Patent Publication Number: US-2015065983-A1

Title: Disposable diaper

Description:
TECHNICAL FIELD 
     The present invention relates to a disposable diaper including side flaps at side edges in the product widthwise direction of an absorbent body, and, in particular, to a disposable diaper which attempts to reduce the stimulation on the skin in the vicinity of leg hole portions of a wearer, caused by elastic members provided to the side flaps. 
     BACKGROUND ART 
     Conventionally, various disposable diapers have been devised to realize a good fit while ensuring to prevent leakage of bodily waste. For example, there is known a disposable diaper configured so that an interval in a front waistline unit between a pair of leg hole elastic members is larger than an interval in a back waistline unit between these elastic members (see Patent Literature 1). 
     According to the above disposable diaper, a pocket (room) is formed in the front waistline unit, so that an absorber having enough size to fully absorb bodily waste can be arranged in the front waistline unit. Therefore, it is contemplated that the leakage can be effectively prevented from the front waistline unit which practically receives a larger volume of urine excreted. 
     CITATION LIST 
     Patent Literature 
     [PTL 1]
     Japanese Unexamined Patent Application Publication No. H11-47189 (FIG. 1)   

     SUMMARY OF INVENTION 
     Technical Problem 
     However, the conventional disposable diaper described above has the following problems. That is, since the leg hole elastic member is provided at each side end in the product widthwise direction, it is prone to bite into the skin of a wearer, thereby causing a problem of the stimulation given on the skin of a wearer. It becomes more of a problem especially in the case of a disposable diaper for infants and toddlers since the skin of infants and toddlers has poor resistance to this stimulation. 
     Therefore, the present invention has been achieved in view of the above-described situation, and an object thereof is to provide a disposable diaper which reduces more stimulation on the skin in the vicinity of the leg hole portions of a wearer while enhancing contact in the vicinity of leg holes. 
     Solution to Problem 
     An aspect of the present invention is summarized as a disposable diaper (disposable diaper  10 ), including: a front waistline unit (front waistline unit  20 ); a back waistline unit (back waistline unit  30 ); a crotch unit (crotch unit  25 ); a vertically long absorbent body (absorbent body  15 ) including a liquid-retaining absorber (absorber  40 ); a side flap (side flap  70 ) provided at each side edge in a product widthwise direction of the absorbent body; a leg hole opening unit (leg hole opening unit  35 ) that is concaved towards a center in the product widthwise direction of the absorbent body, and is formed at the each side edge in the product widthwise direction of the absorbent body; wherein the disposable diaper includes a sheet-like leg hole stretch unit (leg hole stretch unit  100 ) provided to a side end in the product widthwise direction (product widthwise direction W) of the side flap, extending in a product longitudinal direction (product longitudinal direction L), and being partially stretchable at least in the product longitudinal direction; a side edge in the product widthwise direction of the leg hole stretch unit is in a meandering shape in the product longitudinal direction; a distance (for example, distance d 1 ) between the side edge in the product widthwise direction of the leg hole stretch unit and a straight line (center line CL) passing through a center in the product widthwise direction of the disposable diaper and extending in parallel to the product longitudinal direction changes from the front waistline unit to the back waistline unit; a plurality of concave units (concave unit  140 , concave unit  160 ) resulting from a shift of an amount of change in the distance from decrease to increase are provided closer to the back waistline unit than a center in the product longitudinal direction of the disposable diaper; and a width in the product widthwise direction of the leg hole stretch unit provided with the concave units is smaller than a width in the product widthwise direction of the leg hole stretch unit other than the concave units. 
     Advantageous Effects of Invention 
     According to the features of the present invention, it is possible to provide a disposable diaper which reduces more stimulation on the skin in the vicinity of the leg hole portions of a wearer while enhancing contact in the vicinity of leg holes. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an exploded plan view of a disposable diaper  10  according to an embodiment of the present invention. 
         FIG. 2  is an enlarged plan view of a leg hole stretch unit  100  according to the embodiment of the present invention. 
         FIG. 3  is a diagram illustrating schematically a cross section of the disposable diaper  10  taken along the line F 3 -F 3  shown in  FIG. 1 . 
         FIG. 4  is a diagram illustrating schematically a state in which the disposable diaper  10  according to the embodiment of the present invention is worn by a wearer. 
