Abstract:
A method for affixing covering products to building structures is described. The covering product includes a thermoplastic membrane, a layer in which a fabric that includes an adhesive coating, and a release liner. The layer is affixed to a primary surface of the membrane. After the covering product is transported to the building structure, the release liner is removed, and the covering produce is adhered to the building structure.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a divisional application of U.S. patent Ser. No. 10/775,207, filed 11 Feb. 2004, now abandoned, which claims the benefit of U.S. provisional appl. Nos. 60/446,277 and 60/446,283 both filed 11 Feb. 2003; the entire disclosures of these priority applications are incorporated herein by reference. 
    
    
     BACKGROUND INFORMATION 
     The present invention relates generally to covering membranes for building structures. 
     Roofing membranes, are currently applied to roof decks by gluing the membrane to the substrate to be used as an insulation layer or underlayment of a roofing deck using either a water-based adhesive or an solvent-based adhesive that is applied to a roofing membrane at the site of the roofing installation. However, current methods of applying water-based adhesives or solvent-based adhesives “on-site” result in several problems. For example, the application of a roofing membrane with a water-based adhesive is time consuming and may only be applied in limited climatic conditions. A solvent-based adhesive requires care in determining the state of the adhesive to avoid over drying and attempting to adhere the roofing membrane while the adhesive is still wet. Also, solvent-based adhesives have volatile organic component (VOC) problems and may be very flammable, causing safety issues. 
     In addition, using a thermoplastic material for roofing membranes may require an expensive adhesive. 
     To join two roofing membranes that have been adhered to a roof substrate, usually hot air is used to weld seams where the two membranes overlap. The seam welds are usually formed using hot air welders that typically cost several thousands of dollars, making the installation of conventional roofing systems quite expensive, even for professional installers. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes the shortcomings of prior methods by providing covering membranes, such as roofing membranes, that may employ a relatively inexpensive adhesive to bond the roofing membrane to a building structure such as a roof substrate. In a preferred embodiment, the present invention provides a covering membrane that may be installed easily and quickly by a non-professional without special tools. 
     According to a first broad aspect of the present invention, there is provided a covering product comprising: a membrane comprising a thermoplastic; a fabric layer attached to a lower side of the membrane, the fabric layer being comprised of a fabric material; and an adhesive covering at least a portion of a lower side of the fabric layer for allowing the covering product to be adhered to a building structure. 
     According to second broad aspect of the invention, there is provided a method for mounting at least one membrane on a building structure comprising the following steps: (a) providing building structure; and (b) adhering a first membrane on the building structure by using a first adhesive coated on a first fabric layer bonded to the first membrane, the first fabric layer being comprised of a first fabric material. 
     Other features of the present invention will be apparent from the following detailed description of the preferred embodiment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a cross-sectional view of a covering product constructed in accordance with a preferred embodiment of the present invention; 
         FIG. 2  is a cross-sectional view illustrating two roofing membranes mounted on a roof substrate; 
         FIG. 3  is a cross-sectional view of a covering product constructed in accordance with a preferred embodiment of the present invention; 
         FIG. 4  is a cross-sectional view illustrating two roofing membranes mounted on a roof substrate; 
         FIG. 5  is a cross-sectional view of a covering product constructed in accordance with a preferred embodiment of the present invention; and 
         FIG. 6  is a cross-section view of a covering product of the present invention mounted on the upper surface of a tunnel. 
     
    
    
     DETAILED DESCRIPTION 
     The following definitions are used throughout this application. 
     Where the definition of terms departs from the commonly used meaning of the term, applicant intends to utilize the definitions provided below, unless specifically indicated. 
     The term “building structure” refers to any building, portion of a building or other structure made of construction materials that is exposed to the elements, i.e. rain, wind, water, ice, snow, sun, etc. on a regular basis. Examples of building structures include roofs, building walls, free standing walls, sheds, chimneys, exposed pipes, culverts, above ground or underground tunnels, etc. Examples of construction materials include masonry materials such stone, brick, concrete, etc., wood, metal, insulation, plaster, plasterboard, etc. 
     The term “construction materials” refers to typical materials used in construction such as wood, brick, concrete, metal, insulation materials, etc. 
     The term “majority of a membrane” refers to more than half of the surface area of a membrane. The majority of a membrane includes one adhesive on its surface to allow the membrane to be adhered to a building structure. A second adhesive may be used to adhere the edges of the membrane to the surface of the building structure or to a second membrane overlapped by a first membrane. Also, the edges of a membrane may be left free of adhesive to allow the use of other means to fasten a membrane to a building structure. 
     The term “weather proofing” refers to the conventional meaning of the term weatherproofing i.e. protecting building structures such as roofs, chimneys, walls, etc. from the elements, i.e. rain, wind, water, ice, snow, sun. 
     The term “dead load shear capable adhesive” refers to any adhesive having the property of reliably adhering the weight of a covering membrane, such as a roofing membrane and/or building peripheral at the upper and lower service temperatures of the covering system. A dead load sheer adhesive is capable of holding 20 grams per square inch at room temperature for 2 hours. Preferred dead load sheer capable adhesives are capable of holding 50 grams per square inch at 70° C. (158° F.) for 24 hrs. An example of a dead load shear capable adhesive is Adco PSA-3™ manufactured by Adco Products, Inc. 
     The term “fire retardants” or “FRs” refer to a conventional additives blended into a polymer to reduce the flammability of a polymer by slow down the rate of combustion. Examples of preferred FRs include magnesium hydroxide, brominated FR, SbO 3 , etc. 
     The term “flexible” refers to any material that is capable of being bent, twisted, bowed, curved, etc. For example, a flexible material may be a material that is capable of being formed into a coil and capable of being unrolled from a coil to lie substantially flat. A flexible material may have the capability to be coiled in any direction. Alternatively, a flexible material may be a material that is capable of being repeatedly folded and unfolded. The term “flexible” refers to any material that is capable of being bent, twisted, bowed, curved, etc. 
     The term “horizontal” surface refers to any surface that includes a horizontal dimension, i.e. extends in a direction substantially parallel with the ground. Examples of horizontal surfaces include roof substrates, roofing membranes mounted on roof substrates, etc. 
     The term “roof deck” refers to the conventional meaning of the term roof deck, i.e. a structural supporting surface of a building extending between the surrounding exterior walls of the building. A roof deck may be constructed from plywood, metal decking or concrete or any other suitable material or combination of materials and may include insulation material. 
     The term “roof substrate” refers to the part of a roof on which a roofing membrane is mounted. The roof substrate may be constructed from plywood, metal decking or concrete or any other suitable material or combination of materials and may include insulation or other layers on which the roofing membrane is mounted. 
     The term “roofing membrane” refers to the conventional meaning of the term roofing membrane, i.e. a membrane that is a water impermeable sheet of polymeric material that is secured to a roof deck. A roofing membrane may use polymeric materials such as ethylene propylene diene terpolymer rubber (EPDM), chlorinated polyethylene, PVC, chlorosulfanated polyethylene, TPO, etc. The roofing membrane may be made from a blended composite polymer having additives, such as UV screeners, UV absorbers, fire retardants, etc. to improve weatherability. 
     The term “room temperature thermoplastic” refers to a thermoplastic that is solid at room temperature, i.e. will not cold flow at room temperature. 
     The term “thermoplastic” refers to the conventional meaning of thermoplastic, i.e. a compound substance that exhibits the property of a material, such as a high polymer, that softens when exposed to heat and generally returns to its original condition when cooled to room temperature. Examples of thermoplastics suitable for use include thermoplastics such as: PVC and thermoplastic polyolefins such as polyethylene (PE), linear polyethylene (LPE), polybutenes (PB), polypropylene (PP), co-polymers of polyolefins, ethylene-propylene rubber (EPR), ethylene-propylene copolymer (EPM), EPDM blended with PP or PE or copolymer, etc. 
     The term “thermoplastic polyolefin” (TPO) refers to the conventional meaning of the term thermoplastic polyolefin, i.e. polyolefins that are thermoplastics. Examples of TPO&#39;s that are suitable for use in the present invention include: LPE, PE, PB, PP, co-polymers, EPR or EPDM blended with PP or PE or copolymer, etc. 
     The term “UV absorber” refers to any conventional additive blended into a polymer to stabilize the adverse effects of light exposure, such as a loss of strength, degradation and decoloration. The use of a UV absorber may allow at least one layer of roofing membrane to exhibit good weathering characteristics. Examples of preferred UV absorbers additives include benzotriazole, benezophenones, hindered amine light stabilizers (HALS), non-interacting HALS (NOR-HALS), etc. 
     The term “UV screener” refers to a conventional additive blended into a polymer to reflect ultraviolet rays. Examples of preferred UV screener additives include TiO 2 , carbon black, zinc oxide, etc. 
     By employing a fabric layer bonded to a thermoplastic membrane, the covering product of the present invention is able to employ cheaper adhesives than would be necessary if the roofing membrane was adhered to a roof substrate directly. For example, several relatively cheap adhesives will not bond to a thermoplastic membrane. Other adhesives will react with some types of thermoplastic membranes thereby weakening the adhesives. Other adhesives may react with the monomeric plasticizer present in a PVC roofing membrane. Additionally, the fabric layer also allows lesser amounts of many types of adhesives to be used to adhere a membrane to a roof substrate due to the way that the surface of the fabric material interacts with the surface of the roof substrate. For example, when a roof substrate has a rough surface, a fleece or other type of fabric layer is able to more easily conform to the surface of the roof substrate than a thermoplastic membrane is able to conform to the surface of the roof substrate by itself. Furthermore, a fabric layer is able to provide protection to the membrane from any residual asphalt present on a roof substrate. 
       FIG. 1  illustrates a section of a covering product  112  of the present invention that includes a thermoplastic membrane  114  to which is adhered a fabric material  116 . An adhesive  118  is coated on fabric material  116  and a release liner  120  covers adhesive  118 . An exposed section  122  of membrane  114  is left uncovered by fabric material  116 . 
       FIG. 2  illustrates a section of a roofing product  212  of the present invention that includes a thermoplastic roofing membrane  214  to which is adhered a fabric material  216 . An adhesive  218  is coated on fabric material  216  and a release liner (not shown) was removed from adhesive  218 . An exposed section  222  of roofing membrane  214  is left uncovered by fabric material  216 . Roofing product  212  mounted on a roof substrate  240  so that covering product  212  overlaps a second covering product  242  at an overlap region  244 . Release liner (not shown) has been removed from adhesive  218  so that roofing product  212  may be adhered to roof substrate  240  by adhesive  218 . Similarly, a release liner (not shown) has been removed from an adhesive  248  coated on a fabric material  250  bonded to a roofing membrane  252  of roofing product  242  to allow roofing product  242  to be adhered to roof substrate  240 . Exposed section  222  of roofing membrane  214  is hot air welded to an overlapped section  258  of an upper surface  260  of roofing membrane  252 . 
       FIG. 3  illustrates a section of a covering product  312  of the present invention that includes a thermoplastic membrane  314  to which is adhered a fabric material  316 . An adhesive  318  is coated on fabric material  316  and a release liner  320  covers adhesive  318 . An exposed section  322  of membrane  314  is left uncovered by fabric material  316  and a pressure sensitive adhesive  332  is applied directly to a portion of exposed section  322 . A release liner  334  covers adhesive  332 . 
       FIG. 4  illustrates a section of a roofing product  412  of the present invention that includes a thermoplastic roofing membrane  414  to which is adhered a fabric material  416 . An adhesive  418  is coated on fabric material  416  and a release liner (not shown) was removed from adhesive  418 . An exposed section  422  of roofing membrane  414  is left uncovered by fabric material  416  and a pressure sensitive adhesive  432  is applied directly to a portion of exposed section  422 . A release liner (not shown) is removed from adhesive  432 . Roofing product  412  is mounted on a roof substrate  440  so that roofing product  412  overlaps a second roofing product  442  at an overlap region  444 . Release liner (not shown) has been removed from adhesive  418  so that roofing product  412  may be adhered to roof substrate  440  by adhesive  418 . Similarly, a release liner (not shown) has been removed from an adhesive  448  coated on a fabric material  450  bonded to a roofing membrane  452  of roofing product  442  to allow roofing product  442  to be adhered to roof substrate  440 . Release liner (not shown) has been removed from adhesive  432 , to allow exposed section  422  of roofing membrane  414  to be adhered to an overlapped section  458  of an upper surface  460  of roofing membrane  452 . 
       FIG. 5  illustrates a section of a covering product  512  of the present invention that includes a thermoplastic membrane  514  to which is adhered a fabric material  516 . An adhesive  518  is coated on fabric material  516  and a release liner  520  covers adhesive  518 . Adhesive  518  covers an entire lower surface  522  of fabric material  516 . 
       FIG. 6  illustrates in simplified form a section of a covering product  622  that is applied to an underside  604  of an upper portion  606  of a tunnel  608 . Covering product  602  includes a thermoplastic membrane  614  to which is adhered a fabric material  616 . An adhesive  618  is coated on fabric material and adheres covering product  602  to tunnel  608 . Prior to adhering membrane  612  to tunnel  608 , adhesive  618  is covered by a release liner (not shown). 
