Patent Publication Number: US-8114236-B2

Title: Method for making disposable pants-type diaper

Description:
RELATED APPLICATIONS 
     The present application is based on International Application Number PCT/JP2007/072303, filed Nov. 16, 2007 and claims priority from, Japanese Application Number 2007-005151, filed Jan. 12, 2007, the disclosures of which are hereby incorporated by reference herein in their entirety. 
     TECHNICAL FIELD 
     The present invention relates generally to a method for making a disposable pants-type diaper and particularly to a method for making such pants-type diaper adapted to prevent feces from coming in contact with the wearer&#39;s skin. 
     RELATED ART 
     There have conventionally been proposed various disposable diapers provided with the functions to protect the wearer&#39;s skin being soiled with feces which would otherwise come in contact therewith. For example, the pants-type diaper disclosed in PATENT DOCUMENT 1 includes the skin-contact sheet disposed on the inner sheet and is formed in the crotch region of this skin-contact sheet with the opening surrounded by the elastic member attached under tension to the inner sheet. This opening may be aligned with the wearer&#39;s anus to ensure that feces discharged by the wearer moves through the opening into the spaced defined below the skin contact sheet so that feces would not come in contact with the skin. In the case of the method for making the disposable pants-type diaper disclosed in PATENT DOCUMENT 2, the disposable pants having the opening formed in the inner sheet of the diaper is continuously made.
     PATENT DOCUMENT 1: JP 2002-11044 A   PATENT DOCUMENT 2: JP 1993-42180 A   

     DISCLOSURE OF THE INVENTION 
     Problems to be Solved by the Invention 
     However, the diaper disclosed in PATENT DOCUMENT 1 still has a problem that feces might move into a space defined between the wearer&#39;s skin and the skin-contact sheet and seriously soil the wearer&#39; skin unless the opening formed in the skin-contact sheet is exactly aligned with the wearer&#39;s anus. In other words, it is essential for this diaper of prior art to being the opening of the skin-contact sheet in alignment with the wearer&#39;s anus in the course of putting the diaper on the wearer&#39;s body. However, it can not be determined from the exterior whether the opening of the diaper having been put on the wearer&#39;s body is exactly in alignment with the anus or not. Furthermore, the skin-contact sheet is formed with a notch through which urine can be directly absorbed by the absorbent core. Regrettably, urine having passed through the notch will be inevitably mixed with feces on the surface of the absorbent core. Liquidity of feces will increase when it is mixed with urine and consequently a possibility that the wearer&#39;s skin might be soiled with feces will correspondingly increase. 
     In view of the problem left behind unsolved by the conventional diaper as has been described above, it is an object of the present invention to provide a novel disposable pants-type diaper improved to facilitate the wearer&#39;s anus to be exactly positioned in opposition to the opening of the feces receiving pocket and thereby to protect the wearer&#39;s skin from being soiled with feces. 
     Measure to Solve the Problem 
     The object set forth above is achieved, according to the present invention, by an improvement in a method for making a disposable pants-type diaper comprising the continuous steps of preparing a chassis having a crotch region having a back-and-forth direction and a transverse direction which is orthogonal to the back-and-forth direction, a front waist region extending forward from the crotch region and a rear waist region extending rearward from the crotch region wherein transversely opposite side edges of the crotch region extend in the back-and-forth direction, folding back the chassis about the crotch region in the back-and-forth direction, bonding respective inner surfaces of the front and rear waist regions put flat together to each other along transversely opposite side edges of the front and rear waist regions to make the chassis in pants-shape and providing the chassis on its inner surface with a sheet piece forming on the inner surface in the crotch region a pocket adapted to receive body waste. These continuous steps for making the disposable pants-type diaper further comprise the steps as will be described below. 
     The method according to the present invention further comprises steps of: 
     a) continuously feeding a first web in a machine direction wherein the first web having a dimension in a cross direction orthogonal to the machine direction bisected by a first center line is adapted to provide successively a plurality of the chassis each having the transverse direction in coincidence with the machine direction as the first web is cut at regular pitches in the machine direction, 
     b) continuously feeding a second web in the machine direction wherein the second web comprising a plurality of the sheet members contiguous one to another in the transverse direction, 
     c) folding the second web back onto itself along a first folding guide line defined by a second center line bisecting the cross direction and locally bonding respective halves of the second web thus folded back to each other along respective edges thereof at same pitches as the pitches so as to obtain a third web having these locally seal regions, 
     d) superposing the first web and the third web upon each other so that the first center line falls in with the first folding guide line formed by the third web in the step c) and the seal regions of the third web fall in with middle regions of the respective chassis, 
     e) locally bonding the third web to the first web in regions thereof destined to form transversely opposite side edges of the crotch region in the chassis or in regions located aside toward the middle regions of respective the chassis as viewed in the machine direction so as to obtain a first composite web having the third web spaced from the regions of the first web destined to define the chassis between the regions in which the first web and the third web are bonded to each other, 
     f) folding back the first composite web along a second folding guide line defined by the first center line with the third web inside and locally bonding the first web to the third web in regions falling in with the regions in which said first web and said third web are bonded to each other in the step e) so as to obtain a second composite web having the third web spaced from regions of the first web destined to define the chassis between the regions in which the first web and the third web are bonded to each other, 
     g) clipping out a substantially semicircular web piece having a chord defined by the second folding guide line and an arc being convex in the cross direction from a region of the second composite web defined between each pair of the adjacent chassis so as to form side edges of the crotch region opposed to each other in the machine direction and thereby to obtain third composite web, 
     h) bonding opposite inner surfaces of the first web folded back onto itself in the third composite web to each other along respectively opposite side edges of the front and rear waist regions in each pair of adjacent the chassis so as to obtain a fourth composite web formed with a linear seal region extending the cross direction, and 
     i) cutting the fourth composite web along a cutting line extending in the cross direction at middle of the seal region as viewed in the machine direction to obtain individual the pants-type diapers successively. 
