Patent Publication Number: US-2011072752-A1

Title: Shingle with increased thickness of sealant

Description:
BACKGROUND 
     Typical asphalt-based roofing shingles include a roofing mat with asphalt and covered with a layer of roofing granules. The shingles include a prime portion that is exposed when the shingles are installed on a roof and a headlap portion that is covered by the upper adjacent course of shingles when the shingles are installed on a roof. Laminated roofing shingles also include an underlay made from a second asphalt-coated mat and positioned beneath the prime portion of the shingles. 
     A common type of laminated shingle includes an overlay having tabs and cutouts in the exposed portion of the shingle, and an underlay adhered to the bottom of the overlay below the tabs and cutouts. The laminated shingle includes laminated or double-layered portions where the overlay and underlay overlap, and non-laminated or single-layered portions where they do not overlap. The laminated portions include the areas of the tabs, and a longitudinal central area of the shingle between the inner ends of the cutouts and the inner end of the underlay. The non-laminated portions include the area of the shingle that does not include the underlay. 
     Asphalt shingles generally include a sealant bead to hold down the tabs of the shingle when the shingles are installed on a roof. The tab sealant can be positioned on the top of the shingle for bonding to the tab of the next overlying shingle, or can be positioned beneath the tab portion of the shingle to bond the tab portion to a shingle in the previously laid course of shingles. 
     Subsequent to manufacturing the roofing shingles, the laminated shingles are packaged in a stack or bundle of shingles. The laminated shingles are generally stacked back to back by turning every other shingle 180° relative to the adjacent shingles. This stacking method generally minimizes uneven build in the bundle caused by the difference in thickness between the area of the shingle that includes the underlay and the area that does not include the underlay. In some instances, the pressure is exerted on the tab sealant in the pallet, because the tab sealant becomes the high point. This pressure can cause the sealant to be flattened, thereby lessening the effectiveness of the tab sealant to hold down the shingle tabs when the shingles are installed on the roof. 
     It would be desirable to have an improved shingle and process for making the shingle. 
     SUMMARY 
     In accordance with embodiments of this invention there are provided roofing shingles having a headlap portion, a tab portion, a granulated top surface and a bottom surface. The bottom surface of the shingles includes a bead of tab sealant extending horizontally across the shingles when the shingles are applied to a roof. The tab sealant has a thickness that causes the tab sealant to extend beyond a face of the bottom surface, and is configured to bond to an underlying shingle when the shingles are applied on a roof with other similar shingles in courses. The granulated top surface has a depression in the headlap portion extending horizontally across the shingles when the shingles are applied to the roof. The depression is spaced from a top edge of the shingles by a distance that will allow the depression to be aligned with the tab sealant of complementary shingles when the shingles are assembled in complementary pairs, back to back in a bundle. 
     In accordance with other embodiments, there are also provided roofing shingles having a headlap portion, a tab portion, a granulated top surface and a bottom surface. The bottom surface of the shingles includes a bead of tab sealant extending horizontally across the shingles when the shingles are applied to a roof. The tab sealant has a thickness that causes the tab sealant to extend beyond a face of the bottom surface, and is configured to bond to an underlying shingle when the shingles are applied on a roof with other similar shingles in courses. The granulated top surface has a depression in the headlap portion extending horizontally across the shingles when the shingles are applied to the roof. The depression is formed of fine granules having a diameter smaller than a remainder of the granules of the granulated top surface. 
     In accordance with other embodiments, there are also provided methods for packaging roofing shingles in a bundle. The methods include the steps of making shingles having a headlap portion, a tab portion, a granulated top surface, a bottom surface, and a depression, and further including a bead of tab sealant on the bottom surface, wherein the depression and tab sealant extend horizontally across the shingles when the shingles are applied to a roof. The methods further include assembling the shingles in complementary pairs back to back in a bundle, wherein the depression of each shingle is aligned with the tab sealant of its complementary shingle in the bundle. 
