Patent Publication Number: US-2020291655-A1

Title: Fastener cap for lumber wrap

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of United States Provisional Patent Application No. 62/169,842, filed on 2 Jun. 2015, and entitled “FASTENER CAP FOR LUMBER WRAP,” which application is incorporated by reference in its entirety herein, and for all purposes. 
    
    
     TECHNICAL FIELD 
     This application relates generally to protective systems for the lumber industry, and more specifically to fastener caps that can be used to secure protective wraps to lumber and other wood-based products. 
     BACKGROUND 
     Fastener caps are often used in the lumber industry to secure protective plastic sheeting or wraps to exposed loads of slumber during transportation and storage. The fastener caps are generally the same type of fastener caps used in the roofing industry to secure an overlayment, such as asphalt shingles, plastic sheeting, or metallic roof panels, to the underlying plywood of the roof deck. Roofing fastener caps are typically made from a hard plastic material that is thick enough to prevent the head or crown of a fastener from pulling through the fastener cap, and conformable enough to seal around the body of the fastener to prevent moisture from seeping into the aperture created by the fastener. In addition, when linked together as a fastener cap assembly, the roofing fastener caps can be automatically applied to the roofing surface with a fastener driving tool or nail gun. Unfortunately, however, when roofing fastener caps are used to secure protective wrap over lumber that is destined for reduction into wood pulp, the plastic caps often fall into the process intake when the lumber wrap is removed, thereby contaminating the pulp stream. 
     What is needed is a fastener cap and fastener cap assembly made from a more pulp-friendly material that will still reliably secure the protective plastic wrap to the load of lumber and prevent pull-through of the fastener head or crown, even when subjected to harsh outdoor conditions such as rain, snow, sleet and ice, and over time to UV exposure from sunlight. It is toward such a fastener cap and fastener cap assembly that the present invention disclosure is directed. 
     SUMMARY 
     Briefly described, one embodiment of the present disclosure includes a fastener cap assembly for securing protective wrap to lumber that includes a plurality of fastener caps spaced from one another by breakable tabs along a first axis extending through a center of the fastener caps, with each of the fastener caps and breakable tabs comprising a substrate formed from a paper-based material and a protective material applied to at least the top surfaces of the substrates that cures to form a non-waxy and moisture-resistant protective barrier. Both the substrate and the protective barrier are degradable within a pulp manufacturing process. 
     In another embodiment of the disclosure, a repulpable fastener cap comprises a substrate formed from dried paper-based material having a predetermined thickness and strength sufficient to secure a protective plastic wrap to a load of lumber when a fastener, such as staple or nail, is driven through the center of the fastener cap. A protective material is applied to the substrate to maintain the structural integrity of the substrate in a wet environment, with both the substrate are protective material being degradable within a pulp manufacturing process. 
     The invention will be better understood upon review of the detailed description set forth below taken in conjunction with the accompanying drawing figures, which are briefly described as follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of a fastener cap assembly, in accordance with one representative embodiment of the present disclosure. 
         FIG. 2  is a cross-sectional side view of the fastener cap assembly, as viewed from section line A-A of  FIG. 1 . 
         FIG. 3  is a cross-sectional side view of a fastener cap after attachment to a load of lumber with a staple, as viewed from section line B-B of  FIG. 1 . 
         FIG. 4  is a plan view of a fastener cap assembly, in accordance with another representative embodiment. 
         FIG. 5  is a plan view of a fastener cap assembly, in accordance with yet another representative embodiment. 
         FIG. 6  is side view of stacked fastener caps from the fastener cap assembly of  FIG. 5 . 
         FIG. 7  is a cross-sectional side view of a fastener cap after attachment to a load of lumber with a staple, in accordance with another representative embodiment. 
         FIG. 8  is a cross-sectional side view of a fastener cap after attachment to a load of lumber with a staple, in accordance with yet another representative embodiment. 
