Patent Publication Number: US-2001000117-A1

Title: Tooling for articles with structured surfaces

Description:
RELATED APPLICATIONS  
     1. This is a continuation application of application Ser. No. 09/259,781 filed Mar. 1, 1999.  
    
    
     
       FIELD OF THE INVENTION  
       2. The present invention relates to the field of manufacturing articles with structured surfaces. More particularly, the present invention provides tooling for manufacturing articles with one or more structured surfaces, methods of manufacturing the tooling, and methods of using the tooling to manufacture articles with one or more structured surfaces.  
       BACKGROUND  
       3. Articles with one or more structured surfaces find a variety of uses. The articles may be provided as films that exhibit, e.g., increased surface area, structures used to provide a mechanical fastener, optical properties, etc. When these films are manufactured for use as mechanical fasteners, the protrusions that are found on the structured surface are commonly referred to as hooks. The hooks may be formed in a curved shape or they may be substantially upright stems that are deformed to include, e.g., a head in the shape of mushroom.  
       4. Mechanical fasteners are sometimes designed so that two hook strips can be used to fasten two articles together by adhering each strip to one of the articles and then interengaging the two strips. Such a mechanical fastener is shown in U.S. Pat. No. 3,192,589 (Pearson) which calls the fastener “hermaphroditic” because its headed studs have both male and female characteristics when intermeshed. The Pearson fasteners can be made by molding a base from which integral headless studs project and then heat softening the tips of the studs.  
       5. U.S. Pat. No. 5,077,870 (Melbye et al.) discloses one method of manufacturing the hook strip portion of a mechanical fastener by forcing molten material into cavities formed in a moving mold surface. The stems formed by the moving mold surface are then capped to form the desired fasteners. The cavities are formed in the mold surface by drilling. As a result, the cavities are cylindrical in shape and, although some precision can be obtained in depth, diameter and spacing between cavities, it is obtained with some difficulty and increased costs. Furthermore, damage to the mold surface typically requires that the entire mold be discarded.  
       6. U.S. Pat. No. 5,792,411 (Morris et al.) discloses a molding tool manufactured by laser machining a mold surface. Molten material is then forced into the cavities in the moving mold surface to form stems. The stems are then capped to form the desired fasteners. Because the cavities are formed by laser ablation, the cavity shape is based on the energy distribution within the laser beam used to form the cavities. Furthermore, precise control over the depth of the cavities is difficult to obtain due to variability in the material used to construct the mold, the power of the laser beam, the energy distribution within the beam, beam focus, etc.  
       7. U.S. Pat. No. 4,775,310 (Fischer) and PCT Publication No. WO 97/46129 (Lacey et al.) disclose tooling used to manufacture hook strips for a hook-and-loop style mechanical fastener. The tools are formed by a hollow drum with a water cooling jacket. A series of mold disks or alternating mold disks and spacer plates are laminated together along the length of the drum to form the desired mold cavities on the face of the roll. Disadvantages of these designs include the cost of manufacturing the mold disks with adequate precision to ensure that the mold cavities are of the same depth, length, spacing, etc. Size limitations imposed on the disks by manufacturing difficulties can, in turn, limit line speed in processes using the tools. Other disadvantages of this design include non-uniform cooling of the mold cavities, non-uniformities in the products produced by the stacked plates, etc.  
       SUMMARY OF THE INVENTION  
       8. The present invention provides tool rolls and methods of using the tool rolls to manufacture articles with one or more structured surfaces. The tool rolls include an outer surface that, when used in connection with materials of the proper viscosity or formability, can form a structured surface on an article. Because the tools are manufactured in roll-form, they can be advantageously used in continuous manufacturing processes. Alternatively, discrete articles may be processed using the tool rolls of the present invention.  
       9. By “structured surface” it is meant that a surface of the article deviates from a planar or other smooth surface. For example, the structured surface may include protrusions extending therefrom, such as stems used in connection with mechanical fasteners. Other alternative structured surfaces include, but are not limited to: continuous grooves or ridges, elongated structures, etc.  
       10. The tool rolls of the present invention are constructed of a cylindrical base roll and are wrapped with one or more continuous wires in a helical pattern. The wires are used, in essence, to form a structured surface on the tool roll that is the negative of the structured surface to be formed on the articles processed using the tool roll. In one embodiment, at least one of the wires wound around the base roll may include a plurality of voids formed therein that, when wound in helical coils about the base roll, form a plurality of mold cavities on the outer surface of the tool roll. Alternatively, the helical pattern of one or more wound wires may be used to form a continuous helical structured surface, e.g., a helical groove or grooves.  
       11. Advantages of the tool rolls include, but are not limited to the ability to replace the wire windings on the base roll if the outer surface of the tool roll becomes damaged or worn. The tool rolls may also be relatively inexpensive as compared to the cost of manufacturing tool rolls using, e.g., stacked plates or direct drilling of the mold surface.  
