between the embossing roller  120  and the plane roller  130 . In this instance, the skin facing surface side of the upper layer sheet  11  comes into contact with the embossing roller  120 , and the non-skin facing surface side of the lower layer sheet  12  comes into contact with the plane roller  130 . The upper layer sheet  11  and the lower layer sheet  12  are interposed between the embossing roller  120  and the plane roller  130  in a stacked state, and heat-fused by being heated and pressed. The upper layer sheet  11  and the lower layer sheet  12  are heat-fused according to the embossing pattern of the plurality of embossing protrusions  122  formed on the peripheral surface of the embossing roller  120 . In this way, a plurality of concave joining portions  40  hollowed toward the non-skin facing surface side is formed on the top sheet  10 . In the upper layer sheet  11  and the lower layer sheet  12 , regions coming into contact with the embossing protrusions  122  of the embossing roller  120  correspond to the joining portions  40 , and a region surrounded by a plurality of joining portions  40  corresponds to the non-joining portion  50 . 
         [0113]    In this way, when the upper layer sheet  11  is pressed by the pin roller  110 , and then the upper layer sheet  11  and the lower layer sheet  12  are joined by the embossing roller  120 , the large region  51  of the non-joining portion  50  may be formed in a dome shape that holds a space therein. In addition, when the upper layer sheet  11  is pressed by the projection portions  111  of the pin roller  110 , fiber included in the upper layer sheet  11  may be allowed to flow from the large region  51  to the small region  52  of the non-joining portion  50 . For this reason, it is possible to decrease the fiber density of the large region  51 , and improve the fiber density of the small region  52  at the same time. 
       2. Second Embodiment: When Small Region Holds Space Therein 
       [0114]    Next, a description will be given of a second embodiment of the disposable diaper according to the invention with reference to  FIG. 8( a )  to  FIG. 10 . The second embodiment corresponds to a mode in which the small region  52  of the upper layer sheet  11  holds a space therein. In description of the second embodiment, a similar configuration to that of the above-described first embodiment will not be described, and a difference from the first embodiment will be described in detail. 
         [0115]      FIGS. 7( a ) to 7( c )  illustrate cross-sectional views of a top sheet according to the second embodiment, and correspond to  FIGS. 5( a ) to 5( c ) .  FIG. 7( b )  is a cross-section view taken along Y-Y line illustrated in  FIG. 7( a ) , and  FIG. 7( c )  is a cross-section view taken along X-X line illustrated in  FIG. 7( a ) . As illustrated in  FIGS. 7( b ) and 7( c ) , the large region  51  and the small region  52  of the non-joining portion  50  are formed in dome shapes that hold spaces therein. In other words, the upper layer sheet  11  is separated from the lower layer sheet  12  to convexly swell in the large region  51  and the small region  52 . For this reason, the spaces are formed between the upper layer sheet  11  and the lower layer sheet  12 . These spaces are not filled with fiber included in the upper layer sheet  11  or the lower layer sheet  12 . 
         [0116]    In order to form the large region  51  and the small region  52  in the dome shapes, the upper layer sheet  11  may be pressed from the non-skin facing surface side (rear surface side) to convexly swell the upper layer sheet  11  in regions corresponding to the large region  51  and the small region  52  before the upper layer sheet  11  and the lower layer sheet  12  are overlapped with each other. Alternatively, the upper layer sheet  11  may be sucked from the skin facing surface side (front surface side) to convexly swell the upper layer sheet  11  in the regions corresponding to the large region  51  and the small region  52 . In addition, thereafter, when the upper layer sheet  11  and the lower layer sheet  12  are overlapped with each other to join both sheets in the respective joining portions  40 , spaces are formed between the upper layer sheet  11  and the lower layer sheet  12  in the large region  51  and the small region  52 . In this way, as illustrated in  FIGS. 7( a ) to 7( c ) , the upper layer sheet  11  may be separated from the lower layer sheet  12  to form a state in which spaces are held inside the large region  51  and the small region  52 . In addition, in the present embodiment, the large region  51  swells higher than the small region  52 . Accordingly, the space formed in the large region  51  is wider than the space formed in the small region  52 . For example, when the large region  51  and the small region  52  are formed, adjustment may be performed such that the large region  51  is largely swelled, and the small region  52  is slightly swelled by adjusting a height at which the upper layer sheet  11  is pressed from the non-skin facing surface side. Alternatively, the large region  51  may be largely swelled, and the small region  52  may be slightly swelled by adjusting a suction force for sucking the upper layer sheet  11  from the skin facing surface side. 
         [0117]    When the heights of the large region  51  and the small region  52  are different from each other, and the spaces are formed inside both regions as described above, and when a liquid comes into contact with the top sheet  10 , the liquid may be rapidly moved from the large region  51  to the small region  52 . In other words, the liquid flows down from the large region  51  high in height to the small region  52  low in height. In addition, the liquid is attracted to the small region  52  having a narrow space rather than the large region  51  having a wide space. For this reason, even when the sheet is damp by touching the liquid, an apex of the large region  51  rapidly dries. The large region  51  has a large area and a high height, and thus is easily touched by the skin of the wearer. Therefore, when a drying time at the apex of the large region  51  is shortened, it is possible to shorten a time at which the liquid touches the skin of the wearer, and to prevent the wearer from feeling an unpleasant feeling. Meanwhile, the liquid moved from the large region  51  is temporarily retained in the small region  52 . For this reason, the small region  52  may take a longer time to fully dry when compared to the large region  51 . However, the small region  52  has a small area and a low height, and thus rarely touched by the skin of the wearer. For this reason, even when the small region  52  takes time to dry, the wearer may rarely feel an unpleasant feeling. In addition, when the space is formed in the small region  52 , a drying time of the small region  52  may be shortened. 
         [0118]    In addition, as illustrated in  FIGS. 7( a ) to 7( c ) , when each of the large region  51  and the small region  52  have the dome shapes that hold the spaces, repulsive forces of the large region  51  and the small region  52  with respect to pressing may correspond to the same level. In more detail, when the spaces are formed in both the large region  51  and the small region  52 , and the repulsive forces of both regions are set to the same level or maintained at moderately different levels as in the present embodiment, a touch of the whole top sheet  10  may become softer. 
         [0119]      FIG. 8( a )  is an enlarged view of the embossing pattern, and illustrates an inside of a dotted frame indicated by a symbol A 2  in  FIG. 1  by enlarging the inside. As illustrated in  FIG. 1 ,  FIG. 8( a )  illustrates an outer region of the top sheet  10  in the width direction by enlarging the region. In addition,  FIG. 8( b )  is a cross-sectional view taken along B-B line illustrated in  FIG. 8( a ) . Herein, a description will be given of an example of a case in which a crush point  53  is formed in the top sheet with reference to  FIGS. 8( a ) and 8( b ) . 
