MXPA99001091A - Absorbent article - Google Patents

Abstract

This invention is an absorbent article including a first flap (100) extending laterally outward from longitudinal side edges (26) of a main body portion (22). A second flap (102) is offset to one of longitudinal end edges (28) of the absorbent article (22), and formed with a larger width than a transverse width of the main body portion (22) at which the first flap (100) is positioned. The first flap (100) is folded over along a side edge of a leg opening of a wearer's undergarment (200). The second flap (102) is maintained in a broadened condition within the wearer's undergarment (200). A joining part (104) is provided to connect the first flap (100) with the second flap (102) on the outside of the longitudinal side edges (26) of the main body portion (22). A zone of extensibility (116) is provided in a region of at least a portion of the joining part (104) where the side edge of the leg opening of the undergarment (200) is placed when the absorbent article is used.

Description

ABSORBENT ARTICLE FIELD OF THE INVENTION The present invention relates to an absorbent article such as a sanitary napkin, panty liner, or incontinence products of adults and the like. Still more particularly the present invention relates to an absorbent article such as a sanitary napkin, and the like, which is configured to have a portion of a flap folded under the wearer's undergarment.

BACKGROUND OF THE INVENTION Absorbent articles are available for use, particularly as a sanitary napkin having a wing or flap formed to be folded under the back of an undergarment along the lateral edges of the leg openings of the undergarment of the undergarment. user. A first type of sanitary napkin is disclosed in Japanese Laid-open Patent Publication S60-75058 (U.S. Patent 4,589,876), Japanese Laid-open Patent Publication S60-199446 (U.S. Patent 4,687,478), Japanese Patent open to the public H2-501710 (international publication WO 88/04546), and Japanese patent publication open to the public H5-505122 (international publication WO 91/14415). A sanitary napkin having a flap with an elastic portion along the total length of a longitudinal side portion is disclosed in Japanese Laid-Open Patent Publication H2-7956 (U.S. Patent 4,940,462). When this towel is used, the total flap is folded along the side edge of the leg opening of the undergarment.

A second type of sanitary napkins are disclosed in Japanese Patent Laid-Open Publications H2-168949, H4-128728, H7-33314. The sanitary napkin disclosed there, as prior art, has a front flap that bends during use along the lateral edges of the leg openings of the wearer's undergarment, a back flap that is provided in a position that it is longitudinally compressed toward the back of the sanitary napkin, and a narrow central part that is formed between these tabs. Although the first previously noted type of sanitary napkin has the effect of preventing leakage at the lateral edges of the leg openings of the undergarment, it does not provide sufficient prevention of leakage at the back of the sanitary napkin.

In the above-mentioned second type of sanitary napkin, when the sanitary napkin is used, the front flap is folded along the side edge of the leg openings of the undergarment, thus preventing staining of the side edge portion. of the undergarment. However, because the narrow central part does not protect the side edges of the undergarment, sufficient stain prevention is not provided for the portion of the lateral edges of the leg opening of the undergarment corresponding to the narrow central part. Therefore, the present invention has as an object to provide an absorbent article that allows an extension of the protected region of the lateral edges of the leg opening of the undergarment, when a part of a flap is folded backwards about the undergarment Another object of the present invention is to provide an absorbent article of which part of a flap can be extended when a part of a flap is folded backwards around the undergarment.

