BACKGROUND OF THE INVENTION

[0001 ] Roofing boards can include particle boards, gypsum boards, or foam insulation boards. Some include facers. Others do not. Polyisoinsulation boards include facers for manufacturing (foam laydown) and to provide many of the product's performance properties. The majority of facers fall into two categories: Glass

Reinforced Felt (GRF) or Coated Glass Faced (CGF). GRF facers are also known as "paper" facers given their craft paper appearance. GRF facers generally range in color from light brown to darker brown and are made from fiberglass reinforced pulp paper. CGF facers, on the other hand, tend towards white to off-white in color and are made by coating a non-woven fiberglass scrim. Insulation facers, whether GRF or CGF, are the same color on both sides of the board.

[0002] Adhering single-ply membranes to roofing boards, such as insulation boards is common practice and is becoming a more preferred method of roof installation. Each adhesive has its own requirements in terms of "setup time". In other words, the adhesive has to flash-off, get to string time, etc. before the membrane can be adhered to the insulation. The setup time can vary dramatically based on the ambient environmental conditions (e.g., air temperature, insulation/membrane temperature, humidity, sunlight/solar energy, etc.) on the rooftop.

SUMMARY OF THE INVENTION

[0003] When the ambient environmental conditions create longer than desired adhesive setup times, a darker-colored surface or facer has the ability to absorb the sun's radiant energy and help to speed up the setup times. Transferring the sun's radiant energy to the roofing board outer surface produces several outcomes, including, but not limited to, warmer facer temperature and increased drying potential, ultimately leading to reduced adhesive setup times.

[0004] When the ambient environmental conditions create shorter than desired adhesive setup times, a lighter-colored surface or facer has the ability to reflect the sun's radiant energy and help to slow them down. Reflecting the sun's radiant energy from the surface produces several outcomes, including, but not limited to cooler facertemperatures and reduced drying potential, ultimately leading to extended adhesive setup times. [0005] In an embodiment, the present invention provides a roofing board, such as a foam board insulation product, with surfaces on one side of the board and on the other side of the board having different light absorption characteristics. The sides of the board referenced are the two largest surface area sides of the six-sided board, generally described as the top and bottom. The varying light absorption characteristics of the surfaces would allow the end-user to choose the side of the board most appropriate for the ambient environmental conditions at any given time on the jobsite.

[0006] In an embodiment, the present invention provides a roofing board, such as a foam board insulation product, with a lighter surface on one side of the board and a darker surface on the other side of the board. For purposes of describing the surface color/hue differences, one side of the board would have a surface color darker than, for example, Pantone® Cool Gray 5 and the other side would have a color lighter than Pantone® Cool Gray 5. The surface differences can also be described in terms of relative reflectivity, which results in potential temperature differences based on which surface is exposed to the sun.

[0007] The objects and advantages of present will be further appreciated in light of the following detailed descriptions and drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a perspective view of an embodiment of the present invention; and [0009] FIG. 2 is a cross-sectional view broken away, showing the insulation board of FIG. 1 covered with a roofing membrane.

DETAILED DESCRIPTION OF THE INVENTION

[0010] Embodiments of the present invention provide a roofing board, such as an insulation board, particle board, gypsum board and the like, with two exposed surfaces with different colors, one lighter than the other. An embodiment of the present invention is described below with reference to a foam insulation board, but embodiments of the present invention mayinclude any roofing board.

[001 1 ] As shown in FIG. 1 , an insulation board 10 is provided, having a first outer planar surface 1 1 , a second opposed outer planar surface 12, with a foam insulation layer 1 3 separating the two. Surfaces 1 1 and 12 are facers, typically used in foam insulation boards. However, facer-less foam boards or other facer-less boards can also be used. The facers can be, for example, Glass Reinforced Felt or Coated Glass Faced. The foam insulation layer 13 can be any foam typically employed for insulation purposes and, in particular, roofing insulation purposes. The foam can be, for example, polyisocyanurate foamorextruded (XPS)or expanded (EPS) polystyrene.

However, embodiments of the present invention are not limited to the particular foam or the particular facing material.

