ROOFING SYSTEM AND METHOD FOR PREPARING THE SAME

Abstract

A roof system comprising a roof deck, an insulation layer, a coverboard disposed over said insulation layer, where said coverboard includes a foam core and a facer including a fibrous mat and an interfacial region disposed between said core and said mat, and a layer of asphalt.

Description

This application claims the benefit of U.S. Provisional Application Ser. No. 61/864,110, filed Aug. 9, 2013, which is incorporated herein by reference.

FIELD OF THE INVENTION

Embodiments of the invention are directed toward roofing systems and methods for preparing the same wherein polyisocyanurate cover boards are employed.

BACKGROUND OF THE INVENTION

In the roofing art, particularly in the covering of flat or low-sloped roofs, built-up roofing (BUR) systems may be employed. One common technique for preparing a BUR system includes the use of a liquid asphaltic material, which is made liquid by heating the asphaltic material to at least a temperature where the asphaltic material flows. In this regard, reference may be made to hot asphalt. As is generally known in the art, one or more reinforcing fabrics may be applied to the roof surface in conjunction with one or more applications or coatings of the hot asphalt. Also, reflective materials, such as rocks, are typically applied over the asphaltic surface, which is formed by application of the hot asphalt, in order to protect the asphaltic surface from solar radiation.

While the roof surface, which may also be referred to as a roof deck, to which the asphaltic material is applied, may include robust materials such as wood or concrete, it is often the situation where one or more layers of insulation are applied to the roof deck prior to application of the hot asphalt. The insulation is often in the form of cellular insulation boards or panels, such as polyisocyanurate or polystyrene insulation boards. These insulation boards, however, do not have the thermal stability to withstand the heat associated with the hot asphalt, which could exceed temperatures of 260° C. during application.

In view of this shortcoming, it is often required to place protection over the insulation prior to application of the hot asphalt. For example, fiberglass-backed gypsum board is often applied to cover the insulation board and, among other things, protect the insulation board from the heat of the hot asphalt.

One shortcoming of the fiberglass-backed gypsum board is its weight, which can be a significant factor impacting the speed and cost of installation. While high-density polyisocyanurate boards have grown in popularity as insulation coverboards due to their light weight and installation ease, these boards have proven inferior in protecting insulation during installation of a BUR system since these polyisocyanurate cover boards are themselves suspect to damage or distortion from the heat of the hot asphalt.

SUMMARY OF THE INVENTION

One or more embodiments of the present invention provides a roof system comprising a roof deck, an insulation layer, a coverboard disposed over said insulation layer, where said coverboard includes a foam core and a facer including a fibrous mat and an interfacial region disposed between said core and said mat, and a layer of asphalt.

One or more embodiments of the present invention provides a method for installing a roof system, the method comprising applying a layer of coverboards to a layer of insulation, where the coverboards include a foam core and a facer including a fibrous mat and an interfacial region disposed between said core and said mat and applying a liquefied hot-melt sealant directly to the coverboard.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional, fragmentary view of a building structure having a roof system according to one or more embodiments of the present invention.

FIG. 2 is a fragmentary perspective view of a coverboard employed in the practice of one or more embodiments of the present invention.

FIG. 3 is a cross-sectional view of a coverboard employed in the practice of one or more embodiments of the present invention.

FIG. 4 is a cross-sectional view of a coverboard employed in the practice of one or more embodiments of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Embodiments of the invention are based, at least in part, on the discovery of a polyisocyanurate coverboard that is useful in protecting insulation board during installation of a hot sealant material (e.g. hot asphalt), such as used to create a built-up roof system. In one or more embodiments, the cover board includes a polyisocyanurate foam core having a relatively high density and a facer including a fibrous mat, wherein an interfacial region is disposed between the foam core and the mat. It has unexpectedly been discovered that the combination of the relatively high density core and the interfacial region between the mat and the foam core provides a coverboard that can withstand the thermal stresses of a hot sealant. Advantageously, these coverboards can be used with hot sealant materials to not only protect the underlying insulation layers, but the coverboards themselves are not deleteriously impacted. Accordingly, embodiments of the invention are directed toward a roof system that includes a coverboard and a layer of asphalt applied to the coverboard, as well as methods for producing the same.

Roof System

A built-up roof system according to embodiments of the invention can be described with reference to FIG. 1, which shows a building structure 10 having a roof system 13 including a roof deck 15, an insulation layer 17, a coverboards 19, and a built-up roof 21, which may also be referred to as BUR 21. While embodiments of the invention are described with respect to a built-up roof system, the invention is not limited to any specific type of built-up roof system. Instead, practice of the invention is applicable to any roofing situation wherein hot asphalt is applied. BUR 21 may include a first sealant layer 23, optional reinforcing fabric 25, optional second sealant layer 27, and optional reflective or protective material 29. Coverboards 19, as will be described in greater detail herein, include a foam core and at least one facer including a fibrous mat and an interfacial region disposed between the mat and the core. This at least one mat is disposed on at least upper planar surface 20 of coverboard 19 and is thereby adjacent to first sealant layer 23. As is known in the art, BUR 21 may include multiple reinforcing fabrics and multiple sealant layers (not shown), and it is understood that these multiple layers derive from multiple applications of liquid sealant compositions. Also, the roof system may include multiple reinforcements (not shown) deriving from multiple applications or layers of reinforcing fabric applied between the multiple applications of molten sealant material. In one or more embodiments, the respective sealant layers are monolithic.