BRIEF DESCRIPTION OF THE INVENTION An absorbent article according to the present invention is an absorbent article comprising a main body portion, said main body portion comprising a surface facing the liquid-permeable body, and a surface facing the liquid impervious to the liquid, and an absorbent core placed between the surface facing the body and the surface facing the garment, the absorbent article comprising: a first flap extending laterally outwardly from the longitudinal side edges of the main body portion, said first flap being adapted to be folded backwards along the lateral edge of the leg opening of an undergarment of the wearer, and a second flap disposed in a position that is offset towards one of the longitudinal end edges of the absorbent article, the second flap being formed with a width greater than the transverse width of the main body portion in wherein the first flap is placed, said second flap is adapted to be maintained in a flared condition within the wearer's undergarment, a connecting part connecting the first flap with the second flap on the outer side of the longitudinal side edges of the main body portion, and a zone of extension capacity provided in a region of at least a part of the joining part where the side edge of the leg opening of the undergarment is placed when the absorbent article is used, said zone of extension capacity, which is provided in the joint part is extending to enclose the side edge in the leg opening of the undergarment when the first flap is folded backwards along the side edge of the leg opening of the undergarment. An absorbent article according to the present invention is preferably configured as follows: specifically, the joining portion may be a region that is enclosed between the first fin and the second fin in a longitudinal direction, said extensibility zone comprising a corrugated region, which is imparted to at least a part of the joining part. Said first fin and said second fin may comprise a region with smaller extension capacity than that of the zone of extension capacity. Said main body portion can be formed by a top sheet which is disposed on the surface facing the body, a back sheet which is disposed on the surface facing the garment, and an absorbent core being placed between them, said first fin, said second fin, and said joining portion being formed by a part of the backsheet, which is extending from at least the lateral edges of the absorbent core. Said extensibility can be formed by a corrugated region which is imparted to a part of the extended backsheet, and where there is no corrugated region imparted to the main parts of the first fin and the second fin, which are adjacent to each other. the corrugated region. The extensibility zone may have an extension capacity in at least one direction, and is extendable according to a pulling force which is applied to the joining part when the first fin is folded backwards along the lateral edge of the leg opening of the undergarment. An extension ratio of the extensibility zone may be 10% or greater, and is preferably 30% or greater. Additionally, an extension scale in the joining portion of the longitudinal side edges of the main body portion to the distant edges of the joining portion may be 10% or more of shorter extension ranges from the main body portion towards the distant edges of the first fin and the second fin. An extension range in the attachment portion from the longitudinal side edges of the main body portion to the distant edges in the extensibility zone is not greater than 140% of greater extension ranges from the main body portion to the distant edges. of the first fin and the second fin. Preferably, the extension range in the attachment portion from the longitudinal side edges of the main body portion to the distant edges of the extensibility zone may be 30% or more of the shorter extension ranges from the body portion main to the distant edges of the first fin and the second fin. Even more, the extension range in the joining portion from the longitudinal side edges of the main body portion to the distant edges of the extensibility zone may be no greater than 120% of the longer extension ranges of the main body portion towards the distant edges of the first fin and the second fin. Preferably, the extension range in the attachment portion from the longitudinal side edges of the main body portion to the distant edges of the extensibility zone may be approximately equal to the range of extension from the main body portion to the distant edges. of the first or second fin, and wherein a line connecting the far edges to each other may be closely parallel to the longitudinal side edges of the main body portion.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a top plan view of a sanitary napkin embodiment according to the present invention. Figure 2 is a cross-sectional view taken along the line ll-ll of Figure 1. Figure 3 is a cross-sectional view taken along the line of Figure 1. Figure 4 is a partially cut top plan view of another embodiment of the fin shape. Figure 5 is a top plan view partly cut away of another embodiment of the fin shape. Figure 6 is a top plan view partly cut away of another embodiment of the fin extension direction. Figure 7 is a top plan view partially cut away of yet another embodiment of the fin extension direction. Figure 8 is a simplified perspective view of an apparatus imparting extension capacity to a sanitary napkin according to the present invention. Figure 9 is an exploded partially enlarged view of an apparatus imparting extension capacity to a sanitary napkin according to the present invention. Figure 10 is a segmented cross-sectional view of an apparatus imparting extension capacity to a sanitary napkin according to the present invention. Figure 11 is a plan view cut in half showing the condition of a sanitary napkin according to the present invention placed in an undergarment. Figure 12 is a perspective view showing the condition of a sanitary tolla according to the present invention, placed in an undergarment. Figure 13 is a plan view as seen from the inside of an undergarment of the condition of a sanitary napkin according to the present invention, placed in an undergarment. Figure 14 is a plan view as seen from the outside of an undergarment of the condition of a sanitary napkin according to the present invention, placed in an undergarment. * DETAILED DESCRIPTION OF THE INVENTION A preferred embodiment of a sanitary napkin 20 according to the present invention is shown in Figure 1. As shown in Figure 1, the sanitary napkin 20 is basically formed by an absorbent means (i.e., a "main body portion"). ") 22, and two flaps 24. The sanitary napkin 20 has a body facing surface 20A and a garment facing surface 20B. The sanitary towel 20 is shown in Figure 1 to allow a view of the surface facing the body 20A. The surface facing the body 20A is arranged to be in close contact with the user's body, and the surface facing the garment 20B is arranged to be in close contact with the wearer's undergarment when the towel is in use. sanitary The sanitary napkin 20 has a longitudinal center line L and a transverse center line T. The term "longitudinal", as used herein, refers to a line, an axis or an address in the plane of the sanitary napkin 20, which It is aligned with a vertical plane that divides a user standing in left and right body halves when using the sanitary pad. The term "transverse", as used herein, refers to a line, an axis or an address that is located within the plane of the sanitary napkin 20, which is perpendicular to the longitudinal direction. As shown in Figure 1, the main body portion 22 of the sanitary napkin 20, comprises the portion of the sanitary napkin without flap 24. The main body portion 22 exactly matches the shape of the absorbent core 42, and has two. longitudinal side edges 26 arranged to have a spacing between them, and two transverse edges 28 arranged to have a spacing between them. The main body portion 22 also has two end regions that are designated as a first end region 32 and a second end region 34 and a central region 36 that is disposed between the end regions 32 and 34. The central region 36 further has a first central region 36A which is in close contact with the first extreme region 32, and a second central region 36B which is in close contact with the second end region 34. The main body portion 22 of the sanitary napkin 20 can be of any thickness, such as, for example, relatively thick, of medium thickness, relatively thin, or extremely thin. An ultrathin sanitary napkin 20 as noted in U.S. Patent 4,950,264 and U.S. Patent 5,009,653 issued to Osborn, preferably has a thickness of 3mm or less. The modality of a sanitary napkin 20 shown in the drawings is that of the example of a sanitary napkin having an average thickness. The main body portion 22 of the sanitary napkin 20 can be made relatively flexible, to avoid imparting a feeling of discomfort to the wearer. Figure 2 shows the individual components of the main body portion 22 of the sanitary napkin 20 according to the present invention. The main body portion of the sanitary napkin is preferably formed by at least 3 main elements. These include a liquid permeable top sheet 38. A liquid impermeable backsheet 40 and an absorbent core 42 which is placed between the topsheet 38 and the backsheet 40. The topsheet, the backsheet and the absorbent core can be assembled using a widely known method. There are a number of preferred materials to be used as the elements of the main body portion 22 of the sanitary napkin 20, and forms of assemblies of these elements, these being disclosed in U.S. Patent 4,321,924"Bordered Absorbent Article" , issued to Ahr on March 30, 1982; U.S. Patent 4,425,130"Composite sanitary towel" issued to Des Marais on January 10, 1984; U.S. Patent 4,950,264, "Thin, flexible sanitary towel", issued to Osborn on April 21, 1990; U.S. Patent 5,308,346"Elastic sanitary towel" issued Sneller et al. on May 3, 1994 and U.S. Patent 5,389,094"Absorbing article having fins and zones of differential extension capacity", issued to Lavash et al. February 1995. The main body portion 22 of the sanitary napkin 20, as disclosed in WO 93/01785 or WO 93/01786, may also be comprised of a combination of one or more extensible elements. Figures 1 to 3 show a preferred embodiment of the sanitary napkin 20 which is an example in which an upper and a rear sheet 40 have length and width dimensions which are both larger than those of the absorbent core 42 keeping the absorbent core 42 between they. The topsheet 38 and the backsheet 40 extend beyond part of the edge of the absorbent core 42. The topsheet 38 is preferably connected to the surface facing the body of the absorbent core 42, and the backsheet 40 is preferably connects to the garment facing surface of the absorbent core 42. The topsheet 38 and the backsheet 40 are connected to the absorbent core 42 by a widely known means, such as by adhesive attachment using an adhesive. The portions of the upper sheet 38 and of the rear sheet 40 that extend beyond the edge of the absorbent core 42 are also mutually connected. The top sheet 38 and the back sheet 40 are connected by a widely known method. Preferably, in the embodiment shown in the drawings, the parts of the topsheet 38 and of the backsheet 40 extending beyond the edge of the absorbent core 42 are connected by means of an adhesive, over substantially the total parts that are extend beyond the edges of the absorbent core 42. The transverse edge 28 of the main body portion is sealed to the top sheet 38 to the backsheet 40 by the application of pressure and heat.