     In accordance with other embodiments, there are also provided methods for making roofing shingles having a headlap portion, a tab portion, a granulated top surface, a bottom surface, and a bead of tab sealant which extends horizontally across the shingles when the shingles are applied to a roof. The methods include applying asphalt to a shingle mat to form an asphalt-coated sheet. The methods further include applying fine granules to a portion of the asphalt-coated sheet, the portion being configured to extend horizontally across the shingle when the asphalt-coated sheet is made into a shingle and the shingle is installed on a roof. The methods further include applying headlap and prime granules to a remainder of the asphalt-coated sheet, thereby forming the granulated top surface, the headlap and prime granules being larger in diameter than the fine granules, thereby forming a depression in the granulated top surface at the portion of the asphalt-coated sheet having the fine granules. 
     In accordance with embodiments of this invention there are provided roofing shingles having a headlap portion, a tab portion, a granulated top surface and a bottom surface. The bottom surface of the shingle includes a bead of tab sealant extending horizontally across the shingle when the shingle is applied to a roof. The tab sealant has a thickness that causes the tab sealant to extend beyond a face of the bottom surface, and is configured to bond to an underlying shingle when the shingle is applied on a roof with other similar shingles in courses. The bottom surface has a depression in the headlap portion extending horizontally across the shingle when the shingle is applied to the roof. The depression is spaced from a top edge of the shingles by a distance that will allow the depression to be aligned with the tab sealant of a complementary shingle when the shingles are assembled in complementary pairs, back to back in a bundle. 
     Various advantages of this invention will become apparent to those skilled in the art from the following detailed description of the invention, when read in light of the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view in elevation of an apparatus for manufacturing asphalt-based roofing shingles according to an embodiment of the invention. 
         FIG. 2  A is a side view of a complementary pair of laminated roofing shingles showing the alignment of tab sealants with depressions formed of fine granules in the headlap portion of the granulated top surface. 
         FIG. 2B  is an enlarged view of the shingle of  FIG. 2A . 
         FIG. 3  is a side view of a complementary pair of laminated roofing shingles showing the alignment of tab sealants with depressions formed on the bottom surface underneath the headlap portion according to an embodiment of the invention. 
         FIG. 4  is a schematic top view of a granule applicator making two-wide shingles having portions of fine granules deposited on the headlap portion of the shingles. 
         FIG. 5  is a cross-sectional, enlarged view of the rollers shown in  FIG. 1  used to create a depression according to embodiments of the invention. 
         FIG. 6  is a side cross-sectional view of a bundle of laminated roofing shingles according to embodiments of the invention stacked back to back showing the alignment of the depressions with the tab sealants of the complementary shingles to reduce pressure exerted on the tab sealants in the bundle. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention will now be described with occasional reference to the specific embodiments of the invention. This invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. 
     Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for describing particular embodiments only and is not intended to be limiting of the invention. As used in the description of the invention and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     Unless otherwise indicated, all numbers expressing quantities of dimensions such as length, width, height, and so forth as used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless otherwise indicated, the numerical properties set forth in the specification and claims are approximations that may vary depending on the desired properties sought to be obtained in embodiments of the present invention. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical values, however, inherently contain certain errors necessarily resulting from error found in their respective measurements. 
     In accordance with embodiments of the present invention, roofing shingles specially configured to enable the tab sealant to maintain its thickness and height and not flatten out when the shingles are assembled in complementary pairs, back to back in a bundle, are provided. Also, methods for packaging roofing shingles in a bundle so that the sealant bead maintains its thickness and height and does not flatten out when the shingles are assembled in complementary pairs, back to back in a bundle, are provided. In a particular embodiment, the use of fine granules in a stripe on the granulated surface of the headlap portion opposite the release surface provides about 15-20 mils of reduced thickness for the tab sealant on the complementary shingle in the bundle, thereby reducing compression or spreading of the sealant bead. It is contemplated that this results in an increase of the sealant thickness at installation and improves bonding of the sealant to the underlying shingle in the previous course of shingles on the roof. It will be understood the term “alignment” refers to the tab sealant and depression being aligned within 10 mm of each other when the shingles are assembled in complementary pairs, back to back in a bundle. Alternatively, the term “alignment” refers to the vertical alignment of the tab sealant and depression at their respective center points when the shingles are assembled in complementary pairs, back to back in a bundle. The term “granules” as used herein, is defined to mean fine, headlap and prime granules unless otherwise specified. The term “asphalt coating”, as used herein, is defined to mean any type of material appropriate for coating a roofing material, including, but not limited to bituminous materials including asphalts, tars, pitches, and mixtures thereof. The term “depression” as used herein, is defined to mean any groove, indentation, recess, and the like, that assists the sealant bead to maintain its thickness and height when the shingles are assembled in complementary pairs, back to back in a bundle. The term “mat”, as used herein, is defined to mean any type of material known for use in reinforcing asphalt-based roofing materials, including, but not limited to a web, scrim or felt of fibrous materials such as mineral fibers, cellulose fibers, rag fibers, mixtures of mineral and synthetic fibers, and the like. 