Roof Deck

Practice of this invention is not limited by the selection of any particular roof deck. Exemplary roof decks include concrete pads, steel decks, wood beams, and foamed concrete decks.

Insulation Layer

Practice of this invention is likewise not limited by the selection of any particular insulation board. As is known in the art, several insulation materials can be employed. In one or more embodiments, the insulation is a foamed insulation board, which may be referred to as a cellular insulation board. In one or more embodiments, the cellular insulation includes polymeric struts or plates. For example, these boards may include polyurethane, polyisocyanurate, blended polyurethane/polyisocyanurate, and polystyrene cellular materials.

In one embodiment, the insulation board comprises polyurethane or polyisocyanurate cellular material. These insulation boards are known in the art as disclosed in U.S. Pat. Nos. 6,117,375, 6,044,604, 5,891,563, 5,573,092, U.S. Publication Nos. 2004/01099832003/0082365, 2003/0153656, 2003/0032351, and 2002/0013379, as well as U.S. Ser. Nos. 10/640,895, 10/925,654, and Ser. No. 10/632,343, which are incorporated herein by reference. In general, polyurethane is characterized by having an index of from about 100 to about 120; polyisocyanurate is generally characterized by having an index that is in excess of 150 (in other embodiments at least 175, and in other embodiments at least 200; and insulation with an index between 120 and 150 generally includes a mix of polyurethane and polyisocyanurate.

In those embodiments where the insulation layer comprises polyurethane or polyisocyanurate cellular material, these cellular materials may be defined by a foam density (ASTM C303) that is less than 2.5 pounds per cubic foot, in other embodiments less than 2.0 pounds per cubic foot, in other embodiments less than 1.9 pounds per cubic foot, and still in other embodiments less than 1.8 pounds per cubic foot. In one or more embodiments, these polyurethane or polyisocyanurate insulation layers may also be characterized by having a density that is greater than 1.50 pounds per cubic foot and optionally greater than 1.55 pounds per cubic foot.

CoverBoard

Configuration of Board

A coverboard according to one or more embodiments is depicted in FIG. 2. Board 30 includes a cellular body or foam core 31, which may generally have a planar shape, and includes first planar surface 32 and second planar surface 34. Foam core 31 may also be characterized by a thickness 40, a length 36, and a width 38. Length 36 and width 38 of board 30 may vary, and these embodiments are not necessarily limited by the selection of a particular length or width. Nonetheless, because these boards are advantageously employed in the construction industry, board 10 may be sized to a 4′×8′ sheet (e.g., 3.75′×7.75′), a 4′×10′ sheet, or a 4′×4′ sheet. The thickness 40 of the foam core can generally be greater than about 0.25 inches, and may be from about 0.5 to 6.0 inches or in other embodiments from about 1.0 to 4.0 inches in thickness.

Board 30 includes a first facer 42, which can be positioned adjacent one of the first or second planar surfaces 32 or 34. For example, as shown in FIG. 2, facer 42 may be positioned adjacent second planer surface 32. In one or more embodiments, facer 42 can be integral with planar surface to which it is adjacent as a result of the methods employed to manufacture board 30, which will be disclosed below.

As also shown in FIG. 2, board 30 may also include a second optional facer 43 positioned adjacent the planer surface opposite the planar surface on which facer 42 is positioned. For example, facer 42 is positioned adjacent second planer surface 32, and facer 43 is positioned adjacent first planer surface 34. Facer 43 can include the same or different materials or compositions, as well as the same or different thickness as facer 42.

As shown in FIG. 3, at least one of the facers (e.g. facer 42 and/or facer 43) includes a mat 46 and a coating layer 48. Mat 46 may also be referred to as fabric 46. Coating layer 48 may also be referred to as interfacial region 48, and comprises coating material. The coating material may also be dispersed in interstices that exist within mat 46, and this coating material may generally be referred to as penetrated coating material 50. As shown in FIG. 4, at least one of the facers (e.g. facer 42 and/or facer 43) includes first coating layer 60 and second coating layer 62, as well as mat 46 and penetrated coating material 66.

Mat

As described above, one or more of the facers employed in practicing this invention (e.g. facer 42 and/or facer 43) includes a mat (e.g. mat 46). In one or more embodiments, the mat is a non-woven inorganic mat. Exemplary types of non-woven mat include fiberglass mats, which may also be referred to as glass mats. In one or more embodiments, the non-woven fiberglass mats include include glass fibers and a binder which binds the glass fibers together and maintains the fibers in a mat form. Any type of glass fiber mat can be used in the composite board. For example, a non-woven glass fiber mat can be made with glass fibers and bonded with an aqueous thermosetting resin such as, for example, urea formaldehyde or phenolic resole resins.

In one or more embodiments, the dimensional and weight characteristics of the glass fiber mat are not particularly limited, and can depend on the specific application and desired properties of the coverboard. For example, the basis weight of the glass fiber mat 46 can be from about 50 grams per square meter to about 150 grams per square meter. The thickness of the glass fiber mat 46 can be, for example, from about 0.015 inch to about 0.05 inch. The basis weight and thickness characteristics can be adjusted depending upon the desired rigidity, strength and weight of the composite board.