     
    
    
     Those skilled in the art will appreciate and understand that, according to common practice, various features of the drawings discussed below are not necessarily drawn to scale, and that dimensions of the various features and elements of the drawings may be expanded or reduced to more clearly illustrate the embodiments of the present disclosure described herein. 
     DETAILED DESCRIPTION 
     Generally described, the present disclosure relates to a pulp-friendly fastener cap and fastener cap assembly for securing protective plastic sheeting or wrap to a load of lumber or similar wood products. As discussed below, the fastener cap can provide significant advantages and benefits over other types of fastener caps currently used in the lumber industry. However, the recited advantages are not meant to be limiting in any way, as one skilled in the art will appreciate that other advantages may also be realized upon practicing the present disclosure. It will also be appreciated that the pulp-friendly fastener cap may not be limited only to uses relating to the lumber industry, and that other uses and applications are possible and considered to fall within the scope of the present disclosure. 
     Referring now in more detail to the drawing figures, wherein like parts are identified with like reference numerals throughout the several views,  FIG. 1  illustrates one embodiment of a fastener cap assembly  10  for providing a plurality of fastener caps to a fastener driving tool or nail/staple gun. The fastener cap assembly  10  generally comprises a plurality of fastener caps  20  that are spaced from one another along a first or centerline axis  12  that extends through the center portions  21  of the fastener caps  20 . Each fastener cap  20  can have a cap width  22  along the first axis as well as a cap length  26  along a second axis  24  that is orthogonal or perpendicular to the first axis  12 . 
     In one aspect the cap length  26  can be different than the cap width  22  to form a fastener cap having a non-round or oblong shape. As shown in  FIG. 1 , for instance, the cap length  26  can be greater than the cap width  22 , so that the second or long axes  24  of the oblong fastener caps  20  are perpendicular to the first or centerline axis  12  of the fastener cap assembly  10 . It will be appreciated that arranging the long axes  24  of the oblong fastener caps  20  perpendicular to the centerline axis  12  of the assembly can be useful for increasing the number of fastener caps  20  in any predetermined length of the fastener cap assembly  10  over other fastener cap assemblies of equal length that may be found in the prior art. Nevertheless, other configurations and arrangements, such as with the long axes of the oblong fastener caps being parallel to the first or centerline axis of the fastener cap assembly, are also contemplated and considered to fall within the scope of the present disclosure. 
     In some aspects the cap length  26  can be at least one and a half times the cap width  22  so as to maintain a desired minimum distance between the ends of the elongate crown  72  of an installed staple  70  (shown in outline) and the side edges  38  of the fastener cap  20 , such as when the staple is driven through the center portion  21  of the fastener cap  20  with the fastener driver tool described above. This can be particularly useful for increasing the surface area, and in this case the hold-down force, that is provided by the fastener cap  20  to secure a lumber wrap or sheet to a load of lumber. 
     In addition, each fastener cap  20  in the fastener cap assembly  10  can be releasably connected by one or more breakable tabs  40  to an adjacent fastener cap. For example, single breakable tabs  40  can be aligned along the first or centerline axis  12  of the fastener cap assembly  10 , as shown in  FIG. 1 , to bridge the gaps  16  between fastener caps and to connect each adjacent pair of fastener caps  20 . The breakable tabs  40  are not limited to the configuration illustrated in  FIG. 1 , however, and in other embodiments (not shown) the tabs may be offset to either side of the centerline axis in alternating fashion, or may be offset from the centerline axis in opposite directions on either side of every other fastener cap. Alternatively, sets of two breakable tabs can also be spaced from centerline axis, one in each direction, to connect each adjacent pair of fastener caps. 
     As shown in  FIG. 2 , the assembly  10  of fastener caps  20  and breakable tabs  40  can comprise a paper-based substrate  30 , such as a recycled or virgin coated paper material, having a substantially uniform thickness  32 . This can allow the fastener cap assembly  10  to be manufactured in a high-volume production process such as die cutting. In some aspects the thickness  32  of the paper-based substrate can be 24 point (0.024 inch) or 28 point (0.028 inch), while in other aspects the thickness  32  of the paper-based substrate  30  can range from about 0.018 inch to about 0.040 inch. As will be appreciated by the skilled artisan, the paper-based substrate  30  can be degraded or dissolved within the pulp manufacturing process without contaminating the pulp stream. 
