Patent Application
20080097004
Roofing membranes according to the present invention include infrared reflective compounds.
Roofing membranes include those typically employed on flat or low-slope roof systems. These membranes include those fabricated from compositions comprising ethylene-propylene-diene rubber (EPDM), thermoplastic olefins (TPO), thermoplastic vulcanizates (TPV), and polyvinyl chloride (PVC).
Useful EPDM membranes include those that are conventional and commercially available in the art. For example, EPDM membranes are commercially available under the tradename RUBBERGARD from the Firestone Building Products Company (Carmel, Ind.). Also, EPDM roofing membranes are disclosed in numerous United States patents including U.S. Pat. Nos. 3,280,082, 4,732,925, 4,810,565, 5,162,436, 5,286,798, 5,370,755, 5,242,970, 5,512,118, 2,260,111, 5,256,228, 5,582,890, 5,204,148, 5,389,715, 5,854,327, 5,054,327, and 5,700,538, which are incorporated herein by reference. Useful thermoplastic olefin membranes are available under the tradename ULTRAPLY™ TPO, and useful polyvinyl chloride membranes are available under the tradename ULTRAPLY™ PVC.
The EPDM membranes comprise EPDM or EPM. EPDM refers to terpolymers of ethylene, propylene, and diene monomer as defined in ASTM-D-1418-85. EPM refers to copolymers that contain from about 55 to about 70 weight percent ethylene with the balance being propylene as defined in ASTM-D-1418-85. EPDM membranes are preferably cured by using a curative in the formulation. Typically, the curatives are used in conjunction with various accelerators, the combination of which is often referred to as a cure package. Preferably, the cure package will include from about 1.5 to about 10 parts by weight per 100 parts by weight EPDM of a sulfur cure package that includes one organic vulcanizing accelerator.
EPDM membranes may also include extender oils, processing aids such as various metal salts of stearic acid, sodium dodecyl sulfate as well as tackifying resins, plasticizers, antioxidants, antiozonants, waxes, cure accelerators, zinc oxide, stearic acid, UV stabilizers, and the like.
The infrared reflective materials employed in the present invention, which may also be referred to as infrared reflective fillers or pigments, include those substances or compounds that reflect solar radiation in the infrared spectrum. Preferably, these materials will have increased reflectivity in the infrared region over that in the visible light region (i.e., they provide greater reflectivity in the infrared region than in the visible region). Some especially preferred materials will also have increased reflectivity in the ultraviolet region over that in the visible light region. Preferably, these materials will absorb a significant amount of solar energy within the visible light spectrum and thereby provide a dark color such as a green, brown, blue, or black color.
Infrared reflective materials are known and commercially available. For example, black pigments that reflect infrared solar radiation include those available from Degussa Metal Catalysts Cerdec Corporation. These include those available under the tradenames Eclipse™ Black 01201, Eclipse™ Black 10202, Eclipse™ Black 10203, and Eclipse™ Black 10204. Others include those under the tradename Cool Colors™, which are available from the Ferro Corporation of Cleveland, Ohio.
One useful infrared reflective material includes solid solutions including corundum-hematite crystalline structures. These solid solutions are disclosed in U.S. Pat. Nos. 6,454,848, 6,487,830, and U.S. Patent Application Publication No. US2004/0009319 A1, which are incorporated herein by reference.
The roofing membranes of the present invention preferably include from about 2 to about 100 parts by weight, more preferably from about 3 to about 95 parts by weight, more preferably form about 5 to about 90 parts by weight, even more preferably from about 10 to about 95 parts by weight, still more preferably from about 25 to about 65 parts by weight, and even more preferably form about 30 to about 50 parts by weight infrared reflective material per 100 parts by weight polymer.
The membranes of the present invention can be fabricated by employing standard techniques employed in the industry. The infrared reflective materials can be added to those formulations used in the membrane fabrication processes. Preferably, especially in the case of EPDM membranes, the infrared reflective material is added during the rubber compounding or mixing stage, which may employ standard Banbury or similar mixing equipment.
The membranes of this invention are incorporated into standard commercial roof systems. These roof systems generally include a roof deck, which is typically the structural supporting surface of a building extending between surrounding exterior walls of the building. The roof deck may be constructed from plywood, metal decking, concrete or any other suitable material. Depending upon the construction, the roof deck may extend over the surrounding exterior walls or the roof deck may stop short of the exterior walls, thereby forming a parapet wall, i.e., a low retaining wall at the edge of the roof deck. If desired, the roofing system may also include an insulation barrier formed from polyisocyanurate or any other suitable material applied over the roof deck.
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.
This application gains benefit from U.S. Provisional Patent Application No. 60/466,925, filed on May 1, 2003.
| Number | Date | Country | |
|---|---|---|---|
| 60466925 | May 2003 | US |