         [0120]    In the example illustrated in  FIGS. 8( a ) and 8( b ) , a plurality of convex non-joining portions  50  is formed by performing embossing on the top sheet, crush points  53  are formed in some of the non-joining portions  50 , and the non-joining portions  50  in which the crush points  53  are formed are arranged in a certain direction. In this way, a flow path for a liquid is formed along the certain direction in which the crush points  53  are connected to each other. In addition, when a protrusion of the non-joining portion  50  is pressed, the space inside the non-joining portion is narrowed. Thus, a diffusion of the liquid may be induced along the certain direction in which the crush points  53  are formed due to a capillary phenomenon. Therefore, it is possible to control a diffusion direction of the liquid flowing on the surface of the top sheet. 
         [0121]    As illustrated in  FIG. 8( a ) , the plurality of crush points  53  is formed in the outer region of the top sheet  10  in the width direction. The crush points  53  are formed in some of the plurality of non-joining portions  50  formed on the top sheet  10 . Specifically, the crush point  53  is formed in the large region  51  of the non-joining portion  50 . As illustrated in  FIG. 8( b ) , the crush point  53  is formed by pressing the large region  51  of the non-joining portion  50  in a thickness direction. For this reason, a swelling height of the large region  51  in which the crush point  53  is formed lower. At the same time, the space inside the large region  51  narrows or disappears. The crush point  53  may be formed only by pressing the upper layer sheet  11  or formed by joining the upper layer sheet  11  and the lower layer sheet  12  together in the large region  51 . At least, at the crush point  53 , the upper layer sheet  11  and the lower layer sheet  12  preferably touch each other. In particular, the upper layer sheet  11  and the lower layer sheet  12  are preferably joined together at the crush point  53  in order to maintain the crush point  53 . The upper layer sheet  11  and the lower layer sheet  12  may be heat-fused by heat sealing, ultrasonic sealing, etc. 
         [0122]    In addition, as illustrated in  FIG. 8( a ) , the non-joining portions  50  in which the crush points  53  are formed are continuously formed along the certain direction. In other words, the non-joining portions  50  in which the crush points  53  are formed are adjacent to each other in the certain direction. In the present embodiment, a direction in which the non-joining portions  50  in which the crush points  53  are formed are continued is a direction other than the longitudinal direction (Y-axis direction) and the width direction (X-axis direction) of the absorbent article. Specifically, the direction is a direction inclined at a predetermined angle with respect to the longitudinal direction and the width direction. For example, as illustrated in  FIG. 8( a ) , when the continuously formed crush points  53  are connected by a virtual straight line, an angle (θ) at which the straight line is inclined with respect to the longitudinal direction (Y-axis direction) may be set to 15 degrees to 75 degrees, 30 degrees to 60 degrees, 40 degrees to 50 degrees, or 45 degrees. 
         [0123]    As illustrated in  FIG. 8( a ) , the non-joining portions  50  in which the crush points  53  are formed are disposed in a pattern of non-joining portions  50  in which the crush point  53  is not formed. In other words, at least two non-joining portions  50  in which the crush point  53  is not formed are present around a non-joining portion  50  in which the crush point  53  is formed. Specifically, in the embossing pattern illustrated in  FIG. 8( a ) , six non-joining portions  50  are present around one non-joining portion  50  by being adjacent thereto. Herein, in observation around the non-joining portion  50  in which the crush point  53  is formed, one or two non-joining portions  50  in which crush points  53  are formed are present around the non-joining portion  50 , and the crush point  53  is not formed in five or four remaining non-joining portions  50 . In this way, at least two non-joining portions  50  in which the crush point  53  is not formed are preferably present around the non-joining portion  50  in which the crush point  53  is formed by being adjacent thereto. 
         [0124]    In this way, when the crush points  53  are formed in some of the convexly swelling non-joining portions  50 , and the non-joining portions  50  in which the crush points  53  are formed are continuously disposed along one direction, a liquid flow path may be formed along a direction in which the crush points  53  are continued. In addition, when the non-joining portion  50  is pressed, the space inside the non-joining portion  50  is narrowed. Thus, the liquid is induced along the certain direction in which the crush points  53  are connected due to the capillary phenomenon. In this way, the liquid such as urine may be guided along the direction in which the crush points  53  are continued. Therefore, when a column of the non-joining portions  50  in which the crush points  53  are formed is formed on an outer side of the top sheet  10  in the width direction, and even when urine is excreted around a side edge of the top sheet  10 , a diffusion direction of urine may be adjusted to a direction in which side leakage does not occur. In this way, side leakage of urine may be prevented by appropriately controlling the diffusion direction of urine using the crush point  53 . 
         [0125]    In addition, as illustrated in  FIG. 8( b ) , the joining portion  40  is preferably formed between adjacent crush points  53 . Specifically, when a virtual straight line connecting the crush points  53  is drawn, a part of the joining portion  40  is inevitably positioned between crush points  53  on the straight line. A region in which the joining portion  40  is not formed is not present between the adjacent crush points  53 . For this reason, in a cross-sectional view taken along the straight line that connects the crush points  53 , the crush points  53  and the joining portions  40  are alternately formed as illustrated in  FIG. 8( b ) . In this case, a small wall portion  54  in which the upper layer sheet  11  slightly swells is formed between the crush point  53  and the joining portion  40 . A space may be held inside the small wall portion  54 . A swelling height (H 3 ) of the small wall portion  54  is lower than a swelling height (H 2 ) of the large region  51  of the non-joining portion  50  in which the crush point  53  is not formed. For example, the swelling height (H 3 ) of the small wall portion  54  is preferably in a range of 20% to 80% and particularly preferably in a range of 30% to 70% with respect to the swelling height (H 2 ) of the normal large region  51 . 
         [0126]    When the small wall portion  54  is formed in this way, a cushioning property of the upper layer sheet  11  may be maintained when compared to a case in which the upper layer sheet  11  is fully crushed without forming the small wall portion  54 . In addition, when the small wall portion  54  is formed, a speed of the liquid flowing along the crush points  53  ranged in one direction may be decreased. Thus, the liquid may be effectively absorbed around the crush points  53 . In other words, when the joining portion  40  is not provided between the crush points  53 , there is a possibility that a portion between the crush points  53  may be flat or a groove may be formed therebetween. Then, there is a possibility that the liquid may rapidly flow on the crush points  53 , and pass by the crush points  53  without stopping. In this regard, the small wall portion  54  is preferably provided around the crush point  53  as described above such that the liquid is retained to some extent around the crush point  53 , thereby effectively utilizing absorption performance of the whole top sheet  10 . 
         [0127]    In addition, in  FIG. 8( a ) , a direction in which the liquid flows is indicated by a dotted line arrow. Here, the liquid flows along the direction in which the non-joining portions  50 , in which the crush points  53  are formed, are continued. As indicated by this arrow, it is considered that the liquid flows to pass through the first gap  61  and the second gap  62  between the joining portions  40  (see  FIG. 3 ). A direction in which the first gap  61  is connected to the second gap  62  is parallel to the direction in which the non-joining portions  50 , in which the crush points  53  are formed, are continued. Thus, the liquid may be appropriately diffused by passing through the first gap  61  and the second gap  62 . 