     Although for simplicity, only a single membrane is shown being used in the embodiment of  FIG. 6 , a series of overlapping membranes may also be used to cover the interior of a tunnel. 
     Preferred pressure sensitive adhesives for coating on a fabric layer include styrene-butadiene adhesives such as Kraton™ adhesives (manufactured by the Shell Oil Company), amorphous polypropylene, and various other types of adhesives that allow a fabric material to be adhered to a roof substrate. The thickness of the coating of pressure sensitive adhesive may vary depending on the type of fabric material employed and the type of adhesive used. 
     A preferred dead load shear capable adhesive for use with the covering system and flashing is Adco PSA-3™ manufactured by Adco Products, Inc. Adco PSA-3™. Adco PSA-3™ is a pressure sensitive adhesive composition comprising styrene-ethylene-butylene-styrene (SEBS), a tackifying endblock resin such as a cumarone-indene resin and a tackifying midblock resin such as a terpene resin. Other preferred dead load shear capable adhesives include: butyl-based adhesives, EPDM-based adhesives, acrylic adhesives, styrene-butadiene adhesives, polyisobutylene adhesives, ethylene vinyl acetate adhesives, etc. 
     One type of dead load shear capable adhesive may be used for all of the roofing membranes and roofing peripherals of a system, or different adhesives may be used for different components. Also, different adhesives may be used on different sections of a component. For example, a stronger adhesive or a more moisture resistant adhesive may be used to adhere two overlapping membranes to each other while a weaker and possibly cheaper adhesive may be used to adhere the non-overlapping portion of the roofing membrane to a roof substrate. 
     A preferred thickness of a dead load shear capable adhesive may be 0.001 to 0.5 cm. A more preferred thickness of a dead load shear capable adhesive may be 0.01 to 0.25 cm. Yet another more preferred thickness of a dead load shear capable adhesive may be 0.1 to 0.2 cm. 
     The fabric layer is preferably a non-woven or woven polyester fleece, a fleece made from non-woven or woven polyethylene or polypropylene, or other common fabric materials. The fabric layer may be bonded to the roofing membrane using conventional methods. The thickness of the fabric layer may be varied depending on the surface texture of the roof substrate on which a roofing membrane is to be mounted. 
     The exposed section of the roofing membrane is preferably about 2.54 cm (1 in.) to 15.24 cm (6 in.) wide. 
     The release liners used to cover the adhesive coated on the fabric material and/or the adhesive coated on an exposed section of a roofing membrane may be made of any suitable release liner material such as waxed paper, plastic, etc. Using a pressure sensitive adhesive and release liner allows easier storage and transportation of a roofing membrane. The use of a release liner or liners allows for the roofing membrane to be stored and transported as a roll. 
     Although only a few ways of bonding an overlapping exposed section of a roofing membrane to an upper side of an overlapped roofing membrane are shown in the drawing figures and described above, other methods of joining two roofing membranes may be used. For example, instead of directly hot air welding an overlapping exposed section of one roofing membrane to an overlapped section of another roofing membrane, a hot melt adhesive may be applied to the underside of the overlapping section or the upper side of the overlapped section by spraying or knife coating methods. A hot melt adhesive layer may also be co-extruded with a roofing membrane in the region of the exposed section of the roofing membrane. 
     In other alternative embodiments, a transfer adhesives, an solvent based adhesive, or a water based adhesive may be applied to the underside of the overlapping section or the upper side of the overlapped section by traditional adhesive coating methods. 
     In another alternative embodiment, an overlapping section of one roofing membrane may be chemically welded to an overlapped section of a second roofing membrane using known techniques. 
     Although for convenience, the covering product of the present invention is only described above as being applied from above to a horizontal surface or from below to a curved surface, the covering product may also be used on slanted surfaces, such as slanted or peaked roofs, vertical surfaces, such as walls, chimneys, etc., curved surfaces such as culverts, or contoured surfaces, such as terra cotta roofs, or may be applied from below to horizontal and vertical surfaces such as roof overhangs or various curved or contoured surfaces. 
     The membrane of the present invention may be colored to be less noticeable when applied to a building structure. 
     Also, although only a few types of building structures are depicted as being covered in the embodiments of the present invention described above and illustrated in the drawings, the covering products of the present invention drawings, the covering products of the present invention may be used on a variety of building structures. 
     Although the present invention has been fully described in conjunction with the preferred embodiment thereof with reference to the accompanying drawings, it is to be understood that various changes and modifications may be apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims, unless they depart therefrom.