         FIG. 5  is an enlarged plan view of a leg hole stretch unit  100 A according to a modification of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an embodiment of a disposable diaper according to the present invention is described with reference to accompanying drawings. In the following description of the drawings, the same or similar reference numerals are used to designate the same or similar units. It will be appreciated that the drawings are schematically shown and the ratio and the like of each dimension are different from the real ones. 
     Accordingly, specific dimensions should be determined in consideration of the explanation below. Moreover, among the drawings, the respective dimensional relations or ratios may differ. 
     (1) Overall Schematic Configuration of Disposable Diaper 
       FIG. 1  is an exploded plan view of a disposable diaper  10  according to the present embodiment.  FIG. 2  is an enlarged plan view of a leg hole stretch unit  100 .  FIG. 3  is a diagram illustrating schematically a cross section of the disposable diaper  10  taken along the line F 3 -F 3  shown in  FIG. 1 . 
     As shown in  FIGS. 1 to 3 , the disposable diaper  10  has a front waistline unit  20 , a crotch unit  25 , and a back waistline unit  30 . The front waistline unit  20  is a part coming in contact with the front waistline portion of a wearer. Furthermore, the back waistline unit  30  is a part coming in contact with the back waistline portion of the wearer. The crotch unit  25  is positioned between the front waistline unit  20  and the back waistline unit  30 . An absorbent body  15  is configured by the front waistline unit  20 , the crotch unit  25 , and the back waistline unit  30 . Furthermore, a pair of leg hole concave units  35  (see  FIG. 4 ) are formed in the disposable diaper  10 . Specifically, the leg hole concave units  35  are formed at side edges in a product widthwise direction W of the absorbent body  15  and are concaved towards the center in the product widthwise direction W. The leg hole concave units  35  form openings formed from the front waistline unit  20  to the back waistline unit  30  by engaging fastening tapes  90  provided at the back waistline unit  30  with the front waistline unit  20 , i.e., with a target tape  65 , at the time of wearing the disposable diaper  10  by a wearer. 
     The leg hole concave units  35  are openings which are formed from the front waistline unit  20  to the back waistline unit  30  by engaging the fastening tapes  90  provided at the back waistline unit  30  with the front waistline unit  20  (target tape) at the time of wearing the disposable diaper  10  by a wearer. 
     In the present embodiment, the direction from the front waistline unit  20  towards the back waistline unit  30  is called the product longitudinal direction L, and the direction perpendicular to the product longitudinal direction L is called the product widthwise direction W. 
     The disposable diaper  10  includes an absorber  40  spanning the crotch unit  25  and extending in the front waistline unit  20  and the back waistline unit  30 . The absorbent body  15  has a vertically long shape including a liquid-retaining absorber  40 . The absorber  40  is made up of an absorbent core  40   a  and a core wrap  40   b.    
     The absorber  40  is same as in the conventional disposable diaper, and can be configured appropriately by using popular components and materials, such as ground pulp and high absorbent polymer. The absorbent core  40   a  is wrapped by the sheet-like core wrap  40   b.  The core wrap  40   b  is a sheet for wrapping the absorbent core  40   a.  A part of at least the skin surface contact side of the core wrap  40   b  is configured by various fibrous nonwoven fabrics or a tissue sheet having liquid-permeability. For example, an air-through fibrous nonwoven fabric, a spunbond nonwoven fabric, or an SMS (spunbond-meltblown-spunbond) nonwoven cloth having a mass of approximately 10 to 30 g/m 2 , or a tissue sheet having a mass of approximately 10 to 30 g/m 2  can be used. 
     A liquid-permeable topsheet  50  is provided at the top side (skin contact surface side) of the absorber  40 . Furthermore, a liquid-impermeable leakage-preventing film  55  is provided at the back side (non-skin contact surface side) of the absorber  40 . A backsheet  60  made of a nonwoven fabric is provided at the back side of the leakage-preventing film  55 . 
     A side flap  70  is provided at each side edge in the product widthwise direction W of the absorbent body  15 , from the front waistline unit  20  to the back waistline unit  30 . The side flap  70  is made of one or two or more pieces of nonwoven fabrics overlapping one another. Furthermore, a pair of side flaps  70  are provided with the fastening tapes  90 , respectively. Specifically, the side flaps  70  formed in the back waistline unit  30  are provided with the pair of fastening tapes  90  which are engageable with the front waistline unit  20 . 