[0012] The surfaces 1 1 and 12 of board 10 have different light absorbing characteristics. The difference in light absorbing characteristics may be expressed in a variety of characteristics including, without limitation, surface color, surface reflectivity, and surface temperature compared to ambient temperature. In one aspect, one surface, for example surface 1 1 , is lighter in color than the other surface, for example surface 12. For example, surface 1 1 may be lighter than Pantone® Cool Gray 5, whereas surface 1 2 is darker than Pantone® Cool Gray 5. In another aspect, one surface, for example surface 1 1 , has a higher solar reflectance than the other surface, for example surface 12 (e.g., as determined by ASTM E1918). For example, surface 1 1 may have a solar reflectance of 45% or greater, whereas surface 12 may have a solar reflectance of 8% or lower.The solar reflectance of the surfaces 1 1 , 12 may be varied based on, for example, the coloring agents used on surfaces 1 1 , 12. For example, coloring agents (e.g. pigments, dyes, etc.) utilized forsurface 1 2 allow the darker facer to absorb the sun's energy, while the coloring agents utilized forsurface 1 1 allow the lighter facer to reflect the sun's energy. In another aspect, when each surface is exposed to the sun, one surface, for example surface 1 1 , may be cooler than the ambient temperature while the other surface, for example surface 12, may be warmer than ambient temperature. For example, surface 1 1 may be at or below ambient temperature when exposed to the sun. The temperature of surface 1 1 may be, for example, 5°F or more below ambient temperature or between 5°F and 10°F below ambient temperature. For another example, surface 12 may be above ambient temperature when exposed to the sun. The temperature of surface 12 may be, for example, 30°F or more above ambient temperature or between 30°F and 45°F above ambient temperature. When used in a roofing system, the different light absorbing characteristics of the surfaces 1 1 and 1 2 facilitate proper installation of a roof membrane.

[0013] As shown in FIG. 2, surface 12 of board 10 is positioned on a roof deck (not shown). Board 10 can be affixed to the roof deck in a variety of different manners and is typically mechanically fastened or adhered to the roof deck. A membrane layer 14 is then adhered to, in this case, surface 1 1 of board 10 with an adhesive layer 16. The membrane layer 14 can be any membrane typically used for roofing applications.

These are typically polymeric membranes and can include, for example, EPDM, PVC, TPOelastomer, as well as many others. Typically, built-up roofs based on hot applied asphaltic material would not be utilized in the present invention. The adhesive layer 16 can be any adhesive typically used to apply the selected membrane to the board 10.

[0014] As indicated, surface 1 1 provides a lighter surface, which does not absorb as much heat as would surface 12, if exposed to the sun. Thus, when a roof is installed in the summer with hotter temperatures, exposing surface 1 1 upwardly in contact with the adhesive layer 16 will keep the temperature of the adhesive lower, allowing it to cure properly. Because the temperature of the surface 1 1 may be at or lower than it would be if it were absorbing energy from the sunlight, the time for the adhesive layer 16 to cure is increased compared to a configuration where the surface temperature issignificantly above the ambient temperature due to the sunlight. This may provide additional working or "open" time before the membrane layer 14 must be positioned on the adhesive layer 16 in the final position.When adhering membrane layer 14 to surface 1 1 compared to surface 1 2, an increase in the "tack-free" time, or the time before adhesive layer 16 becomes tacky,may be 10% or greater, 25% or greater, 40% or greater, between 1 0% and 55%, or between 25% and 55%.

[0015] Alternately, surface 12 could be the upper surface to which the membrane layer 14 is adhered. This surface 12 would be the upper layer when the ambient temperature is lower than desirable for the particular adhesive application where the cure time would be longer than desirable. When the ambient temperature is relatively cold, the time for the adhesive layer 16 to cure when membrane layer 14 is adhered to surface 12 is reduced compared to a configuration where the surface temperature of board 10 is at or below the ambient temperature. In other words, surface 12 will absorb more heat from the sun, raising the outer temperature of board 10 and, again, facilitating adhesion of the membrane layer 14 to the surface 12 with adhesive layer 16. When adhering membrane layer 14 to surface 12 compared to surface 1 1 , a reduction in the "tack-free" time, or the time before adhesive layer 16 becomes tacky, may be 10% or greater, 25% or greater, 40% or greater, between 1 0% and 55%, or between 25% and 55%.

[0016] Thus, embodiments of the present invention allow a roofing installer to choose which surface of the roofing board to expose while installing a roof, thus affecting the temperature of the adhesive and, accordingly, the cure time as the membrane layer 14 is adhered to board 1 0. The actual increase or decrease in cure time may be dependent on the ambient temperature, UV index, cloud cover, wind speed, and humidity. For example, the decrease in cure time when membrane layer 14 is adhered to surface 1 2 may be reduced due to significant cloud cover.

[0017] Roofing boards according to embodiments of the present invention may be used regardless of whether a membrane is adhered or otherwise mechanically fastened to the roofing board. For example, in an aspect of the present invention, use of the board 10 may decrease the installation time for a thermoplastic polyolefin (TPO) roofing membrane irrespective of the membrane attachment method. In that regard, a

TPOmembrane is often unrolled on a roof before being adhered or otherwise attached. TPO membranes, which are less supple than other membranes (e.g., EPDM and PVC), require time to unwind and adjust to the shape of the roof. When a TPO membrane is applied to surface 12 of board 10, the increased surface temperature may reduce the shape adjustment time of the TPO membrane. Accordingly, the overall installation time may be reduced.

[0018] While specific embodiments have been described in considerable detail to illustrate the present invention, the description is not intended to restrict or in any way limit the scope of the appended claims to such detail. The various features discussed herein may be used alone or in any combination. Additional advantages and

modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope of the general inventive concept: