Abstract:
Apparatus and methods are provided to allow for creation of a cross-machine direction fold boundary, so that a laminate with a defined foldover can be created. A laid open two-ply material can then undergo processing operations such as addition of discrete disposable product components, or printing, and then be laid closed and sealed to form disposable products.

Description:
RELATED APPLICATION 
       [0001]    This application claims the benefit of co-pending U.S. Provisional Application Ser. No. 61/428,678, filed 30 Dec. 2010. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention relates to an apparatus and method for creating a cross-machine direction fold line boundary that can be used in production of disposable absorbent articles. 
       SUMMARY OF THE INVENTION 
       [0003]    In order to present a two-ply material with the plies spread open, two or more layers of material can be laid on one another and bonded to one another intermittently in the machine direction, at a relatively short cross-machine direction dimension. The top (or bottom) layers can then be folded over to present a laid-open type presentation so that material can be sandwiched between the plies, or other processing operations could be performed on the interior of the plies. In this manner, the bonding (either intermittent in the machine direction, or continuous down the length of the web in the machine direction) of the plies creates a boundary in the cross-machine direction, past which the fold cannot proceed in the cross-machine direction. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  is a side view schematic of a representative web processing system; 
           [0005]      FIG. 2A  is a perspective view of a two ply material advancing in the machine direction, with intermittent bonds extending partially across the plies in the cross-machine direction; 
           [0006]      FIG. 2B  is a cross-sectional view of a two ply material intermittently bonded; 
           [0007]      FIG. 3A  is a perspective view of a two ply material advancing in the machine direction, with intermittent bonds extending partially across the plies in the cross-machine direction, the top ply having been folded over in the cross-machine direction to the intermittent bonds, the intermittent bonds creating a boundary which the foldover cannot go past; 
           [0008]      FIG. 3B  is a cross-sectional view of the product shown in  FIG. 3A ; 
           [0009]      FIG. 4A  is a perspective view of a two ply material advancing in the machine direction, with intermittent bonds extending partially across the plies in the cross-machine direction, as well as coterminous bonds extending widthwise in the cross machine direction; 
           [0010]      FIG. 4B  is a cross-sectional view of the product shown in  FIG. 4A . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0011]    Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims. 
         [0012]    It is noted that the present techniques and apparatus are described herein with respect to products such as diapers, but as previously mentioned, can be applied to a wide variety of processes in which discrete components are applied sequentially. 
         [0013]    Referring now to  FIG. 1 , a side view schematic of a representative web processing system  10  is shown. Two plies of material  12  and  14  are laid down and pass through a bonding unit  16  to create intermittent bond sites  24 , and optionally, patterned bond sites  34  (see  FIG. 2A ). The bonding unit  16  can be configured to create both the bond sites  24  and  34 , or an additional bonding unit  16  can be employed to create the bond sites  34  (not shown). 
         [0014]    In an optional embodiment, the intermittent bond sites  24  can instead be a continuous bond  24  running the length of the web in the machine direction (not shown). 
         [0015]    Plies of material  12  and  14  can be non-woven, woven, elastic or inelastic etc. Generally, non-woven materials are preferred during some applications in diaper making. The bonding unit  16  can be and is preferred to be an ultrasonic bonding unit (horn/anvil) but of course any type of bond can be used to create the cross-machine direction fold boundary of the present invention, created by the intermittent bond sites  24 . 
         [0016]    After passing through the bonding unit  16 , the two plies  12  and  14  pass through a unit  18 , such as a folding or unfolding plow (such as those disclosed in U.S. Pat. Nos. 4,171,239 or 7,374,627, incorporated herein by reference) to overturn one of the layers  12  or  14 . Next, as will be described later, a processing operation  20  can be performed on the laid open two ply laminate, the laid-over or laid-open ply can then be re-folded back to its original laid closed orientation, and an additional bonding unity  16  can be used to further and additionally bond the plies  12  and  14  as desired. 
         [0017]    Referring now to  FIG. 2A , the first steps of the processing operation are shown in a perspective view of a two ply material advancing in the machine direction. As can be seen, plies  12  and  14  have been bonded intermittently in the machine direction at intermittent bond sites  24 , which define the cross-machine direction boundary at which the fold  28  (see 
         [0018]      FIG. 3A ) will be effective upon the ply  14 . It is preferred that bond sites  24  are spaced apart in the machine direction, preferably at a distance of some multiple of the product pitch, and that the bond sites  24  extend from relatively close to an edge of the plies  12  and  14  in the cross-machine direction. 
         [0019]    The width of the bond sites  24  in the cross-machine direction is according to user preference and the design of the disposable product for which the plied material will eventually be used with. However, it is preferred that the width of the bond sites be coextensive with how wide the fold-over (described later) is desired. 
         [0020]    The optional patterned bond sites  34  (shown in an exemplary embodiment as chevron-shaped) can be positioned either co-extensive in the cross-machine direction with the fold line  28  (not shown), or positioned closer to the non-folded edge of the plies  12  and  14  as shown in  FIGS. 2A and 3A . 
         [0021]    Referring to  FIG. 2B , a cross-sectional view of a two ply material intermittently bonded is shown. This orientation, with plies  12  and  14  in their original orientation, is considered a “closed” orientation. 
         [0022]    Referring now to  FIG. 3A , a perspective view of the two ply  12 / 14  material advancing in the machine direction, with intermittent bonds  24  extending partially across the plies  12 / 14  in the cross-machine direction is shown in an “open” or “laid open” orientation. The top ply  14  has been folded over in the cross-machine direction by folding plow  18  (see  FIG. 18 ) to the intermittent bonds  24  to fold line  28 , which is coextensive in the cross machine direction to the edge of the bond site  24  farthest from the edge of the web  10 . In the cross machine direction, the intermittent bonds  24  effectively created a boundary or fold line  28  which the foldover cannot go past. 
         [0023]      FIG. 3B  is a cross-sectional view of the product shown in  FIG. 3A  in the laid open orientation. With the interior of the two ply  12 / 14  laminate having been exposed, processing operations can be performed on the interior by processors  20  ( FIG. 1 ). For instance, if certain discrete portions of a disposable product are desired to be introduced in sandwich fashion, the discrete elements can be added to the interior of the two plies at this point. The discrete elements (not shown) can be absorbent cores, laminates, additives. Alternatively, certain operations such as scent additive or printing can be performed on the interiors of plies  12 / 14  in this laid open configuration. 
         [0024]    Referring now to  FIG. 4A , the next step is to re-fold the top ply  14  back to its closed orientation, by use of folding plow  22  ( FIG. 1 ). A perspective view of the two ply material advancing in the machine direction, with intermittent bonds  24  extending partially across the plies  12 / 14  in the cross-machine direction is shown. After the processing operations  20  have been performed and the plies  12 / 14  are returned to their closed orientation, it is preferred to pass the material through an additional intermittent bonding unit  16  to create coterminous bonds  26  extending generally in the width of the web  10  in the cross-machine direction. These coterminous bonds  26  extending widthwise in the cross machine direction at a preferred spacing to match intermittent bonds  24  and at a spacing of one or more bonds per product in the machine direction, in order to separate products. The closed orientation of the two ply material is shown in  FIG. 4B , with the laminate returned to its closed orientation. 
         [0025]    The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.