       12. Another advantage is the ability to control the spacing between mold cavities along the width of the roll by varying the thickness of the wire or wires wrapped around the base roll. Spacing of the mold cavities about the circumference can also be independently controlled by controlling the spacing between voids in the wire or wires wrapped around the base roll. A further advantage is that, by controlling the profile or cross-sectional shape of the wire or wires and the shape or shapes of the voids formed in the wire, variations in the shape or shapes of the mold cavities can also be achieved.  
       13. Yet another advantage of the present invention is the relatively small thermal mass of the wire or wires wrapped around the base roll in comparison to the thermal mass of the base roll. As a result, thermal control over the mold cavities can be improved, which can result in corresponding improvements in the uniformity of the products produced using the tool rolls.  
       14. As used in connection with the present invention, a “mold cavity” may be any discontinuity in an otherwise smooth or planar surface into which moldable material may flow during a molding process. In some embodiments of the present invention, the tool rolls may include mold cavities with high aspect ratios as defined below, although it should be understood that a mold cavity need not have a high aspect ratio.  
       15. In one aspect, the present invention provides a tool roll including a cylindrical base roll. A first wire including a plurality of first voids formed therein is wound in helical coils around the base roll. The plurality of first voids in the first wire form a plurality of first cavities, each cavity of the plurality of first cavities including an opening at an outer surface of the tool roll.  
       16. In another aspect, the present invention provides a method of forming a structured surface on an article using a tool roll that includes a cylindrical base roll and a first wire having a plurality of first voids formed therein. The first wire is wound in helical coils around the base roll, such that the plurality of first voids in the first wire form a plurality of first cavities. Each cavity of the plurality of first cavities forms an opening at an outer surface of the tool roll. A moldable material is contact with the outer surface of the tool roll to form the structured surface using the outer surface of the tool roll, the moldable material at least partially filling at least some of the first cavities. The structured surface thus formed is then removed from the outer surface of the tool roll, wherein the structured surface comprises a plurality of protrusions corresponding to the plurality of first cavities.  
       17. In another aspect, the present invention provides a method of forming a structured surface on an article using a tool roll that includes a cylindrical base roll and first and second wires wound in helical coils around the base roll. The helical coils of the first and second wires alternate over a width of the roll. The height of the first wire above the base roll is less than the height of the second wire above the surface of the base roll, such that a helical groove is formed on an outer surface of the tool roll. A moldable material is contacted with the outer surface of the tool roll to form a structured surface on an article using the outer surface of the tool roll, the moldable material at least partially filling at least a portion of the helical groove formed by the first and second wires. The structured surface thus formed is then removed from the tool roll and includes a series of ridges formed therein.  
       18. These and other features and advantages of the present invention are described below in connection with illustrative embodiments of the present invention.  
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     19.FIG. 1 is a plan view of one tool roll including a plurality of cavities formed therein according to the present invention.  
     20.FIG. 1A is an enlarged perspective view of a structured surface formed using a tool roll according to the present invention.  
     21.FIG. 2 is an enlarged cut-away perspective view of a portion of the surface of the tool roll of FIG. 1 illustrating the cavities formed therein.  
     22.FIG. 3A is an enlarged plan view of the surface of the tool roll of FIG. 1.  
     23.FIG. 3B is a cross-sectional view of FIG. 3A taken along line  3 B- 3 B.  
     24.FIG. 3C is a cross-sectional view of FIG. 3A taken along line  3 C- 3 C.  
     25.FIG. 4 is a plan view of another tool roll including a plurality of cavities formed therein according to the present invention.  
     26.FIG. 5 is an enlarged cut-away perspective view of a portion of the surface of the tool roll of FIG. 4 illustrating the cavities formed therein.  
     27. FIGS.  6 A- 6 E illustrate a variety of mold cavity shapes.  
     28.FIG. 7A is a plan view of a tool roll including circumferential areas with different mold cavities.  
     29.FIG. 7B is a plan view of a tool roll including a longitudinal area with different mold cavities.  
     30.FIG. 7C is a plan view of a tool roll including a logo with different mold cavities in the area of the logo.  
     31.FIGS. 8A &amp; 8B illustrate mold cavities with different depths.  
     32. FIGS.  9 A- 9 D illustrate different wire profiles for use in tool rolls according to the present invention.  
     33.FIG. 10 illustrates one method of manufacturing a tool roll according to the present invention.  
     34.FIG. 11 illustrates one method of manufacturing a high aspect topology film using a tool roll according to the present invention.  
     35.FIG. 12 is a cross-sectional view of the apparatus of FIG. 11, taken along line  12 - 12  in FIG. 11.  
     36.FIG. 13 illustrates one method of manufacturing a high aspect topology film including protrusions on both sides using two tool rolls according to the present invention.  
     37.FIG. 14 is an enlarged partial cross-sectional view of a process using another tool roll according to the present invention.  
     38.FIG. 15 is a plan view of another tool roll including elongated discontinuous helical mold cavities.  
     39.FIG. 16 is a perspective view of a film manufactured using the tool roll of FIG. 15.  
     40.FIG. 17 illustrates a void formed in a wire in connection with Example 1.  