     The paper-based substrate  30  can also be coated with a protective water and moisture resistant coating  50  that prevents foreign liquids or vapors from coming into direct contact with and being absorbed by the underlying substrate  30 . In one aspect the protective coating  50  can be a water, moisture, and chemical resistant over-print varnish, such as OPV 909 T MR™, that is a commercially-available coating developed for the food packaging industries by UV Technologies located in High Point, N.C. In other embodiments plant-based recyclable and water-resistant coatings that are non-petroleum based, non-waxy, and formaldehyde-free, such as a lignin-based coating material and the like, can also be used to make the outer protective layer. In addition to preventing liquids and vapors from coming into the direct contact the paper-based substrate  30 , the protective coating  50  can also provide the fastener cap  20  with additional hardness and rigidity that, in one aspect, can help prevent the crown  72  of the staple  70  (or head of a nail) from breaking through or tearing the fastener cap  20 ′ when the staple  70  (or nail) and the fastener cap  20 ′ are driven together against the protective wrap  80  that covers a load of lumber  90 , as illustrated in  FIG. 3 . Like the paper-based substrate  30  described above, the protective coating  50  can also be degraded or dissolved within the pulp manufacturing process without contaminating the pulp stream. 
     In some aspects the protective coating  50  can also include a UV protective component that protects the underlying substrate  30  from damage resulting from continued exposure to the UV rays found in sunlight. Furthermore, depending on the porosity and/or pre-coating of the substrate  30 , in one embodiment the coating  50  can be substantially absorbed into the paper prior to curing the coating material, thereby maintaining or only slightly increasing the original thickness  32  of the substrate  30 . In other embodiments the protective coating  50  can merely adhere to the exposed surfaces of the substrate  30  without substantially penetrating into the paper-based material, and subsequently cure into a hard water and moisture resistant shell having a predetermined thickness that can range, in one aspect, from about 0.002 inch to about 0.010 inch. 
     Also visible in  FIGS. 1 and 2 , the breakable tabs  40  can be formed with a perforation or groove  44  that extends across a center portion of the breakable tabs  40  and inward from the top surface  34  for a predetermined distance. The grooves  44  can be substantially perpendicular to the centerline axis  12  of the assembly  10 , as illustrated. Alternatively, the grooves can be formed at any relative to the centerline axis, including but not limited to parallel with the centerline axis. The groove  44  can weaken the paper-based substrate  30  in the region of the breakable tabs so that the fastener caps  20  can easily separate from each other when pulled and/or twisted apart manually or sheared with a fastener driver tool. In one aspect the predetermined depth of the groove  44  can be about ⅓ the total thickness  32  of the substrate  30  (or about 0.010 inch for a paper-based substrate  30  of about 0.028 inch) or more. 
     In one aspect of the present disclosure illustrated in  FIG. 2 , the protective coating  50  can be applied the top surfaces  34  and edge surfaces  38  of the paper-based substrate  30  to form a protective shell that covers the most exposed surfaces, while leaving the bottom surfaces  36  of the substrate  30  uncoated. In another aspect shown in  FIG. 3 , the protective coating  50  can be applied to all of the exposed surfaces of the paper-based substrate  30  of the fastener cap  20 ′, including the bottom surfaces  36 . 
     Furthermore, ink printing  60  ( FIG. 2 ) can be applied to any of the surfaces  35 ,  36 ,  38  of the substrate prior to application of the protective coating  50 , as desired, with the ink being absorbed into the paper-based material. In this configuration the protective coating  50  can be substantially transparent so that the ink printing  60  is visible beneath the coating  50 . In other aspects, however, the protective coating  50  can be opaque or tinted so that all of the coated surfaces have substantially the same color. Other coloring combinations for the underlying paper-based substrate  30 , the ink printing  60  and the overlying protective coating  50  are also possible and considered to fall within the scope of the present disclosure. 