The sanitary napkin 20 shown in Figures 1 to 3, as described above, further has a pair of fins 24 that are connected to the main body portion 22. The vanes 24 have proximal edges 44 disposed on the longitudinal side edges. 26 of the main body portion 22 and distant edges 46 disposed transversely outward from the proximal edges 44, and extending transversely outwardly from these proximal edges 44 towards these distant edges 46. As shown by the broken double dot line in Figure 1, the proximal edge 44 of the flap 24 may be approximately a straight line along the lateral edge 26 of the main body portion 22. The proximal edge of the flap 24 may be formed in a straight line of this way, but is not limited in this manner, and may also be in the form of a curved line that is not parallel to the lateral edge 26 of the body portion. or main 22, and in case the side edge of the main body portion 22 is a curve, it may be a curve that is parallel to it. The distal edge 46 is a straight line that is parallel to the proximal edge 44. The fin 24 is configured to extend continuously in the longitudinal direction, along the second end region 34 and the central region 36 of the main body portion 22, and to extend transversely outward from the longitudinal side edge 26 in those regions. As shown in Figure 1, each of these fins 24 has a first fin portion 100 extending from the first central region 36A of the main body portion 22, a second fin portion 102 extending from the end region. 34 of the main body portion 22, and a connecting flap portion 104 extending from the second central region 36B of the main body portion 22. The first flap 100 is arranged to be offset in the longitudinal forward direction of the body. the sanitary napkin (upwards in Figure 1), and is used by bending it upside down along a side edge of a leg opening of the undergarment when the sanitary napkin is used. The second flap 102 is arranged to be offset in the longitudinal back direction of the sanitary napkin 20 (downwardly in Figure 1) and keeps its flared condition within the undergarment when the sanitary napkin 20 is used. Additionally, the transverse width between the second fins 102 is established as being wider than that of the main body portion 22 that is sandwiched between the first fins 100. By doing so, in the crotch area of the undergarment, the first flap is folded backwards from the undergarment, thus protecting the lateral edge of the leg opening of the undergarment. In addition, on the back of the undergarment that is at the back of the crotch area, the second flap, which is formed to be wide, widens within the undergarment, thereby increasing the protective effect on the back . The attachment flap 104 connects the first flap 100 and the second flap 102, each of which extends from the main body portion 22, in the longitudinal direction. In the example illustrated in the drawings, the extension ranges of the first fin 100 and the second fin 102 from the proximal edge 44 are the same. The range of extension of the connecting flap 104 that connects to these fins is also the same. By doing so, the distal ends of the first flap 100, the second flap 102 and the attachment flap 104, are connected in a straight line, and are parallel with the proximal edge 44, respectively. However, the distant edges of each fin do not need to be parallel to the respective proximal edge 44, this is possible so that they are straight lines not parallel to the proximal edge 44, curved lines, or in a staggered way. For example, as shown in Figure 4 in the case in which the range of extension of the fin 24 of the near shore 44 gradually increases from the first fin 100 towards the second fin 102, the distant shore 46 of the fin 24 is a straight line (the solid line of Figure 4), which is inclined to increase in distance from the proximal edge 44 along the forward direction of the second fin 102. On the other hand, in the case in which the range of extension decreases gradually from the first fin 100 to the second fin 102, the distant edge 46 of the fin 24 is a straight line (dotted line in Figure 4), which is inclined to decrease in distance from the next shore 44 along the direction towards the second flap 102. Furthermore, as shown in Figure 5 it is possible that the distant edges 106, 108 and 110, of each flap are configured in the form of steps. In the illustrated example, the range of extension of each flap increases in the sequences of the attachment flap 104, the first flap 100, the second flap 102. Therefore, the distant edge 46 of the flap 24 is in the form of steps, which is closest to the connecting flap 104 part to the proximal edge 44. Additionally, because the extension range of the connecting flap 104 is maximum, as shown by the dotted line in Figure 5, the edge Distant 46 of the fin 24 is in the form of steps, with the attachment flap 104 farthest part of the proximal edge 44. The extension range from the proximal edge to the distal edge of the attachment flap 104 may be approximately determined . However, if this range of extension is too small when the first flap 100 is folded backwards it can not provide sufficient protection around the leg opening of the undergarment. If the extension range is too large, it becomes difficult to place the joint flap on the undergarment. Therefore, the value S of the extension range of the joining flap is not limited by this, but is preferably determined as follows. Specifically, the lower limit of the extension range S is preferably 10% or more of the smaller value of the extension range P of the first fin 100 and the extension range Q of the second fin 102. It is more preferable that this be of 30% or more thereof. The upper limit of the range of extension S is preferably not greater than 140% of the larger range of extension P of the first fin 100 and the extension range Q of the second fin 102. It is more preferable that it is not greater than 120% of the same. The fin 24 is attached to the main body portion 22 by various methods. The "joining" method, as used herein, encompasses configurations in which a given element is mounted directly to another element, configurations in which a given element is mounted to another element with an intermediate