    
    
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS OF THE INVENTION  
     41. The present invention provides tool rolls and methods of using the tool rolls to manufacture articles with one or more structured surfaces. The tool rolls include an outer surface that, when used in connection with materials of the proper viscosity or formability, can form a structured surface on an article. Because the tools are manufactured in roll-form, they can be advantageously used in continuous manufacturing processes to form e.g., films, sheets, etc. Alternatively, discrete articles may be processed using the tool rolls of the present invention.  
     42. The tool rolls of the present invention may include a plurality of cavities in their outer surfaces that, when used in connection with materials of the proper viscosity or formability, can form protrusions or structures on at least one surface of a film. Alternatively, two such rolls can be used in combination to form a film in which both major surfaces exhibit protrusions or structures.  
     43.FIG. 1 depicts one illustrative embodiment of a tool roll  10  according to the present invention including a plurality of mold cavities  30  opening into an outer surface of the tool roll  10 . FIG. 2 illustrates an enlarged partial cut-away view of the surface of the tool roll  10  of FIG. 1. The tool roll  10  preferably includes a cylindrical base roll  12  around which one or more wires are wrapped in the shape of a helical coil to produce a surface having a plurality of mold cavities  30  formed therein.  
     44. The wire or wires wrapped around the base roll  12  may be held in place by any suitable mechanism, including, but not limited to: clamps, welding, adhesives, etc. Such techniques are known in the production of, e.g., carding rolls. See, e.g., U.S. Pat. No. 4,272,865 (Schmolke).  
     45. One preferred application in which tool rolls manufactured according to the present invention such as tool roll  10  may be used is in the production of high aspect topology structured surfaces. Referring to FIG. 1A, one illustrative article  70  formed using tool roll  10  is depicted including a structured surface having a plurality of protrusions  72  formed thereon. The illustrated protrusions have a height h′ above the surface  74  of the article  70  and a minimum width w′ measured in a plane I generally parallel to the plane of the surface  74 . If the surface  74  has some curvature, the plane I is preferably oriented tangential to the surface  74  in the area of the protrusion  72 .  
     46. The protrusions  72  may have a high aspect ratio and the tool rolls according to the present invention may be particularly advantageous in the manufacturing of structured surfaces with high aspect ratio topologies. By “high aspect ratio” it is meant that the ratio of protrusion height to minimum width (h′:w′) is, e.g., at least about 0.5:1 or higher, more preferably about 1:1 or higher, and even more preferably at least about 2:1 or higher. In addition to, or in place of, high aspect ratio as defined above, it may be preferred that the protrusion or structure height h′ above the major surface of the article be, e.g., about 0.1 millimeters or more, more preferably about 0.2 millimeters or more, and even more preferably about 0.4 millimeters or more.  
     47. Where the article  70  is provided in sheet or film form, it may advantageously be used to manufacture mechanical fasteners (e.g., mushroom-type or hook-type mechanical fasteners). If the article  70  is used as a mechanical fastener, the protrusions  72  may commonly be referred to as stems, although use of that term is not intended to limit the scope of use for the articles manufactured using the present invention.  
     48. Although the articles that can be produced by tool rolls and methods of the present invention are advantageously used as mechanical fasteners, the articles may find a variety of other uses and the tool rolls and methods of using the tool rolls to manufacture articles with structured surfaces according to the present invention should not be limited to the field of mechanical fasteners. For example, the protrusions formed on the structured surface of an article according to the present invention may provide advantages in retaining adhesives or other coatings/materials by, e.g., increasing the surface area of the film. The structured surfaces formed by the tool rolls may also be useful for decorative purposes, as flow channels, drag reduction structures, abrasive backings, etc.  
     49. The helical nature of the wrapped wires is illustrated in FIG. 1. The coils are preferably oriented at a helix angle α relative to a reference line that is normal to the surface of the cylindrical tool roll  10 . As a result of the helical nature of the wrapped wires, they progress across the surface of the roll  10  from one end to the opposite end. The helix angle α is preferably rather small, e.g., about 5 degrees or less, although larger helix angles could be used. Smaller helix angles will typically result in smaller spacing between the mold cavities along the longitudinal axis  11  of the tool roll  10 .  
     50. The illustrated tool roll  10  is manufactured using a cylindrical base roll  12  around which a continuous wire  20  including a plurality of voids  26  and a spacer wire  40  are wound. The result is that alternating helical coils of wire  20  with voids  26  and spacer wire  40  are disposed over the surface of the tool roll  10 . The inner edges  22  of the wire  20  and the inner edge  44  of the spacer wire  40  are wrapped around the base roll  12  while the outer edges  22  and  42  of the wires  20  and  40 , respectively, are wound facing outward from the base roll  12 . Both the wire  20  and the spacer wire  40  preferably have rectangular cross-sections compatible with an even progression of the helical coils across the roll  10 .  