     The description and figures disclose roofing shingles configured in such a manner so that the sealant bead is more likely to maintain a significant portion of its thickness and height when the shingles are packaged in a bundle. Such a sealant bead will have less of a tendency to flatten out when the shingles are assembled in complementary pairs, back to back in a bundle. Further disclosed are methods for packaging roofing shingles in a bundle so that the sealant bead maintains its thickness and height and flattens out less when the shingles are assembled in complementary pairs, back to back in a bundle. Further disclosed are methods for making roofing shingles configured in such a manner so that the sealant bead is more likely to maintain a significant portion of its thickness and height when the shingles are packaged in a bundle. For ease of discussion herein, the prime region of the roofing shingles will be generally referred to as the tab portion. 
     Composite shingles, such as asphalt shingles, are a commonly used roofing product. Asphalt shingle production generally includes feeding a base material from an upstream roll and coating it first with a filled roofing asphalt material, then a layer of granules. The base material may be made from a fiberglass mat provided in a continuous sheet. It should be understood that the base material can be any suitable support material. 
     The filled roofing asphalt material is added to the continuous shingle membrane for strength and improved weathering characteristics. It should be understood that the filled roofing asphalt material can include any suitable material, preferably low in cost, durable, and resistant to fire. 
     The granules deposited on the composite material shield the filled roofing asphalt material from direct sunlight, offer resistance to fire, and provide texture and color to the shingle. The granules generally involve at least two different types of granules. Headlap granules are applied to the headlap portion. Headlap granules are relatively low in cost and primarily serve the functional purposes of protecting the underlying asphalt material, balancing sheet weight and preventing overlapping shingles from sticking to one another. Colored granules or other prime granules are relatively expensive and are applied to the shingle at the prime (or tab) portions. Prime granules are disposed upon the asphalt strip for both the functional purpose of protecting the underlying asphalt strip and for the purpose of providing an aesthetically pleasing appearance of the roof. 
     The layers of granules are generally applied with one or more granule applicators, such as granule valves, known in the art. The granules can be applied to the continuous shingle membrane in color patterns to provide the shingles with an aesthetically pleasing appearance. The granules optionally can include anti-microorganism granules, such as copper granules, to inhibit the growth of algae, fungus, and/or other microorganisms. 
     Referring now to the drawings, there is shown in  FIG. 1  an apparatus  10  for manufacturing asphalt-based roofing shingles used in accordance with the invention. The illustrated manufacturing process involves passing a continuous sheet in a machine direction (indicated by an arrow  12 ) through a series of manufacturing operations. The sheet usually moves at a speed from about 300 feet/minute to about 800 feet/minute. However, other speeds can be used. 