element between them, and configurations in which a given element is formed as one of another element (for example, the case in which elements are parts of other elements). Preferably, in the embodiment shown in Figures 1 to 3, the flap 24 is part of the main body portion 22. That is, the flap 24 is configured as the extending part of the top sheet 38 and the back sheet 40. In another embodiment, the flap 24 can be formed from one or more elements that are joined to the garment facing surface of the main body portion 22. For example, the flaps on both side edges of the body portion can be formed from separate elements, which are attached to the garment facing surface of the main body portion 22. In this type of embodiment, it is preferable that the fin 24 is not attached to the surface that it gives towards the garment of the main body portion of the sanitary napkin, between the portion of the main body portion to which the fin is attached and the longitudinal edge of the main body portion. In an example such as this, it is possible to use an appropriate method to attach the flap to the garment facing surface of the main body portion. An example would be that of fixing it adhesively with the use of adhesives, and the like. The flap 24 is attached to the main body portion 22 along a joining portion. This is typically a joining part in the longitudinal direction. The term "joining portion" (or "attachment lines") used herein means a region that, as it is, extends from or is in contact with the main body portion 22. This region is limited to being a line, and may be several curves or a straight line In the embodiment shown in Figure 1, the joint line may be treated as coincident with the proximal edge of the fin 24. The sanitary napkin 20, as shown in Figure 1, has an extensible region 116 in part of the flap 24. This extendable portion 116 is a region that has become extensible by mechanical deformation, as will be described below In the drawings showing this embodiment, the extensible region 116 that has been mechanically deformed is shown by a collection of lines In the embodiment shown in Figure 1, the extendable region 116 is formed as the boundary of the region by the curve 114, which defines the outer side in the direction cross section, the curve 112 defining the interior side in the transverse direction and the line defining the exterior of the sanitary napkin. Curve 114 coincides with the semicircular portion of intermediate region 118 which is approximately one half circle transversely outwardly of first fin 100. Curve 112, at the front of sanitary napkin 20 (upper part in Figure 1) , curves close to the proximal edge 44 of the fin 24 and is closer to the proximal edge 44 in part of the first fin 100. Curve 112, in the back of the sanitary napkin, bottom in Figure 1, curves to increase in distance away from the proximal edge 44 towards the distant shore 46. The expandable region 116 is further comprising a forward extensible region 120, a central extensible region 54 and a rear extensible region 122. The main part of the rear extensible region 122 is disposed within the joining flap 104. Part of the rear extendable region 122 extends to be adjacent to the central extendable region 54 that is placed close to the proximal edge of the first fin 100. The shape of the rear extensible region 122 is not limited to that shown in the illustrated embodiment. In this way, when the sanitary napkin 20 is used, it is sufficient to have an extensible region in the region of the attachment flap 104, in which an elastic element of the undergarment is disposed. In addition, in the illustrated modality, the sanitary napkin has a front expandable region 120 which is offset towards the front part of the first flap 100 (upper part in Figure 1). Referring now to Figure 1, at the fin 24 the regions that are not subject to mechanical deformation are the approximately semi-circular intermediate regions 118 of the fin 100, the main part of the second fin 102, and a side portion of the proximal edge 44 of the joining flap that is adjacent to it. Because the intermediate region 118 is not subjected to mechanical deformation, it is more rigid than the region that undergoes mechanical deformation. Because of this hardness, when the first flap 100 is folded backwards from the undergarment, it is easy for it to handle the first flap 100 and to perform the task of folding the first flap 100 backwards. Because the main part of the second flap 102, is also not subjected to mechanical deformation and is hard, its tendency to maintain its enlarged condition within the undergarment is increased. The shape of the region of the fin 24 that is subjected to mechanical deformation (e.g., the intermediate region 118) is not limited to the shape in the previously noted embodiment and may also be in some other form. It is possible to have the first fin 100 and part, and all or the main part of the second fin 102 which is an extensible region that is subjected to mechanical deformation. The rear extendable region 122 is extendable in the direction indicated by the arrows marked with X in Figure 1. In the illustrated embodiment, the extension direction X of the rear extendable region 122 is inclined at an angle of 45 degrees with respect to the cross-sectional line of the sanitary napkin 20. In this description the "slant" angle is taken to be 0 degrees in a direction that is parallel to the transverse center line T of the sanitary napkin 20, and is taken to be 90 degrees in a direction that is parallel to the longitudinal center line L of the sanitary napkin 20. In Figure 1, the "tilt" angle of the flap that is disposed on the right side of the longitudinal centerline L is taken so that it is positive (+) if a straight line indicating the direction is higher on the right, and negative (-) if the straight line indicating the direction is smaller on the right side. In Figure 1, the "tilt" angle of the fin 24 that is disposed on the left side of the longitudinal centerline is taken to be positive (+) if a straight line indicating the upper direction on the left side, and negative (-) if the straight line indicating the direction is smaller on the left side. Therefore, the extension direction