     A pair of left-right leg hole stretch units  100  are formed at side ends in the product widthwise direction W of the side flaps  70 . The leg hole stretch units  100  extend in the product longitudinal direction L and are partially stretchable at least in the product longitudinal direction L. In the present embodiment, the leg hole stretch units  100  are regions including stretch sheets  200  (see  FIG. 1 ), and side edges in the product widthwise direction of the leg hole stretch units  100  are in a meandering shape in the product longitudinal direction L. The stretch sheets  200  are made of a stretchable nonwoven fabric sheet. 
     Furthermore, a pair of leg side gathers  80  extending in the product longitudinal direction L are provided at the inner side of the pair of leg hole stretch units  100  (towards the center in the product widthwise direction W). It should be noted that the disposable diaper  10  may be provided with waist gathers arranged in the front waistline units  20  and the back waistline unit  30  in the product widthwise direction W. 
     (2) Shape of Leg Hole Stretch Unit  100   
     Next, the shape of the leg hole stretch units  100  and the like are explained in details. As shown in  FIG. 2 , the leg hole stretch units  100  are formed in end edges of the leg hole concave units  35  of the disposable diaper  10 , respectively. As described above, the side edges in the product widthwise direction of the leg hole stretch units  100  meander in the product longitudinal direction L. Specifically, because of formation of inflection points P 1  to P 5  in the leg hole stretch unit  100 , the side edges in the product widthwise direction W of the leg hole stretch units  100  become a meandering shape. Therefore, each of side ends in the product widthwise direction of the leg hole stretch units  100  is convexo-concave in the product widthwise direction W with respect to a curved line  51  along the leg holes of a wearer of the disposable diaper  10 . 
     More specifically, a distance (distances d 1 , d 2 ) between each of side edges in the product widthwise direction W of the leg hole stretch units  100  and a center line CL (see  FIG. 1 ) as a straight line passing through the center in the product widthwise direction W and extending in parallel to the product longitudinal direction changes from the front waistline unit  20  to the back waistline unit  30 . The plural number of inflection points (inflection points P 2 , P 4 ) at which the amount of change in this distance shifts from increase to decrease and the plural number of inflection points (inflection points P 1 , P 3 , P 5 ) at which the amount of change in this distance shifts from decrease to increase are respectively provided. 
     Here, the distances are measured, when the disposable diaper  10  is in an open expanded condition. 
     A method of manufacturing the disposable diaper  10  includes at least a component-forming step, a component-loading step, a leg-hole-forming step, and a cutting step. In the component-forming step, components making up the disposable diaper  10  are formed. Specifically, for example, absorbent materials are laminated to form the absorber  40 , and after arranging a continuous band-shaped elastic member in a predetermined shape, the elastic member is cut into an individual product length to form a stretch sheet  200 . 
     In the component-loading step, on a web making up an exterior sheet, making up the disposable diaper are loaded, in which the components include, e.g., the stretch sheet  200 , other web such as a web configuring a topsheet  50 , a water-resistive sheet, and the absorber. 
     In the leg-hole-forming step, the topsheet  50  and the exterior sheet are cut along the concave units making up the leg hole regions outside the stretch sheet  200  in the product widthwise direction W. In this manner, the leg hole regions arranged along the legs of a wearer are formed. 
     In the cutting step, a continuous body in which the topsheet  50 , the exterior sheet, the absorber  40 , and the stretch sheet  200  are arranged is cut into a size of a single product in the product widthwise direction W. In this manner, the disposable diaper  10  is manufactured. 
     Furthermore, in the present embodiment, a width W 1  along the product widthwise direction W of the leg hole stretch units  100  in the natural state is preferably 5 mm to 45 mm, more preferably 12.5 m to 40 mm. It should be noted that the natural state means a case where the disposable diaper  10  is taken out of a package and kept in ambient atmosphere having a temperature of 20° C.±2° C., and a relative humidity of 60%±5% RH for 60 minutes, and then is measured. Furthermore, the ratio of expansion and contraction of the leg hole stretch units  100  is set to 1.5 times to 2.4 times. 
     Here, the width are measured, when the disposable diaper  10  is in an open expanded condition. 