     According to one preferred embodiment of the invention, order of the step g) and the step h) is reversed, i.e., the opposite inner surfaces of the first web folded back onto itself in the third composite web are bonded so as to form the linear seal region extending the cross direction and then the web piece is clipped out from the second composite web. 
     According to another preferred embodiment of the invention, the second web comprises inelastic web fed in the machine direction provided along opposite side edges thereof extending in parallel to each other in the machine direction with elastic members extending in the machine direction and attached under tension thereto. 
     According to still another preferred embodiment of the invention, the second web is elastically stretchable and contractible in the machine direction and fed under tension in the machine direction. 
     According to yet another preferred embodiment of the invention, the first web and the third web are locally bonded in the middle region of the crotch region in the chassis as viewed in the back-and-forth direction. 
     EFFECT OF THE INVENTION 
     The method for making the disposable pants-type diaper according to the present invention is characterized in that the second web comprising the continuous sheet member adapted to form the pockets in the individual pants-type diapers is continuously fed under tension in the machine direction onto and superposed to the first web continuously fed in the machine direction so as to be continuously bonded thereto. Namely, the second web has no need for any portion having no contribution to the desired function of the pocket such as chucked margins used to tenter the pants-type diaper in the transverse direction. Consequentially, the second web can be economically used in the course of making the pants-type diaper. The second web is superposed on the first web after the second web has been folded back onto itself and these folded halves thereof have been bonded to each other in the middle region of the chassis as viewed in the transverse direction thereof. Consequentially, the presence of the first web would not make it difficult to bond the halves of the folded second web to each other. 
     Preferred embodiments such method for making the disposable pants-type diaper and effect provided by these preferred embodiments will be described below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partially cutaway perspective view of a pants-type diaper; 
         FIG. 2  is a plan view of the pants-type diaper developed in flattened state; 
         FIG. 3  is a sectional view taken along the line III-III in  FIG. 1 ; 
         FIG. 4  is a sectional view taken along the line IV-IV in  FIG. 3 ; 
         FIG. 5  is a diagram partially illustrating a process for making the pants-type diaper; 
         FIG. 6  is a diagram illustrating a step following up a step illustrated in  FIG. 5 ; 
         FIG. 7  is a diagram illustrating the step following up the step illustrated in  FIG. 6 ; 
         FIG. 8  is a diagram illustrating the step following up the step illustrated in  FIG. 7 ; and 
         FIG. 9  is a diagram illustrating an alternative embodiment of the step illustrated in  FIG. 8 . 
     
    
    
     IDENTIFICATION OF REFERENCE NUMERALS USED IN THE DRAWINGS 
     
         
           1  pants-type diaper 
           6  crotch region 
           7  front waist region 
           7   a  opposite side edge of front waist region 
           8  rear waist region 
           8   a  opposite side edge of rear waist region 
           9  seal region 
           10   a  chassis 
           12  leg-hole 
           13  periphery 
           20  sheet member (sheet piece) 
           20   a  pocket 
           201  first web 
           202  second web 
           203  third web 
           215  web piece 
           301  first composite web 
           302  second composite web 
           303  third composite web 
           304  fourth composite web 
         p first center line 
         q second center line 
         X transverse direction 
         Y back-and-forth direction 
       
    
     DESCRIPTION OF THE BEST MODE FOR WORKING OF THE INVENTION 
     Details of a method for making a disposable pants-type diaper will be more fully understood from the description given hereunder with reference to the accompanying drawings. 
