Patent Abstract:
A method allows for rapid manufacture of relatively thick adhesive coatings using a continuous process, where a single thin coating is continuously converted into a single thicker adhesive laminate. An exemplary process includes the steps of: (1) producing a web having a first surface with an adhesive layer and a second surface with a release liner; (2) slitting the web longitudinally into a first section and a second section, each section having a first surface with an adhesive layer and a second surface with a release liner; (3) laminating a backing film to the adhesive layer of the first section; (4) removing the release liner of the laminate of step (3) exposing the adhesive layer of the first section; (5) positioning the laminate of step (4) and the second section so the exposed adhesive layer of the laminate of step (4) faces the adhesive layer of the second section; and (6) laminating the second section to the laminate of step (4), wherein the adhesive layer of the laminate of step (4) is combined with the adhesive layer of the second section. The resultant laminate of this exemplary process has one surface having a backing film, one surface having a release liner, and an inner area having an adhesive layer.

Full Description:
PRIORITY 
       [0001]    This application claims priority from the disclosure of U.S. Provisional Patent Application Ser. No. 61/102,223, entitled “Method for Making a Multilayer Adhesive Laminate,” filed Oct. 2, 2008, the disclosure of which is incorporated by reference herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention is in the field of pressure sensitive adhesive coatings. 
       BACKGROUND 
       [0003]    Pressure-sensitive adhesive laminates are common in products from numerous industries, including the medical and consumer healthcare industries. Within these industries, pressure-sensitive adhesive laminates may be used for transdermal patches, medical tapes, wound dressings, and topical skin patches. While this section and the disclosure herein may focus on medical and consumer healthcare applications, it should be understood that this disclosure is not limited to these applications or industries. 
         [0004]    A common process used to manufacture pressure-sensitive adhesive laminates involves a continuous solvent-based adhesive coating process. Such a process may employ any suitable type of solvent, including water. However, the thickness of the adhesive coating produced by such a process is limited. For instance, to achieve a thicker adhesive-coated product using a solvent-based adhesive coating processes, it is necessary to slow production speeds to give thicker adhesive coatings adequate drying time, or increase temperatures, which may cause the formation of surface imperfections. Alternatively, one may use such a process in batch mode to combine layers to produce thicker adhesive laminates. These approaches to producing thick or multilayer adhesive laminates are cost intensive and inefficient. Therefore, there is a need for a process that allows for continuous rapid manufacture of a relatively thick adhesive laminate. 
       SUMMARY 
       [0005]    The processes described herein allow for continuous rapid manufacture of relatively thin adhesive coatings, where the thin coatings are continuously manufactured into a single thicker adhesive laminate. 
         [0006]    In one embodiment, this disclosure pertains to a method of continuously manufacturing a multilayer pressure-sensitive adhesive laminate including the steps of: (1) producing a web having a first surface with an adhesive layer and a second surface with a release liner; (2) slitting the web longitudinally into a first section and a second section, each section having a first surface with an adhesive layer and a second surface with a release liner; (3) positioning the first section and second section so the adhesive layer of the first section faces the adhesive layer of the second section along the length of the first and second sections; and (4) laminating the first section and second section together such that the adhesive layers of the first and second sections are attached. The resultant laminate has two surfaces each having a release liner and an inner area having an adhesive layer. 
         [0007]    In another embodiment, this disclosure pertains to a method of continuously manufacturing a multilayer pressure-sensitive adhesive laminate including the steps of: (1) producing a web having a first surface with an adhesive layer and a second surface with a release liner; (2) slitting the web longitudinally into a first section and a second section, each section having a first surface with an adhesive layer and a second surface with a release liner; (3) laminating a backing film to the adhesive layer of the first section; (4) removing the release liner of the laminate of step (3) and exposing the adhesive layer of the first section; (5) positioning the laminate of step (4) and the second section so the exposed adhesive layer of the laminate of step (4) faces the adhesive layer of the second section; and (6) laminating the second section to the laminate of step (4), wherein the adhesive layer of the laminate of step (4) is combined with the adhesive layer of the second section. The final laminate has one surface having a backing film, one surface having a release liner, and an inner area having an adhesive layer. 