     In a first step of the manufacturing process, a continuous sheet of shingle mat  14  is payed out from a roll (not shown). The shingle mat  14  can be any type of substrate known for use in reinforcing asphalt-based roofing shingles, such as a nonwoven web of glass fibers. The shingle mat  14  is fed through a coater  16  where a coating of asphalt  18  is applied to the shingle mat  14 . The asphalt coating  18  can be applied in any suitable manner. In the illustrated embodiment, the shingle mat  14  contacts a supply of hot, melted asphalt  18  to completely cover the shingle mat  14  with a tacky coating of asphalt  18 . However, in other embodiments, the asphalt coating  18  could be sprayed on, rolled on, or applied to the shingle mat  14  by other means. The asphalt can be either manufactured asphalt produced by refining petroleum or naturally occurring asphalt. The asphalt coating can include various additives and/or modifiers, such as inorganic fillers or mineral stabilizers, organic materials such as polymers, recycled streams, or ground tire rubber. Generally the filled roofing asphalt material is highly filled with a ground mineral filler material, amounting to at least about 60 percent by weight of the asphalt/filler combination. The shingle mat  14  exits the coater  16  as an asphalt-coated sheet  20 . The asphalt coating  18  on the asphalt-coated sheet  20  remains hot and sticky. 
     As illustrated in  FIG. 1 , the resulting asphalt-coated sheet  20  is then passed beneath a series of granule applicators  34  and  36  for dispensing granules to an upper surface of the sheet  20 . The granule applicators  34  and  36  can be of any type suitable for depositing granules onto the sheet  20 . An example is a granule valve such as the granule valve disclosed in U.S. Pat. No. 6,610,147 to Aschenbeck, which is incorporated by reference in its entirety. Although two granule applicators  34  and  36  are shown in the embodiment illustrated in  FIG. 1 , any suitable number and configuration of granule applicators can be used. 
     For example, a series of two applicators can be used, wherein granule applicator  34  can be used to deposit prime granules  38  on the prime portion  30 , and granule applicator  36  can be used to apply headlap granules  40  on the headlap portion  28 . Applying prime granules  38  and headlap granules  40  produces a granule-covered sheet  42 . In another embodiment, additional granule applicators can be used for additional granule drops, such as different colors, sharp demarcations, shadow lines, and background granules. 
     As shown in  FIG. 1 , after all the granules are deposited on the asphalt-coated sheet  20 , the granule-covered sheet  42  is turned around a slate drum  44  to press the granules into the asphalt coating and to temporarily invert the granule-covered sheet  42  so that the excess granules fall off. The excess granules are recovered and applied as background granules  46  to add to the asphalt-coated sheet  20 . The granule-covered sheet  42  is subsequently fed through a cooling section  47  for cooling the sheet  42 . Subsequently, the sheet is fed through apparatus to be cut into individual shingles and then the shingles are stacked and packaged into bundles. Such apparatus is well known in the art. 
     The following description describes a laminated shingle. However, as will be appreciated by one skilled in the art, the apparatus shown in  FIG. 1  for manufacturing an asphalt-based roofing shingle can be applied to either a conventional three-tab strip shingle or a laminated shingle, i.e., the headlap portion of the laminate shingle may be thinner than the tab portion. It is to be understood that, although the invention will be illustrated with reference to a particular type of laminated roofing shingle, the invention is also applicable to other types of laminated roofing shingles, and can also be used with single layer shingles, such as 3-tab shingles. 
     A bead of tab sealant  48 ,  78  (shown on a laminated shingle  32 ,  68  in  FIGS. 2A and 3 ) is generally applied on the bottom of the shingle  32 ,  68  to hold down the tabs of the shingle when the shingles are installed on a roof. The tab sealant  48 ,  78  can be any material suitable for such purpose, but it is generally a modified asphalt material. Tab sealants are well known in the art. The tab sealant  48 ,  78  can be applied in a discontinuous or continuous manner, and in any suitable configuration. When the shingles are stacked in a bundle, the surface having the tab sealant is mated with a release surface  50 ,  82  (shown opposite to tab sealant in  FIGS. 2A and 3 ) on the complementary shingle or mating shingle in the bundle. The release surface  50 ,  82  can be any type of material suitable for covering the tab sealant  48 ,  78  (prior to installation), including, but not limited to a coating, film or strip fabricated from paper, plastic, polymers, silicone or the like. 