     The ratio of expansion and contraction implies the extent of expansion and contraction of the leg hole stretch units  100  in the product widthwise direction W, and is stipulated as below: 
       Ratio of expansion and contraction=(Length of the leg hole stretch unit 100 of the product in the maximum extended state)/(Length of the leg hole stretch unit 100 of the product in the natural state) 
     The length in the maximum extended state is obtained by measuring a length in the product widthwise direction W of the leg hole stretch units  100  as a measuring object at the time when the product is extended at the maximum to an extent that the product is not destroyed, in the product (disposable diaper  10 ) provided with the leg hole stretch units  100  as a measuring object. Furthermore, the length in the natural state as a contracted state is obtained by measuring a length along the product widthwise direction W of the leg hole stretch units  100  in a state in which the product is placed on a flat surface while minimizing the convex and concave resulting from gathers with as little load as possible, the load being applied to cause extension in the product widthwise direction. In a case like the present embodiment, in which the leg hole stretch units  100  are curved, it is preferable that a length be measured in each of the above-described states along a line of an inner end in the product width direction W of the stretch sheet  200 . 
     Amplitude A in the product widthwise direction W at the meandering parts formed in the leg hole stretch units  100  is preferably 2.5 mm to 20 mm. In a case where a predetermined inflection point (for example, the inflection point P 3 ) is used as a reference, the amplitude A is a distance between this reference inflection point and a position which is perpendicular to a straight line passing through two inflection points (for example, the inflection points P 4 , P 5 ) adjacent to this reference inflection point and passes through this reference inflection point. It should be noted that a start point of an amplitude of a convex unit  110  is a position (E 1  shown in  FIGS. 1 and 2 ) of the intersection point between the center in the product longitudinal direction L of the target tape  65  and each of the side edges of the side flaps  70  while a start point of an amplitude of a convex unit  120  is a position (E 2  shown in  FIGS. 1 and 2 ) of a proximal end at the crotch unit  25  side of the fastening tape  90 . 
     Furthermore, the amplitude A is a distance between the aforementioned inflection point and position which are measured in the disposable diaper  10  in an expanded and extended state. In a case of the amplitude A less than 2.5 mm, convexo-concave regions cannot be formed enough in the leg hole stretch units  100 , thereby making it difficult to reduce the pressure on the skin at the time of wearing the disposable diaper  10 . Furthermore, the amplitude A greater than 20 mm tends to invite a situation in which the leg hole stretch unit  100  is sandwiched between the body of a wearer and the disposable diaper  10  in association with a movement of the wearer, so that each convexo-concave region cannot exhibit the effect of its function. Yet further, the convex and concave stand out too much, which makes a poor visual impression of the leg holes at the time of wearing the disposable diaper  10 . 
     The expanded and extended state implies a state in which the entire disposable diaper  10  is expanded as shown in  FIG. 1 . Specifically, the disposable diaper  10  can be put in such a state by extending a region of the gathers designed to be expanded and contracted with the use of elastic elements, to an extent that the gathers disappear visually, and retaining the disposable diaper  10  on a flat board. 
     Furthermore, the amplitude A can be also confirmed by taking only a non-stretchable member (in the present embodiment, the nonwoven fabric forming the side top or the backsheet) forming the leg hole units, out of the disposable diaper  10  main body. 
     The front and back ends of each leg hole concave unit  35  are provided with convex units  110 ,  120  which are convexed towards the outer side in the product widthwise direction W as compared to the other parts of the leg hole concave unit  35 . 
     Herein,  FIG. 4  is a diagram illustrating schematically a state in which the disposable diaper  10  is worn by a wearer. Since the front and back ends of the leg hole concave unit  35  are, because stress is likely to concentrate therein, preferably conditioned to achieve more distribution of the pressure on the skin by formation of the convex units  110 ,  120 . Specifically, since these are positioned close to the proximal ends of the fastening tapes  90  and the target tape  65  provided to the front waistline unit  20  while functioning as the front and back ends of the leg hole concave unit  35 , the stress is likely to concentrate therein, and these are also regions which are overlapped one after the other at the time of wearing the disposable diaper  10 , so that these ends are preferably convexed in order to distribute the pressure on the skin. 
     Further, a width W 2  in the product widthwise direction W and a length L 2  in the product longitudinal direction L of the convex unit  110  positioned closer to the front end of the leg hole concave unit  35  (or the convex unit  120  positioned closer to the back end of the leg hole concave unit  35 ) are preferably greater than a width in the product widthwise direction W and a length in the product longitudinal direction L of the convex unit  130  formed in the crotch unit  25 . The convex unit  130  and the concave unit  140  formed in the crotch unit  25  are required to be placed along the body of a wearer in addition to reducing the pressure on the skin. On the other hand, positions closer to the front end and the back end of the leg hole concave unit  35  are required to reduce more pressure on the skin. Accordingly, a shape like in the present embodiment can reduce the load itself on the leg hole stretch units  100  caused by a movement of a wearer while preventing the pressure on the skin from concentrating in a specific part. 