         [0128]    As illustrated in  FIG. 8( a ) , the number of crush points  53  continuously formed along the one direction may be appropriately adjusted. For example, the number of continuous crush points  53  is preferably three or more, and may be set to a range of 3 to 15 or 5 to 10. 
         [0129]    The crush point  53  illustrated in  FIGS. 8( a ) and 8( b )  may be formed in the top sheet according to the first embodiment in addition to the top sheet according to the second embodiment. 
         [0130]    Next, a description will be given of a method of manufacturing the top sheet  10  illustrated in  FIGS. 7( a ) to 7( c )  and  FIGS. 8( a ) and 8( b )  with reference to  FIG. 9  and  FIG. 10 .  FIG. 9  and  FIG. 10  illustrate a method of forming a convex swelling portion on the upper layer sheet  11  in the upper layer sheet  11  and the lower layer sheet  12  included in the top sheet  10 , and then joining the upper layer sheet  11  and the lower layer sheet  12  to each other in a predetermined embossing pattern. As illustrated in  FIG. 9  and  FIG. 10 , an apparatus for manufacturing the top sheet  10  includes a pin roller  110 , an embossing roller  120 , and a plane roller  130 . However,  FIG. 9  illustrates a cross-sectional structure of a portion in which the non-joining portion  50  not having the crush point  53  is formed in the pin roller  110 , the embossing roller  120 , and the plane roller  130 . Meanwhile,  FIG. 10  illustrates a cross-sectional structure of a portion in which the non-joining portion  50  having the crush point  53  is formed in the pin roller  110 , the embossing roller  120 , and the plane roller  130 . 
         [0131]    Firstly, as illustrated in  FIG. 9 , the pin roller  110  has a convexly projecting projection portion  112  at a plurality of locations on a flat surface  111  included in a peripheral surface thereof. The projection portion  112  of the pin roller  110  is provided mainly to form the convexly swelling large region  51  on the upper layer sheet  11  of the top sheet  10 . For this reason, the projection portion  112  is provided at a position that comes into contact with a region scheduled to become the large region  51  of the upper layer sheet  11 . 
         [0132]    The embossing roller  120  includes a flat hill portion  121  included in a peripheral surface thereof, a plurality of convex embossing protrusions  122  disposed in a predetermined pattern on the hill portion  121 , and a plurality of concave hollow portions  123  positioned between hill portions  121 . The embossing protrusions  122  are provided to join the upper layer sheet  11  and the lower layer sheet  12  of the top sheet  10  to each other in a predetermined embossing pattern. The embossing protrusions  122  of the embossing roller  120  may be heated by a heating device (not illustrated). In addition, the hollow portions  123  are provided at positions corresponding to the plurality of projection portions  112  provided on the peripheral surface of the pin roller  110 , and have shapes capable of receiving the projection portions  112 . For this reason, the hollow portions  123  of the embossing roller  120  form the convexly swelling large regions  51  on the upper layer sheet  11  by cooperating with the projection portions  112  of the pin roller  110 . The embossing protrusions  122  of the embossing roller  120  are not formed at positions at which the hollow portions  123  are provided. 
         [0133]    In addition, as illustrated in  FIG. 9 , the hill portion  121  is provided between two hollow portions  123  in a rotation direction of the embossing roller  120 . In this instance, in the present embodiment, an embossing protrusion  122  is formed at a position close to a hollow portion  123  at a front side of the hill portion  121  in the rotation direction. In other words, the embossing protrusion  122  is formed at a position close to the hollow portion  123  at the front side in the rotation direction in the hollow portion  123  at the front side in the rotation direction and a hollow portion  123  at a rear side in the rotation direction. For this reason, a middle region  121   a  is present in the hill portion  121  between the embossing protrusion  122  and the hollow portion  123  at the rear side in the rotation direction. The middle region  121   a  is present at a higher position than the hollow portion  123  and at a lower position than the embossing protrusion  122  when viewed in a radial direction of the embossing roller  120 . For this reason, in terms of height, the middle region  121   a  is provided between the hollow portion  123  and the embossing protrusion  122 . The middle region  121  is provided to form the convexly swelling small region  52  on the upper layer sheet  11  of the top sheet  10 . Therefore, the middle region  121   a  is provided at a position adjacent to the hollow portion  123  for forming the large region  51  on the upper layer sheet  11 . In an example illustrated in  FIG. 9 , the embossing protrusion  122  is formed at a position close to the hollow portion  123  at the front side of the hill portion  121  in the rotation direction. However, the embossing protrusion  122  may be formed at a position close to the hollow portion  123  at the rear side of the hill portion  121  in the rotation direction. 
         [0134]    In addition, as illustrated in  FIG. 9 , the embossing roller  120  is preferably connected to a suction device  124 . A known device that sucks air using a fan, etc. may be employed as the suction device  124 . In addition, as illustrated in  FIG. 9 , a suction hole  125  of the suction device  124  communicates with a bottom portion of the hollow portion  123  of the embossing roller  120 . For this reason, the upper layer sheet  11  pushed into the hollow portion  123  of the embossing roller  120  by the projection portion  112  of the pin roller  110  is partially sucked by the suction device  124  through the suction hole  125 . In this way, when a portion of the upper layer sheet  11  pushed into the hollow portion  123  is sucked using the suction device  124 , the large region  51  formed on the upper layer sheet  11  may be swelled more. 
         [0135]    A peripheral surface of the plane roller  130  corresponds to a smooth surface. The plane roller  130  is provided to interpose the upper layer sheet  11  and the lower layer sheet  12  of the top sheet  10  between the embossing protrusions  122  of the embossing roller  120  and the plane roller  130  to press and heat the sheets, thereby heat-fusing the sheets. The peripheral surface of the plane roller  130  may be made of metal or rubber. In addition, the peripheral surface of the plane roller  130  may be heated by the heating device (not illustrated). 
         [0136]    As illustrated in  FIG. 9 , the pin roller  110  and the embossing roller  120  are disposed to face each other, and the upper layer sheet  11  introduced between both sheets. In addition, the embossing roller  120  and the plane roller  130  are disposed to face each other, and the upper layer sheet  11  and the lower layer sheet  12  are introduced in an overlapping state between both rollers. 
         [0137]    Next, an operation of the manufacturing apparatus will be described. As illustrated in  FIG. 9 , the upper layer sheet  11  drawn from an original fabric roll (not illustrated) is introduced between the pin roller  110  and the embossing roller  120  via one or a plurality of guide rollers (not illustrated). Referring to the upper layer sheet  11 , the non-skin facing surface (surface not directly coming into contact with the skin of the wearer) comes into contact with the pin roller  110 , and the skin facing surface (surface directly coming into contact with the skin of the wearer) comes into contact with the embossing roller  120 . In this instance, the upper layer sheet  11  is fit to the hollow portion  123  of the embossing roller  120  while being pressed against the projection portion  112  of the pin roller  110 . At the same time, a portion of the upper layer sheet  11  fit to the hollow portion  123  is sucked by the suction device  124  through the suction hole  125  provided in the bottom portion of the hollow portion  123 . In this way, the portion of the upper layer sheet  11  fit to the hollow portion  123  convexly swells. In this way, a portion that swells in a dome shape toward the skin facing surface side, that is, the large region  51  of the non-joining portion  50  is formed on the upper layer sheet  11 . Thereafter, the upper layer sheet  11  is introduced between the embossing roller  120  and the plane roller  130  while coming into contact with the peripheral surface of the embossing roller  120 . 