     51. The voids  26  provided in the wire  20  are formed through the full width of the wire  20  and include opposing side walls  27  and  28  and bottom  29  as seen in FIG. 2. It is preferred, but not required that each of the voids  26  be of the same size and be evenly-spaced along the length of the wire  20  to provide uniformity in the spacing of the resultant mold cavities  30 . It is further preferred that the outer edge  22  of the coils of wire  20  is even with the outer edge  42  of the spacer wire  40  such that the areas between the mold cavities  30  in the finished tool roll  10  are substantially smooth, i.e., without significant discontinuities between the wires  20  and  40 .  
     52. Alternatively, the outer edges  22  and  42  of the wires  20  and  40 , respectively, may be located at different heights above the surface of the base roll  12 . Wires  20  and  40  with different heights can impart a structure to the surface of the article being manufactured. That structure may be in the form of elongated ridges that may provide reinforcement to, e.g., the taller protrusions formed by the mold cavities and/or the article itself.  
     53. The wire  20 , including voids formed therein that provide the desired mold cavities  30  when wound around the base roll  12  as discussed above, is preferably manufactured using a wire or strip having a generally rectangular cross-section. The voids  26  are preferably provided through the thickness of the wire  20  such that each void includes only two sides  27  and  28  aligned along the length of the wire  20  and a bottom  29 . Wire  20  may be manufactured with the voids  26  or a wire with a substantially uniform profile may first be manufactured and then processed by any suitable technique or techniques to form the voids  26  therein. The suitable technique or techniques may include, but not limited to: punching, stamping, conventional machining, laser machining, electronic discharge machining, water jet machining, etching, etc. The punching of wires to provide desired shapes is known in, e.g., the carding roll industry. See, e.g., U.S. Pat. No. 4,537,096 (Hollingsworth). The wire  20  may be manufactured from any suitable material or materials, although some preferred materials include steels, more preferably medium to low carbon steels.  
     54. The mold cavities  30  illustrated in FIGS. 1 &amp; 2 have substantially uniform cross-sectional areas along their depth from the opening at the surface of the tool roll  10  to the mold cavity bottoms  29 . FIG. 3A is an enlarged plan view of a few mold cavities  30  and FIGS. 3B and 3C are cross-sectional views of the mold cavities  30  along lines  3 B- 3 B and  3 C- 3 C, respectively. The mold cavities  30  exhibit generally rectilinear tangential cross-sectional areas along their depths d. By tangential, it is meant that the cross-section is taken along a tangent to the roll  10 . By rectilinear, it is meant that the shape of the mold cavity  30  in the tangential cross-section is formed by substantially planar sides. The illustrated cavities  30  are also oriented substantially along the radius of the roll  10 , although various orientations are possible as discussed below.  
     55. Sides  27  and  28  of the mold cavities  30  may be parallel or they may be formed with a draft angle such that sides  27  and  28  are farther apart at the openings of the mold cavities  30  than at the bottoms of the mold cavities  30  or vice versa.  
     56. One advantage of the tool rolls of the present invention is the ability to precisely control the height h of the bottom  29  of the mold cavities  30  above the bottom or inner surface  24  of the wire  20 . The bottom  29  of the mold cavity  30  will typically correspond to the end of the mold cavity.  
     57. In those instances, however, where the mold cavities have non-uniform shapes, e.g., the cavities are formed in the shape of hook or other structure, the “bottom” of the mold cavity is defined as the portion of the mold cavity that is closest to the inner surface of the wire. One example of such a mold cavity is illustrated in FIG. 6C where the mold cavity  230   c  has a bottom  229   c  closest to the inner edge  224   c  of the wire  220   c . The bottom  229   c  is located at a height he above the inner edge  224   c  of the wire  220   c . Furthermore, the depth d c  of the mold cavity  230   c  is also defined by the bottom  229   c  of the mold cavity  230   c . The mold cavity  230   c  has an end  231   c  that is distinguishable from its bottom  229   c  because the mold cavity  230   c  turns away from the inner edge  224   c  of the wire  220   c.    
     58. The preferred cylindrical base rolls  12  are precision formed to have tightly controlled runouts. That precision runout, in combination with a tightly controlled height dimension h in the wires  20  can provide mold cavities  30  with substantially uniform depths d as measured from the outer surface of the roll  10 . The tolerances to which the height dimension h can be controlled will generally be relatively small and the runout of the base roll  12  can be tightly controlled, resulting in overall tight tolerance control in the finished tool roll  10 .  
     59. The mold cavities  30  can also be characterized in terms of aspect ratio as discussed above in connection with protrusions  72  on article  70  in FIG. 1A. The aspect ratio of the mold cavities  30  will be determined based on the depth d as compared to the minimum width w (see FIG. 3A) of the mold cavities, where the minimum width w is measured in a plane tangential to the surface of the base roll  12 . In other words, the aspect ratio of the mold cavities  30  is d:w and, where the tool roll  10  is to be used to manufacture articles having a structured surface with high aspect ratio topology, it may be preferred that the ratio d:w be, e.g., at least about 0.5:1 or higher, more preferably at least about 1:1 or higher, and even more preferably at least about 2:1 or higher. In addition to, or in place of, high aspect ratio as defined above, it may be preferred that the mold cavity depth d be, e.g., about 0.1 millimeters or more, more preferably about 0.2 millimeters or more, and even more preferably about 0.4 millimeters or more.  