X noted earlier in Figure 1 is at an angle of inclination of + 45 degrees. The extension direction X of the rear extendable region 122 must be greater than zero degrees and must not be greater than +90 degrees, which includes the +45 degrees previously noted (i.e., 0 degrees < inclination angle < +90 degrees). Figure 6 shows the case in which the extension direction X of the rear extensible region 122 is +90 degrees. The direction angle of the extension direction X is within a range of angles defined in this manner, such that with respect to the tension force generated in the attachment flap 104 when the first flap 100 is folded backwards, the extension of the joining flap 104 in an appropriate direction acts to moderate the pulling force. In addition, the angle of the extension direction X is preferably such that +45 degrees < = inclination angle < = + 90 degrees. The forward expandable region 120 has an extensibility in the direction indicated by the arrows marked Y in Figure 1. In the illustrated embodiment, the extension direction Y of the forward expandable region 120 is parallel to the transverse central line T of the towel Sanitary 20, which is zero degrees. The extension direction Y of the forward expandable region 120 is not limited to what is in this mode, and may not be greater than zero degrees, and -90 degrees or greater (0 degrees >.; = tilt angle > = -90 degrees), which includes the case of -45 degrees for the extension direction Y of the forward extensible region 120 shown in the example of Figure 7. Because the extension direction Y of the extensible region 120 is also within of an angle scale defined in this way, with respect to the generated tractive force, in the front part of the first flap 100 when the first flap 100 is folded upside down the front part of the first flap 10 extends in an appropriate direction to moderate the pulling force. In addition the angle of the extension direction Y is preferably such that -45 degrees > = inclination angle > = -90 degrees. The direction of extension of the central expandable region 54 is a direction in Figure 1 which is parallel to the transverse center line T of the sanitary napkin 20, which is zero degrees. However, there is no imposed limit in the extension direction of the central extensible region 54. The extensible region 54 in the illustrated embodiment has three non-deformed regions 55 along the vertical direction that are not subject to mechanical deformation. In the illustrated embodiment the front undeformed region 55 (at the top in Figure 1) defines the edge line for the forward extensible region 20, and the posterior non-deformed region (at the bottom in Figure 1) defines the edge line for the rear extensible region 122. Because the non-deformed regions 55 as they are subject to mechanical deformation this is hard, compared to the extensible region 116. For this reason, the region near the proximal edge of the first fin 100 is relatively difficult to bend. Therefore, the first flap 100 does not bend in an unexpected manner. Although undeformed regions 55 are provided in this embodiment, it is also possible to omit these non-deformed regions 55. It is further possible to have one or two undeformed regions and have four or more non-deformed regions. The preferred extension ratio of the posterior extensible region 122 of the present invention is 10% or more. In the case where the extension ratio of the rear extension region 122 is less than 10% the rear extension region 122 does not extend sufficiently with respect to the tension that is generated when the first wing 100 is folded under the garment inside. Therefore, this pulling force can change the trajectory of the elastic element in the undergarment, or act to pull on yet the main body part 22, this resulting in the bulge (of the main body portion). On the other hand, if this is greater than 10%, the rear expandable region 122 extends sufficiently in response to the pulling force. There is therefore little danger of the trajectory of the elastic element changing in the undergarment, and it is possible to enclose or appropriately surround the portion of the elastic element of the undergarment. In addition, because there is little traction on the main body portion 22, it is difficult for the main body portion 22 to exhibit bulging. Additionally, it is preferable that the extension ratio of the posterior extensible region 122 be 30% or greater, and preferably also that it be 50% or greater. The forward expandable region 120 and the central expandable region 54 can be made to have the same type of extension relationship. The extensible region 116 of the sanitary napkin described above can be formed by a variety of methods that impart a high degree of flexibility to the desired region of the sanitary napkin 20. The spreadable region 116 is preferably formed by mechanical deformation of a pre-written region. of the sanitary napkin 20. The spreadable region 116 can be formed by a method known as ring rolling. A preferred method of ring rolling is disclosed in the United States Patent 4, 107,364 issued to Sisson on August 15, 1978, United States Patent 4,834,741 issued to Sabee on May 30, 1989, United States Patent 5,143,679 issued to Gerald M. Weber et al. On September 1, 1992, patent No. 5,156,793 issued to Kenneth B. Buell et al. on October 20, 1992 and United States Patent 5,167,897 issued to Gerald M. Weber et al. on December 1, 1992. As shown in Figure 8, a Extendable region 116 is formed in sanitary napkin 20 by passing it through an apparatus imparting corrugations 300, such that the prescribed region is subjected to a mechanical deformation of corrugation. The corrugation imparting apparatus 300 has an upper roller 302 and a lower roller 304. The upper roller 302 comprises a pair of wheels 306 each having a peripheral surface that partially protrudes. For the purpose of imparting a corrugated shape to the fin 24 to form the expandable region 116 of the sanitary napkin 20, the surface projecting from the wheels 306 has a plurality of teeth 308 provided thereon. In Figure 8, the teeth 308 are hidden in the back of the wheel 306. The shape of the tooth 308 is shown in Figures 9. Figure 9 shows a flat development of the