       FIG. 1  is a partially cutaway perspective view showing a disposable pants-type diaper  1  obtained by a method according to the present invention for making the same as put on the wearer&#39;s body. The pants-type diaper  1  has a pants-shaped skin covering assembly  10  comprising a liquid-pervious inner sheet  2 , a liquid-impervious outer sheet  3  and a body fluid absorbent core  4  sandwiched between these two sheets  2 ,  3 . The skin covering assembly  10  is configured to define a crotch region  6 , a front waist region  7  extending forward from the crotch region  6  and a rear waist region  8  extending rearward from the crotch region  6 . The front and rear waist regions  7 ,  8  are put flat together along respective laterally opposite edges  7   a ,  8   a  of thereof and sealed together along these laterally opposite edges in the belt-like seal region  9  in which a plurality of seal stripes  9   a  are arranged intermittently in a vertical direction as viewed in  FIG. 1  so as to form a waist-hole  11  and a pair of leg-holes  12 . Sandwiched between the inner and outer sheets  2 ,  3 , a plurality of waist elastic members  14   a ,  14   b  circumferentially extend along a periphery defining the waist-hole  11   a  and are bonded under tension to at least one of the inner and outer sheets  2 ,  3 . In a similar manner, a plurality of leg elastic members  17  sandwiched between the inner and outer sheets  2 ,  3  circumferentially extend along each periphery  13  defining each of the leg-holes  12  and are bonded under tension to at least one of the inner and outer sheets  2 ,  3  so that these leg elastic members  17 , inner and outer sheets  2 ,  3  may form loop-shaped elastic regions  41  around the respective legs. 
       FIG. 2  is a partially cutaway plan view showing a developed diaper  1   a  corresponding to the pants-type diaper  1  of  FIG. 1  having the front and rear waist regions  7 ,  8  peeled off from each other at the seal stripes  9   a  and then fully developed in a transverse direction indicated by a double-headed arrow X as well as in a back-and-forth direction indicated by a double-headed arrow Y which is orthogonal to the transverse direction.  FIG. 2  shows the inner side of such developed diaper  1   a . In the developed diaper  1   a , the pants-shaped skin covering assembly  10  corresponds to a chassis  10   a  having inwardly curved concave shape. The periphery  11   a  of the waist-hole  11  in  FIG. 1  corresponds, in  FIG. 2 , to a front end  7   b  and a rear end  8   b  of the basic structure  10   a  while the peripheries  13  of the respective leg-holes  12  correspond here to transversely opposite edges  13   b  of the crotch region of the chassis  10   a . While these lateral edges  13   b  bow toward a longitudinal center line C-C bisecting a width of the chassis  10   a , the transversely opposite edges  7   a ,  8   a  of the front and rear waist regions  7 ,  8 , respectively, extend in the back-and-forth direction Y substantially in parallel to the longitudinal center line C-C. Leg elastic members  17  extending along the transversely opposite edges  13   b  of the crotch region  6  respectively consist of front elastic members  17   a  extending from the middle of the crotch region  6  as viewed in the back-and-forth direction Y toward the front waist region  7  and rear elastic members  17   b  extending from the middle of the crotch region  6  toward the rear waist region  8  wherein these front and rear elastic members  17   a ,  17   b  intersect one with another in the middle of the crotch region  6 . The core  4  also has inwardly curved concave shape and comprises a mixture  4   a  of fluff pulp fibers and super-absorbent polymer particles wrapped with a covering sheet  4   b  having high absorbability as well as high spreadability for body fluids such as tissue paper. Of the chassis  10   a , the inner sheet  2  defining the inner side thereof is provided in the crotch region  6  with a sheet piece  20  preferably made of a hydrophobic sheet material, more preferably made of a hydrophobic and liquid-impervious sheet material so as to form a pocket  20   a  (See  FIG. 3 ). 
     The sheet piece  20  has transversely opposite edges  23  fixed to the transversely opposite edges  13   b  of the crotch region, respectively, by hot melt adhesive  24 , a front end  21  lying in the crotch region  6  in the vicinity of the front waist region  7  so as to extend in the transverse direction X to the respective lateral edges  13   b  of the crotch region  6  and a rear end  22  lying in the crotch region  6  aside toward the rear waist region  8  so as to extend in the transverse direction X to the respective lateral edges  13   b  of the crotch region  6 . Except for the transversely opposite edges  23 , the sheet piece  20  is substantially free from the inner sheet  2  so that a tunnel- or pocket-like bodily waste receiving space  31  can be between the sheet piece  20  and the inner sheet  2 . The front end  21  and the rear end  22  respectively have sleeves  21   a ,  22   a  formed by folding back the respective ends  21 ,  22  of the sheet piece  20 . These sleeves  21   a ,  22   a  respectively contain a front elastic member  21   b  and a rear elastic member  22   b  attached thereto under tension to form a front elastic region  42  and a rear elastic region  43 , respectively, extending between the transversely opposite edges  13   b  of the crotch region  6 . These elastic regions  42 ,  43  intersect with elastic regions  41  formed by the leg elastic members  17 , the inner sheet  2  and the outer sheet  3  in the chassis  10   a . The front end  21  and the rear end  22  are substantially at equal distances Hf, Hr from a transverse center line D-D and respectively include a front seal region  27  and a rear seal region  28  indicated by imaginary lines on the longitudinal center line C-C. 