     60.FIGS. 3B and 3C illustrate another feature of the invention, namely the addition of a plating or other coating  50  on the roll  10 . The illustrated coating  50  is located over the entire outer surface of the tool roll  10 , i.e., the areas between the mold cavities  30  as well as on the inner surface of the mold cavities  30 . Alternatively, the coating could be located only on the outer surface of the roll  10  and absent from the inner surfaces of the cavities  30 . In another alternative, the coating  50  could be located only in the cavities  30  and not on the outer surface of the roll  10 . In still another alternative, a first coating could be located in the mold cavities  30  and a second coating could be located on the outer surface of the tool roll  10 .  
     61. Although the coating  50  is illustrated as a homogenous layer, it should be understood that coating  50  may actually be a combination of one or more materials intermixed or applied in successive layers. The material or materials used in coating  50  may vary depending on the desired physical properties. Some physical properties that may be desired include, but are not limited to increased wear resistance, controlled release characteristics, controlled surface roughness, bonding between adjacent wire windings, etc. Some preferred materials may be metal platings, more particularly an electroless nickel plating, chrome, etc.  
     62. FIGS.  4  and  5  depict another illustrative embodiment of a tool roll  110  including a plurality of mold cavities  130  opening into an outer surface of the tool roll  110 . The tool roll  110  preferably includes a cylindrical base roll  112  around which one or more wires are wrapped in the shape of a helical coil to produce a surface having a plurality of mold cavities  130  formed therein.  
     63. As best illustrated in FIG. 5, the surface of the tool roll  110  can be wound with two wires  120  and  120 ′ each of the wires including voids formed therein that, when wound together, form the mold cavities  130 . One difference between the tool roll  110  and roll  10  is that instead of a spacer wire  40  with a substantially uniform cross-section, the roll  110  includes two wires that both include voids formed therein. One advantage of the design of tool roll  110  is the ability to provide higher density mold cavities  130 , i.e., reduced spacing between the mold cavities  130 .  
     64. Although the illustrated tool roll  110  is preferably provided using two wires  120  and  120 ′, it will be understood that the tool roll  110  could be produced using three or more wires. In yet another alternative, the tool roll  110  could be provided with a single wire in which case the reference numbers  120  and  120 ′ would designate alternate windings or coils of the wire. Such an embodiment may require tighter control over the dimensions of the wire  120  and the base roll  112  to prevent alignment of the mold cavities  130  formed in adjacent coils of the wire  120 . Because that control may be difficult to achieve, it may be preferable to use two or more different wires as discussed above.  
     65. FIGS.  6 A- 6 E illustrate various shapes for voids in the wires used in connection with the present invention that vary from the substantially uniform voids discussed above. One advantage of the tool rolls according to the present invention is that the voids can be formed with different shapes and/or orientations to provide mold cavities that also have different shapes and/or orientations. It will be understood that use of some of these mold cavities to produce a finished film with desired protrusions will depend on resin selections and process conditions.  
     66. The mold cavity  230   a  in FIG. 6A has a varying cross-sectional area that increases from the opening of the cavity  230   a  to the bottom  229   a . The side walls  227   a  and  228   a  are diverging in that direction. As a result, the cavity  230   a  has a tangential cross-sectional area proximate the bottom  229   a  of the cavity  230   a  that is larger than the tangential cross-sectional area at the opening of the cavity  230   a.  An additional feature illustrated in FIG. 6A is that the bottom  229   a  of the cavity  230   a  is non-planar, with the illustrated shape being curved.  
     67.FIG. 6B depicts a mold cavity  230   b  in which the side walls  227   b  and  228   b  provide the cavity  230   b  with a varying width that reaches a maximum at some point between the opening of the cavity  230   b  and the bottom  229   b  of the cavity  230   b . In the illustrated cavity  230   b , the width w″ is at a maximum near the midpoint of the depth of the cavity  230   b . If the thickness of the wire in which the cavity  230   b  is formed is constant over the depth of the cavity, then the mold cavity  230   b  can be described as having a tangential cross-sectional area at its opening that is smaller than the tangential cross-sectional area of the cavity  230   b  at some point below its opening.  
     68.FIG. 6C depicts yet another variation in the shape of the mold cavities that can be provided in tool rolls of the present invention. The illustrated mold cavity  230   c  has a curved shape in the form of a hook. Mold cavities with that shape may be used to directly form hook strips without significant additional processing. FIG. 6D illustrates a mold cavity  230   d  including a double-ended hook shape that may also be molded by tool rolls according to the present invention.  
     69.FIG. 6E depicts a variation in the orientation of mold cavities supplied in tool rolls according to the present invention. The mold cavity  230   e  is formed with an axis  231   e  that is oriented at an angle with respect to the radius r of the tool roll (not shown).  