         [0008]    In another embodiment, this disclosure pertains to a method of continuously manufacturing a multilayer pressure-sensitive adhesive laminate including the steps of: (1) producing a web having a first surface with an adhesive layer and a second surface with a release liner; (2) slitting the web longitudinally into a plurality of sections, each of the plurality of sections having a first surface with an adhesive layer and a second surface with a release liner; (3) laminating a backing film to the adhesive layer of a first section of the plurality of sections; (4) removing the release liner of the laminate of step (3) and exposing the adhesive layer associated with the first section; (5) positioning the laminate of step (4) and a next section of the plurality of sections so the exposed adhesive layer of the laminate of step (4) faces the adhesive layer of the next section; (6) laminating the next section to the laminate of step (4), wherein the adhesive layer of the laminate of step (4) is combined with the adhesive layer of the next section; (7) removing the release liner of the laminate of step (6) exposing the adhesive layer associated with the next section; and (8) repeating steps (5) through (7) to achieve a desired number of laminated layers; wherein step (7) is omitted with the final laminated section of the plurality of sections. The final laminate has one surface having a backing film, one surface having a release liner, and an inner area having an adhesive layer. 
         [0009]    The above embodiments are exemplary only and should not be interpreted to limit the scope of this disclosure. It should be understood that this disclosure encompasses numerous embodiments, some of which are not explicitly disclosed within this section. Ultimately, the scope of this disclosure is defined by the broadest reading of the claims herein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The accompanying drawings are incorporated in and constitute a part of this specification. Together with the detailed description given below, the drawings serve to explain how the teachings of this application could be implemented. It should be understood that the teachings of this application are not limited to being implemented in the precise arrangements shown. In the drawings: 
           [0011]      FIG. 1A  depicts a flow diagram of a method to make a multilayer adhesive laminate having an adhesive coating between two release liners. 
           [0012]      FIG. 1B  depicts a schematic diagram of an exemplary process for the method shown in  FIG. 1A . 
           [0013]      FIG. 1C  depicts a cross-section view of the adhesive coated release liner strips used in the lamination process of  FIG. 1B . 
           [0014]      FIG. 1D  depicts a cross-section view of the multilayer adhesive laminate produced in the lamination process of  FIG. 1B . 
           [0015]      FIG. 2A  depicts a flow diagram of a method to make a multilayer adhesive laminate having an adhesive coating between a release liner and a backing film. 
           [0016]      FIG. 2B  depicts a schematic diagram of an exemplary process for the method shown in  FIG. 2A . 
           [0017]      FIG. 2C  depicts a cross-section view of the adhesive coated release liner strips used in the lamination process of  FIG. 2B . 
           [0018]      FIG. 2D  depicts a cross-section view of the adhesive coated release liner strip containing the backing film as used in the lamination process of  FIG. 2B . 
           [0019]      FIG. 2E  depicts a cross-section view of the strip of  FIG. 2D  with the release liner removed. 
           [0020]      FIG. 2F  depicts a cross-section view of the multilayer adhesive laminate produced in the lamination process of  FIG. 2B . 
           [0021]      FIG. 3A  depicts a flow diagram of a method to make a multilayer adhesive laminate having an adhesive coating between a release liner and a backing film. 
           [0022]      FIG. 3B  depicts a schematic diagram of an exemplary process for the method shown in  FIG. 3A . 
           [0023]      FIG. 3C  depicts a cross-section view of the adhesive coated release liner strips used in the lamination process of  FIG. 3B   
           [0024]      FIG. 3D  depicts a cross-section view of the adhesive coated release liner strip containing the backing film as used in the lamination process of  FIG. 3B . 
           [0025]      FIG. 3E  depicts a cross-section view of the strip of  FIG. 3D  with the release liner removed. 
           [0026]      FIG. 3F  depicts a cross-section view of the strip of  FIG. 3E  after an additional strip of adhesive coated release liner has been laminated to the strip of  FIG. 3E . 
           [0027]      FIG. 3G  depicts a cross-section view of the strip of  FIG. 3F  with the release liner removed. 