pattern of the teeth 308 which are cut in the wheel 306. As is clear from Figure 9, the pattern of the teeth 308 that are cut in one of the wheels 306 coincides with the shape of the extensible region 116 that is imparted to one of the fins 24 of the sanitary napkin 20. The surface of the other wheel 306 has a pattern (not shown in the drawings), which is symmetrical with respect to the pattern shown in Figure 9. The lower roller surface 304 has a pattern of teeth 310 that mesh with the pattern of the upper roller 308 teeth 302 (refer to FIG. 10). The wheels 306 are mounted on a roller 302 at a gap for placing them on the two fins 24 of the sanitary napkin 20. The lower roller teeth 310 are shown on the roller 304 to mesh with the upper roller teeth 308. Additionally , as shown in Figure 10, the wheels 306 have an upper contact piece 314, and a corrugated lower roller 304 have a lower contact piece 316. These contact pieces 314 and 316 make contact with one another, allowing the maintenance of a constant amount of engagement between the teeth 308 and the teeth 310. By adjusting this amount of contact, it is possible to impart a desired extension relationship to the workpiece. A sanitary napkin 20 is fed to a corrugation imparting apparatus 300 having the configuration as described above, in the direction shown by the arrow in Figure 8. Part of the vane 24 is passed between the wheels 306 and the lower roller 304. When this happens, a laminate 312 comprising an upper sheet 38 and a rear sheet 40 is mechanically deformed by the upper and lower teeth 308 and 310, such that the laminate 312 has permanent corrugations as shown in Figure 10. The extension capacity for the degree that the corrugation forms on the surface thereof, which can be flattened, is imparted to the laminate 312 (the fin 24) having the corrugation deformations. Because the corrugation forms are imparted in a direction that is perpendicular to the direction in which the teeth 308 and 310 extend (the direction in which the protruding and falling portions of the teeth 308 and 310 extend). The extensibility that is imparted is in the direction that is perpendicular to the direction in which the teeth 308 and 310 extend. By changing the direction in which the teeth 308 and 310 extend, it is possible to obtain the directions of extension of the regions. with extension capacity 122, 54, and 120, described above. As described above in this embodiment, the extensible region 116 is expressed as a set of lines. These lines show the permanently formed corrugated hills and valleys of the extensible region 116. Next, the condition of a sanitary napkin according to the present invention when it is fixed will be described, with reference being made to figures 11 to 14. In Figure 11, the sanitary napkin 20 is located within the undergarment 200 such that the elastic element 202 which is fixed to the lateral edge of the leg opening of the undergarment 200 is placed in the extensible region 116 of the flap 24. As shown in Figure 12, the first flap 100 is folded backwards along the elastic element 202. When the first flap 100 is folded backwards, the attachment flap 104 is also folded backwards to enclose the flap. elastic element 202. Therefore, compared to a sanitary napkin of the past, which does not have a binding flap, it is possible to widen the protected area in the lateral flaps of the leg openings of the undergarment 200. In Figure 12, and in Figure 13, the widened protected area of the binding flap 104 is indicated by the flap S. When the first flap 100 is folded in reverse, a pulling force is applied to the flap. fin 24 in the direction of the arrow shown in Figure 11. However, the various extensor regions of flap 24 have the extension directions and extension ratios described above. Therefore, by folding the first flap 100 backwards, there is no danger of changing the trajectory of the elastic element 202 of the undergarment, and it is possible to appropriately enclose the elastic element 202 of the undergarment. In addition, because there is little traction in the main body portion 22, it is difficult for the main body portion 22 to exhibit bulging (referred to in Figures 13 and 14). The surface facing the garment of the sanitary napkin includes means for attaching the sanitary napkin to the wearer's undergarment. Figure 1 shows a central fastening means 80 provided for the purpose of securing the main body portion 22 of the sanitary napkin to the crotch region of an undergarment. It is possible to use a means known as this fastening means. For example, it is possible to use a layer of adhesive or a mechanical fastener. The fastening means having an adhesive layer have been found to work well for this purpose, with a pressure sensitive adhesive being preferred. Figure 1 shows an example using a pair of strips or adhesive layers 80 longitudinally oriented, spaced apart, which are centered around the longitudinal centerline L. The outer surfaces of the intermediate regions 118 of the first fins 100 are provided with layers of adhesive of the first flap 82. After the adhesive layers of the first flap 82 are folded backwards around the lateral edges of the leg opening of the undergarment, they are used to hold the first flaps in place. fins. An example of an appropriate adhesive layer is described in greater detail in U.S. Patent 4,917,697. In addition, the external surfaces of the second fins 110 are provided with second fin adhesive layers 83. These second fin adhesive layers are provided. 83 are used to help keep them in a widened condition within the undergarment. These layers of adhesive can be the same, like the first fin adhesive layers 82. The adhesive layers are protected by a release liner of the central fastening means and fin release liner indicated as 84. These release liners 84 prevent the adhesive layers from being applied. in contact with other parts before being used. A suitable separable liner is disclosed in U.S. Patent 4,917,697. A release liner that is preferable for use as an individual package to maintain the sanitary napkin itself is disclosed in U.S. Patent 4,556,146 issued to Swanson et al. Although particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention.