     70.FIG. 7A illustrates a tool roll  310  in a plan view that includes areas  314  and  316  in which the mold cavities differ. In one example, areas  314  may be provided with mold cavities while areas  316  may be substantially free of mold cavities. In another example, the mold cavities in the different areas  314  and  316  may be different. The areas  314  and  316  on tool roll  310  are depicted as having a substantially uniform width and preferably also extend about the circumference of the roll  310 .  
     71. Tool rolls according to the present invention may alternatively include areas in which the mold cavities differ that are not uniformly shaped and/or that do not extend around the circumference of the roll  310 . One such variation is illustrated in FIG. 7B in which area  314 ′ is oriented along the width of the tool roll  310 ′ and surrounded on either side by areas  316 ′. As such, area  314 ′ forms a longitudinal stripe along the roll  310 ′.  
     72.FIG. 7C illustrates another tool roll  310 ″ that also includes areas  314 ″ that have either no mold cavities or mold cavities that differ in some respect from the mold cavities in area  316 ″. The areas  314 ″ can take any shape, e.g., a logo as shown. Methods of manufacturing the tool roll  310 ″ may include manufacturing a tool roll that includes uniformly shaped mold cavities distributed uniformly over its entire surface. After manufacturing the tool roll  310 ″ with uniform mold cavities, one or more portions (e.g., areas  314 ″ ) of the surface of the tool roll  310 ″ can be masked while the other portion or portions (e.g., area  316 ″ ) is processed to differentiate the mold cavities within the areas  314 ″ from the mold cavities within the area  316 ″. One method of processing the tool roll  310 ″ could include, e.g., filling the mold cavities in the unmasked area either partially or completely. The materials used for filling could include solder, plastics, wax, etc. The materials used could be permanently located within the mold cavities or they may be removable to allow reuse of the tool roll with, e.g., a different logo.  
     73. Examples of different mold cavities  330   a  and  330   b  are illustrated in FIGS. 8A and 8B in which the depths of the mold cavities  330   a  and  330   b  are different. The mold cavity  330   a  has a depth d a  that is greater than the depth d b  of the mold cavity  330   b . Although a difference in depth is illustrated, other variations may be provided in place of or in addition to depth variations, e.g., variations in shape, cross-sectional size, orientation, etc. as discussed above. Furthermore, the mold cavities within each area  314  and/or  316  may have uniform shape, spacing, size, depth and orientation or one or more of those characteristics may vary within the area.  
     74. FIGS.  9 A- 9 D illustrate more variations in the wires used to form the mold cavities in the tool rolls of the present invention. The cross-sections are taken transverse to the lengths of the wires and, in FIG. 9A, the wire  420   a  is provided with a reverse L-shaped cross-section while the spacer wire  440   a  fits within the space formed between abutting wires  420   a.    
     75. In FIG. 9B the wires  420   b  and  440   b  have mating profiles. In addition, wires  440   b  include a non-planar surface  442   b  that, in the illustrated embodiment, is a curved surface. Where the wires  420   b  include voids that form the desired mold cavities (not shown), the addition of a curvature to the outer surface  442   b  of wires  440   b  may produce a corresponding fillet on two sides of the base of the each protrusion formed by the mold cavities. That fillet may improve the strength of the protrusion, i.e., increase its resistance to deflection. In addition, the curvature may also produce a ridged structure between protrusions that may impart additional rigidity to the film or article.  
     76. Wires  420   c  and  440   c  in FIG. 9C illustrate wires with mating profiles that also include tapered sides. FIG. 9D illustrates wires  420   d  and  440   d  that have nested profiles.  
     77. Using a wire or wires that include mating or nesting profiles as illustrated in FIGS.  9 A- 9 D may improve the integrity of the windings on the base roll as the finished tool rolls are subjected to stresses during manufacture and use as a molding tool. Many other variations in the wire profiles may be envisioned within the scope of the present invention.  
     78.FIG. 10 illustrates one process of winding a base roll  512  with a wire  420  including voids  526  and a spacer wire  540  to provide a tool roll  510  including a plurality of mold cavities  530 . It will be understood that more than two wires may be wound together if so desired.  
     79. In the methods of manufacturing tool rolls according to the present invention, it may be desirable to machine the outer surface of the tool roll  510  after winding the wires  520  and  540  to provide improved runout in the finished tool roll  510 . Because the preferred wire  520  includes voids  526  formed with a fixed height above the inner edge  524  of the wire (see FIGS.  1 - 3 C and accompanying description above), machining the outer surface of the tool roll  510  after winding may improve uniformity in the depth of the mold cavities  530 .  
     80. It may also be desirable to remove any burrs remaining from, e.g., wire punching and/or machining of the wound roll, by blasting the roll with sodium bicarbonate (baking soda) or a similar material. The finished tool roll  510  may also be processed to provide a desired surface finish within the mold cavities  530  and/or on the outer surface of the tool roll  510  between the mold cavities  530 . For example, it may be desirable to chemically etch, sandblast, plate, coat or otherwise modify the surfaces of the tool roll  510 .  