         [0138]    Meanwhile, the lower layer sheet  12  drawn from another original fabric roll (not illustrated) is introduced between the embossing roller  120  and the plane roller  130  via one or a plurality of guide rollers (not illustrated). The upper layer sheet  11  and the lower layer sheet  12  overlap each other between the embossing roller  120  and the plane roller  130 . In this instance, the skin facing surface side of the upper layer sheet  11  comes into contact with the embossing roller  120 , and the non-skin facing surface side of the lower layer sheet  12  comes into contact with the plane roller  130 . The upper layer sheet  11  and the lower layer sheet  12  are interposed between the embossing roller  120  and the plane roller  130  in a stacked state, and heat-fused by being heated and pressed. In this instance, the upper layer sheet  11  and the lower layer sheet  12  are heat-fused according to an embossing pattern of the plurality of embossing protrusions  122  formed on the peripheral surface of the embossing roller  120 . In this way, a plurality of concave joining portions  40  hollowed toward the non-skin facing surface side is formed on the top sheet  10 . Meanwhile, the upper layer sheet  11  is not joined to the lower layer sheet  12  in a region corresponding to the middle region  121   a  positioned between the embossing protrusion  122  and the hollow portion  123  in the embossing roller  120 . However, in the region corresponding to the middle region  121   a , the upper layer sheet  11  is not fit to the hollow portion  123  of the embossing roller  120 . For this reason, in the region corresponding to the middle region  121   a , while the upper layer sheet  11  swells to be higher than the joining portion  40 , and the upper layer sheet  11  is lower than the large region  51  of the non-joining portion  50 . Therefore, a portion slightly swelling in a dome shape toward the skin facing surface side, that is, the small region  52  of the non-joining portion  50  is formed in the region corresponding to the middle region  121   a . In this way, in the upper layer sheet  11  and the lower layer sheet  12 , a region touching the embossing protrusion  122  of the embossing roller  120  corresponds to the joining portion  40 , and a region surrounded by a plurality of joining portions  40  corresponds to the large region  51  or the small region  52  of the non-joining portion  50 . In this way, when the upper layer sheet  11  and the lower layer sheet  12  are joined using the embossing roller  120  after the upper layer sheet  11  is pressed by the pin roller  110 , the large region  51  and the small region  52  of the non-joining portion  50  may have a dome shape holding a space therein. 
         [0139]    Further, a description will be given of a method of forming the non-joining portion  50  having the crush point  53  with reference to  FIG. 10 .  FIG. 10  and  FIG. 9  illustrate substantially the same apparatus. However, a cross-section view of  FIG. 10  illustrates a cross section of a different portion from that of  FIG. 9 . As illustrated in  FIG. 10 , when the crush point  53  is formed in the large region  51  of the non-joining portion  50 , a portion of the hollow portion  123  of the embossing roller  120  illustrated in  FIG. 9  is eliminated to form the hill portion  121 , and a crush point protrusion  126  for forming the crush point  53  is provided in the portion. In other word, in order to form the crush point  53 , the hill portion  121  is formed instead of the hollow portion  123  that swells the large region  51 , and the crush point protrusion  126  is provided on the hill portion  121  provided instead of the hollow portion  123 . In addition, when the hill portion  121  is provided instead of the hollow portion  123 , a portion of the projection portion  112  of the pin roller  110  is unnecessary. 
         [0140]    The crush point protrusion  126  formed on the peripheral surface of the embossing roller  120  interposes the upper layer sheet  11  and the lower layer sheet  12  between the crush point protrusion  126  and the smooth surface of the plane roller  130 , and presses the upper layer sheet  11  toward the lower layer sheet  12  side. In this instance, similarly to the embossing protrusion  122 , the crush point protrusion  126  may join (heat-fuse) the upper layer sheet  11  and the lower layer sheet  12  to each other. Alternatively, the crush point protrusion  126  may simply press the upper layer sheet  11  without joining the upper layer sheet  11  and the lower layer sheet  12  to each other. In this way, the crush point  53  at which the upper layer sheet  11  and the lower layer sheet  12  are pressed or joined is formed by the crush point protrusion  126  in the large region  51  of the non-joining portion  50  of the top sheet  10 . As described in the foregoing, when the crush point  53  is formed, the upper layer sheet  11  is inhibited from swelling, and thus a space, which is normally formed in the large region  51  of the non-joining portion  50 , is narrowed or eliminated. In addition, the shape of the upper layer sheet  11  including nonwoven fabric, etc. is restored to swell around the crush point  53 , and thus the small wall portion  54  is formed around the crush point  53  (see  FIGS. 8( a ) and 8( b ) ). In this way, according to the apparatus illustrated in  FIG. 10 , it is possible to form the joining portion  40  for embossing in the upper layer sheet  11  and the lower layer sheet  12 , and to form the crush point  53  for controlling the diffusion direction of the liquid at the same time. 
       3. Joining Portion Non-Forming Region 
       [0141]    Next, a description will be given of an example of a case in which a joining portion non-forming region  80  is formed in the top sheet  10  of the invention with reference to  FIG. 11  to  FIG. 13 . The joining portion non-forming region  80  described below may be formed in both the first embodiment and the second embodiment described above. 
         [0142]      FIG. 11  is an example of a plan view of the top sheet.  FIG. 12  is an enlarged view of an inside of a dotted frame illustrated in  FIG. 11 . As illustrated in  FIG. 11 , the top sheet  10  is divided into a plurality of joining portion forming regions  70  and a plurality of joining portion non-forming regions  80 . The joining portion forming regions  70  are regions in which the above-described joining portions  40  are formed in at least a portion along the width direction (X-axis direction) of the absorbent article. In other words, when a virtual straight line is drawn along the width direction in the joining portion forming regions  70 , the joining portions  40  are positioned on the straight line. In the present embodiment, the joining portions  40  are disposed substantially in zigzag, and thus a portion in which the joining portions  40  are regularly formed corresponds to the joining portion forming regions  70 . Meanwhile, each of the plurality of joining portion non-forming regions  80  is formed between joining portion forming regions  70 . The joining portion non-forming regions  80  are regions in which the above-described joining portions  40  are not formed across the whole in the width direction (X-axis direction) of the absorbent article. In other words, when a virtual straight line is drawn along the width direction in the joining portion non-forming regions  80 , no joining portion  40  is positioned on the straight line. In the present embodiment, in order to from the joining portion non-forming regions  80 , a portion of the shape of the λ-shaped joining portion  40  is modified such that no joining portion  40  is present across the whole width direction. 