       FIG. 3  is a sectional view taken along the line III-III in  FIG. 1  wherein the line III-III conforms to the longitudinal center line C-C. The pants-shaped skin covering assembly  10  includes the front waist region  7  and the rear waist region  8  joined together along the transversely opposite edges  7   a ,  8   a , respectively. The crotch region  6  shown in  FIG. 2  now bows in  FIG. 3  substantially in a U-shape and the transversely opposite edges  13   b  of the crotch region  6  now appear as the peripheries  13  defining the respective leg-holes  12 . The body waste receiving space  31  in the chassis  10   a  appears here as a pocket  20   a  defined by a front seal region  27  of the front waist region  21  and a rear seal region  28  of the rear end  22  of the sheet piece  20  permanently bonded together by bonding agent  32  such as hot melt adhesive or pressure-sensitive adhesive so as to form a seal region  35 . The pocket  20   a  has a front opening  33  defined by the front end  21  of the sheet piece  20  corresponding to a front end of the pocket  20   a  together with the inner sheet  2  and a rear opening  34  defined by the rear end  22  of the sheet piece  20  corresponding to a rear end of the pocket  20   a  together with the inner sheet  2 . At the bottom  6   a  defined by the lowest portion of the crotch region  6 , the inner sheet  2  and the sheet piece  20  are substantially or really in contact with each other. 
       FIG. 4  is an overhead view of the diaper  1  as viewed in a direction indicated by the arrow line IV-IV in  FIG. 3 , i.e., as viewed from above the waist-hole  11 . The front end  21  of the sheet piece  20  has its dimension in the transverse direction X bisected by the seal region  35  into a front end segment  21   R  adapted to be held in close contact with the right leg and a front end segment  21   L  adapted to be held in close contact with the left leg of the wearer (not shown). These front end segments  21   R ,  21   L  describe a V-shape in  FIG. 4 . The rear end  22  also has its dimension in the transverse direction X bisected by the seal region  35 . In the same manner as the front end  21 , the rear end segment  22   R  is adapted to be held in close contact with the right leg of the wearer and the rear end segment  22   L  is adapted to be held in close contact with the left leg of the wearer wherein these rear end segments  21   R ,  21   L  describe a V-shape in  FIG. 4 . The respective peripheries  13  of the leg-holes  12  in the skin covering assembly  10  comprise a periphery  13   R  for the right leg and a periphery  13   L  for the left leg wherein each of the peripheries  13   R ,  13   L  is divided into an upper segment  15   a  not superposed on and left free from the associated lateral edge  23  of the sheet piece  20  and a lower segment  15   b  joined to the associated lateral edge  23  (See  FIG. 3  also). In  FIG. 4 , a range corresponding to the upper segment  15   a  and a range corresponding to the lower segment  15   b  are represented by double-headed arrows A and B, respectively. 
     A sequence in which the pants-type diaper of such configuration is put on the wearer&#39;s body and how the pants-type diaper  1  behaves in the course of being put on the wearer&#39;s body will be described. First, the front and rear waist regions  7 ,  8  of the skin covering assembly  10  are spaced from each other in the back-and-forth direction Y and thereby the waist-hole  11  is broadened as seen in  FIGS. 1 and 4 . Thereupon, the front end segment  21   R  for the right leg and the front end segment  21   L  for the left leg constituting the front end  21  of the sheet piece  20  are deformed about the seal region  35  so as to describe the V-shape and, in a similar way, the rear end segment  22   R  for the right leg and the rear end segment  22   L  for the left leg constituting the rear end  22  of the sheet piece  20  are deformed so as to described the V-shape. Such deformation causes the front opening  33  and the rear opening  34  of the pocket  20   a  to be automatically broadened (See  FIG. 3 ). At the same moment, the front end segment  21   R  for the right leg and the rear end segment  22   R  for the right leg are widely spaced from each other while the front end segment  21   L  for the left leg and the rear end segment  22   L  for the left leg are widely spaced from each other. Now the right leg of the wearer (not shown) is guided through an opening  41   R  for the right leg defined by the upper segment  15   a  of the periphery segment  13   R  of the associated leg-hole  12 , the front end segment  21   R  for the right leg of the sheet piece  20  and the rear end segment  22   R  for the right leg of the sheet piece  20 . The right leg is guided further through the right leg-hole  12  defined by the upper segment  15   a  and the lower segment  15   b  of the periphery segment  13   R  for the right leg. Then the left leg is guided through an opening  41   L  for the left leg defined by the upper segment  15   a  of the periphery segment  13   L  for the left leg, the front end segment  21   L  for the left leg and the rear end segment  22   L  for the left leg. The left leg is guided further through the left leg-hole  12  defined by the upper segment  15   a  and the lower segment  15   b  of the periphery segment  13   L  for the left leg. 