           [0028]      FIG. 3H  depicts a cross-section view of the strip of  FIG. 3G  after an additional strip of adhesive coated release liner has been laminated to the strip of  FIG. 3G . 
           [0029]      FIG. 3I  depicts a cross-section view of the multilayer adhesive laminate produced in the lamination process of  FIG. 3B . 
       
    
    
     DETAILED DESCRIPTION 
       [0030]    In discussing the figures, specific frame of reference conventions are designated, which includes describing an upward and downward orientation. When viewing the exemplary process figures ( FIGS. 1B ,  2 B, and  3 B), an upward orientation is associated with an object facing out-of-the-page, whereas a downward orientation is associated with an object facing into-the-page. When viewing the laminate schematic figures ( FIGS. 1C-1D ,  2 C- 2 F, and  3 C- 3 I), an upward orientation is associated with an object facing the top of the page, whereas a downward orientation is associated with an object facing the bottom of the page. These frame of reference conventions are used only for aiding in understanding the disclosure. In no sense should the disclosure be limited to such a frame of reference as other suitable manners of description fall within the scope of this disclosure. 
         [0031]      FIG. 1A  describes a process for manufacturing a multilayer adhesive laminate by pairing two adhesive coatings between release liners. At step  100 , a coating of adhesive is applied to a release liner, using any suitable coating method, to produce a coated web. Step  105  is a curing process, using any suitable method, where the adhesive-coated web is converted from a fluid to a fixed film. A suitable curing process may include, but is not limited to, a drying process. At step  110 , the cured web is slit into two strips using any suitable slitting method. At step  115 , the separate strips are directed through the process to orient the adhesive layers of the two strips such that they face one another in preparation for lamination. At step  125 , the adhesive layers of the two strips are laminated together, using any suitable lamination method, to form a multilayer adhesive laminate having an inner adhesive layer surrounded on both sides by a release liner. 
         [0032]    Referring to  FIG. 1B , a schematic shows an exemplary way to direct the strips to achieve the multilayer adhesive laminate discussed in  FIG. 1A . In  FIG. 1B , web section  130  is the adhesive coated web after curing step  105  of  FIG. 1A . Web section  130  travels through slitter  135  where web section  130  is divided into strip sections  140  and  145 . Strip section  140  travels over 45-degree turning roller  160 , which causes a change in the surface orientation of strip section  140 , and causes strip section  140  to change its direction of travel by about 90-degrees.  FIGS. 1B and 1C  show that before strip section  140  passes over 45-degree turning roller  160 , adhesive layer  175  of strip section  140  faces upward (and conversely the release liner  180  faces downward). After passing over 45-degree turning roller  160 , adhesive layer  175  of strip section  140  faces downward (and conversely the release liner  180  faces upward). 
         [0033]    Still referring to  FIG. 1B , strip section  145  is directed to 90-degree turning roller  150 , which causes a change in the surface orientation of strip section  145 , and causes strip section  145  to reverse its direction of travel. As shown from  FIGS. 1B and 1C , adhesive layer  190  of strip section  145  faces upward (and conversely the release liner  185  faces downward) before passing over 90-degree turning roller  150 . After passing over 90-degree turning roller  150 , adhesive layer  190  of strip section  145  faces downward (and conversely the release liner  185  faces upward). Strip section  145  is then directed to 45-degree turning roller  155 , which causes a change in the surface orientation of strip section  145 , and causes strip section  145  to change its direction of travel by about 90-degrees. As shown in  FIG. 1B , 45-degree turning roller  155  is located such that after turning roller  155 , strip section  145  aligns with strip section  140 , and strip section  140  travels above strip section  145  in the same direction. Those of ordinary skill in the art will appreciate that heights of strip sections  140  and  145  may be manipulated by positioning turning rollers or web guides at different heights with respect to a common plane of reference. Furthermore, as shown in  FIG. 1B , after passing over 45-degree turning roller  155 , adhesive layer  190  of strip section  145  now faces adhesive layer  175  of strip section  140 . 