         [0143]    In the embodiment illustrated in  FIG. 11 , the joining portion non-forming regions  80  are provided in three positions. The three respective joining portion non-forming regions  80  are set to a first region  81 , a second region  82 , and a third region  83 . Herein, in  FIG. 11 , vertical widths (lengths in the longitudinal direction of the absorbent article) of the first region  81 , the second region  82 , and the third region  83  are indicated by symbols S 1 , S 2 , and S 3 , respectively. Herein, the vertical widths S 1 , S 2 , and S 3  of the first to third regions  81 ,  82 , and  83  are different from one another. Specifically, the vertical width S 1  of the first region  81  is the widest width, the vertical width S 2  of the second region  82  is the second widest width, and the vertical width S 3  of the third region  83  is the narrowest width (S 1 &gt;S 2 &gt;S 3 ). In this way, the plurality of joining portion non-forming regions  80  is preferably formed in at least two or more types of vertical widths, and particularly in three or more types of vertical widths. A joining portion non-forming region  80  having a wide vertical width may smoothly lead urine inside a capillary tube even when the urine is in a state in which salinity concentration and viscosity are high and a movement driving force is small. For this reason, the joining portion non-forming region  80  having the wide vertical width is suitable for diffusion of urine having high salinity concentration. Meanwhile, a joining portion non-forming region  80  having a narrow vertical width may effectively diffuse a liquid in the width direction even when the amount of the liquid is small. Furthermore, the joining portion non-forming region  80  having the narrow vertical width is suitable for diffusion of urine having low salinity concentration. Therefore, it is preferable to provide joining portion non-forming regions  80  having different vertical widths to be able to respond to a change in salinity concentration of urine. 
         [0144]    For example, the vertical width S 1  of the first region  81  corresponding to the widest width is preferably set to a range of 6 mm to 10 mm, and particularly preferably set to 8 mm. In addition, the vertical width S 2  of the second region  82  corresponding to the second widest width is preferably set to a range of 4 mm to 8 mm, and particularly preferably set to 6 mm. In addition, the vertical width S 3  of the third region  83  corresponding to the widest width is preferably set to a range of 2 mm to 6 mm, and particularly preferably set to 4 mm. However, a relation of S 1 &gt;S 2 &gt;S 3  is satisfied. 
         [0145]    In addition, in  FIG. 11 , a vertical width (length in the longitudinal direction of the absorbent article) of the joining portion forming region  70  is indicated by a symbol S 0 . The joining portion forming regions  70  are present at a plurality of positions, and vertical widths thereof may be different from each other. However, herein, symbols indicating the vertical widths of the plurality of joining portion forming regions  70  are conveniently uniformly set to S 0 . The vertical width S 0  of the joining portion forming region  70  may be twice or more the vertical width S 1  of the first region  81  which is the widest among the plurality of joining portion non-forming regions  80  ( 81  to  83 ) (S 0 ≧2·S 1 ). In particular, the vertical width S 0  of the joining portion forming region  70  is preferably three times or more the vertical width S 1  of the first region  81 , and more preferably five times or seven times the vertical width S 1  of the first region  81 . When the vertical width of the joining portion forming region  70  is narrow, it is difficult to obtain softness and air permeability improvement effects resulting from embossing assigned to the joining portion forming region  70 . Thus, the vertical width of the joining portion forming region  70 , which is wide to some extent, is preferably ensured. Specifically, the vertical width S 0  of the joining portion forming region  70  is preferably 40 mm or more or 60 mm. For example, an upper limit thereof may be set to 100 mm or 150 mm. 
         [0146]    In the present embodiment, the joining portion non-forming regions  80  ( 81  to  83 ) are arranged such that the vertical widths are in order of S 1 -S 2 -S 3  (S 1 &gt;S 2 &gt;S 3 ) when viewed in the longitudinal direction (X-axis direction). When the plurality of joining portion non-forming regions  80  is arranged such that the vertical widths thereof gradually narrows in the longitudinal direction, it is possible to effectively respond to an individual difference in salinity concentration of urine. However, for example, the joining portion non-forming regions  80  may be arranged in order of S 2 -S 1 -S 3  or in order of S 1 -S 3 -S 2  when viewed in the longitudinal direction. 
         [0147]    In addition, in the present embodiment, the joining portion non-forming regions  80  different in vertical width are formed only in three positions. However, the number of joining portion non-forming regions  80  may be appropriately adjusted according to a size of the absorbent article, etc. For example, the number of joining portion non-forming regions  80  may be set to five to ten. In this case, all the plurality of joining portion non-forming regions  80  may be different in vertical width, or the joining portion non-forming regions  80  having the same vertical width may be provided in a plurality of positions. For example, when the number of joining portion non-forming regions  80  is six, the joining portion non-forming regions  80  may be arranged by being regularly repeated such that vertical widths correspond to S 1 -S 2 -S 3 -S 1 -S 2 -S 3  (S 1 &gt;S 2 &gt;S 3 ) when viewed in the longitudinal direction (X-axis direction). 
         [0148]    In addition, in the present embodiment, the respective joining portion non-forming regions  80  in the three positions are different in vertical width. However, at least one of the vertical widths of the plurality of joining portion non-forming regions  80  may be different. For example, when the joining portion non-forming regions  80  are provided in three positions, vertical widths may be set to S 1 -S 2 -S 2  (S 1 &gt;S 2 ) when viewed in the longitudinal direction such that a joining portion non-forming region  80  having a wide vertical width (S 1 ) is provided only in one position, and vertical widths (S 2 ) in the other two positions may be identical to each other. In addition, for example, when the number of joining portion non-forming regions  80  is six, vertical widths thereof may be set to S 1 -S 2 -S 2 -S 1 -S 2 -S 2  (S 1 &gt;S 2 ) when viewed in the longitudinal direction. 
         [0149]      FIG. 13  illustrates a cross-sectional shape along C-C line illustrated in  FIG. 12 . That is,  FIG. 13  illustrates a cross-sectional view of the joining portion non-forming region  80  in the longitudinal direction. As illustrated in  FIG. 13 , in the joining portion non-forming region  80 , the joining portions  40  are not formed, and thus the upper layer sheet  11  and the lower layer sheet  12  are separated from each other. In addition, in  FIG. 13 , a swelling height of the upper layer sheet  11  in the joining portion non-forming region  80  is indicated by a symbol H 4 . In addition, in  FIG. 13 , a swelling height of the upper layer sheet  11  in the small region  52  described above in the non-joining portion  50  surrounded by the joining portions  40  is indicated by a symbol H 1 . In this case, the swelling height H 4  of the upper layer sheet  11  in the joining portion non-forming region  80  is preferably the same as the swelling height H 1  of the upper layer sheet  11  in the small region  52  or lower than the swelling height H 1  (H 4 ≦H 1 ). For example, the swelling height H 4  is preferably in a range of 30% to 100%, 40% to 90%, or 50% to 80% with respect to the swelling height H 1 . When the swelling height H 4  in the joining portion non-forming region  80  is set to be identical to or preferably set to be lower than the swelling height H 1  in the small region  52  in this way, excreta such as urine, a loose passage, etc. is easily diffused in the width direction through the joining portion non-forming region  80  linearly formed across the whole top sheet  10  in the width direction. 