     In the pants-type diaper  1  put on the wearer&#39;s body in the manner as has been described above, the peripheries  13  of the respective leg-holes  12 , i.e., the periphery  13   R  for the right leg and the periphery  13   L  for the left leg are elastically contractible around the respective holes  12  while the front end  21  and the rear end  22  of the sheet piece  20  are elastically contractible in the transverse direction X. In the vicinity of the right groin, therefore, the upper segment  15   a  of the periphery  13   R  for the right leg, the front end segment  21   R  for the right leg and the rear end segment  22   R  for the right leg are elastically held in close contact around the right leg to form a primary seal  51   R  (See  FIG. 4 ) serving to prevent leakage of body fluids from occurring around the right leg. Below the primary seal  51   R , the lower segment  15   b  and the upper segment  15   a  of the periphery  13   R  cooperate integrally with each other to form a secondary seal  52   R  (See  FIG. 4 ) serving to prevent leakage of body fluids from occurring around the right leg. This secondary seal  52   R  functions in a similar manner to the manner in which the leg-surrounding seal in the conventional pants-type diaper function. Just as the case of the right leg, in the vicinity of the left groin, therefore, the upper segment  15   a  of the periphery  13   L  for the left leg, the front end segment  21   L  for the left leg and the rear end segment  22   L  for the left leg are elastically held in close contact around the left leg to form a primary seal  51   L . Below the primary seal  51   L , the lower segment  15   b  and the upper segment  15   a  of the periphery  13   L  cooperate integrally with each other to form a secondary seal  52   L . The pants-type diaper put on the wearer&#39;s body may be sufficiently pulled up along the waist to ensure that the front end  21  and the rear end  22  of the sheet piece  20 , in the vicinity of the seal region  35 , come in contact with a zone of the wearer&#39;s crotch region defined between the wearer&#39;s external genital and anus. Even after the pants-type diaper  1  has been put on the wearer&#39;s body, the front end  21  as well as the rear end  22  of the sheet piece  20  is maintained spaced from the inner sheet  2  and the front opening  33  as well as the rear opening is maintained widely broadened. 
     With the pants-type diaper  1  put on the wearer&#39;s body in this manner, the sheet piece  20  forming the pocket  20   a  distinctly divides the wearer&#39;s crotch region into a front half and a rear half so that the front opening  33  formed in the front half is reliably opposed to the wearer&#39;s external genital and the rear opening  34  is reliably opposed to the anus. Therefore, it is guaranteed that urine discharged from the external genital is guided through the front opening  33  into the pocket  20   a  while feces discharged from the anus is guided through the rear opening  34  into the pocket  20   a . In this way, the pocket  20   a  or sheet piece  20  effectively prevents urine and/or feces from coming in contact with the wearer&#39;s skin. A possibility that urine and feces might be mixed with each other within the bodily waste receiving space  31  is effectively alleviated because the sheet piece  20  is substantially or really maintained in contact with the inner sheet  2  at the bottom  6   a  of the crotch region  6 . Consequentially, an anxiety that a liquidity of feces might be enhanced by admixture of urine and feces is effectively alleviated by the pants-type diaper  1 . Even in the unlikely event that urine and/or feces is not guided into the bodily waste receiving space  31  but moves along the wearer&#39;s legs, the primary seals  51   R ,  51   L  and the secondary seals  52   R ,  52   L  provided around the wearer&#39;s legs cooperate together to prevent urine and/or feces from readily moving out beyond the leg-holes  12  of the pants-type diaper  1 . Alternatively, the inner sheet  2  and the sheet piece  20  may be bonded to each other locally, for example, merely along the bottom  6   a  of the crotch region  6  over the full width in order to eliminate the problem that urine and feces might be mixed with each other within the pants-type diaper  1 . 
     In the pants-type diaper  1  provided by the present invention, stock materials for the inner sheet  2  may be selected from the group including a liquid-pervious nonwoven fabric and a perforated plastic film. Stock materials for the outer sheet  3  may be selected from the group including a liquid-impervious plastic film and a laminated sheet consisting of such plastic film and nonwoven fabric. As liquid-absorbent materials for the core  4 , a mixture of fluff pulp and super-absorbent polymer particles, or fluff pulp fibers alone, or a mixture of fluff pulp fibers and super-absorbent polymer fibers may be used. For the wrapping sheet  4   b , tissue paper often used may be replaced by an appropriate nonwoven fabric. As sheet materials  62  for the sheet piece  20 , a hydrophobic, or a hydrophobic and liquid-impervious nonwoven fabric or a plastic film may be preferably used. More preferably, the sheet materials can be elastic or inelastic so long as it is elastically or inelastically extensible in response to elastic extension of the elastic members  21   b ,  22   b . When the sheet piece  20  is elastically contractible, the front elastic member or the rear elastic member can be omitted. If the inner and outer sheets  2 ,  3  and the other sheet material such as the sheet piece  20  contain any heat-fusible plastics, these sheet materials may be heat-sealed by the known sonic sealing technique. 