     In one embodiment of the invention shown in  FIG. 2A , a roofing shingle  32  includes a headlap portion  28 , a tab portion  30 , a granulated top surface  52 , an underlay  29 , and a bottom surface  54 . The bottom surface  54  of the shingle includes a bead of tab sealant  48  extending horizontally across the shingle  32  when the shingle is applied to a roof (not shown). The tab sealant  48  has a thickness that causes the tab sealant to extend beyond a face of the bottom surface  54  and is configured to bond to an underlying shingle (as described above) when the shingle is applied on a roof with other similar shingles in courses. The granulated top surface  52  has a depression  56  formed in the headlap portion  28  extending horizontally across the shingle  32  when the shingle is applied to the roof. The depression  56  is spaced from a top edge  58  of the shingle  32  by a distance D (indicated by double arrows) that will allow the depression to be aligned with the tab sealant  48  of a complementary shingle when the shingles are assembled in complementary pairs, back to back in a bundle, such as bundle  92  shown in  FIG. 6 . 
     In  FIG. 2A , a complementary pair of laminated roofing shingles  32  is shown positioned spaced apart to illustrate the alignment  22  of the tab sealant  48  with the depression  56  formed of fine granules  60  in the headlap portion  28  of the granulated top surface  52  of the laminated roofing shingles. 
       FIG. 2B  is an enlarged view of the shingle of  FIG. 2A  showing the depression  56  formed of fine granules  60 . Even though the tab sealant bead  48  does not actually touch the depression  56  or nest in the depression, the overall effect of the depression, being aligned with the tab sealant bead of the complementary shingle, is to provide protection against substantial flattening of the bead when the shingles are packaged in a bundle. The overall lessening of the thickness of the shingle by virtue of the depression  56 , acts to prevent undue pressure on the tab sealant bead  48 . 
     As shown in  FIG. 2B , the depression  56  is formed of fine granules  60  having a smaller diameter than the remainder of the granules (i.e., prime granules  38  and headlap granules  40 ) of the granulated top surface  52 . In one embodiment, the fine granules  60  have a diameter within a range of from about 0.015 inch to about 0.033 inch and the remainder of the granules has a diameter within a range of from about 0.015 inch to about 0.080 inch. It is contemplated that the middle 95% of the granule weight of the headlap and prime granules is from particles having a diameter within a range of from about 0.022 inch to about 0.068 inch. 
     For all the embodiments disclosed herein, it should be understood that the depression can be any size and shape, width and depth, suitable for reducing the flattening of the tab sealant  48 ,  78 . In one embodiment, the depression  56  has a depth  62  within a range of from about 0.05 inch to about 0.50 inch and a width  64  within a range of from about 0.25 inch to about 1.50 inch. The aforementioned dimensions are applicable to the other embodiments discussed below. 
     It is contemplated that the tab sealant  48  is spaced from a bottom edge  66  of the shingle  32  by a distance D within a range of from about 0.25 inch to about 1.00 inch. The depression  56  can be spaced from the top edge  58  of the shingle  32  by a similar distance. 
     In another embodiment of the invention shown in  FIG. 3 , a roofing shingle  68  includes a headlap portion  70 , a tab portion  72 , an underlay  71 , a granulated top surface  74 , and a bottom surface  76 . The bottom surface  76  of the shingle  68  includes a bead  78  of tab sealant extending horizontally across the shingle  68  when the shingle is applied to a roof (not shown). The tab sealant  78  has a thickness that causes it to extend beyond a face of the bottom surface  76  and is configured to bond to an underlying shingle (as described above) when the shingle is applied on a roof with other similar shingles in courses. The bottom surface  76  includes a depression  80  underneath the headlap portion  70  extending horizontally across the shingle  68  when the shingle is applied to the roof. The depression  80  is spaced from a bottom edge of the shingle by a distance D that will allow the depression to be aligned  24  with the tab sealant  78  of a complementary shingle when the shingles are assembled in complementary pairs, back to back in a bundle. In this embodiment, the depressions  80  have a release surface  82  applied to them to prevent sticking when the shingles are assembled in complementary pairs, back to back in a bundle. 
