Abstract:
The present invention provides a non-asphaltic peel-and-stick roofing membrane for quicker and easier installation to a roof substrate, as well as a method of manufacturing the membrane.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to roofing membranes. More specifically, the present invention relates to non-asphaltic peel-and-stick roofing membranes for quicker and easier installation.  
       BACKGROUND OF THE INVENTION  
       [0002]     A single-ply building membrane is a membrane typically applied in the field using a one layer membrane material (either homogeneous or composite) rather than multiple layers built-up. These membranes have been widely used on low slope roofing and other applications. The membrane can comprise one or more layers, have a top and bottom surface, and may include a reinforcing scrim or stabilizing material. The scrim is typically of a woven, nonwoven, or knitted fabric composed of continuous or discontinuous strands of material used for reinforcing or strengthening membranes.  
         [0003]     These single-ply membranes typically comprise base (bottom) and cap (top) polyolefin-based sheets (layers) with a fiber reinforcement scrim (middle) sandwiched between the other two layers. The scrim is generally the strongest layer in the composite. Other materials from which the membranes may be formed, include but are not limited to, polyvinyl chloride (PVC), chlorosulfonated polyethylene (CSPE or CSM), chlorinated polyethylene (CPE), and ethylene propylene diene polymer (EPDM).  
         [0004]     Current non-asphaltic roll membranes which are self adhering, such as those based on TPO and PVC membrane, require cleaning of side laps areas. Often this is followed by a solvent-based priming step. Both the cleaning step and the priming step together significantly slow down the installation of these self-adhering products.  
         [0005]     The side lap is the continuous longitudinal overlap of neighboring like materials. Presently, side lap preparation requires the application of cleaners or primers on to the side lap of the membrane by brushing and/or rolling. Additionally, many primers and cleaners are caustic and can irritate or burn the roofer&#39;s hands and skin.  
       SUMMARY OF THE INVENTION  
       [0006]     The present invention is directed to a non-asphaltic single-ply roofing membrane in which the side lap area is factory modified such that the surface modification consists one or more of the following: 
        a. Application of a cleaning step, which may or may not, involve organic solvents such as toluene, heptane, xylene, methyl ethyl ketone (MEK), ethylbenzene, naphtha or other hydrocarbons, etc. or a mixture thereof. In many cases (depending on the nature of substrate), only a dry wipe cleaning (with a cloth) is satisfactory to rid the surface of dust, foreign matter and even oil stains;     b. Application of a primer consisting of any of the above-mentioned organic solvents or a mixture thereof;     c. Application of a hot adhesive over a dust-free side lap area.        
 
         [0010]     With regard to the application of a hot adhesive, priming is generally unnecessary as the hot adhesive forms excellent bond with the substrate (weather side of single-ply membrane) without primer. In this case, a release liner may be necessary over such a factory-modified seam so as to prevent unintended sticking to the back side of the roll. The adhesive application in the side lap area (on the weather side) can be favorably and more preferably achieved by coating the melted adhesive by any of the common methods (such as roll coating, slot die coating, doctor blade coating, etc.) well known to those practicing the art.  
         [0011]     Any one or more of these steps are accomplished at the factory during the manufacture of finished roll products. A combination of steps (a) and (b) or steps (a) and (c) above allows elimination of the following during installation over the roof:  
         [0012]     (1) cleaning and/or priming the seam;  
         [0013]     (2) applying an adhesive tape or spraying an adhesive with the intention to form a side-lap  
         [0014]     The membrane according to the present invention comprises a single-ply membrane having a lower surface and an upper surface, the upper surface having side lap area defined at diametrically opposite borders of the membrane, a primer and/or cleaner applied on the side lap area, an adhesive coated on the primer and/or cleaner applied on the side lap area; and a removable release liner applied on the adhesive.  
         [0015]     The preparation of the membrane in accordance with the present invention comprises the steps of pre-cleaning/pre-priming the side lap of a single-ply membrane having an adhesive layer and release liner on its deck side, coating the side lap with an adhesive material, applying a release liner on the adhesive material, and rolling the membrane for storage and later application on a roof substrate.  
         [0016]     The above and other features of the invention, including various novel details of construction and combinations of parts, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular device embodying the invention is shown by way of illustration only and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention. 