The thickness of the facer material may vary; for example, it may be from about 0.01 to about 1.00 or in other embodiments from about 0.015 to about 0.050 inches thick.

Coating Material

As described above, one or more of the facers employed in practicing this invention (e.g. facer 42 and/or facer 43) includes one or more coating layers (e.g. coating layer 60 or 62), as well as coating material disposed within the interstices of the mat, which coating material is referred to as penetrated coating material 66.

In one or more embodiments, the coating layers, as well as the coating material, include a binder and an inorganic filler. The binder bonds the inorganic filler together and additionally bonds the inorganic filler to the glass fiber mat. The binder can be polymeric and derive from, for example, a latex binder, a starch or combinations thereof. Examples of latex binders include butyl rubber latex, styrene butadiene rubber (SBR) latex, neoprene latex, acrylic latex and SBS latex, and can in particular include the SBR latex. In one embodiment, each of the first and second binding compositions can include from about 1% latex to about 15% latex, based on the respective weight of each binding composition. In another embodiment, each of the first and second binding compositions can include from about 1% latex to about 5% latex, based on the respective weight of each binding composition. Examples of a suitable inorganic filler include calcium carbonate, clay, talc, mica, perlite, hollow ceramic spheres or a combination thereof. In an exemplary embodiment, the inorganic filler can include calcium carbonate. In an exemplary embodiment, the inorganic filler can be present in the first and second binding compositions in an amount from about 80% to about 98%, based on the respective weight of each composition.

In one or more embodiments, the coating layers (e.g. layers 60 and 62), as well as the penetrated coating material, allow for a relatively high degree of air permeability of the facer. In one or more embodiments, the coating layers are discontinuous or irregular (e.g. have an irregular thickness), and the penetrated coating may not fill all of the interstices of the mat, either of which may contribute to the relatively high degree of air permeability of the facer.

In one or more embodiments, coating layers (e.g. layers 60 and 62), as well as penetrated coating material (e.g. 66), derives from employing a double-coated glass mat, which is a glass mat that includes coating material applied to both planar surfaces of the glass mat.

In one or more embodiments, the double-coated facer is characterized by an air permeability, which may also be referred to as porosity, as determined by ARC-WT-006 (which correlates to TAPPI T460om-96), of less than 300, in other embodiments less than 250, in other embodiments less than 200, in other embodiments less than 150, in other embodiments less than 100, in other embodiments less than 70, in other embodiments less than 50, in other embodiments less than 40, and in other embodiments less than 30 Gurley seconds/300 cubic centimeters.

In one or more embodiments, the double-coated facer is characterized by a coating weight of greater than 500, in other embodiments greater than 600, in other embodiments greater than 700, in other embodiments greater than 800, in other embodiments greater than 810, in other embodiments greater than 820, in other embodiments greater than 830, in other embodiments greater than 840, in other embodiments greater then 850, in other embodiments greater then 860, in other embodiments greater 870, in other embodiments greater 880, in other embodiments greater than 890, and in other embodiments greater than 900 grams per square meter. In one or more embodiments, the coating weight is less than 1000, in other embodiments less than 950, and in other embodiments less than 920 grams per square meter. As used herein, the term “coating weight” means the weight of the coating per area of the at least one glass fiber mat, which includes both coating layers as well as the penetrated coating material.

Foam Core

In one or more embodiments, body 31 includes a polyurethane or polyisocyanurate cellular structure, which refers to an interconnected network of solid struts or plates that form the edges and faces of cells. These cellular structures may, in one or more embodiments, also be defined by a “relative density” that is less than about 0.8, in other embodiments less than 0.5, and in other embodiments less than 0.3. As those skilled in the art will appreciate, “relative density” refers to the density of the cellular material divided by that of the solid from which the cell walls are made. As the relative density increases, the cell walls thicken and the pore space shrinks such that at some point there is a transition from a cellular structure to one that is better defined as a solid containing isolated porosity.

Despite the cellular nature of body 31, it has a relatively high density. In one or more embodiments, the density of body 31 is greater than 2.5 pounds per cubic foot (12.2 kg/m²), as determined according to ASTM C303, in other embodiments the density is greater than 2.8 pounds per cubic foot (13.7 kg/m²), in other embodiments greater than 3.0 pounds per cubic foot (14.6 kg/m²), and still in other embodiments greater than 3.5 pounds per cubic foot (17.1 kg/m²); on the other hand, in one or more embodiments, the density of body 31 may be less than 20 pounds per cubic foot (97.6 kg/m²), in other embodiments less than 10 pounds per cubic foot (48.8 kg/m²), in other embodiments less than 6 pounds per cubic foot (29.3 kg/m²), in other embodiments less than 5.7 pounds per cubic foot (28.8 kg/m²), in other embodiments less than 5.5 pounds per cubic foot (28.3 kg/m²), in other embodiments less than 5.2 pounds per cubic foot (27.8 kg/m²), in other embodiments less than 5.0 pounds per cubic foot (27.3 kg/m²), and still in other embodiments less than 4.7 pounds per cubic foot (26.9 kg/m²).

In one or more embodiments, body 31 is characterized by an ISO Index, as determined by PIR/PUR ratio as determined by IR spectroscopy using standard foams of known index (note that ratio of 3 PIR/PUR provides an ISO Index of 300), of at least 270, in other embodiments at least 285, in other embodiments at least 300, in other embodiments at least 315, and in other embodiments at least 325. In these or other embodiments, the ISO Index is less than 360, in other embodiments less than 350, in other embodiments less than 340, and in other embodiments less than 335.