     Each of concave units  125  is concaved towards the center side in the product widthwise direction W so as to follow the curved line  51  along the leg hole of a wearer, thereby easily following the inguinal portion of the wearer. Accordingly, the stretch sheets  200  have a better fit into a wearer, thereby allowing the front waistline unit  20  to the crotch unit  25  of the disposable diaper  10  to stably follow the body regardless of a movement of the wearer. For example, even in a case where the legs of a wearer move so as to narrow a width of the absorber  40 , the concave unit  125  continues to fit into the inguinal unit, thereby enabling the absorber  40  to have a large width without narrowing it. Accordingly, it is preferable to have a concave unit like the concave unit  125  in a position closer to the front waistline unit  20  than the center in the product longitudinal direction L of the disposable diaper  10 . 
     Each of the convex units  130  is formed in a position corresponding to the crotch unit  25  of a wearer. The crotch unit  25  is sandwiched between the leg holes of a wearer and is a region having a narrow distance between the right and left leg holes, so that it is a part in which the leg hole stretch units  100  are prone to be wedged in the disposable diaper  10  by being sandwiched between the absorbent body  15  and the body of a wearer. Therefore, it is preferable that the body be covered by the leg hole stretch units  100  as widely as possible, and the convex unit  130  can further ensure to prevent the leakage of bodily waste from the absorbent body  15 . Furthermore, as described above, fitting of the concave unit  125  into the inguinal unit further prevents wedging of the convex unit  130 . 
     The concave units  140 ,  160  are formed closer to the back waistline unit  30  than the center in the product longitudinal direction L of the disposable diaper  10 . That is, the plurality of these concave units are formed closer to the back waistline unit  30  than the center in the product longitudinal direction L of the disposable diaper  10 . The concave unit  140  is formed adjacent to the center in the product longitudinal direction L of the disposable diaper  10 . The concave unit  160  is formed in the back waistline unit  30 . Furthermore, in the leg hole stretch units  100 , a part provided with the concave units  140 ,  160  has a smaller width in the product widthwise direction W than that of a part other than the concave units  140 ,  160 . Specifically, in the leg hole stretch units  100 , the part provided with the concave units  140 ,  160  has a smaller width in the product widthwise direction W than a width in the product widthwise direction W of the convex units  130 ,  150  or a width in a stretchable region (a width of a region designated as W 1  in  FIG. 2 ) at the outer end in the product widthwise direction W of the leg hole stretch units  100 . 
     Specifically, the concave units  140 ,  160  are formed so that the amount of change in a distance from the center line CL shifts from decrease to increase, more specifically, the concave units  140 ,  160  are formed so as to include the inflection points P 3 , P 5  at which the amount of change in a distance from the center line CL shifts from decrease to increase. 
     Each of convex units  150  convexed towards the outer side in the product widthwise direction W is formed between the concave units  140 ,  160 . That is, the convex units  140 ,  160  are formed at a predetermined interval in the product longitudinal direction L. Such a shape can prevent a situation that the leg hole stretch units  100  (or the leg side gathers  80 ) get stuck in the body of a wearer so the crotch unit cannot approach the crotch of a wearer and the disposable diaper is worn without covering the front waistline (abdominal portion) at the time of wearing the disposable diaper  10  to the body of a wearer with the use of the fastening tapes  90 . 
     The concave unit  160  is formed in order to prevent situations that the leg hole stretch units  100  at the back waistline unit  30  side get stuck in the body of a wearer and cannot be fixed in a proper position at the time when the fastening tapes  90  located at respective sides of the back waistline unit  30  are fixed to the target tape  65  and that the disposable diaper  10  is worn with the leg hole stretch units  100  at the back waistline unit  30  being projected from the fastening tapes  90 . If the leg hole stretch units  100  get stuck in the body of a wearer and the disposable diaper  10  is worn with the leg hole stretch units  100  being projected, a force is exerted in a direction of shifting the disposable diaper  10  downward in association with movement of the legs of a wearer, and the shifting is prone to occur even if the disposable diaper  10  is retained at the waistline with the use of the fastening tapes  90 , so that this is not preferable. 