     
    
     BRIEF DESCRIPTION OF THE FIGURE  
       [0017]     These and other features, aspects, and advantages of the apparatus and methods of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:  
         [0018]      FIG. 1  is a schematic side view of one embodiment of the membrane in accordance with the present invention;  
         [0019]      FIG. 2  is a schematic side view of a second embodiment of the membrane in accordance with the present invention; and  
         [0020]      FIG. 3  is a schematic side view of a third embodiment of the membrane in accordance with the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0021]     Although this invention is applicable to numerous and various roofing structures, it has been found particularly useful in the environment of single-ply roofing membranes. Therefore, without limiting the applicability of the invention to single-ply roofing membranes, the invention will be described in such environment.  
         [0022]     As used herein, the term “roofing membrane” generally refers to refers to the conventional meaning of the term roofing membrane, i.e. 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 polymer rubber (EPDM), chlorinated polyethylene, PVC, chlorosulfonated polyethylene, thermoplastic polyolefin (TPO), etc. The roofing membrane may be made from a blended composite polymer having additives, such as UV screeners, UV absorbers or stabilizers, fire retardants, etc. to improve weatherability.  
         [0023]      FIG. 1  is a schematic representation of the layers of the non-asphaltic membrane in accordance with one embodiment of the present invention. In  FIG. 1 , sheet  10  includes a substrate or membrane  12 , which may be TPO or PVC, but is not limited thereto. Membrane  12  has a deck side  14 , which is the side of membrane  12  that is applied on a roof substrate (not shown). The opposite side of membrane  12  is referred to as the weather side  16 , which is the side that exposed to the environment when deck side  14  of membrane  12  is applied to a roof substrate. A first adhesive layer  18  is coated on deck side  14  of membrane  12 . A release liner  20  is then placed upon first adhesive layer  18 . When sheet  10  is to be applied to a roof substrate, release liner  20  is peeled off first adhesive layer  18 . Sheet  10  is then positioned on the roof substrate and is adhered thereto by first adhesive layer  18 . This type of sheet is thus commonly referred to as a “peel and stick” membrane.  
         [0024]     The border/edge of membrane  12  is commonly earmarked as the side lap area  22 . Side lap  22  extends lengthwise along the entirety of membrane  12 . Depending upon the type of membrane, side lap  22  generally has a width in the range of approximately 1 inch to 20 inches. More preferably, the width of side lap  22  is in the range of approximately 3 to 6 inches. As explained hereinabove, side lap  22  is a generally a continuous longitudinal overlap of neighboring like materials, i.e. sheets  10 . In accordance with the present invention, side lap  22  is cleaned and/or primed with commonly used roofing cleaners and/or primers. The cleaners and/or primers are coated directly on side lap  22  on weather side  16  of membrane  12 . A second layer of adhesive  24 , which may be the same or different from first adhesive layer  18 , is then coated on the pre-cleaned/pre-primed side lap  22 . A release liner  26  is preferably applied upon second adhesive layer  24  coated on side lap  22 . Depending upon the cleaner/primer applied on side lap  22 , liner  26  may be optional. For example, certain adhesives are heat-activated or pressure sensitive. Such adhesives may not be immediately tacky and thus there is no need for a liner.  
         [0025]     Adhesive layer on  24  that is applied on side lap  22  of weather side  16  of membrane  12  allows for overlapping one roll over another lengthwise when applied on a roof substrate.  
         [0026]     In another embodiment illustrated in  FIG. 2 , sheet  10  is provided as described immediately above, and wherein side lap  22  having cleaner and/or primer thereon (indicated by  24 ) has 10-90% of thickness of first adhesive layer  18 .  
         [0027]     In another embodiment as illustrated in  FIG. 3 , sheet  10  is provided as discussed immediately above in the second embodiment. In this embodiment, however, first adhesive layer  18  in the area corresponding to side lap  22  on deck side  14  of membrane  12  is reduced more than, less than or equal to the thickness of second adhesive layer  24  applied on side lap  22  on weather side  16  of membrane  12 . The reduced area is indicated at  30 .  
         [0028]     In all of the embodiments in accordance with the present invention, membrane  12  is preferably a thermoplastic single-ply membrane but is not limited in this regard. Membrane  12  may be modified bitumen or thermoset or thermoplastic membrane preferably polyvinyl chloride (PVC) and other resinous compositions containing polyvinyl chloride, chlorosulfonated polyethylene (CSPE or CSM), chlorinated polyethylene (CPE), ethylene propylene diene polymer (EPDM), APP modified bitumen, SBS modified bitumen, or a thermoplastic olefin (TPO).  