         [0034]    Still referring to  FIG. 1B , with strip sections  140  and  145  oriented as described above, strip sections  140  and  145  then pass through a lamination section  165 . Lamination section  165  causes the adhesive layers  175  and  190 , of strip sections  140  and  145  respectively, to join forming a multilayer adhesive laminate  170 . As shown in  FIGS. 1B and 1D , the multilayer adhesive laminate  170  has a combined adhesive layer  195 , surrounded on either side by release liners  180  and  185 . It should be noted that combined adhesive layer  195  is comprised of adhesive layer  175  of strip section  140  and adhesive layer  190  of strip section  145 . 
         [0035]    Now referring to  FIG. 2A , a process is shown for manufacturing a multilayer adhesive laminate by pairing two adhesive coatings between a release liner and a backing film. At step  200 , an adhesive coating is applied to a release liner using any suitable coating method. At step  205 , the web containing the adhesive coating and release liner is cured using any suitable method. At step  210 , the web is slit into two strips using any suitable slitting method. At step  215  a backing film is attached to the adhesive layer of one of the strips. From this same strip, at step  220 , the release liner is removed, thus exposing the adhesive layer of the strip opposite the side of the backing film. At step  223 , the separate strips are then directed through the process to orient the adhesive layers of the two strips such that they face one another in preparation for lamination. At step  225  the adhesive layers of the two strips are laminated together using any suitable lamination method to form a multilayer adhesive laminate. 
         [0036]    Referring to  FIGS. 2B-2F , a schematic shows an exemplary way to direct the strips to achieve the multilayer adhesive laminate discussed in  FIG. 2A . In  FIG. 2B , web section  230  is the adhesive-coated web after curing step  205  of  FIG. 2A . Web section  230  travels through slitter  235  where web section  230  is divided into strip sections  240  and  245 . Strip section  245  travels to backing film application section  255 , where backing film  250  is attached to adhesive layer  295  of strip section  245  to produce strip section  290  having a backing film  250 , an adhesive layer  295 , and a release liner  265  as shown in  FIGS. 2B and 2D . Strip section  290  then travels to a release liner removal section  260 . Release liner  265  is removed from strip section  290  to produce strip section  296 . As shown in  FIG. 2E , strip section  296  has backing film  250  on top of adhesive layer  295 , which now has an exposed adhesive surface where release liner  265  was formerly positioned. Strip section  296  travels over 45-degree turning roller  275 , which causes a change in the surface orientation of strip section  296 , and causes strip section  296  to change its direction of travel by about 90-degrees.  FIGS. 2B and 2E  show that before strip section  296  passes over 45-degree turning roller  275 , backing film  250  of strip section  296  faces upward (and conversely the adhesive layer  295  faces downward). After passing over 45-degree turning roller  275 , backing film  250  of strip section  296  faces downward (and conversely the adhesive layer  295  faces upward). 
         [0037]    Still referring to  FIGS. 2B-2F , strip section  240  is directed into 45-degree turning roller  270 , which causes a change in the surface orientation of strip section  240 , and causes strip section  240  to change its direction of travel by about 90-degrees.  FIGS. 2B and 2C  show that before strip section  240  passes over 45-degree turning roller  270 , adhesive layer  299  of strip section  240  faces upward (and conversely the release liner  297  faces downward). After passing over 45-degree turning roller  270 , adhesive layer  299  of strip section  240  faces downward (and conversely the release liner  297  faces upward). As shown in  FIG. 2B , 45-degree turning rollers  270  and  275  are located such that strip sections  240  and  296  align, and such that strip section  240  is traveling above strip section  296  and in the same direction and speed. Those of ordinary skill in the art will appreciate that heights of strip sections  240  and  296  may be manipulated by positioning turning rollers or web guides at different heights with respect to a common plane of reference. Furthermore, as shown in  FIGS. 2B ,  2 C, and  2 E, after passing over 45-degree turning roller  270 , adhesive layer  299  of strip section  240  is now oriented facing adhesive layer  295  of strip section  296 . 