BUR System

BUR Sealant Material

As indicated above, the BUR system includes a sealant layer that derives from a liquid sealant material; these systems may also be referred to as hot-mop systems. In one or more embodiments, the resultant sealant layer is a monolithic layer over the area to which it is applied. In one or more embodiments, the sealant material is capable of creating a moisture resistant barrier that will meet the standards of ASTM E 108.

In one or more embodiments, the liquid sealant is a hot melt sealant, which includes those materials that can be liquefied at elevated, yet commercially practical, temperatures. In one or more embodiments, the liquid sealants can be liquefied at temperature of at least 135° C., in other embodiments at least 155° C., and in other embodiments at least 195° C. In one or more embodiments, the liquid sealants include those materials that can be liquefied at temperatures between 140° C. and 260° C. In one or more embodiments, the hot melt liquid sealant materials solidify, at least to the extent that they can no longer be poured and/or flow, at temperatures below 135° C., in other embodiments below 120° C., and in other embodiments below 110° C. In one or more embodiments, the liquid sealants are characterized, in their liquefied state (i.e. above the temperatures set forth above), by being pourable, flowable, and/or spreadable.

Practice of one or more embodiments of the present invention is not limited by the selection of any particular hot melt sealant. In one or more embodiments, the hot melt sealant is pitch, tar, asphalt, and combinations thereof.

As the skilled person readily understands, pitch includes carbonaceous residue left from the distillation of substances such as coal tar, pine tar, rosin, petroleum and fatty acids, or include naturally occurring substance having properties similar to the forgoing distillate residues.

The skilled person also understands that tar includes the residue left from the destructive distillation of carbon rich materials such as coal, wood, and petroleum or as a naturally occurring substance having properties similar to the destructive distillation residues recited.

Further, the skilled person understands that asphalt includes a thick viscous mixture of hydrocarbons (bitumen) obtained chiefly as the residue of petroleum distillation or as naturally occurring materials. The asphalt material may be derived from any asphalt source, such as natural asphalt, rock asphalt, produced from tar sands, or petroleum asphalt obtained in the process of refining petroleum. In one or more embodiments, the asphalt material may meet specific grade definitions. In other embodiments, asphalt binders may include a blend of various asphalts not meeting any specific grade definition. This includes air-blown asphalt, vacuum-distilled asphalt, steam-distilled asphalt, cutback asphalt or roofing asphalt. Alternatively, gilsonite, natural or synthetic, used alone or mixed with petroleum asphalt, may be selected. Synthetic asphalt mixtures suitable for use in the present invention are described, for example, in U.S. Pat. No. 4,437,896. In one or more embodiments, asphalts may include asphaltenes, resins, cyclics, and saturates. The percentage of these constituents in the overall asphalt binder composition may vary based on the source of the asphalt. Asphaltenes include black amorphous solids containing, in addition to carbon and hydrogen, some nitrogen, sulfur, and oxygen. Trace elements such as nickel and vanadium may also be present. Asphaltenes are generally considered as highly polar aromatic materials of a number average molecular weight of about 2000 to about 5000 g/mol, and may constitute about 5 to about 25% of the weight of asphalt. Resins (polar aromatics) include dark-colored, solid and semi-solid, very adhesive fractions of relatively high molecular weight present in the maltenes. They may include the dispersing agents of peptizers for the asphaltenes, and the proportion of resins to asphaltenes governs, to a degree, the sol- or gel-type character of asphalts. Resins separated from bitumens may have a number average molecular weight of about 0.8 to about 2 kg/mol but there is a wide molecular distribution. This component may constitute about 15 to about 25% of the weight of asphalts. Cyclics (naphthene aromatics) include the compounds of lowest molecular weight in bitumens and represent the major portion of the dispersion medium for the peptized asphaltenes. They may constitute about 45 to about 60% by weight of the total asphalt binder, and may be dark viscous liquids. They may include compounds with aromatic and naphthenic aromatic nuclei with side chain constituents and may have molecular weights of 0.5 to about 9 kg/mol. Saturates include predominantly the straight- and branched-chain aliphatic hydrocarbons present in bitumens, together with alkyl naphthenes and some alkyl aromatics. The average molecular weight range may be approximately similar to that of the cyclics, and the components may include the waxy and non-waxy saturates. This fraction may from about 5 to about 20% of the weight of asphalts. In these or other embodiments, asphalt binders may include bitumens that occur in nature or may be obtained in petroleum processing. Asphalts may contain very high molecular weight hydrocarbons called asphaltenes, which may be soluble in carbon disulfide, pyridine, aromatic hydrocarbons, chlorinated hydrocarbons, and THF. Asphalts or bituminous materials may be solids, semi-solids or liquids.

In one or more embodiments, the asphalt includes AC-5, AC-10 and AC-15. These asphalts typically contain about 40 to about 52 parts by weight of aromatic hydrocarbons, about 20 to about 44 parts by weight of a polar organic compound, about 10 to about 15 parts by weight of asphaltene, about 6 to about 8 parts by weight of saturates, and about 4 to about 5 parts by weight of sulfur. Nevertheless, practice of the present invention is not limited by selection of any particular asphalt.