Claims (13)

1. - An absorbent article comprising a main body portion, said main body portion comprising a surface facing the liquid permeable body, a surface facing the liquid impervious to the liquid, and an absorbent core positioned between the surface that gives towards the body and the surface facing the garment, the absorbent article comprising: a first flap extending laterally outwardly from the longitudinal side edges of the main body portion, said first flap being adapted to be folded backwards along the side edge of a leg opening of an undergarment of the wearer, a second flap disposed in a position that is offset towards one of the extreme longitudinal edges of the absorbent article, the second flap being formed with a greater width that the transverse width of the main body portion in which the first fin is placed, d The second flap is adapted to be maintained in a flared condition within the wearer's undergarment, a joining portion connecting the first flap with the second flap on the outside of the longitudinal side edges of the main body portion and, a zone of extensibility provided in a region of at least a portion of said joining portion wherein the side edge of the leg opening of an undergarment is placed when the absorbent article is used, said zone of extensibility, which is provided in the joint part, is extending to enclose the side edge of the leg opening of the undergarment when the first flap is folded backwards along the side edge of the leg opening of the undergarment.

2. - The absorbent article according to claim 1, wherein the joining part is a region that is enclosed and between the first fin and the second fin in a longitudinal direction, the extensibility zone comprising a corrugated region that is imparted to at least a part of the joining part.