         [0038]    Still referring to  FIGS. 2B-2F , with strip sections  240  and  296  oriented as described above, strip sections  240  and  296  then pass through a lamination section  280 . Lamination section  280  causes the adhesive layers of strip sections  240  and  296 , to join forming a multilayer adhesive laminate  285 . As shown in  FIGS. 2B and 2F , the multilayer adhesive laminate  285  has a combined adhesive layer  298  surrounded on one side by backing film  250  and one the other side by release liner  297 . It should be noted that combined adhesive layer  298  is comprised of adhesive layer  299  of strip section  240  and adhesive layer  295  of strip section  245 . 
         [0039]    Now referring to  FIG. 3A , a process is shown for manufacturing a multilayer adhesive laminate by combining a multitude of adhesive coatings between a single release liner and single backing film. At step  300 , an adhesive coating is applied to a release liner using any suitable coating method. At step  305 , the web containing the adhesive-coating and release liner is cured using any suitable method. At step  310  the web is slit into several strips using any suitable slitting method. At step  315  a backing film is attached to the adhesive layer of a first strip. From this first strip, at step  320 , the release liner is removed, thus exposing the adhesive layer of the first strip, opposite the side of the backing film. At step  323 , a second strip is then directed through the process to orient its adhesive layer such that it faces the exposed adhesive layer of the first strip. At step  325 , the adhesive layer of the second strip is laminated to the exposed adhesive layer of the first strip using any suitable lamination process. At step  330 , the release liner of the second strip is removed, thus exposing the adhesive layer of the second strip, opposite the side laminated to the first strip. At step  333 , a third strip is then directed through the process to orient its adhesive layer such that it faces the exposed adhesive layer of the second strip. At step  335 , the adhesive layer of the third strip is laminated to the exposed adhesive layer of the second strip using any suitable lamination process. At step  340 , steps  330 ,  333 , and  335  are repeated with the next available strip for lamination. However, step  340  concludes by not removing the release liner of the final laminated strip, thus forming the multilayer adhesive laminate. 
         [0040]    Referring to  FIGS. 3B-3H , a schematic shows an exemplary way to direct the strips to achieve the multilayer adhesive laminate discussed in  FIG. 3A . In  FIG. 3B , web section  345  is the adhesive coated web after curing step  305  of  FIG. 3A . Web section  345  travels through slitter section  346  where web section  345  is divided into a plurality of strip sections  347 ,  348 ,  349 ,  350 ,  351 ,  352 ,  353 , and  354 . Strip section  354  has an adhesive layer  391  on a release liner  356  as shown in  FIG. 3C . Each of strip sections  347 ,  348 ,  349 ,  351 ,  352 , and  353  have a similar adhesive layer on release liner structure as shown in  FIG. 3C  with respect to strip section  354 . 
         [0041]    Still referring to  FIGS. 3B-3H , strip section  354  travels to backing film application section  363 , where backing film  355  is attached to adhesive layer  391  of strip section  354  to produce a strip section  393  having a backing film  355 , an adhesive layer  391 , and a release liner  356  as shown in  FIG. 3D . Strip section  393  then travels to a release liner removal section  371 . Release liner  356  is removed from strip section  393  to produce strip section  394 . As shown in  FIG. 3E , strip section  394  has backing film  355  on adhesive layer  391 , which now has an exposed adhesive surface where release liner  356  was formerly positioned. 
         [0042]    Strip section  353  travels into 45-degree turning roller (shown in phantom in drawing), which causes a change in the surface orientation of strip section  353 , and causes strip section  353  to change its direction of travel by about 90-degrees.  FIG. 3B  shows that before strip section  353  passes over the 45-degree turning roller, the adhesive layer of strip section  353  faces upward (and conversely the release liner  357  faces downward). After passing over the 45-degree turning roller, the adhesive layer of strip section  353  faces downward (and conversely the release liner  357  faces upward). Strip section  353  continues into another 45-degree turning roller (shown in phantom in drawing), which again causes a change in the surface orientation of strip section  353 , and causes strip section  353  to change its direction of travel by about 90-degrees.  FIG. 3B  shows that before strip section  353  passes over the second 45-degree turning roller, the adhesive layer of strip section  353  faces downward (and conversely the release liner  357  faces upward). After passing over the second 45-degree turning roller, the adhesive layer of strip section  353  faces upward (and conversely the release liner  357  faces downward). As shown in  FIGS. 3B and 3E , the 45-degree turning rollers that guide strip section  353  are located such that, at the exit of the second 45-degree turning roller, strip section  353  aligns with strip section  394 , and strip section  353  is traveling below strip section  394  in the same direction and speed. Those of ordinary skill in the art will appreciate that heights of strip sections  353  and  394  may be manipulated by positioning turning rollers or web path guides at different heights with respect to a common plane of reference. Furthermore, after passing over the second 45-degree turning roller, the adhesive layer of strip section  353  faces the exposed adhesive layer  391  of strip section  394 . 