In one or more embodiments, the molecular weight of the aromatic hydrocarbons present in asphalt may range between about 300 and 2000, while the polar organic compounds, which generally include hydroxylated, carboxylated and heterocyclic compounds, may have a weight average molecular weight of about 500 to 50,000. Asphaltenes, which are generally known as heavy hydrocarbons, are typically of a high molecular weight and are heptane insoluble. Saturates generally include paraffinic and cycloaliphatic hydrocarbons having about 300 to 2000 molecular weight.

In one or more embodiments, bitumens may be used. Bitumens are naturally occurring solidified hydrocarbons, typically collected as a residue of petroleum distillation. Gilsonite is believed to be the purest naturally formed bitumen, typically having a molecular weight of about 3,000 with about 3 parts by weight complexed nitrogen.

For purposes of this specification, these materials (i.e. the pitch, tar, asphalts) may be referred to collectively as asphalt or bitumen. Also, given the popularity of asphalt materials in these uses, reference may be made to asphalt or bitumen, with the understanding that hot melt sealants may likewise employed unless otherwise stated. Reference may also be made to hot or molten asphalt with the understanding that these terms refer to sealants generally, or asphalt specifically, above their threshold temperatures at which they are pourable, flowable, and/or spreadable.

In one or more embodiments, the liquid sealant material is an asphaltic hot melt sealant that includes additional constituents as known in the art. For example, in one or more embodiments, the sealant includes a polymeric modifier, and therefore reference may be made to modified-bitumen compositions. For example, the modified-bitumen compositions may include polymeric modifiers such as styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), as well as hydrogenated verwsion thereof (e.g., SEPS and SEBS), atactic polypropylene polymers, and ethylene/styrene copolymers or “interpolymers.”

Additionally, the asphaltic hot melt sealants useful in practice of this invention may also optionally include typical additives such as fire retardants, flame retardants, antioxidants, colorants, stabilizers, fillers, and mixtures thereof. In one or more embodiments, the asphalt composition meets the standards of ASTM D6152 or ASTM D 312.

BUR Protective Material

As explained above, the BUR may include a protective material over one or more of the sealant layers. This protective material may include weather-resistant particles. In one or more embodiments, these particles serve not only a cosmetic purpose but also increase the weather resistance of the hot melt sealant layer (i.e. the flood layer) of the BUR. In one or more embodiments, the weather resistant particles include washed gravel (pebbles) or chipped marble.

BUR Fabric Reinforcement

In one or more embodiments, the fabric reinforcement may include a textile fabric, which may include woven and/or non-woven fabrics. Various fabric reinforcements are known in the art, and practice of the present invention is not necessarily limited by the selection of a particular fabric. In one or more embodiments, the reinforcement may be fabricated from fiberglass and/or synthetic yards or filaments. Exemplary synthetic yarns include those prepared from polyesters or polyimides. In one or more embodiments, the fabrics meet the standards of ASTM D2178.

Manufacture of Boards

Laminator

The coverboards employed in embodiments of this invention can be manufactured by using known techniques. In one or more embodiments, the coverboards are made within a laminator construction line where foam is deposited onto a continuously moving web of the facer described herein. Consistent with the teachings of this invention, the foam material is deposited onto a planar surface of the facer and contacts the coating layer. It is believed that a technologically useful bond is created between the foaming material and the coating material that forms the coating layer and/or the penetrated coating. As the foam begins to rise, a second facer, which may also conform to the facers of this invention, is positioned above the foam and the composite is run through the laminator. In positioning the top facer, the coating on the planar surface of the second facer is also contacted to the foam.

Manufacture of Glass Mat

The glass fiber mat can be formed from any suitable process. For example, these glass fiber mats can be formed from an aqueous dispersion of glass fibers. In such process, a resin binder can be applied to a wet non-woven web of fibers and after removing excess binder and water, the web can be dried and heated to cure the resin binder to form the non-woven mat product. Non-woven glass fiber mats can also be made by chopping dry strands of glass fibers bound together with a binder to form chopped strand, collecting the chopped strand on a moving conveyor in a random pattern, and bonding the chopped strand together at their crossings by dusting a dry, powdered thermoplastic binder like a polyamide, polyester, or ethylene vinyl acetate on wetted chopped strands followed by drying and curing the binder.

Application of Coating to Glass Mat

In one or more embodiments, a coating composition is applied to each of the planar surfaces of the glass mat. In other words, a first binding composition may be applied to a first planar surface (which may be referred to as an upper surface), and a second binding composition may be applied to a second planar surface (which may be referred to as a lower surface) opposite the first planar surface. The first and second binding compositions may be the same. Any method suitable for applying a binding composition or coating to a glass fiber mat or impregnating a glass fiber mat with a binding composition or coating may be used to apply the first binding composition to the upper surface of the at least one glass fiber mat and the second binding composition to the lower surface of the at least one glass fiber mat. The first and second binding composition can be applied by air spraying, dip coating, knife coating, roll coating, or film application such as lamination/heat pressing. The ability to produce coated facers is known as described in U.S. Pat. Nos. 5,102,728, 5,112,678, and 7,138,346, which are incorporated herein by reference.