     81.FIG. 11 illustrates one process in which a tool roll  610  according to the present invention can be used to form a high aspect topology film. A moldable material  660  can be applied to the surface of the tool roll  610  by, e.g., extrusion or cast molding to create a film  670  including protrusions  672  that are replicas of the mold cavities in the tool roll  610 . In preferred embodiments, adhesion of the material  660  to the tool roll  610  is less than the cohesion within the material  660  at the time of removal from the tool roll  610 . It may be further preferred that the adhesion of the material  660  to the tool roll not exceed the tensile strength of the wire or wires used to form the tool roll  610 .  
     82. Substantially any moldable material may be used in connection with the present invention. It may be preferred that the moldable material be an orientable thermoplastic resin. Orientable thermoplastic resins that can be extrusion molded and should be useful include polyesters such as poly(ethylene terephthalate), polyamides such as nylon, poly(styreneacrylonitrile), poly(acrylonitrile-butadiene-styrene), polyolefins such as polypropylene, and plasticized polyvinyl chloride. One preferred thermoplastic resin is an impact copolymer of polypropylene and polyethylene containing 17.5% polyethylene and having a melt flow index of 30, that is available as SRD7-587 from Union Carbide, Danbury, Conn. The thermoplastic resin may also comprise blends, including polyethylene and polypropylene blends, co-polymers, such as polypropylene-polyethylene co-polymers, or coextruded as multiple layers or in alternating zones. Additives such as plasticizers, fillers, pigments, dyes, anti-oxidants, release agents, and the like may also be incorporated into the moldable material.  
     83. In one preferred process, the material  660  is provided by extrusion into a nip formed by the tool roll  610  and a backup roll  680 . The backup roll  680  preferably provides some pressure to assist in forcing the moldable material  660  into the mold cavities  630  (see FIG.  12 ) provided in the tool roll  610 . Alternatively, the backup roll  680  may be replaced by any continuously moving surface that can assist in forcing the mold material into the mold cavities in tool roll  610 .  
     84. The interior of the tool roll  610  may be supplied with a vacuum to assist in removal of air that may otherwise interfere with complete filling of the mold cavities. However, in many instances, no vacuum may be supplied as the air within the mold cavities escapes between the wires used to manufacture the tool roll  610 . In other words, the process may be performed in the absence of a vacuum.  
     85. It may also be desirable to provide some thermal control in either or both of the tool roll  610  and the backup roll  680 . Depending on process conditions, temperatures of the moldable material  660 , properties of the moldable material  660 , etc. it may be desirable to either heat one or both of the rolls  610  and  680 , cool one or both of the rolls  610  and  680 , or heat one of the rolls and cool the other roll.  
     86. After the material  660  is forced within the mold cavities in tool roll  610  and has sufficiently cooled to form a film  670  with protrusions  672  that can maintain the desired shape or shapes, it is stripped from the tool roll  610  for further processing or the film  670  can be wound into rolls. For example, if mechanical fastener strips are desired, the film  674  may be directed into a station or stations to modify the protrusions, coat adhesives, and perform other processing as discussed in, e.g., U.S. Pat. Nos. 5,845,375 (Miller et al.), 5,077,870 (Melbye et al.), PCT Publication Nos. WO 98/57565; WO 98/57564; WO 98/30381; and WO 98/14086.  
     87. It may be desirable to direct one or more additional materials into the nip formed by the tool roll  610  and backup roll  680  to provide desired additional properties to the film  670 . For example, a woven or nonwoven web may be directed into the nip. Alternatively, the film  670  may be laminated to one or more additional layers by, e.g., heat, adhesives, coextrusion, etc.  
     88.FIG. 12 is a cross-sectional view of the apparatus of FIG. 11 taken along line  12 - 12  in FIG. 11. The tool roll  610  includes mold cavities  630  filled by the moldable material to form protrusions  672  on film  670 . Also illustrated in FIG. 12 are two raised structures  682  formed on the backup roll  680 . One advantage of the raised structures  682  on the illustrated backup roll  680  is that each of the raised structures may create a line or zone of weakness along which the film  670  can be separated. The raised structures  682  are, however, optional and need not be provided in connection with the present invention.  
     89. Another optional feature that may be incorporated into the backup roll  680  is the addition of some structure to the surface of the roll  680  to increase its surface area. The increased surface area on the backup roll  680  can increase the surface area on the film  670 , thereby improving adhesion of any adhesives provided on the back side  674  of the film  670 . One example of useful structure could be a micro-embossed pattern of linear prisms on the scale of about 400 lines per inch (160 lines per centimeter).  
     90.FIG. 13 illustrates another process using wire-wound tool rolls with mold cavities formed therein. The illustrated process forms a film  770  having protrusions  772  extending from one side thereof and protrusions  772 ′ extending from the opposite side of the film  770 . The two-sided film  770  is formed by opposing tool rolls  710  and  710 ′, both of which include mold cavities formed therein. The protrusions  772  and  772 ′ may have the same characteristics in terms of size, shape, orientation, etc. or they may be different.  