     The sheet piece  20  of the chassis  10   a  shown by  FIG. 2  is attached to the chassis  10   a  so that the distance Hf from the transverse center line D-D to the front joint region  27  is equal to the distance Hr from the transverse center line D-D to the rear joint region  28 . In the case of the sheet piece  20  used in the pants-type diaper  1  for baby, each distance Hf, Hr is preferably in a range of 20 to 150 mm, more preferably in a range of 40 to 80 mm. In addition, a dimension of the front and rear joint regions  27 ,  28  in the transverse direction X is preferably in a range of 3 to 50 mm, more preferably in a range of 10 to 30 mm. A dimension of the sheet piece  20  in the back-and-forth direction Y is at least 3 mm. Alternatively, it is possible to dimension the sheet piece  20  in the transverse direction X to be less than that in the illustrated embodiment so that the transversely opposite edges  23  thereof may be placed aside from the transversely opposite edges  13  of the chassis  10   a  toward the center line C-C in the back-and-forth direction. 
     The chassis  10   a  of  FIG. 2  further includes a pair of side flaps  25  defined by portions of the inner and outer sheets  2 ,  3  extending outward in the transverse direction X beyond the transversely opposite edges of the core  4 . The side flaps  25  have flexural stiffness in the transverse direction X lower than that of the core  4  and are correspondingly easier to be deformed. These side flaps  25  include the leg elastic regions  41 . When the pants-type diaper  1  obtained from the chassis  10   a  is in a state of  FIG. 1  wherein the crotch region  6  bows in a U-shape in the front-and-rear direction Y, the side flaps  25  tend to raise themselves up along the lateral opposite edges  4   c  of the core  4  under contraction of the elastic regions  41  in the vicinity of the transverse center line D-D, i.e., at the bottom  6   a  of the crotch region  6 . On the other hand, the sheet piece  20  is bonded along the transversely opposite edges  23  thereof to the inner surface of the elastic regions  41  by adhesive  24 . In response to deformation of the front and rear ends  21 ,  22  of the sheet piece  20  in a V-shape as shown in  FIG. 4  from the state thereof shown in  FIG. 2  wherein these front and rear ends  21 ,  22  rectilinearly extend, these front and rear ends  21 ,  22  function to pull the side flaps  25  toward the longitudinal center line C-C and thereby enhance the behavior of the side flaps  25  to raise themselves up. The side flaps  25  behaving in this manner are reliably held in close contact around the legs of the wearer from below and thereby effectively prevent leak of body fluids from possibly occurring around the legs. However, if such leakage preventing effect is not required for the pants-type diaper  1 , the leg elastic members  17   a ,  17   b  may be saved. 
       FIG. 5  through  FIG. 9  are diagrams exemplarily illustrating step of the process for continuously making the pants-type diaper  1  of  FIG. 1 . In these diagrams, a machine direction is indicated by an arrow MD and a cross direction orthogonal to the machine direction MD is indicated by a double-headed arrow CD. 
     In a first step I illustrated in  FIG. 5 , a first web  201  is continuously fed in the machine direction MD, preferably under tension in the machine direction MD as well as in the CD direction. This first web  201  is laminate consisting of a continuous inner sheet  102  corresponding to the liquid-pervious inner sheet  2  of the chassis  10   a  (See  FIG. 2 ) which is continuous in its transverse direction X and a continuous outer sheet  103  corresponding to the liquid-impervious outer sheet  3  which has the same width as that of the continuous inner sheet  102  and continuous in its transverse direction X. Between these two continuous inner and outer sheets  102 ,  103 , a plurality of body fluid absorbent cores  104  are sandwiched at regular center intervals each corresponding to the width of the chassis  10   a  in the machine direction MD and bonded to at least one of these continuous inner and outer sheets  102 ,  103  by hot meld adhesive (not shown). The continuous inner and outer sheets  102 ,  103  also are bonded to each other by hot melt adhesive (not shown). An imaginary line  151  extending in the cross direction CD in the middle between each pair of the adjacent cores  104  indicates a position at which the assembly including the first web  201  will be cut in a subsequent step (See  FIG. 9 ) and a dimension between each pair of the adjacent imaginary lines  151 ,  151  is equal to the width of the chassis  10   a . A loop-shaped imaginary line  152  illustrated in the middle region of first web  201  as viewed in the cross direction CD is illustrated to be bilaterally symmetric about the imaginary line  151  and symmetric also in the vertical direction, i.e., in the cross direction CD. This loop-shaped imaginary line  152  indicates a boundary surrounding a region which will be cut away in a subsequent step (See  FIG. 9 ). Immediately outside the imaginary line  152 , leg elastic members  117   a ,  117   b  extend along the imaginary line  152  so as to be sandwiched between the continuous inner and outer sheets  102 ,  103  and bonded to at least one of these continuous inner and outer sheets  102 ,  103  by hot melt adhesive (not shown). These elastic members  117   a ,  117   b  respectively trace substantially semicircular courses and intersect one another so as to describe together a loop wherein these elastic members  117   a ,  117   