       4. Characteristic of the Invention from Another Point of View 
       [0150]    Next, a description will be given of a case in which the top sheet according to the invention is specified from another point of view with reference to  FIG. 14  to  FIG. 17 . 
         [0151]    An issue to be solved by the invention described below is to provide a top sheet, absorption performance of which is not impaired in a region in which the top sheet is fully or partially folded, and thus surfaces thereof adhere to each other. In addition, as a result of a keen examination of solution to such an issue, the inventors of the invention have determined to set a shape of a joining portion group positioned around one non-joining region to an asymmetric shape in a regular embossing pattern formed on a surface of the top sheet. When the shape of the joining portion group is set to the asymmetric shape (including front-rear line asymmetry, left-right line asymmetry, or rotational asymmetry) in this way, joining portions may not fully overlap each other even in a state in which the top sheet is fully or partially folded in half, and thus surfaces thereof adhere to each other. In this way, a liquid such as urine may be effectively absorbed even in a region in which the top sheet is folded. 
         [0152]    A description will be given of an embossing pattern formed on the top sheet  10 .  FIG. 14  is an enlarged view illustrating components included in one non-joining portion  50  in the embossing pattern assigned to the top sheet by extracting the components.  FIG. 14  is a cross section corresponding to previously described  FIG. 3 . 
         [0153]    As illustrated in  FIG. 14 , the embossing pattern of the top sheet  10  includes a plurality of joining portions  40  that joins the upper layer sheet  11  and the lower layer sheet  12  to each other, and a plurality of non-joining portions  50  surrounded by the plurality of joining portions  40 . The plurality of joining portions  40  is regularly disposed at intervals. Specifically, a plurality of joining portions  40  having the same shape, size, and direction is disposed by being arranged in column shapes at certain intervals in the longitudinal direction, and a plurality of columns of the joining portions  40  is formed in the width direction. In addition, in adjacent columns of joining portions  40 , the respective joining portions  40  are differently arranged in the longitudinal direction, and a so-called zigzag arrangement is formed. In addition, the respective joining portions  40  are arranged on straight lines in the longitudinal direction and the width direction. 
         [0154]    In the joining portions  40 , the upper layer sheet  11  and the lower layer sheet  12  are heat-fused together. For this reason, the upper layer sheet  11  is concavely hollowed in the joining portions  40 . Meanwhile, the non-joining portions  50  correspond to regions surrounded by the plurality of joining portions  40 , that is, regions in which the upper layer sheet  11  and the lower layer sheet  12  are not joined to each other. For this reason, when compared to the joining portions  40 , the non-joining portions  50  convexly swells in a direction in which the upper layer sheet  11  touches the skin of the wearer. As illustrated in  FIG. 14 , in the top sheet  10  of the invention, the joining portions  40  and the non-joining portions  50  have novel shapes which have not been present in the past. 
         [0155]    As illustrated in  FIG. 14 , in the invention, the plurality of joining portions  40  are disposed around the non-joining portion  50 , and the non-joining portion  50  is demarcated in this way. Herein, in this specification, the plurality of joining portions  40  disposed to surround one non-joining portion is collectively referred to as a “joining portion group”. In  FIG. 14 , a plurality of joining portions  40  included in a certain “joining portion group” is conceptually indicated by a dotted line. In the embodiment illustrated in  FIG. 14 , the joining portion group includes three joining portions  40 . 
         [0156]    As illustrated in  FIG. 14 , in the invention, the joining portion group has an asymmetric shape. Specifically, firstly, a center C of the non-joining portion  50  is determined. The center C of the non-joining portion corresponds to a point at which a straight line which extends along the longitudinal direction and divides a maximum width of the non-joining portion  50  into two equal parts intersects a straight line which extends along the width direction and divides a maximum length of the non-joining portion  50  into two equal parts. Herein, firstly, the joining portion group has a line asymmetric shape, that is, a front-rear line asymmetric shape with respect to a symmetry axis H along the width direction passing through the center C of the non-joining portion  50 . That is, even when the joining portion group is folded in half along the symmetry axis H illustrated in  FIG. 14 , the joining portion group has a shape in which folded parts do not fully overlap in mirror symmetry. Further, the joining portion group has a line asymmetric shape, that is, a left-right line asymmetric shape with respect to a symmetry axis V along the longitudinal direction passing through the center C of the non-joining portion  50 . That is, even when the joining portion group is folded in half along the symmetry axis V illustrated in  FIG. 14 , the joining portion group has a shape in which folded parts do not fully overlap in mirror symmetry. 
         [0157]    When the shape of the joining portion group is set to the front-rear line asymmetric shape and the left-right line asymmetric shape in this way, parts of the joining portion  40  may be inhibited from fully overlapping each other even in a state in which the top sheet  10  is fully or partially folded in half in the longitudinal direction or the width direction, and surfaces thereof adhere to each other. In other words, when the top sheet is folded in half in a conventional embossing pattern, recessed joining portions fully overlap each other as in mirror symmetry, and a large gap is generated in the overlapping portion. In addition, referring to the large gap generated on the surface of the top sheet, a liquid such as urine may pass by the gap without being absorbed, or the liquid may accumulate in the gap. Therefore, there has been a problem that there is a concern that absorption performance of the top sheet may be impaired in a region in which the surfaces of the top sheet overlap each other. On the other hand, for example, when the shape of the joining portion group is set to the front-rear line asymmetric shape and the left-right line asymmetric shape as in an example illustrated in  FIG. 14 , the joining portions  40  may be inhibited from fully overlapping each other even when the top sheet  10  is fully or partially folded in half. Therefore, according to the invention, the liquid such as urine may be effectively absorbed even in a region in which the top sheet  10  is folded. 
         [0158]    In addition, as in the example illustrated in  FIG. 14 , the shape of the joining portion group preferably corresponds to a shape not having rotational symmetry (rotationally asymmetric shape) using the center C of the non-joining portion  50  as a center of symmetry. In this way, not only when the top sheet  10  is folded in half in the longitudinal direction and the width direction, but also when the top sheet  10  is folded in half in an arbitrary direction, the joining portions  40  forming the joining portion group do not fully overlap in mirror symmetry. 
         [0159]    Further, all the plurality of joining portions  40  included in the joining portion group preferably has the same shape. Similarly to the previously described shape of the joining portion  40 , in the embodiment of  FIG. 14 , each of the joining portions  40  has a λ-shape branching off in three directions. All the respective joining portions  40  have the same shape, size, and direction, and are regularly arranged in zigzag. In this way, when the shapes of the respective joining portions  40  are identical to each other, the top sheet  10  may be joined without unevenness. In other words, when a plurality of joining portions having different shapes, sizes, and directions is formed, there is a possibility that the upper layer sheet  11  and the lower layer sheet  12  may fail to be fusion-bonded to each other in a joining portion having a complex shape or in a small joining portion. On the other hand, when the shapes of the joining portions  40  are identical to each other, the upper layer sheet  11  and the lower layer sheet  12  may be more reliably fusion-bonded to each other. 