     It is contemplated that the tab sealant  78  is spaced from a bottom edge  84  of the shingle  68  by a distance D within a range of from about 0.25 inch to about 1.00 inch. The depression  80  can be spaced from the bottom edge  86  of the shingle  68  by a similar distance. It can be seen that alignment of the tab sealant with the depression can occur whether the depression is on the top surface  52 ,  74  or the bottom surface  54 ,  76 . 
     In a further embodiment of the invention, a method for packaging roofing shingles in a bundle is disclosed. The method includes making shingles  32 ,  68  having a headlap portion  28 ,  70 , a tab portion  30 ,  72 , a granulated top surface  52 ,  74 , a bottom surface  54 ,  76 , and a tab sealant  48 ,  78 , as shown in  FIGS. 1 ,  2 A and  3 . The tab sealant  48 ,  78  is on the bottom surface  54 ,  76  of the shingles  32 ,  68 , such that the depression  56 ,  80  and tab sealant extend horizontally across the shingles when the shingles are applied to a roof (not shown). The shingles  32 ,  68  are assembled in complementary pairs back to back in a bundle, such that the depression  56 ,  80  of each shingle  32 ,  68  is aligned with the tab sealant  48 ,  78  of its complementary shingle in the bundle. 
     Although the embodiments above show depressions  56  formed by fine granules  60 , the depressions can be formed in other ways. The depressions  56 ,  80  can be provided by any suitable method, including, but not limited to tailoring the application of the asphalt coating to form depressions in the coating, or contacting the asphalt coating with a doctor blade or other device to form depressions in the coating. In one method of forming the depressions, the asphalt-coated sheet is subjected to a pressing operation as described below. 
       FIG. 4  is a schematic top view of a granule applicator  94  making two-wide shingles. The two-wide shingles have portions of fine granules  60  and headlap granules  40  deposited on the headlap portion  28  of the shingles along with prime granules  38  deposited on the tab portion  30  of the shingles. Since the fine granules  60  are of a smaller diameter than the headlap granules  40  or prime granules  38 , the depression  56  is formed. 
     In an alternate method for making the depressions, a pressing operation is used, as shown in  FIG. 5 .  FIG. 5  illustrates a cross-sectional, enlarged view of rollers  88 ,  90  shown downstream in  FIG. 1  used to create the depressions  56 ,  80  in the granulated sheet  42 . As shown in  FIGS. 1  (downstream) and  5 , the granulated sheet  42  can be passed through a pair of depression rollers  88 ,  90 , which have wheels, to form the depressions  56 ,  80  in the shingles. 
       FIG. 6  is a side cross-sectional view of a bundle  92  of laminated roofing shingles  32  stacked back to back showing the alignment of the depressions  56  with the tab sealants  48  of the complementary shingles to reduce pressure exerted on the tab sealants in the bundle. 
     In other embodiments, making shingles includes the steps of applying asphalt to a shingle mat to form an asphalt-coated sheet, applying granules of a first diameter to a portion of the asphalt-coated sheet where the depression is to be formed, and applying granules of a larger diameter to the remainder of the asphalt-coated sheet. The granules of the first diameter (i.e., fine granules) are sized within a range of from about 0.015 inch to about 0.033 inch and the granules (i.e., headlap granules and prime granules) of the larger diameter are sized within a range of from about 0.015 inch to about 0.080 inch. 
     It is further contemplated that any of the headlap portions of the laminated shingle may be thinned to accomplish reduction of asphalt in desired areas. Other means to accomplish the desired thinning of the asphalt-coated sheet include, but are not limited to removal of the top coating and the use of other suitable materials than fine granules to form the depression. 
     It is to be understood that in other embodiments, the shingles can be stacked in the bundle either face to face or back to face. Also, in another embodiment, the tab sealant can be placed on the top surface  52  of the shingle, with the depression being placed in an appropriate area to enable protection of the tab sealant from undue pressure when the shingles are stacked in the bundle. 
     The principle and mode of operation of this invention have been described in certain embodiments. However, it should be noted that this invention may be practiced otherwise than as specifically illustrated and described without departing from its scope.