         [0043]    Still referring to  FIGS. 3B-3H , with strip sections  353  and  394  oriented as described above, strip sections  353  and  394  then pass through a lamination section  364 . Lamination section  364  causes the adhesive layers of strip sections  353  and  394 , to join together forming a strip section  395  as shown in  FIG. 3F . Strip section  395  has a combined adhesive layer  392  surrounded on one side by backing film  355  and on the opposite side by release liner  357 . It should be noted that combined adhesive layer  392  is comprised of adhesive layer  391  of strip section  394  and the adhesive layer of strip section  353 . 
         [0044]    Still referring to  FIGS. 3B-3H , strip section  395  then travels to a release liner removal section  372 . Release liner  357  is removed from strip section  395  to produce strip section  396 . As shown in  FIG. 3G , strip section  396  has backing film  355  on top of combined adhesive layer  392 , which now has an exposed adhesive surface where release liner  357  was formerly positioned. 
         [0045]    Strip section  352  travels into 45-degree turning roller  383 , which causes a change in the surface orientation of strip section  352 , and causes strip section  352  to change its direction of travel by about 90-degrees.  FIG. 3B  shows that before strip section  352  passes over 45-degree turning roller  383 , the adhesive layer of strip section  352  faces upward (and conversely the release liner  358  faces downward). After passing over 45-degree turning roller  383 , the adhesive layer of strip section  352  faces downward (and conversely the release liner  358  faces upward). Strip section  352  continues into another 45-degree turning roller  389 , which again causes a change in the surface orientation of strip section  352 , and causes strip section  352  to change its direction of travel by about 90-degrees.  FIG. 3B  shows that before strip section  352  passes over 45-degree turning roller  389 , the adhesive layer of strip section  352  faces downward (and conversely the release liner  358  faces upward). After passing over 45-degree turning roller  389 , the adhesive layer of strip section  352  faces upward (and conversely the release liner  358  faces downward). As shown in  FIGS. 3B and 3G , 45-degree turning rollers  383 ,  389  that guide strip section  352  are located such that, at the exit of 45-degree turning roller  389 , strip section  352  aligns with strip section  396 , and strip section  352  is traveling below strip section  396  in the same direction and speed. Those of ordinary skill in the art will appreciate that heights of strip sections  352  and  396  may be manipulated by positioning turning rollers or web path guides at different heights with respect to a common plane of reference. Furthermore, after passing over 45-degree turning roller  389 , the adhesive layer of strip section  352  faces the exposed adhesive layer  392  of strip section  396 . 
         [0046]    Still referring to  FIGS. 3B-3H , with strip sections  352  and  396  oriented as described above, strip sections  352  and  396  then pass through a lamination section  365 . Lamination section  365  causes the adhesive layers of strip sections  352  and  396 , to join forming a strip section  397  as shown in  FIG. 3H . Strip section  397  has a combined adhesive layer  398  surrounded on one side by backing film  355  and on the opposite side by release liner  358 . It should be noted that combined adhesive layer  398  is comprised of adhesive layer  392  of strip section  396  and the adhesive layer of strip section  352 . 