b  are under tension at least partially along this loop. The first web  201  is further provided along edges  107   b ,  108   b  thereof extending in parallel to each other in the machine direction MD with elastic members  114   a ,  114   b  respectively extending under tension in the machine direction MD. These elastic members  114   a ,  114   b  are bonded to the inner surface of at least one of the continuous inner and outer sheets  102 ,  103  by hot melt adhesive (not shown). The opposite edges  107   b ,  108   b  of the first web  201  are nipped in thickness direction thereof by associated sets of feed rolls  153 , respectively, which are paired in the cross direction and adapted to feed the first web  201  under tension in the machine direction MD. The sets of feed rolls  153  paired in this manner are intermittently disposed at appropriate intervals in the machine direction MD. While axes  154  of these feed rolls  153  are illustrated to extend orthogonally to the machine direction MD, an angle of these axes  154  with respect to the machine direction MD may be appropriately varied, if desired. In addition to these feed rolls  153 , tentering rolls  156  paired in the cross direction are disposed in appropriate regions along the opposite edges  107   b ,  108   b  so that these tentering rolls  156  may be held in contact with the continuous inner sheet  102  and thereby tenter the first web  201  in the cross direction CD. While axes  157  of the respective tentering rolls  156  are illustrated to intersect with the machine direction MD obliquely at a particular angle, this angle is not limited to the particular angle as illustrated. An imaginary line p-p in  FIG. 5  indicates a first center line bisecting the first web  201  in the cross direction CD. It will be appreciated that the first web  201  may be fed in the machine direction MD by any means replacing the rolls  153 ,  156  used in the illustrated embodiment. In the illustrated embodiment, the first web  201  may be successively cut at a pitch corresponding to a distance between each pair of the adjacent imaginary lines  151 ,  151  to obtain the chassis  10   a  in a continuous fashion. 
     In a second step II illustrated in  FIG. 6 , a second web  202  comprising the sheet pieces  20  destined to be attached to the associated chassis  10   a  and continuously arranged in the transverse direction X is continuously fed in the machine direction MD preferably under tension in the machine direction MD as well as in the cross direction CD. For this step of feeding, feed rolls  158  and tentering rolls  159  are used. The second web  202  has a pair of edges  121   c ,  122   c  extending in parallel to each other in the machine direction MD and the one edge  122   c  of these edges  121   c ,  122   c  is coated at regular pitches each corresponding to the width of the chassis  10   a , i.e., corresponding to the distance between each pair of the adjacent imaginary lines  151 ,  151  as illustrated in  FIG. 5  with bonding agent  132  such as pressure-sensitive adhesive. An imaginary line q-q indicated in  FIG. 6  defines a second center line bisecting the second web into two dimensions Hf, Hr in the cross direction CD. 
     In a third step III illustrated by  FIG. 7 , the second web  202  is folded back onto itself along a folding guide line defined by the second center line q-q with the bonding agent  132  inside and thereby the respective halves of the second web  202  folded back in this manner are locally bonded to each other by the bonding agent  132  to obtain a third web  203  having a seal region  135 . The third web  203  also can be fed in the machine direction MD using the feed rolls  158  and the tentering rolls  159 . 
     In a fourth step IV illustrated by  FIG. 8 , the first web  201  corresponding to the continuous inner sheet  102  is coated immediately outside and along the loop-shaped imaginary line  152  with hot melt adhesive  124 . The range over which the continuous inner sheet  102  is coated with the adhesive  124  extends on both sides from the first center line p-p in the cross direction CD by a distance m, preferably so that this range extends sufficiently to cover the elastic members  117   a ,  117   b.    
     In a fifth step V illustrated by  FIG. 8 , the third web  203  is superposed upon the continuous inner sheet  102  in the first web  201  so that the second center line q-q falls in which the first center line p-p and the seal region  135  is located in the middle between the adjacent imaginary lines  151 ,  151 , in other words, located in the middle of the chassis  10   a  as viewed in the transverse direction thereof. The first web  201  and the third web  203  are bonded together by the adhesive  124  coated on the first web  201  and thereby a first composite web  301  is obtained. In the first composite web  301 , the first web  201  and the third web  203  are free from each other in the remaining region with respect to the region occupied by the adhesive  124 . Alternatively, the third web  203  may be bonded to the first web  201  in the vicinity of the middle between each pair of the adjacent imaginary lines  151 ,  151 . The elastic members  114   a ,  114   b ,  117   a ,  117   b ,  121   b ,  122   b  are indicated by chained lines as if seen through but the adhesive  124  is not indicated. It should be understood that the first center line p-p and the second center line q-q to fall in with each other in the fifth step V may be misaligned with each other so far as such alignment does not disturb making and use of the pants-type diaper. 