     91.FIG. 14 is an enlarged cross-sectional view of the interface of another tool roll  810  with a backup roll  880 . Film  870  is located between the two rolls  810  and  880  and one surface of the film  870  is formed with a series of substantially continuous ridges formed thereon that are essentially negative images of the structure on the tool roll  810 .  
     92. Tool roll  810  is formed by wires  820  and  840  which are helically wound around a base roll  812 . Wire  840  has a taller profile than the other wire  820 , resulting in a tool roll  810  on which grooves are formed between windings of wire  840 . Although wires  820  and  840  are disclosed as having generally rectangular profiles, they could alternately be provided with a different shape, in which case the film  870  would also be formed with a different shape than that illustrated in FIG. 14. Furthermore, it will be understood that two tool rolls could be used in a process similar to that depicted in FIG. 13 to form a film with structures or protrusions on both major sides of the film.  
     93. Although the grooves formed by the wires  820  and  840  wrapped around the tool roll  810  of FIG. 14 may be continuous around the circumference of the roll  810 , they may also be discontinuous. FIG. 15 is a plan view of a tool roll  810 ′ including mold cavities  830 ′ that extend for some length around the tool roll  810 ′, but are not formed in a continuous helical groove as discussed above with respect to FIG. 14. The elongated mold cavities  830 ′ can be formed by wires including voids formed therein as discussed above. The voids in the wires used in roll  810 ′ will, however, extend for longer distances over the length of the wires.  
     94. These elongated voids may be uniformly sized and spaced as depicted in the tool rolls above, or they may be non-uniformly sized and non-uniformly spaced. Tool roll  810 ′ illustrates a wire with non-uniformly sized and spaced voids that, when wrapped around a base roll, forms non-uniformly sized and spaced mold cavities  830 ′.  
     95. The film produced by a roll such as tool roll  810 ′ will include elongated protrusions  872 ′ as illustrated in FIG. 16. Because the mold cavities  830 ′ in roll  810 ′ are non-uniformly sized and spaced, the elongated protrusions  872 ′ are also non-uniformly sized and spaced.  
     EXAMPLES  
     96. At least some of the advantages of the invention are illustrated by the following example. However, the particular materials and amounts thereof recited in these example, as well as other conditions and details, are to be interpreted to apply broadly in the art and should not be construed to unduly limit the invention.  
     97. A wire-wound tool roll was produced using a 0.007 inch by 0.059 inch (0.178 millimeter (mm) by 1.49 mm) continuous rectangular wire ribbon. The ribbon was wire punched by Hollingsworth on Wheels, Inc., Greenville, S.C. FIG. 17 depicts the general shape of the voids  926  punched into the wire  920 . The voids  926  were punched at a spacing of forty voids  926  per inch (about 16 voids per centimeter) along the length of the wire. The width w of the opening was approximately 0.0068 inches (0.172 mm). The sides  927  and  928  of the void  926  were formed with an angle φ of about 97 degrees as measured from the top surface  922  of the wire  920 . The overall depth d″ of the voids  926  as seen in FIG. 17 was approximately 0.0215 inches (0.546 mm).  
     98. The wire  920  was then wound with a spacer wire having a rectangular profile of 0.018 inches by 0.059 inches (0.457 mm by 1.49 mm). The base roll on which the wires were wound had a 12 inch diameter (305 mm) and a face that was 14 inches wide (356 mm). The winding was also performed by Hollingsworth on Wheels, Inc. using known carding roll industry techniques.  
     99. The wound tool roll was then located in an extrusion take-away as depicted in, e.g., FIG. 11, with a backup roll to force resin into the mold cavities. The backup roll was silicone coated with a durometer hardness of 55.  
     100. A 2 inch (50.8 mm) single screw extruder was used in connection with a 14 inch wide (356 mm) slot die. The resin used was SRD7-587 thermoplastic polypropylene available from Union Carbide Company, Danbury, Conn.  
     101. The resin was extruded from the die at a temperature of 450 degrees Fahrenheit (232 degrees Celsius) into the nip takeaway formed by the tool roll and silicone backup roll which were operating at a speed of 35 feet per minute (10.6 meters per minute) and a nip pressure of 60 pounds per linear inch (105 Newtons per centimeter (N/cm)). Complete filling of the mold cavities was obtained with a peel force for the formed film of about 2.5 pounds per linear inch (4.4 N/cm) for a 10 inch wide (254 mm) web.  
     102. The base roll used to manufacture the tool roll was a chill roll and the surface temperature of the tool roll was maintained between 105 and 110 degrees Fahrenheit (40.5 degrees Celsius and 43.3 degrees Celsius) while the surface temperature of the backup roll was maintained at about 150 degrees Fahrenheit (65 degrees Celsius).  
     103. Using the above process conditions, a high aspect topology film was produced with a basis weight of 150 grams per square meter. The film from which the protrusions extends had a thickness of about 110 micrometers.  
     104. All patents, patent applications, and publications cited herein are each incorporated herein by reference in their entirety, as if individually incorporated by reference. Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the scope of this invention, and it should be understood that this invention is not to be unduly limited to the illustrative embodiments set forth herein.