         [0047]    As shown in  FIGS. 3A and 3B , the process described in the preceding paragraphs repeats to achieve the desired laminate thickness. More specifically, release liner  358  of strip section  397  is removed and strip section  351  is positioned using 45-degree turning rollers for lamination. As shown in  FIG. 3B , after final strip section  347  is laminated to the intermediate product, the release liner of strip section  347  is maintained on the laminate to produce the final multilayer adhesive laminate  390  as shown in  FIGS. 3B and 3I . The final multilayer adhesive laminate  390  has a combined adhesive layer  399  surrounded on one side by backing film  355  and on the other side by release liner  400 . It should be noted that combined adhesive layer  399  is comprised of the adhesive layers of strip sections  354 ,  353 ,  352 ,  351 ,  350 ,  349 ,  348 , and  347 . 
         [0048]    While the above paragraphs have described several product features, this disclosure should not be limited to the precise features shown and described. For example, the adhesive coating disclosed may be of any of several types. For instance, the adhesive coating may be a solvent based adhesive coating for use in a transdermal or topical medical patch. In such examples, the adhesive coating may contain medicinal formulations for the treatment of certain ailments. By way of example and not limitation, to treat skin pain or discomfort, lidocaine may be combined with the adhesive to create a skin treatment patch. Those of ordinary skill in the art will appreciate that the adhesive may be combined with any suitable medicinal formulation, where topical or transdermal drug delivery is desired. 
         [0049]    Additional medical related applications for a multilayer adhesive laminate as disclosed herein may include medical tapes, wound dressings, ostomy adhesives, and numerous others. Similarly, the multilayer adhesive laminate disclosed herein, may have applications in other industries where a thick coating of pressure-sensitive adhesive is desirable; for example, applications may exist in consumer products, automotive, and home improvement industries. 
         [0050]    Some additional product features described include release liners and backing films. It should be understood that this disclosure shall encompass any variety of release liners and backing films suitable for adhering to an adhesive coating. By way of example only, release liners and backing films may be manufactured from natural or synthetic fibers that may be woven, nonwoven, melt cast, or extruded. Furthermore, a combination of natural or synthetic fibers may be used. Those of ordinary skill in the art will appreciate the variety of materials suitable for use as both release liners and backing films. 
         [0051]    The above disclosure also describes several process features, and the disclosure should not be limited to the precise process features shown or described. For example, several web-guiding structures are disclosed including 45-degree and 90-degree turning rollers. It should be understood, that in some embodiments such turning rollers may be driven or braked, while in other embodiments such turning rollers may be freely rotating. Still in other embodiments, turning rollers may be interchanged with turning or guide bars that do not rotate. Similarly, the precise degrees specified for the turning rollers are not required and maybe substituted with turning rollers having other degree configurations. 
         [0052]    Some additional process features described include coating, curing, slitting, and laminating processes. It should be understood that this disclosure is not intended to be limited to a specific method for conducting any of these processes. For example, several types of coating, curing, slitting, and laminating processes may be compatible with this disclosure. By way of example only, the adhesive coating may be accomplished in a spray application, a metered roller application, or any other suitable coating method. By way of example only, the curing process may be accomplished using a steam-filled-can drying system, a through-air drying system, a radiation curing system, or any other suitable method. By way of example only, the slitting process may be accomplished using a slitting blade that may be comprised of a metal or ceramic, a rotating slitting wheel, an air or water jet, or any other suitable slitting method. By way of example only, the laminating process may be accomplished by compressing the laminate layers between two rollers, by ultrasonic bonding, by chemical adhesion, or any other suitable laminating method. Those of ordinary skill in the art will appreciate the variety of methods suitable for use in coating, curing, slitting, and laminating. 
         [0053]    Having shown and described various embodiments, further adaptations of the methods and systems described herein may be accomplished by appropriate modifications by one of ordinary skill in the art without departing from the scope of this disclosure. Several of such potential modifications have been mentioned, and others will be apparent to those skilled in the art. For instance, the examples, embodiments, geometrics, materials, dimensions, ratios, steps, and the like discussed above are illustrative and are not required. Accordingly, the scope of the present invention should be considered in terms of whatever claims recite the invention, and is understood not to be limited to the details of structure and operation shown and described in the description.

Technology Classification (CPC): 2