     In a sixth step VI illustrated by  FIG. 9 , the first composite web  301  is folded back onto itself along a folding guide line defined by the first center line p-p of the first web  201  with the third web  203  inside wherein the first web  201  and the third web  203  superposed upon each other are bonded together by the adhesive  124  (See  FIG. 8 ) to obtain a second composite web  302 . In the course of bonding, the first web  201  and the third web  203  may be compressed in thickness direction thereof to assure desired bonding effect. The loop-shaped imaginary line  152  described on the first web  201  to be symmetric about the first center line p-p now describes on the second composite web  302  a circular arc which is convex from a chord defined by the first center line p-p toward the edges  107   b ,  108   b  (See  FIG. 5 ) falling in with each other so as to describe a substantially semicircular shape which is bilaterally symmetric as viewed in the machine direction. The region in which the first web  201  and the third web  203  are bonded to each other by the adhesive  124  in the sixth step VI is superposed on the region in which the first web  201  and the third web  203  are bonded to each other by the adhesive  124  in the fifth step V. In the sixth step VI also, the first web  201  and the third web  203  are free from each other in the remaining region with respect to the region occupied by the adhesive  124 . 
     In the seventh step VII illustrated by  FIG. 9 , the section surrounded by the substantially circular imaginary line  152  is clipped out from the second composite web  302  to obtain the third composite web  303  having a substantially semicircular notch  112 . This clipping step generates scrap in the form of substantially semicircular web pieces  215  clipped out from the second composite web  302 . Each notch  112  is substantially semicircular shaped and symmetric about the imaginary line  151 . 
     In the eighth step VIII illustrated by  FIG. 9 , the inner surface of the first web  201  folded in two is bonded to itself on both sides of the imaginary line  151  along two seal regions each comprising a plurality of seal stripes  109   a ,  109   b  to obtain a fourth composite web  304 . To achieve the desired bonding effect, appropriate bonding means such as sonic sealing technique or hot melt adhesive may be used. A plurality of seal stripes  109   a  and a plurality of seal stripes  109   b  form linear seal regions  109 , respectively, which are belt-like regions extending in the cross direction CD. 
     In the step IX illustrated by  FIG. 9 , the fourth web  304  is cut along the imaginary line  151  bisecting the seal region  109  in the machine direction MD to obtain the individual pants-type diaper  1 . 
     The chassis  10   a  and the sheet piece  20  in the pants-type diaper  1  shown in  FIG. 1  is obtained from the first web  201  and the second web  202 , respectively, used in the steps illustrated by  FIGS. 5 through 9 . The inner sheet  2 , the outer sheet  3  and the liquid-absorbent core  4  are obtained from the continuous inner sheet  102 , the continuous outer sheet  103  and the liquid-absorbent core  104 , respectively. The periphery of the circular notch  112  is destined to form the peripheries  13  of the leg-holes  12  in the diaper  1  and the elastic members  117   a ,  117   b  are respectively divided in right and left halves along the imaginary line  151  to form the front elastic members  17   a  and the rear elastic members  17   b  of the respective leg elastic members  17  shown in  FIG. 2 . The elastic members  114   a ,  114   b  in the first web  201  correspond to the waist elastic members  14   a ,  14   b  in  FIG. 1 , respectively. 
     The method for making the pants-type diaper exemplarily illustrated allows the first web  201 , the second web  202 , the third web  203  and the like to be maintained under tension in the machine direction MD as well as in the cross direction CD by the feed rolls and the tentering rolls disposed at appropriate locations along the edges of these webs, respectively. There is no need for chucks or the like used only for the purpose of keeping these first and second webs  201 ,  202  under tension and therefore both the first web  201  and the second web  202  are not wasted in the course of making the pants-type diaper  1 . In addition, the pants-type diaper  1  made by the method of the invention advantageously facilitates the external genitals and the anus of the wearer to be exactly opposed to the front opening  33  and the rear opening  34 , respectively, of the pocket  20   a  in the diaper  1  (See  FIGS. 1 ,  3  and  4 ). According to the exemplarily illustrated method, the second web  202  destined to form the pocket  20   a  is folded in two so as to obtain the third web  203  carrying the seal region  135  before the third web  203  is bonded to the first web  201 . In this way, formation of the seal region  35  in the pants-type diaper  1  would not be accompanied with any significant difficulty. 
     The present invention is not limited to the steps exemplarily illustrated but contents of the respective steps as well as the order of these steps may be variously modified without departing from the object of the present invention. For example, in the step IV, the first web  201  may be previously coated with the adhesive  124  along the segment of the loop-shaped imaginary line  152  extending above the first center line p-p and then the third web  203  may be bonded to the first web  201 . Thereafter, the first web  201  may be coated with the adhesive  124  along the segment of the loop-shaped imaginary line  152  extending below the first center line p-p and then the first web  201  may be folded back along the first center line p-p so that the first web  201  and the third web  203  thus superposed on each other may be bonded to each other. In the step modified in this manner, even when the first web  201  and the third web  203  are bonded to each other under a compression, the presence of the adhesive  124  coated on the first web  201  would not pose an impediment on the operation of compression. Furthermore, the step VII and the step VIII may be order-reversed in the method exemplarily illustrated so that the notch  112  may be formed after the second composite web  302  has been formed with the seal region  109 . In the case of the second web  202  is formed by a nonwoven fabric made of thermoplastic synthetic fibers, the respective halves of the second web  202  may be bonded together by sonic sealing technique instead of the bonding agent  132 .