Manufacture of Foam Core

In general, and in a manner that is conventional in the art, the boards of the present invention may be produced by developing or forming a polyurethane and/or polyisocyanurate foam in the presence of a blowing agent. The foam may be prepared by contacting an A-side stream of reagents with a B-side stream of reagents and depositing the mixture or developing foam onto a facer positioned on a laminator. As is conventional in the art, the A-side stream includes an isocyanate and the B-side includes an isocyanate-reactive compound.

According to one or more aspects of this invention, the facer, which as described above includes a coating layer on at least one planar surface of a fibrous mat, is positioned on the laminator so that the developing foam is applied to the coating layer. As a result of this manufacturing technique, the interfacial region is created between the fibrous mat and the foam core.

In one or more embodiments, processes for the manufacture of polyurethane or polyisocyanurate coverboards, including those having a relatively high density, are known in the art as described in U.S. Pat. Nos. 8,453,390 7,972,688, 7,387,753, 7,612,120, 6,774,071, 6,372,811, 6,117,375, 6,044,604, 5,891,563, 5,573,092, and U.S. Publication Nos. 2004/0102537, 2004/0109983, 2003/0082365, and 2003/0153656, which are incorporated herein by reference.

The A-side stream typically only contains the isocyanate, but, in addition to isocyanate components, the A-side stream may contain flame-retardants, surfactants, blowing agents and other non-isocyanate-reactive components.

Suitable isocyanates are generally known in the art. Useful isocyanates include aromatic polyisocyanates such as diphenyl methane, diisocyanate in the form of its 2,4′-, 2,2′-, and 4,4′-isomers and mixtures thereof, the mixtures of diphenyl methane diisocyanates (MDI) and oligomers thereof known in the art as “crude” or polymeric MDI having an isocyanate functionality of greater than 2, toluene diisocyanate in the form of its 2,4′ and 2,6′-isomers and mixtures thereof, 1,5-naphthalene diisocyanate, and 1,4′ diisocyanatobenzene. Exemplary isocyanate components include polymeric Rubinate 1850 (Huntsmen Polyurethanes), polymeric Lupranate M70R (BASF), and polymeric Mondur 489N (Bayer).

The B-side stream, which contains isocyanate reactive compounds, may also include flame retardants, catalysts, emulsifiers/solubilizers, surfactants, blowing agents, fillers, fungicides, anti-static substances, water and other ingredients that are conventional in the art.

An exemplary isocyanate-reactive component is a polyol. The terms polyol or polyol component include diols, polyols, and glycols, which may contain water as generally known in the art. Primary and secondary amines are suitable, as are polyether polyols and polyester polyols. Useful polyester polyols include phthalic anhydride based PS-2352 (Stepen), phthalic anhydride based polyol PS-2412 (Stepen), teraphthalic based polyol 3522 (Kosa), and a blended polyol TR 564 (Oxid). Useful polyether polyols include those based on sucrose, glycerin, and toluene diamine. Examples of glycols include diethylene glycol, dipropylene glycol, and ethylene glycol. Suitable primary and secondary amines include, without limitation, ethylene diamine, and diethanolamine. In one embodiment a polyester polyol is employed. In one or more embodiments, the present invention may be practiced in the appreciable absence of any polyether polyol. In certain embodiments, the ingredients are devoid of polyether polyols.

Catalysts are believed to initiate the polymerization reaction between the isocyanate and the polyol, as well as a trimerization reaction between free isocyanate groups when polyisocyanurate foam is desired. While some catalysts expedite both reactions, two or more catalysts may be employed to achieve both reactions. Useful catalysts include salts of alkali metals and carboxylic acids or phenols, such as, for example potassium octoate; mononuclear or polynuclear Mannich bases of condensable phenols, oxo-compounds, and secondary amines, which are optionally substituted with alkyl groups, aryl groups, or aralkyl groups; tertiary amines, such as pentamethyldiethylene triamine (PMDETA), 2,4,6-tris[(dimethylamino)methyl]phenol, triethyl amine, tributyl amine, N-methyl morpholine, and N-ethyl morpholine; basic nitrogen compounds, such as tetra alkyl ammonium hydroxides, alkali metal hydroxides, alkali metal phenolates, and alkali metal acholates; and organic metal compounds, such as tin(II)-salts of carboxylic acids, tin(IV)-compounds, and organo lead compounds, such as lead naphthenate and lead octoate.

Surfactants, emulsifiers, and/or solubilizers may also be employed in the production of polyurethane and polyisocyanurate foams in order to increase the compatibility of the blowing agents with the isocyanate and polyol components.

Surfactants may serve two purposes. First, they may help to emulsify/solubilize all the components so that they react completely. Second, they may promote cell nucleation and cell stabilization. Exemplary surfactants include silicone co-polymers or organic polymers bonded to a silicone polymer. Although surfactants can serve both functions, a more cost effective method to ensure emulsification/solubilization may be to use enough emulsifiers/solubilizers to maintain emulsification/solubilization and a minimal amount of the surfactant to obtain good cell nucleation and cell stabilization. Examples of surfactants include Pelron surfactant 9920, Goldschmidt surfactant B8522, and GE 6912. U.S. Pat. Nos. 5,686,499 and 5,837,742 are incorporated herein by reference to show various useful surfactants.

Suitable emulsifiers/solubilizers include DABCO Kitane 20AS (Air Products), and Tergitol NP-9 (nonylphenol+9 moles ethylene oxide).

Flame Retardants may be used in the production of polyurethane and polyisocyanurate foams, especially when the foams contain flammable blowing agents such as pentane isomers. Useful flame retardants include tri(monochloropropyl) phosphate, tri-2-chloroethyl phosphate, phosphonic acid, methyl ester, dimethyl ester, and diethyl ester. U.S. Pat. No. 5,182,309 is incorporated herein by reference to show useful blowing agents.

Useful blowing agents include isopentane, n-pentane, cyclopentane, alkanes, (cyclo) alkanes, hydrofluorocarbons, hydrochlorofluorocarbons, fluorocarbons, fluorinated ethers, alkenes, alkynes, carbon dioxide, and noble gases. Depending on the required density of the board, the amount of blowing agent may need to be decreased up to about 95% from a standard formulation. The amount of water may also, optimally, be reduced. The less blowing agent used, the less catalyst is generally used.

Installation of Roof System

In one or more embodiments, the roofing systems of the present invention may be installed using standard techniques with the exception that the coverboards defined herein may be used as a protective barrier for an underlying insulation layer.

For example, insulation board may be applied to an existing roof system or roof deck using conventional techniques. These techniques may include mechanically fastening the insulation boards to the existing roof or roof deck, or these techniques may include the use of an adhesive to bond the insulation boards to the roof or roof deck.

In one or more embodiments, the coverboards defined herein are then installed over the insulation board layer. The coverboards may be secured to the insulation board exclusively, which can occur through the use of an adhesive material to bond the coverboard directly to the insulation layer (i.e. boards). Alternatively or in addition, the coverboards can be mechanically fastened to the roof system, which may include the use of mechanical fastening devices that penetrate not only the insulation layer but also the roof deck itself. As is known in the art, the coverboards may be arranged in a staggered pattern over the insulation boards.

In one or more embodiments, the coverboards are installed so that the facer having an interfacial region disposed between the facer and core of coverboard is exposed for application of the hot sealant material directly thereto. In other words, and according to one or more embodiments of the invention, the planar surface of the coverboard having disposed thereon (which may also be referred to as secured thereto) a coated facer wherein the coating includes a layer disposed between the mat and the core of the board, is positioned upward and away from the insulation layer. In one or more embodiments, the coverboard includes facers on opposing planar surfaces of the board and both facers have an interfacial region disposed between the facers and the core of the board. In this latter situation, either side of the coverboard may be exposed to the hot sealant to be applied and/or laid adjacent to the insulation layer.

After application of the coverboards, which creates a layer of coverboards, which may also be referred to as a protective layer, over the insulation boards or layer, a liquid sealant (e.g. hot melt asphaltic material) is applied over the coverboards. In one or more embodiments, the hot melt sealant may be applied in a spreadable state directly to (i.e. over) the coverboards by pouring, spraying, brushing, rolling, squeegeeing, sponging, swabbing, and/or mopping. In one or more embodiments, as indicated above with respect to the temperatures provided for the liquefied state of the hot melt material, the application of a hot melt sealant takes place above the threshold liquefied temperature; e.g. application takes place in the temperature range of about 135+C. to about 260° C.

An accepted procedure for creating a BUR system includes applying a liquid layer of hot melt material and then applying a layer of reinforcing material. This procedure may be alternately followed to achieve a plurality of plies of the bitumen/reinforcing material. For example, 3 or 4 plies may be applied. A final bitumen layer (flood coat) can then be applied over the plurality of plies. In one or more embodiments, the reinforcing material is applied to the previously deposited hot melt layer prior to complete solidification of the hot melt material.

After application of the flood coat, the protective material may be applied. For example, pea gravel can be applied over the flood layer. In one or more embodiments, the protective material is applied before the final hot melt sealant layer is completely solidified.

Advantages of Present Invention

As noted previously, the direct application of the hot melt sealant to the roof underlying roof system is advantageously achieved without deleterious impact on the insulation layer and the coverboard layer. For example, hot melt sealant, which may be at a temperature in of at least 200° C. or at least 230° C., or at least 260° C. can applied directly to the coverboards without deleteriously impacting the coverboard. For example, the boards are substantially free of delamination or blistering during installation or subsequent aging. Also, the boards are substantially free of deleterious bowing.

In order to demonstrate the practice of the present invention, the following examples have been prepared and tested. The examples should not, however, be viewed as limiting the scope of the invention. The claims will serve to define the invention.

EXAMPLES

Sample test roofing systems were prepared by employing the following method. The samples were tested on test roof systems that included a wood deck supported above the ground by a stand. Various polyisocyanurate foamed construction boards were installed over the wood deck and then an asphalt coating was applied over the construction board. The condition of the asphalt coating and/or sample roof was observed after application. Table I below details the type of construction board employed as well as the observations made.

The construction boards included the following. As detailed in Table I, the boards included a “high density” foam core wherein the density of the foam core was about 5 pounds per cubic foot or a “low density” foam core wherein the density of the foam core was about 1.6 pounds per cubic foot. The thickness of the foam layer is also detailed in Table I. Also, as detailed in Table I, three types of facers were disposed on the high density or low density boards. The first was a glass-reinforced paper facer of the type used on conventional polyisocyanurate board. For purposes of the Table, these facers have been designated as “paper.” The second was a standard glass facer of the type used on conventional polyisocyanurate insulation or cover boards. While facers of this nature often include a coating, the coating does not form an interfacial region between the mat and foam as contemplated by the present invention. For purposes of the Table, these facers have been designated as “glass.” The third was a coated glass facer of the type described in the present invention wherein an interfacial region exists between the mat and the foam. For purposes of the Table, these facers have been designated as “coated glass.”

The coverboards were all the hot mopped into place using Type IV asphalt. The Type IV asphalt was generally maintained at a temperature above about 475° F. during application. The hot asphalt was first applied as a ply coat followed by application of a top coat.

After about an hour following application of the hot asphalt, observations were made. Facer delamination and the formation of bubbles were recorded as set forth in Table I. The amount of bubbles were given a subjective rating on a 1 to 10 scale, a 1 signifying the greatest amount of bubble forming on the surface and 10 signifying the least amount of bubbles forming on the surface. Five different people assessed the amount of bubbles formed and the average of those five rankings is set forth in the Table.

TABLE
		Core		Perforation	Type of	Facer	Average Bubble
Sample	Facer	Density	Thickness	Y/N	Treatment	Delamination	Rating
1	Paper	1.6	0.5	Yes	None	No	5.0
2	Glass	1.6	0.5	Yes	None	No	3.3
3	Paper	1.6	0.5	No	None	Yes	4.8
4	Glass	1.6	0.5	No	None	Yes	2.3
5	Paper	5	0.5	Yes	None	No	4.5
6	Glass	5	0.5	Yes	None	No	2.3
7	Coated	5	0.5	Yes	None	No	3.5
	Glass
8	Paper	5	0.5	No	None	No	4.0
9	Glass	5	0.5	No	None	No	1.5
10	Coated	5	0.5	No	None	No	7.8
	Glass
11	Paper	1.6	1	Yes	None	Yes	4.3
12	Glass	1.6	1	Yes	None	No	3.0
13	Coated	1.6	1	Yes	None	No	3.8
	Glass
14	Paper	1.6	1	No	None	Yes	4.0
15	Glass	1.6	1	No	None	Yes	2.3
16	Coated	1.6	1	No	None	yes	7.0
	Glass
17	Paper	5	1	Yes	None	No	7.0
18	Glass	5	1	Yes	None	No	3.5
19	Coated	5	1	yes	None	No	7.5
	Glass
20	Paper	5	1	No	None	Yes	8.5
21	Glass	5	1	No	None	No	3.5
22	Coated	5	1	No	None	No	7.3
	Glass

Various modifications and alterations that do not depart from the scope and spirit of this invention will become apparent to those skilled in the art. This invention is not to be duly limited to the illustrative embodiments set forth herein.

Claims

1. A roof system comprising:

(i) a roof deck;

(ii) an insulation layer;

(iii) a coverboard disposed over said insulation layer, where said coverboard includes a foam core and a facer including a fibrous mat and an interfacial region disposed between said core and said mat; and

(iv) a layer of asphalt.

2. The roof system of claim 1, where said insulation layer includes foamed polyurethane, polyisocyanurate, polystyrene, or a mixture of two or more thereof.

3. The roof system of claim 1, where said foam core includes polyisocyanurate foam.

4. The roof system of claim 1, where said foam core of said coverboard includes polyisocyanurate foam having a density, as defined by ASTM C303, of greater than 2.5 pounds per cubic foot.

5. The roof system of claim 1, where said foam core of said coverboard includes polyisocyanurate foam having a density, as defined by ASTM C303, of greater than 3.5 pounds per cubic foot.

6. The roof system of claim 1, where said foam core of said coverboard includes polyisocyanurate foam having a density, as defined by ASTM C303, of less than 5.5 pounds per cubic foot.

7. The roof system of claim 1, where the layer of asphalt is applied to said coverboard as a hot melt.

8. The roof system of claim 1, where said interfacial region is a polymeric interfacial region.

9. The roof system of claim 1, where said mat is a glass mat.

10. The roof system of claim 1, where the build-up roof system includes at least one layer of sealant material.

11. A method for installing a roof system, the method comprising:

(i) applying a layer of coverboards to a layer of insulation, where the coverboards include a foam core and a facer including a fibrous mat and an interfacial region disposed between said core and said mat; and

(ii) applying a liquefied hot-melt sealant directly to the coverboard.

12. The roof system of claim 11, where said insulation layer includes foamed polyurethane, polyisocyanurate, polystyrene, or a mixture of two or more thereof.

13. The roof system of claim 11, where said foam core includes polyisocyanurate foam.

14. The roof system of claim 11, where said foam core of said coverboard includes polyisocyanurate foam having a density, as defined by ASTM C303, of greater than 2.5 pounds per cubic foot.

15. The roof system of claim 11, where said foam core of said coverboard includes polyisocyanurate foam having a density, as defined by ASTM C303, of greater than 3.5 pounds per cubic foot.

16. The roof system of claim 11, where said foam core of said coverboard includes polyisocyanurate foam having a density, as defined by ASTM C303, of less than 5.5 pounds per cubic foot.

17. The roof system of claim 11, where said step of applying a liquefied hot-melt sealant includes applying hot asphalt.

18. The roof system of claim 11, where said interfacial region is a polymeric interfacial region.

19. The roof system of claim 11, where said mat is a glass mat.

20. The roof system of claim 11, where the roof system includes at least one layer of sealant material.