     It will be appreciated that neither the fastener caps nor the fastener cap assemblies is limited to the oblong shape or configuration shown in  FIG. 1 , and instead can be formed in a wide variety of shapes and configurations. For instance,  FIG. 4  illustrates another embodiment of the fastener cap assembly  110 , with each of the fastener caps having a round shape with a cap width  122  along the first axis  112  and a cap length  126  along a second axis  124  that are substantially equal. The fastener caps  120  can be releasably connected by one or more breakable tabs  140  that bridge the gaps  116  between adjacent fastener caps, and which can also include a perforation or groove  144  that extends across a center portion of the breakable tabs  140 . 
     In other embodiments, such as the embodiment of the fastener cap assembly  210  illustrated in  FIG. 5 , the gap between adjacent fastener caps  220  may be reduced until the breakable tabs are replaced with a merged portion  240  that joins adjacent fastener caps  220 . The merged portions  240  can also include a perforation or groove  244  that extends across a center portion of the merged portion  240  to facilitate the separation of the fastener caps from each other. As shown in  FIG. 6 , the fastener caps  220  in fastener cap assembly  210  can be separated from each other and combined into a stack  230  for loading into a fastener driver tool for application to a load of lumber. In one aspect the fastener caps  220  may have slightly rough edges  248  resulting from the torn merged portions. 
     In another embodiment of the present disclosure shown in  FIG. 7 , the paper-based substrate  330  of the pulp-friendly fastener cap  320  can be impregnated with a natural or synthetic resin  350  that imbues the entire substrate  330  with water-resistant properties, so that the additional protective coating is not needed. The impregnated fastener cap  320  can have enough strength and durability to maintain its shape and prevent pull-through of the of the crown  72  of the staple  70  after exposure to rain, snow, sleet and ice, and over time to UV exposure from sunlight. In one aspect the resin can be a recyclable plant-based resin, such as PLA (polylactic acid) and the like, that is petroleum-free and formaldehyde-free, so that the fastener cap  320  can be easily broken up and dissolved during the pulp-making process. 
     Alternatively, the paper-based substrate of the pulp-friendly fastener cap can be impregnated with a repulpable wet strength resin, such as PAE (polyamide ephichlorohydrin) and the like, that allows the paper-based substrate to become saturated with moisture after exposure the elements, yet continues to provide the wet fastener cap with enough strength and durability to maintain its shape and prevent pull-through of the fastener head. 
     In yet another embodiment illustrated in  FIG. 8 , the pulp-friendly fastener cap  420  can comprise two or more plies  432 ,  434 ,  436  of paper-based substrates that are laminated together with a pulp-friendly adhesive  440 , such as a lignin-based adhesive, and the like, to form a composite laminate fastener cap substrate  430 . In addition, the various layers of the laminate substrate  430 , especially the outer layers  432 ,  436 , can be impregnated or coated or manufactured with any of the strengthening or protective materials described above. In this way one or more of the outer paper-based layers  432 ,  436  can form the protective barriers that shield one or more middle layers  434  that provide the fastener cap  420  with the desired strength and durability for preventing pull-through of the crown  72  of the staple  70 , and thereby maintaining the lumber wrap  80  securely bound to the load of lumber  90 . Since all of the materials that form the fastener cap  420  are pulp-friendly and recyclable, including the adhesive  440  used to laminate the various plies together, the entire fastener cap  420  can still be degraded or dissolved within the pulp manufacturing process without contaminating the pulp stream. 
     In summary, the pulp-friendly fastener caps and fastener cap assemblies of the present disclosure has been described in terms of preferred embodiments and methodologies considered by the inventors to represent the best mode of carrying out the invention. However, a wide variety of additions, deletions, and modification might well be made to the illustrated embodiments by skilled artisans within the scope of the invention. These and other revisions might be made by those of skill in the art without departing from the spirit and scope of the invention, which is constrained only by the following claims.