         [0160]    In addition, each of the plurality of joining portions  40  included in the joining portion group preferably corresponds to a shape not having rotational symmetry. In a conventional embossing pattern, a joining portion corresponds to a shape having rotational symmetry such as a circular shape, a triangular shape, a rectangular shape, a cross shape, a star shape, etc. On the other hand, as illustrated in  FIG. 14 , in the invention, the joining portion  40  corresponds to a shape not having rotational symmetry (rotationally asymmetric shape). In this way, even when the top sheet  10  is folded in half along a polygonal line passing through a certain joining portion  40 , parts of the joining portion  40  may be inhibited from fully overlapping each other in mirror symmetry. In other words, in the invention, the shape of the joining portion  40  preferably corresponds to a shape in which parts of the joining portion  40  do not overlap each other irrespective of how the joining portion  40  is folded in half. 
         [0161]    The top sheet according to the embodiment illustrated in  FIG. 14  may basically employ a similar configuration to that of the embodiment described with reference to  FIG. 1  to  FIG. 13 . The description related to  FIG. 1  to  FIG. 13  may be quoted in a description of a specific structure of the top sheet, and a detailed description will be omitted here. 
         [0162]    Hereinafter, a description will be given of a modified example of the top sheet according to the embodiment illustrated in  FIG. 14 . 
       4-1. First Modified Example 
       [0163]      FIG. 15  illustrates a first modified example of the embossing pattern formed on the top sheet. As illustrated in  FIG. 15 , in the first modified example, a joining portion group including a plurality of joining portions  40  that surrounds one non-joining portion  50  has an asymmetric shape similarly to the embodiment of  FIG. 14 . In more detail, in Modified Example 1, the joining portion group satisfies requirements below. 
         [0164]    (1) The joining portion group is not in line symmetry with respect to the symmetry axis H along the width direction (front-rear line asymmetry). 
         [0165]    (2) The joining portion group is not in line symmetry with respect to the symmetry axis V along the longitudinal direction (left-right line asymmetry). 
         [0166]    (3) The joining portion group is not in rotational symmetry using the center C of the non-joining portion  50  as a center of symmetry (rotational asymmetry). 
         [0167]    (4) All the plurality of joining portions  40  included in the joining portion group is identical to each other. 
         [0168]    (5) Each of the plurality of joining portions  40  included in the joining portion group is not in rotational symmetry. 
         [0169]    Specifically, as illustrated in  FIG. 15 , in the embossing pattern according to the first modified example, a joining portion  40  has a shape in which a first line portion  41 , a second line portion  42 , and a third line portion  43  branch off from a junction  44  thereof in different directions. In other words, proximal ends (one ends) of the first line portion  41 , the second line portion  42 , and the third line portion  43  are connected at the junction  44 , and distal ends (the other ends) of the first line portion  41 , the second line portion  42 , and the third line portion  43  are directed in different directions. In addition, at least the first line portion  41  and the second line portion  42  have a shape curved in a circular arc shape or an S-shape, or a shape bent at one or more turning points. In the example illustrated in  FIG. 15 , the first line portion  41  has the circular arc shape, and the second line portion  23  is bent in the S-shape. As illustrated in  FIG. 15 , referring to the circular arc-shaped first line portion  41  and the S-shaped second line portion  42 , directions in which arcs bulge out (directions in which the arcs warp) correspond to the same direction around the junction  44 . In other words, when the first line portion  41  and the second line portion  42  are connected to each other, a soft and large S-shape is formed. In addition, the third line portion  43  may have a circular arc shape similarly to the first line portion  41  and the second line portion  42 , or have a linear shape. In addition, directions in which the first line portion  41  and the second line portion  42  extend are substantially orthogonal to a direction in which the third line portion  43  extends. 
         [0170]    In addition, as illustrated in  FIG. 15 , the first line portion  41 , the second line portion  42 , and the third line portion  43  have different lengths. In the example illustrated in  FIG. 15 , the second line portion  42  is longer than the first line portion  41 , and the first line portion  41  is longer than the third line portion  43  (the second line portion  42 &gt;the first line portion  41 &gt;the third line portion  43 ). In addition, when all the respective line portions  41  to  43  are formed in circular arc shapes, curvatures (or radii of curvatures) of the respective line portions  41  to  43  may be different from one another or identical to one another. 
         [0171]    As illustrated in  FIG. 15 , the joining portions  40  having the above-described shapes are regularly disposed at intervals. Specifically, a plurality of joining portions  40  having the same shape, size, and direction is disposed by being arranged in column shapes at certain intervals in the longitudinal direction, and a plurality of columns of the joining portions  40  is formed in the width direction. In addition, in adjacent columns of joining portions  40 , the respective joining portions  40  are differently arranged in the longitudinal direction, and a so-called zigzag arrangement is formed. In addition, the respective joining portions  40  are arranged on straight lines in the longitudinal direction and the width direction. In this way, the non-joining portion  50  is formed to be surrounded by three joining portions  40 . As illustrated in  FIG. 15 , a substantially circular large region  51  and a substantially rectangular small region  52  are present as the non-joining portion  50 . In the first modified example, the joining portion  40  is positioned between the large region  51  and the small region  52 . The first modified example is different from the above-described embodiment of  FIG. 14  in this regard. 
       4-2. Second Modified Example 
       [0172]      FIG. 16  illustrates an enlarged view of an embossing pattern formed on the top sheet according to a second modified example. As illustrated in  FIG. 16 , in the second modified example, a joining portion group including a plurality of joining portions  40  that surrounds one non-joining portion  50  has an asymmetric shape similarly to the embodiment of  FIG. 14 . In more detail, in the second modified example, the joining portion group satisfies requirements below. 
         [0173]    (1) The joining portion group is not in line symmetry with respect to the symmetry axis H along the width direction (front-rear line asymmetry). 
         [0174]    (2) The joining portion group is not in line symmetry with respect to the symmetry axis V along the longitudinal direction (left-right line asymmetry). 
         [0175]    (3) The joining portion group is not in rotational symmetry using the center C of the non-joining portion  50  as a center of symmetry (rotational asymmetry). 
         [0176]    (4) All the plurality of joining portions  40  included in the joining portion group is identical to each other. 
         [0177]    (5) Each of the plurality of joining portions  40  included in the joining portion group is not in rotational symmetry. 
         [0178]    Specifically, as illustrated in  FIG. 16 , in the embossing pattern according to the second modified example, a joining portion  40  has a shape in which a first line portion  41 , a second line portion  42 , and a third line portion  43  branch off from a junction  44  thereof in different directions. In other words, proximal ends (one ends) of the first line portion  41 , the second line portion  42 , and the third line portion  43  are connected at the junction  44 , and distal ends (the other ends) of the first line portion  41 , the second line portion  42 , and the third line portion  43  are directed in different directions. In addition, at least the first line portion  41  has a shape curved in a circular arc shape, or a shape bent at one or more turning points. In the example illustrated in  FIG. 16 , the first line portion  41  has the circular arc shape. Meanwhile, the second line portion  42  and the third line portion  43  may have a circular arc shape similarly to the first line portion  41 , and may have a linear shape. In addition, directions in which the second line portion  42  and the third line portion  43  extend are substantially orthogonal to each other. 