3. The absorbent article according to claim 2, wherein the first fin and the second fin comprise a region with a smaller extension capacity than that of said extensibility zone.

4. The absorbent article according to claim 3, wherein the main body portion is formed by a top sheet that is disposed on the surface that faces the body, a back sheet that is arranged on the surface facing towards the body. the garment, and an absorbent core that is placed between them, said first fin, said second fin, and said joint part being formed by a part of the back sheet, which is extending from at least the lateral edges of said core absorbent.

5. The absorbent article according to claim 4, wherein the zone of extensibility is formed by a corrugated region, which is imparted to a part of the rear sheet that extends and where the uncorrugated region is imparted to. Main parts of the first fin and the second fin, which are adjacent to the corrugated region.

6. The absorbent article according to claim 1, wherein the zone of extensibility has an extension capacity of at least one direction, and is extended according to a pulling force that is applied to the joint part when the first flap is folded backwards along the side edge of the leg opening of the undergarment.

7. The absorbent article according to claim 6, wherein an extension ratio of the extensibility zone is 10% or more.

8. The absorbent article in accordance with claim 6, wherein the extension ratio of the extensibility zone is 30% or more.

9. The absorbent article according to claim 1, wherein a range of extension at the junction portion from the lateral and longitudinal edges of the main body portion to the distant edges of the junction portion of 10% or more of a smaller extent ranges from the main body portion towards the distant edges of the first fin and the second fin. The absorbent article according to claim 9, wherein an extension range in the attachment portion from the longitudinal side edges of the main body portion to the distant edges of the extensibility zone is not greater than 140% ranges of extension greater than the main body portion to the distant edges of the first fin and the second fin. 11. The absorbent article according to claim 10, wherein the extension range in the joining portion from the longitudinal side edges of the main body portion towards the distant edges of the extensibility zone is 30% or more. more than the shortest of the extension ranges from the main body portion to the distant edges of the first fin and the second fin. 12. The absorbent article according to claim 11, wherein the extension range in the joining part from the longitudinal side edges of the - main body portion towards the distant edges of the extensibility zone is not greater than 120% of the longest of the extension ranges from the main body portion to the distant edges of the first fin and second fin. 13. The absorbent article according to claim 12, wherein the extension range in the joining portion from the longitudinal side edges of the main body portion to the distant edges of the extensibility zone is approximately equal to the range of extension from the main body portion towards the distant edges of the first fin or the second fin, and wherein, a line connecting the distant edges to each other is approximately parallel to the longitudinal lateral edges of the main body portion.