         [0029]     In accordance with the present invention, the side lap area is factory modified such that the surface modification consists one or more of the following: 
        a. Application of a cleaning step, which may or may not, involve organic solvents such as toluene, heptane, xylene, methyl ethyl ketone (MEK), ethylbenzene, naphtha or other hydrocarbons, etc. or a mixture thereof. In many cases (depending on the nature of substrate), only a dry wipe cleaning (with a cloth) is satisfactory to rid the surface of dust, foreign matter and even oil stains;     b. Application of a primer consisting of any of the above-mentioned organic solvents or a mixture thereof;     c. Application of a hot adhesive over a dust-free side lap area.        
 
         [0033]     With regard to the application of a hot adhesive, priming is generally unnecessary as the hot adhesive forms excellent bond with the substrate (weather side of single-ply membrane) without primer. In this case, a release liner may be necessary over such a factory-modified seam so as to prevent unintended sticking to the back side of the roll. The adhesive application in the side lap area (on the weather side) can be favorably achieved by coating the melted adhesive by any of the application methods commonly used in applying roofing materials, such as roll coating, slot die coating, doctor blade coating, etc.  
         [0034]     Any one or more of the above-mentioned steps are accomplished at the factory during the manufacture of finished roll products.  
         [0035]     In preparing sheet  10  at a factory in accordance with the described embodiments, a long strip of membrane  12  is extended along a surface. A side lap area  22  is defined on weather side  16  of membrane  12 . Side lap  22  is then cleaned and pre-primed. Second adhesive layer  24  is then coated upon the cleaned and pre-primed side lap  22 . Release liner  26  is then placed on second adhesive layer  24 . Sheet  10  is then rolled for storage and later application on a roof substrate.  
         [0036]     First and second adhesive layers  18  and  24  may be any adhesive or glue commonly used in the roofing industry for applying membranes to a roof substrate. Nonlimiting examples of adhesives include, but are not limited to, polyurethane, ethylene-butylene-styrene, and other known deal load shear capable adhesives such as Adco PSA-3™, manufactured by Adco Products, Inc. Other common pressure sensitive adhesives are butyl rubber based (containing polyisobutene and/or polyisoprene or polybutenes) or styrene-butadiene-styrene (SBS), styrene-ethylene-butadiene-styrene (SEBS), styrene-isoprene-styrene (SIS), acrylics, etc.  
         [0037]     First and second adhesive layers  18 ,  24 , in accordance with the present invention, has excellent tack and quick stick properties. The adhesive resists extreme heat and cold. Additionally, the adhesive may be used with a roofing article such as EPDM rubber or TPO to provide a watertight seal. The adhesive may be used in a variety of weather conditions, and no special equipment is required. Additionally, the adhesive poses no environmental hazard and does not require hazardous solvents.  
         [0038]     The primers and/or cleaners which may be applied on side lap  22  include, but are not limited to, Heptanes, Toluene, Methyl Alcohol, Hexane, Xylene, Methyl ethyl ketone (MEK), Diphenylmethane Diisocyanate, Polymethylene Polyphenol Isocyanate, Ethylbenzene, Naphtha, Hydrocarbon Resins and Halogenated Butyl or a suitable mixture thereof. These liquids can be used individually or in various mixtures with each other or with additional ingredients.  
         [0039]     Release liners  20  and  26  may be any suitable release liner material such as waxed paper, polycoated paper, film based paper or a plastic commonly associated with silicon chemistry. Release liners  20 ,  26  facilitate acceptable package, storage, and installation performance. The release system exhibits little or no affinity for the adhesive and exhibits no negative impact on the initial tackiness of the adhesive, and on the subsequent utility of the adhesive in application and long term performance. In addition, the release system permits ready manual separation of the shingles or tiles at ordinary ambient temperatures. Practically, release liners  20 ,  26  include, for example, sheet materials including various films (i.e., cellophane, polyester, polypropylene, polyethylene, polyvinylalcohol and polyvinylchloride), paper, foil and the like which have been subjected to surface-treatment such as coating and/or impregnating with synthetic resins having high release properties (e.g., silicone resins and fluorocarbons). Release liners  20 ,  26  may optionally be treated with a release agent such as silicone resin and fluorine containing resins).  
         [0040]     While there has been shown and described what is considered to be preferred embodiments of the invention, it will, of course, be understood that various modifications and changes in form or detail could readily be made without departing from the spirit of the invention. It is therefore intended that the invention be not limited to the exact forms described and illustrated, but should be constructed to cover all modifications that may fall within the scope of the appended claims.