         [0179]    In addition, as illustrated in  FIG. 16 , the first line portion  41 , the second line portion  42 , and the third line portion  43  have different lengths. Meanwhile, the second line portion  42  and the third line portion  43  have substantially the same length. In the example illustrated in  FIG. 16 , the first line portion  41  is longer than the second line portion  42  and the third line portion, and the second line portion  42  has substantially the same length as that of the third line portion  43  (the first line portion  41 &gt;the second line portion  42 =the third line portion  43 ). In addition, when all the respective line portions  41  to  43  are formed in circular arc shapes, curvatures (or radii of curvatures) of the respective line portions  41  to  43  may be different from one another or identical to one another. In addition, as illustrated in  FIG. 16 , a substantially semi-circular shape is formed when the first line portion  41  is connected to the third line portion  43 . 
         [0180]    As illustrated in  FIG. 16 , the joining portions  40  having the above-described shapes are regularly disposed at intervals. Specifically, a plurality of joining portions  40  having the same shape, size, and direction is disposed by being arranged in column shapes at certain intervals in the longitudinal direction, and a plurality of columns of the joining portions  40  is formed in the width direction. In addition, in adjacent columns of joining portions  40 , the respective joining portions  40  are differently arranged in the longitudinal direction, and a so-called zigzag arrangement is formed. In addition, the respective joining portions  40  are arranged on straight lines in the longitudinal direction and the width direction. In this way, the non-joining portion  50  is formed to be surrounded by three joining portions  40 . As illustrated in  FIG. 16 , a substantially circular large region  51  and a substantially rectangular small region  52  are present as the non-joining portion  50 . In the second modified example, the joining portion  40  is positioned between the large region  51  and the small region  52 . The second modified example is different from the above-described embodiment of  FIG. 14  in this regard. 
       4-2. Third Modified Example 
       [0181]      FIG. 17  illustrates an enlarged view of an embossing pattern formed on the top sheet according to a third modified example. As illustrated in  FIG. 17 , in the third modified example, a joining portion group including a plurality of joining portions  40  that surrounds one non-joining portion  50  has an asymmetric shape similarly to the embodiment of  FIG. 14 . In more detail, in the third modified example, the joining portion group satisfies requirements below. 
         [0182]    (1) The joining portion group is not in line symmetry with respect to the symmetry axis H along the width direction (front-rear line asymmetry). 
         [0183]    (2) The joining portion group is not in line symmetry with respect to the symmetry axis V along the longitudinal direction (left-right line asymmetry). 
         [0184]    (3) The joining portion group is not in rotational symmetry using the center C of the non-joining portion  50  as a center of symmetry (rotational asymmetry). 
         [0185]    (4) All the plurality of joining portions  40  included in the joining portion group is identical to each other. 
         [0186]    (5) Each of the plurality of joining portions  40  included in the joining portion group is not in rotational symmetry. 
         [0187]    Specifically, as illustrated in  FIG. 17 , in the embossing pattern according to the third modified example, a joining portion  40  has a shape in which a first line portion  41 , a second line portion  42 , a third line portion  43 , and a fourth line portion  45  branch off from a junction  44  thereof in different directions. In the third modified example, the junction  44  forms a linear shape having a certain length. In addition, the first line portion  41  and the fourth line portion  45  are connected to one end of the linear junction  44 , and the second line portion  42  and the third line portion  43  are connected to the other end of the linear junction  44 . In addition, at least the first line portion  41  has a shape curved in a circular arc shape, or a shape bent at one or more turning points. In the example illustrated in  FIG. 17 , the first line portion  41  has the circular arc shape. In addition, the second line portion  42 , the third line portion  43 , and the fourth line portion  45  may have a circular arc shape or a linear shape. In addition, directions in which the first line portion  41  and the fourth line portion  45  extend are substantially orthogonal to each other, and directions in which the second line portion  42  and the third line portion extend are substantially orthogonal to each other. 
         [0188]    In addition, as illustrated in  FIG. 17 , the first line portion  41 , the second line portion  42 , the third line portion  43 , and the fourth line portion  45  have different lengths. In the example illustrated in  FIG. 17 , the first line portion  41  is longer than the other line portions  42 ,  43 , and  45 , and the other line portions  42 ,  43 , and  45  have substantially the same length (the first line portion  41 &gt;the second line portion  42 =the third line portion  43 =the fourth line portion  45 ). In addition, when all the respective line portions  41 ,  42 ,  43 , and  45  are formed in circular arc shapes, curvatures (or radii of curvatures) of the respective line portions may be different from one another or identical to one another. 
         [0189]    As illustrated in  FIG. 17 , the joining portions  40  having the above-described shapes are regularly disposed at intervals. Specifically, a plurality of joining portions  40  having the same shape, size, and direction is disposed by being arranged in column shapes at certain intervals in the longitudinal direction, and a plurality of columns of the joining portions  40  is formed in the width direction. In addition, in adjacent columns of joining portions  40 , the respective joining portions  40  are differently arranged in the longitudinal direction, and a so-called zigzag arrangement is formed. In addition, the respective joining portions  40  are arranged on straight lines in the longitudinal direction and the width direction. In this way, the non-joining portion  50  is formed to be surrounded by three joining portions  40 . As illustrated in  FIG. 17 , a substantially circular large region  51  and a substantially rectangular small region  52  are present as the non-joining portion  50 . In the third modified example, the joining portion  40  is positioned between the large region  51  and the small region  52 . The third modified example is different from the above-described embodiment of  FIG. 14  in this regard. 
         [0190]    Hereinbefore, in this specification, the embodiments of the invention have been described with reference to the drawings to represent content of the invention. However, the invention is not restricted to the above-described embodiments, and includes a modified mode or an improved mode clear to those skilled in the art based on information described in this specification. 
       INDUSTRIAL APPLICABILITY 
       [0191]    The invention relates to a top sheet for an absorbent article such as a disposable diaper. For this reason, the invention may be suitably used in a disposable diaper manufacturing industry, etc. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           10  top sheet 
           11  upper layer sheet 
           12  lower layer sheet 
           20  back sheet 
           30  absorber 
           40  joining portion 
           41  first line portion 
           42  second line portion 
           43  third line portion 
           44  junction 
           50  non-joining portion 
           51  large region 
           52  small region 
           61  first gap 
           62  second gap 
           63  third gap 
           70  joining portion forming region 
           80  joining portion non-forming region 
           100  absorbent article 
           110  pin roller 
           111  projection portion 
           120  embossing roller 
           121  hill portion 
           121   a  middle region 
           122  embossing protrusion 
           123  hollow portion 
           124  suction device 
           125  suction hole 
           126  crush point protrusion 
           130  plane roller