     The convex unit  150  is formed, as well as the adjacent concave units  140 ,  160 , in order to reduce the pressure on the skin mainly in a position corresponding to the hip portion to a position corresponding to the back of wearer. Furthermore, the convex unit  150  covers the hip portion of a wearer widely to result in improvement of the appearance and at the same time, by covering the body widely, the convex unit  150  gives a sense of security that the leakage of bodily fluid or positional shifting of the disposable diaper  10  hardly occurs. 
     Furthermore, in the present embodiment, as shown in  FIG. 3 , in a position corresponding to the front waistline unit  20  and/or the crotch unit  25 , a thickness at the outer side in the product widthwise direction W of the leg hole stretch units  100  is preferably smaller than a thickness at the inner side in the product widthwise direction W of the leg hole stretch units  100 . Specifically, a thickness of each side edge in the product widthwise direction W of each of the leg hole stretch units  100  is made smaller than the inner side in the product widthwise direction W by decreasing the number of laminated sheets in a position closer to the each side edge. In the present embodiment, as shown in  FIG. 3 , three sheets (the leg side gather  80 , the stretch sheet  200 , and the back sheet  60 ) are provided in the side edge part (T 1  in  FIG. 3 ) in the product widthwise direction W of the leg hole stretch unit  100 . On the other hand, four sheets (with the addition of the leakage-preventing film  55 ) are provided in the inner part (T 2  in  FIG. 3 ) in the product widthwise direction W of the leg hole stretch unit  100 . 
     As described above, by forming each of the side edge parts in the product widthwise direction W of the leg hole stretch units  100  thinner than the inner side in the product widthwise direction W, the leg hole stretch units  100  are easily brought in close contact from the inner side towards the outer sides in the product widthwise direction W at the time of wearing the disposable diaper  10 . In a case where a thickness is made smaller as approaching to each of the side edge parts in the product widthwise direction W of the leg hole stretch units  100 , the leg hole stretch units  100  are easily brought in close contact with the skin, and especially by providing this thin part to a concave part of the body such as the inguinal portion of a wearer, the fitting property or stability of the leg hole stretch units  100  can be improved in the inguinal portion. At the same time, the hole stretch units  100  can exhibit the effect of distributing the pressure to the skin. Accordingly, the fitting property or stability of the leg hole stretch units  100  can be improved in the inguinal portion while a enabling the leg hole stretch units  100  to exhibit the effect of distributing the pressure to the skin. 
     Furthermore, the stretch sheet and non-stretchable sheet making up the leg hole stretch units  100  are joined together by means of pattern coating such as spiral coating or omega coating in which a linear adhesive is placed to have both of a part having an adhesive and a part having no adhesive. Furthermore, the stretch sheet is a nonwoven fabric sheet made from stretchable fabrics having elastomer property while the non-stretchable sheet is also a nonwoven fabric sheet. 
     That is, no film sheets exist in ends of the leg hole concave units  35 . With these configurations, the ends of the leg hole concave units  35  allow the nonwoven fabric sheets to entwine its fabrics each other, thereby staying unopened at the time of usage of the disposable diaper  10  and at the same time, the entire ends of the leg hole concave units  35  are free from an adhesive, thereby being able to make the leg hole stretch units  100  softer. 
     Furthermore, by means of coating described above, it is also possible to prevent stretchability of the stretchable sheet from being damaged by the non-stretchable sheet, thereby being able to enhance contact to the body of a wearer in the vicinity of the leg hole concave units  35 . 
     (3) Operation and Effect 
     As described above, each of the side edges in the product widthwise direction W of the leg hole stretch units  100  is in a meandering shape in the product longitudinal direction L, and a distance between each of the side edges in the product widthwise direction W of the leg hole stretch units  100  and the center line CL changes from the front waistline unit  20  to the back waistline unit  30 , and the plural number of inflection points at which the amount of change in this distance shifts from increase to decrease and the plural number of inflection at which the amount of change in this distance shifts from decrease to increase are respectively provided. 
     This prevents a situation that the leg hole stretch units  100  (or the leg side gathers  80 ) get stuck in the body of wearer and the disposable diaper  10  is worn without covering the front waistline (abdominal portion) at the time of wearing the disposable diaper  10  to the body of a wearer with the use of the fastening tapes  90 . As described above, the leg hole stretch units  100  (or the leg side gathers  80 ) hardly get stuck in the body of a wearer, so that the disposable diaper  10  can be worn while a position in which the fastening tapes  90  are engaged with the target tape  65  is placed even closer to the center in the product widthwise direction W, thereby being able to enhance contact to the waistline portion or the hip portion of a wearer. Furthermore, the leg hole stretch units  100  in a meandering shape distribute the pressure effectively even when they are brought in close contact with the skin of a wearer, so that the leg hole stretch units  100  can be prevented effectively from biting into the skin of a wearer, thereby being able to reduce the stimulation on the skin of a wearer. That is, according to the disposable diaper  10 , the stimulation on the skin in the vicinity of the leg hole units of a wearer can be further reduced while enhancing adhesion around the leg holes. 
     In a comparative test between the disposable diaper  10  and the conventional disposable diaper without having the leg hole stretch units  100  in a meandering shape, it has been confirmed that a wearing mark (skin redness) is prevented from occurring in, for example, the inguinal portion of a wearer while improving the fitting property into the leg holes. 
     Furthermore, in the leg hole stretch units  100 , the part provided with the concave units  140 ,  160  has a smaller width in the product widthwise direction W than that of the part other than the concave units  140 ,  160 , so that in the leg hole stretch units  100 , the part provided with the concave units  140 ,  160  is stretched out more than the part other than the concave units  140 ,  160 . In the leg hole stretch units  100 , the part stretched out more than the part other than the concave units  140 ,  160  is contracted more greatly, so that the concave units  140 ,  160  can be brought in even closer contact with the leg holes of a wearer. 
     (4) Other Embodiments 
     As described above, the present invention is disclosed through the above embodiments of the present invention. However, it should not be interpreted that the statements and drawings constituting a part of the present disclosure limit the present invention. From this disclosure, a variety of alternate embodiments, examples, and applicable techniques will become apparent to one skilled in the art. 
     For example, a shape of the leg hole stretch units  100  may be modified as follows.  FIG. 5  is an enlarged plan view of a leg hole stretch unit  100 A according to a modification of the present invention. As shown in  FIG. 5 , convex units  130 A,  150 A and a concave unit  140 A may be shaped smaller than the convex units  130 ,  150  and the concave unit  140  of the leg hole stretch unit  100 . That is, a value of the amplitude A of the leg hole stretch unit  100 A may be smaller than that of the leg hole stretch unit  100 . 
     In the above-described embodiment, as shown in  FIG. 3 , each of the stretch sheets  200  making up the leg hole stretch units  100  extends up to each outer end in the product widthwise direction W. However, the stretch sheet  200  may not necessarily extend up to the outer end in the product widthwise direction W in consideration of manufacturability and the like. That is, the outer end in the product widthwise direction W of the stretch sheet  200  may be positioned at the inner side in the product widthwise direction W with respect to the outer end in the product widthwise direction W of the backsheet  60 , the leg side gather  80 , or the like. In such a case, a distance between the outer end in the product widthwise direction W of the stretch sheet  200  and the outer end in the product widthwise direction W of the backsheet  60 , the leg side gather  80 , or the like is preferably less than 7 mm. 
     Furthermore, in the above-described embodiment, the open-type disposable diaper provided with the fastening tapes  90  has been described as an example. However, the present invention can also be applied to a pant-type disposable diaper. 
     As described above, needless to say, the present invention includes various embodiments and the like not described here. Therefore, the technical range of the present invention is to be defined only by the inventive specific matter according to the adequate claims from the above description. 
     REFERENCE SIGNS LIST 
     
         
           10  . . . Disposable diaper 
           15  . . . Absorbent body 
           20  . . . Front waistline unit 
           25  . . . Crotch unit 
           30  . . . Back waistline unit 
           35  . . . Leg hole concave unit 
           40  . . . Absorber 
           40   a  . . . Absorbent core 
           40   b  . . . Core wrap 
           50  . . . Topsheet 
           55  . . . Leakage-preventing film 
           60  . . . Backsheet 
           65  . . . Target tape 
           70  . . . Side flap 
           80  . . . Leg side gather 
           90  . . . Fastening tape 
           100 ,  100 A . . . Leg hole stretch unit 
           110 ,  120 ,  130 ,  130 A,  150 ,  150 A . . . Convex unit 
           125 ,  140 ,  140 A,  160  . . . Concave unit 
           200  . . . Stretch sheet